JPH065161B2 - Inductive type position detector with separated stator core - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a primary winding and a secondary winding on the stator side,
The present invention relates to an inductive type (variable magnetoresistive type) position detector in which no winding is provided on the rotor side, and in particular, the pole portions of a plurality of phases provided in the stator portion are configured by independent (separated) magnetic material cores. It is characterized by having done.

[Conventional technology]

As an induction type rotational position detector of the type in which the primary winding and the secondary winding are provided on the stator side and the winding is not provided on the rotor side, a type that produces an output signal having a voltage level according to the rotational position is used. A rotary type differential transformer called a micro thin is known as one, and on the other hand, as a type that outputs an AC signal having an electrical phase angle according to the rotational position, the Japanese Patent Application Laid-Open No. Sho 57-57, filed by the present applicant. There is known a rotation angle detecting device disclosed in Japanese Patent No. 70406.

Conventionally known rotational position detectors of this type are those in which the pole portions of the stator core of a plurality of phases are made of a common magnetic core material, and the magnetic circuit passes from the end portion of a certain pole portion to the rotor portion. Is formed so as to pass through the ends of the other poles and further through the circumference of the stator. This point is shown in FIG. 11 (a), and by pressing one core material (for example, silicon steel plate), each phase A to
An integral stator core plate S ₁ including the pole portion of D in a common material
To form. As is known, a stator core is formed by laminating a large number of such stator core plates S ₁ . R is an eccentric rotor part, and a dotted line shows a magnetic circuit.

[Problems to be solved by the invention]

However, in the conventional stator core as described above, if the size of the detector (diameter of the stator portion) is different, separate core laminated bodies must be prepared according to the size, which causes a manufacturing cost. was there. In particular, in the case of producing a detector by a high-mix low-volume production method, it is necessary to prepare a separate stator core laminated body for each model, which causes a problem that the number of parts is increased as a whole. Also,
Even if the diameter of the stator portion is the same, if the number of poles (number of phases) is different, separate stator core laminated bodies must be prepared, and in this case as well, the same problem as described above was encountered. For example, FIG. 11 (b) shows a stator core plate S ₂ having a larger diameter than that of (a), and FIG. 11 (c) shows a stator core plate S ₃ having a larger number of poles than that of (a). These stator core plate S ₁ to S ₃ is stamped by a separate press mold (therefore must be prepared a press mold separately) must create a stator core by different processes.

The present invention has been made in view of the above points, and enables to use a common stator core member even when the diameter or the number of poles (the number of phases) of the annular or circular stator portion is different,
An object of the present invention is to reduce the number of parts as a whole and to reduce the manufacturing cost when manufacturing a plurality of types of detectors having different sizes and the number of poles.

[Means for solving problems]

The inductive position detector according to the present invention is a ring or a circle as a whole, and includes pole portions of a plurality of phases at predetermined intervals along the circumferential direction, and each pole portion has a primary winding and a secondary winding. Windings are respectively wound, and each pole portion is disposed with a stator portion having a magnetic flux input / output end portion and a gap with respect to each pole portion of the stator portion, and is relative to the stator portion. And a movable body having a structure that changes the magnetic resistance of the magnetic circuit of each of the poles according to the displacement position, and the primary winding is excited by an AC signal to In an induction type position detector in which an AC signal corresponding to the magnetic resistance is induced in a secondary winding of the stator section, each pole section of the stator section has at least two magnetic flux input / outputs having opposite polarities. It has an end for use and consists of an independent magnetic core separated for each phase. Ri, the respective electrode portions formed of the magnetic core of each of the phases at predetermined intervals in the circumferential direction through the supporting member and fixed made to form the stator portion,
At least the pole portions of the stator portion are molded with a molding material such as a synthetic resin, and the molded stator portion includes a moving body including the magnetic flux input / output end portions of the pole portions. The opposing surfaces are formed by cutting into a desired shape, and the primary windings of the respective pole portions of the stator section are individually excited by using a plurality of AC signals whose phases are shifted from each other. A signal obtained by phase-shifting the AC signal on the primary side by an electrical angle corresponding to the displacement position of the moving body is obtained as an output AC signal obtained by combining the AC signals induced in the secondary windings. It is what

[Action]

