JPH03169732A - Support device - Google Patents

Abstract

PURPOSE:To improve vibration insulating properties and to save a consumption power by forming a support device, e.g. suspension, for an automobile with a linear motor and a resilient body positioned in parallel to the linear motor and controlling energization to the linear motor by means of a position detecting signal inputted through an LPF. CONSTITUTION:A support device comprises a linear motor 10 formed with a stator part and a moving part, magnetically combined with the stator part, and a resilient body 18 having a spring factor (k) located in parallel to the linear motor 10, and has the one end supported to a body 20 to be supported, e.g. the car body of an automobile. A relative position L from a reference position 24 of the body 20 to be supported is detected by a position detecting means 30, a detecting signal therefrom is inputted to a current control part 40 through an LPF 32, and a position command value responding to an operation command from a position control system 50 is inputted to a current control part 40. A feed current (i) to the linear motor 10 is controlled to erase a change component D of a low frequency outputted from the LPF 32.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a support device applied to an automobile suspension or the like, and particularly relates to a support device with excellent vibration isolation properties.

[Prior Art] FIG. 3 is a side view showing a conventional support device used in an automobile suspension.

In the figure, (1) is the car body of the supported body, (
2> is the axle supported by the vehicle body (1), (3> is the axle (2)
), (4> is the road surface that the tires (3) come in contact with. (5) is a shock absorber that suppresses the vibration of the car body (1), and the tire (4) is the road surface that the tires (3) come into contact with. The shock absorber (5) consists of an oil damper filled with fluid, etc. (6) is inserted between the sliding part of the shock absorber (5) and the vehicle body (1>). In this way, the conventional support device is an elliptical structure that combines a shock absorber (5) and a coil spring (6).

Next, while referring to the characteristic diagram in Figure 4 showing the vibration response of the vehicle body (1), we will discuss the operation of the conventional support device shown in Figure 3. If so, tires (3)
vibrates up and down, and this vibration is caused by a shock absorber (5
) and the coil spring (6) to the vehicle body (1). At this time, the response characteristic of the vibration of the vehicle body (1) to the vibration frequency f due to the unevenness of the road surface (4) is as shown in FIG. 4, for example.

In Fig. 4, the vertical axis is the amplitude ratio R of the vehicle body (1) to the tires (2), and the horizontal axis is the road surface (4), that is, the tire (2).
) side vibration frequency f. The broken line, the solid line, and the dashed-dotted line are characteristic lines when the damping force of the shock absorber (5) is changed, and the broken line shows the case where the damping force is small, the solid line shows the case where it is intermediate, and the dashed-dotted line shows the case where it is large. Furthermore, f is the resonant frequency of the sprung mass, that is, the vehicle body (1) side, f2 is the resonant frequency of the sprung mass, that is, the tire (2) side, and A is the human discomfort range.

From FIG. 4, the following (I) and (n) become clear regarding the damping force of the shock absorber (5).

(If the N damping force is small, the discomfort zone A is indicated by the broken line.)
However, the resonant frequency f,
The amplitude is large. Therefore, when the vehicle runs over an obstacle such as a protrusion on the road surface (4), the vibrations do not converge and become unstable, resulting in poor ride comfort.

(II) If the damping force is large, the resonance frequency f and f
There are almost no resonance points like 2, and the vibration convergence improves, but the responsiveness in the discomfort band A increases.
After all, the ride becomes uncomfortable.

Therefore, as a compromise in terms of ride comfort and stability, the damping force is set to be between (1) and (I[), as shown by the solid line.

Next, consider the strength of the coil spring (6). For example, pitching moment force due to braking or acceleration,
In addition, the rolling moment force due to turning becomes a force acting on the vehicle body (1), but in opposition to this, the rolling moment component force acts on the vehicle body (1).
In order to keep the posture angle of 1) constant, use the coil spring (6).
It is necessary to make it somewhat stiffer (increase the spring coefficient k). However, when the spring coefficient k is increased, the resonance frequency f1 on the vehicle body (1) side shifts and approaches the discomfort band A, resulting in poor ride comfort.

