A method for improving the temperature rise of a motor by using cross internal circulation ventilation

Abstract

The present invention relates to a method for improving the temperature rise of a motor by using cross internal circulation ventilation. Centering on the rotating shaft, first axial ventilation holes and second axial ventilation holes are sequentially arranged on the rotor at equal intervals and evenly. The air inlet ends of the first axial ventilation holes and the second axial ventilation holes are arranged in opposite directions. Sealing pipes for closing with the radial ventilation grooves are respectively installed at the air inlet ends of the two groups of axial ventilation holes, and plugs for cooling the rotor windings and stator windings at the other end through the radial ventilation grooves are respectively installed at the air outlet ends of the two groups of axial ventilation holes. An internal circulation axial flow fan is correspondingly arranged at the air inlet end of one of the groups of axial ventilation holes. Compared with the prior art, the present invention has balanced heat dissipation, can make the temperature rises of the rotor windings in sections A and B and the temperatures of the bearings at ends A and B tend to be consistent, and is beneficial to improving problems such as the reduction of the motor material utilization rate, the power / weight density, and the power / volume density caused by unbalanced heat dissipation.

Description

Technical Field

[0001] The present invention relates to the technical field of enclosed box motors, and in particular to a method for improving the temperature rise of a motor by using cross internal circulation ventilation. Background Art

[0002] Enclosed box motors with externally mounted (commonly top-mounted) air-air coolers often use IC611, IC616 or IC666 cooling methods. Its cooling air path is composed of a closed-circuit internal air path and an open-circuit external air path, as Figure 1 (IC611), Figure 2 (IC616), Figure 3 (IC666) shown. The closed-circuit internal air path is two symmetric radial ventilation parallel circuits formed by the primary cooling medium (commonly air) inside the closed motor through loop A and loop B. The externally mounted air-air cooler can be installed with an internal air path baffle, and this baffle also plays a supporting role for the air ducts of the external air path. Since the secondary cooling medium (commonly air) of the open-circuit external air path can only flow in from one end (cold end) of the cooler and flow out to the other end (hot end), the heat dissipation effects generated by the primary cooling medium inside the motor in the two parallel loop A and loop B are unbalanced. Loop A exchanges heat with the cold end of the external air path, and loop B exchanges heat with the hot end of the external air path, resulting in a higher winding temperature rise in loop B than that in loop A, and the bearing temperature near loop B is also higher than that near loop A. This unbalanced heat dissipation effect causes a decrease in the material utilization rate of the motor, a decrease in power / weight density, and a decrease in power / volume density. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects existing in the above-mentioned prior art and provide a method for improving the temperature rise of a motor by using cross internal circulation ventilation. To improve the internal cooling of the motor, axial ventilation holes with different air inlet ends are provided on the rotor. By installing sealing pipes and plugs in the axial ventilation holes, the two parallel air-cooled circuits A and B in the internal circulation are transformed into an air-cooled internal circulation in which section A and section B are cross-connected in series, so as to achieve balanced heat dissipation in sections A and B, make the winding temperature rises in sections A and B tend to be the same, and make the bearing temperatures at ends A and B tend to be the same.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] A method for improving the temperature rise of an electric motor by using cross internal circulation ventilation. The electric motor to which this method is applied is an enclosed box-type motor with an externally mounted air-to-air cooler. The electric motor is provided with an internal circulation fan, and the rotor core of the electric motor is provided with radial ventilation grooves. The external air duct of the cooler is provided with a support partition board. The method of the present invention takes the rotating shaft as the center, and the first axial ventilation holes and the second axial ventilation holes are sequentially arranged on the rotor at equal intervals. The air inlet inflow ends of the first axial ventilation holes and the second axial ventilation holes are arranged in opposite directions; sealing pipes for closing with the radial ventilation grooves are respectively installed at the air inlet inflow ends of the first axial ventilation holes and the second axial ventilation holes, and plugs for cooling the other end of the rotor winding and the stator winding through the radial ventilation grooves are respectively installed at the air outlet ends of the first axial ventilation holes and the second axial ventilation holes.

[0006] Further, the sum of the lengths of the sealing pipes installed in the first axial ventilation holes and the lengths of the sealing pipes installed in the second axial ventilation holes is the same as the length of the rotor core.

[0007] Further, if the lengths of the sealing pipes installed at the air inlet inflow ends of the first axial ventilation holes and the second axial ventilation holes are different, the position of the support partition board of the external air duct of the cooler is the same as the separation position of the two sealing pipes corresponding to the two axial ventilation holes.

[0008] The method for improving the temperature rise of an electric motor by using cross internal circulation ventilation provided by the present invention has at least the following beneficial effects compared with the prior art:

[0009] 1. In the present invention, axial ventilation holes with different air inlet inflow ends are sequentially arranged on the rotor at equal intervals with the rotating shaft as the center. By installing sealing pipes and plugs in the axial ventilation holes, the existing A and B air-cooling loop structures in parallel in the internal circulation are transformed into an air-cooling internal circulation in which section A and section B are cross-connected in series, so that the heat generated by the windings and the iron cores of sections A and B flows through the same loop, and cross heat exchange occurs with both the cold end and the hot end of the external air duct, obtaining an approximately same heat dissipation effect, basically achieving heat dissipation balance between sections A and B, making the temperature rises of the windings in sections A and B tend to be the same, and the temperatures of the bearings at ends A and B tend to be the same, which is beneficial to improving problems such as the reduction of the material utilization rate of the electric motor, the reduction of the power / weight density, and the reduction of the power / volume density caused by unbalanced heat dissipation;

[0010] 2. The position of the partition board in the cooler is set as the separation position of the lengths of the sealing pipes in sections A and B. By adjusting the lengths of the sealing pipes in sections A and B, the temperatures of the bearings at ends A and B can be further made to tend to be the same;

[0011] 3. The present invention is applicable to various enclosed motors with external cooling structures and uneven heat dissipation between the cold and hot ends, and can be combined with other cooling structures. Description of the Drawings

[0012] Figure 1 It is a schematic structural diagram of the cooling air path in the IC611 mode of a closed-box motor in the prior art;

[0013] Figure 2 It is a schematic structural diagram of the cooling air path in the IC616 mode of a closed-box motor in the prior art;

[0014] Figure 3 It is a schematic structural diagram of the cooling air path in the IC666 mode of a closed-box motor in the prior art;

[0015] Figure 4 It is a schematic structural diagram of the cooling air path in the IC611 mode of a closed-box motor improved based on the method of using cross internal circulation ventilation to improve the motor temperature rise in Embodiment 1;

[0016] Figure 5 It is a schematic structural diagram of the cooling air path in the IC616 mode of a closed-box motor improved based on the method of using cross internal circulation ventilation to improve the motor temperature rise in Embodiment 1;

[0017] Figure 6 It is a schematic structural diagram of the cooling air path in the IC666 mode of a closed-box motor improved based on the method of using cross internal circulation ventilation to improve the motor temperature rise in Embodiment 1;

[0018] Figure 7 It is a schematic diagram of the installation positions of the sealing pipes and plugs in Embodiment 1;

[0019] Figure 8 It is a schematic structural diagram of the single-row axial ventilation holes of the rotor in Embodiment 1;

[0020] Figure 9 It is a schematic structural diagram of the double-row axial ventilation holes of the rotor in Embodiment 1;

[0021] Figure 10 It is a schematic structural diagram of the cooling air path in the IC611 mode of a closed-box motor improved based on the method of using cross internal circulation ventilation to improve the motor temperature rise in Embodiment 2;

[0022] Figure 11 It is a schematic structural diagram of the cooling air path in the IC616 mode of a closed-box motor improved based on the method of using cross internal circulation ventilation to improve the motor temperature rise in Embodiment 2;

[0023] Figure 12 It is a schematic structural diagram of the cooling air path in the IC666 mode of a closed-box motor improved based on the method of using cross internal circulation ventilation to improve the motor temperature rise in Embodiment 2;

[0024] As indicated by the reference numerals in the figure:

[0025] 1. External air duct fan, 2. Rotor winding, 3. Stator winding, 4. Cooler support plate, 5. Support partition board, 6. Stator core, 7. Rotor core, 8. Cold end bearing, 9. Shaft, 10. Cooler, 11. Motor, 12. Radial ventilation groove, 13. Axial ventilation hole, 14. Hot end bearing, 15. Plugging, 16. Sealing pipe, 17. Inner circulation axial flow fan. Detailed implementation mode

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention.

[0027] Embodiment 1

[0028] The present invention relates to a method for improving the temperature rise of a motor by using cross inner circulation ventilation, which is applied to a closed box-type motor with an externally mounted (commonly top-mounted) air-to-air cooler. This method transforms the existing A and B air-cooled loop structures in parallel in the inner circulation into a single air-cooled inner circulation in which section A and section B are cross-connected in series, so that the windings and bearings at both ends of the motor can dissipate heat evenly.

[0029] Figures 1 - 3 The assembly structure of the stator, rotor and cooler of a closed box-type motor with an externally mounted air-to-air cooler in the prior art is shown, and the schematic diagrams of the air-cooled loops of different cooling methods (IC611 method, IC616 method and IC666 method) are shown. An external air duct fan 1 is provided at one end of the cooler. Under the action of the external air duct fan 1, the secondary cooling air flows in from the cold end of the air-to-air cooler, and after heat exchange, the heat in the motor is discharged from the hot end. A support partition board 5 can be provided in the middle of the external air duct of the cooler. For the IC611 and IC616 cooling methods, inner circulation axial flow fans 17 are installed at both ends of the rotating shaft 9 to form the power source of the primary inner circulation air path; for the IC666 cooling method, a centrifugal fan is installed above the middle of the air-to-air cooler to form the power source of the primary inner circulation air path. Axial ventilation holes 13 are evenly distributed on the rotor, and radial ventilation grooves 12 are provided on the stator core 6 and the rotor core 7.

[0030] The method of the present invention divides the axially ventilated holes evenly distributed on the rotor into two groups a and b at intervals of one hole. Specifically: for the single-row ventilation hole setting structure, as Figure 8 shown, the present invention arranges the axially arranged group a ventilation holes and group b ventilation holes at equal intervals in turn. For the double-row ventilation hole setting structure, as Figure 9As shown, each set of axially arranged a ventilation holes and b ventilation holes are equally spaced in turn around the rotor shaft. The two circles formed by the two layers of ventilation holes are concentric circles. The inner and outer layer ventilation holes are arranged symmetrically and staggeredly. For the IC611 and IC616 cooling methods, the internal circulation axial flow fan 17 is correspondingly arranged with the air inlet end of one group of ventilation holes. The air inlet end of group a ventilation holes is arranged opposite to the air inlet end of group b ventilation holes. That is, the air inlet end of group a ventilation holes is the cold end air inlet end, and the air inlet end of group b ventilation holes is the hot end air inlet end, or the air inlet end of group a ventilation holes is the hot end air inlet end, and the air inlet end of group b ventilation holes is the cold end air inlet end. The group a ventilation holes and group b ventilation holes can be cylindrical holes or other shapes. The following content takes the air inlet end of group a ventilation holes as the cold end air inlet end, the air inlet end of group b ventilation holes as the hot end air inlet end, and the internal circulation axial flow fan 17 is correspondingly arranged with the air inlet end of group a ventilation holes as an example for explanation.

[0031] After arranging the group a ventilation holes and group b ventilation holes according to the above distribution method, seal pipes 16 are arranged at the A section where the air flows into all the group a ventilation holes to seal the space between the axial ventilation holes in the A section and the radial ventilation grooves 12, as Figure 4 , 5 , and shown in 6. And a plug 15 is arranged at the end of the B section of the group a ventilation holes, so that the primary cooling medium flowing through the group a ventilation holes in the A section of the rotor cools the rotor winding and stator winding in the B section of the rotor through the radial ventilation grooves 12, as Figure 4 , 5 , and shown in 6. Similarly, seal pipes 16 are arranged at the B section where the air flows into all the group b ventilation holes to seal the space between the axial ventilation holes in the B section and the radial ventilation grooves 12, as Figure 4 , 5 , and shown in 6. And a plug 15 is arranged at the end of the A section of the group b ventilation holes, so that the primary cooling medium flowing through the group b ventilation holes in the B section of the rotor cools the rotor winding and stator winding in the A section of the rotor through the radial ventilation grooves 12, as Figure 4 , 5 , and shown in 6. In this way, the existing parallel A and B circuits are transformed into an A and B cross-connected series circuit. Therefore, the heat generated by the windings and iron cores in both the A and B sections flows through the same circuit, and cross heat exchange occurs with both the cold end and hot end of the external air path, obtaining an approximately same heat dissipation effect. Basically, the heat dissipation of both the A and B sections can be balanced, making the temperature rise of the windings in the A and B sections tend to be the same, and the temperatures of the bearings at the A and B ends tend to be the same. The sum of the lengths of the seal pipes arranged at the A section of the group a ventilation holes and the lengths of the seal pipes arranged at the B section of the group b ventilation holes is equal to the length of the rotor core 7.

[0032] In this embodiment, as a preferred solution, the length of the sealing pipe 16 provided in section A where the air inlet of the a-group ventilation holes flows in is equal to the length of the sealing pipe 16 provided in section B where the air inlet of the b-group ventilation holes flows in, so that sections A and B are symmetric structures, and basically the heat dissipation effects of sections A and B can tend to be balanced.

[0033] Embodiment 2

[0034] When improving the cooling air path based on Embodiment 1, there is still a small amount of unevenness in the bearing temperatures at both ends A and B. The symmetrically arranged sections A and B can be changed to an asymmetric structure. That is, the lengths of the sealing pipes 16 in the original sections A and B, which were equal, are changed to unequal lengths, and the position of the support partition plate 5 of the air duct outside the cooler is made consistent with the separation position of the lengths of the sealing pipes 16 in sections A and B, as shown in Figure 10 , 11 , 12. By adjusting the lengths of the sealing pipes 16 in sections A and B, the bearing temperatures at both ends A and B can be further made to tend to be the same.

[0035] In the description of the present invention, it should be noted that for orientation terms, such as "axial direction", "outer circle", "air inlet end", etc., the indicated orientation and positional relationship are based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. For the description of shapes, such as "circular" and "cylindrical", it is also limited to the shapes shown in the drawings. These orientation terms and shape descriptions should not be understood as limiting the specific protection scope of the present invention.

[0036] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for improving the temperature rise of an electric motor by using cross internal circulation ventilation, the electric motor being an enclosed box-type motor with an externally mounted air-to-air cooler, the electric motor being provided with an internal circulation fan, the rotor core of the electric motor being provided with radial ventilation grooves, and the external air duct of the cooler being provided with support partition plates, characterized in that, With the rotating shaft as the center, a first axial ventilation hole and a second axial ventilation hole are sequentially arranged on the rotor at equal intervals. The air inlet end of the first axial ventilation hole and the air inlet end of the second axial ventilation hole are arranged in opposite directions. Sealing pipes for closing with the radial ventilation groove are respectively installed at the air inlet ends of the first axial ventilation hole and the second axial ventilation hole, and plugs for cooling the rotor winding and stator winding at the other end through the radial ventilation groove are respectively installed at the air outlet ends of the first axial ventilation hole and the second axial ventilation hole. The sum of the lengths of the sealing pipes installed in the first axial ventilation hole and the lengths of the sealing pipes installed in the second axial ventilation hole is the same as the length of the rotor core. If the lengths of the sealing pipes installed at the air inlet ends of the first axial ventilation hole and the air inlet ends of the second axial ventilation hole are different, the setting position of the support partition plate of the external air duct in the cooler is the same as the separation position of the two sealing pipes corresponding to the two axial ventilation holes.

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