cap retention

Abstract

A low profile electric pump assembly has a motor housing connected to a pump element for a transmission of a vehicle. An inverter housing is connected to the motor housing and has an electronic control unit (ECU) connected through the inverter housing to selectively supply power to the motor. The recess and the ECU are covered by and sealed from the elements by a plastic cover. To achieve a low profile of the electric pump assembly so that it can fit within a desired packaging line on a transmission housing, a metal bracket is overmolded into the plastic cover. The metal bracket has at least one exposed surface that engages the inverter housing to hold the plastic cover in place on the inverter housing so that the plastic cover covers and seals the recess at a second side of the inverter housing and the ECU.

Description

[0001] Cross-references to related applications

[0002] This application is a PCT international application and claims the benefit of U.S. Patent Application No. 17 / 135,583, filed December 28, 2020. The disclosure of the above application is incorporated herein by reference. Technical Field

[0003] This invention relates to a molded plastic cover for providing a low-profile electric pump unit for a transmission with limited profile space. Background Technology

[0004] Several current transmission designs utilize electric oil pumps that provide fluid pressure to the vehicle's transmission. These electric oil pumps have a pump element connected to an electric motor. Typically, an electronic control unit (ECU) is connected to the motor to control the power supplied to it, which in turn controls the pump's output. An ECU cover is placed at the location of the ECU to protect it from external environmental influences. Making the ECU cover from plastic has several advantages. The plastic cover allows connectors to be molded into it, ensuring a seal and preventing fluid migration through the cover. Making ECU covers from other materials, such as metals, presents challenges in providing sealed connectors and does not offer the same level of corrosion resistance. However, the electric oil pump is connected to the transmission and must be placed in locations where space may be limited. Therefore, when using a plastic cover, it is not always possible to use conventional retention methods (i.e., using screws and bolts as limiters) to package the ECU cover due to extremely stringent packaging requirements.

[0005] Figure 1 depicts a cross-sectional side view of an electric pump assembly 10, which is part of the vehicle's transmission and connected to the transmission housing 38. The electric pump assembly 10 has an electronic control unit 12 covered by a one-piece plastic cover 14. This one-piece plastic cover 14 is connected to the motor housing 16 using two fasteners 18A and 18B, which extend through corresponding openings 20A and 20B formed by extensions 22A and 22B through the one-piece plastic cover 14. Extensions 22A and 22B are formed of the same plastic as the remainder of the one-piece plastic cover 14. Each extension 22A and 22B has a shoulder 24A and 24B with a thickness 26. The shoulders 24A and 24B extend downwards to one of the openings 20A and 20B with a thickness 30. Since each extension 22A, 22B is made of plastic, thicknesses 26 and 30 must be sized to accommodate compression limiters 32A, 32B in each orifice 20A, 20B. These compression limiters 32A, 32B will prevent excessive twisting of the corresponding fasteners 18A, 18B, which could cause the extensions 22A, 22B to break or damage other parts of the electric pump unit 10.

[0006] The transmission to which the electric pump unit 10 is connected has a packaging outline 34. As used herein, the packaging outline 34 is defined as a line drawn between gap points on the transmission housing 38. The electric pump unit 10, including the one-piece plastic cover 24 and each fastener 18A, 18B, must be located at a specific distance below the packaging outline 34. The “specific distance” may vary depending on the transmission design, but for example, the “specific distance” is typically at least 3 mm, meaning that the electric pump unit 10 must be at least 3 mm away from the packaging outline 34. For example, if, as shown in FIG. 1, the electric pump unit 10 extends into or beyond the packaging outline 34, this location is marked as packaging violation arrows 36A, 36B, 36C. Thicknesses 26 and 30 are problematic because the shoulder 24B and a portion of the fastener 18B are not fitted within the packaging outline 34 and, as shown in FIG. 1, are indicated by at least three packaging violation arrows 36A, 36B, 36C. Although the packaging violation arrows 36A, 36B, and 36C are shown in three different locations, it is also within the scope of this invention for packaging violations to occur in another location.

