JP2004354138A - Position detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detection apparatus capable of achieving a compact mounting space, using an inexpensive magnet having a small magnetic force, and avoiding reductions in accuracy in magnetic field detection. <P>SOLUTION: A magnetic field generating part 3 and a magnetic field detection part 4 are opposed to each other at an interval and provided for either a fixed member 1 or a moving member 2 movable with respect to the fixed member 1. A movable member 100 is provided with a magnetic field shielding body 5 which freely enters and retreats from the interval between the magnetic field generating part 3 and the magnetic field detection part 4. The other of the fixed member 1 and the moving member 2 is provided with a contact part 1a as a movable member pressing means 200 for pressing the movable member 100 so that the state of entry and retreat of the magnetic field shielding body 5 between the magnetic field generating part 3 and a magnetic field detection part 4 may be altered with the movement of the moving member 2 with respect to the fixed member 1. A position determination part 11 for determining the position of the moving member 2 with respect to the fixed member 1 on the basis of the information detected by the magnetic field detection part 4 is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a position detection device that detects a position of a movable member movable with respect to a fixed member with respect to the fixed member.
[0002]
[Prior art]
The position detecting device is used, for example, in a vehicle seat position adjusting device for an automobile or the like to detect a moving position of a seat. Conventionally, an iron plate member having an L-shaped cross section is installed on the upper rail side constituting the seat position adjusting device, while a magnet and a magnetic field detecting element such as a Hall IC are arranged on the lower rail side so as to face each other with a gap therebetween. A type sensor is installed, and the L-shaped iron plate member enters and exits the gap of the U-shaped sensor in accordance with the sliding movement of the seat back and forth, and the position of the upper rail with respect to the lower rail based on the detection signal of the magnetic field detecting element. (For example, see Patent Document 1).
[0003]
Further, as an improvement of the seat position detecting device of Patent Document 1, a magnetic field detecting element fixedly installed on the upper rail side and a magnet provided at an upper end portion are attached by a spring so as to return to a position facing the magnetic field detecting element. A lever is provided to be rotatable around the axis of the horizontal axis, and the lower rail side member contacts the lower end of the lever to rotate the lever in accordance with the sliding movement of the seat back and forth. With the rotation of the lever, the magnet at the upper end of the lever deviates from the position facing the magnetic field detecting element and the detection signal of the magnetic field detecting element changes, thereby detecting the position of the upper rail with respect to the lower rail (for example, Patent Document 1). 2, see Patent Document 3).
[0004]
[Patent Document 1]
US Pat. No. 6,053,529 [Patent Document 2]
JP 2002-337575 A [Patent Document 3]
JP-A-2002-264700
[Problems to be solved by the invention]
The technique described in Patent Document 1 has the following disadvantages. First, the mounting space increases. That is, since the U-shaped sensor and the L-shaped member are installed on the lower rail and the upper rail, which are separate members, respectively, and the L-shaped member enters and exits the gap between the U-shaped sensors, it is necessary to assemble each member at the time of assembly. Due to dimensional variations, the gap between the U-shaped sensors must be widened, and the range obtained by multiplying the sliding distance of the L-shaped member in the front-back direction by the cross-sectional area of the L-shaped member becomes a large dead space.
Second, it requires expensive magnets. That is, since the gap of the U-shaped sensor is inevitably wide as described above, in order to allow the magnetic field of the magnet to reach the magnetic field detecting element at a long distance, the magnet must be made of an expensive material such as a rare earth material having a strong magnetic force. Need to be In addition, since the U-shaped sensor incorporates a strong magnetic magnet, the U-shaped sensor is attracted to a surrounding iron member when the U-shaped sensor is mounted on the seat position adjusting device, and disadvantages such as difficulty in mounting work arise. .
[0006]
Patent Documents 2 and 3 disclose a configuration for avoiding the disadvantage in the technique of Patent Document 1. However, in the techniques described in Patent Documents 2 and 3, the relative position between the magnet provided on the lever side and the fixedly installed magnetic field detecting element slightly changes depending on the movement of the lever during the rotation operation and the return state to the return position. As a result, the magnetic field detection value becomes unstable, and the magnetic field detection accuracy may be reduced.
