Waterproof structure for an electric motor

Abstract

Waterproof structure for an electric motor (1) in which an embedding component (3) of a stator (2) is cast into a molding resin (4), a sealing element (5) is arranged in an end region (20) of the stator (2) which includes a connection point (23) between the embedding component (3) and the molding resin (4), and the sealing element (5) is attached to the end region (20) by means of an end flange (6), wherein the sealing element (5) comprises: a first sealing part (55) which is arranged further on one side of the embedding component (3) than the connection point (23) and seals one end of the embedding component (3); a second sealing part (56) which is arranged further on one side of the molding resin (4) than the connection point (23) and seals one end of the molding resin (4); and a connecting part (57) that is separated from the ends of both the embedding component (3) and the molding resin (4) and connects the first sealing part (55) and the second sealing part (56).

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to a waterproof structure for an electric motor in which embedding components of a stator are cast in molding resin. Related technology

[0002] Traditionally, in stators of this type of electric motor, a gap forms at the interface where the encapsulation component and the molding resin meet, due to the temperature change after molding and the difference between their linear expansion coefficients. A sealing treatment can be applied to this gap.

[0003] Therefore, as in Fig. Figure 10 shows an attempt to perform a sealing treatment on a gap such as the one described above using an O-ring 105 (see also Patent Specification 1). However, it is difficult to position its sealing point at the interface where the embedding component 103 and the molding resin 104 meet, and the O-ring 105 cannot achieve a seal if the position between the sealing point and the interface shifts.

[0004] To remedy this, as in Fig. Figure 11 shows an attempt to perform a sealing treatment on a gap such as the one described above using a seal 205 with a plate-like (rectangular) cross-section. The plate-like seal 205 can, however, improve the positional displacement between the sealing point and the interface; while, on the other hand, the surface pressure does not increase compared to the O-ring 105, and therefore the sealing capacity is low and a complete seal may be impossible.

[0005] Patent specification 1: Unexamined Japanese patent application, Publication No. JP 2010 - 226 907 A

[0006] DE 10 2014 106 361 A1 describes a stator of an electric motor in which a resin mold section is formed by injection molding into an inner circumferential section and an outer circumferential section, wherein a separating element is provided at the axial end section of the stator for separating the inner circumferential section from the outer circumferential section. Resin injected from the axial end section flows in a forked passage into the inner circumferential section and the outer circumferential section. The separating element can be provided with a resin passage that allows resin to flow from the axial end section of the stator to the outer circumferential section.

[0007] JP 2001 - 245 453 A describes a motor consisting of a cylindrical yoke with a base that accommodates a rotor, an end plate that closes an opening in the yoke with a fastener elastically fitted to the inner circumference of the yoke, and a sealing material arranged on the outer circumference of the end plate at the flange on the opening side of the yoke. The sealing material seals the inside of the outer device between the flange and the end face of the outer device and has an annular sealing surface on which two annular projecting parts extend along the sealing surface.

[0008] WITTEL, Herbert [et al.]: Roloff / Matek - Machine Elements - Standardization, Calculation, Design, 22nd revised and expanded edition Wiesbaden: Springer 2015, pp. 698-717, ISBN 978-3-658-09081-4 describes seals in which the sealing material is protected by a metallic shell or metallic inserts provide support. SUMMARY OF THE INVENTION

[0009] However, in the sealing treatment using the O-ring 105 or the plate-like seal 205, due to the insufficient sealing in both cases, the sealing was reinforced by soaking in a sealant 150, 250 to fill the gap at the interface, as described in the Fig. 10 and Fig. 11 were shown. This required corresponding working time.

[0010] It is an object of the present invention to provide a waterproof structure for an electric motor by which the interface where the embedding component of the stator and the molding resin meet can be sealed more reliably without requiring time for soaking in a sealant.

[0011] According to a first aspect of the present invention, in a waterproof structure for an electric motor (for example, the electric motor 1 described below), in which an embedding component (for example, the embedding component 3 described below) of a stator (for example, the stator 2 described below) is cast into a molding resin (for example, the molding resin 4 described below), a sealing element (for example, the sealing element 5 described below) is arranged in an end region (for example, the end region 20 described below) of the stator, which comprises a connection point (for example, the connection point 23 described below) between the embedding component and the molding resin, and the sealing element is attached to the end region by means of an end flange (for example, the end flange 6 described below), wherein the sealing element comprises: a first sealing part (for example, the first seal 55 described below),a first sealing part (for example, the second sealing part 56 described later) which is positioned further on one side of the embedding component than the joint and seals one end of the embedding component; a second sealing part (for example, the second sealing part 56 described later) which is positioned further on one side of the molding resin than the joint and seals one end of the molding resin; and a connecting part (for example, the connecting part 57 described later) which is provided separately from the ends of both the embedding component and the molding resin and connects the first sealing part and the second sealing part.

