JP2013096723A - Position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detector that is high in detection accuracy and compact in size.SOLUTION: A first magnet 21 and a second magnet 22 are provided on a stroke part 61 moving linearly in a stroke direction. The first magnet 21 and the second magnet 22 are magnetized in the same direction in a direction orthogonal to the stroke direction, and are provided so as to be separated from each other in the stroke direction. A hall element 51 is located away from an end part, facing fixed parts of the first magnet 21 and the second magnet 22, by a predetermined distance d, is provided in a fixed part 70, and is provided with a magnetic sensing surface 511 orthogonal to the stroke direction.

Description

  The present invention relates to a position detection device.

  Conventionally, a magnetic flux generation means and a magnetic flux detection element that detects a change in magnetic flux by moving relative to the magnetic flux generation means in accordance with the linear movement of the movable part, and the relative movement of the movable part based on the output signal of the magnetic flux detection element are provided. A position detection device that detects a position is known. For example, in the position detection device described in Patent Document 1, the Hall element is provided so as to be surrounded by a first magnet, a second magnet, a third magnet, and a fourth magnet.

JP 2008-45919 A

By the way, in the invention described in Patent Document 1, the first magnet and the fourth magnet are provided so that different magnetic poles face each other, and the second magnet and the third magnet are provided so that different magnetic poles face each other. . Further, the magnetization directions of the first magnet and the second magnet, and the third magnet and the fourth magnet are opposite to each other. Therefore, the magnetic flux between the first magnet and the second magnet and the third magnet and the fourth magnet is between the first magnet and the fourth magnet, and between the second magnet and the second magnet. Concentrate between 3 magnets. As a result, the output characteristics are non-linearly changing rapidly between the first magnet and the fourth magnet, and between the second magnet and the third magnet. In order to prevent the output characteristics from becoming non-linear, it is necessary to detect at a position deviated between the first magnet and the fourth magnet and between the second magnet and the third magnet. Will grow.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a small position detection device with high detection accuracy.

  According to the first aspect of the present invention, the position detection device detects the position of the movable part that linearly moves in the stroke direction, and the fixed part that moves relative to the movable part, the first magnetic flux generating means, the second magnetic flux generating means, and And a magnetic flux detecting means. The first magnetic flux generation means and the second magnetic flux generation means are provided in either the movable part or the fixed part, and the direction in which the magnetic flux is generated is the same in the direction orthogonal to the stroke direction, and are separated from each other in the stroke direction. Yes. The magnetic flux detection means is provided on either the movable part or the fixed part so as to be located a predetermined distance away from the end of the first magnetic flux generation means and the second magnetic flux generation means in the direction in which the magnetic flux is generated. It has a perpendicular magnetic sensing surface and outputs a signal according to the magnetic flux density perpendicular to the magnetic sensing surface. Here, “orthogonal” is not limited to a strictly orthogonal state but also includes a state where they intersect at a predetermined angle. Hereinafter, the term “orthogonal” has the same meaning when used.

  Here, the first magnetic flux generation means and the second magnetic flux generation means have the same direction of magnetic flux generation in the direction orthogonal to the stroke direction, and are separated from each other in the stroke direction. Since the different magnetic poles of the first magnetic flux generating means and the second magnetic flux generating means are not opposed to each other, the magnetic flux generated from the end face of the magnetic flux generating means spreads, and the decrease in the magnetic flux can be suppressed and the linearity of the output characteristics can be improved. . Therefore, the detection accuracy can be increased and the size can be reduced.

  Here, as an embodiment of the arrangement direction of the first magnetic flux generating means and the second magnetic flux generating means, according to the invention according to claim 2, the first magnetic flux generating means and the second magnetic flux generating means have N poles as magnetic flux detecting means. Magnetic flux is generated so as to face to the side. According to the invention of claim 3, the first magnetic flux generating means and the second magnetic flux generating means generate magnetic flux so that the south pole faces the magnetic flux detecting means side.

According to the invention which concerns on Claim 4, it is further provided with the 3rd magnetic flux generation means which was provided integrally with the magnetic flux detection means and generate | occur | produces a magnetic flux in the direction orthogonal to a stroke direction.
A magnetic flux collecting effect can be obtained by the third magnetic flux generating means provided integrally with the magnetic flux detecting means. For this reason, the magnetic flux density in the vicinity of the magnetic flux detection means can be increased. Therefore, the sensitivity and detection accuracy of the magnetic flux detection means can be increased. Further, for example, even when the position detection range of the movable part is expanded by increasing the distance between the first magnetic flux generation means and the second magnetic flux generation means, the first magnetic flux generation means and the second magnetic flux generation A decrease in detection accuracy can be suppressed without increasing the size of the generating means. Therefore, the position detection device can be reduced in size.

