JP2000314606A - Linear position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect signal even with a large gap between a stator and a rotor by providing a surface of the rotor facing to the stator with a waveform part which the gap permeance to the stator varies as sine wave against moving distance. SOLUTION: To a stator 1 having a plurality of projected magnetic poles 2 placed by exciting winding 3 and two-phase output winding 4, a long rotor 5 reciprocally movable is provided. On the opposite side of the rotor 5 to the stator 1, a waveform part 6 repeating with a specific period is formed so that the gap permeance to the stator 1 varies in sine wave to the moving distance. With this constitution, by impressing a specific exciting signal to the exciting winding 3 of the stator 1 and linearly moving the rotor 5, SIN output voltage and COS output voltage are output from the two-phase output winding 4 and so with this two-phase output voltage. By calculating tan-1 (SIN output/COS output) from the two-phase output voltage, linear position signal is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear position detecting device, and more particularly, to a linearly movable member having a longitudinally extending movable member having a sinusoidal wave-shaped portion whose gap permeance with a stator varies sinusoidally. And a new improvement for detecting contactlessly.

[0002]

2. Description of the Related Art A linear encoder, a magnescale, an Absocoder (registered trademark) and the like are conventionally used as this kind of linear position detecting device.

[0003]

Since the conventional linear position detecting device is configured as described above, there are the following problems. That is, for both the linear encoder and the magnescale, the resolution cannot be obtained unless the clearance between the movable side and the fixed side is small, or the output signal is too small to detect, so the use is limited. Also,
For the ABSOCODER, the movable side (fixed side) is fixed side (movable side)
Because of the structure that passes through the coil, the use is limited. Therefore, when a linear motor is used at a high speed, the dimensions of the motor mechanism change due to heat generation and the like, and the gap between the movable side and the fixed side of a linear table or the like changes. Detection was difficult with an encoder and a magnescale. Also,
The contact type sensor has a problem in durability at the time of high-speed use.

SUMMARY OF THE INVENTION The present invention has been made in order to detect the above-described problems. In particular, a wave-shaped portion in which a gap permeance with a stator changes in a sinusoidal manner is formed on a longitudinal movable element. It is an object of the present invention to provide a linear position detecting device that detects a change in the linear position of a child without contact.

[0005]

According to the present invention, there is provided a linear position detecting device comprising: a movable member having a linear longitudinal shape; and a stator having an exciting winding and an n-phase output winding corresponding to one surface of the movable member. A wave portion formed on one surface of the mover facing the stator and having a gap permeance with the stator that changes in a sinusoidal manner with respect to a moving distance, and an excitation signal is input to the excitation winding. By moving the mover in the state, a linear position signal is output from the output winding.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a linear position detecting device according to the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a stator having a plurality of projecting magnetic poles 2. Each magnetic pole 2 is provided with an exciting winding 3 and a two-phase output winding 4 shown in FIG. Corresponding to the stator 1, a longitudinal movable element 5 is provided so as to freely reciprocate linearly. On one surface of the movable element 5 facing the stator 1, a corrugated portion 6 that repeats at a predetermined cycle is formed. I have.
The waveform portion 6 is configured so that the gap permeance with the stator 1 changes in a sinusoidal manner with respect to the moving distance. Note that a gap d is formed between the lower end of the stator 1 and the upper end of the mover 5.

More specifically, as shown in FIG. 4, the corrugated portion 6 has a length L of the stator 1,
When the length is set to L / 4, L / 2, L × 3/4 and L, and the length of the mover 5 is set to L / 4, x, L, the stator 1 and the mover 5 are divided into four. The gap equation is as the first equation of the following equation 1.

[0008]

(Equation 1)

The above-described excitation winding 3 and output winding 4
As shown in FIG. 5, is composed of a well-known sinusoidal distribution winding disclosed in Japanese Patent Application Laid-Open No. 8-178611. Although the case of 12 slots will be described, the stator 1 in FIG. 1 is omitted and simplified to show a small number. Next, the SIN which forms the output winding 4 wound in each slot 2 at a one-slot pitch (a state in which windings are sequentially inserted into each slot without causing any slot skipping) with two phases different in phase from each other by L / 4. As shown in FIG. 5, the output winding 4B and the COS output winding 4A are distributed winding (the number of windings (amount) of the winding is also sinusoidal) such that the induced voltage distribution becomes a sinusoidal distribution. (Distributed). The winding of each of the output windings 4B and 4A has a number of turns proportional to SIN (COS) and its polarity (positive or reverse winding) depends on the SIN output voltage 4Ba and CIN.
The polarity is determined in consideration of the polarity of the exciting winding 3 so as to match the polarity of the OS output voltage 4Aa at each slot position.

