JP2002337575A - Seat position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat position sensor capable of using a generalized magnet, inexpensive, and having high reliability by shortening the distance between the magnet and a magneto-electric converting element such as a Hall IC. SOLUTION: This seat position sensor is provided with a casing K including a seat and fitted to movable members 11, 12 or a fixing member 13, a magneto-electric converting element 3 held in the casing K, and the magnet 7 provided opposite to the magneto-electric converting element 3. The magnet 7 is provided on a rotator 6 rotatably held in the casing K, whereby when the movable members 11, 12 are moved, the rotator 6 is rotated to shift the position of the magnet 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat position sensor used for detecting the position of a seat in an automobile or the like, and used for controlling expansion of an air bag and the like.

[0002]

2. Description of the Related Art Referring to the drawings of a conventional seat position sensor, FIG. 8 is a perspective view showing a state where a conventional seat position sensor is mounted, and FIG. 9 is an enlarged view showing a state where a conventional seat position sensor is mounted. FIG. 10 is a perspective view, FIG. 10 is a cross-sectional view of a main part showing a state where a conventional seat position sensor is attached, and FIG. 11 is a cross-sectional view of a main part of a conventional seat position sensor.

A conventional seat position sensor will be described with reference to FIGS. 8 to 11. The first rail 51 is formed by bending a metal plate into a substantially U-shape. A pair is fixed. Shielding plate 54
Is formed by bending a metal plate into an L-shape, and has an elongated flat base portion 54a and a side wall portion 54b formed by bending downward from an end of the base portion 54a. Is fixed to the first rail 51, and the shielding plate 54 is slidable together with the first rail 51.

The second rail 52 is formed by bending a metal plate into a substantially U-shape, and is combined with the first rail 51 so as to form a reverse convex shape as shown in FIG. . The second rail 52 is fixed to a floor in a vehicle cabin by holding legs 53 bent in an L-shape.

[0005] The seat position sensor 55 is made of a synthetic resin molded article, and has a base 55a formed in a U-shape.
A rectangular magnet 56 buried in the first side wall 55b of the base 55a and a second magnet 55c buried in the second side wall 55c formed facing the first side wall 55b and facing the magnet 56. And a rectangular Hall IC 57. The magnet 56 is made of, for example, several hundred mT of samarium, cobalt, or the like.
(Militesla) is used. The seat position sensor 55 is attached to the second rail 52 by a stay 58.

When the seat position sensor 55 is attached, the gap 55 between the first and second side walls 55b and 55c is provided.
When the shielding plate 54 is located within the gap 55d, the magnetic field formed by the magnet 56 is blocked by the shielding plate 54, and the magnetic flux density received by the Hall IC 57 decreases. And Hall IC5
The switching of the switch No. 7 is performed.

The conventional seat position sensor 55 is in the above-described configuration and mounted state. Next, the operation thereof will be described. When the seat 60 moves, the shielding plate 54 moves in and out of the gap 55d of the seat position sensor 55.
The switch of the Hall IC 57 is switched, and the switching of the signal changes, for example, the outflow of gas when an airbag (not shown) is inflated, thereby adjusting the airbag.

[0008]

The conventional seat position sensor 55 has the above-described configuration, mounting state, and operation. However, since there is a gap 55d between the magnet 56 and the Hall IC 57, it is inevitable between the two. Since the distance is increased, the material of the magnet 56 must be made very strong, and there is a problem that it is expensive. Further, since the magnet 56 is very strong, metal scraps and the like easily adhere to the magnet 56,
A change in the magnetic field may occur, and switching of the Hall IC 57 may not be performed at an appropriate position.

The seat position sensor according to the present invention can use general-purpose magnets by reducing the distance between the magnet and a magnetoelectric conversion element such as a Hall IC, and can be used at low cost.
It is another object of the present invention to provide a highly reliable seat position sensor.

[0010]

As a first means for solving the above problems, a seat position sensor according to the present invention is mounted on a movable member including a sheet or a fixed member which movably holds the movable member. Provided, a magnetoelectric conversion element held by the casing, and a magnet provided to face the magnetoelectric conversion element, wherein the magnet is provided on a rotating body rotatably held by the casing, When the movable member moves, the rotating body rotates and the position of the magnet moves.