According to the fifth aspect of the present invention, the direction in which the magnetic flux is generated by the third magnetic flux generating means is opposite to the direction in which the magnetic flux is generated by the first magnetic flux generating means and the second magnetic flux generating means.
For this reason, the magnetic flux collection effect by the 3rd magnetic flux generation means can be improved, and the magnetic flux density near magnetic flux detection means can be raised more. Further, since the direction of the magnetic flux generated from the third magnetic flux generation means and the direction of the magnetic flux generated from the first magnetic flux generation means and the second magnetic flux generation means are the same in the vicinity of the magnetic flux detection means, the magnetic flux increases. Robustness can be improved.
According to the invention of claim 6, the direction in which the magnetic flux is generated by the third magnetic flux generating means is the same as the direction in which the magnetic flux is generated by the first magnetic flux generating means and the second magnetic flux generating means.

According to the seventh aspect of the present invention, the yoke that connects the end portion of the first magnetic flux generation means opposite to the magnetic flux detection means and the end portion of the second magnetic flux generation means opposite to the magnetic flux detection means is further provided. Prepare.
Thereby, demagnetization of the first magnetic flux generating means and the second magnetic flux generating means can be suppressed by increasing the permeance of the magnetic circuit, and the density of magnetic flux generated from the first magnetic flux generating means and the second magnetic flux generating means. To increase the signal-to-noise ratio. Further, the influence of the disturbance magnetic field can be reduced by the shielding effect of the yoke.

According to the invention of claim 8, the yoke has a plate-like bottom wall. The first magnetic flux generation means and the second magnetic flux generation means are provided on a surface of the bottom wall facing the magnetic flux detection means.
Thereby, by suppressing the magnetic flux generated from the end portions of the first magnetic flux generating means and the second magnetic flux generating means that do not face the magnetic flux detecting means, the magnetic flux density is increased, and the robustness with respect to the disturbance magnetic field can be improved. .

According to the invention of claim 9, the yoke further includes a first side wall and a second side wall that are erected on the magnetic flux detection means side from both end portions of the bottom wall in the stroke direction. The first magnetic flux generation means and the second magnetic flux generation means are provided between the first side wall and the second side wall.
Thereby, the shield effect of a yoke can be improved and the effect which reduces the influence of disturbance magnetic flux can be heightened.

According to the invention of claim 10, the yoke is erected in the same direction as the first side wall and the second side wall from both ends in the direction orthogonal to the stroke direction on a plane including one surface of the bottom wall. It further has a third side wall and a fourth side wall. The first magnetic flux generation means and the second magnetic flux generation means are provided between the third side wall and the fourth side wall.
Thereby, the shield effect of a yoke can be improved more and the effect which reduces the influence of disturbance magnetic flux can be heightened more.

According to the eleventh aspect of the present invention, the yoke further includes a top wall that connects ends of the first side wall and the second side wall opposite to the bottom walls.
Thereby, the shield effect of a yoke can be improved more and the effect which reduces the influence of disturbance magnetic flux can be heightened more.

According to the invention which concerns on Claim 12, the 1st magnetic flux generation means and the 2nd magnetic flux generation means are each provided in the both ends of the stroke direction of the bottom wall.
Thereby, the space | interval between a 1st magnetic flux generation means and a 2nd magnetic flux generation means can be enlarged, and the movement range of the magnetic flux detection means which moves between a 1st magnetic flux generation means and a 2nd magnetic flux generation means is made. Can be bigger. Therefore, the detection range can be increased.

According to the invention of claim 13, between the first magnetic flux generating means and the first side wall or the second side wall, and between the second magnetic flux generating means and the first side wall or the second side wall, There is a predetermined interval between.
Thereby, the magnetic flux entering the yoke is reduced, and the magnetic flux in the direction of the third magnetic flux generation means is increased, so that the magnetic flux collection effect of the third magnetic flux generation means can be further improved, and the magnetic flux density in the vicinity of the magnetic flux detection means Can be further enhanced.

