METHOD FOR FITTING A STATOR INTO A HOUSING, INCLUDING ROUNDED ANGLE MACHINING AND CUTTING OF STATOR SHEETS, STATOR, HOUSING, VEHICLE AND PROGRAM BASED ON SUCH A METHOD

Abstract

The invention relates to a shrink-fit method for an electrical machine stator (S) in a housing (C), comprising: - a machining step of a receiving portion (R) of the housing (C) to create a rounded corner junction surface (J); - a trimming step in which the size of the peripheral laminations (TP) is reduced relative to that of the central laminations (TC) forming the stator (S); and - a shrink-fitting step of the stator (S) in the housing (S) such that the laminations (TC, TP) bear against the shoulder portion (E), and the peripheral laminations (TP) are not in contact with the bottom wall (F) of the housing (C). The invention also relates to a stator, a housing, a vehicle, and a program based on such a method. Figure 4

Description

Title of the invention: METHOD FOR FITTING A STATOR INTO A HOUSING, COMPRISING ROUNDED ANGLE MACHINING AND CUTTING OF STATOR SHEETS, STATOR, HOUSING, VEHICLE AND PROGRAM BASED ON SUCH A METHOD

[0001] The invention relates to the field of shrink-fitting processes for stators of electric motor vehicle machines.

[0002] The electrical machines that equip the electromotor sets are currently equipped with so-called "active" parts, mainly consisting of a rotor and a stator.

[0003] The stator S, a fixed component of the active parts illustrated in figures 1 to 3, is generally introduced inside a main housing C, by a manufacturing process called "shrink fitting".

[0004] This method allows the stator S to be introduced and then, by differential expansion, immobilized in rotation within the main casing C of the electric machine.

[0005] To do this, the main housing C is preheated by induction to a temperature of around 200°C, which significantly increases the internal diameter in which the stator S must fit, so that the latter can slide freely without any radial constraint.

[0006] The main housing C is then placed vertically and immobilized by clamping on a plate P of the shrink-fitting station.

[0007] An expanding chuck then grasps the stator S by its inner diameter, to come, by means of a sliding plate, to house it inside the main casing C.

[0008] The axial position of the stator S is achieved using a shoulder E, made by machining in the main housing C.

[0009] In order to ensure a precise position of the stator S in the main housing C, the creation of a clearance or "water drop" G is necessary in the prior art.

[0010] In general, the stator S consists of n stacks, themselves made from stacks of cut TC sheets, of thickness between 0.25 and 0.5 mm, and of identical diameter.

[0011] Unfortunately, this machining requires a lot of cycle time, changeover of the tool and its durability.

[0012] On the other hand, when the stator S returns to room temperature, there may be a risk of locally deforming the stator S at the stacking of the sheets constituting it.

[0013] An objective of the present invention is to remedy the defects of the prior art, and in particular to offer an easy and quick shrink-fitting solution, limiting the risk of locally deforming the stator.

[0014] To achieve this objective, the invention proposes a method for shrink-fitting an electrical machine stator in a housing comprising a cylindrical shoulder portion and a blind receiving portion including a bottom wall, receiving the stator, the stator being cylindrical with a base cooperating with the receiving part, the stator comprising central and peripheral straight laminations with reference to the axis of the cylindrical stator, the stator being designed to be coaxial with the casing, the stator being in a frame of reference in space comprising a longitudinal axis following the central axis of the cylindrical stator and a longitudinal direction of the laminations, a lateral axis perpendicular to the longitudinal axis, and a transverse axis perpendicular to the longitudinal axis and the lateral axis, The shrink-fitting process includes the following steps: - a machining step in which the receiving part of the housing is machined so as to create a rounded corner joining surface between the cylindrical shoulder part and the bottom wall; - a trimming step in which the length of the peripheral sheets along the longitudinal axis is less than that of the central sheets; and - a shrink-fitting step of the stator in the housing so that the laminations rest on the shoulder section, and the peripheral laminations have a distance from the bottom wall of the housing

[0015] Advantageously, the invention facilitates shrink fitting because machining the receiving part is easier and faster than machining in the prior art. The creation of a relief or "water drop" G is no longer necessary thanks to the invention.

