JPH0756311B2 - Damping force adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a damping force adjustment in a case where a ratio of the extension side to the compression side of the damping force is variable in a variable expansion ratio adjusting type damping force adjustable shock absorber system for a vehicle. A method and an apparatus thereof.

<Prior Art> In order to improve the riding comfort of the vehicle while traveling, appropriate damping force is generated only near the primary and secondary resonance points specific to the vehicle body (specific to the shock absorber used), and in other vibration regions. There is no damping force, and the damping force near the resonance point is low on the compression side and high on the extension side. Various damping force adjustable shock absorbers have already been proposed.

By the way, according to the conventional shock absorber of this kind,
As shown in FIG. 6, the damping force characteristics were three-step control with two steps of soft (S) and hard (H) or one step added in the middle. And, in general, for large shake of the vehicle body during roll control or nose dive control,
A control mode is adopted in which the damping force is hardened to suppress a change in posture.

In addition, when driving at high speed, the damping force on the front wheel (front) side is set to a higher level (hard) in advance, and the fact that a large vibration input has entered this front side can be detected by various sensors such as displacement sensors, ultrasonic sensors, or gravity sensors. When it is detected by the sensor, the damping force on the rear wheel (rear) side is switched to the hard side to cope with the vibration from the road surface coming into the rear wheel following the front wheel, and the vehicle body vibration can be suppressed to a small number. Riding comfort and maneuverability have been improved by switching to an appropriate mode according to the running condition of the stage control mode.

<Problems to be Solved by the Invention> However, even in the conventional shock absorber that improves the riding comfort by changing the expansion ratio as described above,
There are still drawbacks, and there is a strong need for improvement.

That is, in the above-mentioned conventional shock absorber, even when the damping force is switched, the damping force can be set at the same time on both the expansion side to generate a high damping force or a low damping force. If you switch to the hard side, the vehicle body vibration can be suppressed, but the feeling of pushing up is large and the riding comfort becomes worse, and if you set the damping force low to prevent this feeling of pushing up, the body vibration due to insufficient damping force will increase. However, the compatibility has not been fully satisfied.

Therefore, an object of the present invention is to provide a damping force adjusting method and an apparatus thereof, which makes it possible to generate the optimum damping force at that time by a relatively simple control that achieves both the alleviation of the feeling of thrust and the prevention of vehicle body vibration. That is.

<Means for Solving Problems> In order to achieve the above-mentioned object, the device of the present invention has a structure in which a piston rod is movably inserted into a cylinder, and two chambers are defined by the piston in the cylinder. The two chambers communicate with each other through a port common to the piston rod formed on the piston rod and a port on the pressure side, and a rotary valve controlled by one actuator is rotatably inserted into the piston rod. In the damping force adjusting device, a first through hole that is opened and closed by the common port for expansion and a second through hole that is opened and closed by the compression side port are formed in the first through hole. The second through hole is gradually narrowed from one end to a predetermined position, and is gradually narrowed from this predetermined position to an arbitrary position. Wide groove width Further, it is characterized in that the groove width is gradually narrowed again from this arbitrary position to form a slotted hole.

<Operation> According to the damping force adjusting device, long groove holes with partially different groove widths flow hydraulic oil according to the groove width of different parts under the regulation of the hole diameter of the common port for expansion or the pressure side port facing this. Since it acts as an adjusting orifice that allows the oil flow amount, the damping force is regulated by adjusting the amount of flowing oil depending on the rotational position of the rotary valve, that is, the occupied position of the elongated groove with respect to the port.

Further, since the shape of the long groove which is the first passage for the common port for expansion and the shape of the long groove which is the second passage for the compression side port are changed, it is possible to make the damping force generation ratio between the expansion side and the compression side variable. In addition, these slotted slots can be smoothly moved steplessly when switching to each mode position.

<Embodiment> As shown in FIG. 3, a shock absorber constituting a damping force adjusting device has a piston rod 1 movably inserted into a cylinder 8 via a piston 9, and the piston 9 has two caps. The chambers A and B are divided, and the two chambers A and B are communicated with each other through a common port 3 formed in the piston rod 1, a compression side port 6, and a passage 10 in the piston rod 1.

Further, in the piston portion, an extension main valve 15 that generates an extension side damping force when oil flows from the volume chamber A to the volume chamber B, and a pressure main that generates a compression side damping force when oil flows from the volume chamber B to the volume chamber A. A valve 16 is provided. The ports 3, 6, and passage 10 bypass the main valves 15, 16.

