JPH07158683A - Hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To provide a hydraulic shock absorber capable of generating damping force as set so as to be optimum in the case of being used as a suspension device in a vehicle. CONSTITUTION:Damping force generating mechanism 10 disposed in an oil passage 5 in a hydraulic shock absorber formed into the so-called one-way structure has a pressure chamber R disposed on the back face side of a leaf valve 16 forming a main valve 10a in the damping force generating mechanism 10 and communicated with the upper reaches side of a pilot valve 10b of the damping force generating mechanism 10, and a first order lag pressure chamber R1 communicated with the pressure chamber R. It is so formed that the first order lag pressure chamber R1 can change its volume.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a hydraulic shock absorber, which is disposed between an axle of a vehicle and a vehicle body, absorbs road surface vibrations of a running vehicle and functions as a suspension device of the vehicle.

[0002]

2. Description of the Related Art Conventionally, there have been various proposals for a hydraulic shock absorber, which is disposed between an axle of a vehicle and a vehicle body and absorbs road surface vibrations of the running vehicle to function as a suspension device of the vehicle.

For example, a hydraulic shock absorber as a conventional example shown in FIG. 2 is continuously provided at the tip of a piston rod 2 which is arranged on the axle side of a vehicle which is projected and retracted with respect to a cylinder 1 which is arranged on the vehicle body side of the vehicle. The rod side chamber A and the piston side chamber B are partitioned in the cylinder 1 by the piston 3 which is formed, and the outer cylinder 4 is disposed on the outer peripheral side of the cylinder 1 and the reservoir is provided between the outer cylinder 4 and the cylinder 1. The chamber C is supposed to be formed.

The hydraulic shock absorber has a piston side chamber B.
Is communicated with the rod side chamber A via an expansion side check valve 3a provided in the piston 3, the rod side chamber A is communicated with a reservoir chamber C via an oil passage 5 disposed outside, and the reservoir chamber C Is a base valve portion 6 located inside the lower end of the cylinder 1.
It is communicated with the piston side chamber B via the pressure side check valve 6a and has a so-called one-way structure in which the hydraulic oil flows only in one direction when the piston 3 slides in the cylinder 1.

In this conventional example, the reservoir chamber C
A pipe P is provided in the rod side chamber A, and the rod side chamber A is communicated with the external oil passage 5 via the pipe P.

On the other hand, the hydraulic shock absorber functions as a damping force generating mechanism for generating a predetermined damping force in the oil passage 5 which allows the working oil from the rod side chamber A to flow toward the reservoir chamber C. A pilot type electromagnetic proportional relief valve 10 is provided.

The pilot type electromagnetic proportional relief valve 10
Is a main valve 10a that generates a predetermined damping force when the hydraulic oil flows from the rod side chamber A, and the main valve 1a.
0a in parallel with the pilot valve 10b for changing the damping force generated in the main valve 10a.

The pilot type electromagnetic proportional relief valve 10 is, for example, as shown in FIG. 3, for example, the main valve 10a and the pilot valve 10b are housed in a housing 12 connected to a solenoid 11. It is formed into a worn form.

To briefly explain, the housing 12 has a valve block 13 inside which the communication holes 12a and 12b communicating with the external oil passage 5 communicate with each other, and the valve block 13 therein.
And a valve guide 14 screwed on the valve guide 14.
And a valve seat 15 sandwiched between the valve block 15 and the valve block 13.

While the pilot valve 10b is housed inside the so-called inside of the valve block 13, the main valve 10a is arranged between the valve guide 14 and the valve seat 15.

The communication hole 12a communicates with the rod side chamber A in the four cylinders 1 through the oil passage 5, and the communication hole 12b communicates with the reservoir chamber C outside the cylinder 1 through the oil passage 5.

The valve seat 15 divides the inside of the housing 12 into an upstream side and a downstream side. The upstream side communicates with the communication hole 12a and the downstream side communicates with the communication hole 12b.

The main valve 10a is capable of opening and closing a downstream side opening which is a lower end in the figure of a port 15a which is opened in the valve seat 15 and enables the upstream side and the downstream side of the valve seat 15 to communicate with each other. Annular leaf valve 1 to close
6 is included.

The leaf valve 16 has an outer peripheral end supported by a spring seat 17 provided adjacent to the rear surface thereof, and the spring seat 17 is provided with a spring 18 arranged on the rear side thereof in a rising direction in the drawing. Urged by
An initial load is applied to the outer peripheral side end of the leaf valve 16.