[0016] In addition, the invention does not require heating and cooling of the stator, which limits the risk of locally deforming the stator.

[0017] According to one embodiment, the joining surface has a tangent radius between 0.5 mm and 10 mm. Preferably the joining surface has a tangent radius of 0.7 mm.

[0018] This makes it easier to insert the stator and to apply the constraint of the stator against the housing.

[0019] According to one variant, the axis of the shoulder part is parallel to the sheets.

[0020] This allows for uniform support of the sheets on the shoulder perpendicular to the longitudinal axis of the sheets.

[0021] According to one variant, the stator comprises fewer peripheral laminations than laminations power plants.

[0022] This allows the majority of the sheet metal to be supported on the bottom wall.

[0023] The invention further relates to a motor vehicle stator obtained by a shrink-fitting process according to the invention, the stator being cylindrical and comprising central and peripheral straight sheets with reference to the axis of the cylindrical stator, characterized in that the sheets are notched so that the length of the peripheral sheets is less than that of the central sheets; and in that the peripheral plates are configured to present a distance from the bottom wall of the casing.

[0024] Another object of the invention relates to a motor vehicle stator housing, obtained by a shrink-fitting process according to the invention, the housing comprising a cylindrical shoulder portion and a blind receiving portion comprising a bottom wall, configured to receive a stator, characterized in that the housing comprises a receiving portion machined so as to produce a rounded angle joining surface between the cylindrical shoulder portion and the bottom wall.

[0025] The invention further relates to a motor vehicle comprising a casing and a stator obtained by the shrink-fitting process according to the invention.

[0026] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates a shrink-fitting station implementing a shrink-fitting process according to the prior art; - [Fig.2] schematically illustrates an assembly of a stator in a housing with clearance according to the prior art; - [Fig.3] schematically illustrates the release housing of the process according to the prior art; - [Fig. 4] schematically illustrates an assembly of a stator in a housing without clearance according to the invention; and - [Fig.5] schematically illustrates the housing without clearance of the process according to the invention.

[0027] The invention relates to a shrink-fitting method for a stator of an electric machine in an automobile.

[0028] The stator S must be inserted into a housing C. The housing C has a cylindrical shoulder portion E and a blind receiving portion R continuous with the shoulder portion E. The receiving portion R includes a bottom wall F, and receives the stator S.

[0029] The stator S is cylindrical with a base cooperating with the receiving wall R. The The stator S comprises straight laminations. We distinguish between central laminations TC close to the central axis of the stator S, and peripheral laminations TP further from said axis.

[0030] The stator S is intended to be coaxial with the housing C once inserted into the housing C.

[0031] The stator S is defined in a frame of reference in space comprising a longitudinal axis X along the central axis of the cylindrical stator S and a longitudinal direction of the laminations TC, TP, a lateral axis Y perpendicular to the longitudinal axis X, and a transverse axis Z perpendicular to the longitudinal axis X and to the lateral axis Y.

[0032] In particular, the axis of the shoulder part E is parallel to the sheets TC, TP.

[0033] The proposed solution is as follows. At the end of the stator S, resting on the shoulder E, intended to ensure its axial position during the shrink-fitting operation, it is proposed to simplify the machining into a tangent radius RT which can then be directly obtained by the radius of the insert of the tool making the shrink-fitting diameter of the stator S in the main housing C.

[0034] In addition, it is proposed to minimize the diameter of the first peripheral sheets TP constituting the stator S, so that it can bear on the shoulder E, the bearing surface meeting a predefined minimum value.

[0035] Thus, the shrink-fitting process includes a machining step in which the receiving part R of the housing C is machined so as to produce a junction surface J with a rounded angle between the cylindrical shoulder part E and the bottom wall F.

