KR20060107300A - Magnetic proximity switch - Google Patents

Abstract

An object of the present invention is to make it possible to reduce a change in the operation position with respect to a gap variation between a magnetic field detection unit and a magnetic field generation unit in a magnetic proximity switch.

The magnetic field generating unit 12 is composed of a plate-shaped magnetic metal body 13d and three permanent magnets 13a, 13b, and 13c having the same shape and material as adsorbed thereto. The three permanent magnets 13a to 13c are arranged in parallel at equal intervals along the sliding direction of the magnetic field generator 12 with the magnetic pole face of the copper pole (S pole) facing the magnetic field detector 11. The isomagnetic lines, in which the gap direction components of the magnetic force generated by each of the permanent magnets 13a to 13c are connected to each other, become a curve with little change in the operating position with respect to the gap direction variation at both ends.

Description

Magnetic Proximity Switch {MAGNETIC PROXIMITY SWITCH}

BRIEF DESCRIPTION OF THE DRAWINGS The whole block diagram of the magnetic proximity switch which is embodiment of this invention.

2 is a configuration diagram of a magnetic field generating unit of the first embodiment.

3 shows a magnetic field formed by the three permanent magnets of FIG.

4 is a view illustrating operating characteristics of a magnetic proximity switch including the magnetic field generator of FIG. 2.

Fig. 5 is a diagram showing another example of parallel arrangement of permanent magnets in the magnetic field generating portion of the first embodiment.

6 is a configuration diagram of a magnetic field generating unit of the second embodiment.

7 is an overall configuration diagram of a conventional magnetic proximity switch.

FIG. 8 is a view showing a magnetic field by the operating magnet of FIG. 7; FIG.

9 is an overall configuration diagram of another conventional magnetic proximity switch.

10 is a view showing a magnetic field by the permanent magnet of FIG.

FIG. 11 is a view showing operating characteristics of the magnetic proximity switch of FIG. 7; FIG.

FIG. 12 is a view showing operating characteristics of the magnetic proximity switch of FIG. 9; FIG.

<Explanation of symbols for main parts of drawing>

10: magnetic proximity switch

11: magnetic field detector

12: magnetic field generating unit

13a, 13b, 13c: permanent magnet

13d: magnetic metal body

13-1 to 13-5: permanent magnet

50: case

60: sealing material

The present invention relates to a magnetic proximity switch having a magnetic field generating portion and a magnetic field detecting portion for sliding relative to the magnetic field generating portion to detect a magnetic field generated from the magnetic field generating portion.

BACKGROUND ART Magnetic proximity switches used to control stops and the like on each floor of elevators in elevators are known.

[First Announcement]

7 is a diagram illustrating an example of a configuration of a conventional magnetic proximity switch.

The magnetic proximity switch 100 shown in the figure is composed of a magnetic detection element (magnetic field detection section) 101 and an operation magnet (magnetic field generation section) 103. The magnetism detecting element 101 is a magnetoresistive element or a hall element. The operation magnet 103 is a permanent magnet. The operation magnet 103 is disposed so that its magnetic pole surface faces the magnetic detection element 101. The operation magnet 103 slides in the direction (sliding direction) 107 with respect to the magnetic detection element 101 while maintaining the operation distance (gap 105) with respect to the magnetic detection element 101. FIG.

8 is a diagram illustrating a state of the magnetic force lines generated by the operation magnet 103.

In the figure, the Y axis represents a gap 105 which is a distance between the magnetic pole surface of the S pole of the operation magnet 103 and the end surface of the magnet detection element 101 side of the magnetic detection element 101, and the X axis represents the The position of the sliding direction 107 with respect to the magnetic detection element 101 of the working magnet 103 is shown. The X and Y axes are orthogonal.

As shown in FIG. 8, around the operation magnet 103, there is a magnetic force line 112 that curvely connects the N pole and the S pole of the operation magnet 103. Further, there is a curved isomagnetic line 113 (113a, 113b, 113c, etc.) obtained by plotting a place where the gap components of the magnetic force generated by the operation magnet 103 are the same.

Although the magnetic field lines 112 and the isomagnetic lines 113 actually exist below the X axis, they are omitted in FIG.

Second Announcement

In addition, as another known technique, the magnetic proximity switch shown in Fig. 9 is known.

