JP2018207729A - Motor and method of cooling coil end of motor - Google Patents

Abstract

To reduce damage of a coil end caused by heat expansion of the coil end and properly transmit heat loss to a frame.SOLUTION: A motor which rotationally drives a spindle is provided. The motor has: a stator core; a coil attached to the stator core; and a motor frame which houses the stator core and the coil. The coil has a coil end protruding from the stator core in an axial direction. The motor further has: a heat conduction member configured to transmit heat of the coil end to the motor frame; and an elastic member which biases the heat conduction member so that the heat conduction member contacts with the coil end and the motor frame.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a motor and a method for cooling a motor coil end.

  Conventionally, a motor configured by accommodating a coil in a motor frame is known. In such a motor, heat based on electrical loss such as copper loss and iron loss generated in the coil is transmitted from the coil to the motor frame via the stator core, thereby cooling the motor.

  Of the heat loss generated in the coil, the heat loss generated at the coil end protruding from the stator core has a long distance from the coil end to the stator core, so the temperature of the coil end is stored in the stator core. It becomes higher than the coil part. As the motor becomes larger, the distance from the coil end to the stator core becomes longer, so that the temperature rise at the coil end becomes remarkable.

  In order to improve the cooling efficiency of the coil end, it is known that a heat conductor is disposed between the coil end and the frame, and the gap between the heat conductor, the coil end and the frame is filled with resin (patent) Reference 1). However, when the coil end is fixed with resin as described in Patent Document 1, friction is generated at the interface between the coil end and the resin due to the difference between the thermal expansion amount of the coil end and the thermal expansion amount of the resin during motor operation. It is likely to occur. For this reason, when the operation and stop of the motor are repeated, the coil end and the resin expand and contract, and there is a problem that the insulator of the coil is easily damaged. Further, when the coil end is fixed with resin, it is necessary to remove the resin neatly when the coil is rewinded, which requires a lot of maintenance.

JP 2002-191155 A

  The present invention has been made in view of the above problems, and one of its purposes is to appropriately transmit heat loss to the frame while reducing damage to the coil end due to thermal expansion of the coil end. .

  According to an aspect of the present invention, a motor that rotationally drives a main shaft is provided. The motor includes a stator core, a coil attached to the stator core, and a motor frame that houses the stator core and the coil. The coil has a coil end protruding in the axial direction from the stator core. The motor further includes a heat conducting member configured to transfer heat of the coil end to the motor frame, and the heat conducting member such that the heat conducting member contacts the coil end and the motor frame. And an elastic member for biasing.

  According to another aspect of the invention, a method for cooling a coil end of a motor is provided. The method includes a step of disposing a heat conducting member for conducting heat of the coil end to the motor frame of the motor between the coil end and the motor frame; and the coil end and the motor frame of the motor. And urging the heat conducting member so as to come into contact with.

It is a schematic sectional drawing explaining the basic composition of a motor. It is an expanded sectional view of the coil end of a motor. It is an expanded sectional view of the motor which shows the state which inserted the push bolt in the hole.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings described below, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted. FIG. 1 is a schematic cross-sectional view illustrating the basic configuration of a motor. In FIG. 1, a canned motor will be described as an example of the motor 10. As shown in FIG. 1, the motor 10 includes a main shaft 12, a motor frame 14, a stator coil 16, a stator core 18, a frame end plate 20, a rotor 22, and a can 24. The main shaft 12 is connected to a main shaft of a rotary machine such as a pump, and is configured to rotate the main shaft of the rotary machine. A rotor 22 is fitted to the outer periphery of the main shaft 12. The rotor 22 is a so-called rotor, and a rotational force is applied by an electrical interaction with the stator core 18 and the stator coil 16 (corresponding to an example of a coil), thereby rotating the main shaft 12. The stator core 18 and the stator coil 16 are disposed in the stator chamber of the motor frame 14. The stator chamber is a space defined by the motor frame 14, the frame end plate 20, and the can 24. This space is sealed, so that the fluid to be processed filled in the rotor chamber is prevented from entering the stator chamber. In the present embodiment, the motor frame 14 and the frame end plate 20 may be integrated members or separate members.

