JPH0572282B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a strut-type suspension installed in an automobile.

(Prior Art) Conventionally, an automobile suspension has been provided with an extendable shock absorber having a cylinder and a piston rod, and the lower part (cylinder side) of the shock absorber is
is fixed to the wheel support member, and the upper part (piston rod side) is swingably supported by the vehicle body via a mount rubber, and the vertical vibration of the wheel is damped by the expansion and contraction of the shock absorber.This is a so-called strut type suspension. is generally well known.

However, the shock absorber for such a strut-type suspension has its lower end fixed to the wheel support member, and is placed inside the wheel to avoid interference with the wheel, so it cannot be used when the vehicle is in a stationary state. The center axis is located downward and inward in the vehicle width from the line of action of an external force received from the vehicle body as a reaction force of the ground load acting on the wheels. Therefore, a bending load is applied to the piston rod due to a component force perpendicular to the central axis of the external force, causing a convex bending deformation inward in the vehicle width, resulting in a large frictional resistance at the sliding contact area between the piston rod and the cylinder. This caused a problem in that the damping function against the vertical vibration of the wheel was not sufficiently exerted.

Therefore, in order to solve this problem, the piston rod support axis of the mount rubber, which is the attachment member of the shock absorber (piston rod) to the vehicle body, in a free state before the shock absorber is assembled is changed to the piston rod support axis after the shock absorber is assembled. By installing the piston rod downward from the axis and toward the outside of the vehicle width, the restoring force of the mount rubber applies a convex bending load outward to the vehicle width to the piston rod after the shock absorber is assembled, and the bending load and the vehicle body are Since then, a system has been proposed in which the bending load due to external force acting on the piston rod cancels each other out (Utility Model No. 57-
(See Publication No. 96012).

However, in the above proposal, since a constant bending load is merely applied to the piston rod, it is difficult to obtain a sufficient canceling effect between the bending loads. In other words, the bending load due to external force acting on the piston rod from the vehicle body is proportional to the ground load acting on the wheels, and varies depending on the loaded weight, etc. Also, the direction of action of the ground load changes when turning. This is because the direction of action of the external force changes as well, and may fluctuate accordingly. In particular, during sharp turns, the direction of external force acting on the piston rod of the shock absorber on the side opposite to the direction of the turn becomes downward and inward in the vehicle width from the central axis of the shock absorber, causing bending loads caused by the external force. The direction of action may even be reversed from when the vehicle is at rest.

(Object of the Invention) In view of the above points, the object of the present invention is to reduce the amount of bending load caused by an external force acting on the piston rod of a shock absorber even if the bending load changes with the change in the magnitude and acting direction of the ground load. By providing an appropriate means capable of applying a bending load to the piston rod according to the direction of action so that the bending loads reliably cancel each other out, bending deformation of the piston rod is prevented and sliding between the piston rod and the cylinder is improved. The objective is to effectively reduce frictional resistance at contact parts.

(Structure of the Invention) In order to achieve the above object, the structure of the present invention is provided inside the vehicle body of each wheel corresponding to the left and right wheels, the lower part of each wheel is fixed to the wheel support member, and the upper part is fixed to the vehicle body. A pair of left and right shock absorbers, each having a pair of left and right shock absorbers swingably supported by the vehicle body, and a first pressure chamber and a second pressure chamber opposing each other, each connected to a piston rod of each of the shock absorbers and supported by the vehicle body. a fluid actuator device, a first pipe that connects a first pressure chamber of each of the fluid actuator devices to a pressure chamber of the shock absorber on the opposite side of the fluid actuator, and a second pressure chamber of each of the fluid actuator devices; and a second pipe communicating with the pressure chamber of the shock absorber on the same side as the fluid actuator. Each of the fluid actuator devices protrudes outward in the width direction of the vehicle due to the pressure generated in the pressure chamber of the shock absorber on the opposite side of the fluid actuator device, with respect to the piston rod of the shock absorber connected to the fluid actuator device. It is configured to apply a bending load that is convex inward in the vehicle width by the pressure generated in the pressure chamber of the shock absorber on the same side as the fluid actuator device.