As a second solution, the casing of the seat position sensor according to the present invention is provided with an urging member for urging the rotating body in a rotational direction, and the rotating body is rotated by the urging member. It is configured to be held without play in the direction.

As a third solution, the movable member of the seat position sensor of the present invention comprises a seat and a first rail attached to the seat, and the casing is attached to the first rail. The first rail moves with the movement of the seat, so that the rotating body rotates.

As a fourth solution, the fixing member of the seat position sensor according to the present invention is constituted by a second rail combined with the first rail, and the rotating body sandwiches a rotation center from the magnet. The rotating body is urged by the urging member so that the engaging portion protrudes from the casing in an initial state, and the casing moves with the movement of the sheet. Then, the engaging portion of the rotating body is pressed by the second rail, and the rotating body rotates to move the position of the magnet.

As a fifth solution means, the casing of the seat position sensor of the present invention has a storage portion for storing the rotating body, and the storage portion is opened outward in a radial direction of the rotating body. An opening is provided, and the engaging portion protrudes outward from the opening.

As a sixth solution, the opening of the seat position sensor of the present invention is configured to open to the lower side of the seat.

As a seventh solution, the casing of the seat position sensor according to the present invention has a contact portion formed so as to close a part of the opening, and the initial state of the rotating body is provided. In this configuration, the rotating body is urged by the urging member and is in contact with the contact portion.

As an eighth solution, the urging member of the seat position sensor of the present invention has a winding part and a set of arms, and the winding part is held by the casing. At the same time, the set of arm portions is locked to the contact portion and the rotating body, and the rotating body is biased in the rotational direction by the biasing member, and in the initial state, by the biasing member. The configuration is such that the rotation of the rotating body is in contact with the end of the contact portion and is regulated.

As a ninth solution means, a wall portion is formed in the casing of the seat position sensor of the present invention at a position facing the opening of the storage portion, and the magnetoelectric conversion element is separated from the magnet by the magnet. It was configured to be provided on the opposite side across the wall.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings of the seat position sensor of the present invention, FIG. 1 is a front view of the seat position sensor of the present invention, FIG. 2 is a perspective view of the seat position sensor of the present invention, and FIG. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1, FIG. 5 is a perspective view showing an attached state of the seat position sensor of the present invention, and FIGS. FIG. 4 is an explanatory diagram for explaining an operation of a seat position sensor.

The seat position sensor of the present invention is shown in FIGS.
Referring to FIG. 7, the housing 1 is formed of a rectangular synthetic resin molded product, and includes a rectangular base 1a and the base 1a.
A concave portion 1b formed to extend in the longitudinal direction on the side surface
Is provided in the vicinity of the concave portion 1b and the concave portion 1b
And a storage portion 1c formed of a concave portion which is shorter in the longitudinal direction. Further, a wall 1d is formed between the storage section 1c and the recess 1b, and the wall 1d has a recess 1k, and the thickness of the portion is reduced. In addition, storage section 1
c has an opening 1e that opens downward, and this opening 1e
Is a contact portion 1 extending in the longitudinal direction at the outer edge of the base 1a.
f is partially closed. The inner wall surface of the concave portion 1b is provided with a locking portion 1g made of a concave streak.
At the eccentric position of the storage portion 1c, a shaft portion 1h protruding laterally is formed.

The substrate 2 is formed of a rectangular insulating substrate, and is fixed in a state of being fitted to the locking portion 1g of the concave portion 1b.
The Hall IC 3 is formed of an IC on which various electric components such as a Hall element, an amplifier, and a comparator are mounted, has a substantially rectangular shape, and has an L-shaped terminal 3a attached thereto. This Hall IC 3 is arranged on the lower surface of the substrate 2, and the terminals 3 a are soldered to the substrate 2.

The yoke 4 has a rectangular shape made of soft iron,
It is fitted into a recess formed in the base 1a forming the recess 1b, and is fixed to the housing 1 by fixing means such as an adhesive.

