JPH0564707U - Rotational position sensor - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to obtain a rotational position sensor that can improve reliability. [Structure] The core 56 has a core intermediate portion 88 having a laminated structure of thin plates and both end portions 90 of the core which are closely attached to both end surfaces thereof.
It consists of and. Then, the two are welded and integrated at the welding portions 92 and 94. For this reason, it is possible to prevent the surface of the core from being deformed or peeled off, and it is possible to improve the reliability.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotational position sensor, and more particularly to an inductance type rotational position sensor that detects a rotational position of a rotated position detection member based on a change in inductance of a coil.

[0002]

[Prior Art]

 Conventionally, a rotational position sensor has been used to detect the rotational position of a rotational position detecting member, for example, a rotating shaft of a motor or the like. In this type of rotational position sensor, it corresponds to the ring-shaped core, the detection side coil wound around a part of the outer circumference of the core, the reference side coil arranged adjacent to the detection side coil, and the reference side coil. It is equipped with a fixed short ring that is fixed in place, and a movable short ring that is connected to the tip of the rotating shaft and rotates relative to the detection side coil in the direction of moving toward and away from the detecting coil. The rotational position of the rotating shaft is detected by comparing the inductance of the detection side coil, which changes due to the rotating movable short ring, with the inductance of the reference side coil for temperature compensation.

By the way, although such a rotational position sensor is required to have high reliability, the rotational position sensor described above is configured to apply a high frequency to the reference side coil and the detection side coil to detect a change in the magnetic field. Therefore, it can be said that the one with small loss in the core is preferable. Therefore, conventionally, as shown in FIGS. 7 (A) and 7 (B), a core 100 serving as an iron core is formed by stacking thin plate materials such as a silicon steel plate and permalloy (as an example, See Japanese Patent Application No. 3-37344).

[0004]

[Problems to be solved by the device]

 However, when the core 100 is formed by stacking thin plate materials, the thin plate material on the surface of the core 100 may be deformed and separated due to vibration or the like. In this case, there is a problem in that the rotary short-circuit sensor comes into contact with the rotating movable short ring to reduce the reliability of the rotary position sensor.

On the other hand, the detection accuracy of the rotational position sensor largely depends on whether or not fine adjustment can be performed when the assembly is performed. That is, if the relative position between the rotational position sensor and the parts to be assembled such as the motor deviates from the predetermined assembly position, the initial position of the movable short ring deviates, and the output voltage of the rotational position sensor for the same rotational position changes. The initial value (zero point on the graph showing the sensor characteristics) will be shifted. Also, in the rotational position sensor itself, if the position of the fixed short ring on the core with respect to the reference side coil deviates from the predetermined fixed position, the magnetic path with respect to the reference side coil becomes longer or shorter, and the amount of change in the rotational position is The ratio of the amount of change in the output voltage (the slope of the graph showing the sensor characteristics) changes accordingly. That is, there is a problem in that the characteristics of the rotational position sensor vary, and the detection accuracy of the rotational position sensor decreases.

In consideration of the above facts, the present invention has an object to obtain a rotational position sensor which can improve reliability.

[0007]

[Means for Solving the Problems]

 The present invention according to claim 1 is directed to a rotated position detecting member that rotates about an axis, a reference side portion that is disposed apart from the rotated position detecting member in the circumferential direction, and forms a reference magnetic path, and a detection unit. A ring-shaped core having a detection-side portion forming a side magnetic path, a reference-side coil wound around the reference-side portion, a detection-side coil wound around the detection-side portion, and the rotated position A rotating member that is coaxially connected to the detection member and is arranged so as to be relatively rotatable in the detection side portion in a direction toward and away from the detection side coil, and changes the inductance of the detection side coil by rotating. And a fixing member which is arranged at a position separated from the reference side coil by a predetermined distance in the reference side portion, and which compensates for a change in inductance of the detection side coil due to a change in environmental temperature, An inductance type rotational position sensor for detecting the rotational position of the rotational position detecting member while comparing the inductances of the reference side coil and the detection side coil, wherein the core is formed by laminating a plurality of thin plates. The core intermediate portion formed by the above, and both end portions of the core that are closely arranged on both end faces in the thickness direction of the core intermediate portion and are thicker than the thin plate described above. I am trying.

