A stator

Abstract

The present invention provides a stator (1), comprising a lamination stack (10), the lamination stack (10) having a plurality of segments (20), the segments (20) being connected to each other via corresponding folding joints (30), wherein at least one folding joint (30) is radially arranged on the inner side of a virtual circumference (27) corresponding to the maximum radius (R2) of the lamination stack (10). The stator (1) further comprises a plurality of insulators (40), wherein at least one insulator (40) comprises an end portion (48, 49) axially extending from the lamination stack (10), and a radial space is provided between the outer circumference of the end portion (48, 49) and the outer circumference of the lamination stack (10).

Description

Technical Field

[0001] The present invention relates to a stator and a lamination stack, in particular to a lamination stack constituting a part of a stator of a brushless DC motor. The present invention also relates to an electric motor having the stator. Background Art

[0002] In a brushless DC motor, the stator may be manufactured from a lamination stack having a plurality of windings. When forming part of the motor, the lamination stack has a cylindrical shape.

[0003] However, the stator can be manufactured by arranging the lamination stack in a linear shape, thereby winding and placing the windings on the lamination stack. The lamination stack is then folded into a cylindrical shape, and the ends of the lamination stack are welded together.

[0004] Stator performance depends on the arrangement of the windings relative to the lamination stack. Therefore, special attention needs to be paid to the positioning of the windings to optimize the motor characteristics. However, it is also important to reduce the size of the motor, especially to minimize the size of a particular motor without reducing the performance of the motor. Summary of the invention

[0005] The object of the present invention is to alleviate the above disadvantages and to provide an improved lamination stack and an improved stator. In particular, it is an object of the present invention to provide an electric motor which is more space-saving.

[0006] According to a first aspect, a stator is provided. The stator comprises a lamination stack, the lamination stack having a plurality of segments, the segments being connected to each other by corresponding folding joints, wherein at least one folding joint is radially arranged on the inner side of a virtual circumference corresponding to the maximum radius of the lamination stack. The stator further comprises a plurality of insulators, wherein at least one insulator comprises an end portion extending axially from the lamination stack, and a radial space is provided between the outer circumference of the end portion and the outer circumference of the lamination stack.

[0007] According to a second aspect, a stator is provided. The stator comprises a lamination stack having a plurality of segments connected to each other by folding joints, wherein at least one folding joint is provided on a portion of the segment having a specific thickness extending between a radius (R1) of an inner surface and a radius (R2) of an outer surface. Each folding joint is provided at a radial position (R3) between (R1+0.3*(R2-R1)) and (R1+0.9*(R2-R1)). The stator further comprises a plurality of insulators, wherein at least one insulator comprises an end portion extending axially from the lamination stack and providing a radial space between an outer circumference of the end portion and an outer circumference of the lamination stack.

[0008] In one embodiment, each fold joint is arranged at a radial position between (R1+0.5*(R2-R1)) and (R1+0.7*(R2-R1)).

[0009] By arranging the folded joint at a smaller radius, a higher tension will in fact be provided for the phase winding arranged at the end of an insulator, as described below.

[0010] In the following, some preferred embodiments will be briefly discussed - these embodiments are equally applicable to the first aspect and the second aspect.

[0011] The stator may further include a plurality of windings, wherein at least one phase winding is arranged in the radial space between the outer circumference of the rear end portion and the outer circumference of the lamination stack. Since the phase winding is arranged radially inside the outer circumference of the lamination stack, the size of the motor can be reduced.

[0012] The stator may further include a lead frame, wherein a cylindrical wall of the lead frame may be disposed in the radial space between an outer circumference of the rear end portion and an outer circumference of the lamination stack.

[0013] Preferably, the cylindrical wall of the lead frame is arranged radially outside the at least one phase winding. This makes the stator more compact, thereby also making the motor more compact.

[0014] The stator may further include a front cover disposed at the front end of the stator. Preferably, a radial seal of the front cover is disposed in the radial space between the outer circumference of the front end and the outer circumference of the lamination stack. This provides an efficient and compact seal for a motor housing.

[0015] At least one insulator is formed by a rear insulator component and a front insulator component. This is not only beneficial for the manufacture of the insulator, but also for mounting the winding on the lamination stack.

[0016] The radial position of at least one (preferably each) folding joint coincides with a radius of the outer circumference of the rear end portion, in particular at the axial end of the rear end portion.

[0017] According to a third aspect, an electric motor is provided, wherein the electric motor comprises a stator according to any one of the first or second aspects.

