JPH0437296B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a suspension device for supporting an automobile body, a machine tool, etc.

[Background Art] Generally, in a suspension device that uses relative movement between a cylinder filled with oil and a piston,
Relative displacement in the radial direction is restricted between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder, and between the outer circumferential surface of the piston rod and the cylinder. Therefore, friction occurs in this radial direction displacement regulating portion, which causes the vibration transmission rate to increase when the vibration from the vibration generating portion has a minute amplitude.

On the other hand, in a suspension device that closes the space between the inner and outer cylinders with a corded rubber membrane or the like and damps vibrations by resistance passing through an orifice when the inner and outer cylinders are displaced in the axial direction, there is a means for regulating the radial displacement of the inner and outer cylinders. Since there is no such thing, it cannot be used in areas where unbalanced loads are applied.

[Object of the Invention] In consideration of the above facts, the present invention provides a suspension device that can reliably support uneven loads and damp vibrations even in a suspension device that damps vibrations by relative movement in the axial direction between the inner and outer cylinders. The purpose is to obtain a sion device.

[Summary of the Invention] In the suspension device according to the present invention, when vibration is input and the inner and outer cylinders move relative to each other in the axial direction, the first
A pressure change occurs in the liquid chamber, and vibrations are damped by passage resistance when the liquid moves back and forth between the first liquid chamber and the second liquid chamber via the orifice. 1st
A rolling element whose axial relative movement is limited is placed in contact with the inner and outer cylinders between the inner and outer cylinders inside the liquid chamber. The outer cylinder can be moved relative to the outer cylinder in the axial direction with extremely little resistance due to the rotation of the rolling elements. Therefore, according to the suspension device according to the present invention, even if an unbalanced load is applied, the unbalanced load can be reliably supported and vibrations can be appropriately damped.

[Embodiment of the Invention] FIG. 1 shows a suspension device 10 according to an embodiment of the invention.

In this suspension device 10, an outer cylinder 12 and an inner cylinder 14 are arranged coaxially. One end of the outer cylinder 12 is closed with a cover plate 12A.
A connecting rod 16 is fixed to A. This connecting rod 16 is adapted to be connected to, for example, the body of an automobile.

An inner cylinder 14 is inserted from the other end of the outer cylinder 12. A corded rubber membrane 18 as a first rubber membrane is stretched between the outer periphery of the inner cylinder 14 and the end of the outer cylinder 12 to close the gap between the outer cylinder 12 and the inner cylinder 14. ing. This corded rubber membrane 18
is elastically deformed when the outer cylinder 12 and the inner cylinder 14 move relative to each other in the axial direction.

The upper end of the inner tube 14 is closed with a cover plate 14A, and a corded rubber membrane 20 as a second rubber membrane is stretched over the axially central portion to block the upper and lower sides of the inner tube 14. In addition, the lower end of the inner cylinder 14 is connected to a cover plate 14.
It is closed at B.

Here, in the inner cylinder 14, an air chamber 22 is defined between the cover plate 14B and the corded rubber membrane 20, and a first liquid chamber 24 is defined between the corded rubber membrane 20 and the cover plate 14A. On the other hand, the inside of the outer cylinder 12 serves as a second liquid chamber 26.

An orifice 28 is fixed to the cover plate 14A of the inner cylinder 14 and passes through a part of the cover plate 14A. Thereby, the orifice 28 communicates the first liquid chamber 24 and the second liquid chamber 26.

Balls 30 as rolling elements are interposed between the outer periphery of the inner cylinder 14 and the inner periphery of the outer cylinder 12. A recess 32 is formed on the outer periphery of the inner cylinder 14 corresponding to the ball 30, and thereby the amount of movement of the ball 30 in the axial direction of the inner cylinder 14 is regulated by the length of the recess 32. . In this embodiment, the balls 30 are arranged in two stages, upper and lower, with an interval between them. Further, the gap between the inner tube 14 and the outer tube 12 in the portion where the ball 30 is interposed is formed to be larger than the outer shape of the ball 30, so that the ball 30 can freely move up and down. .

A connecting rod 34 is attached to the cover plate 14B of the inner cylinder 14, and the tip of this connecting rod 34 is adapted to be connected to, for example, a wheel shaft of an automobile.

Next, the operation of this embodiment will be explained.

When the connecting rod 34 is connected to the wheel axle and the connecting rod 16 is connected to the vehicle body, the load of the vehicle body is applied to the outer cylinder 12. As a result, the pressure in the first liquid chamber 24 and the second liquid chamber 26 increases, and this pressure is transmitted to the air chamber 22 via the corded rubber membrane 20, so the air chamber 22 contracts and the pressure decreases. It rises to support the vehicle load.

When vibration occurs in the vehicle body or wheels, the outer cylinder 12 and the inner cylinder 14 move relative to each other in the axial direction (vertical direction in FIG. 1). As a result, the first liquid chamber 24 and the second liquid chamber 26
The liquid repeatedly flows from one side to the other through the orifice 28. Therefore, vibrations are damped by the internal resistance of the liquid.

When an unbalanced load having a component other than the axial direction is applied, the balls 30 support the load in the radial direction, so that the outer cylinder 12 and the inner cylinder 14 are accurately coaxially maintained and vibrations are absorbed. Ru.

Since the ball 30 can be moved slightly by the recess 32, if the vibration has a minute amplitude,
When the ball 30 rolls between the outer cylinder 12 and the inner cylinder 14 and has a large amplitude, the ball 30 rolls between the outer cylinder 12 or the inner cylinder 14.
It will slide against. Therefore, when the amplitude is small, rolling friction occurs due to rolling, the resistance force is small, and the vibration transmission rate can be kept low.