  The stator core 18 has a plurality of slots in the axial direction. The stator coil 16 is wound around the stator core 18 so as to extend in one slot of the stator core 18 and to change its direction to extend in another slot. Thereby, the coil end 17 is formed on the axially outer side of the stator core 18. As a method of winding the stator coil 16 around the stator core 18, there are known a concentrated winding in which a coil is wound around each of a plurality of teeth forming a slot and a distributed winding in which a coil is wound across a plurality of teeth. Distributed winding is further classified into concentric winding, lap winding and the like. A concentric winding coil using enameled wire is generally used for a small motor, and a lap winding coil in which an enameled wire or a copper strip having a rectangular cross section is installed in a slot is used for a medium or large motor. As the stator coil 16 of the motor 10 shown in FIG. 1, a lap winding coil can be adopted as an example.

  As shown in FIG. 1, the motor frame 14 can have cooling fins 26 on the outer peripheral surface thereof. The motor frame 14 can also have a heat exchanger 34 for cooling the motor frame 14 by passing a cooling fluid therethrough. In this case, the motor frame 14 has a cooling medium inlet 34a and a cooling medium outlet 34b. The main shaft 12 is rotatably supported by radial bearings 28 and 30 and a thrust bearing 32.

  Next, a specific cooling mechanism for the coil end 17 of the motor 10 according to the present embodiment will be described. FIG. 2 is an enlarged cross-sectional view of the coil end 17 of the motor 10. 2 shows an example of the motor 10 in which the stator chamber is not sealed, unlike the motor 10 shown in FIG. As shown in FIG. 2, the coil end 17 is configured to protrude from the stator core 18 in the axial direction of the main shaft 12 (see FIG. 1). The coil end 17 has an inner portion 17a located on the main shaft 12 side and an outer portion 17b located on the motor frame 14 side. As shown in FIG. 2, the outer portion 17 b is configured to be inclined from the stator core 18 toward the radially outer side (upper side in the drawing) of the motor frame 14. In other words, the coil end 17 is formed such that the distance between the outer portion 17b of the coil end 17 and the motor frame 14 decreases as the distance from the stator core 18 increases.

  In the present embodiment, the heat loss of the coil end 17 is transmitted to the motor frame 14 or the frame end plate 20 to cool the coil end 17, so that the motor 10 has a heat conducting ring 38 (corresponding to an example of a heat conducting member). Is provided. The heat conducting ring 38 may be formed from a ceramic material having good thermal conductivity and high insulation, such as aluminum nitride. The heat conducting ring 38 may be formed from other ceramic materials such as aluminum oxide, beryllium oxide, magnesium oxide, titanium dioxide, silicon dioxide, trisilicon tetranitride, boron nitride, and the like.

  As shown in FIG. 2, the heat conducting ring 38 is disposed between the coil end 17 and the motor frame 14. The heat conducting ring 38 has a first surface 38 a that contacts the outer portion 17 b of the coil end 17, and a second surface 38 b that contacts the inner surface of the motor frame 14. The first surface 38 a is formed in a tapered shape so as to follow the outer portion 17 b of the coil end 17. In other words, the thickness of the heat conducting ring 38 in the radial direction is formed so as to decrease as the distance from the stator core 18 increases. Thereby, the contact area of the coil end 17 and the heat conductive ring 38 can be increased, and the amount of heat transfer between the coil end 17 and the heat conductive ring 38 can be increased.

