JPH05280569A - Hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To improve running stability and comfortableness to ride by selectively outputting a signal of sensor piezoelectric element from a controller by vibrating a senor weight, and vibrating an actuator weight by an actuator piezoelectric element. CONSTITUTION:At the time of vibrating a piston rod 2, a signal is output to a controller C from a sensor piezoelectric element 21 by vibrating a sensor weight 22, and in the controller C, a command signal is not output to an actuator piezoelectric element 23, when a vibration frequency is in above/under spring resonance regions, but output to the piezoelectric element 23 when the vibration frequency is beyond the above spring resonance region and in the under spring resonance region. Since the piezoelectric element 23 is expanded by electrification and contracted by release therefrom, when the command signal from the controller C is an on-off signal for a short time, expansion and contraction of the piezoelectric element 23 are repeated in a short time, to vibrate an actuator weight 24. When the actuator weight 24 is set reverse to the vibration of the piston rod 2, the vibration can be suppressed.

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 optimal for mounting on a vehicle.

[0002]

2. Description of the Related Art A hydraulic shock absorber mounted on a vehicle is generally formed so as to enable sprung mass and unsprung mass to be damped. The damping force is set to a high value when the vibration frequency is in the sprung resonance region a and the unsprung resonance region b, as shown in FIG. 8, for example.

However, when the vibration frequency is in the region c from the sprung resonance region a to the unsprung resonance region b, the damping force, that is, the force transmitted to the vehicle body, is
It is preferable to set the value as low as possible to improve the riding comfort of the vehicle.

Therefore, in recent years, various hydraulic shock absorbers equipped with a so-called high-cut valve that depends on the vibration frequency have been proposed. According to the hydraulic shock absorber equipped with the high-cut valve, the vibration frequency has a sprung resonance range a. Until you pass
The high-cut valve generates a high value of damping force and maintains a large force transmitted to the vehicle body to enable the vibration suppression on the spring, while the vibration frequency exceeds the resonance range a on the spring. The damping force generated by the high-cut valve is set to a low value to suppress the force transmitted to the vehicle body (see the broken line portion in FIG. 8), thereby making it possible to improve the riding comfort of the vehicle.

[0005]

However, in the hydraulic shock absorber equipped with the high-cut valve described above, as shown in FIG.
As indicated by the broken line, after the vibration frequency exceeds the sprung mass resonance range a, the damping force generated by the high cut valve is set to a low value to suppress the force transmitted to the vehicle body.

Therefore, even when the vibration frequency is in the unsprung resonance range b, it is impossible to secure a large force, that is, a high damping force, transmitted to the vehicle body, which is required at this time. It is impossible to prevent the so-called fluttering below, and thus it is not possible to prevent the ground contact property of the wheel with respect to the road surface from being deteriorated and the running stability of the vehicle being impaired.

By the way, a hydraulic shock absorber equipped with a high cut valve is further equipped with a so-called low cut valve,
By setting the low-cut valve to generate a high damping force when the vibration frequency is in the unsprung resonance region b, so-called flapping under the spring can be prevented.

However, in this case, the high cut valve and the low cut valve themselves have a complicated structure, and
There is a disadvantage that the total number of valves to be equipped is increased, resulting in a large increase in manufacturing cost of the hydraulic shock absorber.

Therefore, the force transmitted to the vehicle body for damping the sprung member and the unsprung member, that is, the damping force, is the same as in the conventionally proposed so-called passive hydraulic shock absorber.
It is assumed that the vibration frequency is set to a high value when it is in the sprung resonance region a and the unsprung resonance region b, while the vibration frequency passes through the sprung resonance region a and then the unsprung resonance region b.
In the region c up to, the damping force, that is,
It may be set so as to reduce the force transmitted to the vehicle body.

The force transmitted to the vehicle body is transmitted to the vehicle body side through a piston rod which is a vehicle body side member, and the piston rod slides on a cylinder which is an axle side member and is affected by friction. Since the vehicle is in the state of receiving the force, if the setting is made so as to suppress the influence of the friction on the piston rod, the force transmitted to the vehicle body can be reduced.

