WO2017047783A1

WO2017047783A1 - Linear motor

Info

Publication number: WO2017047783A1
Application number: PCT/JP2016/077537
Authority: WO
Inventors: 博徳黒沢
Original assignee: 日本電産株式会社
Priority date: 2015-09-18
Filing date: 2016-09-16
Publication date: 2017-03-23
Also published as: CN108028594A; JP2017060362A

Abstract

[Problem] To provide a linear motor in which a plurality of coils arranged in an axial direction can be fixed without supporting the coils using a coil bobbin or the like. [Solution] This linear motor part 3 has: a plurality of cylindrical coil units in which three coils 17 arranged coaxially are covered with a resin 18 and hardened; and a movable element 11 that is provided with a permanent magnet 13. The coil units 19 are connected coaxially in an axial direction X. The movable element 11 moves in the axial direction X on an inner peripheral side of the coil units 19. When increasing/decreasing the number of coils 17 in order to change the thrust for moving the movable element 11, the number of coil units 19 may be increased/decreased and the increased/decreased number of coil units 19 connected in the axial direction X. The state in which the coil units 19 are connected in the axial direction X is the same as a state in which the coils 17 are covered with the resin 18 and fixed.

Description

Linear motor

The present invention relates to a three-phase linear motor.

Patent Document 1 discloses a linear motor that includes a stator including a coil of multiples of 3 arranged coaxially and a mover including a permanent magnet, and the mover linearly moves on the inner peripheral side of the coil. . The linear motor of the same document is a three-phase AC motor, and includes a plurality of coil sets including three coils corresponding to the U phase, the V phase, and the W phase as a plurality of coils.

JP 2013-255313 A

Here, it is difficult to fix a plurality of coils arranged in the axial direction unless they are connected in a state where each coil is wound around a coil bobbin or the like.

In view of such problems, an object of the present invention is to provide a linear motor that can fix a plurality of coils arranged in the axial direction without supporting each coil on a coil bobbin or the like.

In order to solve the above problems, a three-phase linear motor of the present invention includes a cylindrical coil unit in which at least three coils arranged coaxially are covered with resin, and a mover including a permanent magnet. The mover moves in the axial direction on the inner peripheral side of the coil unit.

According to the present invention, the plurality of coils are hardened with resin as a coil unit. Therefore, a plurality of coils can be fixed in an axial direction without supporting each coil on a coil bobbin or the like.

In the present invention, the three coils may be a U-phase coil, a V-phase coil, and a W-phase coil, respectively. That is, the three coils of the coil unit function as a U-phase coil, a V-phase coil, and a W-phase coil, respectively, when driving the linear motor.

In the present invention, it is preferable that a plurality of the coil units are provided, and each coil unit is connected in the axial direction. In this way, when the number of coils is increased or decreased to change the thrust for moving the mover, the number of coil units is increased or decreased, and the increased or decreased number of coil units are connected in the axial direction. Good. In addition, since the state in which the plurality of coil units are connected in the axial direction is the same as the state in which the plurality of coils are covered and fixed by the resin, even if the number of coils increases, It can be fixed in an array in the direction.

In the present invention, the resin is preferably BMC (bulk molding compound). If comprised in this way, the heat | fever which generate | occur | produces with a coil can be escaped effectively outside.

According to the present invention, the plurality of coils are covered with resin. Therefore, a plurality of coils can be fixed in an axial direction without supporting each coil on a coil bobbin or the like.

It is an external appearance perspective view of the linear motion rotation drive apparatus provided with the linear motion rotation detector of this invention. It is sectional drawing which cut | disconnected the linear motion rotational drive apparatus of FIG. 1 by the surface containing an axis line. It is a disassembled perspective view of the linear motion rotation drive device of FIG. It is explanatory drawing of a coil unit. It is explanatory drawing of a linear motion rotation detector.

Embodiments of the present invention will be described with reference to the drawings.

(Linear rotation drive device)
FIG. 1 is an external perspective view of a linear motion rotation drive device equipped with a linear motion rotation detector of the present invention. FIG. 2 is a cross-sectional view of the linear motion rotary drive device of FIG. 1 cut along a plane including an axis. FIG. 3 is an exploded perspective view of the linear motion rotary drive device of FIG. As shown in FIG. 1, the direct-acting rotary drive device 1 includes an output shaft 2, a linear motor unit (linear motor) 3 that moves the output shaft 2 along the axis L, and the output shaft 2 rotates about the axis θ. The rotary motor unit 4 and the ball spline bearing (bearing) 5 are provided. The ball spline bearing 5 supports the output shaft 2 so as to be movable in the axial direction and transmits the driving force of the rotary motor unit 4 to the output shaft 2.

