Method of manufacturing and fitting a ball bearing around a rotating shaft by shrink fitting.

Abstract

Method for manufacturing and shrink-fitting a ball bearing around a rotating shaft. The method comprises an operation (OP1) of nominal manufacturing of the ball bearing (5) and the rotating shaft (3). Then, a modeling operation (MD) of identifying (OP2) a deformed raceway (P2) of the nominal raceway (P1) of the ball against its inner ring (6b) by a specified shrink-fitting force of the inner ring (6b) around the rotating shaft (3), and of identifying (OP3) a corrected raceway (P3) of the ball against the inner ring (6b) by correcting the shape of said nominal raceway (P1) subsequently carried out (OP4) in accordance with obtaining a restoration of said nominal raceway (P1) in the shrink-fitting station of the ball bearing (5) around the rotating shaft (3). [Fig. 4]

Description

Title of the invention: Method for manufacturing and mounting by shrink fitting a ball bearing around a rotating shaft. Technical field of the invention

[0001] The invention relates to the field of ball bearings or, by analogy, roller or needle bearings, for example. More specifically, the invention relates to the manufacturing methods of at least one component of a structural assembly comprising a rotating shaft and a ball bearing, and, as a corollary, to the methods of mounting the ball bearing by shrink-fitting around the rotating shaft. Prior art

[0002] Among the methods for mounting a ball bearing around a rotating shaft, it is known to perform such mounting by shrink-fitting the ball bearing around the rotating shaft. Such a mounting operation is based on the ball bearing clamping the rotating shaft under stress. Typically, in the ball bearing mounting station around the rotating shaft, the ball bearing and the rotating shaft are coaxial, extending axially along a common axis.

[0003] To clarify the context of the invention and the vocabulary commonly used in this field, a ball bearing comprises a cage formed between a coaxial inner ring and outer ring. The inner and outer rings house at least one set of balls arranged around a circumference centered on the axis of extension of the ball bearing. A nominal clearance for the balls is provided within the cage, between the balls on one side and the inner and outer rings on the other. A single ball bearing can be equipped with several sets of balls distributed axially at a distance from each other within the cage. Several ball bearings can be mounted around the rotating shaft at an axial distance from each other.

[0004] The terms "inner" and "outer" are relative to the axis of extension of the ball bearing and / or the axis of rotation of the shaft around which the ball bearing is coaxially mounted. The term "inner" commonly refers to a position close to these axes, as opposed to the term "outer," which refers to a position further from these axes.

[0005] According to a shrink-fitting assembly of at least one ball bearing around the rotating shaft, the ball bearing is positioned axially around the rotating shaft, which it surrounds diametrically. Such a tight fit prevents the ball bearing from being mounted around the rotating shaft by hand or with a press. It is therefore common practice to heat the inner ring of the ball bearing to expand it prior to installation. ball bearing around the rotating shaft, and / or conversely potentially to cool the rotating shaft.

[0006] Generally speaking, it is known that shrink-fitting the inner ring of a ball bearing around a rotating shaft tends to cause deformation of the rotating shaft, which is then subjected to diametral stresses. See, for example, document EP4147817 (NTN-SNR BEARINGS) for further details.

[0007] According to this document, a ball bearing is shrink-fitted around a hub having an inner bore with splines, through which the hub can be coupled to a drive shaft. To prevent permanent damage to the splines after shrink-fitting, the rotating shaft has plain bearings at its ends, between which the inner ring of a ball bearing is axially positioned. Prior to shrink-fitting, one of the plain bearings is deformed by bending using a wedge forced into the bore, so that after shrink-fitting, the deformed plain bearing returns to its original shape under the stresses it is subjected to.

[0008] In the field of structural assemblies comprising several components assembled together, a persistent difficulty to overcome is the search for a reduction in their size, particularly in the presence of rotating parts whose axial extension can generate overhangs.

[0009] More specifically, consideration is given to the usual case where a structural assembly comprises several components, including at least one rotating shaft equipped with a ball bearing mounted around the rotating shaft by shrink fitting via the inner ring of the ball bearing, the rotating shaft being intended to be axially coupled with another rotating component. To clarify the concept of a rotating component, it can be arranged in various ways, such as, for example, as a drive shaft for rotating the rotating shaft or, conversely, as a driven shaft driven by the rotating shaft.

[0010] In this context, a common solution is to couple the rotating shaft to said rotating component via splines of complementary shapes as described in the previously mentioned document EP4147817. Another common solution is to couple the rotating shaft to said rotating component by keying, the rotating shaft having for this purpose at least one axial groove formed in the mass of the rotating shaft at its periphery, it being understood, but if necessary specified, that the axial groove is typically open at the periphery of the rotating shaft.

