JPH0313639Y2 - - 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 conventional hydraulic shock absorbers, for example, the shock absorber described in JP-A No. 58-24635, a damping force adjusting actuator is energized for a certain period of time to operate the actuator, and when the actuator is stopped, a stopper or the like is used. The actuator is forcibly stopped, and the damping force is adjusted in two stages. Furthermore, if an attempt is made to control the position of the actuator without using a stopping means such as the stopper, overrun or the like will occur due to the inertia of the actuator, making it difficult to stop the actuator at a predetermined position. Therefore, in order to improve the accuracy of the stop position of the actuator, the actuator is rotated at a low speed, so the damping force cannot be rapidly increased when the attitude of the vehicle body suddenly changes.

The present invention was devised in view of the above points, and its purpose is to accurately adjust the damping force by the actuator during normal driving, where sudden changes in the attitude of the vehicle body do not occur, and to prevent sudden changes in the attitude of the vehicle body. The object of the present invention is to provide a hydraulic shock absorber that can rapidly increase damping force when changing.

That is, the hydraulic shock absorber of the present invention includes a piston fitted into the cylinder to define two liquid chambers inside the cylinder, one end connected to the piston, and the other end connected to the outside of the cylinder. a damping force generating valve provided on the piston to communicate the two liquid chambers; and a damping force generating valve formed on the piston rod to bypass the damping force generating valve and communicating the two liquid chambers. a first switching position where the magnitude of the damping force by the liquid passage is a desired magnitude, and a second switching position where the magnitude of the damping force is larger than the desired magnitude. an adjusting means that can be switched; a driving means connected to the adjusting means to selectively drive the adjusting means at high speed or low speed; At times, the adjusting means is driven at low speed to the first switching position in order to select the desired damping force, and when a sudden change in attitude occurs in the vehicle body, the adjusting means is driven at a low speed to select the desired damping force.
and a control means for controlling the driving means so as to drive the adjusting means at high speed to a switching position.

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 1
7 and 18 constitute damping force generating valves. Further, the piston 11 has a chamber 1 branched from the passage 17.
A passageway is provided to keep 3 and 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 to flow from the chamber 14 to the chamber 13 through the passage 17, and closes when the value becomes smaller than a certain value P0, preventing the oil from flowing from the chamber 14 to the chamber 13 through 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. Further, a hexagonal columnar 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. 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 3 with different diameters are installed on the side circumferential surface of 8.
0, 31, 32 and 33 are bored, and when the shutter 29 is rotated within the guide 28 through the connecting rod 24, the fixed orifices 30, 31, 32 and 33 are selected through the hole 34 of the shutter 29. opened and closed. Fixed orifice 30, 31, 3
2 and 33 are guides 28 at angular intervals of about 60 degrees, respectively.
The orifices 32 and 33 are arranged at substantially opposite positions in the radial direction. The diameters of the orifices 30, 31, 32, and 33 decrease in the order of 30, 31, and 32,
The diameters of orifices 32 and 33 are substantially equal.
The hole 34 of the shutter 29 extends with a predetermined width on the side peripheral surface of the shutter 29, and this width is the width of the orifice 3.
The diameter of the orifice 30 is set to be smaller than the interval between 0 and 31, and larger than the diameter of the orifice 30, and functions as a movable orifice with respect to the fixed orifice. 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.
The output shaft of an actuator 42 consisting of an encoder 41 and an encoder 41 are connected to each other. That is, one end of an 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, and when the motor 39 is driven to rotate, , gear 40,4
0 and the encoder 41, the connecting rod 24 is rotated. On the outer peripheral surface of the upper end of the rod 7 is a nut 4.
A bracket 44 is fixed by 3, 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. The actuator 42, the drive circuit 46, and the pulse generation circuit 47 constitute a drive means, and the computer 4
8. Switches 49, 53 and sensors 50, 51,
52 constitutes a control means.

