Stator of an electric motor
The stator design with a contact adapter and locking contours addresses the issue of unstable terminal contacts in brushless DC motors, enhancing assembly reliability and reducing reject rates by securing terminal contacts against movement and vibration.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- BROSE FAHRZEUGTEILE GMBH & CO KG
- Filing Date
- 2025-11-05
- Publication Date
- 2026-05-15
AI Technical Summary
The interface between terminal contacts and contact elements in electric motors, particularly in brushless DC motors, is prone to movement and vibration due to inadequate securing, leading to manufacturing issues and high reject rates during automated assembly.
A stator design with a contact adapter featuring sockets and fork-shaped contact elements with locking contours, such as backward-facing hooks, secures terminal contacts in place by clamping them into axially accessible contact slots, ensuring stability against axial forces and vibrations.
The solution provides a reliable and secure connection that prevents terminal contacts from slipping out, improving manufacturing efficiency and reducing reject rates by ensuring precise positioning during automated assembly.
Smart Images
Figure EP2025081883_15052026_PF_FP_ABST
Abstract
Description
[0001] Page 1
[0002] 2024 537 WO
[0003] Description
[0004] Stator of an electric motor
[0005] The invention relates to a stator of an electric motor, comprising a number of stator teeth which support coils of a multiphase stator winding, and a contact adapter with sockets and with contact elements inserted therein and with a number of phase or terminal contacts. The invention further relates to an electric motor, in particular an auxiliary unit of a motor vehicle, with such a stator.
[0006] Such an electric motor is designed as a so-called brushless electric motor (brushless DC motor, BLDC motor) with electronic commutation of the motor current. The electric motor, as an electric (three-phase) machine, has a stator and a rotor with several permanent magnets, which is fixed to a rotor shaft. The rotor shaft is rotatably mounted about a rotor axis by means of one or more bearings, with each bearing being mounted in a bearing housing of a bearing shield and / or the bottom of a (cup-shaped) motor housing.
[0007] In an internal rotor motor (internal rotor motor or rotor), the stator, which coaxially surrounds the rotor, has, for example, a stator lamination stack with a number of star-arranged stator teeth. These teeth carry an electric rotating field or stator winding in the form of individual (stator) coils wound from insulating wire. The coils are assigned to individual strands or phases of the electric motor and are interconnected in a predetermined manner, for example, in a star or delta connection. For this purpose, the coils are electrically connected to form a multiphase, in particular three-phase, rotating field or stator winding by means of a preferably ring-shaped connecting element mounted on the stator.Typically, each phase of the rotating field or stator winding, which is electrically offset by 120°, is electrically connected to a terminal contact, which is guided, for example, through a corresponding opening in the end shield. On the side of the connection element or end shield opposite the stator, (motor) electronics are usually arranged to energize the phases of the rotating field or stator winding. The electronics comprise a bridge circuit, provided, for example, by means of a printed circuit board, whereby each of the phase terminals is connected to the electronics.
[0008] The interconnection element, also referred to below as a contact adapter, has a preferably ring-shaped, plastic housing with a number of preferably axially raised pockets for electrically conductive contact elements. To connect the coils, wire sections of the coils or their winding wire to be contacted are inserted into corresponding slots of the preferably cuboid-shaped pockets of the interconnection element or contact adapter and mechanically secured within the pocket by the contact element that can be inserted into the respective pocket.
[0009] The contact elements for the coils or their wire sections are preferably designed as insulation displacement contacts. For this purpose, the contact element has one or more cutting edges which, when inserted into the socket, cut the insulation of the wire section of the coil winding located in the respective slot of the socket in such a way that, when the insulation displacement contact is inserted, a conductor of the winding wire is electrically connected to the contact element via the insulation displacement contact.
[0010] On a longitudinal side axially opposite the insulation displacement contact, the contact element has an axially extending contact slot. A connecting contact, for example a rail or contact section of a busbar (page 3) or a stamped grid, of the interconnection element or contact adapter, serving in particular as a phase connection, is or can be inserted into this contact slot with a clamping connection.
[0011] Due to the geometric constraints, the assembly or implementation of an electrical connection between the terminal contacts or phase connections of the busbars or the stamped grid of the interconnecting element or contact adapter with its contact elements is typically automated or carried out using a so-called blind assembly process. The problem here is that the interface between the terminal contact or busbar or contact section serving as a phase connection and the contact element of the interconnecting element (contact adapter) seated in the respective socket cannot absorb axial forces, meaning that the contact is not, or at least not sufficiently, secured against movement or vibration.
