Electric motor of an auxiliary unit of a motor vehicle

Abstract

The invention relates to an electric motor (1) of an auxiliary unit of a motor vehicle, with a stator (8) having a number of electrical coils (15) which are connected by means of a contact adapter (16) to form a stator or rotating field winding (17), wherein the contact adapter (16) has a number of connection contacts (7) with a contact end (7b) for contacting a plug contact (25), and wherein the respective connection contact (7) has at least one guide geometry (23), in particular for collision-free guidance of the contact end (7b) of the connection contact (7) in a bore (24) of a pump block (22) of a brake booster.

Description

[0001] The invention relates to an electric motor of an auxiliary unit of a motor vehicle. The invention further relates to an auxiliary unit comprising such an electric motor.

[0002] Motor vehicles, especially passenger cars, typically contain a variety of auxiliary components that do not directly contribute to the vehicle's propulsion. These auxiliary components are necessary, for example, for the operation of the main drive system or serve to provide or enhance comfort for the vehicle's occupant. One such auxiliary component is an electric actuator, such as an electric window regulator. Another example is an electric refrigerant compressor, which is a component of the vehicle's refrigerant circuit.

[0003] Alternatively, the electric motor can be a component of the vehicle's braking system. In this case, the electric motor might be part of an anti-lock braking system (ABS), traction control (TCS), or electronically actuated brake force distribution (EBD). The electric motor can also be used in a brake booster, where it amplifies the applied pedal force. For example, the brake booster might be at least partially hydraulic, with the electric motor operating a hydraulic pump and / or actuating a number of valves.

[0004] Alternatively, the brake booster can be electromechanical. This electromechanical brake booster typically includes an input rod that is moved longitudinally by a foot or brake pedal to actuate the vehicle's brakes. The input rod acts on a working piston, which increases the pressure in the brake fluid system. The electric motor drives the input rod, thus assisting the foot pedal. This reduces the force required by the user to apply the brakes. Furthermore, the electric motor allows the brake booster to function independently of actual pedal actuation. Depending on the driving situation, the electric motor can move the input rod independently of the foot or brake pedal, resulting in deceleration of the vehicle.

[0005] The electric motor is typically designed as a brushless direct current (BLDC) motor. This type of electric motor has a rotor with several permanent magnets that is fixed to a rotor shaft. The rotor shaft is rotatably mounted around a rotor axis by means of one or more bearings, with each bearing potentially being mounted in a bearing housing of a bearing shield and / or the base of a (cup-shaped) motor housing.

[0006] The stator has several electrical coils which are electrically connected to form a multi-phase, in particular three-phase, rotating field or stator winding by means of a connecting ring or contact adapter mounted on the stator. Typically, each phase of the rotating field or stator winding, which is electrically offset by 120°, is electrically contacted by a (phase) terminal that passes through a corresponding opening in the end shield. On the side of the end shield opposite the stator, (motor) electronics for supplying current to the phases are usually arranged. The electronics comprise a bridge circuit provided by a printed circuit board, with each of the (phase) terminals being connected to the electronics.

[0007] For example, if, in a brake booster, especially an electro-hydraulic one, the connection contacts of the electric motor, which are intended as (phase) connections, are guided through a connection component, especially a pump block of a brake booster, with a number of through channels or through holes corresponding to the number of connection contacts, there is a risk of the connection contacts colliding with the channels or holes or with their inner wall during assembly.

[0008] There is also a risk that the respective connection contact on the component or pump block side facing away from the stator or a contact adapter of the electric motor will not be properly connected to a (connection) plug. To ensure collision-free contact between the connection contacts and the (customer-supplied) connector during automated blind assembly, precise positioning of the connection contacts (customer contacts) is necessary. However, the required positioning accuracy for proper plug contact is often problematic in terms of manufacturability due to the (axial) length of the connection contacts, which can lead to an undesirably high reject rate.

[0009] The invention is based on the objective of specifying a particularly suitable electric motor of an auxiliary unit of a motor vehicle as well as a particularly suitable auxiliary unit of a motor vehicle, wherein it is advantageously intended to enable the most reliable possible guidance of the connection contacts during assembly, in particular also during blind assembly, with a connection component.

