JPH07174183A - Hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To automatically adjust prescribed damping force, needless to say, and to prevent a high cost of itself from being caused, and further to prevent a rise of the cost from being caused as a device total unit even in the case that a device is utilized as a suspension device. CONSTITUTION:A device is formed such that extension/pressure side bypass paths having subvalves 6, 7 in respective sides by respectively detouring extension/pressure side damping valves 4, 5, arranged in a piston 3, are selectively opened/closed when resonance moved a spool 21, inserted in a cylinder body 1 and interposed in the periphery of a rod of successively providing the piston 3 to form a resonance unit, to high/low adjusting generating damping force.

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 suitable for use in a vibration damping device such as a suspension device in a vehicle.

[0002]

2. Description of the Related Art For example, a hydraulic shock absorber, which is arranged between an axle of a vehicle and a vehicle body and constitutes a suspension device of the vehicle, prevents a vibration from a road surface from being transmitted to the vehicle body when the vehicle is running. In addition to being configured to prevent unnecessary shaking of the vehicle body.

In particular, in recent years, hydraulic shock absorbers are often constructed so that the generated damping force can be automatically adjusted in height so that the driver can concentrate on the operation. It is configured such that the generated damping force is adjusted to a low level by a controller that operates based on the detection values from various installed sensors.

In this case, in the hydraulic shock absorber, for example, the damping force generating portion has a control valve,
The control valve is configured to perform a predetermined operation by driving an actuator, and to adjust the damping force generated by the damping force generation unit to a high or low level, that is, to change or adjust the damping force in a hard or soft manner.

Therefore, in the above-mentioned general-purpose hydraulic shock absorber, the structure of the hydraulic shock absorber itself tends to be complicated,
Therefore, there is a problem that the cost of the hydraulic shock absorber itself tends to increase due to an increase in the number of parts and the number of assembly steps.

Further, when such a hydraulic shock absorber is used in a suspension device, it is indispensable to dispose a sensor and a controller, and there is a disadvantage that the cost of the entire device is likely to increase.

The present invention was devised in view of the above-mentioned circumstances, and the purpose thereof is, of course, that so-called predetermined damping force adjustment can be automatically performed, and the cost of the invention itself. It is an object of the present invention to provide a hydraulic shock absorber that does not cause a rise in height, and that does not cause an increase in the cost of the entire device even when used as a suspension device.

[0008]

In order to achieve the above-mentioned object, the structure of the present invention is applied to the tip of a rod body which is set in a vehicle body side member which is projected and retracted with respect to a cylinder body set in an axle side member. The rod side chamber and the piston side chamber, which are partitioned in the cylinder body by the continuous piston, can communicate with each other via the expansion side damping valve and the compression side damping valve provided on the piston, while the expansion side damping valve is In a hydraulic shock absorber capable of communicating with each other via a bypass side bypass passage and a pressure side bypass passage bypassing a compression side damping valve, an extension side sub-valve is provided at a downstream end of the extension side bypass passage. , A pressure side sub-valve is disposed at the upstream side end of the pressure side bypass passage, and the upstream end of the extension side bypass passage and the downstream side end of the pressure side bypass passage form a horizontal hole that is opened vertically in two steps in the rod body. And the rod side chamber is communicated with the rod side chamber respectively, and a spool is interposed slidably in the axial direction of the rod body under the interposition of upper and lower springs around the rod body in the rod side chamber. At the same time, the upstream side end of the extension side bypass passage and the downstream side end of the pressure side bypass passage are respectively opened, while the downstream end of the pressure side bypass passage is closed when the spool rises,
It is assumed that the upstream side end of the extension side bypass passage is formed in a closed state when the spool descends.

Preferably, the natural frequency of the spool and the pair of upper and lower springs is about
Natural frequency composed of the vehicle body and suspension spring (1-2H
z).

[0010]

Therefore, when the rod body as the vehicle body side member is in a stationary state, even if the cylinder body as the axle side member is moved up and down due to road surface vibration, the spool mounted on the rod body is
It is kept stationary on the outer circumference of the rod body.

At this time, however, the piston relatively slides in the cylinder body, and the rod-side chamber and the piston-side chamber communicate with each other through the expansion-side damping valve and the compression-side damping valve, The expansion-side bypass passage and the compression-side bypass passage are connected, but the extension-side sub-valve and the compression-side sub-valve are also used for communication.

Therefore, at this time, the damping force generated in the hydraulic shock absorber becomes low, that is, the soft damping force.