The present invention was conceived in view of the above-mentioned circumstances and in view of the above-mentioned points of view, and its purpose is to prevent the spring structure from being unduly complicated. Enables upper and lower spring damping,
It is an object of the present invention to provide a hydraulic shock absorber that is suitable for mounting on a vehicle, which enables improvement of traveling stability in a vehicle and improvement of riding comfort in the vehicle.

[0012]

In order to achieve the above-mentioned object, the basic construction of the present invention is such that a piston rod, which is a vehicle body side member, is inserted and retractable into a cylinder, which is an axle side member. In addition, in a hydraulic shock absorber formed so that a predetermined damping force is generated by a damping valve when a piston portion connected to the piston rod slides in a cylinder, a piezoelectric element for a sensor is provided on the piston rod. And the piezoelectric element for the actuator are connected in series, the sensor weight is connected to the sensor piezoelectric element, and the actuator weight is connected to the actuator piezoelectric element. The output signal is input to the controller, and at the same time, the actuator piezoelectric element is controlled by the command signal selectively output from the controller. Dynamic and actuator weight and is to become formed so as to vibrate.

If necessary, the damping valve is formed so as to allow adjustment of the generated damping force, and the adjustment of the generated damping force in the damping valve outputs a signal to the actuator piezoelectric element. Are formed so as to be executed by the output signal from

[0014]

Therefore, when the piston portion slides in the cylinder, the damping valve causes a predetermined damping force, that is, the sprung mass and the unsprung mass when the vibration frequency is in the sprung mass resonance region and the unsprung mass resonance region. A high damping force is generated for the vibration control of.

When the piston portion slides in the cylinder, that is,
When the piston rod vibrates, the sensor weight vibrates, and the vibration of the sensor weight causes a signal to be output from the sensor piezoelectric element to the controller.

On the other hand, the controller does not output the command signal based on the signal from the sensor piezoelectric element to the actuator piezoelectric element when the vibration frequency is in the sprung resonance region and the unsprung resonance region.

On the other hand, when the vibration frequency is in the region from the sprung resonance region to the unsprung resonance region, the controller commands the actuator piezoelectric element based on the output signal from the sensor piezoelectric element. Output a signal.

The actuator piezoelectric element expands by so-called energization and contracts so as to return to the old state when the energization is released. The expansion and contraction of the actuator piezoelectric element are repeated in a short time, and as a result, the actuator weight vibrates.

By setting the vibration of the actuator weight in the opposite direction to the vibration direction of the piston rod, the vibration of the piston rod is suppressed by so-called cancellation, and to that extent, the cylinder of the piston rod is suppressed. To the vehicle body and therefore the force transmitted by the piston rod to the vehicle body.

As a result, when the vibration frequency is in the region from the sprung resonance region to the unsprung resonance region,
The damping force generated by the damping valve can be apparently lower.

At this time, if the damping valve is constructed so as to be able to adjust the generated damping force, the state of generation of the damping force having a lower value can be achieved.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a hydraulic shock absorber according to an embodiment of the present invention will be described below with reference to the illustrated embodiment. While the piston rod 2 is inserted into and retracted from the shaft sealing structure so that the piston rod 3 is slidably accommodated in the cylinder 1, the piston portion 3 is provided continuously with the tip which is the lower end of the piston rod 2 in the figure. An expansion-side oil chamber R1 and a compression-side oil chamber R2 are formed in the cylinder 1 by partitioning.

The piston portion 3 is provided in the expansion side oil chamber R.
The check valve 4 on the extension side that blocks the flow of the hydraulic oil from 1 toward the pressure side oil chamber R2, and the hydraulic oil from the extension side oil chamber R1 parallel to the check valve 4 toward the pressure side oil chamber R2. Extension side damping valve 5 that generates a predetermined damping force when flowing
And have.

