JPH11211410A - Non-contact position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact position sensor for detecting a rotating displacement position or linear displacement position which is hardly affected by the physical movement of a magnetic generating body and a magnetic sensitive element, suitable for the use in an automobile, and highly precise, and has a simplified magnetic circuitry. SOLUTION: A magnetic generator 3 arranged on a rotating shaft 8 rotated in reaction to an external rotating operation and magnetized vertically to the rotating shaft 8 is housed within a first yoke 1 and a second yoke 2 under the presence of air gaps of the axial direction of the rotating shaft 8 and of the orthogonal direction to the rotating shaft 8, and a magnetic sensitive element 4 sensitive to the magnetic flux change within a cavity 5 between the first yoke 1 and the second yoke 2 formed in parallel to a first plane passing the rotating shaft 8 is arranged within this cavity 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-contact type position sensor for detecting a rotational displacement position and a linear displacement position.

[0002]

2. Description of the Related Art Conventionally, for example, a rotary position sensor used as a throttle opening sensor of a vehicle-mounted internal combustion engine, a linear position sensor used as a valve stroke sensor of the engine, and the like, determine a rotation angle and a linear movement amount of an object to be detected. Sliding resistors were often used as sensors for detection.

[0003] However, this sliding resistor has many problems in terms of accuracy as a sensor, such as fluctuation of output characteristics and generation of noise due to friction and fouling of a sliding portion. Was.

Therefore, at present, for example, Japanese Patent Publication No. 63-66
As in the position sensor described in Japanese Patent Application Publication No. 404, the so-called non-contact detection of the rotation angle and the amount of linear movement of the detection target using two magnetic resistors (elements) electrically connected in series in a non-contact manner. Contact type position sensors are being used.

Incidentally, in such a non-contact type position sensor,
When the magnet disposed at a position facing the surface on which the magnetoresistive element is disposed is displaced with the rotation or movement of the object to be detected, a change in the resistance value of the magnetoresistive element corresponding to a change in the intensity of the magnetic field. The position of the detection object is detected. For this reason,
Since the sensor element itself has no sliding portion, there is no concern that the output characteristics fluctuate or noise is generated due to friction or contamination.

[0006] In addition, a non-contact type position sensor described in Japanese Patent Publication No. 9210722 is known. The sensor comprises a magnet surrounding a rotating shaft and a stator located on the opposite side of the magnet. The stator is fixed to the casing by a fixture, and the hall sonde and the exciting winding are arranged in the recess of the stator so as to face each other.

[0007]

However, in the above-mentioned first prior art magnetic circuit, the sensor receives both radial and axial forces, and these forces are applied to the matching state of the object to be detected with respect to the magnetic resistor. To change. The device is provided with at least one bearing, which has a certain amount of play or movement. As a result of this play, the detected object moves with respect to the magnetoresistive element.

[0008] Unfortunately, the first prior art magnetic circuit is very susceptible to physical movements of the object to be detected and the magnetic resistor. As described above, this movement may occur in an axial direction parallel to the axis of rotation, or in a radial direction perpendicular to the axis of rotation, or a combination of both.

In the second prior art sensor, since the magnet used is a magnet which is cross-magnetized radially, its material is limited, and the temperature characteristics of the magnet pose a problem when used in an automobile. Therefore, improvements are needed for use in automobiles.

The present invention is less affected by the physical movement of the object to be detected and the magnetoresistive element and is suitable for use in an automobile.
An object of the present invention is to provide a highly accurate non-contact type position sensor having a simple magnetic circuit configuration.