A rotary valve 2 whose rotation is controlled by a single actuator P via a control rod 14 is rotatably inserted into the piston rod 1, and the rotary valve 2 is opened / closed to a port 3 for common expansion and a port 6 on the pressure side. Through holes are formed.

1 and 2 respectively show one embodiment of the rotary valve 2 constructed according to the present invention. FIG. 1 (a) is a sectional view of the rotary valve 2 facing the port 3 for common expansion and FIG. 2B is a development view of the peripheral surface. 2 (a) is a side view of the rotary valve 2 facing the pressure side port 6, and FIG. 2 (b) is a development view of the peripheral surface thereof.

In the rotary valve 2 formed in the piston rod 1,
A long slot 4 which is a wedge-shaped first through hole is formed in which the groove width gradually narrows from one end to the other in the clockwise direction, leaving a part of the peripheral wall facing the common port 3 for expansion. I am doing it. On the other hand, as shown in FIGS. 2 (a) and 2 (b), the portion facing the pressure side port 6 having the check valve 5 at the open end has a groove width in the clockwise direction, leaving a part of the peripheral wall. A second wedge-shaped wedge that widens the groove width through the narrowing singularity and then narrows again.
The long slot 7 which is a through hole is opened.

That is, the slot 7 has a groove width gradually narrowed from one end to a predetermined position, gradually widened from the predetermined position to an arbitrary position, and then gradually narrowed again from the arbitrary position. There is. Moreover, these both slots 4 and 7 are formed at positions where the rotational positions a, b, c and d shown in FIGS. 1 and 2 coincide with each other. Then, as will be described later, in the mode 1, mode 2 and mode 3, the slotted holes 4 and 7 are opened to the expansion common port 3 and the pressure port 6 as shown in FIG. 4, for example. Is shut off like. Moreover, the flow rate of each port 3, 6 and the damping force at that time are 6th
Shown in the figure.

More specifically below, when the piston rod 1 moves in the cylinder 8 together with its piston 9 in response to the vibration operation, the oil in the cylinder contents chambers A and B is transferred to the common port 3 for expansion.
And the pressure side port 6, the long groove holes 4 and 7 of the rotary valve 2, and the passage 10 of the piston rod 1 through the oil feed passage, and the piston 9 flows to the other chamber.

If the rotary valve 2 holds its rotationally occupied position a as shown in FIG. 4 during this piston operation, the expansion side operation of the piston rod 1 causes the compression side closed by the state of the check valve 5. Port 3 with common extension for port 6
Since the flow of the hydraulic oil having the widest groove width of the long groove hole 4 which coincides with the adjustment orifice as the adjustment orifice flows between the upper and lower chambers without receiving the resistance to the left, the damping force is generated at this time.
As shown in the characteristic diagram of FIG. 7, the characteristic curve M1 in the extension side damping force range is as shown in FIG.
Since the check valve 5 is opened, in addition to the flow of the hydraulic oil passing through the port 3 for common expansion, the hydraulic oil that is regulated by the wide groove portion at the occupied position a of the long groove hole 7 passes through the pressure side port 6. As a result of the addition of the above flow, the state becomes as shown by the characteristic curve M1 of the upper pressure side damping force region in FIG. That is, this damping force control mode is set to the first mode.

Similarly, if the rotary valve 2 holds the rotational occupied position b, the characteristic curve higher than that in the I-mode on the extension side is obtained.
The damping force of M2 is generated, and in the pressure side operation, the damping force of the characteristic curve M2 higher than that in the first mode is generated by the adjusting orifice function of the singular point position b where the groove width is narrow. That is, these states are set to the second mode.

Furthermore, when the rotary valve 2 is in the rotational occupied position c,
Since the groove width of the long groove 4 is further narrowed, while the groove width of the long groove 7 is widened again, the characteristic on the extension side is higher than that of the second mode, and the characteristic on the pressure side is higher than that of the first mode and lower than that of the second mode. The damping force generation state of the third mode, which is indicated by the characteristic curve M3III in FIG. 4, is obtained.

At the rotational position d where both ports 3 and 6 are closed by the cutoff portions 4a and 7a of the rotary valve 2, respectively, the extension main valve 15 is used in the extension side operation, and the pressure main valve 16 is used in the pressure side operation. As a result, the hydraulic fluid flows only through this, and the control state of the fourth mode in which the damping force at that time becomes extremely high as shown by the characteristic curve M4 in FIG. 4 can be obtained.

