JP4885086B2 - Non-contact switch - Google Patents

Description

  The present invention relates to a non-contact switch using a magnetic sensor.

  As a conventional technique, a concave portion is formed in a part of the N pole of the magnet, and three sides of the concave portion are surrounded by the N pole, and this concave portion is used as a detection region for detecting magnetic flux so that the magnetic member approaches the detection region. In addition, there is a non-contact switch in which a magnetic field sensitive element is disposed (for example, Patent Document 1).

According to this non-contact switch, when the magnetic member is displaced from a position away from the detection area to a position approaching the detection area, the N pole is detected in the detection area that is a magnetic flux-free space because the three sides are surrounded by the N pole. Magnetic flux is generated due to the magnetic flux flowing between the magnetic member and the magnetic member. The switch circuit can be turned on / off by detecting the generation of the magnetic flux by the magnetic field sensitive element.
Japanese Patent No. 2921603

  However, the conventional non-contact switch detects whether or not magnetic flux is generated in the detection region, so that malfunction occurs due to an external magnetic field, and there is a limit in improving detection accuracy. There was a limit to miniaturization.

  Accordingly, an object of the present invention is to propose a non-contact switch that can suppress malfunctions, improve detection accuracy, and can be miniaturized.

  In order to achieve the above object, the present invention has a substantially L-shape formed by a base portion and a convex portion, and having a step portion formed by the base portion and the convex portion. An end face and an end face of the convex part are magnetized to magnetic poles having the same polarity, and a magnet having a region where the magnetic vector is aligned in a predetermined direction, and a region where the magnetic vector of the magnet is aligned in a predetermined direction A magnetic sensor that outputs an output signal based on a change in the magnetic vector according to a distance from the magnetic member, and determines whether the switch circuit is on or off based on the output signal output from the magnetic sensor There is provided a non-contact switch comprising a determination unit.

  According to such a configuration, it is possible to provide a non-contact switch that can suppress malfunction, increase detection accuracy, and can be further downsized.

  Hereinafter, embodiments of the non-contact switch of the present invention will be described in detail with reference to the drawings.

[First embodiment]
(Configuration of vehicle 1)
FIG. 1A is a side view of a vehicle according to the first embodiment of the present invention, and FIG. 1B is a schematic view of the interior of the vehicle according to the first embodiment of the present invention. . The vehicle 1 decelerates the vehicle 1 by a brake device 2 as a non-contact switch that decelerates the vehicle 1 by a driver's operation, a brake lamp 10a that is lit (turned on) by a driver's brake operation, and a driver's brake operation. A hydraulic brake 10b, a panel 11 provided inside the vehicle 1 and provided with a brake device 2, an accelerator pedal 12 and the like, an accelerator pedal 12 capable of adjusting the acceleration of the vehicle 1 by a driver's operation, and the vehicle 1 And a shift lever 13 that can be operated such as traveling, stopping, and moving backward.

(Configuration of brake device 2)
FIG. 2A is a side view of the brake device according to the first embodiment of the present invention, and FIG. 2B is a front view of the brake device according to the first embodiment of the present invention. FIG. 3 is a block diagram of the brake device according to the first embodiment of the present invention.

  The brake device 2 includes a brake pedal 20 made of a ferromagnetic metal such as steel, a detected portion 20 a that changes a magnetic flux generated from a magnet, which will be described later, by approaching or leaving the sensor 26, and the brake pedal 20. As shown in FIG. 2 (b), the pedal pad 21 provided and the side surface of the panel 11 of the vehicle 1 are provided with through holes at positions corresponding to the through holes provided at the upper end of the brake pedal 20. 2, a pedal bracket 22 that supports the brake pedal 20 so as to be able to rotate and move in the direction of the arrow A shown in FIG. 2A and in the opposite direction of the arrow A, and a cylinder that operates the hydraulic brake 10 b by the operation of the driver. 24a and a piston 24 (not shown) in the cylinder 24a and a joint 24d provided at the tip together with the brake pedal 20 and the piston It is provided between the piston rod 24b that moves in conjunction with the pin 24c, the mounting portion 22a, and the brake pedal 20, and applies an elastic force to the brake pedal 20 in the direction opposite to the arrow A. A return spring 25 that returns to the initial position before the brake operation and a sensor 26 that is provided on the attachment portion 22a of the pedal bracket 22 and outputs an output voltage as an output signal based on the distance from the detected portion 20a.