[0007] There is a need for an electric pump device that addresses all packaging violations and is fitted within a specified distance of the packaging outline. The prior art also requires an ECU cover made of plastic, rather than entirely of metal or some other material, because plastic is corrosion-resistant and non-conductive. Summary of the Invention

[0008] This invention provides a solution to problems encountered in the prior art by offering a low-profile electric pump device. The low-profile pump device includes a motor housing connected to a pump element for a vehicle's transmission. An inverter housing has a first side connected to the motor housing and a second side having a recess defined by an edge wall. Within the recess is an electronic control unit (ECU), connected via the inverter housing to selectively supply power to the motor within the motor housing.

[0009] The recesses of the inverter housing and the ECU are covered by a plastic cover and sealed to the components via the plastic cover. The plastic cover has a periphery sized to cover the recess and seal against an edge wall. To achieve a low profile for the electric pump unit, allowing it to fit within a desired packaging line on the transmission housing, a metal bracket is overmolded into the plastic cover. The metal bracket has at least one exposed surface that engages the inverter housing to hold the plastic cover in place on the inverter housing, such that the plastic cover covers and seals the recesses at the second side of the ECU and inverter housing.

[0010] Other applicable areas of the invention will become apparent from the detailed description provided below. It should be understood that while the detailed description and specific examples illustrate preferred embodiments of the invention, they are intended for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0011] The invention will be more fully understood from the detailed description and accompanying drawings.

[0012] Figure 1 is a cross-sectional side view of an electric pump device according to the prior art.

[0013] Figure 2 This is a cross-sectional side view of a low-profile electric pump device according to a first embodiment of the present invention.

[0014] Figure 3 This is a cross-sectional side view of a low-profile electric pump device according to a second embodiment of the present invention.

[0015] Figure 4 This is a cross-sectional side view of a low-profile electric pump device according to a third embodiment of the present invention.

[0016] Figure 5 This is a perspective view of the bottom side of a plastic cap according to another embodiment of the present invention. Detailed Implementation

[0017] The following description of preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or its use.

[0018] Throughout the following description, the same reference numerals indicate the same or corresponding parts in different embodiments. Furthermore, the same reference numerals shown in FIG1 are used to indicate... Figures 2 to 4 The same structure as in [the text]. Figures 2 to 4 Low-profile electric pumps 100, 200, and 300 according to three different embodiments are depicted, which are used to replace the electric pump device 10 shown in FIG1. Figures 2 to 4 As shown, the packaging outline 34 and the transmission housing 38 are generally the same structure as shown in Figure 1. The packaging outline 34 is defined by gaps located on the transmission housing 38. Figures 2 to 4 In the embodiment shown, the motor housing, inverter housing, and plastic cover are all located at a certain distance within the packaging outline, without any packaging violations.

[0019] Now refer to Figures 2 to 3 and Figure 5 This invention includes two different embodiments relating to low-profile electric pump units 100 and 200 for use in locations where space is limited for connecting the electric pump (i.e., compact packaging requirements). There are some common elements between the two embodiments, which will now be discussed together. The low-profile electric pump units 100 and 200 can be used in any type of application, and the illustrated embodiments depict low-profile electric pump units 100 and 200 connected to the vehicle's transmission housing 38 instead of the electric pump unit 10 shown in FIG. 1. Figures 2 to 3 and Figure 5 In this context, the same reference numerals from Figure 1 will also be used to denote the same structures. The transmission housing 38 has a pump section 104 that houses a suitable pumping element, such as a cycloidal pump, a vane pump, or any other suitable type of pump for pumping fluid within the transmission housing 38.

[0020] The pump element within pump section 104 is driven by a motor housed within motor housings 106 and 206 connected to pump section 104. Motor housings 106 and 206 house a stator and rotor 105, which, when energized, rotate the pump element. The power supplied to the rotor and stator 105 is controlled by an electronic control unit 108 mounted to inverter housings 112 and 212, which are connected to motor housings 106 and 206 and serve as heat sinks. Inverter housings 112 and 212 have first sides 114 and 214 connected to motor housings 106 and 206 and second sides 116 and 216 connected to inverter housings 112 and 212, respectively. The second sides 116 and 216 have recesses 118 and 218 defined by edge walls 122 and 222, and openings. ECU 108 is connected to inverter housings 112, 212 within recesses 118, 218. All embodiments also include plastic covers 124, 224, having connectors 123, 223 formed through the plastic covers 124, 224, which are sealed connections for supplying power to ECU 108.

