JP2012188000A - Driving force transmission device for four-wheel drive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a four-wheel drive vehicle without reducing fuel economy in two-wheel drive mode by reducing friction loss by completely stopping rotation of a part having no relevance to transmission of driving force in the two-wheel drive mode.SOLUTION: This driving force transmission device 10 includes: a front-wheel drive part 14 for transmitting driving force from an engine 32 to front wheels 54, 56; a driving force transmission part 16 for distributing driving force from the front-wheel drive part 14 in response to a rotating speed difference between the front and rear wheels through a rotation difference-sensitive coupling 28 to be transmitted to the rear wheel side; a rear-wheel drive part 18 for transmitting the driving force from the driving force transmission part 16 to right and left rear wheels 100, 102 through a rear-wheel differential device 22; a first separation device 24 for disconnecting and connecting the coupling between the front-wheel drive part 14 and the driving force transmission part 16; and a second separation device 26 for disconnecting and connecting the coupling between the rear-wheel drive part 18 and the right rear wheel 102. A synchronization mechanism 94 is arranged in the second separation device 26.

Description

The present invention relates to a driving force transmission device for a four-wheel drive vehicle capable of switching between a two-wheel drive mode and a four-wheel drive mode, and in particular, stops rotation of a portion not related to the transmission of the drive force in the two-wheel drive mode. The present invention relates to a driving force transmission device for a wheel drive vehicle.

  Even in conventional on-demand full-time four-wheel drive vehicles, energy saving measures are required due to environmental problems in recent years. For this reason, in the two-wheel drive mode, the rotation of the part not related to the transmission of driving force is stopped and the fuel consumption is reduced. Techniques for improvement have been proposed.

  An on-demand full-time four-wheel drive vehicle can be switched between a two-wheel drive mode that drives only the main drive wheels and a four-wheel drive mode that always drives the main drive wheels and also drives the auxiliary drive wheels as needed. This is a four-wheel drive vehicle. Among them, in the two-wheel drive mode, the front wheels are driven, and in the four-wheel drive mode, the driving force is distributed to the front and rear wheels through an electronically controlled coupling before the rear axle. As a driving force transmission device for an FF vehicle-based four-wheel drive vehicle that is actively controlled by the above-mentioned, for example, the one described in Patent Document 1 is known, and an example thereof is shown in FIG.

  In FIG. 10, the driving force transmission device 710 of the four-wheel drive vehicle 712 includes a first disconnecting device 724, a second disconnecting device 726, and an electronic control coupling 728. In the four-wheel drive mode, the first disconnecting device 724 and The second disconnecting device 726 is connected, and the driving force from the engine 732 is distributed to the front wheels 754 and 756 and the rear wheels 800 and 802 by the electronic control coupling 728.

  In the two-wheel drive mode, the first disconnecting device 724 and the second disconnecting device 726 are disconnected to interrupt the transmission of the driving force between the two disconnecting devices, so that the driving force transmission unit 716 stops rotating, and this part It is possible to improve the fuel consumption by preventing the oil agitation resistance and the friction loss of the bearing portion.

  In the two-wheel drive mode, the front wheels are driven. In the four-wheel drive mode, the driving force distribution to the front and rear wheels is actively controlled by electronically controlled coupling on the rear axle. As a vehicle driving force transmission device, for example, the one disclosed in Patent Document 2 is known, and examples thereof are shown in FIGS.

  In FIG. 11, the driving force transmission device 810 of the four-wheel drive vehicle 812 includes a first disconnecting device 824, a second disconnecting device 826, and an electronic control coupling 828. In the four-wheel drive mode, the first disconnecting device 824 and The second disconnecting device 826 is connected, and the driving force from the engine 832 is distributed to the front wheels 854 and 856 and the rear wheels 900 and 902 by the electronic control coupling 828.

  In the two-wheel drive mode, the first disconnecting device 824 and the second disconnecting device 826 are cut so that the transmission of the driving force between the two disconnecting devices is cut off, so that the rotation of the driving force transmitting portion 816 stops, and this portion It is possible to improve the fuel consumption by preventing the oil agitation resistance and the friction loss of the bearing portion.

  In FIG. 12, the driving force transmission device 910 of the four-wheel drive vehicle 912 includes a first disconnecting device 924 and electronic control couplings 926 and 928, and in the four-wheel drive mode, the first disconnecting device 924 is connected to the engine. The driving force from 932 is distributed to front wheels 954 and 956 and rear wheels 1000 and 1002 by electronic control couplings 926 and 928.

In the two-wheel drive mode, the first disconnecting device 924 is disconnected and the transmission torque of the electronic control couplings 926 and 928 is controlled to zero to transmit the driving force between the first disconnecting device 924 and both electronic control couplings. By shutting off, the rotation of the driving force transmission unit 916 stops, and it is possible to improve the fuel consumption by preventing the oil agitation resistance of this portion and the friction loss of the bearing portion.

JP 2009-292307 A JP 2009-269605 A JP 2002-310196 A Japanese Unexamined Patent Publication No. 63-240429

  However, in the conventional driving force transmission device as shown in FIGS. 10 and 11, the cost is increased by adding two separation devices to the front axle and the rear axle, compared to the configuration in which the separation device is not provided. There is a problem of becoming.

  In the configuration in which the separation device is not provided, the two-wheel drive mode is set by controlling the transmission torque of the electronically controlled coupling to zero. In such a configuration, the driving force is transmitted in the two-wheel drive mode. Since the driving force transmission portion not related to the rotation rotates, the oil agitation resistance in this portion, the friction loss of the bearing portion, and the like occur, resulting in a reduction in fuel consumption.

  In addition, in the conventional driving force transmission device as shown in FIG. 12, as compared with the configuration in which the separation device is not provided, the separation device is added to the front axle, and two electronically controlled couplings are added to the rear axle. There is a problem of increased costs.

  Further, in the driving force transmission device of FIG. 11, the torque-on-demand type (variable transmission torque type) electronically controlled coupling 828 is disposed on one side of the differential device 822, so that the torque bias ratio of the differential device 822 is increased. (Ratio of torque transmitted between the gripping tire and the slipping tire) may adversely affect vehicle stability. For this reason, it is necessary to take measures to suppress the friction of the differential device 822 so that the torque bias ratio is close to “1”.

The present invention achieves a low power transmission device for a four-wheel drive vehicle that does not cause a reduction in fuel consumption in the two-wheel drive mode by completely stopping the rotation of the drive force transmission unit that is not involved in the transmission of the drive force in the two-wheel drive mode. The purpose is to provide at a cost.

  In order to achieve this object, a driving force transmission device for a four-wheel drive vehicle according to the present invention is configured as follows. The present invention is for a four-wheel drive vehicle capable of switching between a four-wheel drive mode in which drive force is distributed to the first drive wheel and the second drive wheel and a two-wheel drive mode in which the drive force is transmitted only to the first drive wheel. In the driving force transmission device, a first driving unit that transmits driving force from the engine to the first driving wheel, a driving force transmission unit that transmits driving force from the first driving unit to the second driving wheel, and driving A second drive unit that transmits the driving force from the force transmission unit to the second drive wheel, and a rotation-sensitive coupling that distributes the drive force according to the difference in rotation speed between the first drive wheel and the second drive wheel; A first disconnecting device that disconnects and connects the transmission of the driving force from the first driving unit to the driving force transmission unit, and a second disconnecting device that disconnects and connects the transmission of the driving force from the second driving unit to the second driving wheel. And an apparatus.

  Here, the rotation-difference sensitive coupling is disposed between the first separation device and the second drive unit or coaxially with the output shaft of the second drive unit.

  Further, at least one of the first disconnecting device and the second disconnecting device is provided with a synchronization mechanism that synchronizes the rotation of the driving force transmission unit side and the opposing side when connected.

Furthermore, the second disconnecting device cuts and connects the transmission of the driving force from the second driving unit to at least one of the left and right sides of the second driving wheel.

  According to the present invention, in the two-wheel drive mode, since the rotation of the components of the driving force transmission unit is completely stopped by cutting the first separation device and the second separation device, the oil viscosity in this section No resistance or friction loss occurs. Therefore, fuel consumption can be prevented from being lowered, and the fuel consumption when used in the two-wheel drive mode while being a four-wheel drive vehicle can be made the same as that of a two-wheel drive vehicle.

