WO2020183091A1

WO2020183091A1 - Method for manufacturing a splined hub, splined hub, and vehicle comprising a hub

Info

Publication number: WO2020183091A1
Application number: PCT/FR2020/050420
Authority: WO
Inventors: Andre Game
Original assignee: Psa Automobiles Sa
Priority date: 2019-03-13
Filing date: 2020-03-03
Publication date: 2020-09-17
Also published as: FR3093776B1; FR3093776A1

Abstract

Hub (1) comprising: - a bore (2) that comprises an internal spline (3) formed on its periphery, this internal spline (3) comprising a first and a second part, this second part comprising a free end (4) of the internal spline (3), - an attached ring (7) coaxial with this bore (2), this ring (7) being securely fixed to the hub (1) and comprising the second part, the first part comprising a first flank surface and the second part comprising a second flank surface in the continuation of the first flank surface, these first and second surfaces forming a flank of the internal spline (3).

Description

DESCRIPTION

TITLE OF THE INVENTION: PROCESS FOR MANUFACTURING A ROD HUB, ROD HUB, AND VEHICLE INCLUDING A HUB.

The present invention claims the priority of the French application

N ° 1902546 filed on 13.03.2019 whose content (te <te, drawings and

claims) is incorporated herein by reference.

[0002] The invention relates to a method of manufacturing a hub and a hub, this hub comprising a central bore defining an axis, and comprising so-called "internal" or female splines formed on the periphery of this bore.

[0003] In contrast, the splines formed on the periphery of a shaft assembled in this hub are called "external" or male splines.

[0004] The invention relates in particular to a hub of a coupling device between an engine and a gearbox, in particular a clutch hub, a hub in which an input shaft of the gearbox is fitted. , said primary shaft.

It is known that each spline of the splined hub comprises at least a first free end which engages between two successive external splines of the shaft during the assembly of this shaft in this hub, each of the external splines of the 'shaft comprising a second free end which engages between two successive internal splines of the hub. This engagement is sometimes delicate, in particular for blind assemblies by operators, the latter therefore not being able to visually align the external splines between the internal splines before the shaft is fitted into the hub.

[0006] It is then known from patent document FR-A1 -3029166 a tool for indexing in rotation a splined hub of an engine clutch with a primary gearbox shaft.

[0007] Unfortunately, this tool requires an additional assembly line operation which is manual, and penalizes the cycle time of the line. [0008] It is then known, for example, from patent document CH-A-323414, that the first and second ends end in the form of a point to facilitate the engagement of the shaft in the hub.

[0009] Unfortunately, the method of manufacturing the tips of the first

free ends is complex because processes such as slotting or broaching have a straight machining direction along the axis. Thus, to achieve these points, it is necessary to carry out a machining restart with a special small-size milling cutter, since the first free ends are not easily accessible for the milling cutter because of the size of the hub, in particular when these first ends are set back relative to a face of the hub via which the shaft is engaged.

[0010] The aim of the invention is to optimize this hub, so as to no longer have

need to use this special cutter.

[0011] To this end, the invention relates to a method for manufacturing a hub, this hub comprising:

- A bore which comprises an internal spline formed on its periphery, this internal spline comprising a first and second part, this second part comprising a free end of the internal spline intended to engage between two successive external splines of a shaft during the assembly of this shaft in the bore,

- an attached ring coaxial with this bore, this ring being fixedly secured to the hub and comprising the second part,

the first part comprising a first sidewall surface and the second part comprising a second sidewall surface in continuity with the first sidewall surface, this first and second surface forming a sidewall of the internal groove, the method being such that it successively comprises :

- a first step of making the internal groove, the first part being made in the bore separately from the second part made in the ring, then,

- a second step of shrinking the ring in the hub.

[0012] Thus the realization of the free end can be done independently of

the size of the hub. The realization of the free end is done only on the ring, outside the hub and before the ring is inserted into it. The realization of the free end is therefore simplified.

