JP2012162229A - Driving force transmission device and four-wheel drive vehicle - Google Patents

Abstract

Provided is a driving force transmission device in which abnormal noise is hardly generated at a spline coupling portion even when a propeller shaft is disconnected from both a driving force source and a sub driving wheel.
For example, a front wheel 1 is a main driving wheel, a rear wheel 2 is a sub driving wheel, a driving force is always transmitted to the main driving wheel, and a driving force can be selectively transmitted to the sub driving wheel. In addition, when the driving force is not transmitted to the rear wheel 2, the engine (driving force source) 3 and the propeller shaft 7 are shut off by the first interrupting mechanism 11 and the propeller shaft 7 and the rear wheel (sub driving wheel) are interrupted by the second interrupting mechanism 12. 2), and the gap between the teeth of the spline coupling portion 16 is reduced by displacing the propeller shaft 7 in the direction intersecting the axial direction by the gap reduction actuator 24, so that the propeller shaft 7 is moved to the rear of the engine 3. Even if the wheel 2 is cut off, it is difficult for abnormal noise to occur in the spline coupling portion 16.
[Selection] Figure 1

Description

  The present invention relates to a driving force transmission device for a vehicle, and in particular, one of front and rear wheels of a vehicle is a main driving wheel, the other is a sub driving wheel, the driving force is always transmitted to the main driving wheel, and the auxiliary driving wheel is transmitted. Is suitable for a driving force transmission device capable of selectively transmitting a driving force.

In a four-wheel drive vehicle equipped with such a drive force transmission device, when four-wheel drive is selected, the drive force is transmitted to both the main drive wheel set as one of the front and rear wheels and the sub drive wheel set as the other. While driving performance and stability are improved, driving power is transmitted only to the main driving wheel when two-wheel driving is selected, and fuel consumption (fuel consumption rate) can be improved by blocking driving force transmission to the auxiliary driving wheel. it can.
However, sufficient fuel consumption improvement cannot be achieved simply by interrupting transmission of driving force to the auxiliary driving wheels. Therefore, in Patent Document 1 below, even when transmission of driving force to the auxiliary driving wheel is interrupted, the mass body that is unnecessarily rotated (co-rotated) together with the main driving wheel and auxiliary driving wheel is interrupted (separated). To improve fuel efficiency. Examples of the mass body that is unnecessarily rotated include a propeller shaft for transmitting a driving force to the auxiliary driving wheel, and a front and rear gear mechanism for transmitting the driving force to the propeller shaft.

JP 2004-9954 A

  Incidentally, some propeller shafts for transmitting driving force to the auxiliary drive wheels include, for example, spline coupling portions for absorbing fluctuations in the longitudinal length of the vehicle. When the propeller shaft having such a spline coupling portion is cut off from both the engine that is the driving force source and the auxiliary driving wheel, the teeth of the spline coupling portion vibrate in the gap (backlash) of the spline coupling portion while the vehicle is running. Abnormal noise may occur. In order to solve such a problem, for example, it is conceivable to reduce the backlash of the spline coupling part or to drag and rotate the propeller shaft (co-rotation) with the rotation of the auxiliary driving wheel, for example. The former has a manufacturing restriction because it is necessary to increase the accuracy of the spline connecting portion, and the latter has a problem that fuel consumption is reduced.

  The present invention has been made paying attention to the above-mentioned problems, and a driving force transmission device in which abnormal noise is hardly generated at a spline coupling portion even when the propeller shaft is disconnected from both the driving force source and the auxiliary driving wheel. Is intended to provide.

  In order to solve the above-mentioned problem, an embodiment of the invention is such that either one of the front and rear wheels of a vehicle is a main driving wheel, the other is a sub driving wheel, and the driving force is always transmitted to the main driving wheel. In the driving force transmission device capable of selectively transmitting the driving force, a propeller shaft that transmits the driving force to the auxiliary driving wheel and has a spline coupling portion, and a driving force source and the propeller shaft are intermittently connected. An intermittent mechanism, a second intermittent mechanism for intermittently connecting the propeller shaft and the auxiliary drive wheel, and a displacement between the propeller shaft in a direction intersecting the axial direction of the propeller shaft, thereby forming a gap between the teeth of the spline coupling portion. The gap reducing means for decreasing, the driving force source and the propeller shaft are shut off by the first interrupting mechanism when the driving force is not transmitted to the auxiliary driving wheel, and the propeller shaft and the auxiliary driving wheel are disconnected by the second interrupting mechanism. And a control means for reducing the gap between the teeth of the spline coupling part by blocking and displacing the propeller shaft in a direction intersecting the axial direction of the propeller shaft by the gap reducing means. Is.