As a result, when the ground load acts vertically upward on the wheels when traveling straight, equal internal pressure is generated in the pressure chambers of the pair of left and right shock absorbers, each corresponding to the size of the ground load, and the internal pressure is The ground load is transmitted to the first and second pressure chambers of the pair of fluid actuator devices via the second piping, and the magnitude of the ground load is applied to the piston rod of each shock absorber based on the magnitude of the internal pressure from each fluid actuator device. A bending load corresponding to the magnitude of the bending load due to the external force acting on the piston rod is applied. On the other hand, when the car body is tilted in the opposite direction to the turning direction during turning, and the ground load acts on the wheels from vertically upward to the turning direction side, internal pressure is applied to the pressure chamber of the shock absorber to the left and right side due to the car body tilt. The internal pressures generated differently in the shock absorbing device are transmitted to the first and second pressure chambers of each fluid actuator device via first and second piping, respectively, so that the internal pressures are transferred from each fluid actuator device to its first and second pressure chambers. Based on the difference in the internal pressure of the pressure chambers, a bending load is applied to the piston rod of each shock absorber in accordance with the magnitude of the bending load due to the external force acting on the piston rod and in a direction opposite to the acting direction. .

(Effects of the Invention) Therefore, according to the present invention, even if the bending load due to an external force acting on the piston rod of the shock absorber changes as the ground load changes in magnitude and direction, the magnitude and Since a bending load corresponding to the direction is applied to the piston rod from the fluid actuator device and the bending load can be reliably offset, the frictional resistance at the sliding contact between the piston rod and the cylinder due to the bending deformation of the piston rod can be effectively reduced. The damping function of the shock absorber against the vertical vibration of the wheel can be fully demonstrated.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

1 and 2 show a strut-type front suspension of an automobile equipped with a hydroneumatic mechanism according to an embodiment of the present invention, in which 1 is a vehicle body, 2 and 3 are left and right wheels (front wheels) 4L, 4
The wheel support members 5 and 6 rotatably support the respective wheels R, and 5 and 6 are suspension arms arranged in the vehicle width direction corresponding to the respective wheels 4L and 4R, and the inner ends of the respective suspension arms 5 and 6 are The outer end portions are rotatably attached to the frames 1a, 1a of the vehicle body 1, and the outer end portions are rotatably attached to the lower portions of the wheel support members 2, 3, respectively.

Reference numerals 7 and 8 denote a pair of left and right shock absorbers arranged vertically inside each of the wheels 4L and 4R, and each of the shock absorbers 7 and 8 has a pressure chamber 10a defined therein by a piston 9. and a piston rod 11 that is connected to the piston 9 and extends upward from the opening 10b of the cylinder 10, and the lower part of the cylinder 10 is connected to the wheel support member 2,
The upper part of the piston rod 11 is swingably supported by the vehicle body 1 via a mount rubber 12, and the vertical vibration of the wheels 4L, 4R is damped by the expansion and contraction movement of the piston rod 11 with respect to the cylinder 10. It is composed of Here, ground load F1 acting on each wheel 4L, 4R
Or, for F2, reaction forces F11 and F1 are applied to the vehicle body 1 via the shock absorbers 7 and 8 and suspension arms 5 and 6 corresponding to the respective wheels 4L and 4R.
2 or F21, F22, each shock absorber 7, 8 is supported by wheels 4L, 4.
In order to avoid interference with R, when the vehicle is at rest, the center axis 1 of the left shock absorber 7 is directed downward from the line of action 2 of the reaction force F11 acting on the shock absorber 7 from the vehicle body 1, as shown in FIG. It is located closer to the inside of the vehicle width.

Further, 13 and 14 each have a hydraulic chamber 15 inside.
A pair of left and right accumulators are constituent members of a hydroneumatic mechanism having a gas chamber 15a and a gas chamber 15b. communicates with a pressure chamber 10a in the cylinder 10 via a passage 16;
By applying a predetermined pressure to the pressure chamber 10a and changing the reference length of the shock absorbers 7 and 8 (the length when the piston rod 11 is not expanding or contracting),
It is configured to adjust vehicle height and vehicle body posture.

