Rotating Electric Machine

Abstract

To efficiently cool a rotary electric machine in the rotary electric machine.SOLUTION: The present invention relates to a rotary electric machine comprising: a stator 6; a rotor 5 which is connected to a rotary shaft 10; a housing 7 enclosing the stator and the rotor; an anti-load-side end bracket 3 connected with the housing; and a fan 1 blowing a cooling wind from the side of the anti-load-side end bracket. The anti-load-side end bracket 3 includes: a first penetration hole 100 which allows the cooling wind to pass through the inside of the housing; a first tapered part 3A including an apex between the first penetration hole and an outer periphery of the anti-load-side end bracket and tilted in a load direction from the apex to the first penetration hole; and a second tapered part 3B tilted in the load direction from the apex to the outer periphery of the anti-load-side end bracket.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a cooling structure for a rotating electrical machine. [Background technology]

[0002] In general, rotating electric machines such as electric motors and generators tend to become larger when attempting to achieve higher output and torque. As the size of the rotating electric machine increases, the mechanical device in which the rotating electric machine is incorporated also needs to become larger, which creates problems such as space restrictions for installing the device and high costs.

[0003] In rotating electric machines, heat is generated inside the rotating electric machine due to losses such as copper loss and iron loss that occur when a load is applied while the machine is in operation, and this heat is then dissipated to the housing surface by thermal conduction. By suppressing the heat generated inside the rotating electric machine, it is possible to make the machine smaller for the same output, thereby reducing costs. Furthermore, for the same size, it is possible to achieve higher output and larger torque. In permanent magnet type rotating electric machines, the temperature rise of the permanent magnets is suppressed and the resistance of the permanent magnets to permanent demagnetization is increased, allowing the permanent magnets to be made thinner, thereby further reducing costs.

[0004] Cooling fans are often used to suppress temperature rise inside rotating electrical machines. One example of a cooling structure using a cooling fan is disclosed in Patent Document 1. Patent Document 1 discloses a structure in which a cooling fan is provided at the lower center position of an end bracket on the non-load side to circulate cooling air inside the rotating electrical machine and suppress temperature rise. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-187792 A Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 discloses a technology for suppressing heat generation from a rotating electric machine by ventilating cooling air from a cooling fan into the inside of the rotating electric machine. The cooling fan is disposed on an inclined portion inside an end bracket. However, the motor body cannot be efficiently cooled because the cooling air from the cooling fan is ventilated only into the inside of the rotating electric machine, while heat generated inside the rotating electric machine is dissipated from the housing surface by thermal conduction.

[0007] An object of the present invention is to more efficiently cool a rotating electrical machine. [Means for solving the problem]

[0008] Representative examples of the "rotating electric machine" of the present invention that can achieve the above object include: a stator, a rotor connected to a rotating shaft, a housing surrounding the stator and the rotor, a non-load side end bracket connected to the housing, and a fan that blows cooling air from the non-load side end bracket side; A fan cover that covers the fan to an end of the housing on the opposite load side; Equipped with the anti-load side end bracket has a first through hole that allows cooling air to pass inside the housing, a first tapered portion that has an apex between the first through hole and an outer periphery of the anti-load side end bracket and that slopes in the load direction from the apex to the first through hole, and a second tapered portion that slopes in the load direction from the apex to the outer periphery of the anti-load side end bracket; a third tapered portion located between the rotating shaft and the first through hole and inclined in a load direction from the rotating shaft to the first through hole; It has the following characteristics. Effect of the Invention

[0009] According to the present invention, it is possible to efficiently cool a rotating electrical machine.

