JP4153294B2 - Proximity switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a proximity switch that detects that a magnetic body is approaching.
[0002]
[Prior art]
Conventionally, a proximity switch including a bias magnetic field generating magnet (hereinafter referred to as a bias magnet) and a magnetic sensor for detecting a magnetic flux from the magnet is known. With this configuration, a change in the amount of magnetic flux applied to the magnetic sensor of the bias magnet (ie, magnetic flux density) when the magnetic body approaches or moves away from the proximity switch is detected, and the position of the magnetic body with respect to the proximity switch is detected. The
[0003]
When the proximity switch having the above configuration is used as, for example, a pedal switch, the proximity switch is fixedly disposed, and the magnetic body can be moved together with the pedal. The magnetic body is configured to detect that the proximity switch is turned off in proximity to the proximity switch when the pedal is at a rest position, and to detect that the proximity switch is turned on when the pedal is depressed to operate the magnetic body ( For example, see Patent Document 1.) Such a proximity switch is preferably used when certainty and quickness are required for switching the switch.
[0004]
[Patent Document 1]
JP-A-9-17299 ("0008", FIG. 1)
[0005]
[Problems to be solved by the invention]
However, since the proximity switch and the member on which the magnetic body is provided are separate members, an assembly error between them tends to occur. For example, when the magnetic body is close to the proximity switch at a position away from the assumed predetermined position, the amount of magnetic flux induced in the magnetic body decreases, and conversely, the amount of magnetic flux applied to the magnetic sensor is reduced. To increase. For this reason, in proximity switches configured such that a magnetic body approaches a magnetic sensor, it is required to eliminate variations in magnetic flux applied to the magnetic sensor regardless of assembly errors.
[0006]
The present invention has been made in view of the above problems, and provides a proximity switch that prevents variations in magnetic flux applied to a magnetic sensor by setting a predetermined interval between a magnetic body and a bias magnet regardless of assembly errors. The purpose is to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 includes a bias magnet and a magnetic sensor for detecting a change in the amount of magnetic flux applied from the bias magnet in a case formed of a non-magnetic material. The proximity switch includes a guide member that positions the magnetic body so as to face the bias magnet at a predetermined interval, and a regulating member that positions the magnetic body in contact with the guide member. A guide groove and an accommodating portion are formed, and the guide groove is formed along the X axis, the Y axis, and the Z axis, which are three axes orthogonal to each other, and the Y axis direction and the anti-Y axis direction are Opened, one end side in the Z-axis direction is connected, the other end side in the Z-axis direction is opened, the guide member and the regulating member are formed on both sides in the X-axis direction of the guide groove, Is Wherein the scan magnet and said magnetic sensor is arranged.
[0008]
According to a second aspect of the present invention, in the first aspect, the guide member has a first guide surface for slidingly contacting the magnetic body, and the restricting member is disposed opposite to the first guide surface. It has two guide surfaces.
[0009]
Furthermore, the invention described in claim 3 is characterized in that in claim 1 or 2, the magnetic member has a guide surface for guiding the magnetic body to the guide member.
According to a fourth aspect of the present invention, in any one of the first to third aspects, the connector is connected to the outside of the case and output from the magnetic sensor. And a processing circuit for processing the signal .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a proximity switch and a pedal switch using the proximity switch will be described with reference to FIGS. 1 to 6.
[0012]
〔Proximity switch〕
First, the proximity switch will be described.
As shown in FIGS. 1A and 1B, the proximity switch 1 has a bias magnet 2 and a magnetic sensor 3 fixed in a case 6 formed of a nonmagnetic material such as synthetic resin, and a connector. 5 and a processing circuit 4 are arranged.
[0013]
In the following description, as shown in FIG. 1A, the right direction in the drawing is referred to as the X-axis direction, and the downward direction in the drawing orthogonal to the X-axis direction is referred to as the Y-axis direction. Moreover, as shown in FIG.1 (b), the downward direction in the figure which is a longitudinal direction of case 6 is called Z-axis direction.