  In addition, the present invention provides a separation device by using passive control using a rotation-difference-sensitive coupling that is less expensive than electronic control coupling, compared to the conventional method of active control of electronic control coupling. Even with the configuration in which two are provided, a four-wheel drive vehicle in which fuel consumption does not decrease in the two-wheel drive mode can be realized at low cost.

Further, even when the synchronization mechanism of one separating device is omitted, by controlling the rotational speed difference between both sides of the other separating device not provided with the synchronizing mechanism by the synchronizing mechanism provided in one separating device, Since the disconnecting device can be connected, the switching from the two-wheel drive mode to the four-wheel drive mode can be reliably performed regardless of the traveling state.

Explanatory drawing which shows 1st Embodiment of the driving force transmission device for four-wheel drive vehicles by this invention. Sectional drawing which shows embodiment of the front-wheel drive part of FIG. Sectional drawing which shows embodiment of the rear-wheel drive part of FIG. 1, and a rotation difference sensitive type coupling Explanatory drawing which shows 2nd Embodiment of the driving force transmission device for four-wheel drive vehicles by this invention. Sectional drawing which shows embodiment of the rear-wheel drive part of FIG. 4, and a rotation difference sensitive type coupling Explanatory drawing which shows 3rd Embodiment of the driving force transmission device for four-wheel drive vehicles by this invention. Explanatory drawing which shows 4th Embodiment of the driving force transmission device for four-wheel drive vehicles by this invention. Explanatory drawing which shows 5th Embodiment of the driving force transmission device for four-wheel drive vehicles by this invention. Explanatory drawing which shows 6th Embodiment of the driving force transmission device for four-wheel drive vehicles by this invention. Explanatory drawing which showed the Example of the conventional driving force transmission apparatus for four-wheel drive vehicles Explanatory drawing which showed other Examples of the conventional driving force transmission device for four-wheel drive vehicles Explanatory drawing which showed other Examples of the conventional driving force transmission device for four-wheel drive vehicles

  Hereinafter, a driving force transmission device for a four-wheel drive vehicle according to the present invention will be described in detail with reference to the drawings showing embodiments. Each embodiment is a four-wheel drive vehicle based on an FF (Front-engine Front-drive) vehicle that drives the front wheels in the two-wheel drive mode, or an FR (Front-engine Rear-drive) that drives the rear wheels in the two-wheel drive mode. ) Shows a car-based four-wheel drive vehicle. In the four-wheel drive vehicle of each embodiment, at least the engine and the driving force transmission device are controlled by an ECU (Electronic Control Unit) based on detection values of various vehicle state detection sensors.

  FIG. 1 is an explanatory view showing a first embodiment of a driving force transmission device for a four-wheel drive vehicle according to the present invention, which is applied to an FF vehicle-based four-wheel drive vehicle.

  In FIG. 1, a driving force transmission device 10 according to this embodiment is provided in a four-wheel drive vehicle 12, and includes a front wheel driving unit (first driving unit) 14, a driving force transmitting unit 16, and a rear wheel driving unit (second driving unit). 18, the front wheel drive unit 14 is provided with a front wheel differential device 20, the driving force transmission unit 16 is provided with a rotation difference sensitive coupling 28, and the rear wheel drive unit 18 is provided with a rear wheel differential device 22. A first disconnecting device 24 is provided between the front wheel differential device 20 and the driving force transmission unit 16, and a second disconnecting device 26 is provided between the rear wheel differential device 22 and the right rear wheel 102.

  Control signals E 1 and E 2 from the ECU 30 are given to the actuator 64 of the first disconnecting device 24 and the actuator 98 of the second disconnecting device 26. The driving force from the engine 32 is shifted by the transmission 34 and then input to the front wheel differential device 20 from the drive gear 36 of the transmission 34. The front wheel differential device 20 converts the driving force from the transmission 34 to the left front wheel. 54 and the right front wheel 56.

  The front wheel differential 20 includes a ring gear 38 that engages with the drive gear 36, a differential case 40 to which the ring gear 38 is fixed, pinions 42 and 44 that are rotatably supported in the differential case 40, and pinions 42 and 44. The ring gear 38 receives the driving force from the drive gear 36, and the left front wheel drive shaft 50 and the right front wheel drive shaft 52 are connected via the pinions 42, 44 and the side gears 46, 48. Driven to rotate the left front wheel 54 and the right front wheel 56 to transmit the driving force to the road surface.

  The front wheel differential device 20 absorbs the rotational speed difference and generates a torque equal to the left front wheel 54 and the right front wheel 56 when a difference in rotational speed occurs between the left front wheel 54 and the right front wheel 56 due to cornering or a change in road surface condition. To rotate.

  The driving force from the drive gear 36 is also input to the first disconnecting device 24 via the ring gear 38 and the differential case 40 of the front wheel differential device 20, and the first disconnecting device 24 is supplied from the ECU 30 in the two-wheel drive mode. In this state, the actuator 64 is driven by the control signal E1 to disconnect the driving force transmission unit 16, and the driving force to the rear wheel side is disconnected. Therefore, in the two-wheel drive mode, the driving force from the engine 32 is not transmitted to the rear wheel side via the driving force transmission unit 16.

  On the other hand, in the four-wheel drive mode, the first disconnecting device 24 is connected to the driving force transmission unit 16 by driving the actuator 64 by the control signal E1 from the ECU 30. Therefore, the driving force input to the first separation device 24 is transmitted from the differential case shaft 58 that rotates integrally with the differential case 40 to the hypoid ring gear shaft 60, and the hypoid ring gear 66 that rotates integrally with the hypoid ring gear shaft 60. The output direction is converted by the output pinion 68 and output.

  The driving force output from the output pinion 68 is transmitted to the drive pinion 76 via the universal joint 70, the propeller shaft 72, the universal joint 74, and the rotation-sensitive coupling 28, and is transmitted from the drive pinion 76 to the rear wheel differential device 22. The direction is transferred to the hypoid ring gear 78.

  The shaft of the drive pinion 76 connected to the rotation difference sensitive coupling 28 serves as the input shaft of the rear wheel drive unit 18. That is, in the present embodiment, the rotational difference sensitive coupling 28 is disposed coaxially with the input shaft of the rear wheel drive unit 18. For example, the first separation device 24 and the hypoid ring gear 66 As long as it is between the first disconnecting device 24 and the rear wheel drive unit (second drive unit) 18, such as between the output pinion 68 and the universal joint 70, it may be disposed anywhere.

  Here, the rotation-difference type coupling does not transmit torque when there is no difference in rotational speed between the input side and the output side, but torque according to the rotational speed difference when there is a difference in rotational speed. It is a coupling that transmits

  Whereas the electronically controlled coupling used in the conventional driving force transmission device shown in FIG. 10-12 is an active coupling that actively changes the transmission torque between the input and output shafts using an actuator. The rotation difference sensitive coupling is a passive coupling in which the transmission torque between the input and output shafts passively changes depending on the rotational speed difference between the input and output shafts.

  Electronically controlled couplings require sensors, controllers, actuators, etc. for control, but rotation-sensitive couplings are much cheaper than electronically controlled couplings because these control mechanisms are not required. is there.

  In the four-wheel drive mode, when there is no difference in rotational speed between the front wheels 54 and 56 and the rear wheels 100 and 102, the rotation-sensitive coupling 28 does not distribute the driving force to the rear wheel drive unit 18, When there is a difference in rotational speed between the front wheels 54 and 56 and the rear wheels 100 and 102, such as when the wheel slips, that is, the driving force transmission portion 16 side of the rotation-sensitive coupling 28 and its opposite side When a rotational speed difference occurs between the rear wheel drive unit 18 and the rotation difference sensitive coupling 28, the driving force corresponding to the rotational speed difference is distributed to the rear wheel drive unit 18.

  The rear wheel differential 22 includes a hypoid ring gear 78 that engages with the drive pinion 76, a differential case 80 to which the hypoid ring gear 78 is fixed, pinions 82 and 84 that are rotatably supported in the differential case 80, and a pinion The left rear wheel drive shaft 90 connected to the side gear 86, the second separating device 26 connected to the side gear 88, and the right rear wheel drive shaft 92 are configured by side gears 86, 88 that engage with the side gears 86, 84. The wheel 100 and the right rear wheel 102 are rotated to transmit the driving force to the road surface.

  In the present embodiment, the second disconnecting device 26 is provided in the middle of the right rear wheel drive shaft 92 that connects the rear wheel differential 22 and the right rear wheel 102, and connects and disconnects the driving force to the right rear wheel 102. However, the position of the second separating device 26 is not limited to this, and may be provided in the middle of the left rear wheel drive shaft 90 or inside the rear wheel differential device 22.

