JPS6021915B2 - Power unit suspension system for motorcycles, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power unit suspension system for a motorcycle or the like.

The power unit swing mechanism integrates a case housing the engine and engine power transmission means, and pivots the case to the vehicle body so that it can swing freely, forming part of the suspension system.The power unit swing mechanism is used as a drive and suspension system for motorcycles. It has been adopted.

In this type of power unit swing mechanism, the engine side is pivotally connected to the vehicle body, and the excitation force and vibration caused by engine operation are transmitted to the vehicle body, and are transmitted as vibrations to the vehicle body during driving and idling, improving ride comfort. In addition to inhibiting
Road surface reaction force applied to the power unit due to road surface irregularities during driving is transmitted to the vehicle body as a tensile force or the like, impeding ride comfort. In order to improve the above problems, it has been proposed to connect the vehicle body side and the engine, that is, the power unit, with an IJ link, or to interpose an elastic body between them. Power unit against impact,
It is difficult to obtain a wheel that fully satisfies both wheel followability. In particular, the vehicle body and the front part of the power unit are pivotally connected in the longitudinal direction by a linear link, and a rubber bush is interposed in the pivot joint, and the link is mainly tensioned (pressed).
A system in which a force is applied has been proposed, and although this improves the followability of the wheel to some extent, compressive force in the downward direction acts on the rubber bushing due to tension (pressure), and as a result, the spring rate decreases. becomes high, and it is difficult to obtain a sufficient effect of suppressing engine vibration, especially vibration propagation to the car body during idling.In order to suppress vibration propagation, it is necessary to lengthen the link and make the rubber bush softer. This inevitably increases the length of the IJ link, which is disadvantageous in terms of space, and also has disadvantages such as a reduction in the lifespan and durability of the rubber bushing. Therefore, the applicant first decided to
A power unit suspension system was proposed as No. 8382.

This connects the vehicle body and the front lower surface of the power unit through a link that allows for free rotation around the front and rear pivot joints.
All loads such as the weight of the unit and the reaction force of the reaction unit acting on the link from the power unit side are converted into a rotational moment of the link, and the link is equipped with a reaction force against this rotational load by using rubber bushings, etc. An elastic body is interposed, which elastically supports all the loads and reaction forces on the wheel side by swinging due to the load in the rotational direction of the link, increasing the ability to follow the road surface and improving riding comfort. By using the elastic body as a hollow around the support shaft, the spring rate is effectively lowered, and while the length of the link is set small, the transmission of engine vibrations to the vehicle body is suppressed and reduced as much as possible, improving ride comfort. This has many advantages, such as further improving performance, reducing the length of the link, and allowing the engine and vehicle body to be brought closer together.

The present inventors have devised the present invention in order to further enhance the effectiveness of the above-mentioned improved vibration-proof suspension system for a power unit of a motorcycle.

An object of the present invention is to interpose an elastic body such as rubber between the middle part of the IJ link and the front part of the power unit facing it, and the elastic body is divided with the link in between and connected. By using this elastic body, it is possible to suppress the transmission of engine vibrations to the link and the vehicle body, further improving the vibration damping properties. To provide a power unit suspension device for a motorcycle, etc., which elastically supports the movement in the direction and also provides elastic support during rebound, thereby further improving the above-mentioned effects, and which is also easy to structure and manufacture. be.

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a side view of the rear part of the motorcycle, and the front part is omitted because it is already known.

At the rear of the main frame 2 of the motorcycle 1, a curved inverted L-shaped rear frame 3 is curved upward and backward, and a seat 4 is attached thereto, surrounded by a body plate 5 and a rear fender. Surrounded by 6. 7 is a power unit, and the power unit 7 consists of an engine 8 installed at the upper front, a crank case 9 below this, a transmission case 10 extending behind this, etc., and the transmission case ID includes a transmission and a transmission case. The internal mechanisms and other components all make up the power unit.

A rear wheel 11, ie, a driving wheel, is supported on the rear part of the transmission case 10, and is connected to the rear part of the rear catcher frame 3 of the case I0 via a cushion unit 12 whose upper part is in the front. The front part of the power unit 7 described above is connected to the front lower part of the rear frame 3 on the vehicle body side.

The details are as shown in Figs. 2 and 3, and 13 indicates a link. The link 13 is made of a press-formed steel plate material, and has a substantially rectangular shape long in the front and back of the plane, and there are large bumps on both sides of the link. The side plates 13a, 13a are bent and suspended to provide rigidity.