Also, the linear motion rotation drive device 1 includes a linear motion rotation detector 7 for detecting the linear motion position and the rotational position of the output shaft 2. The linear rotation detector 7 includes a cylindrical magnetic scale 8 that is coaxially fixed to the output shaft 2 and a magnetic sensor 9 that faces the magnetic scale 8 from a direction orthogonal to the axis L.

The magnetic scale 8, the linear motor unit 3, the rotary motor unit 4, and the ball spline bearing 5 of the linear motion rotation detector 7 are arranged coaxially in this order from one side to the other side in the axial direction. . In the following description, the axial direction is X, and the axis is θ.

(Linear motor part)
As shown in FIG. 2, the linear motor unit 3 includes a mover 11 and a stator 12. The mover 11 includes an output shaft 2 and a plurality of permanent magnets 13 fixed to the outer peripheral surface of the output shaft 2. Each permanent magnet 13 has an annular shape, and an N pole and an S pole are magnetized in the axial direction X. The plurality of permanent magnets 13 face each other with the adjacent permanent magnets 13 facing the same pole. In this example, ten permanent magnets 13 are fixed to the output shaft 2.

The stator 12 is located on the outer peripheral side of the mover 11. As shown in FIGS. 1 and 2, the stator 12 includes a cylindrical coil array 15 having a plurality of coils 17 arranged coaxially, and a wiring board 16 fixed to the coil array 15.

2 and 3, the coil array 15 includes a plurality of cylindrical coil units 19 in which three coils 17 adjacent in the axial direction X are integrally covered with a resin 18 and hardened. Each coil unit 19 is coaxially connected in the axial direction X, thereby forming a coil array 15. In this example, the coil array 15 includes seven coil units 19. Therefore, the coil array 15 includes 21 coils 17.

4 (a) is a perspective view of the coil unit, and FIG. 4 (b) is an explanatory diagram of the manufacturing direction of the coil unit. Each coil unit 19 has a rectangular outline when viewed from the axial direction X. As shown in FIG. 4, each coil unit 19 includes four side surfaces around the axis θ. As shown in FIG. 1, one of the four side surfaces is a substrate fixing surface 19a. As shown in FIG. 3, the start end 17 a and the end end 17 b of each coil 17 in the coil unit 19 are exposed (protruded) from the substrate fixing surface 19 a.

Each coil unit 19 is connected in a posture with the substrate fixing surface 19a directed in the same direction. In this example, each coil unit 19 is connected with an adhesive. The wiring substrate 16 is fixed to a flat surface (substrate fixing surface of the coil array 15) formed by arranging the substrate fixing surfaces 19 a of the coil units 19 in the axial direction X. The wiring board 16 is connected to the start end 17 a and the end end 17 b of each coil 17 of each coil unit 19. In addition, connection of each coil unit 19 can also be performed using a screw | thread etc. FIG.

Here, the linear motor unit 3 is a three-phase motor, and when the linear motor unit 3 is driven, the three coils 17 of each coil unit 19 are respectively a U-phase coil 17 (U) and a V-phase coil 17. (V) functions as a W-phase coil 17 (W). That is, the three coils 17 of each coil unit 19 are a U-phase coil 17 (U), a V-phase coil 17 (V), and a W-phase coil 17 (W), respectively. The linear motor unit 3 moves the mover 11 in the axial direction X while moving the coil 17 to be fed in the axial direction X.

As shown in FIG. 4B, the coil unit 19 includes a rectangular bottom portion 51, a rectangular tube portion 52 that rises from the outer peripheral edge of the bottom portion 51, and a cylindrical portion 53 that protrudes from the bottom portion 51 and extends inside the rectangular tube. Are formed using a mold 54 for molding. More specifically, the three coils 17 are inserted into the mold 54 so that the cylindrical portion 53 is inserted into the hollow portion of each coil 17, and the three coils 17 are stacked in the mold 54. And Thereafter, BMC (bulk molding compound) is filled inside the rectangular tube portion 52, and the coil 17 in the mold 54 is molded by BMC. Here, in this example, BMC is used as the resin 18 for molding the coil 17, but a PPS resin can also be used.

