Axial sealing structure and electric motor housing comprising same

Abstract

The present invention relates to an axial sealing structure and an electric motor housing comprising same. The axial sealing structure comprises a sealing groove that is formed on a surface of a first component and a rectangular sealing ring that is fitted in the sealing groove, the rectangular sealing ring being squeezed between a second component that is arranged opposite the first component and a bottom wall of the sealing groove, to seal a gap between the first component and the second component. The rectangular sealing ring that has been fitted is provided with multiple support part sections that are spaced apart from each other on a circumference of the rectangular sealing ring, each support part section abutting two sidewalls of the sealing groove, a widthwise compression rate of the rectangular sealing ring at each support part section being set to be above a preset lower limit value, so that the rectangular sealing ring, at an operating pressure thereof, does not overturn in the sealing groove.

Description

DescriptionAxial sealing structure and electric motor housing comprising sameTechnical Field

[0001] The present invention relates to the technical field of device sealing, and more specifically relates to an axial sealing (also called “end face sealing”) structure with a rectangular sealing ring, and an electric motor housing that uses this type of axial sealing structure.Background Art

[0002] A rectangular sealing ring is a sealing member with a rectangular cross section, and is widely used in machinery or devices of various industries, such as transport, chemical engineering and food products, due to advantages thereof, such as good operating stability, anti-aging and sealing performance, and is often used for preventing leakage of liquid and gas media under conditions in which mechanical components are static, and is also able to act, in certain situations, as a dynamic sealing element for an axial reciprocating motion and a low-speed rotating motion.

[0003] For example, with the daily development of electric vehicles, usage requirements and technical requirements for electric motors continuously increase. In order to perform good heat dissipation and cooling on electric motors with gradually increasing power, a passage for cooling liquid to circulate and flow through is provided in the electric motor housing, and these cooling liquid passages often extend across gaps between various component portions of the electric motor housing that are mutually mounted together; hence, it is necessary to seal such gaps to prevent leakage of the cooling liquid.

[0004] In practice, a rectangular sealing ring is already provided around the cooling liquid passage between opposite end faces of two adjoining component portions of an electric motor housing to perform sealing. However, it is known that leakage of cooling liquid still occurs between the abovementioned opposite end faces of the electric motor housing during the operation of the electric motor.Summary of the Invention

[0005] An object of the present invention lies in solving the abovementioned problem and / or other defects in the prior art.

[0006] Having devotedly researched factors such as design, assembly and usage environment of an electric motor housing and a rectangular sealing ring, the inventor ultimately discovered that the abovementioned leakage of cooling liquid originates in the rectangular sealing ring. This discovery was unexpected: although there is no specified standard for the design of a rectangular sealing ring, it normally suffices to consult a design standard for an O-shaped sealing ring to investigate a heightwise compression rate and a cross-sectional fill rate, and as long as a rectangular sealing ring product satisfies the specified standards of these two parameters, it is generally able to meet performance requirements; however, although the abovementioned existing rectangular sealing ring satisfies design requirements for heightwise compression rate and cross-sectional fill rate, leakage still occurs. As known by a person skilled in the art, “heightwise compression rate” refers to a ratio of a difference between an original height of a rectangular sealing ring and a height thereof after being squeezed and fitted into a corresponding sealing groove (normally the cross-section thereof is also rectangular) to the original height thereof, and “cross-sectional fill rate” refers to a ratio of a cross-sectional area of a rectangular sealing ring that is fitted in a sealing groove to a cross-sectional area of this sealing groove.

[0007] Regarding this, the inventor has carried out testing to investigate an operating state of a rectangular sealing ring in which leakage occurs, and has discovered the root cause of the problem: during operation of the electric motor, a partial region of the rectangular sealing ring that is squeezed between two opposite component portions of the electric motor housing overturns in the corresponding sealing groove (that is, a bottom face of the rectangular sealing ring turns up toward one side relative to a bottom wall of the sealing groove, and even completely overturns), and this type of overturning is such that the rectangular sealing ring is no longer able to tightly plug the gap between the two opposite component portions of the electric motor housing, thus causing leakage of cooling liquid. This discovery also does not conform to common understanding of good operating stability of arectangular sealing ring. Through further research, the inventor has recognized that the reason that the rectangular sealing ring overturns lies in that, in order to facilitate fitting the rectangular sealing ring in the sealing groove, assembly of the rectangular sealing ring in the sealing groove achieves insufficient sealing in a width direction, and a relatively large gap even appears between the sealing ring and a side wall of the groove; during operation of the electric motor, as the load changes, a highly fluctuating pressure is usually present in the cooling liquid passage, and such a pressure acts on the rectangular sealing ring, greatly increasing the probability that a region of the sealing ring in the sealing groove that achieves insufficient sealing in the width direction overturns. Therefore, to prevent overturning, when designing and assembling the rectangular sealing ring, a degree of cooperative sealing should be increased between the sealing ring and the sealing groove in the width direction.

[0008] Thus, the present invention proposes “widthwise compression rate” to act as another standard to consider when designing and assembling a rectangular sealing ring, in addition to “heightwise compression rate” and “cross-sectional fill rate”, and designs a corresponding axial sealing structure with a rectangular sealing ring to achieve the above object of the present invention. In the present application, “widthwise compression rate” refers to a ratio of a difference between an original width of a rectangular sealing ring and a width thereof after being fitted in a corresponding sealing groove to the original width thereof.

[0009] On the basis of the above research, one aspect of the present invention provides an axial sealing structure, comprising a sealing groove that is formed on a surface of a first component and a rectangular sealing ring that is fitted in the sealing groove, the rectangular sealing ring being squeezed between a second component that is arranged opposite the first component and a bottom wall of the sealing groove, to seal a gap between the first component and the second component. The rectangular sealing ring that has been fitted is provided with multiple support part sections that are spaced apart from each other on a circumference of the rectangular sealing ring, each support part section abutting two sidewalls of the sealing groove, a widthwise compression rate of the rectangular sealing ring at each support part section being set to be above a preset lower limit value, so that the rectangular sealing ring, at an operating pressure thereof, does not overturn in the sealing groove.

[0010] According to an embodiment of the present invention, when an operating pressure of the rectangular sealing ring is in a range of -1 bar to 2.5 bar (i.e. -100 kPa to 250 kPa), the preset lower limit value is 1.6%.

[0011] According to an embodiment of the present invention, the widthwise compression rate of the rectangular sealing ring at each support part section is further set to be below a preset upper limit value, such as 10.6%, to facilitate fitting the rectangular sealing ring in the sealing groove.

[0012] According to an embodiment of the present invention, the widthwise compression rate of the rectangular sealing ring at each support part section is set to be about 6.3%.

[0013] According to an embodiment of the present invention, a width of the rectangular sealing ring at each support part section is 3.2±0.1 millimeters, and a width of the sealing groove is 3.0±0.05 millimeters.

[0014] According to an embodiment of the present invention, a heightwise compression rate of the rectangular sealing ring in the sealing groove is set to be in a range of 15% to 35%, and a cross-sectional fill rate is set to be in a range of 63.4% to 89.6%.

[0015] According to an embodiment of the present invention, the rectangular sealing ring comprises a main body that has a rectangular cross section and overall extends in a ring shape, and each support part section comprises at least one respective protruding part that respectively extends from two side faces of the main body toward a corresponding side wall of the sealing groove.

[0016] Another aspect of the present invention relates to an electric motor housing, comprising a cylindrical main housing that is used for accommodating a rotor and a stator, and two end housings that are respectively connected at two axial ends of the main housing, a wall of the electric motor housing being internally provided with a cooling liquid passage that at least partially extends from one of the end housings, through the main housing, to the other of the end housings, the electric motor housing further comprising the axial sealing structure according to any of the aboveembodiments arranged between an end face of at least one of the end housings and a corresponding end face of the main housing, to surround the cooling liquid passage that extends across a gap between this two end faces for sealing, wherein one of the at least one of the end housings and the main housing acts as the first component, and the other acts as the second component.

[0017] According to an embodiment of the present invention, one of the two end housings is a front housing for accommodating an end bearing of a rotor shaft or is an electric motor speed reducer housing, and the other of the two end housings is a rear housing for accommodating another end bearing of a rotor shaft.

[0018] According to an embodiment of the present invention, multiple positions on a circumference of the electric motor housing are provided with the cooling liquid passages, the electric motor housing comprising corresponding multiple axial sealing structures that are arranged on the circumference, rectangular sealing rings in the respective axial sealing structures being connected to each other to form an integrated rectangular sealing ring assembly that is circumferentially sealing, and sealing grooves in the respective axial sealing structures being connected to each other to form an integrated groove that matches a shape of the integrated rectangular sealing ring assembly.

