JP2001041859A - Initial adjustment of damping force adjusting mechanism, inspection method and damping force test device - Google Patents

Abstract

(57) [Problem] To provide a damping force adjustment type hydraulic shock absorber capable of initial adjustment of a damping force adjustment mechanism based on a constant input. SOLUTION: The damping force adjusting mechanism 3 of the damping force adjusting type hydraulic shock absorber is expanded and contracted and the reservoir ports 14, 15, 16 are respectively connected to the first and second and tank ports 46, 47, 48 of the damping force test device 45. Connect to A pump 56, a flow control valve 55 with a pressure compensating valve, and a flow meter 52 allow a constant flow of the oil liquid to extend and flow between the contraction ports 14 and 15 irrespective of the pressure. Pressure difference with a pressure gauge 66,
Measured by 67. With a constant current applied to the proportional solenoid 36, the adjusting screw 42 is rotated by the adjusting tool 42, and the spool 40 is moved by adjusting the spring force of the return spring 40 to adjust the flow passage area between the ports 29 and 30. Then, the pressure difference between the inlet side and the outlet side of the extension side damping valve 20 is made to coincide with the target value. Thereby, the initial load of the return spring 40 can be adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an initial adjustment method of a damping force adjusting mechanism for adjusting an initial state of a damping force adjusting mechanism of a damping force adjusting hydraulic shock absorber, and a method of inspecting a damping force adjusting mechanism after adjustment. And a damping force test apparatus used for implementing these methods.

[0002]

2. Description of the Related Art For example, a hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile includes a damping force adjusting type hydraulic shock absorber capable of appropriately adjusting a damping force according to a running state of a vehicle, a road surface condition, and the like. There is. In general, a damping force-adjustable hydraulic shock absorber slidably fits a piston connected to a piston rod in a cylinder filled with an oil liquid, and controls the flow of the oil liquid generated by the stroke of the piston accompanying the expansion and contraction of the piston rod. The damping force is generated by controlling with an orifice, a disc valve or the like, and the damping force is adjusted by changing the flow area of the oil liquid by a solenoid control valve or the like.

In such a damping force adjusting type hydraulic shock absorber,
It is necessary to initially adjust the solenoid control valve so that a constant damping force can be obtained for a constant current supplied to the proportional solenoid. Therefore, conventionally, the damping force-adjustable hydraulic shock absorber after the completion of assembly is set in the damping force measuring device, the piston rod is actually expanded and contracted to measure the damping force, and the initial value of the solenoid control valve is determined based on the result. Adjustments were being made.

[0004]

However, the above-mentioned conventional method of initial adjustment of the damping force-adjustable hydraulic shock absorber has the following problems. It takes time and effort to attach the damping force adjustment type hydraulic shock absorber to the damping force measurement device after assembly is completed, and the work efficiency is poor.In addition, the damping force measurement device requires extensive mechanical equipment to actually extend and retract the piston rod This has caused an increase in manufacturing costs. The initial adjustment of the damping force-adjustable hydraulic shock absorber can be performed by adjusting a constant piston speed so that a constant damping force is generated.However, it is not possible to maintain a constant piston speed. It is very difficult because of the restriction of the stroke of the piston rod.

The present invention has been made in view of the above points, and provides a method capable of easily performing initial adjustment and inspection of a damping force adjusting mechanism and a damping force test apparatus for implementing the method. The purpose is to do.

[0006]

According to a first aspect of the present invention, there is provided an initial adjustment method for a damping force adjusting mechanism, comprising: a fluid supply means for supplying a constant flow rate of fluid to the damping force adjusting mechanism; A pressure measuring means for measuring the pressure on the inlet side and the outlet side of the damping force adjusting mechanism is connected, and a constant flow rate of fluid is passed through the damping force adjusting mechanism, and the inlet side and the outlet side of the damping force adjusting mechanism. Is measured, and the damping force adjusting mechanism is adjusted so that the pressure difference matches a predetermined target value.

[0007] With this configuration, a constant flow rate of fluid is supplied to the damping force adjusting mechanism, so that initial adjustment can be performed based on a constant input.

According to a second aspect of the present invention, there is provided an initial adjustment method for the damping force adjusting mechanism according to the first aspect, wherein the damping force adjusting mechanism is a solenoid control valve, and a constant reference current is supplied to the solenoid. The damping force adjusting mechanism is adjusted.

With this configuration, the initial adjustment of the solenoid control valve can be performed based on a constant input.