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. The high speed rotation of the motor 39 is transmitted to the shutter 29 in the same manner as described above, and the shutter 29 is rotated at a relatively high speed. At this time, when the hole 34 of the shutter 29 is rotated counterclockwise, for example from a position corresponding to the orifice 30 as shown in FIG. 3 to a position corresponding to the orifice 32 as shown in FIG. Similarly, the encoder 41 outputs a predetermined signal associated with the orifice 32,
The microcomputer receives this output signal via the feedback circuit and stops the motor 39 via the pulse generation circuit 47 and drive circuit 46. However, since the motor 39 and shutter 29 are rotating at a relatively high speed,
Due to the inertia of the motor 39 and the shutter 29, the shutter 29 does not stop immediately in response to the output signal from the encoder 41 and has a tendency to overrun. Therefore, in this case, the shutter 29 is connected to the encoder 4 at a position where the hole 34 communicates with the orifice 32.
The motor 39 is stopped in response to the output signal from the motor 39 by stopping power supply to the motor 39 and activating a stopping means such as a stopper. Such an operation is similarly performed when the shutter 29 is rotated from the position where the hole 34 corresponds to the orifice 31 to the position where the hole 34 corresponds to the orifice 33 by the high speed clockwise rotation of the motor 39. The pulse generation circuit 47 is capable of arbitrarily changing the output frequency, and thereby the rotational speed of the motor 39, that is, the adjustment speed of the damping force can be arbitrarily changed.

The stopper as the stopping means is the shutter 2
A groove (not shown) extending a predetermined length in the circumferential direction on the bottom surface of the disc 27
When the shutter 29 rotates counterclockwise, one end of the groove touches the protrusion at the position shown in FIG. When the shutter 29 is rotated clockwise, when the hole 34 comes to a position corresponding to the orifice 33, the shutter 29 is prevented from rotating further in the counterclockwise direction. The end of the shutter 29 comes into contact with the protrusion, and the shutter 29
is set such that further clockwise rotation of is prevented.

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 a position corresponding to the orifice 32 or 33, the damping force is largest, and when the hole 34 is in a 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 select the motor 3.
9 is rotated relatively slowly and intermittently at a low speed, and the hole 34 of the shutter 29 is placed in a position corresponding to the orifice 30 as described above, the damping force of the shock absorber is minimized, and a soft ride is achieved. Hole 34
If you place it at the position corresponding to the orifice 31,
The damping force is intermediate in magnitude, and a ride comfort between soft and hard is achieved, and in some cases hole 3
4 at a position corresponding to the orifice 32 or 33, a hard ride can be achieved.
Note that the selection of the ride comfort is automatically performed according to a predetermined speed according to the vehicle speed sensor 50.

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.

The specific example shown in FIGS. 6 to 9 has the same structure as the previous specific example except for the encoder 41, pulse generation circuit 47, and drive circuit 46. In this specific example, the output of the microcomputer 48 is transmitted to the motor 39 via a drive circuit 60.
The encoder 61 is a contact type encoder. The encoder 61 is
A code plate 62 having patterns A, B, and C as shown in FIG. 7, and a brush (not shown) that rotates around point 0 while contacting the patterns A, B, and C.
It is equipped with The brush is connected to the connecting rod 24 so as to rotate integrally with the shutter 29 in accordance with the rotation of the motor 39, and the brush is connected to the connecting rod 24 so as to rotate integrally with the shutter 29 in accordance with the rotation of the motor 39.
and C or while contacting patterns B and C;
A conductive state is established between patterns A and C or between patterns B and C, and a 2-bit signal related to each pattern is transmitted from the encoder 61 to the microcomputer 4.
8 is output. Sectors 63, 64, 65 and 66 related to patterns A, B, and C are provided on the code plate 62, and sectors 63, 64, 6
5 and 66 are arranged to correspond to the fixed orifices 30, 31, 32 and 33 shown in FIGS. 3 to 5, respectively. When the brush is on sector 63, patterns B and C are conductive; when the brush is on sector 64, sectors A and C are conductive; and when the brush is on sector 65 or 66, patterns B, C and pattern A and C become conductive, and a specific 2-bit signal is output to the microcomputer according to the conductive state of each, and it is determined which of the fixed orifices 30 to 33 the hole 34 of the shutter 29 corresponds to. be done. The positions of the motor 39 and the shutter 29 during rotational movement are detected by the intermittent pattern portions 67 to 70 between the sectors.