[0019] The present invention at least has one or more of the following beneficial effects: the present invention has identified through research and proposes a new parameter of “widthwise compression rate” that needs to be taken into consideration in the design and assembly of a rectangular sealing ring, and further provides an advantageous range for this parameter, not only able to increase the stability of fit of the rectangular sealing ring in a sealing groove at an operating pressure thereof, reducing a risk of leakage, but also able to ensure assembly convenience of the rectangular sealing ring when a large batch is used, thereby greatly increasing a yield rate and a production rate of device products having the axial sealing structure with the rectangular sealing ring.Brief Description of the Drawings

[0020] The features and advantages of the present invention will be clearlyunderstood by means of the following detailed description provided with reference to the drawings. It should be understood that the drawings listed below are merely schematic and not drawn to scale, so should not be regarded as limiting the present application, wherein:Fig. 1 is a three-dimensional drawing of an electric motor housing according to an embodiment of the present invention.Fig. 2 is a sectional view of the electric motor housing shown in Fig. 1 and the interior thereof.Fig. 3 is a three-dimensional drawing of a main housing in the electric motor housing shown in Fig. 1.Fig. 4 is a front view of an inner side of one end housing (a rear housing) in the electric motor housing shown in Fig. 1.Fig. 5 is a front view of an integrated rectangular sealing ring assembly in an axial sealing structure used in the electric motor housing shown in Fig. 1.Fig. 6 is a schematic drawing of the integrated rectangular sealing ring assembly shown in Fig. 5 assembled on the rear housing shown in Fig. 4.Fig. 7 is a schematic top view showing a state of a section of a rectangular sealing ring fitted in a sealing groove according to an embodiment of the present invention.Fig. 8 shows sectional views taken along lines A-A and B-B in Fig. 7.Particular Embodiments

[0021] Embodiments of the present invention are described below with reference to the drawings. Many specific details are expounded in the following description so that those skilled in the art can understand and realize the present invention more comprehensively. However, it is obvious to those skilled in the art that the invention can be realized without some of these specific details. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, consideration may be given to the use of any combination of the following various features and key elements to implement the present invention, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages merely serve an explanatory purpose, and should not be regarded as key elements or definitions of the claims, unless explicitly stated in the claims.

[0022] Figs. 1 and 2 show an overall view of an electric motor housing 100 according to an embodiment of the present invention, which comprises an axial sealing structure with a rectangular sealing ring that is recounted below. The electric motor housing 100 may comprise a main housing 10 and two end housings 20, 30. The main housing 10 is cylindrical, and is mainly used for accommodating a stator 11 and a rotor 12 of an electric motor. The rotor 12 is mounted on a rotor shaft 13, and the rotor shaft 13 is supported, respectively by an end bearing 21 thereof and another end bearing 31 thereof, on the two end housings 20, 30. The two end housings 20, 30 are respectively connected at two axial ends of the main housing 10, and these housing component portions, for example, are fastened together by means of multiple fasteners 14 (Fig. 2 only showing one of them) that are arranged in a circumferential direction. In one embodiment, according to a configuration and a mounting state of the electric motor, the end housing 30 may be a front housing of the electric motor, and the end housing 20 may be a rear housing of the electric motor, and a rear cover 40 of the electric motor may further be connected on this rear housing. In another embodiment, the end housing 30 may also be an electric motor speed reducer housing.

[0023] To perform heat dissipation and cooling on the electric motor during operation, a cooling liquid passage may be provided in a wall of the electric motor housing, and at least a portion thereof may extend from one of the end housings, through the main housing, to the other of the end housings, and therefore spans a gap between the end housing and the main housing, thereby allowing the possibility for cooling liquid to flow out from this gap. For this reason, an axial sealing structure may be arranged around the cooling liquid passage between the end housing and the main housing, wherein a rectangular sealing ring that is fitted in a sealing groove is used to seal the gap. As shown in the enlarged views in the two boxes on the right side in Fig. 2, an axial sealing structure with a rectangular sealing ring 50 may be provided between the main housing 10 and either or both of the end housings 20, 30.

