JP2007078177A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device having compact construction with a less number of components for transmitting the rotation input to a rotating shaft to a wheel at a great reduction ratio. <P>SOLUTION: The rotating shaft 11 is provided coaxially with an inward member 3 consisting of a hub wheel 4 and a bearing inner ring 5, and external gears 16a, 16b are rotatably provided outside eccentric portions 14a, 14b formed on the rotating shaft 11. Each of the external gears 16a, 16b is meshed with internal teeth 18 formed on the inner periphery of a casing 1, and the external gears 16a, 16b are revolved by the rotation of the rotating shaft while being meshed one by one with internal teeth 18 and the external gears 16a, 16b are rotated by a difference in number between external teeth 17 and the internal teeth 18 per one rotation of the rotating shaft 11. The rotating motion thereof is transmitted via a torque transmitting means 20 to the inward member 3 to give speed reducing rotation to the inward member 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission device that decelerates rotation input to a rotating shaft and transmits the reduced speed to a vehicle wheel.

  As power transmission devices that transmit power to the wheels of a vehicle, those described in Patent Document 1 and Patent Document 2 are conventionally known. An in-wheel motor drive device described in Patent Document 1 includes an electric motor that generates a driving force, a wheel shaft to which a wheel of a wheel is connected, and a speed reducer that decelerates the rotation of the electric motor and transmits it to the wheel shaft. As the speed reducer, a parallel shaft type gear speed reducer in which a plurality of gears having different numbers of teeth is combined is employed.

  On the other hand, in the electric vehicle speed reduction device described in Patent Document 2, a planetary gear speed reduction mechanism is provided in two stages between the rotor of the electric motor and the wheel hub. Is distributed to the left and right unsprung wheels via the drive shaft.

JP 2005-7914 A JP-A-5-332401

  By the way, in the in-wheel motor drive device described in Patent Document 1, since a large-scale power transmission mechanism such as a propeller shaft and a differential is not necessary, attention has been paid from the viewpoint of reducing the weight and downsizing of the vehicle. The parallel shaft type gear reducer has a reduction ratio of about 1/2 to 1/3, and is not sufficient as a reducer mounted on an in-wheel motor drive device, and the weight of the reducer is heavy. However, the increase in unsprung weight has the disadvantage that the ride comfort becomes worse, and it has not yet been put into practical use.

  On the other hand, although the planetary gear type reduction mechanism of the reduction gear for electric vehicles described in Patent Document 2 can obtain a large reduction ratio as compared with the parallel shaft type gear reduction device, the reduction gear mounted on the in-wheel motor drive device. The machine is still inadequate. In order to obtain a sufficient reduction ratio, it is necessary to make a planetary gear type reduction mechanism composed of a sun gear, ring gear, pinion gear and pinion gear carrier in a multi-stage configuration, which increases the number of parts and makes it difficult to make it compact. The problem of increasing the weight and size of the reducer occurs.

  An object of the present invention is to provide a power transmission device having a compact configuration with a small number of parts, which can transmit rotation input to a rotary shaft to a wheel with a large reduction ratio.

  In order to solve the above problems, in the present invention, an outer member attached to a vehicle body and having a double-row raceway surface formed on an inner periphery of an end on the outboard side, and a double-row raceway of the outer member An inner member having a double-row raceway surface facing the surface in the radial direction on the outer periphery and having a wheel mounting flange formed on an outer periphery of an end located outside the outer member; and a plurality of the outer members A double-row rolling element incorporated between the raceway surface of the row and the double-row raceway surface of the inner member, and an eccentric portion arranged coaxially with the inner member and positioned inside the outer member A rotating shaft formed with the outer gear, and an outer gear that is rotatably supported by an eccentric portion of the rotating shaft and meshes with an inner tooth provided on the inner periphery of the outer member, and has fewer teeth than the inner tooth. , Provided between the outer gear and the inner member to freely revolve the outer gear in accordance with the eccentric rotation of the eccentric portion. And, and, it was adopted a structure composed of a torque transmitting means for transmitting the rotation motion to the inner member.