[0011]

According to the present invention, there is provided a non-contact type position sensor having a first yoke piece and a second yoke piece.
A yoke, a second yoke having a third yoke piece facing the first yoke piece and a fourth yoke piece facing the second yoke piece, and rotating in response to a rotation operation from outside; A magnetic generator arranged on a rotation axis and magnetized in a direction perpendicular to the rotation axis, and disposed in a gap between the first and second yokes formed parallel to a first plane passing through the rotation axis; And a magnetic sensing element responsive to a change in magnetic flux in the air gap due to rotation of the magnetic generator.
The yoke and the second yoke have a key-shaped cross-section perpendicular to the first plane passing through the rotation axis and on a second plane passing through the rotation axis. The inner circumferences of the first and second yokes are rotatable in the presence of an air gap in an axial direction and a direction orthogonal to the rotation axis. With this configuration, it is possible to obtain a non-contact type position sensor that is hardly affected by physical movement between the magnetic generator and the magnetic sensing element, is suitable for use in an automobile, has high accuracy, and has a simple magnetic circuit configuration.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to a first aspect of the present invention, there is provided a first yoke having a first yoke piece and a second yoke piece, and a third yoke opposed to the first yoke piece. A second yoke having a piece and a fourth yoke piece facing the second yoke piece, and a second yoke arranged on a rotating shaft that rotates in response to a rotation operation from the outside, and magnetized in a direction perpendicular to the rotating axis. Disposed in a gap between the first and second yokes formed in parallel with a first plane passing through the rotation axis, and a magnetic flux in the gap caused by rotation of the magnetic generator. A magnetic sensing element responsive to a change, wherein the first yoke and the second yoke are keyed on a second plane perpendicular to the first plane passing through the rotation axis and on a second plane passing through the rotation axis. It has a cross-sectional shape, and the magnetic generator is in the axial direction of the rotating shaft and the rotating shaft. Since the inner circumferences of the first and second yokes can be rotated in the presence of the air gap in the intersecting direction, the first and second yokes are hardly affected by the displacement of the magnetic generator in the axial direction and the radial direction of the shaft, It is possible to realize a sensor that is suitable for use in an automobile, has high performance, and has a simple magnetic circuit configuration.

According to a second aspect of the present invention, in the first aspect, since the first and second yokes are each formed of a bottomed semi-cylindrical yoke piece, the axial direction and the axial direction are different. And a high-performance sensor which is hardly affected by the displacement of the magnetic generator in the radial direction.

According to a third aspect of the present invention, in the first aspect of the present invention, a spacer made of a non-magnetic material is disposed in a gap between the first and second yokes and mechanically integrated. Therefore, the gap between the yokes is determined by the spacer, and as a result, the yoke can be easily positioned,
Characteristics can be stabilized.

According to a fourth aspect of the present invention, in the first or the third aspect of the present invention, a filler is inserted into a space between the first and second yokes, and the magnetically responsive element is therein. Is held, the position of the magnetically sensitive element can be completely fixed, and a sensor that is robust against mechanical vibration can be realized.

According to a fifth aspect of the present invention, in the first aspect of the present invention, at least two or more of the magnetically sensitive elements are disposed in the gap, so that two or more signals are output from the sensor. When output is required, a desired output can be obtained.

According to a sixth aspect of the present invention, in the first aspect of the invention, the magnetic flux is concentrated only in the area where the magnetically sensitive element is disposed in the gap between the first and second yokes. As described above, since the end gap distance of the opposing surface of the yoke is adjusted, the amount of magnetic flux applied to the magnetically sensitive element can be adjusted, and thus the sensitivity of the sensor can be adjusted.

According to a seventh aspect of the present invention, in the first aspect of the invention, since the magnetic generator has a positioning hole coaxial with the rotation axis, the magnetic generator can be easily mounted on the rotation axis. They can be arranged, and high performance of the sensor can be realized.

According to an eighth aspect of the present invention, in the invention according to any one of the first to seventh aspects, since the magnetic generator is composed of a cubic magnet, machining of the magnet is easy. Thus, a compact magnetic circuit configuration can be realized.

According to a ninth aspect of the present invention, in the first aspect of the present invention, the magnetic generator is formed of a ring-shaped magnet.
When the second yoke is a yoke piece having a semi-cylindrical shape with a bottom, the linearity of the sensor output becomes better, and a high-performance sensor can be realized.

