JPH0517286Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a bushing mechanism used to attach an arm supporting a wheel, such as a trailing arm or a semi-trailing arm, to a body.

BACKGROUND ART FIG. 7 is a schematic diagram showing the outline of a semi-trailing arm suspension, in which a semi-trailing arm (hereinafter referred to as a suspension arm) 1 is bifurcated at one end. These ends are pivotally supported on the subframe via bushes 2a and 2b, so that they are swingably attached to the body 3, and wheels 4 are attached to the other end. In this type of suspension, when a longitudinal force or a lateral force is applied to the wheel 4, the rearward force Fr is applied to the outer bushing 2a.
However, there is also a positive force Ff on the inner bush 2b.
However, if the bushes 2a, 2b are greatly deflected by these forces Fr, Ff, the impact force will be absorbed by the bushes 2a, 2b, improving riding comfort, but the toe angle of the wheel 4 and This causes fluctuations in the campus and reduces maneuverability and stability (handling performance). On the other hand, if the bushes 2a and 2b are made harder to suppress their deflection, the steering stability will be improved, but the riding comfort will be poor.

Therefore, conventionally, the inner bushing 2b, on which a large force acts, is made hard, and the outer bushing 2a is made soft, thereby achieving both ride comfort and maneuverability. For example, in Utility Model Application Publication No. 56-110004, the inner bushing and the outer bushing are eccentrically supported in opposite directions to reduce the amount of displacement in the front-rear direction when bumping and to increase the tendency to toe-in. A configuration has been proposed in which the steering stability is improved by

Problems that the invention aims to solve: However, improving riding comfort and improving handling stability are contradictory demands, and it is not possible to satisfy both with a single fixed structure. In the above-mentioned configuration in which the hardness of the bushings and the outer bushings are different, steering stability is impaired as ride comfort is improved, or conversely, ride comfort is impaired as steering stability is improved. It had the drawback of not being able to provide sufficient comfort and maneuverability. Furthermore, in the configuration proposed in Utility Model Application Publication No. 56-110004 mentioned above, even if a backward force is applied by passing over a small protrusion while traveling straight, the amount of displacement in the longitudinal direction of each bushing is small. Therefore, there is a high risk that the shock force during straight running will not be sufficiently absorbed by the bushings, resulting in poor ride comfort.

This invention was made against the background of the above-mentioned circumstances, and aims to provide a suspension bushing mechanism that can improve both ride comfort and steering stability.

Means for Solving the Problems In order to achieve the above-mentioned purpose, this invention partially varies the hardness of the bush in the circumferential direction and rotates the bush depending on the situation, thereby improving the hardness of the bush. It is constructed to appropriately absorb shock and, on the contrary, suppress the amount of displacement of the bushing. Specifically, a bushing made of an elastic material is interposed at one end of the arm that supports the wheel. In the suspension that is swingably mounted on the body, the bush is formed into a substantially circular cross section with different hardness in part in the circumferential direction, and the bush is rotatably supported on the body;
Further, a pressure generating device that pressurizes fluid to generate fluid pressure when the arm rotates relative to the body is provided between a position of the arm that is off the center of rotation and the body, and The present invention is characterized in that a rotary drive device is provided which rotates the bush by an angle different from the rotation angle of the arm by being operated by fluid pressure from the generator. In addition, in this invention, as a means for varying the hardness of a portion of the bush, it is possible to adopt means such as partially changing the material of the bush or inserting a slit in the bush.

Function: In the bush mechanism of this invention, the hardness of the bush differs in the circumferential direction, so the amount of displacement of the bush differs depending on its relative orientation to the suspension arm. In other words, for example, if the direction of the bushings is initially set so that the soft part is located on the extension of the suspension arm, the bushings will flex greatly and absorb the shock when the vehicle drives over a small protrusion while driving, resulting in a comfortable ride. Become. On the other hand,
In the event of a bump or rebound as a result of turning, the suspension arm rotates relative to the body, causing the pressure generator to generate a predetermined fluid pressure, and the rotary drive device operates due to the fluid pressure. The bush is rotated at an angle different from the rotation angle of the suspension arm. Here, "different angle" includes rotation in the opposite direction, so if the suspension arm rotates, the hard part of the bushing will be located on the extension of the suspension arm, and as a result, the bushing will Since the deflection of the wheel is reduced, there are fewer fluctuations in wheel alignment such as toe angle and camber, improving maneuverability.

Embodiments The present invention will be described below with reference to embodiments and drawings.

FIG. 1 is a schematic plan view showing an embodiment of this invention. With the bush 10 interposed,
a mechanism that rotatably supports the bush 10;
The basic configuration is that a mechanism for rotating the bush 10 by the rotation of the suspension arm 1 is provided. That is, as shown in FIGS. 2 and 3, the bush 10 is made of an elastic material such as rubber and has a circular cross section, and has two parts having a phase difference of 180°.
Arc-shaped slits 11 are formed at the locations,
Therefore, the hardness against the load in the radial direction is soft in the slit portion and hard in other portions. An inner cylinder 12 is fitted into the center of the bush 10, and a bearing 13 is attached to the outer periphery. Therefore, it is attached to the body 3. That is, the bracket 14 has a housing 1 of a rotary actuator 16 which is a rotary drive device operated by fluid pressure.
7 is fixed adjacent to the bush 10,
The inner cylinder 12 protrudes in one direction in the axial direction of the bush 10, and its protruding portion is connected to the housing 17.
The other end of the inner cylinder 12 is connected to a bracket 14.
is supported via a bearing 15. In addition, in order to fix it in the axial direction, the inner cylinder 12
A bolt 18 is inserted through the bolt 18, and a nut 19 is screwed into the tip of the bolt 18.

