JP2014225944A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure uniform, high heat dissipation from a coil end while maintaining high productivity.SOLUTION: A coil end cover 32 of a U-shaped cross section composed of a synthetic resin having heat conductivity and electrical insulation properties is mounted to a coil end 29a in a state where a surface of the coil end is covered and a gap c in which a filler 30 may be circulated from and to the coil end 29a is formed. By providing a filler passage 33 at an end face wall 32a and both side walls 32b, 32b and filling a filler 30 in the gap c through the filler passage 33 in a sealing step, a resin layer 33 for securing heat conductivity is formed.

Description

  The present invention relates to a so-called resin mold type electric motor in which a coil end of a stator is covered with a filler made of synthetic resin having heat conductivity and electrical insulation.

  As shown in FIG. 5, the electric motor includes a rotor 2 that rotates about the electric motor shaft 1 and a stator 3 that is disposed on the outer periphery of the rotor 2 in a box-shaped housing 4 that is open on one side in the electric motor axial direction. The end cover 5 is mounted on one side of the housing 4 which is open.

  Here, an electric motor installed in a vertical orientation in which the electric motor shaft 1 is vertical like a swing electric motor of an excavator, in which the upper surface side of the housing 4 is opened, and the end cover 5 is attached to the upper surface opening. For example.

  Hereinafter, on the premise of this, in the prior art shown in FIGS. 5 and 6 and an embodiment of the present invention described later, the motor shaft direction (the shaft direction of the motor shaft 1) will be described as the vertical direction. In addition, the upper side and the lower side of the figure are expressed as “upper” and “lower” of the electric motor as they are.

  Further, in this specification, the “motor” includes a generator and a generator motor based on the same principle as the motor.

  The end cover 5 is attached to the upper end surface of the housing 4 with bolts (not shown), and the upper portion of the motor shaft 1 is rotatably supported by the end cover 5 and the lower portion is supported by the lower portion of the housing 4 via bearings 6 and 7, respectively. The

  The stator 3 includes a stator core 8 formed by laminating electromagnetic steel plates, and a stator coil 9 wound around the stator core 8 in the vertical direction.

  The stator coil 9 is wound in a state where coil ends 9 a that are folded portions on both upper and lower sides protrude from both upper and lower end surfaces of the stator core 8.

  In the resin mold type electric motor, after the coil is wound, the stator 3 is inserted into the housing 4, and a filler (synthetic resin material such as unsaturated polyester having electrical insulation and heat conductivity) 10 is provided from the upper die. Injected and filled.

  As a result, the entire stator 3 is sealed and fixed in the housing 4 with the filler 10, and heat transfer (heat dissipation) from the stator 3 to the housing 4 and the end cover 5 is enhanced.

  The housing 4 is provided with a cooling passage 11 through which a coolant such as water passes, and the housing 4 is cooled by the cooling passage 11. The cooling passage 11 is configured as a circulation passage through which a refrigerant circulates via a tank by a pump (not shown).

  In such a resin mold type electric motor, as shown in FIG. 6, a coil end cover 12 is mounted on a coil end 9a in a state where a resin layer 13 having heat conductivity is formed between them. (See Patent Document 1).

  In this known technique, a coil-shaped thin sheet material made of copper or aluminum is placed on the coil end 9a and bent into a U-shaped cross section so as to follow the outer shape of the coil end 9a to form the coil end cover 12.

  In addition, the resin layer 13 is formed on the inner surface of the cover by applying a molten resin material with a thickness of 0.2 mm to 0.3 mm to one side of the sheet material in advance and solidifying it.

  In the known technique, a corrugated space is further provided between the coil end cover 12 and the end cover 5, but since it is not directly related to the present invention, illustration and detailed explanation are omitted here.

  As described above, by attaching the coil end cover 12 to the coil end 9a, the coil end groups on both the upper and lower sides can be prevented from being deformed or displaced due to vibration during the transportation of the stator, and the stator 3 can be placed in the housing 4. It is possible to prevent interference with the housing 4 when assembled into the housing.

Japanese Patent Laid-Open No. 10-290543

  In the case where the coil end cover 12 is mounted on the coil end 9a as described above, if an air gap (gap) is generated between the two, the heat transfer resistance is increased at this portion, so that the heat transfer performance is lowered. That is, it becomes impossible to ensure a uniform and high heat radiation action from the coil end group to the housing 4 or the end cover 5.

  Here, according to a known technique, since the resin layer 13 is formed by coating a resin material in a thin film shape on one side of the sheet material, uneven application of the resin material or the resin layer when mounted on the coil end 9a. 13 peeling is inevitable.

