Process for manufacturing and mounting by shrink-fitting a ball bearing around a rotating shaft.

Abstract

Method for manufacturing and mounting by 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 an operation by modeling (MD) of an identification (OP2) of a deformed track (P2) of the nominal track (P1) of rolling of the balls against its inner ring (6b) by a set shrink-fit force of the inner ring (6b) around the rotating shaft (3), and of an identification (OP3) of a corrected track (P3) of rolling of the balls against the inner ring (6b) by correction of the shape of said nominal track (P1) then carried out (OP4) in accordance with obtaining a restoration of said nominal track (P1) in the shrink-fitting station of the ball bearing (5) around the rotating shaft (3). [Fig. 4]

Description

Title of the invention: Method of 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. The invention relates more specifically to the methods of manufacturing at least one of the components of a structural assembly of components 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 carry out such mounting by shrink-fitting the ball bearing around the rotating shaft. Such a mounting operation is based on a constrained hooping of the rotating shaft by the ball bearing. Typically in the station for mounting the ball bearing 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 arranged between a coaxial inner ring and an outer ring that the ball bearing comprises. The inner ring and the outer ring house between them at least one set of balls that are distributed along a circumference centered around the extension axis of the ball bearing. A nominal rolling clearance of the balls is arranged inside the cage, between the balls on the one hand and the inner ring and the outer ring on the other hand. The same ball bearing may be equipped with several sets of balls distributed axially at a distance from each other inside the cage. Several ball bearings may be mounted around the rotating shaft at an axial distance from each other.

[0004] The concepts "inner" and "outer" are concepts relating to the axis of extension of the ball bearing and / or the axis of rotation of the rotating shaft around which the ball bearing is coaxially mounted. The inner concept is commonly applied to a position close to said axes as opposed to the outer concept applied to a position further from said axes.

[0005] According to an assembly of at least one ball bearing by shrink fitting around the rotating shaft, the ball bearing is positioned axially around the rotating shaft which it grips diametrically. Such a gripping prevents the assembly of the ball bearing around the rotating shaft by hand or with a press. It is therefore customary to heat the inner ring of the ball bearing to expand it prior to installation of the ball bearing around the rotating shaft, and / or conversely potentially to cool the rotating shaft.

[0006] Generally speaking, it is known that a shrink-fitting operation of the inner ring of a ball bearing around a rotating shaft tends to cause deformation of the rotating shaft then subjected to diametrical stresses. In this regard, reference may be made, for example, to document EP4147817 (NTN-SNR ROULEMENTS).

[0007] According to this document, a ball bearing is mounted by shrink-fitting around a hub having an inner bore provided with grooves, via which the hub can be coupled to a drive shaft. To avoid permanent alteration of the grooves after shrink-fitting, the rotating shaft has at its ends plain bearings between which the inner ring of a ball bearing is axially positioned. Prior to the shrink-fitting operation, one of the plain bearings is deformed by bending via a wedge forcibly introduced inside the bore, so that after the shrink-fitting operation the deformed plain bearing resumes its initial conformation under the effect of the stresses it supports.

[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, in particular in the presence of rotating members whose axial extension can generate overhangs.

[0009] More specifically, the usual case is taken into consideration 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 rotating component if necessary, it can be variously arranged, such as for example in a motor shaft for driving the rotating shaft in rotation or conversely in a receiving 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 by the previously mentioned document EP4147817. Another common solution is to couple the rotating shaft to said rotating component by keying, the rotating shaft comprising 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 inappropriately involve a significant diametrical and / or axial increase in the structural assembly of components. More precisely, either the ball bearing(s) is mounted around the splined or grooved keying zone of the rotating shaft - which requires 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) is axially offset from the splined or grooved keying zone of the rotating shaft.

[0012] Failing which, in the case where the ball bearing is mounted around the rotating shaft in its splined or grooved zone, at least one imprint is formed 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 recess(es) formed between the splines or formed by said at least one groove.

