NL2003657C2

NL2003657C2 - Device for forming a flared hoop, mandrel, method for forming a flared hoop, flared hoop.

Info

Publication number: NL2003657C2
Application number: NL2003657A
Authority: NL
Inventors: Anton Podt
Original assignee: Fontijne Grotnes B V
Priority date: 2009-10-16
Filing date: 2009-10-16
Publication date: 2011-04-19

Description

P89013NL00

Title: Device for forming a flared hoop, mandrel, method for forming a flared hoop, flared hoop.

The invention relates to a device for forming a flared hoop.

Devices for forming a flared hoop are known. In particular, when manufacturing a rim, e.g. for tires of vehicles, one of the production steps is to provide flared ends on a hoop. The manufacturing process of a rim starts with 5 a steel plate that is formed into a hoop. The steel plate is coiled until a hoop is formed and the edges of the plate are abutting against each other. The abutting edges are welded together. However, before welding the edges together, the edge regions first need to be straightened to form a straight and flat welding surface. After welding the edges together, the hoop must be 10 rounded again. The straight and flat regions are re-rounded to form an approximately round hoop. Next, the hoop is provided with flared ends to prepare the hoop for flow forming by positioning a cone like mandrel in a side opening of the hoop for pressing the end flared outwards during which relatively large shear forces occur. During the flow forming step, as e.g.

15 described in International patent application WO 2006/014110 of the applicant, the hoop is axially stretched and radially thinned. A relatively round hoop with flared ends increases the efficiency and effectivity of the flow forming step. A drawback of re-rounding the hoop is that the hoop may not become really round, but a flattened region in the hoop remains. Also during 20 flaring, the flattened region remains. This decreases the efficiency and effectivity of the flow forming of the hoop.

An object of the invention is to provide a device that obviates at least one of the above mentioned draw backs.

Thereto, the invention provides a device for forming a flared hoop 25 comprising an expandable mandrel comprising a cylindrical body with at least one flared end, wherein the mandrel is adjustable between a first position in which the mandrel has a diameter and a second position in which the mandrel 2 has a larger diameter, wherein the device is arranged for positioning the mandrel in the first position in a hoop to be flared and for bringing the mandrel from the first position to the second position to provide the hoop with at least one flared end.

5 By providing an expandable mandrel that is adjustable between a first position with a certain diameter and a second position with a larger diameter, the hoop can be rounded and flared in one step. So, in the processing of a hoop until a rim one step can be omitted, thereby increasing the passage time of the hoop until a rim is formed.

10 By providing a mandrel comprising a cylindrical body and at least one flared end that is expandable between a first position having a certain diameter and a second position having a larger diameter, not only the flared ends but also the cylindrical body of the hoop is re-rounded by the mandrel.

In the first position of the mandrel, the mandrel can be positioned 15 approximately entirely in the hoop. The mandrel may be approximately entirely received in the hoop. Then the mandrel is expanded from the first position to the second position, this is a relatively large expansion step during which the diameter of the mandrel increases and the mandrel forms a flared end on the hoop and re-rounds the cylindrical body of the hoop.

20 The mandrel can be provided as a cylindrical body having one flared end, or as a cylindrical body having two flared ends. Preferably, the hoop is provided with two flared ends, so a mandrel having two flared ends can flare the hoop at once. Preferably, the mandrel with two flared ends is approximately as long as the hoop to be flared such that the mandrel can be 25 received approximately entirely in the hoop. If a mandrel is used with one flared end, two mandrels may be needed, one for each end. Also one mandrel can be provided that is first used to flare one end of the hoop and secondly is used for flaring the opposite end of the hoop.

3

By providing a mandrel with at least one flared end that can be approximately entirely received in the hoop to be flared, the device for flaring the hoop can become simpler.

By providing the mandrel with wedge like parts, a relatively easy 5 adjustment between the first position and the second position may be obtained. In the first position the wedge like parts may approximately abut against each other, the mandrel having a certain diameter. In the first position, the wedge like parts approximately abut each other, implying that a small gap may be present between the wedge like parts. In the second position a gap is provided 10 between adjacent wedge like parts, such that the mandrel has in the second position an outer diameter that is larger than the outer diameter in the first position. If a small gap is present in the first position, the gap between the wedge like parts in the second position is significantly larger. The mandrel has in fact widened.

15 By adjusting the mandrel with the wedge like parts from the first position to the second position by placing a pin approximately centrally in the mandrel for opening the gaps between the wedge like parts, the mandrel can be easily and reliably adjusted from the first position to the second position. The pin usually is tapered, beginning with a relatively small diameter 20 corresponding with the first position of the mandrel and ending with a relatively large diameter corresponding with the second position of the mandrel. By gradually entering the tapered pin in the mandrel, the mandrel is forced to open gradually until the second position is reached wherein a gap is provided between adjacent wedge like parts. By removing the pin from the 25 mandrel, the mandrel can be adjusted from the second position to the first position wherein the outer diameter of the mandrel is smaller than in the second position. When the mandrel is in the first position again, it can be removed from the flared hoop. The flared hoop can then be processed further e.g. in a rim manufacturing street.

4

The invention further relates to a method for forming a flared hoop comprising positioning the mandrel in the first position in a hoop to be flared; adjusting the mandrel from the first position to the second position to provide the hoop with at least one flared end and adjusting the mandrel from the 5 second position to the first position to remove the flared hoop from the mandrel. By applying the method, in one step the hoop can be approximately rounded by the mandrel in the second position and can be provided with a flared end. The flared hoop can thus be relatively simply and reliable be prepared for the next processing step in a rim manufacturing street, such as 10 flow forming.