  As shown in FIG. 2, the second surface 38 b has a shape corresponding to the shape of the inner surface of the motor frame 14. The outer diameter of the heat conducting ring 38 formed by the second surface 38b is slightly smaller than the inner diameter of the motor frame 14 to such an extent that the heat conducting ring 38 can slide in the motor frame 14 in the axial direction. As a result, the contact area between the heat conducting ring 38 and the motor frame 14 can be increased, and the amount of heat transfer between the heat conducting ring 38 and the motor frame 14 can be increased. The motor frame 14 is generally cylindrical and has a curved inner surface. Therefore, in the present embodiment, the second surface 38b of the heat conducting ring 38 is formed to be curved. However, for example, when the inner surface of the motor frame 14 is flat, the second surface 38b can also be formed flat.

  Non-solidified grease, silicon sealant, or the like can be applied to the first surface 38a and the second surface 38b of the heat conducting ring 38. Thereby, the clearance gap between the 1st surface 38a and the outer side part 17b of the coil end 17 and the minute clearance gap between the 2nd surface 38b and the inner surface of the motor frame 14 can be filled, and thermal conductivity can be improved. .

  In the present embodiment, the motor 10 includes a spring 36 (corresponding to an example of an elastic member) that biases the heat conducting ring 38 so that the heat conducting ring 38 properly contacts the coil end 17 and the motor frame 14. . The spring 36 has a first end 36 a attached to the axial end of the stator core 18 and a second end 36 b attached to the heat conducting ring 38. In the present embodiment, as shown in FIG. 2, the second end portion 36 b of the spring 36 is fitted and fixed in a recess 38 c formed in the heat conducting ring 38. A plurality of springs 36 may be provided along the circumferential direction of the heat conducting ring 38. A single spring 36 may be provided. In this case, a single coil spring having substantially the same diameter as the stator core 18 can be disposed between the heat conducting ring 38 and the stator core 18.

The spring 36 biases the heat conducting ring 38 in the direction away from the stator core 18 along the axial direction (left direction in FIG. 2). As described above, the distance between the outer portion 17b of the coil end 17 and the motor frame 14 decreases as the distance from the stator core 18 increases, and the radial thickness of the heat conducting ring 38 increases. It is formed so as to decrease as it moves away from 18. Therefore, the heat conducting ring 38 is pushed by the spring 36 into the gradually narrowing gap between the outer portion 17b of the coil end 17 and the motor frame 14 with a constant pressure. As described above, the coil end 17 of the motor 10 expands due to heat generated during operation. At this time, the heat conducting ring 38 is moved in the axial direction by the spring 36 so as to follow the thermal expansion of the coil end 17. Further, when the operation of the motor 10 is stopped, the coil end 17 contracts. At this time, the heat conducting ring 38 moves in the axial direction by the frictional force at the interface between the coil end 17 and the heat conducting ring 38 as the coil end 17 contracts. As described above, since the heat conducting ring 38 can be moved in the axial direction by the spring 36, even if the coil end 17 expands or contracts, friction on the contact surface between the heat conducting ring 38 and the outer portion 17b of the coil end 17 occurs. Can be made difficult to occur. As a result, the life of the stator coil 16 can be extended.

  In the present embodiment, a coil spring is employed as the spring 36 for urging the heat conducting ring 38, but the present invention is not limited to this, and an arbitrary elastic member can be employed. For example, the elastic member may be an arbitrary spring such as a leaf spring or a disc spring, or an elastic material such as resin. From the viewpoint of reducing the replacement frequency of the spring 36, the spring 36 is preferably formed of metal or ceramics.

  In this embodiment, the first end 36 a of the spring 36 is fixed to the stator core 18, but the spring 36 is urged so as to contact the coil end 17 and the motor frame 14. If possible, the position of the spring 36 is not limited to this. For example, the spring 36 may be disposed between the frame end plate 20 and the heat conducting ring 38. In this case, the first end 36 a of the spring 36 is fixed to the frame end plate 20, and the second end 36 b is fixed to the heat conducting ring 38. By adjusting the length of the spring 36, the spring 36 can pull the heat conducting ring 38 toward the frame end plate 20.