According to a second aspect of the present invention, in the rotational position sensor according to the first aspect, the core intermediate portion and the both side portions of the core are mutually fixed by at least two portions which are opposed to each other in the radial direction of the core by a fixing means. It is characterized by being fixed to.

According to a third aspect of the present invention, in the rotary position sensor according to the first aspect, the core is formed by sintering ferrite.

According to a fourth aspect of the present invention, a rotated position detecting member that rotates around an axis and a reference side portion that is arranged in the circumferential direction of the rotated position detecting member and is spaced apart from each other to form a reference magnetic path. A ring-shaped core having a detection side portion forming a magnetic path and a detection side magnetic path, a reference side coil wound around the reference side portion, and a detection side coil wound around the detection side portion, It is coaxially connected to the rotated position detection member, and is arranged so as to be relatively rotatable in the detection side portion toward and away from the detection side coil, and the inductance of the detection side coil is changed by rotating. The rotating member and the reference side coil are arranged at a predetermined distance from the reference side coil for compensating the change in the inductance of the detection side coil due to the change in the environmental temperature. A fixed member, which detects the rotational position of the rotated position detection member while comparing the inductances of the reference side coil and the detection side coil, wherein the fixed side is the reference side of the fixed member. It is characterized in that fixed position adjusting means for finely adjusting the fixed position relative to the coil is provided.

According to a fifth aspect of the present invention, a rotated position detecting member that rotates around an axis and a reference side portion that is arranged in the circumferential direction of the rotated position detecting member and is spaced apart from each other to form a reference magnetic path. A ring-shaped core having a detection side portion forming a magnetic path and a detection side magnetic path, a reference side coil wound around the reference side portion, and a detection side coil wound around the detection side portion, It is coaxially connected to the rotated position detection member, and is arranged so as to be relatively rotatable in the detection side portion toward and away from the detection side coil, and the inductance of the detection side coil is changed by rotating. The rotating member and the reference side coil are arranged at a predetermined distance from the reference side coil for compensating the change in the inductance of the detection side coil due to the change in the environmental temperature. A fixed member, which is an inductance type rotational position sensor for detecting the rotational position of the rotational position detecting member while comparing the inductances of the reference side coil and the detection side coil, wherein the rotational position of the core is It is characterized in that an assembly position adjusting means for finely adjusting the assembly position in the circumferential direction relative to the detection member is provided.

[0012]

[Action]

 According to the rotational position sensor of the present invention as set forth in claim 1, when the rotated position detecting member rotates by a predetermined angle, the rotating member coaxially connected to the rotated position detecting member is integrated with the rotated position detecting member. In addition, in the detection side portion of the core, the core relatively rotates in the direction toward and away from the detection side coil. Therefore, the inductance of the detection side coil changes.

Further, the fixing member is arranged at the reference side portion of the core at a position separated from the reference side coil by a predetermined distance. Inductance changes equally occur in both of the reference side coils that have been set. Therefore, by comparing the inductances of both coils, changes in the inductance of the detection coil due to changes in the ambient temperature are compensated for, and only changes in the inductance of the detection coil due to rotation of the rotated position detection member are detected. To be done. As a result, the rotational position of the rotated position detecting member can be detected.

Here, according to the present invention, the core has a core intermediate portion formed by laminating a plurality of thin plates, and the thin plates are closely arranged on both end faces in the thickness direction of the core intermediate portion. Since both ends of the core are made thicker than the core, deformation and peeling that would occur in the case of a core formed only by stacking thin plates are prevented by the ends of the core. Since the middle part of the core is formed by laminating thin plates, the loss due to the eddy current generated in the rotating member is also reduced.