  In the two-wheel drive mode, the second disconnecting device 26 is controlled to be disconnected by driving the actuator 98 by a control signal E2 from the ECU 30, and transmission of driving force between the right rear wheel 102 and the rear wheel differential device 22 is performed. In the four-wheel drive mode, the actuator 98 is driven by the control signal E2 from the ECU 30 to be controlled to be in the connected state, and from the engine 32 via the rotation-sensitive coupling 28 and the rear wheel differential 22. The driving force is transmitted to the right rear wheel 102.

  That is, in the four-wheel drive mode, the rear wheel differential device 22 operates effectively, and even if a difference in rotational speed occurs between the left rear wheel 100 and the right rear wheel 102 due to cornering or changes in road surface conditions, the rear wheel differential The device 22 can absorb the rotational speed difference and rotate the left rear wheel 100 and the right rear wheel 102 with equal torque.

  In the present embodiment, as will be described in detail with reference to FIGS. 2 and 3, a meshing clutch mechanism 96 having a meshing clutch mechanism 62 as the first detaching device 24 and a synchronizing mechanism 94 as the second detaching device 26. The actuators 64 and 98 can be driven to switch between a disconnected state in which the two-wheel drive mode is set and a connected state in which the four-wheel drive mode is set.

  FIG. 2 is a cross-sectional view showing the front wheel drive unit 14 of FIG. 1, and the upper side of the drawing is the front side (forward direction) of the four-wheel drive vehicle 12. In FIG. 2, the front wheel differential device 20, the first disconnecting device 24, the hypoid ring gear 66 and the output pinion 68 are accommodated in a housing 104 connected to the transmission 34. The housing 104 is divided into a plurality of parts, each of which is fastened with a bolt.

  The front wheel differential device 20 located on the left side of the housing 104 includes a ring gear 38 fixed to the flange portion 40a of the differential case 40, and pinions 42, 44 rotatably supported on a pinion shaft 106 fixed to the differential case 40. A side gear 46 is rotatably supported by the differential case 40 and connected to the left front wheel drive shaft 50 in a non-rotatable manner. A side gear 48 is rotatably supported by the differential case 40 and is connected to the right front wheel drive shaft 52 in a non-rotatable manner.

  The ring gear 38 is engaged with the drive gear 36 of the transmission 34, and the side gears 46 and 48 are engaged with the pinions 42 and 44, respectively. The differential case 40 is rotatably supported by the housing 104 on both the left front wheel drive shaft 50 side and the right front wheel drive shaft 52 side by tapered roller bearings 108 and 110, respectively.

  On the right side of the housing 104, there is provided a hypoid ring gear shaft 60 in which a hypoid ring gear 66 is non-rotatably fitted coaxially with the differential case 40. The hypoid ring gear shaft 60 is provided on both sides of the differential case 40 side and the hypoid ring gear 66 side. Tapered roller bearings 112 and 114 are rotatably supported on the housing 104, respectively.

  An output pinion 68 that engages with the hypoid ring gear 66 is disposed on the lower right side of the housing 104, and the output pinion 68 is coupled to the propeller shaft 72 via a universal joint 70 that is connected to the lower side. A first disconnecting device 24 is provided between the front wheel differential device 20 and the hypoid ring gear 66.

  The first disconnecting device 24 meshes with a mesh clutch mechanism 62 composed of a spline groove 58a formed on the outer periphery of the right end of the differential case shaft 58, a spline groove 60a formed on the outer periphery of the hypoid ring gear shaft 60, and the coupling sleeve 116. A shift rod 120 that fixes a shift fork 118 for operating the clutch mechanism 62 is provided. The shift rod 120 constitutes a hydraulic plunger at both ends, and is slidably incorporated in cylinders 122 and 124 formed in the housing 104. Yes.

  The coupling sleeve 116 is spline-coupled with the spline grooves 58a and 60a, and is movable between a connection position for connecting the differential case shaft 58 and the hypoid ring gear shaft 60 and a cutting position for releasing the connection. The coupling sleeve 116 can be slid by the tip end portion 118a slidably engaged with the groove portion 116a of the ring sleeve 116.

  FIG. 2 shows a state in which the first separation device 24 is cut in the two-wheel drive mode. The coupling sleeve 116 is not engaged with the spline groove 58a of the differential case shaft 58, and the differential case shaft 58 and the hypoid ring gear shaft are not engaged. It is in the cutting position which does not connect 60.

  In the four-wheel drive mode, the coupling sleeve 116 connects the differential case shaft 58 and the hypoid ring gear shaft 60 (illustrated by an imaginary line), and the first disconnecting device 24 is in a connected state. In this state, the driving force from the drive gear 36 engaged with the ring gear 38 can be transmitted to the propeller shaft 72 via the hypoid ring gear 66 and the output pinion 68.

  FIG. 3 is a cross-sectional view showing the rear wheel drive unit 18 and the rotation difference sensitive coupling 28 in FIG. 1, and the upper side of the figure is the front side (forward direction) of the four-wheel drive vehicle 12. In FIG. 3, the rotation difference sensitive coupling 28, the drive pinion 76, the rear wheel differential device 22 and the second disconnecting device 26 are accommodated in a housing 126. The housing 126 is divided into a plurality of parts, each of which is fastened with a bolt.

  In the present embodiment, an axial piston coupling is used as the rotation difference sensitive coupling 28. The axial piston coupling is provided with a rotor having a plurality of plunger pumps and orifices and a cam ring for driving the plunger pump on each of the input and output shafts, and utilizes the oil flow resistance when the rotor and the cam ring rotate relative to each other. Since the coupling is a well-known technique according to Patent Document 3 and the like, a detailed description of the configuration and operation of the rotation-difference type coupling 28 is omitted.

  The rear wheel differential 22 located on the lower left side of the housing 126 includes a hypoid ring gear 78 fixed to the flange portion 80a of the differential case 80, and a pinion 82 rotatably supported by a pinion shaft 128 fixed to the differential case 80. 84, a side gear 86 rotatably supported by the differential case 80 and connected to the left rear wheel drive shaft 90 in a non-rotatable manner, and a side gear 88 rotatably supported by the differential case 80 and connected to the side gear shaft 130 in a non-rotatable manner.

  The hypoid ring gear 78 is engaged with a drive pinion 76 connected to the rotation-sensitive coupling 28, and the side gears 86 and 88 are engaged with pinions 82 and 84, respectively. The differential case 80 is rotatably supported on the housing 126 by tapered roller bearings 132 and 134 on both the left rear wheel drive shaft 90 side and the side gear shaft 130 side, respectively.

  A second disconnecting device 26 is provided on the right side of the housing 126, and the second disconnecting device 26 is provided on the right end surface portion of the side gear shaft 130, the claw portion 130 b formed on the flange portion, and the left end of the clutch shaft 136. The formed hub portion 136a, baux ring 138, insert key 140, clutch sleeve 142, shift fork 144, shift rod 146, pinion 148, and servo motor (not shown) are configured.

  The synchro cone 130a constitutes a conical friction clutch mechanism with a friction surface on the outer peripheral portion and a friction surface on the left inner side of the boke ring 138. The clutch shaft 136 has a roller bearing 150 on the left end side and a ball bearing 152 on the right end side. Each is supported rotatably by the side gear shaft 130 and the housing 126, and the right rear wheel drive shaft 92 is non-rotatably connected to the right side.

  The hub portion 136a is energized by the spring 154 in the outer radial direction and accommodates a plurality of insert keys 140 that are movable in the axial direction of the clutch shaft 136 in the outer peripheral portion, and rotates together with the right rear wheel drive shaft 92.

  The clutch sleeve 142 is splined to the outer periphery of the hub portion 136a and rotates together with the clutch shaft 136. The claw portion 142b engages with the claw portion 130b of the side gear shaft 130 to connect the side gear shaft 130 and the right rear wheel drive shaft 92. The shift fork 144 can move between the connection position and the cutting position where the engagement is released and the connection is released, and the shift fork 144 slides the clutch sleeve 142 by the tip end portion 144a slidably engaged with the groove portion 142a of the clutch sleeve 142. Can do.

  The bake ring 138 is splined to the inner periphery of the clutch sleeve 142 and rotates together with the clutch sleeve 142, and can move between a synchronous position where the friction surface is pressed against the friction surface of the synchro cone 136a and an asynchronous position where the friction surface is not pressed. It is pressed by the insert key 140 interlocked with the sliding of the clutch sleeve 142 and generates friction torque on both friction surfaces.