On the other hand, when the rod body, which is the vehicle body side member, is vertically moved by vibration, the spool mounted on the rod body is slid on the outer periphery of the rod body in the rod side chamber due to its inertia.

When the spool resonates when the rod body vibrates, and when the spool descends on the outer periphery of the rod body due to this resonance, the upstream side of the extension side bypass passage opening to the outer periphery of the rod body in the rod side chamber. The end is closed and the extension side bypass path is blocked.

As a result, the obstruction of the extension side bypass passage cuts off the communication of the rod side chamber with the piston side chamber via the extension side sub-valve, and allows the communication of the rod side chamber with the piston side chamber only through the extension side damping valve. To be done.

Further, when the spool is raised on the outer periphery of the rod body due to resonance, the downstream end of the pressure side bypass passage opening to the outer periphery of the rod body in the rod side chamber is closed and the pressure side bypass passage is closed. It

As a result, the closing of the pressure side bypass passage blocks the communication of the piston side chamber with the rod side chamber via the pressure side sub-valve, and the communication of the piston side chamber with the rod side chamber is permitted only through the pressure side damping valve.

Therefore, when the bypass passage is closed due to the resonance of the spool interposed in the rod body, the communication between the rod side chamber and the piston side chamber is realized only via the expansion side damping valve or the compression side damping valve. At this time, the damping force generated in the hydraulic shock absorber is high, that is, the damping force becomes hard.

When the spool closes one of the bypass passages, the other bypass passage is brought into the communicating state. Therefore, when the extension side damping force becomes hard, the compression side damping force becomes soft and the compression side damping force becomes hard. When becomes, the extension side damping force becomes soft.

[0020]

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 is assumed that the structure is the same as that of a so-called conventional hydraulic shock absorber, and therefore, in the following, the main part of the present invention will be mainly described, and other structures will be described as necessary. I will explain.

That is, as shown in FIG. 1, in the hydraulic shock absorber according to the embodiment of the present invention, the cylinder body 1 is formed by the piston 3 connected to the tip of the rod body 2 which is retracted from the cylinder body 1. A rod side chamber A and a piston side chamber B are defined therein.

The rod side chamber A and the piston side chamber B
Is communicable with each other via the expansion side damping valve 4 and the compression side damping valve 5 provided in the piston 3,
The expansion side sub-valve 6 located at the downstream side end of the expansion side bypass passage bypassing the expansion side damping valve 4 and the compression side sub-valve 7 located at the upstream side end of the compression side bypass passage bypassing the compression side damping valve 5. It is said that they can communicate with each other.

In this embodiment, the cylinder body 1 is set as a member on the axle side, and is, for example, a cylinder in a hydraulic shock absorber having a single cylinder structure or an inner cylinder in a hydraulic shock absorber having a double cylinder structure. ,,.

In this embodiment, the rod body 2 is set as a member on the vehicle body side, and constitutes, for example, a piston rod that is retracted from the cylinder or the inner cylinder.

Although not shown, the inside of the upper end of the cylinder body 1 is constructed so that the rod body 2 is inserted into the shaft-sealing structure, and also has a necessary sealing member and the like between the rod body 2 and the rod body 2.

Also, although not shown, the piston side chamber B has a free piston for partitioning the gas chamber behind it, or a reservoir chamber partitioned between the outer cylinder and the outer cylinder distributed on the outer peripheral side of the inner cylinder. It is in communication with the base valve part.

Extension side damping valve 4 and compression side damping valve 5
In this embodiment, each of them is composed of an annular leaf valve, and the expansion side damping valve 4 has a downstream side end which is a lower end in the drawing of the expansion side port 3a for opening the piston 3 and a compression side damping valve. The valve 5 is a pressure side port 3b for opening the piston 3.
In the figure, the downstream side ends, which are the upper ends, are arranged so as to be openably and closably closed, that is, the inner peripheral end is fixed and the outer peripheral end is free.

A valve stopper 4a, which also functions as a valve stopper of an expansion-side sub-valve 6 described later, is provided behind the expansion-side damping valve 4 under the interposition of a spacer 4b, and behind the compression-side damping valve 5. Means that the valve stopper 5a, which also functions as a guide member constituting the vibrating body mechanism 20 to be described later, has a spacer 5b
Are distributed under the intermediation of.

Expansion side sub-valve 6 and compression side sub-valve 7
Also, in this embodiment, each is composed of an annular leaf valve, and similarly to the expansion side damping valve 4 and the compression side damping valve 5 described above, the inner peripheral end is fixed and the outer peripheral end is free. There is.