According to a tenth aspect of the present invention, in the first aspect of the present invention, since the magnetic generator is formed of a disk-shaped magnet,
When the second yoke is a semi-cylindrical yoke piece, the linearity of the sensor output becomes better, and a high-performance sensor can be realized.

According to an eleventh aspect of the present invention, in the invention according to any one of the first to seventh aspects, the magnetic generator comprises a magnet and a back yoke formed in the magnetization direction of the magnet. Therefore, the size of the magnet can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1A is a cross-sectional view for explaining the principle of a first embodiment of the non-contact type position sensor of the present invention, and FIG. 1B is a top view thereof. . In FIG. 1, reference numeral 1 denotes a first yoke having a first yoke piece 1a and a second yoke piece 1b, and 2 denotes a third yoke piece 2a and the second yoke piece facing the first yoke piece 1a. A second yoke 3 having a fourth yoke piece 2b opposed to 1b is provided with a magnetic generator disposed on a rotating shaft 8 which rotates in response to a rotation operation from the outside, and 4 is associated with the rotation of the magnetic generator 3. A magnetic sensing element that senses a change in magnetic flux in the gap 5, 5 is a gap between the first yoke 1 and the second yoke 2, 6 is a mounting unit for connecting the shaft member and the magnetic generator 3, 7 is A shaft member connected to the mounting unit 6, 8 is a rotation axis of the magnetic generator 3, 10 is an air gap between the first yoke piece 1a and the third yoke piece 2a, and 20 is the first yoke piece 1a or the first yoke piece 1a. 3, the air gap between the yoke piece 2a and the magnetic generator 3; The second yoke pieces 1b or fourth yoke piece 2
This is the air gap between b and the magnetic generator 3. In the present embodiment, the first yoke 1 and the second yoke 2 are made of a soft magnetic material, and are arranged to face each other under an air gap 10. The magnetic generator 3 has a rectangular parallelepiped SmC having a square cross section perpendicular to the rotation axis 8.
The permanent magnet o is uniaxially oriented in a direction perpendicular to the rotation axis 8, and the magnetization is oriented in this direction. The magnetically sensitive element 4 is formed of a Hall element, and is fixed in the gap 5 by a filler or the like on the rotating shaft 8 so that the magnetic flux 11 passing through the sensing surface 12 and the gap 5 is vertical as shown in FIG. Is done.
The mounting unit 6 and the shaft member 7 are made of a non-magnetic material such as stainless steel so as not to affect the magnetic circuit.

Next, the principle of operation will be described with reference to FIG. FIG. 3A shows the relationship between the rotation angle θ of the magnetic generator 3 and the output voltage. FIGS. 3B to 3E are schematic diagrams showing the state of rotation of the magnetic generator 3. First, FIG.
When the sensing surface 12 of the magnetic sensing element 4 and the magnetization direction 13 are parallel as in (c), the magnetic flux 11 applied to the sensing surface 12 becomes zero. This state is defined as θ = 0. Thus, when the magnetic generator 3 rotates and θ increases or decreases, the amount of magnetic flux flowing through the first yoke 1 and the second yoke 2 changes. Along with this, the magnetic flux 11 applied to the sensing surface 12 also changes,
The output also fluctuates. Here, the linear region of the output is secured to some extent in the range of about ± 45 degrees in FIGS. 3D to 3E, and in other regions, the output approaches a saturated state.

In this magnetic circuit configuration, the magnetic flux distribution in the air gap 5 becomes uniform at a certain rotation angle of the magnetic generator 3. Therefore, the magnetic sensing element 4 is hardly affected by the displacement of the mounting position. Further, since the magnetically sensitive element 4 is disposed in the closed magnetic circuit, it is possible to prevent the magnetic generator 3 from being displaced in the axial direction and the radial direction of the axis, that is, against the fluctuation of the air gap 20 or the air gap 30. Very unlikely to be affected.