[0011] However, it is noted here that such solutions unnecessarily imply a significant diametral and / or axial increase in the structural assembly of components. More precisely, either the ball bearing(s) is / are mounted around the splined or grooved keyway of the rotating shaft – which necessitates a significant increase in the radial thickness of the inner ring of the ball bearing(s) mounted around the rotating shaft – or the ball bearing(s) are axially offset from the splined or grooved keyway of the rotating shaft.

[0012] Otherwise, if the ball bearing is mounted around the rotating shaft in its splined or grooved area, at least one indentation will form on the ball raceway against the inner ring and / or potentially an overall deformation of said raceway. This is due to the presence of the recesses formed between the splines or by said at least one groove.

[0013] It follows that during the rotation of the rotating shaft, such indentations or overall deformation of the raceway induce a risk of the balls rolling against the inner ring becoming stuck in rotation, and / or of causing vibrations by resonance which may be significant and detrimental to obtaining proper rotation of the rotating shaft, and / or of affecting the durability of the ball bearing and / or the rotating shaft. Presentation of the invention

[0014] In this context, and generally according to a concise presentation of the invention, the invention relates to a method for manufacturing the components of a structural assembly, comprising at least one rotating shaft having at least one axial groove on its periphery, and at least one ball bearing. This manufacturing method is correlated with a method for shrink-fitting the ball bearing(s) around the rotating shaft in its axial region, which includes said at least one groove that provides a coupling interface between the rotating shaft and a rotating component of said structural assembly.

[0015] Conventionally, to clarify if necessary, it is understood that said at least one groove is, for example, a keyway between the rotating shaft and the rotating component, or, for example, at least one groove formed by a splined arrangement of the rotating shaft. Said at least one groove extends axially around the periphery of the rotating shaft parallel to its axis of extension, presenting an opening to the outside of the rotating shaft at its periphery.

[0016] The groove is formed in the peripheral mass of the rotating shaft, extending to a specified depth in the direction of its axis of rotation and to a specified width along the periphery of the rotating shaft. According to various possible alternative configurations of said at least one groove, the groove extends axially, in whole or in part, to the periphery of the rotating shaft. In other words, the groove is capable of extending axially over the entire axial extent of the rotating shaft, or partially, presenting a blind bottom along its axial extent. at least one of its axial extremities.

[0017] Based on the observation previously stated and which relates to the approach taken in developing the invention, the invention aims to solve the problem posed - and to overcome the difficulties that result from it - of a shrink-fitting assembly of at least one ball bearing around a rotating shaft having at its periphery at least one axial groove extending around the periphery of the rotating shaft.

[0018] More specifically, the invention proposes to address the potential formation of an alteration in the ball bearing raceway, which is formed on the outer periphery of the inner ring, and / or at least one indentation that forms locally on said raceway, causing its localized alteration. Such alterations of the ball raceway against the inner ring of the ball bearing result from the presence of said at least one groove, which has an opening oriented outwards towards the rotating shaft at its periphery, and from the shrink-fitting of said inner ring around the rotating shaft that it encloses.

[0019] To achieve this, initial manufacturing operations for the ball bearing and the rotating shaft are conventionally carried out according to nominal characteristics that identify their structure, arrangement, and / or conformation in the rest state. In the context of the invention, the respective structures of the ball bearing and the rotating shaft, defined by their nominal characteristics, are sought to be maintained after the ball bearing is shrink-fitted around the rotating shaft.

[0020] Prior to mounting the ball bearing around the rotating shaft, the manufacturing process includes a modeling operation to determine the deformation of the ball raceway against the inner ring of the ball bearing, taking into account, in particular, the presence of at least one groove. Then – based on the identified deformation of said raceway – the modeling process continues to determine, by modeling, a form correction of the nominal conformation(s) of the ball bearing and / or the rotating shaft, at least with regard to the ball raceway against the inner ring of the ball bearing.

[0021] Such shape corrections are identified during the modeling operation and then made - preferably by machining - so that at least the appropriate nominal conformation of the ball race against the inner ring of the ball bearing is obtained after shrink-fitting the inner ring of the ball bearing around the rotating shaft.

[0022] In other words, such form corrections are identified from said modeling so that after the shrink-fitting of the ball bearing around the rotating shaft, the ball bearing - in particular the inner ring it comprises and / or The rotating shaft - regain their nominal conformation, or in other words, their conformation before their form correction. Said form corrections are identified and then carried out based on said modeling, so that in particular a nominal clearance of the ball bearing setpoint inside the cage of the ball bearing that houses them is maintained notwithstanding the shrink-fit mounting of the ball bearing around the rotating shaft and the presence of said at least one groove that the rotating shaft has.