Since the pole portion of each phase in the stator portion is composed of independent magnetic material cores separated from each other, only one phase of the independent stator core is mass-produced and the desired diameter is obtained. If the desired number is fixed on the supporting member at a predetermined interval, the desired diameter and the desired number of poles (number of phases)
Can be formed having a. Therefore,
The various problems described above can be solved. Also,
At least the respective pole portions of the stator portion are molded with a molding material such as a synthetic resin, and in the molded stator portion, a surface facing the moving body including the magnetic flux input / output end portions of the respective pole portions is formed. Since the finished shape is made into the desired shape by cutting, the separated poles are integrally and tightly fixed, strengthening the strength and preventing rattling during the cutting of the end, It is most suitable when cutting the end part by adapting it to a stator with a diameter of.

Further, since it is a phase shift type position detector, there is an excellent effect that the position can be detected with high accuracy without being affected by the induced voltage level change due to temperature change or disturbance. Therefore, each pole portion of the stator portion has a primary winding and a secondary winding, and the primary windings of each pole portion are individually excited by using a plurality of AC signals that are out of phase with each other. A phase for obtaining a signal obtained by phase-shifting the AC signal on the primary side by an electrical angle corresponding to the displacement position of the moving body as an output AC signal obtained by combining the AC signals induced in the secondary windings of the poles. In the shift type position detector, since the stator portion is configured by the independent stator pole portion for each phase, the common stator core member is used regardless of the stator size, the number of poles, and the number of phases. It becomes possible to assemble position detectors of various specifications,
As a whole, there is an excellent effect that the manufacturing cost can be reduced.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention in a rotary position detector having four-phase (A-D phase) stator pole portions,
(a) is a front view, (b) is a longitudinal cross-sectional view through the A-C phase.

The stator part 1 includes four pole parts 1A to 1D corresponding to four phases A to D arranged at intervals of 90 degrees along the circumferential direction. Each of the pole portions 1A to 1D is composed of a U-shaped one-phase independent magnetic core 10 as shown in an enlarged view in FIG. The magnetic core 10 is made of, for example, a laminated body of silicon steel plates, and has two magnetic flux input / output end portions 10a,
10b and has a primary winding W on two legs 10c and 10d.
_The primary winding W ₂ and the secondary winding W ₂ are wound respectively. Two ends 10
The polarities of a and 10b are opposite to each other, and the flow and direction of the magnetic flux are as shown by solid arrows or broken arrows.

Thus the primary winding W ₁ and the secondary winding W ₂ and four are separated from one another made of a magnetic core 10 having a pole portion 1A~1
Ds are arranged at intervals of 90 degrees on the annular support member 2 and fixed by screwing or other means. Support member 2
The material may be magnetic or non-magnetic. Further, the support member 2 and each of the pole portions 1A to 1D may be molded by a non-magnetic molding material 3 such as synthetic resin so as to have a ring shape as a whole, and thus, the annular stator portion as a whole. 1 is formed. In the front view, the molding material 3
Is assumed to be transparent, the pole portions 1A to 1 to be molded are
D and the support member 2 are shown as visible. In order to make the internal space of the stator part 1 into a perfect circular shape with high accuracy, the circumferential edge 1a of the stator part 1 is finished into a perfect circle by mechanical cutting. By this finishing, the inner circumference of the molding material 3 and the end portions 10a, 10 of the pole portions 1A to 1D are formed.
b is cut into an arc shape as a part of a perfect circle. Therefore, each of the pole portions 1A to 1D before the finishing process, that is, the end portions 10a and 10b of the magnetic core 10 form a linear surface as one surface of the square as shown in FIG. Has an oblique (short arc-shaped) curved surface having a curve corresponding to the size of its inner diameter, as indicated by the dotted line 1a in FIG. The molding material 3 securely fixes the respective pole portions 1A to 1D, and has such an inner circumference (end portions 10a, 10b).
It also has an advantageous effect in facilitating the finishing process. The molding material 3 may be one that molds at least between the respective pole portions.

An eccentric rotor part 4 made of a magnetic material (for example, a laminated body of silicon steel plates) is inserted into the internal space of the stator part 1. The rotor portion 4 is fixed to the shaft 5 and rotates in the internal space of the stator portion 1 as the shaft 5 rotates.