In addition, a coupling mechanism for coupling and supporting the propeller shaft to the vehicle body is provided, and the gap reducing means displaces the propeller shaft in a direction intersecting the axial direction of the propeller shaft by displacing the coupling mechanism. It is characterized by.
The connection mechanism includes an intermediate support for connecting an axially intermediate portion of the propeller shaft to a vehicle body, and the gap reducing means displaces the intermediate support in a direction intersecting the axial direction of the propeller shaft. It is characterized by being.

  The intermediate support includes an intermediate support bearing for rotatably supporting the propeller shaft, an elastic member disposed on an outer periphery of the intermediate support bearing, and the intermediate support bearing on the vehicle body via the elastic member. A bracket for coupling, and a coupling member for coupling the bracket to a vehicle body, wherein the gap reducing means rotates the bracket of the intermediate support around the axis of the coupling member to cause the intermediate support to move to the propeller. Displacement is made in a direction crossing the axial direction of the shaft.

  The control means shuts off the driving force source and the propeller shaft by the first interrupting mechanism and interrupts the propeller shaft and the auxiliary driving wheel by the second interrupting mechanism when the driving force is not transmitted to the auxiliary driving wheel. Then, the gap between the teeth of the spline coupling portion is reduced by displacing the propeller shaft in a direction intersecting the axial direction of the propeller shaft by the gap reducing means.

  Further, the control means releases the displacement of the propeller shaft in the direction intersecting the axial direction of the propeller shaft by the gap reducing means when the driving force is transmitted to the auxiliary driving wheel, and the teeth of the spline coupling portion are released. After the gap between them is restored, the driving force source and the propeller shaft are connected by the first interrupting mechanism, and the propeller shaft and the auxiliary driving wheel are connected by the second interrupting mechanism. is there.

  Thus, according to an embodiment of the invention, either one of the front and rear wheels of the vehicle is a main drive wheel, the other is a sub drive wheel, a driving force is constantly transmitted to the main drive wheel, In the driving force transmission device capable of selectively transmitting the driving force, the driving force source and the propeller shaft are shut off by the first interrupting mechanism when the driving force is not transmitted to the auxiliary driving wheel, and the propeller shaft is disconnected by the second interrupting mechanism. The propeller shaft is cut off from the auxiliary drive wheel, and the propeller shaft is displaced in the direction intersecting the axial direction of the propeller shaft by the gap reduction means to reduce the gap between the teeth of the spline coupling portion. Even if it is cut off from both the power source and the auxiliary drive wheel, abnormal noise hardly occurs at the spline coupling portion.

Further, since the gap reducing means is configured to displace the propeller shaft in a direction intersecting the axial direction of the propeller shaft by displacing the coupling mechanism for connecting the propeller shaft to the vehicle body, the coupling mechanism is an existing one. In this case, an increase in the number of parts can be suppressed and prevented.
In addition, the clearance reduction means has a structure in which the intermediate support for connecting the propeller shaft to the vehicle body is displaced in a direction crossing the axial direction of the propeller shaft, so that the increase in the number of parts is suppressed by using the existing intermediate support Can be prevented.

  In addition, the intermediate support is configured to rotatably support the propeller shaft, an elastic support member disposed on the outer periphery of the intermediate support bearing, and an intermediate support bearing connected to the vehicle body via the elastic member. A bracket and a connecting member for connecting the bracket to the vehicle body, and the clearance reducing means rotates the bracket of the intermediate support around the axis of the connecting member to cross the intermediate support with the axis direction of the propeller shaft. Since it is set as the structure displaced to (2), it can be made a simple structure using the existing member.

  Further, the control means, when the driving force is not transmitted to the auxiliary driving wheel, after the driving force source and the propeller shaft are shut off by the first interrupting mechanism and the propeller shaft and the auxiliary driving wheel are shut off by the second interrupting mechanism, Since the propeller shaft is displaced in the direction intersecting the axial direction of the propeller shaft by the gap reduction means to reduce the gap between the teeth of the spline coupling portion, it is possible to smoothly shift from four-wheel drive to two-wheel drive. it can.