[0018] According to another aspect, a lamination stack for a stator is provided. The lamination stack includes a plurality of segments connected to each other by folded joints, wherein the folded joints are arranged radially inside a virtual circle corresponding to a maximum radius of the lamination stack.

[0019] According to another aspect, a lamination stack for a stator is provided, the lamination stack comprising a plurality of segments connected to each other by folding joints, wherein each folding joint is disposed on a portion of the segment having a specific thickness extending between an inner surface radius and an outer surface radius, wherein each folding joint is disposed at a radial position between (R1+0.3*(R2-R1)) and (R1+0.9*(R2-R1)).

[0020] Each folding joint may be arranged at a radial position between (R1+0.5*(R2-R1)) and (R1+0.7*(R2-R1)). BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be described in more detail below with reference to the accompanying drawings, in which

[0022] Figure 1 is an isometric view of a stator according to an embodiment;

[0023] Figure 2 yes Figure 1 An exploded isometric view of a stator as described in claim 1, comprising a lead frame and a rotor;

[0024] Figure 3 yes Figure 1 and Figure 2 An exploded view of the stator is shown;

[0025] Figure 4 is an isometric view of a lamination stack according to one embodiment;

[0026] Figure 5 yes Figure 4 A side view of the lamination stack is shown;

[0027] Figure 6 yes Figure 5 An enlarged view of a section of a lamination stack is shown;

[0028] Figure 7 yes Figure 1 a side view of the stator shown; and

[0029] Figure 8 Yes Figure 1 A cross-sectional view of the various parts of the electric motor showing the stator. DETAILED DESCRIPTION

[0030] Figure 1A stator 1 is shown. The stator 1 is intended to form part of a brushless DC motor, and comprises a lamination stack 10 forming a cylindrical shape. A plurality of insulators 40 are distributed on the inner periphery of the lamination stack 10, and each insulator 40 carries a coil or winding 50. In the example shown, there are nine insulators 40 and therefore nine windings 50.

[0031] Figure 2 , the installation of the stator 1 is shown. A rotor housing 60 is arranged inside the stator 1, i.e. radially inside the insulator 40 and the corresponding coil 50. A lead frame 70 is arranged on the rear side of the stator 1. The lead frame 70 forms an axial end of the motor and is provided with a plurality of metal structures and electrical components 72 to allow the winding 50 to be connected to an external power source (not shown).

[0032] Figure 3 The details of the stator 1 are further shown in detail. Specifically, each insulator 40 is formed by a front insulator component 42 and a rear insulator component 44. The front insulator component 42 is pushed into the lamination stack 10 from the front side, and the rear insulator component 44 is pushed into the lamination stack 10 from the rear side. Figure 3 As shown, each front insulator member 42 has two legs 46a, 46b extending from a front end part 48, and each rear insulator member 44 has two legs 47a, 47b extending from a rear end part 49. Each leg 46a-b, 47a-b is V-shaped to accommodate the winding 50. For each insulator member 42, 44, the legs 46a-b, 47a-b are opposite to each other so that the openings of the V-shaped members are opposite. This means that each winding 50 will be wound around the first legs 46a, 47a of two aligned insulator members 42, 44 and the second legs 46b, 47b of two adjacent aligned insulator members 42, 44.

[0033] like Figure 3 As further shown in FIG. 4 , the winding 50 terminates in a plurality of phase windings 52 a - d that extend parallel to one another along the periphery of the rear end portion 49 of the rear insulator member 44 .

[0034] The lamination stack 10 is formed of a plurality of linear metal sheet sheets 10a, such as Figure 4 The number of sheets 10a will depend on the motor performance and other design criteria; however, for a motor suitable for vehicle and automotive applications, the typical number of sheets 10a is in the range of 10-100, such as in the range of 20-80, preferably in the range of 40-60.

[0035] Each sheet 10a, and therefore the entire lamination stack 10, forms a linear array of a plurality of continuous T-shaped segments 20. Figure 5 As shown, each segment 20 is connected to an adjacent segment 20 by a folding joint 30. For each T-shaped segment 20, a stem or tee 22 projects radially inwardly (with reference to the radial direction when the lamination stack 10 is folded into a cylindrical shape) from a yoke 24 and is used to mount the insulator members 42, 44 to the lamination stack 10.

[0036] like Figure 4-5 As shown, during the manufacturing process, the lamination stack 10 is formed into a linear shape as shown. The insulator 40 and the winding 50 are mounted to the linear lamination stack before the entire assembly is folded into a cylindrical shape. In these figures, the lamination stack 10 is shown in a manufacturing step before the insulating member 40 and the corresponding winding 50 are assembled.

[0037] like Figure 6 2, a segment 20 of the lamination stack 10 is further shown in detail. The segment 20 has a radial outer surface 25 and a radial inner surface 26 defined by the radial thickness of the yoke 24. The inner surface 26 and the outer surface 25 intersect at a fold joint 30; at the fold joint 30, the radial distance between the inner surface 26 and the outer surface 25 is the smallest.

[0038] To improve the winding of the coil / winding 50 when assembled into the cylindrical shape, the folded joint 30 should be arranged radially inwardly inside a virtual circumference 27 corresponding to the maximum radius of the lamination stack 10 .

[0039] This means that the folded joint 30 between two adjacent segments 20 of the lamination stack 10 forms a depression 28 at the outer surface 25 and a circumferentially aligned depression 29 at the inner surface 26, preferably in an axial extension corresponding to the entire width of the lamination stack 10. The outer depression 28 is U-shaped, while the inner depression 29 is in the shape of a keyhole.

[0040] Preferably, the folding joint 30 is arranged at a portion of the segment 20 having a specific thickness extending between the radius R1 of the inner surface 26 and the radius R2 of the outer surface 25 (rather than the virtual circumference 27); then, preferably, the folding joint 30 is arranged at a radial position R3, and the radial position R3 is between (R1+0.3*(R2-R1)) and (R1+0.9*(R2-R1)), more preferably, between (R1+0.5*(R2-R1)) and (R1+0.7*(R2-R1)).

[0041] By arranging the folding joint 30 radially inwardly of the virtual circumference 27, the tension of the phase windings 52a-d provided when the entire stator 1 is folded into a cylindrical shape is increased. As previously described, the winding 50 is terminated in a plurality of phase windings 52a-d, and the phase windings 52a-d extend parallel to each other along the outer circumference of the rear end part 49 of the rear insulator member 44. By arranging the folding joint 30 and the phase windings 52a-d at the same (or substantially the same) radius, the slack in the phase windings 52a-d is minimized, thereby improving the robustness of the entire motor when the positions of the phase windings 52a-d are fixed.

[0042] The side view of the stator 1 is as follows Figure 7 As shown. It can be clearly seen from the figure that the lamination stack 10 is folded into a cylindrical shape; therefore, the internal recess 29 is compressed so that adjacent yokes 24 meet in the area of ​​the internal recess 29. Alternatively, adjacent yokes 24 are arranged at least very close to each other. The outer periphery of the insulator 40, in particular the outer periphery of the rear end 49 of the rear insulator member 44, is arranged with a radius R4. Preferably, the radius R4 is measured at the axial end of the rear insulator member 44. It should be noted that since the rear end member 49 is substantially planar, the radius R4 is not constant. However, the radius R2 (which is constant, especially when indicating the radius of the virtual circle 27) should always be greater than the radius R4, preferably always greater than 1 mm, so that the difference between the radius R2 and the radius R4 is between 1 and 2 mm. In some embodiments, the difference between radius R2 and radius R4 may depend on the wire diameter; if a wire diameter is 0.9 mm, the difference between radius R2 and radius R4 may be between 1.17 and 2.25 mm, i.e., between 1.3 and 2.5 times the wire diameter.

[0043] like Figure 8 As shown, preferably, the radial space provided between the outer circumference of the rear end portion 49 and the outer circumference of the lamination stack 10 is used to accommodate the phase lines 52a-d. Figure 8 Components of an electric motor 100 including the above-described stator 1 are shown. However, the inventors unexpectedly realized that the same radial space can also be used to connect the lead frame 70. Figure 8 (as well as Figure 2 ), it can be seen how the lead frame 70 has a cylindrical side wall 74 extending from the outer periphery of the circular lead frame 70 toward the stator 1. The cylindrical side wall 74 is inserted onto the insulator 40 so that the side wall 74 fits into the radial space between the outer periphery of the back end component 49 and the outer periphery of the lamination stack 10, and the cylindrical side wall 74 also has one or more leads 72.

[0044] Additionally, a similar radial space is provided at the front, between the outer perimeter of the front end 48 and the outer perimeter of the lamination stack 10. Although the radial space is not used to accommodate phase conductors 52a-d, it is configured to allow a radial seal 80 to be formed between a cylindrical housing 82 and a front motor cover 84.

