Electric pump and use of electric pump

Abstract

The invention relates to an electric pump and to the use of an electric pump, comprising a motor housing (3), a stator (2) and a rotor assembly (33), the stator (2) being located in the motor housing (3), the stator (2) circumferentially surrounding the rotor assembly (33), the motor housing (3) being subjected to a vacuum impregnation treatment and the rotor assembly (33) being penetrated by a stationary operating shaft (32), the operating shaft (32) is pressed into the motor housing (3) or into a reinforcing disk (15, 40) connected to the motor housing (3).

Description

Technical Field

[0001] The present invention relates to an electric pump having the features of the preamble of embodiment 1 and the use of said electric pump as a coolant pump in a vehicle. Background Technology

[0002] Electric coolant pumps can be used in vehicles ranging from those with internal combustion engines to hybrid and electric vehicles, and even those with fuel cell drives. These electric coolant pumps optimize thermal management through their cooling effect.

[0003] For these applications, it is known to use electric coolant pumps with a spalttopf (split-head). Typically, a plastic spalttopf with a wall thickness of 1 mm is used. This results in a large magnetic air gap. Due to the resulting magnetic field losses, the motor must be larger and more expensive to manufacture compared to motors with smaller air gaps. Furthermore, the plastic spalttopf acts as an insulator and prevents heat loss from the stator into the coolant. Spalttopf with a metal having good thermal conductivity is also known, but this introduces significant eddy current losses.

[0004] The stator of the motor for the electric coolant pump can be formed, for example, by overmolding. However, overmolding has the disadvantage of requiring high mold costs, especially when using multiple different stack heights.

[0005] In the manufacture of electric motors, impregnation of the stator is a common process used to stabilize the windings and improve heat dissipation from the stator to the cooling medium. The impregnating agent also enters the cavities of the stator, but also coats the stator and alters its dimensions. In addition, during curing, droplet bumps can form, which may, for example, make it difficult to press the stator into the housing. Summary of the Invention

[0006] The object of this invention is to provide an electric pump that can be manufactured in a particularly simple and economical manner.

[0007] The objective is achieved by an electric pump having the features of Scheme 1.

[0008] Accordingly, an electric pump is provided, the electric pump having a motor housing, a stator and a rotor assembly, the stator being located in the motor housing and circumferentially surrounding the rotor assembly, wherein the motor housing is at least partially vacuum impregnated, and the rotor assembly is penetrated by a fixed running shaft, the running shaft being pressed into the motor housing or pressed into a reinforcing disc connected to the motor housing.

[0009] Press-fitting the axial motor housing is a relatively stable installation process that allows for larger tolerances and higher press-fit forces. The motor housing is vacuum impregnated, providing corrosion protection against external and internal corrosive influences, and allows the use of economical, uncoated materials. Preferably, the motor housing is deep-drawn, particularly from sheet steel, and thus can be manufactured particularly economically without the need for further machining.

[0010] A particular advantage is that the motor housing and the stator are vacuum impregnated as a whole. Because the entire assembly is vacuum impregnated, problems arising from the uncertain dimensions of the impregnating agent coating structure when installing the stator into the housing, as seen in stator impregnation, are avoided. Conventional stator overmolding can be omitted. However, when used in electric coolant pumps, the stator with wound coils remains electrically insulated relative to the coolant. Furthermore, the impregnating agent can bond the stator windings to the existing laminations, resulting in improvements in acoustic characteristics and heat dissipation. Moreover, vacuum impregnation of the entire assembly allows for the stator to be securely fixed within the housing. Furthermore, the adhesive connection between the stator and the housing reinforces the thin-walled housing and avoids the use of thick-walled and heavy housings.

[0011] Preferably, the stator is fixed to the housing by welding, riveting, or press-fitting. During riveting, the housing can be pressed into the grooves of the stator's insulating components from the outside.

[0012] Preferably, the pump has a rotor assembly rotatably supported on a running shaft inside the stator, wherein the rotor assembly includes an impeller and a magnetic rotor. The impeller may be integrally formed with a rotor adapter, on which rotor magnets, particularly toroidal ferromagnets, are fixed. The rotor adapter preferably has a receiving portion at its end away from the support, into which an axial thrust washer is pressed. The spiral housing is preferably fixed to the motor housing, for example, by a locating sleeve. The motor housing may be configured to be surrounded by a plug-in housing. The plug-in housing is preferably a deep-drawn aluminum housing. A circuit board may be housed within the plug-in housing. The circuit board is preferably connected to the outside of the bottom of the housing via a thermal pad, thereby allowing for good heat dissipation. The ends of the winding wires leading from inside the motor housing are preferably electrically connected to the circuit board. The plug-in housing preferably has a plug-in geometry and electrical contacts located within the plug-in geometry, which are connected to the circuit board.

