JP6453091B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a ventilation structure for a rotating electric machine, and more particularly to a cooling structure for an electric motor that rotates at a high speed.

  Generally, a rotating electrical machine such as an electric motor needs to cool a rotor and a stator, and a cooling structure for that purpose is provided. As a typical cooling structure, there is a system in which a cooling medium is circulated inside the electric motor for cooling. In a rotating machine having a relatively large capacity, a cooling medium is introduced from the outside in the axial direction to the inside of the gap (air gap) between the rotor and the stator, and the cooling medium is further passed in the axial direction at a predetermined interval. A structure is known in which a plurality of ventilation ducts provided in the stator are circulated from the inner diameter side to the outer diameter side. In some cases, a ventilation structure in which the flow direction of the cooling medium is reversed may be employed, but in the following, the cooling medium in the air gap is from the outside in the axial direction to the inside, and the cooling medium in the stator ventilation duct is the inner diameter. A case where the gas flows from the side to the outer diameter side will be described as an example.

  The stator core is formed by laminating steel plates in the axial direction in order to reduce electromagnetic loss. A plurality of slots extending in the axial direction are provided in the circumferential direction on the inner diameter side of the stator core, and a coil is accommodated in the slot. The stator ventilation duct is formed by radially arranging rod-like spacing pieces between the laminated steel plates.

  FIG. 6 illustrates a configuration of a typical conventional air gap and stator ventilation duct. The stator 2 is disposed on the outer periphery of the rotor 1 so as to face the outer periphery at a predetermined interval, and an air gap 3 is formed between the stator and the rotor. A stator coil 5 is inserted into the stator slot 4. In this conventional example, one spacing piece 7c, 7a is disposed on the outer diameter side of each slot and one tooth portion. In order to collect the laminated steel plates, clamping plates (not shown) are installed at both axial ends of the stator core and are tightened in the axial direction by through bolts or the like. The spacing piece 7 forms a ventilation duct of the stator and plays a role of transmitting a tightening force in the axial direction. In this embodiment, the number of spacing pieces is one for each of the slot portion and the tooth portion, but the number of spacing pieces is set so that the contact surface pressure between the laminated steel plate and the spacing piece and the stress applied to the spacing piece are appropriate. Is adjusted.

  Usually, at least one spacing piece of the teeth portion is necessary, and the tip on the inner diameter side extends to the vicinity of the tip on the inner diameter side of the tooth. If the spacing piece is not arranged at the tip of the teeth, there is a possibility that the lamination of the steel plates at the tip of the teeth will loosen and the vibration may occur due to electromagnetic force. Therefore, it is necessary to arrange a spacing piece at the tip of the tooth.

  By the way, in recent years, in order to reduce the installation area by reducing the size of the rotating electrical machine, the rotation speed has been increased. Further, in compressors and the like that require high-speed driving, direct driving without using a speed-increasing machine has been adopted by driving with a motor that rotates at high speed.

  If the speed of the rotating electrical machine is increased, it is possible to reduce the size even with the same capacity. However, since the efficiency does not change greatly, the total amount of heat generated by the loss does not change much. Therefore, the flow rate of the cooling medium required before and after the increase in speed does not change much. On the other hand, since the cross-sectional area of the flow path through which the cooling medium flows becomes small, the pressure loss increases and the air volume of the cooling medium decreases rather, and when the motor is downsized at high speed, it becomes difficult to cool the rotating electrical machine. For this reason, there is a need for a method for enhancing the cooling performance of rotating electrical machines that have been increased in speed.

  In a rotating electrical machine such as the conventional example, the flow path of the cooling medium with the largest pressure loss is the air gap and the ventilation duct of the stator. For cooling enhancement, the pressure loss in this portion is reduced to reduce the cooling medium. It is necessary to increase the flow rate.

  As a measure to reduce the air gap pressure loss, the slot depth is made larger than the coil height, and a ventilation space (hereinafter referred to as a vent space) is provided on the inner diameter side of the coil in the slot, thereby expanding the ventilation sectional area of the air gap. Non-Patent Document 1 discloses a method for increasing the flow rate of the cooling medium flowing in the air gap inward in the axial direction. According to this method, since the pressure loss of the air gap can be reduced, the flow rate of the cooling medium increases.

The place where the pressure loss is the largest in the stator ventilation duct is the ventilation duct entrance where the interval between the coils adjacent in the circumferential direction is the smallest. To reduce the pressure loss at the stator ventilation duct inlet, the circumferential width of the teeth on the inner diameter side of the spacing piece is tapered to increase the cross-sectional area of the duct inlet and flow into the stator ventilation duct. Patent Document 1 discloses a method for increasing the flow rate of the cooling medium. According to this method, since the ventilation loss at the stator duct inlet can be reduced, the flow rate of the cooling medium increases.

JP-A-8-205435

Hitachi review, VOL.55, No.8, p.805, 1973

  Since the conventional technique described in Non-Patent Document 1 can reduce the pressure loss of the air gap, the flow rate of the cooling medium increases. However, the effect is limited because the pressure loss in the stator ventilation duct downstream of the air gap remains large.