The magnetic proximity switch 200 shown in the figure is composed of a reed switch 201 which is a magnetic field detection unit and an operation magnet (magnetic field generating unit) 203 which is a permanent magnet. The operation magnet 203 slides in a direction perpendicular to the longitudinal direction of the reed switch 201 (sliding direction) 207 while maintaining the operating distance (gap) 205 with respect to the reed switch 201.

10 is a diagram showing a state of the magnetic force lines generated by the operation magnet 203.

In the figure, the Y axis represents the gap 205 which is the distance between the operation magnet 203 and the reed switch 201, and the X axis represents the sliding direction 207 with respect to the reed switch 201 of the operation magnet 203. ) Distance.

As shown in FIG. 10, a curved magnetic force line 212 exists from the N pole to the S pole of the manipulation magnet 203 around the manipulation magnet 203. Further, there is a curved isomagnetic line 123 (123a, 123b, 123c, etc.) obtained by plotting the same magnetic force generated by the operation magnet. Although the isomagnetic lines 123 actually exist below the X axis, they are omitted in FIG.

[Third Announcement Example]

Moreover, as another well-known technique, the hall effect position sensor which comprised the magnetic field generating part which is an operation magnet, for example, a 1st permanent magnet and the 2nd and 3rd permanent magnets arrange | positioned by the same gap on both sides is known (patent document 1). Reference).

[Fourth Notice Example]

Moreover, what arrange | positioned three magnets on a back plate is known as a detector which detects the position of an elevator cabin. In this detector, a long magnet is disposed in the center on the back plate, and short magnets are disposed on both sides thereof (see Patent Document 2).

[Patent Document 1] Japanese Patent Application Laid-Open No. 7 (1995) -78538

[Patent Document 2] Japanese Patent Application Laid-Open No. 11 (1999) -246139

11 is a diagram showing the operating characteristics of the magnetic proximity switch 100 of the first known example.

The X axis in the figure is the relative position (distance) of the magnetic detection element 101 and the operation magnet 103, and the Y axis is the gap 105 between the magnetic detection element 101 and the operation magnet 103. The unit of X axis and Y axis is mm.

The solid line shown in FIG. 11 is the operating characteristic curve 131, and the broken line is the self return characteristic curve 132.

Here, the operating characteristic curve 131 is a curve connecting the points at which the magnetic detection element 101 operates (detecting the operating magnet 103), and the return characteristic curve 132 is the magnetic detection element 101. It is a curve connecting points returning from the operation state to the non-operation state.

As shown in the figure, the operation characteristic curve 131 widens in the sliding direction of the operation magnet 103 as the gap 105 increases, and as the gap 105 increases, the operation magnet ( It becomes a curve narrowing in the sliding direction of 103).

In the example shown in FIG. 11, the magnetic detection element 101 is operating when the relative position with the operation magnet 103 becomes 10 mm when the gap 105 is about 28 mm. Then, the magnetic detection element 101 operates in the region 134 where the relative position with the operation magnet 103 is about 7 mm to 10 mm in the range 133 where the gap 105 is 10 mm to 40 mm. (Switching).

12 is a view showing the operating characteristics of the magnetic proximity switch 200 of the second known example.

X-axis and Y-axis in the figure are the same as in FIG. The solid line in FIG. 12 is the operating characteristic curve 231 of the reed switch 201, and the broken line is the return characteristic curve 232. The operating characteristic curve 231 is a curve connecting the points at which the reed switch 201 is operated (turned on), and the return characteristic curve 232 is a state in which the reed switch 201 returns from the operating state to the inoperative state ( It is a curve connecting points that turn on and off.

The operating characteristic curve 231 and the return characteristic curve 232 of the reed switch 201 become substantially semicircular around the origin (0, 0) of the X-Y plane. In the example shown in FIG. 12, the reed switch 201 has a relative position between the reed switch 201 and the operation magnet 203 in the range 233 in which the gap 205 is 5 mm to 15 mm. It operates in the area | region 234 used as 21 mm.