According to the fourteenth aspect of the present invention, the first magnetic flux generating means and the second magnetic flux generating means are rectangular parallelepiped. Here, the term “cuboid” is not limited to a strict rectangular parallelepiped, and the angle between the adjacent surfaces is greater than 90 degrees or the angle between the surfaces is greater than 90 degrees. Including those formed with a small angle.
Thereby, by making the first magnetic flux generating means and the second magnetic flux generating means simple, variations in processing and assembly of the first magnetic flux generating means and the second magnetic flux generating means are suppressed, and the generated magnetic flux is equalized. In addition, robustness against misalignment can be further improved.

According to the invention of claim 15, the first magnetic flux generating means and the second magnetic flux generating means have the same magnetic characteristics.
Thereby, the effect which makes the generated magnetic flux equal can be heightened, and the effect which improves the robustness with respect to position shift can be heightened.

According to the invention of claim 16, the first magnetic flux generating means and the second magnetic flux generating means have different magnetic characteristics.
Thereby, the position where the output of a magnetic flux detection means is 0 can be set arbitrarily. Therefore, it is possible to increase the degree of freedom of position setting at which the outputs of the magnetic flux detection means, the first magnetic flux generation means, and the second magnetic flux generation means become zero.

(A) is a schematic diagram of the position detection apparatus of 1st Embodiment of this invention, (b) is a graph which shows the relationship between the relative position of 1st Embodiment of this invention, and magnetic flux density. The schematic diagram which shows magnetic flux distribution of the position detection apparatus of 1st Embodiment of this invention. 1 is a block diagram showing an overall configuration of a system to which a position detection device according to a first embodiment of the present invention is applied. The schematic diagram which shows the position detection apparatus by the modification of 1st Embodiment of this invention. (A) is a schematic diagram of the position detection apparatus of 2nd Embodiment of this invention, (b) is a graph which shows the relationship between the relative position of the position detection apparatus of 2nd Embodiment of this invention, and magnetic flux density. The schematic diagram which shows the position detection apparatus by the modification of 2nd Embodiment of this invention. (A) is a schematic diagram of the position detection apparatus of 3rd Embodiment of this invention, (b) is a graph which shows the relationship between the relative position of the position detection apparatus of 3rd Embodiment of this invention, and magnetic flux density. The schematic diagram of the position detection apparatus of 4th Embodiment of this invention. The schematic diagram of the position detection apparatus of 5th Embodiment of this invention. The schematic diagram of the position detection apparatus of 6th Embodiment of this invention. It is a schematic diagram of the position detection apparatus of 7th Embodiment of this invention, Comprising: (a) is sectional drawing of a position detection apparatus, (b) is the B direction view top view of (a). (A) The schematic diagram of the position detection apparatus of 8th Embodiment of this invention, (b) The graph which shows the relationship between the relative position of the stroke detection apparatus of 8th Embodiment of this invention, and magnetic flux density. (A) is a schematic diagram before expansion of the position detection range of the conventional position detection device, (b) is a schematic diagram showing a magnetic flux distribution of the conventional position detection device, and (c) is a diagram of the position detection device of the conventional position detection device. The graph which shows the relationship between a relative position and magnetic flux density.

Hereinafter, a position detection device according to a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The position detection device of the present invention is applied to a stroke portion of a transmission, an accelerator, a brake, or the like of an automobile and used for a stroke detection device that detects a relative stroke amount of the stroke portion.

  As shown in FIG. 3, the stroke amount detection device 10 includes a position detection device 1 and an ECU 100 (electronic control unit). The position detection device 1 outputs a signal detected by the relative movement between the stroke portion 61 and the fixed portion 70 of the linear actuator 60 to the ECU 100. The ECU 100 calculates the relative stroke amount between the stroke portion 61 and the fixed portion 70 based on the signal output from the position detection device 1, and performs feedback control of the linear actuator 60.