[0013] In addition, this ring being, after assembly in the hub, integral

fixed to the hub by shrinking, the second sidewall surface also participates in the transmission of torque from the shaft to the hub, thus avoiding increasing inter-tooth contact pressure on the first sidewall surface. This inter-tooth contact pressure is due to the torque transmitted, and is the mechanical pressure exerted between the internal and external splines. The shrinking step allows the ring to be secured to the hub with a controlled deformation of the ring, and in particular a controlled deformation of the second part of the internal spline, which allows this second part to be produced before the ring has either shrunken: the shape of the second part can be calculated and produced separately from the hub, so as to obtain the desired precise shape without machining this second part, once shrunk in place in the hub, by application of a reverse deformation due hooping.

According to one embodiment of the invention, the second step comprises a first sub-step of angular indexing of the ring relative to the hub, so that the first sidewall surface and the second sidewall surface are continuous once the hooping is complete.

Indeed, the second sidewall surface participates in the transmission of this torque, it is therefore in surface continuity with the first sidewall surface, so that it does not protrude or recede from the first sidewall surface so as not to concentrate the inter-tooth contact pressure on the first or second sidewall surface. Likewise, the continuity makes it possible not to have space between the first and the second part, always in order not to increase the inter-tooth pressure.

[0016] Thus, this first sub-step allows that, although the internal spline is divided into two parts, this internal spline has a continuity of contact with the external spline of the shaft which transmits torque to it.

[0017] According to one embodiment of the invention, the second step of shrinking the ring comprises a second sub-step for cooling the ring then a third sub-step of introducing the ring into the hub. According to one embodiment of the invention, the first sub-step is carried out after the third sub-step.

[0019] The subject of the invention is also a hub comprising:

the first part comprising a first sidewall surface and the second part comprising a second sidewall surface in continuity with the first sidewall surface, this first and second surface forming a sidewall of the internal spline, this hub being as produced according to the method described above.

[0020] It should be noted that the spline generally has two flanks, one or the other transmitting the torque according to the direction of this torque. This invention applies in the same way to each of these two sides.

[0021] In an alternative embodiment, the ring comprises the free ends of all the internal grooves.

[0022] According to an embodiment of the invention, the second part comprises two second side surfaces each extending along the axis of the internal groove by an engagement surface, these two surfaces

of engagement approaching each other to complete the free end in a point shape.

[0023] Thus the insertion of the shaft into the hub is facilitated, even when

the operator makes this assembly blind. It also makes it easier to automate this assembly, especially if the outer splines also have two engagement surfaces that come close to each other.

We will understand by engagement surface, throughout the text of this

document, any surface of the internal groove excluded from the surfaces of the flanks, and capable of orienting the shaft angularly relative to the hub when this shaft is introduced into the internal splines of the hub. Thus, during a step of introducing the shaft into the hub, at least one surface

engagement ring will contact a free end of an outer spline and will angularly index the shaft with respect to the internal splines.

[0025] According to one embodiment of the invention, these two engagement surfaces are symmetrical with respect to a median plane of the groove.

[0026] According to one embodiment of the invention, these two engagement surfaces meet so that the tip shape is complete.

[0027] This is the configuration that allows the greatest ease of engagement of

the shaft in the hub, because there is no longer any surface of the internal splines that could oppose the introduction of the shaft into the hub. Only the end of the point can still oppose it, this possibility then having a zero probability if the outer grooves also have two engagement surfaces approaching each other and meeting at a point.

[0028] According to a particular embodiment of the invention, at least one of the two engagement surfaces is a chamfer.

[0029] This is indeed an easy to machine form of engagement surface, but

other more complex shapes can be envisaged, in particular concave or convex shapes.

[0030] According to one embodiment of the invention, the attached ring is shrunk into the hub.

This hooping allows the ring to be fixedly secured to the hub.

[0032] It will be noted that this ring has its own existence independently of the

hub, before this ring is shrunk into the hub. The object of this invention relating to the hub with this assembled ring, that is to say that the hub comprises this ring, for convenience of language, throughout the text of this document the term hub designates both the hub with the ring as the hub without the ring, the context giving one or the other meaning of the term hub.