[0010] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an overall configuration of a motor according to a first embodiment. [Diagram 2] 2 is a cross-sectional view of the motor taken along line AA' in FIG. [Diagram 3] FIG. 4 is a surface view of the anti-load side end bracket. [Figure 4] FIG. 4 is a cross-sectional view of the anti-load side end bracket taken along the line BB' in FIG. [Diagram 5] FIG. 4 is a diagram showing the flow of cooling air in the non-load side end bracket of FIG. 3. [Figure 6] 3 is a diagram showing the flow of cooling air in the motor of FIG. 2. [Figure 7] FIG. 1 is a cross-sectional view showing a configuration of a motor using a self-excited fan. [Figure 8] FIG. 4 is a diagram showing a second embodiment in which a fin is added to the center of the end bracket on the counter-load side in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the rotating electric machine will be described with reference to the drawings. However, the present invention is not limited to the description of the embodiment shown below. Those skilled in the art will easily understand that the specific configuration can be changed without departing from the concept or gist of the present invention. In each drawing for explaining the embodiments, the same components are denoted by the same names and symbols as much as possible, and repeated explanations are omitted. EXAMPLES

[0013] A rotating electric machine according to a first embodiment of the present invention is shown in Fig. 1 and Fig. 2. Fig. 1 is a perspective view showing the overall configuration of a motor according to this embodiment, and Fig. 2 is a cross-sectional view of the motor taken along line AA' in Fig. 1.

[0014] The rotating electric machine in this embodiment includes a stator 6, a rotor 5, and a rotating shaft 10, which are housed in a space formed by a housing 7 and end brackets 3 and 8, with a fan cover 2 and a fan 1 attached to the outside. Here, the stator 6 is shrink-fitted into the housing 7, or may be press-fitted. Hereinafter, the rotating shaft will be referred to as the shaft 10.

[0015] The rotor 5 and shaft 10 are placed inside the stator 6. The shaft 10 and rotor 5 are connected by shrink fitting, and bearings 4, 9 may be further shrink fitted near both ends of the shaft. End brackets 3, 8 are placed on the load side and anti-load side of the housing. The end brackets 3, 8 function as bearing holders. A fan cover 2 is placed so as to cover from the anti-load side end bracket 3 to near the end of the housing 7, and on the outside of that is the separately excited fan 1, which is placed on the shaft.

[0016] The rotor 5 is fixed to a shaft 10, and its main components are a cylindrical rotor core made of laminated magnetic material, a backing plate disposed at the axial end of the rotor core, and a permanent magnet embedded inside the rotor core. The shaft 10, which is shrink-fitted into the rotor core, is held by end brackets 3, 8 via bearings 4, 9, and the rotor 5 is supported in the stator 6 so as to be freely rotatable.

[0017] The permanent magnets are arranged inside the rotor core with alternating magnetic poles in the circumferential direction, forming eight pole pairs in this embodiment. The permanent magnets may be made of any material, such as ferrite, neodymium, or samarium-cobalt. The permanent magnets may be divided into multiple pieces in the radial or circumferential direction.

[0018] FIG. 3 shows a surface view of the end bracket 3 on the opposite load side. FIG. 4 shows a cross-sectional view of the end bracket 3 on the opposite load side at the cross section BB' in FIG. 3. The end bracket 3 on the opposite load side is attached to the housing 7, and the outer surface of the end bracket 3 on the opposite load side is provided with a taper in two stages that forms an inclined surface so that the fan 1 side is the apex. That is, the outer surface of the end bracket 3 has a caldera structure (a cross section that is "L" shaped). Hereinafter, the first taper portion of the end bracket 3 on the opposite load side is called taper 3A, the second taper portion on the outer side of the first taper portion is called taper 3B, and the third taper portion on the inner side of the first taper portion is called taper 3C. The fins of the first taper portion are called fins 3a, and the fins of the second taper portion are called fins 3b.

[0019] Between the axis of the shaft 1 and the taper 3A of the end bracket 3, a continuous through hole 100 is provided in the circumferential direction around the axis of the shaft 1. The through hole 100 may be tapered. For example, by tapering from the anti-load side to the load side so that the hole diameter becomes smaller, the thickness of the bearing installation position of the anti-load side end bracket can be left and strength can be provided. In addition, by making the through diameter the same in the axial direction, the intake port through which the cooling air enters can be made large. This can reduce the ventilation resistance and allow the cooling air to be blown inside more efficiently. The shape of the through hole 100 can be a square hole, and is not limited to a long hole, since the cooling efficiency improves as the surface area of ​​the hole is made larger, and it does not have to be tapered. The cooling air from the fan 1 hits the outer surface of the end bracket 3 and is divided into two. One flows along the inner taper 3A and into the through hole 100, and is easy to flow inside the housing 7. The other flows along the outer taper 3B and is easy to flow to the outer periphery of the housing 7. In addition, although aluminum is used for the end brackets 3 in this embodiment, iron or stainless steel may also be used.

[0020] To summarize the shape of the anti-load side end bracket, the anti-load side end bracket 3 has a through hole 100 between the rotating shaft (shaft) 1 and the outer periphery of the end bracket which allows cooling air to pass inside the housing, and has a first tapered portion which has an apex between the through hole 100 and the outer periphery of the anti-load side end bracket and slopes in the load direction from the apex to the through hole 100, a second tapered portion which slopes in the load direction from the apex to the outer periphery of the anti-load side end bracket, and a third tapered portion which is located between the rotating shaft 1 and the through hole 100 and slopes in the load direction from the rotating shaft to the through hole 100.

[0021] Fins 3a and 3b are arranged on the outer surface of the non-load side end bracket 3 along tapers 3A and 3B of the end bracket, respectively. By arranging the fins 3a and 3b, the surface area that the cooling air from the fan 1 hits is increased, thereby increasing the cooling effect. The fins are arranged evenly in the circumferential direction around the axis. By arranging the fins 3a and 3b on tapers 3A and 3B of the end bracket 3, respectively, a flow path is formed that makes it easy for the cooling air from the fan 1 to be blown to the inside of the housing and to the outer periphery of the housing.

[0022] Next, the flow of the cooling air 20 will be described with reference to Figs. 5 and 6. Figs. 5 and 6 are diagrams in which the flow of the cooling air 20 has been added to Figs. 3 and 2. The cooling air 20 discharged from the fan 1 hits the surface of the non-load side end bracket 3 and is divided into two. One flows directly along the outer taper 3B to the upper part of the housing and is discharged to the outside as guided by the fins 3b. The other cooling air that hits the inner taper 3A flows directly along the taper 3C and flows into the through hole 100 as guided by the fins 3a. Then, it flows into the inside of the housing 7, and one part passes through the stator part 6 and the other part passes through the rotor part 5 in the axial direction. Then, each cooling air passes through the through hole 101 provided in the load side end bracket 8 and is discharged to the outside.

[0023] The cooling air 20 sent to the anti-load side end bracket 3 is a swirling air. It is preferable that the apexes of the tapers 3A and 3B of the anti-load side end bracket 3 and the apexes of the fins 3a and 3b are located outside the fan 1 when viewed from the shaft 10. The swirling air has a faster wind speed on the outer periphery side than on the inner periphery side, and the faster the wind speed, the greater the cooling effect. Therefore, the cooling air 20 can be sent to the top of the housing 7 and inside the motor while maintaining its high wind speed, improving the cooling effect.

[0024] Moreover, it is more preferable that the fins 3a and 3b are continuous and have the same width. The same is true at the branching point of the fins 3a and 3b. This is to eliminate elements (steps and walls) that cause resistance to the cooling air inside and outside the housing. The closer the height of the fins 3a and 3b is to the fan 1, the more the cooling flow path is restricted, making it possible to suppress attenuation of the cooling air due to interference between the cooling air streams, and thus enabling more efficient cooling.

[0025] The shaft side of the fin 3a and the through holes 100 on the surface of the end bracket are in contact, and the narrower the interval, the better, and the fewer steps and gaps there are. The narrower the interval between the circumferentially continuous through holes 100, the larger the surface area of ​​the through holes can be secured, and the greater the cooling effect. However, the axial thickness of the end bracket 3 becomes thinner, and the strength decreases accordingly.

[0026] In order to ensure strength while improving the cooling effect and to send cooling air to the through-holes 100 on the surface of the non-load-side end bracket 3, the fins 3a are partially branched in two directions at the branching point with the fins 3b and angled in the circumferential direction. This allows the fins 3a to be arranged so as to guide the cooling air from the fan 1 to the through-holes 100, and the circumferential intervals of the fins 3a can be kept constant, making it possible to cool from multiple directions and improving the cooling effect. Alternatively, the fins 3a may not be branched, but may be made thicker and wider to the interval between the through-holes 100.

[0027] The taper 3C at the center of the non-load side end bracket 3 is a truncated cone, but it may be a polygonal pyramid, hemisphere, or funnel shape, and is not limited to a truncated cone. Here, the smaller the surface area of ​​the surface parallel to the fan 1, the more likely it is that a higher cooling effect will be obtained, since the offset of the cooling air caused by the rebound of the cooling air from the surface can be reduced. It is preferable that there are no steps or gaps between the truncated cone and the through hole 100.

[0028] The through hole 101 provided in the load side end bracket 8 is provided in the radial direction with respect to the shaft 10. The location of the hole is not particularly important, but by providing the hole in the upper part of the rotating machine, the air heated inside the motor goes up, which has the effect of making it easier to release the heat inside. The upper part of the rotating machine can be said to be the direction in which the cooling air rises. In addition, the hole may be provided with a tapered hole so that it becomes narrower from the inside of the motor to the outside. In that case, the surface area of ​​the internal hole becomes larger, and the ventilation resistance becomes smaller than the outer diameter, so that the air inside can escape more easily to the outside, while it becomes difficult for outside air to enter from the outside to the inside, reducing the risk of foreign objects such as dust entering the inside of the motor. Alternatively, a filter or the like may be provided.

[0029] As another example of the through hole 101 provided in the load side end bracket 8 , a plurality of holes may be provided in the shaft 10 direction, similar to the through hole 100 provided in the anti-load side end bracket 3 . Further, instead of providing the through hole 101 in the load side end bracket 8, it may be provided in the load side end of the housing 7.

[0030] In the extension direction of the shaft 10 on the counter load side, a separately excited fan 1 that generates cooling air is supported by a fan cover 2 and disposed. A separately excited fan is a fan that is driven by a motor or the like separate from the rotating electric machine. In order to prevent the intake of foreign matter such as dust, for example, a filter or the like may be provided between the fan 1 and the fan cover 2 in the axial direction on the load side.

[0031] It should be noted that the present invention is not limited to a separately excited fan, but may also be a self-excited fan. Figure 7 shows an embodiment of a motor using a self-excited fan. A fan 1 is connected to the anti-load side of a shaft (rotating shaft) 10, and generates cooling air by rotating together with the shaft 10. The fan may be installed on either the load side or the anti-load side. In the case of being installed on the anti-load side, the installation structure can be easily constructed, and also the number of man-hours required for components can be reduced.

[0032] As shown in FIG. 6, the fan cover 2 is preferably positioned so as to cover from the fan 1 to the anti-load end of the housing 7, and so that the air blown out from the fan cover 2 flows along the housing 7.

[0033] In this embodiment, the vicinity of the shaft center of the end bracket 3 on the opposite load side is formed into a roughly frustum shape to improve the circulation efficiency of the cooling air. However, for example, when the rotating electric machine is a servo motor, an encoder for measuring the rotation speed or the like may be built in the end bracket 3 on the opposite output shaft side. It is also possible to configure the inside of the frustum-shaped end bracket 3 as a space for incorporating an encoder. In particular, in a configuration requiring an encoder, it is not possible to install a self-excited fan on the opposite output shaft side, and a cooling structure using a separately excited fan may be used. Applying the configuration of this embodiment to a servo motor can improve the cooling efficiency while maintaining the installation configuration and space of the encoder, and can be said to be one of the particularly suitable application examples. EXAMPLES

[0034] Fig. 8 shows the anti-load side end bracket 3 of the second embodiment. On the shaft 10 side, i.e., on the taper 3C at the center, multiple fins 3c are provided from the axis center toward the through hole 100. As shown in Fig. 8, by providing the fins 3c circumferentially on the taper 3C of the third taper part of the anti-load side end bracket 3, a flow path for the cooling air is formed, which reduces interference between the cooling air streams and allows as much cooling air as possible to be sent to the through hole 100. Also, by similarly branching the inside, the cooling air can be sent to the through hole 100 without wasting space between the through holes. [Explanation of symbols]

[0035] 1 Fan 2 Fan cover 3. Non-load side end bracket 3A First taper section 3a Fin of the first taper section 3B Second taper section 3b Fin of second taper section 3C 3rd taper section 3c Fin of the third taper section 4,9 Bearings 5 Rotor 6 Stator 7. Housing 8 Load side end bracket 10 Shaft (rotating axis) 20 Cooling air 100 Through hole of end bracket on non-load side 101 Load side end bracket through hole

Claims

1. the cooling fan includes a stator, a rotor connected to a rotating shaft, a housing surrounding the stator and the rotor, a counter-load side end bracket connected to the housing, a fan that blows cooling air from the counter-load side end bracket side, and a fan cover that covers from the fan to the counter-load side end of the housing, A rotating electric machine, wherein the anti-load side end bracket has a first through hole that allows cooling air to pass inside the housing, a first tapered portion having an apex between the first through hole and an outer periphery of the anti-load side end bracket and inclined in the load direction from the apex to the first through hole, a second tapered portion inclined in the load direction from the apex to the outer periphery of the anti-load side end bracket, and a third tapered portion located between the rotating shaft and the first through hole and inclined in the load direction from the rotating shaft to the first through hole.

2. The rotating electric machine according to claim 1 , wherein the first tapered portion has a plurality of fins for directing cooling air to the first tapered portion to the first through hole.

3. 3. The rotating electric machine according to claim 2, wherein the second tapered portion has a plurality of fins for directing cooling air to an outer periphery of the non-load side end bracket.

4. 4. The rotating electric machine according to claim 3, wherein the fins of the first tapered portion and the fins of the second tapered portion are connected in an outer circumferential direction from the rotating shaft to the anti-load side end bracket.

5. the counter-load side end bracket has a plurality of the first through holes, The first through holes are arranged circumferentially around the rotation axis in a plan view in the rotation axis direction, The rotating electric machine according to claim 2 , wherein the fins of the adjacent first tapered portions extend from the apex to respective ends of the adjacent first through holes.

6. The rotating electric machine according to claim 1 , wherein the third tapered portion has a plurality of fins for guiding the cooling air to the third tapered portion to the first through hole.

7. A load side end bracket is provided for connection to the housing, The rotating electric machine according to claim 1 , wherein the load side end bracket has a second through hole for discharging the cooling air blown into the housing through the first through hole.

8. The rotating electric machine according to claim 7 , wherein the second through hole is provided in a direction in which cooling air rises.

9. The rotating electric machine according to claim 7 , wherein the second through hole is provided in a direction of the rotation axis.

10. The rotating electric machine according to claim 1 , wherein the fan is located inside the apex in a direction from the rotating shaft toward an outer periphery of the anti-load side end bracket in a cross-sectional view along the rotating shaft direction.

11. The rotating electric machine according to claim 1 , wherein the fan is a separately excited fan.

12. The rotating electric machine according to claim 1 , wherein the fan is a self-excited fan connected to the rotating shaft.

13. The rotating electric machine is a servo motor, 2. The rotating electric machine according to claim 1, wherein an encoder is built into the non-load side end bracket.

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