FR3103402A1 - Machining process of a part - Google Patents

Abstract

The invention relates to a method of machining a part (1) having a first surface (2), a second surface (3) and a reference surface (4), said method successively providing to: take charge of said part by means of a first tool (6) having a first wall (7); immobilize said part in a machining position in which the reference surface (4) of said part abuts on the first wall (7); machining said first surface of said workpiece; supporting said part in the machining position by means of a second tool (8) which has a second wall (9); placing said second wall in abutment on the reference surface (4) in the machining position; removing said first tool keeping the part (1) in the machining position by means of the second tool (8); machining said second surface of said part. Figure 2

Description

Part machining process

The invention relates to a process for machining a part, as well as a tool for implementing such a process.

It applies in particular to a method in which the part to be machined has an annular geometry and comprises two inner and outer peripheral surfaces to be machined by turning.

The workpiece is, for example, a rolling ring, one peripheral surface of which is intended to form a rolling track for rolling elements, the other surface being intended to be fitted onto a member of a rolling bearing.

To machine the peripheral surfaces to the desired geometry, it is known to support said part by means of a tool for clamping a surface of said part, said surface having undergone prior grinding in order to overcome any deformations of the part, such as those of the ovality type which can be induced by heat treatment of a blank of said part.

In particular, it is known to grind the outer surface prior to its machining in order to be able to clamp said surface by means of outer enveloping jaws with a view to machining the inner surface. This type of process makes it possible to obtain a sufficient radial clamping force for the machining to be carried out, but requires an expensive grinding operation which brings no added value to the machined part insofar as the rectified outer surface will then be machined. .

In addition, the radial clamping can induce a deformation of the part, and the subsequent machining of the outer surface imposes a transfer of tooling including a reversal which can induce coaxial type defects on the machined part.

The invention aims to improve the prior art by proposing in particular a process for machining a part, in particular the outer and inner surfaces of a bearing ring, not requiring prior grinding of the surfaces to be machined, and this while by ensuring optimum clamping and without risk of deformation of said part during said machining, as well as immobilization of said part during the transfer of tools for machining the various surfaces.

To this end, according to a first aspect, the invention proposes a method for machining a part having a first surface, a second surface and a reference surface, said method successively providing for:

• supporting said part by means of a first tool having a first wall;
• immobilize said part in a machining position in which the reference surface of said part abuts against the first wall of said first tool, said first tool being arranged to leave free access to the first surface of said part in said position 'machining;
• machining said first surface of said part;
• supporting said part in the machining position by means of a second tool which has a second wall;
• placing said second wall in abutment on the reference surface in the machining position;
• withdrawing said first tool while keeping the part in the machining position by means of the second tool which is arranged to leave free access to the second surface of said part in said machining position;
• machining said second surface of said part.

According to a second aspect, the invention proposes a tool for the implementation of such a method, said tool comprising a first and a second tool whose first and second abutment walls are angularly discontinuous, said first and second tools being arranged to be able to be arranged angularly with their respective walls positioned in the same abutment plane.

Other objects and advantages of the invention will appear in the following description, made with reference to the appended figures, in which:

is a cross-sectional representation of a tool according to the invention, on which the part is in the machining position of its first surface;

is a representation in cutaway perspective of the tool of figure 1, on which the part is supported by the first and second tool,

And

being enlargements of respectively zone A and zone B of FIG. 2;

is a representation in cutaway perspective of the tooling of FIGS. 1 and 2, on which the part is in the machining position of its second surface.

In relation to the figures, a method for machining a part 1 having a first surface 2, a second surface 3 and a reference surface 4 is described below, as well as a tool for the implementation of such a process.

In the embodiment shown, the workpiece 1 is annular and has an outer axial peripheral surface 2 and an inner axial peripheral surface 3 to be machined by turning.

In addition, the part 1 comprises two radial surfaces 4, 5 extending laterally on either side of the surfaces 2, 3 to be machined, the method providing for the use of one 4 of said lateral surfaces as a reference surface. . To do this, the process provides for prior grinding of the reference surface 4, in order to perfectly define its geometry in order to be able to precisely position the part on the tool during its machining.

In the description, the terms "outside" and "inside" are defined with respect to the axis X of revolution of the workpiece 1 to be machined, respectively for a location distant and close to said axis. Similarly, the terms “axial” and “radial” relate to directions respectively along this axis X and perpendicular to this axis X.

In particular, the part 1 to be machined is a rolling ring, one peripheral surface 2, 3 of which is intended to form a rolling track for rolling bodies, the other peripheral surface 2, 3 being intended to be fitted onto a member of a rolling bearing, or a device peripheral to said bearing.