Further, the hydraulic shock absorber comprises an outer cylinder 6 which is arranged on the outer periphery of the cylinder 1 at an appropriate interval,
A reservoir chamber R3 is formed between the outer cylinder 6 and the cylinder 1, and at the same time, a base valve portion 7 accommodated inside the lower end of the cylinder 1 is provided, and a pressure side of the base valve portion 7 is provided. The check chamber 8 and the damping valve 9 on the pressure side enable communication between the reservoir chamber R3 and the oil chamber R2 on the pressure side.

The shaft seal structure has a well-known bearing member 10 and a seal member 11.

In the hydraulic shock absorber, the base end of the piston rod 2 which is the upper end in the drawing is connected to the vehicle body B with the insulator 12 interposed, and the bottom end of the cylinder 1 which is the lower end in the drawing is connected. It is said that it is connected to the axle A via an eye 13 that is continuously provided there.

In this embodiment, the base end portion of the piston rod 2 is composed of the plug 14, and the piston rod 2 is connected to the insulator 12 via the plug 14.

Therefore, according to the hydraulic shock absorber configured as described above, when the piston portion 3 slides in the cylinder 1, the damping valves 4 and 9 are used to provide predetermined damping side and compression side damping, respectively. Force is generated, the damping force at this time,
That is, due to the normal damping force, the vibration on the spring is in the unsprung resonance area b (see FIG. 8) and the vibration frequency is in the unsprung resonance area a (see FIG. 8) when the vibration frequency as the piston speed is in the unsprung resonance area a (see FIG. 8). It becomes possible to control the unsprung vibration.

By the way, in the hydraulic shock absorber, the piston rod 2 has a friction reducing mechanism 20 inside the base end side which is the upper end side in the drawing.

The friction reducing mechanism 20 is provided to reduce the force for controlling the vibration of the vehicle body B, that is, the force transmitted to the vehicle body B by the piston rod 2. In this embodiment, As shown in FIG. 2, a piezoelectric element 21 for a sensor, which is disposed in a chamber 2a formed inside the upper end of the piston rod 2 and is fixedly connected to the piston rod 2, and a piezoelectric element 21 for the sensor. A sensor weight 22 that is integrally connected and a plug 1 that constitutes a piston rod 2.
Actuator piezoelectric element 23 fixedly connected to
And an actuator weight 24 that is integrally connected to the actuator piezoelectric element 23.

Then, a lead wire 21a electrically connected to the sensor piezoelectric element 21 and a lead wire 23a electrically connected to the actuator piezoelectric element 23 are opened at the shaft core of the plug 14, respectively. It is said that it is connected to a controller C, which is so-called externally extended through the through hole 14a and is provided outside the hydraulic shock absorber (see FIG. 1).

The sensor piezoelectric element 21 and the sensor weight 2
2. In this embodiment, the actuator piezoelectric element 23 and the actuator weight 24 are arranged in series so as to coincide with the axial direction of the piston rod 2.

The sensor weight 22 is set to have a smaller mass than the actuator weight 24, and when the piston rod 2 is vibrated, the sensor weight 22 is set to vibrate accordingly. The sensor piezoelectric element 21 is set so as to generate a so-called electromotive force by the vibration of the sensor weight 22.

On the other hand, the actuator weight 24 is set so that its mass can affect the vibration of the piston rod 2 when it vibrates, and the actuator piezoelectric element 23 is so-called energized. It is set so that it expands when it moves, that is, it expands in the axial direction.

Therefore, according to the friction reducing mechanism 20 constructed as described above, when the piston rod 2 is vibrated, the sensor weight 22 vibrates, which causes the sensor piezoelectric element 21 to vibrate. The signal is input to the controller C.

At this time, the controller C selectively outputs a command signal to the actuator piezoelectric element 23, and the command signal is input to the actuator piezoelectric element 23, that is, the current is expanded to expand the command signal. The actuator weight 24 is moved.

When the energization is released, the actuator piezoelectric element 23 contracts so as to return to the old shape, and at this time, the actuator weight 24 moves to the original position.

Therefore, when the command signal from the controller C is a so-called on / off signal, expansion and contraction are repeated in the actuator piezoelectric element 23, and at this time, the actuator weight 24 is moved in the axial direction of the actuator piezoelectric element 23. It will be moved in the axial direction of the barrel piston rod 2.

