ELECTRIC MOTOR AND SWITCHING UNIT FOR THIS

Description

[0001] The invention relates to an electric motor, in particular a radiator fan motor of a motor vehicle, with a switching unit for the coil ends of a motor or stator winding of the electric motor, according to the preamble of claim 1. It further relates to such a switching unit. Such an electric motor and such a switching unit are known, for example, from DE 101 52 006 A1.

[0002] A brushless electric motor has a stator with a number of stator teeth, arranged, for example, in a star shape, which support an electrical stator winding (motor winding) in the form of individual stator coils, which in turn are wound from an insulated wire. The coils are assigned to individual strands by their coil ends and are interconnected in a predetermined manner via connecting conductors of a switching unit.

[0003] In the case of a brushless electric motor as a three-phase AC machine, the stator has three strands and thus at least three connecting conductors, each of which is supplied with an electric current in a phase-shifted manner to generate a rotating magnetic field in which a rotor, usually equipped with permanent magnets, rotates. The connecting conductors are routed to the motor electronics to control the electric motor. The coils of the stator winding are interconnected in a specific manner using the connecting conductors. The type of interconnection is determined by the winding pattern of the stator winding, with a star connection or a delta connection of the coils being common.

[0004] Stator winding with a number of windings per phase, which are connected either in parallel or in series. The connector assembly comprises an annular wire guide element for receiving the ends of the windings and a connection receptacle in the form of three annular connecting bars, each with a cable lug at the end. Furthermore, the connecting bars have axially extended wire terminals to ensure electrical contact for the three phases through the slots of the wire guide element.

[0005] US 2005 / 0088049 A1 discloses a stator for an electric motor with an annular stator core with multiple stator teeth. An annular connecting unit is attached to one end or face of the stator. The annular connecting unit comprises deflection elements and a support element equipped with a receptacle and slots. Located in the receptacle are a series of mutually insulated connecting rings, each of which has contact elements that extend outward through the slots.

[0006] DE 10 2009 036 128 A1 discloses an electric motor comprising a stator with twelve stator windings, some of which are connected in series and ultimately to form a star connection. For the connection, a support element and a conductor structure consisting of four wires are provided, which are accommodated by the support element by clipping the wires into this support element. The wires form a complete ring or partial ring sections, with such a wire forming the star connection as a complete ring in conjunction with the coil ends of the stator windings. The support element has axial guides for the coil ends, with the electrical connection between the coil ends and the respective wires being established by soldering, welding, or hot-staking.

[0007] Circuit units with round wire contact wires for connecting and contacting the coil ends are known from US Pat. No. 7,948,130 B2 and DE 102 61 611 A1. With round wire contact wires, contacting the coil ends using conventional resistance welding is problematic because, due to the round wire cross-sections of both the coil ends and the respective contact wire, the involved wires tend to tilt when welded using smooth or flat electrodes. Such tilting of the wires leads to an undesirably high reject rate due to frequent weld failures.

[0008] The invention is therefore based on the object of providing an electric motor with a switching unit particularly suitable for simple and reliable connection and contacting of the winding coils. Furthermore, a switching unit with a number of contact wires, preferably arranged in a ring to form a connection ring, for connecting the coils is to be provided, the wire ends of which can be or are connected to one another and / or to phase terminals of the motor winding in a particularly suitable manner in an electrically conductive manner.

[0009] With regard to the electric motor, this object is achieved according to the invention with the features of claim 1 and with regard to the switching unit with the features of claim 9. Advantageous embodiments and further developments are the subject of the dependent claims.

[0010] For this purpose, the electric motor has a switching unit with a number of contact wires and with an annular frame part with a number of slotted plug-in pockets. The contact wires are arranged to form an interconnection ring for the coil ends of a stator winding. The wire ends of the contact wires (copper wires), which are preferably provided with an insulating sheath (insulation), are connected to insulation displacement contacts, i.e., they are electrically connected to one another. The or each insulation displacement contact has two insulation displacement legs spaced apart from one another to form an insulation displacement slot with a slot opening at the free end, for connecting at least two of the wire ends. The insulation displacement contacts, when assembled, are seated in plug-in pockets in the frame part of the switching unit.For this purpose, the respective plug-in pocket of the frame part suitably has one with at least two of the wire ends, wherein the insulation displacement contacts sit in the plug-in pockets of the frame part of the switching unit when assembled. For this purpose, the respective plug-in pocket of the frame part suitably has a slot aligned with the insulation displacement slot of the insulation displacement contact inserted into this plug-in pocket. These slots of the insulation displacement contact and the plug-in pockets on the frame part expediently run axially, i.e. in the axial direction with respect to the assembled state of the electric motor. An insulation displacement contact is usually a connecting element for connecting a plug element to a wire, for example also an insulated wire. Such an insulation displacement contact is usually provided and designed for the insulation displacement contacting of a single wire.