  In the power transmission device having the above-described configuration, when the rotation shaft is rotated, the eccentric portion rotates eccentrically, and the external gear rotatably supported by the eccentric portion and the inner teeth formed on the inner periphery of the outer member are 1 Revolve around the rotation axis while meshing one by one.

  At this time, since the number of external teeth of the external gear is smaller than the number of internal teeth formed on the inner periphery of the outer member, the external gear rotates by the difference in the number of teeth between the internal teeth and the external teeth per one rotation of the rotating shaft. Rotating in the direction opposite to the rotation direction of the shaft, the rotation motion is transmitted to the inner member through the torque transmission means, and the rotation of the rotating shaft is transmitted to the wheel connected to the inner member at a reduced speed. become.

  Here, the external teeth formed on the outer periphery of the external gear and the internal teeth formed on the inner periphery of the outer member may be involute teeth, or the external teeth formed on the outer periphery of the external gear are trochoidal curve teeth. The inner teeth that mesh with the outer teeth may be used as outer pins. Like the latter, the external teeth formed on the outer periphery of the external gear have a trochoidal curved tooth profile, and the internal teeth are external pins, so that the meshing rate can be increased and the teeth are less likely to break. Power transmission device can be obtained.

  In the power transmission device according to the present invention, as an inward member, a hub wheel having a flange for mounting a wheel on the outer periphery, and a hub wheel inserted into the hub wheel and coupled to the hub wheel by expanding and caulking from an inner diameter portion. What consists of a bearing inner ring | wheel which has the cylinder part to be performed in the edge part by the side of an outboard is employable.

  Further, as torque transmission means, a plurality of inner pins are provided on one of the opposing surfaces facing the external gear and the inner member in the axial direction at equal intervals on a concentric circle, and each inner pin is a pin formed on the other of the opposing surfaces It is possible to employ a configuration in which each inner pin is brought into contact with a part of the inner periphery of each circular hole by being inserted into a circular hole having a diameter larger than the diameter.

  Here, when the inner pin is rotatably supported or a roller is rotatably fitted to the inner pin and each roller is brought into contact with a part of the inner periphery of the circular hole, the contact between the inner pin and the circular hole rolls. Since contact occurs, the contact resistance is small, and torque loss can be reduced.

  In the power transmission device according to the present invention, the counterweight is attached to the rotating shaft so that the center of gravity thereof is displaced in the circumferential direction by 180 ° with respect to the eccentric direction of the eccentric portion. Vibrations due to rotation can be canceled out, and a power transmission device with less vibration can be obtained.

  In addition, there are two eccentric parts that rotatably support the external gear, and by providing the two eccentric parts with a 180 ° phase shift in the circumferential direction, the power of the rotating shaft is transmitted from two paths to the inner member. Since the load of the rotational power transmitted from one path can be reduced, more stable rotational power can be transmitted, and vibrations generated by the eccentric rotation of the eccentric portion can be canceled each other. Thus, a power transmission device that generates less vibration can be obtained.

  Furthermore, a small and compact in-wheel motor drive device can be formed by connecting a rotor of an electric motor for rotational drive to the rotary shaft.

  As described above, in the present invention, when the rotation shaft is rotated, the external gear supported by the eccentric portion is formed between the internal teeth and the external gear formed on the inner periphery of the outer member per one rotation of the rotation shaft. The wheel rotates by the difference in the number of teeth of the external teeth formed on the outer periphery, and the rotation motion is transmitted to the inner member via the torque transmission means, so that the wheel is attached with a large reduction ratio to the rotation input to the rotating shaft. Can be transmitted to the inner member.

  Further, the speed reduction mechanism has a number of parts consisting of internal teeth formed on the inner periphery of the outer member, an external gear supported by the eccentric portion of the rotating shaft, and torque transmission means for transmitting the rotation of the external gear. Since there are few structures, the power transmission device of a compact structure can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a casing 1 as an outer member attached to a vehicle body includes a casing body 1a and a cover 1b for closing an end opening on the inboard side of the casing body 1a. A double-row track surface 2 is formed on the inner periphery of the end portion on the outboard side.