[0021] Reference Figure 2 The low-profile electric pump device 100 shown has a plastic cover 124 with a periphery 126 sized to cover a recess 118 and seal against the edge wall 122 of the recess 118. The plastic cover 124 also includes a metal support 130 made of low-carbon steel, having an overmolded portion 133 molded into the plastic cover 124. The metal support 130 has at least one exposed surface, which in this embodiment of the invention is a pair of arms 132A, 132B extending away from the plastic cover 124 and the overmolded portion 133 of the metal support 130, beyond the periphery 126 of the plastic cover 124. The plastic cover 124 has an inner surface 140 and an outer surface 142 having a first plane 144. Each arm 132A, 132B has a shoulder 134A, 134B extending away from the plastic cover 124 beyond the inner surface 140, and then each arm 132A, 132B bends away from the plastic cover 124 to form fastener protrusions 136A, 136B, which have a second plane 146 parallel to the first plane 144. The entire metal bracket 130, including the shoulders 134A, 134B and the fastener protrusions 136A, 136B, has a thickness of approximately 1.5 mm or less.

[0022] Each fastener protrusion 136A, 136B includes orifices 138A, 138B, sized to receive fasteners 148A, 148B. Each fastener 148A, 148B has a head 150A, 150B and a threaded shaft 152A, 152B with a diameter extending from the head 150A, 150B. Orifices 138A, 138B are clearance orifices, which are larger in diameter than the threaded shafts 152A, 152B of the fasteners 148A, 148B, such that the threaded shafts 152A, 152B pass through the orifices 138A, 138B of the fastener protrusions 136A, 136B. The inverter housing 112 has flanges 158A and 158B, which have clearance orifices 160A and 160B in the inverter housing 112. These clearance orifices are larger than the diameter of the threaded shafts 152 of the fasteners 148A and 148B, through which the threaded shafts 152A and 152B pass. The motor housing 106 has flanges 154A and 154B, which have threaded fastener orifices 156A and 156B formed therein. The threaded fastener orifices 156A and 156B are threaded and mate with the corresponding threaded shafts 152A and 152B of the fasteners 148A and 148B to form a threaded connection. When fasteners 148A and 148B are connected to threaded fastener holes 156A and 156B, the heads 150A and 150B of fasteners 148A and 148B contact a portion of the fastener protrusions 136A and 136B around the periphery of the holes 138A and 138B, such that the heads 150A and 150B press against the fastener protrusions 136A and 136B, thereby holding the plastic cover 124 and the inverter housing 112 against the motor housing 106 by means of a threaded connection. This connection holds the plastic cover 124 in place against the inverter housing 112, such that the plastic cover 124 covers and seals the recess 118 of the second side 116 of the ECU 108 and the inverter housing 112. Although two arms 132A and 132B and their corresponding connections have been described, the use of more or fewer arms on the metal bracket 130 is also within the scope of the invention, depending on the needs of a particular application.

[0023] In this embodiment of the invention, the use of the metal support 130 combined with its overlay molding onto the plastic cover 124 represents an improvement over the electric pump device 10 in FIG1, because the low profile electric pump 100 ensures that, when assembled, the motor housing 106, inverter housing 112, and plastic cover 124 are located at a certain distance within the packaging outline 34, thus eliminating the packaging irregularities shown in FIG1.

[0024] Figure 3A low-profile electric pump device 200 according to a second embodiment of the present invention is depicted. In this embodiment, the low-profile electric pump device 200 has a plastic cover 224 that is not connected to the motor housing 206 using any fasteners. This eliminates the need for... Figure 2 The inverter housing flanges 158A and 158B and the motor housing flanges 154A and 154B shown make the profile of the electric pump assembly 200 smaller than that of the electric pump assembly 100 and the electric pump assembly 10. Therefore, the low-profile electric pump 200 ensures that, during assembly, the motor housing 206, inverter housing 212, and plastic cover 224 are well positioned within a certain distance of the packaging outline 34, thus eliminating the packaging irregularities shown in FIG. 1.

