Stator arrangement for an electric motor, electric motor and method for assembling a stator arrangement

Abstract

Stator arrangement (1, 15) for an electric motor with an outer housing (2) having an aperture, in which a stator package (4) with a stator wound (5) is received, wherein radially protruding busbar terminals (8, 17) are arranged near one axial end of the stator wound (5), wherein a fluid deflection ring (6, 20) is arranged at a position axially further inward than the busbar terminals (8, 17), wherein the busbar terminals (8, 17) extend further radially outwards than an inner circumference of the fluid deflection ring (6, 20), wherein the fluid deflection ring (6, 20) comprises at least two ring segments (9, 12, 16, 19), which are configured to be assembled. In addition, a method for assembling a stator arrangement (1, 15) is proposed.

Description

[0001] Stator arrangement for an electric motor, electric motor and method for assembling a stator arrangement

[0002] The invention relates to a stator arrangement for an electric motor with an outer housing having an aperture, in which a stator package with a stator wound is received, wherein radially protruding busbar terminals are arranged near one axial end of the stator wound.

[0003] Electric machines are increasingly used in electrically driven vehicles or hybrid vehicles. The electric machine is mainly used as an electric motor to drive a wheel or an axle of the vehicle.

[0004] The electric motor is usually mechanically coupled to a gearbox for speed adjustment. In addition, the electric motor is electrically connected to an inverter which generates an alternating voltage, in particular a multi-phase alternating voltage, for operating the electric machine from a direct voltage supplied by a battery.

[0005] The stator of an electric machine has a stator core and stator windings. The rotor lamination stack consists of axially stacked rotor laminations. Some of the rotor laminations have recesses that form pockets for magnets. When a current is applied to the stator windings, an electric rotating field is generated, which causes the rotor to rotate.

[0006] When a stator arrangement is assembled, a stator package with a stator wound is inserted in an outer housing. The stator package is provided with radially protruding busbar terminals near one axial end of the stator wound. A fluid cooled stator is provided with a fluid deflection ring on one axial side to gain enough counter pressure for a cooling fluid. However, a fluid deflection ring cannot be mounted due to the protruding busbar terminals, which are in the way.

[0007] The invention is therefore based on the problem to assemble a stator arrangement comprising a stator wound with radially protruding busbar terminals near one axial end of the stator wound and a fluid deflection ring.

[0008] This problem is solved by a stator arrangement with the features of claim 1 .

[0009] According to the invention, a fluid deflection ring is arranged at a position axially further inward than the busbar terminals, wherein the busbar terminals extend further radially outwards than an inner circumference of the fluid deflection ring, wherein the fluid deflection ring comprises at least two ring segments, which are configured to be assembled The invention is based on the idea that a fluid deflection ring can be mounted after a stator wound has been inserted into an outer housing, provided that the ring comprises at least two separate ring segments which can be assembled after inserting into the outer housing. Dividing the fluid deflection ring into two or more ring segments enables to insert them separately and to assemble them further axially inward than the protruding busbar terminals.

[0010] Preferably, the ring segments for the inventive stator arrangement are provided with form-fit connections, which enable to assemble the at least two ring segments.

[0011] A form-fit connection comprises one ring segment with an undercut and another ring segment with a corresponding opposite shape. Such a form-fit connection has the advantage that the ring segments can be connected without any other connection means like screws, rivets, glue or the like.

[0012] According to a preferred embodiment of the invention the ring segment with the undercut is formed as a T-shape and the other ring segment is formed as a corresponding negative T- shape. such shapes can be manufactured easily. They have a similar shape as a piece of a puzzle.

[0013] In the inventive stator arrangement, it can be envisaged that one ring segment is provided with a radial inner protrusion, which is configured to abut against a protrusion of the outer housing, when the fluid deflection ring is rotated in circumferential direction. The radial inner protrusion ensures that both ring segments have a defined position in the assembled state.

[0014] Preferably, the fluid deflection ring is secured by a circlip, a snap ring, a locking ring or a retaining ring, which is inserted in a circumferential groove of the outer housing. Each of these rings keeps the fluid deflection ring at its position and prevents any its movement.

[0015] In the invention it is particularly preferred that the fluid deflection ring comprises spray holes, which are arranged in circumferential direction along its inner circumference. Through the spray holes cooling fluid is sprayed onto the stator wound, so that heat is dissipated from the stator wound

[0016] The fluid deflection ring of the inventive stator arrangement can be provided with radial struts on one or on both surfaces. Preferably, the fluid deflection ring comprises holes for fixing elements, in particular for screws.

[0017] The fixing elements enable clamping the fluid deflection ring in axial direction.

[0018] The invention further relates to an electric motor, comprising a stator arrangement as described and a rotor which is received in the stator package.

[0019] In addition, the invention relates to a method for assembling a stator arrangement, comprising the following steps: inserting a stator package with a stator wound into an aperture of an outer housing, wherein radially protruding busbar terminals are arranged near one axial end of the stator wound, inserting a first ring segment of a fluid deflection ring in axial direction at a position axially further inward than the busbar terminals at a circumferential position, where the first ring segment does not contact the busbar terminals, turning the first ring segment in circumferential direction, until no busbar terminals are present in a gap between both ends of the first ring segment, and inserting a second ring segment and assembling it with the first ring segment to form a closed fluid deflection ring.

