JP2002349630A - Friction control hydraulic buffer and suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate appropriate damping force to vibration of microamplitude in a hydraulic buffer. SOLUTION: A piston, to which a piston rod 3 is connected, is slidably fitted in the inside of a cylinder 2 in which oil liquid is sealed, and a damping force generating mechanism comprising an orifice, a disk valve or the like is provided to the piston. A guide retainer 8 is provided to an end part of the cylinder 2 and fixed together with a rod guide 4. A frictional element 15 and a portional solenoid 14 are provided to the inside of the guide retainer 8; and the frictional element 15 is pressed to a tapered face 16 of the guide retainer 8 by energizing a coil 11 and by an armature 12, the frictional element 15 is pressed to the piston rod 3 by reducing in diameter, and friction force makes the piston rod 3 act. Microamplitude vibration of, in which the damping force is hardly generated by the oil liquid, is damped by the friction force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction control hydraulic shock absorber capable of adjusting a friction force with respect to movement of a piston rod, and a suspension control device using the friction control hydraulic shock absorber.

[0002]

2. Description of the Related Art In general, in a vehicle suspension system such as an automobile, a hydraulic shock absorber is mounted together with a suspension spring between a vehicle body (above the spring) and wheels (below the spring). A hydraulic shock absorber generally has a cylinder filled with an oil liquid, a piston slidably fitted in the cylinder, one end connected to the piston, and the other end extending out of the cylinder. A piston rod is provided, and a flow of the oil liquid generated by sliding of the piston in the cylinder is controlled by a damping force generating mechanism including an orifice, a disc valve, and the like, to generate a damping force. The hydraulic shock absorber attenuates the vibration between the sprung and unsprung states and suppresses the change in the posture of the vehicle body, thereby improving the riding comfort of the vehicle and improving the steering stability.

Further, a damping force adjusting valve such as a shutter or a spool valve is provided in the oil passage in the above-mentioned hydraulic shock absorber, and the damping force can be adjusted by changing the flow area of the oil passage. There is a damping force adjustable hydraulic shock absorber. By appropriately adjusting the damping force according to the road surface condition, the running condition, and the like using the damping force adjusting hydraulic shock absorber, the riding comfort and the steering stability of the vehicle can be effectively improved.

[0004]

However, the above-mentioned conventional hydraulic shock absorber has the following problems. Since the damping force is generated by the flow resistance of the oil liquid, the piston rod needs to be stroked to some extent before the damping force is generated. Therefore, it is difficult to obtain a sufficient damping force for micro-vibration having a small amplitude. is there. Furthermore, since the effect of the piston speed on the damping force is large, it is difficult to set the damping force characteristics.

Further, in the damping force adjusting type hydraulic shock absorber, since a passage area of the oil liquid is adjusted by a damping force adjusting valve such as a shutter or a spool valve, a high-precision part is required, and the oil liquid is also highly purified. Since the degree is required, the manufacturing cost is increased.

The present invention has been made in view of the above points, and a friction control hydraulic shock absorber capable of obtaining a required damping force with a simple structure utilizing friction force, and such a friction control oil pressure. It is an object to provide a suspension control device using a shock absorber.

[0007]