[0024] Fig. 3 is a three-dimensional drawing of the main housing 10, showing an end face 15 thereof to be fitted together with the end housing 20 or 30 such that the end face and end housing face each other. It can be seen that this end face 15 is annular, and is also an end face of a wall of the main housing 10; moreover, on the mainhousing, an opening 16 of the cooling liquid passage extending in an axial direction of the main housing can be seen, for example, on this end face. To improve an effect and uniformity of cooling, multiple positions on a circumference of the electric motor housing may all be provided with such a cooling liquid passage; in the embodiment shown, six cooling liquid passages arranged uniformly along the circumference are shown. Correspondingly, Fig. 4 shows an inner side (that is, a side facing the interior of the electric motor) of the end housing 20, for example, as the rear housing, which comprises an end face 25 to be fitted together with the end face 15 of the main housing 10 such that the two end faces face each other. On the end housing 20, corresponding openings 26 of the cooling liquid passages are provided on the end face 25. When the main housing 10 and the end housing 20 are assembled in place, the respective openings 16 on the main housing 10 are in one-to-one alignment with the corresponding openings 26 on the end housing 20, so as to form cooling liquid passages that extend across the gap between the main housing 10 and the end housing 20.

[0025] An axial sealing structure is arranged between the main housing 10 and the end housing 20 that are arranged to face each other, and comprises a sealing groove 60 that is formed on the end face 25 of the end housing 20, and a rectangular sealing ring 50 that is fitted in this sealing groove. As an alternative embodiment, the sealing groove 60 may also be formed on the end face 15 of the main housing 10. In a box on the right side in Fig. 4, an enlarged view of a sealing groove 60 is shown (see the portion shaded with oblique lines), the sealing groove being in a shape similar to a trapezoid, for example, and surrounding a corresponding cooling liquid passage. In a box on the right side in Fig. 5, an enlarged view of a corresponding rectangular sealing ring 50 fitted in the sealing groove 60 is shown, the rectangular sealing ring matching the sealing groove 60 in shape, and also correspondingly surrounding the same cooling liquid passage once fitted in the sealing groove 60. When the main housing 10 and the end housing 20 are assembled together, the rectangular sealing ring 50 fitted in the sealing groove 60 is squeezed between the end face 15 of the main housing 10 and a bottom wall of the sealing groove 60, thereby sealing the corresponding cooling liquid passage, to prevent cooling liquid from leaking out from the gap between the end face 15 of the main housing 10 and the end face 25 of the end housing 20.

[0026] Corresponding to multiple liquid cooling passages that are arranged on the circumference of the electric motor housing, multiple sealing grooves 60 are also formed along the circumference of the end face 25 of the end housing 20, respectively for receiving multiple corresponding rectangular sealing rings 50. In the embodiment shown, corresponding to the six cooling liquid passages arranged equidistant from each other on the circumference, six pairs of sealing grooves 60 / rectangular sealing rings 50 are provided, likewise arranged equidistant from each other on the circumference. To improve the ease of installing the multiple rectangular sealing rings, as shown in Fig. 5, multiple rectangular sealing rings 50 arranged along the circumference, for example, may be connected to each other by a connecting portion 55 shown in the dotted box to form an integrated rectangular sealing ring assembly 500. It can be seen that this integrated rectangular sealing ring assembly 500 is also circumferentially sealing, and therefore may be seen as a large rectangular sealing ring. Correspondingly, as shown in Fig. 4, multiple sealing grooves 60 arranged along the circumference of the end face 25 of the end housing 20 may also be connected to each other to form an integrated groove 600, which has a shape that matches the shape of the integrated rectangular sealing ring assembly 500. In this way, as shown in Fig. 6, the integrated rectangular sealing ring assembly 500 comprising the multiple rectangular sealing rings 50 may be conveniently fitted in the integrated sealing groove 600 in one step.

