JPH0510535B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a variable damping force hydraulic shock absorber capable of adjusting damping force.

Prior Art In this type of hydraulic shock absorber, it is necessary to reliably obtain the desired damping force, so it is necessary to ensure that the rotation of the damping force adjustment adjuster stops at the desired damping force setting position. be. In view of this need, the present applicant has recently proposed a hydraulic shock absorber that is capable of stopping the rotation of the adjuster at a desired damping force setting position, even with a simple configuration (for example, , Patent Application No. 175082 (1982).

Therefore, the outline of the hydraulic shock absorber proposed by the present applicant will be explained below based on FIGS. 1 to 3.

Fig. 1 is a partially cutaway sectional view showing an example of a hydraulic shock absorber proposed by the applicant, Fig. 2 is a sectional view of essential parts showing the vicinity of the stopper mechanism, and Fig. 3 is a line taken along the - line in Fig. 1. FIG.

In FIG. 1, 1 is a cylinder filled with hydraulic fluid, and this interior is formed inside an outer cylinder 2 that surrounds the outer periphery of the cylinder 1 at the bottom (not shown) of the cylinder 1. It communicates with a reservoir chamber 3 for hydraulic fluid. Reference numeral 4 denotes a cylindrical piston rod that sealingly penetrates approximately the center of the guide member 5 provided at one end 1a of the cylinder 1 and protrudes to the outside. A motor 7 and a deceleration mechanism 8 that decelerates and transmits the rotation of the motor 7 to an adjuster 6 for adjusting damping force are respectively housed. This speed reduction mechanism 8 includes a drive gear 7 integrally fixed to a drive shaft 7a driven by a motor 7.
b and a driven shaft 6a with one end connected to the adjuster 6 side.
It is provided between the driven gear 6b and the driven gear 6b fixed to the other end. This speed reduction mechanism 8 consists of gears 8b and 8c supported by a rotating shaft 8a, which mesh with a driving gear 7b and a driven gear 6b, respectively.
The rotation of the motor 7 is decelerated and transmitted to the adjuster 6.
A swinging rod 9 is fixed to the driven shaft 6a. On the other hand, the gear case 12 press-fitted into the piston rod 4 has stopper pins 10 and 11.
are planted at predetermined intervals in the circumferential direction. The swinging rod 9 and the stopper pins 10 and 11 constitute a stopper mechanism 13.

On the other hand, 14 and 15 are used to elastically prevent the swinging rod 9 from rotating before the swinging rod 9 collides with the stopper pins 10 and 11. An elastic body disposed between the two is fixed to the stopper pins 10 and 11 side. Reference numeral 16 denotes a motor control that detects an overload current state of the motor 7 that occurs when the swinging rod 9 contacts the stopper pins 10, 11 via the elastic bodies 14, 15, and brakes the rotation of the motor 7. 17 is a damping force setting device for setting a desired damping force, and is connected to a motor drive circuit 18.

Next, 19 is a cylinder 1 for separating the inside of the cylinder 1 into upper and lower liquid chambers 20 and 21.
The piston 19 is slidably inserted into the piston 19, and the piston 19 has through holes 22, 2 passing through the upper and lower surfaces.
The upper and lower liquid chambers 2 pass through the through holes 22 and 23, covering one side of each of the upper and lower liquid chambers 2, respectively.
Damping force generating means 26 and 27 are provided, which are comprised of plate valves 24 and 25, which create a flow resistance in the hydraulic fluid displacing and flowing between 0 and 21. Further, 28 is a cylindrical stud that integrally connects the piston rod 4 and the piston 19, and a shaft hole 29 that communicates with the lower liquid chamber 21 is formed in the center of the stud. Two orifices 30 and 31 having a predetermined opening diameter are bored in the wall portion at a predetermined interval in the axial direction. These orifices 30 and 31 communicate with the upper liquid chamber 20 through an annular groove 32 provided on the outer periphery of the cylindrical wall portion and a communication hole 33 provided in the cylindrical portion of the piston rod 4, respectively. .