Therefore, in the rotational position sensor of the present invention, since the core is configured by the core intermediate portion and the core both ends, the core is prevented from being deformed or peeled, and reliability is improved. ..

According to the present invention as set forth in claim 2, in the present invention as set forth in claim 1, the core intermediate portion and the core both ends are fixed to each other at least at two positions facing each other in the radial direction of the core by the fixing means. Therefore, the above-mentioned effects can be obtained more reliably.

According to the third aspect of the present invention, in the first aspect of the present invention, since the core is formed by sintering the ferrite, the core can be formed as an integral part. For this reason, not only the step of laminating a plurality of thin plates is unnecessary, but also defects such as deformation and peeling of the thin plates are eliminated. Further, since the ferrite itself has a property that the eddy current loss in the magnetic field due to the high frequency is small, the reliability of the rotational position sensor can be improved.

According to the fourth aspect of the present invention, the length of the reference side magnetic path in the core is finely adjusted by finely adjusting the fixed position of the fixing member relative to the reference side coil by the fixed position adjusting means. can do. Therefore, the ratio of the amount of change in the output voltage to the amount of change in the rotational position in the characteristics of the rotational position sensor can be finely adjusted. Therefore, the detection accuracy of the rotational position sensor can be improved.

According to the fifth aspect of the present invention, the assembling position adjusting means finely adjusts the relative assembling position in the circumferential direction with respect to the rotated position detecting member of the core. The initial position of is also finely adjusted. Therefore, it is possible to adjust the initial value of the output voltage for the same rotational position in the characteristic of the rotational position sensor. Therefore, the detection accuracy of the rotational position sensor can be improved.

[0020]

【Example】

 Hereinafter, the rotational position sensor 10 according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 3 shows a sectional view of the motor 12 to which the rotational position sensor 10 is attached.

The motor 12 includes a housing 24 including a lower housing 14, an intermediate lower housing 16, an intermediate upper housing 18, an upper housing 20 and a side housing 22. The housing 24 includes a rotational position sensor described later. It houses 10 functional parts. An O-ring 26 is fitted and sealed on the abutting surface of each housing 14 to 22, and the housings 14 to 22 are joined to each other at appropriate places by a joining means such as a bolt 28 or welding. ..

The intermediate lower housing 16 has a cylindrical shape, and the motor core 30 is arranged on the inner peripheral side thereof. A rotor 32 is rotatably arranged inside the motor core 30. A coil 36, which is energized via a harness 34 housed in the side housing 22, is wound around a part of the motor core 30 in the circumferential direction, and the motor core 30 is excited by energizing the coil 36. The rotor 32 is adapted to rotate. A return spring (not shown) is locked to the rotor 32, and the rotor 32 rotates until the biasing force of the return spring and the magnetic force generated in the motor core 30 are balanced. A rotating shaft 38, which serves as a rotated position detecting member whose axial lower end portion and intermediate portion are axially supported by ball bearings, is penetratingly arranged in the shaft core portion of the rotor 32 so as to rotate integrally with the rotor 32. It has become.

A rotational position sensor 10 is arranged between the intermediate upper housing 18 and the upper housing 20. As shown in FIGS. 1 and 2, the rotational position sensor 10 includes a substantially elliptical mounting plate 46. The mounting plate 46 has screw holes 48 (see FIG. 1) formed at its four corners as elongated holes, and is attached to the intermediate upper housing 18 with screws 50 (see FIG. 2). In addition, the mounting plate 46 is provided with a claw 52 for positioning with respect to the intermediate upper housing 18, and a U-shaped notch 54 as an assembling position adjusting means for fine adjustment of a zero point described later. There is. Further, the mounting plate 46 is provided with three cylindrical or semi-cylindrical support portions (not shown) standing upright. A core 56 is placed on these supporting portions, and in this state, the core 56 is attached to the mounting plate 46 with screws 58.