According to a first aspect of the present invention, there is provided a friction control hydraulic shock absorber according to the first aspect of the present invention, which is slidably fitted in a cylinder filled with an oil liquid. Mounted piston, one end of which is connected to the piston, the other end of which is extended to the outside of the cylinder, and a piston rod. A hydraulic shock absorber provided with a damping force generating mechanism for generating a force, wherein a frictional force adjusting means for adjusting a frictional force with respect to the movement of the piston rod is provided. With this configuration, the damping force is generated by controlling the flow of the oil liquid, and the damping force is controlled by adjusting the frictional force directly acting on the piston rod by the frictional force adjusting means. In the friction control hydraulic shock absorber according to the second aspect of the present invention, in the configuration of the first aspect, the frictional force adjusting means generates a friction element in contact with the piston rod and an axial thrust of the piston rod. It is characterized by including a linear motion actuator and pressing means for pressing the friction element against the piston rod by the thrust of the linear motion actuator. With this configuration, the friction element is pressed against the piston rod by the linear actuator to control the frictional force. In the friction control hydraulic shock absorber according to a third aspect of the present invention, in the configuration of the first aspect, the frictional force adjusting means generates a frictional element that contacts the piston rod and a rotational force about an axis of the piston rod. And a pressing means for pressing the friction element against the piston rod by a rotating force of the rotating actuator. With this configuration, the frictional force is controlled by pressing the friction element against the piston rod by the rotary actuator. Further, a suspension control device according to a fourth aspect of the present invention provides a suspension control device according to the first aspect, wherein the friction control hydraulic shock absorber is interposed between a vehicle body and wheels of the vehicle. Means, and a controller for controlling the frictional force adjusting means of the friction control hydraulic shock absorber based on the detection signal of the detecting means. With this configuration, the frictional force acting on the piston rod of the friction control hydraulic shock absorber is controlled based on the traveling state of the vehicle such as the vehicle speed, the dive of the vehicle body, the squat, the roll, the traveling point, etc. Control vibration and posture changes.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. A first embodiment of the friction control hydraulic shock absorber according to the present invention will be described with reference to FIG. The friction control hydraulic shock absorber according to the present embodiment has the same structure as that of the conventional hydraulic shock absorber described above, with respect to a hydraulic shock absorber main body having a damping force generation mechanism for controlling a flow of an oil liquid to generate a damping force. Therefore, only the characteristic portions will be illustrated and described in detail below.

FIG. 1 shows the end of the cylinder 2 in the friction control hydraulic shock absorber 1 on the piston rod 3 side. A friction control hydraulic shock absorber 1 has a piston (not shown) slidably fitted in a cylinder 2 in which oil is filled, similar to a conventional normal hydraulic shock absorber. Three
Is connected, and the other end of the piston rod 3 is slidably inserted into a rod guide 4 and an oil seal 5 attached to the end of the cylinder 2 and extends to the outside. An outer cylinder 6 is provided on the outer periphery of the cylinder 2, and an annular reservoir 7 in which oil and gas are sealed is formed between the cylinder 2 and the outer cylinder 6. The reservoir 7 is connected to the cylinder 2 via a base valve (not shown) provided at the lower end of the cylinder 2. The piston is provided with a damping force generating mechanism (not shown) including an oil passage, an orifice, a disk valve, and the like.

A guide retainer 8 having a substantially cylindrical shape with a bottom is attached to an end of the cylinder 2, and a piston rod 3 is inserted through an opening 9 at the bottom. The guide retainer 8 has a rod guide 4 fitted to the open end of the cylindrical portion thereof, and a cap 10 attached to an end of the outer cylinder 6 to move the rod guide 4
It is fixed with. The guide retainer 8 has a coil 11, an armature 12, and a return spring 13, and is capable of moving the armature 12 along the piston rod 3 in accordance with a current flowing through the coil 11, and a proportional solenoid 14 (linear actuator). ) Is provided.

A cylindrical friction element 15 through which the piston rod 3 is inserted is attached to the tip of the armature 12 and is inserted into an opening 9 at the bottom of the guide retainer 8. Opening 9
Tapered surfaces 16 and 17 (pressing means) which face each other are formed on the inner peripheral portion and the outer peripheral portion of the friction element 15, respectively.
The friction element 15 is provided with several notches (not shown) radially, and opens the tapered surface 17 of the friction element 15 attached to the tip of the armature 12 by the thrust of the proportional solenoid 14.
By pressing against the tapered surface 16 of 9, the friction element 15 is reduced in diameter and pressed against the piston rod 3, and the piston rod 3
A frictional force is applied to the stroke of the vehicle. In FIG. 1, reference numeral 18 denotes a bush, 19 denotes a check valve, and 20 denotes a retainer spring.