[0014]
As shown in FIG. 2, the case 6 includes a guide groove 7 that is formed in a cylindrical shape, is offset from the axial center and is cut in the longitudinal direction, and a storage portion 9 that is formed in a semicircular cross section. . The guide groove 7 is opened in the Y-axis direction and the anti-Y-axis direction, one end side in the Z-axis direction is connected, and the other end side is open. The accommodating portion 9 is formed so as to penetrate in the Z-axis direction.
[0015]
For this reason, the case 6 is formed with a partition plate 6a as a guide member at a substantially central portion in the X-axis direction, and a regulation portion 6b as a regulation member is formed on the right side in FIG. And on the inner side surface of the guide groove 7, the surface on the side of the partition plate 6a is a first guide surface 8a. The surface on the regulating portion 6b side is a second guide surface 8b disposed in parallel to face the first guide surface 8a. Further, as shown in FIG. 1B, an inclined surface 8c as a guide surface is formed at the end of the guide groove 7 of the first guide surface 8a on the open side in the Z-axis direction. Similarly, in the guide groove 7 of the second guide surface 8b, an inclined surface 8d as a guide surface is formed at the end portion on the open side in the Z-axis direction.
[0016]
The bias magnet 2 is a square pole-shaped bar magnet, and is fixed to the case 6 with the longitudinal direction as the Z-axis direction, the same line in the Z-axis direction, with the S pole on the upper side and the N pole on the lower side. That is, the bias magnet 2 and the partition plate 6a of the case 6 are disposed to face each other in parallel with the Z-axis direction. And it has the magnetic flux line (it shows with a dotted line in the figure) which goes to a south pole from a north pole. As described above, the bias magnet 2 is disposed in the housing portion 9 of the case 6, so that the guide groove 7 is a region where the magnetic field of the bias magnet 2 is formed.
[0017]
The magnetic sensor 3 is disposed and fixed between the bias magnet 2 and the partition plate 6a. The magnetic sensor 3 detects a bias magnetic flux generated by the bias magnet 2 and outputs a signal. The magnetic sensor 3 may be provided at any position as long as the magnetic flux from the bias magnet 2 can be detected. 2 is preferably provided at a position where the amount of magnetic flux from 2 changes significantly. In the present embodiment, it is preferable to be provided at a position close to the bias magnet 2 between the bias magnet 2 and the partition plate 6a. The magnetic sensor 3 includes, for example, a Hall element, an MR element, a GMR element, and the like.
[0018]
The processing circuit 4 includes an amplification circuit that amplifies the detection signal output from the magnetic sensor 3, a comparison circuit that determines whether the amplified detection signal is equal to or less than a threshold value, and outputs a determination signal. . The connector 5 connects the outside of the proximity switch 1 and outputs a determination signal determined by the processing circuit 4 to an external control circuit or the like.
[0019]
Further, a magnetic body 20 is disposed so as to be accessible to the proximity switch 1 described above. The magnetic body 20 has a flat plate shape in the YZ plane direction, and has a flat plate surface area sufficiently larger than the YZ direction cross-sectional area of the case 6 of the proximity switch 1. The thickness of the magnetic body 20 in the X-axis direction is substantially the same as the width of the guide groove 7 in the X-axis direction. Then, it is restricted in the X-axis direction and can be moved in the Z-axis direction and the Y-axis direction, and can be inserted into the guide groove 7 from the opposite Z-axis direction.
[0020]
Next, the operation of the proximity switch 1 will be described.
In the above configuration, the magnetic body 20 is inserted into the guide groove 7 of the case 6 of the proximity switch 1 so as to enter the magnetic field of the bias magnet 2 with respect to the proximity switch 1 (see FIG. 3). This state is called a proximity state. At this time, the magnetic body 20 is suitably guided into the guide groove 7 by the inclined surfaces 8c and 8d.
[0021]
The magnetic body 20 induces the magnetic flux of the bias magnet 2. Therefore, the amount of magnetic flux of the bias magnet 2 detected by the magnetic sensor 3 is the amount of magnetic flux induced by the magnetic body 20 reduced. That is, when the magnetic body 20 is separated from the proximity switch 1, a considerable amount of magnetic flux from the bias magnet 2 is applied to the magnetic sensor 3, but when the magnetic body 20 is close to the bias magnet 2, the magnetic flux is A large number of closed loops of magnetic flux are formed in the magnetic body 20 by being absorbed by the magnetic body 20. As a result, the amount of magnetic flux applied to the magnetic sensor 3 decreases.