Further, as shown in FIG.
In the case where the gap distance between the end portions of the opposing surfaces 16 of the first yoke piece 1a and the third yoke piece 2a is adjusted so that the magnetic flux is concentrated only in the arrangement region, the displacement of the magnetic generator 3 can be reduced. In addition to the effect of being hardly affected, the total amount of magnetic flux in the closed magnetic circuit can be adjusted. That is, the sensitivity of the sensor can be adjusted by adjusting the end gap distance of the facing surface 16.

As described above, in the configuration of the present embodiment, the mounting position of the magnetic sensing element 4 and the displacement of the magnetic generator 3 in the axial direction and the radial direction of the shaft are less likely to be affected, and the performance is high. A simple sensor having a magnetic circuit configuration can be realized.

In this embodiment, the magnetic sensitive element 4
Although only an example using a Hall element has been described above, the present invention is not necessarily limited to this. Further, in the present embodiment, a case has been described in which a rectangular parallelepiped SmCo permanent magnet having a square cross section perpendicular to the rotation axis 8 is used as the magnetic generator 3, but this shape is a ring-shaped magnet or a disk-shaped magnet. Alternatively, as shown in FIGS. 5 (a) and 5 (b), a magnet 14 and a back yoke 15 formed in its magnetization direction 13 may be used.

(Embodiment 2) FIG. 6A is a sectional view for explaining the principle of a second embodiment of the non-contact type position sensor of the present invention, and FIG. FIG.
6, the same components as those in FIG. 1 are denoted by the same reference numerals, detailed description thereof will be omitted, and only different components will be described. In FIG. 6A, the first yoke 1 and the second yoke 1
The yoke 2 is composed of a bottomed semi-cylindrical yoke piece.
Under the air gap 10, they are arranged to face each other with the air gap 5 therebetween. The magnetic generator 3 is made up of a disk-shaped permanent magnet, and is connected to a shaft member 7 also made of a non-magnetic material via a mounting unit 6 made of a non-magnetic material. Further, the magnetic generator 3 is disposed under the air gap 20 and the air gap 30.

The principle of operation of the present embodiment is basically the same as that described in the first embodiment, and a detailed description thereof will be omitted.

The present embodiment differs from the first embodiment in that a disk-shaped permanent magnet 3 and bottomed semi-cylindrical yokes 1 and 2 are used. In this configuration, as described in the first embodiment, the influence of the displacement of the magnetic generator 3 in the axial direction and the radial direction of the shaft, that is, the fluctuation of the air gap 20 or the air gap 30 is extremely affected. Hard to receive. Further, since the air gap 30 hardly changes with the rotation of the magnetic generator 3, the linearity in the range of about ± 45 degrees of the output voltage of the sensor is better than that of the first embodiment. Become.

As shown in FIG. 7, when a spacer 17 made of a non-magnetic material is disposed in the space 5 between the first yoke 1 and the second yoke 2 having a bottomed semicylindrical shape, the air gap 1
0 is determined by the spacer 17, and as a result, the positioning of the first yoke 1 and the second yoke 2 having the bottomed semi-cylindrical shape is facilitated, and the characteristics can be stabilized.

As shown in FIG. 8, when the magnetic generator 3 is made of a semi-ring type permanent magnet and is fixed on the mounting unit 6, the above-described effects can be obtained. Is possible. In this case, a permanent magnet that is radially magnetized is used.

As described above, in the configuration of the present embodiment, the linearity in the range of about ± 45 degrees of the output voltage of the sensor is better than that of the first embodiment, and the characteristics are stable. Can be

In the description of the present embodiment, only an example of a one-band type using one magnetic sensitive element 4 has been described. However, by preparing a plurality of these magnetic sensitive elements 4, one It is also possible to detect an abnormal state and perform a self-diagnosis by using the output of the above or an output combining them, and to improve various characteristics by using the combined output of both.