  Moreover, since the prior art described in Patent Document 1 can reduce the ventilation loss at the stator duct inlet, the flow rate of the cooling medium increases. However, as described above, the spacing piece has a function of transmitting the axial tightening force to hold the laminated steel sheet, and therefore, the spacing piece needs to be disposed also at the tip of the tooth. For this reason, the gap piece at the inlet of the stator duct cannot be completely eliminated, and the gap piece blocks a part of the stator duct inlet.

  In addition, when the methods of Non-Patent Document 1 and Patent Document 1 described above are simply combined, if the entrance area of the stator duct is to be increased, the width of the spacing piece that supports the laminated steel sheet at the tip of the teeth portion is reduced. Since the contact surface pressure between the spacing piece and the laminated steel sheet becomes too large, or the inner diameter side tip of the spacing piece is positioned on the outer diameter side, there arises a problem that the laminated steel sheet at the tip end portion of the teeth is not supported.

Therefore, an object of the present invention is to provide a ventilation structure having both a reduction in pressure loss in the air gap and a reduction in pressure loss at the inlet of the stator's ventilation duct and a function of supporting the laminated steel sheet at the tip of the tooth. Is to provide a rotating electric machine.

  In order to achieve the above object, the rotating electrical machine according to the present invention divides the spacing piece of the tooth portion, and sandwiches the ventilation duct inlet position of the stator, and divides the spacing piece by a predetermined distance in the radial direction. Arranged.

That is, a stator and a rotor disposed inside the stator via an air gap, and a plurality of slots arranged at predetermined intervals in the circumferential direction on the inner peripheral side of the stator, and the slots In a rotating electrical machine having a coil therein, the stator having an iron core in which steel plates are laminated, and spaced pieces are arranged radially between the steel plates to form a radial ventilation duct, the coil height is set to the slot depth. And a vent space is provided on the inner diameter side of the coil in the slot. In the teeth portion of the iron core, the inner end of the first spacing piece is located between adjacent coils, and the second spacing piece is adjacent. It is located between the vent spaces.

  By taking a large vent space, the air gap ventilation area is expanded and the pressure loss is reduced. Further, by positioning the inner diameter side tip of the first spacing piece between the adjacent coils, and arranging the second spacing piece between the adjacent vent spaces, the ventilation area of the ventilation duct inlet of the stator is reduced. Expands to reduce pressure loss. By reducing the pressure loss at the two locations of the air gap and the stator ventilation duct inlet, the flow rate of the cooling air passing through the stator ventilation duct via the air gap is increased, and the cooling is enhanced.

Furthermore, since the function of supporting the laminated steel sheet at the tip of the teeth is also maintained, there is no fear that the laminated steel sheet will loosen and vibrate due to electromagnetic force.

It is explanatory drawing of the 1st Example of the rotary electric machine of this invention. It is explanatory drawing of the 2nd Example of the rotary electric machine of this invention. It is explanatory drawing of the 3rd Example of the rotary electric machine of this invention. It is explanatory drawing of the 4th Example of the rotary electric machine of this invention. It is explanatory drawing of the 5th Example of the rotary electric machine of this invention. It is explanatory drawing of the conventional rotary electric machine.

  Hereinafter, examples will be described with reference to the drawings.

  A first embodiment of a rotating electrical machine according to the present invention will be described with reference to FIG.

  The electric motor according to the present embodiment includes a rotor 1 and a stator 2 installed so as to face the outer periphery of the rotor at a predetermined interval. An air gap 3 is formed between the stator and the rotor. A plurality of slots 4 are provided in the circumferential direction on the inner diameter side of the stator, and a stator coil 5 is inserted into the slots. The stator has an iron core 6 in which steel plates are laminated. Spacing pieces 7 are radially arranged between the steel plates to form a stator ventilation duct 8. By making the slot depth larger than the coil height, the vent space 8 is provided on the inner diameter side (air gap side) of the slot.

  The spacing piece of the tooth portion includes a first spacing piece 7a and a second spacing piece 7b. The inner end of the first spacing piece is installed so as to be positioned between the coils 5 adjacent in the circumferential direction. Moreover, the 2nd space | interval piece 7b is installed so that it may be located between the vent spaces 8 adjacent to the circumferential direction.

  According to the above configuration, the ventilation cross-sectional area of the air gap is substantially increased by the amount of the vent space, and the pressure loss is reduced. Further, since the gap piece does not block the inner diameter side entrance portion of the stator ventilation duct, the ventilation area is increased, and the pressure loss in this portion is also reduced. As a result, the flow rate of the cooling medium increases and the cooling performance can be improved.

In the present embodiment, the shape of the second spacing piece is a rectangle, but this is not a limitation, and it may be, for example, a circle (cylindrical pin) or a triangle.

  A second embodiment of the rotating electrical machine according to the present invention will be described with reference to FIG. The schematic configuration of this embodiment is substantially the same as that of the first embodiment.

