JP2002071308A - Non-contact position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the output accuracy of an output signal corresponding to the location of a movable metallic body. SOLUTION: The non-contact position sensor is provided with a sensor coil 5 and the movable metal body with a part to be detected, which goes in and out of the center through-hole of the sensor coil 5, along the axial direction of the sensor coil to change the occupancy amount to a magnetic path. By driving and exciting the sensor coil 5 to generate a high-frequency modulating magnetic field and detecting the magnetic changes of the sensor coil 5, which occurs according to the coming-in and -out of the part to be detected, the non- contact position sensor detects the location of the movable metal body along the axial direction. In the non-contact position sensor, the sensor coil 5 is provided with a constitution, in which the number of windings is relatively larger close to both ends in the axial direction in a unit of length along the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type position sensor used for an AT sensor, a neutral sensor, and the like used in an automobile transmission.

[0002]

2. Description of the Related Art Conventionally, as a non-contact type position sensor of this type, there is one disclosed in Japanese Patent Application Laid-Open No. 2000-186903. As shown in FIG. 22, a sensor coil 101 in which a central axis is curved in an arc shape and whose coil wire is uniformly wound so as to be driven to oscillate by an external circuit to generate a high-frequency magnetic field, along an axial direction. Sensor coil 101
Metal shaft (movable metal body) 102 and sensor coil 10 whose occupancy with respect to the magnetic path changes in and out of the center through hole
Drive coil 1 to generate a high-frequency modulated magnetic field and generate a sensor coil
There is provided a sensor circuit 103 which generates an output signal corresponding to the position of the metal shaft 102 by detecting a magnetic change (impedance change) of one.

The metal shaft 102 is formed in an arc shape, moves with the rotation of the rotating shaft that rotates in conjunction with the object to be detected, and moves into and out of the center through hole of the sensor coil 101. FIG. 23 schematically shows a state where the sensor coil 101 enters and exits the center through hole.

[0004]

In the above-described conventional non-contact position sensor, since the sensor coil 101 is designed to have a predetermined length along the axial direction for miniaturization, a metal shaft is required. In order to obtain an output signal in accordance with the amount of movement of the metal coil 102, the metal shaft 102 enters the central through hole up to near both ends in the axial direction of the sensor coil 101.

On the other hand, since the magnetic field is reduced near the axial ends of the sensor coil 101 as compared with the central portion in the axial direction, the amount of change in the magnetic flux flowing through the metal shaft 102 is reduced. As a result, near both ends of the sensor coil 101, as shown in FIG. 24, the output accuracy of the output signal corresponding to the rotation angle of the rotating shaft, that is, the position of the metal shaft (movable metal body) 102 (linearity of the output signal). However, there is a problem that the temperature is reduced.

The present invention has been made in view of the above points, and an object of the present invention is to provide a contact type position sensor having a high output accuracy of an output signal corresponding to the position of a movable metal body. is there.

[0007]

According to a first aspect of the present invention, there is provided a non-contact type position sensor.
A sensor coil, and a movable metal body having a detected part whose occupancy with respect to a magnetic path changes in and out of a center through hole of the sensor coil along the axial direction of the sensor coil, and drives and excites the sensor coil. A non-contact type position sensor for detecting a position of a movable metal body along an axial direction by detecting a magnetic change of a sensor coil generated in response to entrance and exit of a detected portion by generating a high-frequency modulated magnetic field. The sensor coil is configured such that the number of turns in a unit length along the axial direction is relatively increased near both ends in the axial direction.

According to a second aspect of the present invention, in the non-contact position sensor according to the first aspect, the sensor coil gradually increases the number of turns in a unit length along the axial direction toward the both ends. It has many configurations.

According to a third aspect of the present invention, there is provided the non-contact position sensor according to the first aspect, further comprising a partition for partitioning a winding space along the axial direction, wherein the sensor coil has both ends in the axial direction. In the closer winding space, the number of windings per unit length along the axial direction is relatively increased.

