JPH0373008A - Sliding type driver - Google Patents

Abstract

PURPOSE:To attain delicate position control of an output shaft by providing an output member which can be stroked in an axial direction, a coil for detecting position provided at this output member, and a magnetic material provided on a fixed side in a proximate state at this coil. CONSTITUTION:A stator 21 is formed in a cylindrical shape with a bottom by the magnetic material, and an annular magnet 24 is mounted at the outer circumference of an inner cylinder 23 provided at a through hole 22. Also, a movable coil part 28 of an amateur(output member) 27 is inserted to be freely slidable into an annular space 26, and a coil 29 for position detection is provided at the upper outer circumference. The slide of the output shaft 30 is supported at a bearing 31, and when the output member strokes, an induction current is generated in the coil for position detection, and by detecting the size of this induction current, the stroke position of the output member can be detected. Then, using this induction current as a feedback signal, a feedback control, which stops the output member at an arbitrarily position, made possible. Thus, the delicate control of the output member can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a slide type drive device most suitable for driving a damping force variable means of a hydraulic shock absorber.

(Prior art) Conventionally, as a slide type drive device, for example,
One known is the one used in the hydraulic shock absorber described in Japanese Patent No. 1-153032.

This slide type drive device has an electromagnetic solenoid with a pair of upper and lower coils and a pair of upper and lower coil springs. When both coils are not energized, the output shaft is placed in a neutral position, and the upper coil When electricity is applied, the output shaft moves to the upper position, and when electricity is applied to the lower coil, the output shaft moves to the lower position.

The damping force generated by the hydraulic shock absorber can be switched in three stages by using a slide-type drive device in which the output shaft is switched between three positions: upper, lower, and neutral. Ta.

(Problem to be Solved by the Invention) However, in such a conventional slide type drive device, since the output shaft is driven in one direction in stages,
Even when controlling the hydraulic shock absorber as described above, there is a problem in that the damping force can only be controlled in stages, and delicate control of the damping force cannot be performed.

In addition, even if the position is controlled in three stages, it is necessary to provide two coils, an upper coil and a lower coil, around the outer circumference of the plunger, which increases the length of the device in the axial direction and increases the size of the device. There were also problems.

The present invention was made by focusing on such problems,
It is an object of the present invention to provide a slide type drive device that enables delicate position control of an output shaft without increasing the size of the device.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the slide type drive device of the present invention includes an output member that can be stroked in the axial direction, a position detection coil provided on the output member, A magnetic body was provided on the fixed side in close proximity to the coil.

(Function) In the slide type drive device of the present invention, when the output member strokes, the position detection coil strokes within the magnetic field of the magnetic body provided close to it. As a result, an induced current is generated in the position detection coil, and by detecting the magnitude of this induced current, the stroke position of the output member can be detected.

Therefore, it is possible to perform feedback control in which the output member is stopped at an arbitrary position using this induced current as a feedback signal, thereby making it possible to perform delicate control of the output member.

Furthermore, since the stroke position of the output member can be detected at all times, fail-safe control is also possible in the event of a malfunction.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration of the embodiment will be explained. In this embodiment, a device for driving a damping force variable means of a hydraulic shock absorber will be explained as an example.

FIG. 2 is an overall diagram showing a damping force control system using a slide type drive device according to an embodiment of the present invention, in which l is a damping force variable hydraulic shock absorber, and 2 is a slide type drive according to an embodiment. In the apparatus, 3 is an acceleration sensor, 4 is a load sensor, and 5 is a controller.

The variable damping force type hydraulic shock absorber I is provided with a piston 12 that defines the inside of the cylinder 11 into an upper chamber A and a lower chamber B, as shown in FIG.

Furthermore, this piston 12 has a compression side communication passage 12a that communicates the upper chamber A and the lower chamber B, and through which the compression side damping valve 13 opens during the compression side stroke to obtain fluid circulation, and a compression side communication passage 12a that communicates the upper chamber A and the lower chamber B, and through which fluid circulation is obtained by opening the compression side damping valve 13 during the compression side stroke. An extension side communication path 12b is formed in which the damping valve i4 is opened and fluid circulation is obtained.

The piston 12 and the piston rod 15 have inner annular grooves 12c, 12d and an extension annular groove 12e.
, 2f are formed in the radial direction to bypass the inner sheet surfaces 12g and 12h. Variable orifices 18a, 18b are provided which can be changed to change damping force characteristics.

As mentioned above, the slide type drive device 2 slides the spool 18 up and down in order to change the opening degree of the variable orifices 18a, 18b of the variable damping force type hydraulic shock absorber l, and the details are shown in FIG. It shows.

That is, in the figure, 21 is a stator. The stator 21 is formed of a magnetic material into a cylindrical shape with a bottom, and an inner cylinder 23 that protrudes inward of the stator 2I is provided in a through hole 22 at the center of the lower part of the stator 21. An annular magnet 24 is attached to the outer periphery of the stator 21 with its lower surface in contact with the lower part of the stator 21, and an annular ball piece 25 is attached in contact with the upper surface of the magnet 24. .

In the annular space 26 formed between the outer peripheral surfaces of the magnet 24 and the pole piece 25 and the inner peripheral surface of the side wall of the stator 21, a moving coil of an armature (non-magnetic material) (output member) 27 is inserted from above. A portion 28 is slidably inserted.

This moving coil section 28 is for driving, and furthermore, in this embodiment, two position detection coils are provided on the upper outer periphery of this moving coil section 28.

The upper end of an output shaft 30 is fixed to the center of the base of the armature 27, and this output shaft 3o passes through the inner cylinder 23,
It is provided so that its sliding movement is supported by a bearing 3I. The lower end of this output shaft 30 is connected to the spool 18 (see FIG. 3).

