JP2507287Y2 - Rotational position sensor - Google Patents

Description

[Detailed description of the device]

[0001]

[Industrial application] The present invention relates to a rotational position sensor,
In particular, the present invention relates to an inductance type rotational position sensor that detects a rotational position based on a change in the inductance of a coil.

[0002]

2. Description of the Related Art Among rotational position sensors for detecting the rotational position of a motor or the like, an inductance type rotational position sensor for detecting the rotational position based on a change in the inductance of a coil is wound around the outer periphery of a core and excited by a high frequency. There is a coil provided with a detection side coil and a movable short ring that can move relative to the core.

In this type of rotational position sensor, the core is formed in a ring shape concentric with the motor rotating shaft, and the movable short ring is connected to the motor rotating shaft and rotates integrally therewith. That is, the position where the magnetic flux generated in the detection side coil is cut changes depending on the moving position of the movable short ring that rotates together with the motor rotation shaft, and the inductance of the detection side coil changes. Further, in this type of rotational position sensor, the compensation side coil is arranged adjacent to the detection side coil, and a fixed short ring is fixed at a predetermined position of the core corresponding to the compensation side coil. The compensation side coil and the fixed short ring have a role of compensating for the change in the inductance of the detection side coil due to temperature or the like.

Thus, the rotational position of the motor rotating shaft can be detected based on the inductance value while comparing the inductances of the detection side coil and the compensation side coil.

By the way, in such a conventional inductance type rotary position sensor, a screw for fixing the fixed short ring to the core and an assembling space for the screw for fixing the core itself are indispensable.
Since the core around which the detection side coil and the compensation side coil are wound as described above is simply formed in a ring shape concentric with the motor rotating shaft, the movable range of the movable short ring is greatly limited. In other words, by securing the installation space for the fixed screw, etc., the movable range of the movable short ring is eroded, and as a result, the rotational position can be detected over a wide range (large angle) of the motor rotation shaft. There was a difficult drawback. Therefore, in this case, the range of application of the rotational position sensor also becomes small.

On the other hand, in such a conventional inductance type rotary position sensor, the windings of the detecting side coil and the compensating side coil as described above are wound in a bare state or in a state in which an impregnating agent is applied, and then, It is connected to the terminal simply by soldering. Therefore, there is a high possibility that the winding will be broken due to vibration, a dent at the time of assembly, or a change in environmental temperature, and there is a drawback that reliability and durability are relatively low.

[0007]

In consideration of the above facts, the present invention can detect the rotational position over a wide rotational angle range in the inductance type rotational position sensor, and
The objective is to obtain a rotational position sensor that also has improved reliability and durability.

[0008]

According to a first aspect of the present invention, there is provided a rotational position sensor, which is a detection side coil wound around an outer periphery of a ring-shaped core concentric with a rotational position detection member and excited at a high frequency. And a compensation side coil that is wound around the outer periphery of the core adjacent to the detection side coil and is excited at a high frequency,
A core that is coaxially connected to the rotated position detection member and is rotatably disposed relative to the core corresponding to the detection side coil, and that corresponds to the detection side coil by rotation of the rotated position detection member; A movable short ring that relatively moves to change the inductance of the detection side coil, and a movable short ring fixed to a predetermined position of the core corresponding to the compensation side coil, the change of the inductance of the detection side coil due to the movement of the movable short ring. A fixed short ring for compensation, and an inductance type rotational position sensor for detecting a rotational position while comparing the inductances of the detection side coil and the compensation side coil, wherein the center of the ring of the core corresponding to the compensation side coil is The movable short ring is eccentrically separated from the center of rotation by a predetermined distance. It is characterized in that it has an elliptical shape as a whole the core.

The rotary position sensor of the invention according to claim 2 is
The detection-side coil and the compensation-side coil of the rotary position sensor according to claim 1, wherein a winding portion of the coil, a connecting portion for connecting the winding end portion to the terminal, and a crossover wire between the winding portion and the connecting portion. It is characterized in that the part is covered with a resin material and integrally insert-molded.

[0010]

In the rotary position sensor according to the present invention, the inductance of the detection side coil changes depending on the moving position of the movable short ring that rotates together with the motor rotation shaft, and the inductances of the detection side coil and the compensation side coil are compared. However, the rotational position is detected by compensating the change in the output value with respect to temperature and the like.