  Further, the control means cancels the displacement of the propeller shaft in the direction intersecting the axial direction of the propeller shaft by the gap reduction means when the driving force is transmitted to the auxiliary drive wheel, and the gap between the teeth of the spline coupling portion is eliminated. After returning to the original state, the driving force source and the propeller shaft are connected by the first interrupting mechanism and the propeller shaft and the auxiliary driving wheel are connected by the second interrupting mechanism. Can be migrated.

1 is a schematic configuration diagram illustrating an embodiment of a four-wheel drive vehicle to which a driving force transmission device of the present invention is applied. It is explanatory drawing of the center support mounted in the four-wheel drive vehicle of FIG. It is explanatory drawing of an effect | action of the center support of FIG. It is a flowchart of the arithmetic processing performed with the controller of FIG.

Next, an embodiment of the driving force transmission device of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of a four-wheel drive vehicle to which the driving force transmission device of this embodiment is applied. In the figure, reference numeral 1 indicates the left and right front wheels of the vehicle, and reference numeral 2 indicates the left and right rear wheels of the vehicle. In the four-wheel drive vehicle of this embodiment, the driving force is always transmitted to the front wheel 1 and the driving force is selectively transmitted to the rear wheel 2. A wheel that constantly transmits driving force is defined as a main driving wheel, and a wheel that selectively transmits driving force is defined as a sub driving wheel.

  In the four-wheel drive vehicle of this embodiment, the engine 3 that is a driving force source is provided in front of the vehicle. The driving force of the engine 3 is shifted by the transmission 4 and transmitted to the transfer 5 and the front wheel differential mechanism 6. The driving force transmitted to the front wheel differential mechanism 6 is transmitted from the front wheel drive shaft 10 to the front wheel 1 which is the main driving wheel. The transfer 5 is used to distribute the driving force to the rear wheel 2 which is the auxiliary driving wheel. The driving force distributed by the transfer 5 is a propeller shaft 7, a rear wheel differential mechanism 8, and a rear wheel drive shaft 9. Is transmitted to the rear wheel 2 which is the auxiliary driving wheel.

  Between the said transfer 5 and the propeller shaft 7, the 1st interruption mechanism 11 which can connect and interrupt | block both is interposed. Further, a second intermittent mechanism 12 capable of connecting or blocking between the rear wheel differential mechanism 8 and the propeller shaft 7 is interposed. For the first interrupting mechanism 11 and the second interrupting mechanism 12, for example, a known electromagnetic powder clutch can be used. The first intermittent mechanism 11 intermittently connects the transfer 5 and the propeller shaft 7 by the first intermittent actuator 13, and the second intermittent mechanism 12 intermittently connects the rear wheel differential mechanism 8 and the propeller shaft 7 by the second intermittent actuator 14. In this embodiment, when the first intermittent actuator 13 and the second intermittent actuator 14 are turned on, the first intermittent mechanism 11 and the second intermittent mechanism 12 cause the transfer 5 and the propeller shaft 7, and the propeller shaft 7 and the rear wheel differential mechanism 8. Are connected to each other. The first intermittent mechanism 11 is intended to intermittently connect the engine 3 and the propeller shaft 7 which are driving force sources, and the second intermittent mechanism 12 is the rear wheel 2 and the propeller shaft which are auxiliary drive wheels. 7 is intended to be interrupted, the portion where these are provided is not limited to the above as long as the purpose is met.

  In the four-wheel drive vehicle according to the present embodiment, the propeller shaft 7 is divided into two parts (strictly, three parts) in the front-rear direction at the central part (intermediate part) in the axial direction. And a cross joint connecting portion 17. Further, the vicinity of the divided portion is connected and supported to the vehicle body by a center support (intermediate support) 15 which is a connecting mechanism. FIG. 2 shows details in the vicinity of the center support 15. The split portion of the propeller shaft 7 has a connecting shaft 7c interposed between a front shaft 7a in front of the vehicle and a rear shaft 7b in the rear of the vehicle, and the connecting shaft 7c and the front shaft 7a are connected by a spline connecting portion 16. The connecting shaft 7c and the rear shaft 7b are connected by a cross joint connecting portion 17. For example, the spline coupling portion 16 is for absorbing fluctuations in the length of the propeller shaft 7 in the axial direction, and the cross joint coupling portion 17 is for absorbing displacement in a direction crossing the axial direction of the propeller shaft 7, for example. belongs to.

