FORMING METHODS OF ONE-PIECE WHEELS WITHOUT WELDING SEAM MADE OF METAL SHEETS

Abstract

Forming methods of one-piece weldless wheels made of metal sheets including the steps of rolling, forming a primary wheel rim and a primary wheel disc, roll forming, compressing and shaping, in order to obtain one-piece weldless wheels. The methods can form weldless wheels by rolling, cold roll forming and cold extruding, which can reduce energy consumption by 45-55% and cut down material cost by 5-15% while improving strength of the wheel by 20-30%. A wheel with different thicknesses can be formed by the methods and can meet the requirements on mechanical strength. The methods can improve the precision of the wheel and minimize the swing value and jerk value. The wheel produced is safer, and the regular air tight test on the wheel is not necessary.

Claims

1. A forming method of a one-piece weldless wheel made of metal sheets, comprising the following steps: (1) rolling: placing a circular blank in a circular rolling mould, and rolling the circular blank into a wheel blank by performing planar synchronous rolling on the circular blank in the rolling mould using at least two rolling wheels symmetrically arranged along the circumferential direction of the rolling mould; (2) forming a primary wheel rim and a primary wheel disc: pressing the wheel blank to form the primary wheel rim and the primary wheel disc of the wheel made of metal sheets by applying pressure in the axial direction of the wheel blank using a concave pressing mould and a convex pressing mould; (3) roll forming: placing the wheel blank between a concave roll forming mould and a convex roll forming mould and clamping the wheel blank tightly with the concave roll forming mould and the convex roll forming mould; then rotating the concave roll forming mould and the convex roll forming mould synchronously around the axes thereof while pressing the primary wheel rim in the radial direction of the wheel blank by using one or more lateral pressing rollers, in order to extrude and further form the primary wheel rim precisely, wherein each lateral pressing roller is rotating around the axis thereof when pressing the primary wheel rim; (4) compressing and shaping: placing the wheel blank between a concave shaping mould and a convex shaping mould and pressing the wheel blank in the axial direction of the wheel blank with the concave shaping mould and the convex shaping mould while pressing the primary wheel rim of the entire circumference of the wheel blank in the radial direction of the wheel blank by using a lateral pressing shaping mould, in order that pressing, compressing and shaping can be performed simultaneously to form a one-piece weldless wheel made of metal sheets.

2. The forming method of a one-piece weldless wheel made of metal sheets according to claim 1, further comprising a step of forming the circular blank and punching a positioning hole before the step (1).

3. The forming method of a one-piece weldless wheel made of metal sheets according to claim 1, further comprising a step of extruding a center hole between the step (3) and the step (4).

4. The forming method of a one-piece weldless wheel made of metal sheets according to claim 1, further comprising a step of extruding screw holes between the step (3) and the step (4).

5. The forming method of a one-piece weldless wheel made of metal sheets according to claim 1, further comprising a step of extruding air holes between the step (3) and the step (4).

6. The forming method of a one-piece weldless wheel made of metal sheets according to claim 1, further comprising a step (5) of punching a valve hole on the one-piece weldless wheel made of metal sheets.

7. The forming method of a one-piece weldless wheel made of metal sheets according to claim 1, wherein rolling motions of the at least two rolling wheels in the step (1) comprise feed movements of the at least two rolling wheels in a horizontal direction and a rotation of each rolling wheel.

8. The forming method of a one-piece weldless wheel made of metal sheets according to claim 1, wherein, in the step (3), pressing the primary wheel rim in the radial direction of the wheel blank by using three lateral pressing rollers, in order to extrude and further form the primary wheel rim precisely, wherein the three lateral pressing rollers are arranged evenly along the circumferential direction of the wheel blank.

9. A one-piece weldless wheel made of metal sheets manufactured by the forming method of a one-piece weldless wheel made of metal sheets according to claim 1.

10. The one-piece weldless wheel made of metal sheets according to claim 9, wherein the one-piece wheel is made from carbon steel, aluminum, Mg—Al alloy or stainless steel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 shows a structure of a wheel made of metal sheets in the prior art.

[0036] FIG. 2 shows a schematic flow diagram of an embodiment of the forming method of the one-piece weldless wheel made of metal sheets according to the present invention.

[0037] FIGS. 3-14 show each step of the flow diagram represented in FIG. 2 respectively.

[0038] FIG. 15 shows a vertical cold rolling and roll forming machine used in the step of roll forming of an embodiment of the forming method of the one-piece weldless wheel made of metal sheets according to the present invention.