In the embodiment shown, the method provides for machining the outer peripheral surface 2 first, then the inner peripheral surface 3. Alternatively, the method can provide for machining the inner peripheral surface 3 first and the second surface. outer device 2.

In relation to FIG. 1, the method successively provides for:

• support the part 1 by means of a first tool 6 having a first wall 7;
• immobilize said part in a machining position in which the reference surface 4 of said part is in abutment against the first wall 7 of said first tool, said first tool being arranged to leave free access to the outer peripheral surface 2 in said position machining;
• machining said outer peripheral surface.

After having carried out this first machining, the process then provides for:

• support the part 1 in said machining position by means of a second tool 8 which has a second wall 9, then place said second wall in abutment on the reference surface 4 in the machining position (FIGS. 2, 2a , 2b);
• remove the first tool 6 keeping the part 1 in the machining position by means of the second tool 8, which is arranged to leave free access to the inner peripheral surface 3 of said part in the machining position (figure 3);
• machine the inner peripheral surface 3.

In particular, between the two machining steps of its peripheral surfaces 2, 3 (FIG. 2), the part 1 is secured both to the first tool 6 and to the second tool 8, which makes it possible to keep it immobilized in a position identical machining for each of said steps. Thus, the method makes it possible to avoid movements of the part 1, and therefore to guarantee good coaxiality between the machined surfaces 2, 3.

During the machining of the first surface 2, the method provides for the workpiece 1 to be picked up by the first tool 6 at the level of its second surface to be machined, which corresponds to the inner peripheral surface 3 in the embodiment shown. .

To do this, the first tool 6 has a shaft 10 of substantially cylindrical geometry, on the outer periphery of which is formed an axial wall 11 for supporting the inner peripheral surface 3.

Similarly, during the machining of the second surface 3, the method provides for the part 1 to be picked up by the second tool 8 at the level of its first surface, that is to say the outer peripheral surface 2, the second tool 8 having for this purpose an axial wall 12 adapted.

In particular, the second tool 8 has a barrel 13 of substantially cylindrical geometry, said barrel comprising a bore which is delimited by an inner wall 14, an axial wall 12 supporting the first surface 2 being formed on said inner wall.

In order to be able to bring the reference surface 4 into abutment simultaneously on the first 7 and second 9 walls, said walls are angularly discontinuous, the first 6 and second 8 tools being arranged to be able to be arranged angularly with their respective walls 7, 9 positioned in a same abutment plane against said reference surface.

In the embodiment shown, the first 6 and second 8 tools each comprise radial slots 15, 16 respectively defining the first 7 and the second 9 abutment wall, said slots respectively bordering the axial wall 11 supporting the surface inner peripheral 3 and the axial wall 12 supporting the outer peripheral surface 2.

In particular, as shown in Figure 2, the slots 15 of the first tool 6 are arranged to fit between the slots 16 of the second tool 8, in order to form a substantially continuous abutment wall for the reference surface 4.

To immobilize the part 1 in the machining position, the method provides a third tool 17 for clamping the part 1 in the machining position with its reference surface 4 in abutment on the first 7 and/or second 9 walls respectively.

To do this, the tool comprises a third tool 17 on which the first 6 and second 8 tools can be assembled independently by clamping the part 1 between said third tool and said first and second tools.

In the embodiment shown, the method successively provides:

• an assembly of the first 6 and third 17 tools to immobilize the part 1 between them in the machining position (figure 1);
• after machining of the outer peripheral surface 2, an assembly of the second tool 8 to the third tool 17 to arrange the second wall 9 in abutment on the reference surface 4 in the machining position
  (Figures 2, 2a, 2b), the first 6 and second 8 tools being thus assembled via the third tool 17; And
• disassembly of the first tool 6 in order to be able to machine the inner peripheral surface 3 (FIG. 3).

Thus, the method makes it possible to facilitate the change of tool 6, 8, and in particular to guarantee immobilization of the part 1 in the same machining position for each of its surfaces 2, 3.

In relation to the figures, the shaft 10 of the first tool 6 has a central bore 18 in which is engaged a means 19 for assembly with the third tool 17, in particular in the form of a screw.

In particular, the third tool 17 comprises a housing 20 which has:

• a substantially radial bottom 21, at the center of which opens a bore 22 for receiving the screw 19 for assembling the first tool 6;
• an inner axial wall 23 bordering said bottom, facing which is arranged the outer periphery of the barrel 10 during assembly of the tools 6, 17, the axial wall 11 supporting the second surface 3 and the radial slots 15 being disposed outside said housing.

Advantageously, the bottom 21 of the third tool 17 has a central recess 24 arranged to receive a projection 25 of complementary geometry formed on the first tool 6, in order to facilitate the assembly of said first tool to said third tool 17.

