JPH05252722A - Linear motor device - Google Patents

Abstract

PURPOSE:To detect the present position with high accuracy at real time by constituting a position detector out of an electrode plate and an insulating member, which fixes and supports the electrode plate to a base, and detecting the change of capacitance occurring between the electrode plate and a slider. CONSTITUTION:This device is equipped with a guide means, which guides a slider 2 reciprocating on a base plate 1, and a slider driver 3, which energizes the slider 2 to reciprocate. A position detector 21 for a slider 2 is equipped between the base plate 1 and the slider 2. The position detector 21 is composed of an electrode plate 21A, which is opposed to one side of the slider 2, and an insulating member 21B, which fixes the electrode plate 21A to the base plate 1 and supports it. The position detector 21 is provided with a C-F converter and an F-V converter, which detects and outputs the change of the capacitance occurring between the electrode plate 21A and the slider 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor device, and more particularly to a linear motor device having a slider drive controller and a position detector.

[0002]

BACKGROUND ART Many linear motor devices have been developed more than ever before, from small to precision machinery and precision measurement fields to large to railway technology. And
Many studies have been made in the past not only on the drive control means for the moving object but also on the technique for detecting the position.

[0003]

However, there are few examples of the means for detecting the position of a moving object in a precision instrument capable of continuously measuring a small distance change with high accuracy and continuously.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a position detecting means capable of continuously measuring the current position of a slider, which is a moving object, with high accuracy and continuously in consideration of such a fact in the prior art. It is an object of the present invention to provide a provided linear motor device.

[0005]

According to the present invention, a base plate, plate-like sliders arranged in parallel to the base plate at a predetermined distance, and guides the slider to reciprocate on the base plate. A guide means and a slider drive control unit provided between the base plate and the slider for urging the slider to reciprocate are provided. A position detector for the slider is provided between the base plate and the slider, and the position detector is provided with an electrode plate facing one surface of the slider and an insulating member for fixing and supporting the electrode plate to the base plate. And a C-F converter that detects a change in capacitance between the electrode plate and the slider and outputs the detected change as a cycle of the detection signal, and an output of the C-F converter is a voltage signal. It is equipped with an F-V converter that converts to and output. This aims to achieve the above-mentioned object.

[0006]

First, when the slider drive controller is operated, the slider moves in a predetermined control direction. Along with the movement of the slider, the facing area x between the slider and the electrode plate changes as shown in FIG. 6, whereby the electrostatic capacitance between the slider and the electrode plate changes. This change in capacitance is C
In the -F converter, the frequency is converted and output as a change in the cycle of the detection signal. And the output of this CF converter is
The voltage is converted by the F-V converter and output as a display voltage signal corresponding to the current position of the slider.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment shown in FIG. 1, a plate-shaped base plate 1, a slider 2 arranged in parallel on the base plate 1 at a predetermined distance, and a slider 2 mounted on the base plate 1 for driving and controlling the position of the slider 2. And a plurality of rollers 4A, 4B, 5A, 5B which are provided on both sides of the base plate 1 and which form a part of guide means and guide the reciprocating movement of the slider 2 described above. It has and. The base plate 1 is made of a rectangular flat plate as a whole, and has mounting portions 1A and 1B slightly above the left and right ends of FIG. Further, a stopper 1C for the slider 2 is provided in the central upper portion of the base plate 1 shown in FIG. 1, and a mounting portion 1E is provided in the central lower portion of the figure. The slider drive control unit 3 is mounted on the slider 2 side of the central portion of the base plate 1. The slider 2 is made of a magnetic material, and is also made of a rectangular flat plate as a whole, and a projecting portion 2A is provided at the upper center portion of FIG. Then, a driven body (not shown) is attached to the protruding portion 2A.
Are engaged.