[0013] Preferably, the stator has multiple laminations, and a single stator core segment is formed by multiple said laminations, including a coil of winding wire wound around the stator core. The ends of the winding wires are preferably led out from the bottom of the housing through an opening for direct contact with the circuit board. The bottom of the housing preferably has an inlet ramp for orienting the ends of the winding wires. In this case, a busbar unit can be omitted.

[0014] In one embodiment, the housing is bowl-shaped with a bottom and cylindrical peripheral walls, and the bottom has a central recess with a through opening, wherein the running shaft is pressed into a support formed through the recess.

[0015] In another embodiment, the housing is bowl-shaped with a bottom and cylindrical peripheral walls. The bottom has a central through-hole, wherein a reinforcing plate is provided on the outer side of the bottom, and the reinforcing plate extends into the opening and into the interior of the housing via an annular protrusion. The inner side of the annular protrusion forms a support, into which the running shaft is pressed. The bottom is reinforced by the reinforcing plate, and the reinforcing plate bears the force generated when the running shaft is pressed in.

[0016] In another embodiment, the housing is bowl-shaped with a bottom and cylindrical peripheral walls, wherein the bottom has a central through-hole, and a reinforcing disc is provided on the inner side of the bottom, the reinforcing disc having an inwardly extending annular protrusion, and wherein the inner side of the annular protrusion forms a support into which the running shaft is pressed. In this case, the bottom is also reinforced by the reinforcing disc, and the reinforcing disc bears the force generated when the running shaft is pressed in.

[0017] The reinforcing disk can be a sintered disk made of porous material or an aluminum disk.

[0018] Preferably, the reinforcing disc has a through opening at the center of the annular protrusion, and this opening is specifically configured to correspond to the opening at the bottom.

[0019] A particular advantage is that the support remains free of impregnating agent. At this point, the pressing is then completed with greater precision and process reliability.

[0020] The magnetic gap can be less than 0.6 mm, especially about 0.5 mm, thereby allowing the motor and, consequently, the electric pump to be configured particularly compactly. A separate pump head can be eliminated.

[0021] Preferably, the housing and stator are grounded together by contacting the running shaft. This provides effective protection against electrostatic discharge (ESD) and electromagnetic radiation (EM) from the motor.

[0022] The impregnating agent is preferably an epoxy-familie resin. The impregnated layer is preferably less than 0.04 mm, thereby achieving the smallest possible magnetic air gap between the stator and rotor.

[0023] Furthermore, the aforementioned electric pump is used as a coolant pump in vehicles, preferably in battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), internal combustion engine vehicles (ICEs), and / or fuel cell vehicles (FCVs). The electric coolant pump can optimize thermal management through its cooling effect.

[0024] The coolant pump preferably has a power range of 50W to 600W, particularly between 100W and 300W. The pump is preferably a 12V pump. Attached Figure Description

[0025] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Identical components or components having the same function are marked with the same reference numerals. Wherein: Figure 1 : A longitudinal sectional view of the assembly during vacuum impregnation. The assembly includes a stator and a housing. Figure 2 Longitudinal sectional view of the component with the plug. Figure 3 Detailed diagram of the cable conduction structure (Drahtdurchzug) passing through the housing. Figure 4 Longitudinal sectional view of an electric coolant pump. Figure 5a and Figure 5b : Figure 5a This is a longitudinal sectional view of another embodiment of the component, which includes a stator and a housing, and Figure 5b This is a top view of the stator and its housing, and Figure 6 Longitudinal sectional view of an electric coolant pump, the electric coolant pump having Figure 5a and Figure 5b The components shown in the image. Detailed Implementation

[0026] exist Figure 1The vacuum impregnation apparatus 4 shows component 1, which includes a stator 2 and a housing 3. The housing 3 is bowl-shaped and constructed with a bottom 5 and cylindrical peripheral walls 6. A through-hole 7 is centrally located at the bottom 5. The peripheral walls 6 are flanged outwards at their ends away from the bottom. The flange 8 forms a flange. The housing 3 of the motor is preferably made of thin-walled sheet metal, particularly steel sheet, and formed by deep drawing. Sheet metal housings offer advantages such as similar thermal expansion to the laminations 9 of the stator 2, higher precision, better electromagnetic shielding, better thermal conductivity, higher strength, and a lower CO2 footprint.