[0012] According to a second aspect of the present invention, the sealing element in the waterproof structure for an electric motor described in connection with the first aspect can have a rigid body inside it.

[0013] According to the present invention, it is possible to seal an interface more reliably where an embedding component of a stator and a molding resin meet, without having to spend time softening it in a sealant. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an end view showing a stator of an electric motor according to a first embodiment; Fig. Figure 2 is a side sectional view of the stator according to Fig. 1; Fig. Figure 3 is a side sectional view of an embedded component of the stator in Fig. 2; Fig. 4 is a view showing a sealing element of the stator according to Fig. 1 shows; Fig. Figure 5 is an enlarged view showing a cross-section along line AA according to Fig. 1 shows; Fig. 6 is an enlarged view showing a main part according to Fig. 5 shows; Fig. Figure 7 is a view showing a sealing element according to a second embodiment; Fig. Figure 8 is an enlarged view showing a cross-section along line BB according to Fig. 7 shows; Fig. Figure 9 is an enlarged view showing a cross-section along line CC according to Fig. 7 shows; Fig. Figure 10 is a sectional view showing an example of a conventional stator; and Fig. Figure 11 is a sectional view showing another example of a conventional stator. DETAILED DESCRIPTION OF THE INVENTION

[0014] The following describes embodiments of the present invention with reference to the drawings. Fig. Figure 1 is an end view showing a stator of an electric motor according to a first embodiment, omitting the representation of an end flange. Fig. Figure 2 is a side sectional view of the stator. Fig. Figure 3 is a side sectional view of an embedding component before it is cast in molding resin. Fig. Figure 4 is a view showing a sealing element. Fig. Figure 5 is an enlarged view showing a cross-section along line AA according to Fig. 1 shows. Fig. 6 is an enlarged view showing the main part according to Fig. 5 shows.

[0015] As in the Fig. As shown in Figures 1 to 6, the stator 2 of the electric motor 1 comprises an encapsulation component 3, a mold resin 4, a sealing element 5, an end flange 6, and screws 7. As shown in Fig. As shown in Figure 3, the embedded component 3 comprises a housing 31, windings 32, and a power connection 33. The housing 31 is in the shape of the one shown in Figure 3. Fig. The stator 2 shown in Figure 1 is formed. The windings 32 are wound around a predetermined position of the housing 31 and are held there. The power terminal 33 is mounted at a predetermined position of the housing 31. The power terminal 33 is electrically connected to the windings 32.

[0016] The molding resin 4 forms the outer surface of the stator 2 by shaping the edge region of the embedding component 3. For this reason, an end region 20, which includes a jointing element (an interface) between the embedding component 3 and the molding resin 4, is formed in the axial direction at one end of the stator 2. More precisely, as shown in Fig. As shown in Figure 1, the end region 20 is formed by a circular region 21, which corresponds approximately to the diameter of the stator 2, and four mounting regions 22, which extend, for example, outwards from the circular region 21.

[0017] The sealing element 5 is arranged at the end region 20 of the stator 2. More precisely, as shown in Fig. Figure 4 shows that the sealing element 5 is designed in one piece by a circular sealing part 51 for arrangement in the circular area 21 and four sealing mounting parts 52, which extend, for example, outwards from the circular sealing part 51. The sealing element 5 is preferably made of an elastic body. A screw through-hole 53 is provided for the sealing mounting part 52, through which the screw 7 is passed.

[0018] As in the Fig. 5 and Fig. As shown in Figure 6, the sealing assembly part 52 of the sealing element 5 comprises a first sealing part 55, a second sealing part 56, and a connecting part 57. The first sealing part 55 is located further on one side of the embedding component 3 (in particular the housing 31) than the connection point 23 (see Figure 6). Fig. 6) is arranged and seals one end of the embedding component 3 (of the housing 31). The second sealing part 56 is arranged further on one side of the molding resin 4 than the connection point 23 and seals the end of the molding resin 4. The connecting part 57 is provided separately from the ends of both the embedding component 3 (of the housing 31) and the molding resin 4 and connects the first sealing part 55 and the second sealing part 56.

[0019] The end flange 6 covers the end region 20 of the stator 2 and is mounted to the mounting component 3 by means of the screws 7. More precisely, as shown in the Fig. 1 and Fig. 5 shown, in the four mounting areas 22 of the end area 20 of the stator 2 threaded bores 311 (see Fig. 5) provided in the housing 31 of the embedding component 3. A screw through-hole 61 is provided in the end flange 6 (see Fig. 5) provided, through which the screw 7 is passed.