As shown in FIG. 4, the rotary actuator 16 has the inner cylinder 12 as a rotor,
Two blades 20a and 20b are integrally provided on the inner cylinder 12, and two partition walls 21 are provided on the inner surface of the housing 17, the tip edges of which almost contact the inner cylinder 12.
a and 21b are provided. Therefore, the inside of the housing 17 has four pressure chambers 22a, 22b,
Of these pressure chambers, two pressure chambers 22a and 22c and 22b and 2 are symmetrical about the central axis of the housing 17.
2d are the flow paths 23a and 2 formed in the inner cylinder 12.
3b.

On the other hand, a pressure generating device that generates fluid pressure for operating the rotary actuator 16 is provided between the suspension arm 1 and the body 3.
That is, a cylinder-type actuator 24 is disposed between the upper surface of the middle part of the suspension arm 1 and the body 3, and the arm 1 swings to engage the body 3.
By approaching and separating from the piston, the piston moves up and down, thereby generating fluid pressure. The upper chamber 25a of the actuator 24 and the pressure chamber 22 in the rotary actuator 16
b is connected to the lower chamber 25b of the actuator 24 by a pipe 26a, and the lower chamber 25b of the actuator 24 is connected to the pressure chamber 22b.
The pressure chamber 22a adjacent to the pressure chamber 22a is connected to the pressure chamber 22a by a pipe 26b, and the interior thereof is filled with a pressure fluid such as oil.

The suspension arm 1 is integrally joined to the outer surface of the outer cylinder 13a of the bearing 13 on the outer peripheral side of the bush 10.

Next, the operation of the bushing mechanism constructed as described above will be explained.

When the vehicle is stopped or traveling straight on a flat road, the bush 10 is oriented so that its slit 11 is located on the extension of the suspension arm 1, as shown in FIGS. 2 and 3. The spring constant is small and soft against the load applied from the suspension arm 1 in the longitudinal direction. Therefore, when a load is applied to the bushing 10 in the longitudinal direction due to riding over a small protrusion or the like while the vehicle is traveling straight, the bushing 10 flexes greatly and absorbs the impact, resulting in good riding comfort.

On the other hand, when the vehicle bumps during turning, the suspension arm 1 rotates in the direction of the arrow in FIG. 4 from the state schematically shown by the solid line in FIG. Accordingly, the tube of the actuator 24 rises together with the suspension arm 1, causing the piston to fall relatively.
Fluid pressure is generated in the lower chamber 25b, and the pressure fluid is sent to the pressure chamber 22a of the rotary actuator 16 via the pipe 26b. Since this pressure chamber 22a communicates with a pressure chamber 22c located diagonally through a flow path 23a, the pressure fluid flows through these pressure chambers 22.
a, 22c. On the other hand, the other pressure chambers 22b, 22d communicate with each other via the flow path 23b and are connected to the upper chamber 25a of the actuator 24 via the pipe 26a, so that the interior of these pressure chambers 22b, 22d is The pressure decreases so that the inner cylinder 12 forming the rotor
Rotate clockwise as shown. At the same time, the inner cylinder 12
The bushing 10, which is integral with the rotor, rotates by the same angle clockwise in FIG. This direction of rotation is opposite to the direction of rotation of the suspension arm 1 due to the bump, so the slit 11 of the bushing 10 moves to a position that is out of phase by, for example, 90 degrees from the extended position of the suspension arm 1.
In other words, the hard part of the bush 10 with a large spring constant is located at the extended position of the suspension arm 1.

This situation also applies to the bushing of the suspension arm 1 that supports the wheels on the rebound side during turning, and on the rebound side, the rotating direction of the suspension arm 1 and the rotating direction of the bushing are opposite to the above case. However, in the end, the hard part of the bushing 10 is located on the extension of the suspension arm 1.

Therefore, even if a load is applied from the suspension arm 1 to the bush 10 in this state, the amount of displacement of the bush 10 is reduced, so changes in the toe angle and camber of the wheels 4 are small, and as a result, maneuverability is improved.

5 and 6 show other embodiments of this invention, in which the bushing mechanism shown here uses a linear actuator 27 instead of a rotary actuator.
The bush 10 is rotated by the rotation of the bush 10. That is, the bush 10 is connected to the bolt 29 via the bearing 28 fitted into the bush 10.
The bolt 2 is rotatably supported on the
9 is attached to the body 3 by attaching it to a bracket 14 fixed to the body 3. A bearing 13 is also attached to the outer periphery of the bush 10. The structure of the bush 10 is the same as that of the inner and outer pivot parts of the bifurcated suspension arm 1, and each bifurcated end of the suspension arm 1 is connected to the outer peripheral side of the bush 10. The bearing 13 is connected to the outer cylinder 13a of the bearing 13.
The inner cylinders 13b of the bearings 13 in the inner and outer bushes 10 are connected to each other by a connecting member 30, so that they rotate as one.