In this specific example as well, when an actuation signal is input to the microcomputer 48 through the mode select switch 49 or the vehicle speed sensor 50, the computer 48 sends the signal to the motor 3 via the drive circuit 60.
A drive signal is output to 9, and the motor 39 is rotated. For example, when the hole 34 of the shutter 29 is rotated clockwise from the position corresponding to the orifice 30 to the position corresponding to the orifice 31, the brush of the encoder 61 is rotated from the sector 63 to the sector 64, so that the pattern According to A and B, intermittent pulse signals D and E as shown in FIG. 8 are sent to the computer 48 by conduction between patterns A and C and between patterns B and C, respectively, . When it comes, the brush of encoder 61 will move to sector 6.
4, and the motor 39 and shutter 29 stop at that position without overrunning. During this time, since the rotation is clockwise, the pulse signal E is associated with the drive signal, and the signal D is
9 and a signal for detecting the rotational position of the shutter 29.

On the other hand, the throttle position sensor 51, the handle angle sensor 52, or the brake operation switch 5
When an operating signal is input to the computer 48 through the drive circuit 3, the computer 48 outputs a drive signal to the motor 39 via the drive circuit 60, causing the motor to rotate at high speed. For example, from the position where the hole 34 of the shutter 29 corresponds to the orifice 30,
2, the brush of the encoder 61 rotates counterclockwise from the sector 63 to the sector 65.
According to patterns A and B, pulse signals D and E as shown in FIG. Therefore, when the hole 34 of the shutter 29 comes to the position corresponding to the orifice 32, the transmission of the drive signal is stopped, and the motor 39 and the shutter 29 are stopped at that position by the stopper as in the above-mentioned embodiment. During this time, since the rotational direction of the motor 39 is counterclockwise, the pulse signal D is associated with the drive signal, and the pulse signal E is transmitted to the motor 39 and the shutter 2.
9 is associated with a signal for detecting the rotational position.

The pattern portions 67 to 70 between the sectors shown in FIG. When the brush comes into contact with the brush, the encoder 61 outputs alternate pulse signals D and E as shown in FIG. Pulse signals D and E shown in FIGS. 8 and 9 fall when signal D is conductive between patterns A and C, rise when they are not conductive,
This signal is set so that the signal E falls when the patterns B and C are conductive, and rises when the patterns B and C are non-conductive.

In the specific example described above, the stopper is provided near the shutter, but the stopper may be provided near the motor to restrict rotation of the shutter beyond a predetermined angle.

Further, in the specific example, four fixed orifices are provided, but among the fixed orifices, for example, one of the fixed orifices 33 and 32 may be omitted, or the interval between the fixed orifices may be changed. The encoder, the width of the shutter hole, the position of the stopper, etc. may be changed accordingly. Furthermore, five or more fixed orifices may be provided to adjust the damping force in four or more stages. In addition, when the motor 39 is intermittently rotated slowly and slowly, for example, the fixed orifice 30 or 31
The motor 39 and shutter 29 are rotated at a relatively high speed until the hole 34 reaches the vicinity of
The rotation of the motor 39 may be controlled so that the shutter 29 rotates slowly and intermittently at a low speed only until the hole 34 comes to the position corresponding to the orifice 30 or 31.

In addition, the width of the hole 34 of the shutter 29 is made larger than the gap between the orifices 31 and 33 to ensure communication of the liquid passage at all times, and when the hole 34 reaches the position corresponding to each orifice, the corresponding one The hole 34 may be formed with a width such that only one orifice communicates with the hole 34.

