JP6254489B2 - Power transmission mechanism - Google Patents

Description

  The present invention relates to a power transmission mechanism.

  Conventionally, a power transmission mechanism that transmits power from a power unit to a rear wheel using a drive shaft is known (see, for example, Patent Document 1). In Patent Document 1, by providing a damper between the ring gear driven by the drive shaft and the rear wheel axle, the transmission force felt by the driver can be reduced by reducing the torque transmitted from the power unit directly to the rear wheel. The ring is improved.

Japanese Utility Model Publication No. 2-105085

However, in the conventional power transmission mechanism, the size of the power transmission mechanism increases in the vehicle width direction by the amount of the damper provided, and the shape of the peripheral portion of the rear wheel or the like may be restricted. For this reason, it is desired to make the power transmission mechanism compact in the vehicle width direction.
The present invention has been made in view of the above-described circumstances, and in a power transmission mechanism including a drive shaft, the power transmission mechanism can be improved and the power transmission mechanism can be configured compactly in the vehicle width direction. The purpose is to do.

To achieve the above object, the present invention provides a drive shaft (22) for transmitting power from a power unit (11), a bevel gear (35) provided at the rear of the drive shaft (22), and the bevel gear (35). A ring gear (50) provided coaxially with the rear wheel (3), a rear wheel axle (47) coupled to the ring gear (50), at least the ring gear (50) and the bevel gear (35). In the power transmission mechanism including a gear case (24) for housing the damper, the damper mechanism (36) is provided on the power transmission path between the shaft body (31) of the drive shaft (22) and the bevel gear (35), the damper mechanism (36) is housed in the gear case (24) in the damper mechanism (36), said shaft body (31 A drive-side member (85) coupled to the rear end portion, a passive-side member (86) coupled to the bevel gear (35), and a drive-side disk portion (91) of the drive-side member (85). Each disk part (91) (93) is interposed between the drive side accommodating part (91a) and the passive side accommodating part (93a) of the passive side disk part (93) of the passive side member (86). is compressed in the circumferential direction and a spring member (87) for receiving a load of the gear case (24) is characterized Rukoto filled with oil.

Further, according to the present invention, the drive side member (85) and the passive side member (86) are arranged coaxially and arranged so as to overlap in the radial direction of the shaft, and the drive side member (85) It is fitted to the passive side member (86) through a bush (88).
The present invention further includes a bearing (70) for supporting the bevel gear (35) on the gear case (24), and the bearing (70) includes the passive side member (86) and the bevel gear (35). It is characterized by being sandwiched.

In the power transmission mechanism according to the present invention, a damper mechanism is provided on the power transmission path between the shaft main body of the drive shaft and the bevel gear, and the damper mechanism is accommodated in the gear case. Thereby, a damper mechanism can be provided using the space on the power transmission path between the drive shaft and the bevel gear, and the size of the power transmission mechanism in the vehicle width direction can be suppressed. For this reason, while being able to improve the power transmission feeling, a power transmission mechanism can be comprised compactly in the vehicle width direction.
In addition, the damper mechanism includes a spring member interposed between the driving side member and the passive side member, and the mechanical spring member can be lubricated with oil in the gear case, so that the damper mechanism operates smoothly. be able to.

Further, since the driving side member and the passive side member are fitted together via the bush, the friction between the driving side member and the passive side member can be reduced by the bush, and the damper mechanism can be operated smoothly.
Furthermore, the passive side member and the bevel gear can be fixed to the bearing by sandwiching the bearing that supports the bevel gear in the gear case between the passive side member and the bevel gear, and the passive side member and the bevel gear can be fixed with a simple configuration.

It is a left side view showing the rear part of the motorcycle provided with the power transmission mechanism according to the embodiment of the present invention. It is II-II sectional drawing of FIG. It is an enlarged view of the internal structure of the gear case of FIG. It is an enlarged view of the internal structure of the bevel gear accommodating part of FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description, descriptions of directions such as front and rear, right and left and up and down are the same as directions with respect to the vehicle body unless otherwise specified. Also, in each figure, the symbol FR indicates the front of the vehicle body, the symbol UP indicates the vehicle body upper side, and the symbol L indicates the left side of the vehicle body.