[0007]
In view of the above circumstances, an object of the present invention is to use a technical configuration different from the techniques described in Patent Documents 2 and 3 to avoid the disadvantage of the technique of Patent Document 1 and to avoid a decrease in magnetic field detection accuracy. To provide a position detecting device.
[0008]
[Means for Solving the Problems]
A first characteristic configuration of the position detection device according to the present invention for realizing the above object is, as described in claim 1, provided on one of a fixed member and a movable member movable with respect to the fixed member. A magnetic field generation unit and a magnetic field detection unit for detecting a magnetic field generated by the magnetic field generation unit are provided so as to be opposed to each other with a gap therebetween, and are capable of entering and leaving the gap between the magnetic field generation unit and the magnetic field detection unit. A movable member provided with a magnetic shield is provided, and a gap between the magnetic field generation unit and the magnetic field detection unit is provided on one of the fixed member and the movable member in accordance with the movement of the movable member with respect to the fixed member. Movable member pressing means for pressing the movable member so that the state of entry and exit of the magnetic shield with respect to the movable member is changed, and the movable member with respect to the fixed member based on information detected by the magnetic field detection unit. Lies in that the position determination unit for determining the position is provided.
[0009]
That is, when the movable member moves with respect to the fixed member, the movable member provided on one of the fixed member and the movable member is pressed by the movable member pressing means provided on the other of the fixed member and the movable member. The magnetic field generator of the magnetic shield provided on the movable member in a state in which the movable member can freely enter and exit the gap between the magnetic field generator and the magnetic field detector, which are disposed opposite to one of the fixed member and the movable member with a gap therebetween. The state of the moving member relative to the fixed member is determined based on the magnetic field detection information of the magnetic field detection unit because the entry and exit states of the magnetic field detection unit and the gap between the magnetic field detection unit and the magnetic field detection unit change. Is determined.
[0010]
Therefore, among the fixed member and the moving member, the same member provided with the magnetic field generating unit and the magnetic field detecting unit is provided with the movable member including the magnetic shield that enters the gap between the magnetic field generating unit and the magnetic field detecting unit. The space between the magnetic field generating unit and the magnetic field detecting unit is made as small as possible without depending on the dimensional variation between the fixed member and the moving member, and the mounting space is reduced, and at the same time, an inexpensive magnet with a small magnetic force is used as the magnetic field generating unit. It can be used.
Further, as described above, since the magnetic field generation unit and the magnetic field detection unit are arranged opposite to each other in a fixed state with a small gap therebetween, compared to a detection configuration in which the positional relationship between the magnetic field generation unit and the magnetic field detection unit changes during the detection operation. The magnetic field detection value is stabilized, and a decrease in the magnetic field detection accuracy can be avoided.
As a result, according to the first characteristic configuration, it is possible to reduce the mounting space and to use an inexpensive magnet having a small magnetic force, thereby eliminating the disadvantage of the technology of Patent Document 1 and avoiding a decrease in the magnetic field detection accuracy. It is possible to provide a position detecting device that has been made.
[0011]
The second characteristic configuration is the same as the first characteristic configuration, wherein the movable member includes the magnetic shield at one end side, and the fixed member and the moving member at an intermediate position. In that the movable member pressing means is constituted by a contact portion that contacts the other end of the rotating member.
[0012]
That is, when the contact portion that constitutes the movable member pressing means contacts the other end side portion of the rotating member that constitutes the movable member, it is rotatable to one of the fixed member and the moving member at an intermediate position. The rotating member supported by the rotating member is rotated, and the magnetic shield provided at one end of the rotating member enters or exits a gap between the magnetic field generating section and the magnetic field detecting section, and If the portion does not contact the other end of the rotating member, the magnetic shield of the rotating member retreats or enters from the gap between the magnetic field generating unit and the magnetic field detecting unit.