  An inward member 3 is provided in the end of the casing 1 on the outboard side. The inner member 3 includes a hub ring 4 and a bearing inner ring 5. The bearing inner ring 5 has a cylindrical portion 5 a at one end, and the cylindrical portion 5 a is fitted into the hub ring 4, and extends from the inner diameter portion. It is integrated with the hub wheel 4 by expansion caulking.

  In addition, in order to increase the coupling force by diameter expansion caulking, it is preferable to form fine irregularities 5b on at least one of the inner diameter surface of the hub wheel 4 and the outer diameter surface of the cylindrical portion 5a.

  A wheel mounting flange 6 is formed on the outer periphery of the end portion of the hub wheel 4 located outside the casing 1. Further, on the outer periphery of the end portion of the hub wheel 4 located in the casing 1, a raceway surface 7 is provided that radially faces one of the double-row raceway surfaces 2 formed on the inner periphery of the end portion of the casing 1. .

  On the other hand, the bearing inner ring 5 is provided with a raceway surface 8 that radially opposes the other of the double-row raceway surfaces 2 on the outer periphery of one end portion, and a flange 9 is formed at the other end.

  A double row rolling element 10 is incorporated between the double row raceway surfaces 7 and 8 of the inner member 3 and the double row raceway surface 2 of the casing 1, and the inner member 3 is rotated by the double row rolling element 10. It is supposed to be free.

  A rotating shaft 11 provided coaxially with the inner member 3 passes through the cover 1b of the casing 1 and is rotated by a bearing 12 incorporated in the penetrating portion and a bearing 13 incorporated in the other end portion of the bearing inner ring 5. It is supported freely.

  Two eccentric portions 14 a and 14 b are provided at the end portion of the rotating shaft 11 located in the casing 1. The eccentric portions 14a and 14b are 180 degrees out of phase in the circumferential direction, and the external gears 16a and 16b are rotatably supported by bearings 15 fitted to the outer circumferences of the eccentric portions 14a and 14b.

  As shown in FIG. 3, the external gears 16 a and 16 b have a plurality of external teeth 17 on the outer periphery, and the external teeth 17 mesh with internal teeth 18 provided on the inner periphery of the casing 1. The number of teeth 17 is smaller than the number of internal teeth 18. Here, the outer teeth 17 have a trochoidal curved tooth profile, while the inner teeth 18 are rotatably supported by the outer pins 18a supported at both ends by the casing body 1a and the cover 1b and the outer pins 18a. It consists of a roller 18b.

  In the embodiment, a needle roller bearing is used as the roller 18b from the viewpoint of reducing the radial thickness as shown in FIG. 4, but the present invention is not limited to this. For example, any rolling bearing can be adopted regardless of whether the rolling element is a roller or a ball, such as a cylindrical roller bearing, a tapered roller bearing, an angular ball bearing, a four-point contact ball bearing, and a self-aligning roller bearing. it can.

  The inner teeth 18 may be formed by the outer pins 18a without the roller 18b. Further, the outer teeth 17 and the inner teeth 18 may be involute curved tooth forms.

  As shown in FIGS. 1 and 3, between the outer gears 16a and 16b and the flange 9 formed on the bearing inner ring 5, the revolving motion of the outer gears 16a and 16b is made free so that the rotation motion is an inner member. Torque transmitting means 20 for transmitting to 3 is provided.

  The torque transmission means 20 is provided with a plurality of inner pins 21 on a side surface facing the external gear 16b of the flange 9 formed on the bearing inner ring 5 at equal intervals on the same circle centering on the axis of the bearing inner ring 5. A roller 22 is rotatably fitted to the inner pin 21, and each roller 22 is positioned in a circular hole 23 larger in diameter than the roller diameter formed in the external gears 16a and 16b, and a part of the inner periphery of the circular hole 23 is placed. It is trying to contact.

  In the embodiment, the rotary shaft 11 is provided with two eccentric portions 14a and 14b, and the external gears 16a and 16b are rotatably provided on the eccentric portions 14a and 14b. Therefore, the roller 22 is supported by the flange 9. The inner pin 21 is provided and the outer gears 16a and 16b are provided with the circular holes 23. However, in the power transmission device having one outer gear, the outer gear is provided with the inner pin for supporting the roller and the flange is formed with the circular hole. You may make it do.

