JPH0378616A - Position sensor - Google Patents

Abstract

PURPOSE:To detect the position of a moving body with high precision and to make it possible to cope with a large stroke by winding a signal detection coil of a sensor in inclination of a prescribed angle to an excitation coil. CONSTITUTION:A core member 2 being movable in parallel is inserted into an opening of a flat excitation coil 1 of which opposite-end openings are formed to be rectangular. A signal detection coil S is wound round on the outer periphery of the excitation coil 1 and the coil S is wound in inclination of a prescribed angle theta (e.g. about five degrees) to the excitation coil 1. When an alternating- current power is impressed on this excitation coil 1 and the core member 2 is moved, an output voltage as shown in the figure is detected at a position detection coil S in accordance with a position in the movement. A change signal V0 generated when the core member 2 is moved to the right or the left from a position 3' as a basis is detected, and a position in movement of a substance 100 to be measured can be detected therefrom in non-contact and with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a position detection sensor device, and more particularly to a position detection sensor device including an excitation coil and a moving core.

[Conventional technology]

Conventionally, cylindrical differential transformers (LVDTs) have been used as position detectors with relatively high accuracy.
Its linear movement stroke is short. - On the other hand, O in recent times
For linear drive devices used in A@ machines and FA equipment, there is a strong demand for not only improved positioning accuracy but also higher speeds and longer strokes.

For this reason, the inventor has proposed a movable flat type linear DC motor that can be positioned as shown in FIGS. 10(1) and 10(2).

In the conventional example shown in FIG. 10 (1), first, a DC drive voltage and an excitation AC voltage (for example, 5 (kHz)) are superimposed on the flat moving coil 51, which is a mover. DC current is applied to produce a driving force.

On the other hand, the AC component with a sufficiently high frequency excites the flat movable coil 51 without affecting the displacement. A pair of detection coils 52A, which have this flat moving coil 51 as a primary coil, are installed on a yoke 53 that is installed opposite to the flat moving coil 51, and are connected to each other with opposite polarities.

A differential transformer for position detection is constructed using 52B as a secondary coil. In reality, since there is displacement of the flat movable coil 51 in the vertical direction, errors can be reduced by using secondary detection coils at the upper and lower elbows. Figure 10 (1)
Reference numerals 54 and 54 indicate permanent magnets. Such a method makes it possible to perform highly accurate positioning using a small and relatively simple method.

FIG. 10(2) shows the relationship between the movable range of the flat movable coil 51 and the detected voltage in FIG. 10(1).

[Problem to be solved by the invention]

However, in such a conventional example, the entire flat movable coil must be moved together with the object to be positioned (not shown). For this reason, since the movable parts are relatively large, vibrations are likely to occur, and inertia forces are also applied, making it impossible to perform position control quickly.

[Purpose of the invention]

An object of the present invention is to improve the disadvantages of the conventional example, and in particular, to perform position detection that quickly and accurately positions an object to be controlled, and that can sufficiently cope with relatively large strokes. An object of the present invention is to provide a sensor device for

[Means to solve the problem]

The present invention includes a flat excitation coil having a rectangular opening, and a core member inserted so as to be able to move in parallel from one side of the rectangular opening of the excitation coil toward the other. . A signal detection coil is wound around the outer periphery of one of the openings of the excitation coil. Furthermore, this signal detection coil is wound with a predetermined inclination with respect to the winding of the excitation coil. This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

The embodiment shown in FIG. 1 includes a flat excitation coil 1 having rectangular openings at both ends, and a rectangular opening of the excitation coil 1 that is movable in parallel from one side to the other. It has a core member 2 inserted therethrough. A signal detection coil S is wound around the outer periphery of the excitation coil 1 and has the aforementioned rectangular closed portion as an opening. This signal detection coil S is wound around each winding of the excitation coil 1 with a predetermined width.

To explain this in more detail, in Fig. 1, the excitation coil 1
is wound around a hollow rectangular bobbin 10 made of plastic. This rectangular bobbin 10 is formed into a flat shape as a whole. The openings at both ends of the through-hole 10A formed in the central axis portion of the square bobbin 10 are also formed in a rectangular shape with a small width and a large length.