(Rotary motor part)
The rotary motor unit 4 includes a mover 21 and a stator 22. The mover 21 includes a hollow nut shaft 23 through which the output shaft 2 passes. As shown in FIG. 3, the nut shaft 23 includes a small-diameter cylindrical portion 23a and a large-diameter cylindrical portion 23b having a larger diameter than the small-diameter cylindrical portion 23a. The large diameter cylindrical portion 23b is continuously provided on the ball spline bearing 5 side of the small diameter cylindrical portion 23a. The mover 21 includes a cylindrical yoke 24 fixed to the outer peripheral surface of the small-diameter cylindrical portion 23 a of the nut shaft 23, and a cylindrical permanent magnet 25 fixed to the outer peripheral surface of the yoke 24. The permanent magnet 25 has a cylindrical shape, and a plurality of N and S poles are alternately magnetized around the axis θ (circumferential direction).

The stator 22 is located on the outer peripheral side of the permanent magnet 25. The stator 22 includes a cylindrical yoke 26 surrounding the permanent magnet 25 from the outer peripheral side, and a plurality of coils 27 fixed to the inner peripheral surface of the yoke 26. Each coil 27 is fixed to the yoke 26 in such a posture that its hollow portion is oriented in the radial direction orthogonal to the axis L. The plurality of coils 27 are arranged around the axis line θ. In this example, the stator 22 includes six coils 27. The yoke 26 is held by the case 28 from the outer peripheral side. The contour shape when the case 28 is viewed from the axial direction X is a square.

The nut shaft 23 rotates around the axis line θ by feeding power to the coil 27. Here, a ball nut 31 constituting the ball spline bearing 5 is disposed on the inner peripheral side of the large-diameter cylindrical portion 23 b of the nut shaft 23. In FIG. 2, the balls constituting the ball spline bearing 5 and the splines provided on the output shaft 2 are omitted. The rotation of the nut shaft 23 is transmitted to the output shaft 2 via the ball nut 31. Therefore, when the rotary motor unit 4 is driven, the output shaft 2 rotates. The large diameter cylindrical portion 23 b of the nut shaft 23 is covered with a bearing case 32. The contour shape when the bearing case 32 is viewed from the axial direction X is a square.

(Linear rotation detector)
FIG. 5 is an explanatory diagram of the linear motion rotation detector 7. As shown in FIG. 5, the magnetic scale 8 is cylindrical. As shown in FIGS. 1 to 3, the magnetic scale 8 is coaxially fixed to the output shaft 2 in a state where the output shaft 2 passes through the center hole. The magnetic scale 8 moves linearly in the axial direction X integrally with the output shaft 2 and rotates about the axis θ.

The magnetic scale 8 includes a cylindrical member 35 that is a fixed portion to the output shaft 2 and an annular permanent magnet 36 that is fixed to the outer peripheral side of the cylindrical member 35. The permanent magnet 36 is a lattice in which S poles and N poles are alternately arranged in the axial direction X on the circumferential surface around the axis θ, and S poles and N poles are alternately magnetized around the axis θ. A magnetized pattern 37 is provided. Here, the lattice-like magnetized pattern 37 is provided with a plurality of axial tracks 37a extending in the axial direction X in parallel in the axial direction θ, with S poles and N poles alternately arranged in the axial direction X. The lattice-like magnetized pattern 37 includes a plurality of circumferential tracks 37b arranged in parallel in the axial direction X, with S and N poles alternately arranged around the axial line θ and extending around the axial line θ.

The magnetic sensor 9 includes a sensor substrate 40 facing the magnetic scale 8 from a direction orthogonal to the axis L in a posture parallel to the axis L. The magnetic sensor 9 includes a first magnetoresistive element (first magnetic detecting element) 41 for detecting a linear motion position formed on a substrate surface 40a facing the magnetic scale 8 in the sensor substrate 40, and a first rotating sensor for detecting a rotational position. Two magnetoresistive elements (second magnetic detection elements) 42 are provided.