As is apparent, in each of the pole portions 1A to 1D of the stator portion 1, the magnetic flux paths that exit from the one end portion 10a (or 10b) and enter the other end portion 10b (or 10a) face each other through the gap. It passes through a part of the rotor portion 4, and the rotor portion 4 forms a part of the magnetic circuit of each of the pole portions 1A to 1D. At this time, the magnetic resistance in the magnetic circuit of each of the pole portions 1A to 1D is determined according to the size of the gap.
Since the rotor portion 4 is eccentric, the pole portions 1A to 1D
Reluctance varies depending on the rotational position of the rotor unit 4.

The function of the change in the magnetic resistance (permeance in the reciprocal) of each phase A to D with respect to the rotation angle θ of the rotor unit 4 is cos
The characteristics can be set so that the characteristics of θ and B phase are sin θ, C phase is −cos θ, and D phase is −sin θ.

In order to obtain an output AC signal having an electrical phase shift according to the rotation position θ, the magnetic resistance changes differentially A
Exciting the primary winding W ₁ phase and C phase for example a sine signal, a primary winding W ₁ of the B-phase and D-phase magneto resistance changes dynamically differentially excited by cosine signal. And the secondary winding W of A phase and C phase
_The AC signals induced in ₂ are added in anti-phase, and the AC signals induced in the secondary windings W ₂ of B-phase and D-phase are added in anti-phase, and the outputs of both anti-phase additions are added up and output. Get the signal. The output AC signal thus obtained exhibits an electrical phase shift of, for example, sin (ωt−θ) with respect to the excitation signal sinωt, and this phase shift θ corresponds to the rotational position θ. Therefore, if this phase shift θ is measured, data corresponding to the rotational position θ can be obtained.

Even when the size of the detector (diameter of the stator part 1) is larger or smaller than that shown in FIG. 1, the magnetic core 10 having the same size is used as the pole part of the stator part 1 to form the stator part. Can be configured. Of course, in that case, the support member 2 is modified to have a desired size.

Further, even when the number of pole portions provided in the stator portion 1 is different from that shown in FIG. 1, the magnetic core 10 having the same size can be used as the pole portions.

FIG. 3 shows eight pole portions 1A ₁ to 1 in the stator portion 1.
An example in which D ₁ and 1A _{2 to} 1D ₂ are provided at equal intervals (at 45 degrees) is shown. Using eight magnetic cores 10 for one phase shown in FIG. The part 1 is formed (the only difference is the arrangement interval of the pole parts). These eight magnetic core 10 is the pole portion _{1A 1 ~1D 1, 1A 2 ~1D} 2. The rotor portion 6 has an elliptical shape, and the pole portions (1A ₁ and 1A ₂ , 1B ₁ and 1B ₂ , 1C ₁ and 1C ₂ ,
1D ₁ and 1D ₂ ) have the same function of magnetoresistance change, and the excitation signal of the primary winding W ₁ is also the same. That four phases pole 1A ₁ through 1d ₁ of A~D are arranged at 45 degree intervals, further pole of the same phase A~D their respective pole portion 1A ₁ through 1d ₁ 180 ° symmetry 1A ₂ through 1d ₂ is arranged. In this configuration, one cycle of the magnetic resistance change in each pole portion is not one rotation but half rotation. Therefore, the above-mentioned function of change in magnetic resistance is cos2θ, s
in2θ, −cos2θ, −sin2θ, the finally obtained output AC signal is sin (ωt−2θ), and the electrical phase shift angle is twice the rotation angle θ. In the same manner as described above, the A and C phases are excited by sine signals and the B and D phases are excited by cosine signals. In addition, in-phase secondary output signals are added in-phase, and each phase A
The in-phase addition outputs of to D are subjected to the anti-phase addition for the A and C phases, the anti-phase addition for the B and D phases, and finally added and combined, as described above. The advantage of such an 8-pole stator part 1 is that the center of the inner diameter of the stator part 1 and the center of the rotor part 6 are slightly deviated from each other due to a machining error or an assembly error because the same phase is 180 degrees symmetrical. Even if it does, it does not malfunction. This is because the two secondary output signals of the same phase which are symmetrical with respect to 180 degrees are added in the same phase, so that the error signal component due to the mechanical center shift is always canceled.