  In this embodiment, the preferred arrangement of the first spacing piece and the second spacing piece is defined. In the ventilation duct of the stator, the interval on the inner diameter side of the coil adjacent in the circumferential direction is denoted by w. Further, the distance between the first spacing piece and the adjacent coils on both sides is a1 and a2, respectively, and the distance between the second spacing piece and the adjacent coil inner diameter side is b1 and b2, respectively. The first spacing piece is arranged so as to satisfy w <a1 + a2, and the second spacing piece is arranged so as to satisfy w <b1 + b2.

  According to such a configuration, since there is no gap piece at the inlet of the ventilation duct, the duct inlet area is not blocked by the gap piece, and the maximum possible ventilation area is obtained. In addition, the cross-sectional area of the stator ventilation duct is always larger than the maximum area that can be taken by the ventilation duct inlet defined by the interval between adjacent coils, so that a large pressure loss may occur in places other than the ventilation duct inlet. Absent.

The distances a1 and a2 between the first spacing piece and the coil can be adjusted by the circumferential width and radial position of the inner diameter side tip of the first spacing piece. Further, the distances b1 and b2 between the second spacing piece and the coil inner diameter side can be adjusted by the size of the second spacing piece and the radial position.

  A third embodiment of the rotating electrical machine according to the present invention will be described with reference to FIG. The schematic configuration of this embodiment is substantially the same as that of the first embodiment.

  In the present embodiment, the tip on the inner diameter side of the first spacing piece 7a is tapered so that the circumferential width decreases toward the inner diameter side.

According to such a structure, the ventilation cross-sectional area of the inner diameter side tip can be made larger. Or, even if it extends to the inner diameter side, it can have the same opening area as the rectangular spacing piece, so the axial tightening load can be dispersed, and the contact surface pressure between the spacing piece and the steel plate becomes more uniform it can.

  A fourth embodiment of the rotating electrical machine according to the present invention will be described with reference to FIG. The schematic configuration of this embodiment is substantially the same as that of the first embodiment.

In this embodiment, an example is shown in which a plurality of first spacing pieces are arranged on one tooth. Since it is necessary to adjust the contact area between the spacing piece and the laminated steel sheet according to the tightening load in the axial direction, when a large contact area is required, the configuration of this embodiment can be adopted. The plurality of first spacing pieces may have the same length, but by arranging spacing pieces having different lengths as in this embodiment, the change in the cross-sectional area in the stator ventilation duct can be reduced. As a result, the pressure loss is also reduced.

  A fifth embodiment of the rotating electrical machine according to the present invention will be described with reference to FIG. The schematic configuration of this embodiment is substantially the same as that of the first embodiment.

In this embodiment, an example in which a plurality of second spacing pieces are arranged is shown. If the vent space 8 is widened in order to increase the ventilation cross-sectional area of the air gap, the region of the teeth sandwiched between the vent spaces adjacent in the circumferential direction is also widened. The axial tightening load applied to the tip of the tooth also increases in proportion to the area of the tooth region. Thus, when vent space is enlarged, it is necessary to enlarge the contact area of a 2nd space | interval piece and a laminated steel plate. The present embodiment is a suitable arrangement of spacing pieces in such a case.

1 Rotor 2 Stator 3 Air gap 4 Slot 5 Stator coil 6 Stator core 7 Spacing piece 8 Vent space

Claims (5)

A stator and a rotor disposed inside the stator via an air gap, and a plurality of slots arranged at predetermined intervals in the circumferential direction on the inner peripheral side of the stator; In the rotating electrical machine having a coil, the stator has an iron core in which steel plates are laminated, and radial pieces are arranged between the steel plates to form radial ventilation ducts.
Dividing at least a portion of the distance piece and the first distance piece arranged on the outer diameter side, to a second distance piece arranged on the inner diameter side,
Making the coil height smaller than the slot depth,
A vent space is provided on the inner diameter side of the coil in the slot,
In the teeth portion of the iron core, the inner diameter tip of the first spacing piece is located between adjacent coils, and is located on the outer diameter side of the inner diameter side end surface of the coil ,
The rotating electrical machine characterized in that the second spacing piece is located between adjacent vent spaces and is located on the inner diameter side of the inner diameter side end face of the coil .
2. The rotating electrical machine according to claim 1, wherein the distance between the first spacing piece and the coils on both sides adjacent to each other in the circumferential direction is a1 and a2, respectively, and the lower end of the coil is adjacent to the second spacing piece. The rotating electric machine is characterized in that spacing pieces are arranged so as to satisfy the relationship of w <a1 + a2 and w <b1 + b2, where b1 and b2 are the distances of each and w is the minimum spacing between the adjacent coils.
2. The rotating electrical machine according to claim 1, wherein a tip shape on an inner diameter side of the first spacing piece is tapered.
The rotating electrical machine according to claim 1, wherein a plurality of the first spacing pieces are arranged.
  The rotating electrical machine according to claim 1, wherein a plurality of the second spacing pieces are arranged.