As shown in FIGS. 1, 2 and 4, the core 56 is composed of a detection section 60 as a detection side section and a compensation section 62 as a reference side section. As shown in detail in FIG. 4A in which the core 56 is shown in a plan view, the detection portions 60 of the core 56 are located inside and outside, respectively, and are formed in concentric ring shapes. Similarly, the compensating portion 62 of the core 56 is also formed in a concentric ring shape located inside and outside, respectively. The base ends of the detector 60 and the compensator 62 are integrally connected to form a mounting base 64. Further, mounting holes 66 through which the above-mentioned screws 58 penetrate are formed in the respective tip portions of the detection portion 60 and the compensation portion 62 of the core 56, and similarly, the mounting holes 66 are also formed in the mounting base portion 64. ing.

The ring center O ₁ of the detecting portion 60 of the core 56 and the ring center O ₂ of the compensating portion 62 are formed so as to be separated from each other by a predetermined distance L. Therefore, the core 56 is formed in an elliptical shape as a whole. Has been done. This improves the assemblability of the core 56 and expands the rotatable range, that is, the detection range of the movable short ring 76, which will be described later. The core 56 is arranged so that the ring center O ₁ of the detection unit 60 is aligned with the axis of the rotary shaft 38 of the motor 12. Therefore, the rotation center of the movable short ring 76, which will be described later, also coincides with the ring center O ₁ of the detection unit 60.

As shown in FIGS. 1 and 2, a detection side coil 68 coated with a resin is wound around the base end portion (side of the attachment base portion 64) of the detection portion 60 of the core 56. There is. A compensation side coil 70 as a reference side coil, which is also coated with resin, is wound around the base end portion of the compensation portion 62. The detection side coil 68 and the compensation side coil 70 are energized via lead wires 72 and 74 (see FIG. 1), respectively. An AC magnetic field is generated in the detection unit 60 and the compensation unit 62 of the core 56 by the application of the AC current.

A movable short ring 76 as a rotating member is arranged on the outer periphery of the detection unit 60 of the core 56. A pair of rectangular through holes 78 corresponding to the detecting portion 60 of the core 56 are formed in the movable short ring 76, and the detecting portion 60 is relatively rotatably inserted into these through holes 78. Therefore, an eddy current is generated in the movable short ring 76 due to the AC magnetic field generated in the detection unit 60. One end of the movable short ring 76 is fixed to the rotating shaft 38 of the motor 12 by a nut 80. Therefore, the movable short ring 76 is always integrated with the rotating shaft 38 of the motor 12 and is relatively rotated along the detecting portion 60 of the core 56. As a result, when the position of the movable short ring 76 changes, the position where the magnetic flux generated in the detection side coil 68 is cut changes, so that the magnetic path becomes longer or shorter, and the inductance of the detection side coil 68 changes.

On the other hand, a fixed short ring 82 as a fixing member is arranged on the outer periphery of the compensation portion 62 of the core 56. The fixed short ring 82 is fixed to a predetermined position of the compensating portion 62 (for example, a position corresponding to half the moving range of the movable short ring 76) using the above-mentioned mounting hole 66 and the screw 58. That is, the fixed short ring 82 is a portion where a pair of through holes 84 through which the compensating portion 62 of the core 56 is formed and a portion which is bent from the lower end portion thereof and extends along the circumferential direction of the core 56 ( (Not shown), and the extended portion and the flange 86 arranged so as to bridge the detection unit 60 and the compensation unit 62 of the core 56, the tip portions of the detection unit 60 and the compensation unit 62 of the core 56. Is clamped together with the mounting plate 46 by the above-mentioned screw 58 in a state where it is clamped without any step and thus without rattling. The end portion of the flange 86 on the fixed short ring 82 side is raised along the fixed short ring 82 to form a rising portion 82A as fixed position adjusting means, which is used for fine adjustment of tilt described later.

