JP7295432B2 - Manufacturing method for stator and eddy current reduction gear - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a method of manufacturing a stator for an eddy current speed reducer, and more specifically, has an annular storage space that is open on the outer or inner peripheral side, and stores a permanent magnet row in the storage space. The present invention relates to a method for manufacturing a stator. The present disclosure also relates to a method of manufacturing an eddy current reduction gear using this stator.

BACKGROUND ART Conventionally, an eddy current speed reducer is used as an auxiliary brake for large vehicles such as trucks and buses. An eddy current reduction gear normally includes a cylindrical braking member fixed to a rotating shaft of a vehicle, and a stator disposed inside the braking member and fixed to a non-rotating portion of the vehicle. The stator has a plurality of permanent magnets and a plurality of pole pieces inside. By changing the position of the permanent magnet with respect to the pole piece, it is switched between a damped state and a non-damped state.

When the eddy current speed reducer is in a braking state, magnetic flux from the permanent magnet reaches the braking member via the pole piece, generating eddy currents on the surface of the braking member. Due to the interaction between this eddy current and the magnetic flux, braking torque is generated in the braking member in the direction opposite to the direction of rotation. On the other hand, when the eddy current speed reducer is in a non-braking state, a magnetic circuit is formed between the permanent magnet and the pole piece, and the magnetic flux from the permanent magnet does not reach the braking member. Therefore, no braking torque is generated in the braking member.

For example, Patent Literatures 1 and 2 disclose an eddy current speed reducer having two types of permanent magnets. In these reduction gear transmissions, a plurality of first permanent magnets are arranged in the circumferential direction and a plurality of second permanent magnets are arranged in the circumferential direction within the hollow annular case of the stator. Each of the second permanent magnets is arranged radially outside the first permanent magnets and embedded in an annular magnetic member. This magnetic member forms a pole piece.

JP-A-2004-32927 JP 2007-82333 A

In the eddy current speed reducer of Patent Documents 1 and 2, a pole piece is formed by an annular magnetic member. Such a magnetic member usually has an outer diameter and an inner diameter of several hundred mm, and each of the outer diameter and inner diameter is given a manufacturing tolerance of about ±1 mm. Therefore, in the magnetic member, the dimensional accuracy of the outer diameter, the inner diameter, and the thickness determined by the difference between them tends to be low. If the dimensional accuracy of the magnetic member as the pole piece is low, there is a possibility that the target performance cannot be obtained in the eddy current speed reducer to which the stator including this magnetic member is applied.

An object of the present disclosure is to provide a stator manufacturing method capable of realizing pole piece portions with high dimensional accuracy.

A manufacturing method according to the present disclosure is a manufacturing method of a stator for an eddy current reduction gear. The stator has an annular accommodation space inside which is open on the outer peripheral side or the inner peripheral side. A permanent magnet array is housed in the housing space. A stator manufacturing method comprises the steps of: preparing elongated pole piece members; preparing a stator case for forming an accommodation space; and a step of winding. The pole piece member includes a plurality of pole piece portions arranged in parallel with each other at intervals, and a connecting portion connecting the pole piece portions.

According to the present disclosure, it is possible to achieve a pole piece portion with high dimensional accuracy.

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of an eddy current speed reducer according to a first embodiment. 2 is a partial cross-sectional view of the reduction gear shown in FIG. 1. FIG. FIG. 3A is a schematic diagram for explaining a method of manufacturing a stator included in the reduction gear transmission shown in FIGS. 1 and 2. FIG. FIG. 3B is a schematic diagram for explaining a method of manufacturing the stator included in the reduction gear shown in FIGS. 1 and 2. FIG. FIG. 3C is a schematic diagram for explaining a method of manufacturing the stator included in the reduction gear transmission shown in FIGS. 1 and 2. FIG. FIG. 3D is a schematic diagram for explaining a method of manufacturing the stator included in the reduction gear shown in FIGS. 1 and 2. FIG. FIG. 3E is a schematic diagram for explaining a method of manufacturing the stator included in the reduction gear shown in FIGS. 1 and 2. FIG. FIG. 4 is a partial cross-sectional view showing a schematic configuration of an eddy current speed reducer and a stator according to the second embodiment. 5A is a schematic diagram for explaining a method of manufacturing the stator shown in FIG. 4. FIG. 5B is a schematic diagram for explaining a method of manufacturing the stator shown in FIG. 4. FIG. 5C is a schematic diagram for explaining a method of manufacturing the stator shown in FIG. 4. FIG. FIG. 6 is a schematic diagram for explaining a method of manufacturing a stator for an eddy current speed reducer according to the third embodiment. FIG. 7 is a partial cross-sectional view showing a schematic configuration of an eddy current speed reducer according to a fourth embodiment. FIG. 8 is a schematic diagram for explaining a modification of the above embodiment. FIG. 9 is a schematic diagram for explaining a modification of the above embodiment.