[0011] In contrast, the insulation displacement contact according to the invention is designed to connect two or more wires (copper wires) to form a permanent connection. The insulation displacement slot and / or the insulation displacement legs of the insulation displacement contact are therefore designed such that the at least two wire ends inserted one behind the other in the longitudinal direction of the slot and guided there along at least one knife edge on the leg side are securely clamped.

[0012] Experience has shown that the insulation displacement slot of the or each insulation displacement contact has, in the longitudinal direction of the slot, a first slot region adjoining a slot opening on the leg-free end and an adjoining, diamond- or rhombus-shaped, widened second slot region. Suitably, the or each leg of the respective insulation displacement contact has at least one raised joining contour on the outside of the leg.

[0013] A suitable embodiment additionally or alternatively provides that the insulation displacement slot of the or each insulation displacement contact has, in a slot end region facing away from a leg-free end slot opening in the slot longitudinal direction, a preferably circular recess contour which forms a predetermined bending point (predetermined bending point) for the insulation displacement legs.

[0014] According to a practical refinement of this predetermined bending point of the insulation displacement leg, the recess contour forms a contact contour that narrows the insulation displacement slot, against which the first wire end inserted into the insulation displacement slot abuts. This wire end then essentially forms the stop for the second wire end inserted into the insulation displacement slot.

[0015] With regard to the switching unit for such a preferably brushless electric motor, with a number of contact wires for connecting coils of a stator or motor winding, the insulation displacement contacts suitably form a corresponding number of phase connections, for example, three phase connections in a three-phase electric motor or a three-phase motor winding. The connections of the wire ends of the contact wires, preferably arranged in a connection ring, established by means of the insulation displacement contacts can also be used for the phase connections of a multi-phase motor or stator winding.

[0016] The insulation displacement contact has two legs (insulation displacement legs). Between the legs, a slot (insulation displacement slot) is formed, which is open at the leg-free ends and closed at the opposite leg ends. The opposing leg edges are designed such that a wire (conductor) inserted into the slot from the slot opening is cut and / or incised at the leg edges (hereinafter referred to as knife edges) (on the circumference), thereby severing the wire insulation. The flexible legs exert a spring-like clamping force on the respective wire (the respective wire end). In the insulation displacement state of the wire or wire end, the knife edges of the insulation displacement legs run virtually tangentially to the usually approximately circular wire diameter.

[0017] The cutting edge or knife edge and / or slot geometry of the insulation displacement contact is such that in the longitudinal direction of the slot both a first and at least one second wire (wire end) are reliably clamped into the insulation displacement slot of the same insulation displacement contact.

[0018] In particular, a specific, predetermined and / or selected ratio of the cutting depth of the wire (wire end) to the wire diameter is created by means of the knife edge arrangement and / or contour. The geometry or knife edge contour and / or slot geometry is such that a first wire (wire end) is pressed into the insulation displacement contact during contact and is cut at the knife edge or the two knife edges flanking the slot. The wire is oriented normal to the slot plane of the insulation displacement contact. In the area of ​​the insulation displacement edges, the wire diameter is reduced by, for example, 20% to 25%, while the wire subsequently cut during contact is cut by a smaller amount, for example, 10% to <20%, in the area of ​​the cutting edges.The or each wire is oriented normal to the slot plane of the insulation displacement contact.

[0019] In a particularly advantageous embodiment, the slot geometry is such that, starting from the slot opening, there is initially a first, preferably comparatively short, cutting area, followed by an expanded second area and, in turn, a third, preferably comparatively long, cutting area. The expanded area is, for example, diamond-shaped, in that an approximately V-shaped notch is made in each of the two opposite legs. Since the insulation displacement contact is preferably a stamped part, both this geometry and another geometry or contour representing the expanded area are conceivable. In the expanded area, the mutually facing edges of the legs do not necessarily have to be designed as knife edges.