Here, the ring center of the core corresponding to the compensation side coil is the rotation center of the movable short ring (that is, the rotation axis of the rotated position detecting member, in other words, the ring center of the core corresponding to the detection side coil). ) Is eccentric with a predetermined gap from the core, and the core is formed into an elliptical shape as a whole, so the screw for fixing the fixed short ring to the core and the screw for fixing the core itself are assembled. The movable range of the movable short ring is prevented from being eroded by the space, and a large movable range of the movable short ring can be secured. Therefore, as a result, the rotational position can be detected over a wide range (large angle), and the range of application of the rotational position sensor is expanded.

In the rotational position sensor according to the second aspect, the detection side coil and the compensation side coil have a winding portion of the coil, a connecting portion for connecting the winding end portion to the terminal, and the winding portion and the connecting portion. Since the crossover wire portion is covered with a resin material and is integrally insert-molded,
Winding is prevented from breaking due to vibration and changes in ambient temperature, improving reliability and durability.

[0013]

1 is a front view of a rotary position sensor 10 according to the present invention. Further, FIG. 3 shows an overall sectional view of a motor 60 in which the rotational position sensor 10 is used.

The rotational position sensor 10 includes a core 12, a detection side coil 14 and a compensation side coil 16. Core 1
2 is composed of a detection unit 18 and a compensation unit 20. As shown in detail in FIG. 2, the detecting portions 18 of the core 12 are formed in inner and outer sides and are concentric with each other, and the compensating portions 20 of the core 12 are located in inner and outer sides, respectively. However, they are formed in a concentric ring shape, and further, the base ends of the detection unit 18 and the compensation unit 20 are integrally connected to each other to form a mounting base 22. Here, the ring center O ₂ of the ring center O ₁ and the compensator 20 of the detector 18 are spaced apart a predetermined distance L, Thus, the core 12 is formed into an elliptical shape as a whole.

Mounting holes 24 and 26 are formed at the tips of the detecting portion 18 and the compensating portion 20 of the core 12, respectively.
A mounting hole 28 is formed in the mounting base 22.
The core 12 is arranged such that the ring center O ₁ of the detecting portion 18 is at the same center as the rotating shaft 62 of the motor 60 as the rotated position detecting member, and the screws 30 are fitted into the respective mounting holes 24, 26, 28. Has been fixed.

A detection side coil 14 and a compensation side coil 16, which will be described in detail later, are attached to the base ends of the detection portion 18 and the compensation portion 20 of the core 12 (on the sides of the mounting base portion 22). The detection side coil 14 and the compensation side coil 16 are
Each is excited by high frequency.

A movable short ring 32 is arranged on the outer periphery of the detecting portion 18 of the core 12. The movable short ring 32 is formed with a pair of rectangular through holes 34 corresponding to the detecting portions 18 of the core 12, and the detecting portions 18 are relatively movably inserted into the through holes 34. Further, one end of the movable short ring 32 is fixed to the rotating shaft 62 of the motor 60 by a set screw 36. Therefore, the movable short ring 32 is always integrated with the rotary shaft 62 of the motor 60 and is rotationally moved along the detecting portion 18 of the core 12. As a result, when the position of the movable short ring 32 is changed, the position where the magnetic flux generated in the detection side coil 14 is cut is changed and the inductance of the detection side coil 14 is changed. In addition, the movable short ring 3
The center of rotation 2 (the rotation shaft 62 of the motor 60) is the core 12
It is in a state of being separated from the ring center O ₂ of the compensator 20 by a predetermined distance L.

On the other hand, a fixed short ring 38 is arranged on the outer periphery of the compensation portion 20 of the core 12. The fixed short ring 38 is located at a predetermined position of the compensator 20 (for example, a position corresponding to half the moving range of the movable short ring 32).
It is fixed using the mounting holes 24 and 26 and the screw 30 described above. This fixed short ring 38 is the compensation side coil 1.
6 has the role of compensating for the change in the inductance of the detection side coil 14 due to temperature and the like. Thereby, the rotational position of the rotary shaft 62 of the motor 60 can be detected based on the inductance value while comparing the inductances of the detection side coil 14 and the compensation side coil 16.