  In addition, since the coil end dimension varies greatly in the manufacturing process, the resin layer 13 itself can be formed to have a uniform thickness, and even if there is no peeling, the coil end dimension is particularly small in the portion where the coil end dimension is small. There is a possibility that a gap (a portion having low heat conductivity) is generated between the coil end 9a.

  Due to these points, according to the known technology, it is actually difficult to ensure uniform heat transfer by the resin layer 13, and the heat transfer is partially reduced, and the heat dissipation from the coil end 9 a to the housing 4 or the end cover 5 is reduced. There was a risk of lowering.

  In addition, as a measure for preventing the gap, the coil end dimension is strictly controlled at the coil winding stage, the accuracy of applying the resin material to the sheet material is increased, and the resin layer 13 is prevented from being peeled off at the coil end cover mounting stage. It is conceivable to take this, but this is not realistic because productivity is significantly reduced.

  Therefore, the present invention provides an electric motor capable of ensuring uniform and high heat dissipation from a coil end while maintaining high productivity.

As means for solving the above-described problems, in the present invention, a rotor that rotates about an electric motor shaft and a stator disposed on the outer periphery of the rotor are accommodated in a housing, and the stator includes a stator core and a stator coil. The stator coil is wound around the stator core with coil ends, which are folded portions on both axial sides of the motor shaft, protruding axially from both ends of the stator core, and in the sealing process, heat transfer and electrical insulation are performed. In an electric motor in which a filler made of a synthetic resin material having the properties is injected into the housing in a state of covering the coil ends, and the stator is sealed in the housing, the coils having heat conductivity at both the coil ends End cover,
(I) Cover the coil end surface,
(II) It is mounted in a state where a gap through which the filler can flow is formed between the filler passage through which the filler can flow in the sealing step and the coil end cover, and the filler is filled with the filler. The resin layer is formed by filling the gap through the material passage.

  According to this configuration, the coil end cover is covered with the filler together with the filler in the sealing step of injecting the filler, and at the same time, the filler is introduced into the coil end cover from the filler passage so that the coil end and the coil are covered. It is filled between the end covers (gap).

  In other words, as long as there is a gap for the filler to enter between the coil end and the coil end cover, a resin layer should be reliably formed between the coil end cover and the coil end cover for all coil ends. Can be prevented.

  Moreover, as long as the coil end cover dimensions are set so as to ensure a gap through which the filler can circulate, the resin layer can be reliably formed regardless of the size of some gaps (some variations in coil end dimensions). This eliminates the need for strict management of coil end dimensions and the like, and eliminates the need for a separate process for coating and forming a resin layer as in the known art. For this reason, high productivity can be maintained.

  In the present invention, it is desirable that the coil end cover is formed of a synthetic resin material having heat conductivity and electrical insulation (Claim 2).

  This eliminates the problem of electrical insulation (insulation breakdown or the like) between the coil end and the coil end cover, as in the known technique in which the coil end cover is made of metal (conductor).

  In the present invention, the coil end cover is formed in a ring shape with a U-shaped cross section composed of an end wall and both side walls, and is mounted so as to collectively cover the coil end groups on both sides of the stator in the motor axial direction. (Claims 3 and 4).

  According to this configuration, it is easy to attach the coil end cover to the coil end groups on both sides, the assemblability is good, and the effect of preventing deformation and displacement of each coil end is further enhanced.

  When this configuration is adopted, it is desirable to form the filler passage by providing a through hole in at least one of the end wall and the side wall of the coil end cover.

  In this way, by forming filler passages in the coil end cover itself, for example, compared to the case where the filler end passage is left leaving a ring-shaped gap over the entire circumference between the side wall ends of the coil end cover and the stator core. Thus, the filling material easily spreads over the entire area between the coil end and the coil end cover, and voids due to filling unevenness are less likely to occur.

  According to the present invention, uniform and high heat dissipation from the coil end can be ensured while maintaining high productivity.

It is sectional drawing of the electric motor which concerns on embodiment of this invention. It is sectional drawing which shows the step which incorporates a stator in a housing after coil winding in the same electric motor. It is a partial expanded sectional view which shows the condition which inject | pours a filler after incorporation. FIG. 4 is a view corresponding to FIG. 3 showing a second embodiment of the present invention. It is sectional drawing of the conventional common electric motor. It is a partial expanded sectional view of the well-known technique equipped with the coil end cover.

  An embodiment of the present invention will be described with reference to FIGS.

  The embodiment is applied to a resin-molded electric motor that is installed in a vertical orientation in which the electric motor shaft is vertical, such as an excavator turning electric motor, in accordance with the description of the background art.

  In the electric motor according to the embodiment, the following points are the same as the prior art shown in FIGS.