In this way, the conventional magnetic proximity switch 100, 200 is a position where the detection unit (magnetic detection element 101, reed switch 201) switches operation with respect to the fluctuation of the gaps 105, 205 (hereafter, this position). The expression "operation position" fluctuates greatly. For this reason, when the conventional magnetic proximity switches 100 and 200 are used for sensors for controlling the stop positions of various devices (for example, elevators), when the gap between the detection unit and the operation magnet is changed due to the shaking of the device, The deviation of the stop position of a device became large, and the problem which caused the operation | movement of a device has arisen.

In addition, the Hall effect position sensor of the third known example solves the above problem, but since the magnetic field generating unit is composed of two kinds of magnets, it is not possible to realize inexpensive parts procurement due to the integration of members, resulting in an increase in product cost. There was this.

It is an object of the present invention to realize a magnetic proximity switch with a small change in the operating position against variations in the sliding direction of the magnetic field generator even when the gap between the magnetic field generator and the magnetic field detector is varied.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings.

1 is a configuration diagram showing an embodiment of the magnetic proximity switch of the present invention.

The magnetic proximity switch 10 shown in the figure includes a magnetic field detector 11 and a magnetic field generator 12.

The magnetic field detection unit 11 is a magnetic detection element such as a magnetoresistive element, a hall element or a reed switch. The magnetic field generator 12 is an operation magnet that slides in the sliding direction 17 relative to the magnetic field detector 11.

When the magnetic field generator 12 slides, the magnetic field generator 12 maintains a gap 15 (the distance in the vertical direction in FIG. 1 between the magnetic field detector 11 and the magnetic field generator 12) with respect to the magnetic field detector 11. While moving in the sliding direction (17). Here, in the present specification, when the magnetic field generating unit 12 slides with respect to the magnetic field detecting unit 11 in the sliding direction 17, the magnetic field detecting unit 11 and the magnetic field generating unit 12 in the sliding direction 17 are separated. The distance is defined as "relative position 16".

The magnetic field detector 11 operates when the relative position 16 approaches until the relative position 16 reaches a predetermined distance. This operation includes the on / off (switching) of the switch and the output of a detection signal or the like to an upper device (not shown) or an electric circuit (not shown) to which the switch is connected. In addition, the relative position 16 which the magnetic field detection part 11 operates is defined as an "operation position."

As will be described later, the magnetic proximity switch 10 of the present embodiment is configured so that the variation of the operation position becomes very small even if the gap 15 fluctuates greatly.

[First Embodiment]

FIG. 2 is a diagram illustrating an embodiment of the magnetic field generator 12 of FIG. 1.

The magnetic field generating unit 12 shown in FIG. 2 includes three permanent magnets 13 (13a, 13b, 13c), and a plate-shaped magnetic metal body 13d adsorbed by the magnetic force on these permanent magnets. The permanent magnets 13a, 13b, and 13c are all arranged such that the magnetic pole surface of the S pole faces the magnetic field detector 11. The plate-shaped magnetic metal body 13d is adsorbed on the N pole side magnetic pole surfaces of the permanent magnets 13a to 13c.

The plate-shaped magnetic metal body 13d is preferably a material having high magnetic permeability through which magnetic lines of force easily pass, high saturation magnetic flux density, and low magnetization characteristic hysteresis.

In addition, the plate-shaped magnetic metal body 13d induces the flow of magnetic field lines of the magnetic field generated by the permanent magnets 13a to 13c as intended by determining the shape appropriately in addition to fixing the permanent magnets 13a to 13c. At the same time, the shape of the isomagnetic lines is used to make the intended curve. For this reason, it is important for plate-shaped magnetic metal body 13d to have good workability. Therefore, as the plate-shaped magnetic metal body 13d, a workability is good and an inexpensive member is preferable. For example, iron (SPCC etc.). The steel sheet can be produced at low cost because both cutting and bending can be performed by pressing or the like.

In addition to the magnetic metal body, ferrimagnetic materials such as ferrite may be used for the installation members of the permanent magnets 13a to 13c. In this case, soft ferrite having a low hysteresis (for example, Mn-Zn based ferrite) is preferable. However, ferrite requires a mold for sintering, and because the manufacturing process is complicated, it is generally expensive compared with metal materials.