[0023] Said modeling, identifying on the one hand the deformation of the ball raceway against the inner ring and on the other hand the form corrections of the inner ring and / or the rotating shaft from the previously obtained identification of the raceway deformation, is carried out by taking into account in particular the following calculation factors: a) for identifying the deformation of the ball bearing raceway against the inner ring - in combination at least two by two - at least: -) the width of said at least one groove that the rotating shaft has, -) the thickness of the inner ring - or in other words the radial extension of the inner ring of the ball bearing around the shaft rotating along its outer periphery - which is preferably sought to be as small as possible, -) the material of the inner ring, and more specifically at least its characteristics of reversible plasticity under stress, and -) the clamping force of the rotating shaft by the inner ring shrink-fitted around the rotating shaft to a desired clamping force threshold - without being excessive - providing a firm hold of the ball bearing around the rotating shaft. b) then for the identification of the form corrections to be made to the inner ring of the ball bearing and / or the rotating shaft, at least in combination: -) the previously identified deformed raceway conformation, and -) a nominal clearance setting for the ball bearings within the ball bearing cage. As a reminder, the cage is typically located between the outer and inner rings of the ball bearing.

[0024] Said form corrections of the inner ring and / or the rotating shaft are preferably made by machining to perfect the accuracy of the form corrections of the inner ring and / or the rotating shaft to be applied in accordance with their prior identifications by modeling.

[0025] It is nevertheless understood that the less advantageous use of other techniques for carrying out the form corrections to be performed cannot be excluded, such as, for example, reversible plastic deformation under stress of the inner ring and / or the rotating shaft, or any other technique(s) suitable for materially correcting the nominal characteristics of a mechanical part, particularly in the context of the invention the conformation of the inner ring and / or the rotating shaft after the identification of the corrections to be made which are precisely obtained advantageously by modeling.

[0026] Corrections to the shape of the inner ring and / or the rotating shaft can, for example, be corrections to their overall conformation. For further examples: -) The form correction of the inner ring can be a form correction of its internal bore, either global or limited to the ball bearing race against the inner ring. -) The form correction of the rotating shaft can, for example, still be either limited to its perimeter - or in other words to its outer peripheral face - or still be limited to the conformation of the groove, in particular with regard to the extension in width of the opening of the groove intended to be oriented towards the inner ring of the ball bearing after the shrink-fit assembly of the ball bearing around the rotating shaft.

[0027] An indexing system for identifying the relative angular positioning of the rotating shaft with respect to the rotating component to which it is coupled is advantageously used to also angularly position the inner ring of the ball bearing after correction of its shape, taking into account in particular the location of the indentation or indentations that may form on the ball bearing raceway as a result of the shrink-fitting of the inner ring of the ball bearing around the rotating shaft.

[0028] An advantageous application of the invention is adapted to the rotary assembly between the rotating shaft and a connecting element comprising a rotor of an electric machine for driving the rotating shaft, and / or between the rotating shaft and a driven shaft rotated by the rotating shaft.

[0029] For this purpose, according to a preferred embodiment, at least one pair of diametrically opposed grooves are provided on the periphery of the rotating shaft, for keying assembly between the rotating shaft and the rotor of the electric machine and / or between the rotating shaft and the driven shaft, promoting the rotational drive and balancing of the rotation of the rotating shaft by the rotor and / or of the driven shaft by the rotating shaft.

[0030] The internal volume of the groove(s) being closed by the inner ring of the ball bearing shrink-fitted around the rotating shaft, the radial and axial junction between the rotating shaft and the junction member equipping the rotor and / or the radial and axial junction between the rotating shaft and the receiving shaft are obtained as robust, efficient and durable.

[0031] In view of the foregoing, the invention relates to a method for manufacturing the components of a structural assembly of components. The structural assembly of components comprises at least one ball bearing and at least one shaft a rotating part provided at its periphery with at least one axial groove having an opening at the periphery of the rotating shaft. The groove provides a coupling interface between the rotating shaft and at least one rotating component comprising said structural assembly of components.

[0032] The ball bearing typically comprises an outer ring and a coaxial inner ring, which together provide a cage housing at least one set of balls distributed along a circumference centered on an extension axis of the ball bearing.

[0033] At least one inner ring of the ball bearing provides at least one raceway for the balls to roll against the outer face of the inner ring of the ball bearing. A nominal bearing clearance is provided between the balls and the cage of the ball bearing that houses them. It is understood, but specified if necessary, that said nominal bearing clearance is provided between, on the one hand, the balls, and on the other hand, the inner and outer rings of the ball bearing.