  Moreover, although the needle roller bearing is employ | adopted as the roller 22, you may make it use another rolling bearing. Note that the roller 22 may be omitted, the inner pin 21 may be rotatably supported, and the inner pin 21 may be brought into contact with a part of the inner periphery of the circular hole 23.

  As shown in FIG. 2, the rotating shaft 11 is provided with a pair of counterweights 24 at positions outside the two eccentric portions 14a and 14b. The pair of counterweights 24 are attached so that the center of gravity g is positioned in the direction opposite to the eccentric direction of the adjacent eccentric portions 14a and 14b.

  Here, as shown in FIG. 2, if the center point between the two eccentric portions 14a and 14b is G, the eccentric rotation made up of the eccentric portion 14a, the external gear 16a and the counterweight 24 located on the right side of the center point G. The mass of the body and the mass of the eccentric rotating body consisting of the eccentric portion 14b located on the left side from the center point G, the external gear 16b, and the counterweight 24 are made equal, and the eccentric portion 14a located on the right side from the center point G An axial distance from the center of gravity to the center point G of the eccentric rotating body composed of the gear 16a and the counterweight 24 and a radial distance from the center point to the rotational center, an eccentric portion 14b located on the left side from the center point G, an external gear 16b and a counter The right-side eccentric rotator is configured such that the axial distance from the center of gravity to the center point G of the eccentric rotator comprising the weight 24 and the radial distance to the rotation axis are equal. Couple according to the eccentric rotation of the left eccentric rotor is configured as canceled.

  The power transmission device shown in the embodiment has the above-described structure. When the rotary shaft 11 is rotated, the eccentric portions 14a and 14b rotate eccentrically, and the external gears 16a and 16b rotatably supported by the eccentric portions 14a and 14b. Revolves around the rotating shaft 11 while meshing with the internal teeth 18 formed on the inner periphery of the casing 1 one by one.

  At this time, since the number of external teeth 17 of the external gears 16 a and 16 b is smaller than the number of internal teeth 18 formed on the inner periphery of the casing 1, the external gears 16 a and 16 b per internal rotation 18 of the rotary shaft 11. And the number of teeth of the outer teeth 17 rotate in the direction opposite to the rotation direction of the rotary shaft 11, and the rotation motion is transmitted to the inner member 3 via the torque transmission means 20, and the inner member 3 rotates at a reduced speed.

Here, when the number of teeth of the internal teeth 18 is Z ₁ and the number of teeth of the external gears 16 a and 16 b is Z ₂ , the reduction ratio can be expressed by (Z ₁ −Z ₂ ) / Z ₂ .

  As described above, in the power transmission device shown in the embodiment, the external gears 16 a and 16 b meshed with the internal teeth 18 by the rotation of the rotary shaft 11 cause the internal teeth 18 and the external teeth 17 per rotation of the rotary shaft 11. Since the rotation of the rotary shaft 11 is reversed in the direction opposite to the rotation direction of the rotary shaft 11 and the rotation motion is transmitted to the inner member 3 via the torque transmission means 20, the rotation of the rotary shaft 11 is caused with a large reduction ratio. It can be transmitted to the inner member 3.

  In addition, since the speed reducer has a small number of parts including the external gears 16a and 16b and the internal teeth 18 formed on the inner periphery of the casing 1, a small and compact power transmission device can be obtained.

  As shown in FIG. 5, when the rotary shaft 11 is rotated by the electric motor 30 connected to the shaft end portion, a small and light in-wheel motor drive device can be formed.

  The stator 31 and the rotor 32 of the electric motor 30 may be incorporated in the casing 1.

  As described above, the control of the power transmission device that rotates the rotating shaft 11 with the electric motor 30 is performed, for example, between an accelerator pedal position sensor, a brake depression amount sensor, a vehicle speed sensor, a battery temperature detection sensor, and a battery terminal. Signals from various sensors, such as connected voltage sensors, current sensors installed in the power line from the battery, and rotational position detection sensors of the motor, are input to the electronic control unit, and on the basis of these signals, the inverter is connected. This is done by adjusting the power exchanged between the battery and the electric motor.