[0033] According to a particular characteristic of the invention, the second part has a groove length between 5 and 20% of the total length of the groove internal, these lengths being measured on the root diameter of the internal groove.

The length of groove will be understood to mean the length of a neutral fiber of this groove, at a tooth height corresponding to the root diameter of the groove.

[0035] According to one embodiment of the invention, the first and the second part are made with a steel of the same composition.

[0036] According to one embodiment of the invention, the steel of the second part has undergone a heat treatment resulting in a surface hardness greater than that of the first part.

[0037] According to an alternative embodiment of the invention, the first and the second part are made of different materials, in particular respectively forged steel and sintered steel.

[0038] According to an alternative embodiment of the invention, the attached ring is

entirely carried out by sintering.

[0039] Thus, thanks to the attached ring which allows sintering, the free end can be of complex shape while producing the attached ring in a single sintering operation, and therefore without any machining. It should also be noted that sintering makes it possible to take into account, by anticipation, the deformation of the ring due to the shrinking of this ring in the hub: the shape of the second part can be calculated and produced separately from the hub, so as to obtain the desired precise shape without machining of this second part, once shrunk in place in the hub, by application of a reverse deformation due to shrinking.

[0040] According to one embodiment of the invention, the hub comprises a clutch disc.

The invention also relates to an assembly device by splines comprising a shaft, a free end of which comprises external splines, and a hub as described above, the shaft fitting into the internal splines of the hub by the free ends of the internal splines of the hub. [0042] The invention also relates to a vehicle comprising an assembly device as described above, the shaft being a primary shaft of a gearbox, the hub being a hub of a clutch.

[0043] The subject of the invention is also a vehicle comprising a hub as described above.

[0044] Other characteristics, aims and advantages of the invention will become apparent on reading the description of the non-limiting exemplary embodiments which follow, made with reference to the appended Figures 1 to 6, which represent:

[0045] [Fig.1] shows an example of a partial cross section of a hub provided with internal splines according to the invention, at a middle position of the internal splines with respect to their length.

[0046] [Fig.2] shows a sectional view of a ring according to the invention, before assembly in the hub, and a sectional view of the hub comprising this ring assembled according to the invention.

[0047] [Fig.3] shows a sectional view of the internal grooves according to their

pitch diameter, with free ends according to a first variant of the invention.

[0048] [Fig.4] shows a side view of an internal groove in a plane

comprising the axis of the hub, with free ends according to a second variant of the invention.

[0049] [Fig.5] shows a sectional view of the internal grooves according to their

pitch diameter, with free ends according to the second variant of the invention.

[0050] [Fig.6] shows a sectional view of the internal grooves according to their

pitch diameter, with free ends according to a third variant of the invention.

[0051] It should be borne in mind that the figures are given by way of example and are not limiting of the invention. They constitute representations

Schematic diagrams intended to facilitate understanding of the invention and are not necessarily on the scale of practical applications. In particular, the dimensions of the various elements illustrated are not representative of reality.

In what follows, the figures are to be taken in combination with each other for the recognition of the designated numerical references.

Figure 1 shows a hub 1 comprising a bore 2 which comprises internal splines 3 formed on its periphery, a shaft 6 provided with at least two successive external splines 5. At least one internal spline 3 is engaged between these two splines successive external 5. These

internal and external splines 3, 5 are regularly distributed on the periphery of the bore 2 and the shaft 6, respectively.

[0054] Figure 1 further illustrates two first flank surfaces 100, 101 of the internal splines 3, and a root diameter D1 of the internal splines 3. The first two flank surfaces 100, 101 are involute flanks, these internal grooves 3 therefore have a pitch diameter D2 which will be used subsequently for section planes. But these sidewalls 100, 101 can be of another shape, for example parallel straight sides. Likewise, the internal splines 3 shown are straight splines, that is to say that the median plane along the length of each spline comprises the axis of the hub, but other types of splines are conceivable such as helical splines. , the invention being equally applicable to all variants of internal splines.

In all cases, these internal grooves 3 also have a head diameter, D3.