A case 32 made of a non-magnetic material and having an open bottom is attached to the upper end opening of the stake 21, and the movable coil portion 2
A harness 34 is led out from the position detection coil 29 and the position detection coil 29 , and the harness 34 is connected to the controller 5 .

Next, returning to FIG. 2 and continuing the explanation, the acceleration sensor 3 outputs an electric signal a corresponding to the vertical acceleration on the spring. The load sensor 4 is provided as a relative speed measuring means for measuring the relative speed between the sprung and unsprung parts. Outputs a signal.

The controller 5 optimizes the damping force variable hydraulic shock absorber l based on the human power signals a and b from the acceleration sensor 3 and the load sensor 4, and the input signal (induced current i) from the position detection coil 29. It controls the voltage output to the slide type drive device 2 in order to obtain a damping force.

That is, this controller 5 includes an interface circuit 51 that inputs signals a and b from both sensors 3 and 4, an A/D conversion circuit 52 that converts the input analog signals into digital signals, and an input from the position detection coil 29. A feedback circuit 53 that converts the signal (induced current i) into a feedback signal f, and a CPU 5 that performs calculations and judgments based on the input signal and control contents stored in the memory circuit 54.
5. Drive circuits 56 and 57 are provided that output voltage to the slide type drive device 2 based on the calculation and determination results of the C:PU 55.

The drive circuits 56 and 57 apply a drive voltage to the movable coil section 28 of the slide type drive device 2 based on a combination of potential signals from the CPU 55, and the output terminal x
, Y determines the driving force and direction of the slide type driving device 2. In this embodiment, the spring 18c that biases the spool 18 is
The position of the spool 18 is determined by the balance with the urging force of the spool 18 (see FIG. 3).

The feedback circuit 53 also includes a high frequency oscillation circuit 53a that converts the induced current (direct current) i input from the position detection coil 29 into a high frequency sine wave AC, a detection circuit 53b that extracts a signal wave from the high frequency, and a signal wave A waveform shaping circuit 53c that extracts a part of the waveform from the CPU 55
is provided with an interface circuit 53d for inputting a feedback signal f. In this embodiment, as shown in FIG. 4, an LC oscillation circuit is used as the high frequency oscillation circuit 53a.

Next, the operation of this embodiment will be explained.

First, in the controller 5, based on the input signals a and b from the acceleration sensor 3 and the load sensor 4, the hydraulic shock absorber I
In order to obtain the optimum damping force, calculations are performed according to preset control details, and voltages are applied to the output terminals X and Y based on the calculation results.

In this slide type drive device 2, when the voltage from the controller 5 is applied to the movable coil portion 28 in the magnetic field, an electromagnetic force acts on the movable coil portion 28, and the armature 27 and the output shaft 30 are moved in the vertical direction. This causes the spool 18 to slide.

On the other hand, as the armature 27 and the output shaft 30 are driven,
When the position detection coil 29 slides in the magnetic field created by the magnetic material including the magnet 24, an induced current i is generated in the position detection coil 29, and by detecting this induced current i, the actual stroke of the spool 18 is determined. You can know the location.

That is, this induced current i is converted into a feedback signal f by the feedback circuit 53 and inputted to the CPU 55. Then, the CPU 55 constantly compares the calculation results based on the input signals a and b from the acceleration sensor 3 and the load sensor 4 and the control contents with the feedback signal f indicating the actual stroke position of the spool 18, and the feedback signal f is Control is performed to match the calculation result. Therefore, in the slide type drive device 2 of this embodiment, the induced current 1 generated from the position detection coil 29 is used as the feedback signal f to stop the output shaft 30 at an arbitrary position. Feedback control becomes possible, and as a result, the variable damping force type hydraulic shock absorber l has the characteristic that the damping force can be delicately controlled.

In addition, since the actual stroke position of the spool 18 can be detected at all times, if a problem occurs in which the relationship between the applied voltage and the position of the spool 18 is abnormal, it can be detected and appropriate abnormality control can be performed. It has the feature of enabling so-called fail-safe operation.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments. For example, in the embodiments, the slide type drive device is applied to a hydraulic shock absorber. is shown, but it can be applied to other things.

In addition, in the example, a variable damping force type hydraulic shock absorber with variable damping force on both the rebound side and the compression side was shown.
Either one is fine.

(Effects of the Invention) As explained above, in the slide type drive device of the present invention, the actual stroke position of the output member can be known by detecting the induced current generated in the position detection coil. It is possible to perform feedback control in which the output member is stopped at an arbitrary position using the induced current as a feedback signal, thereby achieving the effect that fine position control of the output member can be performed.

Therefore, even if the output member is driven in one direction, multi-step and stepless continuous control can be performed, and the device can be made more compact without increasing the size required for bidirectional driving. It will be done.

In addition, since the actual stroke position of the output member can be detected at all times, it is also possible to perform fail-safe control in the event of a malfunction.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a slide type drive device according to an embodiment of the present invention, Fig. 2 is an overall view showing a damping force variable system using the embodiment device, and Fig. 3 is a damping force using the embodiment device. FIG. 4 is a sectional view showing the main parts of the hydraulic shock absorber, and FIG. 4 is a block diagram showing details of the feedback circuit portion of the controller. 2--Slide type drive device l... Stator (magnetic material) 4... Magnet (magnetic material) 5... Ball piece (magnetic material) 9... Position detection coil 7... Amateur (Output member)

Claims (1)

[Claims] 1) An output member that is movable in the axial direction, a position detection coil provided on the output member, and a magnetic body provided on a stationary side in close proximity to the coil. A slide type drive device characterized by: