Broaching tool, broaching machine comprising such a tool and method for machining a workpiece using such a machine

Abstract

A broaching tool includes at least one cutting zone with a cutting face that contacts a workpiece to remove material from the workpiece. At least one cavity corresponds to the cutting zone and is arranged to receive the removed material. A plurality of lubrication channels are supplied with lubricant, each lubrication channel having an inlet opening arranged to receive the lubricant and at least one outlet opening which opens into the cavity. The distance between the outlet openings of two consecutive lubrication channels varies further from the cutting face.

Claims

1. A broaching tool, comprising: at least one cutting area comprising a cutting face configured to come into contact with a workpiece to remove material, in the shape of at least one chip, from said workpiece, at least one cavity corresponding to said cutting area, said cavity being arranged to receive said at least one chip, at least three lubrication channels associated with the or each cavity and configured to be supplied with lubricant, each lubrication channel having an inlet orifice arranged to receive the lubricant and at least one outlet orifice opening into said cavity, wherein a distance between the outlet orifices of two consecutive lubrication channels of the at least three lubrication channels increases by moving away from the cutting face.

2. The broaching tool according to claim 1, wherein the lubrication channels are inclined relative to the cutting face.

3. The broaching tool according to claim 1, wherein the inlet orifices are aligned.

4. The broaching tool according to claim 1, further comprising a plurality of cutting areas, each cutting area comprising a cutting face configured to come into contact with the workpiece to remove material from said workpiece, and a plurality of cavities configured to receive said material, one cavity being arranged between two successive cutting areas, and wherein, in each cavity open out the outlet orifices of the lubrication channels configured to be supplied with lubricant, each lubrication channel having an inlet orifice arranged to receive the lubricant.

5. A broaching machine, comprising: the broaching tool according to claim 4, a lubrication system comprising a lubricant tank and lubrication means configured to deliver lubricant from said tank to the outlet orifices of the lubrication channels under high pressure of between 10 and 300 bar, and a frame, the broaching tool being mobile in translation relative to the frame, the lubrication system being fixed in translation relative to the frame and in which the lubrication means comprise a lubrication distributor configured to supply lubricant under high pressure to the lubrication channels of at least one or of each cavity corresponding to a cutting area, a cutting face of which comes into contact with the workpiece.

6. The broaching machine according to claim 5, wherein the lubrication distributor comprises at least one seal.

7. A broaching machine, comprising: the broaching tool according to claim 4, a lubrication system comprising a lubricant tank and lubrication means configured to deliver lubricant from said tank to the outlet orifices of the lubrication channels under high pressure of between 10 and 300 bar, and a frame, the broaching tool being fixed in translation relative to the frame, the lubrication system being mobile in translation relative to the frame and in which the lubrication means comprise a lubrication distributor configured to supply lubricant under high pressure to the lubrication channels of at least one or of each cavity corresponding to a cutting area, a cutting face of which comes into contact with the workpiece.

8. The broaching machine according to claim 7, wherein the lubrication distributor comprises at least one seal.

9. A broaching machine, comprising: the broaching tool according to claim 1, and a lubrication system comprising a lubricant tank and lubrication means configured to deliver lubricant from said tank to the outlet orifices of the lubrication channels under high pressure of between 10 and 300 bar.

10. A method for machining a workpiece by means of a broaching machine according to claim 9, the broaching machine comprising a frame, one of the broaching tool and said workpiece being fixed relative to the frame, the method comprising the steps of: translating the other of the broaching tool and the workpiece relative to the frame so that at least one cutting face comes into contact with the workpiece, lubricating, by means of the lubrication system, the at least one cavity corresponding to the cutting area for which the cutting face comes into contact with the workpiece, stopping the lubrication of the at least one cavity corresponding to said cutting area as soon as the cutting face ceases to be in contact with the workpiece.

Description

DESCRIPTION OF THE DRAWINGS

(1) The disclosure will be better understood and other details, characteristics and advantages of the present disclosure will become clearer from the following description made by way of non-limiting example and with reference to the attached drawings, in which:

(2) FIG. 1 is a cross-sectional view of the principle of the chip removal machining;

(3) FIG. 2 is a cross-sectional view of the principle of a broaching operation;

(4) FIG. 3 is a perspective view of a broaching tool according to the disclosure;

(5) FIG. 4 is a cross-sectional view of a broaching tool according to the disclosure;

(6) FIG. 5 is a cross-sectional view of a broaching machine according to the disclosure;

(7) FIG. 6 is a cross-sectional view of the broaching machine of FIG. 5; and

(8) FIG. 7 shows an enlarged view of the box B in FIG. 6.

(9) The elements having the same functions in the different implementations have the same references in the figures.

DETAILED DESCRIPTION

(10) FIGS. 3 and 4 show a broaching tool 20 according to the disclosure.

(11) The broaching tool 20 comprises a plurality of cutting areas 22, in this case three cutting areas. Each cutting area 22 comprises a cutting face 24 intended to come into contact with a workpiece to be broached so as to remove material, in the form of at least one chip, from the workpiece. The cutting face 24 is a surface of the cutting area 22, between an undercut area 25, also called an undercut face, and a cavity 26. A cutting face 24 may be a surface of any shape, or a flat surface as in FIGS. 3 and 4.

(12) Similarly, an undercut face 25 may be a surface of any shape, or a flat surface as in FIGS. 3 and 4.

(13) A cutting edge 27 is defined as an intersection between a cutting face 24 and an undercut area 25.

(14) In FIG. 4, the cutting faces 24 are not staged. Although not shown, the cutting faces 24 may be staged.

(15) The broaching tool 20 comprises a plurality of cavities 26, each cavity 26 corresponding to a cutting area 22. A cavity 26 is arranged so as to receive the material that a cutting face 24a removes from the workpiece to be broached. Thus, a cavity is associated with a cutting face 24, and thus with a cutting area 22. A cavity is arranged between two consecutive cutting areas 22. In a cross-sectional view, for example as shown in FIG. 4, a cavity 26 has a general U shape. Of course, the cavity may have any other cross-sectional shape, such as a general V shape or any other shape.

(16) The broaching tool 20 also comprises a plurality of lubrication channels 28 intended to be supplied with lubricant, each lubrication channel 28 having an inlet orifice 30 arranged to receive lubricant and an outlet orifice 32 opening into a cavity 26.

(17) In FIG. 3, there is one lubrication channel 28 per cavity 26. However, the broaching tool 20 may comprise a plurality of lubrication channels 28 per cavity 26. In particular, the broaching tool 20 may comprise between one and thirty lubrication channels 28 per cavity 26. In FIG. 4, there are four lubrication channels 28a, 28b, 28c, 28d for the cavity 26.

(18) Although not shown, a lubrication channel 28 may comprise a single inlet orifice 30 and a plurality of outlet orifices 32, each outlet orifice 32 opening into a cavity 26. In other words, a lubrication channel 28 may be divided into sub-lubrication channels, each sub-lubrication channel having an outlet orifice 32 opening into a cavity 26.

(19) As shown in FIG. 4, the outlet orifices 32 of the lubrication channels 28 are distributed over the surface of a cavity 26.

(20) In particular, the outlet orifices 32 of the lubrication channels 28 may be evenly distributed over the surface of the cavity.

(21) Alternatively, the distance between the outlet orifices 32 of two consecutive lubrication channels 28 may vary by moving away from the cutting face 24. As shown in FIG. 4, the distance between the outlet orifices 32 of two consecutive lubrication channels 28 may increase by moving away from the cutting face 24. Indeed, the distance between the orifice 32 of the lubrication channel 28a and the orifice 32 of the lubrication channel 28b is smaller than the distance between the orifice 32 of the lubrication channel 28b and the orifice 32 of the lubrication channel 28c. Similarly, the distance between the orifice 32 of the lubrication channel 28c and the orifice 32 of the lubrication channel 28d is greater than the distance between the orifice 32 of the lubrication channel 28b and the orifice 32 of the lubrication channel 28c. Thus, the spacing between two outlet orifices 32 of two consecutive lubrication channels 28 decreases by moving closer to the cutting face 24.

(22) Alternatively, although not shown, the distance between the outlet orifices 32 of two consecutive lubrication channels 28 may increase as one moves closer to the cutting face 24. Thus, the spacing between two outlet orifices 32 of two consecutive lubrication channels 28 decreases by moving away from the cutting face 24.

(23) The distance between the inlet orifices 30 of the lubrication channels 28 may be identical. Alternatively, the distance between the inlet orifices 30 of the consecutive lubrication channels 28 may vary.

(24) The cutting face 24 extends along an axis, noted A1 in FIG. 4. At least one lubrication channel 28 may extend along another axis, which is different from the axis A1. As shown in FIG. 4, in the plane (A1, B2), the lubrication channel 28a extends substantially along the axis A1, the lubrication channel 28b extends along an axis A2 that forms an angle 2 with the axis A1, the lubrication channel 28c extends along an axis A3 that forms an angle 3 with the axis A1, and the lubrication channel 28d extends along an axis A4 that forms an angle 4 with the axis A1. In the plane (A1, B2), the angles 1, 2 and 3 may be between 0 and 90, and preferably between 0 and 60.

(25) The lubrication channels may extend along axes not included in the plane (A1, B2), for example in a plane defined by an axis parallel to the axis A1 and an axis parallel to the axis B2 and define solid angles in these planes. The solid angles 1, 2 and 3 can be between 0 and 90. Preferably, the solid angles 1, 2 and 3 are between 0 and 60.

(26) As shown in FIG. 3, the inlet orifices 30 of the lubrication channels 28 may be aligned.

(27) For example, the inlet orifices 30 may be aligned in the direction of elongation of the broaching tool 20, represented by the axis B1 in FIG. 3.

(28) Similarly, the outlet orifices 32 of the lubrication channels 28 may be aligned. For example, the outlet orifices 32 may be aligned in the direction of elongation of the broaching tool 20, represented by the axis B2 in FIG. 3.

(29) A lubrication channel 28 may be straight and extend along an axis. For example, the lubrication channels 28a, 28b and 28c are straight and extend along the axes A1, A2 and A3 respectively.