  Further, the sensor 26 of the brake device 2 controls the vehicle 1 and is connected to an ECU (Electronic Control Unit) 100 as a determination unit provided in a storage unit (not shown) with a threshold value 101 described later via a connector unit 26B. The ECU 100 constitutes a non-contact switch together with the detected portion 20a and the sensor 26, compares the output voltage from the sensor 26 with the threshold value 101, determines the presence or absence of the brake operation, for example, determines that the brake operation has been performed. Then, control is performed to turn on (turn on) the brake lamp 10a. Since the brake device 2 performs non-contact control of lighting (ON) and extinguishing (OFF) of the brake lamp 10a accompanying the brake operation, the life of the brake device 2 can be extended as compared with the contact type switch.

(Configuration of sensor 26)
4 (a) is a perspective view of the sensor unit according to the first embodiment of the present invention, and FIG. 4 (b) is a front view of the sensor unit according to the first embodiment of the present invention. FIG. 4C is a side view of the sensor unit according to the first embodiment of the present invention. The sensor 26 is accommodated in a housing (not shown) and is molded with a resin material. The half bridge portions 261M and 261N constitute an MR sensor 261a to be described later, and have a connected shape in order to be fixed at the positions shown in FIGS. 4 (a), (b) and (c). Further, an integrated MR sensor 261a having half bridge portions 261M and 261N at positions corresponding to the regions A and B may be used, and at the positions of the half bridge portions 261M and 261N of the MR sensor 261a. In addition, the magnet 260 may be manufactured.

  The sensor 26 is roughly configured by a sensor portion 26A and a connector portion 26B, and the sensor portion 26A includes a magnet 260 having a substantially L shape and half bridge portions 261M and 261b described later.

(Configuration of magnet 260)
The magnet 260 is formed in an L shape by mixing Nd (neodymium) with resin, has a base portion 260a and a convex portion 260b, and a step portion 260f is formed by the base portion 260a and the convex portion 260b. Yes. In addition, the base portion 260a has an N extreme surface 260c and an S extreme surface 260e magnetized at the N pole at both ends, and the convex portion 260b has an N extreme surface 260d and an S extreme surface 260e. Have.

  Further, the magnet 260 is a surface facing the N extreme surface 260d and the S extreme surface 260e of the base portion 260a when a magnetizing piece approaches from the facing direction and a predetermined magnetic field is applied. The N extreme surface 260c is magnetized and formed. Note that the S pole and the N pole can function in the same manner even if they are magnetized in the reverse combination of those shown above. In addition, since the magnet 260 has small projection surfaces of the N extreme surfaces 260c and 260d shown in FIG. 4B, the sensor 26 can be downsized and the number of parts can be reduced.

(Configuration of MR sensor 261a)
FIG. 5 (a) is a schematic configuration diagram of the MR sensor according to the first embodiment of the present invention, and FIG. 5 (b) configures the MR sensor according to the first embodiment of the present invention. FIG. 6A is a schematic diagram of a bridge circuit, and FIG. 6A is a plane magnetic vector on which the half bridge portion of the MR sensor is arranged when the detection target portion according to the first embodiment of the present invention is approaching. 6B is a schematic diagram showing the orientation of the MR sensor, and FIG. 6B is a plan view of a magnetic field in which the half bridge portion of the MR sensor is arranged when the detected portion is separated according to the first embodiment of the present invention. It is the schematic showing the direction of the vector. 6A and 6B, the magnetic vector 262 in the plane S1 shown in FIG. 4A is measured. 6A shows a magnetic vector 262 when the distance d between the detected portion 20a shown in FIG. 4A and the N extreme surface 260c of the magnet 260 is 1 mm, and FIG. 6B shows the distance. The magnetic vector 262 is shown when d is 8 mm. Although the length of the magnetic vector 262 is proportional to the strength of the magnetic field, the size of the arrow is not related to the strength of the magnetic field.

