JP2008281152A - Brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake device not influenced by a flux generated from a brake coil and detecting a position of a movable iron core even in the state where the movable iron core stands still. <P>SOLUTION: This brake device furnished with a fixed iron core 2, the brake coil 5 wound around a circumference of the fixed iron core 2 and the movable iron core 3 attracted to the fixed iron core 2 by the flux generated from the brake coil 5, is furnished with a detection coil 6 to detect a distance between the fixed iron core 2 and the movable iron core 3 as a change of self inductance, in the fixed iron core 2, and the detection coil 6 is of a double ring type and constituted so that two coils are wound around in the opposite directions to each other and connected to each other in series and the interlinkage number of the number of turns and an area with the flux generated from the brake coil 5 becomes roughly zero. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic brake device for an elevator hoisting machine, for example.

  In the conventional brake device, in order to monitor the open / close state of the brake, the stroke of the movable iron core is enlarged by a lever, and the micro switch is opened / closed (for example, see Patent Document 1).

  In addition, in order to measure the size of the air gap between the fixed iron core and the movable iron core, a change in magnetic flux generated by the brake coil is detected by the search coil, and the detection signal is signal-processed to obtain a desired amount. Yes (see, for example, Patent Document 2).

  The conventional brake device configured as described above can detect the open / close state of the movable iron core or the size of the air gap by mechanical or electromagnetic means.

Japanese Patent Laying-Open No. 2005-194076 (page 5, FIG. 1) Japanese Patent No. 2004-137060 (8th page, FIG. 1)

  In the brake device as described in Patent Document 1, there is a problem that in addition to the cost of the microswitch itself, a certain time is required for assembling and adjusting the lever and the microswitch, and the manufacturing cost is increased.

  Further, in a thin hoist used for a machine room-less elevator or the like, there is a problem that it is difficult to design a space for mounting a lever or a micro switch.

  On the other hand, in the brake device as in Patent Document 2, since the change of magnetic flux occurs only when the movable iron core moves, the position of the movable iron core cannot be detected when the movable iron core is stationary. There is a problem that it cannot be used as a means for monitoring the open / closed state of.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a brake device that can detect the position of the movable iron core by a low-cost and space-saving means.

The brake device according to the present invention includes a fixed iron core, a brake coil wound around the fixed iron core, and a movable iron core attracted to the fixed iron core by magnetic flux generated by the brake coil. ,
The fixed iron core is provided with a detection coil that detects the distance between the fixed iron core and the movable iron core as a change in self-inductance,
The detection coil is configured such that the number of linkages with the magnetic flux generated by the brake coil is substantially zero.

  According to the brake device of the present invention, the position of the movable iron core can be detected even when the movable iron core is stationary, and it is not affected by the magnetic flux generated by the brake coil.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a first embodiment of a brake device according to the present invention, FIG. 2 is a plan view (a) and a front view (b) of FIG. 1, and FIG. 4 is a cross-sectional view taken along the line II-II in FIG. 2, and FIG. 5 is a perspective view showing details of the detection coil in FIG.

  As shown in the figure, the brake device 1 includes a fixed iron core 2, a movable iron core 3, repulsive springs 4a and 4b, a brake coil 5, a detection coil 6, and an excitation power source (not shown).

  The fixed iron core 2 has a substantially E-shape, and has an inner pole 7 projecting from the center, two outer poles 8a and 8b projecting on both sides of the inner pole 7, and an inner pole 7 And a yoke portion 9 that connects the outer poles 8a and 8b. On the other hand, the movable iron core 3 has a substantially rectangular parallelepiped shape, and is configured such that one end face thereof is in contact with and separated from each end face of the inner pole 7 and the outer poles 8a and 8b of the fixed iron core 2.

  Two cylindrical concave portions are provided on the plane of the inner pole 7, and repulsion springs 4a and 4b are disposed therein. A brake coil 5 is wound around the side surface of the inner pole 7. Further, a very shallow recess having a depth of about 0.1 mm is provided in the center of the plane of the inner pole 7, and the detection coil 6 is disposed in the recess.

As shown in FIG. 5, the detection coil 6 is formed on a flexible printed circuit board (FPC), and the conductor portion of the detection coil 6 formed on the printed circuit board 6c has a double ring shape. It is divided into a first partial coil 6a at the outer peripheral portion and a second partial coil 6b at the inner peripheral portion. The winding directions of the two partial coils 6a and 6b are opposite to each other, and both are connected in series. In addition, the number of turns N ₁ and N ₂ and the areas S ₁ and S ₂ of the two partial coils 6a and 6b are determined by the respective interlinkage magnetic fluxes Ψ ₁ and Ψ ₂ generated by the magnetic flux (magnetic flux density B) generated by the brake coil 5 It is configured to be substantially equal to each other, that is, the following (Formula 1) is established.

Ψ ₁ ≈Ψ ₂ (Formula 1)
Here, ψ ₁ = N ₁ ∫S ₁ Bda, ψ ₂ = N ₂ ∫S ₂ Bda

6 and 7 are cross-sectional views for explaining the operation of the brake device according to the first embodiment.
The brake coil 5 is excited by a DC power source. When the brake coil 5 is excited, as shown in FIG. 6, the brake magnetic flux 11 is changed in the order of “inner pole 7 → air gap 10 → movable iron core 3 → air gap 10 → outer poles 8a, 8b → inner pole 7”. It flows in a series of magnetic circuits. The movable iron core 3 is attracted to the fixed iron core 2 by the electromagnetic force generated at this time. On the contrary, when the excitation of the brake coil 5 is released, the brake magnetic flux 11 and the electromagnetic force disappear, and the movable iron core 3 is separated from the fixed iron core 2 by the action of the repulsive springs 4a and 4b.