The invention further relates to a hoop obtainable by the method.

The invention also relates to a mandrel for forming a hoop with a flared end.

Further advantageous embodiments are represented in the 15 subclaims.

The invention will further be elucidated on the basis of exemplary embodiments which are represented in a drawing. The exemplary embodiments are given by way of non-limitative illustration of the invention.

In the drawing: 20 Fig. 1 shows a schematic perspective view of a device according to the invention wherein the mandrel is in the first position; and

Fig. 2 shows a schematic perspective view of the device of Fig. 1 wherein the mandrel is in the second position.

It is noted that the figures are only schematic representations of 25 embodiments of the invention that are given by way of non-limiting example.

In the figures, the same or corresponding parts are designated with the same reference numerals.

Fig. 1 shows a device 1 for forming a flared hoop. The hoop is not shown. The device 1 comprises an expandable mandrel 2 having a cylindrical 30 body 3 and, in this embodiment, two flared ends 4. The mandrel 2 is adjustable 5 between a first position, shown in Fig. 1, and a second position, shown in Fig.

2. The outer diameter of the mandrel 2 in the second position is larger than the outer diameter of the mandrel 2 in the first position. The mandrel 2 comprises here wedge like parts 5 that approximately abut each other in the first 5 position. In the second position a relatively large gap 6 is provided between adjacent wedge like parts 5.

The mandrel 2 can be adjusted from the first to the second position by the pin 7. In this embodiment, the pin 7 is tapered, having a smaller diameter at the begin 7a than at the end 7b. The pin 7 is approximately 10 centrally gradually entered into the mandrel 2 thereby enlarging the outer diameter from the mandrel 2. The mandrel 2 can be provided approximately centrally with an opening 8. In the opening 8 of the mandrel 2, the pin 7 may be received and may be further protruded in the mandrel 2.

The device 1 is further provided with a stop means 9 against which 15 the hoop to be flared may abut. The stop means 9 are here provided as a flange at one end of the mandrel 2. The mandrel 2 can be approximately entirely received in the hoop to be flared until the hoop abuts against the flange 9. In the first position the outer diameter of the mandrel 2, inclusive of the flared ends 4, is smaller than the inner diameter of the hoop to be flared. Since the 20 hoop may only be accessed from one side by the mandrel 2, the device 1 for forming the flared ends on the hoop and for rerounding the hoop may be relatively simple.

The mandrel 2 can be expanded from the first position to the second position by protrusion of the pin 7 into the mandrel 2. The wedge like parts 5 25 of the mandrel 2 widen and gaps between the wedge like parts 5 become larger until the pin 7 approximately maximally protruded in the mandrel 2 and the mandrel 2 is in the second position. A relatively large stroke from the first position to the second position has been made. In the second position the cylindrical body 3, as well as the flared ends 4 of the mandrel 2 are in contact 30 with the hoop to be flared. In the second position of the mandrel 2, the hoop is 6 provided with flared ends corresponding with the flared ends 4 of the mandrel 2 and the hoop is approximately rounded again, corresponding with the outer diameter of the cylindrical body 3.

When the mandrel 2 is in the second position, the pin 7 may be 5 removed from the mandrel 2 and the mandrel 2 may close again, the gaps 6 between the adjacent wedge like parts 5 become smaller until the wedge like parts 5 approximately abut against each other or only a limited gap between the wedge like parts 5 is present and the mandrel 2 is in the first position again.

10 Many variants will be apparent to the person skilled in the art.

Additionally to or alternatively of a pin, a hydraulic cylinder may be used for expanding the mandrel from the first position to the second position. All variants are understood to be comprised within the scope of the invention as defined in the following claims.

15

Claims

A device for forming a flared ring comprising an expandable mandrel comprising a cylindrical body with at least one flared end, the mandrel being adjustable between a first position in which the mandrel has a diameter and a second position in which the mandrel 5 has a larger has a diameter, the device being arranged for placing the mandrel in the first position in the mandrel to be provided with a flared part and for bringing the mandrel from the first position to the second position to provide the ring with at least a flared end.

2. Device as claimed in claim 1, wherein the mandrel comprises wedge-shaped parts, wherein in the first position adjacent wedge-shaped parts lie substantially against each other and in the second position a gap is provided between adjacent wedge-shaped parts.

3. Device as claimed in claim 2, wherein the device is adapted for adjusting the mandrel between the first position and the second position by placing a pin substantially centrally in the mandrel for opening the gaps between the wedge-shaped parts.

Method for forming a flared ring using a device according to any of claims 1-3, comprising - placing the mandrel in the first position in a ring to be provided with a flared end; - adjusting the mandrel from the first position to the second position to provide a ring with at least one flared end; 25. adjusting the mandrel from the second position to the first position to remove the flared end ring from the mandrel.

A ring with at least one flared end obtainable with the method according to claim 4.

6. Mandrel for forming at least one flared end on a ring, the mandrel comprising a cylindrical body with at least one flared end and the mandrel being adjustable between a first position with a diameter and a second position with a larger diameter.

7. Mandrel as claimed in claim 6, wherein the mandrel comprises wedge-shaped parts, wherein in the first position adjacent wedge-shaped parts abut against each other and in the second position a gap is provided between adjacent wedge-shaped parts.