The leaf valve 16 is arranged such that its inner peripheral end is sandwiched between the valve seat 15 and the valve guide 14 and the inner peripheral end is fixed.

It is assumed that the main valve 10a has a pressure chamber R on the so-called back pressure side of the leaf valve 16, and the oil pressure in the pressure chamber R, that is, the back pressure forces the so-called valve opening of the leaf valve 16. I can change it.

That is, the pressure chamber R communicates with the upstream side of the pilot valve 10b arranged in the valve block 13 through a port 14a formed by a vertical hole and a horizontal hole opened in the valve guide 14. Accordingly, the hydraulic pressure supplied to the pressure chamber R is controlled by the pilot valve 10b.

On the other hand, the pilot valve 10b includes a poppet 19 slidably housed in a vertical hole 13a formed in the shaft core of the valve block 13, and a sliding direction of the poppet 19 and the poppet 19. The tubular sheet 20 is arranged in series with 19 and is fixed to the vertical hole 13a.

The poppet 19 has its tip 19a facing the central through hole 20a of the tubular sheet 20.
The hydraulic oil from the upstream side of the valve seat 15 is allowed to flow through an annular gap formed between 9a and the central through hole 20a.

Further, the poppet 19 is set so as to be advanced by the thrust force from the plunger 11a in the solenoid 11, and the retreat thereof is performed by the tubular sheet 2 described above.
0 through the central through hole 20a of the poppet 19
It is said that the hydraulic pressure acts on a, that is, the hydraulic pressure from the upstream side of the valve seat 15.

Incidentally, the upstream side of the cylindrical seat 20 is connected to the valve block 13 so as to communicate with the chamber 13b opened in the valve block 13 so as to be in series with the vertical hole 13b. The valve block 13 is provided through the opened port 13c and the orifice 21a as a throttle for the opening in the shaft core portion of the plug 21 screwed to the port 13c.
Of the valve seat 15, that is, the upstream side of the valve seat 15.

Further, the downstream side of the tubular seat 20 is provided with a port 13d opened in the valve block 13 through a tip 19a of the poppet 19, an annular groove 13e formed on the outer peripheral side of the valve block 13 and a housing 12. The housing 12 is communicated with the communication hole 12b for perforation through the perforation port 12c.

In the chamber 13b for opening the valve block 13, the port 14 for opening the valve guide 14 is formed.
Vertical holes forming a are communicated with each other.

Therefore, in the conventional pilot type electromagnetic proportional relief valve 10 formed as described above, the excitation of the solenoid 11 is released and the pilot valve 1 is released.
When the poppet 19 at 0b has no thrust, the flow rate of the hydraulic oil passing through the pilot valve 10b increases.

As a result, the hydraulic pressure supplied to the pressure chamber R in the main valve 10a is low, and therefore the leaf valve 16 in the main valve 10a is easily bent, and the damping force generated at that time is low.

On the other hand, when the excitation of the solenoid 11 is maximized and the thrust of the poppet 19 is maximized,
It is possible to make the flow rate of the hydraulic oil passing through the pilot valve 10b almost zero.

As a result, the hydraulic pressure supplied to the pressure chamber R becomes high, and therefore the leaf valve 16 in the main valve 10a becomes difficult to bend, and the damping force generated at that time becomes high.

When the excitation of the solenoid 11 is gradually changed from zero to the maximum, the flow rate of the hydraulic oil passing through the pilot valve 10b is controlled linearly, and therefore, The hydraulic pressure supplied to the pressure chamber R is linearly controlled, and the main valve 10a
The generated damping force at is controlled to be high and low linearly.

As a result, for example, when the hydraulic shock absorber equipped with the pilot type electromagnetic proportional relief valve 10 is disposed between the vehicle body and the axle of the vehicle as a suspension device in the vehicle, the vehicle travels, for example. By controlling the excitation of the solenoid 11 according to the condition of the road surface, it is possible to control the damping force generated in the hydraulic shock absorber to a high or low level, thereby improving the riding comfort of the vehicle and the steering stability. .

[0030]

However, in the conventional hydraulic shock absorber having the pilot type electromagnetic proportional relief valve 10 described above, when it is mounted on a vehicle and functions as a suspension device, the following is performed. Inconvenience is pointed out.

That is, in the conventional pilot type electromagnetic proportional relief valve 10 described above, since the hydraulic pressure supplied to the pressure chamber R is controlled by controlling the flow rate of the pilot valve 10b, the flow rate of the pilot valve 10b is particularly controlled. In the case of a sudden change from the maximum to zero, the supplied hydraulic pressure in the pressure chamber R is suddenly changed from the low value to the highest value.