[0012] There is also a risk that the respective phase or terminal contact on the side of the component facing away from the stator or the wiring element or contact adapter of the electric motor—for example, on the pump block of an electrically driven brake booster as an auxiliary unit of the vehicle—will not be properly contacted with a (connection) plug. To ensure collision-free contact between the respective phase or terminal contact and the (customer-supplied) connector during automated blind assembly, precise positioning of the phase or terminal contacts (customer contacts) is desirable. However, the necessary positioning accuracy for proper plug contact is often problematic in terms of manufacturability due to the (axial) length of the phase or terminal contacts, which can lead to an undesirably high reject rate.
[0013] The invention is based on the objective of specifying a particularly suitable stator for an electric motor. Preferably, a particularly suitable contact, especially one reliably secured against (micro-)movements, is to be specified at an interface between a terminal contact (which also serves as a phase connection) and a contact element seated in a socket of a wiring element or contact adapter. Furthermore, an electric motor, in particular an auxiliary unit of a motor vehicle, with such a stator is to be specified.
[0014] With regard to the stator, this problem is solved according to the invention by the features of claim 1, and with regard to the electric motor by the features of claim 10. Advantageous further developments and embodiments are the subject of the dependent claims.
[0015] The stator, designed and configured for an electric motor, particularly an internal rotor motor, has a number of stator teeth oriented radially concentrically to a central axis (motor or rotor axis), which support coils of a multiphase stator winding, and a contact adapter. The contact adapter has a number of sockets into which contact elements with at least one insulation displacement contact for electrically connecting coil sections of interconnected coils are inserted or can be inserted. The contact adapter, preferably annular, has a number of connection contacts corresponding to the number of phases of the stator winding.
[0016] The respective contact element, particularly fork-shaped, has a contact slot into which the associated terminal contact is inserted or can be inserted in a clamping manner, the contact slot being axially accessible with respect to the central axis. The terminal contact has a locking contour that anchors the terminal contact in the associated socket. The contact slot of the respective contact element is suitably arranged on the axially opposite side of the insulation displacement contact, in particular between two insulation displacement contacts spaced apart from each other.
[0017] The contact adapter advantageously features a ring-shaped housing, particularly a plastic housing. The sockets (page 5) are axially (i.e., in the axial direction) molded onto this housing. Each socket has radially opposite slots that align with the contact slot of the contact element inserted in the socket.
[0018] In a suitable embodiment, the locking contour is designed as at least one hook facing backwards with respect to the insertion direction of the connection contact. In other words, the locking contour is designed as a barb that is positioned backwards on the connection contact and thereby prevents the connection contact from being pulled out or sliding out of the corresponding socket of the connection adapter. The locking contour can be formed from several hooks, for example in a Christmas tree shape and / or arrangement. Each hook is suitably designed in the manner of a locking hook.
[0019] Advantageously, each pocket of the preferably (circular) annular contact adapter or its housing has intersecting or cross-shaped pocket sections. A first pocket section runs circumferentially or tangentially to the contact adapter, while a second pocket section, preferably centrally intersecting the first pocket section (with respect to the central axis), is oriented radially. The first pocket section serves to receive the contact element. The connecting contact with the locking contour is inserted or can be inserted into the second pocket section, in which the contact slot of the contact element is located.In other words, the connecting contact having the locking contour is inserted into the second pocket section, which runs transversely to the first pocket section, and there into the contact slot of the contact element, making contact with the contact element, whereby the locking contour hooks or latches in the plug pocket or in the second pocket section.
[0020] Particularly advantageous is the at least one of the contact adapter's pockets, which receives the contact connection with the locking contour, in the area of page 6.
[0021] The contact slot of the contact element is closed. Additionally or alternatively, this socket has a wall section on the outer side (of the socket) facing away from the contact slot of the contact element seated in this socket, extending in the insertion direction of the connecting contact, into which the locking contour engages or cuts by deforming.
[0022] Advantageously, each connection contact is molded onto a busbar extending circumferentially around the contact adapter. It is particularly advantageous for the connection contact or busbar to be embedded in or encased in a plastic overmolding as electrical insulation. Suitablely, the connection contacts protrude from this plastic overmolding or insulation at one end, and contact terminals, particularly for a connector, protrude from the other, especially axially opposite, end.
