JPS61172011A - Displacement detector - Google Patents

Abstract

PURPOSE:To attempt to obtain a large output regardless of reeled width of coil, by positioning the operation starting point of a magnetic body in the outside positioned end surface of the coil. CONSTITUTION:A DC power source is applied to the primary side coil 7 of a differential transformer 5, the initially induced voltage produced in the secondary side coil 8 is something around 0.2V. Air pressure from a pressure inlet port 22, causes floating upward of the pressure receiving surface 10 of a diaphragm 9 to push up uniformly each surface of a circular disc body 11 against a pressure adjusting spring 18. Thus, a magnetic body 17, by keeping a uniform clearance with the inside periphery of the transformer 5, slides from the outside of the end surface of the secondary side coil 8 to the inside. At this moment, by positioning the operation starting point of the magnetic body 17 on the outside of the coil end surface, a longer stroke length of the magnetic body 17 and more conspicuous change of reactance can be permitted without increasing reeled width of the coil. And a spring makes elongation and construction inside the transformer 5 and its deformation increases densenesses of steel wires and magnetic fluxes and produces voltage produced in such a way that they are produced as gradual increments to the output voltage of individual magnetic body 17, and displacement of the magnetic body 17 produced the induced electric voltage in the order of 4.5V facilitating thus, judgement process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a displacement detector having a coil and a diaphragm, and in particular, the attachment of the core is defined in terms of position.

[Conventional technology]

Currently, there are many examples of using displacement detectors equipped with a coil and diaphragm for controlling electronic equipment, etc., but the conventional example is
Many of them, such as Japanese Patent Laid-Open No. 50-17656, show the operating principle, but none specify the details of the component configuration.

The present invention has been made in view of this point, and at the same time specifies the overall component configuration and stipulates the attachment of the magnetic body (core) that influences the overall thickness of the JI product.

[Problem that the invention seeks to solve]

Magnetic flux is generated around the coil, and when a magnetic object approaches, the magnetic flux increases and the actance of the coil changes. Normally, the magnetic material is moved within the entire length of the coil, but in order to increase the output, the stroke of the magnetic material is increased. As a result, the weight of the coil 9 increases, and the overall size of the product increases when considering the installation of the coil, etc. 6 The present invention uses the area around the coil that is affected by the magnetic flux, that is, the outside of the end face of the coil as the starting point of the magnetic material movement. The aim is to obtain large output regardless of the winding weight of the coil.

[Means for solving problems]

The present invention focuses on the fact that the magnetic flux reaches not only the inner surface of the coil but also the periphery of the coil, and the starting point of the magnetic body is located outside the end face of the coil, and from that position it gradually approaches the coil, and finally It is inserted into the coil.

[Effect]

As a result, the stroke of the magnetic body can be increased without increasing the winding weight of the coil, and the output, which is difficult to detect, can also be increased.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIGS. 1, 2, and 3.

This will be explained with reference to FIGS. 4, 5, and 6.

1 is a base made of a rigid body made of ABS resin or polyacetal resin, and has a cylindrical part 2 having a fitting protrusion at the center of the outside, and primary coils 7 and 2 in which a polyurethane-coated electric wire or the like is wound around the cylindrical part 2. A bobbin 6, which is a rigid body made of ABS resin or polyacetal resin and has a next coil 8, is removably inserted and fixed by the fitting protrusion 3.

The bobbin 6 has a winding drum outer diameter of φ17 and is wound 2200 times (resistance value 630 to 650Ω) on both the primary and secondary sides, with the secondary coil 8 being wound around the magnetic body and the primary coil 7 being wound outside. The frequency of 50 to 70 is applied to the primary coil.
A kHz square wave direct current is applied. Magnetic material 1
7 is attached so as to slide inside the secondary coil 8.