Support protrusions 9 are drilled in the width direction of the crank case 9 on the left and right sides of the lower surface of the crank case 9, which forms the front part of the power unit 7.
a, 9a protruding downward, and insert the inner and outer rings 1 into the mounting holes 9b.
Rubber bushing 1 with inner and outer fleas attached to 4a and 14b
A collar 15 having the same diameter as the inner ring 14a is installed between the rear parts of both side plates 13a and 13a of the link 13, and a bolt forming a rear horizontal axis is attached to the left and right inner rings 14a and 14a and the collar 15 between them. 16 and tighten with a nut 17 from the outside of one of the protrusions. In this way, the front lower surface of the power unit 7 is pivotally attached to the rear part of the link 13 via an elastic body such as a rubber bush. Cylindrical members 18, 18 are fixed to the front parts of the left and right side plates 13a, 13a of the link 13 by welding or the like, and a rubber fitting 19 with inner and outer rings 19a, 19b attached thereto is attached to the inner diameter of the cylinder members 18, and the inner ring 19a , 19a
With a collar 20 interposed between them, bolts 21 forming the front horizontal axis are connected from the outside of one of the U-shaped lower side pieces 3a, 3a of the rear frame 3 to the inner ring of one rubber bush, the collar, the inner ring of the other, It is passed through to the outside of the other side piece so as to be structured, and is vertically attached with a nut 22. In this way, the front part of the link 13 is pivotally connected to the vehicle body side, and the rotation of the support shaft 21 is transmitted to the rubber bush 19 via the inner ring 19a, and the bush 19 is connected to the cylindrical member 1.
8 supports the outer light part. Thus, the front and rear horizontal koji 16,
The vehicle body and the front lower surface of the power unit are connected by a link 13, which is rotatable around a pivot joint 21, and the front part of the power unit 7 is set with a net so as to cover the rear part of the link 13. .

The front rubber bushing 19 is designed so that when a rotational force around the shaft 21 of the link 13, a clockwise rotational force as shown in FIG. , and the rubber bush 19 is preloaded in a direction that opposes the rotational force, that is, in a counterclockwise direction. The link 13 described above is arranged so as to be substantially perpendicular to the direction of the main crank excitation force of the engine 8, which is indicated by the arrow in FIG.

In the above, the loads acting on the power unit 7 are the weight of the power unit 7, the load reaction force of the rear wheel 11, and the buffer reaction force of the rear cushion unit 12, and these act as a downward rotational load around the rear wheel axle. However, this downward rotational load is converted from the rear part of the link 13 into a rotational moment about the front support shaft 21, and the link 13 acts as a rotating link with the support shaft 21 as a fulcrum.

This rotational load is supported by compressive deformation in the circumferential direction of the rubber bush 19, that is, by the rubbing action around the marrow of the bush 19, and the movement of the power unit in the longitudinal direction due to vertical reaction forces from the road surface and road surface irregularities is also supported by the above. It is elastically absorbed, and the transmission to the vehicle body is suppressed and alleviated. Also link 13
The main excitation force of the engine 8 is absorbed by the vertical rocking of the engine 8 because its direction and the link are substantially perpendicular to each other. The propagation of vibrations during idling to the vehicle body side is more effectively prevented by the length of the link 13 and the rubber bush 19 elastically supported in the rotational direction. By the way, an elastic body such as a rubber member is interposed between the intermediate portion of the link 13 and the front lower surface of the power unit 7 above.

That is, as is clear from FIGS. 2 and 3, the rubber member 23 has a cylindrical shape, the thickness of the inner collar of the lower part 23a is reduced to facilitate deformation, and a support plate 24 is provided on the upper surface. Pass the stay 25 vertically fixed to this through the inner flanges 23b, and
The play hole 13 of the recess 13b provided in the middle part of the link 13
It hangs down through c.

At the lower part of the hanging part of the stay 25, there is a threaded part 25a provided at the lower end.
Fasten the support plate 26 with a nut 28 through the
A stay 25 is mounted on the supporting plate 26 spaced apart from the bottom surface of the link 13.
A pump stopper rubber 27 is provided so as to surround the lower circumference of the pump,
Under normal conditions, a clearance exists between the rubber 27 and the lower surface of the recess 13b of the link 13. To attach the rubber member 23 to the power unit side, a recess 9c is provided on the lower surface of the crankcase 9 and is open to the lower surface and the sides, and the inner walls of the front and rear portions 9d and 9d of the recess 9c are opened laterally and inwardly. Grooves 9e, 9e are provided, and the front and rear ends 24a, 24a of the support plate 24 on the rubber member 23 are inserted and engaged from the sides. In the above, the lower surface of the engine 7 constituting the front portion of the power unit 7 is elastically supported on the intermediate portion of the link 13 via the rubber member 23 as well.

