Electric Motor With A Stator And An Axle That Can Be Press-Fitted Thereto

Abstract

An electric motor with a stator and an axle (20). The stator has a laminated stator core (10) formed from a multitude of individual teeth (11). At least some of the individual teeth (11) each have a radially inner pressing portion (13) for elastic and/or plastic deformation and establishment of a press-fit connection between the laminated stator core (10) and the axle (20). The stator is fixed to the axle (20) through the deformation of the pressing portions (13) and a force acting on the axle (20). At least one securing element (30) is on at least some of the pressing portions (13) to transmit a torque between the axle (20) and the laminated stator core (10) and fix the position of the laminated stator core (10) relative to the axle (20) in the circumferential direction (U).

Claims

1-10. (canceled)

11. An electric motor with a stator and an axle, the stator has a laminated stator core formed from a multitude of individual teeth that can be arranged in a ring around an axis of rotation of the electric motor and are interconnected in the circumferential direction, at least some of the individual teeth each have a radially inner pressing portion for elastic and/or plastic deformation and establishment of a press-fit connection between the laminated stator core and the axle, the inner pressing portions extend through the laminated stator core along the axis of rotation and coaxially with the axis of rotation, upon joining of the stator to the axle, the stator can be fixed to the axle through the deformation of the pressing portions and a force acting on the axle as a result of the deformation between laminated stator core and axle, and the electric motor has at least one securing element, a respective securing element being provided on at least some of the pressing portions and designed to transmit a torque between the axle and the laminated stator core and to fix the position of the laminated stator core relative to the axle in the circumferential direction.

12. The electric motor as set forth in claim 11, wherein at least the pressing portions, where a securing element is provided, each have a first groove that faces toward the axle and extends parallel to the axis of rotation and receives a respective securing element.

13. The electric motor as set forth in claim 12, wherein the axle has at least one second groove facing toward the laminated stator core and extends parallel to the axis of rotation, the securing element is inserted in a form-fitting and/or frictional manner into a receiving space that is formed jointly by the at least one first groove and the at least one second groove.

14. The electric motor as set forth in claim 13, wherein the at least one first groove fixes a respective securing element in the first groove in the radial direction, so that the securing element is fixed in the radial direction on the pressing portion.

15. The electric motor as set forth claim 11, wherein the securing element is a securing pin.

16. The electric motor as set forth in claim 11, wherein the axle has at least one third groove that faces toward the laminated stator core and extends parallel to the axis of rotation, at least one individual tooth integrally forms the at least one securing element in its pressing portion, faces toward the axle, and extends parallel to the axis of rotation, and the securing element that is formed integrally by the individual tooth can be inserted in a form-fitting manner into a receiving space that is formed by the at least one third groove.

17. The electric motor as set forth in claim 11, wherein the pressing portions each have a web extending in the radial direction and two lever arms that are connected to the web and protrude oppositely to one another in the circumferential direction relative to the web, each lever arm has a contact surface that points inward in the radial direction for contact with the axle, and the two lever arms can be deflected and deformed in the radial direction during the joining process so that a pressing force can be exerted on the axle as a result of the deflection and deformation.

18. The electric motor as set forth in claim 17, wherein the lever arms together define a sleeve-shaped pressing contour with their contact surfaces that is coaxial with the axis of rotation and oversized compared to an outer contour of the axle so that the lever arms are pressed radially outward when joined to the axle.

19. The electric motor as set forth in claim 17, wherein a respective securing element is provided between the two lever arms.

Description

DRAWINGS

[0042] Other advantageous refinements of the disclosure are characterized in the subclaims and/or depicted in greater detail below together with the description of the preferred embodiment of the disclosure with reference to the figures. In the drawings:

[0043] FIG. 1 is a perspective view of a laminated stator core that is joined to an axle;

[0044] FIG. 2 is a plan view of a cut-out formed of laminated stator core that is joined to an axle;

[0045] FIG. 3 is a detailed plan view of a pressing portion of an individual tooth of a laminated stator core that is joined to an axle;

[0046] FIG. 4 is a perspective view of an axle; and

[0047] FIG. 5 is a detailed plan view of an alternative embodiment of a pressing portion of an individual tooth of a laminated stator core that is joined to an axle.

[0048] The figures are schematic examples. Same reference symbols in the figures indicate same functional and/or structural features.

DETAILED DESCRIPTION

[0049] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0050] FIG. 1 shows an electric motor perspective view of a laminated stator core 10 of an electric motor that is joined to an axle 20. If, as is the case here, a laminated stator core 10 is formed from a multitude of individual teeth 11 that are interconnected in the circumferential direction U, it is possible during joining of the laminated stator core 10 to the axle 20 for impermissibly high forces to occur in the region of the connection portions 12 where the Individual teeth 11 are mechanically interconnected or fixed to one another in the circumferential direction U. This results in the release of the mechanical connection and separation of the individual teeth 11 from one another. This may dismantle or even damage the laminated stator core 10.

[0051] In order to prevent such dismantling or damage to the laminated stator core 10, at least some of the individual teeth 11 and—especially preferably, as shown in FIGS. 1 to 3—all of the individual teeth 11 have a pressing portion 13. The pressing portion 13 is designed to join the laminated stator core 10 to the axle 20.