Further, since the expansion and contraction of the actuator piezoelectric element 23 is realized instantly,
When the command signal from the controller C is a so-called on / off signal in a short time, the movement of the actuator weight 24 is instantaneously realized, that is, the actuator weight 2
4 will vibrate.

As a result, the vibration of the actuator weight 24 is set in the opposite direction to the vibration direction of the piston rod 2, so that the vibration of the piston rod 2 can be suppressed by so-called cancellation. In, the friction of the piston rod 2 with respect to the cylinder 1 can be reduced.

Since the friction of the piston rod 2 with respect to the cylinder 1 is reduced, the force transmitted to the vehicle body B by the piston rod 2, that is, the expansion side and the compression side generated by the damping valves 5 and 9 are described. The damping force will be apparently reduced.

The friction reducing mechanism 20 is provided inside the upper end of the piston rod 2, but instead of this, as shown in FIG. 3, it may be provided outside the upper end of the piston rod 2. good.

Explaining a little, in this embodiment,
The friction reduction mechanism 20 is arranged in a housing 25 that is arranged above the insulator 12 and is connected to the upper end of the piston rod 2, and the piezoelectric element 21 for the sensor and the sensor piezoelectric element 21 are provided in the housing 25. Weight 22,
It is assumed that the actuator piezoelectric element 23 and the actuator weight 24 are housed.

However, in this embodiment, the sensor piezoelectric element 21 and the sensor weight 22 connected to it, the actuator piezoelectric element 23, and the actuator weight 24 connected to it are provided. It is said that they will be placed in a so-called parallel state.

Further, in this embodiment, the actuator piezoelectric element 23 and the actuator weight 24 connected to the actuator piezoelectric element 23 are arranged so that the axis thereof coincides with the axis of the piston rod 2. As the actuator weight 2
Consideration is given so that the vibration of 4 works efficiently.

According to this embodiment, there is an advantage that a large design change such as forming the chamber 2a (see FIG. 2) inside the upper end of the piston rod 2 is not necessary, and the axis line of the friction reducing mechanism 20 is improved. There is an advantage that the total length in the direction can be shortened as compared with the case of the embodiment shown in FIG.

Considering the relationship between the mass of the sensor weight 22 and the mass of the actuator weight 24, the sensor weight 22 and the sensor piezoelectric element 21 are formed in a columnar shape, and the axes thereof correspond to those of the piston rod 2. On the other hand, the actuator weight 24 and the actuator piezoelectric element 23 are formed in a thick cylindrical shape so as to surround the sensor weight 22 and the sensor piezoelectric element 21 from the outer peripheral side. It may be arranged as follows.

By the way, the controller C for controlling the friction reducing mechanism 20 can be freely set as long as a predetermined operation is performed, but in this embodiment, it is configured as follows.

That is, as shown in FIG. 4, the controller C inputs a frequency calculator C1 for inputting a signal from the sensor piezoelectric element 21, and a signal x and a set value y from the frequency calculator C1. The comparator C2, the switch circuit C3 for inputting the signal from the comparator C2 and the signal from the sensor piezoelectric element 21, and the actuator piezoelectric element 23 for inputting the signal from the switch circuit C3.
And an operational amplifier C4 for outputting a command signal to the.

Then, the controller C having the above-described structure operates according to the control flow shown in FIG.

That is, first, the signal from the sensor piezoelectric element 21 is detected (reference numeral F1 in the drawing), and this is converted into the input frequency x from the wheel by the frequency calculator C1 (reference numeral F2 in the drawing). ..

Next, this input frequency x is compared with the set value y (reference numeral F3 in the figure), and if y <x, a signal is output to the switch circuit C3, and if negative, it is used for the sensor. The signal from the piezoelectric element 21 is returned before being detected.

When the switch circuit C3 is turned on (reference symbol F4 in the figure), a new signal is input from the sensor piezoelectric element 21 (reference symbol F5 in the figure), and the operational amplifier C4 is waited for.
Input the signal to.