As shown in FIG. 5, the controller 11 compares the state detection signals from various sensors such as a suspension displacement sensor, a vehicle speed sensor, a steering wheel angular velocity sensor, a throttle position sensor, an acceleration sensor or a brake pressure sensor as shown in FIG. When the calculation is performed, for example, when the signal value from each of the above-mentioned sensors is less than or equal to a certain set value, the damping force mode switch 12 is set so as to select the first mode, and the rotary mode is output by the switch 12. It controls one actuator that determines the rotationally occupied position of the valve 2. Therefore, during normal traveling in which these sensors detect a relatively stable traveling state, a comfortable ride control with a small damping force in the first mode is performed.

Then, when the suspension displacement sensor, the vehicle speed sensor, and the acceleration sensor each detect a value equal to or higher than a fixed installation value, that is, when vibration near the primary resonance point is likely to occur, the damping force is output by the controller 11. The mode switcher 12 selects the second mode to generate a relatively large damping force on both the compression side and effectively act as balancing control and bottoming control.

Further, the switching to the third mode is performed by the occurrence of vibration near the secondary resonance point when traveling on a rough road when the switching sensor to the second mode detects a larger value.

A certain value from the vehicle speed sensor, steering wheel angular velocity sensor, throttle position sensor, brake pressure sensor, etc. when there is a risk of vibration with large amplitude such as nose-down at the time of sudden start or sudden stop and bounce scout or rolling. The signal can be switched to the fourth mode, and the attitude can be well controlled under the generation of extremely high damping force at that time.

<Effects of the Invention> According to the present invention, there are the following effects.

The first passage is formed by a wedge-shaped slotted groove with the groove width gradually narrowed, and the second passage is gradually narrowed to a predetermined position.
Since the groove width is gradually widened from this predetermined position to an arbitrary position, and is gradually narrowed again from this arbitrary position, it is damped according to the rotation of the rotary valve on the extension side. 1st, 2nd, 3rd, 4th which can gradually increase force characteristics
At this time, the first mode, the second mode higher than the first mode on the pressure side, the third mode higher than the first mode and lower than the second mode, and the fourth highest mode at the same time can be set.
The damping force characteristic of the mode is obtained.

The rotary valve is controlled by one actuator.
Since the second, third and fourth modes are set, the structure is simple and the controller can be simplified and the power supply capacity can be reduced.

[Brief description of drawings]

1 and 2 are configuration diagrams of a rotary valve showing an embodiment of the device of the present invention. In each drawing, (a) is a sectional view, (b) is a development view of a peripheral surface, and FIG. 3 is a rotary. FIG. 4 is a vertical cross-sectional view of a main part showing an example of a shock absorber to which a valve is applied, FIG. 4 is a partially enlarged cross-sectional view showing a rotary valve position in the first mode, and FIG. 5 is a rotary valve position in the fourth mode. FIG. 6 is a partially enlarged cross-sectional view showing the table, FIG. 6 is a table showing the flow rate of the port and the magnitude of damping force in each mode, FIG. 7 is a characteristic diagram showing each characteristic of the damping force setting mode,
FIG. 8 is a configuration diagram showing an example of a control system in the device of the present invention, and FIG. 9 is a characteristic diagram showing a damping force setting mode in a conventional system. 1 ... Piston rod, 2 ... Rotary valve, 3 ...
Common port for expansion, 4, 7 ... long groove hole, 6 ... compression side port, 8 ... cylinder, 9 ... piston, a to d ... rotational position, 1 to 4 ... first mode to first 4 modes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-182506 (JP, A) SAIKAI 59-121220 (JP, U)

Claims (1)

[Claims] 1. A piston rod is movably inserted into a cylinder through a piston, and two chambers are defined by the piston in the cylinder. The two chambers are formed in the piston rod and are a common port for expansion. Through a pressure side port, a rotary valve that is rotationally controlled by one actuator is rotatably inserted in the piston rod,
In the damping force adjusting device, the rotary valve has a first through hole that is opened and closed by the common port for expansion and a second through hole that is opened and closed by the pressure side port. The hole is composed of a long slot having a groove width gradually narrowed from one end to the other end, and the second through hole is gradually narrowed from one end to a predetermined position, and from this predetermined position to an arbitrary position. The damping force adjusting device is characterized in that the groove width is gradually widened, and the groove width is gradually narrowed again from this arbitrary position.