An adjuster 6 rotated by the motor 7 is rotatably accommodated inside the cylindrical wall portion of the stud 28 . This regulator 6 is formed with an axial hole 34 that opens toward the lower liquid chamber 21, and this axial hole 34 and the stud 2
Upper and lower communication holes 35 and 36 are formed to selectively communicate with the eight orifices 30 and 31, respectively. A coil spring 37 is disposed between the adjuster 6 and the stud 28, and elastically biases the adjuster 6 toward the seal member 38.

A cylindrical member 39 is inserted and fixed inside the axial hole 34 formed in the adjuster 6, and its cylindrical wall is connected to each communication hole 3 provided in the adjuster 6.
5 and 36, it is inserted in a position that covers only the lower communication hole 36. The cylindrical wall is provided with a through hole 40 that communicates only with the lower communicating hole 36 of the respective communicating holes 35, 36. A check valve 43 composed of a check spring 41 and a check plate 42 is provided at the upper open end of the cylindrical member 39, and the open end is closed during the extension process of the piston rod 4. However, during the pressure process, the communication hole 3 is opened.
3. The working fluid is selectively allowed to flow between the upper and lower fluid chambers 20 and 21 through the orifice 30 and the communication hole 35.

The stop member 44 provided on the outer periphery of the piston rod 4 is for stopping the upward movement of the piston rod 4 by coming into contact with the lower end surface of the guide member 5, and also serves to stop the upward movement of the piston rod 4. A lubricating plate 45 interposed therebetween is for smooth rotation of the adjuster 6.

Next, the operation of the hydraulic shock absorber having the above configuration will be explained.

First, the orifice 3 formed in the stud 28
A case will be explained in which the points 0 and 31 are closed by the regulator 6.

That is, under such circumstances, the piston 19
When the piston rod 4 moves up inside the cylinder 1, the pressure in the upper liquid chamber 20 becomes high and, conversely, the pressure in the lower liquid chamber 21 becomes low, depending on the piston speed. , the plate valve 24 provided at the outlet end of the through hole 22 constituting the damping force generating means 26 provided in the piston 19 is pushed open according to the magnitude of the pressure to form an orifice, and the orifice is operated at high speed. When passing through the liquid, the static pressure is changed to dynamic pressure, the pressure drops, and the liquid flows into the lower liquid chamber 21. Thus, the upper and lower liquid chambers 20, 21
The piston 19 is urged downward by the pressure difference between the two, and at this time, an extension-side damping force is generated that attempts to prevent the extension stroke.

On the other hand, when the piston rod 4 accompanied by the piston rod 19 descends inside the cylinder 1, the pressure in the lower liquid chamber 21 becomes high, contrary to the case of the above-mentioned extension stroke.
Conversely, since the pressure in the upper liquid chamber 20 is low, the high-pressure hydraulic fluid in the lower liquid chamber 21 passes through the through hole 23 that constitutes the damping force generating means 27 provided in the piston 19, and passes through the through hole 23 provided at the outlet end thereof. The plate valve 25 is pushed open to form an orifice, and when passing through the orifice at high speed, the static pressure is changed to dynamic pressure, the pressure drops, and the liquid flows into the upper liquid chamber 20. Thus, due to the pressure difference between the upper and lower liquid chambers 20 and 21, the piston 19
is urged upward, and at this time, a compression side damping force is generated that attempts to prevent the compression stroke.

As described above, when the orifices 30 and 31 are closed, high damping force can be obtained by allowing the hydraulic fluid to flow only through the damping force generating means 26 and 27 provided on the piston 19.

Next, the orifice 3 formed in the stud 28
0, 31 are communication holes 35 formed in the adjuster 6,
36 will be explained.

That is, when the piston rod 4 moves upward together with the piston 19 under such circumstances, the pressure inside the upper liquid chamber 20 becomes high and the pressure inside the lower liquid chamber 21 becomes low compared to that, so the check plate 42 moves downward. Then, the upper end opening of the cylindrical member 39 is closed. Therefore, when the piston speed is low, the hydraulic fluid in the upper fluid chamber 20 flows from the communication hole 33 of the piston rod 4 to the orifice 31 and the adjustment hole 6.
and the through hole 40 of the cylindrical member 39 in sequence. When passing through the orifice 31, a pressure drop occurs, and the liquid passes through the cylindrical member 39 and the through hole 29 of the stud 28, and then passes through the lower liquid chamber 2.
1. As the piston speed increases further, the pressure within the upper liquid chamber 20 increases. As this pressure increases, a portion of the hydraulic fluid pushes the plate valve 24 further open, causing the lower fluid chamber 2 to open.
1.