A manufacturing method according to an embodiment is a manufacturing method of a stator for an eddy current reduction gear. The stator has an annular accommodation space inside which is open on the outer peripheral side or the inner peripheral side. A permanent magnet array is housed in the housing space. A stator manufacturing method comprises the steps of: preparing elongated pole piece members; preparing a stator case for forming an accommodation space; and a step of winding. The pole piece member includes a plurality of pole piece portions arranged in parallel with each other at intervals, and a connecting portion connecting the pole piece portions.

According to the above embodiment, when manufacturing the stator for the eddy current speed reducer, the elongated pole piece member including the plurality of pole piece portions is wound around the stator case. In the elongated pole piece member, unlike the annular magnetic member, it is not necessary to control the inner diameter and the outer diameter, and the thickness of the pole piece portion may be directly controlled. The thickness of the pole piece portion is very small compared to the inner and outer diameters of the annular magnetic member, and very little manufacturing tolerance is given. Therefore, by manufacturing the stator using long pole piece members, it is possible to realize pole piece portions with high dimensional accuracy.

In the pole piece member, the connecting portion preferably connects the pole piece portions on the opening side of the accommodation space.

The connecting portion may connect the pole piece portions on the side opposite to the opening of the accommodation space.

The pole piece member may be formed of a plurality of metal plates laminated in the width direction of the pole piece member.

The pole piece member may be formed of a plurality of metal plates laminated in the thickness direction of the pole piece member.

A method for manufacturing an eddy current reduction gear for a vehicle according to an embodiment includes the steps of preparing a stator manufactured by the manufacturing method described above, attaching the stator to a non-rotating portion of a vehicle, and mounting a cylindrical braking member on the outside of the stator. or inside and attaching the braking member to the rotating shaft of the vehicle.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding configurations are denoted by the same reference numerals, and the same description will not be repeated.

<First embodiment>
[Configuration of eddy current speed reducer]
FIG. 1 is a longitudinal sectional view showing a schematic configuration of an eddy current speed reducer 100 according to the first embodiment. The speed reducer 100 is used, for example, as an auxiliary brake for vehicles such as trucks and buses. A longitudinal section is a section taken along a plane including the axis X of the rotating shaft 200 of the vehicle in which the reduction gear transmission 100 is used. The rotating shaft 200 is, for example, a propeller shaft or a drive shaft. Hereinafter, the direction in which the axis X extends will be referred to as the axial direction, and the circumferential and radial directions of the ring or cylinder centered on the axis X will simply be referred to as the circumferential and radial directions.

Referring to FIG. 1 , reduction gear transmission 100 includes braking member 10 and stator 20 .

The braking member 10 is cylindrical and has substantially the same axis as the axis X of the rotating shaft 200 . The braking member 10 is fixed to the rotating shaft 200 . More specifically, the braking member 10 is fixed to the rotating shaft 200 via the support member 90 . Therefore, the braking member 10 rotates around the axis X together with the rotating shaft 200 .

The braking member 10 is made of, for example, a ferromagnetic material such as carbon steel or cast iron. The inner peripheral surface of the braking member 10 may be coated with a highly conductive copper plating layer. A plurality of radiation fins 11 are provided on the outer peripheral surface of the braking member 10 .

The stator 20 is fixed to a non-rotating portion 300 of the vehicle, such as a transmission cover, so as not to rotate together with the rotating shaft 200 . Stator 20 includes stator case 21 , magnet holding member 22 , permanent magnet arrays 23 and 24 , and pole piece member 25 .