Of the plurality of rollers 4A, 4B, 5A, 5B, the rollers 4A, 4B on one side are arranged at predetermined intervals along the moving direction of the slider 2 as shown in FIGS. Has been done. The rollers 4A and 4B are spherical rollers. V-shaped grooves 1V and 2V for guiding the spherical rollers 4A and 4B are formed in the base plate 1 and the slider 2 described above, respectively.
Further, the rollers 5A and 5B are cylindrical rollers, and are also arranged at predetermined intervals along the moving direction of the slider 2. Each of these rollers 4A, 4B, 5
A and 5B have spur gears 6 of the same size on their outer circumferences.
7, 8 and 9 are rotatably mounted. This spur gear 6
9 to 9 are formed of plastic in this embodiment, but may be formed of other members. A through hole of a predetermined size is provided in the center point portion of the spur gears 6 to 9, and the rollers 4A, 4B, 5 described above are provided in the through hole portion.
Each of A and 5B is rotatably incorporated. Rollers 4A, 4B, 5 equipped with these spur gears 6 to 9 separately
Racks 10, 11, 12, and 13 that mesh with these spur gears 6 to 9 are provided at the equipment locations of A and 5B.

More specifically, two parallel base plate side concave grooves 1M and 1N are formed at both end portions on the base plate 1 along the reciprocating direction of the slider 2 described above. Further, slider-side recessed grooves 2M and 2N, which are formed substantially the same, are provided on the slider 2 side so as to face the two base-plate-side recessed grooves 1M and 1N.
Among these, the above-mentioned V-shaped grooves 1V and 2V are provided in the openings of the one concave grooves 1M and 2M, respectively. Then, the base plate side concave grooves 1M and 1N and the slider side concave grooves 2M and 2
Each of the Ns is equipped with the racks 10, 11, 12, and 13 described above. In this case, the spur gears 6 and 7 are always meshed with the racks 10 and 11, respectively. Also,
The spur gears 8 and 9 are always meshed with the racks 12 and 13, respectively. These racks 10 to 13 and spur gears 6 to
At the time of meshing of No. 9, the backlash is set so as to have the maximum size, and in some cases, the pitch circles are assembled in such a manner that they are slightly separated. As a result, the weight of the slider 2 is set so as not to be applied to the racks 10-13.

A position detector 21 for the slider 2 is provided between the base plate 1 and the slider 2 as shown in FIGS. The position detecting section 21 includes an electrode plate 21A arranged opposite to one surface (the lower surface in FIG. 2) on the slider 2 and separately arranged at two places on the left and right sides in the drawing, and the electrode plate 21.
Is fixed to the base plate 1 by an insulating member 21B. The position detector 21 includes an electrode plate 21.
A C-F converter 22 that detects a change in electrostatic capacitance between A and the slider 2 and outputs the detection signal as a change in the cycle, and an output of the C-F converter 22 as a voltage signal. An F-V conversion unit 23 for converting and outputting is also provided. As a result, a slight amount of movement of the slider 2 is accurately detected and output as described later.

Next, the operation of the above embodiment will be described. First, in the state shown in FIGS. 1 and 2, the slider 2 is supported by one roller 4A, 4B, which is a spherical roller, and the other roller 5A, 5B, which is a cylindrical roller, and these rollers 4A, 4B, Via 5A and 5B,
It reciprocates on the base plate 1 in the directions of arrows A and B.

Now, when the slider drive control unit 3 urges the slider 2 from the intermediate position (the position indicated by the solid line in FIG. 5) in the direction of arrow A in FIG. Move to position ₁ by distance L ₁ . In this case, the rollers 4A, 4B, 5A, 5B have a moving distance of the rotation center of L _1/2 . When the slider drive control unit 3 biases the slider 2 in the direction of arrow B from the intermediate position, the tip of the slider 2 moves to the position of arrow P ₂ in FIG. 5 by the distance L ₂ . Also in this case, the roller 4A,
4B, 5A, 5B, the center of rotation is moved by L _2/2 while supporting the slider 2. In this case, slider 2
Stroke is L ₁ + L ₂ . L ₀ indicates the allowable stroke range, and d indicates the diameter of the stopper. The slider 2 is controlled by the slider drive controller 3 in the directions of arrows A and B (within the range of stroke L ₁ + L ₂ ).
It can be repeatedly moved back and forth or stopped at a predetermined position on the way.