According to a third aspect of the present invention, in the initial adjustment method of the damping force adjusting mechanism according to the second aspect, the reference current is a current having a sufficiently large damping force change rate with respect to a change in the current of the solenoid control valve. There is a feature.

[0011] With this configuration, the fluctuation of the measured pressure difference with respect to the change of the adjustment position increases, so that the adjustment accuracy can be improved.

According to a fourth aspect of the present invention, there is provided a method for inspecting a damping force adjusting mechanism, comprising: a fluid supply means for supplying a fluid to the damping force adjusting mechanism; and a pressure measuring means for measuring pressures on an inlet side and an outlet side of the damping force adjusting mechanism. When a constant flow rate of fluid is passed through the damping force adjusting mechanism, the damping force of the damping force adjusting mechanism is adjusted from the hard side to a constant reference value, and when the damping force is adjusted from the software side to the reference value. For each, measure the pressure difference between the inlet side and the outlet side of the damping force adjustment mechanism, pass if these pressure differences are within a certain reference range,
If not, it is rejected.

With this configuration, it is possible to easily find a variation in the damping force due to the hysteresis of the damping force adjusting mechanism.

A damping force test apparatus according to a fifth aspect of the present invention provides a damping force adjusting mechanism, a plurality of ports connected to the damping force adjusting mechanism, fluid supply means for supplying a constant flow rate of fluid between the ports regardless of the pressure, and the port And a pressure measuring means for measuring the pressure.

[0015] With this configuration, the damping force adjusting mechanism is connected to the port, a constant flow rate of fluid is supplied between the ports, and the pressure between the inlet side and the outlet side of the damping force adjusting mechanism is measured by the pressure measuring means. By measuring the difference, initial adjustment and inspection of the damping force adjustment mechanism can be performed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The damping force adjusting type hydraulic shock absorber according to the present embodiment will be described with reference to FIG. FIG.
As shown in FIG. 1, the damping force adjusting type hydraulic shock absorber 1 is composed of a substantially cylindrical hydraulic shock absorber main body 2 and a damping force adjusting mechanism 3 attached to the outside (for example, a side surface).

The hydraulic shock absorber main body 2 has a piston 5 slidably fitted in a cylinder 4 filled with an oil liquid.
The inside of the cylinder 4 is moved by the piston 5 to the cylinder upper chamber 4a.
And a lower chamber 4b. Piston 5
Is connected to one end of a piston rod 6, and the other end of the piston rod 6 extends outside the cylinder 4 through the cylinder upper chamber 4a. A reservoir 8 filled with oil and gas is connected to the cylinder lower chamber 4b via a base valve 7 provided at the bottom of the cylinder 4.

The piston 5 has an oil passage 9 communicating between the cylinder upper and lower chambers 4a and 4b, and a cylinder lower chamber 4b of the oil passage 9.
A check valve 10 that allows only the flow of the oil liquid from the side to the cylinder upper chamber 4a side is provided. The base valve 7 has an oil passage 11 for communicating the cylinder lower chamber 4b and the reservoir 8 with each other.
Further, a check valve 12 is provided which allows only the flow of the oil liquid from the reservoir 8 side of the oil passage 11 to the cylinder lower chamber 4b side.

The case 13 of the damping force adjusting mechanism 3 is provided with three ports, an expansion port 14, a contraction port 15, and a reservoir port 16, which are oil passages 17, 18, and 19, respectively.
Are connected to the cylinder upper chamber 4a, the cylinder lower chamber 4b, and the reservoir 8 via The case 13 has an extension port 14
An expansion damping valve 20 that controls the flow of the oil liquid from the compression port 15 to the contraction port 15 to generate a damping force, and a compression damping valve that controls the flow of the oil liquid from the contraction port 15 to the reservoir port 16 to generate a damping force. 21 are provided.

The extension damping valve 20 is composed of a main valve 22 which is a pilot type pressure control valve, a sub-valve 23 which is a pressure control valve, and a spool valve 24 which is a variable flow control valve. The internal pressure is applied to the main valve 22
A pilot chamber 25 acting in the valve closing direction of the valve 22 and a fixed orifice 26 constantly communicating the upstream side of the main valve 22 with the pilot chamber 25 are provided. And the spool valve 24
By changing the flow path area between the ports 29 and 30 provided in the sleeve 27 by the movement of the spool 28 slidably fitted in the sleeve 27, the orifice characteristics (damping force is the square of piston speed) In addition to directly adjusting the internal pressure of the pilot chamber 25, the valve characteristics (the damping force is approximately proportional to the piston speed) of the main valve 22 can be adjusted. The sub-valve 23 is for adding a valve characteristic to optimize a damping force characteristic in a low-speed region of the piston speed, that is, an orifice characteristic region.