Further, inside the base 1, there is a thin film diaphragm 9 having a pressure receiving surface 10 and a base part 19 formed of rubber or cloth-filled rubber, a disc body 12 that comes into contact with the pressure receiving surface 10, and a screw perpendicular to the diaphragm 9. A rigid sliding body 11 is provided, which is made of a polyacetal resin containing oil or paraffin, and has a hollow shaft 13, a circumferential wall with a fitting protrusion, and a circumferential groove 15. The buoyant force of the diaphragm 9 is uniformly received on each surface of the diaphragm 9 so that the hollow shaft portion 13 is always held perpendicular to the center portion, and the bearing port 4 is slid. In the hollow shaft portion 13 of the sliding body 11, an adjustment screw 20 made of a rigid body made of polyacetal resin has one end in contact with the base portion 19, and the adjustment screw 2
By turning 0, the mover 11 and the magnetic body 17 are engaged so as to be finely adjusted up and down using the base portion 19 as a reference point. Further, in the circumferential wall portion 14, a cut groove 25 and a guide protrusion 26 are aligned so that a magnetic body 17 made of a circular steel plate made of permalloy or ferromagnetic material can be positioned in a fixed direction. Inserted and fixed. Further, in the circumferential groove portion 15, a pressure adjustment spring 18 that adjusts the amount of movement of the sliding body 11 against the buoyant force of the diaphragm 9 biases the sliding body 11 with the inner surface around the bearing port 4 of the base 1 as a starting point, It is located inside the magnetic body 17 and is attached so that it can expand and contract at the inner circumference of the differential transformer 5 at all times.

A rigid upper lid 21 made of ABS resin or polyacetal resin is welded and fixed to the base 1 in such a manner that an air chamber 29 is formed between it and the diaphragm 9. It has a pressure receiving port 22 to which a pressure transmission tube 24 is connected.

Further, a fixing protrusion 23 for preventing the diaphragm 9 from deflecting is provided near the inner surface pressure receiving port 22.

The protective frame 27 is detachably inserted and fixed between the fitting protrusion 28 and the end face of the bobbin 6 so as to cover the differential transformer 5 to prevent dust and water droplets.

FIG. 7 shows the installation of the differential transformer 5, and will be introduced as the same example as above. The basic configuration is that a cylindrical portion 2a is provided at the center of the outside of the base 1a, and a differential transformer 5 is removably inserted and fixed into this cylindrical portion 2a.

Next, the operation will be explained.

When a 5V square wave DC power supply with a frequency of 50 to 70 KHz is applied to the primary coil 7 of the differential transformer 5 through the drive circuit shown in FIG. 5, the initial induced voltage generated in the secondary coil 8 is 0. It is about .2v. When air is forced into the pressure receiving port 22, the pressure receiving surface 10 of the diaphragm 9 floats up, and uniformly pushes up each surface of the disk body 11 against the pressure adjustment spring 18.

Therefore, the magnetic body 17 slides from the outside to the inside of the end face of the secondary coil 8 on the output side, that is, while maintaining a uniform gap with the inner peripheral portion of the differential transformer 5 without being oblique. As the magnetic body 17 slides, it directly acts on the lines of magnetic force generated in the secondary coil 8, so as shown in FIG. Large output voltage (
(thick line).

The pressure adjustment spring 18 expands and contracts within the differential transformer 5, and when it bends, it increases the density of the steel wire, increases the density of the magnetic lines of force,
As shown by the broken line in FIG. 6, a voltage that is gradually added to the output voltage of the magnetic body 17 alone (thick line) is output, and when the magnetic body 17 moves to the position (approximately 4+aa+) as shown in FIG. 3, the induced voltage is about 4.5v. That is, magnetic material 1
When 7 moves by 4 cm, the voltage change amount is 4.5V, which is a large value, and it is easy to perform the discrimination process using the circuit shown in FIG.

〔Effect of the invention〕

According to the present invention, by locating the starting point of the magnetic body outside the end face of the coil, the stroke of the magnetic body can be taken sufficiently without increasing the winding weight of the coil, and the change in actance of the coil that affects detection performance is also large. can do. or,
Since the winding weight of the coil is small, the overall product can be made smaller.

[Brief explanation of drawings]

Figure 1 is a plan view showing one embodiment of the present invention, Figures 2 and 3 are
The figure is a front sectional view showing one embodiment of the present invention. FIG. 4 is an exploded perspective view showing one embodiment of the present invention, FIG. 5 is a drive circuit diagram of one embodiment of the present invention, and FIG. 6 is a characteristic S of one embodiment of the present invention. 1... Base, 2... Cylindrical part, 5... Differential transformer,
7...Primary side coil, 8...Secondary side coil, 9...
-Diaphragm, 11...Sliding body, 12...Disc body, 13...Hollow shaft. 17...Magnetic material, 18...Pressure adjustment spring, 20...
・Adjustment fraud cap No. 3 Mouth corner irregularity Figure 9 Mine Suno/z J 4-! □Salary change 4t (So Mn

Claims (1)

[Claims] 1. A displacement detector comprising a coil and a diaphragm, characterized in that the end face of the magnetic body (core) is located outside the end face of the coil winding.