The above-mentioned detection side coil 14 and compensation side coil 16 have basically the same structure. Here, a perspective view of the detection side coil 14 is shown in FIG.
8 to 8 are a plan view, a side view, a front view and a back view of the detection side coil 14, respectively. Further, FIGS. 9 to 11 show the internal structure of the detection side coil 14, and FIG. 12 shows an enlarged view of the main parts.

Detection side coil 14 (and compensation side coil 1
6) has a structure in which terminals 42 are attached to both sides of the bobbin 40.
2, one end of the winding wire 44 is spot-welded and connected, and then wound around the bobbin 40 to form a coil portion 46, and the other end portion of the winding wire 44 is connected to the other terminal 42.
Spot welded to and connected to. Further, here, in the connection portion of each terminal 42, as shown in detail in FIG. 12, the winding 44 is connected with a slack to form a crossover wire portion 48. A caulking portion 50 is provided at a lower end portion of each terminal 42, and a lead wire 52 is connected to the caulking portion 50.

The detecting side coil 14 and the compensating side coil 16 having such an internal structure are respectively provided in the coil portion 4.
6. A connecting portion for connecting the end portion of the winding wire 44 to the terminal 42, the crossover wire portion 48 and the caulking portion 50 are integrally molded by being covered with epoxy resin. Therefore, the structure is such that each of these parts is not exposed to the outside.

Next, the operation of this embodiment will be described. In the rotational position sensor 10 having the above configuration, the inductance of the detection side coil 14 changes depending on the moving position of the movable short ring 32 that rotates together with the rotation shaft 62 of the motor 60, and the inductance of the detection side coil 14 and the compensation side coil 16 further changes. While comparing, the change in the output value with respect to the temperature and the like is compensated, and the rotational position is detected.

Here, the core 12 corresponding to the compensating side coil 16, that is, the ring center O ₂ of the compensating portion 20 of the core 12
Is from the rotation center of the movable short ring 32 (that is, the rotation axis of the rotation shaft 62 of the motor 60, in other words, the core 12 corresponding to the detection side coil 14, that is, the ring center O ₁ of the detection unit 18 of the core 12). Since the core 12 is eccentrically separated by a predetermined distance L and the core 12 is formed in an elliptical shape as a whole, an assembling space of the screw 30 for fixing the fixing short ring 38 to the core 12 or fixing the core 12 itself. Therefore, the movable range of the movable short ring 32 is not eroded. Therefore, it is possible to secure a large movable range of the movable short ring 32. Therefore, as a result, the rotational position of the rotary shaft 62 of the motor 60 can be detected over a wide range (large angle), and the range of application of the rotational position sensor 10 is expanded.

Further, in the rotational position sensor 10, the detecting side coil 14 and the compensating side coil 16 respectively have a coil portion 46, a connecting portion for connecting the end portion of the winding wire 44 to the terminal 42, a crossover wire portion 48 and a caulking portion. Since 50 is integrally molded by being covered with epoxy resin, the winding wire 44 is subject to vibrations, dents during assembly, or environmental temperature changes.
Is prevented from breaking, and reliability and durability are improved. Further, compared to the case where the winding wire 44 is coated with an impregnating agent as in the conventional case and wound, the variation in the manufacturing process can be greatly reduced, and the quality is stable.

In the present embodiment, the movable short ring 32 arranged so as to be movable relative to the detecting portion 18 of the core 12 is fixed to the rotary shaft 62 of the motor 60 by the set screw 36. Not limited to this, the rotary shaft 6
The fixed position of the movable short ring 32 with respect to 2 may be changed. That is, as shown in FIGS. 13 to 18, the elongated hole 3 is formed in the base portion 33 of the movable short ring 32.
5 may be formed so that the fixed position of the movable short ring 32 can be changed, whereby the inclination angle with respect to the core 12 (detection unit 18) can be changed. In this case, the rotational position can be detected more accurately.