As described above, according to the present invention, during normal driving in which the vehicle body does not undergo sudden changes in attitude, the adjustment means for adjusting the damping force is moved at low speed to the first switching position. Therefore, the adjusting means can be accurately stopped at the first switching position without overrunning, and the adjustment means can be stopped at the first switching position accurately without overrunning, and it is also possible to prevent sudden changes in attitude of the vehicle body when the vehicle body is suddenly started, stopped, or suddenly turned. When this happens, the adjustment means for adjusting the damping force is moved to the second switching position at high speed, so the adjustment means is quickly switched to the second switching position and the damping force is made large. As a result, changes in the posture of the vehicle body can be suppressed as much as possible.

[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 part of Fig. 1, and Figs. 3 to 5 are taken along line HH in Fig. FIG. 6 is an explanatory diagram of a specific example in which the specific example shown in FIG. 1 is partially modified;
FIG. 7 is an explanatory diagram of the code plate of the encoder shown in FIG. 6, and FIGS. 8 and 9 are explanatory diagrams showing output signals of the encoder of FIG. 6, respectively. 1... Inner cylinder, 2... Outer cylinder, 7... Piston rod, 11... Piston, 13, 14... Oil chamber, 2
3, 25...Through hole, 24...Connecting rod, 28...
Guide, 29... shutter, 41... encoder.

Claims (1)

[Claims for Utility Model Registration] (1) A piston fitted into the cylinder to define two liquid chambers, one end of which is connected to the piston, and the other end of which is 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. a first switching position where the magnitude of the damping force caused by the liquid passage is a desired magnitude; and a second switching position where the magnitude of the damping force is greater than the desired magnitude. a driving means connected to the adjusting means to selectively drive the adjusting means at a high speed or a low speed; and a driving means connected to the adjusting means to drive the adjusting means selectively to drive the adjusting means at a high speed or a low speed. At this time, the adjustment means is driven at low speed to the first switching position in order to select the desired damping force, and when a sudden change in attitude occurs in the vehicle body, the damping force is changed to a large state. control means for controlling the driving means to drive the adjusting means at high speed to a switching position. (2) The adjustment means switches the magnitude of the damping force between two stages, a small state and a large state, and the first switching position is the state where the damping force is small. It is a position where
The hydraulic shock absorber according to claim 1, wherein the second switching position is a position where the magnitude of the damping force is large. (3) The hydraulic shock absorber according to claim 2 of the utility model registration, characterized in that an orifice of a predetermined diameter is provided at a position where the magnitude of the damping force is small. (4) The hydraulic system according to claim 3 of the utility model registration, characterized in that another orifice having a diameter smaller than that of the orifice is provided at a position where the magnitude of the damping force is large. buffer. (5) The scope of the utility model registration claim characterized in that the position where the magnitude of the damping force is large is located on both sides of the position where the magnitude of the damping force is small. Sections 2 to 4
Hydraulic shock absorber according to any one of paragraphs. (6) The adjustment means switches the magnitude of the damping force into three stages: a small state, a large state, and an intermediate state thereof, and the first
The switching position is either a position where the magnitude of the damping force is small or an intermediate state, and the second switching position is a position where the magnitude of the damping force is large. A hydraulic shock absorber according to claim 1 of the utility model registration claim, characterized in that: (7) An orifice with a predetermined diameter is provided at the position where the magnitude of the damping force is intermediate, and an orifice with a diameter larger than the one orifice is provided at the position where the magnitude of the damping force is small. The hydraulic shock absorber according to claim 6, characterized in that an orifice having a different diameter is provided. (8) Utility model registration claim 7, characterized in that another orifice having a smaller diameter than the one orifice is provided at a position where the magnitude of the damping force is large. Hydraulic shock absorber as described. (9) The utility model characterized in that the position where the magnitude of the damping force is large is located on both sides of the position where the magnitude of the damping force is small and intermediate. A hydraulic shock absorber according to any one of registered claims 6 to 8. (10) The hydraulic shock absorber according to any one of claims 1 to 9, which is a registered utility model, and further includes a stopper for stopping the adjusting means at the second switching position.