[0022]
At this time, the magnetic body 20 is disposed to face the bias magnet 2 at a predetermined interval by the partition plate 6 a of the case 6. The magnetic body 20 is positioned by contacting the partition plate 6a by the restricting portion 6b. The magnetic body 20 is slidably contacted with the first guide surface 8a of the partition plate 6a, and the position in the X-axis direction is restrained by the second guide surface 8b of the restricting portion 6b.
[0023]
Therefore, in the proximity state of the proximity switch 1 and the magnetic body 20, the amount of magnetic flux from the bias magnet 2 with respect to the magnetic sensor 3 is always constant.
For example, let us consider a case where the proximity switch is not configured to dispose the magnetic body facing the bias magnet at a predetermined interval. In that case, due to the assembly error between the proximity switch and the magnetic body, the distance between the bias magnet and the magnetic body tends to fluctuate in the proximity state of the proximity switch and the magnetic body. Then, when the interval between the magnetic bodies with respect to the bias magnet is narrow, the magnetic flux is absorbed by the magnetic body and more closed loops of the magnetic flux are formed in the magnetic body than when the interval is wide. As a result, the amount of magnetic flux applied to the magnetic sensor decreases.
[0024]
On the other hand, when the interval is wide, the magnetic flux is not so much absorbed by the magnetic material, and the amount of magnetic flux applied to the magnetic sensor is not so reduced. As described above, when an assembly error between the proximity switch and the magnetic material occurs, the amount of magnetic flux detected by the magnetic sensor is significantly changed and varies.
[0025]
When the magnetic body 20 moves away from the proximity switch 1 in the Z-axis direction (separated state) from the proximity state, the magnetic flux of the bias magnet 2 is influenced by the magnetic body 20 as shown in FIG. Not receive. Therefore, in this separated state, the amount of magnetic flux from the bias magnet 2 with respect to the magnetic sensor 3 is less than the amount of magnetic flux induced by the magnetic body 20, so that the magnetic body 20 is inserted into the guide groove 7. A large amount of magnetic flux from the bias magnet 2 is applied to the magnetic sensor 3.
[0026]
4, the magnetic body 20 in the proximity state with respect to the proximity switch 1 according to the present embodiment, a change in output level when moving gradually anti Z-axis direction from the point of time T _1. In FIG. 4, the horizontal axis represents time, and the vertical axis represents the output level of the proximity switch 1 (unit is V).
[0027]
When the magnetic body 20 is in proximity to the proximity switch 1, the output level indicates L because the amount of magnetic flux applied to the magnetic sensor 3 has decreased. After time T ₁ , when the magnetic body 20 is moved away from the proximity switch 1, the amount of magnetic flux applied to the magnetic sensor 3 increases, so that the output level gradually increases and is induced by the magnetic body 20. When there is no more magnetic flux, the output level H (> L) is constant. As described above, the output level in the proximity state and the separation state detected by the magnetic sensor 3 absorbs the assembly error and is set to a constant value in the proximity state and the separation state. On the other hand, it is possible to detect with high accuracy whether or not the magnetic body 20 is close.
[0028]
[Pedal switch]
Next, a pedal switch using the proximity switch 1 having the above configuration will be described.
[0029]
In FIG. 5, the pedal switch 10 for the pedal 11 includes a proximity switch 1 fixed to a vehicle body (not shown) and a magnetic body 20 fixed to the pedal 11 supported to be swingable with respect to the vehicle body. Yes.
[0030]
The pedal 11 is formed by connecting a rotating shaft 12 having an X axis direction as an axis and a flat tread plate 14 having a plane extending in the XY direction by an arm 13 having a longitudinal direction as a Y axis. . The arm 13 is bent at a portion from the base end, and has an inclined portion 13a in the vicinity of the rotating shaft 12 and a main shaft portion 13b in the Y-axis direction. As shown in FIG. 6, when the tread plate 14 is depressed, the pedal 11 is rotatable about the rotation shaft 12 to a position indicated by a dotted line in the drawing. In the following description, a state in which the tread plate 14 is not depressed is referred to as a “pause state” of the pedal 11.