The configuration of the position detection device 1 will be described with reference to FIG. As shown in FIG. 1A, the position detection device 1 includes a fixed portion 70, a first magnet 21 as a first magnetic flux generation means, a second magnet 22 as a second magnetic flux generation means, and a magnetic flux detection means. The Hall element 51 is provided.
The first magnet 21 and the second magnet 22 are permanent magnets having the same shape and magnetic characteristics, and are formed in a rectangular parallelepiped. As shown in FIG. 3, the first magnet 21 and the second magnet 22 are provided in a stroke portion 61 that moves linearly and move together with the stroke portion 61. Here, the stroke part 61 corresponds to a “movable part” in the claims. Hereinafter, as shown in FIGS. 1A and 3, the moving direction of the stroke portion 61 is referred to as “X-axis direction”, and the direction orthogonal to the X-axis direction is referred to as “Y-axis direction”. In the present embodiment, the first magnet 21 and the second magnet 22 are provided so as to be magnetized substantially in the Y-axis direction and separated in the X-axis direction. Here, the “substantially Y-axis direction” is not limited to a state that exactly coincides with the Y-axis direction, but also includes a state that is inclined by a predetermined angle with respect to the Y-axis direction. The first magnet 21 and the second magnet 22 are provided such that the south pole faces the stroke portion 61 side and the north pole faces the opposite side of the stroke portion 61.

  The Hall element 51 has a magnetic sensitive surface 511, and the magnetic sensitive surface 511 is provided so as to be orthogonal to the X-axis direction. The hall element 51 is mounted on the hall IC chip 50. The Hall IC chip 50 is fixed to the fixing portion 70 so as to be located a predetermined distance d away from the N pole side ends of the first magnet 21 and the second magnet 22 in the Y-axis direction.

  When the first magnet 21 and the second magnet 22 move relative to the Hall element 51 along with the linear movement of the stroke portion 61, the density of the magnetic flux orthogonal to the magnetic sensitive surface 511 is as shown in FIG. To change. Moreover, the detailed magnetic flux distribution of the position detection apparatus 1 of this embodiment is shown in FIG.

  In the present embodiment, the position where the magnetic flux vector becomes 0 coincides with the midpoint O between the first magnet 21 and the second magnet 22. When the position of the Hall element 51 coincides with the midpoint O between the first magnet 21 and the second magnet 22, the detected relative position is set to zero. The relative position when the Hall element 51 is located on the first magnet 21 side with respect to the middle point O is represented by a negative value, and the relative position when the Hall element 51 is located on the second magnet 22 side with respect to the middle point O. The position is expressed as a positive value.

  Here, a position detection apparatus according to a comparative example of the first embodiment will be described with reference to FIG. In the comparative example, unlike the above embodiment, the Hall element is provided so as to be surrounded by four magnets. That is, the comparative example is similar to a conventional position detection device.

  As shown in FIG. 13A, the Hall element 501 is provided so as to be surrounded by the first magnet 201, the second magnet 202, the third magnet 203, and the fourth magnet 204. The first magnet 201 and the fourth magnet 204 are provided so that different magnetic poles face each other, and the second magnet 202 and the third magnet 203 are provided so that different magnetic poles face each other. FIG. 13B shows a detailed magnetic flux distribution of the position detection device of the comparative example. As shown in FIG. 13B, the magnetic flux between the first magnet 201 and the second magnet 202 and the third magnet 203 and the fourth magnet 204 is between the first magnet 201 and the fourth magnet 204, and , Concentrated between the second magnet 202 and the third magnet 203. As a result, the output characteristics are non-linearly changing abruptly between the first magnet 201 and the fourth magnet 204 and between the second magnet 202 and the third magnet 203. Here, when the first magnet 201, the second magnet 202, the third magnet 203, and the fourth magnet 204 move relative to the Hall element 501 along with the linear movement of the stroke portion 61, the magnetic flux in the vicinity of the Hall element 501. The density changes as shown in FIG. As shown in FIG. 13C, the graph line representing the change in the magnetic flux density is linear at the middle portion in the stroke direction, but not linear at both end portions in the stroke direction.

  On the other hand, in the present embodiment, the first magnet 21 and the second magnet 22 have the same direction in which magnetic flux is generated in the Y-axis direction, and are separated from each other in the X-axis direction. Thereby, since different magnetic poles do not face each other, the magnetic flux generated from the end surfaces of the first magnet 21 and the second magnet 22 spreads radially in the Y-axis direction. Therefore, the decrease in magnetic flux can be suppressed and the linearity of output characteristics can be improved. In addition, magnetic flux repulsion occurs between the first magnet 21 and the second magnet 22, so that the magnetic flux density between the first magnet 21 and the second magnet 22 can be made uniform. Therefore, even when the distance between the first magnet 21 and the second magnet 22 is increased, the detection accuracy is improved by suppressing the decrease in linearity of the change in the magnetic flux density in the vicinity of the Hall element 51. It is possible to increase the size and reduce the size.

