Brake disc tool for machining a brake disc blank, brake disc production plant and method for producing a brake disc

Abstract

A brake disc tool for machining a brake disc blank is provided. The brake disc tool includes a first cutting tool which is arranged to cut a first brake surface of the brake disc blank, a second cutting tool which is arranged to cut a second brake surface of the brake disc blank, a first forming tool for forming the first brake surface, a second forming tool for forming the second brake surface, and at least one infeed device for the infeed of the cutting tools and the forming tools towards one another, such that a brake disc blank arranged between the cutting tools and the forming tools is able to be machined and rolled in each case simultaneously on both of its brake surfaces.

Claims

1. A method for producing a brake disc by rotating a brake disc blank about a rotational axis by means of a brake disc rotation device of a machine tool, wherein the rotational axis is the same axis about which a brake disc rotates during operation, comprising: (i) engaging a first cutting tool of a brake disc tool at a first cutting point of engagement which is at a first cutting distance from the rotational axis, so that the first cutting tool cuts a first brake surface of the brake disc blank; (ii) engaging a second cutting tool of the brake disc tool at a second cutting point of engagement which is at a second cutting distance from the rotational axis, so that the second cutting tool cuts a second brake surface of the brake disc blank; (iii) engaging a first forming tool of the brake disc tool at a first forming point of engagement which is at a first forming distance from the rotational axis, so that the first brake surface is formed; (iv) engaging a second forming tool of the brake disc tool at a second forming point of engagement which is at a second forming distance from the rotational axis, so that the second brake surface is formed, wherein the first cutting point of engagement and the first forming point of engagement form an angle with the rotational axis, this angle having an angle bisector; and (v) moving the first and second cutting tools and the first and second forming tools such that, at least when all tools are engaged, a first difference in distance between a projection of the first cutting point of engagement onto the bisector and a projection of the first forming point of engagement onto the bisector or a second difference in distance between a projection of the second cutting point of engagement onto the bisector and a projection of the second forming point of engagement onto the bisector remains constant and/or does not exceed a radial distance between the first and second brake surfaces and a hub section of the brake disc blank which protrudes axially above a brake surface plane on which the first brake surface lies.

2. The method according to claim 1 further comprising: (i) infeeding of the first and second cutting tools and the first and second forming tools onto the first and second brake surfaces of the brake disc blank, (ii) rotating the brake disc blank, and (iii) simultaneously cutting and forming the first and second brake surfaces.

3. The method according to claim 1 further comprising: (i) infeeding of the first and second cutting tools, followed by (ii) rotating the brake disc blank in a first direction of rotation and the cutting of the brake surfaces, followed by (iii) rotating the brake disc blank in an opposite direction of rotation and simultaneously forming the first and second brake surfaces.

4. The method according to claim 1 further comprising: moving the first and second cutting tools and the first and second forming tools radially inwards to disengage the tools from the cutting and forming points of engagement respectively, engaging the first and second cutting tools and the first and second forming tools at cutting and forming points of engagement respectively that are different from the first and second cutting and forming points of engagement followed by moving the first and second cutting tools and the first and second forming tools radially outwards and simultaneously cutting and forming of the brake surfaces.

5. The method according to claim 1, further comprising: moving the second forming tool and the second cutting tool radially inwards, followed by stopping of the radially inwards movement of the second cutting tool and continuing the radially inwards movement of the second forming tool.

6. The method according to claim 1, further comprising: rotating of the brake disc blank in a first direction of rotation while cutting of the brake surfaces; and rotating the brake disc blank in an opposite direction of rotation while forming the first and second brake surfaces.

7. The method according to claim 1 further comprising: moving the first and second cutting tools radially inwards to disengage the tools from the cutting points of engagement, engaging the first and second forming tools at the forming points of engagement followed by moving the first and second forming tools radially outwards to form the brake surfaces.

8. A method for producing a brake disc by rotating a brake disc blank about a rotational axis by means of a brake disc rotation device of a machine tool, wherein the rotational axis is the same axis about which a brake disc rotates during operation, comprising: engaging a first cutting tool of a brake disc tool at a first cutting point of engagement which is at a first cutting distance from the rotational axis, so that the first cutting tool cuts a first brake surface of the brake disc blank; engaging a second cutting tool of the brake disc tool at a second cutting point of engagement which is at a second cutting distance from the rotational axis, so that the second cutting tool cuts a second brake surface of the brake disc blank; engaging a first forming tool of the brake disc tool at a first forming point of engagement which is at a first forming distance from the rotational axis, so that the first brake surface is formed; engaging a second forming tool of the brake disc tool at a second forming point of engagement which is at a second forming distance from the rotational axis, so that the second brake surface is formed, moving the first forming tool and the first cutting tool radially inwards, followed by stopping of the radially inwards movement of the first cutting tool and continuing the radially inwards movement of the first forming tool.