[0013] As a result, during rotation of the rotating shaft, such indentations or overall deformation of the rolling track induce a risk of blocking in rotation of the balls rolling against the inner ring, and / or of causing by resonance vibrations which may be significant and harmful to obtaining suitable rotation of the rotating shaft, and / or even of affecting the durability of the ball bearing and / or of the rotating shaft. Presentation of the invention

[0014] In this context, generally according to a synthetic presentation of the invention, the invention relates to a method of manufacturing the components of a structural assembly, comprising at least one rotating shaft provided at its periphery with at least one axial groove, and at least one ball bearing. Said manufacturing method is correlated with a method of mounting by shrink-fitting the ball bearing(s) around the rotating shaft in its axial zone comprising said at least one groove which provides a coupling interface between the rotating shaft and a rotating component that comprises said structural assembly of components.

[0015] Conventionally, to clarify if necessary, it is understood that said at least one groove is for example a keying groove 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 at the periphery of the rotating shaft parallel to its extension axis, presenting an outlet towards the outside of the rotating shaft at its periphery.

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

[0017] On the basis of the observation previously set out and which is part of the approach taken to develop the invention, the invention aims to solve the problem posed - and to overcome the difficulties which result therefrom - of a mounting by shrink fitting of at least one ball bearing around a rotating shaft comprising at its periphery at least one axial groove extending around the periphery of the rotating shaft.

[0018] It is more specifically proposed by the invention to take into account the potential formation of an alteration of the raceway of the balls of the ball bearing which is formed on the outer periphery of the inner ring and / or of at least one imprint which forms locally on said raceway causing its localized alteration. Such alterations of the raceway of the balls against the inner ring of the ball bearing result from the presence of said at least one groove which has an outlet oriented towards the outside of the rotating shaft at its periphery, and from the mounting by shrink-fitting of said inner ring around the rotating shaft which it encloses.

[0019] To do this, initial manufacturing operations of the ball bearing and the rotating shaft are conventionally carried out according to nominal characteristics identifying their structure, their arrangement and / or their 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 preserved after assembly by shrink-fitting the ball bearing around the rotating shaft.

[0020] Prior to mounting the ball bearing around the rotating shaft, the manufacturing method comprises an operation of determining by modeling the deformation of the ball race against the inner ring of the ball bearing, taking into account in particular at least the presence of said at least one groove. Then - from the obtained identification of the deformation of said race - the modeling process continues to determine by modeling a shape correction of the nominal conformation(s) of the ball bearing and / or the rotating shaft, at least with regard to the ball race against the inner ring of the ball bearing.

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

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

[0023] Said modeling identifying on the one hand the deformation of the ball raceway against the inner ring and then on the other hand the corrections to the shape of the inner ring and / or the rotating shaft from the previously obtained identification of the deformation of the raceway, is carried out by taking into account in particular the following calculation factors: a) for the identification of the deformation of the ball raceway against the inner ring - in combination at least two by two - at least: -) the width of said at least one groove which the rotating shaft comprises, -) the thickness of the inner ring - or in other words the radial extension of the inner ring of the ball bearing around the rotating shaft along its outer periphery - which is preferably sought to be as small as possible, -) the material of the inner ring, and more precisely at least its characteristics of reversible plasticity under constraints, and -) the clamping force of the rotating shaft by the inner ring shrunk around the rotating shaft at a desired clamping force threshold - without being excessive - providing firm support for the ball bearing around the rotating shaft. b) then for the identification of the corrections of shapes of the inner ring of the ball bearing and / or of the rotating shaft to be carried out, at least in combination: -) the conformation of the said previously identified deformed raceway, and -) a nominal setpoint clearance of the balls inside the ball bearing cage. As a reminder, the cage is typically arranged between the outer ring and the inner ring of the ball bearing.

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

[0025] It is nevertheless understood that the less advantageous exploitation of other techniques for carrying out the shape corrections to be carried out, such as for example a reversible plastic deformation under stress of the inner ring and / or the rotating shaft, or any other technique(s) capable of materially correcting the nominal characteristics of a mechanical part, in particular in the context of the invention the conformation of the inner ring and / or of the rotating shaft after the identification of the corrections to be made which are precisely obtained advantageously by modeling.