By the way, the expansion side bypass passage for arranging the expansion side sub-valve 6 at its downstream end and the compression side bypass passage for arranging the compression side sub-valve 7 at its upstream end are the rod bodies 2 in this embodiment. Is formed between the vicinity portion 2b, which is the vicinity of the tip spigot portion 2a, and the piston nut 8 screwed to the tip threaded portion 2c of the rod body 2.

That is, the rod body 2 has a vertical hole 2d which is opened in the axial core portion from the vicinity portion 2b to the tip spigot portion 2a and the lower end of which is open to the piston side chamber B side. The vicinity portion 2b is provided with lateral holes 2e and 2f which are opened vertically in two stages so as to communicate with the vertical hole 2d and communicate with the rod side chamber A.

Incidentally, the interval formed between the lateral hole 2e and the lateral hole 2f is appropriately set according to the structure of the vibrating body mechanism 20 described later, which will be described later.

On the other hand, the piston nut 8 is assumed to be formed in a so-called headed cylindrical shape in this embodiment, and this has a threaded end portion of the rod body 2 through the upper end portion 8a which is the head thereof. When it is screwed to 2c, its inner space 8
The lower end of the vertical hole 2d is opened in b.

The piston nut 8 has an extension side port 8c at its upper end 8a.
The extension side sub-valve 6 is provided at the downstream end which is the upper end in the figure of c.
Are adjacent to each other so that they can be opened and closed.

A valve stopper 4a of the expansion-side damping valve 4 is arranged behind the expansion-side sub-valve 6 with an intervening spacer 6a.

On the other hand, the piston nut 8 has a pressure side sub-valve 7 disposed inside the lower end portion 8d.

That is, the inner periphery of the lower end 8d of the piston nut 8 is closed to close the inner space 8b and the piston side chamber B.
The valve disc 9 is caulked and fixed so as to cut off communication with the pressure side sub-valve 7 which can be opened and closed at the downstream side end which is the upper end of the pressure side port 9a for opening the valve disc 9 in the figure. I am letting you.

On the rear side of the pressure side sub valve 7,
The valve stopper 7a is arranged under the interposition of the spacer 7b.

The pressure side sub valve 7 and the valve stopper 7
The a and the spacer 7b are interposed on the outer periphery of the fixed pin 10 inserted into the shaft core of the valve disc 9, and the lower end of the fixed pin 10 is caulked to form the valve disc 9
Is integrated into a so-called block.

By the way, a vertical hole 2d is formed in the piston nut 8, that is, in the inner space 8b and in the rod body 2.
In this embodiment, the inside is divided into so-called extension side and compression side by the partition member 11.

That is, the partition member 11 basically has a flange portion 11a which divides the inner space 8b into upper and lower portions, and a vertical hole which is continuous with the shaft core portion of the flange portion 11a and is opened in the rod body 2. It has a cylindrical portion 11b that is present inside 2d and a bulging portion 11c formed on the outer periphery of the upper end of the cylindrical portion 11b.

The lower end of the tubular portion 11b is opened at the center of the flange portion 11a, and the upper end of the tubular portion 11b is provided with a vertical hole 2d.
Of the cylindrical portion 11b has an appropriate gap between the outer periphery of the cylindrical portion 11b and the inner periphery of the vertical hole 2d, and the outer periphery of the bulging portion 11c is liquid-tight in the inner periphery of the vertical hole 2d. Will be adjacent to.

The outer periphery of the bulging portion 11c is formed between the lateral holes 2e and 2f which are vertically opened in the rod body 2 and are open to the inner periphery of the vertical hole 2d. It is said to be adjacent to the inner circumference of the stroke part.

Therefore, the inner hollow portion 8b in the piston nut 8 is
The expansion side communicating with the expansion side sub-valve 6 and the compression side sub-valve 7
And a pressure side communicating with.

Further, the cylindrical portion 11b of the partition wall member 11
Thus, the inside of the vertical hole 2d of the rod body 2 is divided into an expansion side communicating with the expansion side sub-valve 6 and a compression side communicating with the compression side sub-valve 7.

The partition wall member 11 has a flange portion 11
The outer peripheral end of a is sandwiched between a stepped portion 8e formed on the inner periphery on the lower end side of the piston nut 8 and a cylindrical spacer 12 whose lower end is locked to the outer peripheral end of the valve disc 9. .