As a feature of the present invention, the upper end portions of the piston rods 11 of the shock absorbers 7 and 8 are each extended upward from the mounting surface of the vehicle body 1, and each of the extended portions 11a and 11a is provided with a lever extending in the vehicle width direction. 17, 18 are fixed at their inner ends, and at the outer ends of each lever 17, 18 there is a pair of left and right hydraulic cylinder devices 19, which act as fluid actuator devices that apply a bending load to the piston rod 11.
20 are provided. Each hydraulic cylinder device 1
9 and 20 are each fixedly supported by the vehicle body 1, and as shown in detail in FIG.
2a and a second pressure chamber 22b.
2, one end is connected to the piston 21, and the other end (tip) is connected to the cylinder 22 from the second pressure chamber 22b side.
The piston rod 23 is provided with an outwardly extending piston rod 23, and the tip end of the piston rod 23 is rotatably connected to the outer end of each of the levers 17, 18. Here, the expansion and contraction movement of the piston rod 23 with respect to the cylinder 22 is caused by the total pressure in the expansion direction of the piston rod 23 acting on the piston 21 from the first pressure chamber 22a side by its internal pressure and the second pressure chamber 22a.
The pressure receiving area of the piston 21 on the second pressure chamber 22b side is smaller than that of the first pressure chamber 22a. The pressure receiving area of the piston 21 on the side is smaller by the cross-sectional area of the piston rod 23.

In addition, the first hydraulic cylinder device 19 on the left side
The pressure chamber 22a is communicated with the pressure chamber 10a of the cylinder 10 of the right shock absorber 8 via the first hydraulic pipe 24 and the hydraulic passage 16 of the piston rod 11 of the right shock absorber 8, and the second pressure chamber 22b is connected to the pressure chamber 10a of the cylinder 10 of the right shock absorber 8. It communicates with the pressure chamber 10a of the cylinder 10 of the left shock absorber 7 via the second hydraulic pipe 25 and the hydraulic passage 16 of the piston rod 11 of the left shock absorber 7. On the other hand, the right hydraulic cylinder device 20
The first pressure chamber 22a is connected to the cylinder 10 of the left shock absorber 7 via the first hydraulic pipe 26 and the hydraulic passage 16 of the piston rod 11 of the left shock absorber 7.
The second pressure chamber 10a is in communication with the second pressure chamber 2.
2b is the second hydraulic pipe 27 and the right shock absorber 8
The pressure chamber 10a of the cylinder 10 of the right shock absorber 8 is connected via the hydraulic passage 16 of the piston rod 11 of
is communicated with. The piping structure 28 consisting of the hydraulic piping 24 to 27 and the hydraulic passages 16, 16 allows the pair of left and right hydraulic cylinder devices 19, 2
0 is a convex bending outward in the vehicle width due to the pressure generated in the pressure chamber 10a of the shock absorber 10 on the opposite side of the hydraulic cylinder device, with respect to the piston rod 11 of the shock absorber 10 connected to the hydraulic cylinder device. A load is applied, and a convex bending load is applied inward in the vehicle width by the pressure generated in the pressure chamber 10a of the shock absorber 10 on the same side as the hydraulic cylinder device.

In addition, in FIG. 4, 29 is a hydraulic cylinder device 19,
Piston rod 11 and cylinder 22 in 20
The cover member 29 is a cover member attached to cover the sliding contact portion (opening of the cylinder 22) with the cylinder 22, and the cover member 29 is flexible and does not interfere with the expansion and contraction movement of the piston rod 22 with respect to the cylinder 22. I've learned not to come.

Next, to explain the effects of the above embodiment, when traveling straight, the ground loads F1 and F2 act vertically upward on the wheels 4L and 4R as shown in FIG. Approximately equal internal pressures are generated in the pressure chambers 10a according to the magnitudes of the ground loads F1 and F2, respectively.

At this time, each of the above-mentioned shock absorbers 7 and 8 has its center axis 1 from the vehicle body 1 to the ground loads F1 and F2, as when the automobile is in a stationary state.
Since the reaction forces F11 and F21 acting on the shock absorbers 7 and 8 are located downward and inward in the vehicle width from the line of action 2 of the reaction forces F11 and F21, a component force of the reaction forces F11 and F21 is applied to the upper part of the piston rod 11 of each shock absorber 7 and 8 (towards the vehicle body 1). mounting position)
A lateral force perpendicular to the center axis 1 in the outward direction of the vehicle width acts almost equally on the piston rod 11, and a convex bending load inward in the vehicle width direction corresponding to the magnitude of the ground loads F1 and F2 acts on the piston rod 11.

On the other hand, the first and second pressure chambers 22 of each of the left and right hydraulic cylinder devices 19, 20 apply a bending load to the piston rod 11 of each shock absorber 7, 8.
a, 22b, internal pressures corresponding to the magnitudes of the ground loads F2, F1 of the pressure chambers 10a of the respective shock absorbers 8, 7 are transmitted via the piping structure 28. Each hydraulic cylinder device 19, 20 via levers 17 and 18 to the piston rods 11 of each of the shock absorbers 7 and 8 in a direction that offsets the bending load due to the lateral force acting on the piston rods 11 and corresponding to the magnitude of the ground loads F1 and F2. In other words, a convex bending load is applied outward in the vehicle width corresponding to the magnitude of the bending load due to the lateral force.