With respect to the fixed short ring 82 as well, when an alternating current is applied to the compensation side coil 70 as in the movable short ring 76 described above, an alternating magnetic field is generated in the compensation section 62 of the core 56, which causes an eddy current. Will occur. Therefore, the magnetic path is specified, and the inductance of the compensation side coil 70 is determined to be a certain value. However, when the ambient temperature changes, the inductance of the compensation side coil 70 changes, and the inductance of the detection side coil 68 also changes. Therefore, by comparing the inductances of the two, the detection side due to the change of the environmental temperature is changed. It is possible to compensate for the change in the inductance of the coil 68. As a result, only the rotational position of the rotary shaft 38 of the motor 12 is accurately detected.

As shown in FIG. 4 (B), the above-described core 56 is a core intermediate portion 88 in which thin plates are stacked, and a core intermediate portion 88 that is vertically and closely disposed so as to sandwich the core intermediate portion 88 and has a thin thickness. And both ends 90 of the core that are thicker than the plate. The core intermediate portion 88 and the core both end portions 90 are melted at the welding portions 92 and 94 which are set at a total of two locations, that is, outside the circumferential intermediate portion in the detecting portion 60 of the core 56 and outside the circumferential intermediate portion in the compensation portion 62. The core intermediate portion 88 and the core both end portions 90 are integrated with each other. The penetration depth of the welded portions 92 and 94 is set to a slight amount.

The operation of the present embodiment will be described below through the assembling of the rotational position sensor 10 itself and the assembling of the rotational position sensor 10 to the intermediate upper housing 18.

First, the core 56 itself of the rotational position sensor 10 is configured. That is, the thin plate that constitutes the core intermediate portion 88 and the thick plate that constitutes both end portions 90 of the core are press molded. Next, a predetermined number of thin plates are stacked, and the thick plates are closely attached to both end faces thereof. Then, the core intermediate portion 88 and the core both end portions 90 are integrated by welding at the two welding portions 92 and 94 on the outer periphery. When welding, the penetration depth is set to a slight amount so as not to adversely affect the magnetic field formed in the core 56 when the rotational position sensor 10 is used.

Next, the detection side coil 68, the compensation side coil 70, the movable short ring 76, and the fixed short ring 82 are temporarily attached to the integrated core 56. After that, the core 56 is placed on the columnar or semi-cylindrical support portion of the mounting plate 46, and is fixed by the screw 58 in this state. Thereby, the rotational position sensor 10 itself is configured.

Next, the work of assembling the rotational position sensor 10 to the intermediate upper housing 18 is performed. That is, the claw 52 of the rotational position sensor 10 is locked at a predetermined position of the intermediate upper housing 18 for rough positioning. At the same time, the screw hole 48 of the mounting plate 46 and the hole corresponding to the screw hole 48 formed in the intermediate upper housing 18 are set coaxially, and the movable short ring 76 is fixed to the rotary shaft 38. After that, the rotational position sensor 10 is temporarily fixed with the screw 50.

Next, fine adjustment is performed after the rotational position sensor 10 is assembled. Hereinafter, a method of fine adjustment will be briefly described with reference to FIG. FIG. 5 is a graph showing the characteristics of the rotary position sensor 10 with the horizontal position representing the rotational position θ of the rotor 32 (movable short ring 76) and the vertical axis representing the output voltage V of the rotary position sensor 10. The solid line in the graph is the ideal line.

When the characteristics of the rotational position sensor 10 in the assembled state deviate from the ideal line, zero point adjustment and inclination adjustment are required to match this with the ideal line. At this time, the zero point adjustment is performed by inserting a jig into the U-shaped notch 54 of the mounting plate 46 of the rotational position sensor 10 and slightly changing the mounting position of the mounting plate 46 with respect to the housing 24. Be seen. As a result, the assembly position of the core 56 with respect to the housing 24 is also changed relative to it, and the initial position (start position) of the movable short ring 76 in the detection unit 60 is also changed. Therefore, the zero point of the graph, that is, the initial value of the output voltage at the same rotation position increases or decreases, and the zero point of the graph is finely adjusted.