The lead portion 5 includes a lead wire 5a and a rubber bush 5b having a through hole through which the lead wire 5a passes.
One end of the lead wire 5a is connected to the substrate 2,
The rubber bush 5b is fitted into the base 1a of the housing 1,
The lead wire 5a extends outward.

The rotating body 6 is made of a synthetic resin molded product.
It has a base 6a having a substantially rectangular shape, a first recess 6b formed near the center of the base 6a, and a second recess 6c formed near the first recess 6b. Also,
A cylindrical tubular portion 6d is formed laterally from an eccentric position shifted from the center of the first concave portion 6b, and the tubular portion 6d has a through hole 6e penetrating the base 6a in the left-right direction. An arc-shaped projection 6k is formed near the edge of the first recess 6b, and the projection 6k has a fitting portion 6f formed of a bow-shaped recess, and a pair of opposite ends of the fitting portion 6f. Is formed so that the snap claw 6g protrudes.
An engaging portion 6h bent in an L-shape is provided near g.

The magnet 7 is made of a general purpose magnet of several tens mT (millitesla) such as ferrite, has a curved shape, is embedded in the fitting portion 6f of the rotating body 6, and is fixed by a snap claw 6g. .

The rotating body 6 having such a structure is provided with a cylindrical portion 6.
The shaft 1h of the housing 1 is inserted into the through hole 6e of d, and is rotatably held by the housing 1. Further, the pin 8 for retaining is inserted into the shaft portion 1h, and the tip of the pin 8 is caulked, so that the rotating body 6 is securely fixed. When the rotating body 6 rotates, the magnetic flux density detected by the Hall IC 3 changes, and switching is performed when the Hall IC reaches a given magnetic flux density. Further, since the yoke 4 is disposed so as to face the magnet 7, the magnetic field is attracted to the yoke 4 side, so that the vertical component of the line of magnetic force becomes stronger. Further, a recess 1k is formed in a portion between the magnet 7 and the Hall IC 3 in the wall portion 1d, and the distance between the magnet 7 and the Hall IC 3 is short. Further, a storage unit 1c for storing the magnet 7
And the concave portion 1b for accommodating the Hall IC 3 can be made a different space, so that even if foreign matter enters through the opening 1e, it does not adhere to the Hall IC 3 or the circuit portion, and there is no danger of short circuit.

The torsion spring 9 serving as an urging member includes a winding portion 9a.
And first arm portions 9b extending from both ends of the winding portion 9a
And a second arm 9c. This torsion spring 9 is held in a state where the rotating body 6 is urged in the rotating direction,
The winding part 9a is inserted into the outer periphery of the cylindrical part 6d of the rotating body 6, and the first arm part 9b is locked between the locking part 6h and the protruding part 6k of the rotating body 6, and The arm portion 9c is housed in an elongated recess formed in the contact portion 1f of the housing 1, and in the assembled state, the first and second arm portions 9b and 9c are always bent in the approaching direction. , In a locked state.

The rotating body 6 is urged in the rotating direction by the torsion spring 9 incorporated in this manner, and the position is determined in the initial state. That is, the protruding portion 6k is urged by the first arm portion 9b, a rotational load is applied to the rotating body 9, and the edge of the rotating body 6 located near the winding portion 9a is positioned at the end of the contact portion 1f. It is in a state in which it is in contact with the portion 1m and further rotation is restricted. In this initial state, the engaging portion 6m located on the opposite side of the magnet 7 with the cylindrical portion 6d serving as the rotation center interposed therebetween projects outward from the opening 1e. And the rotating body 6
Is pressed, the rotating body 6 rotates in a direction to fit in the storage portion 1c against the urging force of the torsion spring 9, and when the pressing force is released, the contact portion 1f is pressed by the urging force of the torsion spring 9. The rotating body 6 is returned until it comes into contact with the end 1m of the rotating member 6 to return to the initial state. Since the torsion spring 9 is provided as described above, the rotating body 6 is always in tension, so that the rotating body 6 is always in a state of no backlash in the rotating direction.

The cover member 10 is formed by bending a thin metal plate. The base member 10a is formed by bending a flat plate into a concave shape. The base member 10a extends in a direction away from the end of the base member 10a and extends through the base member 10a. And a pair of mounting pieces 10b having holes 10c. The cover member 10 is attached to the housing 1 so that the base 10a surrounds the housing 1, and a snap claw 1n formed on the housing 1 is snap-bonded to the base 10a to be securely fixed to the housing 1. The cover K and the housing 1 constitute a casing K.