FIG. 1 is a left side view showing a rear portion of a motorcycle 10 provided with a power transmission mechanism according to an embodiment of the present invention. Here, FIG. 1 shows a cross section of the vehicle body frame F at the center in the vehicle width direction.
In the motorcycle 10, an engine 11 as a power unit is supported on a body frame F, a front fork (not shown) that supports a front wheel (not shown) is supported by a front end of the body frame F so as to be steerable, and a rear wheel 3 is suspended. The swing arm 12 is a vehicle provided at the rear part of the body frame F. The motorcycle 10 is a saddle-ride type vehicle in which a seat (not shown) on which an occupant sits is supported on an upper portion of a rear portion of a vehicle body frame F.

  The vehicle body frame F includes a front end head pipe (not shown) that pivotally supports the front fork, a pair of left and right main frames 13 extending rearward from the headed pipe, and a lower side from the rear end of the main frame 13. And a pair of left and right center frames 14 and a seat frame (not shown) extending rearward from the upper portion of the center frame 14.

The swing arm 12 is pivotally supported at a front end by a pivot shaft 15 inserted through upper and lower intermediate portions of the left and right center frames 14, and can swing around the pivot shaft 15.
The lower end of the rear cushion 16 is connected to a link mechanism 17 provided across the swing arm 12 and the center frame 14. The upper end of the rear cushion 16 is connected to a cross member 18 that connects the left and right center frames 14 in the vehicle width direction.

2 is a cross-sectional view taken along the line II-II in FIG. In FIG. 2, the rear cushion 16 and an arm cover 19 to be described later are not shown.
The engine 11 includes an output shaft 21 that extends straight rearward from the rear side of the crankcase 20. The motorcycle 10 is a shaft drive type vehicle in which the output of the output shaft 21 is transmitted to the rear wheel 3 via the drive shaft 22.
The swing arm 12 includes a swing arm main body 23 that is supported by the pivot shaft 15 and extends rearward, and a gear case 24 that is coupled to the rear end 23 a of the swing arm main body 23 and supports the rear wheel 3. The joint between the swing arm main body 23 and the gear case 24 is covered with an arm cover 19.

The swing arm body 23 includes a front cylindrical portion 25 through which the pivot shaft 15 is inserted, an arm portion 26 that extends rearward from one end of the front cylindrical portion 25 toward one side of the rear wheel 3, and a front cylindrical portion 25. A reinforcing arm portion 27 that extends rearward from the other end, bends, and is coupled to the front and rear intermediate portions of the arm portion 26 is provided.
The arm portion 26 includes a hollow portion 26a extending over the entire length thereof, and the drive shaft 22 is accommodated in the hollow portion 26a.

The gear case 24 is provided with a speed reduction mechanism 28 that decelerates the rotation of the drive shaft 22 and transmits it to the rear wheel 3.
A brake caliper 29 is provided at the rear of the swing arm 12. The rear wheel 3 is braked when a brake disc 30 b provided on the hub 30 a of the wheel 30 of the rear wheel 3 is sandwiched between brake calipers 29.

Referring to FIGS. 1 and 2, the output shaft 21 is positioned below the pivot shaft 15, and the drive shaft 22 extends rearward through the hollow portion 26 a below the pivot shaft 15 and is connected to the speed reduction mechanism 28. .
The drive shaft 22 includes a shaft body 31, a bevel gear 35 provided at the rear portion of the drive shaft 22 and connected to the speed reduction mechanism 28, and a damper mechanism provided on a power transmission path between the shaft body 31 and the bevel gear 35. 36.
The shaft body 31 includes a universal joint portion 32 connected to the output shaft 21, a shaft portion 33 passing through the hollow portion 26 a, and a constant velocity joint portion 34 provided at the rear end of the shaft portion 33. Specifically, the damper mechanism 36 is interposed between the constant velocity joint portion 34 and the bevel gear 35.

The drive shaft 22 is rotatable while swinging up and down around the universal joint portion 32, and is disposed obliquely so that the rear side is located on the outer side in the vehicle width direction with the universal joint portion 32 as a base point. .
The constant velocity joint portion 34 includes a tripod type input shaft 37, a cup 38 into which the input shaft 37 is fitted, and a cover 39 that closes the opening of the cup 38. The input shaft 37 is relatively movable in the axial direction within the cup 38 while transmitting power to the cup 38.

FIG. 3 is an enlarged view of the internal structure of the gear case 24 of FIG.
The gear case 24 includes a gear case main body 40 coupled to the rear end 23 a of the swing arm main body 23, and a case cover 41 fixed to the inner side surface of the gear case main body 40.
The gear case main body 40 has a bevel gear housing portion 42 opening forward at the front portion and a case side housing portion 43 penetrating in the vehicle width direction at the rear portion.
The case cover 41 is formed in a cylindrical shape extending in the vehicle width direction, and includes a cover side accommodation portion 44 that communicates with the case side accommodation portion 43 on the inner side. Axle housing part 45 is formed by combining case side housing part 43 and cover side housing part 44 together. The case cover 41 is fastened to the gear case body 40 by a plurality of bolts 46.