(30) Alternatively, a lubrication channel 28 may have an elbow shape and comprise straight portions. For example, the lubrication channel 28d has an elbow shape, and comprises two straight portions, the second straight portion extending along the axis A4.

(31) The length of a lubrication channel 28, i.e. the longitudinal size of a lubrication channel, may be different from the length of another lubrication channel 28. For example, in FIG. 4, the lubrication channels 28a, 28b, 28c, 28d have different lengths. These differences in the length of the lubrication channels result in differences in the height of the outlet orifices 32. Thus, the outlet orifices 32 may not be aligned along an axis orthogonal to the direction of elongation of the broaching tool 20.

(32) The cross-section of a lubrication channel 28 may be circular, oval, polygonal, or any shape.

(33) The cross-section of an inlet orifice 30 of a lubrication channel 28 may be circular, as shown in FIG. 3, or oval, or polygonal, or any shape. Similarly, the cross-section of an outlet orifice 32 of a lubrication channel 28 may be circular, as in FIG. 3, or oval, or polygonal, or any shape.

(34) In particular, the number of outlet orifices 32, the position of the lubrication channels 28 on the cavity 26, as well as their inclination relative to the axis A1 of the cutting edge 24 depends on the size and the shape of the cutting edge 24.

(35) FIGS. 5 to 7 show a broaching machine according to the disclosure.

(36) The broaching machine 40 comprises a frame. The workpiece 1 to be broached can be arranged fixed relative to the frame. Alternatively, the workpiece to be broached can be arranged mobile in translation relative to the frame.

(37) The broaching machine 40 also comprises the broaching tool 20, which may be arranged mobile in translation relative to the frame, the translation movement of the broaching tool 20 being represented by the arrow A. The broaching tool 20 may be arranged on a slider 42, which is mobile in translation relative to the frame. Alternatively, the broaching tool 20 may be fixed relative to the frame.

(38) The broaching machine 40 also comprises a lubrication system 41, which is fixed in translation with respect to the workpiece. The lubrication system 41 comprises a tank 43 of lubricant and lubrication means 45 configured to deliver the lubricant from the tank 43 to at least one outlet orifice 32 of a lubrication channel 28 under high pressure. The lubrication system 41 allows the lubricant to be delivered at a pressure of between 10 and 300 bar.

(39) The lubrication means 45 may comprise a lubrication distributor 44 configured to supply lubricant under high pressure to the or each lubrication channel 28 of one or of each cavity 26 corresponding to a cutting area 22 having a cutting edge 24 in contact with the workpiece 1. In particular, the lubrication distributor 44 supplies lubricant only to the lubrication channels 28 of the cavities 26 corresponding to the cutting areas 22 whose cutting edges 24 are in contact with the workpiece 1 or are about to come into contact with the workpiece 1. In other words, the lubrication distributor 44 supplies lubricant only to the lubrication channels 28 for which the cavities 26 correspond to the cutting edges 24 engaged or about to engage in the workpiece 1. For example, in FIG. 5, three cutting edges 24a, 24b, 24c are in contact with the workpiece 1 so as to form a chip 5, the corresponding cavities 26a, 26b, 26c are then lubricated through the lubrication channels 28. The lubrication of the cutting areas is shown by the dotted line 34. The lubrication channels 28 in FIG. 5 are not supplied with lubricant. Thus, the supply to the lubrication channels 28 ceases as soon as the cutting edge 24 to which a cavity 26 corresponds is no longer in the workpiece 1.

(40) Thus, during the broaching, the lubrication distributor 44 allows the selective supply of the lubrication channels 28, 28 to deliver the lubricant from the tank 43 at the level of the cutting area of a broaching tool 20.

(41) The lubrication distributor 44 may comprise one or a plurality of seals 46 allowing to ensure the sealing of the interface of the lubrication distributor 44 with the broaching tool 20. In FIGS. 6 and 7, a lubrication channel 28, shown in dotted line in FIG. 6, is supplied with lubricant from the tank 43, with the arrow L in FIG. 7 representing the supply of lubricant through the lubrication distributor 44.

(42) A method for machining a workpiece 1 by means of a broaching machine 40 as previously described comprises a step of translating one of the broaching tool 20 and the workpiece 1 relative to the frame, the other of the broaching tool 20 and the workpiece 1 being fixed relative to the frame, so that at least one cutting edge 24a, 24b, 24c comes into contact with the workpiece 1.

(43) The method also comprises a step of lubricating the or each cavity 26 corresponding to a cutting area where the cutting edge 24a, 24b, 24c enters into contact with the workpiece 1, by means of the lubrication system 41.

(44) The method also comprises a step of stopping the lubrication of the or each cavity corresponding to the cutting area as soon as the cutting edge 24a, 24b, 24c ceases to be in contact with the workpiece 1.

(45) In particular, the lubrication can be carried out by means of a liquid lubricant, such as a whole oil, or an emulsion.

(46) The size of the lubrication distributor 44 are based on the size of the workpiece 1 to be broached, so that lubrication is carried out only for the cutting areas 22 whose cutting edges 24 are in contact with the workpiece 1.