As a result, in this embodiment, the rod side chamber A is opened in the rod body 2 and the upper lateral hole 2e and the cylindrical portion 1 are formed.
1b communicates with the downstream side of the pressure side sub-valve 7 via a pressure side bypass passage formed on the inner peripheral side of 1b and the lower side of the flange portion 11a, and the rod body 2 is provided with a lateral hole 2f at the lower stage of the opening.
The extension side sub-valve 6 is provided via an extension side bypass passage formed on the outer peripheral side of the tubular portion 11b and on the upper side of the flange portion 11a.
Will communicate with the upstream side of.

On the other hand, the vibrating body mechanism 20 has a spool 21 slidably provided on the outer periphery of the rod body 2 in the rod side chamber A, and the spool 21 is arranged above and below the spool 21. The spool 21 is sandwiched between a pair of springs 22 and 23 that bias the spool 21 in the forward direction.

The natural frequency of the vibrating body in the vibrating body mechanism 20, that is, the vibrating body composed of the spool 21 and the pair of upper and lower springs 22 and 23 is approximately the vehicle body and the suspension spring (not shown). It is set near the natural frequency (1 to 2 Hz) of the vibrating body constituted by.

Therefore, in the vibrating body mechanism 20, when the spool 21 is at rest, the spool 21 has the upstream end of the extension side bypass passage, that is, the lateral hole 2f in the open state, and the downstream side of the pressure side bypass passage. The end, that is, the lateral hole 2e is left open.

When the spool 21 is at its maximum rise, the downstream side end of the pressure side bypass passage, that is, the lateral hole 2e is closed, and at the time of its maximum fall, the upstream side end of the extension side bypass passage, that is, the lateral side. The hole 2f will be closed.

By the way, the spool 21 has an annular groove 2 which is formed on the inner peripheral surface thereof and faces the lateral hole 2f when the spool 21 stands still.
1a and also has a communication hole 21b which is opened on the outer peripheral side thereof and which communicates the annular groove 21a with the rod side chamber A.

The spool 21 has the annular groove 2
By forming 1a, the so-called land portion 21c remaining on the inner peripheral surface on the upper end side is set so as to match the space formed between the lateral holes 2e and 2f. There is.

Incidentally, the spool 21 is a guide member formed in the shape of a cylinder with a bottom, that is, the spool 21 is accommodated in the valve stopper 5a in such a manner that the outer periphery on the lower end side is in sliding contact with the valve stopper. It is supposed that the damping chamber 24 is formed between it and 5a.

The damping chamber 24 is communicated with the rod-side chamber A through an orifice 25 that is opened at the bottom of the valve stopper 5a.

The spring 22 adjacent to the spool 21 from above is locked at its upper end by a spring receiver 14 adjacent to the lower end of a cushion member 13 arranged on the outer periphery of the rod body 2 and attached to the spool 21. The lower end of the spring 23 adjacent from the lower side is locked to the inner bottom of the valve stopper 5a.

In the hydraulic shock absorber according to this embodiment formed as described above, the rod body 2 serving as the vehicle body side member
In the stationary state, even if the cylinder body 1 as the axle side member is vertically moved due to road surface vibration, the spool 21 interposed in the rod body 2 is kept stationary on the outer periphery of the rod body 2.

At this time, the piston 3 relatively slides in the cylinder body 1 so that the rod-side chamber A and the piston-side chamber B are extended side damping valve 4 and compression side damping valve 5.
While it is communicated via the expansion side bypass path and the compression side bypass path, it is also communicated via the expansion side sub-valve 6 and the compression side sub-valve 7.

Therefore, at this time, the damping force generated in the hydraulic shock absorber is low, that is, a soft damping force.

On the other hand, the rod body 2 which is the vehicle body side member
Is moved up and down by vibration, the spool 21 mounted on the rod body 2 is slid on the outer circumference of the rod body 2 in the rod side chamber A due to its inertia.

When the rod body 2 vibrates, the spool 2
1 resonates, and when the spool 21 descends on the outer periphery of the rod body 2 due to this resonance, the upstream end of the extension side bypass passage opening to the outer periphery of the rod body 2 in the rod side chamber A, that is, the rod body. The opening of the lateral hole 2f opened in 2 is closed by the spool 21, and thus the extension side bypass path is closed.

As a result, the communication of the rod side chamber A to the piston side chamber B via the extension side sub-valve 6 is cut off due to the closing of the extension side bypass passage, and the piston side chamber of the rod side chamber A only through the extension side damping valve 4. Communication to B is allowed, and therefore, the extension side damping force is high at this time, that is, hard.

Further, when the spool 21 rises on the outer circumference of the rod body 2 due to resonance, the downstream end of the pressure side bypass passage opening to the outer circumference of the rod body 2 in the rod side chamber A, that is, the rod body 2 opens. The opening of the perforation lateral hole 2e is closed by the spool 21, and thus the pressure side bypass passage is closed.

