WO2000072994A2

WO2000072994A2 - Method and device for flow turning

Info

Publication number: WO2000072994A2
Application number: PCT/EP2000/004636
Authority: WO
Inventors: Günter POLLKÖTTER
Original assignee: Leico Gmbh & Co. Werkzeugmaschinenbau
Priority date: 1999-05-26
Filing date: 2000-05-22
Publication date: 2000-12-07
Also published as: EP1181119B1; EP1181119A2; WO2000072994A3; DE19924062A1; DE50004428D1

Abstract

The invention relates to a method and a device for producing vehicle wheels having a rim consisting of a steel material. A tubular element having uniform wall thickness is used as work piece and clamped in a flow turning machine. At least one profiling roller is radially advanced by means of which the work piece is radially drawn in and a rim profile is formed. In order to reduce the mass of the rim, the work piece is clamped in a cylindrical rolling arbor before the rim profile is formed, the diameter of said arbor corresponding to the inner diameter of the tubular element. The wall thickness is reduced in a defined manner in given partial areas and the work piece is axially extended by the radial and axial advancement of the at least one flow turning roller, whereby areas (16, 17, 19) having different wall thickness are produced. The profile of the rim is then formed.

Description

Pressure rolling method and apparatus

The invention relates to a method for producing vehicle wheels with a rim made of a steel material, in which a tubular element with a uniform wall thickness is clamped as a workpiece in a press-rolling machine and at least one profile roller is fed radially, through which the workpiece is drawn in radially and a rim profile is formed.

Furthermore, the invention relates to a device for pressure rolling, in particular tube elements for the production of rims, with a pressure rolling unit.

In order to improve the driving properties, in particular the vibration and noise behavior, of vehicles in motor vehicle construction, the aim is to reduce the mass of unsprung vehicle parts. The reduction in mass, in particular of the vehicle wheels, plays an important role here.

Vehicle wheels are currently mainly made of steel or a light metal, in particular an aluminum alloy.

Compared to steel vehicle wheels, light metal vehicle wheels have the advantage that the lower specific weight of the light metal leads to vehicle wheels with a relatively low mass. For this reason, vehicle wheels made of light metal are increasingly used. However, steel has clear advantages over aluminum alloys in terms of the entire production process, from the production of the material to its recycling. The use of steel vehicle wheels is therefore desirable from a manufacturing, economic and ecological point of view.

It is therefore desirable to produce vehicle wheels made of steel which, like light alloy wheels, have a low mass.

The invention is based on the object of specifying a method and a device which allow the production of vehicle wheels from a steel material with a particularly low mass.

The solution of the task according to the invention is based on the gateways method and is characterized in that, before the rim profile is formed, the workpiece is clamped on a cylindrical rolling mandrel, the diameter of which corresponds to the inside diameter of the tubular element, that at least one is brought in by radial and axial infeed Spinning roller, the wall thickness of the workpiece is reduced in defined sub-areas and the workpiece is axially elongated, areas of different wall thicknesses being generated, and then the rim profile of the rim being molded.

A basic idea of the invention is that before the rim profile is formed, the material is reduced in those areas of the workpiece which are formed into rim areas in which, due to a slight gere mechanical load when using the rim a correspondingly lower wall or material thickness is sufficient.

In this way, an almost optimal, requirements-oriented material distribution can be set, which leads to the desired weight reduction of the vehicle wheels.

This is illustrated in the following example: A with the generic method, i.e. with uniform wall thickness, manufactured rim ring size 6.5 "x 15" has a mass of 4.2 kg. In contrast, a weight-optimized rim ring of the same size produced with the method according to the invention has a mass of 2.96 kg. The mass reduction is 1.24 kg per rim ring.

This high material saving goes hand in hand with a corresponding cost saving. With 900 rings to be produced per hour and the use of the production facility for over 5000 hours per year, the material saved is 5580 tons. At a current price of around DM 800 per ton, the material costs saved per year are DM 4,464,000.

In a preferred embodiment of the method according to the invention it is provided that the reduction in the wall thickness of the item of value is molded in by counter-rotating pressure rolls. With this special pressure rolling process, the material of the workpiece flows against the axial feed direction and is lengthened axially. Compared to other processes, in particular synchronous spinning, the opposing spinning rolling has the advantage that a particularly high strain hardening can be achieved, so that a very large one Strength of the material is achieved. This allows the setting of particularly thin wall thicknesses of the rim, which further reduces the mass of the vehicle wheel. It is also advantageous that the pipe section can be easily attached to the rolling mandrel. For example, in the case of synchronous spinning rolling, a cup formed on the tube piece is required, the bottom of which is pressed onto the free end of the rolling mandrel by means of tailstock force and pressure disk.

