JPS636399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle with two rear wheels, such as a shaft drive type motor tricycle, and particularly relates to a bearing structure around the rear wheel axis.

[Prior art]

In motor tricycles that travel on sandy or rough ground, etc.
Conventionally, as seen in "Utility Model Application Publication No. 56-152790", a driving bevel gear is provided on the transmission shaft through which engine power is transmitted, and a driven bevel gear is provided on the rear wheel shaft that supports the left and right rear wheels. By providing these bevel gears and meshing them with each other in the gear case,
It is known that the left and right rear wheels are driven by shafts.

[Problem that the invention seeks to solve]

By the way, since this type of tricycle travels on extremely uneven terrain, the impact applied to the rear axle is also quite large. Therefore, if the span of the bearing that supports the rear wheel axle is short, a severe bending moment acts on the rear wheel axle, causing problems such as an increase in the load on the bearing that supports the rear wheel axle.

Moreover, since the driven bevel gear is spline engaged with the rear wheel axle, when a large impact is applied to the rear wheel axle as described above, a considerable load is also applied to the spline engagement portion of the driven bevel gear. Become. Therefore, the spline engagement portion between the driven bevel gear and the rear wheel axle may be worn out or deformed, and power transmission to the rear wheel axle may be hindered.

Therefore, the present invention can reduce the bending moment applied to the rear wheel axle and reduce the burden on the bearings, and also reduce the power from the driven bevel gear to the rear wheel axle without increasing the size of the gear case. The purpose of the present invention is to provide a shaft drive vehicle equipped with two rear wheels capable of ensuring reliable transmission.

[Means for solving problems]

Therefore, in the present invention, a pair of left and right rear arms is provided, and at the rear end of one of the rear arms,
A gear case housing a drive bevel gear through which engine power is transmitted via a transmission shaft is provided, and a bearing support member is provided at the rear end of the other rear arm.
A rear wheel shaft is arranged passing through the gear case and the bearing support member, and the left and right rear wheels are attached to both ends of the rear wheel shaft. The boss portion of the driven bevel gear meshes with the teeth of the driven bevel gear, and the boss portion of the driven bevel gear meshes with the teeth of the driven bevel gear. The rear wheel axle is supported by the gear case via bearings on both sides of the boss part, and the rear wheel axle is supported by the outer end of the gear case located axially outside of the boss part and the bearing support member. It is characterized by being equipped with a bearing.

[Effect]

According to this configuration, since the bearing that supports the rear wheel axle inside the gear case is located at the outer end of the gear case, the span between the bearing and the bearing housed in the bearing support member becomes longer, and the rear wheel axle is correspondingly longer. will be supported at two points near the left and right rear wheels. Therefore, the support point of the rear wheel axle and the rear wheel, which is the point of application of external force, are brought closer together, so that the bending moment acting on the rear wheel axle becomes smaller and the load on the bearing becomes lighter.

In addition, the driven bevel gear that transmits engine power to the rear wheel shaft is supported by the gear case via bearings at two locations on both sides of its teeth, so when viewed from the gear case side, the driven bevel gear appears to be supported at both ends. Become. Therefore, even if a large impact is applied to the rear wheel axle, the driven bevel gear does not tilt on the rear wheel axle, and can be reliably supported within the gear case. At the same time, the bearing that supports the rear wheel axle inside the gear case is located axially outward of the rear wheel axle than the boss of the driven bevel gear. It can be extended, and a sufficient length of the spline engagement portion between the rear wheel shaft and the boss portion can be ensured.

Therefore, in addition to ensuring the support of the driven bevel gear, the load applied to the spline engagement portion during driving can be sufficiently resisted, and power can be reliably transmitted to the rear wheel shaft. .

Moreover, since the bearing inside the gear case is installed at the outer end of the gear case, the boss of the driven bevel gear is extended outward by utilizing the dead space created on the rear wheel shaft. .
Therefore, there is no need to make the gear case larger by the size of the boss portion, and the area around the gear case can be made more compact even though the boss portion is extended to lengthen the spline engagement length with the rear wheel shaft.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

1 in the figure is the vehicle body, which has a steering head pipe 3 at the front end of a main pipe 2, and
A pair of left and right down tubes 4, 4 extend from the steering head pipe 3, and a pair of left and right seat pillar tubes 5, 5 extend from the middle of the main pipe 2. The down tubes 4, 4 and the seat pillar tubes 5, 5 are joined to each other at their lower rear ends.

