JPH0140356Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber, particularly to a hydraulic shock absorber with adjustable damping force.

In a hydraulic shock absorber, when trying to adjust the damping force in three stages of large, medium, and small, for example, when the damping force is adjusted in either the medium or small stage,
When a vehicle equipped with a shock absorber is subjected to sudden start, sudden stop, sudden steering, etc.
The shock absorber must be set so that the damping force increases accordingly.

The present invention was developed in view of these points, and its purpose is to be able to adjust the damping force in at least three stages, and to reduce the damping force when the vehicle is suddenly operated as described above. It is an object of the present invention to provide a hydraulic shock absorber that can be instantly increased in size and that can reliably shorten the damping force switching time.

That is, the hydraulic shock absorber of the present invention includes a piston fitted into the cylinder to define two liquid chambers in the cylinder, one end connected to the piston, and the other end connected to the cylinder. A piston rod protruding outward, a damping force generating valve provided on the piston to communicate the two liquid chambers, and a damping force generating valve provided on the piston rod to communicate the two liquid chambers by bypassing the damping force generating valve. The piston rod comprises a liquid passage formed therein and an adjusting means for adjusting the magnitude of the damping force due to the liquid passage in at least three stages, and the adjusting means is provided so as to be movable in both forward and reverse directions in a predetermined direction of the piston rod. and has a shutter that selects the magnitude of the damping force by moving to at least four different positions in the predetermined direction, and when the shutter is at the beginning and end of its travel stroke, the shutter It is configured to generate the largest damping force compared to when it is in at least two intermediate positions. It is characterized by

Next, a preferred specific example of the hydraulic shock absorber of the present invention will be explained based on the attached drawings.

In the figure, the inner tube 1 as a cylinder is the outer tube 2.
A cap 3 is fixed to one end of the inner cylinder 1 and outer cylinder 2, and a mounting ring 4 for attaching the shock absorber to an axle or the like is integrally connected to the cap 3. There is. A rod guide 5 and a cap 6 are fitted into the other ends of the inner cylinder 1 and the outer cylinder 2, respectively, and a piston rod 7 passes through the guide 5 and the cap 6 and extends upward. A packing 8 is provided in the cap 6 so as to contact the periphery of the rod 7 in a sealing manner, and the packing 8 is pressed against the inner surface of the cap 6 and the outer peripheral surface of the rod 7 by a spring 10 via a retainer 9. ing.

A piston 11 fitted into the inner cylinder 1 is connected to one end of the rod 7 so as to define the chamber 12 of the inner cylinder 1 into two oil chambers 13 and 14. piston 1
1 includes one-way valves 15 and 16 made of disk valves.
Passages 17 and 18 are provided which are opened and closed, respectively. one-way valves 15, 16 and passage 17,
18 constitutes a damping force generating valve. Further, the piston 11 has chambers 13, which branch from the passage 17.
A passageway is provided to keep 14 in constant communication. 19 is a washer, and 20 is a piston ring.

The valve 15 opens when the hydraulic pressure in the chamber 14 becomes larger than a certain value P0 relative to the hydraulic pressure in the chamber 13,
Allows the oil liquid to flow from the chamber 14 to the chamber 13 via the passage 17, and when the value becomes smaller than a certain value PO, the valve closes and prevents the oil liquid from flowing from the chamber 14 to the chamber 13 via the passage 17. do. The valve 16 is configured such that the hydraulic pressure in the chamber 13 is a certain value P1 relative to the hydraulic pressure in the chamber 14.
The valve opens when the value is larger, and the valve closes when the value is smaller.
It performs the opposite action to valve 15.

An annular chamber 2 defined by an inner cylinder 1 and an outer cylinder 2
1 communicates with a chamber 14 through a through hole 22 bored at one end of the inner cylinder 1, and chambers 21, 13, and 14 contain oil, and an inert gas is placed above the chamber 21. Gas is enclosed.

The rod 7 is provided with a through hole 23 extending in the longitudinal direction from the upper end to the lower end of the rod 7.
A connecting rod 24 rotatably extends within the through hole 23 . The rod 7 also has a through hole 23 and a chamber 13.
A radial through hole 25 is provided that communicates with the. Furthermore, a hexagonal cylinder 26 is screwed onto the lower end of the rod 7, and a disk 27 is held at the lower end of the cylinder 26, and a guide 28 is held within the cylinder 26 by the disk 27. ing. Through hole 23,2
5 constitutes a liquid passage.

