US-12620848-B2 - Stator body for an axial flux electric machine

US12620848B2US 12620848 B2US12620848 B2US 12620848B2US-12620848-B2

Abstract

A stator body for an axial-flux electric machine includes: a plate in the form of a ring centered on a longitudinal axis, the plate including an upper face and at least one upper relief projecting from the upper face; and teeth, at least one of which includes a lower relief, a first side of which has a shape complementary to that of a portion of the upper relief, the upper relief being interlocked with the lower relief. The body includes a locking element extending opposite the upper face of the plate and interposed between the tooth and the plate so as to immobilize the upper relief in the position interlocked with the lower relief, and blocking unit blocking the position of the locking element with respect to the plate.

Inventors

Jere Kolehmainen

Assignees

RENAULT S.A.S.
WHYLOT

Dates

Publication Date: 20260505
Application Date: 20220513
Priority Date: 20210514

Claims (10)

1 . A stator body for an axial-flux electric machine comprising: a ring-shaped plate centered on a longitudinal axis, the ring-shaped plate comprising an upper face and at least one upper relief projecting from the upper face; teeth at least one of which comprises a lower relief a first side of which has a shape complementary to that of a portion of the upper relief, the upper relief being interlocked with the lower relief; wherein the body comprises a locking element extending opposite the upper face of the ring-shaped plate and interposed between the tooth and the ring-shaped plate so as to immobilize the upper relief in an interlocked position with the lower relief and wherein the body comprises blocking means blocking the position of the locking element with respect to the ring-shaped plate, wherein the locking element comprises a notch in which the upper relief and the lower relief are located, the notch having a lateral edge forming, together with the lower relief and the upper relief, a dovetail assembly wherein the lower relief forms a tenon and wherein the lateral edge of the notch and the upper relief form a mortise.
2 . The stator body according to claim 1 , wherein the locking element is designed, before assembly, to pivot relative to the ring-shaped plate between a released position in which the tooth is movable relative to the ring-shaped plate and a blocking position in which the locking element immobilizes the upper relief by holding the upper relief interlocked with the lower relief, the blocking means being adapted to hold the locking element in the blocking position.
3 . The stator body according to claim 1 , wherein the blocking means comprise at least one amongst the following elements: a screw; a snap-fit device.
4 . The stator body according to claim 1 , wherein the upper relief comprises an upper rib and wherein the lower relief comprises a lower rib.
5 . The stator body according to claim 4 , wherein each of the upper rib and the lower rib has a uniform profile according to a radial direction perpendicular to the longitudinal axis.
6 . The stator body according to claim 4 , wherein the upper relief has a main surface directed towards the ring-shaped plate and wherein the lower relief has a first surface directed towards the tooth, the main surface being in contact with the first surface.
7 . The stator body according to claim 1 , wherein the body comprises a wall rising from a peripheral edge of the ring-shaped plate, on the side of the ring-shaped plate's upper face, the wall having a groove a portion of which extends lengthwise according to an axis orthogonal to the longitudinal axis, the locking element having a peripheral relief which is inserted into the portion of the groove.
8 . A stator comprising a stator body according to claim 1 and conductive wire windings carried by the teeth.
9 . A method for assembling a stator body according to claim 1 , comprising the following steps of: positioning the locking element on the upper face of the ring-shaped plate; positioning the tooth so that the upper relief interlocks with the lower relief; moving the locking element relative to the ring-shaped plate; blocking the locking element with respect to the ring-shaped plate by means of the blocking means.
10 . The method according to claim 9 , wherein the locking element pivots relative to the ring-shaped plate between a released position in which the tooth is movable relative to the ring-shaped plate and a blocking position in which the locking element immobilizes the upper relief by holding the upper relief interlocked with the lower relief, the blocking means being adapted to hold the locking element in the blocking position.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is the US national stage of PCT/EP2022/063076, filed May 13, 2022 and designating the United States, which claims the priority of FR FR2105077, filed May 14, 2021. The entire contents of each foregoing application are incorporated herein by reference. TECHNICAL FIELD OF THE INVENTION The present invention generally relates to the field of electric machines. More particularly, it relates to a stator body for an axial-flux electric machine comprising: a ring-shaped plate centred on a longitudinal axis, the plate comprising an upper face and at least one upper relief projecting from the upper face;teeth at least one of which comprises a lower relief, a first side of which has a shape complementary to that of a portion of the upper relief, the upper relief being interlocked with the lower relief. The invention finds a particularly advantageous application in electric or hybrid motor vehicles. It also relates to a stator comprising such a stator body as well as a method for assembling such a stator body. PRIOR ART A conventional stator body of an axial-flux electric machine comprises a generally annular plate and teeth circumferentially distributed over an upper face of the plate. To make a stator starting from this body, conductive wire coils are arranged around the teeth. Under the effect of electric currents, the coils generate magnetic fields enabling the stator to set a rotor in motion. One way to simplify winding of the conductive wire around the teeth is to make the plate and the teeth separately, and then wind the conductive wire around each tooth and finally attach the teeth to the plate. To improve fastening of the teeth to the plate, each tooth may have a relief designed to fit into another relief with a partially complementary shape located on the upper face of the plate. In particular, a stator body is known from the document WO2017/121941 whose plate has a plurality of radial grooves and wherein each tooth has a rib adapted to fit into one of the radial grooves. Each tooth is then connected to the plate by a slide connection forming a dovetail assembly. Nonetheless, for the teeth to be able to be put in place (for example the radial insertion thereof in the case of the aforementioned document), the reliefs of the teeth and those of the plate should then fit together, which requires providing for a slight clearance. Hence, fitting cannot be as tight as necessary. The stator body thus obtained is not as rigid as desired meaning that the teeth could actually undergo small movements since fastening thereof to the plate features a slight clearance. DISCLOSURE OF THE INVENTION In order to overcome the aforementioned drawback of the prior art, the present invention provides a stator body as defined in the introduction, wherein it is provided that the body comprises a locking element extending opposite the upper face of the plate and interposed between the tooth and the plate so as to immobilise the upper relief in a position interlocked with the lower relief and that the body comprises blocking means blocking the position of the locking element with respect to the plate. Thus, thanks to the invention, the lower relief of the tooth is securely held interlocked with the upper relief of the plate by the locking element. By blocking the locking element with respect to the plate, the blocking means prevent the detachment of the upper relief and of the lower relief. The body of the stator is then rigid meaning that it is impossible to move the tooth relative to the plate, even slightly. In particular, the invention allows obtaining a compact and rigid stator body without having to use glue or welding. Of course, gluing or welding operations could be implemented afterwards to apply on the stator body a product allowing increasing thermal conductivity between the components of the stator. Other advantageous and non-limiting features of the stator body in accordance with the invention, considered separately or according to any technically-feasible combination, are as follows: the locking element is designed, before assembly, so as to pivot relative to the plate between a released position in which the tooth is movable relative to the plate and a blocking position in which the locking element immobilises the upper relief by holding it interlocked with the lower relief, the blocking means being adapted to hold the locking element in the blocking position;the blocking means comprise at least one amongst the following elements: a screw, a snap-fitting device;the locking element comprises a notch in which the upper relief and the lower relief are located, the notch having a lateral edge forming, together with the lower relief and the upper relief, a dovetail assembly wherein the lower relief forms a tenon and wherein the lateral edge of the notch and the upper relief form a mortise;the upper relief comprises an upper rib and the lower relief comprises a lower rib