[0020] Preferably, opposite this widened area, locally raised contours are suitably formed on the outside of the insulation displacement legs. Furthermore, additional joining contours (pins and / or grooves) are expediently formed or stamped along the outside of the insulation displacement legs.

[0021] The widened area of ​​the slot has the advantageous purpose and suitable function of accommodating the initially (first) wire cut in the slot as soon as the further (second) wire reaches the comparatively short or narrow cutting area adjacent to the insertion opening of the slot between the knife edges of the oppositely arranged legs. Since in this position the first wire is located in the widened area of ​​the slot, the required insulation displacement forces of the two legs act on the second wire in the cutting area upstream of the slot opening. In this way, both wires are cut one after the other and can then be guided or pressed further in the longitudinal direction of the slot via the widened area into the adjoining insulation displacement area, which functions in particular as a clamping area, with clamping contact.

[0022] According to a further advantageous embodiment, the insulation displacement contact interacts with a receiving pocket adapted to its outer contour, particularly in the region of its legs. This is suitably also slotted, with opposing pocket-side slots being aligned with the slot of the insulation displacement contact when assembled. The joining contours formed on the outside of the insulation displacement contact enable a firm, force-fitting and / or positive fit of the insulation displacement contact within the joining or receiving pocket, so that a reliable and / or additional force is exerted on the or each contacted wire, preferably via the legs. The wires to be contacted can already be inserted into the slot areas of this insertion or receiving pocket when the insulation displacement contact is pressed into this joining pocket of the additional part.Alternatively, the contact that is already insulation displacement contacted with the two wires can then be inserted into the pocket.

[0023] Advantageously, the or each joining pocket is a component of the (annular) frame part of the switching unit for the circuit-technically predetermined contacting of the contact wires, coil end and / or phase connections for the stator or motor winding of the electric motor, in particular a radiator fan motor of a motor vehicle.

[0024] For contacting phase-side connections, three such insulation displacement contacts with associated joining or plug-in pockets are provided in the frame part of the switching unit (connection or termination ring), for example, and are arranged equidistant from one another. The preferably circular frame part also accommodates contact wires intended for connecting the coils of the stator winding, which are contacted with the respective coil ends and / or phase connections.

[0025] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings: Fig. 1a and 1b shows an insulation displacement contact with an insulation displacement slot flanked by two insulation displacement legs without or with a joining contour arranged on the outside of a slot opening, Fig. 2 shows one of the insulation displacement legs of an insulation displacement contact with a circular recess in the leg transition area producing a desired bending point, Fig. 3 shows a perspective view of an interconnection ring with several contact wires arranged in a circle and three equidistantly arranged insulation displacement contacts, Fig. 4 shows a view according to Figure 3 a switching unit with such a connection ring and with an annular frame part, Fig. 5 the switching unit according to Figure 4 without interconnection ring and with a view of a plug-in pocket without inserted insulation displacement contact, Fig. 6 in a representation according to Fig. 5an embodiment of the switching unit with closed coil cassettes Fig. 7 in perspective view of a stator with attached switching unit, Fig. 8 in perspective view of the stator with attached switching unit and the rotor as well as the electronics (circuit board) of an electric motor connected to the insulation displacement contacts, and Fig. 9 in perspective view of the electric motor as a radiator fan motor for a motor vehicle including switching unit and electronics.

[0026] The Figures 1a and 1bshow an insulation displacement contact 1, hereinafter also referred to simply as a contact, with an insulation displacement slot, hereinafter simply referred to as a slot 2, which is flanked by two limbs 3 of the insulation displacement limb of the insulation displacement contact 1, i.e., is located or formed between these two limbs 3. The contact 1 is preferably a stamped part. The limbs 3 of the contact 1 merge into a contact head 5, preferably provided with a through-opening (through-bore) 4. Joining contours 6 (grooves, pins) are formed or stamped onto the outside of the limbs 3.