[0036] In particular, the junction surface J has a tangent radius illustrated in [Fig.5], between 0.5 mm and 10 mm, preferably 0.7 mm.

[0037] The rounded corner is inscribed in the extension of the bottom wall and the shoulder part, so that there is no clearance or drip edge of the prior art (illustrated in figures 2 and 3).

[0038] The shrink-fitting process further includes a trimming step in which the size of the peripheral sheets TP, in particular their diameters in the preferred arrangement, is reduced relative to that of the central sheets TC, so that once the stator S is inserted into the housing C, the peripheral sheets TP will not be in contact with the bottom wall F of the housing C.

[0039] In particular, a minority of peripheral sheets TP have a reduced size, compared to the central sheets TC.

[0040] The shrink-fitting process further includes a shrink-fitting step of the stator S in the housing S so that the sheets TC, TP are in contact with the shoulder part E, and the peripheral sheets TP are not in contact with the bottom wall F of the housing C.

[0041] The invention further relates to the corresponding control program, as well as a shrink-fitting installation comprising such a control program.

Claims

Demands

1. A method for shrink-fitting an electrical machine stator (S) in a housing (C) comprising a cylindrical shoulder portion (E) and a blind receiving portion (R) including a bottom wall (F), receiving the stator (S), the stator (S) being cylindrical with a base cooperating with the receiving portion (R), the stator (S) comprising central (TC) and peripheral (TP) straight laminations with reference to the axis of the cylindrical stator (S), the stator (S) being intended to be coaxial with the housing (C), the stator (S) being in a frame of reference in space comprising a longitudinal axis (X) along the central axis of the cylindrical stator (S) and a longitudinal direction of the laminations (TC, TP), a lateral axis (Y) perpendicular to the longitudinal axis (X), and a transverse axis (Z) perpendicular to the longitudinal axis (X) and to the lateral axis (Y),The shrink-fitting process comprises the following steps: - a machining step in which the receiving portion (R) of the housing (C) is machined to create a junction surface (J) with a rounded angle between the cylindrical shoulder portion (E) and the bottom wall (F); - a trimming step in which the length of the peripheral sheets (TP) along the longitudinal axis (X) is less than that of the central sheets (TC); and - a shrink-fitting step of the stator (S) in the housing (S) such that the sheets (TC, TP) bear against the shoulder portion (E), and the peripheral sheets (TP) are set at a distance from the bottom wall (F) of the housing (C).

2. A shrink-fitting method according to claim 1, characterized in that the joining surface (J) has a tangent radius between 0.5 mm and 10 mm.

3. Shrink-fitting method according to claim 2, characterized in that the joining surface (J) has a tangent radius of 0.7 mm.

4. Shrink-fitting method according to any one of claims 1 to 3, characterized in that the axis of the shoulder part (E) is parallel to the sheets (TC, TP).

5. Shrink-fitting method according to any one of claims 1 to 4, characterized in that the stator (S) comprises fewer peripheral laminations (TP) than central laminations (TC).

6. Motor vehicle stator (S) obtained by a shrink-fitting process according to any one of claims 1 to 5, the stator (S) being cylindrical and comprising central (TC) and peripheral (TP) straight laminations with reference to the axis of the cylindrical stator (S), characterized in that the laminations are notched so that the length of the peripheral laminations (TP) is less than that of the central laminations (TC); and in that the peripheral laminations are configured to present a distance from the bottom wall (F) of the housing (C).

7. A motor vehicle stator housing (C), obtained by a shrink-fitting process according to any one of claims 1 to 5, the housing (C) comprising a cylindrical shoulder portion (E) and a blind receiving portion (R) comprising a bottom wall (F), configured to receive a stator (S), characterized in that the housing (C) comprises a receiving portion (R) machined so as to produce a junction surface (J) with a rounded angle between the cylindrical shoulder portion (E) and the bottom wall (F).

8. Motor vehicle comprising a casing and a stator obtained by the shrink-fitting process according to any one of claims 1 to 5.

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