[0025] The plastic cover 224 has a periphery 226, which is dimensioned to cover the recess 218 and seal against the edge wall 222 of the recess 218 of the inverter housing 216. The plastic cover 224 has a ring-shaped metal support 230 made of aluminum. The advantage of using aluminum is that the inverter housing is also made of aluminum, and both being made of aluminum means there is no relative thermal expansion under hot or cold operating conditions. However, the invention is not limited to the metal support 230 being ring-shaped or made of aluminum. The metal support 230 can actually have any type of shape conforming to the periphery 228 of the plastic cover 224 and can be made of any type of malleable material.

[0026] The metal bracket 230 is overmolded onto the plastic cover 224, resulting in an exposed surface 232 extending beyond the periphery 226 of the plastic cover 224. The metal bracket 230 is slightly larger than the inner diameter of the edge wall 222 of the recess 218. Because the metal bracket 230 is made of aluminum, it is malleable, such that when the plastic cover 224 is attached to the inverter housing 212, the exposed surface 232 is shaped between the plastic cover 224 and the edge wall 222 of the recess 218 of the inverter housing 212, forming a press-fit connection.

[0027] Figure 4 Another embodiment of the low-profile pump device 300 is depicted, wherein the plastic cover 324 has a metal support 330, the metal support 330 having one or more grooves 331 on the exposed surface 332 such that when the plastic cover 324 is attached to the inverter housing 212, one or more grooves 331 deform and provide a press-fit connection between the plastic cover 324 and the edge wall 222 of the recess 218 of the inverter housing 212.

[0028] Figure 5A plastic cap 424 with a metal support 430 is depicted as an alternative embodiment of the invention. In this embodiment, the metal support 430 includes a plurality of teeth 431 and a plurality of recesses 432 surrounding the outer diameter circumference of the metal support 430, the recesses 432 being spaced apart between each pair of teeth. When the metal support 430 is overmolded onto the plastic cap 424, plastic material is formed in the plurality of recesses 432 to secure the metal support 430 to the plastic cap 424. This also secures the metal support 430 to the plastic cap 424 in a manner that prevents the metal support 430 from rotating.

[0029] Reference Figures 2 to 4 Each embodiment of the plastic cover 124, 224, 334 has circumferential grooves 162, 162', 162" and corresponding sealing gaskets 164, 164', 164" located therein. The circumferential grooves 162, 162', 162" and the sealing gaskets 164, 164', 164" are located below the metal supports 130, 230, 330, respectively, and the rubber gaskets 164, 164', 164" deform and press against the edge walls 122, 222 of the recesses 118, 218 to provide a seal between the plastic cover 124, 224, 334 and the inverter housing 112, 212.

[0030] exist Figure 3 and Figure 4 In the embodiment of the invention shown, the use of metal supports 230, 330 combined with their overmolding onto plastic caps 224, 324 represents an improvement over the electric pump unit 10 in FIG. 1, because the low-profile electric pump units 200, 300 ensure that, when assembled, the motor housing 206, inverter housing 212, and plastic caps 224, 324 are located at a certain distance within the packaging outline 34, thus eliminating the packaging irregularities shown in FIG. 1.

[0031] The description of this invention is exemplary in nature only, and therefore, variations that do not depart from the spirit of the invention are also intended to be within the scope of the invention. These variations should not be considered as a departure from the spirit and scope of the invention.

Claims

1. A low-profile electric pump device, comprising: Motor housing; An inverter housing having a first side portion connected to the motor housing and a second side portion of the inverter housing having a recess defined by an edge wall; An electronic control unit, the electronic control unit being located within the recess on the second side of the inverter housing; A plastic cap having a periphery sized to cover the recess and seal against the edge wall of the recess, and A metal bracket, which is overmolded into the plastic cover, has at least one exposed surface that engages the inverter housing to hold the plastic cover in place on the inverter housing, such that the plastic cover covers and seals the recess at the second side of the electronic control unit and the inverter housing.