[0010] With regard to the electric motor, this problem is solved according to the invention by the features of claim 1, and with regard to the auxiliary unit by the features of claim 10. Advantageous further developments and embodiments are the subject of the dependent claims.

[0011] The electric motor is advantageously a component of an auxiliary unit of a motor vehicle, preferably a brake booster, particularly an electro-hydraulic one. The electric motor has a stator arranged concentrically to a rotor axis, with a number of electrical coils connected by means of a contact adapter (connection ring) to form a multi-phase stator or rotating field winding. The contact adapter has a number of connection contacts arranged parallel to the rotor axis, corresponding to the number of phases, with first and second contact ends. The first contact ends are connected to the stator or rotating field winding, particularly via the contact adapter. The second contact ends are provided for connection to a plug or plug contact, particularly a customer plug.

[0012] Each connection contact has a guide geometry between the second contact end and the first contact end. This guide geometry is designed and configured to ensure collision-free guidance of the second contact end of the connection contact within a through-channel or through-bore of a connection component, particularly a pump block.

[0013] The respective connection contact is preferably encased between the first and second contact ends with a plastic overmolding, which forms or comprises the guide geometry. The guide geometry is provided, in particular, in a connection or axial section adjoining the second contact end (axially) and preferably comprising a plastic overmolding. The guide geometry is suitably radially flared with respect to the longitudinal axis of the connection contact, which is particularly busbar-like and parallel to the rotor axis.

[0014] In a preferred embodiment, the guide geometry is designed as a centering rib, preferably radially projecting or radially raised, extending axially, or as a pair of ribs, preferably on or within a plastic overmolding of the respective connection contact. Suitablely, the respective connection contact is a flat contact overmolded as a contact element – ​​leaving the second contact end free – with opposing narrow sides, each of which has a guide or centering rib as the guide geometry. Additionally or alternatively, the respective connection contact has a cross-sectional shape similar to an I-profile or double-T profile in a connection section of the plastic overmolding that axially adjoins the second contact end, the flanges of which form a pair of ribs as the guide geometry.

[0015] Preferably, the guide geometry connects directly to the second contact end of the respective connection contact and extends over 20% to 50%, preferably over (20 ± 5)%, of the length of the connection section of the contact element between the first contact end and the second contact end.

[0016] The electric motor suitably has a bearing shield between the stator and the end shield, wherein the connection contacts protrude through a through-hole in the bearing shield at their second contact end. The bearing shield suitably has a bearing receptacle for one or with a bearing. The bearing is expediently a rolling or ball bearing in which a motor or rotor shaft forming or defining the rotor axis is supported. A second bearing, in particular a rolling or ball bearing, for the motor or rotor shaft is preferably provided in a bearing receptacle in the base of a pot-shaped motor housing.

[0017] In an advantageous embodiment, the contact adapter, which expediently has a plastic housing, has a number of sockets, particularly on the housing side. Contact elements with a clamping contact are inserted into these sockets, by means of which one of the connection contacts is clamped. Suitablely, each contact element has at least one insulation displacement contact as a connection point for a wire section of the electrically interconnected coils of the stator or rotating field winding.

[0018] The auxiliary unit comprises a connecting component, in particular a pump block, with a number of through-holes, as well as the electric motor, whose connecting contacts, preferably without collision, are guided through the through-holes to connect to a plug connector. The auxiliary unit is advantageously a brake force booster, particularly vacuum-independent, and especially preferably electro-hydraulic, and expediently includes vehicle dynamics control (ESP functionality).

[0019] The advantages achieved with the invention consist in particular of the fact that, by means of the guide geometry provided on the connection contacts, which serves as a guide and / or for centering within bores or channels of a connection component, especially a pump block or flange, collision-free mounting of the connection contacts to the, in particular external or customer-supplied, connector is always possible. This guide geometry, preferably rib-like or rib-shaped, is designed such that contact of an upper (second) contact end of a free (copper) conductor track or a busbar as a contact element with the bores or through-channels in the connection component (pump block or flange) or contact with other components is avoided or practically eliminated, and reliable contact with the connector is ensured.

