Rotating electric machine equipped with rolling bearing preloading means

Abstract

The invention relates mainly to an assembly for a rotating electrical machine, comprising: a support (22) having a recess (23) for a rolling bearing (24), a preloading member (32) intended to be arranged axially between an end wall of the recess (23) and the rolling bearing (24) for preloading the rolling bearing (24), and a retaining member (33) intended to be arranged radially between the rolling bearing (24) and a side wall of the recess (23) for retaining the rolling bearing (24), the retaining member (33) for retaining the rolling bearing (24) being arranged during the assembly phase of the rotating electrical machine so as to enable the preloading member (32) to be axially retained in the recess (23) of the support (22) before the rolling bearing (24) is inserted into the recess (23).

Description

Technical Field

[0001] The present invention relates to a rotating electric machine provided with a rolling bearing preloading member. The present invention is particularly advantageously, but not exclusively, applicable to a rotating electric machine equipped with a motor vehicle. Background Art

[0002] In a manner known per se, a rotating electrical machine has a stator and a rotor fixed to a shaft. The rotor can be fixed to a driving and / or driven shaft and can be a rotating electrical machine in the form of an alternator, an electric motor, or a reversible electrical machine capable of operating in two modes.

[0003] The rotor has a body formed by a stack of laminations held in the form of a group by a suitable fastening system such as rivets. The rotor has poles formed, for example, by permanent magnets housed in cavities provided in magnetic blocks of the rotor, as described, for example, in document EP 0803962. Alternatively, in a so-called "salient pole" architecture, the poles are formed by coils wound around the arms of the rotor.

[0004] Furthermore, the stator has a body formed by a stack of thin laminations forming a ring, the inner face of the body being provided with slots open towards the inside for receiving windings. The windings are obtained, for example, from a continuous wire covered with enamel, or from pins welded to each other. The windings may have a multiphase winding connected in star or triangle, the output of which is connected to an electronic control module having a power inverter that can operate in rectifier mode.

[0005] The stator is mounted in a housing with a bracket configured to rotatably support the shaft through rolling bearings. In order to optimize their service life, the rolling bearings of the rotary electric machine that guide the shaft in rotation must operate under axial and / or radial mechanical loads. For the electric machine constituting an alternator, the mechanical loads are applied through a belt motion transmission system inserted between a pulley on the front of the accessories of the combustion engine and a pulley mounted on the shaft of the electric machine.

[0006] However, for certain drive architectures comprising an electric motor engaged with a gear mechanism, in particular a gear mechanism of a gearbox, a number of life situations have been observed in which no torque is applied to the rotating electric machine, so that the rolling bearings are not under mechanical load.

[0007] Therefore, the applicant arranged the preload member in the rolling bearing recess.However, this created assembly problems in that all active components (rotor and stator) needed to be moved relative to the support in order to make the shaft and the corresponding rolling bearings of the support cooperate. Summary of the invention

[0008] The object of the present invention is to effectively remedy this drawback by proposing an assembly for a rotating electrical machine having:

[0009] a support having a recess for a rolling bearing,

[0010] a preloading member intended to be arranged axially between the end wall of the recess and the rolling bearing for preloading the rolling bearing, and

[0011] a retaining member intended to be arranged radially between the rolling bearing and the side wall of the recess for retaining the rolling bearing,

[0012] During the assembly phase of the rotating electrical machine, the retaining member for retaining the rolling bearing is arranged in such a way as to enable the preload member to be axially retained in the recess of the support before the rolling bearing is inserted into the recess.

[0013] The invention thus makes it easier to assemble the electric machine by allowing the assembly formed by the support, the retaining member for retaining the rolling bearing and the preloading member to be manipulated without the risk of the preloading member falling out during manipulation, while keeping the shaft immobile with its rolling bearings and the active parts (stator and rotor) during assembly of the support of the rotating electric machine.

[0014] According to one embodiment, the retaining member is arranged not to be in contact with the preloading member when the rolling bearing is inserted into the recess of the bracket.

[0015] According to one embodiment, the rolling bearing has an inner ring, an outer ring, and a seal disposed between the inner ring and the outer ring, and the preload member is configured to apply an axial force to the outer ring of the rolling bearing without contacting the seal. This makes it possible to extend the service life of the rolling bearing.

[0016] According to one embodiment, the preload member is a wave washer or a conical washer.

[0017] According to one embodiment, the retaining member is made of a material with a thermal expansion capacity greater than that of the rolling bearing in order to compensate for gaps between the rolling bearing and the support which may be generated during expansion of the support at high temperatures.

[0018] According to one embodiment, the holding member is made of a plastic material.

[0019] According to one embodiment, the retaining member has a body of annular shape, provided with axial retaining means for axially retaining said retaining member relative to the recess.

[0020] According to one embodiment, the retaining member consists of a tolerance ring.

[0021] According to one embodiment, the retaining member completely circumscribes the inner side of the recess without extending axially or radially beyond the end wall side of said recess.

