JP2009098005A - Position detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detector capable of improving accuracy of a positional detection of a moving member. <P>SOLUTION: A magnetic head is configured such that a pair of magnets 5 are disposed between a pair of magnetic bodies 4 having facets facing each other, and the pair of magnetic bodies 4 and the pair of magnets 5 form a closed magnetic circuit. The moving member 3 moves the magnetic head in accordance with an operation value from an operating means 2. A magnetic detector 6 is disposed inside the closed magnetic circuit of the magnetic head and detects a change in a leakage field taking place inside the closed magnetic circuit along with a movement of the moving member 3. The moving member 3 and the magnetic head are made up separately. A cushioning member 4c is disposed in a gap C between the moving member 3 and the magnetic head. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a non-contact type position detector that detects an operation position (rotation angle) of an operation means mounted on various vehicles such as two-wheeled vehicles and automobiles with a magnetic detector composed of a Hall IC or the like. is there.

Conventionally, as this kind of non-contact type position detector, for example, the one described in Patent Document 1 is known. The position detector described in Patent Document 1 includes a first magnetic body formed in a substantially semicircular arc shape, and the first magnetic body disposed to face the first magnetic body so as to surround the first magnetic body. The direction of the magnetic field (N pole, S pole) disposed to form a closed magnetic circuit at both ends of the gap formed between the concentric second magnetic body and the first and second magnetic bodies is the same. Two permanent magnets, and a detection element such as a Hall element is arranged inside the closed magnetic circuit so as to detect a leakage magnetic field generated in the gap (inside the closed magnetic circuit). The detection element moves in the gap and detects the leakage magnetic field in response to rotation (rotation operation of the operation means), so that the detected object (the operation means) rotates from the output from the detection element. The moving angle was detected.
Japanese Examined Patent Publication No. 6-63769

  In the non-contact type position detector described in Patent Document 1, it is detected that the output change from the detection element has linearity (hereinafter referred to as linearity) over the entire range of the rotation angle of the operation means. Therefore, improvement of linearity is required. However, in the case of the position detector described in Patent Document 1, the first magnetic body and the second magnetic body located outside the first magnetic body are both formed in a substantially semicircular arc shape, and are closed by each magnetic body. Since the two permanent magnets constituting the magnetic circuit are arranged at both ends of the gap formed between the magnetic bodies, the magnetic bodies and the permanent magnets are manufactured at the time of manufacture. Due to variations in processing accuracy, the substantially semicircular arc-shaped magnetic bodies may be disposed in a state where they do not partially abut (surface contact) with the permanent magnets positioned therebetween.

  This is because the outer arc surface of the first magnetic body and one surface of each permanent magnet corresponding to the outer arc surface, and the other arc surface of the second magnetic body and the other surface of each permanent magnet facing it. Means that it does not adhere in all areas. For example, one of the two permanent magnets is in surface contact with the first and second magnetic bodies in the entire region, and the other permanent magnet is at least one of the first and second magnetic bodies. When the magnetic field of the leakage magnetic field that leaks into the closed magnetic circuit is partially in a non-contact state without surface contact in the entire region, the other permanent magnet in the non-contact state exists. The side becomes weaker than the one permanent magnet side where the non-contact state does not exist.

  Therefore, when the operation means is rotated over the entire rotation range of the operation means, the detection element is rotated in synchronization with the rotation of the operation means. The relationship (output characteristic) between the rotation angle of the operating means and the output (output voltage) detected by the detection element rotating in synchronization with the rotation of the operating means is the one permanent magnet side Due to the fact that the magnetic force of the leakage magnetic field is slightly different on the other permanent magnet side, there is a problem that output characteristics having linearity cannot be obtained and good detection accuracy cannot be obtained.

Therefore, the applicant of the present application has proposed as a Japanese Patent Application No. 2007-259581 a position detector in which the linearity is improved by gradually varying the width of the magnetic body provided in the magnetic head. However, in such a position detector, the moving member is provided with a magnetic source, and when the magnetic change of such a structure is detected by the magnetic detection element, the backlash in the thrust direction of the moving member is output as an error. Therefore, there is a problem that the accuracy of position detection deteriorates, and there is room for further improvement.
An object of this invention is to provide the position detection apparatus which can improve the position detection precision of a moving member.