[0023] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing shows:
[0024] Fig. 1 shows a perspective view of an electric motor of an auxiliary unit of a motor vehicle, with a pot-shaped motor housing and a bearing shield, as well as phase or connection contacts oriented parallel to a central axis (motor or rotor axis).
[0025] Fig. 2 shows a perspective view of a stator with the phase or connection contacts in plug pockets of a wiring housing of the connection adapter in a plastic overmolding,
[0026] Fig. 3 shows an exploded view of the stator equipped with coils of a stator winding and the interconnection housing as well as contact elements and the phase or connection contacts of the contact adapter, which are partially molded onto busbars.
[0027] Fig. 4 shows a perspective view of the stator according to Fig. 2 with the contacted terminals without plastic overmolding, page 7
[0028] Fig. 5 shows a partial perspective view of one of the plug pockets with the contact element of the contact adapter inserted therein, looking towards a contact slot of the contact element in a laterally closed pocket section of the plug pocket.
[0029] Fig. 6 shows a partial perspective exploded view of the plug pocket with inserted contact element and the connection section of the phase or connection contact positioned above the contact slot in the plugging direction, with backward-facing barbs as a locking contour in relation to the plugging direction.
[0030] Fig. 7 shows, in partial transparency, the plug pocket with the inserted contact element and the locking contour of the connection contact anchored in the plug pocket, and
[0031] Fig. 8 shows a sectional view along the line VIII-III in Fig. 7, the phase or connection contact anchored in the socket.
[0032] Corresponding parts are marked with the same reference symbols in all figures.
[0033] Figure 1 shows an electric motor 1 comprising a pot-shaped motor housing 2, which is closed by a bearing shield 3. A helical gear 4, in this exemplary embodiment, projects from the bearing shield 3 and is fixed against rotation or shaft movement on a rotor or motor shaft 6 that runs concentrically to a central axis (motor or rotor axis) 5. Furthermore, three phase or connection contacts 7, oriented parallel to the axis 5, extend from the bearing shield 3 through a through-opening 3a in this exemplary embodiment. The axial and radial directions relative to the axis 5 are designated A and R, respectively, in Figure 1.
[0034] With reference to Figures 2 to 4, the electric motor 1 comprises a hollow cylindrical stator 8 arranged in the motor housing 2. Within the stator 8, a rotor, for example a hollow cylindrical one, is arranged concentrically to the axis (rotor axis) 5 in a manner not shown and is fixed to the rotor shaft 6 in a rotationally fixed or shaft-fixed manner. The rotor shaft 6 is rotatably mounted about the axis (rotor axis) 5 by means of a bearing (not shown) fixed in a housing base (page 8) and a bearing 9, preferably a ball bearing, held on the bearing shield 3. The rotor comprises, in a manner not shown, a laminated core to which permanent magnets are attached. During operation of the electric motor 1, these magnets interact with electromagnets of the stator 8, causing the rotor and the rotor shaft 6 to rotate about the axis 5.
[0035] The electric motor 1 can be connected to, for example, a pump block by means of a flange 10 provided on the motor housing 2 in the area of the bearing shield 3, preferably by means of screws. When the electric motor 1 is connected to the pump block, its electrically driven gear 4 meshes, in a manner not shown, with a gear of a transmission, which is coupled, for example, to a brake booster, in particular an electro-hydraulic one, as an auxiliary unit of a motor vehicle.
[0036] With particular reference to Figures 3 and 4, each connection contact 7 is designed as a busbar-like contact or as a flat contact with a first contact end 7a and a second contact end 7b. In the exemplary embodiment, two of the three connection contacts 7 are integrally formed on a busbar 7c extending in the circumferential direction U of the contact adapter 13. The connection contacts 7, or rather the respective busbar 7c, are encased in a plastic overmolding 7d, leaving the two contact ends 7a and 7b exposed.
[0037] The stator 8 has at least one (electrical) coil 12 on each of its star-shaped, radially inwardly arranged stator teeth 11, which are provided with electrical insulation. The coils 12 are connected by means of a contact adapter 13 to form a stator or rotating field winding 14, for example in a star or delta connection. During operation of the electric motor 1, which is designed as a brushless DC motor (BLDC), the coils 12, and thus the three-phase rotating field winding 13, are energized via the connection contacts 7 with alternating current that is 120° out of phase. This alternating current is generated by motor electronics (not shown), preferably with a bridge circuit. Page 9
[0038] Figure 2 shows the stator 8 and the contact adapter 13 arranged on its end face, as well as the axially oriented connection contacts 7. The contact adapter 13 has an annular plastic housing as a wiring housing.
[0039] 15 with a number of sockets 16. A plate-shaped contact or connection element 17 is inserted into each of these sockets. In the exemplary embodiment, each contact element 17 has two spaced-apart slot-like insulation displacement contacts 18, with which coil or winding sections 19, for example also coil ends, of the coils 12 are electrically connected to each other, forming a connection point of the stator or rotating field winding 14. On the longitudinal side opposite the spaced-apart insulation displacement contacts 18, each contact element 17 has an axially accessible contact slot 20. This means that the contact slot 20 is open on the side of the sockets 16 opposite the stator teeth 11 when the connection contact 7 is inserted parallel to the axial direction A.
[0040] As can be seen particularly in Figure 4, the respective connection contact 7 is seated with its first contact end 7a in the contact slot 20 of one of the contact elements 17 arranged side by side in the circumferential direction U of the contact adapter 13 and is clamped therein. In the exemplary embodiment, the connection end 7a of the middle connection contact 7 is designed as a blade contact extending directly in the longitudinal direction of the connection contact 7, and in the two outer connection contacts 7 as a blade or flat contact at the end of a circular arc-shaped section of the busbar 7c. In the exemplary embodiment, at least the middle of the three connection contacts 7 has a locking contour 21 at its first, blade-like contact end 7, which secures the connection contact 7 in the associated socket.
[0041] 16 anchored.
[0042] Figure 5 shows the respective pocket 16 with opposing sides
[0043] The slots 22 are aligned with the contact slot 20 of the contact element 17 located in the socket 16 on side 10. Figures 6 to 8 show the contact end 7a of the connecting contact 7 with the locking contour 21 molded onto it.
[0044] The locking contour 21 is formed in the form of opposing, backward-facing (barbed) hooks with respect to the insertion direction of the connecting contact 7, which is parallel to the axial direction A. The locking contour 21 ensures that axial forces are absorbed at the interface between the connecting contact 7 and the contact element 17 of the contact adapter 13, which is seated in the respective socket 16, and that the contact is sufficiently secured against movement or vibration. The locking contour 21 reliably prevents the connecting contact 7 from sliding out of the associated socket 16 of the contact adapter 13.
[0045] The socket 16 of the contact adapter 13, or its wiring housing 15, has intersecting or mutually cross-shaped socket sections 16a, 16b. A first socket section 16a extends circumferentially U, or tangentially, to the contact adapter 13. This first socket section 16a serves to receive the contact element 7.
[0046] The second pocket section 16b, which intersects the first pocket section 16a centrally, is oriented radially in the direction R. The connecting contact 7, which has a locking contour 21, is inserted into the contact slot 20 of the contact element 17 in the second pocket section 16b, in which the contact slot 20 of the contact element 17 inserted into the corresponding pocket 16 is located, forming a clamping contact. The locking contour 21 then engages in the pocket 16 in the area of the second pocket section 16b.
[0047] As illustrated in Figures 7 and 8 and as can be seen in conjunction with Figures 5 and 6, the plug pocket 16 is closed in the area of the plug slots 22 of the second pocket section 16b, which receives the connecting contact 17 with the locking contour 21. For this purpose, the plug pocket 16 has a side 11 on each of its opposite outer sides in the area of the plug slots 22.
[0048] Wall section 23, which extends axially in the insertion direction of the connection contact 7. The hook-shaped locking contour 21 engages in this wall section 23.
[0049] In summary, the invention relates to a stator 8 with a number of coil-carrying stator teeth 11 and with a contact adapter 13 with plug-in pockets 16, into which contact elements 17 with an insulation displacement contact 18 for electrical contacting of coil sections 19 are inserted, and with a number of connection contacts 7, wherein the respective contact element 17 has a contact slot 20 into which the associated connection contact 7 is inserted or can be inserted, and wherein the connection contact 7 has a locking contour 21 that anchors the connection contact 7 in the plug-in pocket 16.
[0050] The invention is not limited to the embodiment described above. Rather, other variants of the invention can also be derived by a person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the embodiment can also be combined with one another in other ways without departing from the subject matter of the invention.