  In the present embodiment, the first magnet 21 and the second magnet 22 are cuboids. Thereby, the 1st magnet 21 and the 2nd magnet 22 are made into a simple shape, and the dispersion | variation at the time of a process of the 1st magnet 21 and the 2nd magnet 22 and an assembly | attachment can be suppressed. In addition, the generated magnetic flux can be made equal, and the robustness against positional deviation can be improved.

  Further, in the present embodiment, the first magnet 21 and the second magnet 22 have the same shape and magnetic characteristics. Thereby, the effect which makes generated magnetic flux equivalent can be heightened, and the effect which improves the robustness with respect to position shift can be heightened.

Next, a position detection device according to a modification of the first embodiment will be described with reference to FIG.
As shown in FIG. 4, in the modification of the first embodiment, the first magnet 21 and the second magnet 22 are provided such that the N pole contacts the stroke portion 61 and the S pole faces the Hall element 51 side. Yes.
Such a configuration can obtain the same effects as those of the first embodiment.

(Second Embodiment)
A position detection apparatus according to a second embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st Embodiment, and description is abbreviate | omitted.
As shown in FIG. 5A, the position detection device 2 of the present embodiment further includes a third magnet 23 as third magnetic flux generation means.

  The third magnet 23 is magnetized in the Y-axis direction and is provided integrally with the Hall IC chip 50. Here, the third magnet 23 is provided such that the magnetization direction is opposite to the magnetization direction of the first magnet 21 and the second magnet 22. That is, the first magnet 21 and the second magnet 22 are provided so that the south pole faces the stroke portion 61 side, and the third magnet 23 is provided so that the south pole faces the side opposite to the stroke portion 61.

  In the present embodiment, when the first magnet 21 and the second magnet 22 move relative to the Hall element 51 as the stroke portion 61 moves linearly, the magnetic flux density in the vicinity of the magnetosensitive surface 511 is as shown in FIG. Changes as shown. As shown in FIGS. 5B and 1B, in the predetermined stroke range in the vicinity of the magnetic sensitive surface 511, the change range of the magnetic flux density of the present embodiment is larger than the change range of the magnetic flux density of the first embodiment. .

  As described above, in the present embodiment, a magnetism collecting effect can be obtained by the third magnet 23 that is magnetized in the Y-axis direction and provided integrally with the Hall IC chip 50. For this reason, the magnetic flux density in the vicinity of the Hall element 51 can be increased. Therefore, the sensitivity and detection accuracy of the Hall element 51 can be increased.

  In the present embodiment, the third magnet 23 is provided such that the magnetization direction is opposite to the magnetization direction of the first magnet 21 and the second magnet 22. For this reason, the magnetic flux collection effect by the 3rd magnet 23 can be improved, and the magnetic flux density of Hall element 51 vicinity can be raised more. Further, since the direction of the magnetic flux generated from the third magnet 23 and the direction of the magnetic flux generated from the first magnet 21 and the second magnet 22 are the same, the magnetic flux in the vicinity of the Hall element 51 is increased and the robustness is improved. Can be made.

Next, a position detection device according to a modification of the second embodiment will be described with reference to FIG.
As shown in FIG. 6, in the modification of the second embodiment, the third magnet 23 is provided so that the magnetization direction is the same as the magnetization direction of the first magnet 21 and the second magnet 22.

(Third embodiment)
A position detection apparatus according to a third embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as the said 2nd Embodiment, and description is abbreviate | omitted.
As shown in FIG. 7A, the position detection device 3 of the present embodiment further includes a yoke 30. The yoke 30 has a bottom wall 33. The bottom wall 33 is formed in a plate shape from a magnetic material, and is provided so that one surface of the bottom wall 33 abuts the S pole of the first magnet 21 and the S pole of the second magnet 22. Further, the first magnet 21 and the second magnet 22 are respectively provided at both ends of the bottom wall 33 in the X-axis direction.

  In the present embodiment, when the first magnet 21 and the second magnet 22 move relative to the Hall element 51 along with the linear movement of the stroke portion 61, the magnetic flux density in the vicinity of the magnetic sensitive surface 511 is as shown in FIG. Changes as shown. As shown in FIGS. 7B and 7B, in the predetermined stroke range in the vicinity of the magnetic sensitive surface 511, the magnetic flux density change range of the third embodiment is larger than the magnetic flux density change range of the second embodiment. large.