According to a fourth aspect of the present invention, there is provided a non-contact position sensor, comprising: a movable metal having a sensor coil; A movable metal body along the axial direction by driving and exciting the sensor coil to generate a high-frequency modulated magnetic field and detecting a magnetic change of the sensor coil generated in accordance with the entrance and exit of the detected part. In the non-contact type position sensor for detecting a position, the detected portion has a configuration in which both ends in the direction of entering and exiting the sensor coil are relatively thick.

According to a fifth aspect of the present invention, in the non-contact type position sensor according to the fourth aspect, the detected portion is gradually thicker toward both ends.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

Reference numeral 1 denotes a movable metal body, which is made of a magnetic metal material. It consists of parts 1b, 1b. The two detected parts 1b, 1b are each formed in a substantially quarter-circular arc shape so as to enter or leave one of a pair of sensor coils 5 described later, and are integrated near the connection with the embedded part 1a. ing.

Reference numeral 2 denotes a movable frame, which has a substantially cylindrical shape, and an embedded portion 1a of the movable metal body 1 is integrally formed with a side wall portion. A rotating shaft (not shown) that rotates in conjunction with the automatic transmission is fixedly penetrated through a through hole 2 a provided along the axial direction of the movable frame 2, and the movable shaft is movable in accordance with the rotation of the rotating shaft. The metal body 1 rotates around the rotating shaft.

A coil bobbin 3 is provided in a pair, each of which has a central axis curved in an arc shape and is provided at both ends of the winding drum 3b provided with through holes 3a along the axial direction. It consists of the flange parts 3c and 3d. This coil bobbin 3
A conductive metal plate 4A is integrally formed with the one end flange 3c, and the conductive metal plate 4A is appropriately cut after the integral formation to form the coil terminal 4. This coil terminal 4
Is connected to a sensor coil 5 described later.

Reference numeral 5 denotes a sensor coil, and as shown in the schematic diagram of FIG. 1, the number of turns in the unit length along the axial direction becomes relatively large near both ends in the axial direction on the winding drum portion of the coil bobbin 3. Thus, the coil wire is wound. This sensor coil 5
As described above, the detected portion 1b of the movable metal body 1 enters the central through-hole, and in the most penetrated state, both ends of the detected portion 1b are located near both end openings.

Reference numeral 6 denotes a housing, which comprises a case 6a having an opening on one surface and a cover 6b attached to the opening side of the case 6a. When the coil bobbin 3 and the sensor coil 5 are housed inside the housing 6a. With movable metal body 1
The movable frame 2 integrally formed with the embedded portion 1a of the
It is arranged rotatably in a state that it partially protrudes from.
An O-ring 7 is interposed between the movable frame 2 and the housing 6 so that they are in close contact with each other. Also,
The housing 6 houses a circuit board 8 on which an electronic circuit such as an oscillation drive circuit is mounted, and a connector terminal 9 is connected to the circuit board 8.

Next, the operation of this device will be described. When the rotating shaft is rotated in a state where the sensor coil 5 is driven to oscillate by the oscillation driving circuit to generate a high-frequency magnetic field, the movable metal body 1 rotates about the rotating shaft and one of the movable metal bodies 1 is rotated. The detected portion 1b of the sensor coil 5 is inserted into the through hole 3a of one of the coil bobbins 3, and the other detected portion 1b is protruded from the through hole 3a of the other coil bobbin 3. , The occupancy of each of the detected parts 1b with respect to the magnetic path changes.
The magnetic change (impedance change) of the sensor coil 5 occurs according to the movement of the detected portion 1b.
Therefore, by detecting the magnetic change, the position of the movable metal member 1 can be detected, and an output signal corresponding to the position of the movable metal member 1 can be output from the connector terminal 8.

In such a non-contact type position sensor, the number of turns per unit length along the axial direction of the sensor coil 5 is relatively increased near both ends in the axial direction. The magnetic field near both ends in the axial direction of the sensor coil 5 increases as compared with the case where the number of turns in the length is made uniform, and the magnetic field near both ends in the axial direction is substantially the same as the magnetic field in the central part in the axial direction. Degree. Therefore, even if both ends of the movable metal member 1 enter near both ends in the axial direction of the sensor coil 5, the output accuracy (linearity of the output signal) of the output signal corresponding to the position of the movable metal member 1 can be increased.