The first magnetoresistive element 41 has its magnetosensitive direction in the axial direction X. Therefore, the first magnetoresistive element 41 includes a plurality of magnetized patterns 37 of the magnetic scale 8 and a plurality of rows of axial tracks 37a extending in the axial direction X with S poles and N poles alternately arranged around the axis θ. The change in the magnetic field when the magnetic scale 8 moves is detected. Here, in the plurality of axial tracks 37a, the first magnetoresistive element 41 rotates at a boundary portion (a portion where the N pole and the S pole are adjacent) between two axial tracks 37a adjacent to each other around the axis θ. Detect magnetic field. The first magnetoresistive element 41 detects a rotating magnetic field using the saturation sensitivity region of the magnetoresistive element. In other words, the first magnetoresistive element 41 detects a rotating magnetic field in which the direction in the in-plane direction changes at the boundary portion by applying a magnetic field intensity at which the resistance value is saturated while applying a current to a magnetoresistive pattern described later. .

The second magnetoresistive element 42 has its magnetic sensing direction oriented around the axis θ (circumferential direction). Therefore, the second magnetoresistive element 42 has the magnetization pattern 37 of the magnetic scale 8 in the axial direction X with the circumferential track 37b extending in the axial direction θ by alternately arranging the S and N poles around the axial line θ. As having a plurality of rows, a change in the magnetic field when the magnetic scale 8 rotates is detected. Further, the second magnetoresistive element 42 is a rotating magnetic field generated at a boundary portion (a portion where the N pole and the S pole are adjacent) between two circumferential tracks 37b adjacent in the axial direction X in the plurality of circumferential tracks 37b. Is detected. Further, the second magnetoresistive element 42 detects the rotating magnetic field using the saturation sensitivity region of the magnetoresistive element. That is, the second magnetoresistive element 42 detects a rotating magnetic field in which the direction in the in-plane direction changes at the boundary portion by applying a magnetic field intensity at which the resistance value is saturated while passing a current through a magnetoresistive pattern to be described later. .

In this example, the magnetoresistive pattern of the first magnetoresistive element 41 and the magnetoresistive pattern of the second magnetoresistive element 42 formed on the sensor substrate 40 are laminated.

(Function and effect)
According to this example, the plurality of coils 17 are covered with the resin 18. Therefore, a plurality of coils 17 can be fixed in the axial direction X without supporting each coil 17 on a coil bobbin or the like.

Further, in this example, the linear motor unit 3 includes a cylindrical coil unit 19 in which three coils arranged coaxially are hardened with a resin 18. Therefore, when the number of coils 17 is increased or decreased in order to change the thrust for linearly moving the mover 11, the number of coil units 19 is increased or decreased, and the increased or decreased number of coil units 19 are connected in the axial direction. That's fine. Here, the state in which the plurality of coil units 19 are connected in the axial direction is the same as the state in which the plurality of coils 17 are covered and fixed by the resin 18. Therefore, even when the number of the coils 17 arranged coaxially is increased or decreased, it is not necessary to create a new molding die 54 corresponding to the arrangement length of the coils 17 and mold the coils 17. That is, according to the present example, a mold 54 for molding the three coils 17 arranged coaxially with the resin 18 may be prepared, and more than three coils 17 may be covered with the resin 18. The mold 54 for hardening is not necessary. Therefore, when manufacturing a plurality of linear motors having different thrusts, the cost of the mold 54 can be suppressed.

In this example, since the coil 17 is covered and hardened using BMC as the resin 18, the heat generated in the coil 17 is easily released to the outside.

(Other embodiments)
In the above example, each coil unit 19 has a rectangular outline shape when viewed from the axial direction X, but may have a shape other than a rectangular shape. In the above example, the three coils 17 are coiled together with a resin 18 to form a single coil unit 19, but three or more coils 17, for example, six coils 17 are coiled together with a resin 18. One coil unit can also be used.

3. Linear motor part (linear motor)
DESCRIPTION OF SYMBOLS 11 ... Movable element 13 of linear motor part ... Permanent magnet 17 of linear motor part ... Coil 18 of linear motor part ... Resin 18
19 ... Coil unit L ... Axis

Claims

A cylindrical coil unit in which at least three coils arranged coaxially are covered with resin, and
A mover comprising a permanent magnet,
The three-phase linear motor characterized in that the mover moves in the axial direction on the inner peripheral side of the coil unit.
In claim 1,
The three coils are a U-phase coil, a V-phase coil, and a W-phase coil, respectively.
In claim 1 or 2,
A linear motor comprising a plurality of the coil units, wherein each coil unit is connected in the axial direction.
In any one of claims 1 to 3,
The linear motor, wherein the resin is BMC.