[0020] The guide geometry, particularly the continuous ribbed contour on each contact, guides the contact adapter within the connection component, pump block, or flange. This prevents or eliminates the risk of collision between the free, second contact end and a (customer-supplied) connector by preventing unwanted deflection of the contacts. Furthermore, the required positioning accuracy of the connector contacts can be increased, thus advantageously avoiding or at least significantly reducing rejects.

[0021] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing shows: Fig. 1 in a perspective view an electric motor of an auxiliary unit of a motor vehicle, with a pot-shaped motor housing and with a bearing shield as well as with connection contacts oriented parallel to a rotor axis, Fig. 2 in a perspective view a connection adapter with three clamp-type connection contacts, Fig. 3 in a side view a pump block of a brake booster as an auxiliary unit, through which the connection contacts of the electric motor penetrate, Fig. 4 in a top view the connection clone contacts guided in bores of the pump block with a view to each (bare, second) contact end as well as to a double-T profile of a guide geometry of a or on a plastic overmolding, Fig. 5 in a longitudinal section the electric motor with a view to the (bare, second) contact end of a connection block contact guided in the bore of the pump block with a plastic overmolding with the guide geometry, and Fig. 6 in a schematic sectional view one of the motor-side terminal contacts clamped to the connection adapter, the (upper, second) contact end of which is guided by means of the guide geometry without collision through the bore of the pump block into a plug contact of a connector.

[0022] Corresponding parts are marked with the same reference symbols in all figures.

[0023] In Fig. Figure 1 shows an electric motor 1 comprising a pot-shaped motor housing 2, which is closed with a bearing shield 3. A helical gear 4, in the 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 rotor axis 5. Furthermore, three connection contacts 7, oriented parallel to the rotor axis 5, are brought out of the bearing shield 3 through a through-opening 3a in the exemplary embodiment. The axial and radial directions with respect to the rotor axis 5 are indicated in Fig. 1 is labelled A or B.

[0024] With a view also to the Fig. The electric motor 1 comprises a hollow cylindrical stator 8 arranged in the motor housing 2. A hollow cylindrical rotor 9 is arranged concentrically to the rotor axis 5 within the stator 8 and is fixed to the rotor shaft 6 in a rotationally fixed manner. The rotor shaft 6 is rotatably supported about the rotor axis 5 by means of a first bearing 11 fixed in a housing base 10 and a second bearing 12 held on the bearing shield 3. The respective bearings 11 and 12 are preferably ball bearings.

[0025] The rotor 9 comprises, in an unspecified manner, a laminated core to which permanent magnets 13 are attached. These magnets interact with electromagnets of the stator 8 during operation, causing the rotor 9 and the rotor shaft 6 to rotate about the rotor axis 5. The stator 8 has at least one (electrical) coil 15 on each of its star-shaped, electrically insulated stator teeth 14. The coils 15 are connected by means of a contact adapter 16 to form a stator or rotating field winding 17, for example in a star or delta configuration. During operation of the electric motor 1, which is designed as a brushless DC motor (BLDC), the coils 15, and thus the three-phase rotating field winding 17, 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.

[0026] In Fig. Figure 2 shows the stator 8 and the contact adapter 16 arranged on its end face, as well as the axially oriented connection contacts 7. The contact adapter 16 has an annular plastic housing 18 with a number of plug-in pockets 19, each containing a plate-shaped contact element 20 with a Fig. 6 is inserted into the clamping contact designated 20a. The respective connection contact 7 is (clamp-)connected to this contact with a first contact end 7a. In the exemplary embodiment, the contact end 7a is designed as a flat contact extending directly in the longitudinal contact direction L of the connection contact 7 for the middle connection contact 7, and as a flat contact at the end of a circular arc-shaped busbar section for the two outer connection contacts 7.