A shutter 29 is attached to one end of the connecting rod 24 and is rotatably held within the guide 28. As shown in FIGS. 3 to 5, the guide 2
Fixed orifices 30, 31, 32 and 33 of different diameters are bored as ports on the side circumference of the shutter 8, and when the shutter 29 is rotated within the guide 28 through the connecting rod 24, the hole in the shutter 29 is opened. 34
The fixed orifices 30, 31, 32, and 33 are selectively opened and closed via. Fixed orifice 3
0, 31, 32, and 33 are provided on the side circumferential surface of the guide 28 at angular intervals of about 60 degrees, respectively, and the orifices 32 and 33 are arranged at positions that substantially face each other in the radial direction. Orifice 30, 31, 3
The diameters of orifices 2 and 33 decrease in the order of 30, 31, and 32, and the diameters of orifices 32 and 33 are substantially equal. The hole 34 of the shutter 29 is the hole 34 of the shutter 29.
The side peripheral surface of the orifice 9 is extended with a predetermined width, and this width is set to be smaller than the interval between the orifices 30 and 31 and larger than the diameter of the orifice 30, and functions as a movable orifice for the fixed orifice. do. A check valve 35 is pressed against the upper end of the guide 28 by a spring 36. The connecting rod 24, the guide 28, the orifice, the shutter 29, the hole 34, etc. constitute an adjusting means for adjusting the opening degree of the liquid passage.

An O-ring 37 is fitted into the upper end of the rod 7 to prevent leakage of oil from the hole 23, and a holding member 38 is fitted onto the O-ring 27 to prevent the O-ring 37 from coming off. has been done.

At the protruding end of the connecting rod 24 that protrudes upward from the rod 7, there is a motor 39 that can rotate in forward and reverse directions, and a gear 4.
0, 40 and an encoder 41 as a position detector
The output shaft of an actuator 42 comprising: That is, one end of the encoder 41 is connected to the protruding end, and a gear 40 connected to the other end of the encoder 41 and a gear 40 connected to one end of the motor 39 mesh with each other, so that when the motor 39 is driven to rotate, , the connecting rod 24 is rotated via the gears 40, 40 and the encoder 41. A bracket 44 is fixed on the outer peripheral surface of the upper end of the rod 7 by a nut 43, and a casing 45 of the actuator 42 is fixed onto the bracket 44.

The motor 39 is connected to the output side of the microcomputer 48 via a drive circuit 46 and a pulse generation circuit 47.
On the input side, there is a mode select switch 49, a vehicle speed sensor 50, and a throttle position sensor 5.
1. Output terminals of a steering wheel angle sensor 52, a brake operation switch 53, etc. are connected to the microcomputer 48, and an output terminal of an encoder 41 is connected to the microcomputer 48 to form a feedback circuit. Therefore, the motor 39 is controlled by the microcomputer 48, the pulse generation circuit 47, and the drive by input from any one of the mode select switch 49, vehicle speed sensor 50, throttle position sensor 51, steering wheel angle sensor 52, brake operation switch 53, etc. It is driven via circuit 46.

Three holes 54 are provided on the side peripheral surface of the cylinder 26 at equal angular intervals for communicating the chamber 14 with the fixed orifices 30, 31, 32, and 33. The chamber 14 and the chamber 13 are connected to the hole 54, the fixed orifice, the hole 34, the upper hole 55 of the shutter 29, the inner hole 56 of the guide 28, the guide 28 and the check valve 3.
5, the passage 57 between the through hole 23 and the through hole 25
communicated via.