  The shift fork 144 is fixed to the shift rod 146, and the shift rod 146 forms a rack 146 a that engages with a pinion 148 driven by a servo motor (corresponding to the actuator 98 in FIG. 1). The shaft holes 156 and 158 provided are slidably incorporated.

  FIG. 3 shows a state where the second disconnecting device 26 is connected in the four-wheel drive mode. The clutch sleeve 142 is in a state where the claw portion 142b and the claw portion 130b of the side gear shaft 130 are engaged with each other. And the right rear wheel drive shaft 92 are connected to each other. In this state, the driving force from the drive pinion 76 engaged with the hypoid ring gear 78 can be transmitted to the left rear wheel 100 and the right rear wheel 102 via the left rear wheel drive shaft 90 and the right rear wheel drive shaft 92. .

  In the two-wheel drive mode, the shift fork 144 and the shift rod 146 move rightward to disengage the claw portion 142b and the claw portion 130b (illustrated by imaginary lines), and the clutch sleeve 142 and the side gear shaft 130 are connected. First, the second disconnecting device 26 is in a disconnected state.

  In the present embodiment, the engagement clutch mechanism 62 of the first disconnecting device 24 shown in FIG. 2 uses a spline clutch system, and the engagement clutch mechanism 96 of the second disconnecting device 26 shown in FIG. 3 uses a dog clutch system. Any clutch system can be used for both the first disconnecting device 24 and the second disconnecting device 26, and other systems may be used. Further, the synchronization mechanism of the second separating device 26 uses a conical friction clutch system, but other systems may be used.

  In the present embodiment, the shift rod 120 shown in FIG. 2 operates in the direction indicated by the arrow by applying hydraulic pressure to the cylinder 122 or the cylinder 124, and the shift rod 146 shown in FIG. 3 engages with the rack 146a. The pinion 148 is driven by the servo motor and rotates to operate in the direction indicated by the arrow. However, the actuator for driving the shift rods 120 and 146 can be of any type, and the hydraulic cylinder and servo in this embodiment can be used. A system other than the motor may be used.

  Furthermore, in this embodiment, an axial piston coupling is used as the rotation difference sensitive coupling 28. However, if the rotation difference sensitive type is used, another type of coupling, for example, a viscous coupling or Patent Document 4 is used. It is possible to use a rotary blade coupling or the like that is well known.

  Here, the function of the driving force transmission device 10 in the two-wheel drive mode and the four-wheel drive mode of the first embodiment will be described with reference to FIG.

  In the two-wheel drive mode, the first separation device 24 is disconnected by the control signal E1 of the ECU 30. Therefore, the driving force from the transmission 34 is transmitted to the differential case shaft 58 via the ring gear 38 and the differential case 40 of the front wheel differential device 20, but since the first disconnecting device 24 is in the disconnected state, the hypoid ring gear shaft. 60 is not output.

  On the other hand, since the second disconnecting device 26 is also disconnected by the control signal E2 from the ECU 30, the hypoid ring gear 78 of the rear wheel differential 22 is maintained even when the left rear wheel 100 and the right rear wheel 102 are rotating. Does not rotate.

  Thus, in the two-wheel drive mode, the hypoid ring gear 66, the output pinion 68, the universal joint 70, the propeller shaft 72, the universal joint 74, the rotation difference sensitive coupling 28, the drive pinion 76, and the rear wheel differential 22 The problem that the fuel consumption decreases due to friction loss caused by the rotation of the driving force transmission unit 16 in the two-wheel drive mode due to the rotation of the driving force transmission unit 16 including the hypoid ring gear 78 being stopped can be solved.

  More specifically, in the configuration in which only the first disconnecting device 24 is provided as a PTU (Power Take-off Unit), that is, in the configuration in which the second disconnecting device 26 does not exist in FIG. If the side gear 88 of the rear wheel differential 22 and the right rear wheel drive shaft 92 are connected, for example, when the side gears 86 and 88 rotate in the same direction and at the same speed, the pinions 82 and 84 do not rotate (spin). Further, the differential case 80 and the hypoid ring gear 78 supporting the pinions 82 and 84 rotate.

  Further, even if there is a difference in rotation speed between the side gears 86 and 88, if the rotation is in the same direction, the rotation speed changes, but the differential case 80 and the hypoid ring gear 78 rotate. When the hypoid ring gear 78 rotates in this manner, the drive pinion 76, the rotation-sensitive coupling 28, the universal joint 74, the propeller shaft 72, the universal joint 70, the output pinion 68, and the hypoid ring gear 66 rotate.

  Although the driving force transmission portion 16 from the hypoid ring gear 66 to the hypoid ring gear 78 is a portion that does not need to rotate in the two-wheel drive mode, this portion rotates, so that the oil viscosity resistance and This causes a friction loss of the bearing portion, resulting in a loss of driving force and a reduction in fuel consumption.

  Therefore, in the present embodiment, by providing the second disconnecting device 26 in addition to the first disconnecting device 24, the first disconnecting device 24 and the second disconnecting device 26 are disconnected from the engine 32 in the two-wheel drive mode. The transmission of the driving force and the driving force from the rear wheels 100 and 102 is cut off, and the rotation of the driving force transmitting portion 16 from the hypoid ring gear 66 to the hypoid ring gear 78 is prevented.

  That is, when the second separating device 26 is disconnected and the connection between the side gear 88 and the right rear wheel drive shaft 92 is disconnected, the rotation of the right rear wheel 102 is not transmitted to the side gear 88, and therefore the side gear 86 by the left rear wheel 100. This rotates the side gear 88 in the opposite direction via the pinions 82 and 84. At this time, since the rotational resistance of the driving force transmission unit 16 connected to the hypoid ring gear 78 is larger than the rotational resistance of the side gear 88, the hypoid ring gear 78 does not rotate.

  In the four-wheel drive mode, the first disconnecting device 24 is connected, so that the driving force from the transmission 34 is connected to the first disconnecting device in the connected state from the ring gear 38 and the differential case 40 of the front wheel differential 20. 24, the hypoid ring gear 66 is rotated and the direction is changed by the output pinion 68, and then transmitted to the universal joint 70, the propeller shaft 72, and the universal joint 74, and is input to the rotation difference sensitive coupling 28.

  When there is a difference in rotational speed between the front wheels 54 and 56 and the rear wheels 100 and 102, the rotational difference sensitive coupling 28 applies a driving force corresponding to the rotational speed difference to the hypoid of the rear wheel differential device 22 via the drive pinion 76. Output to the ring gear 78. The rear wheel differential device 22 operates effectively when the second disconnecting device 26 is connected, and can transmit the driving force to the left rear wheel 100 and the right rear wheel 102 for rotation.

  Of course, in both the two-wheel drive mode and the four-wheel drive mode, the driving force from the drive gear 36 of the transmission 34 is transmitted to the left front wheel drive shaft 50 and the right front wheel drive shaft 52 via the front wheel differential device 20. The left front wheel 54 and the right front wheel 56 are rotated.

  Next, switching control from the two-wheel drive mode to the four-wheel drive mode and from the four-wheel drive mode to the two-wheel drive mode in the first embodiment will be described with reference to FIG.

  In the two-wheel drive mode, since the first separating device 24 is disconnected, the driving force from the engine 32 is not transmitted to the rear wheel differential device 22, and the second separating device 26 is also disconnected. Therefore, in the rear wheel differential 22, the side gear 86 is rotated by the left rear wheel 100, and the side gear 88 idles in the opposite direction to the side gear 86 via the pinions 82 and 84.

  When switching from the two-wheel drive mode to the four-wheel drive mode, first, the actuator 98 is driven by the control signal E2 of the ECU 30, and the second separating device 26 is synchronized, that is, the side gear shaft 130 and the right rear wheel drive shaft having different rotational directions. 92 synchronization is started. Next, the actuator 64 is driven by the control signal E1 of the ECU 30 when the rotational speeds of the hypoid ring gear shaft 60 and the differential case shaft 58 of the first separating device 24 coincide with each other or when the rotational speed difference decreases to a predetermined range. Then, the first disconnecting device 20 is connected.

  More specifically, in FIG. 3, the pinion 148 is rotated by the servo motor, and the shift rod 146 and the shift fork 144 are moved to the left (in the direction of the rear wheel differential device 22) via the rack 146a engaged with the pinion 148. Moving.