[0031]
The magnetic body 20 is formed so as to have a flat plate extending in the YZ plane direction, and is fixed to the main shaft portion 13b of the arm 13 via a connecting portion 20a. The magnetic body 20 moves in the Y-axis direction and the Z-axis direction while being restrained in the X-axis direction as the pedal 11 rotates.
[0032]
The proximity switch 1 is fixed to the vehicle body so that the magnetic body 20 is inserted into the guide groove 7 of the proximity switch 1 when the pedal 11 is in a resting state.
In the above configuration, the magnetic body 20 fixed to the pedal 11 is inserted into the guide groove 7 of the proximity switch 1 when the pedal 11 is in a resting state. In this state, when the tread plate 14 of the pedal 11 is depressed and rotated, the magnetic body 20 moves together with the arm 13 of the pedal 11, and comes off the guide groove 7 of the proximity switch 1 and leaves the proximity switch 1. At this time, the magnetic sensor 3 detects the amount of magnetic flux and detects whether or not the pedal 11 is operated.
[0033]
For example, when the pedal 11 is a brake pedal and the proximity switch 1 is used as a stop lamp that is lit in conjunction with a brake operation in an automobile, the proximity switch 1 is driven via a connector 5 to drive the brake lamp of the automobile. Connected to a circuit (not shown).
[0034]
In the above configuration, when the pedal 11 is in the resting state, the proximity switch 1 outputs a detection signal of the output level L. In the processing circuit 4, it is determined whether or not the detection signal is equal to or less than a threshold value. If the output level is L, a determination signal (off signal) indicating that the detection signal is equal to or less than the threshold value is output. As a result, when the brake lamp drive circuit receives the off signal, the brake lamp (not shown) holds the brake lamp not shown.
[0035]
On the other hand, when the tread plate 14 is depressed, the pedal 11 rotates about the rotation shaft 12 to the position indicated by the dotted line in FIG. 6, and the magnetic body 20 moves away from the bias magnet 2 of the proximity switch 1. In this state, the proximity switch 1 outputs a detection signal at the output level H. The processing circuit 4 determines whether or not the detection signal is equal to or less than a threshold value. If the output level is H, a determination signal (ON signal) indicating that the detection signal is equal to or higher than the threshold value is output. As a result, the brake lamp drive circuit turns on a brake lamp (not shown) based on the ON signal.
[0036]
Therefore, according to the proximity switch 1 of the above embodiment, the following effects can be obtained.
(1) In the present embodiment, the partition plate 6a as a guide member for disposing the magnetic body 20 to face the bias magnet 2 at a predetermined interval, and the regulation for positioning the magnetic body 20 in contact with the partition plate 6a. It provided with the control part 6b as a member. Therefore, it is possible to prevent variations in the magnetic flux applied to the magnetic sensor 3 by setting the gap between the magnetic body 20 and the bias magnet 2 at a predetermined interval, that is, a constant interval, regardless of the assembly error.
[0037]
(2) Moreover, the partition plate 6a has the 1st guide surface 8a which makes the magnetic body 20 slidably contact, and the control part 6b has the 2nd guide surface 8b arrange | positioned facing the 1st guide surface 8a. Therefore, the effect described in the above (1) can be preferably obtained.
[0038]
(3) Furthermore, it has the inclined surfaces 8c and 8d as a guidance surface which guides the magnetic body 20 to the partition plate 6a. Therefore, the magnetic body 20 can be guided into the guide groove 7, and the effect described in the above (1) can be preferably obtained.
[0039]
(4) The bias magnet 2 and the magnetic sensor 3 are provided in a case 6 formed of a nonmagnetic material, and the partition plate 6 a and the restricting portion 6 b are formed in the case 6. Therefore, the effect described in (1) above can be obtained with a simple configuration.
[0040]
(5) Furthermore, a connector 5 for connecting to the outside of the case 6 and a processing circuit 4 for processing a signal output from the magnetic sensor 3 are disposed in the case 6. Therefore, a proximity switch having the effect described in the above (4) can be configured efficiently.