The stator case 21 is arranged radially inside the braking member 10 . Stator case 21 includes a case body 211 and a body holding member 212 . The case main body 211 is formed in a substantially annular plate shape centering on the axis X. As shown in FIG. The case main body 211 is fixed to the main body holding member 212 . Body holding member 212 includes a side portion 212a facing case body 211 and a bottom portion 212b projecting from side portion 212a toward case body 211 . The bottom portion 212b is attached to the non-rotating portion 300 of the vehicle via a support portion 212c. A housing space S is formed inside the stator 20 by the case main body 211 and the side portion 212 a and the bottom portion 212 b of the main body holding member 212 . The accommodation space S has a substantially annular shape centered on the axis X, and is open on the outer peripheral side.

The magnet holding member 22 is cylindrical and has the same axis X as the braking member 10 . That is, the magnet holding member 22 is arranged substantially coaxially with the braking member 10 . In the example of this embodiment, the magnet holding member 22 is arranged inside the braking member 10 in the radial direction. The magnet holding member 22 is arranged inside the housing space S. As shown in FIG.

The magnet holding member 22 does not rotate together with the rotating shaft 200 . The magnet holding member 22 is attached to the stator case 21 so as to be slidable in the circumferential direction, for example, via a ring-shaped slide plate (not shown). The magnet holding member 22 is connected to a driving device (not shown) such as an air cylinder or an electric actuator by a link mechanism (not shown). When this driving device operates, the magnet holding member 22 rotates around the rotating shaft 200 and moves in the circumferential direction with respect to the stator case 21 . By rotating the magnet holding member 22 around the rotating shaft 200, the braking state and the non-braking state of the reduction gear transmission 100 are switched. The magnet holding member 22 is made of, for example, a ferromagnetic material such as carbon steel or cast iron.

The permanent magnet arrays 23 and 24 are housed in the housing space S. The permanent magnet row 23 is arranged on the outer peripheral surface of the magnet holding member 22 . The permanent magnet array 24 is arranged in the housing space S on the outer peripheral side of the permanent magnet array 23 . The permanent magnet array 24 is attached to the stator case 21 by fixing members (not shown) such as pins and bolts. Specifically, of the axial ends of the permanent magnet array 24 , one end is fixed to the case main body 211 , and the other end is fixed to the side portion 212 a of the main body holding member 212 .

The pole piece member 25 is wound around the stator case 21 from the outer peripheral side of the permanent magnet rows 23 and 24 . The pole piece members 25 are fixed to the stator case 21 by fixing members (not shown) such as pins and bolts.

The configuration of the reduction gear transmission 100 will be described in further detail with reference to FIG. FIG. 2 is a partial cross-sectional view of the reduction gear transmission 100. As shown in FIG. A cross section is a cross section taken along a plane perpendicular to the axis X ( FIG. 1 ) of the rotating shaft 200 . In FIG. 2, the stator case 21 is omitted.

Referring to FIG. 2 , permanent magnet array 23 is composed of a plurality of permanent magnets 231 . The permanent magnets 231 are, for example, neodymium magnets, ferrite magnets, samarium-cobalt magnets, or the like. The permanent magnets 231 are arranged in the circumferential direction on the outer peripheral surface of the magnet holding member 22 . The permanent magnets 231 are arranged at predetermined intervals over the entire circumference of the magnet holding member 22 . Each permanent magnet 231 is attached to the outer peripheral surface of the magnet holding member 22 by, for example, an adhesive or welding.

Each permanent magnet 231 has a pair of magnetic poles (N pole, S pole). The direction of the magnetic poles of each permanent magnet 231 is along the radial direction and is opposite to the direction of the magnetic poles of the permanent magnets 231 on both sides. That is, each permanent magnet 231 has an north or south pole on the radially inner side and an opposite south or north pole on the radially outer side. Each permanent magnet 231 has a substantially rectangular cross section.