[0020] Then the circular sealing part 51 of the sealing element 5 is arranged in the circular area 21 of the stator 2, the four sealing mounting parts 52 of the sealing element 5 are arranged in the four mounting areas 22 of the stator 2, the end flange 6 is positioned so that it covers the sealing element 5, and the screws 7 pass through the four screw through holes 61 of the end flange 6 and the screw through holes 53 of the four sealing mounting parts 52 of the sealing element 5, and then the screw is tightened in the threaded bore 311 of the housing 31. When everything is carried out in this way, the circular sealing part 51 of the sealing element 5 is attached to the circular area 21 of the stator 2, and the four sealing mounting parts 42 of the sealing element 5 are attached to the four mounting areas 22 of the stator 2.

[0021] Simultaneously, in the mounting area 22 of the stator 2, the first sealing part 55 of the sealing mounting part 52 of the sealing element 5 is positioned further towards the housing 31 than the connection point 23 and seals the end of the housing 31. The second sealing part 56 of the sealing mounting part 52 of the sealing element 5 is positioned further towards the mold resin 4 than the connection point 23 and seals the end of the mold resin 4. The connecting part 57 of the sealing mounting part 52 of the sealing element 5 is located at a position slightly offset from the connection point 23. This seals the connection point 23 within a closed space 58, which is surrounded by the first sealing part 55, the second sealing part 56 and the connecting part 57 of the sealing element 5, the end face of the housing 31 and the end face of the molding resin 4, as shown in Fig. 6 shown.

[0022] In the manner described above, according to the present embodiment, the joint 23 is sealed within the enclosed space 58 surrounded by the first sealing part 55, the second sealing part 56, and the connecting part 57 of the sealing element 5, the end face of the housing 31, and the end face of the molding resin 4. Therefore, there is no cause for concern regarding a reduction in sealing capacity due to a gap at the joint 23, even if a gap forms at the joint 23 due to the difference between the linear expansion coefficient of the housing 31 of the embedding component 3 and the linear expansion coefficient of the molding resin 4 during a temperature change. Consequently, impregnation with a sealant to fill the gap at the joint 23 is unnecessary, and no working time is required for impregnation with sealant.

[0023] The foregoing explanation of the sealing assembly part 52 of the sealing element 5 with reference to the Fig. 5 and Fig. Section 6 applies essentially analogously to the circular sealing part 51 of the sealing element 5. For this reason, redundant explanations regarding the circular sealing part 51 of the sealing element 5 are omitted.

[0024] Fig. Figure 7 is a view showing a sealing element 5A according to a second embodiment. Fig. Figure 8 is an enlarged view showing a cross-section along line BB in Fig. 7 shows. Fig. Figure 9 is an enlarged view showing a cross-section along line CC in Fig. 7 shows. In the Fig. Sections 7 to 9 are assigned reference numerals similar to those of the sealing element 5 according to the first embodiment, where an ‘A’ is appended to the reference numeral used for the sealing element 5 according to the first embodiment, and redundant explanations are omitted.

[0025] As in the Fig. As shown in Figures 7 to 9, the sealing element 5A has a rigid body 50 inside. More precisely, the rigid body 50 is inserted into the interior of the sealing element 5A. This sealing element 5A exhibits rigidity compared to the sealing element 5 according to the first embodiment. For this reason, this sealing element 5A is characterized by its ease of handling during installation at the end region 20 of the stator 2 and can contribute to automation.

[0026] Although embodiments of the present invention have been explained above, the present invention may not be limited to the embodiments described above, and modifications and improvements within a scope that allows the objectives of the present invention to be achieved are also included in the present invention. Furthermore, the results described in connection with the present embodiments are merely a list of the most preferred results obtained by the present invention, and the results of the present invention may not be limited to those described in connection with the present embodiments. EXPLANATION OF THE REFERENCE SYMBOLS 1 electric motor 2 Stator 20 End range 23 Jointing part 3 Embedded component 4. Molding resin 5 Sealing element 55 first sealing part 56 second sealing part 57 Connecting part 6 End flange

Claims

Waterproof structure for an electric motor (1) in which an embedding component (3) of a stator (2) is cast into a molding resin (4), a sealing element (5) is arranged in an end region (20) of the stator (2) which includes a connection point (23) between the embedding component (3) and the molding resin (4), and the sealing element (5) is attached to the end region (20) by means of an end flange (6), wherein the sealing element (5) comprises: a first sealing part (55) which is arranged further on one side of the embedding component (3) than the connection point (23) and seals one end of the embedding component (3); a second sealing part (56) which is arranged further on one side of the molding resin (4) than the connection point (23) and seals one end of the molding resin (4); and a connecting part (57) that is separated from the ends of both the embedding component (3) and the molding resin (4) and connects the first sealing part (55) and the second sealing part (56). Waterproof structure of the electric motor (1) according to claim 1, wherein the sealing element (5) comprises a rigid body (50) inside it.

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