[0022] The invention also relates to a rotating electrical machine having an assembly as defined above. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will be better understood by reading the following description and studying the accompanying drawings, which are given only by way of complete non-limiting illustration of the invention.

[0024] Figure 1 is a longitudinal sectional view of a rotating electric machine according to the present invention.

[0025] Figure 2 is a detailed cross-sectional view of a recess for a rolling bearing according to the present invention, in which a retaining member and a preload member for retaining the rolling bearing are arranged.

[0026] Figure 3 is a perspective view of a retaining member for retaining a rolling bearing according to the invention, the retaining member being intended to be integrated into a rotating electrical machine.

[0027] Figure 4 is a perspective view of a preloading member according to the invention for preloading a rolling bearing, which is intended to be integrated into a rotating electrical machine.

[0028] Figure 5 is a perspective view of a retaining member and a preloading member for retaining a rolling bearing according to the invention, which retaining member and preloading member are intended to be integrated into a rotating electrical machine. DETAILED DESCRIPTION

[0029] Identical, similar or like elements retain the same reference numerals in the various figures.

[0030] Figure 1 A rotating electrical machine 10 is shown having a multiphase stator 11 surrounding a rotor 12 mounted on a shaft 13 of axis X corresponding to the axis of the electrical machine 10. The stator 11 surrounds the rotor 12 with an air gap between the inner periphery of the stator 11 and the outer periphery of the rotor 12.

[0031] The rotor 12 has a body 15 in the form of a lamination stack in a manner known per se. Permanent magnets 16 are mounted in cavities of the body 15. Depending on the application of the electric machine 10 and the desired power, the permanent magnets 16 can be made of rare earth or ferrite.

[0032] Furthermore, the stator 11 has a body 18 and a winding 19. The body 18 has a plurality of slots with axial and radial openings for mounting the stator winding 19. In this case, the winding 19 is formed by pins welded to each other. As a variant, the winding can be formed by a continuous wire covered with enamel or by a coil wound around the teeth of the body 18. The winding 19 can have a multi-phase winding connected in star or triangle, the output of which is connected to an electronic control module having a power inverter that can operate in rectifier mode.

[0033] The motor 10 also has a front bracket 21 and a rear bracket 22, which are made of, for example, an aluminum-based material. The front bracket 21 and the rear bracket 22 are each provided with a recess 23 intended to receive a rolling bearing 24, in particular a ball bearing, which guides the shaft 13 in rotation.

[0034] The rolling bearing 24 has an inner ring 24.1, an outer ring 24.2, balls 24.3 that allow relative rotational movement between the two rings 24.1, 24.2, and a seal 24.4 disposed between the inner ring 24.1 and the outer ring 24.2.

[0035] The front bracket 21 is located on the output side of the shaft 13 intended to cooperate with external elements of the motor 10 , such as a gear mechanism of a gearbox, while the rear bracket 22 is located on the opposite side of the output relative to the shaft 13 .

[0036] In this case, the supports 21 , 22 have a wall 26 oriented transversely to the axis X, comprising a centrally located recess 23 for the rolling bearing 24 , and remote from this wall by an annular side wall 27 oriented axially to the axis X.

[0037] The cooling chamber 29 is defined by the outer periphery of the side wall 27 of the front bracket 21 and the inner periphery of the side wall 27 of the rear bracket 22. This cooling chamber 29 is hermetically closed at the axial ends by two seals 30. The stator 11 is preferably installed in the front bracket 21 in an interference fit manner so that a close contact is established between the outer periphery of the body of the stator 11 and the inner periphery of the side wall 27 of the front bracket 21.

[0038] like Figure 2 As shown, in order to ensure the operation of the rolling bearing 24 under mechanical load, the preload member 32 is axially arranged between the end wall of the recess 23 of the rear bracket 22 and the corresponding rolling bearing 24, so as to apply an axial force to the rolling bearing 24. In addition, the retaining member 33 for retaining the rolling bearing 24 is radially arranged between the rolling bearing 24 and the side wall of the recess 23.

[0039] During the assembly phase of the rotary electric machine 10, the retaining member 33 is arranged so that the preload member 32 can be axially retained in the recess 23 of the rear bracket 22 before the rolling bearing 24 is inserted into the recess 23. To this end, the outer diameter D1 of the preload member 32 is greater than the inner diameter D2 of the retaining member 33 and is smaller than or equal to the outer diameter D3 of the retaining member 33. The outer diameter D3 of the retaining member 33 is substantially equal to the inner diameter of the recess 23.

[0040] Thus, when the assembly “bracket 22 , preloading member 32 and retaining member 33 ” is placed vertically, the preloading member 32 may rest on an axial end of the retaining member 33 to cooperate with the rolling bearing 24 of the shaft 13 on which the rotor 12 is mounted.