[0026] The corrections to the shape of the inner ring and / or the rotating shaft may, for example, be corrections to their overall conformation. For further examples: -) The correction of the shape of the inner ring can be a correction of the shape of its internal bore, either global or limited to the rolling track of the balls against the inner ring. -) The correction of the shape of the rotating shaft can, for example, still be either limited to its circumference - 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 outlet of the groove intended to be oriented towards the inner ring of the ball bearing after the assembly by shrink fitting of the ball bearing around the rotating shaft.

[0027] An indexing 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 imprint(s) which may form on the ball raceway as a result of the shrinking of the inner ring of the ball bearing around the rotating shaft.

[0028] An advantageous application of the invention is suitable for the rotary assembly between the rotating shaft and a connecting member that comprises a rotor of an electric machine for driving the rotating shaft in rotation, and / or between the rotating shaft and a receiving shaft driven in rotation 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 assembly by keying between the rotating shaft and the rotor of the electrical machine and / or between the rotating shaft and the receiving shaft, promoting the rotational drive and the balancing of the rotation of the rotating shaft by the rotor and / or of the receiving shaft by the rotating shaft.

[0030] The internal volume of the groove(s) being closed by the inner ring of the ball bearing shrunk 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 to be robust, efficient and durable.

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

[0032] The ball bearing typically comprises a coaxial outer ring and an inner ring, which form between them 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 the 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 rolling clearance is provided between the balls and the ball bearing cage which houses them. It is understood but if necessary specified that said nominal rolling clearance is provided between the balls on the one hand and the inner ring and the outer ring of the ball bearing on the other hand.

[0034] The manufacturing method is correlated with a coaxial mounting method by shrink-fitting the ball bearing around the rotating shaft in its axial zone comprising said at least one groove, the outlet of which is oriented towards the inner ring. The inner ring radially closes said outlet of the groove by confining the internal volume of said at least one groove, being included but if necessary specified in its axial zone surrounded by the inner ring.

[0035] The manufacturing method comprises an initial operation of manufacturing the ball bearing according to nominal characteristics and manufacturing the rotating shaft according to nominal characteristics in accordance with a fitted axial fit of the rotating shaft within the inner ring.

[0036] In this context, the invention is recognizable in that prior to the assembly by shrink fitting of the ball bearing around the rotating shaft at least in its zone comprising said at least one groove, the manufacturing method comprises an operation of determining by modeling: -) in a first modeling step, of an identification of a deformed track of the nominal rolling track of the balls against the inner ring caused by a setpoint clamping force of the rotating shaft by the inner ring shrunk 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 rolling the balls against the inner ring by correction of the shape of at least the nominal track for rolling the balls against the inner ring in accordance with obtaining a restoration of the nominal rolling track in the ball bearing shrinking station around the rotating shaft.

[0037] Other specific characteristics of the invention - not restrictive or limiting with regard to other characteristics that it may have - are the following.

[0038] As a 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 one combination between them at least two by two: -) the width of the outlet of said at least one groove which the rotating shaft comprises, -) the thickness of the inner ring advantageously sought preferably as small as possible, -) the material of the inner ring identifying at least its characteristics of reversible plasticity under constraints, -) the material of the rotating shaft identifying at least its characteristics of reversible plasticity under constraints, and -) the setpoint force for clamping the rotating shaft by the inner ring shrunk around the rotating shaft at a predefined clamping force threshold, without being excessive, capable of providing firm support for the ball bearing around the rotating shaft.

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

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

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

[0042] The shape correction of the inner ring of the ball bearing is, for example, also a shape correction of the inner bore of the inner ring of the ball bearing, which is limited to the extension of the nominal rolling track of the balls 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 shape correction of the rotating shaft is for example still a correction of shape limited to the outlet of said at least one groove that the rotating shaft comprises.

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

[0046] As a non-restrictive example of an application of the invention to a said structural assembly of components to be assembled together, said structural assembly of components comprises an electrical machine associating a stator and a rotor. The rotor comprises a member for joining the rotor with the rotating shaft. The volume of the joining member is calibrated in accordance with a nominal volume at least equivalent to the internal volume of said at least one groove, the outlet of which is closed by the inner ring.