Therefore, since the movable member is constituted by the rotating member, the movable range can be reduced and miniaturized as compared with a movable member which moves linearly, and the movable member pressing means is constituted by the contact portion. Therefore, the contact portion can be simply formed by a part of the fixed member or the movable member provided with the movable member pressing means or the contact plate attached thereto, and a preferred embodiment of the position detecting device is provided. You.
[0013]
According to a third feature configuration, as set forth in claim 3, in the first or second feature configuration, the magnetic shield is made of a magnetic material that can be attracted by a magnetic field generated by the magnetic field generation unit. It is in the point.
[0014]
Therefore, the magnetic material constituting the magnetic shield is attracted by the magnetic field generated by the magnetic field generator, and the movable member is maintained in a state where the magnetic shield is located in the gap between the magnetic field generator and the magnetic field detector. Therefore, there is no need for an urging unit such as a spring for maintaining the movable member in a state where the magnetic shield is located in a gap between the magnetic field generating unit and the magnetic field detecting unit, and the position detection is configured simply. A preferred embodiment of the device is provided.
[0015]
According to a fourth aspect of the present invention, as set forth in claim 4, in any one of the first to third aspects, the movable member is provided in a gap between the magnetic field generating section and the magnetic field detecting section by gravity. The point is that it is formed so as to return to the state where the magnetic shield is located.
[0016]
Therefore, the movable member returns to a state in which the magnetic shield is located in the gap between the magnetic field generation unit and the magnetic field detection unit due to the action of gravity. A preferred embodiment of a position detecting device which is simple and does not require an urging means such as a spring for returning the movable member to a state where the magnetic shield is located is provided.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment in which the position detecting device according to the present invention is applied to a vehicle seat position adjusting device will be described with reference to the drawings.
[0018]
As shown in FIGS. 1 and 2, a lower rail 1 as a fixed member and an upper rail 2 as a movable member movable with respect to the lower rail 1 are provided, and one of the lower rail 1 and the upper rail 2 ( In the figure, a magnet 3 as a magnetic field generating unit and a Hall IC 4 as a magnetic field detecting unit for detecting a magnetic field generated by the magnet 3 are provided on the upper rail 2) so as to be horizontally opposed to each other with a gap therebetween. A movable member 100 provided with a magnetic shield 5 that can enter and exit the gap between the Hall IC 3 and the Hall IC 4 is provided.
[0019]
The movable member 100 is provided with the magnetic shield 5 at one end (upper side) 6b and as a rotating member 6 rotatably supported on the upper rail 2 around the horizontal axis X at the intermediate portion 6a. Is formed. The magnetic shield 5 is made of a magnetic material that can be attracted by the magnetic field generated by the magnet 3 (specifically, a thin iron plate member 5 formed in a U shape in plan view). Actually, the magnet 3, the Hall IC 4, the rotating member 6, and the like are housed and held in a sensor case 10 attached to a side surface of the upper rail 2.
[0020]
Further, the rotating member 6 is formed so as to return to a state where the magnetic shield 5 is positioned in a gap between the magnet 3 and the Hall IC 4 by gravity. Specifically, as shown in FIG. 2, the lower side portion 6c of the rotating member 6 is formed of a heavy iron member, and the lower side iron member and the upper side iron plate member 5 are formed by resin molding. The rotating member 6 is formed in an elongated lever shape by being integrally connected. The lower portion 6c of the rotating member 6 protrudes below the bottom opening of the sensor case 10.
[0021]
As the upper rail 2 moves relative to the lower rail 1, the magnetic shield 5 enters the gap between the magnet 3 and the Hall IC 4 into one of the lower rail 1 and the upper rail 2 (the lower rail 1 in the figure). A movable member pressing means 200 for pressing the movable member (rotating member) 6 so as to change the retreat state is provided. The movable member pressing means 200 is configured as a contact portion 1 a that contacts the other end side portion (lower side portion) 6 c of the rotating member 6. Here, the contact portion 1a is configured using the upper surface portion 1a of the lower rail 1, and at the time of contact, the rotating member 6 is rotated so that the magnetic shield 5 at the one end side portion 6b is connected to the magnet 3 and the magnet 3. It is caused to enter the gap of the Hall IC 4.