A front fork 6 that is steered by a bar handle 8 is attached to the steering head pipe 3.
is supported. A front wheel 7 is pivotally supported at the lower end of the front fork 6, and the front wheel 7 is equipped with ultra-low pressure wide balloon tires 9.

From the upper end of the seat pillar tubes 5, 5,
Seat rails 10, 10 extend rearward, and the seat rails 10, 10 are supported by backstays 11, 11 extending from the joint portions of down tubes 4, 4 and seat pillar tubes 5, 5. ing. And seat rail 1
A sheet 12 is installed on the seats 0 and 10.

Also, main pipe 2, down tube 4, 4
An engine 13 is mounted in a space surrounded by the seat pillar tubes 5, 5. An exhaust pipe 14 is led out from the front of the engine 13, and this exhaust pipe 14 is connected to a muffler 15 at the rear.
It is connected to the.

A rear arm assembly 17 is swingably supported at the joint portion of the down tubes 4, 4 and the seat pillar tubes 5, 5 via pivot shafts 16, 16. This rear arm assembly 1
7 is provided with a pair of left and right rear arms 18a, 18b extending rearward, and the front ends of these rear arms 18a, 18b are integrally connected by a front cross member 19, as shown in detail in FIG. . One rear arm 18a also serves as a protective case for a transmission shaft 20 that transmits engine power.

That is, the rear arm 18a is connected to the hollow pipe 2.
1 and 22, these hollow pipes 2
A transmission shaft 20 is inserted into the insides of the transmission shafts 1 and 22. The transmission shaft 20 includes a front shaft 23, an intermediate shaft 24, and a rear shaft 2.
5, whose front shaft 23 is interlocked with an output shaft 26 within the engine case 13a. That is, inside the engine case 13a, the bevel gear 27 of the output shaft 26 and the bevel gear 28 attached to the front shaft 23 mesh with each other, and the bevel gear 28 is connected to the front shaft 23 via the buffer mechanism 29. There is.

The buffer mechanism 29 is engaged with the bevel gear 28 via a cam surface 30a, and is connected between a sleeve 30 that is spline-engaged with the front shaft 23 and a sleeve 31 that is rotatably inserted into the front shaft 23. , spring 3
When excessive back torque is applied to the output shaft 26 from the front shaft 23 side, the sleeve 30 moves to the other sleeve 31 side against the spring 32, and the bevel gear 28 is It is designed to cut off power transmission.

The front shaft 23 and the intermediate shaft 24 are connected to the pivot shaft 16,
16 via a universal joint 33, so that power is transmitted even when the rear arm 18a swings.

Note that a rubber boot 34 is bridged between the front end of the rear arm 18a and the engine case 13a.

Also, the rear shaft 25 has a bearing 38 in the gear case 36.
is supported through. This gear case 36
is attached to one rear arm 18a via bolt 37.
It is removably connected to the rear end of the
The inner surface on the other rear arm 16b side is open, and a ring-shaped cover 46 is attached to the inner surface of the gear case 36 via bolts 47. An internal gear 39 is connected to the front end of the rear shaft 25, and this internal gear 39 meshes with an external gear 40 formed at the rear end of the intermediate shaft 24. Therefore, the rotation of the intermediate shaft 24 is transmitted to the internal gear 39 via the external gear 40, and from this internal gear 39 to the rear shaft 25.

A drive bevel gear 41 is formed at the rear end of the rear shaft 25, and this drive bevel gear 41 is connected to the gear case 36.
It meshes with a driven bevel gear 43 housed inside. The driven bevel gear 43 has a boss portion 43 that extends toward the inner side of the gear case 36 from the tooth portion 43a on its outer periphery.
b, and this boss portion 43b is supported by a cover 46 of the gear case 36 via a bearing 42. Further, a cylindrical sleeve 44 having a straight spline 44a formed on the inner peripheral surface is welded to the inside of the boss portion 43b.
4 is integrated with the boss portion 43b by welding,
It is substantially a part of this boss portion 43b.
As is clear from FIG. 3, this sleeve 44 extends further toward the outer surface of the gear case 36 than the teeth 43a of the driven bevel gear 43, and this extended portion 44b extends through the roller bearing 45. It is pivotally supported by a gear case 36.

Therefore, the driven bevel gear 43 has its teeth 43a.
It is supported by a gear case 36 on both sides of the gear case 36, and when viewed from the gear case 36 side, it is supported at both ends.