The excitation coil 1 is wound around the center of the outer periphery of the rectangular bobbin 10 as described above. This excitation coil 1
has width A and long side length B.

The length of the short side is C (however, B>>C).

The signal detection coil S is wound around the upper end of the excitation coil 1 in FIG. 1 at an angle of θ with respect to each coil of the excitation coil 1. This inclination θ is set to about 5 degrees in this embodiment.

In this embodiment, the signal detection coil S is arranged such that the center portion of each long side portion is located at the end PO3 of the width A in the center portion of the excitation coil 1 described above. Therefore, the right end portion of the signal detection coil S in FIG. 1 protrudes from the excitation coil 1 in the lower right direction.

The connection relationship between the signal detection coil S and the excitation coil 1 is shown in FIG. 3 (1). In FIG. 3(1), V (see FIG. 3(2)) indicates the voltage of the AC power supply applied to the excitation coil 1, and vo indicates the output of the signal detection coil S.

Further, the core member 2 is made of a boron material and is loosely inserted into the through hole 10A of the square bobbin 10. This core member 2 is disposed in a direction perpendicular to the excitation coil 1 described above. This core member 2 is the member to be measured 1.
When 00 moves in the direction of arrow R, it is equipped so that it can be moved in parallel as shown in (■) to (■) in FIG.

Next, the operation of the above embodiment will be explained.

First, as shown in Fig. 3 (1) and (2), the excitation coil l
Apply an AC power supply of voltage ■ to . In this case, the signal detection coil S is linked with the same magnetic flux as a whole. Therefore, when the core member 2 shown in FIG. 1 is not present, the output voltage is ■. The same signal as (2) applied to the excitation coil 1 is output as is.

Next, when the core member 2 is in the position indicated by the symbol ■ shown in FIG. ), and its output waveform is shown in (3) in the same figure. becomes.

Similarly, when the core member 2 is moved as indicated by symbols ■, ■, and ■ in FIG. 4 (1), the interlinkage magnetic flux of each signal detection coil S changes to .φ14.
φ, 5'', and the level of the output signal is also as shown in the figure (
3) As shown in “■,■,■.

■” changes. Therefore, in this embodiment, the first
When the core member 2 disposed in the excitation coil 1 shown in the figure or FIG. 2 moves in the left-right direction in the figure with reference to the position of the symbol ■, the signal detection coil S causes a change signal as shown in FIG. 4 (3). ■. Therefore, the linear reciprocating movement of the object to be measured 100 and its stop position can be detected with high precision without contact, and it can sufficiently cope with objects with relatively long movement strokes. I can do it.

FIG. 5 shows a modification of the two portions of the core member.

The one in FIG. 5 has the outer sides (
The core member 2 mentioned above (upper end surface side and lower end surface side in Fig. 5)
External core members 2A formed identically to the above are arranged in parallel, and both ends of each core member are covered with a non-magnetic material 1a.
It is connected by . The other configurations are the same as those in FIGS. 1 and 2 described above.

This has the advantage that the amount of magnetic flux that interlinks with the signal detection coil S increases overall, and the output level of the signal detection coil S increases accordingly.

Here, in this FIG. 5, the external core member 2A is
The excitation coil 1 may be configured to be provided only on the outside of one of the two long sides of the excitation coil 1. In this case, the level of the signal detected by the signal detection coil S is somewhat lower than that in FIG. 5, but experiments have shown that the sensitivity is significantly improved compared to the embodiment shown in FIG. has been confirmed.

FIG. 6 shows a plate 3 made of magnetic material on both sides of the signal detection coil S including the excitation coil 1.
It is equipped with 0. Other configurations are as described above.
This embodiment is the same as the embodiment shown in FIGS.

In this way, when the core member 2 moves and stops, the magnetic flux will always effectively interlink with the signal detection coil S, and therefore a high level signal can be detected without changing the size of the core member 2. It has the advantage of being able to be output.

Here, the plate material 30 shown in FIG. 6 can effectively increase the level of the output signal of the signal detection coil S even if it is installed only on one side.

Moreover, FIG. 7 shows another example of the method of winding the excitation coil 1.