  When the tooth 144a of the shift fork 144 engaged with the groove 142a moves the clutch sleeve 142 to the left, the baux ring 138 also moves to the left via the insert key 140 engaged with the clutch sleeve 142. Then, the friction surface of the baux ring 138 and the friction surface of the synchro cone 130a come into contact with each other.

  Due to the friction torque generated by both friction surfaces, the driving force of the right rear wheel 102 via the right rear wheel drive shaft 92 is gradually transmitted to the side gear shaft 130 to start synchronization, and the rotation direction of the side gear shaft 130 is changed to the right rear. The hypoid ring gear 78 starts rotating by reversing in the same direction as the wheel drive shaft 92.

  In FIG. 1, the driving force from the left rear wheel 100 and the right rear wheel 102 is transmitted from the hypoid ring gear 78 to the drive pinion 76, and the universal joint 74, the propeller shaft 72, and the free through the rotation-sensitive coupling 28. The joint 70, the output pinion 68, and the hypoid ring gear 66 are rotated. That is, when the synchronization of the second separating device 26 is started, the rotational speed of the driving force transmission unit 16 increases, and the rotational speed difference between the hypoid ring gear shaft 60 and the differential case shaft 58 begins to decrease.

  When the synchronization of the second separating device 26 is completed, the gear ratio between the front and rear wheels is such that the rotational speed of the hypoid ring gear shaft 60 exceeds the rotational speed of the opposing differential case shaft 58 and the direction of the rotational speed difference is reversed. Therefore, when the rotation speed of the bell gear shaft 60 coincides with the rotation speed of the opposing differential case shaft 58 between the start and completion of the synchronization of the second separating device 26, or the rotation speed difference is within a predetermined range. The actuator 64 is driven by the control signal E1 of the ECU 30.

  In FIG. 2, hydraulic pressure is applied to the cylinder 124 by the control signal E1 of the ECU 30, the shift rod 120 moves to the left (in the direction of the front wheel differential device 20), and the shift fork 118 fixed to the shift rod 120 moves to the left. To do. The tooth portion 1118a of the shift fork 118 engaged with the groove portion 116a moves the coupling sleeve 116 to the left, the coupling sleeve 116 meshes with the spline groove 58a of the differential case shaft 58, and the first separating device 24 is connected. Is done.

  In FIG. 3, when the synchronization of the second disconnecting device 26 is completed, the relative speed between the claw portion 142b of the clutch sleeve 142 and the claw portion 130b of the side gear shaft 130 becomes zero, and the clutch sleeve 142 moves further to the left, The portion 142b and the claw portion 130b can be engaged with each other.

  When the synchronization of the second separating device 26 is completed and the movement of the baux ring 138 is stopped, the clutch sleeve 142 pushes over the insert key 140 against the spring 154, moves further to the left, and the claw portion 142b moves to the side gear. By engaging with the claw portion 130b of the shaft 130, the second disconnecting device 26 is connected.

  In FIG. 1, after the first disconnecting device 24 is connected, when the synchronization is completed and the second disconnecting device 26 is also connected, the driving force from the engine 32 is the front wheel driving unit 14, the driving force transmitting unit 16, Transmission to the left rear wheel 100 and the right rear wheel 102 via the rear wheel drive unit 18 is possible, and the rotation difference sensitive coupling 28 passively controls the transmission torque between the front and rear wheels in accordance with the running state. It becomes a mode.

  At the time of switching from the four-wheel drive mode to the two-wheel drive mode, first, the ECU 30 controls the engine 32 so that coast torque (torque from the rear wheel side) acts on the first disconnecting device 24, and then the ECU 30 When the actuator 98 is driven by the control signal E2 to start cutting the second disconnecting device 26, and then the direction of the torque acting on the first disconnecting device 24 changes, that is, from the coast torque to the drive torque (from the engine side). At the timing when the torque becomes zero, the actuator 64 is driven by the control signal E1 of the ECU 30, and the first disconnecting device 24 is disconnected.

  Here, since the driving force transmission unit 16 has a gear ratio such that the rear wheel side rotates at a higher speed than the front wheel side, the driving force from the engine 32 in the case of repulsive driving in the four-wheel driving mode or the like. In a state in which is not added, coast torque acts on the first separating device 24.

  In FIG. 3, the servo motor rotates the pinion 148 by the control signal E <b> 2 of the ECU 30, and the shift rod 146 and the shift fork 144 move to the right through the rack 146 a that engages with the pinion 148.

  When the tooth portion 144a of the shift fork 144 engaged with the groove portion 142a moves the clutch sleeve 142 to the right, the engagement between the claw portion 142b and the claw portion 130b of the side gear shaft 130 is released, The pressing of the friction surface and the friction surface of the synchro cone 130a is also released, and the second separation device 26 is cut.

  In FIG. 2, when the coasting torque via the driving force transmitting portion 16 decreases and the direction of the torque acting on the first disconnecting device 24 changes, that is, when changing from the coasting torque to the driving torque, the coupling sleeve When the torque acting on 116 approaches zero and the torque generated between the coupling sleeve 116 and the spline grooves 58a, 60a decreases, the control signal E1 of the ECU 30 applies the shift rod 120 to the cylinder 122 in addition to the hydraulic pressure. The coupling sleeve 116 is moved to the right (in the direction of the hypoid ring gear 66), and the coupling sleeve 116 is moved to the right, and the first disconnecting device 24 is cut.

  In FIG. 3, when the shift rod 146 and the shift fork 144 move further to the right, and the contact between the friction surface of the boke ring 138 and the friction surface of the synchro cone 130a is completely released, the second separation device 26 is cut. It becomes a state.

  In FIG. 1, when the first disconnecting device 24 and the second disconnecting device 26 are disconnected, the driving force from the engine 32 and the driving force from the left rear wheel 100 and the right rear wheel 102 are transmitted to the driving force transmitting unit 16. Therefore, since the driving force transmission unit 16 does not rotate, the two-wheel drive mode is achieved in which fuel consumption is prevented from being reduced due to friction loss.

  FIG. 4 is an explanatory view showing a second embodiment of the driving force transmission device for a four-wheel drive vehicle according to the present invention, which is applied to an FF vehicle-based four-wheel drive vehicle. This embodiment is different from the first embodiment shown in FIG. 1 in that the synchronization mechanism is provided in the first disconnecting device instead of the second disconnecting device, and a viscous coupling is used for the rotation-sensitive coupling. Since the configuration is substantially the same, only the portions different from FIG. 1 will be described.

  In FIG. 4, the driving force transmission device 210 of the present embodiment is provided in a four-wheel drive vehicle 212, and includes a front wheel driving unit (first driving unit) 214, a driving force transmission unit 216, and a rear wheel driving unit (second driving unit). 218, a front wheel drive unit 214 is provided with a front wheel differential device 220, a driving force transmission unit 216 is provided with a rotation difference sensitive coupling 228, and a rear wheel drive unit 218 is provided with a rear wheel differential device 222. Further, a first disconnecting device 224 is provided between the front wheel differential device 220 and the driving force transmission unit 216, and a second disconnecting device 226 is provided between the rear wheel differential device 222 and the right rear wheel 302.

  In the present embodiment, a meshing clutch mechanism 262 having a synchronization mechanism 294 is used as the first disconnecting device 224, and a meshing clutch mechanism 296 is used as the second disconnecting device 226. The actuators 264 and 298 are driven to drive 2 It is possible to switch between a disconnected state in the wheel drive mode and a connected state in the four wheel drive mode.

  The first separation device 224 is substantially the same as the first separation device 24 of the first embodiment except that a synchronization mechanism 294 is provided, and has the same configuration as the second separation device 26 shown in FIG. Therefore, detailed description is omitted (see FIGS. 2 and 3).

  FIG. 5 is a cross-sectional view showing the rear wheel drive unit 218 and the rotation-sensitive coupling 228 in FIG. 4, and the upper side of the figure is the front side (forward direction) of the four-wheel drive vehicle 212. In FIG. 5, a rotation difference sensitive coupling 228, a drive pinion 276, a rear wheel differential device 222 and a second separating device 226 are accommodated in a housing 306.

  In FIG. 5, the rear wheel drive unit 218 is substantially the same except that the second separation device 226 removes the synchronization mechanism from the second separation device 26 of the first embodiment (FIG. 3). Detailed description is omitted.

  Further, the rotational difference sensitive coupling 228 is different from the rotational differential sensitive coupling 28 of the first embodiment in that an axial piston coupling is used but a viscous coupling is used.