The operation of the embodiment constructed as described above will be described below. Like a conventional normal hydraulic shock absorber,
The damping force is generated by controlling the flow of the oil liquid generated by the sliding of the piston in the cylinder 2 with the orifice of the damping force generating mechanism, the disc valve, and the like with respect to the stroke of the piston rod 3. At this time, the volume change in the cylinder 2 due to the penetration and retreat of the piston rod 3 is compensated by the compression and expansion of the gas in the reservoir 7.

When the coil 11 of the proportional solenoid 14 is energized,
The taper surface 17 of the friction element 15 is pressed against the taper surface 16 of the guide retainer 8 by the armature 12, and the friction element 15 is reduced in diameter and pressed against the rod guide 3. Can act. In this way, by applying a frictional force to the stroke of the piston rod 3, the vibration of the piston rod 3 can be damped, and a change in the attitude of the vehicle body can be suppressed to improve the steering stability. it can.

At this time, the frictional force on the piston rod 3 acts stably irrespective of the stroke amount and the stroke speed (piston speed) of the piston rod 3, so that it is difficult for the ordinary hydraulic shock absorber to attenuate. Micro vibration can be effectively damped.

Then, according to the current flowing through the coil 11,
Since the frictional force can be adjusted, the frictional force can be controlled according to the running state of the vehicle. Generally, piston rod
If the frictional force with respect to (3) is increased, the stability of the vehicle body will be improved, and if the frictional force is reduced, the ride comfort will be improved. Properties can be effectively improved. In the above-described embodiment, an on-off type solenoid, a piezoelectric element, a magnetostrictive element, or the like may be used as the driving means of the friction element 15 instead of the proportional solenoid 14.

Next, a second embodiment of the friction control hydraulic shock absorber according to the present invention will be described with reference to FIGS. Note that the same reference numerals are given to the same parts as those shown in FIG. 1, and only different parts will be described in detail.

As shown in FIG. 2, in the friction control hydraulic shock absorber 21 of this embodiment, a substantially cylindrical guide retainer 22 having a bottom is attached to the end of the cylinder 2, and a piston rod is attached to the bottom of the guide retainer 22. 3 are inserted and slidably guided by a bush 18. Guide retainer 22
An annular retainer 23 through which the piston rod 3 is inserted is screwed to an open end of the cylindrical portion, and is fixed together with the retainer 23 by a cap 10 attached to an end of the outer cylinder 6.

A pair of friction elements 24 and 25 are provided at the bottom of the guide retainer 22 with the piston rod 3 interposed therebetween. As shown in FIG. 3, the pair of friction elements 24 and 25 are arc-shaped sliding contact portions 26 and 27 that are in sliding contact with the outer peripheral surface of the piston rod 3.
And a pair of cam grooves formed at the bottom of the guide retainer 22.
28, 29 (pressing means) and pins 30, 31 (pressing means) to be inserted, and by applying a rotational force about the axis of the piston rod 3, the pins 30, 31 Moving along 29, the sliding portions 26 and 27 are pressed against the piston rod 3. The pair of friction elements 24 and 25 are axially supported by a snap ring 32. The cam groove
28 and 29 are formed so as to gradually decrease in diameter in the rotation direction, whereby the sliding contact portions 26 and 27 are pressed against the piston rod 3.

In the cylindrical portion of the guide retainer 22, there is provided a rotary (rotational) actuator 35 (ultrasonic motor) comprising an annular rotor 33, a stator 34, a piezoelectric element 34a provided on the stator 34, and the like. Rotary actuator 3
5 energizes the piezoelectric element 34a of the stator 34,
A traveling wave is generated by a, and the rotor 33 is driven by the ultrasonic wave. The rotor 33 is engaged with the pair of friction elements 24 and 25, and the rotational force of the rotor 33 causes the friction elements 24 and 25 to move along the cam grooves 28 and 29 that guide the pins 30 and 31, The sliding portions 26 and 27 are pressed against the piston rod 3. Guide retainer 22, retainer 2
3, an exploded view of the friction elements 24, 25 and the rotary actuator 35 is shown in FIG.