This member 23 acts as a compression side, so that the rotational load acting on the front part of the power unit is also supported in a direction that is canceled out, and in combination with the above, provides effective elastic support. In particular, the engine's main force o vibration is as shown by the arrow, and this is absorbed by the elastic sagging action of the rubber member 23 on the link 13, and the transmission of this to the link 13 and the vehicle body is further absorbed in this part. The effect of suppressing and preventing vibrations from being transmitted to the vehicle body can be further enhanced, and most of the vibrations generated during engine idling are absorbed by the rubber member, which has a large capacity, thereby preventing transmission to the vehicle body. I can do it. The effect of suppressing vibration propagation to the vehicle body by the rubber member 23 as described above depends on the spring constant of the section. It can be freely set by changing the ratio of the distance 12 between and the spinal column 16, and since the rubber member 23 is provided on the link 13, the ratio of 1 and 12 can be easily set large. Therefore, although the spring characteristics of the link 13 as a whole are sufficiently low, the support shaft 16 on the power unit side as shown in the figure
It is possible to use rubber with relatively hard spring characteristics by providing the rubber at a position close to the rubber, which is advantageous in terms of durability. This 1,,1
By arbitrarily selecting the ratio of 2, an optimal spring constant for suppressing vibration propagation can be obtained. The extension side of the front part of the power unit 7, that is, the upward movement with respect to the link 13, is relaxed and absorbed by the collision of the lower rubber member 27 with the link 13.

That is, the rubber member 27 functions as a rebound cushion stopper, and the vertical movement of the front part of the power unit is effectively relaxed and absorbed as compressive deformation of the upper and lower rubbers 23 and 27, and the rebound stopper member 27 is affected by the load of the power unit. Because of this, the capacity has been reduced. Although the illustrated embodiment has been described in detail above, the specific shape and structure of the rubber members 23 and 27, and the means for supporting and connecting them are arbitrary.

As detailed above, according to the present invention, all the loads and reaction forces acting on the power unit act on the link as a rotational moment, and the link is elastically supported as a rotating link by rubber bushings, etc., so that it is transmitted from the road surface through the power unit to the vehicle body. It effectively suppresses and blocks the loads and vibrations transmitted to the sides, and also has high road surface followability, significantly improving the riding comfort of motorcycles, and suppressing engine vibrations. In addition, since a rubber member is interposed between the link and the front lower surface of the power unit, engine vibrations are also absorbed and blocked, and engine vibrations, especially during idling, are removed by the rubber member and the link. It is possible to obtain a motorcycle with very little vibration, which is effectively absorbed and isolated by the elastic support of the pivot joint.

In addition, since the above rubber parts were placed above and below with the link in between,
In addition to the above, it also functions as a bump cushion stopper when placed over the power unit, and by selecting the distance between the link and the rubber member, spring characteristics with high vibration suppression effects can be easily obtained, and the structure and installation are also simple. It has many advantages.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a side view of the rear part of the motorcycle, Fig. 2 is an enlarged sectional view of the same main part, Fig. 3 is a partially cutaway plan view of the same, and Fig. 4 is a partial view. FIG. 2 is an explanatory plan view of the broken rear part of the motorcycle. In the drawing, 2 and 3 are the vehicle body, 7 is a power unit, 13 is a link, 16 and 21 are pivot joints, 19 is an elastic body, and 23 and 27
is rubber. Flag 1 map N Striped map Swallow map size ship

Claims (1)

[Claims] 1. The vehicle body and the front lower part of the power unit are connected via a link that is rotatable around the front and rear pivot joints, and the pivot joints have an elastic structure that has a reaction force against the rotational load around the axis. In addition, an upper and lower elastic body is provided between the upper and lower support plates connected by a connecting member in the middle part of the link so as to sandwich the link and cooperate with each other, and the upper support plate is placed on the power unit side. 1. A power unit suspension system for a motorcycle, etc., characterized in that a fixed upper elastic body is interposed between the front lower part of the power unit and the upper surface of a link intermediate part.