[0034] The manufacturing process is correlated with a coaxial shrink-fit mounting method for the ball bearing around the rotating shaft in its axial region comprising at least one groove, the opening of which is oriented towards the inner ring. The inner ring radially closes the opening of the groove by confining the internal volume of at least one groove, which is included, but if necessary specified, within its axial region enclosed by the inner ring.

[0035] The manufacturing process includes an initial operation of manufacturing the ball bearing according to nominal characteristics and manufacturing the rotating shaft according to nominal characteristics in accordance with an axially fitted fitting of the rotating shaft inside the inner ring.

[0036] In this context, the invention is recognizable in that prior to the shrink-fitting of the ball bearing around the rotating shaft at least in its area having said at least one groove, the manufacturing process includes a determination operation by modeling: -) in a first modeling step, of an identification of a deformed track of the nominal ball bearing track against the inner ring caused by a clamping force of the rotating shaft by the inner ring shrink-fitted around the rotating shaft and / or by the presence of said at least one groove, then -) in a second modeling step taking into account the identification of the previously determined deformed track, an identification of a corrected track for the rolling of the balls against the inner ring by correcting the shape of at least the nominal track for the rolling of the balls against the inner ring in accordance with obtaining a restoration of the nominal rolling track in the shrink-fit station of the ball bearing around the rotating shaft.

[0037] Other specific features of the invention - not restrictive or limiting with regard to other features it may have - are as follows.

[0038] By way of non-restrictive indication, the identification by modeling of the deformation of said deformed track takes into account at least the following calculation factors according to at least any combination of them in at least two by two: -) the width of the opening of said at least one groove that the rotating shaft comprises, -) the thickness of the inner ring is advantageously sought, preferably as small as possible, -) the material of the inner ring, identifying at least its characteristics of reversible plasticity under stress, -) the material of the rotating shaft, identifying at least its characteristics of reversible plasticity under stress, and -) the clamping force of the rotating shaft by the inner ring shrink-fitted around the rotating shaft to a predefined clamping force threshold, without being excessive, capable of providing firm support of the ball bearing around the rotating shaft.

[0039] By way of non-restrictive indication, the identification of the corrected raceway takes into account at least the calculation factor relating to the deformed raceway and a calculation factor relating to the nominal rolling clearance between the balls and the cage of the ball bearing that houses them. It is understood, but specified if necessary, that said nominal rolling clearance is provided between, on the one hand, the balls and, on the other hand, the inner and outer rings of the ball bearing.

[0040] The form correction of at least the nominal ball bearing race against the inner ring is in particular carried out in accordance with the previously identified corrected race, by correcting the form of at least one of the inner ring of the ball bearing and / or the rotating shaft.

[0041] The form correction of the inner ring of the ball bearing is, for example, an overall form correction of the inner bore of said inner ring of the ball bearing. It is not excluded to correct the overall form of the inner ring, or to correct the overall form of not only the inner ring but also the outer ring.

[0042] The form correction of the inner ring of the ball bearing is, for example, yet another form correction of the inner bore of the inner ring of the ball bearing, which is limited to the extension of the nominal ball bearing race against the inner ring.

[0043] The shape correction of the rotating shaft is, for example, a global shape correction of the conformation of the rotating shaft.

[0044] The form correction of the rotating shaft is, for example, yet another correction of form limited to the outlet of said at least one groove which comprises the rotating shaft.

[0045] The form correction of at least one of the inner ring of the ball bearing and / or the rotating shaft is more specifically preferably carried out by machining.

[0046] By way of a non-restrictive example of an application of the invention to said structural assembly of components to be assembled together, said structural assembly of components comprises an electrical machine combining a stator and a rotor. The rotor includes a junction element connecting the rotor to the rotating shaft. The volume of the junction element is calibrated according to a nominal volume at least equivalent to the internal volume of said at least one groove, the opening of which is closed by the inner ring.

[0047] In other words, the manufacturing of the connecting element to its nominal volume is correlated with the manufacturing of the rotating shaft and more specifically with the operation of forming said at least one groove made on the periphery of the rotating shaft. In the assembly station of said connecting element with the rotating shaft, said connecting element is at least confined, if not clamped, inside said at least one groove, being firmly held between the rotating shaft and the inner ring of the ball bearing mounted by shrink fitting around the rotating shaft. Presentation of the figures

