Rear wheel unit, motor tricycle including the same and method for converting motorcycle into the motor tricycle

Abstract

To provide a rear wheel unit which can improve balance of a vehicle body and a motor tricycle including the rear wheel unit.SOLUTION: A rear wheel unit mounted to a motor tricycle includes: a support body; a differential gear case 3 rotatably supported by the support body; a sprocket which is mounted to the differential gear case and around which a chain transmitting power from a driving source is wound; a differential mechanism stored in the differential gear case; a pair of drive shafts 4 which have the same length and extend from the differential gear case to directions opposite to each other and to which rotation of the differential gear case is allocated by the differential mechanism; a pair of rear wheels connected to each drive shaft; and a pair of axle tubes 8 fixed to the support body, storing each drive shaft and having the same length.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rear wheel unit that is attached to a motor tricycle, a motor tricycle including the same, and a method for converting a motorcycle into a motor tricycle. [Background technology]

[0002] In recent years, three-wheeled motor vehicles called trikes, which have one front wheel and two rear wheels, have become popular. Trikes are sold as specially designed vehicles, but most are modified versions of commercially available motorcycles. For example, Patent Document 1 proposes a trike kit for converting a motorcycle into a three-wheeled motor vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3152937 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in the above Patent Document 1, when converting a motorcycle into a three-wheeled vehicle, the drive mechanism of the motorcycle is usually used, and for example, the rear axle of the rear wheel is attached to match the position of the chain that transmits the power from the drive source. In this case, in Patent Document 1, it is considered that the axle tubes are arranged so that the left and right sides are different in length as the position of the differential case is shifted from the center. Such an arrangement may cause the balance of the vehicle body to be poor, which may cause problems in driving. Note that such a balance of the vehicle body is an issue not only when converting a motorcycle into a three-wheeled vehicle, but also when designing a three-wheeled vehicle independently.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a rear wheel unit that can improve the balance of the vehicle body, a three-wheeled motor vehicle equipped with the same, and a method for converting a motorcycle into a three-wheeled motor vehicle. [Means for solving the problem]

[0006] The present invention provides a rear wheel unit that is attached to a three-wheeled vehicle (or trike), comprising: a support body; a differential case supported on the support body so as to be freely rotatable; a sprocket attached to the differential case and around which a chain that transmits power from a drive source is wound; a differential mechanism housed in the differential case; a pair of drive shafts of the same length that extend in opposite directions from the differential case and whose rotation is distributed by the differential mechanism; a pair of rear wheels connected to each of the drive shafts; and a pair of axle tubes of the same length that are fixed to the support body and in which the drive shafts are housed.

[0007] According to this configuration, a sprocket is attached to the differential case, and the power from the drive source is transmitted by a chain wound around the sprocket to rotate the differential case. A pair of drive shafts of the same length and a pair of axle tubes that house them are arranged at both ends of the differential case, so that the power from the drive source rotates the differential case. Therefore, the power to the rear wheels can be transmitted in a balanced manner between the left and right, and as a result, the balance of the vehicle body can be improved.

[0008] The differential case can have various configurations, but for example, it can be configured to be composed of first and second cup-shaped case members that house the differential mechanism, and the opening edge of the first case member fits into the inner peripheral surface of the opening edge of the second case member to form the differential case. A sprocket can be attached to the end face of the opening edge of the second case.

[0009] According to this configuration, the differential case is formed of first and second cup-shaped case members, and when the first case member is fitted into the second case member, the end face of the opening edge of the second case member is exposed in the axial direction. Therefore, the end face can be used to attach the sprocket, so there is no need to separately prepare a flange for attaching the sprocket, and the differential case can be made compact. The sprocket can be formed, for example, with a bolt.

[0010] The differential mechanism housed in the differential case can be in various forms, but for example, it can include a pinion shaft rotatably connected to the differential case, a pair of pinion gears attached to both ends of the pinion shaft, and a pair of side gears that mesh with each pinion gear and are connected to each drive shaft.

[0011] In this case, the differential case can be formed by first and second cup-shaped case members that house the differential mechanism, and the opening edge of the second case member can be fitted into the inner peripheral surface of the opening edge of the first case member to form the differential case. A through hole through which the pinion shaft is rotatably inserted can be formed in the opening edge of the second case member, and both through holes can be blocked by the opening edge of the first case member. This can prevent the lubricating oil filled in the differential case from leaking from the through holes.

[0012] In addition, the above-mentioned rear wheel unit can further be provided with a hub damper attached to one axial end of the differential case to buffer the power transmitted to the differential case and to which the sprocket is fixed, and a drum brake attached to the other axial end of the differential case.