Next, when the piston rod 4 moves downward together with the piston 19, the pressure inside the lower liquid chamber 21 becomes high and the pressure inside the upper liquid chamber 20 becomes low compared to that.
Check plate 42 is connected to check spring 41
The upper open end of the cylindrical member 39 is opened by rising against the spring force. Therefore, when the speed of the piston 4 is low, the hydraulic fluid in the lower fluid chamber 21 flows from the inside of the cylindrical member 39 to the through hole 4 formed therein.
0, the liquid flows into the upper liquid chamber 20 through the communication hole 33 through two passages: one passing sequentially through the communication hole 36 and the orifice 31, and the other passing sequentially through the communication hole 35 and the orifice 30. The pressure drop is small because the flow path area is increased compared to when moving upward in step 4. As the piston speed further increases, the pressure within the lower liquid chamber 21 increases. As this pressure increases, a portion of the working fluid pushes the plate valve 24 further open and flows into the lower fluid chamber 21. As described above, when the orifices 30 and 31 are aligned with the communication holes 35 and 36, the hydraulic fluid passes through these orifices 30 and/or 31 when the piston speed is small, and when the piston speed increases, Furthermore, piston 1
By also passing through the damping force generating means 26, 27 provided in the liquid chambers 9, the pressure difference between the upper and lower liquid chambers 20, 21 is made smaller than when the orifices 30, 31 are closed, and a lower damping force can be obtained. .

Next, set the damping force to "low" using the damping force setting device 17.
Or, the case where it is set to "High" will be explained.

First, when the damping force setter 17 is operated and set to "low", the motor drive circuit 18 sends a drive current to the motor 7 based on the signal from the damping force setter 17, and the motor 7 rotates. As the motor 7 rotates, the driving gear 7b and gears 8b and 8c rotate, thereby causing the driven gear 6b and the swinging rod 9 fixed to the gear 6b to move as shown in FIG. Rotate counterclockwise. Thereafter, the swinging rod 9 comes into contact with the elastic body 14 and compresses it. Therefore, rotational resistance increases and overload current flows through the motor 7. This overload current is detected by the motor control section 16, and a stop signal is sent to the motor drive circuit 18, so that the motor 7 is stopped. As a result, regulator 6
As shown in FIG. 3, the communication holes 35, 36
It will stop at the position where it coincides with the orifices 30 and 31. Therefore, a low damping force can be obtained.

Next, when the damping force setter 17 is set to "high", the motor 7 rotates in the opposite direction to "low", and the swinging rod 9 rotates clockwise in FIG. The overload current flows through the motor 7 in order to bias the elastic body 15 with the swing rod 9, as in the "low" case, and this is detected by the motor control unit 16 and sent to the motor drive circuit 18. A stop signal is sent to stop the motor 7. At this time, orifice 30,3
1 is closed by the side wall of the regulator 6. Therefore, a high damping force can be obtained.

By the way, in the case of the above-mentioned hydraulic shock absorber, the swinging rod 9 that rotates as the motor 7 rotates comes into contact with the elastic body 14, and a rotational resistance force of more than a predetermined value is generated in the motor 7. , When an overload current flows through the motor 7, the motor 7 is stopped based on the overload current, so each time the damping force is switched and set,
An abnormal load will be applied to the motor 7, which is not preferable for long-term use of the motor 7. Also,
When the swinging rod 9 comes into contact with the elastic body 14, an abnormal load is applied to each meshing portion of the drive gear 7b and the driven gear 6b with respect to the reduction mechanism 8, and similarly, each gear 7b, 6b and the reduction mechanism 8 undesirable for long-term use.

Purpose of the Invention The present invention has been made in view of these conventional drawbacks, and provides a variable damping force hydraulic shock absorber capable of improving the durability of the motor and reduction mechanism housed in the piston rod. The purpose is to obtain a vessel.