Similarly, the second tool 8 has a flange 26 which extends radially from the outer periphery of the shaft 13 and opposite the axial wall 12 supporting the first surface 2 and the radial slots 16, said flange being arranged to allow the assembly of said second tool to the third tool 17.

To do this, the third tool 17 comprises a flange 27 which extends radially around the assembly housing 20 of the first tool 6 and which is provided with a fixing device, in particular orifices 28, for maintaining the flange 26 of the second tool 8, in particular by means of screws 29.

To allow the immobilization of the part 1 in the machining position, the method provides for a support of the third tool 17 on a surface of the part 1 which is opposite to the reference surface 4, in particular on the side surface 5 s extending radially on the side opposite to said reference surface, said surface advantageously possibly having been previously ground, in particular to ensure parallelism and flatness with the reference surface 4.

To do this, the third tool 17 has a surface 30 for clamping the part 1 on the first 7 and second 9 abutment walls, said clamping surface extending axially around the housing 20, in particular in the axial extension of the wall interior 23.

Thus, the method provides for immobilizing the part 1 in the machining position by axial clamping, which makes it possible to avoid radial forces, and therefore to limit the risks of deformation of said part during said clamping guaranteeing the circularities and concentricities respective first 1 and second 2 surfaces. Furthermore, this arrangement makes it possible to exert a significant clamping force on the part 1, and therefore to guarantee its proper immobilization during machining.

Claims (15)

Method of machining a part (1) having a first surface (2), a second surface (3) and a reference surface (4), said method successively providing for:

• supporting said piece by means of a first tool (6) having a first wall (7);
• immobilizing said part in a machining position in which the reference surface (4) of said part is in abutment against the first wall (7) of said first tool, said first tool being arranged to allow free access to the first surface ( 2) of said part in said machining position;
• machining said first surface of said part;
• supporting said part in the machining position by means of a second tool (8) which has a second wall (9);
• disposing said second wall in abutment on the reference surface (4) in the machining position;
• removing said first tool keeping the part (1) in the machining position by means of the second tool (8) which is arranged to leave free access to the second surface (3) of said part in said machining position;
• machining said second surface of said part.

Machining method according to Claim 1, characterized in that it provides for a pick-up of the workpiece (1) at its first (2) – respectively its second (3) – surface by the second (8) – respectively the first (6) – tool. Machining method according to one of Claims 1 or 2, characterized in that it provides peripheral pick-up of the part (1) by one and/or the other of the tools (6, 8), said piece being annular, having an outer peripheral surface (2) and an inner peripheral surface (3) to be machined. Machining method according to any one of Claims 1 to 3, characterized in that it provides for prior grinding of the reference surface (4). Machining method according to any one of Claims 1 to 4, characterized in that it provides for the use of a lateral surface (4) of the part (1) as a reference surface. Machining method according to any one of Claims 1 to 5, characterized in that it provides a third tool (17) for clamping the part (1) in the machining position with its reference surface (4) in abutment on respectively the first (7) and/or second (9) walls. Machining method according to claim 6, characterized in that it provides for the third tool (17) to rest on a surface (5) of the workpiece (1) which is opposite the reference surface (4). Machining method according to claim 7, characterized in that it provides for prior grinding of the opposite surface (5). Machining method according to any one of Claims 6 to 8, characterized in that it provides successively:

• an assembly of the first (6) and third (17) tools to immobilize the part (1) between them in the machining position;
• after machining the first surface (2), an assembly of the second tool (8) to the third tool (17) to arrange the second wall (9) in abutment on the reference surface (4) in the machining position;
• disassembly of the first tool (6) in order to be able to machine the second surface (3).

Machining method according to any one of Claims 1 to 9, characterized in that the part (1) to be machined is a rolling ring. Tooling for implementing a machining process according to any one of Claims 1 to 10, characterized in that it comprises a first (6) and a second (8) tool whose first (7) and second (9) abutment walls are angularly discontinuous, said first and second tools being arranged to be able to be arranged angularly with their respective walls (7, 9) positioned in the same abutment plane. Tool according to Claim 11, characterized in that the first (6) – respectively the second (8) – tool has an axial wall (11, 12) supporting the second (3) – respectively the first (2) - surface of the part (1), said axial walls being bordered by radial slots (15, 16) defining the abutment wall (7, 9). Tool according to Claim 12, characterized in that the notches (15) of the first tool (6) are arranged to fit between the notches (16) of the second tool (8). Tool according to any one of Claims 11 to 13, characterized in that it comprises a third tool (17) on which the first (6) and second (8) tools can be assembled independently by clamping the part (1) between said third tool and said first and second tools. Tool according to Claim 14, characterized in that the third tool (17) has a surface (30) for clamping the workpiece (1) on the abutment walls (7, 9) of the first (6) and second (8) tools.