In the hydraulic shock absorber configured as described above, the mode select switch 49 or the vehicle speed sensor 50
When the adjustment speed may be relatively slow, such as when adjusting the damping force by the input of A high frequency pulse is generated, and the motor 39 is driven by the pulse through the drive circuit 46, and the connecting rod 24 and the shutter 29 are driven through the motor 39, gears 40, 40, and encoder 41.
is rotated intermittently and slowly. At this time, since the encoder 41 is configured to detect the rotational position of the hole 34 of the shutter 29, the hole 34 of the shutter 29 changes from the position corresponding to the orifice 30 as shown in FIG. When rotated to a position corresponding to the orifice 31 as shown, the encoder 41 outputs a predetermined signal associated with the orifice 31, which output signal is received by the microcomputer 48 through the feedback circuit for pulse generation. Circuit 47 and drive circuit 46
The rotation of the motor 39 is stopped via the . Since the rotation of the motor 39 and the shutter 29 at this time is relatively slow and intermittent rotation, the shutter 29 is rotated in response to the output signal from the encoder 41 at a position where the hole 34 communicates with the orifice 31. It will be stopped immediately. The above operation is performed to move the hole 34 from the position corresponding to the orifice 31 to the position corresponding to the orifice 30, or from the position corresponding to the orifice 33 or 32 to the orifice 31 or 3.
The same operation is performed when the shutter 29 is rotated by forward and reverse rotation of the motor 39 so as to come to the position corresponding to zero.

On the other hand, the throttle position sensor 51, the handle angle sensor 52, or the brake operation switch 5
3, when the damping force needs to be adjusted at a relatively high speed in order to prevent the vehicle from sinking or rolling, the microcomputer 48 sends a long-cycle pulse to the pulse generation circuit 47.
That is, a pulse is generated that is substantially equivalent to continuously energizing the motor 39, and the pulse causes the motor 39 to rotate substantially continuously at high speed via the drive circuit 46. At this time, the hole 34 of the shutter 29
is located at a position corresponding to orifice 30, for example, as shown in FIG. , 33, which is closer to orifice 30, that is, orifice 32
The computer 48 issues a command signal to rotate the shutter 29 in the direction. This command signal is transmitted to the pulse generation circuit 47 and drive circuit 46 as described above.
The signal is sent to the motor 39 through the motor 39, and the motor 39 is rotated counterclockwise at high speed. The high speed rotation of the motor 39 is transmitted to the shutter 29 in the same manner as described above, and when the hole 34 of the shutter 29 is rotated at high speed counterclockwise to a position corresponding to the orifice 32 as shown in FIG. A predetermined output signal related to the orifice 32 is output to the computer 48, and the rotational drive of the motor 39 is stopped. At a position where the hole 34 completely communicates with the orifice 32, a stopping means such as a stopper (not shown) is arranged to operate, and the inertia of the motor 39 and the shutter 29 due to the high speed rotation of the motor 39 causes the shutter to stop. Even if the shutter 29 attempts to overrun, the shutter 29 is stopped at the communicating position by stopping the driving of the motor 39 in accordance with the output signal from the encoder 41 and operating the stopper. Such an operation is performed when the hole 34 is
Even when the shutter 29 is in the position corresponding to the orifice 33, the motor 39 is rotated clockwise at high speed, and the shutter 29 is rotated to the position corresponding to the orifice 33.
It is executed similarly.

The stopper is composed of a groove that extends a predetermined length in the circumferential direction on the bottom surface of the shutter 29, and a protrusion that integrally projects upward from the disk 27 to engage with the groove. The counterclockwise rotation of the shutter 29 is prevented by the contact between one end of the groove and the projection at the position shown in FIG. 5, and the clockwise rotation of the shutter 29 is prevented when the hole 34 and the orifice 33 are completely communicated In other words, the shutter 29 is rotated 180 degrees clockwise from the position shown in FIG.
The other end of the groove is set to be stopped by coming into contact with the protrusion, and thus the stopper defines the start and end of the rotational stroke of the shutter 29.

The damping force characteristics of the hydraulic shock absorber are as follows:
When the hole 34 is in a position corresponding to the orifice 30, the damping force is the smallest, and when the hole 34 is in the position corresponding to the orifice 32 or 33, the damping force is largest, and when the hole 34 is in the position corresponding to the orifice 31, the damping force is the smallest. , the damping force is set to have an intermediate magnitude. Therefore, in a vehicle in which the hydraulic shock absorber is incorporated, when the driver selects the desired ride comfort for the vertical vibrations applied to the vehicle, the driver operates the mode select switch 49 to control the motor 3.
9 is rotated relatively slowly and intermittently, and the hole 34 of the shutter 29 is located at a position corresponding to the orifice 30 as described above, the damping force of the shock absorber is minimized, a soft riding comfort is achieved, and the hole If the hole 34 is placed at a position corresponding to the orifice 31, the damping force will be of an intermediate magnitude, and a riding comfort between soft and hard will be achieved. A hard ride can be achieved by placing it in the Note that the selection of the ride comfort described above is based on the vehicle speed sensor 50.
This is done automatically according to a predetermined speed.