[0027] The first contact ends 7a are connected to the terminal contacts 7 in each of the contact elements 20 arranged side by side in the circumferential direction of the contact adapter 16. In the exemplary embodiment, each contact element 20 also has two insulation displacement contacts 20b, with which wire or winding sections 15a, for example also coil ends, of the coils 15 are electrically connected to each other, forming a connection point of the stator or rotating field winding 17.

[0028] With a view also to the Fig. 5 and Fig. 6 the respective connecting contact 7 is a contact element 7c, preferably a flat contact, in particular a busbar-like contact element, with the first contact end 7a and with a second contact end 7b as well as with a plastic overmolding 7d which encloses the contact element 7c while leaving the two contact ends 7a, 7b free.

[0029] As especially in the Fig. As can be seen from Figures 3 to 6, the electric motor 1 is connected to a pump block 22 by means of a flange 21 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 22, its electrically driven gear 4 meshes, in a manner not shown in detail, 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.

[0030] The respective connection contact 7 has a guide geometry 23 between the second contact end 7a and the first contact end 7b. The guide geometry 23 is designed for collision-free guidance and / or centering of the second contact end 7b of the connection contact 7 in a through-hole 24 of a connection component 23, hereinafter referred to as a pump block 23. The respective connection contact 7 extends with its second (bare) contact end 7b through the respective bore 24 of the pump block 22, as shown in particular in Fig. 3 is evident.

[0031] The guide geometry 23 is part of the plastic overmolding 7d that surrounds the respective connection contact 7 between the first contact end 7a and the second contact end 7a. The guide geometry 23 is located in an axial section L adjoining the second contact end 7b axially or in the longitudinal contact direction L. bThe plastic overmolding 7d is provided. With respect to the longitudinal contact direction L or the longitudinal axis of the connecting contact 7 parallel to the rotor axis 5, the guide geometry 23 is raised in the radial direction R and thus radially projected. The guide geometry 23 connects directly to the second contact end 7b of the respective connecting contact 7. The guide geometry 23 preferably extends over (25 ± 5) % of the length L. a of the connecting or axial section L b between the first contact end 7a and the second contact end 7b. In other words, the axial length L is a the guide geometry 23 approximately 20% to 30% of the length L a of the connecting contact 7 or its plastic overmolding 7d.

[0032] The guide geometry 23 is designed as an axially extending, radially flared centering rib or as a pair of ribs on the plastic overmolding 7d of the respective connection contact 7. The electrically conductive contact element 7c within the plastic overmolding 7d of the connection contact 7 is a flat contact in the form of a busbar with opposing narrow sides, each of which has a centering rib as guide geometry 23.

[0033] As can be seen particularly from the Fig. 4 and Fig.As can be seen in Figure 5, the plastic overmolding 7d in the area of ​​the guide geometry 23 forms a double-T profile or I-profile in cross-section, the flanges of which form the guide geometry 23 as a pair of ribs. This rib-like guide geometry 23 reliably guides the respective connection contact 7 during the assembly of the electric motor 1 and the pump block 22, particularly during blind assembly, preventing collisions or contact of the second contact end 7b with the inner wall of the bore 24. This ensures the desired positioning accuracy of the connection contact 7, reliably guiding the second contact end 7b into a corresponding plug contact 25 of a connector 26, thus establishing a secure plug connection.

[0034] In summary, the invention relates to an electric motor 1 of an auxiliary unit of a motor vehicle, with a stator 8 having a number of electrical coils 15 which are connected by means of a contact adapter 16 to form a stator or rotating field winding 17, wherein the contact adapter 16 has a number of connection contacts 7 with a contact end 7b for contacting a plug contact 25, and wherein the respective connection contact 7 has at least one guide geometry 23, in particular for collision-free guidance of the contact end 7b of the connection contact 7 in a bore 24 of a pump block 22 of a brake booster.