FIG. 4 shows an example in which the rotor portion 7 is composed of a rod-shaped magnetic body having a double thread structure, using the same 8-pole type stator portion 1 as in FIG. (a) is a front view, and the rotor portion 7 is shown in cross section. (b) is a longitudinal cross-sectional view of the stator portion 1 passing through the A-A phase, and the rotor portion 7 is shown on the side surface. The rotor portion 7 has two ridge portions 7a and 7b having a width P.
It is provided in the form of a thread, and the interval between the recesses between the protrusions 7a and 7b is also P, and one pitch of the two thread is 4P.

The detector of Figure 4 can be used in both rotational and linear positions. In the case of using the rotational position detector, the rotor portion 7 is rotatable and is immovable in the axial direction. In this case, the pole portions 1A _{1 to} 1D ₁ and 1A ₂ related to the rotation angle θ
The function of the magnetic resistance change in 1D ₂ is cos2θ, sin2 as in the case of using the elliptical rotor section 6 shown in FIG.
θ, -cos2θ, -sin2θ,
The output AC signal finally obtained is, for example, sin (ωt-2
θ). When using a linear position detector, the rotor unit 7
(In that case, the name rotor part is not appropriate)
Is non-rotatable and movable in the axial direction. In this case, 2
The same manner as described above magnetoresistance change trigonometric function form shifted 90 degrees from each other a linear displacement as a period of P is the pole portion 1A ₁ through 1d _1,
It occurs in the magnetic circuits of 1A _{2 to} 1D ₂ , respectively. Then, the finally obtained output AC signal is sin (ωT−φ) (where φ
Corresponds to the linear displacement, and when φ = 2π, the linear displacement amount is 2P).

The detector of FIG. 5 realizes the same function as that of FIG. 4 by the rotor portion (or linear moving body portion) 8 having a single thread structure. Although the front view of the stator part 1 is omitted, it is an 8-pole type stator as in FIG. 4 (a). In this case, the pole portion 1A ₁ through 1d ₁ and pole 1A ₂ through 1d ₂ is not on the same circumference, are offset in the axial direction by P. Therefore, the support member 2'is provided with a step difference of P at a semicircle.

The rotor portion 8 having a single thread structure as shown in FIG.
It can also be applied to the four-pole type stator unit 1 as shown in the figure. FIG. 6 shows an example thereof.

The detector shown in FIG. 7 is a detector dedicated to linear position detection, and the linear moving body portion 11 has a ring-shaped protruding portion 1 having a width P.
A plurality of 1a are provided in the axial direction. Although the front view of the stator part 1 is omitted, it is an 8-pole type stator as in FIG. 4 (a). In this case, both pole parts 1A ₁ and 1A ₂ , 1B of the same phase
₁ and 1B ₂ , 1C ₁ and 1C ₂ , and 1D ₁ and 1D ₂ are on the same circumference, but the poles of different phases are sequentially shifted by P / 2 in the axial direction. Therefore, the support member 2 ″ is provided with a step difference of P / 2 at a position of 1/8 circle. FIG. 8 is a developed view showing the arrangement of each pole portion.

By the way, from the relationship between the shapes of the ends 10a and 10b of the stator poles and the shape of the facing surface of the rotor, the function of the magnetic resistance change (permeance change) at each pole is not a simple sine or cosine function, Some 2nd and 3rd harmonic components may be included. Such a third harmonic component is used as a stator pole portion for one phase as shown in FIG.
Two magnetic cores 10-1 and 10 separated by 2
-2, and the rotor portion (or linear moving body portion) having a double-thread screw or a single-thread screw or ring shape as shown in FIGS. 4 to 7. Can be removed by. As shown in FIG.
The spacing between the centers of the two magnetic cores 10-1 and 10-2 is 2P × 5/6 with respect to the spacing 2P between the threads of the rotor portion 9.
The spacing is set by the spacer 12 so that As a result, the function of the magnetic resistance change in one magnetic core 10-1 of the same phase and the function of the magnetic resistance change in the other magnetic core 10-2 deviate by 60 degrees. This is equivalent to adding another stator part in which the phase of the magnetic resistance change is shifted by 60 degrees to the stator part 1 as shown in FIG. 1 to FIG. The third-harmonic component is removed from the output AC signal that is synthesized and output. It has been confirmed that a double-wave component is not included when using an 8-pole stator in which poles of the same phase are arranged at 180-degree symmetrical positions. Therefore, if the double type magnetic core 10 is applied to each pole portion of the eight pole type stator portion 1 as shown in FIG. 9, the second harmonic component and the third harmonic component in the output AC signal can be reliably removed. . In this case, the rotor portion 9 is not limited to the screw-shaped one, and may be two eccentric or elliptical rotors arranged at a predetermined angle (for example, 60 degrees or 30 degrees).