[0048] The invention will be better understood upon reading the following detailed description of an exemplary embodiment, in relation to the following figures: [Fig. 1] is an example illustrating an application of the present invention to a partially shown electrical machine. According to this example, the structural assembly of components includes the electrical machine, which combines a stator and a rotor for driving a rotating shaft. For its rotational drive, the rotating shaft is connected to the rotor by a connecting element housed within peripheral axial grooves in the rotating shaft, each groove having an opening oriented towards a ball bearing shrink-fitted around the rotating shaft. [Fig.2] is a representation of the shrink-fitted ball bearing around the rotating shaft that comprises the structural assembly of components illustrated in [Fig.1]. [Fig. 3] is a diagram illustrating the problem to be solved by the invention and schematically the methods of its solution. In [Fig. 3], the diagram illustrates the diametrical profile of a ball raceway against an inner ring of the ball bearing shown in [Fig. 2], according to three different schematic conformations. represented specifically for educational purposes. [Fig. 4] is a flowchart illustrating methods for determining, by modeling, a change in the shape of the track profile with reference to the different conformations of the track profile shown schematically in [Fig. 3]. Detailed description of the invention

[0049] The figures and their detailed, non-limiting descriptions set forth the invention in particular ways that are not restrictive as to the scope of the invention. The figures and their detailed descriptions of an example of an embodiment of the invention may serve to better define it, if necessary in relation to the general description just given. Furthermore, to avoid cluttering the figures and thus facilitate their reading, the reference numbers assigned to the terms and / or concepts used to describe the invention and indicated on any one of the figures may be repeated in the description of any other figure without implying their presence on all the figures.

[0050] Figure 1 shows, by way of example, a structural assembly 1 of components comprising an electric machine 2 conventionally employing a stator 2a and a rotor 2b cooperating with each other. The rotor 2b is rotationally linked to a rotating shaft 3 for its rotational drive by the rotor 2b, via a connecting element 4 in the rotor 2b. The rotating shaft 3 is equipped with at least one ball bearing 5a, only one ball 5a being referenced to avoid increasing the weight of Figure 1. The ball bearing 5a is mounted coaxially A1 by shrink fitting around the rotating shaft 3. As a result of their coaxial mounting A1, the axis of the ball bearing 5a and the axis of the rotating shaft 3 are identified by the same reference A1 to simplify the reading of the figures and facilitate the description and / or understanding of the invention.

[0051] To clarify, if necessary, the notion of structural assembly 1 of components introduced to define the invention, the components of said structural assembly 1 compose a functional structure by cooperating with each other at least two by two.

[0052] In the context of the invention, said components at least comprise a rotating shaft 3 and at least one ball bearing 5a. The components of the ball bearing 5a, which are part of said structural assembly 1 of components, typically comprise an outer ring 6a and an inner ring 6b radially forming between them a cage 6 housing at least one set of balls 5a distributed along a circumference CL

[0053] As more clearly seen in [Fig. 2], bearing tracks 7a, 7b for the balls 5a are provided respectively on the inner face of the outer ring 6a and on the outer face of the inner ring 6b. A nominal clearance J1 for the bearing of the balls 5a inside the cage 6 - according to the circumference Cl of their distribution within the cage 6 - is provided inside cage 6 between the balls 5a on one side and on the other side between the outer ring 6a and the inner ring 6b of the ball bearing 5 6a.

[0054] According to the application example of the invention to an electrical machine 2 illustrated in [Fig. 1], the structural assembly 1 of components comprises in this case the components of the electrical machine 2, in particular the stator 2a and the rotor 2b. The rotor 2b includes a component forming said axial and rotating connecting element 4 between the rotor 2b and the rotating shaft 3 for its rotational drive by the rotor 2b.

[0055] In [Fig. 1] and more clearly in [Fig. 2], the ball bearing 5a is shrink-fitted around the rotating shaft 3. For the assembly between the rotating shaft 3 and the rotor 2b, the rotating shaft 3 has at least one groove 8 on its periphery for receiving the connecting member 4 of the rotor 2b. According to the illustrated example, the rotating shaft 3 preferably has a pair of diametrically opposed grooves 8 on its periphery. Each of the grooves 8 has an opening 8a on the periphery of the rotating shaft 3 for the inner ring 6b shrink-fitted around the rotating shaft 3.

[0056] Referring to [Fig.3], the problem posed and the basis of the invention stem from the observation that, as a result of the shrink-fitting of the ball bearing 5a around the rotating shaft 3 via the inner ring 6b of the ball bearing 5a, the nominal race PI of the ball bearing 5a against the inner ring 6b deforms under the effect of the diametral stress supported by the inner ring 6b and by the presence of the grooves 8 that comprise the rotating shaft 3.

[0057] The deformation of said nominal raceway PI of ball bearing 5a against the inner ring 6b can be global and / or be localized by the formation of indentations 9 on said nominal raceway PI of ball bearing 5a.

[0058] Such deformations of the nominal raceway PI of the ball bearing 5a are formed under the effect of the clamping of the rotating shaft 3 by the inner ring 6b, which is then subjected to diametral stresses. The formation of the indentations 9 is more specifically caused by the presence of the grooves 8 providing cavities open towards the inner face of the inner ring 6b of the ball bearing 5a.