[0035] 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. Reference symbol list 1 electric motor 2 Motor housings 3 Storage sign 3a Through opening 4 gear 5 Rotor axis 6 Rotor shaft 7 Connection contact 7a first contact end 7b second contact end 7c Contact element 7d plastic overmolding 8 Stator 9 Rotor 10 Case bottom 11,12 warehouses 13 Permanent magnet 14 Stator tooth 15 coils 15a Wire / winding section 16 contact adapters 17 Stator / rotating field winding 18 plastic housings 19 slip pockets 20 contact elements 20a Terminal contact 20b Insulation clamp contact 21 Flange 22 Pump block / connection component 23 Guide geometry / rib 24 Borehole / Through channel 25 plug contacts 26 connector plugs A Axial direction B Radial direction L Contact longitudinal direction L a Length of the connecting section L b Axial / connection section

Claims

[1] Electric motor (1) of an auxiliary unit, in particular a brake booster, of a motor vehicle, with a stator (8) arranged concentrically to a rotor axis (5), which has a number of electrical coils (15) which are connected by means of a contact adapter (16) to form a multi-phase stator or rotating field winding (17), - wherein the contact adapter (16) has a number of connection contacts (7) arranged parallel to the rotor axis (5), in particular busbar-like, corresponding to the number of phases, with a first contact end (7a) contacted with the stator or rotating field winding (17) and with a second contact end (7b) for contacting a plug contact (25), and - wherein the respective connecting contact (7) is located between the second contact end (7b) and the first contact end (7a), in particular in a connecting or axial section (L) which is axially adjoining the second contact end (7b) and preferably has a plastic overmolding (7d). a ) has at least one, in particular radially flared, guide geometry (23). [2] Electric motor (1) according to claim 1, characterized by , that the guide geometry (23) is provided and designed or configured for collision-free guidance of the second contact end (7b) of the connection contact (7) in a through channel or in a through bore (24) of a connection component (22), in particular a pump block of a brake booster. [3] Electric motor (1) according to claim 1 or 2, characterized by, that the respective connecting contact (7) between the first contact end (7a) and the second contact end (7b) is encased in a plastic overmolding (7d) which forms or has the guide geometry (23). [4] Electric motor (1) according to any one of claims 1 to 3, characterized by , that the guide geometry (23) is designed as a guide or centering rib, in particular extending axially, preferably radially flared or radially raised, or as a pair of ribs, preferably a plastic overmolding (7d) of the respective connection contact (7). [5] Electric motor (1) according to any one of claims 1 to 4, characterized by , - that the respective connecting contact (7) is a contact element (7c) overmolded, in particular designed as a flat contact, with opposing narrow sides on each of which a guide or centering rib is provided as a guide geometry (23), leaving the second contact end (7b) free, and / or - that the respective connection contact (7) is in a connection section (L) axially adjoining the second contact end (7b). b ) the or a plastic overmolding (7d) has a cross-sectional shape in the form of an I-profile or double-T-profile, the flanges of which form a pair of ribs as a guide geometry (23). [6] Electric motor (1) according to any one of claims 1 to 5, characterized by , - that the guide geometry (23) connects directly to the second contact end (7b) of the respective connecting contact (7), and / or - that the guide geometry (23) extends over 20% to 50%, preferably over (20 ± 5)% of the length (L a ) of the connection section between the first and second contact ends (7a, 7b). [7] Electric motor (1) according to any one of claims 1 to 6, characterized by , that the connecting contacts (7) with the second contact end (7b) protrude through a through-opening (3a) of a bearing shield (3), wherein the contact adapter (7) is arranged between the stator (8) and the bearing shield (3). [8] Electric motor (1) according to any one of claims 1 to 7, characterized by , that the contact adapter (16) has a number of plug pockets (19) each with a contact element (20) inserted therein, with a clamping contact (20a) by means of which one of the connection contacts (7) is contacted. [9] Electric motor (1) according to claim 8, characterized by, that each contact element (20) provides an insulation displacement contact (20b) as a connection point for a wire section of the electrically interconnected coils (15) of the stator or rotating field winding (17). [10] Auxiliary unit of a motor vehicle, in particular an electro-hydraulic brake booster, with a connecting component having a number of through holes (24), in particular a pump block (22), and with an electric motor (1) according to one of claims 1 to 9, the connecting contacts (7) of which are guided with their second contact ends (7b), preferably without collision, over the through holes (24) for contact with a connector plug (26).

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