In the magnetic field generating unit 12 of FIG. 2, the three permanent magnets 13a to 13c are arranged in the same direction as the magnetic poles of adjacent permanent magnets. Therefore, the magnetic fluxes generated from the permanent magnets 13 are mutually different. Repulsion becomes strong. Further, since the magnetic metal body 13d has a higher magnetic permeability than air, the magnetic flux generated by the permanent magnets 13a to 13c tends to flow much more toward the magnetic metal body 13d having a higher magnetic permeability than air. Therefore, by appropriately determining the shape of the magnetic metal body 13d, the flow of magnetic lines connecting the S poles and the N poles of the permanent magnets 13a to 13c can be induced in the intended direction, and the permanent magnets It is possible to easily make the shape of the isomagnetic lines obtained by connecting the same points in the gap direction components in the lines of magnetic force of (13a to 13c) to the intended curves.

The magnetic field generating portion (operating magnet) 12 having the above-described configuration is configured to slide in the sliding direction 17 while maintaining the gap 15 with respect to the magnetic field detecting portion 11.

Here, the operation of the magnetic proximity switch 10 having the above configuration will be described.

1) When the magnetic field generating unit 12 is farther from the operating position of the magnetic field detecting unit 11, the magnetic field detecting unit 11 is in an inoperative state (for example, the output (detection signal) is turned off).

2) When the magnetic field generating unit 12 approaches the magnetic field detecting unit 11 and the magnetic field generating unit 12 reaches the operating position of the magnetic field detecting unit 11, the magnetic field generating unit 12 gives the magnetic field detecting unit 11 to the magnetic field detecting unit 11. The magnetic force is increased so that the magnetic field detector 11 operates (for example, the output (detection signal) is changed from off to on).

3) When the magnetic field generating unit 12 is far from the magnetic field detecting unit 11 and farther from the operation position of the magnetic field detecting unit 11, the magnetic force applied by the magnetic field generating unit 12 to the magnetic field detecting unit 11 decreases, and the magnetic field detecting unit is reduced. (11) returns to the inoperative state (for example, the output (detection signal) is turned on from off).

3 is a distribution diagram of the magnetic field generated by the three permanent magnets 13a to 13c of FIG. 2.

In FIG. 3, the X-axis is an axis which shows the component of the sliding direction 17, and the Y-axis is an axis which shows the component of the gap 15 direction (direction from the S pole of the permanent magnet 13 toward the magnetic field detection part 11).

As shown in the figure, in the space between the permanent magnets 13a to 13c and the magnetic field detector 11 (not shown in Fig. 3), the S pole and the N pole of the permanent magnets 13a to 13c are curved. There is a magnetic force line 21 that connects. The isomagnetic lines through which the magnetic force of the components in the gap 15 direction (Y-axis component) of the magnetic lines 21 generated from the permanent magnets are the same are the isomagnetic lines 22a, 22b, 22c, and 22d shown in solid lines in FIG. Is the same curve as Among these isomagnetic lines, the isomagnetic lines 22b and 22c have a small variation in the sliding direction 17 of the magnetic field generating unit 12 (change in the Y-axis component) with respect to the change in the gap 15 (change in the X-axis component). It becomes a curve.

In addition, although the magnetic field lines and the isomagnetic lines exist below the X axis, they are omitted in FIG.

4 is a diagram showing the operating characteristics of the magnetic proximity switching 10 of the present embodiment.

In the figure, the X axis represents the relative position 16 (unit is mm), and the Y axis represents the gap 15 (unit is mm). In addition, the curve of the solid line shown on both sides of the Y-axis is the operating characteristic curve 31, and the broken line is the return characteristic curve 32. As shown in FIG.

The operating characteristic curve 31 is a curve connecting the points at which the magnetic field detector 11 operates. The return characteristic curve 32 is a curve connecting the point where the magnetic field detector 11 returns.

As shown in Fig. 4, the operating characteristic curve 31 comes close to a vertical line in which the relative position 16 is parallel to the Y axis in the vicinity of 22 mm. For this reason, even if the relative position 16 produces the gap variation 33 of 10 to 40 mm in the vicinity of 22 mm, the variation in the operation position of the magnetic field detection unit 11 is very small. Therefore, when the relative position 16 of the magnetic field detection unit 11 and the magnetic field generation unit 12 is around 22 mm, even if the gap variation 33 is about 30 mm, the magnetic field detection unit 11 is the relative position 16. When the magnetic field generating unit 12 has been slid to a position of approximately 22 mm, it operates even if the gap variation 33 is large up to about 40 mm.