Description

(1) In the following, the invention will be explained in more detail by way of the attached drawings. They show

(2) FIG. 1 with the partial images 1a-1d, a brake disc tool according to the invention, according to a first embodiment,

(3) FIG. 2 with the partial images 2a-2d, a brake disc tool according to the invention, according to a second embodiment,

(4) FIG. 3 a schematic view of a brake disc production system according to the invention for executing a method according to the invention,

(5) FIG. 4 with the partial images 4a-4f, a brake disc tool according to the invention, according to a third embodiment,

(6) FIG. 5 with the partial images 5a-5f, a brake disc tool according to the invention, according to a fourth embodiment,

(7) FIG. 6 with the partial images 6a-6f, a brake disc tool according to the invention, according to a fifth embodiment,

(8) FIG. 7 with the partial images 7a-7e, a brake disc tool according to the invention, according to a sixth embodiment,

(9) FIG. 8 with the partial images 8a-8b, a brake disc tool according to the invention, according to a seventh embodiment.

(10) Partial image 1a in FIG. 1 shows a brake disc tool 10 according to the invention for machining a brake disc blank 12, thereby producing a brake disc. The brake disc tool 10 features a first cutting tool 14, a second cutting tool 16 (see FIG. 1b), a first forming tool 18 and a second forming tool 20.

(11) The first forming cutting tool 14 comprises an insert, for example made of ceramic, hard metal, coated hard metal, a cermet or cubic boron nitride. The first cutting tool 14 is accommodated in a first tool accommodation 22; the second cutting tool 16 is constructed in the same as the first cutting tool 14 and is fixed to a second tool accommodation 24.

(12) The forming tools 18,20 are designed to be rolling tools and each have rolling elements 26, 28, each of which is accommodated in a guide 30, 32. A pressurized fluid is applied to the forming tools 18, 20 by means of a pressurized fluid source (not shown). The pressurized fluid may refer to a liquid, a gas or an aerosol, in particular a lubricating particle mist.

(13) The cutting tool 14 and the first forming tool 18 are configured to machine a first brake surface 34. The second cutting tool 16 and the second forming tool 20 are configured to machine a second brake surface 36, which runs parallel to the first brake surface 34. The brake disc blank 12 also comprises a hub section 38, which protrudes axially above a brake disc plane E, on which the first brake surface 34 lies. A circumferential groove 40 runs between the hub section 38 and the first brake surface 34.

(14) The brake disc tool 10 has an infeed device 42, by means of which the cutting tools 14, 16 and the forming tools 18, 20 can be fed in towards one another. This renders it possible to precisely set a disc thickness d, i.e. a distance between the first brake surface 34 and the second brake surface 36. In the present case, the infeed device 42 has a cutting tool infeed device 43 for moving the first cutting tool 14 relative to the tool mount 46.

(15) In the present case, the cutting tool infeed device 43 comprises the first tool accommodation 22 and a schematically depicted drive 44 which, for instance, may feature a drive worm and a rotary drive. The first tool accommodation 22 is linearly guided on a tool mount 46 in the axial direction in relation to a rotational axis R of the brake disc blank 12. The first tool accommodation 22 can thus be moved relative to the tool mount 46 by means of the drive 44.

(16) According to a preferred embodiment, the second tool accommodation 24 and the forming tools 18, 20 are also linearly guided by the tool mount 46 and can be moved relative to it. In the present embodiment, the infeed device 42 comprises a forming tool infeed device 45 for moving the first forming tool 18 relative to the tool mount 46 (see FIG. 1b). The forming tool infeed device 45 is constructed in the same way as the cutting tool infeed device 43 and has a drive 47. In FIG. 1b, the drive 44 is not depicted for the sake of clarity.

(17) However, it is also possible that one drive moves both tool accommodations 22, 24 and another drive moves both forming tools 18, 20. It is also possible that both cutting tools 14, 16 and both forming tools 18, 20 are designed such that they can be moved relative to the tool mount 46 by means of a motor. In this case, it is not necessary for the tool mount 46 to be designed so that it can be moved relative to the brake disc blank 12.

(18) The drive 44 and the additional drives, if present, may comprise an electric motor or be driven hydraulically. The drive 44 and the other available drives, if present, may also comprise at least one hydraulic expansion cushion and a pressurized fluid supply connected to said cushion, which move the respective tool either towards or away from the brake disc blank 12 upon an increase in fluid pressure in the hydraulic expansion cushion.

(19) In the present case, the tool mount is fixed to a linear guide 48 and can thus be moved in a direction that is perpendicular to a rotational axis R.

(20) FIG. 1c shows a view of the brake disc tool 10 from the front.