The permanent magnet row 24 is composed of a plurality of permanent magnets 241 . The permanent magnets 241 are, for example, neodymium magnets, ferrite magnets, samarium-cobalt magnets, or the like. The permanent magnets 241 are arranged in the circumferential direction between the braking member 10 and the permanent magnets 231 . The permanent magnets 241 are arranged at predetermined intervals in the circumferential direction. The arrangement angle of the permanent magnets 241 around the axis X (FIG. 1) of the rotating shaft 200 is equal to the arrangement angle of the permanent magnets 231 around the axis X. Each permanent magnet 241 is arranged to straddle two permanent magnets 231 adjacent in the circumferential direction.

Each permanent magnet 241 has a pair of magnetic poles (N pole, S pole). The direction of the magnetic poles of each permanent magnet 241 is along the circumferential direction and is opposite to the direction of the magnetic poles of the permanent magnets 241 on both sides. That is, each permanent magnet 241 has an N pole or an S pole on one side in the circumferential direction, and an opposite S pole or N pole on the other side in the circumferential direction.

Each permanent magnet 241 includes a top surface 241a and a bottom surface 241b. The top surface 241a is arranged on the braking member 10 side. The bottom surface 241b is longer in the circumferential direction than the top surface 241a and is arranged on the permanent magnet 231 side. The top surface 241a and the bottom surface 241b are connected by side surfaces 241c, 241c. The corners of the side surfaces 241c, 241c and the bottom surface 241b may be ground off or rounded. Similarly, the corners of the side surfaces 241c, 241c and the top surface 241a may be ground off or rounded.

The pole piece member 25 is made of a ferromagnetic material such as carbon steel or cast iron. The pole piece member 25 includes a plurality of pole piece portions 251 and a plurality of connecting portions 252 .

The pole piece portions 251 are arranged at predetermined intervals in the circumferential direction. The arrangement angle of the pole piece portion 251 around the axis X (FIG. 1) of the rotating shaft 200 is equal to the arrangement angle of the permanent magnets 231 around the axis X. FIG. The pole piece portion 251 is arranged at a position corresponding to the permanent magnet 231 in the circumferential direction.

Each of the pole piece portions 251 is arranged between the permanent magnets 241 adjacent in the circumferential direction. Each pole piece portion 251 has a shape that fills the gap between the permanent magnets 241 adjacent in the circumferential direction. Each pole piece portion 251 contacts the side surfaces 241c of the permanent magnets 241 on both sides. The pole piece portion 251 may be fixed to the adjacent permanent magnets 241 by, for example, an adhesive, or may not be fixed.

Each of the connecting portions 252 connects the pole piece portions 251 adjacent to each other in the circumferential direction. The connecting portion 252 is a plate-like portion of the pole piece member 25 that is smaller in thickness (diameter dimension) than the pole piece portion 251 . In the example of this embodiment, the connecting portion 252 is arranged radially outside the permanent magnet array 24 . That is, the connecting portion 252 covers each permanent magnet 241 from the braking member 10 side. The connecting portion 252 may be in contact with the top surface 241a of the permanent magnet 241, or may face the top surface 241a with a gap therebetween.

[Manufacturing method of eddy current speed reducer]
A method of manufacturing the eddy current speed reducer 100 will be described below. The manufacturing method of the reduction gear transmission 100 includes a step of preparing the stator 20 and a step of mounting the stator 20 and the braking member 10 to the vehicle.

(Preparation of stator)
The stator 20 is manufactured by preparing pole piece members 25 and a stator case 21 and winding the pole piece members 25 around the stator case 21 . That is, the manufacturing method of the stator 20 includes a step of preparing the pole piece members 25 , a step of preparing the stator case 21 , and a step of winding the pole piece members 25 around the stator case 21 . 3A to 3E are schematic diagrams for explaining the method of manufacturing the stator 20. FIG.

3A and 3B, when manufacturing stator 20, first, elongated pole piece members 25 are prepared. The pole piece member 25 can be formed using a plurality of metal plates 30 as shown in FIG. 3A. The metal plate 30 is produced, for example, by punching a plate-shaped material M made of a ferromagnetic material such as carbon steel or cast iron. In FIG. 3A, portions of the material M other than the metal plate 30 are hatched.

A plurality of metal plates 30 can be obtained from one sheet of material M, as shown in FIG. 3A. These metal plates 30 have the same shape. Each metal plate 30 includes a plurality of pole piece portions 31 and connecting portions 32 corresponding to the pole piece members 25, respectively.