The seat position sensor S of the present invention has the above-described structure. Next, the mounting state and operation of the seat position sensor S will be described with reference to FIGS. 5 to 7. The seat 11 includes a seat plate 11a and a backrest 11b. And is installed in the interior of a car. The first rail 12 is formed by laminating two L-shaped elongated metal members, and is formed by bending a base portion 12a extending in a vertical direction and a U-shape from a lower end portion of the base portion 12a. The first rail 1 has a pair of bent portions 12b.
A pair 2 is attached to the lower surface of the seat plate 11a. The seat 11 and the first rail 12 constitute a movable member. Then, the base 12 of one of the first rails 12
A bolt (not shown) is inserted into the through hole 10c of the cover member 10 of the seat position sensor S of the present invention on the side wall a, and is fastened with a nut (not shown) to fix the seat position sensor S. ing. When the seat position sensor S is attached in this manner, the engaging portion 6m of the rotating body 6 projects below the seat 11.

The second rail 13 is made of a U-shaped elongated metal material, and has a flat base 13a and a base 13a.
13 formed by bending upward from both ends of
b, and the second rail 13 is fixed to the floor of the interior of the vehicle by a pair of desired fixing means, and forms a fixing member.

The second rail 13 having such a structure includes:
The first rail 12 is movably assembled, and this assembling is performed by combining the bent portions 12b and 13b. Then, the seat 11 is slidably held on the second rail 13.

When the seat 11 slides, the seat position sensor S moves with the movement, and as shown in FIG. 6, an engaging portion 6m protruding toward the floor surface side.
However, as shown in FIG. 7, the rotating body 6 is rotated by rotating the rotating body 6 by abutting against the distal end portion 13 c of the second rail 13 and riding on the top surface 13 d of the bent piece 13 b. 7
Moves. When the position of the magnet 7 moves, the output of the Hall IC 3 is switched, the signal from the drawer 5 is switched, and the amount of gas that flows out when the airbag (not shown) is inflated is changed. Is adjusted. At this time, the torsion spring 9 is connected to the first and second arm portions 9b and 9c.
Are shrunk closer to each other. Note that once the engaging portion 6m rides on the top surface 13d, even if the seat 11 moves, the engaging portion 6m only slides on the top surface 13d.
No further rotation of the rotating body 6 is performed. In the initial state where the second rail 13 does not contact the rotating body 6, the engaging portion 6m of the rotating body 6 is inclined to the opposite side (left side in FIG. 7) to the second rail 13. When the tip 13c abuts from the right in FIG. 7, it rotates smoothly.

Next, when the seat 11 slides in the opposite direction and the engaging portion 6m is located at the tip 13c of the second rail 13, the rotating body 6 is rotated by the urging force of the torsion spring 9, and the initial state is established. Return to. When the position of the magnet 7 moves, the output of the Hall IC 3 is switched, the signal from the drawer 5 is switched, and the outflow amount of gas when the airbag (not shown) is inflated is changed. Then, adjustment of the airbag is performed.

Next, the assembly process of the seat position sensor of the present invention will be described. The board 1 on which the Hall IC 3 and the like are mounted from the open side of the concave portion 1b of the housing 1 to which the yoke 4 is attached, that is, the right side shown in FIG.
Insert using g as a guide. In addition, the rubber bush 5b is also pressed into the cutout provided at the upper right of FIG. Then, the rotating body 6 holding the magnet 7 is inserted from the open side into the shaft portion 1h provided in the housing 1, the pin 8 is inserted, and the tip is crimped. Finally, the cover member 10 is attached so as to cover the open side of the housing 1, and the assembly is completed. As described above, since the rotating body 6, the substrate 2, and the rubber bush 5b can be incorporated into the housing 1 from the open side (the right side in FIG. 4) of the housing 1,
Very good assemblability.