[0013] With this configuration, the sprockets are attached to the differential case via the hub dampers, so that sudden chain transmission can be cushioned. In addition, a drum brake is attached to the other end of the differential case, so that braking can also be performed. Since such hub dampers and drum brakes can be those normally provided on motorcycles, when converting a motorcycle into a three-wheeled vehicle, the ones provided on the motorcycle can be attached to the differential case as is and used. Therefore, for example, when it is desired to return a three-wheeled vehicle to a motorcycle, the hub dampers and drum brakes can be removed from the differential case and used as is for the motorcycle.

[0014] The present invention also provides a three-wheeled motor vehicle including the above-mentioned rear wheel unit.

[0015] The present invention also provides a method for converting a motorcycle into a three-wheeled motorcycle, comprising a preparation step of preparing the above-mentioned rear wheel unit, a removal step of removing the rear wheel from the motorcycle, and an attachment step of attaching the rear wheel unit to a rear end of the motorcycle, wherein in the attachment step, a chain extending from a drive source of the motorcycle is wound around a sprocket of the rear wheel unit.

[0016] According to this configuration, when converting a motorcycle into a three-wheeled vehicle, a pair of drive shafts of the same length and a pair of axle tubes that house them are attached to both ends of the differential case, and the differential case is rotated by the power from the drive source. Therefore, the driving force can be transmitted to the rear wheels in a balanced manner, and as a result, the balance of the vehicle body can be improved. The chain may be one that was installed on the motorcycle, or a new one may be prepared.

[0017] The above method further includes a step of removing the hub damper and drum brake provided on the motorcycle prior to mounting the rear wheel unit, and in the preparation step, a sprocket is attached to the hub damper, the hub damper is attached to one axial end of the differential case, and the drum brake is attached to the other axial end of the differential case. In this way, the hub damper and drum brake provided on the motorcycle can be used as is. Note that either the attachment of the sprocket to the hub damper or the attachment of the hub damper to the differential case may be performed first. Effect of the Invention

[0018] According to the present invention, the balance of the vehicle body can be improved. [Brief description of the drawings]

[0019] [Figure 1] 1 is a perspective view showing a first embodiment of a rear wheel unit according to the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of the differential case of FIG. [Diagram 3] FIG. 4 is a perspective view showing a second embodiment of a rear wheel unit according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] (First embodiment) A first embodiment of a rear wheel unit according to the present invention applied to a scooter-type motorcycle will be described below with reference to the drawings. Fig. 1 is a perspective view showing the rear wheel unit. For ease of explanation, the direction in which the drive shaft of the differential case extends may be referred to as the axial direction, and the direction perpendicular to this may be referred to as the radial direction.

[0021] As shown in FIG. 1, this rear wheel unit is used for modifying a scooter-type motorcycle, and is attached after removing the rear wheel of the motorcycle. This rear wheel unit has a trike main frame 1 attached to the rear end of the motorcycle, and a support frame 2 attached to the rear end side of the main frame 1. This support frame 2 is composed of a pair of disk-shaped support blocks 21 arranged at a predetermined interval in the left-right direction, and a plurality of connecting rods 22 extending in the left-right direction and connecting these support blocks 21. A differential case 3 is rotatably attached between both support blocks 21. A bearing 23 is attached to each support block 21, and the bearing 23 allows the differential case 3 to rotate relative to the support blocks 21.

[0022] Next, the differential case 3 will be described with reference to FIG. 2. FIG. 2 is a cross-sectional view of the differential case. As shown in the figure, the differential case 3 is formed by fitting together a cup-shaped first case member 31 and a second case member 32. The inner diameter of the opening edge portion 311 of the first case member 31 is approximately the same as the outer diameter of the opening edge portion 321 of the second case member 32, and the opening edge portion 321 of the second case member 32 is press-fitted into the opening edge portion 311 of the first case member 31 to connect the two. At this time, although not shown in the figure, the two case members 31 and 32 can be connected by a spline connection. However, other known connection methods may be used. A gasket 61 is disposed between the opening edge portions 311 and 321 of the two case members 31 and 32 to prevent leakage of lubricating oil, which will be described later. Further, cylindrical bosses 312, 322 through which a drive shaft 4, which will be described later, is inserted are integrally provided at the axial end of each of the case members 31, 32 opposite to the opening.