  According to the first aspect of the present invention, a pair of magnets is disposed between a pair of magnetic bodies having opposing surfaces, and a closed magnetic circuit is formed by the pair of magnetic bodies and the pair of magnets. And a moving member that moves the magnetic head in accordance with the amount of operation of the operating means, and is disposed inside the closed magnetic circuit in the magnetic head. In the position detector including a magnetic detector that detects a change in the leakage magnetic field generated inside, the moving member and the magnetic head are separate.

  Further, according to the present invention, a buffer member is disposed between the moving member and the magnetic head.

  According to a third aspect of the present invention, the buffer member is a leaf spring.

  According to the first aspect of the present invention, by providing the moving member and the magnetic head separately, it is possible to prevent the magnetic head from transmitting backlash in the thrust direction of the moving member, and to improve the position detection accuracy. it can.

  According to the second aspect of the present invention, the buffer member is disposed between the moving member and the magnetic head, so that the gap between the moving member and the magnetic head can be compensated to prevent the magnetic head from moving in the moving direction. Detection accuracy can be improved.

  According to the third aspect of the present invention, since the buffer member is a leaf spring, the buffer member can be disposed even if the gap between the moving member and the magnetic head is narrow.

  Hereinafter, an embodiment in which the present invention is applied to a position detector that detects an operation amount (rotation angle) of an operation grip rotatably provided on a handle bar mounted on a motorcycle will be described with reference to the accompanying drawings. To do.

  The position detector includes an operation grip (operation means) 2 that is rotatably attached to the handle bar 1, a moving member 3 that rotates in synchronization with the rotation operation of the operation grip 2, and a pair of magnetic bodies 4. And a pair of magnets 5 which are embedded in the moving member 3 and form a closed magnetic circuit with the pair of magnetic bodies 4, and a leakage magnetic field which is disposed inside the closed magnetic circuit and which is generated inside the closed magnetic circuit is detected. For this reason, the magnetic detection body 6 is mainly composed of a magnetic detection body 6, a circuit board 7 on which the magnetic detection body 6 is mounted, and a frame body 8 for storing the magnetic body 4, the magnet 5, and the like.

  The operation grip 2 is made of a synthetic resin material such as polyacetal and is attached so as to cover the outer peripheral portion of the handlebar 1 of the two-wheeled vehicle located on the right side in FIG. In this case, since the operation grip 2 is formed integrally with the moving member 3, the moving member 3 rotates according to the operation amount of the operation grip 2. In addition, 2a is a collar part formed in the edge part of the operation grip 2 used as the frame 8 side.

  The moving member 3 is made of a synthetic resin material, is formed in a substantially flat ring shape surrounding the handle bar 1, is located in a cavity S formed between the handle bar 1 and the frame body 8, and the handle bar 1 is inserted therethrough. The ring part 3b which has the insertion part 3a to perform is provided. A pair of flange portions 3c and 3d are formed on the outer peripheral portion of the annular portion 3b at opposing positions. In addition, 3g is a contact surface which contacts the rotation control part mentioned later of the frame 8 when the operation grip 2 is returned to a normal position.

  The magnetic body 4 has a first magnetic body 4a made of a substantially flat plate, the same shape and the same thickness as the first magnetic body 4a, and has a predetermined constant interval from the first magnetic body 4a. And a second magnetic body 4b disposed so as to face each other. Each of the magnetic bodies 4a and 4b is made of a metal material such as iron and is formed in a substantially semi-annular shape by punching or the like. A leaf spring 4c, which is a buffer member made of a metal material formed in a substantially U shape, is welded to one end of the magnetic body 4.

The magnet 5 includes a first magnet 5a formed in a substantially disc shape (substantially cylindrical shape), and a second magnet 5b having the same shape and thickness as the first magnet 5, and the magnetic body 4 The magnetic bodies 4a and 4b are magnetically coupled and held by the magnetic force (the magnetic coupling force) of the magnets 5a and 5b. The magnets 5a and 5b and the magnetic bodies 4a and 4b constitute a magnetic head. This magnetic head is separate from the moving member 3, and the thrust of the moving member 3 in the thrust direction is not transmitted to the magnetic head. There is a slight gap C between one end of the magnetic body 4 and the flange portion 3c of the moving member, but this gap C has a leaf spring 4c as a buffer member to suppress backlash in the rotating direction of the magnetic head. ing.
The magnets 5a and 5b are made of a magnetic material such as samarium-cobalt, and are magnetized so that the N and S poles are opposite to each other between the magnetic bodies 4a and 4b. A closed magnetic circuit is formed by the bodies 4a and 4b and the magnets 5a and 5b.