On the other hand, when turning, for example, when turning to the right, the ground loads F1 and F2 act on the wheels 4L and 4R tilting from vertically upward to the right side in the turning direction to resist centrifugal force, as shown in Fig. 1. At the same time,
Different internal pressures are generated in the pressure chambers 10a, 10a of the left and right shock absorbers 7, 8 due to the inclination of the vehicle body 1, and the internal pressure of the pressure chamber 10a of the left shock absorber 7, which is the outer side of the turn, is This becomes higher than the internal pressure of the pressure chamber 10a of the right shock absorber 8.

At this time, the reaction force F11 acting on the left shock absorber 7 is tilted inward in the vehicle width compared to when the vehicle is at rest as the ground load F1 is tilted to the right from vertically upward, and its line of action is 2 approaches the center axis 1 of the shock absorber 7, the lateral force acting on the upper part of the piston rod 11 of the shock absorber 7 as a component of the reaction force F11 in the outward direction of the vehicle width perpendicular to the center axis 1 becomes smaller. The bending load convex inward in the vehicle width due to the lateral force at No. 11 is reduced. In particular, when making a sharp turn, the reaction force F11
The line of action 2 of the piston rod 1 is inclined downwardly and inward in the vehicle width with respect to the central axis 1 of the shock absorber 7.
The bending load due to the lateral force at 1 acts in a direction opposite to that when the vehicle is at rest, that is, in a direction that bends the piston rod 11 in a convex shape outward in the width direction of the vehicle. on the other hand,
Conversely, the reaction force F21 acting on the right shock absorber 8 is inclined outward in the vehicle width than when the vehicle is at rest, and its line of action 2 is aligned with the central axis 1 of the shock absorber 8.
Therefore, the lateral force acting on the upper part of the piston rod 11 of the shock absorber 8 in the outward direction of the vehicle width perpendicular to the center axis 1 increases,
The bending load convex inward in the vehicle width due to lateral force increases.

On the other hand, the relatively low internal pressure of the pressure chamber 10a of the right shock absorber 8 is applied to the first pressure chamber 22a of the hydraulic cylinder device 19 that applies a bending load to the piston rod 11 of the left shock absorber 7. The relatively high internal pressure of the pressure chamber 10a of the left shock absorber 7 is transmitted to the second pressure chamber 22b via the hydraulic passage 16 of the piston rod 11 of the left shock absorber 7 and the first hydraulic pipe 24. The total pressure acting on the piston 21 from the first pressure chamber 22a side in the hydraulic cylinder device 19 and the second pressure chamber 2 are transmitted through the eleven hydraulic passages 16 and the second hydraulic piping 25.
Since the difference between the total pressure acting on the piston 21 from the 2b side is smaller than that during the above-mentioned straight traveling, the hydraulic cylinder device 19 is moved from the hydraulic cylinder device 19 to the piston rod 11 of the left shock absorbing device 7. A bending load of a magnitude corresponding to the reduction in bending load due to the applied lateral force is applied. When the line of action 2 of the reaction force F11 acting on the shock absorber 7 coincides with the central axis 1 of the shock absorber 7 during sharp turning, the hydraulic cylinder device 1
Piston 21 from the first pressure chamber 22a side at 9
If the difference between the total pressure acting on the piston 21 from the second pressure chamber 22b side is set to zero, the bending load due to the lateral force acting on the piston rod 11 of the shock absorber 7 will be reduced. If the direction of action is reversed from when the vehicle is stationary, the left shock absorber 7 from the hydraulic cylinder device 19
As the direction of the bending load due to the lateral force is reversed, a bending load is applied to the piston rod 11 in the direction opposite to that when the vehicle is at rest. On the other hand, the first pressure chamber 22a of the hydraulic cylinder device 20 that applies a bending load to the piston rod 11 of the right shock absorber 8 is connected to the pressure chamber 10 of the left shock absorber 7.
The relatively high internal pressure of
and the second pressure chamber 22b.
, the relatively low internal pressure of the pressure chamber 10a of the right shock absorber 8 is transmitted via the hydraulic passage 16 of the piston rod 11 of the shock absorber 8 and the second hydraulic pipe 27, thereby causing the hydraulic cylinder device 2
Piston 21 from the first pressure chamber 22a side at 0
Since the difference between the total pressure acting on the piston 21 from the second pressure chamber 22b side is larger than when traveling straight ahead, the piston rod 11 of the right shock absorber 8 is removed from the hydraulic cylinder device 20.
A bending load corresponding to an increase in the bending load due to the lateral force acting on the piston rod 11 is applied to the piston rod 11 .

