Brushless electric motor, especially for a windshield wiper motor

Abstract

The invention relates to a brushless electric motor (10), in particular for a windshield wiper motor (100), with a stator (16) that is at least substantially ring-shaped, wherein the stator (16) interacts with a rotatably mounted rotor (38) arranged concentrically to the stator (16), wherein a shaft (40) of the rotor (38) is rotatably mounted by means of at least two bearing devices (42, 44), wherein the rotor (38) is mounted axially free of play in the direction of an axis of rotation (48) of the shaft (40) in a housing (46; 46a) of the electric motor (10) by means of an axial play compensation device (66; 66a; 66b), and wherein the stator (16) is positioned by contact with a component in a direction perpendicular to the axis of rotation (48) of the shaft (40) towards the housing (46; 46a).

Description

State of the art

[0001] The invention relates to a brushless electric motor, in particular for a windshield wiper motor, with the features of the preamble of claim 1.

[0002] Such an electric motor, known from EP 3 249 787 A1, is characterized in particular by the fact that its axial backlash compensation device forms a stop for the stator terminal. This enables the terminal to be supported when it contacts the current supply connection elements in a direction perpendicular to the axis of rotation of a rotor of the electric motor.

[0003] Furthermore, it is known from DE 33 38 507 A1 and US 2017 / 0207684 A1 to design the axial play compensation device with a system section that forms an axial stop for a bearing device of the runner shaft. Disclosure of the invention

[0004] The brushless electric motor according to the invention, in particular for a windshield wiper motor, with the features of claim 1, has the advantage that axial positioning of the stator of the electric motor in the housing of the electric motor is achieved in a structurally relatively simple manner by means of a special design of the extension of the connecting body and the axial play compensation device. For this purpose, it is provided according to the invention that the stator is fixed in the housing in a direction parallel to its longitudinal axis, and that the fixing by means of the axial play compensation device is effected by bearing against the extension of the stator.

[0005] Advantageous further developments of the brushless electric motor according to the invention, in particular for a windshield wiper motor, are listed in the dependent claims.

[0006] In a first variant of the axial play compensation device, it can be provided in particular that the axial play compensation device has a section running perpendicular to the axis of rotation of the shaft, which rests against the extension on the side facing away from the stator.

[0007] Alternatively, a second variant allows the extension to have a stop extending towards the shaft's axis of rotation, against which the axial play compensation device rests with a section running parallel to the shaft's axis of rotation. Considering that the extension or connecting body is designed as a plastic injection-molded part, this section can be manufactured or integrated into the extension very easily and cost-effectively.

[0008] In a manufacturing-technically preferred embodiment of the terminal body, it is made of plastic and produced by injection molding. The plastic construction, in conjunction with the geometric design of the terminal body's extension, results, according to the invention, in the extension's elasticity extending along the longitudinal axis of the stator. This elasticity is compensated for by the axial play compensation device without negatively impacting the electrical contact of the extension.

[0009] There are various design options for the axial play compensation device. One particularly advantageous embodiment, with regard to manufacturing costs, provides that the axial play compensation device is designed as an elastically deformable element, preferably made of sheet metal, which has a U-shaped opening for receiving the rotor shaft and can be mounted in a receptacle in the housing in a direction perpendicular to the axis of rotation of the shaft, so that a clamping connection is formed between the axial play compensation device and the shaft, whereby the axial play compensation device exerts an axial force on the shaft in the direction of a bearing assembly.

[0010] To ensure that the axial play compensation device is secured in the installed state contrary to the original mounting direction, a further development of the axial play compensation device just described provides that the contact point is formed on a side of the axial play compensation device facing away from the opening of the axial play compensation device.

[0011] With regard to the arrangement for receiving the axial play compensation device in the housing recess, it is also advantageous if the contact between the axial play compensation device and the extension of the connecting body is formed in an area spaced apart from the opening of the axial play compensation device in the direction of the axis of rotation of the shaft.

[0012] The contact with the system preferably takes place on a section of the axial play compensation device that runs parallel to the axis of rotation of the rotor shaft.

[0013] To ensure the proper functioning of the axial play compensation device, it must be positioned at a required target position relative to a direction perpendicular to the rotor's axis of rotation. This target position can be defined, for example, by a suitable design of the U-shaped receptacle, while ensuring that the base of the receptacle does not contact the rotor shaft. A further, structurally preferred embodiment for ensuring the final mounting position of the axial play compensation device therefore provides that the device has a contact section to form a stop against a mounting direction perpendicular to the rotor shaft's axis of rotation.

[0014] Preferably, the system section is arranged in operative connection with an outer circumference of a bearing assembly. Since the outer circumference of the bearing assembly is fixed to the housing, no relative movement occurs between the system section of the axial play compensation device and the corresponding bearing assembly.