  The magnetic detection body 6 is composed of a detection element such as a Hall IC or MR element (semiconductor magnetoresistive element), and is positioned between the magnetic bodies 4a and 4b, and magnetically couples the magnetic bodies 4a and 4b and the magnetic bodies 4a and 4b. The change in the leakage magnetic field accompanying the rotation of the magnets 5a and 5b is converted into an electric signal, and the electric signal is output to the outside through an electric cord described later. In addition, although the magnetic detection body 6 is arrange | positioned on the rotation track | orbit of the magnet 5, since it is arrange | positioned in the position which does not contact | abut with the rotating magnet 5, the magnet 5 and the magnetic detection body 6 are the same. It becomes the structure which does not contact.

  The circuit board 7 has a predetermined wiring pattern formed on a substantially rectangular substrate made of an insulating material such as glass epoxy, and is disposed below the magnetic body 4 and is not shown, which includes a magnetic detector 6 and a capacitor. Electronic parts and the like are electrically fixed by solder or the like. The circuit board 7 is provided with a plurality of electric cords 9 for transmitting the electric signal from the magnetic detector 6 to an engine control unit (not shown). Each electric cord 9 is soldered to a predetermined portion of the circuit board 7. Is electrically connected to the engine control unit.

  The frame body 8 is divided into an upper frame body 8a and a lower frame body 8b made of various metal materials such as non-magnetic metal materials such as aluminum or a synthetic resin material. The upper frame body 8a and the lower frame body The space region formed between the two members 8b forms a storage portion that stores each member such as the moving member 3, the magnetic body 4, the magnet 5, the magnetic detection body 6, and the circuit board 7. The upper frame 8a is mainly composed of a pair of opposed semicircular flat plate portions 8c and 8d and a curved wall portion 8e that closes the curved surface side opening of each of the semicircular flat plate portions 8c and 8d. Reference numeral 8f denotes a rotation restricting portion that restricts the rotation of the moving member 3 by the contact of the contact surface 3g of the moving member 3 when the rotation operation of the operation grip 2 is released, and this rotation restricting portion 8f. Is formed integrally with the curved wall 8e.

  On the other hand, the lower frame 8b includes a pair of flat plate portions 8g and 8h having a shape in which one end portion of a curved surface constituting a semicircle bulges outward, the curved surface in each of the flat plate portions 8g and 8h, and the curved surface. It is mainly comprised from the wall part 8i which blocks the opening of a continuous bulging part, and the circuit board 7 is accommodated in the said bulging part. Each frame 8a, 8b is fixed by appropriate fixing means such as a bolt (not shown) made of a nonmagnetic metal material.

  In the present embodiment, the moving member 3 and the magnetic head are separated from each other, and it is possible to improve the position detection accuracy so that the magnetic head does not transmit backlash in the thrust direction of the moving member 3, and By disposing the leaf spring 4c between the moving member 3 and the magnetic head, it is possible to compensate for the gap C between the moving member 3 and the magnetic head, and to suppress backlash in the rotating direction of the magnetic head. In addition, since the pair of magnetic bodies 4 are formed into a flat plate shape by punching, and the pair of magnets 5 interposed between the pair of magnetic bodies 4 are formed in a cylindrical shape, the magnetic body 4 and the magnet 5 Can be manufactured easily, and cost increase can be suppressed.

1 is an overview diagram of an embodiment of the present invention. Sectional drawing of embodiment same as the above. Explanatory drawing of the magnetic head of embodiment same as the above.

Explanation of symbols

1 Handlebar 2 Operating grip (operating means)
2c Projection 3 Moving member 4 Magnetic body 4a First magnetic body 4b Second magnetic body 4c Leaf spring (buffer member)
DESCRIPTION OF SYMBOLS 5 Magnet 5a 1st magnet 5b 2nd magnet 6 Magnetic detection body 7 Circuit board 8 Frame body 9 Holding body C Crevice

Claims (3)

  A magnetic head in which a pair of magnets are arranged between a pair of magnetic bodies having opposing surfaces, and a closed magnetic circuit is formed by the pair of magnetic bodies and the pair of magnets, and according to the operation amount of the operating means A moving member that moves the magnetic head, and a magnetic detector that is disposed inside the closed magnetic circuit in the magnetic head and detects a change in a leakage magnetic field generated in the closed magnetic circuit as the moving member moves. A position detector comprising: the moving member and the magnetic head separately.   The position detector according to claim 1, wherein a buffer member is disposed between the moving member and the magnetic head.   The position detector according to claim 2, wherein the buffer member is a leaf spring.

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