[0052] The pressing portion 13 is located radially to the axis of rotation R about which a rotor of the electric motor can rotate around the stator, on the inside, and closes off the individual teeth 11 in the radial direction X inward or toward the axle 20.

[0053] FIG. 2 corresponds to a detail of a plan view of the laminated stator core 10 with the axle 20 joined, as illustrated by FIG. 1. This makes it particularly clear that the laminated stator core 10 is in contact with the axle 20 exclusively through the pressing portions 13 of the individual teeth 11 of the laminated stator core 10. The pressing portions 13 of the individual teeth 11, together, define a sleeve-shaped pressing contour that corresponds to the outer contour of the axle 20 but is oversized relative thereto. Due to the oversize, the axle 20 can be arranged in and pressed into the pressing contour formed by the pressing portions 13. Thus, a deformation of the pressing portions 13 or a deformation of the lever arms 15 of the pressing portions 13, shown in FIG. 3, occurs during the pressing-in. The lever arms 15 are pressed radially outward and exert a pressing force on the axle 20.

[0054] Since a torque acts on the stator during operation of the electric motor, the stator or, more particularly, the laminated stator core 10 must be fixed around the axis of rotation R in the circumferential direction. According to the variant shown in FIGS. 1 to 4, second grooves 32 are included and distributed uniformly in the circumferential direction U on the axle 20. The second grooves 32 each correspond to the first grooves 31 on the pressing portions 13. Here, on all of the pressing portions 13, the first groove 31 of each second individual tooth 11 forms a receiving space with a respective second groove 32 to receive a securing element 30.

[0055] In the variant shown in FIGS. 1 to 4, the securing element 30 is a cylindrical securing pin that can be inserted parallel to the axis of rotation R into a receiving space that is formed by a first groove 31 and a second groove 32. The first groove 31 is designed so that it encompasses greater than 50% of the round outer contour of the securing element 30. Thus, the securing pin or the securing element 30 is held or fixed in the radial direction X by the first groove 31.

[0056] FIG. 3 shows an enlarged view of an individual pressing portion 13 with a securing element 30. This clarifies that the pressing portion 13 is terminated radially inward by two lever arms 15. The lever arms 15 are separated from one another by the first groove 31. Each lever arm 15 is connected to the web 14 by a taper or a connection portion 18.

[0057] The connection portions 18 and the groove 31 enable the lever arms 15 to deflect independently of one another. Each lever arm 15 has a free end opposite their end that merges into the connection portion 18. Thus, when they are joined to the axle 20, they initially yield elastically and can be plastically deformed preferably at the end of the elastic deformation.

[0058] The lever arms 15 each have a contact surface 16 to contact with the axle 20. Each of the contact surfaces 16 or the two contact surfaces 16 of the pressing portion 13, together, describing a concave shape or possibly being concave. The two contact surfaces 16 provide two contact regions or contact points for each pressing portion 13 via which the respective individual tooth 11 rests against the axle 20.

[0059] In order to prevent the individual teeth 11, that are interconnected at the connection portions 12, from being separated from one another when the axle 20 is joined, pressed into the stator or into the pressing contour formed by the pressing portions 13, the connection portions 18 are embodied such that, during joining and an associated deflection of the lever arms 15 at the connection portions 12, a force acts, which is smaller than a maximum permissible force, by which the individual teeth 11 at the connection portions 12 would be separated from one another.

[0060] FIG. 4 shows an axle 20 with second grooves 32 distributed in the circumferential direction U as can be employed in the variant shown in FIGS. 1 to 3. The axle 20 has a portion where the second grooves 32 extend and which determines the outer contour 21 that is relevant to the press-fit connection. Furthermore, the axle 20 forms a chamfer or insertion bevel 23 that centers the axle 20 in the laminated stator core 10 when it is pushed or pressed into the latter. The axle 20 has a contact surface 22 in order to limit the insertion or press-in depth of the securing elements 30 into the respective receiving spaces. The securing elements 30 come to rest on the contact surface 22 upon insertion.

[0061] FIG. 5 depicts an alternative embodiment where at least some of the pressing portions 13 or at least some of the individual teeth 11 integrally form the securing element 30. The securing element 30 has a projection that protrudes in the radial direction X relative to the lever arms 15. The projection or the securing element 30 is flanked on both sides by a groove. The groove enables the lever arms 15 to be further deformed independently of one another and independently of the securing element 30 during joining of the laminated stator core 10 to the axle 20.

[0062] Each individual tooth 11 or, for example, every other individual tooth 11 can have such a securing element 30. In this case, the axle has a corresponding third groove 33 for each securing element 30.

[0063] Furthermore, the axle 20 can have additional insertion bevels 24 on the third grooves 33 in order to facilitate joining. Thus, the securing elements 30 are guided into the corresponding groove 33 during the joining process.

[0064] The disclosure is not limited in its execution to the abovementioned preferred exemplary embodiments. Rather, a number of variants are conceivable that make use of the illustrated solution even in the form of fundamentally different embodiments.

[0065] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.