  The motor 10 further includes a coil support ring 40 that contacts the inner portion 17a of the coil end 17. When the heat conducting ring 38 is urged by the spring 36, a force is applied from the first surface 38a of the heat conducting ring 38 to the coil end 17 so that the coil end 17 moves toward the main shaft 12 side (in the radial direction). Join. At this time, if the coil end 17 is deformed toward the main shaft 12 side, a gap is generated between the heat conducting ring 38 and the coil end 17 and heat conduction may not be performed properly. Therefore, the coil support ring 40 of the present embodiment restricts the movement of the coil end 17 toward the main shaft 12, so that the heat conducting ring 38 and the coil end 17 can be reliably brought into contact with each other.

  The frame end plate 20 has a hole 20 a into which a bolt is inserted when the stator coil 16 is attached to or removed from the stator core 18. FIG. 3 is an enlarged cross-sectional view of the motor 10 showing a state in which a push bolt is inserted into the hole 20a. When the stator coil 16 is attached to the stator core 18, as shown in FIG. 3, a push bolt 42 (corresponding to an example of a pressing member) is inserted into the hole 20 a and the heat conduction ring 38 is attached to the stator core 18. Press in the direction of approach. In this state, the stator coil 16 is attached to the stator core 18 and an insulating tape is wound around the coil support ring 40 or the like to fix the position of the coil end 17. Thereafter, when the push bolt 42 is removed from the hole 20 a, the heat conducting ring 38 is urged by the spring 36 and moves toward the frame end plate 20, and contacts the outer portion 17 b of the coil end 17. Similarly, when removing the stator coil 16 from the stator core 18, the heat conduction ring 38 is pressed in the direction approaching the stator core 18 using the push bolt 42. In this state, the stator coil 16 may be removed from the stator core 18. In addition, not only the push bolt 42 but the arbitrary pressing member which can press a heat conductive member toward a stator core can be inserted in the hole 20a.

As mentioned above, although embodiment of this invention was described, embodiment of the invention mentioned above is for making an understanding of this invention easy, and does not limit this invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof. In addition, any combination or omission of each component described in the claims and the specification is possible within a range where at least a part of the above-described problems can be solved or a range where at least a part of the effect can be achieved. is there. For example, in the present embodiment, the heat conducting ring 38 is employed as the heat conducting member, but the present invention is not limited to a ring-shaped heat conducting member. For example, the heat conducting ring 38 may be divided into a plurality in the circumferential direction. In other words, a plurality of bowl-shaped heat conduction members can be provided along the circumferential direction of the motor frame 14.

Some of the forms disclosed in this specification will be described below.
According to the 1st form, the motor which rotates a main shaft is provided. The motor includes a stator core, a coil attached to the stator core, and a motor frame that houses the stator core and the coil. The coil has a coil end protruding in the axial direction from the stator core. The motor further includes a heat conducting member configured to transfer heat of the coil end to the motor frame, and the heat conducting member such that the heat conducting member contacts the coil end and the motor frame. One or more elastic members for biasing.

  According to a second aspect, in the motor according to the first aspect, the coil end includes an inner part located on the main shaft side and an outer part located on the motor frame side, and the outer side of the coil end. The portion is configured to incline from the stator core toward the radially outer side of the motor frame, and the heat conducting member includes a first surface that contacts an outer portion of the coil end, and an inner surface of the motor frame. A first surface that is in contact with the outer surface of the coil end.

  According to the third mode, in the motor of the second mode, the second surface of the heat conducting member has a shape corresponding to the shape of the inner surface of the motor frame.

  According to the 4th form, in the motor of the 2nd or 3rd form, it has a supporting member which contacts the inside part of the coil end, and restricts movement of the coil end to the principal axis side.

  According to a fifth aspect, in the motor of any one of the first to fourth aspects, the elastic member is a spring, and the spring is a first end portion attached to an axial end portion of the stator core. And a second end attached to the heat conducting member, and urges the heat conducting member in a direction away from the stator core along the axial direction.