Predetermined processing is performed by the operational amplifier C4 (reference numeral F6 in the figure), and finally a predetermined command signal is output to the actuator piezoelectric element 23.

Therefore, according to the operation of the controller C based on the above control flow, when the component of the input frequency x with respect to the set value y, that is, the component of the vibration frequency of 4 to 8 Hz is increased, Since the vibration frequency is in the region c (see FIG. 8) from the sprung resonance region to the unsprung resonance region, at this time, a predetermined command signal is output to the actuator piezoelectric element 23. Therefore, the actuator weight 24 vibrates in a predetermined manner.

When the input frequency x component, that is, the vibration frequency component of 4 to 8 Hz is small with respect to the set value y, the vibration frequency is the sprung resonance region a (see FIG. 8) or the unsprung mass. Since it is in the resonance range b (see FIG. 8), at this time, no command signal is output to the actuator piezoelectric element 23, and the actuator weight 24 does not vibrate.

FIG. 6 shows a hydraulic shock absorber according to another embodiment of the present invention. In this embodiment, the expansion side generated by the expansion side damping valve 5 provided in the piston portion 3 is expanded. It is configured so that the damping force of can be adjusted to high or low.

Explaining a little, in this embodiment,
The piston portion 3 is formed with a bypass passage 15 that connects the extension-side oil chamber R1 and the compression-side oil chamber R2 so as to bypass the extension-side damping valve 5, and the adjustment valve 16 is provided in the bypass passage 15. Are provided.

The adjusting valve 16 is formed, for example, so as to change the flow rate of the hydraulic oil in the bypass passage 15. In this embodiment, the adjusting valve 16 is operated by the actuator 17 built in the piston rod 2. Is configured to be activated.

Therefore, for example, when the operation of the actuator 17 does not guarantee the flow rate of the hydraulic oil in the bypass passage 15, that is, in the normal mode in which the flow of the hydraulic oil through the bypass passage 15 is blocked, The damping valve 5 enables generation of a predetermined, ie, high extension side damping force.

Further, when the operation of the actuator 17 secures the flow rate of the hydraulic oil in the bypass passage 15 entirely, that is, in the soft mode in which the hydraulic oil can flow through the bypass passage 15, The extension-side damping force generated by the damping valve 5 can be reduced.

In this embodiment, the actuator 17 is a command signal from the controller C for operating the friction reducing mechanism 20, that is, as shown in FIG.
It is set to be activated by the command signal from the comparator C2.

Further, the controller C in this embodiment
As shown in FIG. 7, the control flow in FIG. 7 compares the control frequency shown in FIG. 5 with the input frequency x and the set value y (reference numeral F3 in the figure), and when y <x is not satisfied. Of the actuator 17 to the normal mode (reference numeral F7 in the figure) and a signal (reference numeral F6 in the figure) which has been subjected to a predetermined process by the arithmetic amplifier C4.
Is set to the soft mode (reference numeral F8 in the figure).

Therefore, according to this embodiment, when the component of the input frequency x with respect to the set value y, that is, the component of the vibration frequency of 4 to 8 Hz becomes large, the vibration frequency becomes the sprung resonance region. Since it will be in the region c from passing through to the unsprung resonance region, at this time, the actuator 1
7 is operated in the soft mode direction, so that the circulation of the hydraulic oil in the bypass passage 15 is secured and the damping force generated in the damping valve 5 is reduced.

When the component of the input frequency x with respect to the set value y, that is, the component of the vibration frequency of 4 to 8 Hz is small, the vibration frequency is in the sprung resonance region a or the unsprung resonance region b. Therefore, at this time, the actuator 17 is operated in the normal mode direction, and accordingly, the flow of the hydraulic oil in the bypass passage 15 is blocked and the damping force generated by the damping valve 5 remains the high damping force. Maintained at.

FIG. 8 shows the state of generation of the damping force when the vibration frequency is in the region c from the sprung resonance region to the unsprung resonance region.
As indicated by the phantom line in the figure, the state of generation of the damping force lower than that in the case of a so-called high-cut valve (broken line portion in the figure), that is, the force transmitted to the vehicle body becomes smaller.