  (A) A rotor 22 that rotates about an electric motor shaft 21 and a stator 23 disposed on the outer periphery of the rotor 22 are accommodated in a box-shaped housing 24 having an upper surface opened, and an end cover 25 is disposed on the upper surface of the housing 24. The point that is configured by wearing.

  (B) The end cover 25 is attached to the upper end surface of the housing 24 with bolts (not shown), and the upper portion of the motor shaft 21 is rotatable on the end cover 25 and the lower portion is rotatable on the lower portion of the housing 24 via bearings 26 and 27, respectively. Points supported by.

  (C) The stator 23 includes a stator core 28 formed by laminating electromagnetic steel plates and a stator coil 29 wound around the stator core 28 in the vertical direction.

  (D) The stator coil 29 is wound in such a manner that coil ends 29a which are folded portions on both upper and lower sides protrude from the upper and lower end surfaces of the stator core 28 in the motor shaft direction.

  (E) In the sealing step after coil winding, the stator 23 is inserted into the housing 24, and a filler (synthetic resin material such as unsaturated polyester having electrical insulation and heat conductivity) 30 is injected from the upper mold. By filling, the entire stator 23 including the coil end group is sealed and fixed in the housing 24 with the filler 30, and heat transfer (heat dissipation) from the stator 23 to the housing 24 and the end cover 25 is improved. point.

  (F) A cooling passage 31 for cooling the housing 24 by circulating a coolant such as water is provided on the outer peripheral side portion of the housing 24.

  Also in this electric motor, the coil end cover 32 is attached to the upper and lower coil end groups so as to cover the surface of each coil end, as in the known technique shown in FIG.

  The coil end cover 32 is made of a synthetic resin having electrical insulation and heat transfer, and has a U-shaped cross section composed of an end face wall 32a and left and right side walls 32b, 32b. The coil end cover 32 has a ring shape with a certain rigidity and elasticity. It is formed as a frame and is mounted so as to cover the coil end groups on both the upper and lower sides collectively.

  Specifically, the coil end cover 32 has the ends of the side walls 32b and 32b in contact with the end surface in the motor shaft direction of the stator core 28 in the mounted state as shown in the figure, and in this state the end surface wall 32a and the side walls 32b and 32b The cross-sectional size is set so that a sufficient gap c is formed between the coil end 29a and the filler 30 to circulate in the sealing process, and the coil ends 29a are attached to both coil end groups prior to the sealing process. .

  The coil end cover 32 is provided with through holes 33 penetrating in the thickness direction at substantially the center portions of the end wall 32a and the side walls 32b, 32b at a plurality of locations in the circumferential direction (positions corresponding to the coil ends 29a). It has been.

  The through hole 33 is provided as a round hole (which may be a square hole) having a diameter sufficient to allow the filler 30 injected into the housing 24 to pass through in the sealing step.

  In other words, the filler passage is formed by the through-hole 33 in a state where the coil end cover 32 is attached to the coil end group.

  The through holes 33 may be provided at a rate of one wall per one coil end 29a, or may be provided at a rate of plural.

  FIG. 2 shows a state where the stator 23 is assembled in the housing 24 with the coil end cover 32 attached to the coil end group as the first stage of the sealing process.

  At this time, the coil end groups on both the upper and lower sides are held in a state of protruding straight from the stator core end surface in the motor shaft direction by the shape retaining action of the coil end cover 32, and thus the coil end 29a interferes with the housing 24 and may be damaged. There is no risk of being pinched between the housing 24.

  After the incorporation of the stator, the filler 30 is injected and filled into the housing 24 from an upper mold (not shown) set above the housing.

  As a result, as shown in FIG. 1, the entire stator 23 including the coil end group and the coil end cover 32 is sealed and fixed in the housing 24 with the filler 30, and is mounted from the stator 23 to the housing 24 and after the sealing process. Further, heat transfer to the end cover 25 (heat dissipation) is improved.

  FIG. 3 shows a filling state of the filler 30 in the sealing process. The filler 30 covers the coil end 29a together with the coil end cover 32, and passes through the through-hole 33 as shown by an arrow in the drawing, so that the coil end cover 32 is covered. Into the gap c between the coil end 29a and the coil end cover 32.

  That is, the through hole 33 becomes a filler passage, and the filler 30 is filled into the gap c through the passage.

  Thus, the gap 30 is filled with the filler 30 to form the resin layer 30 ′, and the heat from the coil end 29 a passes through the resin layer 30 ′, the coil end cover 32, the filler 30, the housing 24 or the end cover 25. Is dissipated to the outside or transmitted to and absorbed by the cooling passage 31.

  According to this configuration, the resin layer 30 ′ as a good heat transfer layer can be reliably formed between all the coil ends 29 a and the coil end cover 32. In other words, it is possible to reliably prevent the generation of voids having a large heat transfer resistance.