(21) FIG. 1d shows that in the present case, the cutting tools 14, 16 (see FIG. 1c) and the forming tools 18, 20 are mounted by means of the tool mount 46 and the linear guide 48 in such a way that the first cutting tool 14 moves along a cutting tool line g.sub.Z. The first forming tool 18 moves along a forming tool line g.sub.U. The cutting tool line g.sub.Z intersects the rotational axis R. However, it is also possible that it is at a small distance, different from zero, from the rotational axis R, which is for instance smaller than one fiftieth of an outer diameter D of the brake disc blank 12. The forming tool line g.sub.U runs parallel to the cutting tool line g.sub.Z.

(22) According to an alternative method according to the invention, it is possible that the tools 14, 16, 18, 20 are disengaged by way of a radially inwards movement. The cutting tools 14, 16 then engage with the radially inward edge of the brake surfaces 34, 36 and are moved radially outwards. The forming tools 16, 18 also engage. This means that the brake surfaces 34, 36 are simultaneously cut and formed while the tools 14, 16, 18, 20 move radially outwards.

(23) FIG. 2 shows a second embodiment of a brake disc tool 10 according to the invention. FIG. 2d shows that, unlike the embodiment according to FIG. 1, the lines g.sub.Z and g.sub.U are at the same distance from the rotational axis R and thus from a separating plane T on which the rotational axis runs. The first cutting tool 14 and the rolling element 16 can therefore be arranged at the same or essentially the same radial distance from the rotational axis R.

(24) In other words, the first cutting tool 14 comes into contact with the brake surface 34 at a first cutting point of engagement P.sub.14 and the first forming tool 18 at a first forming point of engagement P.sub.26.

(25) A difference in distance Δr, which indicates the difference of the radial distances of the points P.sub.14 and P.sub.26 from the rotational axis R, is small. In particular, the difference in distance Δr is smaller than a groove width n. Groove width is the radial distance between the first brake surface 34 and the hub section 38 (see FIG. 2b). The difference in distance Δr is preferably smaller than 0.8-times the groove width n.

(26) The second cutting tool 16, when at a second cutting point of engagement P.sub.16 (FIG. 2c), lies flat on the second brake surface 36 and the rolling element 28 of the second forming tool 20, when at a second forming point of engagement P.sub.28, lies flat on the second brake surface 36. The radial distance of the point P.sub.16 from the rotational axis R corresponds to the radial distance of the point P.sub.14. The radial distance of the point P.sub.28 corresponds to the radial distance of the point P.sub.26.

(27) FIG. 3 schematically depicts a brake disc production system 50 according to the invention, this system comprising a brake disc tool 10 and a machine tool 52, by means of which the brake disc tool 10 can be positioned relative to a brake disc rotation device 54. The brake disc rotation device 54 is designed to accommodate the brake disc blank 12, for example at its hub section 38. A stamp 56 that can be fed in may also be provided, which for example catches in the hub section 38 by way of holes.

(28) A method according to the invention is executed, for example, by the brake disc blank 12 first of all being accommodated on the brake disc rotation device 54. It is then rotated in a direction of rotation ω.sub.1. The cutting tools 14, 16 are fed in onto the brake surfaces 34, 36, either individually or collectively, until the distance between the two corresponds to a predetermined disc thickness d. The cutting tools 14, 16 are then moved in the radial direction along the line g.sub.Z and cut the brake surfaces 34, 36.

(29) The cutting tools 14, 16 then disengage. The forming tools 18, 20 are also fed in so far onto the machined brake surfaces 34, 36 that the respective rolling elements 26, 28 come into contact with the brake surfaces 34, 36 and form them. It is possible, but not necessary, for the rotation speed during forming to be the same as during cutting. For instance, it is possible that cutting is conducted at a higher speed than forming.

(30) A predetermined rolling pressure is applied to the rolling elements 26, 28 and the forming tools 18, 20 are guided on the brake surfaces 34, 36 in the radial direction, such that they are deep and/or flat-rolled. Following this machining, the brake disc blank 12 has become a brake disc. It is possible that this is followed by further machining steps.

(31) FIG. 4a shows a third embodiment of a brake disc tool 10 according to the invention for cutting in the form of rotational machining and simultaneously forming in the form of a rolling process. During machining, the cutting tools 14, 16 (see FIG. 4d) move on the respective cutting tool lines g.sub.Z, which run through the rotational axis R. To this end, the cutting tools 14, 16 are guided linearly, as described above.

(32) The first forming tool 18 is mounted relative to the first cutting tool 14 such that it is linearly guided. To this end, a linear axis 58 is configured between the first tool accommodation 22 and the first forming tool 18, wherein this axis can also be described as a linear guide. A motor of the linear axis 58 is depicted. FIGS. 4a and 4b depict the linear axis 58 in a first position, partial FIG. 4c depicts the linear axis 58 in a second position, in which the first forming tool 18 with a radial component is at a linear offset relative to the first tool accommodation 22.