[0039] FIG. 16 shows a structure of a one-piece weldless wheel made of metal sheets according to the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0040] The forming method of the one-piece weldless wheel made of metal sheets according to the present invention will be further described by the following embodiments along with the drawings. However, it is known that the embodiments and related descriptions should not be the limitation of the present invention.

[0041] FIG. 2 shows a schematic flow diagram of an embodiment of the forming method of the one-piece weldless wheel made of metal sheets according to the present invention. And FIGS. 3-14 respectively show each step of the flow diagram represented in FIG. 2.

[0042] As shown in FIGS. 2-14, a one-piece weldless wheel made of metal sheets is manufactured by steps as follows:

[0043] B-1: Forming a circular blank 1 (as shown in FIG. 3).

[0044] B-2: Punching a center hole 2 on the circular blank 1 (as shown in FIG. 4).

[0045] B-3: Placing the circular blank in a rolling mould 3 with a circular outer profile. And then rolling the circular blank into a wheel blank 5 by performing planar synchronous staggered rolling on the circular blank in the rolling mould 3 using two rolling wheels 4 symmetrically arranged along the circumferential direction of the rolling mould 3. As shown in FIG. 5, in the embodiment, the rolling mould has two concave cavities which can correspondingly form two embossments on the lower surface of the rolled wheel blank. The rolling process can be performed by a rolling machine, such as the rolling machine disclosed in Chinese patent CN201744545U. However, it should be known that the devices which can perform the rolling process described in the present invention should not be limited to this rolling machine.

[0046] B-4: Press forming (i.e. forming a primary wheel rim and a primary wheel disc): Pressing the wheel blank to form the primary wheel rim and the primary wheel disc of the wheel made of metal sheets by applying pressure in the axial direction of the wheel blank using a concave pressing mould 7 and a convex pressing mould 6 (as shown in FIG. 6).

[0047] B-5, B-6, B-7: Three-station roll forming: Placing the wheel blank between a concave roll forming mould 9 and a convex roll forming mould 8 and then rotating the concave roll forming mould 9 and the convex roll forming mould 8 synchronously around the axes thereof while pressing the lateral wall portion of the wheel blank in the radial direction of the wheel blank in three times by using three lateral pressing rollers 10, 11 and 12 separately, in order to further form the primary wheel rim precisely. Each lateral pressing roller 10, 11 and 12 is rotating around the axis itself when pressing the primary wheel rim. In the present invention, the concave roll forming mould 9 and the convex roll forming mould 8 fully contact the wheel blank and clamp it tightly. The lateral pressing rollers 10, 11 and 12 press the wheel blank. In the embodiment, the wheel rim is further formed precisely by the lateral pressing rollers 10, 11 and 12 in three separate steps, wherein the lateral pressing roller 10 in step B-5 performs cold rolling and extruding of a deep groove R of the wheel rim by slowly pushing the material into the groove cavity and extruding (as shown in FIG. 7); the lateral pressing roller 11 in step B-6 performs cold rolling on the plane portion of the wheel rim in order to form a slope portion P to ensure that the shape of the wheel rim meets the shape requirement of the wheel rim preliminarily (as shown in FIG. 8); the lateral pressing roller 12 in step B-7 is used to complete the forming of the R side Q of the wheel rim (as shown in FIG. 9).

[0048] In this embodiment, the step of roll forming is performed by a vertical cold rolling and roll forming machine shown in FIG. 15. However, it should be known that this vertical cold rolling and roll forming machine shown in FIG. 15 is merely one kind of devices which can achieve the step of roll forming and cannot be deemed to be a limitation to the present invention.