A direct-acting actuator 27 operated by fluid pressure is mounted almost horizontally on the upper surface of the suspension arm 1, and its piston rod and the connecting member 30 are connected via a link 31 and ball joints 32, 33. ing. The upper chamber 25a of the actuator 24 is connected to the rear chamber 34a of the direct-acting actuator 27 through a pipe 26a, and the lower chamber 25b is connected to the front chamber 34b through a pipe 26b.

Therefore, in the bushing mechanism configured as described above, when traveling straight on a flat road, the bushing 10 is in the state shown in FIG. For the longitudinal load applied from 1,
The spring constant is small and it is in a soft state.
Therefore, when a load is applied to the bushing 10 in the longitudinal direction due to, for example, riding over a small protrusion while traveling straight, the bushing 10 flexes greatly and absorbs the impact, resulting in a good ride.

On the other hand, when a bump occurs when turning, etc., fluid pressure is generated in the actuator 24 as in the above-described embodiment, and this pressure causes the piston of the direct-acting actuator 27 to move to the right in FIG. 6. As a result, The bush 10 is rotated clockwise in the figure. This is opposite to the rotation direction of the suspension arm 1 about the bolt 29, and therefore the slit 11 of the bushing 10 moves to a position that is out of phase by, for example, 90° from the extended position of the suspension arm 1. In other words, the suspension arm The hard part of the bush 10 having a large spring constant is located at the extended position 1.

This situation also applies to the bushing of the suspension arm 1 that supports the wheels on the rebound side when turning. Since the suspension arm 1 and the bushing rotate in opposite directions, the bushing 10 is placed on the extension of the suspension arm 1. The hard part will be located.

Therefore, in the embodiments shown in FIGS. 5 and 6, even when the load is applied from the suspension arm 1 to the bush 10 during bumps and rebounds associated with turning, the amount of displacement of the bush 10 is reduced.
Changes in the toe angle and camber of the wheels 4 are small, and as a result, maneuverability is improved.

In the above embodiment, the hardness of the bush 10 was partially varied by inserting the slits 11, but this invention is not limited to the above embodiment, and the material of the elastic material constituting the bush may be varied. It is also possible to make the hardness partially different by making the hardness different partially.

Effects of the invention As explained above, according to the suspension bushing mechanism of this invention, the hardness of the bushings differs between when traveling straight and when bumps and rebounds occur due to turning, so it absorbs shock when traveling straight. At the same time, it is possible to prevent changes in wheel alignment by suppressing the amount of displacement of the bushings during turning, thereby improving both ride comfort and maneuverability. In addition, since this invention substantially changes the hardness of the bushings as the vehicle height changes due to the rotation of the suspension arm, if it is adopted in a vehicle with a vehicle height adjustment mechanism, the bushings will change as the vehicle height is adjusted. For example, when driving at high speeds, the vehicle height can be lowered and the spring constant of the bushings can be increased to improve stability at high speeds. Furthermore, for the same reason, when the nose dives during sudden braking, the spring constant of the bushing becomes larger and the influence of external disturbances is reduced, and stability can also be improved in this respect. According to this invention, since only one type of bushing is required, it is possible to obtain effects such as easier parts management and manufacturing work. Furthermore, since this invention is configured to operate using fluid pressure generated as a result of relative rotation between the suspension arm and the body, there is no need to use a link mechanism with a large number of parts. The overall configuration can be made compact and the degree of freedom in design can be increased.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing an embodiment of this invention, Fig. 2 is a view taken along the - line in Fig. 1, Fig. 3 is a view taken along the - line in Fig. 2, and Fig. 4 is a schematic plan view showing an embodiment of the invention. Fig. 2 is a view taken along the - line, Fig. 5 is a schematic plan view showing another embodiment of this invention, Fig. 6 is a view taken along the - line shown in Fig. 5, and Fig. 7 is a semi-trailing FIG. 2 is a schematic plan view showing the general configuration of an arm. 1... Semi-trailing arm, 3... Body, 4... Wheel, 10... Bush, 11... Slit, 12... Inner cylinder, 13, 15, 28... Bearing, 16... Rotating actuator, 24 …
...actuator, 27...direct-acting actuator.

Claims (1)

[Claims for Utility Model Registration] In a suspension in which a bushing made of an elastic material is interposed at one end of an arm supporting a wheel and swingably attached to a body, the bushing has hardness in a part of the circumferential direction. The bush is rotatably supported on the body, and the arm rotates relative to the body to pressurize the fluid and generate fluid pressure. A generator is provided between the arm and the body at a position away from the center of rotation, and is operated by fluid pressure from the pressure generator to move the bush at a rotation angle different from that of the arm. A variable suspension bushing mechanism characterized by being provided with a rotational drive device for rotating the angle.