The contraction-side damping valve 21 is composed of a main valve 31 which is a pilot-type pressure control valve, and a spool valve 24 shared with the extension-side damping valve 20. Main valve 31
Is provided with a pilot chamber 32 for applying an internal pressure in the valve closing direction of the main valve 31, and a fixed orifice 33 for constantly communicating the upstream side of the main valve 31 with the pilot chamber 32. By moving the spool 28 of the spool valve 24 to change the flow path area between the ports 34 and 35 provided in the sleeve 27, the orifice characteristics are directly adjusted and the internal pressure of the pilot chamber 32 is changed. The valve characteristics of the main valve 31 can be adjusted.

When the spool 28 is moved downward in the drawing, the spool valve 24 which is shared by the extension side and the contraction side damping valves 20 and 21 reduces the flow passage area between the ports 29 and 30 and the port 3
Open the flow area between 4, 35, that is, the extension side damping valve 20
When the damping force of the hard side is adjusted, and the damping force of the compression side damping valve 21 is adjusted to the soft side, and the spool 28 is moved upward in the drawing,
Open the flow area between ports 29 and 30 and open ports 34 and 35
When the flow path area between them is reduced, that is, when the damping force of the extension side damping valve 20 is adjusted to the soft side and the damping force of the contraction side damping valve 21 is adjusted to the hard side, and when the spool 28 is set to an intermediate position between these, Open both ports 29 and 30 and between ports 34 and 35,
That is, the ports and lands are arranged so that the damping forces of the extension side and contraction side damping valves 20 and 21 are both adjusted to the soft side.

The damping force adjusting mechanism 3 is a solenoid control valve. A proportional solenoid 36 is attached to one end of a sleeve 27 of the spool valve 24. The tip of an operating rod 38 connected to the plunger 37 is connected to the spool 28. Is in contact with one end. An adjusting screw 39 is screwed into the other end of the sleeve 27, and a return spring 40 (compression spring) is interposed between the adjusting screw 39 and the other end of the spool. Then, the spool 28 is driven by the proportional solenoid 36 with a thrust corresponding to the supplied current.
Is moved against the spring force of the return spring 40,
The damping force on the extension side and the contraction side can be adjusted simultaneously.

An adjusting hole 41 is formed in the outer wall of the case 13 so as to face the adjusting screw 39, and an adjusting tool 42 (see FIG. 1) is inserted through the adjusting hole in a liquid-tight manner. The initial load of the return spring 40 can be adjusted by rotating the adjustment screw 39 from the outside by fitting into the. Normally, the adjustment hole 41 is closed by screwing a blind plug 43. The spool 28 is provided with a communication passage 44 for communicating the chambers at both ends in the sleeve 27 with each other, so that the spool 28 can move smoothly in the sleeve 27.

Next, the operation of the damping force adjusting type hydraulic shock absorber 1 will be described. During the extension stroke of the piston rod 6,
As the piston 5 moves, the check valve 10 of the piston 5 closes and the hydraulic fluid in the cylinder upper chamber 4a is pressurized, and the oil passage 17, the expansion port 14, the expansion damping valve 20, the contraction port 15, and the oil passage
It flows through 18 to the cylinder lower chamber 4b. Thus, before opening the main valve 22 of the extension damping valve 20 (low-speed region of the piston speed), the orifice characteristic is determined by the flow area between the sub-valve 23, the fixed orifice 26 and the ports 29 and 30 of the spool valve 24. A damping force is generated, and after the main valve 22 is opened (a high-speed range of the piston speed), a damping force having valve characteristics is generated according to the opening degree. It should be noted that the oil liquid corresponding to the piston rod 6 having withdrawn from the cylinder 4 flows from the reservoir 8 into the cylinder lower chamber 4b by opening the check valve 12 of the base valve 7.