The axle housing 45 includes a rear wheel axle 47 that supports the rear wheel 3, a bearing 48 that supports one end of the rear wheel axle 47, a bearing 49 that supports the other end of the rear wheel axle 47, and a rear wheel axle 47. And a ring gear 50 that meshes with the bevel gear 35 is provided.
The bearing 48 is provided in the case side accommodating portion 43. The bearing 49 is provided in the cover side accommodating portion 44. The bearings 48 and 49 are ball bearings.
The rear wheel axle 47 is a rotating shaft that extends in the vehicle width direction so as to be orthogonal to the axial direction of the bevel gear 35. The rear wheel axle 47 includes a small diameter part 51 supported by the bearing 48, a large diameter part 52 having a larger diameter than the small diameter part 51 and supported by the bearing 49, and a small diameter part 51 and a large diameter part 52 in the axial direction. And a ring gear support portion 53 having a smaller diameter than the large diameter portion 52.

The ring gear 50 is a ring-shaped bevel gear provided coaxially with the rear wheel axle 47, and is fixed integrally to the rear wheel axle 47 by spline fitting to the outer periphery of the ring gear support portion 53. The number of teeth of the ring gear 50 is larger than the number of teeth of the bevel gear 35.
The outer race 48 a of the bearing 48 is fixed to the case side housing portion 43 by a lock nut 54 that is tightened into the case side housing portion 43. The inner race 48 b of the bearing 48 is fixed to the rear wheel axle 47 by a lock nut 55 that is fastened to the end of the small diameter portion 51. The opening of the case side accommodating portion 43 that exposes the lock nuts 54 and 55 to the outside is closed by a cap 56 fastened to the opening.

A flange member 57 is provided on the end surface 52 a of the large-diameter portion 52 of the rear wheel axle 47. The flange member 57 includes a ring-shaped disc portion 58 and a cylindrical portion 59 that protrudes from the center portion of the disc portion 58 to the inside of the axle housing portion 45. The cylindrical portion 59 is provided coaxially with the disc portion 58.
The flange member 57 is fixed to the end surface of the large-diameter portion 52 by a bolt 60 inserted into the disc portion 58 from the surface on the hub 30a side with the cylindrical portion 59 fitted to the outer peripheral portion of the end portion of the large-diameter portion 52. The A space between the cylindrical portion 59 and the case cover 41 is sealed with a ring-shaped oil seal 66.

The inner race 49 b of the bearing 49 is fixed to the rear wheel axle 47 by being sandwiched between the flange portion 52 b of the large diameter portion 52 and the tip of the cylindrical portion 59. The brake disc 30 b is fixed to the peripheral portion of the disc portion 58 with a disc fixing bolt 61.
The wheel 30 is disposed so as to sandwich the flange member 57 between the hub 30a and the end surface 52a of the rear wheel axle 47, and is fixed to the large-diameter portion 52 by a plurality of wheel fixing bolts 62 penetrating the hub 30a and the flange member 57. .
The swing arm 12 is a cantilever type in which the rear wheel 3 is supported only by the arm portion 26 on one side of the rear wheel 3.

FIG. 4 is an enlarged view of the internal structure of the bevel gear housing portion 42 of FIG.
The bevel gear accommodating portion 42 is formed in a substantially cylindrical shape having a front surface with an opening 42a, and includes a cylindrical space inside.
The bevel gear accommodating portion 42 includes a bevel gear 35, a damper mechanism 36, a bearing 70 that supports the damper mechanism 36, a lock nut 71 that fixes the bearing 70, a seal member 72 that seals the bevel gear accommodating portion 42, and the bevel gear 35. And a rear end support bearing 73 is provided.

The bevel gear accommodating portion 42 has a bearing support hole 74 in the rear wall surface, and a rear end support bearing 73 is provided in the bearing support hole 74. In addition, a communication portion 75 that communicates the bevel gear accommodation portion 42 with the axle accommodation portion 45 is provided on the rear side wall of the bevel gear accommodation portion 42, and the bevel gear 35 and the ring gear 50 are engaged with each other at the communication portion 75. The rear wheel 3 is rotated integrally with the rear wheel axle 47 by the driving force transmitted from the bevel gear 35 to the rear wheel axle 47 via the ring gear 50.
The bevel gear housing portion 42 includes a front housing portion 76 that is continuous with the hollow portion 26a of the swing arm 12 through the opening 42a, and a bearing housing portion 77 that is formed behind the front housing portion 76 and has a smaller diameter than the front housing portion 76. And a rear housing part 78 behind the bearing housing part 77.