[0067]

As described above, according to the present invention, the force transmitted to the vehicle body for damping the sprung mass and the unsprung mass, that is, the damping force, is achieved in the so-called conventional passive hydraulic shock absorber. Similarly, while the vibration frequency is set to a high value when it is in the sprung resonance region and the unsprung resonance region, the region where the vibration frequency passes from the sprung resonance region to the unsprung resonance region When it is, it is possible to reduce the damping force, that is, the force transmitted to the vehicle body, and there is an advantage that it is possible to improve the riding comfort in the vehicle while ensuring the traveling stability in the vehicle. is there.

Further, according to the present invention, in principle, the structure of the damping valve is not complicated and the number of arrangements is not increased, so that the number of parts is greatly increased and the number of assembling steps is increased accordingly. The advantage is that it does not cause a significant increase in product cost.

Further, according to the present invention, the damping force can be adjusted so that the running stability and the riding comfort of the vehicle can be improved and improved more effectively.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view showing a friction mechanism in the present invention.

FIG. 3 is a partially enlarged sectional view showing a friction mechanism according to another embodiment.

FIG. 4 is a diagram showing a configuration of a controller according to the present invention.

FIG. 5 is a diagram showing a configuration of a control flow in the present invention.

FIG. 6 is a schematic sectional view showing a hydraulic shock absorber according to another embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a control flow according to another embodiment.

FIG. 8 is a damping force characteristic diagram of a conventional passive hydraulic shock absorber.

[Explanation of symbols]

 1 Cylinder 2 Piston Rod 3 Piston Part 5, 9 Damping Valve 21 Sensor Piezoelectric Element 22 Sensor Weight 23 Actuator Piezoelectric Element 24 Actuator Weight C Controller

[Procedure amendment]

[Submission date] May 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art A hydraulic shock absorber mounted on a vehicle is generally formed so as to enable damping of sprung mass and unsprung mass, and the force transmitted to the vehicle body for this damping, that is, The damping force is set to a high value when the vibration frequency is in the sprung resonance region a and the unsprung resonance region b, for example, as shown by the solid line in FIG.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

Therefore, the force transmitted to the vehicle body for damping the sprung mass and the unsprung mass, that is, the damping force, has the same vibration frequency as that of the conventionally proposed so-called passive hydraulic shock absorber. It is assumed that a high value is set when in the upper resonance region a and the unsprung resonance region b, while the vibration frequency is a region from passing through the unsprung resonance region a to reaching the unsprung resonance region b. When it is in c, the damping force,
That is, it may be set so as to reduce the force transmitted to the vehicle body (see the chain double-dashed line portion in FIG. 8).

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

Therefore, according to the hydraulic shock absorber configured as described above, when the piston portion 3 slides in the cylinder 1, each of the predetermined expansion side and compression side damping is provided by the damping valves 5 and 9. A force is generated, and at this time, the damping force, that is, the normal damping force, suppresses the sprung mass when the vibration frequency, which is the piston velocity, is in the sprung mass resonance region a (see FIG. 8), and Unsprung vibration can be suppressed when the vibration frequency is in the unsprung resonance region b (see FIG. 8).

[Procedure correction 4]

[Document name to be amended] Statement

[Item name to be corrected] 0040

[Correction method] Change

[Correction content]

As a result, the vibration of the actuator weight 24 is set in the opposite direction to the vibration direction of the piston rod 2, so that the piston rod 2 is so-called offset.
Vibrations of the cylinder 1, the bearing 10, and the piston rod 2 can be suppressed.
Friction on the seal 11 and the like can be reduced.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

The friction on the cylinder 1, bearing 10, seal 11 and the like in the piston rod 2 is reduced, so that the force transmitted to the vehicle body B by the piston rod 2, that is, the damping valves 5, 9
The damping forces on the extension side and the compression side generated in 1 are apparently reduced.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0057

[Correction method] Change

[Correction content]