[0056] Figure 2 illustrates the hub 1 in longitudinal section, this hub 1

comprising the bore 2 which comprises;

an internal groove 3 formed on its periphery, this internal groove 3 comprising a first 8 and second 9 part, this second part 9 comprising a free end 4 of the internal groove 3 intended to engage between the two successive external grooves 5 of shaft 6 when

the assembly of this shaft 6 in the bore 2,

- a ring 7 attached coaxial with this bore 2, this ring 7 being fixedly secured to the hub 2 and comprising the second part 9, the first part 8 comprising the first sidewall surface 100, 101 and the second part 9 comprising a second sidewall surface 102, 103 in continuity with the first sidewall surface 100, 101, this first and second surface forming a side of the internal groove 3 (the two second flank surfaces 102, 103, and the first and second part 8, 9, are illustrated in the following figures).

Note that the two second sidewall surfaces 102, 103 belong to the attached ring 7, while the first two sidewall surfaces 100, 101 do not belong to the attached ring 7, but to the hub 1 without the ring attached 7, that is to say before this ring 7 is assembled in the hub 1.

[0058] Figure 2 further illustrates a method of manufacturing a hub 1 as described above, symbolized by the arrow.

This method comprises:

- a first step of making the internal groove 3, the first part 8 being made in the bore 2 separately from the second part 9 made in the ring 7, then,

- a second step of shrinking the ring 7 in the hub 1.

This second step includes a first indexing sub-step

angular of the ring 7 relative to the hub 1, so that the first sidewall surface 100, 101 and the second sidewall surface 102, 103 are continuous once the hooping is completed, to align the first two sidewall surfaces 100, 101 with the second flank surfaces 102, 103.

This second step of shrinking the ring 7 comprises a second sub-step for cooling the ring 7 and then a third sub-step of introducing the ring 7 into the hub 1 until the two second surfaces flank 102, 103 and the first two flank surfaces 100, 101 are surface continuity. This second sub-step of cooling the ring 7 can be completed by heating the hub 1 and vice versa.

The first sub-step is carried out, for example, but not necessarily after the third sub-step. For example, an outer diameter 10 of the ring 7 is slightly larger than a bore 1 1 of the hub 1, this ring 7 being inserted until it abuts the bottom 12 of the bore 11 by this process , thus allowing surface continuity.

It will be noted that the first angular indexing sub-step of the ring 7 relative to the hub 1 is carried out for example by means of a splined shaft of a mounting device (not shown) which, by a specific adjustment with the internal splines 3, is inserted into the hub 1 after the introduction of the ring 7, or at the same time.

[0065] Figure 3 illustrates a sectional view of several internal grooves 3 along their original diameter D2, with free ends 4 according to a first variant of the invention. The second part 9 comprises two second flank surfaces 102, 103, each extending along the axis of the internal groove 3 by an engagement surface 104, 105, these two engagement surfaces 104,

105 approaching each other to complete the free end 4 in the form of a point. This first variant is remarkable in that one of the second sidewall surfaces 103 coincides with one of the engagement surfaces 105, so that this engagement surface 105 is not referenced in this figure 3. Despite all, the engagement surface 104 comes close to the second sidewall surface 103 and therefore to the engagement surface 105, ending the free end 4 in the form of a point. Note that the tip shape of this first variant is not complete, that is to say that the nose of the tip is truncated, even at the root diameter D1. This characteristic makes it possible to have a free end 4 which is not fragile. It will also be noted that the tip shape is not symmetrical: in fact, this first variant allows an economy of machining, only one of the two second flank surfaces 102, 103 being machined to form only one of the two engagement surfaces. 104, 105.