  In this embodiment, the front shaft 7a and the rear shaft 7b of the propeller shaft 7 have substantially the same diameter, and the connecting shaft 7c has a smaller diameter. Then, the spline shaft portion 16a is formed at the vehicle front end portion of the connecting shaft 7c, and the spline hole portion 16b is formed at the vehicle rear end portion of the front shaft 7a. . Further, a yoke (bifurcated portion) 17a is formed at the vehicle rear end portion of the connecting shaft 7c, and a yoke 17a is also formed at the vehicle front end portion of the rear shaft 7b so that the cross spider 17b can be freely rotated between the yokes 17a. The cross joint connecting portion 17 is generally called a cardan joint.

  The center support 15 connects and supports the connecting shaft 7c to the vehicle body in a rotatable manner. As a result, the vicinity of the spline coupling portion 16 and the cross joint coupling portion 17 is connected and supported by the vehicle body. The center support 15 includes a center support bearing (intermediate support bearing) 18 that rotatably supports the connecting shaft 7, a circular elastic member 19 provided on the outer periphery of the center support bearing 18, and a center via the elastic member 19. A U-shaped bracket 20 for connecting the support bearing 18 to the vehicle body and a connecting member 21 for connecting the bracket 20 to the vehicle body are provided.

  The elastic member 19 includes an outer ring 19a supported by the bracket 20, an inner ring 19b fitted to the center support bearing 18, and an elastic body 19c provided between the outer ring 19a and the inner ring 19b. The elastic body 19c is made of, for example, a rubber member having a rose (bellows portion) in which a plurality of wrinkles are concentrically formed, and the center support bearing 18 is elastically supported by the elastic body 19c. Further, flanges 22 are provided at the upper end of the opening of the U-shaped bracket 20 so as to extend toward both outer sides in the vehicle width direction, and mounting holes for connecting the bracket 20 to the vehicle body are provided in each of the flanges 22. 23 is formed. Of these mounting holes 23, the left mounting hole 23 in the figure is a through hole having a circular cross section, but the right mounting hole 23 in the figure has an arc shape centered on the left mounting hole 23 in the figure. It is a through hole.

  The connecting member 21 is composed of, for example, a hexagonal bolt, and a sliding bush 26 is fitted into the threaded portion of the hexagonal bolt and inserted into the mounting hole 23, and the threaded portion of the hexagonal bolt is tightened into the threaded hole of the vehicle body (not shown) by screwing. Accordingly, when the right flange 22 shown in FIG. 2 is moved in the vehicle front-rear direction, the bracket 20 rotates around the axis of the left connecting member 21, thereby causing the propeller shaft 7 to cross the axis direction. Can be displaced.

  A rod of a clearance reducing actuator 24 composed of, for example, an electromagnetic solenoid is connected to the vehicle rear portion of the right flange 22 shown in FIG. This gap reduction actuator 24 constitutes a gap reduction means. The vehicle rear end of the clearance reduction actuator 24 is attached to the vehicle body by an attachment member 25 such as a hexagon socket head bolt. In the gap reducing actuator 24 of the present embodiment, the rod contracts when not operating, and the rod extends when operating. In a state where the rod of the clearance reducing actuator 24 is contracted, the front shaft 7a, the connecting shaft 7c, and the rear shaft 7b constituting the propeller shaft 7 are located on the same axis as shown in FIG. 3a. In this state, as is well known, there is a gap (backlash) between the teeth of the spline shaft portion of the spline coupling portion 16 and the teeth of the spline hole portion.

  On the other hand, when the rod of the clearance reducing actuator 24 is extended, as shown in FIG. 3B, the bracket 20 of the center support 15 is rotated around the axis of the connecting member 21 in the upper part of the drawing (corresponding to the left in the drawing in FIG. 2). Since the support bearing 18 is also rotated in the same direction, the axis of the connecting rod 7c is displaced so as to be bent with respect to the axis of the rear shaft 7b. That is, when the rod of the clearance reducing actuator 24 is extended, the connecting shaft 7c, which is a part of the propeller shaft 7, is displaced in a direction intersecting the axial direction of the front shaft 7a. When the connecting shaft 7c is displaced in the direction crossing the axial direction in this way, the teeth of the spline hole portion of the spline coupling portion 16 formed on the front shaft 7a and the teeth of the spline shaft portion formed on the connecting shaft 7c. The gap between the teeth becomes smaller, more specifically, the teeth come into contact with each other. And if the clearance gap between the teeth of the spline coupling | bond part 16 becomes small, the jump of the tooth in what is called a backlash will be suppressed and it will become difficult to generate | occur | produce abnormal noise.

  At this time, since the elastic member 19 is interposed between the bracket 20 of the center support 15 that is actually driven by the clearance reduction actuator 24 and the center support bearing 18 that supports the connecting shaft 7c, the bracket by the clearance reduction actuator 24 is provided. Even if the displacement of 20 is not finely adjusted, the gap between the teeth of the spline coupling portion 16 is appropriately reduced by the displacement of the connecting shaft 7c, and the generation of abnormal noise can be efficiently prevented. That is, even if the rod of the clearance reducing actuator 24 is stroked to a large extent, an excessive stroke more than the stroke for reducing the clearance between the teeth of the spline coupling portion 16 is not enough for the bellows-like elastic body 19c of the elastic member 19. Absorbed by deformation. Therefore, it is possible to avoid excessive contact between the teeth of the spline coupling portion 16 or an excessive load applied to the clearance reducing actuator 24. Incidentally, FIG. 3B is emphasized for easy understanding of the displacement state of the connection shaft 7c, and the displacement of the actual connection shaft 7c, that is, the spline coupling portion 16, is very small.

  Returning to FIG. 1, the first intermittent actuator 13, the second intermittent actuator 14, and the clearance reduction actuator 24 transmit the driving force to the wheels 1 and 2, particularly the driving force to the rear wheel 2 that is the auxiliary driving wheel. It is controlled by a controller (control means) 27 for controlling. The controller 27 controls the first intermittent actuator 13, the second intermittent actuator 14, and the clearance reducing actuator 24 according to an input signal of the driving force distribution changeover switch 28 operated by the driver, for example. The driving force transmission control to the rear wheel 2 that is the auxiliary driving wheel can be combined with, for example, driving force distribution control according to the traveling state of the vehicle and the operation state by the driver. In that case, the four-wheel drive command of the driving force distribution control result may be added to the four-wheel drive command of the arithmetic processing described later.

  FIG. 4 shows a flow of arithmetic processing performed by the controller (control means) 27. The controller 27 is configured by an arithmetic device such as a microcomputer or an arithmetic circuit, for example. This calculation process is executed as a timer interrupt process, for example, every predetermined sampling cycle. First, in step S1, it is determined whether or not the input signal of the driving force distribution changeover switch 28 is in the four-wheel drive command state. If it is in the drive command state, the process proceeds to step S2, and if not, the process proceeds to step S3.

In step S3, the first intermittent actuator 13 and the second intermittent actuator 14 are turned off to shut off the first intermittent mechanism 11 and the second intermittent mechanism 12 to drive the rear wheel 2 that is the auxiliary drive wheel. After the transmission is canceled, the process proceeds to step S5.
In step S5, the clearance of the spline coupling portion 16 of the propeller shaft 7 is reduced by the clearance reduction actuator 24, and then the process returns to the main program.

On the other hand, in step S2, the clearance reduction of the spline coupling portion 16 of the propeller shaft 7 by the clearance reduction actuator 24 is canceled, and then the process proceeds to step S4.
In step S4, the first intermittent actuator 13 and the second intermittent actuator 14 are turned on to connect the first intermittent mechanism 11 and the second intermittent mechanism 12 so that the driving force is applied to the rear wheel 2 that is the auxiliary driving wheel. After transmission, return to the main program.

  According to this calculation process, the engine 3 that is a driving force source is driven by the first intermittent mechanism 11 during the transition from the four-wheel driving state to the two-wheel driving state, that is, when the driving force is released to the rear wheel 2 that is the auxiliary driving wheel. And the propeller shaft 7 are shut off, and the propeller shaft 7 and the rear wheel 2 as the auxiliary drive wheel are shut off by the second intermittent mechanism 12, and then the propeller shaft 7 is displaced in the direction intersecting the axial direction by the clearance reduction actuator 24. Since the gap between the teeth of the spline coupling portion 16 is reduced, the backlash of the spline coupling portion 16 is not inadvertently lost, and a smooth transition from the four-wheel drive state to the two-wheel drive state is achieved. Can do.

  Further, during the transition from the two-wheel drive state to the four-wheel drive state, that is, when the driving force is transmitted to the rear wheel 2 that is the auxiliary drive wheel, the clearance reduction actuator 24 moves in the direction intersecting the axial direction of the propeller shaft 7. Is released and the gap between the teeth of the spline coupling portion 16 is restored, and then the engine 3 that is the driving force source and the propeller shaft 7 are connected by the first interrupting mechanism 11 and the propeller is connected by the second interrupting mechanism 12. Since the shaft 7 and the rear wheel 2 that is the auxiliary drive wheel are connected, the propeller shaft 7 is not rotated without the backlash of the spline coupling portion 16, and the two-wheel drive state is changed to the four-wheel drive state. Smooth transition.

  In particular, in the transition period from the four-wheel drive state to the two-wheel drive state, when the rotational inertia after the separation of the propeller shaft 7 is inconvenient for reducing the gap between the teeth of the spline coupling portion 16, for example, A waiting time for loss of rotational inertia may be provided between step S3 and step S5 of the arithmetic processing.

  As described above, in the driving force transmission device according to the present embodiment, for example, the front wheel 1 is a main driving wheel, the rear wheel 2 is a sub driving wheel, the driving force is always transmitted to the main driving wheel, and the sub driving wheel is selective. When the driving force can be transmitted to the rear wheel 2, the engine (driving force source) 3 and the propeller shaft 7 are shut off by the first interrupting mechanism 11 and the propeller is driven by the second interrupting mechanism 12 when the driving force is not transmitted to the rear wheel 2. The shaft 7 and the rear wheel (sub drive wheel) 2 are shut off, and the gap between the teeth of the spline coupling portion 16 is reduced by displacing the propeller shaft 7 in the direction intersecting the axial direction by the gap reduction actuator 24. Therefore, even if the propeller shaft 7 is cut off from both the engine 3 and the rear wheel 2, abnormal noise is hardly generated in the spline coupling portion 16.

Further, the gap reduction actuator 24 displaces the propeller shaft 7 in a direction intersecting the axial direction by displacing the center support 15 which is a coupling mechanism for coupling the propeller shaft 7 to the vehicle body. When 15 is an existing one, an increase in the number of parts can be suppressed and prevented.
Further, since the gap reduction actuator 24 is configured to displace the center support 15 for connecting the propeller shaft 7 to the vehicle body in a direction intersecting the axial direction of the propeller shaft 7, the number of parts can be increased by using the existing center support 15. Can be suppressed and prevented.

  In addition, the center support 15 rotatably supports the propeller shaft 7, a center support bearing 18, an elastic member 19 disposed on the outer periphery of the center support bearing 18, and the center support bearing 18 via the elastic member 19. And a connecting member 21 for connecting the bracket 20 to the vehicle body, and the clearance reduction actuator 24 rotates the bracket 20 of the center support 15 around the axis of the connecting member 21. Since the center support 15 is displaced in the direction intersecting with the axial direction of the propeller shaft 7, the existing member can be used and the configuration can be simplified.

  In the embodiment, the propeller shaft 7 is displaced in a direction intersecting the axial direction by displacing the axis of the connecting rod 7c so as to be bent with respect to the axis of the rear shaft 7b by the clearance reducing actuator 24. However, for example, the propeller shaft 7 can be displaced in the direction intersecting the axial direction even if the connecting rod 7c is displaced laterally while keeping the axis of the connecting rod 7c parallel to the axis of the rear shaft 7b. Even if it does so, the clearance gap between the teeth of the spline coupling | bond part 16 can be made small.

  The division of the propeller shaft is not limited to two divisions, and may be divided into three or more divisions. Further, the spline coupling portion may be disposed in all the divided portions or may not be disposed. For example, when the spline coupling portion is disposed in the adjacent divided portion, if any spline coupling portion is displaced in a direction crossing the axial direction, the gap between all teeth of the adjacent spline coupling portion Can be reduced.

In the above embodiment, the gap reduction actuator 24 constituted by an electromagnetic solenoid or the like is used as the gap reduction means. However, the gap reduction means is not limited to this, and various actuators such as a motor and a cylinder are used. Can do.
The driving force source is not limited to the engine, and for example, a well-known hybrid driving force source in which a motor and an engine are combined, or a motor driven by, for example, a fuel cell or a storage battery can be applied.