As a result, the communication of the piston side chamber B to the rod side chamber A via the pressure side sub-valve 7 is blocked by closing the pressure side bypass passage, and the piston side chamber B to the rod side chamber A only through the pressure side damping valve 5. Communication is allowed, and thus the compression damping force is high at this time, that is, hard.

As described above, in this embodiment, the generated damping force becomes hard when the spool 21 closes the bypass passage, and becomes soft when the spool 21 opens the bypass passage. .

Therefore, to this extent, although not shown, the rod body 2 has only one horizontal hole, the partition member 11 is omitted, and the spool 2 is not shown.
Even if the lateral hole and the rod-side chamber are communicated with each other when the vehicle is stationary, it is possible to make the damping force generated when the bypass passage is closed and soft when the bypass passage is opened.

However, in such a setting, when the damping force on one side becomes hard, the damping force on the other side becomes hard, and when the damping force on one side becomes soft, the damping force on the other side also becomes soft. Therefore, as in the case of the embodiment of the present invention, it becomes impossible to set the damping force on one side to be soft when the damping force on the other side is to be hard.

As a result, in the case of this embodiment, when the damping force on one side is made hard, the damping force on the opposite side becomes soft, so that a hard damping force is used to suppress vibration on the spring. In this situation, when the input from the road surface reverses the direction of the relative movement between the piston 3 and the cylinder body 1 on the rod body 2 side, the vibration on the spring is increased rather than softening. When the damping force is generated, the transmission of the input from the road surface to the vehicle body can be minimized.

Therefore, according to this embodiment, it is possible to simultaneously prevent the input from the road surface, that is, the transmission of the vibration to the vehicle body and the prevention of the vehicle body shaking.

[0070]

As described above, according to the present invention, a predetermined damping force is automatically generated at the time of resonance on the spring, and, for example, in a vehicle, while the driver is devoted to steering,
There is an advantage that vibration from the road surface is not transmitted to the vehicle body and unnecessary vibration of the vehicle body can be prevented.

Further, according to the present invention, since the structure of the hydraulic shock absorber itself is not complicated, the cost of the hydraulic shock absorber itself is not increased, and when it is used as a suspension device in a vehicle, for example, the vehicle body side Since various sensors, controllers, etc. are not required to be installed in the device, there is an advantage that the cost of the entire device does not increase.

Further, according to the present invention, for example, even when it is used in a vibration damping device other than a suspension device in a vehicle, it is required to dispose various sensors, controllers, etc. on the mounting side and design changes therefor. Therefore, only the replacement of the hydraulic shock absorber is sufficient, and there is an advantage that its versatility can be expected.

[Brief description of drawings]

FIG. 1 is a sectional view showing a hydraulic shock absorber according to an embodiment of the present invention with a part thereof cut away.

[Explanation of symbols]

 1 Cylinder Body 2 Rod Body 2e, 2f Side Hole 3 Piston 4 Extension Side Damping Valve 5 Pressure Side Damping Valve 6 Extension Side Sub-valve 7 Pressure Side Sub-valve 21 Spool 22, 23 Spring A Rod Side Chamber B Piston Side Chamber

Claims (1)

[Claims] 1. A rod-side chamber and a piston-side chamber that are partitioned in the cylinder body by a piston that is continuous with the tip of a rod body that is set in a body-side member that appears in and out of a cylinder body that is set as an axle-side member, It is possible to communicate with each other via an expansion side damping valve and a compression side damping valve provided on the piston, and through an expansion side bypass path bypassing the expansion side damping valve and a compression side bypass path bypassing the compression side damping valve. In the hydraulic shock absorber that can communicate with each other, an expansion side sub-valve is arranged at a downstream side end of the expansion side bypass passage, and a pressure side sub-valve is arranged at an upstream side end of the pressure side bypass passage, and The upstream end of the extension side bypass passage and the downstream end of the compression side bypass passage are respectively connected to the rod side chamber through lateral holes that are opened vertically in two steps in the rod body, and at the same time, in the rod side chamber. A spool is provided slidably in the axial direction of the rod body under the interposition of springs arranged vertically on the outer periphery of the saddle body, and the upstream side end of the extension side bypass passage and the pressure side bypass passage when the spool is stationary. The downstream ends of the pressure side bypass passages are closed when the spool is raised, and the upstream ends of the extension side bypass passages are closed when the spool is lowered. Hydraulic shock absorber characterized by being formed as