[0023] The differential case 3 thus formed houses the following bevel gear type differential mechanism. First, through holes 323 through which the pinion shaft 33 is rotatably inserted are formed at radially opposing positions of the opening edge portion 321 in the second case member 32. Then, pinion gears 34 are attached to both ends of the inserted pinion shaft 33. Then, a pair of side gears 35 are arranged on both sides of the pinion gear 34, and each side gear 35 is meshed with the pinion gear 34. A drive shaft 4 is spline-coupled to each pinion gear 34, and these drive shafts 4 extend in the left-right direction through bosses 312, 322 of the case members 31, 32, respectively. The lengths of both drive shafts 4 are the same. Also, the openings of each boss 312, 322 are sealed with an oil seal 36 to prevent the lubricating oil filled in the differential case 3 from leaking. As described above, a through hole 323 for inserting the pinion shaft 33 is formed in the opening edge portion 321 of the second case member 32, but this through hole 323 is blocked by the opening edge portion 311 of the first case member 31, thereby preventing leakage of lubricating oil from the through hole 323.

[0024] A flange 313 is formed on the outer peripheral surface of the differential case 3, that is, on the outer peripheral surface of the opening edge portion 311 of the first case member 31, and a sprocket 5 is attached to this flange 313. A chain 6 extending from the engine is wound around this sprocket 5, as described later. The bosses 312, 322 of each case member 31, 32 are attached to the support block 21 via the above-mentioned bearing 23. A through hole leading to the inside is formed on the outer peripheral surface of the differential case 3, and lubricating oil is injected from here. The through hole is sealed with a bolt or a gasket 60.

[0025] Returning to FIG. 1, the rear wheel unit will be described further. A cylindrical axle tube 8 is attached to each support block 21 of the support frame 2 via a funnel-shaped bracket 7. Both axle tubes 8 have the same length and extend in the left-right direction. Bearings 81, 82 are attached to both ends of each axle tube 8, and these bearings 81, 82 rotatably support the drive shaft 4 that is inserted from the differential case 3 into the axle tube 8. The axle tube 8 is rotatably attached to the rear wheel via a hub (not shown). The tip of the drive shaft 4 protruding from each axle tube 8 is fixed to the rear wheel.

[0026] In the above rear wheel unit, the support frame 2, the axle tube 8, and the differential case 3 can be made of aluminum to reduce weight.

[0027] The rear wheel unit configured as described above operates as follows. When the engine starts, power is transmitted to the chain 6 via a transmission such as a CVT (not shown). The chain 6 rotates the differential case 3 together with the sprocket 5 about its axis, which in turn rotates the side gears 35, the drive shaft 4, and the wheels, driving the rear wheels. When a load is applied to any of the rear wheels, the pinion gear 34 rotates together with the pinion shaft 33, causing a differential operation.

[0028] According to the rear wheel unit configured as described above, the sprocket 5 is attached to the differential case 3, and the power from the engine is transmitted by the chain 6 wound around the sprocket 5 to rotate the differential case 3. A pair of drive shafts 4 having the same length and a pair of axle tubes 8 that accommodate them are arranged at both ends of the differential case 3, and the differential case 3 is rotated around its axis by the power from the engine. Therefore, even when a motorcycle is modified to become a three-wheeled motor vehicle, the driving force to the rear wheels can be transmitted in a balanced manner, and as a result, the balance of the vehicle body can be improved. In particular, the chain 6 extending from the engine extends along approximately the center in the lateral direction of the vehicle body, and is wound around the sprocket 5 attached to approximately the center of the differential case 3, so that the power can be transmitted in a balanced manner.

[0029] Second embodiment Next, a second embodiment in which a rear wheel unit according to the present invention is applied to a manual type motorcycle will be described with reference to Fig. 3. Fig. 3 is a perspective view showing the second embodiment.

[0030] As shown in FIG. 3, this rear wheel unit has a trike support frame 10 attached to the rear end of a motorcycle, similar to the first embodiment. This support frame 10 has a pair of rectangular support plates 101 arranged at a predetermined interval, and these support plates 101 are connected by a plurality of connecting rods 102. In addition, in order to reinforce the connecting rods 102, the plurality of connecting rods 102 are reinforced by a reinforcing rod 103 extending in the front-rear direction of the vehicle body. Inside this support frame 10, a differential case 30 is arranged. This differential case 30 differs from that of the first embodiment in that no flange is attached to the outer peripheral surface, but the other points are generally the same. A known hub damper 9 is attached to the left side in the axial direction of this differential case 30. The hub damper 9 is a known one, and although not shown, a cushioning material having rubber, springs, etc. is arranged inside a circular hub, and the differential case 3 is fixed to these cushioning materials via a bracket. A sprocket 52 is attached to the outer peripheral surface of the hub of the hub damper 9. On the other hand, a well-known drum brake 104 is connected to the right side of the differential case 30 in the axial direction. A drum of the drum brake 104 is fixed to the differential case 30, and a brake shoe is arranged on its inner peripheral surface, although not shown. The brake shoe is connected to a brake lever via a well-known cam mechanism and brake wire. The hub damper 9 and the drum of the drum brake 104 are each rotatably attached to a support frame 10, which allows the differential case 30 to rotate relative to the support frame 10. In addition, a chain 6 extending from the engine is wound around the sprocket 52.

