JPS6029384A - Suspension system for unit swing type engine in motorcycle - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motorcycle equipped with a unit swing type engine, and particularly to a suspension system for the engine unit.

This type of unit swing type engine has an integrated structure with an engine and a transmission case housing an automatic transmission, and a rear wheel driven by the automatic transmission is provided at the rear of the transmission case to form a unit. The front end of this unit is swingably supported by the vehicle body, and the rear part of the transmission case is suspended by a shock absorber installed between the unit and the vehicle body. In such an engine, when a shock is applied to the rear wheels, the entire unit swings around the front end pivot, so the front end of the unit and the vehicle body are linked to absorb and alleviate the impact applied to the front end pivot. It is said that the vehicle body is connected via a member and a rubber vibration isolator is interposed between the vehicle body and the link member.

In this case, it is better to set the spring constant of the vibration isolator to a low value in terms of vibration isolating performance, but since the initial load due to the weight of the unit is applied to this vibration isolator through the link member, it may shorten the life of the vibration isolator. Considering this, the splash constant has to be set relatively high, which results in problems such as sacrificing vibration isolation performance and worsening ride comfort. Moreover, since the link member bears the weight of the unit, it is necessary to increase the rigidity of the link member, which results in an increase in size and weight of the link member.

The present invention was made based on these circumstances, and
The purpose of the present invention is to provide a suspension system for a unit swing type engine in a motorcycle, which can improve vibration damping performance without reducing the life of a vibration damping material, and can also reduce the size and weight of a link member.

That is, in order to achieve the above object, the present invention provides a connection portion between the transmission case and the shock absorber located behind the axle of the rear wheel, and a front end portion of the unit that rotates upward about the axle. The feature is that the load based on the unit's own weight is offset or reduced by applying a force that causes the unit to move.

An embodiment of the present invention will be described below based on the drawings in which the present invention is applied to a scooter type motorcycle.

1 in the figure is a frame as a vehicle body, and this frame 1
is bent significantly downward between the front fork 3 that pivots the front wheel 2 and the seat 4, and a footrest plate 6 is provided at the bottom 5.
is installed.

And the front of the footrest 6 is! It is covered with a leg shield 7 that acts as a windbreak to the 1f41 city, and the seat 4
The lower part of is fallen by cover 8.

The rear end portion of the bottom portion 5 of the frame 1 is bifurcated and raised upward, and engine brackets 10, 10 attached to the lower portions of these raised portions 9, 9 are connected to the engine. The front end of the unit 11 is swingably connected. The engine unit J1 is composed of an engine 12 and a transmission case 14 extending rearward from one side end of a crankcase 13 of the engine 12 as an integrated rigid body.The transmission case 14 also serves as a swing arm, and Inside the transmission case 14, a power transmission means such as a belt type continuously variable transmission is housed.

An axle 16 for a rear wheel 15 is supported at the rear end of the transmission case 14, and the rear wheel 15 is rotationally driven by the power transmission means. A structure for connecting such an engine unit 1 to the frame 1 is shown in FIGS. 2 and 3. That is, the cylindrical bodies 1B, 1B are interposed between the cross member 12, which connects the rising parts 9, 9 of the frame J, and the engine brackets 10, 10, and are tightened by the poles 19, 19. It is fixed, and this cylindrical body 18.18 and bolt 19.19
A vibration isolating material 20.20 is interposed between the two. The vibration isolating material 20° 20 of this embodiment has metal sleeves 22 and 23 baked and fixed to the inner and outer circumferential surfaces of a hollow cylindrical rubber damper 21, and the inner elongated metal sleeve 22 is attached to the outer circumferential surface of a bolt 19. , the rounded outer metal sleeve 23 is connected to the cylindrical body 111.18.
are fixed to the inner circumferential surface of each. Cylindrical body 18.18
A plate-shaped link member 24.24 is connected to the rear surface, and between the rear end portions of these link members 24.24,
Left and right support protrusions 25, 25 are interposed to protrude from the front end of the engine unit 11. The link member 24.24 and the support protrusion s25.25 are connected to the support beam portion 25.24.
Tightening is fixed by a bolt 26 installed between the holes 25 and 25. A portion of the support protrusion 25125 through which the bolt 26 is inserted is provided with another vibration isolator 27.27 having the same structure as the vibration isolator 20.20 described above.

The vibration isolating material 27.27 has an outer metal sleeve 29 on the outer periphery of the rubber damper 28 that is fitted and fixed to the inner surface of the support protrusions 25, 25, and an inner metal sleeve 30 that is attached to the outer circumferential surface of the bolt 26 through a bearing 31. The link member 24 and the engine unit 1 are rotatably connected to each other using the bolt 26 as a fulcrum.