As shown in FIG. 3B, a long pole piece member 25 is formed by stacking a plurality of metal plates 30 . The metal plates 30 are preferably bonded to each other with an adhesive or the like. The metal plates 30 are laminated in the width direction of the pole piece member 25 . The pole piece portions 31 of these metal plates 30 form pole piece portions 251 extending in the width direction. Also, the connection portion 32 of the metal plate 30 forms a connection portion 252 that connects the pole piece portions 251 to each other. The width direction of the pole piece members 25 coincides with the axial direction of the stator case 21 (FIG. 1). The pole piece member 25 has a substantially linear shape when viewed in the width direction.

In the pole piece member 25, the plurality of pole piece portions 251 are arranged in parallel with a space therebetween. A thickness t1 of each pole piece portion 251 can be, for example, 3.0 mm to 13.0 mm. The thickness t1 is the maximum length of the pole piece member 25 in the thickness direction. The thickness direction is a direction perpendicular to the longitudinal direction and width direction of the elongated pole piece member 25 . A thickness t2 of the connecting portion 252 can be, for example, 0.3 mm to 2.0 mm.

Holes 251 a are provided in at least some of the pole piece portions 251 included in the pole piece member 25 . After laminating the metal plates 30, the holes 251a are formed in the pole piece portion 251 from both sides in the width direction.

Referring to FIG. 3C, next, stator case 21 is prepared. More specifically, the case main body 211 and the main body holding member 212 before being fixed to each other are prepared. For example, one axial end of the permanent magnet array 24 is attached to the case body 211 . For example, the magnet holding member 22 holding the permanent magnet row 23 is attached to the body holding member 212 . A step 211a is provided on the surface of the case main body 211 on the accommodation space S (FIG. 1) side. A step 212d corresponding to the step 211a can also be provided on the surface of the side portion 212a of the main body holding member 212 on the housing space S side.

Referring to FIG. 3D, pole piece members 25 are wound around the prepared stator case 21 along the circumferential direction. In the example of this embodiment, the pole piece member 25 is wound around the case body 211 . The pole piece member 25 is wound around the case body 211 along the step 211a, for example. The pole piece member 25 is wound around the entire circumference of the case body 211 . The pole piece member 25 may be continuous over the entire circumference of the case body 211, or may be divided into a plurality of parts in the circumferential direction.

The pole piece member 25 is fixed to the case body 211 . More specifically, while winding the pole piece member 25 around the case body 211, a pin, bolt, or the like is inserted into the hole 251a (FIG. 3B) of the pole piece portion 251 through the through hole (not shown) of the case body 211. Thus, the pole piece member 25 is fixed to the case main body 211 . After the winding of the pole piece member 25 is completed, the main body holding member 212 is fixed to the case main body 211 with bolts or the like, as shown in FIG. 3E. After that, the permanent magnet array 24 and the pole piece member 25 fixed to the case main body 211 are also fixed to the main body holding member 212 with pins, bolts, or the like. Thereby, the stator 20 is completed.

(Mounting of stator and braking member)
By attaching the manufactured stator 20 to the non-rotating portion 300 of the vehicle and attaching the braking member 10 to the rotating shaft 200 of the vehicle, the reduction gear 100 shown in FIG. 1 is completed. In the example of this embodiment, the braking member 10 is arranged outside the stator 20 in the radial direction.

[effect]
In this embodiment, the pole piece member 25 is wound around the stator case 21 in order to provide the pole piece portion 251 in the stator 20 . Since the pole piece member 25 is elongated, the thickness t1 of the pole piece portion 251 can be directly controlled. The thickness t1 of the pole piece portion 251 is, for example, 3.0 mm to 13.0 mm, and the manufacturing tolerance is only about ±0.005 mm to 0.05 mm. Therefore, the pole piece portion 251 with high dimensional accuracy can be realized.

According to the manufacturing method of the present embodiment, the stator 20 having the pole piece portions 251 with high dimensional accuracy can be manufactured. By manufacturing the eddy current speed reducer 100 using this stator 20 , it is possible to suppress errors in the performance of the speed reducer 100 due to dimensional errors in the pole piece portions 251 . Therefore, the target performance of the reduction gear transmission 100 can be obtained more reliably.