[0020] The invention is explained by means of a preferred example with reference to the drawings. The drawings are schematic and show:

[0021] Fig. 1 a perspective view of an inventive stator arrangement;

[0022] Fig. 2 a view of the stator arrangement of Fig. 1 along the axial direction;

[0023] Fig. 3 the stator arrangement with turned first ring segment;

[0024] Fig. 4 the stator arrangement after the assembly;

[0025] Fig. 5 a perspective view of a fluid deflection ring;

[0026] Fig. 6 a second embodiment of an inventive stator arrangement;

[0027] Fig. 7 a detail of a first ring segment;

[0028] Fig. 8 the stator arrangement of Fig. 6 with turned first ring segment;

[0029] Fig. 9 the stator arrangement with a circlip; and Fig. 10 the stator arrangement with a retaining ring.

[0030] Fig. 1 is a perspective view and shows a stator arrangement 1 for an electric motor with an outer housing 2, which is pot-shaped. The outer housing 2 comprises an aperture 3, in which a stator package 4 with a stator wound 5 is received. The stator package 4 is shaped as a hollow cylinder, which is provided with stator wounds 5 at both axial ends.

[0031] The stator arrangement 1 is provided with a cooling means, whereby cooling fluid is supplied through an inlet (not shown). The cooling fluid is conveyed through the stator arrangement 1 and dissipates heat from the stator package 4, until it leaves the stator arrangement 1 through an outlet (not shown). A fluid deflection ring 6 is positioned at the outer axial side of the stator package 4 and fixed by screws 7. Within the outer housing 2 cooling fluid is sprayed against the fluid deflection ring 6. At its inner circumference the fluid deflection ring 6 is provided with through holes, through which cooling fluid is sprayed onto the stator wound 5.

[0032] Fig. 2 is a view of the stator arrangement 1 approximately along the axial direction. The stator package 4 is provided with radially protruding busbar terminals 8, which are arranged at the axial end of the stator package 4 near the open end of the outer housing 2, approximately at the same axial position as the stator wound 5. During assembly of the stator arrangement 1 the problem occurs that a conventional fluid deflection ring cannot be mounted, as the busbar terminals 8 protrude radially outwards, whereas the fluid detection ring must be positioned further axially inwards.

[0033] In order to avoid this problem, the fluid deflection ring 6 comprises a first ring segment 9 and a second ring segment, which will be explained later. The first ring segment 9 is provided with form-fit connections 10 at both ends. Each form-fit connection 10 comprises an undercut, which can be assembled with a corresponding opposite shape of the second ring segment. In this embodiment the form-fit connection 10 is formed as a T-shape.

[0034] When the stator arrangement 1 is assembled, the stator package 4 with the stator wound 5 is inserted into the aperture 3 of the outer housing 2. Subsequently, the first ring segment 9 of the fluid deflection ring 6 is inserted in axial direction of the outer housing 2 and positioned axially further inwards than the busbar terminals 8. The first ring segment 9 is then turned in circumferential direction, so that the first ring segment 9 does not contact the busbar terminals 8. Turning the first ring segment 9 is possible because it is positioned further axially inwards than the busbar terminals 8. The next step of the assembly process is shown in Fig. 3. It can be seen, that the first ring segment 9 has been turned clockwise in circumferential direction for about 90°, as indicated by the arrow. In this state the busbar terminals 8 are no longer present in a gap 11 between both ends of the first ring segment 9. A second ring segment 12 can then be inserted and assembled with the first ring segment 9.

[0035] Fig. 4 shows the final state, after attaching the second ring segment 12. The second ring segment 12 has a negative T-shape, which corresponds to the positive T-shape of the first ring segment 9. Both form-fit connections 10 are assembled like puzzle pieces, that hold together tightly. The fluid deflection ring 6 comprising the first ring segment 9 and the second ring segment 12 is secured by screws 7 as shown in Fig. 1. A rotor can subsequently be inserted in the stator arrangement 1 to form an electric motor.

[0036] In Fig. 5 the fluid deflection ring 6 is shown comprising the first ring segment 9 and the second ring segment 12. Both ring segments 9, 12 comprise radial struts 13 on both sides. Along the inner circumference of the ring segments 9, 12 spray holes 14 are arranged. The function of the fluid deflection ring 6 is to gain a certain amount of counter pressure for cooling fluid which is supplied under pressure into the outer housing 2, so that it sprays against the inner surface of the fluid deflection ring 6. Cooling fluid which is injected from the spray holes 14 is sprayed onto the stator wound 5. Thereby, heat is dissipated from the stator wound 5.

[0037] Fig. 6 shows a second embodiment of a stator arrangement 15, which has a similar structure as the stator arrangement 1 . Therefore, identical components are not explained in detail again. In accordance with the first embodiment the stator arrangement 15 comprises the outer housing 2, in which the stator package 4 with the stator wound 5 is received. A first ring segment 16 of a fluid deflection ring is inserted in the opening of the outer housing 2. A gap is formed between both ends of the first ring segment 16 in circumferential direction. The first ring segment 16 is positioned in circumferential direction such that it does not contact busbar terminals 17. The first ring segment 16 is provided with an inner protrusion. When the first ring segment 16 is turned clockwise, the inner protrusion abuts against a protrusion of the outer housing 2, so that the first ring segment 16 is in a predefined position.

[0038] Fig. 7 shows a detail of the first ring segment 16 with the protrusion 18 at inner side. Spray holes 14 are arranged in two rows in circumferential direction of the first ring segment 16.

[0039] Fig. 8 shows the stator arrangement 15 after the first ring segment 16 has been turned until its protrusion 18 abuts against the outer housing 2. In this state a second ring segment 19 is connected to the first ring segment 16 is in the first embodiment. For simplification the form-fit connections of both ring segments 16, 19 is not depicted in Fig. 8. The assembled ring segments 16, 19 form a fluid deflection ring 20. Fig. 9 shows the stator arrangement 15 after a circlip 21 has been attached for securing the fluid deflection ring 20 radially. The circlip 21 is received in a circumferential groove near the opening of the outer housing 2. The circlip 21 serves as a lock for the fluid deflection ring 20, which is thereby held in place. Fig. 10 shows an alternative embodiment, in which a retaining ring 22 is used. The retaining ring 22 is a spring elastic ring, which is partly received in the circumferential groove in the outer housing 2.

[0040] List of reference numbers

[0041] 1 stator arrangement

[0042] 2 outer housing

[0043] 3 aperture

[0044] 4 stator package

[0045] 5 stator wound

[0046] 6 fluid deflection ring

[0047] 7 screw

[0048] 8 busbar terminals

[0049] 9 first ring segment

[0050] 10 form-fit connection

[0051] 11 gap

[0052] 12 second ring segment

[0053] 13 strut

[0054] 14 spray hole

[0055] 15 stator arrangement

[0056] 16 first ring segment

[0057] 17 busbar terminals

[0058] 18 protrusion

[0059] 19 second ring segment

[0060] 20 fluid deflection ring

[0061] 21 circlip

[0062] 22 retaining ring

Claims

Claims1. Stator arrangement (1 , 15) for an electric motor with an outer housing (2) having an aperture, in which a stator package (4) with a stator wound (5) is received, wherein radially protruding busbar terminals (8, 17) are arranged near one axial end of the stator wound (5), characterized in that a fluid deflection ring (6, 20) is arranged at a position axially further inward than the busbar terminals (8, 17), wherein the busbar terminals (8, 17) extend further radially outwards than an inner circumference of the fluid deflection ring (6, 20), wherein the fluid deflection ring (6, 20) comprises at least two ring segments (9, 12, 16, 19), which are configured to be assembled.

2. Stator arrangement according to claim 1 , wherein the ring segments (9, 12, 16, 19) are provided with form-fit connections (10).

3. Stator arrangement according to claim 1 or 2, wherein a form-fit connection (10) comprises one ring segment (9) with an undercut and another ring segment (12) with a corresponding opposite shape.

4. Stator arrangement according to claim 3, wherein the ring segment (9) with the undercut is formed as a T-shape and the other ring segment (12) is formed as a corresponding negative T-shape.

5. Stator arrangement according to any of the preceding claims, wherein one ring segment (16) is provided with a radial inner protrusion (18), which is configured to abut against a protrusion of the outer housing (2), when the fluid deflection ring (20) is rotated in circumferential direction.

6. Stator arrangement according to any of the preceding claims, wherein the fluid deflection ring (6, 20) is secured by a circlip (21 ), a snap ring, a locking ring or a retaining ring (22), which is inserted in a circumferential groove of the outer housing (2).

7. Stator arrangement according to any of the preceding claims, wherein the fluid deflection ring (6, 20) comprises spray holes (14), which are arranged in circumferential direction along its inner circumference.

8. Stator arrangement according to any of the preceding claims, wherein the fluid deflection ring (6) comprises radial struts (13) on one or on both surfaces.

9. Stator arrangement according to any of the preceding claims, wherein the fluid deflection ring (6) comprises holes for fixing elements, in particular for screws (7).

10. Electric motor, comprising a stator arrangement (1 , 15) according to any of claims 1 to9 and a rotor which is received in the stator package (4).11 . Method for assembling a stator arrangement (1 , 15), comprising the following steps:- inserting a stator package (4) with a stator wound (5) into an aperture of an outer housing (2), wherein radially protruding busbar terminals (8) are arranged near one axial end of the stator wound (5),- inserting a first ring segment (9, 16) of a fluid deflection ring (6, 20) in axial direction at a position axially further inward than the busbar terminals (8) at a circumferential position, where the first ring segment (9, 16) does not contact the busbar terminals (8), - turning the first ring segment (9, 16) in circumferential direction, until no busbar terminals (8) are present in a gap (1 1 ) between both ends of the first ring segment (9, 16), and- inserting a second ring segment (12, 19) and assembling it with the first ring segment (9, 16) to form a closed fluid deflection ring (6, 20).

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