Therefore, the magnetic proximity switch 10 of this embodiment operates reliably even if the gap variation 33 is large at the time when the operation position of the magnetic field generating unit 12 is around 22 mm.

In the above embodiment, the magnetic pole surface of the N poles of the permanent magnets 13a to 13c is adsorbed to the plate-shaped magnetic metal body 13d, but the polarity is reversed to adsorb the magnetic pole surface of the S pole. good.

[Other arrangement of permanent magnets]

5 is a diagram illustrating another configuration example in which a plurality of permanent magnets are arranged in the magnetic field generating unit 12.

In the present invention, the plurality of permanent magnets are not necessarily arranged at equal intervals. However, it is preferable to arrange | position symmetrically. This is because, if a plurality of permanent magnets are not arranged symmetrically, the operating characteristic curve becomes asymmetrical, resulting in poor usability in practical use.

In the example shown in FIG. 5, five permanent magnets 13-1 to 13-5 are arranged in parallel in the sliding direction of the magnetic field generating unit 12. In the figure, the vertical broken line is the center line 40 in the parallel arrangement of the permanent magnets 13-1 to 13-5.

The permanent magnets 13-1 are arranged at the center, two permanent magnets 13-2 and 13-3 are disposed on the right side thereof, and two permanent magnets 13-4 and 13-5 on the left side thereof. This is arranged. Here, the distance between the center permanent magnet 13-1 and the permanent magnet 13-2 adjacent to the right side, and the distance between the permanent magnet 13-1 and the permanent magnet 13-4 adjacent to the left side are all " B ". Further, the distance between the permanent magnet 13-2 and the permanent magnet 13-3 adjacent to the right side and the distance between the permanent magnet 13-4 and the permanent magnet 13-5 adjacent to the left side are both "A". (B> A).

Thus, in the example shown in FIG. 5, five permanent magnets 13-1 to 13-5 are symmetrically arranged at boiling intervals.

Second Embodiment

6 is a configuration diagram showing another embodiment of the magnetic field generating unit 12.

The magnetic field generating unit 12 shown in the figure is composed of five permanent magnets 13-1 to 13-5, a case 50 and a sealing material 60. As shown in FIG.

The case 50 has five recesses into which the permanent magnets 13-1 to 13-5 are inserted, and the upper portions of the permanent magnets 13-1 to 13-5 are inserted in these recesses. The recesses are formed such that, for example, the permanent magnets 13-1 to 13-5 are arranged in parallel at the same interval as in FIG. The lower portions of the permanent magnets 13-1 to 13-5 inserted into the recesses of the case 50 are fixed by the sealing material 60.

Both the case 50 and the sealing material 60 need to be nonmagnetic material. This is to prevent the flow of magnetic flux generated from the permanent magnets 13-1 to 13-5. In addition, the case 50 and the sealing material 60 are preferably members having a specific permeability close to air. As the member of the case 50, plastic, aluminum (for example, aluminum die-cast), brass, etc. can be used, for example. As a member of the sealing material 60, resin, such as an epoxy resin, can be used, for example.

In the magnetic field generator of the present invention, it is also possible to arrange a plurality of permanent magnets in parallel in the sliding direction of the magnetic field generator 12. In this case, it is also possible to arrange these permanent magnets at boiling intervals without being symmetrical.

By arranging a plurality of permanent magnets in parallel in the sliding direction, it becomes possible to widen the operating range (the range surrounded by the right operating characteristic curve and left operating characteristic curve of the Y axis) of the magnetic field detector 11. In this case, the permanent magnet 13 is sparsely arranged at the center of the parallel arrangement. On both sides of this center portion, a plurality of permanent magnets 13 are arranged at both ends of the operation characteristic curve so that a curve (a curve close to a vertical line) in which the variation of the operation position with respect to the gap variation is small can be obtained.

By installing a plurality of permanent magnets in parallel in the sliding direction of the magnetic field generator 12 in such an arrangement pattern, the number of permanent magnets can be reduced and the manufacturing cost can be reduced.