[0015] A further aspect of the invention relates to the possibility of additionally fixing or positioning the stator in the circumferential direction relative to its longitudinal axis. For this purpose, the axial play compensation device is additionally designed to prevent rotation of the stator about its longitudinal axis, in particular by means of at least one further contact point between the axial play compensation device and the stator.

[0016] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing.

[0017] This shows in: Fig. 1 a longitudinal section through a windshield wiper motor in a first embodiment of an axial backlash compensation device, Fig. 2 and Fig. 3 partial longitudinal sections through the windshield wiper motor according to Fig. 1 in modified axial play compensation devices, Fig. 4 a cross-section through a windshield wiper motor with a further modified axial backlash compensation device and Fig. 5 a perspective view of a section of the windshield wiper motor according to the Fig. 4 in the connection area between the axial play compensation device and an extension of a connecting body.

[0018] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0019] The one in Fig. The windshield wiper motor 100 shown serves to move, at least indirectly, a wiper arm (not shown) with a wiper blade of a windshield wiper system of a vehicle. For this purpose, the windshield wiper motor 100 has an output shaft 12 which is coupled via a toothed connection 14 to a wiper arm or a wiper linkage for driving at least one wiper arm.

[0020] The windshield wiper motor 100 comprises a brushless electric motor 10. The electric motor 10 has an annular stator 16 with a longitudinal axis 18. The stator 16 further comprises a plurality of stacked and interconnected stator laminations 20, which form a stator body 24 and which serve for the attachment or reception of components located only in the Fig. The stator body 24 serves as a connection point for the wire windings 22, as is known from the prior art. The stator body 24 is connected at one end face to a terminal body 26, which is also essentially ring-shaped. The terminal body 26, which serves for the electrical contact of the wire windings 22, is made of plastic and is designed as an injection-molded part.

[0021] On the side facing away from the stator laminations 20, a projection 28 extends from the terminal body 26, running parallel to and at a distance from the longitudinal axis 18. At the end region of the projection 28 facing away from the stator laminations 20, first electrical connection elements 30, designed as clamping elements or similar, are provided in the trough-shaped projection 28. These first electrical connection elements 30 are connected to the wire windings 22 on one side and can be contacted via second electrical connection elements 32 on the other, in order to drive the windshield wiper motor 100 or the electric motor 10. For this purpose, the second connection elements 32 are, for example, integrated into a housing cover 34, which, by being joined in a mounting direction 36 perpendicular to the longitudinal axis 18, enables positive contact between the first and second connection elements 30, 32.The contact between the terminal elements 30, 32 takes place outside the area of ​​a housing 46 in which the stator 16 with the stator body 24 and the wire windings 22 are arranged.

[0022] In the illustrated embodiment, the extension 28 has a rectangular cross-section in its outer cross-section and a constant outer cross-section in the longitudinal direction.

[0023] The stator 16 interacts with a rotor 38 arranged concentrically to the longitudinal axis 18. The rotor 38 has a shaft 40, which is rotatably mounted in a housing 46 of the electric motor 10 or the windshield wiper motor 100 by means of two axially spaced bearing arrangements 42, 44. The axis of rotation 48 of the rotor 38 is aligned with the longitudinal axis 18 of the stator 16. In the overlap area with the wire windings 22, the rotor 38 also has several permanent magnet elements, in a known manner (not shown), which cause the rotor 38 to rotate about the axis of rotation 48 when the stator windings 22 are energized at different times. To detect the rotational position of the rotor 38 for timely control, the rotor 38 is equipped with a sensor.In addition to the current supply to the wire windings 22, a magnetic ring 50 with magnetic elements 52 is arranged on the circumference of the rotor 38, which is for example part of a Hall sensor device in order to be able to deduce the rotational angular position of the rotor 38 or the shaft 40.

[0024] In an area between the two bearing devices 42, 44, the shaft 40 also has a worm gear 54 which meshes with a mating gear 56 on the outer circumference of a spur gear 58, which in turn is at least indirectly coupled to the output shaft 12.

[0025] The multi-part housing 46 of the windshield wiper motor 50 includes a housing cover 60 at its end face for closing a cup-shaped receptacle 62 for the stator 16. The receptacle 62 has a geometry radially circumferential around the longitudinal axis 18 with a step 64, against which the stator 16, for example with the stator laminations 20, rests axially on one side, so that the step 64 forms an axial stop for axially positioning the stator 16 in the housing 46.

[0026] To prevent noise, particularly when the direction of rotation of the electric motor 16 is reversed, and to compensate for any assembly play, the electric motor 10 also has an axial play compensation device 66. The axial play compensation device 66 is designed as a sheet metal component. The component is elastically deformable, at least in some areas, and is manufactured by a stamping and bending process. It also has a U-shaped opening or receptacle 68, which is designed to partially encompass the shaft 40 around its outer circumference. The axial play compensation device 66 is received in a receptacle 70 of the housing 46 by means of a clamping connection, such that one end face of the axial play compensation device 66 is supported against a housing wall 72 and the other end face rests against the first bearing assembly 42.For mounting the axial play compensation device 66, it can be inserted into the receptacle 70 in a direction perpendicular to the axis of rotation 48, or in the mounting direction 36. This subjects the shaft 40, which is rotationally fixed to the first bearing assembly 42, to an axial force, for example, in the direction of the second bearing assembly 44.

[0027] The axial play compensation device 66 has, on the side facing away from the shaft 40, a first section 73 projecting obliquely away from the stator 16, to which a second section 74 adjoins, running parallel to the axis of rotation 48. The upper surface of the second section 74 rests against the lower surface 75 of the extension 28, thereby forming an axial stop for the extension 28 in the direction of the shaft 40 or in the mounting direction 36. Furthermore, the axial play compensation device 66 has a contact section 76 parallel to the axis of rotation 48, which rests against the outer circumference of the first bearing assembly 42 and limits the movement of the axial play compensation device 66 in the mounting direction 36 during installation in the receptacle 68.

[0028] The contact between the axial play compensation device 66 and the extension 28 ensures that, when the second connecting elements 32 are installed, the extension 28 cannot move towards the shaft 40. Furthermore, this also ensures that the stator 16 is positioned in the housing 46 in a direction perpendicular to the axis of rotation 48 or longitudinal axis 18, thus preventing the stator 16 from tilting within the housing 46.

[0029] The one in Fig. The axial play compensation device 66a shown in Figure 2 differs from the axial play compensation device 66 according to the Fig. 1. The contact between the axial play compensation device 66a and the underside 75 of the extension 28 is provided in the area of ​​a section 78 running parallel to the axis of rotation 48, which is longer than the second section 74 of the axial play compensation device 66. Furthermore, a contact section 80, arranged perpendicular to the axis of rotation 48, projects from the section 78 such that the end face 82 of the extension 28 facing away from the stator laminations 20 bears axially against the section 80. The axial play compensation device 66a thus limits the movement of the stator 16 in the direction of the longitudinal axis 18. This, in turn, means that the housing 46a can be simplified in that, for example, no step 64 or axial stop for the stator surface 20 needs to be provided.

[0030] The one in Fig. The axial play compensation device 66 shown in Figure 3 is identical to the axial play compensation device 66 of the Fig. 1. However, an extension 28a is provided, which is supplemented by an additional stop element 84, preferably monolithically formed on the extension 28a. The stop element 84 acts as an axial stop for the axial backlash compensation device 66, so that in this case movement of the stator 16 in the direction of arrow 86, i.e. from the step 64 in the housing 46, is prevented.

[0031] Most recently, in the Fig. 4 and Fig. Figure 5 shows a further embodiment of an extension 28b. On the side facing the two legs 88, 90 of the axial play compensation device 66b, which define the receptacle 68, this extension has two recesses 92, 94 against which the legs 88, 90 of the axial play compensation device 66b bear. This creates at least two contact points 96, 98 between the axial play compensation device 66b and the extension 28b in the circumferential direction of a partial circle diameter around the longitudinal axis 18 of the stator 16, which are arranged at a horizontal distance from each other. Such an embodiment, in particular, prevents rotation of the [unclear text] in the Fig. 4 and Fig. 5 stator 16 not shown about its longitudinal axis 18 is prevented, since the recesses 92, 94, depending on the direction of rotation of the stator 16 about the longitudinal axis 18, come into contact with the contact contacts 96, 98 on a side surface of the respective leg 88, 90.

[0032] The electric motor 10 or windshield wiper motor 100 described so far can be modified or adapted in a variety of ways without deviating from the inventive concept. Reference symbol list 10 Electric motor 12 Output shaft 14 gear teeth 16 Stator 18 Longitudinal axis 20 stator laminations 22 wire windings 24 Stator bodies 26 connection bodies 28, 28a, 28b continuation 30 first connection element 32 second connection element 34 Housing covers 36 Mounting direction 38 runners 40 wave 42, 44 Storage facility 46, 46a Housing 48 Rotary axis 50 magnetic rings 52 magnetic elements 54 worm gear 56 Counter-gearing 58 Spur gear 60 Housing covers 62nd recording Level 64 66, 66a, 66b Axial backlash compensation device 68 recording 70 recordings 72 Housing wall 73 first section 74 second section 75 Underside 76 Plant section Section 78 80 Plant section 82 Front 84 Stop element 86 Arrow 88, 90 thighs 92, 94 In-depth study 96, 98 Investment contact 100 windshield wiper motors

Claims

[1] Brushless electric motor (10), in particular for a windshield wiper motor (100), with a stator (16) that is at least substantially ring-shaped, wherein the stator (16) interacts with a rotatably mounted rotor (38) arranged concentrically to the stator (16), wherein a shaft (40) of the rotor (38) is rotatably mounted by means of at least two bearing devices (42, 44), wherein the rotor (38) is mounted axially backlash-free in the direction of an axis of rotation (48) of the shaft (40) in a housing (46; 46a) of the electric motor (10) by means of an axial backlash compensation device (66; 66a; 66b), wherein the stator (16) is positioned by contact with a component in a direction perpendicular to the axis of rotation (48) of the shaft (40) towards the housing (46; 46a), wherein the component for forming the contact with the stator (16) Axial play compensation device (66; 66a;66b), wherein the stator (16) has a stator body (24) carrying wire windings (22) and a terminal body (26) at least indirectly connected to the stator body (24) for electrically contacting the wire windings (22), wherein the terminal body (26) is arranged on an end face of the stator body (36), wherein the terminal body (26) has a projection (28; 28a; 28b) extending parallel to the longitudinal axis (18) of the stator (16) and arranged on the side facing away from the stator body (24), and wherein the projection (28; 28a; 28b) is arranged in contact with the axial backlash compensation device (66; 66a; 66b), ; characterized by , that the stator (16) is fixed in the housing (46a) in a direction parallel to its longitudinal axis (18), and that the fixing is effected by means of the axial play compensation device (66; 66a; 66b) by contact with the extension (28; 28a; 28b). [2] Brushless electric motor according to claim 1, characterized by, that the connecting body (26) is made of plastic and is designed as an injection-molded part. [3] Brushless electric motor according to claim 1 or 2, characterized by , that the axial play compensation device (66; 66a; 66b) is designed in the form of an elastically deformable element, in particular made of sheet metal, which has a U-shaped opening (68) for receiving the shaft (40), and which can be mounted in a receptacle (70) of the housing (46; 46a) in a direction perpendicular to the axis of rotation (40) of the shaft (40), so that a clamping connection is formed between the axial play compensation device (66; 66a; 66b) and the shaft (40), in which the axial play compensation device (66; 66a; 66b) exerts force on the shaft (40) in the direction of a bearing device (42). [4] Brushless electric motor according to claim 3, characterized by, that the contact between the axial play compensation device (66; 66a; 66b) and the extension (28; 28a; 28b) is formed on a side of the axial play compensation device (66; 66a; 66b) facing away from the opening (68). [5] Brushless electric motor according to claim 3 or 4, characterized by , that the contact between the axial play compensation device (66; 66a; 66b) and the extension (28; 28a; 28b) is formed in a region of the opening (68) on the axial play compensation device (66; 66a; 66b) spaced apart in the direction of the axis of rotation (48) of the shaft (40). [6] Brushless electric motor according to claim 5, characterized by , that the contact is formed on a section (74; 78) of the axial play compensation device (66; 66a; 66b) running parallel to the axis of rotation (48) of the shaft (40). [7] Brushless electric motor according to any one of claims 3 to 6, characterized by, that the axial play compensation device (66; 66a; 66b) has a mounting section (76) for forming a stop in a mounting direction of the axial play compensation device (66; 66a; 66b) perpendicular to the axis of rotation (48) of the shaft (40). [8] Brushless electric motor according to claim 7, characterized by , that the plant section (76) is arranged in operative connection with an outer circumference of a storage facility (42). [9] Brushless electric motor according to any one of claims 1 to 8, characterized by , that the stator (16) is fixed in the housing (46) in a direction parallel to its longitudinal axis (18) by a geometry (64) provided in the housing (46) which forms an axial stop. [10] Brushless electric motor according to claim 1, characterized by, that the axial play compensation device (66a) has a section (80) extending perpendicular to the axis of rotation (48) of the shaft (40), which rests against the extension (28) on the side facing away from the stator (16). [11] Brushless electric motor according to claim 1, characterized by , that the extension (28a) has a stop (84) extending in the direction of the axis of rotation (48) of the shaft (40), against which the axial play compensation device (66) rests. [12] Brushless electric motor according to any one of claims 1 to 11, characterized by , that the contact between the axial play compensation device (66; 66a; 66b) and the extension (28; 28a; 28b) takes place outside an area of ​​the housing (46; 46a) that accommodates the stator body (24) and the wire windings (22). [13] Brushless electric motor according to any one of claims 1 to 12, characterized by, that the axial play compensation device (66b) is additionally designed to prevent rotation of the stator (16) about its longitudinal axis (18), in particular by at least two contact contacts (96, 98) arranged at a distance from each other between the axial play compensation device (66b) and the stator (16).

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