That is, as shown in FIG.
Is a positive winding and the output windings 4B and 4A are positive windings,
When the exciting winding 3 is normal winding and the output windings 4B and 4A are reverse winding, a negative phase output is provided. When the exciting winding 3 is reverse winding and the output windings 4B and 4A are positive winding, a negative phase output is provided. Wire 3 is reverse winding and output winding 4
When the windings B and 4A are in reverse winding, the SIN output voltage 4Ba and the COS output voltage 4A
a so that each output winding 4 has a SIN shape and a COS shape.
Determine the polarity of B, 4A (forward or reverse).

Therefore, the output windings 4B and 4A for SIN and COS are provided with the above-mentioned well-known distributed windings (the number of windings and the amount thereof are also sinusoidally distributed) so that the induced voltage distribution becomes a sinusoidal distribution. ), The output windings 4B and 4A have the same phase output when the exciting winding 3 is in the positive winding and the output windings 4B and 4A are in the positive winding. , The output winding 4B,
The SIN output voltage and the COS output are set when the winding 4A is set to have the opposite phase output when the winding is positive, and when the exciting winding 3 is set to the reverse winding and the output windings 4B and 4A are set to have the same phase output when the windings 4A and 4A are reversed.
The output voltage becomes SIN and COS.

In the above-described configuration, when the movable element 5 is moved linearly in a state where a predetermined excitation signal is applied to the excitation winding 3 of the stator 1 and the excitation is performed, the output windings 4B and 4A output signals from FIG. Are output as SIN output voltage 4Ba and COS output voltage 4Aa, and tan ⁻¹ (S
By calculating (IN output / COS output), a linear position signal can be obtained. In this case, since the linear position signal is a function of the ratio of the two-phase output of the SIN output and the COS output, even if the gap between the stator 1 and the mover 5 changes variously, the ratio itself does not change. Also, the linear position signal does not change.

[0013]

Since the linear position detecting device according to the present invention is configured as described above, the following effects can be obtained. That is, on one surface of the mover facing the stator, a gap permeance with the stator is formed in a wave shape that changes in a sinusoidal manner with respect to the moving distance, and the configuration itself is linearly changed by a variable reluctance type resolver. Since the shape is expanded and linearized, signal detection is possible even if the gap between the stator and the mover is large. Also, since the mover is only the core, it is resistant to high-speed acceleration / deceleration, vibration and impact, and can perform good detection even in a bad environment.
Further, since the two-phase output voltage is equivalent to the resolver,
It can be converted into a digital signal by a known R / D converter.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a linear position detecting device according to the present invention.

FIG. 2 is a configuration diagram illustrating a winding of a stator of FIG. 1;

FIG. 3 is a right side view of FIG. 1;

FIG. 4 is an operation explanatory diagram of the configuration of FIG. 1;

FIG. 5 is a waveform diagram illustrating the operation of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 3 Excitation winding 4 Output winding 5 Mover 6 Waveform part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F063 AA02 BB03 BC10 CA29 DA01 DA05 DB04 DD06 EA02 GA22 GA33 GA36 GA47 GA69 KA02 LA19 2F077 AA42 FF03 FF11 FF34 FF39 JJ03 JJ06 JJ22 NN05 PP06 PP26 QQ03 RR03 TT05

Claims (1)

[Claims] 1. A mover (5) having a linear longitudinal shape, an exciting winding (3) and an n-phase output winding corresponding to one surface of the mover (5).
A stator (1) having (4) and the stator of the mover (5)
(1) having a waveform portion (6) formed on one surface facing the stator and having a gap permeance with the stator (1) that varies sinusoidally with respect to the moving distance, and exciting the excitation winding (3). A linear position detecting device, wherein a linear position signal is output from the output winding (4) by moving the mover (5) while a signal is being input.