[0027] However, the casing 3 can also be made of inexpensive plastic. Plastic casings offer the advantage of lower material costs because plastics that are not resistant to coolant can also be used.

[0028] The stator 2 has a lamination group 9 comprising a plurality of identical laminations 10, which are manufactured by stamping (blanking) and stacked equidistantly to form the lamination group 9. The stacked laminations 10, which are insulated from each other on their mating sides, are mechanically and electrically interconnected. The stacked laminations 10 have grooves (not shown here) on their inner edges for receiving windings 11. An end 12 of a winding 11 extends outward through a through opening 13 in the bottom 5 of the housing 3. The opening 13 has an inlet ramp on its inner side, through which the winding end 12 is oriented as it is introduced into the opening 13. The winding topology of the stator 2 predetermines the number of winding ends. Preferably, each motor phase has one winding end.

[0029] In the embodiment shown in component 1, on the lower side 14 of the bottom 5 (in Figure 1 A reinforcing disc 15 is provided at the upper center, preferably a sintered disc made of porous material or an aluminum disc. An opening 16 with a raised edge 17 is provided in the center of the reinforcing disc 15, which constitutes a support for a shaft (not shown). The edge 17 is configured such that it is embedded in the opening 7 of the bottom 5 of the housing 3 and extends into the interior of the housing 3. Furthermore, an opening 18 is provided in the reinforcing disc 15 for guiding the winding end 12 through. During assembly, the winding end 12 (phase wire) is first passed through the openings 13 and 18 of the bottom 5 of the housing and the reinforcing disc 15, and its position is correctly oriented at this point. Thus, a separate busbar is eliminated in further wiring distribution. The winding end 12 is oriented parallel to the longitudinal axis of the assembly 2.

[0030] Before vacuum impregnation, the stator 2 is fixed to the inner side of the peripheral wall 6 of the housing 3. The wound stator 2 is pushed to the stop 19 and fixed in the form of an transition fit. This can be achieved by welding or by inserting the stator 2 between radially inward protruding ridges of the peripheral wall 6. It is also conceivable that the stator is riveted to the housing. This fixing scheme will be described in detail below.

[0031] The vacuum impregnation apparatus 4 has a base plate 20 on which the assembly 2 is placed via a flange of the housing 3. The base plate 20 has an opening 21 that matches the inner diameter of the housing 3 in the region of the peripheral wall 6. The base plate 20, together with a cover plate 22, forms an impregnation chamber 23. Impregnating agent is introduced into the impregnation chamber 23 from a storage container located below the base plate 20, as schematically shown by arrows. The opening 21 of the base plate 20 serves as an inlet. An outlet 24 is provided in the cover plate 22 surrounding the assembly 1. A device (e.g., a vacuum pump system), not shown here, for evacuating the impregnation chamber, ensures the achievement of the necessary negative pressure relative to ambient pressure. This is preferably achieved by continuously evacuating the impregnation chamber 23 during the impregnation process. Alternatively, the impregnation chamber 23 may be connected to the device for evacuating the impregnation chamber 23 via a valve only when needed (e.g., when a predetermined maximum pressure value is exceeded), and otherwise disconnected from the device. The valve is preferably equipped with a corresponding regulating device for opening or closing the valve in relation to pressure.

[0032] The impregnating agent is preferably an epoxy resin. The surface of the vacuum impregnation device 4 that comes into contact with the resin is made of a plastic (PE, PA, PP, PC, etc.) that does not adhere to the resin. Conversely, the component 1 is completely wetted by the impregnating agent. Due to capillary action, the impregnating agent can slowly penetrate even through extremely narrow gaps, thereby achieving the following effects: - Glue the stator 2 to the housing 3. - Glue the laminate 10 to the winding 11 of the stator 2. - Adhere the reinforcing plate 15 to the housing 3. - Seal the openings 13 and 18 used to guide the ends of the winding wires through. - Corrosion protection and electrical insulation are achieved through coatings on all surfaces.

[0033] During vacuum impregnation, the vacuum impregnation apparatus 4 is preferably operated between 40 mbar and 60 mbar for 11 to 18 minutes. Thereafter, curing is carried out at ambient pressure and at a temperature between 150°C and 180°C for at least 2 hours, particularly at least 3.5 hours.

[0034] By vacuum impregnating the entire component 1, unavoidable droplet bumps are formed at locations where the droplet bumps will not cause interference.