Although the seat position sensor S of the present invention has the above-described configuration, mounting state, and operation, it is needless to say that the present invention is not limited to the above description. The engaging portion 6 may be protruded upward. In this case, it is necessary that the engaging portion can be pressed by the rail. In addition, the seat position sensor S may be attached to a fixed member, that is, the second rail 13.
Will be pressed. In the embodiment, the Hall IC 3 is provided as the magnetoelectric conversion element.
sistence), GMR (Giant Magneto Resistence) or the like may be used.

In this embodiment, the engaging portion 6m is made to protrude from the housing 1, and the engaging portion 6m
3c are in contact with each other.
m, a push rod protruding in the sliding direction is provided on the second rail 13, a through hole is provided in the housing 1 to allow the push rod to be inserted, and the push rod rotates as the sheet 11 moves. 6
May be pressed so that the rotating body 6 rotates.

[0038]

The magnet of the seat position sensor of the present invention is provided on a rotating body rotatably held in a casing, and when the movable member moves, the rotating body rotates to move the position of the magnet. Since the magnetic flux density detected by the magneto-electric conversion element changes due to the rotation of the rotating body, there is no need for an intervening element that changes the magnetic flux density between the magnet and the magneto-electric conversion element. Since the length can be shortened, a relatively weak and inexpensive magnet can be used, and an inexpensive seat position sensor can be provided. Further, since the magnet can be weakened, metal scraps and the like do not adhere to the magnet, the performance is maintained, and the reliability can be improved.

The casing of the seat position sensor of the present invention is provided with an urging member for urging the rotating body in the rotating direction, and the rotating body is held by the urging member in a state where there is no play in the rotating direction. With this configuration, the rotation of the rotating body can be stabilized, so that a highly reliable seat position sensor in which a switch is switched at a predetermined position can be provided.

The movable member of the seat position sensor according to the present invention comprises a seat and a first member attached to the seat.
The casing is attached to the first rail, and the first rail moves with the movement of the seat, so that the rotating body rotates. Therefore, the rotation is performed using the movement of the seat. Since the structure for rotating the body can be simply configured, a seat position sensor that can be operated with a simple structure can be provided.

Further, as the seat of the seat position sensor of the present invention moves, the casing moves, and the engaging portion of the rotating body is pressed by the second rail, and the rotating body rotates to move the position of the magnet. With this configuration, the structure for rotating the rotating body by using the movement of the seat can be simply configured, so that a seat position sensor that can be operated with a simple structure can be provided.

Further, the casing of the seat position sensor of the present invention has a storage portion for storing the rotating body, and the storage portion has an opening that opens outward in the radial direction of the rotating body. Because the engagement part is configured to protrude outward,
Since the rotating body can be stored in the storage section, a thin and small seat position sensor can be provided.

Further, since the opening of the seat position sensor of the present invention is open to the lower side of the sheet, it is difficult for dust and dirt to enter, so that the dustproof effect is enhanced and the reliability is good. A simple seat position sensor can be provided.

Further, the casing of the seat position sensor of the present invention has a contact portion formed so as to close a part of the opening, and in the initial state of the rotating body, the rotating body is attached to the urging member. Because it is configured to be in contact with the contact part by being urged,
Since the position of the rotating body can be regulated with a simple configuration,
A seat position sensor having good mass productivity can be provided.

Further, the biasing member of the seat position sensor of the present invention has a winding portion and a set of arms, and the winding portion is held by the casing and the set of arms is in contact. The rotating body is urged in the rotational direction by the urging member, and the rotation of the rotating body is restricted by the urging member in contact with the end of the contact portion in the initial state. In this configuration, the urging member can be easily attached, the rotating body can be restricted with a simple configuration, and a seat position sensor with good assemblability and mass productivity can be provided. .

In the casing of the seat position sensor according to the present invention, a wall is formed at a position facing the opening of the storage portion, and a magnetoelectric conversion element is provided on the opposite side of the magnet from the magnet. With this configuration, dust and the like that enter from the opening do not enter the magnetoelectric conversion element due to the presence of the wall, so that a dust-proof effect is enhanced and a highly reliable seat position sensor can be provided. .

[Brief description of the drawings]

FIG. 1 is a front view of a seat position sensor according to the present invention.

FIG. 2 is a perspective view of a seat position sensor of the present invention.