At this time, the hydraulic pressure supplied to the pressure chamber R becomes instantaneously, but becomes higher than a predetermined maximum value, and the waveform of the control hydraulic pressure at that time becomes a so-called spike waveform, and leaves forming the main valve 10a. There is an inconvenience that the damping force generated by the valve 16 becomes unstable and the riding comfort and steering stability of the vehicle are impaired.

Further, in the conventional pilot type electromagnetic proportional relief valve 10 described above, when the vibration frequency developed in the hydraulic shock absorber is in the high frequency range, the high pressure is supplied to the pressure chamber R and the high pressure is increased. The pressure is stored in the pressure chamber R.

Therefore, the back pressure acting on the leaf valve 16 becomes abnormally high, the damping force generated at the leaf valve 16 becomes abnormally high, and a so-called lumpy damping force is generated. However, there is an inconvenience that the riding comfort in the vehicle is deteriorated.

The present invention was devised in view of the above-mentioned circumstances, and the purpose thereof is to make it possible to generate a damping force as set, which is optimal for use as a suspension device in a vehicle. The purpose is to provide a hydraulic shock absorber.

[0036]

In order to achieve the above-mentioned object, the structure of the present invention has a structure in which a rod side chamber and a piston side chamber are provided in a cylinder by a piston continuously connected to the tip of a piston rod which is retracted from the cylinder. And a reservoir chamber is formed between the cylinder and an outer cylinder arranged on the outer peripheral side of the cylinder, and the piston side chamber is communicated with the rod side chamber through an extension side check valve arranged on the piston. The side chamber communicates with the reservoir chamber via an oil passage distributed outside,
The reservoir chamber is communicated with the piston side chamber via a pressure side check valve provided in the base valve portion, and a predetermined damping force is generated when the hydraulic oil flows from the rod side chamber to the reservoir chamber in the oil passage. A main valve that is provided with a damping force generating mechanism, and that generates a predetermined damping force when the hydraulic fluid flows from the rod side chamber by the damping force generating mechanism,
In a hydraulic shock absorber comprising a pilot valve which is arranged in parallel with the main valve and which changes a damping force generated in the main valve, the pilot valve being provided on a rear side of a leaf valve whose damping force generating mechanism constitutes the main valve. A pressure chamber communicating with the upstream side of the pressure chamber, a pressure chamber having a first-order lag communicating with the pressure chamber, and the pressure chamber having the first-order lag can change its volume. It is supposed to be done.

More specifically, it is assumed that the damping force generating mechanism is composed of a pilot type electromagnetic proportional relief valve, and the pressure chamber with a first-order lag is communicated with a chamber forming a diaphragm structure.

[0038]

Therefore, when the hydraulic shock absorber in which the piston slides in the cylinder expands and contracts, the hydraulic oil from the rod side chamber in the cylinder moves outside the cylinder via the damping force generating mechanism distributed in the oil passage. It flows into the reservoir chamber side.

When the hydraulic oil passes through the damping force generating mechanism, a predetermined damping force is generated on both sides of the main valve by the main valve.

At this time, by controlling the flow rate of the hydraulic oil in the pilot valve, the hydraulic pressure supplied to the pressure chamber in the main valve is controlled to a high or low level, and the damping force generated by the leaf valve constituting the main valve is controlled to a high or low level. Controlled.

When the vibration frequency in the hydraulic shock absorber is in the high frequency range, the pressure chamber is provided with a first-order lag and communicates with the pressure chamber. Is easily released, and generation of high damping force is prevented when the vibration frequency is in the high frequency region.

Further, when the flow rate in the pilot valve is suddenly changed from the maximum to zero, the pressure chamber of the primary delay communicating with the pressure chamber is formed so that its volume can be changed. Sudden change of supply hydraulic pressure, that is,
The sudden rise is stopped.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings, but a hydraulic shock absorber according to one embodiment of the present invention also
Basically, it has the same structure as the hydraulic shock absorber as the conventional example described above.

Therefore, except for the case where it is necessary, the same parts of the configuration will be denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted. Below, different parts in the illustrated embodiment I will explain mainly.

That is, in the hydraulic shock absorber according to this embodiment, the pilot type electromagnetic proportional relief valve 10 as the damping force generating mechanism has a main valve 10a as shown in FIG.
And a pilot valve 10b.