[0051] Page 12
[0052] Reference symbol list
[0053] 1 electric motor
[0054] 2 Motor housings
[0055] 3 Storage sign
[0056] 3a Through opening
[0057] 4 gear
[0058] 5 axle / motor / rotor axle
[0059] 6 Motor / rotor shaft
[0060] 7 Connection contact
[0061] 7a first contact end
[0062] 7b second contact end
[0063] 7c busbar
[0064] 7d plastic overmolding
[0065] 8 Stator
[0066] 9 warehouses
[0067] 10 Flange
[0068] 11 Stator tooth
[0069] 12 coils
[0070] 13 contact adapters
[0071] 14 Stator / rotating field winding
[0072] 15 wiring / plastic housings
[0073] 16 slip pockets
[0074] 16a Pocket section
[0075] 16b Pocket section
[0076] 17 Connection / Contact Element
[0077] 18 Insulation clamp contacts
[0078] 19 Coil / winding section
[0079] 20 contact slots
[0080] 21 Locking contour / (bar)hook
[0081] 22 slots
[0082] 23 Wall section Page 13
[0083] A Axial direction
[0084] R Radial direction
[0085] U circumferential direction
Claims
Page 14 Claims 1. Stator (8) of an electric motor (1 ), comprising - a number of stator teeth (11) oriented radially concentrically to a central axis (5), which carry coils (12) of a multiphase stator winding (14), - a contact adapter (13) with a number of sockets (16) into which contact elements (17) with at least one insulation displacement contact (18) for electrical contacting coil sections (19) of interconnected coils (12) are inserted or can be inserted, and with a number of connection contacts (7) corresponding to the number of phases of the stator winding (14), - wherein the respective contact element (17) has an axially accessible contact slot (20) into which the associated connecting contact (7) is inserted or can be inserted in a clamping manner, and - wherein the connecting contact (7) has a locking contour (21) which anchors the connecting contact (7) in the associated plug pocket (16).
2. Stator (8) according to claim 1 , characterized in that the locking contour (21) is designed as at least one hook directed backwards with respect to the insertion direction of the connecting contact (7).
3. Stator (8) according to claim 1 or 2, characterized in that the contact adapter (13) has an annular interconnection housing (15) on which the plug pockets (16) are formed axially raised.
4. Stator (8) according to one of claims 1 to 3, characterized in that the respective plug pocket (16) has at least one plug slot (22), preferably plug slots (22) opposite each other, page 15 which aligns with the contact slot (20) of the contact element (17) located in the socket (16).
5. Stator (8) according to one of claims 1 to 4, characterized in that at least one of the socket pockets (16) of the contact adapter (13) has a first pocket section (16a) oriented in its circumferential direction (U) or tangentially to it for receiving the contact element (17) and a second pocket section (16b) extending transversely to the first pocket section (16a) or radially oriented in which the contact slot (20) of the contact element (17) for the connecting contact (7) having the locking contour (21) is arranged.
6. Stator (8) according to one of claims 1 to 5, characterized in that, - that at least one of the plug pockets (16) of the contact adapter (13) is closed on the outer side facing away from the contact slot (20) of the contact element (7) inserted in this plug pocket (16) along the plug-in direction of the connecting contact (7) having the locking contour (21), and / or - that at least one of the plug pockets (16) of the contact adapter (17) has a wall section (23) extending in the plugging direction of the connection contact (7) into which the locking contour (21) of the connection contact (7) snaps into place or, in particular, cuts into it by deforming.
7. Stator (8) according to one of claims 1 to 6, characterized in that the blocking contour (21) is formed at a contact end (7a), in particular knife-like, of the connecting contact (7), in particular at a narrow side or at opposite narrow sides of the connecting contact (7) or of the contact end (7a). Page 16 8. Stator (8) according to one of claims 1 to 7, characterized in that the contact slot (20) of the respective contact element (7) is arranged on the axially opposite side of the insulation displacement contact (18), in particular between two insulation displacement contacts (18) spaced apart from each other.
9. Stator (8) according to one of claims 1 to 8, characterized in that, - that the or each connecting contact (7) is connected to a circumferential (U) of the contact adapter (13) running busbar (7c) is formed, and / or - that the connecting contact (7) or the respective busbar (7c) is embedded in or encased by electrical insulation (7d), in particular in a plastic overmolding.
10. Electric motor (1) with a stator (8) according to one of claims 1 to 9.