The tilt adjustment is performed by pressing the rising portion 86 A of the flange 86 of the rotational position sensor 10 and the fixed short ring 82 so as to sandwich them. As a result, the position of the fixed short ring 82 is slightly changed toward or away from the compensating coil 70, and the set value of the magnetic path length in the compensator 62 is changed. Therefore, the inclination of the graph is finely adjusted (for example, when the fixed short ring 82 is pressed in the direction of the arrow A in FIG. 2 from the state of the ideal line, the inclination of the graph changes as shown by the alternate long and short dash line, and conversely. When pressed in the direction of arrow B, the slope of the graph changes as shown by the chain double-dashed line).

As described above, by providing the rising portion 86 A for finely adjusting the fixed position of the fixed short ring 82 and the notch 54 for finely adjusting the assembling position of the core 56, the rotational position sensor 10 is provided. The detection accuracy can be improved at the time of assembly. Further, the work becomes easier as compared with the case where the zero point is adjusted by finely adjusting the assembled state of the movable short ring 76 and the rotary shaft 36.

After that, when the rotational position sensor 10 is in use, the rotational position sensor 10 operates as follows.

When the rotor 32 rotates by a predetermined angle, the movable short ring 76 connected to the rotating shaft 38 rotates accordingly. The rotation of the movable short ring 76 changes the inductance of the detection side coil 68. Further, when the environmental temperature changes, the inductances of the compensation side coil 70 and the detection side coil 68 change equally. Therefore, by comparing the inductances of the two, the inductance change of the detection side coil 68 due to the environmental temperature change is compensated, and only the inductance change due to the rotation of the rotary shaft 38 can be extracted. Then, the amount of rotation of the rotary shaft 38 is calculated and detected from the obtained change in inductance due to the rotation of the movable short ring 76. Based on this detected value, it is checked whether or not the rotor 32 is rotating to the proper position.

Here, in the rotational position sensor 10 of the present embodiment, the core 56 has a core intermediate portion 88 in which the core 56 has a laminated structure of thin plates, and both end portions 90 of the core which are closely arranged on both end surfaces of the core intermediate portion 88. , And both are welded at the welded portions 92, 94, it is possible to prevent the surface of the core from being deformed or peeled off, as compared with the case where the core is composed only of a laminated structure of thin plates. Therefore, it is possible to prevent the deformed and peeled core from coming into contact with the movable short ring 76. Therefore, the reliability of the rotational position sensor 10 can be improved. The effect of improving the reliability of the rotational position sensor 10 is also introduced by the core intermediate portion 88 having a laminated structure of thin plates with less loss due to eddy current.

Further, the welded portions 92, 94 between the core intermediate portion 88 and the core both end portions 90 are provided at two locations on the outer periphery of the core 56, which are opposed to each other in the radial direction, and the penetration depth is also a light amount. Therefore, the magnetic field generated in the core 56 is not adversely affected. Furthermore, the core 56 can be integrated, and the assembling property of the rotational position sensor 10 can be improved.

The motor 12 to which the rotational position sensor 10 described above is attached is arranged in a fuel injection pump of a diesel engine and is used for control related to fuel injection. Is not limited to such a motor, but can be applied to any device that needs to detect the rotational position of the rotational position detection member with high accuracy.

Further, in the present embodiment, the core 56 composed of the core intermediate portion 88 and the core both end portions 90 has been described as an example, but from the viewpoint of preventing deformation and peeling of the core, FIG. , (B) may be used. This core 96 is an improved material, unlike the above-described embodiment in which the deformation and peeling of the core are structurally improved. That is, the core 96 is manufactured by sintering ferrite. In the case of using the core 96, the specific resistance of the core can be increased and the loss due to the eddy current can be reduced, so that the detection accuracy of the rotational position sensor 10 can be improved. Further, since the core 96 is composed of one component, the step of laminating thin plates is not required, and the manufacturability of the core can be improved. Further, since the core 96 is formed by sintering the ferrite, it is possible to prevent the surface of the core from being deformed or peeled off, and the reliability of the rotational position sensor 10 can be improved.