It will also be noted that the engagement surface 104 is inclined axially, relative to the axis of the groove, to form the point, but is also inclined radially, therefore forming an angle with respect to the radius passing through the foot of the spline and the axis of the hub 1, so as to form a relief angle of the internal spline 3, this radial inclination being the mean radial inclination of the same slope as the second side surface 102. But this radial inclination of the engagement surface 104 is not essential, as we will see in the following variants: in fact, these engagement surfaces 104, 105 are produced when the ring 7 has not yet been introduced into the hub 1, and therefore before the third sub-step of introducing the ring 7 into the hub 1. Thus, the production of these surfaces

of engagement is technically much less constrained and the shape of these engagement surfaces 104, 105 can therefore be arbitrary. However, for the sake of simplicity, a flat engagement surface 104, 105 should be preferred.

[0067] Figures 4 and 5 illustrate the free end 4 according to a second variant of the invention, and will therefore be described together below.

The two engagement surfaces 104, 105 are symmetrical with respect to the median plane of the groove 3, and meet so that the tip shape is complete, that is to say that the nose of the tip is not truncated, at least at the level of the root diameter D1. So as to avoid injuries to operators, when handling the parts and in particular the attached ring 7, a frustoconical surface 106 can be produced on the free end 4, the top of this surface being the nose of the point at the end. level of the root diameter D1, the base being one of the head circles D3 of the free end 4.

[0069] For example, at least one of the two engagement surfaces 104, 105 is a chamfer, and therefore a planar engagement surface. In particular in this second variant, the two engagement surfaces 104, 105 are chamfers orthogonal to the bottom of the internal grooves 3, that is to say that the radial inclination of the engagement surfaces 104, 105 is zero.

In addition, Figure 4 illustrates the fact that the second part 9 has a length of groove L1 between 5 and 20% of the total length L2 of the internal groove 3, these lengths L1, L2 being measured on the diameter of foot D1 of the internal groove 3. Indeed, beyond 25%, the shrinking becomes delicate, but above all from the point of view of mechanical strength it is important to maximize the continuity of material between the first and the second part 8, 9 In addition, in order to be able to produce a sufficiently closed tip shape to allow guiding of the shaft 6, a length L1 greater than 5% of the length L2 is to be preferred. In all the variants described, and in all the figures showing the attached ring 7 in section, the hatching of the ring 7 is different from those of the hub 1. This in order to visually clearly distinguish the ring 7 from the hub 1.

It is recalled here that this ring 7 has its own existence independently of the hub 1, before this ring 7 is assembled in the hub 1. The object of this invention relating to the hub 1 with this ring 7 assembled, c 'that is to say that the hub 1 includes this ring 7, for convenience of language, throughout the text of this document the term hub 1 designates both the hub 1 with the ring 7 and the hub 1 without the ring 7, the context giving one or the other meaning of the term hub 1.

In a first sub-variant, the first and the second part 8, 9 are for example made with a steel of the same composition. But the steel of the second part 9 has, for example, a heat treatment resulting in a surface hardness greater than that of the first part 8. Thus the internal groove 3 of the second part 9 will not chip during the shocks caused. by the contact of the shaft 6 on the two engagement surfaces 104, 105, while at the same time the first part 8 is capable of transmitting a large torque without risking the appearance of initiation of rupture of the internal spline 3.

According to a second sub-variant, the first and the second part 8, 9 are made of different materials, in particular respectively of forged steel and of sintered steel. The advantage of sintered steel is that it is possible to make the insert ring 7 with complex free end shapes 4 in a single operation.

[0075] Figure 6 discloses a sectional view of the internal grooves 3 along their original diameter D2, with free ends 4 according to a third variant of the invention. This third variant is simply the second variant, but without the frustoconical surface 106.

This hub 1 finds particular application in the field of

mechanical transmissions, in particular automobiles. Thus, the hub 1 comprises, for example, a clutch disc.

This hub 1 is advantageously integrated into an assembly device by splines comprising a shaft 6, a free end of which comprises external splines 5, and a hub 1 as described above, the shaft 6 fitting into the internal splines 3 of the hub 1 via the free ends 4 of the internal splines 3 of the hub 1.

[0078] For example, a vehicle includes this assembly device such as

previously described, the shaft 6 being a primary shaft 6 of a gearbox, the hub 1 being a hub 1 of a friction clutch.

For example, and more generally, a vehicle comprising a hub & as described above.