[0035] Figure 2 Component 1 is shown in the vacuum impregnation apparatus 4. Component 1 includes a stator 2 and a housing 3. Figure 1 In a different implementation, the housing 3 has a centrally located recess 25 at its bottom 5, which forms a support for the shaft. An opening 26 is provided at the center of the recess 25 at the bottom 5. To allow for simple and precise pressing of the shaft into the recess 25, a plug 27, preferably made of rubber, is used to seal the recess 25 during vacuum impregnation. This prevents the impregnating agent from entering the recess 25 and preserves the bore size for pressing the shaft into this area, or rather, the precise geometry from the deep-drawing process. Thus, a precise press-fit connection for a shaft (not shown) can be achieved.

[0036] and Figure 1 In different implementations, the reinforcing disc 15 is constructed to be flat and circumferentially surrounds the recess 25, so that the reinforcing disc 15 can withstand the force generated when the shaft is pressed into the recess.

[0037] exist Figure 3 The diagram shows a detailed view of the opening 13 in the housing 3 and the end 12 of the winding wire being guided through it. The aforementioned guide ramp 28 is formed on the inside and protrudes inward from the housing 3 around the opening 13. The depth of the guide ramp 28 approximately corresponds to the height of the protrusion 29. On the outside, a recess 30 is provided in the housing 3 around the opening 13, in which the impregnating agent collects during vacuum impregnation, thereby forming an impregnating agent zone during hardening, thus ensuring a good seal.

[0038] Figure 4 A portion of an exemplary electric coolant pump 31 is shown, comprising a housing 3 and a stator 2. An operating shaft 32 is pressed into a support at the center of the bottom 5 of the housing 3. Pressing the operating shaft into the motor housing with a shorter length is a more stable installation process that allows for larger tolerances and higher pressing forces.

[0039] Rotor assembly 33 is rotatably supported on the running shaft 32. Stator 2 thus circumferentially surrounds rotor assembly 33. Rotor assembly 33 includes an impeller 34 and a magnetic rotor 35, the magnetic rotor 35 having an outerly embedded annular ferromagnetic body 36. Magnetic rotor 35 is rotatably supported on the running shaft 32. Magnetic rotor 35 and impeller are integrally formed. Magnetic rotor 35 has a receiving portion at the end remote from the support, into which an axial thrust washer is pressed.

[0040] The motor housing 3, the spiral housing (not shown), and the plug-in housing 37 are oriented relative to each other via a positioning sleeve 38. The plug-in housing 37 is preferably a deep-drawn aluminum housing. A circuit board 39 and an assembly 1 with a reinforcing disc 15 are provided within the plug-in housing 37. The circuit board 39 is connected to the outer side of the bottom of the housing via a thermal pad, thereby allowing for good heat dissipation.

[0041] The running shaft is preferably metallic and can be used to effectively ground the stator. For example, regarding... Figure 2 As described, when the plug is used in vacuum impregnation, the recess remains conductive, which is advantageous for electromagnetic shielding, possible overall grounding, and thermal conductivity. Thus, by forming a grounding pin (not shown) on the running shaft 32, the housing 3, stator 2, and running shaft 32 can be grounded together, thereby achieving effective protection against electrostatic discharge (ESD) and electromagnetic (EM) radiation from the motor.

[0042] exist Figure 5a and Figure 5b Another possible implementation is shown below. Unlike the previous implementations, such as... Figure 5a As shown, a reinforcing disc 40 is provided inside the housing 3. The reinforcing disc 40 is fitted to the bottom 5 of the housing 3. The reinforcing disc 40 has a central opening 41 and a raised edge 42 surrounding the opening 41, which extends inward into the housing 3, forming a support for a shaft (not shown). The opening 41 completely coincides with the opening 7 of the bottom 5 of the housing 3. The reinforcing disc 40 additionally has an opening 43 for guiding the winding wire end 12 through. The winding wire end 12 is oriented parallel to the longitudinal axis of the assembly by a guide ramp 44 formed in the opening 43. The reinforcing disc 40 is held in the housing 3 by radial riveting. The riveting is schematically shown by arrows. The housing 3 and the reinforcing disc 40 located in the housing are riveted together from the outside by punches.

[0043] In the illustrated embodiment, the stator 2 is supported on a positioning device 45, and the housing 3 is placed on top of and also on the positioning device 45. The positioning device 45 has a planar surface 46 and an annular protrusion 47 on the surface. To position the stator 2, the stator is placed on the protrusion 47, and the housing 3 is placed on the planar surface 46. Thus, the depth of the stator 2 within the housing 3 is defined by the height of the protrusion 47. After the stator 2 and housing 3 are placed on the positioning device 45, the two components 2 and 3 are radially riveted together from the outside using punches (schematically shown in...). Figure 5a (As shown on the right).