Further, although welding is used as the fixing means in the present embodiment, the invention is not limited to this, and a resin clip or the like that is miniaturized to the extent that the rotation of the movable short ring 76 is not hindered may be used.

Further, in the present embodiment, the welding is performed at the two welding parts 92 and 94, but the present invention is not limited to this, and the number of welding parts may be increased to three or more so as not to adversely affect the magnetic field generated in the core 56. May be. Further, the welding portions 92 and 94 are the outer circumference of the core 56, but may be the inner circumference.

Further, in this embodiment, the U-shaped notch 54 is used as the assembly position adjusting means, but the present invention is not limited to this, and a circular hole, a protrusion or the like may be used, and the core 56 (and thus the rotational position sensor 10). Any configuration can be applied as long as it is a configuration in which the assembly position of the above with respect to the upper housing 20 can be finely adjusted.

Further, in this embodiment, as the fixed position adjusting means, the rising portion 86A is formed on the flange 86, and the rising position 86A and the fixed short ring 82 are sandwiched so that the fixed position of the fixed short ring 82 is finely adjusted. Although the adjustment is made, the present invention is not limited to this, and a screw is screwed into the rising portion 86A in a direction perpendicular to the plane so that the tip of the screw contacts the fixed short ring 82, and the screw is tightened or loosened. The fixed position of the fixed short ring 82 may be finely adjusted.

[0050]

[Effect of the device]

 As described above, in the rotational position sensor according to the present invention as set forth in claim 1, since the core is configured by the core intermediate portion and the core both end portions, the core can be prevented from being deformed or peeled off, and the reliability can be improved. It has an excellent effect that the property can be improved.

Further, in the rotational position sensor according to the present invention as defined in claim 2, the core intermediate portion and both end portions of the core are fixed to each other by the fixing means at least at two positions facing each other in the radial direction of the core. Therefore, there is an excellent effect that the deformation and peeling of the surface of the core can be prevented more reliably.

Further, in the rotary position sensor according to the present invention as set forth in claim 3, since the core is formed by sintering ferrite, not only the stacking step can be eliminated, but also the rotary position sensor according to claim 1. As in the above, the core can be prevented from being deformed or peeled off, so that reliability can be improved. Moreover, since the loss due to the eddy current can be reduced, it has an excellent effect that the detection accuracy of the rotational position sensor can be improved.

Further, since the rotational position sensor according to the present invention according to claim 4 is provided with the fixed position adjusting means for finely adjusting the fixed position of the fixing member, the rotational position in the characteristic of the rotational position sensor can be adjusted. This has the excellent effect that the ratio of the amount of change in the output voltage to the amount of change can be finely adjusted, which in turn improves the detection accuracy.

Further, in the rotational position sensor according to the present invention as set forth in claim 5, since the assembling position adjusting means for finely adjusting the assembling position of the core is provided, the characteristics of the rotational position sensor are the same. This has an excellent effect that the initial value of the output voltage with respect to the rotational position can be increased or decreased, and consequently the detection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a rotary position sensor according to an embodiment of the present invention.

FIG. 2 is a plan view showing a motor in which the rotational position sensor of FIG. 1 is assembled, with an upper housing removed.

3 is an overall sectional view of a motor including the rotational position sensor of FIG.

4 shows a core of the rotational position sensor of FIG. 1, FIG. 4 (A) is a plan view of the core, and FIG. 4 (B) is a side view of the core.

5 is a graph for explaining a method of fine adjustment when the rotational position sensor of FIG. 1 is assembled.

FIG. 6 shows a modified example of the core of FIG. 4, and FIG.
Is a plan view of a core according to a modification, and FIG. 6 (B) is a side view.