During the compression stroke of the piston rod, the check valve 10 of the piston 5 is opened with the movement of the piston 5, and the oil liquid in the cylinder lower chamber 4b passes through the oil passage 9 and the cylinder upper chamber 4a.
Directly flows into the cylinder upper and lower chambers 4a and 4b to have substantially the same pressure.
There is no flow of the oil liquid between the compression port and the compression port 15. On the other hand, when the piston rod 6 enters the cylinder 4, the check valve 12 of the base valve 7 closes, and the oil liquid in the cylinder 4 is pressurized to the extent that the piston rod 6 enters, so that the cylinder lower chamber 4b To oil line 18, contraction port 15, contraction side damping valve
21, reservoir 8 through reservoir port 16 and oil passage 19
Flows to Thereby, the main valve of the compression side damping valve 21
Before opening the valve 31 (low-speed range of the piston speed), a damping force of the orifice characteristic is generated due to the flow area between the fixed orifice 33 and the ports 34 and 35 of the spool valve 24, and after the main valve 31 is opened ( In the high-speed range of the piston speed), a damping force having valve characteristics is generated according to the degree of opening.

The spool 28 of the spool valve 24 is moved by the proportional solenoid 36 in accordance with the supplied current to adjust the flow path area between the ports 29 and 30 on the extension side and the ports 34 and 35 on the contraction side. Directly adjusts the orifice characteristics on the extension side and the contraction side,
The valve opening characteristics (valve characteristics) of the main valves 22 and 31 can be adjusted by changing the internal pressures of the valves 25 and 32. At this time,
When the spool 28 is moved upward in the figure, the extension side is adjusted to the soft side and the contraction side is adjusted to the hard side, and when moved downward, the extension side is adjusted to the hard side and the contraction side is adjusted to the soft side,
In addition, when the intermediate positions are set, both the extension side and the contraction side are adjusted to the soft side.

Next, referring to FIG. 1, the damping force adjusting mechanism 3 will be described.
Force test equipment 45 for initial adjustment and inspection
Will be described. As shown in FIG. 1, the damping force test device 45 includes an extension port 14 and a contraction port 14 of the damping force adjustment mechanism 3.
A first pressure port 46, a second pressure port 47, and a tank port 48, which can be connected to the reservoir port 15 and the reservoir port 16, respectively, are provided. A first pressure port 46 is connected to a stop valve 50, an electromagnetic on-off valve 51, a flow meter 52, a flow control valve
53, a check valve 54, a filter 55 and a pump 56 are connected to an oil tank 57. Tank port 48
58 connects to an oil tank 57 via a stop valve 59, a filter 60 and a water-cooled oil cooler 61. Second
The pressure port 47 is connected to the electromagnetic on-off valve 51 of the line 49 and the flow meter via a stop valve 64 and an electromagnetic switching valve 65 by lines 62 and 63.
52 and between the stop valve 59 and the filter 60 in the line 58. The first and second pressure ports 46 and 47 are provided with pressure gauges 66 and 67 (pressure measuring means), respectively.

The flow meter 52 rotates the fixed capacity piston motor 52a by the flow of the oil liquid in the pipe 49, and converts the rotation into an electric signal by a power storage type rotation sensor, thereby obtaining an accurate flow rate of the pipe 49. Is to be detected.
The flow control valve 53 is a flow control valve with pressure compensation,
Irrespective of the change in pressure caused by the load on the pressure port 46 and the discharge pressure of the pump 56, the flow rate of the pipe 49 can be maintained at a set value. And the pump
The flow control valve 53 and the flow meter 52 constitute a fluid supply means for supplying a constant flow rate of fluid regardless of pressure. The electromagnetic switching valve 65 is a three-port two-position switching valve, and selectively connects the second pressure port 47 to the conduit 62 or 63 by energization. In FIG. 1, reference numeral 68 denotes a relief valve that relieves the discharge pressure of the pump 56 to the oil tank 57 when the discharge pressure reaches a predetermined pressure, and reference numeral 69 controls the flow of cooling water to the oil cooler 61. It is an electromagnetic on-off valve.

Next, a method of initially adjusting the damping force adjusting mechanism 3 using the damping force test device 45 will be described. FIG.
As shown in (1), the first pressure port 46, the second pressure port 47, and the tank port 48 of the damping force test device 45 are connected to the extension port 14, the contraction port 15, and the reservoir port 16 of the damping force adjustment mechanism 3, respectively. Adjustment hole of damping force adjustment mechanism 3
An adjustment tool 42 is hermetically inserted into the 41 in place of the blind plug 43, and its tip is fitted to the adjustment screw 39.