A bearing case 50 serving as a bearing support member is welded to the rear end of the other rear arm 18b, and one end of a hollow hub 51 that also serves as a rear cross member is welded to the inner end of this bearing case 50. . The other end of the hollow hub 51 is connected to the gear case 3.
6. That is, the cover 46 of the gear case 36 is detachably connected to the flange 51a of the hollow hub 51 via the bolt 52.

Therefore, the left and right rear arms 18a, 18
b, front cross member 19, gear case 36
The hollow hub 51 has a rectangular frame shape and constitutes the rear arm assembly 17.

A bracket 53 is welded to the hollow hub 51, and a hydraulic shock absorber 54 is spanned between the bracket 53 and the rear end of the main pipe 2.

On the other hand, a hollow pipe-shaped rear wheel shaft 55 is horizontally suspended between the rear end portions of the rear arms 18a and 18b, passing through the bearing case 50, the hollow hub 51, and the gear case 36. Left and right rear wheels 56, 56 are attached to both ends of the rear wheel shaft 55 so as to rotate together with the rear wheel shaft 55.
56 is equipped with balloon tires 9, 9 similar to the front wheels 7.

A straight spline 59 is carved on the outer peripheral surface of the portion of the rear wheel shaft 55 that passes through the gear case 36, and this straight spline 59 is connected to the straight spline 44a on the inner peripheral surface of the sleeve 44.
are in mesh with each other, so that the rear wheel shaft 55 and the driven bevel gear 43 rotate together. One end of such a rear wheel shaft 55 is pivotally supported by the gear case 36 via a bearing 57, and the other end is pivotally supported by the bearing case 50 via another bearing 58. A bearing 57 that pivotally supports one end of
is the extension 4 of the sleeve 44 as shown in FIG.
4b is provided at the outer end of the gear case 36 located axially outer of the rear wheel shaft 55 than the gear case 4b.

In FIG. 3, reference numeral 60 indicates a brake disk attached to the rear wheel shaft 55, and reference numeral 61 indicates an oil seal.

Further, the openings at both ends of the rear wheel shaft 55 are hermetically closed by rubber caps (not shown) or the like.

A tricycle with such a configuration has an engine 13.
The power is transmitted from the output shaft 26 via the front shaft 23 and the intermediate shaft 24 to the rear shaft 25 in the gear case 36, and from the drive bevel gear 41 of the rear shaft 25 to the sleeve 44 via the driven bevel gear 43. Reportedly. Thus, the sleeve 44 drives the rear wheel shaft 55 with which it is splined.

When the rear wheels 56, 56 receive an impact from uneven ground while driving on rough terrain, the rear wheels 56, 56
Although the balloon tires 9, 9 cushion the impact to some extent, the impact that cannot be completely cushioned by the balloon tires 9, 9 is transmitted from the rear wheel shaft 55 to the rear arm assembly 17 via the bearings 57, 58.
The rear arm assembly 17 has a pivot shaft 16,
16, the shock transmitted to the rear arm assembly 17 is transmitted to the hollow hub 5.
The hydraulic shock absorber 54 installed between the main pipe 1 and the main pipe 2 absorbs and relaxes the water.

By the way, according to the above configuration, the gear case 36
The bearing 57 that supports the rear wheel shaft 55 inside is provided at the outer end of the gear case 36, which is located further axially outside the rear wheel shaft 55 than the extension 44b of the sleeve 44, so that the bearing 57 and the bearing case 50 and the bearing 58 becomes longer, and the rear wheel shaft 55 is supported at two points close to the rear wheels 56, 56.

As a result, the bearing 5 serves as a support point for the rear wheel shaft 55.
7, 58 and the rear wheel 5 as the point of application of external force.
6 and 56 are closer together, the bending moment acting on the rear wheel shaft 55 becomes smaller, and the rear wheel shaft 55 can be made smaller in diameter or hollow.
Weight reduction can be achieved.

Moreover, since the bending moment applied to the rear wheel shaft 55 is reduced, the load on the bearings 57, 58 is also reduced, and the life of these bearings 57, 58 is extended.

Furthermore, the driven bevel gear 43 that transmits engine power to the rear wheel shaft 55 is supported by the gear case 36 via bearings 42 and 57 at two locations on both sides of the toothed portion 43a. It will be supported at both ends. Therefore, even if a large impact is applied to the rear wheel axle 55 while driving, the driven bevel gear 43 will not tilt on the rear wheel axle 55.
It can be reliably supported within the gear case 36.