  An MR sensor 261a shown in FIG. 5A is provided on a substrate 261A that is an insulator such as silicon and a substrate 261A, and using a ferromagnetic material such as Fe—Ni by a known method such as photolithography. The produced magnetoresistive elements 261B to 261E, an input terminal 261F connected to a power supply unit (not shown) of the vehicle 1, an earth terminal 261G connected to an earth circuit (not shown) of the vehicle 1, and the magnetoresistive elements 261B and 261C The output terminal 261H to which the midpoint potential V1 is output and the output terminal 261I to which the midpoint potential V2 of the magnetoresistive elements 261D and 261E are output are configured. Note that an output voltage V described later is a difference value (V1−V2) between V1 and V2. The output voltage V output from the MR sensor 261a is not limited to this, and the MR sensor 261a is provided with a threshold value 101 or the like to form an IC (Integrated Circuit), and an instruction to turn on or off the brake lamp 10a is given. The instruction signal to be output may be output to the ECU 100, and is not limited to this.

  Each of the magnetoresistive elements 261B to 261E is configured by a magnetic sensing part 261J whose electrical resistance value changes according to a change in the direction of the magnetic field, and a folded part 261K that connects the magnetic sensing parts 261J. When the direction of magnetic flux is θ = 0 ° shown in FIG. 5A, each of the magnetoresistive elements 261B to 261E has the minimum resistance value of the magnetoresistive elements 261C and 261D, and the resistance of the magnetoresistive elements 261B and 261E. When the value is maximum and θ = 45 °, the resistance values of the magnetoresistive elements 261B to 261E are equal, and when θ = 90 °, the resistance values of the magnetoresistive elements 261B and 261E are minimum and magnetic The resistance elements 261C and 261D are configured to have a maximum resistance value.

  Each of the magnetoresistive elements 261B to 261E forms a bridge circuit 261L shown in FIG. 5B, and the magnetoresistive elements 261B and 261E shown by vertical lines in FIG. The magnetoresistive element 261C or 261D indicated by the horizontal line in b) is rotated by 90 °.

  In order to stably and accurately detect the change in the distance d with respect to the sensor 26 of the detected portion 20a, the magnetic vector 262 is aligned in a predetermined direction and the magnetic vector 262 that is aligned by the change in the distance d is obtained. It is desirable to arrange the magnetic sensor in a region that changes in substantially the same direction. This is because the anisotropic magnetoresistive element used as a magnetic sensor in the present embodiment detects a change in the direction of the magnetic vector 262 of the magnetic field applied to the anisotropic magnetoresistive element. This is because it is not suitable for use in detecting a change in intensity. Therefore, in order to perform stable and accurate detection, it is necessary to apply a magnetic field at which the magnetic resistance value is saturated to the magnetic sensor by the magnet 260. This is because the magnetoresistive value is maximized by applying a magnetic field at which the magnetoresistive value is saturated to the magnetic sensor, and the change in the magnetoresistive value based on the change in the direction of the magnetic vector 262 is easily detected.

  In regions A and B shown in FIG. 6A, the magnetic vectors 262 are aligned in a certain direction, and FIG. 6B shows a state where the distance d between the detected portion 20a and the sensor 26 is large. The directions of the magnetic vectors 262 in the areas A and B shown in FIG. On the other hand, the magnetic vector 262 in the region near the magnetic flux near the center has a large change in the direction of the magnetic vector 262, but the magnetic flux is weak and a sufficient output cannot be obtained. Not suitable.