The pilot type electromagnetic proportional relief valve 10 has a pressure chamber R communicating with the upstream side of the pilot valve 10b on the back side of the leaf valve 16 constituting the main valve 10a.

Further, the pilot type electromagnetic proportional relief valve 10 has a first-order lagging pressure chamber R1 communicating with the pressure chamber R.
And the first-order lag pressure chamber R1 is formed so that its volume can be changed.

Explaining a little, the pressure chamber R with the first-order lag is
In this embodiment, reference numeral 1 is formed inside a so-called inside of the valve guide 14 that holds the inner peripheral side end of the leaf valve 16 between it and the valve seat 15.

That is, although the valve guide 14 is formed with a port 14a consisting of a vertical hole and a horizontal hole, the confluent portion of the vertical hole and the horizontal hole forming the port 14a is so-called enlarged and placed therein. A chamber-like space is formed, and the space is set as the pressure chamber R1 with the first-order lag.

The first-order lagging pressure chamber R1 communicates with a volume chamber R3 formed at the lower end of the valve guide 14 so as to open at the bottom surface of the valve guide 14 in the figure.

According to the present invention, the chamber R3 is constructed to have a diaphragm structure.
A partition member movably accommodated inside, that is, in this embodiment, the leaf valves 22 that are stacked divide the interior of the chamber R3 into so-called upper and lower parts.

An O-ring 23, which is an elastic member, is interposed between the outer peripheral side end of the leaf valve 22 and the so-called closed side end 14b of the chamber R3, and the outer peripheral side of the leaf valve 22. The end is locked to the snap ring 24 provided on the inner periphery of the so-called opening side end of the chamber R3 with the shim 25 interposed.

Therefore, in the volume chamber R3 having this diaphragm structure, when the hydraulic pressure in the volume chamber R3, that is, the pressure chamber R1 having the first-order lag is rapidly increased, the leaf valve 22 is By flexing, the volume in the chamber R3 can be expanded, and the sudden increase in hydraulic pressure can be prevented.

At this time, the O-ring 23 is
The leaf valve 22 is allowed to bend and the inside of the chamber R3 is so-called sealed.

On the other hand, the first-order lag pressure chamber R1 naturally functions as a first-order lag pressure chamber because the orifice is arranged on the upstream side thereof. In this embodiment, the leaf valve-shaped orifice member 26 is used.

That is, in this embodiment, the vertical hole forming the port 14a formed in the valve guide 14 is enlarged at a portion near the pilot valve 10b, and the lower end of the enlarged portion is provided. The above-mentioned leaf valve-shaped orifice member 26 is provided.

The orifice member 26 has an orifice 26a opened at the center thereof, and the orifice 26a faces the first-order lagging pressure chamber R1.

Further, the orifice member 26 is located in the enlarged portion and has the spring 2 distributed upstream thereof.
7, the base end of the spring 27 is locked by a perforated stopper 28 screwed to the enlarged portion.

Therefore, in the case where the orifices are arranged and the orifice member 26 is arranged as described above, the orifice 26a in the orifice member 26 is arranged.
It is possible to appropriately select the diameter of the first-order lag, and therefore, it is possible to shift the generation timing of the first-order lag pressure generated in the first-order lag pressure chamber R1 according to the vibration frequency range of the hydraulic shock absorber. Become.

In the hydraulic shock absorber having the pilot type electromagnetic proportional relief valve 10 according to this embodiment formed as described above, when the hydraulic shock absorber in which the piston 3 slides in the cylinder 1 is expanded and contracted. The hydraulic oil from the rod side chamber A in the cylinder 1 flows into the reservoir chamber C side outside the cylinder 1 via the pilot type electromagnetic proportional relief valve 10 which is a damping force generating mechanism arranged in the oil passage 5.

When the hydraulic oil passes through the pilot-operated electromagnetic proportional relief valve 10, a predetermined damping force is generated on both sides of the main valve 10a.

At this time, the main valve 1 is controlled by controlling the flow rate of the hydraulic oil in the pilot valve 10b.
The hydraulic pressure supplied to the pressure chamber R formed behind the leaf valve 16 constituting the valve 0a is controlled to be high or low, and the damping force generated by the leaf valve 16 is controlled to be high or low.

When the vibration frequency of the hydraulic shock absorber is in the high frequency range, the pressure chamber R1 communicating with the pressure chamber R and having a primary delay is provided, so that the hydraulic pressure is not supplied to the pressure chamber R. The leaf valve 16 is easily opened, and generation of high damping force is prevented when the vibration frequency is in the high frequency range.