As described above, in the present invention, a plurality of permanent magnets are used in the magnetic field generating unit 12 such that the isomagnetic lines of the magnetic field generated by the magnetic field generating unit 12 become curves in which the amount of change in the sliding direction at the time of the gap variation becomes small. It is configured to be arranged in parallel in the sliding direction.

As mentioned above, according to the magnetic proximity switch 10 of this embodiment, the fluctuation | variation of the operation position of the magnetic field detection part 11 when the gap fluctuation 33 fluctuates can be remarkably reduced compared with the past (FIG. 4 and , See FIG. 10 and FIG. 11). Therefore, when the operation signal (signal output at the operating position) of the magnetic proximity switch 10 of the present embodiment is used as the stop signal of the apparatus, even if the gap 15 fluctuates due to the swing of the apparatus, it always stops at the same position A signal can be output, and the stop position accuracy of the apparatus can be improved. In addition, since the magnetic proximity switch 10 of the present embodiment uses three permanent magnets 13a, 13b, and 13c having the same shape and material, integration of members can be achieved and inexpensive member procurement can be achieved.

The magnetic proximity switch 10 of the present embodiment can be applied, for example, to the alignment of the elevator floor and the floor of each floor of an elevator. In this case, for example, the magnetic field generating unit 12 is provided on the floor of each floor, and the magnetic field detecting unit 11 is installed in the elevator cabin of the elevator.

An elevator has low precision of the processing dimension and assembly dimension of a member, and the fluctuation | variation of the passage position of a hoisting chamber is large. For this reason, when a magnetic proximity switch is used for the control of the stop position of the elevator cabin, the gap variation of the magnetic field generating section and the magnetic field detecting section increases. However, since the magnetic proximity switch 10 operates (switching operation) at the same position irrespective of the fluctuation of the passing position of the hoisting chamber, the magnetic proximity switch 10 of the present embodiment has a floor surface of the elevator hoisting chamber and each floor. Can be easily and accurately performed. In addition, since the magnetic proximity switch 10 of the present embodiment can procure inexpensive members, the product cost can be lowered, thereby contributing to the cost reduction of the apparatus.

The present invention can be applied to position detection control of various devices and devices such as mechanical devices, electrical and electronic devices, automation devices, as well as elevators.

Claims (12)

A magnetic proximity switch comprising a magnetic field generating portion having a permanent magnet and a magnetic field detecting portion sliding in a predetermined direction relative to the magnetic field generating portion to detect the approach of the magnetic field generating portion, And the magnetic field generator comprises a plurality of permanent magnets installed in parallel in the sliding direction of the magnetic field generator so that the magnetic pole face of the same pole faces the magnetic field detector. The magnetic field generating unit of claim 1, wherein the magnetic field generating unit includes fixing means for fixing the plurality of permanent magnets to a predetermined position, and the plurality of permanent magnets have the magnetic pole surface opposite to the magnetic pole surface facing the magnetic field detection unit. A magnetic proximity switch opposing the means. The magnetic proximity switch of claim 2, wherein the fixing means is a magnetic material. 4. The magnetic proximity switch of claim 3, wherein the magnetic material is plate-shaped. The magnetic proximity switch according to claim 4, wherein the magnetic material is a material having good workability. The magnetic proximity switch of claim 3, wherein the magnetic body is a magnetic metal body. 7. The magnetic proximity switch according to claim 6, wherein the magnetic metal body has high magnetic permeability, high saturation magnetic flux density, and low magnetization hysteresis. The method of claim 2, wherein the fixing means is a case having a recess for fitting a portion of the plurality of permanent magnets, And a sealing material covering a portion of the plurality of permanent magnets not inserted into the case. 9. The magnetic proximity switch of claim 8, wherein the case and the seal are made of nonmagnetic material. The said plurality of permanent magnets are a component of the magnetic field which the said magnetic field generating part generate | occur | produces, and the component of the direction parallel to the gap between the said magnetic field generating part and the said magnetic field detection part perpendicular | vertical to the said sliding direction, The magnetic proximity switch obtained by connecting the same point in the gap direction components is arranged so that the amount of change in the sliding direction with respect to the gap fluctuation becomes small. The magnetic proximity switch of claim 10, wherein the plurality of permanent magnets are arranged to be symmetrical to each other. 12. The magnetic proximity switch of claim 11, wherein the plurality of permanent magnets are arranged so as to have a central portion coarse.

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