[0041] The preload member 32 is configured to apply an axial force to the outer ring 24.2 of the rolling bearing 24 without contacting the seal 24.4. This makes it possible to extend the service life of the rolling bearing 24. The preload member 32 is preferably a wave washer, such as Figure 2 , Figure 4 and Figure 5 Thus, the washer 32 has a plurality of undulations 35 formed continuously by crests 36 and troughs 37. Depending on the application, in particular on the forces to be applied to the rolling bearing 24, the number of undulations 35 of the washer 32 is, for example, between 3 and 8. Alternatively, the washer 32 may be a conical washer.

[0042] Advantageously, the retaining member 33 is arranged so as not to contact the preload member 32 when the rolling bearing 24 is inserted into the recess 23 of the support. To this end, the axial length L1 of the retaining member 33 is smaller than the axial length L2 of the outer ring 24.2 of the rolling bearing 24, as shown in FIG. Figure 2 shown.

[0043] The retaining member 33 is made of a material, in particular a plastic material, the thermal expansion of which is greater than that of the rolling bearing 24 in order to compensate for the play between the rolling bearing 24 and the support 22 which may occur during expansion of the support 22 at high temperatures.

[0044] In this case, if Figure 3 and Figure 5 As shown in FIG. 1 , the retaining member 33 has a body 33.1 of annular shape, provided with axial retaining means 33.2 for axially retaining the retaining member 33 relative to the recess 23. The axial retaining means 33.2 may consist, for example, of a lip intended to be inserted into a correspondingly shaped groove 39 provided in the recess 23 (see FIG. 1 ). Figure 2 ).

[0045] The retaining member 33 may also have an anti-rotation means 33.3 consisting of a lug which is inserted in a correspondingly shaped recess provided in the recess 23. However, the presence of the anti-rotation means 33.3 is not essential.

[0046] The retaining member 33 completely circumscribes the inner side of the recess 23 without extending axially or radially beyond the end wall side of the recess 23 .

[0047] As a variant, the retaining member 33 is composed of a tolerance ring. This tolerance ring has an elastically deformable annular portion to adapt to the dimensional changes of the recess 23 during its expansion and a plurality of elements mounted on the inner periphery of the annular portion. These internal elements are also elastically deformable to ensure contact with the rolling bearing 24.

[0048] Of course, the above description is given by way of example only and does not limit the scope of the present invention; replacing various elements with any other equivalents will not constitute a departure from the scope.

[0049] Furthermore, various features, variations and / or embodiments of the present invention may be combined with one another in various combinations as long as they are compatible or not mutually exclusive.

Claims

1. A component for a rotating electrical machine (10), characterized in that The components have: a support (22) having a recess (23) for a rolling bearing (24), a preloading member (32) intended to be arranged axially between the end wall of the recess (23) and the rolling bearing (24) for preloading the rolling bearing (24), and a retaining member (33) intended to be arranged radially between the rolling bearing (24) and the side wall of the recess (23) for retaining the rolling bearing (24), During the assembly phase of the rotating electrical machine (10), the retaining member (33) for retaining the rolling bearing (24) is arranged to enable the preload member (32) to be axially retained in the recess (23) of the support (22) before the rolling bearing (24) is inserted into the recess (23); The retaining member (33) is arranged so that the outer side of the rolling bearing (24) does not contact the inner side of the recess (23).

2. The assembly according to claim 1, characterized in that The retaining member (33) is arranged not to contact the preload member (32) when the rolling bearing (24) is inserted into the recess (23) of the bracket (22).

3. The assembly according to claim 2, characterized in that The rolling bearing (24) has an inner ring (24.1), an outer ring (24.2), and a seal (24.4) arranged between the inner ring (24.1) and the outer ring (24.2), and the preload member (32) is configured to apply an axial force to the outer ring (24.2) of the rolling bearing (24) without contacting the seal (24.4).

4. The assembly according to any one of claims 1 to 3, characterized in that The preload member (32) is a wave washer or a conical washer.

5. The assembly according to any one of claims 1 to 4, characterized in that The retaining member (33) is made of a material having a thermal expansion capacity greater than that of the rolling bearing (24) so ​​as to compensate for a gap between the rolling bearing (24) and the bracket (22), the gap being generated during the expansion of the bracket (22) at high temperature.

6. The assembly according to claim 5, characterized in that The holding member (33) is made of plastic material.

7. The assembly according to any one of claims 1 to 6, characterized in that The retaining member (33) has a body (33.1) in an annular shape and is provided with an axial retaining device (33.2) for axially retaining the retaining member (33) relative to the recess (23).

8. The assembly according to any one of claims 1 to 6, characterized in that The retaining member (33) consists of a tolerance ring.

9. The assembly according to any one of claims 1 to 8, characterized in that The retaining member (33) completely circumscribes the inner side of the recess (23) without extending axially or radially beyond the end wall side of the recess (23).

10. A rotating electrical machine (10) having an assembly as defined in any one of the preceding claims.

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