  As described above, in this embodiment, the yoke 30 is further provided. For this reason, demagnetization of the first magnet 21 and the second magnet 22 can be suppressed by increasing the permeance of the magnetic circuit, and the density of the magnetic flux generated from the first magnet 21 and the second magnet 22 is increased. The signal to noise ratio can be increased. Further, the influence of the disturbance magnetic field can be reduced by the shielding effect of the yoke 30. Therefore, compared with the said 1st Embodiment and 2nd Embodiment, the reduction | decrease of the magnetic flux density detected by the Hall element 51 can be suppressed (FIG.1 (b), FIG.5 (b), and FIG.7 (b)). reference).

  In the present embodiment, the bottom wall 33 is formed in a plate shape. Thereby, by suppressing the magnetic flux emitted from the end portions of the first magnet 21 and the second magnet 22 that do not face the Hall element 51, the magnetic flux density is increased, and the robustness with respect to the disturbance magnetic field can be improved.

  Further, in the present embodiment, the first magnet 21 and the second magnet 22 are respectively provided at both ends of the bottom wall 33 in the X-axis direction. Thereby, the space | interval between the 1st magnet 21 and the 2nd magnet 22 can be enlarged, and the movement range of the Hall element 51 which moves between the 1st magnet 21 and the 2nd magnet 22 can be enlarged. it can. Therefore, the detection range can be increased by increasing the arrangement interval between the first magnet 21 and the second magnet 22.

(Fourth embodiment)
A position detection apparatus according to a fourth embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as the said 3rd Embodiment, and description is abbreviate | omitted.
As shown in FIG. 8, the yoke 34 of the position detection device 4 of the present embodiment further includes a first side wall 341 and a second side wall 342, and is formed in a U shape so that the yoke of the third embodiment described above. Different from 30. Here, the first side wall 341 and the second side wall 342 are erected in the Y axis direction from both ends of the bottom wall 33 in the X axis direction. Further, the first side wall 341 and the second side wall 342 are erected on the Hall element 51 side of the bottom wall 33. The first magnet 21 and the second magnet 22 are provided at both ends of the bottom wall 33 in the X-axis direction between the first side wall 341 and the second side wall 342. The first magnet 21 contacts the first side wall 342, and the second magnet 22 contacts the second side wall 343.

  As described above, in the present embodiment, the yoke 34 further includes the first side wall 341 and the second side wall 342, and the first magnet 21 and the second magnet 22 include the first side wall 341 and the second side wall 342. It is provided between. Thereby, compared with the said 3rd Embodiment, the shielding effect of the yoke 34 can be improved and the effect of reducing the influence of a disturbance magnetic field can be heightened.

(Fifth embodiment)
A position detection apparatus according to a fifth embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as the said 4th Embodiment, and description is abbreviate | omitted.
As shown in FIG. 9, in the present embodiment, the first magnet 21 and the second magnet 22 are provided between the first side wall 341 and the second side wall 342 and are provided at both ends of the bottom wall 33 in the X-axis direction. It has been. In addition, a gap having a predetermined interval is formed in the X-axis direction between the first magnet 21 and the first side wall 342 and between the second magnet 22 and the second side wall 343.

  As described above, in the present embodiment, a gap having a predetermined interval is formed in the X-axis direction between the first magnet 21 and the first side wall 342 and between the second magnet 22 and the second side wall 343. Has been. As a result, the magnetic flux entering the yoke 34 is reduced and the magnetic flux in the direction of the third magnet 23 is increased, so that the magnetic collection effect of the third magnet 23 can be further improved compared to the fourth embodiment, and the hole The magnetic flux density in the vicinity of the element 51 can be further increased.

(Sixth embodiment)
A position detection apparatus according to a sixth embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as the said 5th Embodiment, and description is abbreviate | omitted.
As shown in FIG. 10, the yoke 36 of the position detection device 6 of the present embodiment further has a top wall 363 provided on the opposite side of the bottom wall 33 of the first side wall 341 and the second side wall 342, It differs from the yoke 34 of the said 5th Embodiment by being formed in the square frame shape.

  Here, the first magnet 21 and the second magnet 22 are accommodated inside the yoke 36. The Hall IC 50 and the third magnet 23 are fixed to the fixing portion 70 so as to be surrounded by the bottom wall 33, the first side wall 361, the second side wall 362, and the top wall 363.