2. The low-profile electric pump device according to claim 1, further comprising: The metal support is encapsulated within the plastic cover in a molded, overlaid portion, and the at least one exposed surface of the metal support is an arm extending away from the plastic cover and the molded, overlaid portion of the metal support, beyond the periphery of the plastic cover. The arm has a fastener protrusion with a hole sized to receive a fastener. The fastener is used to connect the metal bracket and the plastic cover to the motor housing and to hold the plastic cover against the inverter housing in place, such that the plastic cover seals and covers the recess on the second side of the electronic control unit and the inverter housing.

3. The low-profile electric pump device according to claim 2, wherein, The metal support is made of steel.

4. The low-profile electric pump device according to claim 2, wherein, The plastic cap has an inner surface and an outer surface, the outer surface having a first plane, and the arm having a shoulder extending beyond the inner surface, bending away from the plastic cap and forming a fastener protrusion, wherein the orifice of the arm is located at the fastener protrusion, and the fastener protrusion has a second plane parallel to the first plane of the outer surface of the plastic cap.

5. The low-profile electric pump device according to claim 2, wherein, The arm has a shoulder that extends away from the plastic cover and terminates at a fastener protrusion, wherein the orifice of the arm is positioned to penetrate the fastener protrusion.

6. The low-profile electric pump device according to claim 5, wherein, The shoulder and the fastener protrusion have a thickness of 1.5 mm or less.

7. The low-profile electric pump device according to claim 2, wherein, The arm has a thickness of 1.5 mm or less.

8. The low-profile electric pump device according to claim 2, further comprising: in, The fastener has a head and a threaded shaft extending from the head, wherein the threaded shaft has a diameter; A threaded fastener hole is formed in the motor housing, wherein the threaded fastener hole is threaded and mates with the threaded shaft of the fastener to form a threaded connection. The gap orifice in the inverter housing is larger than the diameter of the threaded shaft of the fastener, wherein the threaded shaft passes through the gap orifice of the inverter housing. Wherein, the orifice of the fastener protrusion of the arm is a clearance orifice with a diameter larger than that of the threaded shaft of the fastener, such that the threaded shaft passes through the orifice of the fastener protrusion, and the head of the fastener contacts a portion of the periphery of the orifice of the fastener protrusion such that the head presses against the fastener protrusion, thereby using the threaded connection to hold the plastic cover and the inverter housing against the motor housing.

9. The low-profile electric pump device according to claim 1, wherein, The metal bracket has a shape that conforms to the periphery of the plastic cover and has an exposed surface that extends beyond the periphery of the plastic cover, and the metal bracket is larger than the edge wall of the recess, wherein the metal bracket is extendable such that when the plastic cover is connected to the inverter housing, the exposed surface is shaped between the plastic cover and the edge wall of the recess of the inverter housing to form a press-fit connection.

10. The low-profile electric pump device according to claim 9, wherein, The metal support is made of aluminum.

11. The low-profile electric pump device according to claim 9, wherein, The exposed surface has one or more grooves such that when the plastic cover is attached to the inverter housing, the one or more grooves deform and provide a press-fit connection between the plastic cover and the edge wall of the recess in the inverter housing.

12. The low-profile electric pump device according to claim 9, wherein, The metal bracket has a plurality of teeth and a plurality of recesses surrounding the outer periphery of the metal bracket, the plurality of recesses being spaced apart from each of the plurality of teeth, wherein plastic material for forming the plastic cover is formed in the plurality of recesses to secure the metal bracket to the plastic cover.

13. The low-profile electric pump device according to claim 9, further comprising: A circumferential groove, the groove being located below the metal bracket, and A rubber gasket is located within the groove, wherein the rubber gasket deforms and presses against the edge wall of the recess to provide a seal between the plastic cover and the inverter housing.

14. A low-profile electric pump device, comprising: A transmission housing having a pump portion for pumping fluid within the transmission housing; A motor housing, which is connected to the pump section; An inverter housing having a first side portion connected to the motor housing and a second side portion of the inverter housing having a recess defined by an edge wall; An electronic control unit, the electronic control unit being located within the recess on the second side of the inverter housing; A plastic cap having a periphery sized to cover the recess and seal against the edge wall of the recess; A metal bracket, molded into the plastic cover, the metal bracket having at least one exposed surface, the exposed surface engaging the inverter housing to hold the plastic cover in place on the inverter housing, such that the plastic cover seals and covers the recess at the second side of the electronic control unit and the inverter housing. The packaging outline is defined by a gap point located on the transmission housing, wherein the motor housing, the inverter housing, and the plastic cover are located at a distance within the packaging outline.