  On the other hand, the detection coil 6 is excited by an AC power source. When the detection coil 6 is excited, as shown in FIG. 7, the detection magnetic flux 12 is “inside the second partial coil 6b → the air gap 10 → the movable core 3 → the air gap 10 → the first partial coil 6a and the second part. The magnetic circuit alternates and flows in the order of “the gap of the coil 6b → the inner pole 7 → the second partial coil 6b”. The size of the generated detection magnetic flux 12 is inversely proportional to the size of the air gap 10 when the current flowing through the detection coil 6 is constant. Therefore, the self-inductance of the detection coil 6 decreases when the air gap 10 is large, and increases when the air gap 10 is small. The size of the air gap 10 can be detected by detecting the impedance change due to this self-inductance change using a bridge circuit or the like.

Note that the detection magnetic flux 12 generated by the detection coil 6 is much smaller than the brake magnetic flux 11 generated by the brake coil 5, and thus does not affect the operation of the movable iron core 3. On the contrary, the linkage flux of the detection coil 6 generated by the brake flux 11 generated by the brake coil 5 cancels the linkage flux Ψ ₁ of the first partial coil 6 a and the linkage flux Ψ ₂ of the second partial coil 6 b. To meet, it becomes almost zero. Therefore, the detection coil 6 is not affected by the change in the brake magnetic flux 5.

As described above, the brake device 1 according to the first embodiment has the following features. First, the installation space can be reduced by using a flexible printed wiring board for the detection coil 6.
Secondly, the position of the movable core 3 can be detected even when the movable core 3 is stationary by exciting the detection coil 6 independently of the brake coil 5 with an AC power supply.
Thirdly, the position of the movable iron core 3 can be detected without being affected by the brake magnetic flux 5 by appropriately setting the number of turns and the area of the first partial coil 6a and the second partial coil 6b.

Embodiment 2. FIG.
FIG. 8 is a cross-sectional view showing a second embodiment of the brake device according to the present invention, and FIG. 9 is a cross-sectional view for explaining the operation of the brake device in the second embodiment.

  As shown in FIG. 8, the detection coil 6 is not a double ring, but includes two partial coils 6 a and 6 b that are independent at different positions.

  In the second embodiment, the partial coils 6a and 6b having the same number of turns and the same area are arranged at the left and right symmetrical positions and connected in series. The direction of connection is such that the detected magnetic fluxes generated by the partial coils 6a and 6b are opposite to each other.

Therefore, as shown in FIG. 9, the detection magnetic flux 12 generated by the detection coil 6 is “first partial coil 6a → air gap 10 → movable core 3 → air gap 10 → second partial coil 6b → inner pole 7 → As in the first embodiment, the linkage magnetic flux of the detection coil 6 generated by the brake magnetic flux 11 generated by the brake coil 5 flows through a magnetic circuit connected in the order of the yoke portion 9 → the inner pole 7 → the first partial coil 6a ”. since the flux linkage of the first partial coils 6a [psi ₁ and the flux linkage [psi ₂ of the second part coil 6b cancel each other, it becomes substantially zero.

  According to the second embodiment, since the same partial coil can be used, the design of the detection coil 6 is facilitated, and the degree of freedom of the mounting location is increased.

1 is a perspective view showing a first embodiment of a brake device according to the present invention. It is the top view (a) and front view of FIG. It is II sectional drawing of FIG. It is II-II sectional drawing of FIG. It is a perspective view which shows the detail of the detection coil in FIG. It is sectional drawing for demonstrating an effect | action of the brake device in this Embodiment 1. FIG. It is sectional drawing for demonstrating an effect | action of the brake device in this Embodiment 1. FIG. It is sectional drawing which shows Embodiment 2 of the brake device which concerns on this invention. It is sectional drawing for demonstrating the effect | action of the brake device in this Embodiment 2. FIG.

Explanation of symbols

1 brake device, 2 fixed iron core, 3 movable iron core, 4a, 4b repulsion spring,
5 Brake coil, 6 detection coil, 6a, 6b partial coil, 7 inner pole,
8a, 8b outer pole, 9 yoke part, 10 air gap, 11 brake magnetic flux,
12 Detection magnetic flux.

Claims (4)

In a brake device comprising a fixed iron core, a brake coil wound around the fixed iron core, and a movable iron core attracted to the fixed iron core by a magnetic flux generated by the brake coil,
The fixed iron core is provided with a detection coil that detects the distance between the fixed iron core and the movable iron core as a change in self-inductance,
The brake device, wherein the detection coil is configured so that the number of linkages with the magnetic flux generated by the brake coil is substantially zero. The detection coil is composed of two partial coils having a substantially double ring shape, and the two partial coils have a number of turns and an area so that the number of linkages with the magnetic flux generated by the brake coil is approximately equal to each other. 2. The brake device according to claim 1, wherein the two partial coils are connected in such a direction that the sum of the number of linkages is substantially zero. The detection coil is composed of two partial coils having the same shape, the two partial coils are arranged at positions symmetrical to the magnetic flux generated by the brake coil, and the two partial coils are 2. The brake device according to claim 1, wherein the brake device is wired in such a direction that the sum of the number of interlinkages is substantially zero. 4. The brake device according to claim 1, wherein the detection coil is formed on a flexible printed wiring board.

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