[0027] An explanation is given below of specific details of the rectangular sealing ring 50 and the sealing groove 60 in the axial sealing structure according to the present invention. As shown in Figs. 5, 7 and 8 which show the rectangular sealing ring in detail, the rectangular sealing ring 50 comprises a main body 501 that has a rectangular cross section and overall extends in a ring shape (a ring similar to a trapezoid in Fig. 5), and a bottom face of the main body 501, once assembled in place, abuts a bottom wall 601 of the sealing groove 60 that likewise has a rectangular cross section. However, for the convenience of manufacture and assembly, the rectangular sealing ring 50, in the width direction (the left-right direction in Figs. 7 and 8), is not and does not need to be a completely perfect fit when fitted in the sealing groove 60. Rather, the rectangular sealing ring 50 is provided with multiple support part sections 502 (circles are only used to indicate three thereof in Fig. 5) that are spaced apart from each other on the circumference of the rectangular sealing ring 50, whichhas a greater width at these support part sections than at the remaining part sections. Therefore, when the rectangular sealing ring 50 is fitted in the sealing groove 60, these support part sections 502 may be supported on a side wall 603 of the sealing groove 60 in a circumferentially distributed manner depending on the situation, to increase the installation stability of the rectangular sealing ring 50. According to the overall size of the rectangular sealing ring, a distance D between two support part sections that are adjacent on the circumference may be appropriately set; this distance in an existing rectangular sealing ring is 14 millimeters for example. In an embodiment, as shown in Figs. 7 and 8, the support part section 502 may comprise respective at least one protruding part 503 (also called a “stabilizer”) that respectively extends out from either side face of the main body 501 of the rectangular sealing ring 50 toward the corresponding side wall 603 of the sealing groove 60. In the shown embodiment, in the same support part section 502, the number of protruding parts 503 that extend out from one side face of the main body 501 is one or two, and all three protruding parts 503 in this support part section 502 are arranged in a triangle. However, the number and arrangement of protruding parts 503 are not limited to this, as long as the rectangular sealing ring 50 can be supported. Furthermore, the support part section 502 is also not limited to a configuration of the protruding part extending out from the side face of the sealing ring main body, rather also may be, for example, a part section with a gradually increasing width of a sealing ring main body with a cross section that is not constant in width.

[0028] As described above, in the prior art, there is no specified standard for the design of a rectangular sealing ring; it normally suffices to consult a design standard for an O-shaped sealing ring to investigate a heightwise compression rate and a cross-sectional fill rate, and as long as a rectangular sealing ring product satisfies the specified standards of these two parameters, it is generally able to meet performance requirements. However, it has been discovered that although a rectangular sealing ring with the above configuration satisfies design requirements for heightwise compression rate and cross-sectional fill rate, leakage still occurs after the rectangular sealing ring is fitted in place in an electric motor housing. Through investigative research into the operating state of a rectangular sealing ring after leakage has occurred, the inventor has unexpectedly realized that the leakage is caused by a partial region of the rectangular sealing ring overturning in the sealinggroove during operation of the electric motor. It is generally considered that the rectangular sealing ring has a better operating stability due to the shape of the cross section thereof, and, if further combined with the multiple support part sections arranged thereon, then it is difficult for the sealing ring to overturn in the sealing groove. However, it has been discovered through further research that despite having relatively wide support part sections, existing rectangular sealing rings still do not fit with sufficient tightness in the width direction in sealing grooves, and an obvious gap can even be observed between the support part section and the groove side wall; although advantageous for conveniently fitting the rectangular sealing ring in the sealing groove, this type of assembly gap causes the rectangular sealing ring to overturn at an operating pressure thereof, thereby being a key reason for leakage.

[0029] Regarding this, the present invention considers that when designing and assembling the rectangular sealing ring, a degree of cooperative sealing should be increased between the rectangular sealing ring and the sealing groove in the width direction, to increase the fit stability of the rectangular sealing ring in the sealing groove, to prevent the sealing ring from overturning. On the basis of this consideration, the present invention proposes “widthwise compression rate” to act as another standard to consider when designing and assembling a rectangular sealing ring, in addition to “heightwise compression rate” and “cross-sectional fill rate”. More specifically, as shown in Figs. 7 and 8, at each support part section 502 thereof, the rectangular sealing ring 50 fitted in the sealing groove 60 should abut the two side walls 603 of the sealing groove, to at least eliminate the assembly gap; furthermore, the widthwise compression rate of the rectangular sealing ring 50 at each support part section 502 should be above a preset lower limit value, and this preset lower limit value is set such that the rectangular sealing ring 50 does not overturn in the sealing groove 60 at an operating pressure thereof.

[0030] In the present invention, “widthwise compression rate” is defined as a ratio of a difference between an original width of a rectangular sealing ring and a width thereof after being fitted in a corresponding sealing groove to the original width thereof. According to the present invention, since at each support part section 502 thereof, the fitted rectangular sealing ring 50 must abut the two side walls 603 of the sealing groove, the widthwise compression rate of the rectangular sealing ring 50 ateach support part section 502 is equal to a ratio of a difference between an original width of the rectangular sealing ring at each support part section 502 and a width W of the sealing groove 60 to said original width, and is a value above 0; whereas in the prior art, since gaps are present between the rectangular sealing ring at the support part sections where the width is greatest and the groove side walls, the widthwise compression rate calculated according to this method may even be a negative value.