At the same time, the rear wheel shaft 55 is
The bearing 57 supporting the sleeve 4
4, the sleeve 44 can be extended along the rear wheel shaft 55 to the position of the bearing 57, and the spline engagement between the rear wheel shaft 55 and the sleeve 44 A sufficient length can be ensured.

Therefore, the driven bevel gear 43 can be reliably supported without tilting, and the load applied to the spline engagement portion with the sleeve 44 can be sufficiently resisted when the rear wheel shaft 55 receives an impact while driving. Thus, power can be reliably transmitted from the driven bevel gear 43 to the rear wheel shaft 55.

In addition, since the bearing 57 is located at the outer end of the gear case 36, the extension 44 of the sleeve 44
b is extended outward by utilizing the dead space created on the rear wheel shaft 55 within the gear case 36. Therefore, there is no need to make the gear case 36 larger by the extent of this extension 44b, and the area around the gear case 36 can be made more compact even though the spline engagement length between the rear wheel shaft 55 and the sleeve 44 is lengthened. .

It is also possible to connect the gear case 36 directly to the hollow hub 51 without using the cover 46, but as in the above configuration, the cover 46 is attached to the gear case 36 in advance and the driven bevel gear 43 is connected to the bearing 41.
2, the tooth contact with the drive bevel gear 41 can be adjusted.

Furthermore, by directly welding the driven bevel gear 43 and the sleeve 44, the power transmission structure from the driven bevel gear 43 to the rear wheel shaft 55 can be simplified, and the number of parts and weight can be reduced.

In the above embodiment, the bearing case and the gear case are connected by a hollow hub, but if the rigidity of the rear arm is sufficiently high, the hollow hub may be omitted.

Furthermore, the rear arm assembly is not limited to being pivotably supported on the vehicle body, but may be rigidly fixed in some cases.

〔Effect of the invention〕

According to the present invention described in detail above, the rear wheel axle is supported near both ends near the left and right rear wheels, and the bearing span is lengthened, so that the bending moment applied to the rear wheel axle is reduced, and the load on the bearing is also reduced. It's lightweight.

In addition, the driven bevel gear that transmits engine power to the rear axle is supported at both ends by the gear case, so even if a large impact is applied to the rear axle, the driven bevel gear will not tilt on the rear axle. Support is assured. At the same time, since the bearing that supports the rear wheel axle inside the gear case is located at the outer end of the gear case, the boss of the driven bevel gear is extended to the position of this bearing to lengthen the spline engagement length with the rear wheel axle. You can take it. Therefore, it is possible to sufficiently resist the load applied to the spline engagement portion during driving, and power can be reliably transmitted from the driven bevel gear to the rear wheel shaft.

In addition, the extension of the boss is extended outward by utilizing the dead space created on the rear wheel axle within the gear case, so even though the spline engagement length between the rear wheel axle and the boss has been lengthened, First, it has the advantage that the area around the gear case can be formed compactly.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a side view showing the body structure of a tricycle, FIG. 2 is a plan view thereof, and FIG. 3 is a sectional view showing the rear arm assembly and power transmission system. . 13... Engine, 18a, 18b... Rear arm, 20... Transmission shaft, 36... Gear case, 41... Drive bevel gear, 42, 49... Bearing, 43... Driven bevel gear, 43a... Teeth, 43b... Boss, 44... Sleeve , 50...bearing support member (bearing case), 55
...Rear wheel axle, 56...Rear wheel, 57, 58...Bearing.

Claims (1)

[Scope of Claims] 1. A gear case is provided at the rear end of one of the left and right rear arms, which houses a drive bevel gear to which engine power is transmitted via a transmission shaft, and a gear case housing a drive bevel gear to which engine power is transmitted via a transmission shaft is provided. A bearing support member is provided at the rear end, a rear wheel axle is arranged passing through the gear case and the bearing support member, and the left and right rear wheels are attached to both ends of the rear wheel axle, and the gear case of the rear wheel axle is installed. On the outer circumferential surface of the part,
A shaft drive type vehicle comprising two rear wheels in which a boss portion of a driven bevel gear that meshes with the driving bevel gear is engaged with a spline, and engine power is transmitted to a rear wheel shaft by the bevel gears that mesh within the gear case. , a gear case that pivotally supports the boss portion of the driven bevel gear on both sides of the driven bevel gear via bearings, and is located outside the boss portion in the axial direction of the rear wheel shaft; 1. A shaft drive vehicle equipped with two rear wheels, characterized in that bearings for pivotally supporting a rear wheel shaft are provided at the outer end of the wheel and the bearing support member, respectively.