Structure of the Invention In order to achieve such an object, the present invention has the following features:
One of the gears for decelerating and transmitting the rotation of a drive gear driven by a motor provided in the piston rod to the adjuster, which is connected to the driven shaft connected to the adjuster side for adjusting the damping force, The gear is slidably and rotatably attached to a rotating shaft that supports the gear, and a support base is integrally attached to the rotating shaft, and a friction member is provided between the support base and the gear. An elastic body is provided to bias the gear toward the support base via a friction member, and the driven gear stops rotation of the adjuster at a desired damping force setting position. The configuration includes a stopper mechanism that allows the

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. Components that are the same as those of the conventional example are given the same reference numerals, and redundant explanation thereof will be omitted.

FIG. 4 is an enlarged sectional view of essential parts showing an embodiment of a variable damping force type hydraulic shock absorber according to the present invention, and FIG.
It is a sectional view taken along the - line in the figure.

As shown in FIG. 4, with respect to a rotating shaft 8a whose both ends are rotatably supported by end plates 61 and 62,
A first gear 51 having a larger diameter than the drive gear 7b is slidably and rotatably inserted into the support base 52.
and a second gear 8c are integrally fixed to the shaft 8a,
An annular washer 53 made of fluorine resin and having a low coefficient of friction is interposed between the support base 52 and the first gear 51 to elastically bias the first gear 51 toward the support base 52. The compression coil spring 54 is an elastic body that
The speed reduction mechanism 8 is constructed by providing the following. The first gear 51 constituting this reduction mechanism 8 is a drive gear 7 that is rotationally driven together with the motor 7.
b, and the second gear 8c meshes with a driven gear 6b having a larger diameter than the second gear 8c, and transmits the rotation of the motor 7 at a reduced speed to the adjuster 6 via the driven shaft 6a. It's becoming like that. A swinging rod 9 that rotates together with the driven shaft 6a is integrally extended in the radial direction of the driven shaft 6a. The tip of this swinging rod 9 is connected to a notch 5 formed in a fan shape in a rotation regulating plate 56 fixed to the gear case 12.
The sliding rod 9 rotates within the notch 57 and comes into contact with one end of the portion 57 to stop the driven shaft 6a. A stopper mechanism 55 is constituted by the cutout portion 57. Note that 60 is the drive shaft 7a of the motor 7.
63 is a bearing plate that rotatably supports the driven shaft 6a;
4 is fixed to the rotating shaft 8a, and a compression coil spring 54
An annular plate 65 receives one end of the compression coil spring 5
4 and the first gear 51.

Next, the operation of the hydraulic shock absorber according to the present invention having the above configuration will be explained.

First, when the motor 7 is rotationally driven to rotate the drive gear 7b in a predetermined direction, the first gear 51, which is rotatably attached to the rotating shaft 8a, is rotated by the spring force of the compression coil spring 54, causing the washer 53 to rotate. Since the motor 7 is strongly urged toward the support stand 52 through the motor 7, the motor 7 rotates integrally with the support stand 52 due to frictional force, so that the rotation of the motor 7 is decelerated by the first gear 51. is transmitted to the rotating shaft 8a, is further decelerated between the second gear 8c, which is integrally fixed to the rotating shaft 8a, and the driven gear 6b, is transmitted to the driven shaft 6a, and is fixed to the shaft 6a. The swing rod 9 and adjuster 6 are rotated in a predetermined direction. Thereafter, when the swinging rod 9 comes into contact with one side wall in the notch 57 formed in the rotation regulating plate 56, the driven shaft 6a
stops at that contact position. At this time, a slip occurs between the first gear 51 and the support base 52, and the first gear 51 rotates from the rotation axis 8a. Therefore, the rotation of the first gear 51 is no longer transmitted to the driven shaft 6a side, and the adjuster 6 remains stopped at its abutting position.
A desired damping force can be obtained. Note that the power supply to the motor 7 is stopped upon detecting a change in the load current when a slip occurs between the first gear 51 and the support base 52.