  From the above results, the half bridge portions 261M and 261N of the MR sensor 261a are within the plane S1 orthogonal to the plane including the N extreme surface 260c, as shown in FIG. 4A, and as shown in FIG. Thus, it is desirable that the magnetic vector 262 near the tip of the base portion 260c be disposed in the regions A and B in which the magnetic vector 262 is aligned in one direction. The arrangement positions of the half bridge portions 261M and 261N are not limited to this, and a region where the magnetic vectors 262 are aligned in one direction and the direction of the magnetic vector 262 changes due to the approach of the detected portion 20a, for example, the plane S1. As long as it is in a plane parallel to, it can be arranged freely. In addition, even if the arrangement positions of the half bridge portions 261M and 261N are shifted in the plane S1, the half bridge portions 261M and 261N are arranged symmetrically, so that the angle deviation of the magnetic vector 262 on the arranged plane S1 is shifted. The phase shift of the output voltage based on is canceled. In other words, d (the value of d at which the output voltage V in FIG. 7 described later becomes 0) does not change at the boundary of the presence or absence of the brake operation described later, so that the ECU 100 is stable and accurate based on the output voltage V. The presence or absence of brake operation can be determined.

  FIG. 7 is a schematic diagram regarding the output voltage of the MR sensor according to the first embodiment of the present invention, and shows a case where a voltage is applied to the bridge circuit 261L so that the maximum value of the output voltage V becomes 50 mV. Yes. The vertical axis represents the output voltage V, and the horizontal axis represents the distance d between the half bridge portions 261M and 261N and the detected portion 20a. A curve T1 represents a difference (V1−V2) between the midpoint potentials V1 and V2 of the half bridge portions 261M and 261N.

  The distance d between the detected portion 20a and the N extreme surface 260c of the magnet 260 is 1 mm when the driver does not perform the brake operation (initial position). The driver performs the brake operation, and the detected portion 20a Is 3 m in the direction of arrow A, the threshold value 101 is set to 0 mv so that the brake lamp 10a is lit (turned on). In addition, these values are not limited to this, For example, according to the attachment position of the sensor 26, the setting of the play of the brake device 2, etc., it can change freely.

(Operation)
Hereinafter, the operation of the present embodiment will be described in detail with reference to FIGS.

  When the driver performs a brake operation during the driving operation of the vehicle 1, the brake pedal 20 moves in the direction of the arrow A shown in FIG. 2 around the bolt 23 attached to the tip of the brake pedal 20. To do.

  As the brake pedal 20 moves in the direction of arrow A, the distance d shown in FIG. 4A is increased in the detected portion 20a, and the magnetic vector 262 is changed from the state shown in FIG. 5A to FIG. The state changes continuously.

  ECU 100 compares output voltage V output from sensor 26, that is, MR sensor 261a, with threshold value 101. When the brake operation exceeds 3 mm in the direction of arrow A, the distance d shown in FIG. 7 is 3 mm or more, and the sensor 26 outputs the output voltage V of 0 mV or more which is the threshold value 101, the ECU 100 performs the brake operation. Control is performed to turn on (turn on) the brake lamp 10a. At the same time, as the brake pedal 20 moves in the direction of arrow A, the piston rod 24b receives force through the piston pin 24c and the joint 24d and moves in the direction of arrow A, and presses the piston of the cylinder 24a (not shown). The hydraulic brake 10b is operated by the hydraulic pressure, and the vehicle 1 decelerates.

  When the driver's brake operation is finished and the distance d shown in FIG. 7 is 3 mm or less, the ECU 100 determines that the brake operation is finished, and performs control to turn off the brake lamp 10a. . At this time, since the brake pedal 20 returns to the initial position by the elastic force of the return spring 25, the piston pin 24c, the joint 24d, and the piston rod 24b move in the direction opposite to the arrow A, and the inside of the cylinder 24a is not shown. The piston moves in the direction opposite to the arrow A, the hydraulic pressure applied to the hydraulic brake 10b is released, and the brake operation ends.

(effect)
According to the first embodiment described above, malfunctions can be suppressed, detection accuracy can be increased, and further downsizing can be achieved.

[Second Embodiment]
(Constitution)
FIG. 8A is a perspective view of a sensor unit according to the second embodiment of the present invention, and FIG. 8B is a front view of the sensor unit according to the second embodiment of the present invention. FIG.8 (c) is a side view of the sensor part based on the 2nd Embodiment of this invention. In the present embodiment, only parts different from the first embodiment will be described.