FIG. 3 is a sectional view of a main part of the seat position sensor of the present invention.

FIG. 4 is a sectional view taken along line 4-4 in FIG. 1;

FIG. 5 is a perspective view showing an attached state of the seat position sensor of the present invention.

FIG. 6 is an explanatory diagram for explaining the operation of the seat position sensor of the present invention.

FIG. 7 is an explanatory diagram for explaining the operation of the seat position sensor of the present invention.

FIG. 8 is a perspective view showing a state where a conventional seat position sensor is attached.

FIG. 9 is an enlarged perspective view showing a state where a conventional seat position sensor is attached.

FIG. 10 is a sectional view of a main part showing a state where a conventional seat position sensor is attached.

FIG. 11 is a sectional view of a main part of a conventional seat position sensor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 housing 1a base 1b recess 1c storage 1d wall 1e opening 1f abutment 1g locking 1h shaft 1k recess 1m end 1n snap claw 2 substrate 3 hole IC 4 yoke 5 drawer 6 rotating body 6a Base 6b First concave portion 6c Second concave portion 6d Tube portion 6e Through hole 6f Fitting portion 6g Snap claw 6h Locking portion 6k Projecting portion 6m Engaging portion 7 Magnet 8 Pin 9 Torsion spring 9a Winding portion 9b First arm Part 9c Second arm part 10 Cover member 11 Seat (movable member) 12 First rail (movable member) 13 Second rail (fixed member) K Casing S Seat position sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01D 5/245 G01D 5/245 V G01R 33/02 G01R 33/02 Q F term (Reference) 2F077 AA41 AA46 AA49 CC02 JJ08 JJ23 NN18 PP12 VV02 VV31 VV33 2G017 AA00 AB07 AD53 3B087 DE08 DE10 3D054 EE10

Claims (9)

[Claims] 1. A casing attached to a movable member including a sheet or a fixed member movably holding the movable member, a magnetoelectric conversion element held by the casing, and provided facing the magnetoelectric conversion element. The magnet is provided on a rotating body rotatably held by the casing, and when the movable member moves, the rotating body rotates to move the position of the magnet. Characteristic seat position sensor. 2. The apparatus according to claim 1, wherein the casing is provided with an urging member for urging the rotating body in a rotating direction, and the rotating body is held by the urging member without play in the rotating direction. The seat position sensor according to claim 1. 3. The movable member includes a seat and a first rail attached to the seat, the casing is attached to the first rail, and the first rail is moved as the seat moves. The seat position sensor according to claim 1, wherein the rotating body is rotated by moving the body. 4. The fixed member is composed of a second rail combined with the first rail, and the rotating body has an engaging portion on the opposite side of the magnet with respect to a center of rotation. In the initial state, the urging member is urged by the urging member so that the engagement portion protrudes from the casing. With the movement of the sheet, the casing moves,
4. The seat position sensor according to claim 3, wherein the engaging portion of the rotating body is pressed by the second rail, and the rotating body rotates to move the position of the magnet. 5. 5. The casing has a storage section for storing the rotating body, the storage section has an opening that opens outward in a radial direction of the rotating body, and the engaging section extends from the opening. The seat position sensor according to claim 4, wherein the projection protrudes outward. 6. The seat position sensor according to claim 5, wherein the opening is open to a lower side of the seat. 7. The casing has a contact portion formed so as to close a part of the opening, and in the initial state of the rotating body, the rotating body is urged by the urging member. The seat position sensor according to claim 5, wherein the seat position sensor is in contact with the contact portion. 8. The urging member has a winding part and a set of arms, the winding part is held by the casing, and the set of arms is connected to the contact part. Locked to the rotating body, the rotating body is urged in the rotating direction by the urging member, and in the initial state, the rotation of the rotating body is rotated by the urging member to an end of the contact portion. The seat position sensor according to claim 7, wherein the seat position sensor is in a state of being abutted and regulated. 9. A wall is formed in the casing at a position facing the opening of the storage section, and the magnetoelectric conversion element is provided on an opposite side of the magnet with the wall separated from the magnet. The seat position sensor according to any one of claims 5 to 8, wherein: