GB2577571A

GB2577571A - Stator, rotor, and electrical machine with thermal benefits

Info

Publication number: GB2577571A
Application number: GB1816803.9A
Authority: GB
Inventors: Zhang Fengyu; Gerada Christopher; Daniel Gerada David; Xu Zeyuan; Zhang He; Galea Michael; James Frederick Tighe Christopher
Original assignee: University of Nottingham Ningbo China
Current assignee: University of Nottingham Ningbo China
Priority date: 2018-09-29
Filing date: 2018-10-16
Publication date: 2020-04-01
Anticipated expiration: 2038-10-16
Also published as: GB2577571B; CN114530991A; GB201816803D0; CN109391090A

Abstract

A stator with thermal benefits, comprising: a stator yoke 110; plurality of regular teeth 120; plurality of stator slots 130, wherein the slots and regular teeth are aligned in a circle between the yoke and stator centre, each slot is located between two regular teeth, and each of the slots comprises one slot opening, a bottom wall adjacent to the stator yoke and two side walls adjacent to the slot opening; and a plurality of dummy teeth 140, extended from the bottom or side walls; wherein a first width W1 of the stator slot is larger than a second width W2 of the dummy teeth. The dummy teeth may extend radially inward from the bottom wall, wherein slots per tooth ratio may vary. The dummy teeth may be trapezoidal or rectangular shaped. A similar design maybe applied to a slotted rotor. The stator or rotor maybe the first component of an electrical machine, the first component having a first thermal conductivity; and a second component adjacent to it having a second thermal conductivity; wherein the second conductivity is higher than the first and wherein heat generated near the first is transferred to the second component, and is dissipated to coolant of the machine by the second component.

Description

STATOR, ROTOR, AND ELECTRICAL MACHINE WITH THERMAL BENEFITS FIELD OF THE DISCLOSURE The present disclosure relates to the field of electrical machines and electrical machine components, in particular to electrical machines, stators and rotors with thermal benefits. BACKGROUND OF THE INVENTION Most losses in electrical machines and machine components are winding losses generated within the slots. Moreover, the thermal resistance in the slot is large, making heat generated in the slot difficult to be dissipated by the coolant employed. Therefore, generally, the hot spot of the electrical machine is typically located in the center of the slot. The aforesaid hot spot in the middle of the slot limits the life of the insulation, and is often one of the primary constraints on the power which can be delivered by the electrical machine.

The existing thermal technology on electrical machines focus on the motor structure heat transfer ability between the motor and cooling medium, to improve the heat transfer coefficient between the motor and cooling medium, and to increase the contact surface area. Traditional cooling methods, for example, improve fin dimensions and its numbers in natural convection to increase the contact surface area between the motor and ambient air. Different coolant channel designs are explored in forced convection to increase the heat transfer coefficient between the motor and coolant, or to increase the contact surface area.

These aforesaid technical solutions increase the heat dissipation capacity, but the insulation material life span and the motor maximum output torque are still limited by the winding temperature in the slot. If the heat generated in the slot can be effectively transferred to the cooling medium, then motor thermal environment can be greatly improved, thus extending motor life span and increasing output torque value.

Hence, how to provide an electrical machine and electrical machine components capable of solving the above-mentioned problems has become an important topic for the person skilled in the art.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems, an electrical machine, a stator and a rotor with thermal benefits are provided in the present disclosure.

It is one objective of the present disclosure to provide an electrical machine with thermal benefits.

According to one exemplary embodiment of the present disclosure, an electrical machine with thermal benefits is provided. The electrical machine includes a first electrical machine component and a second electrical machine component. The first electrical machine component is configured to generate loss and has a first thermal conductivity. The second electrical machine component is disposed adjacent to the first electrical machine component and has a second thermal conductivity. The second thermal conductivity is higher than the first thermal conductivity, wherein heat generated near the first electrical machine component is transferred to the second electrical machine component, and is dissipated to coolant of the electrical machine by the second electrical machine component.

In some embodiments, the first electrical machine component may be a stator or a rotor.

It is one objective of the present disclosure to provide a stator with thermal benefits.

According to one exemplary embodiment of the present disclosure, a stator with thermal benefits is provided. The stator includes a stator yoke, a plurality of regular teeth, a plurality of stator slots, and a plurality of dummy teeth. The plurality of stator slots and the plurality of regular teeth are aligned in a circle between the stator yoke and a center of the stator, each stator slot is located between two regular teeth, and each of the plurality of stator slots includes one slot opening, a bottom wall adjacent to the stator yoke and two side walls adjacent to the slot opening. The plurality of dummy teeth is extended from the bottom wall or the two side walls of the plurality of stator slots. A first width of the stator slot is larger than a second width of the dummy teeth, and a third width of the regular teeth is larger than the second width of the dummy teeth.

In one example, each of the plurality of dummy teeth is extended radially inward from the bottom wall of the stator slot to the center of the stator.

In one example, each of the plurality of dummy teeth is extended from the two side walls of the stator slot to the interior of the stator slot.

In one example, a number of the plurality of stator slots is n, and a number of the dummy teeth is n, 3n, 5n, 7n, or more.

In one example, a number of the plurality of stator slots is n, and a number of the dummy teeth is n, n/2, n/3, n/4, or less.

In one example, each of the plurality of dummy teeth further includes a main part and a plurality of fins. A centerline of the main part coincides with a symmetry axis of the stator slot, and the plurality of fins, placed on two sides of the main part. If a number of the dummy teeth is m, a number of the fins is 2m, 4m, 6m or more.

In one example, each of the plurality of dummy teeth includes a trapezoidal shape or a rectangular shape.

In one example, a depth of the stator slot is L, and a length of the dummy teeth is 2/5L to 5/5L.

In one example, the plurality of stator slots has a first thermal conductivity, the plurality of dummy teeth has a second thermal conductivity, and the second thermal conductivity of the dummy teeth is higher than the first thermal conductivity of the stator slot.

According to one exemplary embodiment of the present disclosure, a rotor with thermal benefits is provided. The rotor includes a shaft, a rotor yoke, a plurality of regular teeth, a plurality of rotor slots, and a plurality of dummy teeth. The shaft is located in a center of the rotor. The rotor yoke is located around the rotor shaft. The plurality of rotor slots and the plurality of regular teeth are aligned in a circle around the rotor yoke, and each rotor slot is located between every two regular teeth. Each of the plurality of rotor slots includes one slot opening, a bottom wall adjacent to the rotor yoke and two side walls adjacent to the slot opening. The plurality of dummy teeth is extended from the bottom wall or the two side walls of the plurality of rotor slots. A first width of the rotor slot is larger than a second width of the dummy teeth, and a third width of the regular teeth is larger than the second width of the dummy teeth.

In one example, each of the plurality of dummy teeth is extended radially outward from the bottom wall of the rotor slot to the slot opening of the rotor slot.

In one example, each of the plurality of dummy teeth is extended from the two side walls of the rotor slot to the interior of the rotor slot.

In one example, a number of the plurality of rotor slots is n, and a number of the dummy teeth is n, 3n, 5n, 7n, or more.

In one example, a number of the plurality of rotor slots is n, and a number of the dummy teeth is n, n/2, n/3, n/4, or less.

In one example, each of the plurality of dummy teeth further includes a main part and a plurality of fins. A centerline of the main part coincides with a symmetry axis of the rotor slot. The plurality of fins is placed on two sides of the main part. If a number of the dummy teeth is m, a number of the fins is 2m, 4m, 6m or more.

In one example, each of the plurality of dummy teeth comprises a trapezoidal shape or a rectangular shape.

In one example, a depth of the stator slot is L, and a length of the dummy teeth is 2/5L to 5/.5L.

In one example, the plurality of rotor slots has a first thermal conductivity, the plurality of dummy teeth has a second thermal conductivity, and the second thermal conductivity of the dummy teeth is higher than the first thermal conductivity of the rotor slot.

According to one exemplary embodiment of the present disclosure, an electrical machine with thermal benefits is provided. The electrical machine includes a housing, a stator and a rotor having the abovementioned features stated in the embodiments of the present disclosure.

These and other objectives of the present disclosure will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of preferred embodiments illustrated with reference to various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. I is a schematic diagram of a stator according to a first embodiment of the present disclosure. FIG. 2 is a schematic diagram of a stator according to a second embodiment of the present disclosure. FIG. 3 is a schematic diagram of a stator according to a third embodiment of the present disclosure. FIG. 4 is a schematic diagram of a stator according to a fourth embodiment of the present disclosure. FIG. 5 is a schematic diagram of a stator according to a fifth embodiment of the present disclosure. FIG. 6 is a schematic diagram of a stator according to a sixth embodiment of the present disclosure. FIG. 7 is a schematic diagram of a stator according to a seventh embodiment of the present disclosure. FIG. 8 is a schematic diagram of a stator according to an eighth embodiment of the present disclosure. FIG. 9 is a schematic diagram of a rotor according to a first embodiment of the present disclosure. FIG. 10 is a schematic diagram of a rotor according to a second embodiment of the present disclosure. FIG. 11 is a schematic diagram of a rotor according to a third embodiment of the present disclosure. FIG. 12 is a schematic diagram of an electrical machine according to an embodiment of the present disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Certain terms are used throughout the following descriptions and claims to refer to particular system components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names This document does not intend to distinguish between components that differ in name but not differ in functionality. In the following discussion and in the claims, the terms "include", "including", "comprise", and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to..." The terms "couple" and "coupled" are intended to mean either an indirect or a direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.

The figures are only illustrations of an example, wherein the units or procedure shown in the figures are not necessarily essential for implementing the present disclosure. Those skilled in the art will understand that the units in the device in the example can be arranged in the device in the examples as described, or can be alternatively located in one or more devices different from that in the examples. The units in the examples described can be combined into one module or further divided into a plurality of sub-units.

It is also noted that as used herein and in the appended claims, the singular forms "a", "and", and "the" include plural referents unless the context clearly dictates otherwise. In the claims, the terms "first," "second", and so forth are to be interpreted merely as ordinal designations they shall not be limited in themselves. Further, the use of exclusive terminology such as "solely," "only" and the like in connection with the recitation of any claim element is contemplated. Also, it is contemplated that any element indicated to be optional herein may be specifically excluded from a given claim by way of a "negative" limitation. Finally, it is contemplated that any optional feature of the inventive variation(s) described herein may be set forth and claimed independently or in combination with any one or more of the features described herein.

The present disclosure provides an electrical machine with thermal benefits, which includes a first electrical machine component and a second electrical machine component. The first electrical machine component is configured to generate loss and has a first thermal conductivity. The second electrical machine component is disposed adjacent to the first electrical machine component and has a second thermal conductivity. Generally, the first electrical machine component may be a stator or a rotor.

The second thermal conductivity is higher than the first thermal conductivity, therefore, heat generated near the first electrical machine component is transferred to the second electrical machine component, and is dissipated to coolant of the electrical machine by the second electrical machine component.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a stator 100 according to a first embodiment of the present disclosure. As shown in FIG. 1, the stator 100 includes, but is not limited to, a stator yoke 110, a plurality of regular teeth 120, a plurality of stator slots 130, and a plurality of dummy teeth 140. The plurality of stator slots 130 and the plurality of regular teeth 120 are aligned in a circle between the stator yoke 110 and a center C of the stator 100, each stator slot 130 is located between two regular teeth 120, and each of the plurality of stator slots 130 includes one slot opening 131, a bottom wall 132 adjacent to the stator yoke 110 and two side walls 133A and 133B adjacent to the slot opening 131. The plurality of dummy teeth 140 is extended from the bottom wall 132 or the two side walls 133A and 133B of the plurality of stator slots 130. In this embodiment, each of the plurality of dummy teeth 140 is extended radially inward from the bottom wall 132 of the stator slot 130 to the center C of the stator 100. A first width WI of the stator slot 130 is larger than a second width W2 of the dummy teeth140. In some embodiments, a third width W3 of the regular teeth 120 may be larger than the second width W2 of the dummy teeth 140.

Be noted that, there is one dummy tooth 140 between two adjacent regular teeth 120. That is to say, there is one dummy tooth 140 in each stator slot 130. For example, in FIG. 1, the number of the stator slots 130 is twelve, and the number of the dummy teeth 140 is twelve. Each of the plurality of dummy teeth 140 is extended from a middle point of the bottom wall 132 of the stator slot HO, and then along the symmetry axis of the stator slot 130 to the slot opening 131. In this embodiment, the length of the dummy tooth 140 is 4/5 of the depth of the stator slot 130. However, this is merely one example for describing the technical features of the present disclosure, and should not be considered as a limitation of the present disclosure. In other embodiments, the length of the dummy teeth can be adjustable. For example, if a depth of the stator slot 130 is L, a length of the dummy teeth 140 can be 2/5L to 5/5L.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of a stator 200 according to a second embodiment of the present disclosure. As shown in FIG. 2, the stator 200 includes, but is not limited to, a stator yoke 110, a plurality of regular teeth 120, a plurality of stator slots 130, and a plurality of dummy teeth 140. The stator 200 shown in FIG. 2 is similar to the stator 100 shown in FIG. 1, and the difference between them is that the numbers of the dummy teeth 140 are different. For example, the number of the dummy teeth 140 is twelve in FIG. 1, and the number of the dummy teeth 140 is six in FIG. 2.

Be noted that, in this embodiment, there is only one dummy tooth 140 in every two adjacent stator slots 130. However, this is merely one example for describing the technical features of the present disclosure, and should not be considered as a limitation of the present disclosure. In other embodiment, the number of the dummy teeth 140 can be adjustable. For example, if a number of the stator slots 130 is n, a number of the dummy teeth 140 can be n, n/2, n/3, n/4, or less.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of a stator 300 according to a third embodiment of the present disclosure. As shown in FIG. 3, the stator 300 includes, but is not limited to, a stator yoke 110, a plurality of regular teeth 120, a plurality of stator slots 330, and a plurality of dummy teeth 340A, 340B, and 340C. Each stator slot 330 is located between two regular teeth 120, and each of the plurality of stator slots 330 includes one slot opening 331, a bottom wall 332 adjacent to the stator yoke 110 and two side walls 333A and 333B adjacent to the slot opening 331 Be noted that, there are three dummy teeth 340A, 340B, and 340C in each stator slot 330. For example, in FIG. 3, the number of the stator slots 330 is six, and the number of the dummy teeth is eighteen. However, this is merely one example for describing the technical features of the present disclosure, and should not be considered as a limitation of the present disclosure. In other embodiments, the number of the dummy teeth can be adjustable. For example, if a number of the plurality of stator slots is n, a number of the dummy teeth can be n, 3n, 5n, 7n, or more. If the stator slot 330 has a wider width, there can be more dummy teeth (such as 3n or 5n) in each stator slot 330.

In this embodiment, the three dummy teeth include one left dummy tooth 340A, one middle dummy tooth 340B, and one right dummy tooth 340C. The centerline of the middle dummy tooth 340B coincides with the symmetry axis of the stator slot 330, while the left dummy tooth 340A and the right dummy tooth 340C are symmetrically distributed. That is to say, the three dummy teeth 340A, 340B, and 340C are extended radially inward from the bottom wall 332 of the stator slot 330 to the center C of the stator 300. In one example, the length of the middle dummy tooth 340B is 4/5 of the depth of the stator slot 330, while the length of the left dummy tooth 340A and the right dummy tooth 340C is 2/5 of the depth of the stator slot 330. However, this is merely one example for describing the technical features of the present disclosure, and should not be considered as a limitation of the present disclosure. In other embodiments, the lengths of the left dummy tooth 340A, the middle dummy tooth 340B, and the right dummy tooth 340C can be adjustable.

Be noted that, in FIG. 1 and FIG. 2, each of the dummy teeth 140 of the stator 100/200 has a trapezoidal shape. In FIG. 3, each of the dummy teeth 340A, 340B, and 340C has a rectangular shape. The trapezoidal shape means that the width of the dummy tooth 140 adjacent to the bottom wall 132 is different from the width of the dummy tooth 140 near the slot opening 131. The rectangular shape means that the width of the dummy tooth adjacent to the bottom wall is the same as the width of the dummy tooth adjacent to the slot opening.

In FIG. 1 and FIG. 2, the width of the dummy tooth 140 adjacent to the bottom wall 132 is smaller than the width of the dummy tooth 140 adjacent to the slot opening 131. These two embodiments are easy for conducting heat generated in the hot spot to the dummy teeth 140, and it is also easy for winding procedure. In other embodiment, the dummy teeth can also be designed to have a wider width adjacent to the bottom wall 132 and a smaller width adjacent to the slot opening 131, which should also belong to the technical scope of the present disclosure.

Please refer to FIG. 4. FIG. 4 is a schematic diagram of a stator 400 according to a fourth embodiment of the present disclosure. As shown in FIG. 4, the stator 400 includes, but is not limited to, a stator yoke 110, a plurality of regular teeth 120, a plurality of stator slots HO, and a plurality of dummy teeth 440. Each of the plurality of dummy teeth 440 further includes a main part 441 and a plurality of fins 442, wherein a centerline of the main part 441 coincides with a symmetry axis of the stator slot 130, and the plurality of fins 442 are placed on two sides of the main part 441. In this embodiment, there is one pair of fins 442 placed on two sides of the main part 441. Preferably, the pair of fins 442 and the main part 441 of the dummy tooth 440 are integrally formed. The pair of fins 442 is arranged on two sides of the main part 441 for collecting heat generated in the stator slot 130 and transferring heat to the main part 441, such that the heat dissipation capability of the stator in an electrical machine can be increased.

Please refer to FIG. 5. FIG. 5 is a schematic diagram of a stator 500 according to a fifth embodiment of the present disclosure. As shown in FIG. 5, the stator 500 includes, but is not limited to, a stator yoke 110, a plurality of regular teeth 120, a plurality of stator slots 130, and a plurality of dummy teeth 540. Each of the plurality of dummy teeth 640 further includes a main part 541 and a plurality of fins 542 and 543. The stator 500 shown in FIG. 5 is similar to the stator 400 shown in FIG. 4, and the difference between them is that the numbers of the fins are different. For example, there is one pair of fins 442 placed on two sides of the main part 441 in FIG. 4, while there are two pairs of fins 542 and 543 placed on two sides of the main part 541 in FIG. 5. One pair of fins 542 is disposed in the middle of the main part 541, and the other pair of fins 543 is disposed near the slot opening 131. However, the number of the fins should not be considered as a limitation of the present disclosure. In other embodiments, the number of the fins can be adjustable. For example, if a number of the dummy teeth is m, a number of the fins can be 2m, 4m, 6m or more.

Please note that, the number of fins can be determined based on the depth of the stator slot 130, and the lengths of the fins can be determined based on the width of the stator slot 130. In one example, the fins 542 and 543 have an angle of 45 degrees with respect to the main part 541 of the dummy tooth 540, which can simplify the winding procedure and stabilize the winding arrangement. However, this angle can be adjustable and should not be considered as a limitation of the present disclosure. Preferably, the width of the main part 541 of the dummy tooth 540 can be around 5% to 20% of the width of the stator slot 130.

Please refer to FIG. 6. FIG. 6 is a schematic diagram of a stator according to a sixth embodiment of the present disclosure. As shown in FIG. 6, the stator 600 includes, but is not limited to, a stator yoke 610, a plurality of regular teeth 620, a plurality of stator slots 630, and a plurality of dummy teeth 640. Each stator slot 630 is located between two regular teeth 620, and each of the plurality of stator slots 630 includes one slot opening 631, a bottom wall 632 adjacent to the stator yoke 610 and two side walls 633A and 633B adjacent to the slot opening 631. Be noted that, each of the plurality of dummy teeth 640 is extended from the two side walls 633A and 633B of the stator slot 630 to the interior of the stator slot 630. In other words, each of the plurality of dummy teeth 640 is extended from the regular teeth 620. The dummy teeth 640 have same material with the regular teeth 620, and the thermal conductivity of the dummy teeth 640 (or the regular teeth 620) is much higher than the equivalent thermal conductivity, which is easy to manufacture.

In this embodiment, there are four dummy teeth 640 in each stator slot 630. However, the number of the dummy teeth 640 should not be considered as a limitation of the present disclosure. In other embodiments, the number of the dummy teeth 640 can be adjustable. For example, if a number of the plurality of stator slots is n, a number of the dummy teeth can be 2n, 4n, 6n, or more. In another embodiment, if a number of the plurality of stator slots is n, the number of the dummy teeth 640 can be 2n, 2n/2, 2n/3, 2n/4, or less. For example, there is only one pair of dummy teeth 640 in every two adjacent stator slots 630 or in every three adjacent stator slots 630. The stator 600 shown in FIG. 6 is suitable for narrow and deep slots.

In this embodiment, each of the dummy teeth 640 of the stator 600 has a rectangular shape, however, in other embodiments, each of the dummy teeth 640 of the stator 600 can be designed to have a trapezoidal shape (not shown), which should also belong to the technical scope of the present disclosure. In another embodiment, each of the plurality of dummy teeth 640 can be designed to further include a main part and a plurality of fins (not shown). Preferably, the plurality of fins and the main part of the dummy tooth 640 are integrally formed, and the fins are arranged on two sides of the main part of the dummy tooth 640. Be noted that, the number of the fins should not be considered as a limitation of the present disclosure, and the number of the fins can be adjustable. For example, if a number of the dummy teeth is m, a number of the fins can be 2m, 4m, 6m or more.

Please refer to FIG. 7. FIG. 7 is a schematic diagram of a stator according to a seventh embodiment of the present disclosure. As shown in FIG. 7, the stator 700 includes, but is not limited to, a stator yoke 710, a plurality of regular teeth 720, a plurality of stator slots 730, and a plurality of dummy teeth 740. The stator 700 shown in FIG. 7 is similar to the stator 600 shown in FIG. 6, and the difference between them is that the dummy teeth 740 and the regular teeth 720 of the stator 700 have different materials. For example, the material of the dummy teeth 740 is ceramic and the material of the regular teeth 720 is lamination, the thermal conductivity of ceramic is much higher than the regular teeth 720 and the equivalent thermal conductivity inside the stator slot 730, which can help to conduct heat generated in the stator slot 730 more effectively to the regular teeth 720 and then to the coolant (not shown).

Please refer to FIG. 8. FIG. 8 is a schematic diagram of a stator according to an eighth embodiment of the present disclosure. As shown in FIG. 8, the stator 800 includes, but is not limited to, a stator yoke 110, a plurality of regular teeth 120, a plurality of stator slots 830, and a plurality of dummy teeth 840A, 840B, and 840C. Each stator slot 830 is located between two regular teeth 120, and each of the plurality of stator slots 830 includes one slot opening 831, a bottom wall 832 adjacent to the stator yoke 110 and two side walls 833A and 833B adjacent to the slot opening 831.

Be noted that, there are three dummy teeth 840A, 8408, and 840C in each stator slot 830. For example, in FIG. 8, the number of the stator slots 830 is six, and the number of the dummy teeth is eighteen. However, this is merely one example for describing the technical features of the present disclosure, and should not be considered as a limitation of the present disclosure. In other embodiments, the number of the dummy teeth can be adjustable. For example, if a number of the plurality of stator slots is n, a number of the dummy teeth can be n, 3n, 5n, 7n, or more. If the stator slot 830 has a wider width, there can be more dummy teeth (such as 3n or 5n) in each stator slot 830.

In this embodiment, the three dummy teeth include one left dummy tooth 840A, one middle dummy tooth 8408, and one right dummy tooth 840C. The centerline of the middle dummy tooth 840B coincides with the symmetry axis of the stator slot 830. Be noted that, the middle dummy tooth 840B is extended radially inward from the bottom wall 832 of the stator slot 830 to the center C of the stator 800, while the left dummy tooth 840A and the right dummy tooth 840C are extended from the side walls 833A and 833B of the stator slot 830 (i.e., extended from the regular teeth 120). The middle dummy tooth 840B can separate the stator slot 830 into half by conducting heat effectively generated in the middle of the stator slot 830. The left dummy tooth 840A and the right dummy tooth 840C can help to conduct the heat generated in the middle of the separated stator slot 830 to the regular tooth 120 and then to the coolant. This embodiment can be a replacement for the embodiment shown in FIG. 3 with a wide stator slot. This embodiment is also a combination of the embodiments shown in FIG. 1 and FIG.6.

Please note that, in the abovementioned embodiments shown in FIG. 1-FIG. 8, the plurality of stator slots have a first thermal conductivity, the plurality of dummy teeth have a second thermal conductivity, and the second thermal conductivity of the dummy teeth is higher than the first thermal conductivity of the stator slot.

Please refer to FIG. 9. FIG. 9 is a schematic diagram of a rotor 900 according to a first embodiment of the present disclosure. As shown in FIG.9, the rotor 900 may include, but is not limited to, a shaft 950, a rotor yoke 910, a plurality of regular teeth 920, a plurality of rotor slots 930, and a plurality of dummy teeth 940. The shaft 950 is located in a center C of the rotor 900. The rotor yoke 910 is located around the rotor shaft 950. The plurality of rotor slots 930 and the plurality of regular teeth 920 are aligned in a circle around the rotor yoke 910, and each rotor slot 930 is located between two regular teeth 920. Each of the plurality of rotor slots 930 includes one slot opening 931, a bottom wall 932 adjacent to the rotor yoke 910 and two side walls 933A and 933B adjacent to the slot opening 931. The plurality of dummy teeth 940 is extended from the bottom wall 932 or the two side walls 933A and 933B of the plurality of rotor slots 930. In this embodiment, each of the plurality of dummy teeth 940 is extended radially outward from the bottom wall 932 of the rotor slot 930 to the slot opening 931 of the rotor slot 930. A first width W11 of the rotor slot 930 is larger than a second width W22 of the dummy teeth 940, and a third width W33 of the regular teeth 920 is larger than the second width W22 of the dummy teeth 940.

Be noted that, there is one dummy tooth 940 between every two adjacent regular teeth 920. That is to say, there is one dummy tooth 940 in each rotor slot 930. For example, in FIG. 9, the number of the rotor slots 930 is twelve, and the number of the dummy teeth 940 is twelve. However, this is merely one example for describing the technical features of the present disclosure, and should not be considered as a limitation of the present disclosure. In other embodiment, the number of the dummy teeth 1040 can be adjustable. For example, if a number of the rotor slots 930 is n, a number of the dummy teeth 940 can be n, n/2, n/3, n/4, or less. In another embodiment, if a number of the plurality of rotor slots 930 is n, a number of the dummy teeth can be n, 3n, 5n, 7n, or more. If the rotor slot 930 has a wider width, there can be more dummy teeth (such as 3n or 5n) in each rotor slot 930.

The plurality of dummy teeth 940 is extended from a middle point of the bottom wall 932 of the rotor slot 930, and then along the symmetry axis of the rotor slot 930 to the slot opening 931. In this embodiment, the length of the dummy tooth 940 is 4/5 of the depth of the rotor slot 930. However, this is merely one example for describing the technical features of the present disclosure, and should not be considered as a limitation of the present disclosure. In other embodiments, the length of the dummy teeth 940 can be adjustable. For example, if a depth of the rotor slot 930 is L, a length of the dummy teeth 940 can be 2/5L to 5/5L.

Please refer to FIG. 10. FIG. 10 is a schematic diagram of a rotor 1000 according to a second embodiment of the present disclosure. As shown in FIG. 10, the rotor 1000 may include, but is not limited to, a shaft 1050, a rotor yoke 1010, a plurality of regular teeth 1020, a plurality of rotor slots 1030, and a plurality of dummy teeth 1040. Each of the plurality of rotor slots 1030 includes one slot opening 1031, a bottom wall 1032 adjacent to the rotor yoke 1010 and two side walls 1033A and 1033B adjacent to the slot opening 1031. In this embodiment, the plurality of dummy teeth 1040 is extended from the two side walls 1033A and 1033B of the plurality of rotor slots 1030 to the interior of the rotor slots 1030. In other words, each of the plurality of dummy teeth 1040 is extended from the regular teeth 1020. The dummy teeth 1040 have same material with the regular teeth 1020, and the thermal conductivity of the dummy teeth 1040 (or the regular teeth 1020) is much higher than the equivalent thermal conductivity, which is easy to manufacture.

In this embodiment, there are four dummy teeth 1040 in each rotor slot 1030. In other words, there are two dummy teeth 1040 in each of the side walls 1033A and 1033B of the rotor slot 1030, separating the regular tooth 1020 into three equal parts. However, the number of the dummy teeth 1040 should not be considered as a limitation of the present invention. In other embodiments, the number of the dummy teeth 1040 can be adjustable. For example, if a number of the plurality of rotor slots 1030 is n, a number of the dummy teeth 1040 can be 2n, 4n, 6n, or more. In another embodiment, if a number of the plurality of rotor slots 1030 is n, the number of the dummy teeth 1040 can be 2n, 2n/2, 2n/3, 2n/4, or less. For example, there is only one pair of dummy teeth 1040 in every two adjacent rotor slots 1030 or in every three adjacent rotor slots 1030.

Please refer to FIG. 11. FIG. 11 is a schematic diagram of a rotor 1100 according to a third embodiment of the present disclosure. As shown in FIG. 11, the rotor 1100 may include, but is not limited to, a shaft 1050, a rotor yoke 1010, a plurality of regular teeth 1120, a plurality of rotor slots 1130, and a plurality of dummy teeth 1140. The rotor 1100 shown in FIG. 11 is similar to the rotor 1000 shown in FIG. 10, and the difference between them is that the dummy teeth 1140 and the regular teeth 1120 of the rotor 1100 have different materials. For example, the material of the dummy teeth 1140 is ceramic and the material of the regular teeth 1120 is lamination, the thermal conductivity of ceramic is much higher than the regular teeth 1120 and the equivalent thermal conductivity inside the rotor slot 1130, which can help to conduct heat generated in the rotor slot 1130 more effectively to the regular teeth 1120 and then to the coolant (not shown).

Please note that, in the abovementioned embodiments shown in FIG. 9-FIG. 11, each of the plurality of dummy teeth has a rectangular shape. However, the shape of the dummy teeth should not be a limitation of the present disclosure. In other embodiments, the dummy teeth can be designed to have a trapezoidal shape. The rectangular shape means that the width of the dummy tooth adjacent to the bottom wall is the same as the width of the dummy tooth adjacent to the slot opening. The trapezoidal shape means that the width of the dummy tooth adjacent to the bottom wall is different from (larger than or smaller than) the width of the dummy tooth near the slot opening.

In other embodiments, each of the plurality of dummy teeth may be designed to further include a main part and a plurality of fins (not shown), wherein a centerline of the main part coincides with a symmetry axis of the rotor slot, and the plurality of fins are placed on two sides of the main part. Preferably, the pair of fins and the main part of the dummy tooth are integrally formed. The pair of fins is arranged on two sides of the main part for collecting heat generated in the rotor slot and transferring heat to the main part, such that the heat dissipation capability of the rotor 900 in an electrical machine can be increased. Be noted that, the number of the fins can be adjustable. For example, if a number of the dummy teeth 940 is m, a number of the fins can be 2m, 4m, 6m or more. The design of the fins of the dummy teeth 940 of the rotor 900 is similar to the fins 442/542/543 of the dummy teeth 440/540 of the stator 400/500 shown in FIG. 4 and FIG. 5, and further description is omitted.

Please note that, in the abovementioned embodiments shown in FIG. 9-FIG. 11, the plurality of rotor slots has a first thermal conductivity, the plurality of dummy teeth has a second thermal conductivity, and the second thermal conductivity of the dummy teeth is higher than the first thermal conductivity of the rotor slot.

Please refer to FIG. 12. FIG. 12 is a schematic diagram of an electrical machine 1200 according to an embodiment of the present disclosure. As shown in FIG. 12, the electrical machine 1200 may include, but is not limited to, a housing 1210, a stator 1220, and a rotor 1230. Be noted that, the electrical machine 1200 is a combination of the stator 500 shown in FIG. 5 and the rotor 900 shown in FIG. 9. The housing 1210 is made from aluminum, whose thermal conductivity is 180 w/(mk), much higher than lamination thermal conductivity (30 w/(mk)) of the stator 1220. The housing 1210 further includes a plurality of housing extension 1211 connected to the stator yoke of the stator 1220. There are stator iron losses in the stator 1220 (lamination) and heat conducted from the stator slot, and this embodiment helps to conduct the heat in the stator 1220 to the coolant (not shown). More heat will be conducted from the stator 1220 to the housing 1210, reducing the temperature of the stator 1220 and improving the thermal conditions of the electrical machine 1200.

Moreover, the aforementioned stators and rotors in any one of the embodiments shown in FIG. 1-FIG. 12 can be used separately or combined.

According to one embodiment of the present disclosure, an electrical machine with thermal benefits is provided. The electrical machine includes a first electrical machine component and a second electrical machine component. The first electrical machine component is configured to generate loss and having a first thermal conductivity. The second electrical machine component is disposed adjacent to the first electrical machine component and having a second thermal conductivity. The second thermal conductivity is higher than the first thermal conductivity, wherein heat generated near the first electrical machine component is transferred to the second electrical machine component and dissipated to coolant of the electrical machine by the second electrical machine component, thus making the heat easier to be dissipated to a coolant of the electrical machine.

Compared with the prior thermal technology, the above structures of stators/rotors in the present disclosure have the following advantages. The highest winding temperature is generally located at the center C of the stator/rotor slot, due to high winding losses but low equivalent thermal conductivity inside the stator/rotor slot. The dummy teeth have higher thermal conductivity than the equivalent thermal conductivity inside the stator/rotor slot. Therefore, the dummy teeth can reduce the equivalent thermal resistance inside the stator/rotor slot, and shorten the equivalent thermal path between a hot spot in the stator/rotor slot and coolant largely. Thus, heat generated in the stator/rotor slot is more easily to be dissipated to the coolant, which can improve the thermal condition.

Preferably, the aforesaid dummy teeth are integrally formed with the stator/rotor yoke, which is directly connected to the bottom wall of the stator/rotor slot, so as to simplify the electrical machine component manufacturing process and improve its mechanical strength. As the dummy teeth are the same material with the regular teeth, whose thermal conductivity is much higher than the equivalent thermal conductivity inside the stator/rotor slot, heat generated in the stator slot is easier to be dissipated to the coolant.

Preferably, the dummy teeth start from the middle location of the bottom wall of the stator/rotor slot and its centerline axis coincides with the symmetry axis of the stator/rotor slots, which makes the heat more easily to be transferred to the coolant, as the highest winding temperature is generally located in the center of the stator/rotor slot.

It has been shown that the peak temperature within the stator/rotor slot can be reduced by over 20 degrees with the dummy teeth on one electrical machine, which leads to higher power output, improved efficiency, increased reliability and machine lifetime. Moreover, in a volume production environment, this modification is very low cost and simple to implement as it does not involve any extra materials or manufacturing processes.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than limiting the same. Although the present disclosure has been described in detail with reference to the foregoing embodiments, the technical solutions described in the foregoing embodiments can be modified, or some of the technical features are equally replaced. Those skilled in the art should understand these modifications or replacements are still within the protection of the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Reference in the specification to "one example" or "an example" means that a particular feature, structure, or characteristic described in connection with the example is included in at least an implementation. The appearances of the phrase "in one example" in various places in the specification are not necessarily all referring to the same example. Thus, although examples have been described in language specific to structural features and/or methodological acts, it is to be understood that claimed subject matter may not be limited to the specific features or acts described. Rather, the specific features and acts are disclosed as sample forms of implementing the claimed subject matter.

The above are only preferred examples of the present disclosure is not intended to limit the present disclosure within the spirit and principles of the present disclosure, any changes made, equivalent replacement, or improvement in the protection of the present disclosure should contain within the range.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the meters and bounds of the appended claims.

Claims

Claims: What is claimed is: 1. A stator with thermal benefits, comprising: a stator yoke; a plurality of regular teeth; a plurality of stator slots, wherein the plurality of stator slots and the plurality of regular teeth are aligned in a circle between the stator yoke and a center of the stator, each stator slot is located between two regular teeth, and each of the plurality of stator slots comprises one slot opening, a bottom wall adjacent to the stator yoke and two side walls adjacent to the slot opening; and a plurality of dummy teeth, extended from the bottom wall or the two side walls of the plurality of stator slots; wherein a first width of the stator slot is larger than a second width of the dummy teeth.
2. The stator with thermal benefits of claim 1, wherein each of the plurality of dummy teeth is extended radially inward from the bottom wall of the stator slot to the center of the stator.
3. The stator with thermal benefits of claim 2, wherein a number of the plurality of stator slots is n, and a number of the dummy teeth is n, 3n, 5n, 7n, or more.
4. The stator with thermal benefits of claim 2, wherein a number of the plurality of stator slots is n, and a number of the dummy teeth is n, n/2, n/3, n/4, or less.
5. The stator with thermal benefits of claim 2, wherein each of the plurality of dummy teeth further comprises: a main part, wherein a centerline of the main part coincides with a symmetry axis of the stator slot; and a plurality of fins, placed on two sides of the main part; wherein a number of the dummy teeth is m, and a number of the fins is 2m, 4m, 6m or more.
6. The stator with thermal benefits of claim 1, wherein each of the plurality of dummy teeth is extended from the two side walls of the stator slot to the interior of the stator slot.
7. The stator with thermal benefits of claim 6, wherein a number of the plurality of stator slots is n, and a number of the dummy teeth is 2n, 4n, 6n or more.
8. The stator with thermal benefits of claim 6, wherein each of the plurality of dummy teeth further comprises: a main part, wherein a centerline of the main part coincides with a symmetry axis of the stator slot; and a plurality of fins, placed on two sides of the main part; wherein a number of the dummy teeth is m, and a number of the fins is 2m, 4m, 6m or more.
9. The stator with thermal benefits of claim 1, wherein each of the plurality of dummy teeth comprises a trapezoidal shape or a rectangular shape.
10. The stator with thermal benefits of claim 1, wherein a depth of the stator slot is L, and a length of the dummy teeth is 2/5L to 5/SL.
11. The stator with thermal benefits of claim 1, wherein the plurality of stator slots has a first thermal conductivity, the plurality of dummy teeth has a second thermal conductivity, and the second thermal conductivity of the dummy teeth is higher than the first thermal conductivity of the stator slot.
12. A rotor with thermal benefits, comprising: a shaft, located in a center of the rotor; a rotor yoke, located around the rotor shaft; a plurality of regular teeth; a plurality of rotor slots, wherein the plurality of rotor slots and the plurality of regular teeth are aligned in a circle around the rotor yoke, each rotor slot is located between two regular teeth, and each of the plurality of rotor slots comprises one slot opening, a bottom wall adjacent to the rotor yoke and two side walls adjacent to the slot opening; and a plurality of dummy teeth, extended from the bottom wall or the two side walls of the plurality of rotor slots; wherein a first width of the rotor slot is larger than a second width of the dummy teeth.
13. The rotor with thermal benefits of claim 12, wherein each of the plurality of dummy teeth is extended radially outward from the bottom wall of the rotor slot to the slot opening of the rotor slot.
14. The rotor with thermal benefits of claim 13, wherein a number of the plurality of rotor slots is n, and a number of the dummy teeth is n, 3n, 5n, 7n, or more.
15. The rotor with thermal benefits of claim 13, wherein a number of the plurality of rotor slots is n, and a number of the dummy teeth is n, n/2, n/3, n/4, or less.
16. The rotor with thermal benefits of claim 13, wherein each of the plurality of dummy teeth further comprising: a main part, wherein a centerline of the main part coincides with a symmetry line of the rotor slot; and a plurality of fins, placed on two sides of the main part; wherein a number of the dummy teeth is m, and a number of the fins is 2m, 4m, 6m or more.
17. The rotor with thermal benefits of claim 12, wherein each of the plurality of dummy teeth is extended from the two side walls of the rotor slot to the interior of the rotor slot.
18. The rotor with thermal benefits of claim 17, wherein a number of the plurality of rotor slots is n, and a number of the dummy teeth is 2n, 4n, 6n or more.
19. The rotor with thermal benefits of claim 17, wherein each of the plurality of dummy teeth further comprising: a main part, wherein a centerline of the main part coincides with a symmetry line of the rotor slot; and a plurality of fins, placed on two sides of the main part; wherein a number of the dummy teeth is m, and a number of the fins is 2m, 4m, 6m or more.
20. The rotor with thermal benefits of claim 12, wherein each of the plurality of dummy teeth comprises a trapezoidal shape or a rectangular shape.
21. The rotor with thermal benefits of claim 12, wherein a depth of the stator slot is L, and a length of the dummy teeth is 2/5L to 5/5L.
22. The rotor with thermal benefits of claim 12, wherein the plurality of rotor slots has a first thermal conductivity, the plurality of dummy teeth has a second thermal conductivity, and the second thermal conductivity of the dummy teeth is higher than the first thermal conductivity of the rotor slot.
23. An electrical machine with thermal benefits, which includes any of the stators claimed from claim 1 to claim 11, or any of the rotors claimed from claim 12 to claim 22, or the combination of the said stators and the said rotors.
24. An electrical machine with thermal benefits, comprising: a first electrical machine component, configured to generate loss and having a first thermal conductivity; and a second electrical machine component, disposed adjacent to the first electrical machine component and having a second thermal conductivity; wherein the second thermal conductivity is higher than the first thermal conductivity; wherein heat generated near the first electrical machine component is transferred to the second electrical machine component, and is dissipated to coolant of the electrical machine by the second electrical machine component.
25. The electrical machine with thermal benefits of claim 24, wherein the first electrical machine component is a stator or a rotor.