On the other hand, along with the reciprocating movement of the slider 2, the four rollers 4A, 4B, 5A and 5B supporting the slider 2 also reciprocate over a distance of 1/2 of the slider 2. During this time, the spur gears 6 mounted on the rollers 4A, 4B, 5A, 5B
9 also reciprocates while meshing with racks 10-13.
Here, the pitch circle (PCD) of the spur gears 6 to 9 is the roller 4
Larger than A, 4B, 5A, 5B diameter. Therefore, the rotation angles of the spur gears 6 to 9 are smaller than the rotation angles of the rollers 4A, 4B, 5A, 5B. That is, the rollers 4A, 4B, 5
The A and 5B and the spur gears 6 to 9 reciprocally move integrally within a range of a distance (L ₁ + L ₂ ) / 2 while appropriately slidingly contacting each other. Due to the action of the spur gears 6 to 9 and the racks 10 to 13, the rollers 4A, 4B, 5A and 5B accurately repeat their original positions and pass without any positional deviation.

As described above, the slider 2 includes the spur gears 6-9.
By the action of the racks 10 to 13 and the rollers 4A, 4B, 5A, 5B, the reciprocating movement is set with high precision, but at the same time, the position after the movement is precisely measured by the position detecting section 21. FIG. 6 shows the movement of the slider 2 in this case. In FIG. 6, reference symbol S indicates the movement amount of the slider 2, L _O indicates the stroke of the slider 2,
x represents measured value (L _O over S). Now, when the slider 2 moves in the direction A in the figure, the facing area x between the slider 2 and the electrode plate 21A changes, and thereby the electrostatic capacitance between the slider 2 and the electrode plate 21A changes. The change in the capacitance is frequency-converted and output as a change in the cycle of the detection signal in the CF converter 30. The output of the C-F converter 30 is voltage-converted by the F-V converter 31 and externally output as a display voltage signal corresponding to the current position of the slider 2.

The experimental results are shown in FIG. As shown in FIG. 7, the position after the movement of the slider 2 is output to the outside as a voltage value with high accuracy and that is easy to drive the display means.
Here, the relationship between the frequency f and the capacitance C is f = 1 /
Since it is [2π · (LC) ^1/2 ], the smaller the value of the capacitance C, the better the linearity between the frequency f and the capacitance C. Therefore, the output of the C / F converter 22 described above can frequency-convert the change in the cycle of the detection signal output from the position detector 21 with high accuracy and output it. Therefore, the current position of the slider 2 is converted with high accuracy from the FV conversion unit 23 at the final stage and output as the display voltage value V _S.

[0016]

Since the present invention is constructed and functions as described above, according to this, even when the slider is slightly moved, this can be easily detected by the electrostatic capacitance type position detecting portion as a change in electrostatic capacitance. Since the electrode plate is opposed to the slider, the structure is very simple, and the current position of the slider can be directly measured regardless of the moving speed of the slider. It is possible to provide an unprecedented excellent linear motor device that can detect and output the current position of the device with high accuracy.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a block diagram showing an electric system that processes an output signal of a position signal detection unit in FIG.

FIG. 4 is an enlarged partial sectional view taken along line BB of FIG.

5 to 6 are explanatory views showing the operation of FIG.

FIG. 7 is a diagram showing an example of the experimental results of FIGS. 3 and 6.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base plate 2 Slider 3 Slider drive control unit 21 Position detection unit 21A Electrode plate 21B Insulation member 30 C-F conversion unit 31 F-V conversion unit

Claims (1)

[Claims] 1. A base plate, a plate-shaped slider arranged in parallel with the base plate at a predetermined distance, guide means for guiding the slider to reciprocate on the base plate, the base plate and the slider. And a slider drive control unit for urging the slider to reciprocate, and a slider position control unit is provided between the base plate and the slider. Is composed of an electrode plate disposed so as to face one surface of the slider and an insulating member for fixing and supporting the electrode plate to the base plate, and a capacitance of the electrostatic capacitance generated between the electrode plate and the slider. A C-F converter that detects a change and outputs it as a change in the cycle of the detection signal, and the output of this C-F converter is converted into a voltage signal. A linear motor device equipped with an output F-V converter.