[0022]
Further, there is provided a position determining unit 11 for determining the position of the upper rail 2 with respect to the lower rail 1 based on the magnetic field detection information of the Hall IC 4. Specifically, a connector 7 for outputting a detection signal of the Hall IC 4 is provided in the sensor case 10, and the connector 7 and the position determination unit 11 are connected by a harness, and the detection signal of the Hall IC 4 is transmitted to the position determination unit 11. Is configured to be input.
[0023]
Next, the operation of the position detecting device having the above configuration will be described.
As shown in FIG. 1A, when the upper rail 2 moves forward (to the left in the drawing) with respect to the lower rail 1, the upper surface 1 a of the lower rail 1 contacts the lower portion 6 c of the rotating member 6. Since the rotating member 6 is not hit, the rotating member 6 returns to the vertical position due to its own weight, and the iron plate member 5 is attracted to the magnet 3, and the state where the iron plate member 5 is located in the gap between the magnet 3 and the Hall IC 4 is maintained. In this state, as shown in FIGS. 1B and 1C, the magnetic field of the magnet 3 is shielded by the iron plate member 5 and does not reach the Hall IC 4, so that the magnetic field detected by the Hall IC 4 is minimized (zero).
[0024]
On the other hand, as shown in FIG. 3A, when the upper rail 2 is moved rearward (to the right in the drawing) with respect to the lower rail 1, the upper surface 1a of the lower rail 1 , The rotating member 6 rotates from the vertical posture, and the iron plate member 5 retreats from the gap between the magnet 3 and the Hall IC 4. Then, as shown in FIG. 3B, the magnetic field of the magnet 3 is transmitted through the Hall IC 4 without being blocked by the iron plate member 5, so that the magnetic field detected by the Hall IC 4 increases. Therefore, when a predetermined threshold value is set for the magnetic field detection value of the Hall IC 4 and the magnetic field detection value of the Hall IC 4 is larger than this threshold value, the upper rail 2 is located on the rear side with respect to the lower rail 1 and the Hall IC 4 Is smaller than the above threshold value, it can be detected that the upper rail 2 is located on the front side with respect to the lower rail 1.
[0025]
[Another embodiment]
In the above embodiment, the magnetic shielding member 5 is formed in a U-shape (U-shape) in plan view, but an L-shape as shown in FIG. 4 (A), or as shown in FIG. 4 (B). It may be formed in a simple single-sided (flat) type.
[0026]
In the above embodiment, the movable member 100 is configured as the rotating member 6, but as illustrated in FIG. 5, the movable member 100 may be configured as the linear moving member 8 that moves linearly. More specifically, the linear moving member 8 is constituted by an iron plate member having an inverted L-shaped upper portion 8b and a lower portion 8c bent in a J-shape. The elongated hole 8a is pivotally supported by a pin 12 attached to the sensor case 10, and a guide 13 for guiding a linear movement of the upper portion 8b in the vertical direction is attached to the sensor case 10.
[0027]
In the above configuration, when the upper rail 2 is located forward and the upper portion 1a of the lower rail 1 does not contact the lower side portion 8c of the linear moving member 8, the linear moving member 8 moves downward by its own weight and becomes longer. The upper end of the hole 8a is held at a position where it hits the pin 12. At this position, the tip of the upper portion 8b is located in the gap between the magnet 3 and the Hall IC 4. On the other hand, when the upper rail 2 moves rearward and the upper part 1a of the lower rail 1 comes into contact with the lower part 8c of the linear moving member 8, the linear moving member 8 moves upward and the tip of the upper part 8b is The magnetic field exits from the gap between the magnet 3 and the Hall IC 4 and passes therethrough. Therefore, when the linear moving member 8 is lowered and the tip of the upper portion 8b is located in the gap between the magnet 3 and the Hall IC 4, the linear moving member 8 is pushed up and the tip of the upper portion 8b is The position of the upper rail 2 with respect to the lower rail 1 can be detected based on the difference in the magnetic field detection value when not located in the gap between the Hall ICs 4.