[0036]

As described above, according to the present invention, it is hardly affected by the physical movement of the magnetic generator and the magnetic sensing element, is suitable for use in automobiles, has high accuracy, and has a simple magnetic circuit configuration. A non-contact type position sensor can be obtained.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating a first embodiment of a non-contact type position sensor according to the present invention. FIG. 1B is a top view of the sensor.

FIG. 2 is a schematic diagram showing a relationship between a magnetic sensing element and a magnetic flux of the sensor.

3A is an output characteristic diagram of the same sensor. FIGS. 3B, 3C, 3D, and 3E are schematic diagrams showing the operation principle of the same sensor.

FIG. 4 is a schematic view showing another yoke piece of the sensor.

FIGS. 5A and 5B are schematic diagrams showing another magnetic generator of the same sensor.

FIG. 6A is a sectional view showing another embodiment of the non-contact type position sensor of the present invention. FIG. 6B is a top view of the sensor.

FIG. 7 is a schematic view showing another embodiment of the sensor.

FIG. 8 is a schematic view showing another embodiment of the sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st yoke 1a 1st yoke piece 1b 2nd yoke piece 2 2nd yoke 2a 3rd yoke piece 2b 4th yoke piece 3 Magnetic generator 4 Magnetic sensing element 5 Air gap 6 Mounting unit 7 Shaft material 8 Rotation Axis 10 Air gap 11 Magnetic flux 12 Sensing surface 13 Magnetization direction 14 Magnet 15 Back yoke 16 Opposing surface 17 Spacer 20 Air gap 30 Air gap

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01D 5/14 G01D 5/14 H

Claims (11)

[Claims] A first yoke having a first yoke piece and a second yoke piece; a third yoke piece facing the first yoke piece; and a fourth yoke piece facing the second yoke piece. A second yoke having a yoke piece, a magnetic generator arranged on a rotating shaft that rotates in response to a rotating operation from the outside, magnetized in a direction perpendicular to the rotating shaft, and a first plane passing through the rotating shaft A magnetic sensing element disposed in an air gap between the first and second yokes formed in parallel to each other and responsive to a change in magnetic flux in the air gap due to rotation of the magnetic generator. The first yoke and the second yoke have a key-shaped cross section perpendicular to the first plane passing through the rotation axis and on a second plane passing through the rotation axis. In the presence of an air gap in the axial direction of the shaft and in the direction perpendicular to the rotation axis, A non-contact type position sensor wherein the inner circumferences of the first and second yokes are rotatable. 2. The non-contact type position sensor according to claim 1, wherein said first and second yokes are each formed of a bottomed semi-cylindrical yoke piece. 3. The non-contact position sensor according to claim 1, wherein a spacer made of a non-magnetic material is disposed in a gap between the first and second yokes and is mechanically integrated. 4. The non-contact type position according to claim 1, wherein a filler is inserted into a gap between the first and second yokes, and the magnetically sensitive element is held therein. Sensor. 5. The non-contact position sensor according to claim 1, wherein at least two or more of said magnetically sensitive elements are arranged in said gap. 6. An end gap distance on an opposing surface of the yoke such that magnetic flux is concentrated only in a region where a magnetically sensitive element is disposed in a gap between the first and second yokes. The non-contact type position sensor according to claim 1, wherein: 7. The non-contact type position sensor according to claim 1, wherein the magnetic generator has a positioning hole coaxial with the rotation axis. 8. The non-contact type position sensor according to claim 1, wherein the magnetic generator comprises a cubic magnet. 9. The non-contact type position sensor according to claim 1, wherein the magnetic generator comprises a ring-shaped magnet. 10. The non-contact type position sensor according to claim 1, wherein the magnetic generator comprises a disk-shaped magnet. 11. The non-contact type position sensor according to claim 1, wherein the magnetic generator comprises a magnet and a back yoke formed in a direction of magnetization of the magnet.