The excitation coil 1 shown in FIG. 7 is constructed such that the number of turns gradually increases from the lower side to the upper side in the figure. Also, one end (8) of the signal detection coil S
0 portion) is located at the maximum number of turns of the excitation coil 1. The other configurations are the same as the embodiment shown in FIGS. 1 and 2 described above.

In this way, the linearity of the output of the signal detection coil S shown in FIG. 4 (3) can be further effectively improved, and the movement and stop of the core member 2 can be more clearly detected over a wide range. There is an advantage.

FIG. 8 shows another method of winding the signal detection coil S. The signal detection coil S shown in FIG. 8 is wound so that its center almost coincides with the center of the excitation coil I. In this case, both ends of the signal detection coil S protrude from the excitation coil 1. FIG. 9 shows changes in the measured value detected by the signal detection coil as the core member 2 moves in this case.

Therefore, in the case of FIG. 8, the signal level shown in FIG. 9 is recorded in advance in a memory, etc., and the core member 2
When measuring the position of the core member 2, by comparing the stored information as a reference, the movement and stopping position of the core member 2 can be easily measured in substantially the same way as in the case of FIG.

〔Effect of the invention〕

Since the present invention is configured and functions as described above, it is possible to detect the current position of the core member as it moves very easily and with high precision and without contact. As a result, it is possible to make the overall thickness extremely thin, and it is also possible to obtain a relatively large movement range of the core member. It is possible to provide an unprecedented position detection sensor device that can effectively respond to the displacement of a device with a large stroke.

[Brief explanation of drawings]

FIG. 1 is a partially sectional plan view showing the first embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 (1) shows the coil in FIG. A circuit diagram showing the connection relationship, Figure 3 (2) is a diagram showing the AC waveform applied to the excitation coil in Figure 3 (1), and Figures 4 (1), (2), and (3) are diagrams in Figure 1. 5 to 8 are explanatory diagrams showing other embodiments, FIG. 9 is a diagram showing the output of the signal detection coil in FIG. 8, and FIG. 10 (1) ( 2) are explanatory diagrams each showing a conventional example. ■... Excitation coil, 2... Core member, 30...
Plate material made of magnetic material, S,...Signal detection coil, θ...Irregular angle of the signal detection coil with respect to each winding of the excitation coil. X 1 0A 0 Figure 10 (1) (2)

Claims (10)

[Claims] (1) comprising a flat excitation coil having a rectangular opening, and a core member inserted so as to be able to move in parallel from one side of the rectangular opening of the excitation coil toward the other; Around the outer periphery of one of the openings of the excitation coil,
A position detection sensor device comprising a signal detection coil wound therein, the signal detection coil being wound at a predetermined inclination with respect to the winding of the excitation coil. (2) The position detection sensor device according to claim 1, wherein the signal detection coil has one short side of the rectangular coil protruding from the excitation coil. (3) A position detection sensor device characterized in that the signal detection coil has both ends of the rectangular coil protruding obliquely toward the respective openings of one and the other of the excitation coils. . (4) A position detection sensor device, wherein the excitation coil has a uniform number of turns per unit length in the direction along the central axis. (5) The excitation coil has a number of turns in the direction along the central axis from one opening side to the other opening side,
A position detection sensor device characterized in that the number of windings increases gradually. (6) A position detection sensor device, wherein the core member is loosely inserted in parallel to the central axis of the excitation coil. (7) The core member is connected via a non-magnetic member to an external core member that is formed substantially the same as the core member and is provided substantially parallel to the outer core member on the outside of the long side of the excitation coil. A position detection sensor device characterized by: (8) The core member is connected to first and second outer core members, which are formed identically to the core member and are provided approximately parallel to the outside of each long side of the excitation coil, through a non-magnetic member. 2. The position detection sensor device according to claim 1, wherein the position detection sensor device is connected to each other. (9) A position detection sensor device, characterized in that a plate made of a magnetic material is provided on the outer surface of one of the long sides of the excitation coil. (10) A position detection sensor device, characterized in that plates made of a magnetic material are provided on both outer surfaces of both sides of the excitation coil.