  Viscous coupling is a well-known technique as a fluid clutch that utilizes the shear resistance of oil when a plurality of clutch plates provided on each of the input and output shafts rotate relative to each other in a case filled with oil. Since this is the same as the axial piston coupling of the first embodiment, a detailed description of the rotation difference sensitive coupling 228 is also omitted.

  FIG. 6 is an explanatory view showing a third embodiment of the driving force transmission device for a four-wheel drive vehicle according to the present invention, which is applied to a four-wheel drive vehicle based on an FF vehicle. This embodiment is substantially the same as the second embodiment shown in FIG. 4 except that a second separating device is provided on both sides of the rear wheel differential and a rotary blade coupling is used as a rotation-sensitive coupling. Therefore, only the parts different from FIG. 4 will be described.

  In FIG. 6, the driving force transmission device 310 of the present embodiment is provided in a four-wheel drive vehicle 312 and includes a front wheel driving unit (first driving unit) 314, a driving force transmission unit 316, and a rear wheel driving unit (second driving unit). 318, a front wheel drive unit 314 is provided with a front wheel differential device 320, a driving force transmission unit 316 is provided with a rotation differential type coupling 328, and a rear wheel drive unit 318 is provided with a rear wheel differential device 322.

  Further, a first disconnecting device 324 is provided between the front wheel differential device 320 and the driving force transmission unit 316, and a second disconnecting device 326 is provided between the rear wheel differential device 322 and the left rear wheel 400, and the rear wheel differential. A second disconnecting device 327 is provided between the device 322 and the right rear wheel 402, and the ECU 330 controls the actuator 364 of the first disconnecting device 324 and the actuators 398 and 399 of the second disconnecting devices 326 and 327. Signals E3, E4, E5 are provided.

  In FIG. 4, since the second separating device 226 is installed only between the rear wheel differential device 222 and the right rear wheel 302, the second separating device 226 is disconnected in the two-wheel drive mode, and the rear wheel differential. Even when the hypoid ring gear 278 of the moving device 222 is not rotating, the rotation of the left rear wheel 300 causes the inside of the rear wheel differential device 222, that is, the side gear 286, the pinions 282, 284, and the side gear 288 to rotate. In other words, the friction loss at this portion causes a reduction in fuel consumption.

  On the other hand, in FIG. 6, when the second separation devices 326 and 327 are disconnected in the two-wheel drive mode, the rotation of the left rear wheel 400 and the right rear wheel 402 is not transmitted to the rear wheel differential device 322 at all. All elements of the rear wheel differential 322, that is, the hypoid ring gear 378, the differential case 380, the pinions 382 and 384, and the side gears 386 and 388 do not rotate. Therefore, the third embodiment shown in FIG. 6 can further prevent the fuel consumption from lowering than the second embodiment shown in FIG.

  Switching control from the two-wheel drive mode to the four-wheel drive mode and from the four-wheel drive mode to the two-wheel drive mode in the third embodiment will be described with reference to FIG.

  In the two-wheel drive mode, since the first disconnecting device 324 is disconnected, the driving force from the engine 332 is not transmitted to the rear wheel differential device 322, and the second disconnecting devices 326 and 327 are also disconnected. Therefore, the driving force from the left rear wheel 400 and the right rear wheel 402 is not transmitted to the rear wheel differential device 322. Therefore, in the two-wheel drive mode, the rear wheel differential 322 does not rotate at all.

  When switching from the two-wheel drive mode to the four-wheel drive mode, first, the actuator 364 is driven by the control signal E3 of the ECU 330 to synchronize the first disconnecting device 324, that is, the rotating differential case shaft 358 and the non-rotating hypoid. Synchronization with the ring gear shaft 360 is started.

  The driving force from the drive gear 336 rotates the rear wheel differential device 322 via the rotation difference sensitive coupling 328, and therefore the side gears 386 and 388 stopped because the rear wheel differential device 322 does not rotate. It starts to rotate. That is, when the synchronization of the first disconnecting device 324 starts, the rotational speed of the driving force transmission unit 316 increases, the rotational speed difference between the side gear shaft 404 and the left rear wheel drive shaft 390, the side gear shaft 406 and the right rear wheel drive. The rotational speed difference from the shaft 392 begins to decrease.

  When the synchronization of the first separating device 324 is completed, the rotational speeds of the side gear shafts 404 and 406 exceed the rotational speeds of the opposing left rear wheel drive shaft 390 and right rear wheel drive shaft 392, respectively, and the direction of the rotational speed difference Since the gear ratio between the front and rear wheels is configured to reverse, the left rear wheel drive shaft in which the rotational speeds of the side gear shafts 404 and 406 are opposed from the start to the completion of the synchronization of the first disconnecting device 324. 390, when the rotational speed of the right rear wheel drive shaft 392 matches the rotational speed, or when the rotational speed difference is within a predetermined range, the actuators 398 and 399 are driven by the control signals E4 and E5 of the ECU 330, and the second disconnecting device 326, 327 is connected.

  When the synchronization is completed after the second disconnecting devices 326 and 327 are connected and the first disconnecting device 324 is also connected, the driving force from the engine 332 is transmitted to the driving force transmitting unit 316 and the rotation difference sensitive coupling 328. The transmission can be transmitted to the left rear wheel 400 and the right rear wheel 402 via the rear wheel differential device 322, and the rotation difference sensitive coupling 328 becomes a four-wheel drive mode in which the transmission torque is passively controlled according to the traveling state. .

  When switching from the four-wheel drive mode to the two-wheel drive mode, the engine 332 is first controlled by the ECU 330 so that the drive torque acts on the second disconnecting devices 326 and 327, and then the actuator 364 is received by the control signal E3 of the ECU 330. To start cutting of the first disconnecting device 324, and then the torque is zero when the direction of the torque acting on the second disconnecting device 326, 327 changes, that is, when the drive torque changes to the coast torque. At the timing, the actuators 398 and 399 are driven by the control signals E4 and E5 of the ECU 330, and the second disconnecting device 326 is disconnected.

  When the first separation device 324 and the second separation devices 326 and 327 are disconnected, the driving force from the engine 332 and the driving force from the left rear wheel 400 and the right rear wheel 402 are not transmitted to the driving force transmission unit 316. Since the driving force transmission unit 316 does not rotate, the two-wheel drive mode is achieved in which a reduction in fuel consumption due to friction loss is prevented.

  FIG. 7 is an explanatory view showing a fourth embodiment of the driving force transmission device for a four-wheel drive vehicle according to the present invention, which is applied to a four-wheel drive vehicle based on an FF vehicle. In this embodiment, in contrast to the third embodiment shown in FIG. 6, the rotation-sensitive coupling provided on both sides of the hypoid ring gear replaces the function of the rear wheel differential device instead of the rear wheel differential device. Since the configuration is substantially the same except that the rotational difference sensitive coupling is arranged on the rear wheel drive shaft, only the parts different from FIG. 6 will be described.

  In FIG. 7, the driving force transmission device 410 of this embodiment is provided in a four-wheel drive vehicle 412, and includes a front wheel driving unit (first driving unit) 414, a driving force transmission unit 416, and a rear wheel driving unit (second driving unit). 418, the front wheel drive unit 414 is provided with a front wheel differential device 420, and the rear wheel drive unit 418 is provided with rotational difference sensitive couplings 428, 429.

  In addition, a first separation device 424 is provided between the front wheel differential device 420 and the driving force transmission unit 416, and a second separation device 426 is provided between the rotation difference sensitive coupling 428 and the left rear wheel 500, and the rotation difference sensitivity. A second decoupling device 427 is provided between the mold coupling 429 and the right rear wheel 502.

  The left rear wheel drive shaft 490 and the right rear wheel drive shaft 492 connecting the left rear wheel 500 and the right rear wheel 502 serve as the output shaft of the rear wheel drive unit 418. That is, the rotation-sensitive couplings 428 and 429 are disposed coaxially with the output shaft of the rear wheel drive unit 418.

  In the four-wheel drive mode, since the first disconnecting device 424 and the second disconnecting devices 426 and 427 are connected, the driving force from the engine 432 is the driving force transmitting unit 416, the hypoid ring gear 478, the rotation difference sensitive type. The torque is transmitted to the left rear wheel 500 and the right rear wheel 502 via the couplings 428 and 429, and the rotation difference sensitive couplings 428 and 429 passively control the transmission torque in accordance with the traveling state.