[0027] The slot 2 has a slot opening 7 in the region of the free ends of the legs 3. Adjoining this opening in the longitudinal direction 8 of the slot is a first, comparatively short insulation displacement contour 9. This transitions into an expanded region 10 in the longitudinal direction 8 of the slot. This expanded region 10 is preferably diamond-shaped. This region 10, in turn, is adjoined by another, comparatively long insulation displacement region, or at least a clamping region 11. This clamping region ends at the ends opposite the free ends, i.e., at the transition region 12 of the legs 3.

[0028] Due to these contact geometries, reliable contact or connection is possible not just for one wire, but for two or more wires. These wires are inserted or pressed into the slot 2 one after the other in the longitudinal direction 8 of the slot and are cut circumferentially (azimuthally). The cutting depth is greater than or equal to the thickness of the insulation (insulating sheath) of the or each wire. For this purpose, the mutually facing leg edges of the legs 3 in the region of the slot 2 are designed as knife-like knife edges 13. The diameter reduction of the first wire cut in the slot 2 is, for example, approximately 22%, while the diameter reduction of the further wire cut in the slot 2 is, for example, approximately 16%, based on a copper wire with a diameter of, for example, 1.12 mm and wire insulation of, for example, 0.003 mm, i.e. a total wire diameter of approx.1.15 mm to 1.16 mm.

[0029] At the Fig. 2 In the illustrated embodiment of the insulation displacement contact 1, of which only the left insulation displacement leg 3 is shown, the diamond-shaped region 10 has a tapered, comparatively pronounced cutting contour 10a on the side facing the slot opening 7. In or at the transition region 12 of the legs 3, a circular recess contour 12a is provided in the exemplary embodiment. This leads to an at least slight reduction in the leg width b of the legs 3 compared to the leg width of the insulation displacement contacts 1 according to the Figures 1a and 1b without such a recess contour in the transition area 12.

[0030] This recess contour 12a defines a desired bending point 12b for the legs 3 when they bend outward upon insertion of the wires or wire ends designated 20 into the insulation displacement slot 2 of the contact 1. The recess contour 12a also forms a contact edge 12c that narrows the insulation displacement slot 2, for example, in the form of a sector-shaped projection, as an internal stop for the wire ends 20.

[0031] Figure 3 shows an interconnection ring 18 with several contact wires 19 arranged in a circle and three equidistantly arranged insulation displacement contacts 1, each of which makes insulation displacement contact with two wires or wire ends 20.

[0032] Figure 4shows a switching unit 21 with such a connection ring 18. The switching unit 21 has an annular frame body (frame part) 22, preferably made of plastic. This, in turn, has a receiving pocket (insertion / joining pocket) 23 in the area of ​​the respective insulation displacement contact 1 for receiving the insulation displacement contact 1.

[0033] Figure 5shows the switching unit 21 or the frame part 22 according to Figure 4 with two insulation displacement contacts 1 inserted into the associated insertion pockets 23, while the insertion pocket 23 visible in the foreground of the figure can be seen without an insulation displacement contact 1. The slots 25 introduced into these insertion pockets 23, each of which has a slotted opening 24 at its end, are aligned with the slot 2 of the respective insulation displacement contact 1. The respective frame-side slotted opening 24 is located on the slot side opposite the slotted opening 7 of the insulation displacement contact 1, i.e., on the insertion or insertion side of the respective insertion pocket 23.

[0034] As in the Figures 3 and 4 As can be seen, the contacted wire ends 20 run normal to the slot plane spanned by the slot 2.

[0035] Figure 6shows a further embodiment of the switching unit with complete, closed coil cassettes 26, which are formed on the frame part 22 of the switching unit 21. These take up in the assembled state of the Figure 7 shown stator 27 of an electric motor 28 each have its stator teeth and are or will be wound in a manner not shown in detail with the individual coils of the stator winding.

[0036] Figure 8 shows the stator 27 provided with the switching unit 21 according to Figure 7including rotor 29 and motor axis 30 as well as including electronics (printed circuit board) 31 and their contacting with the insulation displacement contacts 1 via their contact heads 5. These are inserted into, for example, crimp-tab-like plug-in pockets 32 of contacts (flat contacts) or contact sections 33 manufactured, for example, as stamped and bent parts from flat wire and form the phase connections for the three-phase current supply to the stator or motor winding.