[0031] As in the first embodiment, an axle tube 8 with bearings on both ends is attached to the support frame 10. That is, the axle tube 8 is connected to each support plate 101 via a funnel-shaped bracket 7, and the drive shaft 4 extending from the differential case 30 is inserted into each axle tube 8. The connection with the rear wheels is the same as in the first embodiment.

[0032] In the rear wheel unit configured as described above, the sprocket 52 is attached to the differential case 30 via the hub damper 9, so that sudden power transmission by the chain 6 can be buffered. In addition, a drum brake 104 is attached to the other end of the differential case 3, so that braking can also be performed. Since such hub damper 9 and drum brake 104 can be used that are normally provided on motorcycles, when a motorcycle is converted into a three-wheeled vehicle, the ones provided on the motorcycle can be attached to the differential case 3 as they are and used. Therefore, for example, when it is desired to return a three-wheeled vehicle to a motorcycle, the hub damper 9 and drum brake 104 can be removed from the differential case 3 and used as they are on the motorcycle.

[0033] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-mentioned embodiments, a case has been described in which a rear wheel unit is attached to the rear of a motorcycle when modifying a motorcycle to create a three-wheeled motorcycle, but the above-mentioned rear wheel unit can also be provided when independently designing a three-wheeled motorcycle. [Explanation of symbols]

[0034] 2, 10 Trike support frame (support) 3, 30 Differential case 31 First case member 32 Second case member 33 Pinion shaft 34 Pinion gear 35 Side Gear 4 Drive shaft 5 Sprockets 6 Chain 8 Axle Tube 9 Hub damper 104 Drum brake

Claims

1. A rear wheel unit to be attached to a three-wheeled motor vehicle, A support; A differential case rotatably supported by the support body; A chain is attached to the differential case and is wound around the differential case to transmit power from the drive source. A sprocket having a A differential mechanism housed in the differential case; A pair of drive shafts having the same length extending in opposite directions from the differential case and distributing the rotation of the differential case by the differential mechanism; A pair of rear wheels connected to each of the drive shafts; a pair of axle tubes fixed to the support, each of which houses each of the drive shafts, and each having the same length; A rear wheel unit equipped with

2. The differential case includes first and second cup-shaped case members that house the differential mechanism, The differential case is formed by fitting an opening edge portion of the second case member into an inner circumferential surface of an opening edge portion of the first case member, The rear wheel unit according to claim 1 , wherein the sprocket is attached to an opening edge portion of the first case member.

3. The differential mechanism includes: A pinion shaft rotatably connected to the differential case; a pair of pinion gears attached to both ends of the pinion shaft; a pair of side gears respectively meshing with the pinion gears and connected to the drive shafts; The rear wheel unit according to claim 1 or 2, further comprising:

4. The differential case includes first and second cup-shaped case members that house the differential mechanism, a through hole through which the pinion shaft is rotatably inserted is formed at an opening edge portion of the second case member, The differential case is formed by fitting an opening edge portion of the second case member into an inner circumferential surface of an opening edge portion of the first case member, The rear wheel unit according to claim 3 , wherein both through holes of the second case member are closed by opening edge portions of the first case member.

5. A hub damper attached to one end of the differential case in the axial direction to buffer the power transmitted to the differential case and to which the sprocket is fixed; A drum brake attached to the other end of the differential case in the axial direction; 5. A rear wheel unit according to claim 1, 3 or 4, further comprising:

6. A three-wheeled motor vehicle comprising a rear wheel unit according to any one of claims 1 to 5.

7. A method for converting a motorcycle into a three-wheeled vehicle, comprising the steps of: A preparation step of preparing a rear wheel unit according to any one of claims 1 to 4; a removing step of removing a rear wheel from the motorcycle; a mounting step of mounting the rear wheel unit to a rear end portion of the motorcycle; Equipped with In the mounting step, a chain extending from a drive source of the motorcycle is wound around a sprocket of the rear wheel unit.

8. The method further includes a step of removing a hub damper and a drum brake provided on the motorcycle prior to mounting the rear wheel unit, 8. The method for converting a motorcycle into a three-wheeled motorcycle according to claim 7, wherein, in the preparation step, the sprocket is attached to the hub damper, the hub damper is attached to one end in the axial direction of the differential case, and the drum brake is attached to the other end in the axial direction of the differential case.

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