In each of the above embodiments, the end portions 10a, 1 of each stator pole portion are
Although 0b is 2, it may be 3 or more.
Further, in the stator portion 1, the end portions of the respective pole portions are arranged so as to direct the center, and the rotor portion is inserted into the internal space thereof, but the present invention is not limited to this. The parts may be arranged so as to be oriented in the axial direction, and the rotor formed of a swash plate or the like may be arranged so as to face this.
Further, the shape of the stator pole portion (stator core for one phase) may be C-shaped so that the two end portions face each other, and the peripheral edge portion of the rotor portion is inserted therebetween. Further, a plurality of concave and convex teeth are provided on each end 10a, 10b of the stator pole portion, and corresponding concave and convex teeth are also provided on the rotor side so that the magnetic resistance change occurs with the tooth pitch as one cycle. Good.

The entire rotor portion (or linear moving body portion) does not have to be a magnetic body, and only the peripheral edge portion facing the end portion of the stator pole portion may be made of a magnetic body. Further, not only the magnetic body but also the entire rotor portion or the peripheral portion facing the end portion of the stator pole portion may be made of a good conductor such as copper. In that case, when the magnetic flux from the stator pole portion passes through the good conductor portion of the rotor portion (or the linear moving body portion), eddy current loss occurs and the magnetic resistance increases. Therefore, when the rotor portion comes closer to the end of the stator pole portion, the magnetic resistance decreases (permeance increases) when the rotor portion is made of a magnetic material, whereas the rotor portion has good conductivity. If it is made up of a body, its magnetic reluctance increases. As described above, even when a good conductor is used, it is possible to obtain a change in magnetoresistance according to the displacement. Further, the rotor portion (moving body) may be configured by combining a magnetic body and a good conductor. For example, a good conductor such as copper is embedded in the recesses of the rotors (moving bodies) 7, 8 and 9 of the single-thread or double-thread type as shown in the drawing.
The magnetic material and the good conductor are alternately repeated in a spiral shape.

In each of the above-described embodiments, the signals (for example, the sine signal and the cosine signal) whose phases are deviated from each other are used as the excitation signals on the primary side, and the output AC signal whose phase is shifted according to the displacement is obtained. Not limited to such a phase type detector, a voltage type detector that obtains an output signal having a voltage level according to the displacement may be used.