In addition, the counter-rotation pressure rolling has the advantage that the workpiece length is not limited by the longitudinal support stroke and the length of the mandrel. This allows a conversion of the spinning roll machine, e.g. There is no need to replace the mandrel to produce rims of different widths if the rim widths vary within certain limits.

A further preferred embodiment of the method according to the invention provides that a wall thickness that is greater than the adjacent areas is set at least in an axial central area of the workpiece. In this way, the wall thickness of the material in the areas adjacent to the central area is reduced to such an extent that the rim mass is as small as possible with a certain required load capacity of the rim. On the other hand, sufficient material is available in the central area so that a wheel bowl can be securely welded on.

It is particularly advantageous here if the axial central region is drawn in radially at the deepest when the rim profile is formed, and a rim bed with a large wall thickness is formed in the process. When moving in in the center area an increase in the wall thickness of the rim well, so that wheel disks or wheel disks can be welded to the rim well in a particularly reliable manner. Overheating and thus destruction of the material matrix during welding is counteracted particularly well.

In addition, the rim wall, which has a large wall thickness, is suitable for absorbing particularly high load forces which are transmitted at this point between the rim bed and the wheel disc.

Another preferred embodiment of the invention provides that a wall thickness is set in a region of the two free ends of the workpiece that is greater than the adjacent workpiece regions. It can be provided that the area of the two free ends is formed into a rim flange. In this way, rim flanges with the required high mechanical load-bearing capacity can be produced, with a smaller wall thickness being possible in the areas adjacent to the rim flanges.

A preferred embodiment of the method according to the invention provides that in the areas which are formed into the rim shoulders, the wall thickness of the workpiece is reduced in a defined manner and the strength of the steel material is increased in a targeted manner. In this way, the wall thickness is reduced in order to reduce the weight of the rim, the strength of the steel material being increased due to the cold work hardening which occurs as a result of the rim shoulders being formed. As a result, the mass of the rim can be significantly reduced with a high load capacity. A further embodiment of the method according to the invention provides that in at least one area which is formed into a rim shoulder, a partial area is formed into a rim hump. Depending on the requirements for the mechanical load-bearing capacity, the wall thickness of the workpiece in the partial area of the rim hump to be shaped can also be selected accordingly.

Furthermore, the solution to the object of the invention is based on the generic device for pressure rolling in that at least two pressure rolling units are provided, which are combined in one processing station, that a common feed device is provided, through which workpieces can be fed to the at least two pressure rolling units, and that a common discharge device is provided, through which workpieces can be removed from the at least two spinning roller units.

The device for pressure rolling according to the invention has the advantage that at least two workpieces can be machined side by side at the same time, which enables particularly effective and therefore inexpensive manufacture, in particular of rims, using the method according to the invention.

It is preferred here that the spinning roll units are arranged in the processing station with their main spindles parallel to one another. As a result, the workpieces can be supplied to and removed from the pressure-rolling units in a particularly simple manner.

It is particularly advantageous if the main spindles of the pressure roller units are arranged at a uniform distance from one another. The feeding and removal of the workpieces is made particularly simple in this way. In a further preferred embodiment of the device according to the invention, it is provided that the feed device and / or discharge device comprises a feed member or a discharge member for each pressure roller unit. In this way it can be achieved that the workpieces can be fed in parallel and picked up by the spinning roller units and / or can be delivered and discharged in parallel by the spinning roller units. This enables a particularly efficient production of rims.

In a further embodiment of the invention, it is advantageous that the feed and / or discharge members are movable and are arranged at a fixed distance from one another. It is particularly advantageous here if the uniform distance between the main spindles of the pressure-rolling units and the fixed distance between the feed and / or discharge members are the same. In this way, workpieces that are fed in at regular intervals can be picked up by the feed elements and fed directly to the main spindles of the spinning roller units. This advantage applies analogously to the corresponding laxative organs. All in all, this enables an even better increase in efficiency in the manufacture of the rims to be achieved.