[0059] It is therefore noted, in particular, that there is a risk of the balls 5a rolling inside the cage 6 that houses them becoming stuck in rotation, as the deformation of the inner ring 6b can completely or partially eliminate the nominal clearance J1 of the balls 5a between the balls 5a and the rings 6a, 6b that make up the ball bearing 5. It is also noted, in particular, that the deformation of the nominal raceway PI of the balls 5a against the inner ring 6b causes, as a result of the balls 5a rolling against the inner ring 6b, vibrations that can be significant and detrimental to achieving balanced rotation of the rotating shaft 3.

[0060] To overcome such drawbacks, the invention proposes a manufacturing process for components of said structural assembly 1 of components, in particular with regard to the ball bearing 5a and / or the rotating shaft 3. To clarify and facilitate the understanding of the description of the invention, the description of said manufacturing process is correlated with the technique of shrink-fitting the ball bearing 5a around the rotating shaft 3 and the methods of joining the rotating shaft 3 with a drive shaft rotating the rotating shaft 3 and / or a driven shaft rotating by the rotating shaft 3 according to various applications of the invention to specific structural assemblies of components.

[0061] In [Fig.3], three conformations of a ball raceway 5a against the inner ring 6b of the ball bearing 5a are illustrated in the same figure. It is specified, but clearly understood, that the three raceways shown are illustrative, without prejudice to their actual conformations, which depend on the specific applications of the invention and / or the result of their identification by modeling as described later in relation to [Fig.4].

[0062] The three raceways of the balls 5a against the inner ring 6b of the ball bearing 5a illustrated in [Fig.3] are as follows: -) a first raceway is the nominal raceway PI of the raceway obtained according to the initial manufacturing nominal characteristics of the 5-ball bearing 5a, hereafter referred to as the nominal 5-ball bearing 5a; -) a second raceway is a deformed raceway P2, resulting from the shrink-fitting of the nominal ball bearing 5a around the rotating shaft 3, which causes - as previously referred to - a deformation of the nominal raceway PI under the effect of the clamping stresses of the rotating shaft 3 by the inner ring 6b of the ball bearing 5a; -) a third raceway is a corrected raceway P3 of the nominal raceway PI prior to shrink-fitting the ball bearing 5a around the rotating shaft 3, it being understood that the ball bearing 5a shrink-fitted around the rotating shaft 3 is the ball bearing 5a having the corrected raceway P3.

[0063] As a reminder concerning the deformed raceway P2 of the bearing, the deformation of the nominal raceway PI of the bearing into the deformed raceway P2 of the bearing results from the shrink-fitting of the nominal ball bearing 5a causing the global deformation - and / or the formation of localized indentations 9 - of the nominal raceway PI of the bearing into the deformed raceway P2 of the bearing.

[0064] In order that – as a result of the shrink-fitting of the ball bearing 5a around the rotating shaft 3 ([Fig. 4]) – the raceway 7b of the balls 5a against the inner ring 6b conforms to the nominal raceway PI of the bearing, the invention proposes to correct the conformation of the nominal raceway PI of the bearing into a said corrected race P3 of bearing taking the conformation of the nominal race PI of bearing after mounting by shrink fitting OF1 of the ball bearing 5 5a around the rotating shaft 3.

[0065] To this end, with reference to [Fig. 3] and [Fig. 4], the invention proposes a method for manufacturing a ball bearing 5a and / or the rotating shaft 3 around which the ball bearing 5a is intended to be shrink-fitted. This manufacturing method comprises the following operations: -) to manufacture OP1 conventionally the ball bearing 5a in accordance with its nominal characteristics C5 - and therefore including in particular the said nominal race PI of the ball bearing 5a and the nominal clearance J1 of the ball bearing 5a inside the cage 6 formed between the upper and lower rings of the ball bearing 5a - and to manufacture OP1 the rotating shaft 3 in accordance with its nominal characteristics C3, in particular with regard to the nominal characteristics of the grooves 8 and more specifically the width L1 of the opening 8a of the grooves 8 oriented towards the inner ring 6b of the ball bearing 5a, then -) correct OP4 based on the identification of said deformed raceway P2 of the balls 5a against the inner ring 6b of the ball bearing 5a, and the raceway 7b of the balls 5a against the inner ring 6b of the ball bearing 5a.

[0066] As a result of the correction of said nominal raceway PI, the raceway 7b of the balls 5a of the ball bearing 5a, mounted by shrink fitting OF1 around the rotating shaft 3, regains, by deformation of the inner ring 6b of the ball bearing 5a, its nominal characteristics in accordance with the nominal raceway PI, and the nominal clearance J1 of the balls 5a within the cage 6 that houses them is maintained. Thus, when the rotating shaft 3 is started, the risk of the balls 5a rolling within the cage 6 that houses them is avoided, and the generation of vibrations is prevented.