〔The invention's effect〕

As described above, according to the present invention, since each pole portion of the stator portion is composed of independent magnetic cores separated from each other, one phase of the stator pole portion having the same structure and dimensions has different diameter dimensions. It can be used in a plurality of types of stators, and can also be used in a plurality of types of stators having different numbers of poles. Therefore, the trouble of individually manufacturing a stator core for each stator model having a different diameter or the number of poles is solved by the present invention, and only one phase of the stator core is mass-produced. It only needs to be attached to a diameter support member. Therefore, when manufacturing a plurality of types of detectors having different sizes and the number of poles, the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention used as a rotational position detector. (A) is a front view, (b) is a longitudinal sectional view, and FIG. 2 shows a stator pole portion in the same embodiment. FIG. 3 is an enlarged perspective view of a magnetic core used, FIG. 3 is a front view showing another embodiment of the present invention used as a rotational position detector, and FIG. 4 is an invention usable as a rotational position or linear position detector. In yet another embodiment of (a) is a front view, (b) is a vertical sectional view,
FIG. 5 is a longitudinal sectional view showing still another embodiment of the present invention, in which the rotor portion (linear moving body portion) of the same eight-pole type stator portion as in FIG. 4 has a single-thread screw structure. , Sixth
FIG. 8 is a vertical sectional view showing still another embodiment of the present invention, in which the rotor portion (linear moving body portion) has a double thread structure in the same four-pole type stator portion as in FIG. FIG. 7 is a longitudinal sectional view showing still another embodiment of the present invention,
An eight-pole type stator part having a linear moving body part with a ring-shaped projecting structure. Fig. 8 is a development view showing the arrangement of each pole part of the stator part in Fig. 7, and Fig. 9 is a stator for one phase. FIG. 10 is an enlarged perspective view showing another embodiment of the double-structured magnetic material core used as the pole portion, and FIG. 10 is a longitudinal section of a stator portion and a rotor portion (linear moving body portion) using the double-structured magnetic material core.
11 (a) to 11 (c) are front views showing the structure of the stator core in the conventional induction type detector. 1 ... stator, 2,2 ', 2 "... supporting member, 3 ... sealing member, 1A to 1D, 1A ₁ through 1d _1, 1A ₂ through 1d ₂ ...
Pole part, 4, 6 ... Rotor part, 5 ... Rotating shaft, 7, 8, 9 ... Rotor part or linear moving body part, 10 ... Magnetic core used as stator pole part, 10a, 10b ... Flux input / output end part , 11 ... linear moving object portion, 12 ... spacer, W ₁ ... 1 winding, W ₂ ... 2 winding.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-57-108620 (JP, A) JP-A-54-155066 (JP, A) JP-A-49-107758 (JP, A) JP-A-57- 88317 (JP, A) Actually opened Sho 57-151503 (JP, U)

Claims (8)

[Claims] 1. A ring or a circle as a whole, which includes pole portions of a plurality of phases at predetermined intervals along the circumferential direction, and each pole portion has a primary winding and a secondary winding respectively wound. And each of the pole portions is arranged with a stator portion having a magnetic flux input / output end portion through a gap with respect to each of the pole portions of the stator portion, and is relatively displaceable with respect to the stator portion, A moving body having a structure that changes the magnetic resistance of the magnetic circuit of each pole portion according to its displacement position, and the secondary winding of each pole portion is excited by an AC signal. In the induction type position detector in which an AC signal according to the magnetic resistance is induced, each pole portion of the stator portion has at least two magnetic flux input / output end portions having opposite polarities. , Consists of independent magnetic cores separated for each phase, and The stator portion is formed by fixing the pole portions formed of the magnetic cores of the respective phases at predetermined intervals in the circumferential direction, and at least the pole portions of the stator portion are made of synthetic resin. Molded with a molding material such as, and in the molded stator portion, the facing surface of the respective pole portions, including the magnetic flux input / output end portion, facing the moving body is cut and formed into a desired shape. The primary windings of the respective poles of the stator are individually excited by using a plurality of alternating signals having mutually shifted phases, and the alternating current signals induced in the secondary windings of the respective poles are combined. An inductive position detector, wherein a signal obtained by phase-shifting the AC signal on the primary side by an electrical angle corresponding to the displacement position of the moving body is obtained as an output AC signal. 2. The stator portion is characterized in that two pole portions exhibiting the same change in magnetic resistance with respect to the displacement of the movable body are paired and provided at 180-degree symmetrical positions, respectively. Inductive position detector according to claim 1. 3. The induction type position detector according to claim 2, wherein the moving body is a rod having a magnetic body portion projecting in the form of a double-threaded screw in the periphery thereof. 4. The magnetic cores forming the poles of the stator part are composed of first and second magnetic cores separated by a predetermined distance via a spacer. The relationship between each magnetic core and the moving body is set such that the phase of the magnetoresistance change corresponding to each of the second magnetic cores is deviated by a predetermined amount. Inductive type position detector described in the item. 5. The inductive position detector according to any one of claims 1 to 4, wherein the movable body is capable of rotational displacement. 6. The inductive position detector according to any one of claims 1 to 4, wherein the movable body is capable of linear displacement. 7. The moving body according to claim 1, wherein at least a surface of the moving body facing each pole portion of the stator portion includes a magnetic body portion having a predetermined shape. Inductive position detector. 8. The movable body according to claim 1, wherein the movable body includes a good conductor portion having a predetermined shape at least on a surface facing each pole portion of the stator portion. Inductive position detector.