  For this reason, the heat dissipation from the coil end 29a to the housing 24 and the end cover 25 or the cooling passage 31 can be reliably improved.

  In addition, as long as the dimension of the coil end cover 32 is set so that the gap c through which the filler 30 can flow is ensured, the resin layer regardless of the size of the gap c (a slight variation in the coil end dimension). Since 30 ′ can be secured, strict management of coil end dimensions and the like is not necessary, and a separate process for coating and forming a resin layer as in the known technique is not necessary. For this reason, high productivity can be maintained.

  In addition, since the coil end cover 32 is formed of a synthetic resin material having heat conductivity and electrical insulation, a known technique in which the coil end cover 12 is formed of metal (conductor) as shown in FIG. The problem of electrical insulation (insulation breakdown or the like) between the coil end 9a and the coil end cover 12 is eliminated.

  Further, the coil end cover 32 is formed in a ring shape with a U-shaped cross section comprising an end face wall 32a and both side walls 32b, 32b, and is mounted so as to collectively cover the coil end groups on both the upper and lower sides of the stator 23. Therefore, the coil end cover 32 can be easily attached to the coil end groups on both sides, the assemblability is good, and the effect of preventing deformation and displacement of each coil end is further enhanced.

  In addition, since the filler passage (through hole) 33 is provided in the end face wall 32a and both side walls 32b and 32b of the coil end cover 32, that is, the coil end cover 32 itself, the filler is arranged between the coil end and the coil end cover. It becomes easy to spread evenly throughout the space, and voids due to filling unevenness are less likely to occur.

Other embodiments
(1) The filler passage (through hole) 33 may be provided only in one of the end wall 32a and the side walls 32b, 32b.

  On the other hand, as shown in FIG. 4, by setting the vertical dimension of both side walls 32b, 32b to be sufficiently shorter than the projecting dimension of the coil end 29a, the entire circumference is formed between the end of the side wall and the end face of the stator core 28. It may be formed as a ring-shaped gap extending over.

  Alternatively, a notch may be provided at the front ends of the side walls 32b and 32b, and a tunnel-like portion formed between the notch and the end face of the stator core 28 may be used as the filler passage.

  When the filler passage 33 is formed by the ring-shaped gap or the tunnel-like portion, the gap c is increased in order to reliably spread the filler 30 to the coil end end face far from the passage 33 (filler inlet). It is desirable to set to.

  (2) The coil end cover 32 may be formed of a conductive metal such as copper or aluminum. Even in this case, as shown in FIG. 6, the resin layer 30 'can be formed with a much higher probability than the known technique of applying and forming the resin layer 13, and there is a possibility that the resin layer 30' may be peeled off during the mounting as in the known technique. As a result, there is no problem of electrical insulation.

  (3) The present invention can be applied not only to the vertically arranged electric motor but also to the horizontally arranged electric motor, and also to the generator and the generator electric motor of the same principle as described above.

21 Motor shaft 22 Rotor 23 Stator 24 Housing 25 End cover 26 Bearing 28 Stator core 29 Stator coil 29a Coil end 30 Filling material 30 'Resin layer 32 Coil end cover 32a Coil end cover end wall 32b Same left and right side walls c Clearance 33 Filling Material passage

Claims (4)

A rotor that rotates about the motor shaft and a stator disposed on the outer periphery of the rotor are housed in a housing. The stator includes a stator core and a stator coil, and the stator coils are arranged on both sides in the axial direction of the motor shaft. A coil end that is a folded portion is wound around the stator core in a state of protruding in the axial direction from both ends of the stator core, and in the sealing step, a filler made of a synthetic resin material having heat conductivity and electrical insulation is provided. In the electric motor in which the stator is sealed in the housing by being injected into the housing in a state of covering the coil ends, a coil end cover having heat conductivity on the coil ends on both sides,
(I) Cover the coil end surface,
(II) It is mounted in a state where a gap through which the filler can flow is formed between the filler passage through which the filler can flow in the sealing step and the coil end cover, and the filler is filled with the filler. An electric motor comprising a resin layer formed by filling the gap through a material passage.   2. The electric motor according to claim 1, wherein the coil end cover is formed of a synthetic resin material having heat conductivity and electrical insulation.   The coil end cover is formed in a ring shape with a U-shaped cross section composed of an end face wall and both side walls, and is mounted so as to collectively cover the coil end groups on both sides of the stator in the axial direction of the motor. Item 3. The electric motor according to item 1 or 2.   4. The electric motor according to claim 3, wherein the filler passage is provided as a through hole in at least one of an end face wall and a side wall of the coil end cover.

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