[0041]
The above embodiment may be embodied by changing to another example as follows.
In the above embodiment, the case 6 is provided with the connector 5 for connecting to the outside of the case 6 and the processing circuit 4 for processing a signal output from the magnetic sensor 3, but the proximity switch Is not limited to this configuration. For example, the connector 5 and the processing circuit 4 may be provided outside the case 6. Moreover, you may provide another member in a case.
[0042]
- Also, the opposing deployable guide member at a predetermined interval a magnetic material against the bias magnet, as long as the regulating member for positioning is brought into contact with the magnetic material in the guide member, the guide member and the regulating member which You may comprise as follows.
[0043]
Further, although the inclined surfaces 8c and 8d as the guide surfaces are provided, this may not be provided.
In addition, the partition plate 6a has the first guide surface 8a for sliding the magnetic body 20, and the restricting portion 6b has the second guide surface 8b disposed to face the first guide surface 8a. The first and second guide surfaces 8a and 8b do not have to be planar.
[0044]
For example, as shown in FIG. 7, a bar member 31 is arranged as a guide member at a predetermined interval with respect to the bias magnet 2, and a bar member 32 is further provided as a restricting member that contacts and positions the bar member 31. It may be arranged. Further, as shown in FIG. 8, the first guide surface 41 and the second guide surface 42 in which ridges are arranged on the surface may be used, and the magnetic body 20 may be brought into contact with the top of the ridges to be guided.
[0045]
【The invention's effect】
As described in detail above, according to the first to fourth aspects of the present invention, the magnetic flux applied to the magnetic sensor is set at a predetermined interval between the magnetic body and the bias magnet regardless of the assembly error. Variations can be prevented.
[Brief description of the drawings]
1A is a cross-sectional view in a cross-sectional direction, and FIG. 1B is a cross-sectional view in a longitudinal direction of a proximity switch according to the present embodiment.
FIG. 2 is a perspective view of the case.
FIG. 3 is a cross-sectional view for explaining the same operation.
FIG. 4 is a graph showing a change in magnetic field strength.
FIG. 5 is a front view schematically illustrating the pedal switch according to the embodiment.
FIG. 6 is a side view of the same.
FIG. 7 is a cross-sectional view schematically illustrating another example.
FIG. 8 is a cross-sectional view schematically illustrating another example.
[Explanation of symbols]
1 ... Proximity switch 2 ... Bias magnet 3 ... Magnetic sensor
4 ... Processing circuit
5 ... Connector
6 ... Case 6a ... Partition plate (guide member)
6b ... Restriction part (regulation member)
7 ... Guide groove 8a ... First guide surface 8b ... Second guide surface
8c, 8d ... inclined surfaces (guide surfaces)
9 ... Housing part 20 ... Magnetic material

Claims (4)

In a proximity switch provided with a bias magnet and a magnetic sensor for detecting a change in the amount of magnetic flux applied from the bias magnet in a case formed of a non-magnetic material,
A guide member for disposing the magnetic body opposite to the bias magnet at a predetermined interval; and a regulating member for positioning the magnetic body in contact with the guide member,
The case is formed with a guide groove and a receiving portion, and the guide groove is formed along the X axis, the Y axis, and the Z axis, which are three axes orthogonal to each other. The opposite Y-axis direction is opened, one end side in the Z-axis direction is connected, the other end side in the Z-axis direction is opened, and the guide member and the regulating member are formed on both sides in the X-axis direction of the guide groove. The proximity switch is characterized in that the bias magnet and the magnetic sensor are disposed in the housing portion.   The said guide member has a 1st guide surface which makes the said magnetic body slidably contact, and the said limitation member has a 2nd guide surface arrange | positioned facing the said 1st guide surface. Proximity switch.   The proximity switch according to claim 1, further comprising a guide surface that guides the magnetic body to the guide member. 4. The connector according to claim 1 , wherein a connector for connecting to the outside of the case and a processing circuit for processing a signal output from the magnetic sensor are disposed in the case. The proximity switch according to any one of the above.

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