  The bearing accommodating portion 77 includes a flange-shaped flange portion 77a that protrudes inward. The outer race 70 a of the bearing 70 is fitted into the bearing housing portion 77 and is sandwiched between the lock nut 71 and the flange portion 77 a that are fastened to the inner peripheral portion of the bearing housing portion 77, so that the gear case main body 40 is engaged. Fixed. The position of the outer race 70a can be finely adjusted by a shim 77b provided between the flange portion 77a and the outer race 70a. The bearing 70 is an angular ball bearing capable of receiving both axial and radial loads.

The bevel gear 35 includes an umbrella-shaped tooth portion 79, a support shaft portion 80 that protrudes rearward from the center portion of the rear surface of the tooth portion 79, and a connection that protrudes forward from the front surface 79a of the tooth portion 79 coaxially with the support shaft portion 80. A shaft portion 81 is provided. The connecting shaft portion 81 includes a female screw portion 83 to which a damper mechanism fixing bolt 82 for fixing the damper mechanism 36 is fastened.
The bevel gear 35 is disposed in the rear housing portion 78, and is supported rotatably by the support shaft portion 80 being fitted to the inner peripheral portion of the rear end support bearing 73.

  As shown in FIGS. 3 and 4, the damper mechanism 36 includes a driving side member 85 coupled to the cup 38 of the constant velocity joint portion 34, a passive side member 86 coupled to the bevel gear 35, and a driving side member 85. A plurality of spring members 87 interposed between the passive side member 86 and a cylindrical bush 88 provided at a sliding portion between the driving side member 85 and the passive side member 86 are provided. The spring member 87 is a metal coil spring.

In the bevel gear housing portion 42, the opening 42 a is closed by fitting a disc-shaped seal member 72 into the inner peripheral portion. The seal member 72 has a hole 72a in the center. The position of the seal member 72 is regulated by a ring-shaped clip 65 that fits in the inner peripheral portion of the bevel gear housing portion 42.
The cup 38 of the constant velocity joint portion 34 includes a connecting shaft 38 a that protrudes rearward from the center portion of the rear surface of the cup 38. The connecting shaft 38a includes a fixed portion 38b having a smaller diameter than the base end portion at the distal end portion, and the drive side member 85 is fixed to the fixed portion 38b. The drive side member 85 contacts the stepped portion 38c of the connecting shaft 38a and is positioned in the axial direction.
The connecting shaft 38 a is inserted into the hole 72 a of the seal member 72 and enters the bevel gear accommodating portion 42, and the driving side member 85 is coupled to the fixed portion 38 b within the bevel gear accommodating portion 42.

  The drive side member 85 includes a cylindrical portion 90 that is spline-fitted to the outer peripheral portion of the fixed portion 38b of the connecting shaft 38a, and a drive side disc portion 91 that extends radially outward from the front end of the cylindrical portion 90. Since the driving side member 85 is fixed to the fixing portion 38b by spline fitting, the driving side member 85 rotates integrally with the shaft body 31. A bush 88 is fitted to the outer peripheral portion of the cylindrical portion 90. As the bush 88, for example, a ball bearing, a porous bearing that easily holds oil, or an oil-free bush (bearing) is used.

The passive side member 86 includes an outer cylindrical portion 92 that surrounds the cylindrical portion 90 of the driving side member 85 from the outside, and a passive-side disc portion 93 that extends radially outward from the front end of the outer cylindrical portion 92.
The outer cylindrical portion 92 of the passive side member 86 includes a bush fitting portion 92a fitted to the outer peripheral portion of the bush 88, a bearing fitting portion 92b having a smaller outer diameter than the bush fitting portion 92a, and a bush fitting portion. An annular step 92c between the bearing 92a and the bearing fitting 92b. The bearing fitting portion 92b has a fixing hole portion 92d that is spline fitted to the outer peripheral portion of the connecting shaft portion 81 of the bevel gear 35 on the inner peripheral portion. The inner diameter of the fixed hole portion 92d is smaller than the inner diameter of the bush fitting portion 92a.