As described above, in this embodiment, the first gear 51 and the support base 52 rotate integrally via the washer 53 due to the spring force of the compression coil spring 54, so that the rotation of the motor 7 is controlled by the driven force. It is possible to reliably transmit the signal to the shaft 6a and rotate the adjuster 6. On the other hand, when the swinging rod 9 fixed to the driven shaft 6a comes into contact with one end of the notch 57, Since the first gear 51 slips between the support base 52 and the first gear 51 and rotates idly with respect to the rotating shaft 8a, it is possible to prevent an abnormal load from being applied to the motor 7. Therefore, the durability of the motor 7 can be improved.

Next, FIG. 6 is a sectional view of a main part showing another embodiment of the present invention, which differs from the previous embodiment in the following points.
A small diameter portion is formed at one end of the driven shaft 6a, into which a third gear 58a is rotatably fitted, and a fourth gear 58b is integrally connected to the third gear 58a.
is fixedly installed to mesh with the second gear 8c, which has a smaller diameter than the fourth gear 58b, while a fifth gear 59a is rotatably inserted into a fixed shaft 68 whose both ends are fixed to the gear case 12. A sixth gear 59b is fixed integrally with the fifth gear 59a to mesh with the third gear having a smaller diameter than the fifth gear 59a, and the driven gear 6b has a larger diameter than the sixth gear 59b. This is because they have an interlocking configuration.

Even with this configuration, in addition to obtaining the same functions and effects as in the embodiment described above, it is also possible to obtain the effect that the rotation of the motor 7 can be transmitted to the adjuster 6 at a further reduced speed.

Effects of the Invention As is clear from the above description, the present invention provides a mechanism in which there is a In the variable damping force hydraulic shock absorber, the damping force variable hydraulic shock absorber is provided with a speed reduction mechanism having at least one gear that reduces and transmits the rotation of the driving gear to the driven gear on the adjuster side. is slidably and rotatably attached to a rotary shaft that supports the rotary shaft, and a support base is integrally attached to the rotary shaft, and a washer is interposed between the support base and the gear. , an elastic body is provided to elastically urge the gear to the support base via the washer, and a stopper mechanism is provided on the driven gear side to stop the rotation of the adjuster at a desired damping force setting position. Since the first gear and the support base are rotated together through the washer by the spring force of the elastic body, the rotation of the motor can be reliably transmitted to the adjuster on the driven shaft side. On the other hand, when the adjuster rotates to the desired deceleration force setting position, the stopper mechanism stops the adjuster at that position, so the gear rotates while slipping against the support base, and the motor and drive It is possible to prevent abnormal loads from being applied to gears, driven gears, speed reduction mechanisms, etc. Therefore, the durability of these motors, speed reduction mechanisms, etc. can be improved.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing a conventional variable damping force type hydraulic shock absorber, Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is a sectional view taken along the - line in Fig. 1, and Fig. 4 is a sectional view taken along the - line in Fig. 1. FIG. 5 is a cross-sectional view of main parts showing one embodiment of a variable damping force type hydraulic shock absorber according to the present invention, FIG. 5 is a cross-sectional view taken along the - line in FIG. 4, and FIG. FIG. 1... Cylinder, 1a... One end, 4... Piston rod, 6... Adjuster, 6a... Driven gear,
7... Motor, 7b... Drive gear, 8... Reduction mechanism, 8a... Rotating shaft, 8c... Gear (second gear),
51...Gear (first gear), 52...Support stand, 5
3... Washer, 54... Elastic body (compression coil spring), 55... Stopper mechanism.

Claims (1)

[Claims] 1. A drive gear driven by a motor provided inside a piston rod that extends sealingly through one end of a cylinder filled with hydraulic oil, and a driven gear that rotates a damping force adjustment adjuster. In the variable damping force hydraulic shock absorber, the damping force variable hydraulic shock absorber is provided with a deceleration mechanism having at least one gear for decelerating and transmitting the rotation of the drive gear to the driven gear on the adjuster side. one is slidably and rotatably attached to a rotating shaft that supports the gear, and a support is integrally attached to the rotating shaft, and between the support and the gear, An elastic body is provided with a washer interposed therein to urge the gear to the support base through the washer, and an elastic body is provided on the driven gear side so that the rotation of the adjuster can be set to a desired damping force setting position. A variable damping force type hydraulic shock absorber characterized by being equipped with a stopper mechanism that stops the damping force at the stopper mechanism.