[0067] In [Fig. 4] more specifically, the manufacturing process of the 5-ball bearing 5a and / or of the rotating shaft 3 includes the following successive operations: -) an OP1 operation to manufacture the nominal ball bearing 5a according to its nominal characteristics C5 and to manufacture the nominal rotating shaft 3 according to its nominal characteristics C3, then -) by MD modeling, an OP2 operation to determine the deformed raceway P2 of the bearing, then an OP3 operation to determine a shape correction CFI of the nominal ball bearing 5a and / or a shape correction CF2 of the nominal rotating shaft 3, then -) a machining operation OP4 of the inner ring 6b and / or the nominal rotating shaft 3 giving them respective mounting characteristics CM5, CM3 according to which the bearing race 7b of the balls 5a against the inner ring 6b is conforming to the nominal PI bearing race after the OF1 shrink-fitting operation of the 5 ball bearing 5a around the rotating shaft 3.

[0068] The modeling determination of the deformation of the ball raceway 7b against the inner ring 6b takes into account at least the following calculation factors. It is further specified here, if necessary, that these calculation factors are provided for illustrative purposes only and are not restrictive, being taken into account in at least one combination of them, in pairs or otherwise, depending on the application and / or context in which the invention is used, is relevant, or is used.

[0069] Regarding the determination OP2 by modeling of said deformed running track P2, for example, the following is taken into account: -) the width L1 of the opening 8a of said at least one groove 8 which comprises the rotating shaft 3, -) the desired thickness El of the inner ring 6b to be as small as possible, -) the MAI material of the inner ring 6b of the ball bearing 5a, identifying at least its characteristics of reversible plasticity under stress, -) the MA2 material of the rotating shaft 3, identifying at least its characteristics of reversible plasticity under stress, and -) the clamping force EF1 of the rotating shaft 3 by the inner ring 6b shrink-fitted around the rotating shaft 3 to a desired clamping force threshold, without being excessive, providing a firm hold of the ball bearing 5a around the rotating shaft 3.

[0070] Regarding the determination OP3 by modeling of the corrected raceway P3 of the bearing - or in other words, more generally the shape correction of the raceway 7b of the balls 5a against the outer face of the inner ring 6b - at least the following are taken into account in combination: -) the calculation factor relating to the previously identified deformed P2 running track, and -) a calculation factor relating to the nominal bearing clearance J1 between the balls 5a housed between the inner ring 6b and the outer ring 6a of the ball bearing 5a.

[0071] Obtaining the corrected raceway P3 of the bearing is achieved in particular by correcting the shape of the inner ring 6b of the nominal ball bearing 5a and / or of the nominal rotating shaft 3.

[0072] For example, the correction of the inner ring 6b of the nominal ball bearing 5a is: -) a correction of the overall shape of its internal bore 10 ([Fig.2]) housing the rotating shaft 3, or -) a form correction limited to the nominal race PI of the ball bearing 5a against the inner ring 6b of the nominal ball bearing 5a.

[0073] By way of further examples, the correction of the nominal rotating shaft 3 is: -) a correction to the overall shape of the rotating shaft 3, or -) a form correction limited to the respective outlets 8a of the grooves 8 that the rotating shaft 3 has at its periphery.