Further, when the flow rate in the pilot valve 10b is suddenly changed from the maximum to zero, the pressure chamber R1 which is in a primary delay and communicates with the pressure chamber R is formed so that its volume can be changed. A sudden change in the supplied hydraulic pressure in the pressure chamber R, that is, a sudden increase in the hydraulic pressure is prevented.

[0065]

As described above, according to the present invention, the primary-lag pressure chamber communicating with the pressure chamber formed on the back pressure surface side of the leaf valve constituting the main valve of the pilot type electromagnetic proportional relief valve is formed. Therefore, when the vibration frequency in the hydraulic shock absorber is in the high frequency range, it is of course possible to prevent the increase of the hydraulic pressure supplied to the pressure chamber, and to stop the hydraulic pressure supply itself to the pressure chamber. Therefore, it is possible to suppress the damping force generated by the leaf valve to a low state, and the deterioration of the riding comfort and the steering stability of the vehicle due to the unsprung vibration of the vehicle traveling on the road surface can be prevented. There is an advantage that can be prevented.

Further, according to the present invention, the operation of the pilot valve in the pilot type electromagnetic proportional relief valve causes a sudden change in the hydraulic pressure supplied to the pressure chamber, in particular, the hydraulic pressure supplied to the pressure chamber is rapidly increased. Even if there is a situation that occurs, the pressure waveform in the pressure chamber does not cause a so-called spike waveform in which the pressure instantaneously becomes higher than a predetermined maximum value, so that the damping force generated in the leaf valve is stabilized. There are advantages.

Further, according to the present invention, since the orifice member for setting the pressure of the first-order lag in the pressure chamber of the first-order lag is formed in the orifice member, the orifice diameter can be arbitrarily selected. There is an advantage that it is possible to recommend the damping force generated in the leaf valve even before the vibration frequency in the shock absorber reaches the high frequency region.

[Brief description of drawings]

FIG. 1 is a partially cutaway cross-sectional view of a pilot type electromagnetic proportional relief valve that constitutes a damping force generating mechanism in a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a view showing a hydraulic shock absorber as a conventional example in a partially cutaway view and a principle view of a pilot-type electromagnetic proportional relief valve constituting a damping force generating mechanism.

3 is a diagram showing the pilot type electromagnetic proportional relief valve as the damping force generating mechanism in FIG. 2 in the same manner as in FIG.

[Explanation of symbols]

1 Cylinder 2 Piston rod 3 Piston 3a Extension side check valve 4 Outer cylinder 5 Oil passage 6 Base valve part 6a Pressure side check valve 10 Pilot type electromagnetic proportional relief valve constituting damping force generating mechanism 10a Main valve 10b Pilot valve A Rod side chamber B Piston side chamber C Reservoir chamber R Pressure chamber R1 First-order pressure chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuya Masamura 2548 Tsuchida, Kani City, Gifu Prefecture Kayaba Industrial Co., Ltd.Gifu North Factory (72) Inventor Mishima 2548, Tsuchida, Kani City, Gifu Prefecture Kayaba Industrial Company Gifu North factory (72) Inventor Takayuki Katsuta 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Nobuo Hiraiwa 1 Toyota Town, Toyota City, Aichi Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. A rod-side chamber and a piston-side chamber are defined in the cylinder by a piston that is connected to the tip of a piston rod that is projected from and retracted from the cylinder, and the cylinder and an outer cylinder arranged on the outer peripheral side of the cylinder. A reservoir chamber is formed in between, the piston side chamber is communicated with the rod side chamber through an extension side check valve provided in the piston, and the rod side chamber is communicated with the reservoir chamber through an oil passage that is distributed to the outside. A damping chamber that communicates with the piston side chamber through a pressure side check valve provided in the base valve section, and that generates a predetermined damping force when the working oil flows from the rod side chamber to the reservoir chamber in the oil passage. A force generating mechanism is provided, the damping force generating mechanism generates a predetermined damping force when the hydraulic oil flows from the rod side chamber, and a main valve that is parallel to the main valve. In a hydraulic shock absorber having a pilot valve that changes the damping force generated by the valve, the damping force generation mechanism connects the rear side of the leaf valve that constitutes the main valve with the pressure that communicates with the upstream side of the pilot valve. A first-order lag pressure chamber communicating with the pressure chamber, and the first-order lag pressure chamber being formed so that its volume can be changed. Hydraulic shock absorber