  In the present embodiment, for example, MR sensors 261a and 261b having a bridge circuit 261L shown in FIG. 5B are used. The MR sensors 261a and 261b are arranged at the positions shown in FIGS. 8A, 8B, and 8C, but are not limited thereto, and the regions A and B shown in FIGS. 6A and 6B are used. Alternatively, the magnetic vector 262 can be freely arranged as long as it is in an area in which the magnetic vector 262 faces a predetermined direction.

  FIG. 9 is a schematic diagram relating to the output voltage of the MR sensor according to the second embodiment of the present invention, and the voltage is applied to the bridge circuit 261L shown in FIG. 5B so that the maximum value of the output voltage V is 50 mV. It represents about the case where is applied. The vertical axis represents the output voltage V, and the horizontal axis represents the distance d between the MR sensors 261a and 261b and the detected portion 20a. Curve T2 represents the output voltage of MR sensor 261a, curve T3 represents the output voltage of MR sensor 261b, and curve T4 represents the curve when the output voltage of curve T3 is inverted and added to curve T2. . In the curve T3, since the magnetic flux passing through the MR sensor 261b is 90 ° different from that of the MR sensor 261a, the sign of the output voltage V is reversed.

(Operation)
When the driver performs a brake operation during the driving operation of the vehicle 1, the brake pedal 20 moves in the direction of arrow A around the bolt 23 attached to the tip of the brake pedal 20.

  As the brake pedal 20 moves in the direction of arrow A, the distance d shown in FIG. 8A increases in the detected portion 20a, and the magnetic vector 262 changes from the state shown in FIG. 6A to FIG. 6B. The state changes continuously.

  MR sensor 261a outputs to ECU 100 an output obtained by inverting curve T2 shown in FIG. 9, and MR sensor 261b outputs curve T3 inverted.

  ECU 100 compares threshold value 101 with a value obtained by adding output voltages output from MR sensors 261a and 261b. The brake operation exceeds 3 mm in the direction of arrow A, the distance d shown in FIG. 8 is 3 mm or more, and an output voltage of 0 mV or more which is the threshold value 101 is output from the sensor 26, that is, the MR sensors 261a and 261b. The ECU 100 determines that the brake operation has been performed, and performs control for turning on (turning on) the brake lamp 10a. At the same time, as the brake pedal 20 moves in the direction of arrow A, the piston rod 24b receives force through the piston pin 24c and the joint 24d and moves in the direction of arrow A, and presses the piston of the cylinder 24a (not shown). The hydraulic brake 10b is operated by the hydraulic pressure, and the vehicle 1 decelerates.

  When the driver's brake operation is finished and the distance d shown in FIG. 8 is 3 mm or less, the ECU 100 determines that the brake operation is finished based on the output voltage of the sensor 26, and turns off the brake lamp 10a ( Off). At this time, since the brake pedal 20 returns to the initial position by the elastic force of the return spring 25, the piston pin 24c, the joint 24d, and the piston rod 24b move in the direction opposite to the arrow A, and the inside of the cylinder 24a is not shown. The piston moves in the direction opposite to the arrow A, the hydraulic pressure applied to the hydraulic brake 10b is released, and the brake operation ends.

  In the present embodiment, even if any one of the MR sensor 261a or MR sensor 261b fails, as shown in FIG. 9, it is based on a curve obtained by inverting the curve T2 or the curve T3. Based on the output voltage, ECU 100 can determine the presence or absence of a brake operation.

  In the present embodiment, the output voltage of the MR sensor 261b is inverted and added to the output voltage of the MR sensor 261a. However, the present invention is not limited to this, and the ECU 100 is based on the individual output voltages of the MR sensors 261a and 261b. May determine the presence or absence of a brake operation, or may take a difference between the output voltages of the MR sensors 261a and 261b and compare it with a threshold value 101 having a predetermined width. Furthermore, even in the configuration in which one MR sensor is arranged in the region A or B, the ECU 100 can similarly determine the presence or absence of a brake operation.

(effect)
According to the second embodiment described above, since the presence or absence of a brake operation using the two MR sensors 261a and 261b is detected, even if any one of the MR sensors breaks down, Presence / absence can be detected with high accuracy.