[0049] As shown in FIG. 15, the vertical cold rolling and roll forming machine in the embodiment includes a frame including upper beam 51, base 52, base support bracket 53 and six upright posts 54 fixedly disposed between the upper beam 51 and the base 52. The six upright posts 54 are evenly disposed on a circumference centered on the axis of the vertical cold rolling and roll forming machine. Namely, the angle between two adjacent upright posts 54 is 60 degree. Lower transmission assembly 55 is disposed on the base 52. Three oil cylinder assemblies 56 are fixedly disposed on the upper beam 51. The rods of the oil cylinder assemblies 56 fixedly connect to sliding blocks 57 connecting to an upper press head assembly 58. Thus, the oil cylinder assemblies 56 can drive the upper press head assembly 58 to move along the axial direction (i.e. a vertical direction) of the vertical cold roll forming machine. Hydraulic motor(s) connect with the lower transmission assembly 55 and the upper press head assembly 58, in order to drive the lower transmission assembly 55 and the upper press head assembly 58 respectively rotate around the axial thereof in synchronization manner. Three lateral pressing roller assemblies 59 are evenly arranged on a circumference centered on the axis of the vertical cold roll forming machine. That is, the angle between two adjacent lateral pressing roller assemblies 54 is 120 degree. Each of three oil cylinders for the lateral pressing rollers connects to each lateral pressing roller assembly 59 respectively, in order to drive the lateral pressing roller assembly 59 to move in the radial direction of the circumference. These three lateral pressing roller assemblies can be moved synchronously or separately. Hydraulic motor(s) for the lateral pressing rollers connects with the lateral pressing roller assemblies 59 to drive each of the lateral pressing roller assemblies to rotate around the axis itself. The hydraulic motor(s) for the lateral pressing rollers can drive three lateral pressing roller assemblies to rotate synchronously or separately. A convex roll forming mould 510 fixedly connects to the upper press head assembly 58. A concave roll forming mould 511 fixedly connects to the lower transmission assembly 55. Furthermore, the vertical cold rolling and roll forming machine further includes a control system which is not illustrated in the figures. The control system may comprise displacement sensors respectively disposed on each feeding mechanism for the lateral pressing rollers, being used for detecting the feeding position of the lateral pressing roller assemblies; servo valves respectively connected to the hydraulic motor(s), the oil cylinders for the lateral pressing rollers and the hydraulic motor(s) for the lateral pressing rollers; PLC (programmable logic controller) connected to the displacement sensors, the servo valves and the oil cylinder assemblies, being used for controlling the rotating rates and feeding speeds of each element. For the convenience of roll forming process, the position of the lateral pressing roller assemblies in the axial direction (i.e. a vertical direction) of the vertical cold rolling and roll forming machine can be adjusted via an adjustment mechanism for the lateral pressing rollers which is connected to the lateral pressing roller assemblies.

[0050] The roll forming process using the above-mentioned vertical cold rolling and roll forming machine including the following steps:

[0051] (1) Placing the wheel blank into the concave roll forming mould 511.

[0052] (2) Controlling the oil cylinder assemblies 56 to drive the upper press head assembly 58 to move downward along the axial direction of the vertical cold rolling and roll forming machine until the wheel blank is pressed tightly by the convex roll forming mould 510.

[0053] (3) Controlling the hydraulic motor(s) to drive the lower transmission assembly 55 and the upper press head assembly 58 to rotate synchronously in order to rotate synchronously the convex roll forming mould 510, the concave roll forming mould 511 along with the wheel blank.

[0054] (4) Controlling the oil cylinders for the lateral pressing rollers to drive the lateral pressing roller assemblies to move in the radial direction (i.e. a horizontal direction) of the circumference in order to apply a deformation force onto the lateral wall portion of the wheel blank. Meanwhile, controlling the hydraulic motor(s) for the lateral pressing rollers to drive each lateral pressing roller assembly to rotate around the axis thereof until the roll forming process is completed.

[0055] B-8: Extruding a center hole 13 (as shown in FIG. 10).

[0056] B-9: Extruding screw holes 14 (as shown in FIG. 11).

[0057] B-10: Extruding air holes 15 (as shown in FIG. 12).

[0058] B-11: Compressing and shaping: Placing the wheel blank between a concave shaping mould 17 and a convex shaping mould 16 and pressing the wheel blank in the axial direction of the wheel blank with the concave shaping mould 17 and the convex shaping mould 16 while pressing the primary wheel rim of the wheel blank in the radial direction of the wheel blank by using a lateral pressing shaping mould 18, in order to form a one-piece weldless wheel made of metal sheets (as shown in FIG. 13).

[0059] B-12: Punching a valve hole (as shown in FIG. 14).

[0060] FIG. 16 shows a one-piece weldless wheel made of metal sheets, which is manufactured by above-mentioned steps. It can be seen from the figure that the shape of the one-piece weldless wheel made of metal sheets is the same as the shape of the wheel made of metal sheets in the prior art, while the one-piece weldless wheel made of metal sheets has no welding seam on the interim area between the wheel rim and wheel disc, which results in that the one-piece weldless wheel made of metal sheets has a much better performance on strength, rigidity and lifetime than the wheel made of metal sheets in the prior art.

[0061] The above description is merely embodiments in nature and is in no way intended to limit the invention, its application, or use.