The passive member 86 is coupled to the bevel gear 35 by the spline fitting of the connecting shaft portion 81 of the bevel gear 35 to the fixed hole portion 92d, and can be rotated integrally with the bevel gear 35. The passive side member 86 is fixed in the axial direction by the damper mechanism fixing bolt 82 that is passed through the outer cylindrical portion 92 and fastened to the female screw portion 83.
Further, the passive member 86 is supported by the bearing 70 when the bearing fitting portion 92 b is fitted to the inner peripheral portion of the inner race 70 b of the bearing 70. Specifically, the passive member 86 and the bevel gear 35 are coupled to the inner race 70b by sandwiching the inner race 70b between the step portion 92c and the front surface 79a of the tooth portion 79 by the fastening force of the damper mechanism fixing bolt 82. . That is, the passive side gear portion 94, which is a combined body of the passive side member 86 and the bevel gear 35, is supported in the bevel gear housing portion 42 via the bearing 70 and the rear end support bearing 73.

The drive side member 85 and the passive side member 86 can rotate relative to each other when the cylindrical portion 90 and the outer cylindrical portion 92 are fitted via the bush 88. In addition, the driving side disc portion 91 and the passive side disc portion 93 are provided to face each other so as to contact each other, and a spring member 87 is provided between the driving side disc portion 91 and the passive side disc portion 93. A cylindrical spring accommodating portion 95 that accommodates the above is provided. A plurality of spring accommodating portions 95 are provided at substantially equal intervals in the radial direction of the driving side disc portion 91 and the passive side disc portion 93.
Each spring accommodating portion 95 is formed by combining a driving side accommodating portion 91 a provided in the driving side disc portion 91 and a passive side accommodating portion 93 a provided in the passive side disc portion 93. In the sectional view in the circumferential direction of the driving side disc portion 91, the driving side accommodating portion 91a is a substantially semicircular recess. In the cross-sectional view of the passive side disc portion 93 in the circumferential direction, the passive side accommodation portion 93a is a substantially semicircular recess.

In each spring member 87, one end of the coil shape abuts against the wall portion of the drive side accommodation portion 91a, the other end of the coil shape abuts against the wall portion of the passive side accommodation portion 93a, and the drive side disk portion 91 and the passive side A load that is compressed in the circumferential direction of the disc portion 93 is received. That is, for example, when the rotation on the shaft body 31 side increases, the drive side member 85 rotates relative to the passive side member 86 while compressing and deforming each spring member 87, and the power of the shaft body 31 is elastically deformed. It is transmitted to the bevel gear 35 side through the spring member 87. For this reason, fluctuations in power transmission that occur between the engine 11 and the rear wheel 3 can be reduced by the damper action of the damper mechanism 36.
Here, the damper mechanism 36 is provided with a stopper portion (not shown) that restricts the deformation amount of each spring member 87, and an excessive load is prevented from acting on each spring member 87.

In the present embodiment, the damper mechanism 36 is provided in the bevel gear accommodating portion 42 using the space in the axial direction of the drive shaft 22 in the power transmission path between the shaft body 31 and the bevel gear 35. The power transmission mechanism provided with 36 can be provided compactly in the width direction of the gear case 24.
The gear case 24 is filled with oil that lubricates the bevel gear 35, the ring gear 50, the bearing 70, and the like. In the present embodiment, since the spring member 87 is a metal mechanical spring, the spring member 87 can be lubricated with the oil, and the damper mechanism 36 can be operated smoothly. At the front end of the gear case 24, the oil is sealed with a seal member 72.

Here, an assembling procedure of the bevel gear 35 and the damper mechanism 36 will be described.
First, the bevel gear 35 is disposed in the rear housing portion 78 and supported by the rear end support bearing 73. Next, the shim 77 b and the bearing 70 are disposed in the bearing housing portion 77, and the outer race 70 a is fixed by the lock nut 71.
Next, the bearing fitting portion 92b of the passive member 86 is inserted into the bearing 70, the bearing fitting portion 92b is fitted into the inner race 70b, and the fixed hole portion 92d is fitted into the connecting shaft portion 81 of the bevel gear 35. Then, the damper mechanism fixing bolt 82 is fastened.
Subsequently, after the bush 88 and the spring member 87 are set on the passive member 86, the drive member 85 is assembled to the passive member 86 via the bush 88.
In the present embodiment, since the passive side gear portion 94 is divided into the bevel gear 35 and the passive side member 86, the outer diameters of the driving side disc portion 91 and the passive side disc portion 93 are larger than the lock nut 71. Even with such a configuration, the lock nut 71 can be assembled. For this reason, the drive side disk part 91 and the passive side disk part 93 can be made large-diameter, and the capability of the damper mechanism 36 can be increased.