A further preferred embodiment of the invention consists in that the feed device and / or discharge device has a transport channel for each spinning roller unit for feeding or discharging the workpieces. This makes it possible to implement a particularly cost-effective way of feeding or removing the workpieces.

It is further preferred that a central control unit is provided, through which the machining and / or feeding and / or removal of the workpieces can be controlled. On In this way, individual process steps of feeding or removing and processing the workpieces can be controlled independently of one another and can thus be controlled particularly reliably.

It is particularly advantageous here if the spinning roller units, the feed elements and the discharge elements can be individually controlled, in particular switched on and off, by the central control unit. This enables a particularly flexible control of the workpiece throughput and a capacity adjustment.

Finally, it is preferred that the spinning roller units, the feed elements and / or discharge elements are designed as uniform modules. On the one hand, this makes it easy to adapt a machine to customer requirements by assembling a corresponding number of modules. On the other hand, a module that has failed or is to be maintained can be replaced simply and quickly by a replacement module, so that a longer production downtime can be avoided. Finally, the modular design also brings cost advantages in the manufacture of the machine.

The invention is explained in more detail below with reference to drawings; it show in a highly schematic representation

1 shows a cross section through the wall of the tubular element.

FIG. 2 shows a cross section through the workpiece shown in FIG. 1 after the defined reduction in the wall thickness and axial lengths of the workpiece; FIG. 3 shows a cross section through the workpiece shown in FIG. 2 after the rim profile has been formed;

4 shows a view of the device according to the invention with a representation of the feed and discharge units;

Fig. 5 is a view of the device according to the invention with a representation of the pressure rolling elements.

FIGS. 1 to 3 show cross sections of the workpiece along cross sectional planes. The cross-sectional planes run parallel to the axis of rotation of the workpiece and include it. Due to the rotational symmetry of the workpiece shown in each case about its axis of rotation, only one side of the cross section through the workpiece along the cross-sectional plane is shown in the cross sections shown in FIGS. 1 to 3.

Figure 1 shows a cross section through the wall of the tubular element, which has a uniform wall thickness and forms the workpiece 10.

FIG. 2 shows a cross section through the workpiece 10 shown in FIG. 1 after the defined reduction in wall thickness and axial lengths. In the example shown, the initial wall thickness was left in an axial central area 11 of the workpiece 10, while the wall thicknesses of the adjacent areas, which are to form the rim shoulders, were reduced. In addition, in the area of the free ends 14 of the workpiece 10 for the rim flanges, the initial Leave wall thickness. In addition to the wall thickness, the strength and axial length of the intermediate mold were also set in a targeted manner in the pressure rolling carried out in some areas.

Figure 3 shows a cross section through the workpiece shown in Figure 2 after the molding of a rim profile.

In this example, the axial center region 11 was drawn in radially to the deepest by the molding in of the rim profile, a rim bed 16 having a large wall thickness being formed.

In addition, the example in FIG. 3 shows two rim flanges 17, each formed at the two free ends 14. The two rim shoulders 19 were each formed from the work-hardened areas with reduced wall thickness and additionally each have a molded hump 20.

FIG. 4 shows a partially sectioned view of a device according to the invention with three pressure roller units 25, a common feed device 30 and a common discharge device 31. In this example, the feed device 30 has a feed element 32 for each pressure roller unit 25, whereby the workpieces 10 separate the individual pressure roller units 25 can be supplied.

The feed members 32 each consist of a carriage 37 which is slidably mounted on a cross member 34 attached to support columns 33. A gripper arm 38 is attached to the carriage 37 in a vertically adjustable manner. A clamping gripping device 39 is attached to a free end of the gripping arms 38 for receiving workpieces 10. The carriages 37 are equally spaced from one another and are rigidly connected to one another. Furthermore, a feed station 36 is shown in FIG. 4, at which the workpieces 10 to be fed are made available for reception by the feed members. The feed station 36 can be designed, for example, as a conveyor belt with corresponding fastening elements 40 for receiving the workpieces 10 when they are made available. In principle, however, it is also possible to use a mobile pick-up and transport unit, such as a correspondingly designed pallet with fastening elements 40. The distance between the workpieces 10 brought up to the feed station 36 is preferably equal to the distance between the clamping gripping devices 39 from one another.

The discharge device 31 has a transport channel 35 for each press roll unit for removing machined workpieces 10 from the respective press roll unit 25. The transport channels 35 can have either a circular or rectangular cross section.