The stop valves 50, 59, 64 and the solenoid on-off valve 51 of the damping force test device 45 are opened, and the second pressure port is connected to the line 63 by the solenoid switching valve 65, and the pump 56 and the flow control valve 53
And the flow meter 52 is operated. As a result, the oil liquid discharged from the pump 56 passes through the pipe 49 and passes through the first pressure port 46.
Flows into the extension port 14 of the damping force adjusting mechanism 3, flows through the extension side damping valve 20 to the contraction port 47, and flows into the second pressure port
Into the oil tank through line 63 and line 58
Return to 57.

By adjusting the flow control valve 53 and monitoring the flow meter 52, the flow rate of the oil liquid between the first and second pressure ports, that is, between the expansion and contraction ports 14 and 15 of the damping force adjusting mechanism 3, is adjusted to a predetermined piston speed. (In the present embodiment, adjustment is made so as to have a constant value corresponding to 0.3 m / s). At this time, the break-in operation is performed several times (the proportional solenoid of the flow rate and damping force adjusting mechanism 3 is used).
After that, the flow rate is fixed at a value equivalent to a predetermined piston speed (0.3 m / s), and the current flow to the proportional solenoid 36 is determined based on the damping force characteristics of the extension side damping valve 20. It is fixed to a predetermined reference current I _R (0.6 A in the present embodiment) determined (described later).

Expanded and contracted by pressure gauges 66 and 67
While monitoring the pressure difference between 4 and 15, the adjusting screw 39 is rotated by the adjusting tool 42 to increase or decrease the spring force of the return spring 40 to move the spool 28, and move the spool 2 to the port 2 of the extension side damping valve 20.
Adjust the flow path area between 9, 30 to expand and contract ports 14,1
Adjust so that the pressure difference between 5 becomes a predetermined target value. At this time, when the adjustment screw 39 is screwed in to reduce the flow path area of the ports 29 and 30 to increase the pressure difference, first, the adjustment tool 42 is rotated at a somewhat high speed. (For example, if the target pressure specification is 28 to 30 kgf / cm ² , the adjustment is performed at a high speed to 26 kgf / cm ² , and then the adjustment is performed at a low speed to 27.5 kgf / cm ² ). After that, the adjusting tool 42 is rotated at intervals of several degrees, and a running-in operation and a pressure check are performed each time, and the adjustment is repeatedly performed so that the target value is obtained (for example, the pressure difference is reduced to 27 kgf / cm ²⁾ . After that, the adjustment tool 42 is rotated at 5 ° intervals, and each time, a break-in operation is performed several times to check the pressure, and this is repeated several times, and when the pressure is within the target value standard, the adjustment is performed. To end).

In the above adjustment, the reference of the adjustment position of the spool 28, that is, the reference current I _R supplied to the proportional solenoid 36 is determined by the displacement amount of the spool 28 based on the damping force characteristic of the extension damping force adjustment valve 20. The change rate of the damping force (the gradient of the damping force characteristic curve) with respect to the (current supplied) is set to be sufficiently large. As a result, the change in the damping force (pressure of the oil liquid) with respect to the displacement of the spool 28 increases, and the adjustment accuracy can be improved. FIG. 3 shows the current flowing through the proportional solenoid 36 and the pressure difference between the expansion and contraction ports 14 and 15 (the expansion-side damping valve) at an oil liquid flow rate equivalent to a piston speed of 0.3 m / s.
20 damping force) (see curve) and shrinkage port
15 shows the relationship (see the curve) with the pressure difference between the reservoir ports 16 (the damping force of the compression side damping valve 21). In this case, the current
In the vicinity of 0.6 A, the change rate of the pressure difference between the elongation side (slope of the curve) is increased, and sets the reference current I _R of the current supplied to the proportional solenoid 36 to 0.6 A. Meanwhile, the current
In the range of 0.3A to 0.4A, there is almost no change in pressure difference.
It is difficult to measure the change in the pressure difference, and the adjustment result tends to vary. Further, it is possible to enhance the adjustment accuracy by also managing the tolerance of the peak value P ₁ of the pressure difference in the current 0.3 A.