[0044] like Figure 5bAs shown, the stator 2 has multiple stator core segments 48, each correspondingly assigned an insulator 49. A coil 50, schematically shown, is wound around the core segments 48 constituting the armature and the insulators 49. The coil 50 is made of winding wire. The winding topology is not shown in the illustration. Each insulator 49 has a longitudinally extending slot 51 at the center of its respective stator core segment, into which the housing 3 is pressed during riveting (schematically indicated by arrows). This securely connects the housing 3 to the stator 2 before vacuum impregnation.

[0045] exist Figure 6 The image shows a cross-sectional view of a coolant pump 31 with component 1, which includes a stator 2 and a housing 3. (See also: For...) Figure 5a and Figure 5b As described, the stator 2 is riveted to the housing 3 and the reinforcing disc 40 is fitted into the housing 3. As previously described, assembly 1 is surrounded by resin by vacuum impregnation. The running shaft 32 is non-rotatably connected to the housing 3 and thus indirectly to the stator 2. The rotor assembly 33 is rotatably supported on the running shaft 32. The rotor assembly 33 includes a rotor adapter 52 that circumferentially surrounds the running shaft 32 and has an open impeller 53 at one end. A magnetic rotor 54 is mounted on the outside of the rotor adapter 52. The magnetic rotor 54 is securely screwed onto the rotor adapter 52. The motor housing 3 may optionally be surrounded by a housing 55 (not shown here).

Claims

1. An electric pump having a motor housing (3), a stator (2), and a rotor assembly (33), the stator (2) being located within the motor housing (3) and circumferentially surrounding the rotor assembly (33), characterized in that, The motor housing (3) is vacuum impregnated, and the rotor assembly (33) is penetrated by a fixed running shaft (32), which is pressed into the motor housing (3) or into a reinforcing disc (15, 40) connected to the motor housing (3).

2. The electric pump according to claim 1, characterized in that, The motor housing (3) is made of steel plate by deep drawing.

3. The electric pump according to claim 2, characterized in that, The motor housing (3) and the stator (2) are vacuum impregnated as components (1).

4. The electric pump according to any one of the preceding claims, characterized in that, The rotor assembly (33) is rotatably supported inside the stator (2) on the running shaft (32), and the rotor assembly (33) includes an impeller (34) and a magnetic rotor (35).

5. The electric pump according to any one of the preceding claims, characterized in that, The housing (3) is bowl-shaped and has a bottom (5) and a cylindrical peripheral wall (6), and the bottom (5) has a central recess (25) with a through opening (26), and the running shaft (32) is pressed into a support formed through the recess.

6. The electric pump according to any one of the preceding claims, characterized in that, The housing (3) is bowl-shaped and has a bottom (5) and a cylindrical peripheral wall (6). The bottom (5) has a central through opening (7). A reinforcing plate (15) is provided on the outer side of the bottom (5). The reinforcing plate extends into the opening (7) and into the interior of the housing (3) with an annular protrusion (17). A support is formed on the inner side of the annular protrusion (17). The running shaft (32) is pressed into the support.

7. The electric pump according to any one of the preceding claims, characterized in that, The housing (3) is bowl-shaped and has a bottom (5) and a cylindrical peripheral wall (6). The bottom (5) has a central through opening (7). A reinforcing plate (40) is provided on the inner side of the bottom (5). The reinforcing plate (40) has an inwardly extending annular protrusion (42). A support is formed on the inner side of the annular protrusion (42). The running shaft (32) is pressed into the support.

8. The electric pump according to any one of the preceding claims, characterized in that, The reinforcing discs (15, 40) have a through opening at the center of the annular protrusions (17, 42).

9. The electric pump according to any one of the preceding claims, characterized in that, The support of the running shaft (32) remains free of impregnating agent.

10. The electric pump according to any one of the preceding claims, characterized in that, The magnetic gap between the stator (2) and the rotor assembly (33) is less than 0.6 mm.

11. The electric pump according to any one of the preceding claims, characterized in that, By contacting the running shaft (32), the housing (3) and the stator (2) are grounded together.

12. The application of an electric pump, characterized in that, The electric pump (31) is the electric pump (31) according to any one of the preceding claims, used as a coolant pump in a vehicle.

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