[0080] Other applications can be envisaged, in particular for a homokinetic ball joint shaft engaging in a nut (the hub). !

Claims

[Claim 1] A method of manufacturing a hub (1), this hub (1) comprising:

- a bore (2) which comprises an internal spline (3) formed on its periphery, this internal spline (3) comprising a first (8) and second (9) part, this second part (9) comprising a free end (4) ) of the internal spline (3) intended to engage between two successive external splines (5) of a shaft (6) during the assembly of this shaft (6) in the bore (2),

- a ring (7) attached coaxial to this bore (2), this ring (7) being fixedly secured to the hub (1) and comprising the second part (9), the first part (8) comprising a first side surface ( 100, 101) and the second part (9) comprising a second sidewall surface (102, 103) in continuity with the first sidewall surface (100, 101), this first and second surface forming a side of the internal groove (3 ), characterized in that the method comprises successively:

- a first step of making the internal groove (3), the first part (8) being made in the bore (2) separately from the second part (9) made in the ring (7), then,

- a second step of shrinking the ring (7) in the hub (1).

[Claim 2] A method according to claim 1, characterized in that the second step comprises a first sub-step of angular indexing of the ring (7) relative to the hub (1), so that the first side surface (100 , 101) and the second sidewall surface (102, 103) are continuous once the hooping is complete.

[Claim 3] A method according to claim 2, characterized in that the second step of shrinking the ring (7) comprises a second sub-step of cooling the ring (7) then a third sub-step of introducing the ring (7). ring (7) in the hub (1).

[Claim 4] A method according to claim 3, characterized in that the first sub-step is carried out after the third sub-step. [Claim 5] Hub (1) comprising:

- a bore (2) which comprises an internal spline (3) formed on its periphery, this internal spline (3) comprising a first (8) and second (9) part, this second part (9) comprising a free end (4) ) of the internal groove (3) intended to engage between two successive external grooves

(5) of a shaft (6) when assembling this shaft (6) in the bore (2),

- a ring (7) attached coaxial to this bore (2), this ring (7) being fixedly secured to the hub (1) and comprising the second part (9), the first part (8) comprising a first side surface ( 100, 101) and the second part (9) comprising a second sidewall surface (102, 103) in continuity with the first sidewall surface (100, 101), this first and second surface forming a side of the internal groove (3 ),

characterized in that this hub (1) is produced according to a method according to any one of the preceding claims.

[Claim 6] A hub (1) according to claim 5, characterized in that the second part (9) comprises two second side surfaces (102, 103) each extending along the axis of the internal groove (3) by a engagement surface (104, 105), these two engagement surfaces (104,

105) approaching each other to complete the free end (4) in a point shape.

[Claim 7] A hub (1) according to claim 6, characterized in that these two engagement surfaces (104, 105) are symmetrical with respect to a median plane of the spline (3).

[Claim 8] A hub (1) according to claim 6 or 7, characterized in that these two engagement surfaces (104, 105) meet so that the tip shape is complete.

[Claim 9] A hub (1) according to any one of claims 6 to

8, characterized in that at least one of the two engagement surfaces (104, 105) is a chamfer.

[Claim 10] A hub (1) according to any one of claims 5 to

9, characterized in that the second part (9) has a groove length (L1) between 5 and 20% of the total length (L2) of the internal groove (3), these lengths (L1, L2) being measured on the root diameter (D1) of the internal spline (3).

[Claim 11] Hub (1) according to any one of claims 5 to 10, characterized in that the first and the second part (8, 9) are made from a steel of the same composition.

[Claim 12] Hub (1) according to claim 1 1, characterized in that the steel of the second part (9) has undergone a heat treatment

resulting in a surface hardness greater than that of the first part (8).

[Claim 13] A hub (1) according to any one of claims 5 to 10, characterized in that the first and the second part (8, 9) are made of different materials, in particular respectively forged steel and sintered steel.

[Claim 14] Vehicle comprising a hub (1), characterized in that this hub (1) conforms to any one of claims 5 to 13