  As described above, in the present embodiment, the first magnet 21, the second magnet 22, the third magnet 23, and the Hall IC 50 are surrounded by the yoke 36. Thereby, compared with the said 4th Embodiment and 5th Embodiment, the shield effect of the yoke 36 can be improved more and the effect of reducing the influence of a disturbance magnetic field can be heightened more.

(Seventh embodiment)
FIG. 11 shows a position detection apparatus according to a seventh embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as the said 5th Embodiment, and description is abbreviate | omitted.
As shown in FIG. 11, the yoke 37 of the position detection device 7 of the present embodiment further includes a third side wall 373 and a fourth side wall 374, and is formed in a square bottomed cylindrical shape. The yoke 34 is different (see FIG. 11B). The third side wall 373 and the fourth side wall 374 are erected in the Y-axis direction from both ends in the direction orthogonal to the X-axis direction on a plane including one surface of the bottom wall 33.

  Here, the first magnet 21 and the second magnet 22 are accommodated inside the yoke 37. Further, the Hall IC 50 and the third magnet 23 are fixed to the fixing portion 77 so as to be surrounded by the first side wall 341, the second side wall 342, the third side wall 373, and the fourth side wall 374 (FIG. 11 ( a) and FIG. 11 (b)).

  As described above, in the present embodiment, the first magnet 21, the second magnet 22, the third magnet 23, and the Hall IC 50 are the first side wall 341, the second side wall 342, the third side wall 373, and the fourth side. Surrounded by side walls 374. Thereby, compared with the said 4th Embodiment and 5th Embodiment, the shield effect of the yoke 36 can be improved more and the effect of reducing the influence of a disturbance magnetic field can be heightened more.

(Eighth embodiment)
FIG. 12 shows a position detection apparatus according to the eighth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as the said 3rd Embodiment, and description is abbreviate | omitted.
As shown in FIG. 12, the position detection device 8 of the present embodiment includes a first magnet 21, a second magnet 24, a hall element 51, and a third magnet 23.
The first magnet 21 and the second magnet 24 are formed in a rectangular parallelepiped. In the present embodiment, the second magnet 24 is formed larger than the first magnet 21. When the Hall element 51 moves relative to the first magnet 21 and the second magnet 24 along with the linear movement of the stroke portion 61, the magnetic flux density detected by the magnetic sensitive surface 511 is as shown in FIG. Change.

  As described above, in the present embodiment, since the first magnet 21 and the second magnet 24 are different in size, the position O1 at which the magnetic flux becomes 0 is between the first magnet 21 and the second magnet 24. It is different from the position O2, which is a point. Thereby, the freedom degree of the setting position where the magnetic flux of Hall element 51, the 1st magnet 21, and the 2nd magnet 24 becomes 0 can be raised.

(Other embodiments)
In the above embodiment, a permanent magnet is used as the magnetic flux generating means. On the other hand, in another embodiment, an electromagnet may be used as the magnetic flux generation means.
In the above embodiment, the Hall element is provided on the N pole side of the first magnet and the second magnet at a predetermined distance from the first magnet and the second magnet. On the other hand, in another embodiment, the Hall element may be provided on the S pole side of the first magnet and the second magnet at a predetermined distance from the first magnet and the second magnet.
In the said embodiment, the magnet is formed in the rectangular parallelepiped. On the other hand, in another embodiment, the magnet may be formed in a columnar shape or a polygonal column shape.
In the above embodiment, the first magnet and the second magnet are provided in the stroke portion, and the Hall element and the third magnet are provided in the fixed portion. On the other hand, in other embodiments, the Hall element and the third magnet may be provided in the stroke portion, and the first magnet and the second magnet may be provided in the fixed portion.

In the second embodiment, the direction in which the magnetic flux of the first magnet and the second magnet is generated is opposite to the direction in which the magnetic flux of the third magnet is generated. On the other hand, in other embodiments, the direction in which the magnetic flux of the first magnet and the second magnet is generated may be the same as the direction in which the magnetic flux of the third magnet is generated.
In the said 7th Embodiment, the yoke is formed in the square bottomed cylindrical shape which consists of a bottom wall, a 1st side wall, a 2nd side wall, a 3rd side wall, and a 4th side wall. On the other hand, it is good also as forming in the square cylinder shape in which any one of the 1st side wall, the 2nd side wall, the 3rd side wall, and the 4th side wall opened.
In the eighth embodiment, the first magnet and the second magnet having different sizes are used. On the other hand, in other embodiments, the first magnet and the second magnet having the same size and different magnetic characteristics may be used.
The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

1, 2, 3, 4, 5, 6, 7, 8 ... position detection device,
21 ... 1st magnet (1st magnetic flux generation means),
22, 24 ... second magnet (second magnetic flux generating means),
51 ... Hall element (magnetic flux detection means),
61 ・ ・ ・ Stroke part (movable part),
70, 77... Fixed part,
511: Magnetic sensitive surface.