In this way, the magnitude and direction of the bending load due to the external force (lateral force) acting on each piston rod 11 of the pair of left and right shock absorbers 7 and 8 fluctuate as the magnitude and direction of the ground load change. too,
A pair of hydraulic cylinder devices 19 and 20 apply a bending load to each piston rod 11 of the shock absorbers 7 and 8 in a direction that offsets the bending load caused by the external force and in accordance with its magnitude, thereby reducing the bending load. Since this can be reliably offset, the bending deformation of each piston rod 11 due to the bending load is prevented, and the frictional resistance at the sliding contact portion between the piston rod 11 and the cylinder 10 (the opening 10b of the cylinder 10) is effectively reduced. Therefore, due to the smooth expansion and contraction movement of the piston rod 11, the damping function of the shock absorbers 7 and 8 against the vertical vibration of the wheels 4L and 4R and the vehicle height adjustment function as a hydroneumatic mechanism can be sufficiently ensured. .

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications. For example, in the above embodiment, the present invention was applied to a strut-type front suspension of an automobile, but it goes without saying that it can be similarly applied to a strut-type rear suspension of an automobile.

In addition, when applying the present invention to both front and rear suspensions, the first pressure chamber of one fluid actuator device is controlled by the pressure of the shock absorber to which the bending load is applied by the other fluid actuator device. A piping structure that communicates with the chamber and connects the second pressure chamber of each fluid actuator device to the pressure chamber of the shock absorber to which the bending load is applied by the fluid actuator device is provided for each front suspension and rear suspension. In addition to providing two parallel suspensions, two may be provided intersecting between the front suspension and the rear suspension.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a schematic diagram showing the overall structure of a strut-type front suspension for an automobile in a turning state; FIG. 2 is a partially cutaway front view showing the main parts; FIG. 3 is a schematic view of the left wheel side portion of the strut-type front suspension when the vehicle is at rest, and FIG. 4 is a longitudinal sectional side view of the hydraulic cylinder device. 1...Vehicle body, 2, 3...Wheel support member, 4L,
4R...Wheel, 7,8...Buffer device, 10a...
Pressure chamber, 11... Piston rod, 17, 18...
...Lever, 19, 20...Hydraulic cylinder device (fluid actuator device), 21...Piston, 2
2... Cylinder, 22a... First pressure chamber, 22b
...Second pressure chamber, 23...Piston rod, 2
4, 26...first hydraulic piping, 25,27...second
Hydraulic piping.

Claims (1)

[Scope of Claims] 1. A pair of left and right wheels, which are provided inside the vehicle body of each wheel corresponding to the left and right wheels, each having a lower portion fixed to a wheel support member and an upper portion swingably supported by the vehicle body. a shock absorber; a pair of left and right fluid actuator devices each having a first pressure chamber and a second pressure chamber facing each other, each connected to a piston rod of each of the shock absorbers and supported by the vehicle body; a first pipe that communicates each first pressure chamber with a pressure chamber of the shock absorber on the opposite side of the fluid actuator device; and a first pipe that connects a second pressure chamber of each of the fluid actuator devices with a pressure chamber of the shock absorber on the same side as the fluid actuator device; and a second pipe communicating with the pressure chamber of the fluid actuator device, and each of the fluid actuator devices has a piston rod of the shock absorber on the opposite side of the fluid actuator device, with respect to a piston rod of the shock absorber connected to the fluid actuator device. The pressure generated in the pressure chamber applies a convex bending load outward in the vehicle width, and the pressure generated in the pressure chamber of the shock absorber on the same side as the fluid actuator device applies a convex bending load inward in the vehicle width. A strut-type suspension for an automobile, characterized in that it is configured to. 2. The fluid actuator device includes a cylinder having a first pressure chamber and a second pressure chamber opposing each other with a piston in between, and a piston rod having one end connected to the piston and the other end extending outside the cylinder. A strut-type suspension for an automobile according to claim 1, wherein the other end of the piston rod of the hydraulic cylinder device is connected to the tip of a lever fixed to the piston rod of the shock absorber.