[0037] Figure 9 shows the assembled or assembled electric motor 28 as a radiator fan motor for a motor vehicle including stator 27, switching unit 21 and fan wheel 34. List of reference symbols

[0038] 1Insulation displacement contact 2Insulation displacement slot 3Insulation displacement leg 4Through opening / bore 5Contact head 6Joining contour 7Slot opening 8Longitudinal slot direction 9Insulation displacement contour 10Area 11Insulation displacement area 12Transition area 12aRecess contour 12bPredetermined bending point 12cContact edge / stop 13Knife edge 18Connection ring 19Contact wire 20Wire / wire end 21Switching unit 22Frame part / body 23Receiving / inserting / joining pocket 24Slot opening 25Slot 26Coil cassette 27Stator 28Electric motor 29Rotor 30Motor shaft 31Electronics / circuit board 32Inserting pocket 33Contact / section 34Fan wheel

Claims

1. Electric motor (28), comprising a switching unit (21) having a number of phase connections and with a number of contact wires (19) and with an annular frame part (22), - wherein the contact wires (19) are arranged to form an interconnection ring (18) for the coil ends of a stator winding, and - wherein the frame part (22) of the switching unit (21) has a number of insertion pockets (23), which corresponds to the number of insulation-displacement contacts (1), for receiving the insulation-displacement contacts (1), each of which has two insulation-displacement limbs (3), which are spaced apart from one another so as to form an insulation-displacement slot (2), characterized - in that the phase connections are formed by a corresponding number of insulation-displacement contacts (1) or comprise said insulation-displacement contacts, - in that at least two wire ends (20) of the contact wires (19) are connected to the insulation-displacement contacts (1), - in that the insulation-displacement slot (2) of the or each insulation-displacement contact (1) has, in the slot longitudinal direction (8), a first, comparatively short insulation-displacement contour (9) which adjoins a limb free end-side slot opening (7) and merges with a slot region (10) which is widened in a diamond-shaped manner in the slot longitudinal direction (8) and is adjoined by a further, comparatively long clamping region (11), wherein the widened slot region (10) has a tapering, comparatively pronounced cutting contour (10a) on the side facing the slot opening (7), and - in that the widened slot region (10) is provided and designed to receive the first wire end (20) initially cut in the insulation-displacement slot (2) as soon as the second wire end (20) enters the first slot region, which adjoins the slot opening (7), between the blade edges of the insulation-displacement contour (9) of the insulation-displacement limbs (3) which are arranged opposite one another.

2. Electric motor (28) according to Claim 1, characterized in that the respective insertion pocket (23) of the frame part (22) has a slot (25) which is in alignment with the insulation-displacement slot (2) of the insulation-displacement contact (1) which is inserted into said insertion pocket (23).

3. Electric motor (28) according to Claim 1 or 2, characterized in that the insulation-displacement slot (2) and / or the insulation-displacement limbs (3) of the or each insulation-displacement contact (1) are / is designed in such a way that the at least two wire ends (20), which are introduced into the insulation-displacement slot (2) one behind the other in the slot longitudinal direction (8) and which are guided along at least one limb-side blade edge (13) there, are in reliable clamping contact.

4. Electric motor (28) according to one of Claims 1 to 3, characterized in that second slot region (10) of the insulation-displacement slot (2) of the or each insulation-displacement contact (1) is in the shape of a diamond or rhombus.

5. Electric motor (28) according to one of Claims 1 to 4, characterized in that the insulation-displacement slot (2) of the or each insulation-displacement contact (1) has a recess contour (12a), which forms a predetermined bending point for the insulation-displacement limb (3), in a slot end region (11) which is averted from a limb free end-side slot opening (7) in the slot longitudinal direction (8).

6. Electric motor (28) according to Claim 5, characterized in that the recess contour (12a), which serves as a predetermined bending point, is circular.

7. Electric motor (28) according to either of Claims 5 and 6, characterized in that the recess contour (12a), which serves as a predetermined bending point, forms an abutment contour (12c), which narrows the insulation-displacement slot (2), as a stop for the or each wire end (20).

8. Electric motor (28) according to one of Claims 1 to 7, characterized in that the or each limb (3) of the respective insulation-displacement contact (1) has, on the outside of the limb, at least one raised joining contour (6).