Claims

Demands

1. Method of manufacturing the components of a structural assembly (1) of components comprising at least one ball bearing (5) (5a) and at least one rotating shaft (3) having at its periphery at least one axial groove (8) having an opening (8a) at the periphery of the rotating shaft (3), the groove (8) providing a coupling interface between the rotating shaft (3) and at least one rotating component (2b) comprising said structural assembly (1) of components, the ball bearing (5) (5a) comprising an outer ring (6a) and an inner ring (6b) coaxial (Al) which together provide a cage (6) housing at least one set of balls (5a) distributed along a circumference (Cl) centered on an axis (Al) of extension of the ball bearing (5) (5a),at least the inner ring (6b) of the ball bearing (5) (5a) providing at least one bearing race (7b) for the balls (5a) against the outer face of the inner ring (6b) of the ball bearing (5a) (5a), a nominal bearing clearance (J1) being provided between the balls (5a) and the cage (6) of the ball bearing (5a) (5a) which houses them, the manufacturing process being correlated with a coaxial mounting process (Al) by shrink fitting (OF1) of the ball bearing (5a) around the rotating shaft (3) in its axial zone comprising said at least one groove (8) whose opening (8a) is oriented towards the inner ring (6b) which radially closes said opening (8a) of the groove (8) by confining the inner volume of said at least one groove (8),the manufacturing process comprising an initial operation (OP1) of manufacturing the ball bearing (5) (5a) according to nominal characteristics and of manufacturing the rotating shaft (3) according to nominal characteristics in accordance with an axially adjusted fit of the rotating shaft (3) inside the inner ring (6b), characterized in that prior to the shrink-fitting (OF1) of the ball bearing (5) (5a) around the rotating shaft (3) at least in its area having said at least one groove (8), the manufacturing process comprises a determination operation by modeling: -) in a first modeling step (OP2), of an identification of a deformed raceway (P2) of the nominal raceway (PI) of the ball bearing (7b) (5a) against the inner ring (6b) caused by a setpoint clamping force of the rotating shaft (3) by the inner ring (6b) shrink-fitted around the rotating shaft (3) and / or by the presence of said, at least one groove (8), then -) in a second modeling step (OP3) taking into account the identification of the deformed track (P2) previously determined, an identification of a corrected track (P3) of the ball (5a) against the inner ring (6b) by shape correction at least of the nominal track (PI) of the ball (5a) against the inner ring (6b) in accordance with obtaining a restoration of the nominal track (PI) of the ball (7b) in the shrink-fit station of the ball bearing (5a) around the rotating shaft (3).

2. A manufacturing method according to claim 1, characterized in that the modeling identification of said deformed track (P2) takes into account at least the following calculation factors according to at least any combination thereof, at least two by two: -) the width (L1) of the opening (8a) of said at least one groove (8) comprising the rotating shaft (3), -) the thickness (E1) of the inner ring (6b) sought to be as small as possible, -) the material (M1) of the inner ring (6b) identifying at least its characteristics of reversible plasticity under stress, -) the material (M2) of the rotating shaft (3) identifying at least its characteristics of reversible plasticity under stress, and -) the clamping force (EF1) of the rotating shaft (3) by the inner ring (6b) shrink-fitted around the rotating shaft (3) at a predefined clamping force threshold, without being excessive,capable of providing a firm hold for the ball bearing (5) (5a) around the rotating shaft (3).

3. Manufacturing method according to claim 2, characterized in that the identification of the corrected track (P3) takes into account at least the calculation factor relating to the deformed track (P2) and a calculation factor relating to the nominal bearing clearance (Jl) provided between the balls (5a) and the cage (6) of the ball bearing (5) (5a) which houses them.

4. A manufacturing method according to any one of claims 1 to 3, characterized in that the form correction of at least the nominal raceway (PI) of the ball bearing (7b) (5a) against the inner ring (6b) is carried out in accordance with the corrected raceway (P3) previously identified, by correcting the form of at least one of the inner ring (6b) of the ball bearing (5) (5a) and / or the rotating shaft (3).

5. A manufacturing method according to claim 4, characterized in that the form correction of the inner ring (6b) of the ball bearing (5) (5a) is an overall form correction of the inner bore (10) of said inner ring (6b) of the ball bearing (5) (5a).

6. A manufacturing method according to claim 4, characterized in that the form correction of the inner ring (6b) of the ball bearing (5) (5a) is a form correction of the inner bore (10) of the inner ring (6b) of the ball bearing (5) (5a) limited to the extension of the nominal raceway (PI) of the bearing (7b) of the balls (5a) against the inner ring (6b).

7. A manufacturing method according to claim 4, characterized in that the form correction of the rotating shaft (3) is an overall form correction of the conformation of the rotating shaft (3).

8. A manufacturing method according to claim 4, characterized in that the form correction of the rotating shaft (3) is a form correction limited to the outlet (8a) of said at least one groove (8) which comprises the rotating shaft (3).

9. A manufacturing method according to any one of claims 4 to 8, characterized in that the form correction of at least one of the inner ring (6b) of the ball bearing (5a) and / or of the rotating shaft (3) is carried out by machining.

10. A manufacturing method according to any one of claims 1 to 9, characterized in that said structural assembly (1) of components comprising an electric machine (2) combining a stator (2a) cooperating with a rotor (2b), the rotor (2b) having a connecting element (4) for the rotor (2b) with the rotating shaft (3), the volume of the connecting element (4) being calibrated in accordance with a nominal volume at least equivalent to the internal volume of said at least one groove (8) the opening of which (8a) is closed by the inner ring (6b), such that in the assembly station of said connecting element (4) with the rotating shaft (3), said connecting element (4) is at least confined, if not enclosed, within said at least one groove (8), being firmly held between the rotating shaft (3) and the inner ring (6b) of the ball bearing (5) (5a) mounted by shrink fitting around the rotating shaft (3).

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