Next, a second embodiment of the present invention will be described with reference to the schematic diagram of FIG. Only different points from the first embodiment will be described. This embodiment is basically the same as the first embodiment, but the sensor coil 5 has a configuration in which the number of turns per unit length along the axial direction is gradually increased toward both ends.

In such a non-contact type position sensor, since the magnetic field gradually decreases toward both ends in the sensor coil 5, the number of turns in a unit length along the axial direction gradually increases toward the both ends. By increasing, the output accuracy of the output signal corresponding to the position of the movable metal body 1 can be made higher than in the first embodiment.

Next, a third embodiment of the present invention will be described with reference to the schematic diagram of FIG. Only different points from the first embodiment will be described. This embodiment is basically the same as the first embodiment. However, as shown in FIG. 2A, a partition 3e for partitioning a winding space along an axial direction is formed by a winding drum 3b of a coil bobbin 3. The sensor coil 5 has a configuration in which the number of turns per unit length along the axial direction is relatively increased in the winding space near both ends in the axial direction, as shown in FIG.

In the non-contact position sensor, in addition to the effect of the first embodiment, the number of windings per unit length along the axial direction is managed for each winding space along the axial direction. And variations in the number of turns can be reduced.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. Only different points from the first embodiment will be described. In the first embodiment, the number of turns in the unit length along the axial direction of the sensor coil 5 is relatively increased near both ends in the axial direction. By making the outer portion connected to the portion 1a closer to both ends in the circumferential direction and the center portion relatively thicker, each detected portion 1b is made relatively thicker toward both ends in the entering and exiting direction.

A pair of detected parts 1b of the movable metal body 1
In each case, the central part in the entrance / exit direction is relatively narrow over a predetermined length, and both ends are gradually thickened from the narrow central part.

In such a non-contact position sensor, the movable metal body 1 is relatively thick near both ends in the direction of entering and exiting the sensor coil 5, so that it can be compared with a case where the thickness is uniform. Thus, the magnetic flux passing through the inside of the movable metal body 1 can be increased. Therefore, even if both ends of the movable metal body 1 enter near both ends in the axial direction where the magnetic field is smaller than the central part in the axial direction, the output accuracy of the output signal corresponding to the position of the movable metal body 1 can be increased. .

In the present embodiment, the detected portion 1b of the movable metal body 1 has a relatively narrow central portion in the direction of entry and exit over a predetermined length, and gradually extends from the narrow central portion to both ends. As shown in the schematic diagram of FIG. 21, the same effect can be obtained even if a part of the center in the in-out direction is relatively narrowed and both ends are gradually thickened from the narrow center as shown in the schematic diagram of FIG.

In each of the first to fourth embodiments, the detected portion 1b of the movable metal body 1 and the sensor coil 5 are formed in an arc shape, but may be formed in a linear shape. The same effect can be obtained.

[0029]

According to the first aspect of the present invention, since the number of turns per unit length along the axial direction of the sensor coil is relatively increased near both ends in the axial direction, the non-contact position sensor according to the first aspect has the following advantages. The magnetic field near both ends in the axial direction of the sensor coil increases as compared with the case where the number of turns in the unit length is made uniform, and the magnetic field near both ends in the axial direction is substantially equal to the magnetic field in the central part in the axial direction. It can be about the same. Therefore, even if both ends of the metal shaft enter near both ends in the axial direction of the sensor coil, the output accuracy of the output signal corresponding to the position of the movable metal body can be increased.

In the non-contact position sensor according to the second aspect, in the sensor coil, since the magnetic field gradually decreases toward both ends, the number of turns in a unit length along the axial direction gradually increases toward both ends. By increasing the number, the output accuracy of the output signal corresponding to the position of the movable metal body can be further increased.

According to a third aspect of the present invention, in addition to the effect of the non-contact type position sensor according to the first aspect, the number of windings per unit length along the axial direction is increased along the axial direction. It can be managed for each turn space, and variations in the number of turns can be reduced.