Further, the present invention can be applied to a vehicle in which the rear wheels are set as main driving wheels and the front wheels are set as auxiliary driving wheels. In that case, the engine may be mounted on the rear side of the vehicle.
In addition to a vehicle having four wheels, the present invention can be applied to, for example, a three-wheel buggy having one front wheel and two rear wheels.

1 is the front wheel (main drive wheel)
2 is the rear wheel (sub drive wheel)
3 is the engine (drive power source)
4 is a transmission, 5 is a transfer, 6 is a front wheel differential mechanism, 7 is a propeller shaft, 8 is a rear wheel differential mechanism, 9 is a rear wheel drive shaft, 10 is a front wheel drive shaft, 11 is a first intermittent mechanism, and 12 is a second intermittent mechanism. 1 intermittent actuator 14 is second intermittent actuator 15 is center support (connecting mechanism, intermediate support)
16 is a spline joint 17 is a cross joint joint 18 is a center support bearing (intermediate support bearing)
Reference numeral 19 denotes an elastic member, 20 denotes a bracket, 21 denotes a connecting member, 22 denotes a flange, 23 denotes a mounting hole, and 24 denotes a clearance reduction actuator (gap reduction means).
25 is a mounting member 26 is a sliding bush 27 is a controller (control means)
28 is a driving force distribution changeover switch

Claims (7)

  One of the front and rear wheels of the vehicle is the main driving wheel, the other is the sub driving wheel, and the driving force is always transmitted to the main driving wheel and can be selectively transmitted to the sub driving wheel. In the transmission device, a propeller shaft that transmits a driving force to the auxiliary driving wheel and has a spline coupling portion, a first interruption mechanism that intermittently connects the driving force source and the propeller shaft, and the propeller shaft and the auxiliary driving wheel are intermittently connected. A second intermittent mechanism, a gap reducing means for displacing the propeller shaft in a direction intersecting the axial direction of the propeller shaft to reduce a gap between teeth of the spline coupling portion, and driving to the auxiliary drive wheel When the force is not transmitted, the driving force source and the propeller shaft are shut off by the first interrupting mechanism, the propeller shaft and the auxiliary driving wheel are shut off by the second interrupting mechanism, and the propeller is driven by the clearance reducing means. Driving force transmission apparatus is characterized in that a control means for reducing the gap between the teeth ends of the spline coupling portion is displaced in the direction perpendicular to the axial direction of the propeller shaft to Yafuto.   A coupling mechanism for coupling and supporting the propeller shaft to a vehicle body is provided, and the gap reducing means displaces the propeller shaft in a direction crossing the axial direction of the propeller shaft by displacing the coupling mechanism. The driving force transmission device according to claim 1.   The connection mechanism includes an intermediate support for connecting the axial direction intermediate portion of the propeller shaft to a vehicle body, and the gap reducing means displaces the intermediate support in a direction intersecting the axial direction of the propeller shaft. The driving force transmission device according to claim 2, wherein the driving force transmission device is provided.   The intermediate support couples the intermediate support bearing to the vehicle body via the intermediate support bearing for rotatably supporting the propeller shaft, an elastic member disposed on the outer periphery of the intermediate support bearing, and the elastic member. A bracket for connecting the bracket to the vehicle body, and the gap reducing means rotates the bracket of the intermediate support around the axis of the connection member, thereby rotating the intermediate support to the propeller shaft. The driving force transmission device according to claim 3, wherein the driving force transmission device is displaced in a direction crossing an axial direction.   The control means shuts off the driving force source and the propeller shaft by the first interrupting mechanism and interrupts the propeller shaft and the auxiliary driving wheel by the second interrupting mechanism when the driving force is not transmitted to the auxiliary driving wheel. 5. The gap between the teeth of the spline coupling portion is reduced by displacing the propeller shaft in a direction intersecting the axial direction of the propeller shaft by the gap reducing means. The driving force transmission device according to one item.   The control means releases the displacement of the propeller shaft in the direction intersecting the axial direction of the propeller shaft by the gap reduction means when the driving force is transmitted to the auxiliary drive wheel, and between the teeth of the spline coupling portion. The driving force source and the propeller shaft are connected by the first interrupting mechanism and the propeller shaft and the auxiliary driving wheel are connected by the second interrupting mechanism after the gap is restored. The driving force transmission device according to claim 5.   A four-wheel drive vehicle comprising the driving force transmission device according to any one of claims 1 to 6.

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