As described above, the position of the adjusting screw 39, that is, the initial load of the return spring 40 can be adjusted based on the pressure difference of the oil liquid by the extension-side damping valve 20. At this time, the damping force adjusting mechanism 3 is controlled by the damping force test device 45.
The initial flow rate of the return spring 40 of the spool valve 24 can be adjusted under a constant input corresponding to a constant piston speed, so that the damping force adjusting mechanism 3 is controlled. Can be easily adjusted. This makes it possible to perform the initial adjustment of the damping force adjusting type hydraulic shock absorber without actually expanding and contracting the piston rod 6. The characteristics of the compression-side damping valve 21 are determined by the arrangement of the groove and the land of the spool 28,
There is no need to adjust separately. Further, after adjusting the initial load of the return spring 40, the current flowing to the proportional solenoid 36 and the flow rate of the oil liquid are changed, and the pressure difference between the ports is measured, whereby the damping force of the damping force adjusting mechanism 3 alone is reduced. You can also check the force characteristics.

Further, the electromagnetic switching valve 65 is switched so that the second pressure port 47 communicates with the conduit 62, and the expansion and contraction ports
By pressurizing 14 and 15, the oil liquid flows from the contraction port 15 to the reservoir port 16 through the contraction side damping valve 21, and a pressure difference between the contraction port 15 and the reservoir port 16 (the pressure difference between the reservoir port 16 and the By measuring the pressure (equal to the atmospheric pressure), the initial adjustment of the damping force adjusting mechanism 3 can be performed based on the contraction-side damping valve 21 in the same manner as described above.

Next, a method of inspecting the damping force characteristics of the damping force adjusting mechanism 3 using the damping force test device 45 will be described. As shown in FIG. 4, the damping force adjusting mechanism 3 controls the spool when the current supplied to the proportional solenoid 36 is increased from 0.3 A to 1.3 A and when the current is decreased from 1.3 A to 0.3 A.
A slightly different pressure difference (damping force) is generated for the same current value depending on the movement direction of 28. Extension damping valve 20 and contraction damping valve when current is increased from 0.3 A to 1.3 A
The pressure difference due to 21 is shown by curve A ₁ and curve B ₁ respectively,
The pressure difference caused by the elongation side damping valve 20 and the compression-side damping valve 21 when reduced to 0.3A from 1.3A respectively shown by curves A ₂ and curve B _2. This is caused by variation in thrust due to the displacement direction of the plunger 37 due to the hysteresis of the proportional solenoid 36, sliding friction of the spool 28, and the like. In order to increase the damping force adjustment accuracy of the damping force adjustable hydraulic shock absorber 1, Therefore, it is necessary to manage the hysteresis of the damping force as described above.

Then, by using the damping force test device 45, a specified flow rate (a flow rate corresponding to a piston speed of 0.3 m / s in the present embodiment) and a current (a 0.6A expansion side and a compression side in the present embodiment).
1.0A), the change amounts C ₁ and C ₂ of the pressure difference between the expansion side and the contraction side due to the hysteresis of the damping force adjustment mechanism 3 are actually measured, and these changes C ₁ and C ₂ are calculated by the damping force adjustment type. Hydraulic shock absorber 1
Pass if it is within a certain reference range determined based on the allowable range of the variation of the damping force due to the hysteresis, and fail if it is not. Further, the values of the pressure differences P ₁ and P ₃ at currents of 0.3 A and 1.3 A corresponding to the damping force of the damping force adjusting type hydraulic shock absorber 1 on the extension side and the contraction side at the time of hardware, respectively. It is checked whether or not the values of the pressure differences P ₂ and P ₄ when the current is 0.8 A corresponding to the damping force at the time of softening on both the contraction side are within a predetermined reference pressure range. In this way,
The damping force adjustment mechanism 3 alone can determine whether the tolerance of the damping force characteristic is appropriate.

In the above embodiment, the case 1 is opposed to the ports 46, 47 and 48 of the damping force test device 45.
3. One damping force adjusting mechanism 3 (assembly) including the extension side damping valve 20, the contraction side damping valve 21, the proportional solenoid 36, and the like.
Each of the ports 46, 47 of the damping force test device 45 is shown as being connected one by one and inserting the adjusting tool 42 into the adjusting hole 41 instead of the blind plug 43 for initial adjustment. A case (corresponding to the case 13) dedicated to the initial adjustment, in which the adjustment tool 42 is provided, is connected in advance in opposition to the cases 48 and 48. The sub-assembly of the damping force adjusting mechanism composed of 36 or the like may be inserted into a case dedicated to the initial adjustment to perform the initial adjustment. In this case, the trouble of inserting the adjusting tool 42 instead of the blind plug 43 one by one can be omitted,
There is no need to form the adjustment hole 41 in the product case,
Manufacturing costs can be significantly reduced.