[0045] The combination of the position of the folded joint 30 at the reduced radius R3 and the radial space provided between the outer circumference of the end portions 48, 49 and the outer circumference of the lamination stack machine 10 is therefore very advantageous, since it not only allows an extremely space-saving connection of the lead frame 70 to the stator 1, but also allows an extremely space-saving radial seal to be installed between the front cover 84 and the motor housing 82.

Claims

1. A stator (1), characterized in that: The invention comprises a lamination stack (10), the lamination stack (10) having a plurality of segments (20), the segments (20) being connected to each other via corresponding folding joints (30), wherein at least one folding joint (30) is radially arranged on the inner side of a virtual circumference (27) corresponding to the maximum radius of the lamination stack (10), wherein the stator (1) further comprises a plurality of insulators (40), wherein at least one insulator (40) comprises a rear end portion (49) extending axially from the lamination stack (10), and a radial space is provided between the outer circumference of the rear end portion (49) and the outer circumference of the lamination stack (10), wherein at least one phase winding (52a-d) is arranged in the radial space between the outer circumference of the rear end portion and the outer circumference of the lamination stack, and wherein the folding joint and the at least one phase winding are arranged at the same radius.

2. The stator according to claim 1, characterized in that: Also included are a plurality of windings (50).

3. The stator according to claim 1, characterized in that: It also includes a lead frame (70), wherein a cylindrical wall (74) of the lead frame (70) is arranged in the radial space between the outer circumference of the rear end portion (49) and the outer circumference of the lamination stack (10).

4. The stator according to claim 3, characterized in that: The cylindrical wall (74) of the lead frame (70) is arranged radially outside the at least one phase winding (52a-d).

5. The stator according to claim 1, characterized in that: It also includes a front cover (84) arranged at a front end portion (48) of the stator (1).

6. The stator according to claim 5, characterized in that: A radial seal (80) of the front cover (84) is disposed in the radial space between the outer circumference of the front end portion (48) and the outer circumference of the lamination stack (10).

7. The stator according to claim 1, characterized in that: The at least one insulator (40) is formed from a rear insulator member (42) and a front insulator member (44).

8. A stator (1), characterized in that: The invention relates to a lamination stack (10), wherein the lamination stack (10) has a plurality of segments (20) connected to each other by folding joints (30), wherein at least one folding joint (30) is arranged on a portion of the segment (20) having a specific thickness extending between a radius R1 of an inner surface (26) and a radius R2 of an outer surface (25), wherein each folding joint (30) is arranged at a radial position (R3) between (R1+0.3*(R2-R1)) and (R1+0.9*(R2-R1)), The stator (1) further comprises a plurality of insulators (40), wherein at least one insulator (40) comprises a rear end portion (49) axially extending from the lamination stack (10) and providing a radial space between an outer circumference of the rear end portion (49) and an outer circumference of the lamination stack (10), wherein at least one phase winding (52a-d) is arranged in the radial space between the outer circumference of the rear end portion and the outer circumference of the lamination stack, and wherein the folded joint and the at least one phase winding are arranged at the same radius.

9. The stator according to claim 8, characterized in that: Each folding joint (30) is arranged at a radial position (R3) between (R1+0.5*(R2-R1)) and (R1+0.7*(R2-R1)).

10. The stator according to any one of claims 8 to 9, characterized in that: Also included are a plurality of windings (50).

11. The stator according to claim 8, characterized in that The radial position of at least one folding joint (30) is consistent with the radius R4 of the outer circumference of the rear end portion (49).

12. The stator according to claim 8, characterized in that It also includes a lead frame (70), wherein a cylindrical wall (74) of the lead frame (70) is arranged in the radial space between the outer circumference of the rear end portion (49) and the outer circumference of the lamination stack (10).

13. The stator according to claim 12, characterized in that: The cylindrical wall (74) of the lead frame (70) is arranged radially outside the at least one phase winding (52a-d).

14. The stator according to claim 8, characterized in that It also includes a front cover (84) arranged at a front end portion (48) of the stator (1).

15. The stator according to claim 14, characterized in that A radial seal (80) of the front cover (84) is disposed in the radial space between the outer circumference of the front end portion (48) and the outer circumference of the lamination stack (10).

16. The stator according to claim 8, characterized in that The at least one insulator (40) is formed from a rear insulator member (42) and a front insulator member (44).

17. An electric motor (100), characterized in that: Comprising a stator (1) according to any one of the preceding claims.

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