On the other hand, when the accelerator is suddenly depressed, the steering wheel is turned hard, or the brakes are applied suddenly, the motor 39 is activated at high speed through the throttle position sensor 51, steering wheel angle sensor 52, brake operation switch 53, etc. The shutter is rotated clockwise or counterclockwise and the shutter 2 is automatically
The hole 34 of 9 is connected to the orifice 32 or 3 as described above.
3, the damping force of the shock absorber automatically increases, resulting in a hard ride.

In the above specific example, the four fixed orifices were provided with an angular spacing of substantially 60°, but the angular spacing between them may be smaller, or even larger in some cases. The position of the encoder and stopper and the width of the shutter hole may be changed according to the requirements. Moreover, between the orifices 32 and 33 having the smallest diameter, three fixed orifices having diameters larger than this orifice and different from each other are installed.
The damping force of the shock absorber may be adjusted in four or more stages. Further, in the specific example described above, the shutter moved rotationally, but instead of this, the shutter is configured to move in the axial direction to open and close a plurality of orifices arranged in the axial direction on the side circumferential surface of the guide. The encoder, stopper, etc. may be changed accordingly. Further, the stopper does not necessarily need to be provided near the shutter, but may be provided near the motor, and the motor may be replaced with a driving means such as a solenoid.

As described above, according to the present invention, the adjusting means for adjusting the magnitude of the damping force due to the liquid passage is provided so as to be movable in both forward and reverse directions in a predetermined direction of the piston rod, and at least four different positions in the predetermined direction. a shutter that moves to select the magnitude of the damping force due to the liquid passage, and when the shutter is at the beginning and end of its travel stroke and at least two other intermediate positions; Since the damping force of the hydraulic shock absorber is configured to generate the largest damping force in comparison, the damping force of the hydraulic shock absorber can be adjusted in at least three stages, and when the vehicle is in at least two intermediate positions where the damping force is small, If it is necessary to increase the damping force due to a sudden operation, move the shutter from its position before the sudden operation toward the starting end or the ending end, whichever is closer, where the shutter travel distance is shorter. can be moved in the forward or reverse direction, thus making it possible to immediately increase the damping force and reliably shorten the switching time for increasing the damping force.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a preferred specific example of the shock absorber according to the present invention, FIG. 2 is an enlarged view of the main parts of the shock absorber shown in FIG. 1, and FIGS. -H
It is a state explanatory diagram which shows the cross section along the line, and shows the relationship between the shutter and the fixed orifice, respectively. 1... Inner cylinder, 2... Outer cylinder, 7... Piston rod, 11... Piston, 13, 14... Oil chamber, 2
3, 25...Through hole, 24...Connecting rod, 38...
Guide, 29... Shyatsuta, 30, 31, 32,
33... Orifice, 34... Hole, 39... Motor.

Claims (1)

[Claims for Utility Model Registration] (1) A piston fitted into the cylinder to define two liquid chambers in the cylinder, one end connected to the piston, and the other end connected to the cylinder. A piston rod protruding outside the
a damping force generation valve provided on the piston to communicate the two liquid chambers; a liquid passage formed in the piston rod to bypass the damping force generation valve and communicate the two liquid chambers; The adjustment means is configured to adjust the magnitude of the damping force due to the liquid passage in at least three stages, and the adjustment means is provided so as to be movable in both forward and reverse directions in a predetermined direction of the piston rod, and the adjustment means is provided so as to be movable in both forward and reverse directions in a predetermined direction of the piston rod. The shutter has a shutter that moves to at least four positions to select the magnitude of the damping force, and when the shutter is at the beginning and end of its travel stroke, and when the shutter is at least two other intermediate positions. A hydraulic shock absorber characterized by being configured to generate the largest damping force compared to. (2) The hydraulic shock absorber according to claim 1, wherein the predetermined direction is the circumferential direction of the piston rod, and the shutter is rotatably provided.