[0031] On this basis, in the present invention, different rectangular sealing ring original width dimensions (at each support part section) and different sealing groove widths are designed, and the widthwise compression rate is set in view of results of actual leak tests and computer simulations. By combining various simulations and test data, it can be seen that, when the preset lower limit value is 1.6%, the rectangular sealing ring does not overturn and leak in the sealing groove at an operating pressure of -1 bar to 2.5 bar. The operating pressure range may cover most application scenarios of the rectangular sealing ring, and in particular is suitable for the case of sealing cooling liquid in an electric motor, wherein a negative pressure corresponds to a vacuum negative pressure state when the cooling liquid passage is first filled with cooling liquid, and an increased pressure corresponds to an increased electric motor load.

[0032] In terms of preventing the rectangular sealing ring from overturning, it is better if the widthwise compression rate thereof is a bit higher. However, an excessively high widthwise compression rate means the difference between the original width of the rectangular sealing ring and the width of the sealing groove will be large, making it difficult to fit the rectangular sealing ring into the sealing groove, increasing the manufacturing difficulty and cost of the product. For this reason, the present invention further proposes setting the widthwise compression rate of the rectangular sealing ring at each support part section to be below a preset upper limit value, to facilitate fitting the rectangular sealing ring into the sealing groove. Through actual assembly tests, this preset upper limit value may be set to be 10.6% for example.

[0033] Therefore, for an operating pressure range of -1 bar to 2.5 bar, the widthwise compression rate of the rectangular sealing ring according to an embodiment may advantageously be set in a range of 1.6% to 10.6%, and more preferably a widthwisecompression rate of about 6.3% may be selected as a nominal value thereof.

[0034] Matching the widthwise compression rate, according to test data, a rectangular sealing ring of existing dimensions may have a width at each support part section of 3.2 ±0.1 millimeters (as a non-limiting example, the width of the main body 501 of the rectangular sealing ring is 1.85±0.1 millimeters, and the total width of the main body 501 and a protruding part 503 on one side is 2.525±0.1 millimeters); by performing simulations and tests on sealing grooves with different widths, it has been ascertained that when this rectangular sealing ring is fitted in a sealing groove with a width of 3.0±0.05 millimeters, the rectangular sealing ring does not overturn and leak during operation at an operating pressure of -1 bar to 2.5 bar. Compared with a groove width in an existing axial sealing structure that leaks, the width of this sealing groove is smaller.

[0035] A person skilled in the art will understand that, as well as reducing the width of the sealing groove compared to the prior art, the width of the rectangular sealing ring at each support part section may also be increased compared to the prior art, or the width of the sealing groove may be reduced while also increasing the width of the rectangular sealing ring, which, compared to the prior art, can both increase the widthwise compression rate to be in the range determined to be advantageous as described above, thereby preventing the rectangular sealing ring from overturning and leaking at operating pressure.

[0036] In addition to the widthwise compression rate, the heightwise compression rate and the cross-sectional fill rate of the rectangular sealing ring 50 may be set by consulting a specified standard for an O-shaped sealing ring such as that in the prior art. For example, the heightwise compression rate may be set to be in a range of 15% to 35%, for example 15.5% to 35%, and preferably is a nominal value of 23.1%, wherein an original height of the rectangular sealing ring 50 may be 2.6±0.1 millimeters, and a height thereof once fitted in place in the sealing groove or a depth H of the sealing groove may be 2.0±0.05 millimeters. The cross-sectional fill rate may be set to be in a range of 63.4% to 89.6%, for example 68.8% to 88.6%, and preferably is a nominal value of 80.5%. The rectangular sealing ring 50 may be made from any appropriate sealing material, typically rubber, such as EPDM (ethylene propylene diene monomer) rubber with a hardness of HS 70±5.

[0037] As described above, the present invention proposes a new parameter of “widthwise compression rate” that needs to be taken into consideration in the design and assembly of a rectangular sealing ring, and further provides an advantageous range for this parameter, not only able to increase the stability of fit of the rectangular sealing ring in a sealing groove at an operating pressure thereof, reducing a risk of leakage, but also able to ensure assembly convenience of the rectangular sealing ring when a large batch is used, thereby greatly increasing a yield rate and a production rate of device products having the axial sealing structure with the rectangular sealing ring.