  The present invention is not limited by the first and second embodiments described above. For example, in the first and second embodiments, the lighting / extinguishing of the brake lamp 10a has been described. Needless to say, the present invention can also be applied to other controls such as lighting control in an instrument panel storage box. Needless to say, various modifications can be made without departing from or changing the technical idea of the present invention.

(A) is a side view of the vehicle which concerns on the 1st Embodiment of this invention, (b) is the schematic inside the vehicle which concerns on the 1st Embodiment of this invention. (A) is a side view of the brake device which concerns on the 1st Embodiment of this invention, (b) is a front view of the brake device which concerns on the 1st Embodiment of this invention. 1 is a block diagram of a brake device according to a first embodiment of the present invention. (A) is a perspective view of the sensor part which concerns on the 1st Embodiment of this invention, (b) is a front view of the sensor part which concerns on the 1st Embodiment of this invention, (c) is It is a side view of the sensor part which concerns on the 1st Embodiment of this invention. (A) is a schematic block diagram of MR sensor which concerns on the 1st Embodiment of this invention, (b) is the outline of the bridge circuit which comprises MR sensor which concerns on the 1st Embodiment of this invention. FIG. (A) is the schematic showing the direction of the magnetic vector of the plane where the half bridge part of MR sensor when the detected part concerning the 1st embodiment of the present invention approaches is arranged, (B) is the schematic showing the direction of the magnetic vector of the plane where the half bridge part of MR sensor when the detected part concerning the 1st embodiment of the present invention is separated is arranged. It is the schematic regarding the output voltage of MR sensor which concerns on the 1st Embodiment of this invention. (A) is a perspective view of the sensor part which concerns on the 2nd Embodiment of this invention, (b) is a front view of the sensor part which concerns on the 2nd Embodiment of this invention, (c) is FIG. 5 is a side view of a sensor unit according to a second embodiment of the present invention. It is the schematic regarding the output voltage of MR sensor which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Brake device, 10a ... Brake lamp, 10b ... Hydraulic brake, 11 ... Panel, 12 ... Accelerator pedal, 13 ... Shift lever, 20 ... Brake pedal, 20a ... Detected part, 21 ... Pedal pad, 22 ... Pedal bracket, 23 ... Bolt, 24a ... Cylinder, 24b ... Piston rod, 24c ... Piston pin, 24d ... Joint, 25 ... Return spring, 26A ... Sensor part, 26B ... Connector part, 26 ... Sensor, 101 ... Threshold , 260... Magnet, 260 a. ˜261E, magnetoresistive element, 261F, input terminal, 261G, ground terminal, 261H 261I: Output terminal, 261J: Magnetosensitive part, 261K ... Folding part, 261L ... Bridge circuit, 261M, 261N ... Half bridge part, 262 ... Magnetic vector, A, B, C ... Region, d ... Distance, S1 ... Plane, T1, T2, T3, T4 ... curve, V ... voltage, V1, V2 ... output voltage

Claims (3)

It has a substantially L-shape formed by a base portion and a convex portion, and has a step portion formed by the base portion and the convex portion, and the end surface of the base portion and the end surface of the convex portion in the step portion are the same. Magnets magnetized on magnetic poles having the following polarities and having magnetic vectors aligned in a predetermined direction;
A magnetic sensor arranged in a region where the magnetic vectors of the magnet are aligned in a predetermined direction and outputting an output signal based on a change in the magnetic vector according to a distance from the magnetic member;
A determination unit that determines whether the switch circuit is on or off based on the output signal output from the magnetic sensor;
A non-contact switch comprising:   2. The magnetic sensor includes a bridge circuit formed by a plurality of magnetoresistive elements, and the bridge circuit is disposed in the detection region as a half bridge circuit divided into two. Non-contact switch as described in.   The magnetic sensor comprises a plurality of magnetoresistive sensors in which bridge circuits are formed by a plurality of magnetoresistive elements, and the plurality of magnetoresistive sensors are arranged in the detection region. Non-contact switch.

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