  For the control, for example, the number of rotations of the wheels driven by the power transmission device installed at each of the left and right or front and rear, left and right positions is independently controlled according to the steering angle of the steering wheel, thereby turning the vehicle stably. Or the idling of the wheel is detected from the signals of the wheel speed sensors of the front and rear wheels, and the rotational speed of the power transmission device is controlled based on the detection result to stabilize the posture of the vehicle.

A longitudinal front view showing an embodiment of a power transmission device according to the present invention Sectional drawing which expands and shows the eccentric part provided in the rotating shaft of FIG. Sectional view along line III-III in FIG. Sectional drawing which expands and shows a part of FIG. Longitudinal front view showing another embodiment of the power transmission device according to the present invention

Explanation of symbols

1 Casing (outer member)
2 Race surface 3 Inner member 4 Hub wheel 5 Bearing inner ring 5a Tube portion 6 Wheel mounting flange 7 Race surface 8 Race surface 10 Rolling body 11 Rotating shaft 14a Eccentric portion 14b Eccentric portion 16a External gear 16b External gear 17 External tooth 18 Internal Tooth 18a Outer pin 18b Roller 20 Torque transmission means 21 Inner pin 22 Roller 23 Circular hole 24 Counterweight 30 Electric motor 32 Rotor

Claims (8)

An outer member attached to the vehicle body and having a double-row raceway surface formed on the inner periphery of the end on the outboard side;
An inner side having a double-row raceway surface radially opposite to the double-row raceway surface of the outer member and a wheel mounting flange formed on an outer periphery of an end located outside the outer member A member,
A double row rolling element incorporated between a double row raceway surface of the outer member and a double row raceway surface of the inner member;
A rotating shaft that is arranged coaxially with the inner member and in which an eccentric portion is formed in a portion located inside the outer member;
An external gear that is rotatably supported by the eccentric portion of the rotating shaft and meshes with the internal teeth provided on the inner periphery of the outer member, and an external gear having a smaller number of teeth than the internal teeth;
Torque transmission means provided between the outer gear and the inner member, free to revolve the outer gear accompanying the eccentric rotation of the eccentric portion, and transmit the rotation motion to the inner member;
A power transmission device comprising:   The inner member has a hub wheel having a wheel mounting flange on the outer periphery, and a cylindrical portion that is inserted into the hub wheel and joined and integrated with the hub wheel by expanding and squeezing from the inner diameter portion. The power transmission device according to claim 1, comprising a bearing inner ring at an end of the bearing.   The power transmission device according to claim 1 or 2, wherein external teeth formed on an outer periphery of the external gear have a trochoidal curve tooth shape, and internal teeth formed on an inner periphery of the outer member include an external pin.   The power transmission device according to any one of claims 1 to 3, wherein a counterweight is attached to the rotating shaft such that the center of gravity of the counterweight is shifted in a circumferential direction by 180 ° with respect to the eccentric direction of the eccentric portion.   The power transmission device according to any one of claims 1 to 4, wherein two eccentric portions that rotatably support the external gear are provided, and the two eccentric portions are provided with a 180 ° phase shift in the circumferential direction.   The torque transmission means is provided with a plurality of inner pins on a concentric circle at equal intervals on one of the opposing surfaces facing the outer gear and the inner member in the axial direction, and each inner pin is formed on the other of the opposing surfaces. The power transmission device according to any one of claims 1 to 5, wherein the power transmission device has a configuration in which each inner pin is brought into contact with a part of the inner periphery of each circular hole by being inserted into a circular hole having a diameter larger than the diameter.   The power transmission device according to claim 6, wherein a roller is rotatably fitted to the inner pin, and the roller is brought into contact with a part of the inner periphery of the circular hole.   The power transmission device according to claim 1, wherein a rotor of an electric motor for rotational driving is connected to the rotating shaft.

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