In the present embodiment, the connecting portion 252 of the pole piece member 25 connects the pole piece portions 251 to each other on the opening side (peripheral side) of the accommodation space S of the stator 20 . As a result, the permanent magnet rows 23 and 24 in the housing space S are covered with the pole piece member 25 from the braking member 10 side. Therefore, rainwater, muddy water, or other foreign matter cannot enter the housing space S, and they do not come into contact with the permanent magnets 231 and 241 forming the permanent magnet rows 23 and 24, respectively. Therefore, rusting of the permanent magnets 231 and 241 can be suppressed, and deterioration of the performance of the reduction gear transmission 100 caused by rusting can be prevented.

In this embodiment, the pole piece member 25 is formed by laminating a plurality of metal plates 30 in its width direction. When stacking the metal plates 30 in the width direction, all the metal plates 30 can have the same shape. Therefore, the pole piece member 25 can be manufactured easily.

When the reduction gear transmission 100 is in a braking state, the braking member 10 generates eddy currents on its surface by the magnetic fluxes from the permanent magnets 231 and 241, and accordingly heats up. In contrast, in this embodiment, the braking member 10 is arranged outside the stator 20 . As a result, the braking member 10 is more likely to be exposed to the airflow, and the temperature of the braking member 10 can be suppressed. Therefore, the temperature rise of each component of the stator 20 can also be suppressed.

<Second embodiment>
FIG. 4 is a partial cross-sectional view showing a schematic configuration of an eddy current speed reducer 100A and a stator 20A in the second embodiment. The speed reducer 100A and the stator 20A differ from the speed reducer 100 and the stator 20 of the first embodiment in the configuration of the pole piece members 25A.

Referring to FIG. 4, connecting portion 252A of pole piece member 25A is arranged between permanent magnet rows 23 and 24 . That is, the connecting portion 252A is arranged inside the permanent magnet array 24 in the radial direction. The connecting portion 252A is in contact with the bottom surface 241b of each permanent magnet 241 forming the permanent magnet row 24, and holds the permanent magnet 241 together with the pole piece portion 251. As shown in FIG.

It is preferable that the connecting portion 252A is in close contact with the permanent magnet 241 so that no gap is formed between the connecting portion 252A and the bottom surface 241b of the permanent magnet 241. As shown in FIG. The bottom surface 241b of each permanent magnet 241 can be fixed to the connecting portion 252A by, for example, an adhesive. However, the bottom surface 241b of each permanent magnet 241 does not have to be fixed to the connecting portion 252A.

The reduction gear 100A and stator 20A of the present embodiment can be manufactured in the same manner as the reduction gear 100 and stator 20 of the first embodiment. That is, first, the stator 20A is manufactured using the pole piece member 25A, and then the reduction gear transmission 100A can be manufactured using this stator 20A.

5A to 5C are schematic diagrams for explaining the method of manufacturing the stator 20A. As shown in FIG. 5A, when manufacturing the stator 20A, an elongated pole piece member 25A is prepared. The pole piece member 25A is formed by laminating a plurality of metal plates 30A in the width direction. Each metal plate 30A includes a plurality of pole piece portions 31 and connecting portions 32A corresponding to the pole piece portions 251 and connecting portions 252A of the pole piece member 25A. The metal plates 30A have the same shape as each other. The metal plates 30A are preferably bonded to each other with an adhesive or the like.

Referring to FIG. 5B, prepared pole piece member 25A is wound around stator case 21 along the circumferential direction. The pole piece member 25A is wound around the case body 211 as in the first embodiment. However, in this embodiment, unlike the first embodiment, the permanent magnet array 24 is not attached to the case body 211 at this point.

Referring to FIG. 5C, after winding pole piece member 25A around case main body 211, permanent magnet array 24 is attached to case main body 211. Referring to FIG. Each permanent magnet 241 is inserted, for example, between the adjacent pole piece portions 251 along the connecting portion 252A. Each permanent magnet 241 is easily positioned by the pole piece portion 251 and the connecting portion 252A. After that, the case main body 211 and the main body holding member 212 are fixed with bolts or the like. Each permanent magnet 241 may be fixed to the case main body 211 and the main body holding member 212 with a pin, bolt, or the like, as in the first embodiment. However, each permanent magnet 241 is held by a pole piece portion 251 and a connecting portion 252A. Therefore, each permanent magnet 241 does not have to be fixed to the case main body 211 and the main body holding member 212 .