  According to the sixth aspect, in the motor according to the fifth aspect, the frame end plate is attached to the axial end portion of the motor frame, and the frame end plate is configured such that the heat conducting member is separated from the coil end. A hole for inserting a pressing member for pressing the heat conducting member in a direction approaching the stator core.

  According to a seventh aspect, in the motor according to any one of the first to sixth aspects, the heat conducting member is made of ceramic.

  According to the 8th form, the method of cooling the coil end of a motor is provided. The method includes a step of disposing a heat conducting member for conducting heat of the coil end to the motor frame of the motor between the coil end and the motor frame; and the coil end and the motor frame of the motor. And urging the heat conducting member so as to come into contact with.

According to a ninth form, in the method of the eighth form, the coil end has an inner part located on the spindle side of the motor and an outer part located on the motor frame side, The outer portion is configured to incline from the stator core of the motor toward the radially outer side of the motor frame, and the urging step is performed from the stator core along the axial direction of the main shaft of the motor. A step of urging the heat conducting member in the direction of separating.

  According to the 10th form, in the method of the 8th or 9th form, it has the process of restrict | limiting the movement of the said coil end to the said spindle side.

DESCRIPTION OF SYMBOLS 10 ... Motor 12 ... Main shaft 14 ... Motor frame 16 ... Stator coil 17 ... Coil end 18 ... Stator core 20 ... Frame end plate 36 ... Spring 38 ... Heat conduction ring 40 ... Coil support ring 42 ... Push bolt 17a ... Inside part 17b ... outer side 20a ... hole 36a ... first end 36b ... second end 38a ... first surface 38b ... second surface 38c ... recess

Claims (10)

A motor for rotating the spindle,
A stator core,
A coil attached to the stator core;
A motor frame that houses the stator core and the coil, and
The coil has a coil end protruding in an axial direction from the stator core,
The motor is further configured to transfer heat of the coil end to the motor frame; and
One or more elastic members that urge the heat conducting member so that the heat conducting member contacts the coil end and the motor frame. The motor according to claim 1,
The coil end has an inner part located on the main shaft side and an outer part located on the motor frame side,
The outer portion of the coil end is configured to be inclined from the stator core toward the radially outer side of the motor frame,
The heat conducting member has a first surface that contacts an outer portion of the coil end, and a second surface that contacts an inner surface of the motor frame,
The first surface is a motor that is formed in a taper shape along the outer side of the coil end. The motor according to claim 2,
The motor, wherein the second surface of the heat conducting member has a shape corresponding to the shape of the inner surface of the motor frame. In the motor according to claim 2 or 3,
A motor having a support member that contacts the inner portion of the coil end and restricts the movement of the coil end toward the main shaft. In the motor according to any one of claims 1 to 4,
The elastic member is a spring;
The spring has a first end attached to the axial end of the stator core and a second end attached to the heat conducting member, and the heat conducting member is axially A motor that urges along a direction away from the stator core. The motor according to claim 5, wherein
A frame end plate attached to the axial end of the motor frame;
The frame end plate has a hole for inserting a pressing member for pressing the heat conducting member in a direction approaching the stator core so that the heat conducting member is separated from the coil end. The motor according to any one of claims 1 to 6,
The heat conduction member is a motor formed of ceramic. A method for cooling a coil end of a motor,
Disposing a heat conducting member for conducting heat of the coil end to the motor frame of the motor between the coil end and the motor frame;
Urging the heat conducting member to contact the coil end and the motor frame of the motor. The method of claim 8, wherein
The coil end has an inner part located on the spindle side of the motor and an outer part located on the motor frame side,
The outer portion of the coil end is configured to incline from the stator core of the motor toward the radially outer side of the motor frame,
The step of urging includes a step of urging the heat conducting member in a direction away from the stator core along the axial direction of the main shaft of the motor. The method according to claim 8 or 9, wherein
A method comprising the step of restricting movement of the coil end toward the main shaft.

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