To solve this problem of ride quality, coil springs (6)
In addition to reducing the spring coefficient k of the shock absorber (
5) Set the damping force so that it follows the lowest line in Figure 4, vibration frequency f and discomfort band A → damping force large vibration frequency f =
Discomfort band A-+damping force small vibration frequency f> Discomfort band A
→It is necessary to set the damping force to medium. However, it is difficult to vary the damping force according to the region of the vibration frequency f due to the characteristics of the shock absorber (5) that uses hydraulic pressure.

Also, if the strength of the coil spring (6) is lowered, the vehicle may be suspended (
It is necessary to prepare another measure to stabilize the posture of 1). For this reason, for example, it is possible to use a known air spring or the like instead of the coil spring (6) and control the spring coefficient k by intake and exhaust, but this has the problem of poor responsiveness. [Problem to be solved by the invention] Since it is horizontally supported by the sober (5) and the coil spring (6), the vibration isolation property is poor, and when used in an automobile suspension, there is a problem that the riding comfort is poor. .

This invention was made in order to solve the above-mentioned problems, and an object thereof is to obtain a support device with excellent vibration isolation properties.

[Means for Solving the Problems] A support device according to the present invention includes a linear motor including a stator portion and a moving portion magnetically coupled to the stator portion;
A supported body supported by one of the stator part or the moving part,
A position detecting means for detecting the relative position of the supported body from the reference position, a low-pass filter for filtering a change in the relative position at a predetermined frequency or more, and a low-pass filter for canceling the change component output from the low-pass filter. The linear motor is provided with a current control section that controls the current supplied to the linear motor.

[Operation] The current supplied to the linear motor is controlled so as to normally generate an arbitrary constant thrust regardless of the stroke, and to cancel out the low frequency change component of the relative position of the supported body. As a result, the supported body is stably supported so that its absolute position remains constant against high-frequency relative position changes caused by uncontrolled vibrations, and even against changes in the height of the point of action or changes in the mass of the supported body. It is supported to follow relative position changes at low frequencies.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a configuration diagram showing one embodiment of the present invention, (10)
(20) is a supported body corresponding to a car body, (22) is a point of action corresponding to a car tire, and (24) is an uncontrolled vibration generation source corresponding to a road surface. (30) is a position detection means for detecting the relative position L of the supported body 20> from a reference position (for example, the road surface), and is composed of a differential transformer and a potentiometer.
32) is a low-pass filter that filters a changing component of a predetermined frequency (for example, human discomfort frequency) or higher at a relative position L, and (40> is a low-frequency changing precept D output from the low-pass filter (32)). Linear motor (
(50) a current control unit that controls the supply current i to 10);
is, for example, a position control system that inputs a position command value L ky according to an operation control command to a current control unit (4o). This shows the case of elliptical command using a coil-type electromagnetic actuator.

(11) is the outer yoke, (12> is the outer yoke (11)
and an inner yoke integral with the stator, which constitutes a double cylindrical stator section. (13) is the inner yoke (12)
It is a permanent magnet provided on the outer periphery of the magnet, and is magnetized in the radial direction. The permanent magnet (13) forms an elliptical stator portion together with the yokes (11> and (12)), and generates a closed loop magnetic field via each of the yokes (11) and (12) as shown by the arrow.

(14> is the output shaft inserted into the inner yoke, and constitutes a moving part that can slide in the vertical direction of the drawing. (15) is the output shaft (12) and the inner yoke (12).
4) is a slide bearing provided between the

(16) is a cylindrical electromagnet, or voice coil, which is integrated with the output shaft (14), is inserted between the permanent magnet (13) and the outer yoke (l1), and is magnetically coupled to the stator section.

Next, the operation of the embodiment of the present invention shown in FIGS. 1 and 2 will be explained.

When the relative position change of the supported body 20 due to controlled vibration etc. is not acting on the linear motor (10), the supply current i from the current control section (40) is constant, and the linear motor (10) is controlled to keep the thrust constant.

