JPH0141673Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a power unit device for a vehicle.

As a conventional device of this kind, Japanese Patent Laid-Open No. 57-118968 discloses a power unit in which an engine and a transmission case with drive wheel axles are integrally assembled on a swing arm that is suspended on the vehicle body via a shock absorber. It is known that it is attached via cushion material.
In this case, the front and rear axles of the unit are generally attached to the swing arm through cylindrical cushioning materials, which prevents horizontal vibrations during acceleration and deceleration of the vehicle. A certain degree of buffering effect can be obtained against the horizontal component of the impact when riding or overcoming unevenness on the road surface, but in order to obtain a sufficient buffering effect, the cylindrical cushion material should be soft and thick. This has the disadvantage of increasing the degree of freedom of the unit.

The purpose of the present invention is to provide a device that eliminates such inconveniences.The present invention is based on a swing arm that is suspended from the vehicle body via a shock absorber, and the power unit is positioned approximately directly below the axle of the swing arm. The unit is rotatably supported by a shaft, and the unit is supported by the swing arm via a cushion material that is stretchable in the tangential direction of a circle centered on the support shaft. It is characterized in that the main excitation force directions of the engine are made to substantially match.

The present invention will be explained below with reference to the illustrated embodiments.

In the drawings, reference numeral 1 designates a tricycle body comprising a front wheel 2 and a pair of left and right rear wheels 3, 3 which are drive wheels, and the body 1 is separated into a front body 1a and a rear body 1b. 1a and 1b are connected via a rolling joint 1c, and a shock absorber 4 is attached to the rear vehicle body 1b.
A swing arm 5 is provided, and an engine 6 and the rear wheels 3, 3 are mounted on the swing arm 5.
A power unit integrally assembled with a transmission case 8 having an axle 7 was attached via a cushion material 10, and the whole was constructed into a bank type tricycle.

Here, the swing arm 5 includes a pair of substantially parallel left and right arm members 5a, 5 extending rearward of the vehicle body 1.
a, and a pair of front and rear cross members 5b, 5b that connect the two arm members 5a, 5a, and the swing arm 5 is connected to the rear vehicle body 1b by hinge parts 5c, 5c at the front ends of the two arm members 5a, 5a.
The arm members 5a, 5a are pivotally connected to the vehicle body 1b at substantially intermediate portions thereof, and are suspended via shock absorbers 4, 4, respectively. The power unit 9 is composed of an engine 6 at the front thereof, and a transmission case 8 extending rearward from the bottom of the engine 6, and the axle 7 is inserted into the rear end of the transmission case 8.
An air cleaner 11 is disposed in the upper part of the case 8, and a muffler 12 is disposed behind the air cleaner 11.

Although the above is not particularly different from the conventional one, according to the present invention, the unit 9 is rotatably supported on the swing arm 5 by a support shaft 13 located approximately directly below the axle 7, and the unit 9 is is supported by the swing arm 5 via a cushion material 10 that is expandable and contractible in the tangential direction of a circle centered on the support shaft 13, and the main excitation force of the engine 6 of the unit 9 is applied in the expansion and contraction direction of the cushion material 10. The unit 9 has a pair of left and right brackets 14 extending substantially directly below the axle 7, and the unit 9 is arranged so that the directions F substantially coincide with each other. Mounting holes 14a, 14 provided in
Both arm members 5a, 5 of the swing arm 5 at a
a are rotatably supported by support shafts 13 each made of a bolt, and furthermore, on the front lower surface of the unit 9, there is a support shaft 13 that is substantially aligned with the main excitation force direction F of the engine 6 and centered around the support shaft 13. A guide rod 15 extending in the tangential direction of the circle is fixed, and the rod 1 is attached to the cross member 5b of the swing arm 5.
A catch seat 16 perpendicular to the axial direction of the rod 15 is fixedly installed, and the rod 15 is inserted into the catch seat 16.
The cushion material 10 is applied so as to grip the seat 16 from above and below in the axial direction of the rod 15,
The cushion material 10 is made to expand and contract in the tangential direction, and the direction of this expansion and contraction is made to substantially coincide with the main excitation force direction F of the engine 6.

Note that when the cushion material 10 is placed close to the support shaft 13 of the unit 9, the cushion material 10 is relatively small compared to when the cushion material 10 is placed away from the support shaft 13. The cushion material 10 can be made of a hard material.
The mounting space for the cushion material 10 can be reduced, and the durability of the cushion material 10 is effectively improved by making it hard.

Next, its operation will be explained.

When the vehicle is running, the vertical component of the impact that is applied to the power unit 9 via the axle 7 due to uneven road surfaces, etc. is applied to the shock absorbers 4, 4 of the swing arm 5.
This point is the same as in conventional models, but in the case of conventional models, the horizontal component force must be absorbed by the horizontal expansion and contraction of the cushion material caused by the horizontal movement of the power unit. This causes the above-mentioned inconveniences.

On the other hand, according to the present invention, the horizontal component force causes the unit 9 to rotate about the support shaft 13 located approximately directly below the axle 7, and this movement It is received by a cushion material 10 that is stretchable in the tangential direction of a circle centered on 13,
The horizontal force component is thus absorbed by the cushion material 10. Furthermore, horizontal vibrations caused by acceleration and deceleration of the vehicle are also absorbed by the cushion material 10, and the main excitation force direction F of the vibrations of the engine 6 of the unit 9 and the direction of expansion and contraction of the cushion material 10 are substantially the same. is absorbed by the cushion material 10.

In the illustrated embodiment, the support shaft 13 is supported by the swing arm 5 via a rubber bush 17 so as to prevent engine vibrations from being transmitted to the swing arm 5 via the axle 13. Here, the bush 16 does not need to directly absorb shocks caused by unevenness of the road surface, etc.
Since the unit 9 can be made relatively hard, the degree of freedom of the unit 9 is increased and the running stability of the vehicle does not deteriorate.

As described above, according to the present invention, the power unit is rotatably supported by the swing arm, which is suspended from the vehicle body via the shock absorber, on the support shaft located approximately directly below the axle, and the power unit is supported rotatably around the support shaft. It is supported through a cushion material that is expandable and contractable in the tangential direction of a circle, and the direction of the main excitation force of the engine is approximately aligned with the direction of expansion and contraction of the cushion material, so that the vibration of the engine and the running of the vehicle are Not only can the shock of time be reliably absorbed, but the movement of the unit is restricted only to the rotational direction about the support shaft, which is advantageous.

[Brief explanation of drawings]

Fig. 1 is a side view of a tricycle on which the unit device of the present invention is mounted, Fig. 2 is a rear view thereof, Fig. 3 is an exploded perspective view of the main parts, and Fig. 4 is a side view taken along the line - - in Fig. 2. , and FIG. 5 is an enlarged rear view cut along the line . 1... Vehicle body, 3, 3... Rear wheel (drive wheel), 4...
...Buffer, 5...Swing arm, 6...Engine, 7...Wheel, 8...Transmission case, 9...Power unit device, 10...Cushion material, 13...
...Support shaft, F...Direction of the main excitation force of the engine.

Claims (1)

[Scope of utility model registration request] A power unit in which an engine and a transmission case including an axle for the driving wheels are integrally assembled is mounted on a swing arm that is suspended on the vehicle body via a shock absorber via a cushion material. The unit is rotatably supported by a support shaft located substantially directly below the axle, and the unit is supported by the swing arm via a cushion material that is expandable and contractible in the tangential direction of a circle centered on the support shaft. A power unit device for a vehicle, characterized in that the main excitation force direction of the engine of the unit is made to substantially coincide with the direction of expansion and contraction of the cushion material.