  In the two-wheel drive mode, since the first disconnecting device 424 is disconnected, the driving force from the engine 432 is not transmitted to the rotation-sensitive couplings 428 and 429, and the second disconnecting devices 426 and 427 are also used. Since it is cut, the driving force from the left rear wheel 500 and the right rear wheel 502 is not transmitted to the rotation difference sensitive couplings 428 and 429.

  Accordingly, in the two-wheel drive mode, the driving force transmission unit 416, the hypoid ring gear 478, and the rotation difference sensitive couplings 428 and 429 do not rotate at all. Therefore, the fourth embodiment shown in FIG. 7 can prevent the fuel consumption from being further reduced as compared with the second embodiment shown in FIG. 4, similarly to the third embodiment shown in FIG. 6.

  Further, in the present embodiment, an LSD (Limited Slip Differential) function is also provided by the rotation difference sensitive couplings 428 and 429, and the motion performance as a four-wheel drive vehicle is improved.

  FIG. 8 is an explanatory view showing a fifth embodiment of a driving force transmission device for a four-wheel drive vehicle according to the present invention, which is applied to a four-wheel drive vehicle based on an FF vehicle. This embodiment is different from the fourth embodiment shown in FIG. 7 except that the position of the rotation difference-sensitive coupling and the second disconnecting device are switched, and an axial piston coupling is used as the rotation difference-sensitive coupling. Since the configuration is substantially the same, only the differences from FIG. 7 will be described.

  In FIG. 8, a driving force transmission device 510 according to this embodiment is provided in a four-wheel drive vehicle 512, and includes a front wheel drive unit (first drive unit) 514, a drive force transmission unit 516, and a rear wheel drive unit (second drive unit). 518, the front wheel drive unit 514 is provided with a front wheel differential 520, and the rear wheel drive unit 518 is provided with rotational difference sensitive couplings 528 and 529.

  Further, a first disconnecting device 524 is provided between the front wheel differential device 520 and the driving force transmission unit 516, and a second disconnecting device 526 is provided between the hypoid ring gear 578 and the rotation difference sensitive couplings 528 and 529, respectively. 527 is provided.

  In the four-wheel drive mode, since the first disconnecting device 524 and the second disconnecting devices 526 and 527 are connected, the driving force from the engine 532 is the driving force transmitting unit 516, the hypoid ring gear 578, and the rotation difference sensitive type. The torque is transmitted to the left rear wheel 600 and the right rear wheel 602 via the couplings 528 and 529, and the rotation difference sensitive couplings 528 and 529 passively control the transmission torque according to the traveling state.

  In the two-wheel drive mode, since the first disconnecting device 524 is disconnected, the driving force from the engine 532 is not transmitted to the driving force transmitting portion 516 and the hypoid ring gear 578, and the second disconnecting device 526 is used. Since 527 is also cut, the driving force from the left rear wheel 600 and the right rear wheel 602 is not transmitted to the driving force transmission unit 516 and the hypoid ring gear 578. Accordingly, in the two-wheel drive mode, the driving force transmission unit 516 and the hypoid ring gear 578 do not rotate at all.

  Also in this embodiment, the LSD function is provided by the rotation-difference-sensitive couplings 528 and 529, and the motion performance as a four-wheel drive vehicle is improved.

  In the present embodiment, the second separating devices 526 and 527 are arranged on both sides of the hypoid ring gear 578. However, the second separating devices 526 and 527 are arranged on one side of the hypoid ring gear 578, that is, the second separating devices 526 and 527 are arranged. Only one of the configurations may be used.

  FIG. 9 is an explanatory view showing a sixth embodiment of the driving force transmission device for a four-wheel drive vehicle according to the present invention, which is applied to an FR vehicle-based four-wheel drive vehicle.

  In FIG. 9, the driving force transmission device 610 of the present embodiment is provided in a four-wheel drive vehicle 612, and includes a front wheel drive unit (second drive unit) 614, a drive force transmission unit 616, and a rear wheel drive unit (first drive unit). 618, a front wheel drive unit 614 is provided with a front wheel differential device 620, a driving force transmission unit 616 is provided with a rotation differential type coupling 628, and a rear wheel drive unit 618 is provided with a rear wheel differential device 622. Further, a first disconnecting device 624 is provided between the driving force transmission unit 616 and the rear wheel driving unit 618, and a second disconnecting device 626 is provided between the front wheel differential device 620 and the right front wheel 656.

  Control signals E6 and E7 from the ECU 630 are given to the actuator 664 of the first disconnecting device 624 and the actuator 698 of the second disconnecting device 626. The driving force from the engine 632 is shifted by the transmission 634 and then transmitted from the output shaft 668 to the rear wheel differential 622 via the universal joint 670, the propeller shaft 672, the universal joint 674, and the drive pinion 676.

  The rear wheel differential 622 includes a hypoid ring gear 678 that engages with a drive pinion 676, a differential case 680 to which the hypoid ring gear 678 is fixed, pinions 682 and 684 that are rotatably supported in the differential case 680, and a pinion 682 and 684 are engaged with the side gears 686 and 688, and the driving force from the drive pinion 676 is received by the hypoid ring gear 678, and the left rear wheel drive shaft 690 and the right side through the pinion 682 and 684 and the side gears 686 and 688. The rear wheel drive shaft 692 is driven, and the left rear wheel 700 and the right rear wheel 702 are rotated to transmit the driving force to the road surface.

  The rear wheel differential device 622 absorbs the rotation speed and generates the left rear wheel 700 and the right rear wheel 702 when a difference in rotation speed is generated between the left rear wheel 700 and the right rear wheel 702 due to changes in cornering or road surface conditions. Rotate with a torque equal to.

  In the two-wheel drive mode, the first disconnecting device 624 is in a state where the actuator 664 is driven by the control signal E6 from the ECU 630, the driving force transmitting unit 616 is disconnected, and the driving force for the front wheel side is disconnected. Therefore, in the two-wheel drive mode, the driving force from the engine 632 is not transmitted to the front wheel side via the driving force transmission unit 616.

  On the other hand, in the case of the four-wheel drive mode, the first separation device 624 is connected to the driving force transmission unit 616 by driving the actuator 664 by the control signal E6 from the ECU 630. Therefore, the driving force of the output shaft 668 is output to the sprocket shaft 658, and is transmitted to the drive pinion 709 via the sprocket 704, the chain belt 706, the sprocket 708, and the rotation difference sensitive coupling 628 that rotate integrally with the sprocket shaft 658. The direction is changed from the drive pinion 709 to the hypoid ring gear 638 of the front wheel differential 620 and transmitted.

  In this embodiment, an axial piston coupling is used as the rotation-difference-sensitive coupling 628, and there is no difference in rotational speed between the front wheels 654 and 656 and the rear wheels 700 and 702 in the four-wheel drive mode. The rotation difference sensitive coupling 628 does not distribute the driving force to the front wheel drive unit 614.

  However, in the four-wheel drive mode, when there is a difference in the rotational speed between the front wheels 654 and 656 and the rear wheels 700 and 702, such as when any wheel slips, that is, the rotation-sensitive coupling 628 is driven. When a rotational speed difference occurs between the force transmission unit 616 side and the front wheel drive unit 614 side that is opposite to the force transmission unit 616 side, the rotation difference sensitive coupling 628 applies a driving force according to the rotational speed difference to the front wheel drive unit 614. To distribute.

  The front wheel differential 620 includes a hypoid ring gear 638 that engages with the drive pinion 709, a differential case 640 to which the hypoid ring gear 638 is fixed, pinions 642 and 644 and a pinion 642 that are rotatably supported inside the differential case 640. The left front wheel 654 and the right front wheel drive shaft 650 are connected to the side gear 646, and the second front disconnecting device 626 and the right front wheel drive shaft 652 are connected to the side gear 648. The front wheel 656 is rotated to transmit the driving force to the road surface.

  In the present embodiment, the second disconnecting device 626 is provided in the middle of the right front wheel drive shaft 652 that connects the front wheel differential 620 and the right front wheel 656, and switches connection and disconnection of the driving force to the right front wheel 656. The position of the two separating device 626 is not limited to this, and may be provided in the middle of the left front wheel drive shaft 650 or inside the front wheel differential device 620.