FIG. 7 shows a conventional core, FIG. 7 (A) is a plan view of the conventional core, and FIG. 7 (B) is a side view.

[Explanation of symbols]

 10 rotational position sensor 38 rotary shaft (rotated position detecting member) 54 notch (assembly position adjusting means) 56 core 60 detection unit (detection side portion) 62 compensation unit (reference side portion) 68 detection side coil 70 compensation side coil (Reference side coil) 76 Movable short ring (rotating member) 82 Fixed short ring (fixing member) 86A Rising part (fixed position adjusting means) 88 Core middle part 90 Core both ends 92 Welding site 94 Welding site 96 core

Claims (5)

[Scope of utility model registration request] 1. A rotated position detecting member that rotates about an axis, and a circumferentially-separated position of the rotated position detecting member,
A ring-shaped core having a reference side portion forming a reference side magnetic path and a detection side portion forming a detection side magnetic path, a reference side coil wound around the reference side portion, and a winding around the detection side portion. The mounted detection side coil and the rotational position detection member are coaxially connected to each other, and the detection side portion is arranged so as to be relatively rotatable in a direction approaching and separating from the detection side coil. A rotating member that changes the inductance of the detection side coil and a rotating member that is arranged at a position separated from the reference side coil by a predetermined distance in the reference side portion, and compensates for a change in the inductance of the detection side coil due to a change in environmental temperature. A fixed member for detecting the rotational position of the rotated position detection member while comparing the inductances of the reference side coil and the detection side coil. A cactance type rotational position sensor, wherein the core is disposed in close contact with a core middle part formed by laminating a plurality of thin plates and both end faces in the thickness direction of the core middle part, and the thin plate. A rotational position sensor comprising: both ends of a core having a thickness greater than that of the core. 2. The core middle part and both sides of the core are
The rotary position sensor according to claim 1, wherein the cores are fixed to each other by fixing means at least at two positions facing each other in the radial direction. 3. The rotary position sensor according to claim 1, wherein the core is formed by sintering ferrite. 4. A rotated position detecting member that rotates around an axis, and a circumferentially spaced position of the rotated position detecting member,
A ring-shaped core having a reference side portion forming a reference side magnetic path and a detection side portion forming a detection side magnetic path, a reference side coil wound around the reference side portion, and a winding around the detection side portion. The mounted detection side coil and the rotational position detection member are coaxially connected to each other, and the detection side portion is arranged so as to be relatively rotatable in a direction approaching and separating from the detection side coil. A rotating member that changes the inductance of the detection side coil and a rotating member that is arranged at a position separated from the reference side coil by a predetermined distance in the reference side portion, and compensates for a change in the inductance of the detection side coil due to a change in environmental temperature. A fixed member for detecting the rotational position of the rotated position detection member while comparing the inductances of the reference side coil and the detection side coil. A rotational position sensor of the inductance-type, rotational position sensor, characterized in that a fixing position adjusting means for finely adjusting the relative fixed position relative to the reference coil of the fixing member. 5. A rotated position detecting member that rotates around an axis, and a circumferentially-separated position of the rotated position detecting member,
A ring-shaped core having a reference side portion forming a reference side magnetic path and a detection side portion forming a detection side magnetic path, a reference side coil wound around the reference side portion, and a winding around the detection side portion. The mounted detection side coil and the rotational position detection member are coaxially connected to each other, and the detection side portion is arranged so as to be relatively rotatable in a direction approaching and separating from the detection side coil. A rotating member that changes the inductance of the detection side coil and a rotating member that is arranged at a position separated from the reference side coil by a predetermined distance in the reference side portion, and compensates for a change in the inductance of the detection side coil due to a change in environmental temperature. A fixed member for detecting the rotational position of the rotated position detection member while comparing the inductances of the reference side coil and the detection side coil. A rotational position sensor of a transactance type, characterized in that an assembly position adjusting means for finely adjusting a relative assembly position of the core in the circumferential direction with respect to the rotated position detection member is provided. Sensor.