That is, when the movable short ring 32 is simply fixed by the set screw 36, for example, the iron loss of the core 12, the eddy current loss of the movable short ring 32,
The inductance of the detection side coil 14 does not change in proportion to the moving angle of the movable short ring 32 with respect to the core 12 under the influence of the mutual inductance between the detection side coil 14 and the compensation side coil 16, etc. As indicated by the alternate long and short dash line, it does not change linearly. Therefore, in this case, it is necessary to repeat trial and error so that the inductance of the detection side coil 14 changes linearly while changing the shape and material of the core 12.

However, as described above, by forming the elongated hole 35 so that the fixed position of the movable short ring 32 can be changed, the core 12 (detection portion 18) of the movable short ring 32 as shown in FIGS. It is possible to easily adjust the change characteristic of the inductance by changing the inclination angle with respect to (1). Thereby, the detection side coil 14
Inductance of movable core 12 of short ring 32
It can be set so as to change in proportion to the movement angle with respect to, and to change linearly as shown by the solid line in FIG. 19, and the rotational position can be detected more accurately.

[0028]

As described above, the rotational position sensor according to the present invention has an excellent effect that the rotational position can be detected over a wide range of rotational angles and that reliability and durability are improved. There is.

[Brief description of drawings]

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

FIG. 2 is a plan view of the core of the rotational position sensor.

FIG. 3 is an overall sectional view of a motor in which a rotational position sensor is used.

FIG. 4 is a perspective view of a detection side coil of the rotational position sensor.

FIG. 5 is a plan view of a detection side coil.

FIG. 6 is a side view of a detection side coil.

FIG. 7 is a front view of a detection side coil.

FIG. 8 is a rear view of the detection side coil.

FIG. 9 is a side view showing the internal structure of the detection-side coil before resin-integral molding.

FIG. 10 is a front view showing the internal structure of the detection side coil before resin integral molding.

FIG. 11 is a plan view showing the internal structure of the detection side coil before resin integral molding.

FIG. 12 is a view showing a terminal portion of a detection side coil.
3 is an enlarged plan view of a main part of FIG.

FIG. 13 is a perspective view of a movable short ring according to another embodiment in a normal fixed state.

FIG. 14 is a front view of a movable short ring according to another embodiment in a normal fixed state.

FIG. 15 is a plan view of a movable short ring according to another embodiment in a normal fixed state.

FIG. 16 is a perspective view of a movable short ring according to another embodiment in an inclined fixed state.

FIG. 17 is a front view of a movable short ring according to another embodiment in an inclined fixed state.

FIG. 18 is a plan view of a movable short ring according to another embodiment in an inclined fixed state.

FIG. 19 is a diagram showing a change characteristic of inductance with respect to a rotation angle of a movable short ring according to another embodiment.

[Explanation of symbols]

 10 Rotation Position Sensor 12 Core 14 Detection Side Coil 16 Compensation Side Coil 18 Detection Section 20 Compensation Section 32 Movable Short Ring 38 Fixed Short Ring 62 Rotation Shaft (Rotated Position Detection Member)

Claims (2)

(57) [Scope of utility model registration request] 1. A detection side coil wound around the outer periphery of a core formed in a ring shape concentric with a rotated position detection member and excited at a high frequency, and wound around the outer periphery of the core adjacent to the detection side coil. The compensation side coil mounted and excited at a high frequency and the coaxially connected to the rotated position detecting member are arranged so as to be rotatable relative to the core corresponding to the detecting side coil. A movable short ring that moves relative to the core corresponding to the detection side coil by rotation to change the inductance of the detection side coil, and the movable short ring fixed to a predetermined position of the core corresponding to the compensation side coil. A fixed short ring for compensating for a change in the inductance of the detection side coil due to the movement of the detection side coil, and an inductor of the detection side coil and the compensation side coil. In an inductance-type rotational position sensor that detects the rotational position while comparing the rotational positions, the ring center of the core corresponding to the compensation side coil is eccentric with a predetermined distance from the rotational center of the movable short ring, A rotary position sensor, wherein the core is formed in an elliptical shape as a whole. 2. In the detection side coil and the compensation side coil, a winding portion of the coil, a connecting portion for connecting the winding end portion to a terminal, and a crossover portion between the winding portion and the connecting portion, The rotary position sensor according to claim 1, wherein the rotary position sensor is covered with a resin material and integrally insert-molded.