Also in the present embodiment, the elongated pole piece member 25A is used in order to provide the pole piece portion 251 on the stator 20A. Therefore, as in the first embodiment, the thickness t1 of the pole piece portion 251 can be directly controlled, and the pole piece portion 251 with high dimensional accuracy can be realized.

In this embodiment, the connecting portion 252A of the pole piece member 25A connects the pole piece portions 251 on the opposite side (inner peripheral side) to the opening of the accommodation space S of the stator 20A. Thereby, each permanent magnet 241 can be held by the pole piece portion 251 and the connecting portion 252A. Therefore, it is not necessary to directly fix each permanent magnet 241 to the stator case 21 . If each permanent magnet 241 is not directly fixed to the stator case 21, the force in the radial direction is applied to each permanent magnet 241 by the attractive force or repulsive force from the permanent magnet 231 or the repulsive force between the permanent magnets 241. When the permanent magnet 241 is subjected to a circumferential force and a rotating force (rotational moment) in response to a change in the relative positions of the permanent magnets 231 and 241 when switching between states, the permanent magnet 241 Allows movement on the spot. Therefore, the stress generated in the permanent magnets 241 can be reduced, and cracks in the permanent magnets 241 can be suppressed.

<Third Embodiment>
FIG. 6 is a schematic diagram for explaining a method of manufacturing a stator for an eddy current speed reducer according to the third embodiment. The third embodiment differs from the above embodiments in the configuration of the pole piece member 25B.

Referring to FIG. 6, pole piece member 25B is formed substantially linearly when viewed in the width direction, like pole piece members 25 and 25A of the above embodiments. The pole piece member 25B includes connecting portions 252, 252A. That is, the pole piece member 25B is provided with both a connecting portion 252 that connects the pole piece portions 251 on the radially outer side and a connecting portion 252A that connects the pole piece portions 251 on the radially inner side. there is

In the pole piece member 25B, the length of the outer peripheral side is substantially equal to the length of the inner peripheral side. However, a notch 252a is provided in each of the connecting portions 252 on the outer peripheral side of the pole piece member 25B. Thereby, the pole piece member 25B can be bent along the circumferential direction. That is, when the pole piece member 25B is bent in the circumferential direction, the notch 252a widens and the connecting portion 252 on the outer peripheral side extends, so that the pole piece member 25B can be wound around the stator case 21 along the circumferential direction.

In this embodiment, as in the second embodiment, after the pole piece member 25B is wound around the case body 211, the permanent magnets 241 are inserted between the pole piece portions 251 adjacent in the circumferential direction (FIG. 5C). After that, the case main body 211 is fixed to the main body holding member 212 .

<Fourth Embodiment>
FIG. 7 is a partial cross-sectional view showing a schematic configuration of an eddy current speed reducer 100C according to the fourth embodiment.

In each of the embodiments described above, the pole piece members 25, 25A, and 25B are formed of the metal plates 30 laminated in the width direction. On the other hand, as shown in FIG. 7, the pole piece member 25C in this embodiment is formed of metal plates 40 laminated in the thickness direction. The thickness direction of the pole piece member 25C coincides with the radial direction of the speed reducer 100C. The metal plates 40 have shapes different from each other.

A gap between the metal plates 40 overlapping in the radial direction of the reduction gear transmission 100C functions as a heat insulating layer. That is, the heat of the braking member 10 is less likely to be transmitted to the permanent magnets 231 and 241 due to the minute gaps between the metal plates 40 . Therefore, it is possible to suppress the temperature rise of the permanent magnets 231 and 241 when the reduction gear transmission 100C is used.

The pole piece member 25C includes connecting portions 252 and 252A, like the pole piece member 25B in the third embodiment. However, the pole piece member 25C may have only one of the connecting portions 252, 252A like the pole piece member 25 of the first embodiment or the pole piece member 25A of the second embodiment.

Although the embodiments according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present disclosure.