(33) The second forming tool 20, part of which is visible in FIG. 4d, is fixed to a forming tool mount 60 in the same way as the first forming tool 18; this forming tool mount forms the linear axis 58 with the tool mount 46 to which the tool accommodations 22, 24 are fixed. In the present case, the linear axis 58 comprises a dovetail guide and a schematically depicted motor for moving the tool mount 46 relative to the forming tool mount 60. This results in the second forming 20 also being linearly guided relative to the second cutting tool 16. The tool mount or the forming tool mount 60 are fixed to a machine 61, which is partially schematically depicted.

(34) FIGS. 4a, 4b and 4c schematically depict the order of a method according to the invention. First of all, the forming tools 18, 20 and the cutting tools 14, 16 are moved radially inwards with the same radial movement component. The radial movement component is determined by the projection of the corresponding movement vector on the cutting tool line g.sub.Z. If the state shown in FIG. 4b is achieved, in which the cutting tools 14, 16 have completely cut the brake surfaces 34, 36 (see FIG. 4e), the radially inwards movement of the cutting tools 14, 16 is stopped. The forming tools 18, 20 continue to move relatively inwards, i.e. in the feed direction, until the two brake surfaces 34, 36 have been fully rolled. All tools 14, 16, 18, 20 then disengage and the brake disc tool is moved radially outwards.

(35) FIG. 5 shows another embodiment of a brake disc tool according to the invention. With this embodiment, the cutting tool line g.sub.Z and the forming tool line g.sub.U confine a spread angle σ, which is different to zero. In the present case, the lines g.sub.Z, g.sub.U run through the rotational axis R, which represents a preferred, but not necessary, embodiment.

(36) Both the tool accommodations 22, 24 (see FIG. 5b) and the forming tools 18, 20 (see FIG. 5c) are guided linearly on the tool mount 46 and are moved either simultaneously or consecutively. FIGS. 5a and 5b on the one hand and 5d and 5e on the other depict the order of a method according to the invention. At the beginning of the method, the tools 14, 16, 18, 20 are in a radially outwards position. During the method, they are moved radially inwards and the brake surfaces are machined 34, 36. Following machining, the tools disengage and are driven back, moving radially outwards. The tool mount 46 does not move during this process.

(37) FIG. 6 depicts a fifth embodiment of a brake disc tool 10 according to the invention whereby the cutting line g.sub.Z and the forming line g.sub.U also run through the rotational axis R. Unlike the embodiment according to FIG. 5b, the tool mount 46 is linearly guided on the machine tool 61 such that it is moveable, so it can be moved during a method according to the invention.

(38) The invention also envisages a machine tool that comprises a brake disc tool according to the invention. The tool mount 46 is preferably automatically linearly guided in this machine tool such that it can be moved.

(39) FIG. 7 shows a brake disc tool 10 according to the invention, all tools 14, 16, 20 of which are arranged in such a way that they can each be moved automatically relative to the tool mount 46. The tool mount 46 is guided, for example linearly, on the machine tool. As FIGS. 7c and 7d show, it is possible to engage and disengage all tools 14, 16, 18, 20 with/from the brake disc blank 12 independently of the respective other tools. In other words, the cutting tools 14, 16 are connected to the tool mount 46 such that a joint infeed movement can occur. The rolling elements 26, 28 can also be moved relative to the cutting tools 14, 16. This type of mounting of the tools 14, 16, 18, 20 is also possible for all other embodiments.

(40) FIG. 8 shows a brake disc tool 10 according to the invention which comprises a vibration damping device 62, which is pressed against the first brake surface 34, for instance by means of compressed air or a pressure fluid. Vibrations lead to an oscillation of the vibration damping device 62, which is dampened by the internal friction of the pressurized fluid (compressed air or pressure fluid) or by the flow of the pressurized fluid through a nozzle. In general, the forming tools are preferably dampened to such a strong extent that an additional vibration damping device 62 is not necessary.

(41) TABLE-US-00001 Reference list 10 brake disc tool 12 brake disc blank 14 first cutting tool 16 second cutting tool 18 first forming tool 20 second forming tool 22 first tool accommodation 24 second tool accommodation 26 rolling element 28 rolling element 30 guide 32 guide 34 first brake surface 36 second brake surface 38 hub section 40 groove 42 infeed device 43 cutting tool infeed device 44 drive 45 forming tool infeed device 46 tool mount 48 linear guide 50 brake disc production system 52 machine tool 54 brake disc rotation device 56 stamp 58 linear axis 60 forming tool mount 61 machine tool 62 vibration damping device E brake surface place d disc thickness D outer diameter g.sub.Z cutting tool line g.sub.U forming tool line T separating plane n groove width P point of engagement R rotational axis Δr difference in distance ω direction of rotation σ spread angle