  As described above, according to the embodiment to which the present invention is applied, the power transmission mechanism includes the drive shaft 22 that transmits power from the engine 11, the bevel gear 35 provided at the rear portion of the drive shaft 22, and the bevel gear 35. , And a rear wheel axle 47 coupled to the ring gear 50, and a gear case 24 accommodating at least the ring gear 50 and the bevel gear 35, and a shaft of the drive shaft 22. A damper mechanism 36 is provided on the power transmission path between the main body 31 and the bevel gear 35, and the damper mechanism 36 is accommodated in the gear case 24. Thereby, the damper mechanism 36 can be provided by utilizing the space on the power transmission path between the drive shaft 22 and the bevel gear 35, and the size of the gear case 24 of the power transmission mechanism in the vehicle width direction can be suppressed. For this reason, power transmission feeling can be improved and the gear case 24 can be configured compactly in the vehicle width direction.

  The damper mechanism 36 is interposed between the driving side member 85 coupled to the rear end portion of the shaft body 31, the passive side member 86 coupled to the bevel gear 35, and the driving side member 85 and the passive side member 86. And a spring member 87. For this reason, the mechanical spring member 87 can be lubricated with the oil in the gear case 24, and the damper mechanism 36 can be operated smoothly.

The driving side member 85 and the passive side member 86 are arranged coaxially and are arranged so as to overlap in the radial direction of the shaft, and a bush 88 is interposed between the driving side member 85 and the passive side member 86. Fitted together. For this reason, the friction between the drive side member 85 and the passive side member 86 can be reduced by the bush 88, and the damper mechanism 36 can be operated smoothly.
Furthermore, a bearing 70 that supports the bevel gear 35 on the gear case 24 is provided, and the bearing 70 is sandwiched between the passive member 86 and the bevel gear 35. Therefore, by sandwiching the bearing 70 between the passive member 86 and the bevel gear 35, the passive member 86 and the bevel gear 35 can be fixed to the bearing 70, and the passive member 86 and the bevel gear 35 can be fixed with a simple configuration.

In addition, the said embodiment shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said embodiment.
In the above embodiment, the engine 11 is described as an example of the power unit. However, the present invention is not limited to this, and for example, the power unit may be an electric motor.
In the above embodiment, the damper mechanism 36 has been described as including the spring member 87. However, the present invention is not limited to this. For example, a resin block-like elastic member may be used instead of the spring member 87. .

3 Rear wheels 11 Engine (power unit)
22 Drive shaft 24 Gear case 31 Shaft body 35 Bevel gear 36 Damper mechanism 47 Rear wheel axle 50 Ring gear 70 Bearing (bearing that supports the bevel gear on the gear case)
85 Drive side member 86 Passive side member 87 Spring member 88 Bush

Claims (3)

A drive shaft (22) for transmitting power from the power unit (11), a bevel gear (35) provided at the rear of the drive shaft (22), and meshed with the bevel gear (35) and coaxially with the rear wheel (3) A ring gear (50) provided; a rear wheel axle (47) coupled to the ring gear (50); and a gear case (24) for accommodating at least the ring gear (50) and the bevel gear (35). In the power transmission mechanism,
A damper mechanism (36) is provided on a power transmission path between the shaft main body (31) of the drive shaft (22) and the bevel gear (35), and the damper mechanism (36) is disposed in the gear case (24). The damper mechanism (36) is accommodated, and includes a drive side member (85) coupled to a rear end portion of the shaft body (31), a passive side member (86) coupled to the bevel gear (35), A drive side accommodation portion (91a) of the drive side disc portion (91) of the drive side member (85), and a passive side accommodation portion (93a) of the passive side disc portion (93) of the passive side member (86). interposed between said a respective disc portion (91) a spring member for receiving a load is compressed in the circumferential direction of the (93) (87), the Rukoto filled with the gear case (24) oil A power transmission mechanism. The drive side member (85) and the passive side member (86) are arranged coaxially and are arranged so as to overlap in the radial direction of the shaft, and the drive side member (85) and the passive side member (86) are arranged. The power transmission mechanism according to claim 1 , wherein the power transmission mechanism is fitted through a bush. A bearing (70) for supporting the bevel gear (35) on the gear case (24) is provided, and the bearing (70) is sandwiched between the passive side member (86) and the bevel gear (35). The power transmission mechanism according to claim 1 or 2 .

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