For example, in the above embodiment, the pole piece members 25, 25A, 25B, and 25C are wound around the case main body 211 of the stator case 21. As shown in FIG. However, the pole piece members 25 , 25 A, 25 B, and 25 C may be wound around the body holding member 212 of the stator case 21 . In the case of the pole piece member 25 having the connecting portion 252 only on the outer peripheral side, the case body 211 and the body holding member 212 can be fixed to each other and then wound around the stator case 21 .

In the first embodiment, the permanent magnet row 24 is attached to the case body 211 before the pole piece member 25 is wound thereon. On the other hand, in the second and third embodiments, the permanent magnet array 24 is attached to the case main body 211 after the pole piece members 25A and 25B are wound. However, the timing of attaching the permanent magnet array 24 to the stator case 21 can be changed as appropriate. Similarly, the timing of attaching the magnet holding member 22 and the permanent magnet row 23 to the stator case 21 can also be changed as appropriate.

In the above embodiments, the pole piece members 25, 25A, 25B, 25C are formed by the laminated metal plates 30, 30A or the metal plate 40. As shown in FIG. However, for example, as shown in FIGS. 8 and 9, the pole piece member can also be manufactured by forming the pole piece portion 251 by forging or the like and joining it to the support plate 50 by welding or adhesive. The pole piece portion 251 is made of a ferromagnetic material as in the above embodiment. The support plate 50 may be made of the same material as the pole piece portion 251 or may be made of a material different from that of the pole piece portion 251 . For example, only the support plate 50 can be made of a non-magnetic material.

By separately forming the pole piece portions 251 in this manner, the materials of the pole piece portions 251 and the other portions of the pole piece members 25, 25A, 25B, and 25C can be made different. However, from the viewpoint of strength, it is preferable that the pole piece portion 251 is formed integrally with other portions as in the above embodiment. Further, when the pole piece members 25, 25A, 25B, and 25C are formed by laminating the metal plates 30, 30A, and 40 as in the above-described embodiment, finishing such as forging is not required. Therefore, it is possible to further improve the dimensional accuracy of the pole piece members 25, 25A, 25B, and 25C.

In the above embodiment, the stators 20, 20A are arranged inside the braking member 10 in the radial direction. However, the stators 20, 20A may be arranged outside the braking member 10 as well. In this case, the housing space S for the stators 20 and 20A opens toward the inner periphery.

100, 100A, 100C: Eddy current speed reducer 10: Braking member 20, 20A: Stator 21: Stator case 23, 24: Permanent magnet row 25, 25A, 25B, 25C: Pole piece member 251: Pole piece portion 252, 252A : Connecting part 30, 30A, 40: Metal plate S: Accommodation space

Claims (6)

A method for manufacturing a stator for an eddy current speed reducer, which has an annular accommodation space inside which is open on the outer peripheral side or the inner peripheral side, and accommodates a permanent magnet array in the accommodation space, the method comprising:
preparing an elongated pole piece member including a plurality of pole piece portions arranged in parallel with a space therebetween and a connecting portion connecting the pole piece portions;
preparing a stator case for forming the accommodation space;
winding the pole piece member around the stator case along the circumferential direction of the accommodation space;
A manufacturing method comprising: The manufacturing method according to claim 1,
The manufacturing method, wherein the connection portion connects the pole piece portions to each other on an opening side of the accommodation space. The manufacturing method according to claim 1,
The manufacturing method, wherein the connection portion connects the pole piece portions on the side opposite to the opening of the accommodation space. The manufacturing method according to any one of claims 1 to 3,
The manufacturing method, wherein the pole piece member is formed of a plurality of metal plates laminated in the width direction of the pole piece member. The manufacturing method according to any one of claims 1 to 3,
The manufacturing method, wherein the pole piece member is formed of a plurality of metal plates laminated in a thickness direction of the pole piece member. A method for manufacturing an eddy current reduction gear used in a vehicle, comprising:
A step of preparing a stator manufactured by the manufacturing method according to any one of claims 1 to 5;
attaching the stator to a non-rotating portion of the vehicle, disposing a cylindrical braking member outside or inside the stator, and attaching the braking member to a rotating shaft of the vehicle;
A manufacturing method comprising:

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