Next, the operation of the embodiment constructed as described above will be described. By vibrating the piezoelectric element 34a provided on the stator 34 of the rotary actuator 35 and rotating the rotor 33, the pair of friction elements 24 and 25
Along the cam grooves 28 and 29 for guiding the sliding contact portions 26 and 27
Is pressed against the piston rod 3 to exert a frictional force on the stroke of the piston rod 3. As a result,
As in the first embodiment, by applying a frictional force to the stroke of the piston rod 3, the vibration of the piston rod 3 can be damped, thereby suppressing a change in the posture of the vehicle body and improving the steering stability. Can be. Then, by adjusting the torque of the rotary actuator 35 in accordance with the running state of the vehicle to control the frictional force, it is possible to effectively improve the riding comfort and the steering stability of the vehicle.

In the above embodiment, a rotary solenoid, a stepping motor or the like may be used as the rotary actuator instead of the ultrasonic motor.

Next, an embodiment of a suspension control device using the friction control hydraulic shock absorber of the first and second embodiments will be described with reference to FIG. 5 to FIG.

FIG. 5 shows the configuration of one wheel of the suspension control device according to this embodiment. As shown in FIG.
A suspension between the vehicle body 36 and the wheels 37 is provided with a suspension spring 38 and a friction control hydraulic shock absorber 39. The friction control hydraulic shock absorber 39 is a friction force adjusting means 40 for controlling a friction force acting on the piston rod according to an external signal such as a current.
For example, the friction control hydraulic shock absorbers of the first and second embodiments can be used. A microprocessor-based controller 41 is connected to the frictional force adjusting means 40. The controller 41 receives detection signals of various sensors 42 for detecting the driving state of the vehicle, processes these signals based on a predetermined logical rule, and controls the frictional force adjusting means 40 of The force is calculated, and a command signal is output to the frictional force adjusting means 40. In FIG. 5, reference numeral 43 denotes a road surface.

The control flow of the controller 41 is shown in FIG.
This will be described with reference to FIG. 6 and FIG. As shown in FIG. 6, in step, initial setting is performed, and in step, the control cycle is determined and adjusted. Output, output signals to various indicators etc. in steps,
In a step, information representing the driving state of the vehicle is input from various sensors 42, and in a step, a necessary frictional force is calculated based on the information.

Next, when executing various controls,
A subroutine for calculating the required frictional force in the steps will be described with reference to FIG.

[0026] (1) frictional force controlled basically based on the vehicle speed, increasing the frictional force of the friction force adjusting unit 40 of the hydraulic shock absorber 39, improved steering stability of the vehicle, ride comfort is reduced, friction When the amount is reduced, the steering stability tends to decrease and the riding comfort tends to improve. Therefore, the sensor 42
As a vehicle speed sensor, as shown in FIG. 7, the vehicle speed is determined in step S1, and if the vehicle speed is equal to or less than the set value, the frictional force is reduced in step 2, and if the vehicle speed exceeds the set value, in step S3 Increase the frictional force.

Thus, in a low speed range, the riding comfort can be improved by a small frictional force, and in a high speed range, the steering stability can be improved by a large frictional force, and both the riding comfort and the steering stability can be achieved. . Note that a wheel rotation speed sensor may be used as the vehicle speed sensor.

(2) As the anti-dive control sensor 42, detection means for detecting vehicle deceleration, brake switch, brake oil pressure, vehicle body pitch angle, throttle opening, longitudinal acceleration, vertical acceleration, and the like are used. The dive of the vehicle body is detected based on the
In, the dive state of the vehicle body is determined instead of the vehicle speed,
In the non-dive state, the frictional force is reduced in step S2, and in the dive state, the frictional force is increased in step S3. Thus, dive of the vehicle body during braking or the like can be suppressed, and the posture of the vehicle body can be stabilized.

In this case, after the vehicle body dives to some extent and a damping force is generated by the hydraulic pressure of the friction control hydraulic shock absorber 39,
The frictional force may be reduced. The detection of the dive state can be determined by elapse of a certain time after the dive occurs.

(3) As the anti-squat control sensor 42, detection means for detecting vehicle acceleration, engine speed, vehicle body pitch angle, throttle opening, longitudinal acceleration, vertical acceleration, and the like are used, and the vehicle 7, the squat state of the vehicle body is determined in place of the vehicle speed in FIG. 7, and in the non-scott state, the friction force is reduced in step S2, and in the squat state, the friction force is increased in step S3. I do. Thus, the squat of the vehicle body at the time of starting or the like can be suppressed, and the posture of the vehicle body can be stabilized.

In this case, the frictional force may be reduced after the vehicle body is squatted to some extent and a damping force due to the hydraulic pressure of the hydraulic shock absorber 39 is generated. The detection of the squat state can be determined by elapse of a predetermined time after the occurrence of the scott.

(4) The anti-roll control sensor 42 includes a vehicle lateral acceleration, a steering angle, a steering angular velocity,
Using the detection means for detecting the vehicle speed, the roll speed, the roll angle, and the like, the occurrence of the roll of the vehicle body is detected based on these output signals, and the roll state of the vehicle body is determined in FIG. In the roll state, the frictional force is reduced in step S2, and in the roll state, the frictional force is increased in step S3. Thereby, the roll of the vehicle body at the time of turning or the like can be suppressed, and the posture of the vehicle body can be stabilized.

In this case, the frictional force may be reduced after the vehicle body rolls to some extent and a damping force due to the hydraulic pressure of the hydraulic shock absorber 39 is generated. The detection of the roll state can be determined by elapse of a predetermined time after the occurrence of the roll.

(5) As the friction control sensor 42 based on the traveling point information, a detecting means for detecting the traveling point using GPS or the like is used. Condition (straight road, curved road,
(Good road, bad road, etc.), and in FIG. 7, the state of the traveling road is determined in place of the vehicle speed.
The frictional force is reduced in S2, and on a good road or a curved road, the frictional force is increased in Step S3. As a result, it is possible to effectively absorb the vibration from the road surface and suppress the change in the posture of the vehicle body, and it is possible to improve the traveling performance.

In this case, when a traveling point can be specified in advance, such as a railway car, the point information can be directly taken in without using GPS or the like.

[0036] (6) as a damping control sensor 42, the spring, the acceleration of the unsprung acceleration change rate, the absolute velocity, the relative velocity, the vehicle height, using a detection means for detecting a road surface information or the like, to these output signals 7, the vibration state of the vehicle body is determined in place of the vehicle speed, and if the vibration is small, the frictional force is reduced in step S2, and if the vibration is large, S3
To increase the frictional force. Thereby, the vibration of the vehicle body can be effectively damped, and the riding comfort can be improved.

In this case, the frictional force can be controlled by the so-called skyhook theory based on the absolute speeds of the sprung and unsprung states.

In the above examples (1) to (6), the frictional force of the frictional force adjusting means 40 is controlled in two stages. However, the frictional force may be controlled in multiple stages or continuously according to the running state. it can.

In each of the above-described embodiments of the friction control hydraulic shock absorber according to the present invention, the hydraulic shock absorber main body for controlling the flow of the oil liquid to generate the damping force may be a hydraulic shock absorber having a fixed damping force. The present invention can also be applied to a variable damping force type hydraulic shock absorber capable of adjusting a damping force.For example, by performing control in which damping force control and friction control of a variable damping force type hydraulic shock absorber are performed, High-precision steering stability and ride comfort control become possible.

[0040]

As described in detail above, according to the friction control hydraulic shock absorber according to the first aspect of the present invention, the provision of the friction adjusting means allows the damping force to be generated by controlling the flow of the oil liquid. The damping force can be controlled by adjusting the frictional force acting directly on the piston rod by the frictional force adjusting means. At this time, the frictional force against the piston rod acts stably irrespective of the stroke amount and stroke speed (piston speed) of the piston rod, so it is effective for micro-vibrations that are difficult to attenuate with a normal hydraulic shock absorber. Can be controlled effectively. According to the friction control hydraulic shock absorber according to the second aspect of the present invention, the frictional force can be controlled by pressing the friction element against the piston rod by the linear motion actuator.
According to the friction control hydraulic shock absorber according to the third aspect of the present invention, the frictional force can be controlled by pressing the friction element against the piston rod by the rotary actuator. Further, according to the suspension control device according to the fourth aspect of the present invention, the friction acting on the piston rod of the friction control hydraulic shock absorber based on the vehicle speed, the dive of the vehicle body, the squat, the roll, the traveling point, etc. By controlling the force to control the vibration and the change in attitude of the vehicle, it is possible to effectively improve the riding comfort and the steering stability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a first embodiment of a friction control hydraulic shock absorber according to the present invention.

FIG. 2 is a longitudinal sectional view showing a main part of a second embodiment of the friction control hydraulic shock absorber according to the present invention.

FIG. 3 is a cross-sectional view of the apparatus of FIG. 2 taken along the line AA.

FIG. 4 is an exploded longitudinal sectional view of a frictional force adjusting means of the apparatus of FIG.

FIG. 5 is a block diagram showing one embodiment of a suspension control device according to the present invention.

FIG. 6 is a flowchart of control by a controller of the apparatus in FIG. 6;

FIG. 7 is a diagram showing a subroutine of the flowchart in FIG. 6;

[Explanation of symbols]

1,21 Friction control hydraulic shock absorber 2 Cylinder 3 Piston rod 15,24,25 Friction element (friction force adjustment means) 14 Proportional solenoid (friction force adjustment means, linear actuator) 16,17 Tapered surface (pressing means) 28, 29 Cam groove (pressing means) 35 Rotary actuator (friction force adjusting means, rotary actuator) 36 Body 37 Wheel 39 Friction control hydraulic shock absorber 40 Friction force adjusting means 41 Controller 42 Sensor (detection means)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Tsukuma 1-6-3 Fujimi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Tokiko Corporation (72) Inventor Satoshi Osawa 1-6-1-3, Fujimi, Kawasaki-ku, Kawasaki-ku, Kanagawa Prefecture No. Tokiko Corporation F term (reference) 3D001 AA02 AA18 BA01 DA03 DA17 EA07 EA22 EA32 EA34 EA42 EA43 EA72 EB32 ED02 ED04 3J069 AA50 EE62 EE65 EE68

Claims (4)

[Claims] 1. A cylinder filled with an oil liquid, a piston slidably fitted in the cylinder, and a piston having one end connected to the piston and the other end extending outside the cylinder. In a hydraulic shock absorber including a rod and a damping force generating mechanism that generates a damping force by controlling a flow of an oil liquid generated by sliding of the piston in the cylinder, adjusting a frictional force with respect to movement of the piston rod. A friction control hydraulic shock absorber, comprising: 2. The frictional force adjusting means includes: a frictional element in contact with the piston rod; a linear actuator for generating a thrust in the axial direction of the piston rod; 2. The friction control hydraulic shock absorber according to claim 1, further comprising pressing means for pressing the piston rod. 3. The frictional force adjusting means includes: a frictional element in contact with the piston rod; a rotary actuator for generating a rotational force about an axis of the piston rod; and a rotational actuator for rotating the frictional element by the rotational force of the rotary actuator. 2. The friction control hydraulic shock absorber according to claim 1, further comprising pressing means for pressing the piston rod. 4. The friction control hydraulic shock absorber according to claim 1, interposed between a vehicle body and wheels of a vehicle, detection means for detecting a running state of the vehicle, and a detection signal of the detection means. A controller for controlling a frictional force adjusting means of the friction control hydraulic shock absorber based on the controller.