FIG. 2 shows a suspension device according to a second embodiment of the invention.

In this embodiment, a retainer 36 is provided on the outside of the inner cylinder 14.
is attached to the retainer 36, and a plurality of balls 38 are accommodated in recesses formed in the retainer 36. These balls 38 are the top balls 3
8 rolls through a circulation guide path (not shown) in the retainer 36 and is guided to the lowest position, then the outer cylinder 1
It constitutes a so-called linear bearing that rolls on the inner peripheral surface of No. 2 and reaches the top stage again. Therefore, even when the outer cylinder 12 and the inner cylinder 14 undergo a large relative movement, this linear bearing rolls against the inner circumferential surface of the outer cylinder 12, and has the role of reducing the vibration transmission rate.

FIG. 3 shows a suspension device according to a third embodiment of the invention. This suspension system is also designed to absorb high-frequency vibrations.

That is, a small chamber 44 provided in a part of the outer cylinder 12 is communicated with the air chamber 22 via a connecting pipe 46.
However, a membrane material 48 is provided in the small chamber 44 to isolate it from the second liquid chamber 26. This membrane material 48 may be any membrane material having nonlinear characteristics, such as a corded rubber membrane. Further, the connecting pipe 46 may be a flexible pipe.

As a result, in this embodiment, even if the orifice 28 becomes clogged during high-frequency vibration, the membrane material 48 deforms, making it possible to change the volume of the second liquid chamber 26, thereby reducing the vibration transmission rate. be able to. Note that since the membrane material 48 has nonlinear characteristics, its deformation amount is limited, and during low frequency vibrations, fluid passage through the orifice 28 is ensured and vibration damping is not hindered.

Note that in this embodiment, the connecting pipe 46 and the small chamber 44
A similar effect can also be obtained by cutting off the connection pipe 46 and omitting the connecting pipe 46.

FIG. 4 shows a suspension device according to a fourth embodiment of the present invention. This embodiment also employs means for absorbing high frequency vibrations.

In this embodiment, regulating plates 50 and 52 are provided in front and behind the membrane material 48 as means for limiting the amount of deformation of the membrane material 48 of the previous embodiment. These regulation plates 5
0 and 52 are provided with through holes 54, so that the liquid pressure in the second liquid chamber 26 and the gas pressure in the connecting pipe 46 can be transmitted to the front and back surfaces of the membrane material 48, respectively. However, the membrane material 48 is attached to the regulating plate 5.
Since the amount of deformation is limited by 0.0 and 52, liquid flow in the orifice is ensured at low frequency and large amplitude, and at the same time, at high frequency and low amplitude, the volume of the second liquid chamber 26 can be changed to absorb vibrations. It's becoming like that.

The rest of the structure is similar to that of the third embodiment, and similar effects can be obtained.

Next, FIGS. 6 and 7 show experimental examples of the present invention in comparison with conventional products. In these experimental examples, 300 kg was applied between the outer cylinder 12 and the inner cylinder 14 of the first embodiment of the present invention.
Applying a pressing load of
A state in which the transmission force (P-P value) due to passing over the protrusion generated by rotating the drum 58 in the direction of arrow A is investigated is shown. (The vehicle speed in FIG. 6 is equal to the circumferential speed of drum 58). In the figure, the conventional product uses a general suspension device composed of a cylinder, a piston, and a coil spring provided on the outer periphery of the cylinder. In addition, Fig. 7 shows the case where the speed (circumferential speed of drum 58) is 60 km/h, and 0 dB =
It is 85.5Kg.

As can be seen from FIGS. 6 and 7, in the experimental example of the present invention, it has become clear that the transmitted force can be reduced and vibrations can be reliably absorbed at any vehicle speed and frequency.

[Effects of the Invention] As explained above, in the suspension device according to the present invention, the rolling elements disposed between the inner and outer cylinders enable relative movement of the inner and outer cylinders in the axial direction while regulating relative displacement in the radial direction. It has an excellent effect of being able to reliably support even uneven loads and damp vibrations.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a suspension device according to the present invention, and FIGS. 2 and 3 correspond to FIG. 1 showing a second and third embodiment of the present invention. 4 is an enlarged partial view showing a fourth embodiment of the present invention, FIG. 5 is a sectional view showing a protrusion used in an experimental example of the present invention, and FIG. 6 is a diagram showing the force transmitted to the vehicle body by passing over the protrusion. FIG. 7 is a diagram showing the transmission force versus frequency when driving over a bump at a vehicle speed of 60 km/h. 10...Suspension device, 12...Outer cylinder, 14
...Inner cylinder, 18...Rubber film with cord (first rubber film), 20...Rubber film with cord (second rubber film),
22... Air chamber (air chamber), 24... First liquid chamber, 26...
Second liquid chamber, 28... Orifice, 30, 38... Ball (rolling element), 40... Rubber.

Claims (1)

[Scope of Claims] 1. An inner and outer cylinder that are relatively movable in the axial direction, a first rubber membrane that connects and closes the inner and outer cylinders, and a second rubber membrane that divides the inside of the inner cylinder into two chambers; a first liquid chamber formed in the outer cylinder and partitioned by the inner cylinder and the first rubber film; and a second liquid chamber formed in the inner cylinder and partitioned by the second rubber film. Vibrations are damped by resistance to passage of the liquid when passing through an orifice interposed between the inner cylinder and the second liquid chamber. A suspension device that supports a load by the internal pressure of an air chamber, which is disposed between an inner and outer cylinder inside the first liquid chamber in contact with the inner and outer cylinders, and is arranged in contact with the inner and outer cylinders, and has an axial relative movement amount with respect to the inner cylinder or the outer cylinder. A suspension device characterized by having rolling elements with limited