Claims (16)

A position detection device that detects the position of a movable part that linearly moves in a stroke direction,
A fixed part that moves relative to the movable part;
The first magnetic flux generating means and the second magnetic flux generating means, which are provided in either the movable portion or the fixed portion, have the same direction in which magnetic flux is generated in a direction orthogonal to the stroke direction, and are separated from each other in the stroke direction. Magnetic flux generating means;
The first magnetic flux generating means and the second magnetic flux generating means are provided on either the movable portion or the fixed portion so as to be located at a predetermined distance from the end portions in the direction in which the magnetic flux is generated, and in the stroke direction Magnetic flux detecting means having a perpendicular magnetic sensing surface and outputting a signal corresponding to the density of the magnetic flux perpendicular to the magnetic sensitive surface;
A position detection device comprising:   2. The position detecting device according to claim 1, wherein the first magnetic flux generating means and the second magnetic flux generating means generate magnetic flux so that an N pole faces the magnetic flux detecting means.   2. The position detection device according to claim 1, wherein the first magnetic flux generation means and the second magnetic flux generation means generate magnetic flux so that an S pole faces the magnetic flux detection means.   The position detection according to any one of claims 1 to 3, further comprising third magnetic flux generation means that is provided integrally with the magnetic flux detection means and generates a magnetic flux in a direction orthogonal to the stroke direction. apparatus.   5. The position detection according to claim 4, wherein a direction in which the magnetic flux is generated by the third magnetic flux generation unit is opposite to a direction in which the magnetic flux is generated by the first magnetic flux generation unit and the second magnetic flux generation unit. apparatus.   The position detection according to claim 4, wherein the direction in which the magnetic flux is generated by the third magnetic flux generation means is the same as the direction in which the magnetic flux is generated by the first magnetic flux generation means and the second magnetic flux generation means. apparatus.   A yoke that connects an end of the first magnetic flux generation means opposite to the magnetic flux detection means and an end of the second magnetic flux generation means opposite to the magnetic flux detection means; The position detection device according to any one of claims 1 to 6. The yoke has a plate-like bottom wall;
The said 1st magnetic flux generation means and the said 2nd magnetic flux generation means are provided in the surface facing the said magnetic flux detection means of the said bottom wall, The Claim 1 characterized by the above-mentioned. Position detection device. The yoke further includes a first side wall and a second side wall that are erected on both sides of the stroke direction of the bottom wall on the magnetic flux detection means side,
9. The position detection device according to claim 8, wherein the first magnetic flux generation means and the second magnetic flux generation means are provided between the first side wall and the second side wall. The yoke includes a third side wall and a second side wall erected in the same direction as the first side wall and the second side wall from both ends in a direction perpendicular to the stroke direction on a plane including one surface of the bottom wall. Further comprising four side walls,
The position detection device according to claim 9, wherein the first magnetic flux generation unit and the second magnetic flux generation unit are provided between the third side wall and the fourth side wall.   The position detection device according to claim 9, wherein the yoke further includes a top wall that connects ends of the first side wall and the second side wall opposite to the bottom wall.   The position detection according to any one of claims 8 to 11, wherein the first magnetic flux generation means and the second magnetic flux generation means are respectively provided at both ends of the bottom wall in the stroke direction. apparatus.   Between the first magnetic flux generation means and the first side wall or the second side wall, and between the second magnetic flux generation means and the first side wall or the second side wall. The position detecting device according to any one of claims 9 to 12, wherein a predetermined gap is formed.   The position detection device according to claim 1, wherein the first magnetic flux generation unit and the second magnetic flux generation unit have a rectangular parallelepiped shape.   The position detection device according to claim 1, wherein the first magnetic flux generation unit and the second magnetic flux generation unit have the same magnetic characteristics.   The position detection device according to claim 1, wherein the first magnetic flux generation unit and the second magnetic flux generation unit have different magnetic characteristics.

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