In the exemplary embodiment shown, both the pressure-rolling units 25 and the clamping gripping devices 39, the feed members 32 and the transport channels 35 are each at a uniform distance from one another.

FIG. 5 shows a sectional view of the device according to the invention with details of the structure of the pressure roller units 25, elements of the feed device 30 and discharge device 31 not being shown. In this exemplary embodiment, the individual workpieces 10 are machined by vertically feeding in each case two pressure-rolling rollers 26. Depending on the method step, the wall thickness of the workpiece 10 is reduced in certain partial areas and the workpiece 10 is axially elongated or the workpiece 10 is drawn in radially by delivering a corresponding profile roller and a rim profile is formed.

Claims

PATENT CLAIMS

1. A method for producing vehicle wheels with a rim made of a steel material, in which

- As a workpiece (10), a tubular element with a uniform wall thickness is clamped in a spinning roll machine and

- at least one profile roller is fed radially, through which the workpiece (10) is drawn in radially and a rim profile is formed, as a result of which,

- That the workpiece (10) is clamped on a cylindrical rolling mandrel, the diameter of which corresponds to the inside diameter of the tubular element, before the rim profile is formed,

- That by radial and axial infeed of at least one pressure roller (26), the wall thickness of the workpiece (10) is reduced in certain partial areas and the workpiece (10) is axially elongated, areas of different wall thicknesses being generated, and

- That the rim profile of the rim is then molded.

2. The method according to claim 1, characterized in that the reduction in the wall thickness of the workpiece

(10) is formed by counter-rotating pressure rollers.

3. The method according to claim 1 or 2, characterized in that at least in an axial central region (11) of the workpiece (10) a wall thickness is set which is greater than the adjacent regions.

4. The method according to claim 3, characterized in that the axial central region (10) is drawn in radially at the deepest during molding of the rim profile and thereby a rim well (16) with a large wall thickness is formed.

5. The method according to claim 4, characterized in that a wheel disk is welded onto the rim base (16) after the radial retraction.

6. The method according to any one of claims 1 to 5, characterized in that a wall thickness is set in a region of the two free ends (14) of the workpiece (10) which is greater than the adjacent workpiece areas.

7. The method according to claim 6, characterized in that the area of the two free ends is formed into a rim flange (17).

8. The method according to any one of claims 1 to 7, characterized in that defined in the areas which are formed to the rim shoulders (19), the wall thickness of the workpiece (10) and the strength of the steel material is increased.

9. The method according to claim 8, characterized in that in at least one area which is formed into a rim shoulder (19), a partial area is formed into a rim hump (20).

10. A device for pressure rolling, in particular of tubular elements for the production of rims according to one of the preceding claims, with a pressure rolling unit (25), thereby g e k e n n z e i c h n e t,

- That at least two spinning roller units (25) are provided, which are combined in a processing station (27),

- That a common feed device (30) is provided, through which workpieces (10) to the at least two spinning roller units (25) can be fed, and

- That a common discharge device (31) is provided, through which workpieces (10) from the at least two spinning roller units (25) can be removed.

11. The device according to claim 10, characterized in that the spinning roller units (25) in the processing station (27) are arranged parallel to one another with their main spindles.

12. Device according to one of claims 10 to 11, characterized in that the main spindles of the pressure-rolling units (25) are arranged at a uniform distance from one another.

13. The device according to one of claims 10 to 12, characterized in that the feed device (30) and / or discharge device (31) comprises a feed member or a discharge member for each pressure roller unit (25).

14. The apparatus according to claim 13, characterized in that the feed and / or discharge members are movable and are arranged at a fixed distance from one another.

15. The apparatus according to claim 12 and 14, characterized in that the uniform distance between the main spindles of the pressure roller units (25) and the fixed distance between the feed and / or discharge members are the same.

16. The device according to one of claims 10 to 15, characterized in that the feed device (30) and / or discharge device (31) has a transport channel (35) for feeding and discharging the workpieces for each pressure roller unit.

17. The device according to one of claims 10 to 16, characterized in that a central control unit is provided, through which the processing and / or feeding and / or removal of the workpieces (10) can be controlled.

18. The apparatus according to claim 17, characterized in that the spinning roller units (25), the feed elements and the discharge elements can be individually controlled, in particular switched on and off, by the central control unit.

19. Device according to one of claims 10 to 18, characterized in that the spinning roller units (25), the feed elements and / or discharge elements are each designed as uniform modules.