[0047] In other words, the manufacture of the connecting member to its nominal volume is correlated with the manufacture of the rotating shaft and more specifically with the operation of forming said at least one groove formed on the periphery of the rotating shaft. In the station for assembling said connecting member with the rotating shaft, said connecting member is at least confined if not clamped inside said at least one groove, while 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 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.l] is an illustration for example of a context of application of the present invention to a partially represented electrical machine. According to this example, the structural assembly of components at least comprises the electrical machine associating a stator and a rotor for driving a rotating shaft in rotation. For its rotational drive, the rotating shaft is connected to the rotor by a connecting member housed inside peripheral axial grooves that the rotating shaft comprises, each of which has an outlet oriented towards a ball bearing mounted by shrink fitting around the rotating shaft. [Fig.2] is a representation of the ball bearing mounted by shrink fitting around the rotating shaft which comprises the structural assembly of components illustrated in [Fig.l]. [Fig.3] is a diagram illustrating the problem to be solved by the invention and schematically the methods of its resolution. 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 configurations- technically represented for educational purposes. [Fig.4] is a flowchart illustrating methods for determining by modeling a modification of the shape of the profile of the rolling track with reference to the different conformations of the profile of the rolling track shown diagrammatically in [Fig.3]. Detailed description of the invention

[0049] The figures and their detailed non-limiting descriptions set out the invention according to particular methods which are not restrictive as to the scope of the invention. The figures and their detailed descriptions of an exemplary embodiment of the invention can be used to better define it, if necessary in relation to the general description which has just been given. Furthermore, to avoid overloading the figures and thus facilitate their reading, the reference numbers assigned to the terms and / or concepts used to describe the invention and indicated in any one of the figures are potentially repeated in the description of any other figure without implying their presence in all of the figures.

[0050] In [Fig.l], there is shown for example a structural assembly 1 of components comprising an electrical machine 2 conventionally implementing a stator 2a and a rotor 2b cooperating with each other. The rotor 2b is linked in rotation with a rotating shaft 3 for its rotational drive by the rotor 2b, via a connecting member 4 which the rotor 2b comprises. The rotating shaft 3 is equipped with at least one ball bearing 5a, a single ball 5a being referenced so as not to weigh down the [Fig.l]. The ball bearing 5a is mounted coaxially Al by shrink fitting around the rotating shaft 3. As a result of their coaxial mounting Al, the axis of the ball bearing 5a and the axis of the rotating shaft 3 are identified according to the same reference Al to simplify the reading of the figures and facilitate the presentation of the invention and / or its understanding.

[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 participating in 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] More clearly visible in [Fig.2], rolling tracks 7a, 7b of 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 rolling clearance J1 of the balls 5a inside the cage 6 - along the circumference C1 of their distribution inside the cage 6 - is provided inside the cage 6 between the balls 5a on the one hand and on the other hand between the outer ring 6a and the inner ring 6b of the ball bearing 6a.

[0054] According to the example of application of the invention to an electrical machine 2 illustrated in [Fig.l], 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 comprises a component forming said axial and rotating junction member 4 between the rotor 2b and the rotating shaft 3 for its rotational drive by the rotor 2b.

[0055] In [Fig.l] and more visible in [Fig.2], the ball bearing 5a is mounted by shrink fitting around the rotating shaft 3. For assembly between the rotating shaft 3 and the rotor 2b, the rotating shaft 3 has at its periphery at least one groove 8 for receiving the connecting member 4 of the rotor 2b. According to the example illustrated, the rotating shaft 3 preferably has a pair of two diametrically opposed grooves 8 on the periphery of the rotating shaft 3. Each of the grooves 8 has an opening 8a open on the periphery of the rotating shaft 3 on 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 arise from the observation that following the assembly by shrink fitting of the ball bearing 5a around the rotating shaft 3 via the inner ring 6b of the ball bearing 5a, the nominal rolling track PI of the balls 5a against the inner ring 6b deforms under the effect of the diametrical stress supported by the inner ring 6b and by the presence of the grooves 8 which the rotating shaft 3 comprises.

[0057] The deformation of said nominal track PI for rolling the balls 5a against the inner ring 6b may be global and / or be localized by the formation of impressions 9 on said nominal track PI for rolling the balls 5a.