In the non-contact type position sensor according to the fourth aspect, the movable metal body is relatively thick near both ends in the direction of entering and exiting the sensor coil. Thus, the magnetic flux passing through the inside of the movable metal body 1 can be increased. Even if both ends of the movable metal member enter near both ends in the axial direction where the magnetic field is smaller than the central portion in the axial direction, the output accuracy of the output signal corresponding to the position of the movable metal member can be increased.

In the non-contact position sensor according to the fifth aspect, since the magnetic field gradually decreases toward the both ends in the sensor coil, the both ends of the movable metal body in the direction of entering and exiting the sensor coil gradually increase. By increasing the thickness, the output accuracy of the output signal corresponding to the position of the movable metal body can be further increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a sensor coil according to a first embodiment of the present invention.

FIG. 2 is a plan view of the above device with a cover removed.

FIG. 3 is a front sectional view of the same.

FIG. 4 is a plan view showing the shape of one coil bobbin of the above.

FIG. 5 is a sectional view taken along line X1-X2 of FIG. 4;

FIG. 6 is a sectional view taken along line X3-X4 of FIG. 4;

FIG. 7 is a front view of one coil bobbin of the above.

FIG. 8 is a rear view showing the shape of one coil bobbin of the above.

FIG. 9 is a rear view showing the shape of the other coil bobbin of the above.

FIG. 10 is a plan view showing the shape of the metal shaft of the above.

11 is a sectional view taken along line X5-X6 of FIG.

FIG. 12 is a front view showing the shape of the metal shaft according to the third embodiment.

FIG. 13 is a front view of the same molding block.

FIG. 14 is a top view of the above.

FIG. 15 is a bottom view of the same.

FIG. 16 is a front sectional view of the above.

FIG. 17 is a schematic view of a sensor coil according to a second embodiment of the present invention.

FIG. 18 is a schematic view of a sensor coil according to a third embodiment of the present invention.

FIG. 19 is a plan view illustrating a shape of a metal shaft according to a fourth embodiment of the present invention.

FIG. 20 is a front view showing the shape of the metal shaft according to the third embodiment.

FIG. 21 is a schematic view of a metal shaft gradually narrowed to the center.

FIG. 22 is a schematic configuration diagram of a conventional example.

FIG. 23 is a schematic diagram showing a state in which the metal shaft enters the sensor coil.

FIG. 24 is an explanatory diagram showing output signals of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Movable metal body 1b Detected part 3e Partition part 5 Sensor coil

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shoji Miyazaki 1048 Odakadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. VV02

Claims (5)

[Claims] 1. A movable metal body having a sensor coil, and a detected part whose occupancy in a magnetic path changes by entering and exiting a center through hole of the sensor coil along an axial direction of the sensor coil;
Detects the position of the movable metal body along the axial direction by driving and exciting the sensor coil, generating a high-frequency modulated magnetic field, and detecting the magnetic change of the sensor coil that occurs as the detected part moves in and out. In the non-contact position sensor, the number of turns of the sensor coil per unit length along the axial direction is relatively increased near both ends in the axial direction. 2. The non-contact position sensor according to claim 1, wherein the number of turns of the sensor coil per unit length along the axial direction gradually increases toward the both ends. 3. A partition portion for partitioning a winding space along the axial direction is provided, and the sensor coil relatively controls the number of turns in a unit length along the axial direction in the winding space near both ends in the axial direction. The non-contact type position sensor according to claim 1, wherein the number is increased. 4. A sensor coil comprising: a sensor coil; and a movable metal body having a detected part whose occupancy with respect to a magnetic path changes in and out of a center through hole of the sensor coil along the axial direction, and drives the sensor coil. In a non-contact type position sensor that detects the position of a movable metal body along the axial direction by exciting and generating a high-frequency modulated magnetic field and detecting the magnetic change of the sensor coil that occurs according to the entrance and exit of the detected part A non-contact type position sensor, wherein the detected part has relatively thick portions near both ends in the direction of entering and exiting the sensor coil. 5. The non-contact position sensor according to claim 4, wherein the detected portion is gradually thicker toward the both ends.