The connection point of the link member 24.24 to the frame 1 side and the connection point to the engine unit 11 side are separated by 14 cm in the longitudinal direction of the vehicle body, and therefore the link member 24.24 extends approximately horizontally. .

) Hl link member 24, 247. ! The J's are connected by a cross paddle 33.

Further, the rear end portion of the transmission case 14 is suspended by one f-motor 34 installed between the upper end portion of one of the raised earth portions 9. The vL percussion device 34 is installed between the rising portion 9 and the rear end of the transmission case 14 in a forward-leaning posture, and the connecting portion 35 of the vL percussion device 34 to the transmission case 14 is shown in FIG. As shown above, the axle 16 of the after-run 15
It is positioned further back by road distance E than the road distance E.

According to such a configuration, when 4 (fi) is applied to the rear wheel 15 while driving, the engine unit 11 moves to the link member 24.2.
It moves up and down with the fulcrum of the joint with 4, (ilII-
is transmitted to the buffer 34, where it is absorbed and relaxed.

By the way, the above-mentioned false bottleneck is not enough if the large key engine unit 11 swings, and the load accompanying this movement is transmitted through the engine unit 11 and the link member 24.24 and the link member 24.24. .24 and the frame 1.

When a load is applied to each connecting portion in this way, the vibration isolating material 20.20 and the 27°27 rubber damper 21.28 interposed in this connecting portion deform and absorb the load. therefore,
# added to the front end, which is the pivot end of the engine unit 11
Since the I-stroke is waved in two stages, the impact is transmitted to the vehicle body, making it smoother and improving the ride comfort.

Therefore, the engine unit 11 and the link member 24.2
An initial 4 dr weight W based on the own weight of the engine unit 1 will be applied to the connection between the engine unit 1 and the shock absorber 34, but in the case of the above configuration, the connection between the engine unit 1 and the buffer 34 will be
5 is shifted rearward from the axle J6 of the rear wheel 15, a moment is generated at the front end of the engine unit 11 due to the repulsive force of the eD-shocker 34, and this front end S is rotated around the axle 16. A reaction force F is applied that simultaneously pushes upward as the center of motion. When the rear wheel 15 is in contact with the ground, the reaction force Fl (!: reaction force F2 from the road surface which the rear wheel 15 receives) acts synergistically on the front end of the engine unit 11, and these reaction forces F and F2
The above-mentioned initial load W is canceled out or reduced by this. In the past, since the initial load W was not applied to the rubber damper 21.28 as it was, the spring constant of the rubber damper 21.28 could be lowered and the rubber damper 21.28 made softer and the fatty acid performance could be improved. , it is possible to further improve one's sense of well-being without reducing one's 28 years of jealousy.

In the same way, the initial load from the engine unit 11 is applied to the link members 24.24 in a state where the initial load is canceled out or compensated for by 4x, so the load burden on the link members 24. Achieved 24 smaller size and lighter weight.”
can.

5. In the above-mentioned actual sushi example, vibration isolating material was also installed at the connection between the link member and the engine unit, or this vibration isolating material was depressed to simply allow the link member and engine unit to rotate freely. It is also good to have a structure that informs the reader.

According to the present invention described in detail above, since the connecting portion between the transmission case and the shock absorber is provided behind the axle of the rear wheel, it is not possible to apply a reaction force that pushes the front end of the engine unit upward. Therefore, the initial load based on the engine unit's own weight is applied to the vibration isolator in a state that is offset or reduced, so the spring constant of the vibration isolator can be lowered accordingly, reducing the life of the vibration isolator. Riding comfort can be improved without any problems. Also, link member load 1
There is an advantage that the burden on the hJ cage is small and the link members are smaller and lighter.

[Brief explanation of the drawing]

The drawings show an example of the invention, and Figure 1 is a side view of the motorcycle, and Figure 2 is a side view showing the suspension state of the engine unit. It is a W1 side view along. DESCRIPTION OF SYMBOLS 1... Vehicle body (7 frames), 11... Engine unit, 12... Engine, 14... Transmission case, 15
... Rear wheel, 16 ... Axle, 20 ... Vibration isolating material, 24
...Link member, 34...Buffer, 35...Connection part.

Claims (1)

[Claims] A transmission case extending rearward is integrally provided at one side end of the engine, and the i
lt and s are provided to form a unit, and the front end of this unit is swingably supported via a link member extending approximately in the longitudinal direction with respect to the vehicle body, and a vibration isolating material is provided at 1111 between this link member and the vehicle body. In a motorcycle equipped with a valve and suspended by a shock absorber installed between the rear part of the transmission case and the vehicle body, the connection portion between the transmission case and the shock absorber,
A suspension system for a unit swing type engine in a motorcycle, characterized in that the suspension system is located behind the axle of the rear wheel.