[0058] Such deformations of the nominal rolling track PI of the balls 5a are formed under the effect of the gripping of the rotating shaft 3 by the inner ring 6b then subjected to diametrical stresses. The formation of the impressions 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 rotational blocking of the balls 5a rolling inside the cage 6 which houses them, the deformation of the inner ring 6b being able to absorb all or part of the nominal rolling clearance J1 of the balls 5a provided between the balls 5a and the rings 6a, 6b constituting the ball bearing 5a. It is also noted in particular that the deformation of the nominal rolling track PI of the balls 5a against the inner ring 6b causes, as a result of the rolling of the balls 5a against the inner ring 6b, vibrations which can be significant and harmful to obtaining balanced rotation of the rotating shaft 3.

[0060] To overcome such drawbacks, the invention proposes a method of manufacturing the components of a 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 understanding of the description of the invention, the description of said manufacturing method is correlated with the technique of mounting by shrink fitting the ball bearing 5a around the rotating shaft 3 and the methods of joining the rotating shaft 3 with a motor shaft rotating the rotating shaft 3 and / or a receiving shaft rotated 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 rolling track of the balls 5a against the inner ring 6b of the ball bearing 5a are illustrated in the same figure. It is specified but obviously understood that the three rolling tracks shown are illustrative, without prejudging their actual conformations which depend on the specific cases of application of the invention and / or the result of their identification by modeling as described later in relation to [Fig. 4].

[0062] The three rolling tracks of the balls 5a against the inner ring 6b of the ball bearing 5a illustrated in [Fig.3] are as follows: -) a first rolling track is the nominal rolling track PI obtained according to the initial nominal manufacturing characteristics of the 5a ball bearing 5 subsequently designated nominal 5a ball bearing; -) a second rolling track is a deformed rolling track P2, as a result of the shrink-fitting of the nominal ball bearing 5a around the rotating shaft 3, which causes - as previously mentioned - a deformation of the nominal rolling track 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 rolling track is a corrected rolling track P3 of the nominal rolling track PI prior to the shrinking of the ball bearing 5a around the rotating shaft 3, it being understood that the ball bearing 5a shrinked around the rotating shaft 3 is the ball bearing 5a comprising the corrected rolling track P3.

[0063] As a reminder concerning the deformed rolling track P2, the deformation of the nominal rolling track PI into a deformed rolling track P2 results from the assembly by shrink fitting of the nominal ball bearing 5a causing the overall deformation - and / or the formation of localized impressions 9 - of the nominal rolling track PI into a deformed rolling track P2.

[0064] So that - following the shrink-fitting assembly OF1 ([Fig.4]) of the ball bearing 5a around the rotating shaft 3 - the rolling track 7b of the balls 5a against the inner ring 6b conforms to the nominal rolling track PI, it is proposed by the invention to correct the conformation of the nominal rolling track PI in a called corrected P3 rolling track taking the conformation of the nominal PI rolling track after assembly by OF1 shrink fitting of the ball bearing 5a around the rotating shaft 3.

[0065] For this purpose, referring 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: -) OP1 conventionally manufacture the 5 ball bearing 5a in accordance with its nominal characteristics C5 - and therefore including in particular said nominal raceway PI for rolling the balls 5a and the nominal clearance J1 for rolling the balls 5a inside the cage 6 arranged between the upper ring and the lower ring of the 5 ball bearing 5a - and OP1 manufacture 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 outlet 8a of the grooves 8 oriented towards the inner ring 6b of the 5 ball bearing 5a, then -) correct OP4 from the identification of said deformed rolling track P2 of the balls 5a against the inner ring 6b of the ball bearing 5a, the rolling track 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 rolling track PI carried out, the rolling track 7b of the balls 5a of the ball bearing 5a mounted by shrink fitting OF1 around the rotating shaft 3 resumes by deformation of the inner ring 6b of the ball bearing 5a its nominal characteristics in accordance with the nominal rolling track PI, and the nominal rolling clearance J1 of the balls 5a inside the cage 6 which houses them is maintained. Thus, when the rotating shaft 3 is rotated, a risk of the balls 5a rolling inside the cage 6 which houses them becoming blocked in rotation is avoided and the generation of vibrations is prevented.