[0028]
In the above-described embodiment, the movable member 100 (rotating member 6) is manufactured by molding the magnetic shielding member 5 made of an iron plate member integrally with resin. However, the movable member 100 (rotating member 6) may be integrally formed by using only an iron material. .
[0029]
In the above embodiment, the magnetic field generating unit 3, the magnetic field detecting unit 4, and the movable member 100 are provided on the moving member 2 (upper rail 2) side, and the movable member pressing means 200 (contact) is provided on the fixed member 1 (lower rail 1) side. Although the portion 1a) is provided, conversely, the movable member pressing means 200 is provided on the moving member 2 side, and the magnetic field generating section 3, the magnetic field detecting section 4, and the movable member 100 are provided on the fixed member 1 side. Similar effects can be obtained.
[0030]
In the above embodiment, the magnetic field generation unit 3 is configured by the magnet 3 and the magnetic field detection unit 4 is configured by the Hall IC 4. However, other various magnetic field generation units and magnetic field detection units can be used.
[0031]
In the above embodiment, the movable member pressing means 200 is constituted by the contact portion 1a which comes into contact with the movable member 100. In addition, various pressing forces including a force that can be pressed in a non-contact state such as a magnetic force are used. The movable member pressing means 200 can be configured.
[0032]
In the above embodiment, the movable member 100 is configured to use the action of gravity or magnetic force in order to return to the state located in the gap between the magnetic field generating unit 3 and the magnetic field detecting unit 4, but the elastic force of the coil spring or the like is used. May be used.
[0033]
In the above-described embodiment, the position detecting device of the present invention is applied to the vehicle seat position adjusting device. However, the position detecting device may be applied to a position detecting device between a fixed member and a moving member that relatively move, in addition to the vehicle seat position adjusting device. it can.
[Brief description of the drawings]
FIG. 1 is a front partial perspective view, a plan view, and a side view showing the configuration of a position detection device according to the present invention. FIG. 2 is a partial perspective view showing the structure of a movable member. FIG. FIG. 4 is a plan view showing a main part of a position detection device according to another embodiment. FIG. 5 is a front view and a plan view illustrating a position detection device according to another embodiment. Explanation of code]
DESCRIPTION OF SYMBOLS 1 Fixed member 1a Contact part 2 Moving member 3 Magnetic field generating part 4 Magnetic field detecting part 5 Magnetic shield 6 Rotating member 6a Intermediate part 6b One end side part 6c Other end side part 11 Position determining unit 100 Movable member 200 Movable member pressing means

Claims (4)

A magnetic field generation unit and a magnetic field detection unit that detects a magnetic field generated by the magnetic field generation unit are provided so as to be opposed to each other with a gap between one of a fixed member and a movable member movable with respect to the fixed member, and A movable member provided with a magnetic shield capable of entering and leaving the gap between the magnetic field generating unit and the magnetic field detecting unit,
In the other of the fixed member and the moving member, the moving state of the magnetic shield into and out of the gap between the magnetic field generating unit and the magnetic field detecting unit is changed with the movement of the moving member with respect to the fixed member. Movable member pressing means for pressing the movable member so as to be provided,
A position detection device provided with a position determination unit that determines a position of the moving member with respect to the fixed member based on detection information of the magnetic field detection unit. The movable member is formed as a rotating member rotatably supported by one of the fixed member and the moving member at an intermediate position, which includes the magnetic shield at one end side,
The position detecting device according to claim 1, wherein the movable member pressing unit is configured by a contact portion that contacts a portion on the other end side of the rotating member. The position detecting device according to claim 1, wherein the magnetic shield is made of a magnetic material that can be attracted by a magnetic field generated by the magnetic field generating unit. The position detection device according to any one of claims 1 to 3, wherein the movable member is formed so as to return to a state where the magnetic shield is positioned in a gap between the magnetic field generation unit and the magnetic field detection unit by gravity. .

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