[0038] Above, an electric motor housing is taken as an example to explain an application of the axial sealing structure and a rectangular sealing ring thereof according to the present invention, but the present invention is not limited to this. A person skilled in the art will easily understand that the basic concept of the present invention is suitable for application scenarios of various axial sealing structures with rectangular sealing members.

[0039] For a person skilled in the art, various amendments and changes may be made to the embodiments disclosed above without departing from the scope or spirit of the present invention. According to the implementation of the present invention as disclosed in the present Description, other embodiments of the present invention would be obvious to a person skilled in the art. The present Description and examples disclosed thereby should be considered only as exemplary; the true scope of the present invention is designated by the appended claims and equivalents thereof.

Claims

Claims1. An axial sealing structure, comprising a sealing groove that is formed on a surface of a first component and a rectangular sealing ring that is fitted in the sealing groove, the rectangular sealing ring being squeezed between a second component that is arranged opposite the first component and a bottom wall of the sealing groove, to seal a gap between the first component and the second component, wherein the rectangular sealing ring that has been fitted is provided with multiple support part sections that are spaced apart from each other on a circumference of the rectangular sealing ring, each support part section abutting two sidewalls of the sealing groove, a widthwise compression rate of the rectangular sealing ring at each support part section being set to be above a preset lower limit value, so that the rectangular sealing ring, at an operating pressure thereof, does not overturn in the sealing groove.

2. The axial sealing structure as claimed in claim 1, wherein when the operating pressure of the rectangular sealing ring is in a range of -1 bar to 2.5 bar, the preset lower limit value is 1.6%.

3. The axial sealing structure as claimed in claim 1 or 2, wherein the widthwise compression rate of the rectangular sealing ring at each support part section is further set to be below a preset upper limit value, such as 10.6%, to facilitate fitting the rectangular sealing ring in the sealing groove.

4. The axial sealing structure as claimed in any one of claims 1 to 3, wherein the widthwise compression rate of the rectangular sealing ring at each support part section is set to be about 6.3%.

5. The axial sealing structure as claimed in any one of claims 1 to 4, wherein a width of the rectangular sealing ring at each support part section is 3.2±0.1 millimeters, and a width of the sealing groove is 3.0±0.05 millimeters.

6. The axial sealing structure as claimed in any one of claims 1 to 5, wherein a heightwise compression rate of the rectangular sealing ring in the sealing groove is set to be in a range of 15% to 35%, and a cross-sectional fill rate is set to be in a rangeof 63.4% to 89.6%.

7. The axial sealing structure as claimed in any one of claims 1 to 6, wherein the rectangular sealing ring comprises a main body that has a rectangular cross section and overall extends in a ring shape, and each support part section comprises respective at least one protruding part that respectively extends from either side face of the main body toward a corresponding side wall of the sealing groove.

8. An electric motor housing, comprising a cylindrical main housing that is used for accommodating a rotor and a stator, and two end housings that are respectively connected at two axial ends of the main housing, a wall of the electric motor housing being internally provided with a cooling liquid passage that at least partially extends from one of the end housings, through the main housing, to the other of the end housings, the electric motor housing further comprising the axial sealing structure as claimed in any one of claims 1 to 7 arranged between an end face of at least one of the end housings and a corresponding end face of the main housing, to surround the cooling liquid passage that extends across a gap between this two end faces for sealing, wherein one of the at least one of the end housings and the main housing acts as the first component, and the other acts as the second component.

9. The electric motor housing as claimed in claim 8, wherein one of the two end housings is a front housing for accommodating an end bearing of a rotor shaft or is an electric motor speed reducer housing, and the other of the two end housings is a rear housing for accommodating another end bearing of a rotor shaft.

10. The electric motor housing as claimed in claim 8 or 9, wherein multiple positions on a circumference of the electric motor housing are provided with the cooling liquid passages, the electric motor housing comprising corresponding multiple axial sealing structures that are arranged on the circumference, rectangular sealing rings in the respective axial sealing structures being connected to each other to form an integrated rectangular sealing ring assembly that is circumferentially sealing, and sealing grooves in the respective axial sealing structures being connected to each other to form an integrated groove that matches a shape of the integrated rectangular sealing ring assembly.

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