At this time, from the uncontrolled vibration source (24) to the point of action (22
) even if a high-frequency uncontrolled vibration is transmitted to the motor, if the frequency is higher than a predetermined frequency, the change component of the relative position WL is waved by the low-pass finoreta (32), so the change component D is subject to current control. section (40). Therefore, the supported body (20) does not follow high-frequency uncontrolled vibrations at all, and is stably supported so that its absolute position is constant. Next, let us assume that low frequency uncontrolled vibrations are transmitted from the uncontrolled vibration source (24) to the point of action (22>) when the car is climbing a hill. > detects the relative position L of the supported body (20) from the reference position from the slide movement amount (stroke) of the linear motor (1o), and the low-pass filter (32)
A low frequency variation component D of the relative position below a predetermined frequency is output.

The current control unit (40) determines the supply current i based on the change component D input to the low-pass filter (32), and controls the linear motor (IO) so as to cancel the change component D.Thereby, The supported body (2o) is supported so that the relative position L is constant, following the low frequency change component D. Also, due to changes in the mass of the supported body (2o), the linear motor (10 ) also changes, the relative position L changes at low frequency, so the supported body <
20) similarly cancels the change component D and tracks the relative position L to be constant. Here, if the initial position of the supported body (20) is L + and the position after movement is L2, then the position change amount ΔL is ΔL=L
It is expressed as 2-L. Also, if the constant supply current when there is no vibration is io, then the supply current i to the linear motor (10) is i=io+L"-L. However, the L flux is determined by various operation control commands, etc. This is a position command value of the supported body (20) that is set according to the following.

In this way, the supported body (20) is supported so that the relative position iL with respect to the reference position is constant, and can follow low-frequency position changes including controlled vibrations and the like. Therefore,
The linear motor (
Even if the load on 10) changes, the supported body (20>) will not become unsupportable.

Generally, the linear motor (10) generates thrust by spatial electromagnetic action, and this thrust does not depend on the slide position, so the supporting force does not change due to displacement of the point of application (22). Therefore, it is possible to realize a support device with extremely excellent high-frequency vibration isolation properties and high absolute position stability ability for the supported body (20). ), the thrust force can be independently controlled in the linear motor (10), and the supported body (20) has insensitivity to high-frequency uncontrolled vibrations, and It will follow changes in frequency. Therefore,
When used in an automobile suspension, vibrations in the range of human discomfort are not transmitted to the supported body (20), ie, the vehicle body.

In the above embodiment, the linear motor (10) is a voice coil type, but other linear motors, such as
It may also be an induction motor with conductors facing the polyphase primary windings.

Also, the position detecting means (30) is set to fI using a potentiometer or the like.
Although the relative position L of the supported body (20) was detected based on the amount of movement of the linear motor (10), the position detection means
30>, a height sensor is provided on the supported body (20),
The relative position L may be detected by directly measuring the height position to the road surface. Further, although the supported body (20) is fixed to the stator section of the linear motor (10), the direction of the linear motor (10>) may be reversed and fixed to the moving section.

"Effects of the Invention" As described above, according to the present invention, a linear motor including a stator part and a moving part magnetically coupled to the stator part, a supported body supported by either the stator part or the moving part, A position detecting means for detecting the relative position of the supported body from the reference position, a low-pass filter for filtering a change component of the relative position having a predetermined frequency or higher, and a low-pass filter configured to cancel the change component output from the low-pass filter. A current control unit is provided to control the current supplied to the linear motor, and normally the supplied current of the linear motor is constantly controlled so that the absolute position of the supported object is constant, and the Since the supported object is made to follow, high-frequency uncontrolled vibrations are not transmitted to the supported object, and a supporting device with excellent vibration isolation properties can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a sectional view showing a specific example of the configuration of the linear motor shown in FIG. 1, FIG. 3 is a side view showing a conventional support device, and FIG. The figure is a characteristic diagram showing the vibration response of the apparatus of FIG. 3. (10)... Linear motors (l1) to (l3)... Stator section (14), <16>... Moving section (20)... Supported body (30>... Position detection means (32)...Low pass filter (40)...Current control section L...Relative position D...Change component i...
Supply current In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A linear motor comprising a stator part and a moving part magnetically coupled to the stator part, a supported body supported by either the stator part or the moving part, and a reference position of the supported body. position detecting means for detecting a relative position from the linear motor; a low-pass filter for filtering a changing component of the relative position having a predetermined frequency or higher; and a current supplied to the linear motor so as to cancel the changing component output from the low-pass filter. A support device equipped with a current control section that controls.