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

[0068] The determination by modeling of the deformation of the rolling track 7b of the balls 5a against the inner ring 6b takes into account at least the following calculation factors. It is hereby specified that said calculation factors are mentioned for non-restrictive information purposes, being taken into account according to at least one combination between them at least two by two depending on the application case and / or the context for which the invention is used, is included or relates.

[0069] Concerning the determination OP2 by modeling of said deformed rolling track P2, the following are taken into account, for example: -) the width L1 of the outlet 8a of said at least one groove 8 which the rotating shaft 3 comprises, -) the thickness El of the inner ring 6b sought as low 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 constraints, and -) the set force EF1 for clamping the rotating shaft 3 by the inner ring 6b shrunk around the rotating shaft 3 at a desired clamping force threshold, without being excessive, providing firm support for the ball bearing 5a around the rotating shaft 3.

[0070] Concerning the determination OP3 by modeling the corrected rolling track P3 - or in other words more generally the correction of the shape of the rolling track 7b of the balls 5a against the outer face of the inner ring 6b - it is taken into account in combination at least: -) the calculation factor relating to the previously identified deformed P2 rolling 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 rolling track P3 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 shape correction limited to the nominal PI raceway of the balls 5a against the inner ring 6b of the nominal 5a ball bearing 5.

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

Claims

Claims

1. Method for manufacturing the components of a structural assembly (1) of components at least comprising at least one ball bearing (5) (5a) and at least one rotating shaft (3) provided at its periphery with at least one axial groove (8) comprising an outlet (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) that comprises said structural assembly (1) of components, the ball bearing (5) (5a) comprising a coaxial outer ring (6a) and an inner ring (6b) (Al) which provide between them 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 raceway (7b) for the balls (5a) against the outer face of the inner ring (6b) of the ball bearing (5) (5a), a nominal bearing clearance (J1) being provided between the balls (5a) and the cage (6) of the ball bearing (5) (5a) which houses them, the manufacturing method being correlated with a coaxial mounting method (Al) by shrink fitting (OF1) of the ball bearing (5) (5a) around the rotating shaft (3) in its axial zone comprising said at least one groove (8) whose outlet (8a) is oriented towards the inner ring (6b) which radially closes said outlet (8a) of the groove (8) by confining the internal volume of said at least one groove (8),the manufacturing method 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 adjusted axial 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 comprising said at least one groove (8), the manufacturing method comprises an operation of determining by modeling: -) in a first modeling step (OP2), an identification of a deformed track (P2) of the nominal track (PI) of rolling (7b) of the balls (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 previously determined deformed track (P2), an identification of a corrected track (P3) of rolling (7b) of the balls (5a) against the inner ring (6b) by correction of shape at least of the nominal track (PI) of rolling (7b) of the balls (5a) against the inner ring (6b) in accordance with obtaining a restoration of the nominal track (PI) of rolling (7b) in the shrink-fitting station of the ball bearing (5) around the rotating shaft (3).

2. Manufacturing method according to claim 1, characterized in that the identification by modeling of said deformed track (P2) takes into account at least the following calculation factors according to at least one combination between them at least two by two: -) the width (Ll) of the outlet (8a) of said at least one groove (8) that the rotating shaft (3) comprises, -) the thickness (El) of the inner ring (6b) sought to be as small as possible, -) the material (Ml) 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 set force (EF1) for clamping the rotating shaft (3) by the inner ring (6b) shrunk around the rotating shaft (3) at a predefined clamping force threshold, without being excessive,capable of providing firm support for the ball bearing (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) which houses them.

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

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

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

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

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

9. Manufacturing method according to any one of claims 4 to 8, characterized in that the shape 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. Manufacturing method according to any one of claims 1 to 9, characterized in that said structural assembly (1) of components comprising an electrical machine (2) associating a stator (2a) cooperating with a rotor (2b), the rotor (2b) comprising a junction member (4) for joining the rotor (2b) with the rotating shaft (3), the volume of the junction member (4) is calibrated in accordance with a nominal volume at least equivalent to the internal volume of said at least one groove (8) whose outlet (8a) is closed by the inner ring (6b), so that in the assembly station of said junction member (4) with the rotating shaft (3), said junction member (4) is at least confined if not clamped inside 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).

Images