FIG. 6 shows another embodiment of the present invention. In this embodiment, the expansion-side damping force and the compression-side generated by the expansion-side damping valve 5 provided in the piston portion 3 are compared. The pressure-side damping force generated by the damping valve 9 of FIG.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction content]

Therefore, for example, when the operation of the actuator 17 does not guarantee the flow rate of the hydraulic oil in the bypass passage 15, that is, in the normal mode in which the flow of the hydraulic oil through the bypass passage 15 is blocked, The damping valve 5 makes it possible to generate a predetermined damping force, that is, a high damping force and a high damping force.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction content]

Further, when the operation of the actuator 17 secures the flow rate of the hydraulic oil in the bypass passage 15 entirely, that is, in the soft mode in which the hydraulic oil can flow through the bypass passage 15, The expansion-side damping force generated by the damping valve 5 and the compression-side damping force generated by the damping valve 9 can be reduced.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction content]

Further, the control flow in the controller C in this embodiment is as shown in FIG.
Compared with the control flow shown in, the input frequency x and the set value y
Is compared (reference numeral F3 in the figure), and when the signal is not y <x, the actuator 17 is set to the normal mode (reference numeral F7 in the figure), and a predetermined process is performed by the arithmetic amplifier C4 ( Actuation of the actuator 17 in the soft mode by the signal F6 in the figure (reference F8 in the figure),
Will be added.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0064

[Correction method] Change

[Correction content]

Therefore, according to this embodiment, the set value y
On the other hand, when the component of the input frequency x, that is, the component of the vibration frequency of 4 to 8 Hz is large, the vibration frequency is a region c from the sprung resonance region a to the unsprung resonance region b. Therefore, at this time, the actuator 17 is operated in the soft mode direction,
Therefore, the circulation of the hydraulic oil in the bypass passage 15 is secured, and the damping force on each side generated by the damping valve 5 and the damping valve 9 is reduced.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0065

[Correction method] Change

[Correction content]

When the component of the input frequency x, that is, the vibration frequency component of 4 to 8 Hz is small with respect to the set value y, the vibration frequency is in the sprung resonance region a or the unsprung resonance region b. Therefore, at this time, the actuator 17 is operated in the normal mode direction, and therefore, the flow of the hydraulic oil in the bypass passage 15 is blocked, and the damping valves 5 and 9 which generate damping on each side. The force remains high damping.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Name of item to be corrected] Brief explanation of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view showing a friction reducing mechanism according to the present invention.

FIG. 3 is a partial enlarged sectional view showing a friction reducing mechanism according to another embodiment.

FIG. 4 is a diagram showing a configuration of a controller according to the present invention.

FIG. 5 is a diagram showing a configuration of a control flow in the present invention.

FIG. 6 is a schematic sectional view showing a hydraulic shock absorber according to another embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a control flow according to another embodiment.

FIG. 8 is a damping force characteristic diagram of a conventional passive hydraulic shock absorber.

[Explanation of symbols] 1 cylinder 2 piston rod 3 piston part 5,9 damping valve 21 piezoelectric element for sensor 22 sensor for 23 piezoelectric element for actuator 24 weight for actuator C controller

[Procedure Amendment 13]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

Claims (2)

[Claims] 1. A piston rod, which is a vehicle body side member, is inserted into a cylinder, which is an axle side member, so as to be retractable, and is damped when a piston portion connected to the piston rod slides in the cylinder. In a hydraulic shock absorber formed so that a predetermined damping force is generated by the valve,
A piezoelectric element for a sensor and a piezoelectric element for an actuator are connected to a piston rod, a weight for a sensor is connected to the piezoelectric element for a sensor, and a weight for an actuator is connected to the piezoelectric element for an actuator, respectively. A signal output from the piezoelectric element for sensor is input to the controller due to the vibration, and the piezoelectric element for actuator is activated by the command signal selectively output from the controller, and the weight for actuator is formed to vibrate. Hydraulic shock absorber characterized by 2. The damping force generated by the damping valve is adjustable, and the generated damping force is adjusted by an output signal from a controller that outputs a signal to the actuator piezoelectric element. The hydraulic shock absorber according to claim 1