  In the two-wheel drive mode, the second separation device 626 controls the actuator 698 to be disconnected by a control signal E7 from the ECU 630, and disconnects the transmission of the driving force between the right front wheel 656 and the front wheel differential device 620. In the four-wheel drive mode, the actuator 698 is driven by the control signal E7 from the ECU 630 to control the connection state, and the driving force from the engine 632 via the rotation-sensitive coupling 628 and the front wheel differential 620 is applied. This is transmitted to the right front wheel 656.

  That is, in the four-wheel drive mode, the front wheel differential 620 operates effectively, and even if there is a difference in rotational speed between the left front wheel 654 and the right front wheel 656 due to changes in cornering or road conditions, the front wheel differential 620 The rotational speed difference can be absorbed and the left front wheel 654 and the right front wheel 656 can be rotated by applying equal torque.

  In this embodiment, a meshing clutch mechanism 662 having a synchronization mechanism 660 is used as the first disconnecting device 624, and a meshing clutch mechanism 696 having a synchronizing mechanism 694 is used as the second disconnecting device 626, and the actuators 664 and 698 are used. It is possible to switch between a disconnected state in the two-wheel drive mode and a connected state in the four-wheel drive mode by driving.

  The first detaching device 624 is substantially the same as the first detaching device 224 of the second embodiment shown in FIG. 4, and the second detaching device 426 is substantially the same as the second detaching device 26 shown in FIG. Since the configuration is the same, a detailed description is omitted.

  Here, the function of the driving force transmission device 610 in the two-wheel drive mode and the four-wheel drive mode of the fourth embodiment will be described with reference to FIG.

  In the two-wheel drive mode, the first disconnecting device 624 is disconnected by the control signal E6 of the ECU 630. For this reason, the driving force from the transmission 634 is not output to the sprocket shaft 658.

  On the other hand, since the second disconnecting device 626 is also disconnected by the control signal E7 from the ECU 630, the hypoid ring gear 638 of the front wheel differential 620 does not rotate even if the left front wheel 654 and the right front wheel 656 are rotating.

  Accordingly, in the two-wheel drive mode, the driving force transmission unit 616 including the sprocket 704, the chain belt 706, the sprocket 708, the rotation difference sensitive coupling 628, the drive pinion 709, and the hypoid ring gear 638 of the front wheel differential 620. The problem that the fuel consumption is reduced due to friction loss due to the rotation being stopped and the driving force transmission unit 616 rotating in the two-wheel drive mode can be solved.

  In the four-wheel drive mode, the first disconnecting device 624 is connected, so that the driving force from the transmission 634 is connected to the sprocket 704 and the chain belt 706 via the first disconnecting device 624 connected from the output shaft 668. , Transmitted to the sprocket 708 and input to the rotation difference sensitive coupling 628.

  When there is a difference in rotational speed between the front wheels 654 and 656 and the rear wheels 700 and 702, the rotational difference sensitive coupling 628 generates a driving force corresponding to the rotational speed difference through a drive pinion 709 and a hypoid ring of the front wheel differential device 620. Output to gear 638. The front wheel differential device 620 operates effectively when the second disconnecting device 626 is connected, and can transmit the driving force to the left front wheel 654 and the right front wheel 656 for rotation.

  Of course, in both the two-wheel drive mode and the four-wheel drive mode, the driving force from the output shaft 668 of the transmission 634 is transmitted via the rear wheel differential 622 to the left rear wheel drive shaft 690 and the right rear wheel drive shaft 692. The left rear wheel 700 and the right rear wheel 702 can be rotated.

  In the sixth embodiment, since the first disconnecting device 624 and the second disconnecting device 626 are respectively provided with the synchronization mechanisms 660 and 694, both of them are as in the first to third embodiments shown in FIGS. 1-6. There is no need to provide a time difference in the operation timing of the disconnecting device, and the first disconnecting device 624 and the first disconnecting device 624 are the same in any of the switching from the two-wheel driving mode to the four-wheel driving mode. The two-separation device 626 can be operated at the same time, so that mode switching can be performed more quickly than in the first to third embodiments.

Although the description of the embodiment is finished as described above, the present invention is not limited to the above-described embodiment, includes appropriate modifications without impairing the object and advantages thereof, and is further limited by numerical values shown in the above-described embodiment. I do not receive it.

10, 210, 310, 410, 510, 610: Driving force transmission devices 12, 212, 312, 412, 512, 612: Four-wheel drive vehicles 14, 214, 314, 414, 514, 614: Front wheel drive units 16, 216 316, 416, 516, 616: Driving force transmission unit 18, 218, 318, 418, 518, 618: Rear wheel drive unit 20, 220, 320, 420, 520, 620: Front wheel differential device 22, 222, 322 622: rear wheel differential devices 24, 224, 324, 424, 524, 624: first disconnecting devices 26, 226, 326, 327, 426, 427, 526, 527, 626: second disconnecting devices 28, 228, 328, 428, 429, 528, 529, 628: rotation-sensitive couplings 30, 330, 630: ECU
32, 332, 432, 532, 632: engine 34, 334, 634: transmission 36, 336: drive gear 38: ring gear 40, 80, 380, 640, 680: differential case 42, 44, 82, 84, 282, 284, 382, 384, 642, 644, 682, 684: pinion 46, 48, 86, 88, 286, 288, 386, 388, 646, 648, 686, 688: side gear 50, 650: left front wheel drive shaft 52, 652: Right front wheel drive shaft 54, 354, 654: Left front wheel 56, 356, 656: Right front wheel 58, 358: Differential case shaft 60, 360: Hypoid ring gear shaft 62, 96, 262, 296, 662, 696: Engagement clutch Mechanism 64, 98, 264, 298, 364, 398, 399, 664, 698: Actu Data 66, 78, 278, 378, 478, 578, 638, 678: hypoid ring gear 68: output pinion 70, 74, 670, 674: universal joint 72, 672: propeller shaft 76, 276, 676, 709: drive Pinion 90, 390, 490, 690: Left rear wheel drive shaft 92, 392, 492, 692: Right rear wheel drive shaft 94, 294, 660, 694: Synchronization mechanism 100, 300, 400, 500, 600, 700: Left Rear wheel 102, 302, 402, 502, 602, 702: Right rear wheel 104, 126, 306: Housing 106, 128: Pinion shaft 108, 110, 112, 114, 132, 134: Tapered roller bearing 116: Coupling sleeve 118, 144: Shift fork 120, 146: Shift rod 1 2, 124: cylinders 130, 404, 406: side gear shaft 136: clutch shaft 138: baux ring 140: insert key 142: clutch sleeve 148: pinion 150: roller bearing 152: ball bearing 154: spring 156, 158: shaft hole 658 : Sprocket shaft 668: Output shaft 704, 708: Sprocket 706: Chain belt

Claims (5)

Driving power transmission for a four-wheel drive vehicle capable of switching between a four-wheel drive mode in which driving force is distributed to the first driving wheel and the second driving wheel and a two-wheel driving mode in which driving force is transmitted only to the first driving wheel. In the device,
A first drive unit that transmits driving force from an engine to the first drive wheel;
A driving force transmission unit that transmits the driving force from the first driving unit to the second driving wheel;
A second drive unit for transmitting a drive force from the drive force transmission unit to the second drive wheel;
A rotational difference sensitive coupling that distributes a driving force according to a rotational speed difference between the first drive wheel and the second drive wheel;
A first disconnecting device that disconnects and connects transmission of driving force from the first driving unit to the driving force transmission unit;
A second disconnecting device that disconnects and connects transmission of driving force from the second driving unit to the second driving wheel;
A driving force transmission device for a four-wheel drive vehicle.
2. The driving force transmission device for a four-wheel drive vehicle according to claim 1, wherein the rotation difference sensitive coupling is disposed between the first disconnecting device and the second driving portion. A driving force transmission device for a four-wheel drive vehicle.
2. The driving force transmission device for a four-wheel drive vehicle according to claim 1, wherein the rotation-sensitive coupling is arranged coaxially with an output shaft of the second drive unit. Drive force transmission device.
4. The driving force transmission device for a four-wheel drive vehicle according to claim 1, wherein at least one of the first disconnecting device and the second disconnecting device is connected to a driving force transmitting portion side and an opposite side when connected. A driving force transmission device for a four-wheel drive vehicle, comprising a synchronization mechanism that synchronizes rotation with the vehicle.
  5. The drive force transmission device for a four-wheel drive vehicle according to claim 1, wherein the second disconnecting device is a drive force from the second drive unit to at least one of the left and right sides of the second drive wheel. The transmission force transmission device for four-wheel drive vehicles characterized by cutting and connecting the transmission of the vehicle.

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