15. The low-profile electric pump device according to claim 14, further comprising: The metal support is encapsulated within the plastic cap in a molded, overlay portion, and the at least one exposed surface of the metal support is an arm extending away from the plastic cap and the molded, overlay portion of the metal support, beyond the periphery of the plastic cap. The arm has a fastener protrusion with a hole sized to receive a fastener. The fastener is used to connect the metal bracket and the plastic cover to the motor housing and to hold the plastic cover against the inverter housing in place, such that the plastic cover seals and covers the recess on the second side of the electronic control unit and the inverter housing.

16. The low-profile electric pump device according to claim 15, wherein, The metal support is made of steel.

17. The low-profile electric pump device according to claim 15, wherein, The plastic cap has an inner surface and an outer surface, the outer surface having a first plane, and the arm having a shoulder extending beyond the inner surface, bending away from the plastic cap and forming a fastener protrusion, wherein the orifice of the arm is located at the fastener protrusion, and the fastener protrusion has a second plane parallel to the first plane of the outer surface of the plastic cap.

18. The low-profile electric pump device according to claim 15, wherein, The arm has a shoulder that extends away from the plastic cover and terminates at a fastener protrusion, wherein the orifice of the arm is positioned to penetrate the fastener protrusion.

19. The low-profile electric pump device according to claim 18, wherein, The shoulder and the fastener protrusion have a thickness of 1.5 mm or less.

20. The low-profile electric pump device according to claim 15, wherein, The arm has a thickness of 1.5 mm or less.

21. The low-profile electric pump device according to claim 15, further comprising: in, The fastener has a head and a threaded shaft extending from the head, wherein the threaded shaft has a diameter; A threaded fastener hole is formed in the motor housing, wherein the threaded fastener hole is threaded and mates with the threaded shaft of the fastener to form a threaded connection. The gap orifice in the inverter housing is larger than the diameter of the threaded shaft of the fastener, wherein the threaded shaft passes through the gap orifice of the inverter housing. Wherein, the orifice of the fastener protrusion of the arm is a clearance orifice with a diameter larger than that of the threaded shaft of the fastener, such that the threaded shaft passes through the orifice of the fastener protrusion, and the head of the fastener contacts a portion of the periphery of the orifice of the fastener protrusion such that the head presses against the fastener protrusion, thereby using the threaded connection to hold the plastic cover and the inverter housing against the motor housing.

22. The low-profile electric pump device according to claim 14, wherein, The metal bracket has a shape that conforms to the periphery of the plastic cover and has an exposed surface that extends beyond the periphery of the plastic cover, and the metal bracket is larger than the edge wall of the recess, wherein the metal bracket is extendable such that when the plastic cover is connected to the inverter housing, the exposed surface is shaped between the plastic cover and the edge wall of the recess of the inverter housing to form a press-fit connection.

23. The low-profile electric pump device according to claim 22, wherein, The metal support is made of aluminum.

24. The low-profile electric pump device according to claim 22, wherein, The exposed surface has one or more grooves such that when the plastic cover is attached to the inverter housing, the one or more grooves deform and provide a press-fit connection between the plastic cover and the edge wall of the recess in the inverter housing.

25. The low-profile electric pump device according to claim 22, further comprising: A circumferential groove, the groove being located below the metal bracket, and A rubber gasket is located within the groove, wherein the rubber gasket deforms and presses against the edge wall of the recess to provide a seal between the plastic cover and the inverter housing.

26. The low-profile electric pump device according to claim 22, wherein, The metal bracket has a plurality of teeth and a plurality of recesses surrounding the outer periphery of the metal bracket, the plurality of recesses being spaced apart from each of the plurality of teeth, wherein plastic material for forming the plastic cover is formed in the plurality of recesses to secure the metal bracket to the plastic cover.

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