In the above embodiment, the initial adjustment method of the solenoid-controlled spool valve is described as an example. However, the present invention is not limited to this, and other types of valves (manual adjustment-type valves) may be used. The same can be applied to the initial adjustment (including the adjustment), and the damping force generating mechanism without the adjusting mechanism can be calibrated under a constant input using the damping force test device.

[0041]

As described above in detail, according to the initial adjustment method of the damping force adjusting mechanism of the first aspect, by supplying a constant flow rate of fluid to the damping force adjusting mechanism, it is easy to control the damping force adjusting mechanism based on a constant input. The initial adjustment of the damping force-adjustable hydraulic shock absorber can be performed without actually expanding and contracting the piston rod.

According to the initial adjustment method of the damping force adjusting mechanism according to the second aspect, the adjustment is performed while a constant reference current is supplied to the solenoid control valve, so that the initial control of the solenoid control valve is performed based on a constant input. Adjustments can be made.

According to the initial adjustment method of the damping force adjusting mechanism according to the third aspect, by setting the reference current to a current having a sufficiently large rate of change of the damping force with respect to the change of the current, the measured pressure difference with respect to the change of the adjustment position is obtained. Since the fluctuation increases, the adjustment accuracy can be improved.

According to the inspection method of the damping force adjusting mechanism according to the fourth aspect, it is possible to easily find the variation in the damping force due to the hysteresis of the damping force adjusting mechanism.

According to the fifth aspect of the present invention, the damping force adjusting mechanism is connected to the port, a constant flow rate of fluid is supplied between the ports, and the inlet of the damping force adjusting mechanism is supplied by the pressure measuring means. The initial adjustment and inspection of the damping force adjustment mechanism can be performed by measuring the pressure difference between the side and the outlet side.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state in which a damping force adjustment mechanism of FIG. 2 is connected in a damping force test device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a main body of a damping force adjusting hydraulic shock absorber according to an embodiment of the present invention and a longitudinal section of a damping force adjusting mechanism.

FIG. 3 is a diagram showing a relationship between an energizing current and a pressure difference between ports at a constant flow rate of the damping force adjusting mechanism of FIGS. 1 and 2;

FIG. 4 is a diagram showing a hysteresis of a relationship between an energizing current and a pressure difference between ports at a constant flow rate of the damping force adjusting mechanism of FIGS. 1 and 2;

[Explanation of symbols]

 3 Damping force adjustment mechanism 46 First pressure port 47 Second pressure port 48 Tank port 52 Flow meter (fluid supply means) 53 Flow control valve (fluid supply means) 56 Pump (fluid supply means) 66,67 Pressure gauge

Claims (5)

[Claims] 1. A damping force adjusting mechanism, comprising: a fluid supply means for supplying a constant flow rate of fluid; and a pressure measuring means for measuring pressures on an inlet side and an outlet side of the damping force adjusting mechanism. And a pressure difference between the inlet side and the outlet side of the damping force adjusting mechanism is measured, and the damping force adjusting mechanism is adjusted so that the pressure difference matches a predetermined target value. An initial adjustment method for a damping force adjustment mechanism, characterized in that: 2. The damping device according to claim 1, wherein the damping force adjusting mechanism is a solenoid control valve, and adjusts the damping force adjusting mechanism in a state where a constant reference current is supplied to the solenoid. Initial adjustment method of force adjustment mechanism. 3. The initial adjustment method for a damping force adjusting mechanism according to claim 2, wherein the reference current is a current having a sufficiently large change rate of a damping force with respect to a change in the current of the solenoid control valve. 4. A damping force adjusting mechanism is connected to a fluid supply means for supplying a fluid and pressure measuring means for measuring pressures on an inlet side and an outlet side of the damping force adjusting mechanism. When the fluid is circulated, the damping force of the damping force adjusting mechanism is adjusted to a constant reference value from the hard side and the case where the damping force is adjusted to the reference value from the soft side, respectively, with the inlet side of the damping force adjusting mechanism. A method for inspecting a damping force adjusting mechanism, comprising: measuring a pressure difference from an outlet side; if these pressure differences are within a certain reference range, pass or fail. 5. A plurality of ports connected to a damping force adjusting mechanism, fluid supply means for supplying a constant flow rate of fluid between the ports irrespective of the pressure, and pressure measuring means for measuring the pressure of the ports. A damping force test device, comprising: