JPS63120927A - Variable shock absorber - Google Patents

Abstract

PURPOSE:To obtain a high torque with a thin type shockabsorber, by employing a supersonic motor as an actuator for switching the damping force of a variable shockabsorber. CONSTITUTION:Piezoelectric vibration chips 12, 13 are lapped and sticked concentrically over a stator base body 14 and used as a stator 15. When the stator 15 is driven, a traveling wave is excited in the stator 15 to move the top point of vibration at the side facing with a moving body 23 as the time elapses, thereby force for moving the moving member 23 in the circumferential direction is applied onto the moving member 23 thus producing a rotary motion. Consequently, a variable shockabsorber having a structure where the rotary shaft 25 of a supersonic motor and a control rod 9 are coupled directly can produce a high torque with thin structure without requiring a speed reduction mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a variable shock absorber for a vehicle that is capable of achieving both ride comfort and handling stability by changing the damping force depending on the running condition of the vehicle. It is something.

2. Description of the Related Art Suspensions for conventional vehicles generally use a combination of a shock absorber with a certain damping force, a spring, and the like.

However, the damping force of this shock absorber is determined to be suitable for normal constant-speed driving conditions, but when starting suddenly or driving around a curve, the shock absorber cannot support the vehicle body enough to cause the vehicle to sag (sagging) or cause centrifugal force. This causes the vehicle to tilt (roll), making the ride uncomfortable. Furthermore, there is a drawback that the steering stability deteriorates when accelerating from a medium speed.

In recent years, with remarkable progress in electronic control technology, products have begun to be commercialized that achieve both ride comfort and handling stability by switching the damping force of shock absorbers depending on various driving conditions (Japanese Patent Laid-Open No. 58-65341) ).

A schematic diagram of the general structure of a variable shock absorber is shown in FIG. A piston 3 is slidably housed in a pace shell 2 arranged inside an outer cylinder 1, and the upper end of a hollow piston rod 4 whose lower end is fixed to the piston 3 is configured to be supported by the vehicle body.

Further, the lower end of the pace shell 2 is supported toward the wheel side.

In the extension stroke, the oil 6 in the upper chamber of the piston flows into the lower chamber through the pulp of the piston 3 part. At this time, a damping force is generated. Oil pressurized with nitrogen gas flows from the reservoir chamber 6 into the lower chamber through the communication path 7 so that the lower chamber does not have a negative pressure and generate cavity silane.

During the contraction stroke, the oil 6 in the lower piston chamber flows into the upper piston chamber and the reservoir chamber 6. When flowing into the upper chamber,
Damping force is generated by the pulp of the three piston parts.

In the above configuration, the control rod 9 inserted into the hollow part of the piston rod 4 has a built-in rotary pulp 10 connected to it in which large and small boats are provided in the radial direction, and an actuator connected to the upper part of the control rod 9. 11 is driven to rotate the rotary pulp 10, and by overlapping the large and small boats of the rotary pulp 10 with the boats of the piston 3, the flow rate of the oil 5 is changed and the damping force of the shock absorber is adjusted.

Problems to be Solved by the Invention Although DC motors, solenoids, and the like have been proposed as actuators for switching the damping force of variable shock absorbers, these systems have the following problems.

1) Since the output torque per unit volume of the DC motor is small, a fairly large actuator for switching the variable shock absorber damping force is required.

r+) DC motors are highly efficient at high speed and low torque.

Since this region is used as an actuator for switching variable shock absorber damping force, a reduction mechanism for torque amplification is required.

111) When switching the damping force in multiple stages, positioning is difficult with a solenoid, and a new mechanism for positioning, an encoder for position detection, etc. are required.

The present invention solves the above problems and provides a practically excellent variable shock absorber device.

Means for Solving the Problems The present invention effectively solves the above problems by using an ultrasonic motor as an actuator for switching the damping force of a variable shock absorber.

Function When an ultrasonic motor is used as an actuator in this way, a thin ultrasonic motor with high torque can be obtained, so a variable shock absorber that is smaller and more efficient than conventional ones can be obtained.

EXAMPLE An example of the present invention will be described below. First, the ultrasonic motor will be explained. An ultrasonic motor is a motor that uses ultrasonic vibration as its driving force. Electrical input excites minute elastic vibrations in a vibrating body, and this motion is converted into motion of a moving body.

The vibrating body has a structure as shown in FIG. 2, for example. The disk-shaped piezoelectric vibrator 12 is provided with eight electrodes divided into regions, for example, every 45 degrees, on the surface thereof. Polarization is performed such that the polarization directions of adjacent electrodes of the piezoelectric vibrator 12 configured in this manner are different from each other in the thickness direction. As a result, as shown in Figure 2, 8 regions consisting of regions with alternately positive or negative polarity
Four sets of forced excitation oscillators are formed. After polarization, the electrodes do not need to be divided and can be connected together so that a voltage can be applied.

The disk-shaped piezoelectric vibrator 13 has a similar structure to the piezoelectric vibrator 12, and is formed with four sets of eight poles and four sets of forced excitation vibrators having alternating positive and negative polarities.

The piezoelectric vibrators 12 and 13 configured as described above are attached to the stator base 14 so as to overlap concentrically, and are used as the stator 15 shown in FIG. 3. As shown in FIG.
is applied to the electrodes of the piezoelectric vibrator 13 via lead wires 19 and 20 to excite a standing wave. On the other hand, the phase-shifted signal from the oscillator 16 is shaped by the phase shifter 21 and then sent to the amplifier 18.
is applied to the electrodes of the piezoelectric vibrator 12 via lead wires 20 and 22 to excite a settled wave. Since the two standing waves are out of phase, a traveling wave whose maximum amplitude position moves in the circumferential direction with time is excited in the stator 16.

A movable body 23 is in contact with the top of the stator 15.

The moving body 23 includes a slider 24 made of a wear-resistant material or the like and an elastic body 26 having a rotating shaft 26.

The rotating shaft 25 is coupled to the control rod 9 of the shock absorber as shown in FIG.

When the stator 15 is driven as described above, a traveling wave is excited in the stator 16. That is, since the peak of vibration on the side facing the moving body 23 moves with time, a force is applied to the moving body 23 so that it moves in the circumferential direction, and rotational motion can be obtained.

The ultrasonic motor described above has the advantage of being able to constitute a motor with an extremely simple structure and excellent responsiveness, and being thin and capable of obtaining high torque.

As described above, the variable shock absorber having the structure in which the rotating shaft 26 of the ultrasonic motor and the control rod 9 are directly connected 1) does not require a speed reduction mechanism; 11) Has holding power without applying voltage to the motor.

111) Since the motor is thin, the overall length of the absorber does not become long. This has the advantage that a practically excellent shock absorber can be constructed.

In the structure of the shock absorber, the actuator part is omitted.

A shaft 26 is formed on the surface of the moving body 23 and is directly connected to the control rod 9 of the shock absorber. Ultrasonic motors have high torque output and do not require a speed reduction mechanism. In addition, in this embodiment, a gear mechanism is provided on the outer periphery of the moving body 23 of the ultrasonic motor, and by meshing with the drive gear 28 directly connected to the control rod 27 for changing the spring constant of the suspension, the suspension is adjusted. The spring constant of the silane is also changed.

As described above, the damping force of the shock absorber is determined by driving the stator 15 of the ultrasonic motor, rotating the movable body 26, and fixing the control 9 at a predetermined position. Since the ultrasonic motor has a large holding force without applying voltage, it is possible to prevent the control rod 14 from shifting from its resting position due to external forces such as vibrations. Also, D
Since it has better starting and stopping characteristics than the C motor, it can reach the target rotational position in a short time, and accurate positioning is possible by attaching a simple sensor to the target rotational position.

Effects of the Invention As described above, the ultrasonic motor of the variable shock absorber of the present invention is thin and has high torque, so it can be directly connected to a control rod, and the overall length can be made shorter than that of conventional shock absorbers. Furthermore, since the holding force is constant even without applying voltage, it is possible to maintain an accurate stationary position. It has excellent effects such as

[Brief explanation of the drawing]

FIG. 1 is a sectional front view of a variable shock absorber according to an embodiment of the present invention, FIG. 2 is an ultrasonic motor, and FIG. 4 is a sectional front view of a conventional variable shock absorber. 1... Outer 1j, 2... Pace shenope 3... Piston, 4... Piston rod, 5... Oil, 6... ...Reservoir chamber, 7...Communication path, 8...Tube,
9... Control rod, 10... River/rotary pulp, 11... Actuator, 12
．． 13... Piezoelectric vibrator, 14... Stator base, 15... Stator, 16... Oscillator, 17.18... Amplifier, 19.20.2
2... Lead wire, 21... Phase shifter, 2
3...Moving object, 24...Slider, 2
5...Rotating shaft, 26...Elastic body, 27
...Control rod, 28...Gear. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 fq, 2022-9-do beads Figure 4

Claims (3)

[Claims] (1) In a vehicle variable shock absorber device that changes the damping force depending on the driving condition, a disc-shaped stator base and a disc-shaped piezoelectric vibrator are laminated concentrically as an actuator that changes the damping force. A variable shock absorber device characterized by using a disk-type ultrasonic motor that rotates a movable body placed in pressurized contact with a stator formed by driving the stator. (2) The variable shock absorber device according to claim 1, which has a structure in which a control rod for changing the damping force of the variable shock absorber and a rotating shaft provided on the surface of the moving body of the ultrasonic motor are directly connected. . (3) A gear mechanism is provided on the rotating shaft provided on the outer periphery of the moving body of the ultrasonic motor or on the surface of the moving body, and this gear mechanism is engaged with a control rod drive gear for changing the spring constant of the suspension. 2. The variable shock absorber device according to claim 1, wherein the spring constant of the suspension is thereby also changed.