JPH04322830A - Hydraulic pressure plastic tube expansion working device - Google Patents

Abstract

PURPOSE:To prevent the damage and the seizure of a seal bearing, when a columner rod is fitted into an annular die through the seal bearing. CONSTITUTION:An object to be worked 8, inserted and held by conical outside peripheral surfaces 1A, 2A of a pair of annular dies 1, 2 is subjected to tube expansion working by a hydraulic pressure medium led into a pressure chamber 9 and a wedge effect of the outside peripheral surfaces 1A, 2A. As the tube expansion advances, seal bearings 5, 6 to a rod 7 in the center are moved from the die small diameter side to the large diameter side.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic plastic tube expansion device, and is used, for example, to cold plastic tube expand a non-magnetic retaining ring for a generator using high hydraulic pressure.

0002

[Prior Art] Japanese Patent Application Laid-open No. 63-154231 states
A pair of annular dies having a conical outer circumferential surface are provided, with the small diameter ends of the conical outer circumferential surfaces facing each other, and a cylindrical rod is fitted into the center of the annular die via a sealed bearing, and the approaching direction A cylindrical workpiece is held between the conical outer circumferential surfaces of the annular die that is pressed, and hydraulic pressure is introduced into a pressurizing chamber that is an annular space between the cylindrical rod and the workpiece. Accordingly, an apparatus for performing hydroplastic pipe expansion of the workpiece through the conical outer circumferential surface of the annular die is disclosed, and the annular die A in this technology is formed of the inner part of the annular die A as shown in FIG. A seal groove A1 is formed on the circumference at a partial height h of the total height H from the small diameter portion, specifically at a position of 20 to 50% of the total height, and a seal for the cylindrical rod is provided in the seal groove A1.

0003

[Problems to be Solved by the Invention] Although the above-mentioned prior art is useful in its own way, since the mounting position of the seal (seal bearing) is fixed, it has the following problems. This hydraulic plastic tube expansion processing device holds a cylindrical workpiece from above and below between the conical outer circumferential surface A2 of an annular die A, and maintains the pressurized state while pressing the outer circumferential surface A2 of the annular die A.
2, high hydraulic pressure is introduced into the sealed internal space to expand the pipe, and as the workpiece expands, the internal pressure load range cannot be changed sequentially in accordance with external pressure load fluctuations. This may lead to excessive internal pressure, excessive external pressure, etc.

That is, the position of the seal groove A1 is determined by the distribution range of the external pressure applied to the outer circumferential surface A2 as the workpiece expands, and the corresponding distribution range of the internal pressure applied to the inner circumferential surface of the die A. Since the position of the seal groove A1, that is, the seal position, is fixed, it is not possible to respond to load fluctuations, resulting in damage to the seal material, seizing and sticking, and the resulting difficulty in disassembly. was there.

An object of the present invention is to make it possible to respond to load fluctuations by moving a sealed bearing as the workpiece expands.

[0006]

[Means for Solving the Problems] The present invention comprises a pair of annular dies 1 and 2 having conical outer circumferential surfaces 1A and 2A, with the small diameter ends of the conical outer circumferential surfaces 1A and 2A facing each other, Seal bearings 5, 6 are installed at the center of the annular dies 1, 2.
The conical outer circumferential surface 1 of the annular dies 1 and 2 is provided with a cylindrical rod 7 fitted thereinto and pressed in the approaching direction.
By sandwiching a cylindrical workpiece 8 between A and 2A and introducing hydraulic pressure into a pressurizing chamber 9, which is an annular space between the cylindrical rod 7 and the workpiece 8, the annular die is In order to achieve the above-mentioned object, the following technical measures are taken in an apparatus for performing hydroplastic tube expansion of the workpiece 8 through the conical outer circumferential surfaces 1A and 2A.

That is, the present invention provides the sealed bearing 5,
6 is the conical outer circumferential surface 1 as the workpiece 8 expands.
A, 2A is characterized in that it is disposed so as to be movable in the axial direction from the small diameter end side to the large diameter end side.

[0008]

[Operation] According to the present invention, as shown in FIG. 1, the cylindrical workpiece 8 is sandwiched between the conical outer peripheral surfaces 1A and 2A of the upper and lower pair of annular dies 1 and 2, and the pressurized state is maintained by the press. However, by introducing high-pressure liquid into the pressurizing chamber 9, which is an annular space sealed by the outer peripheral surfaces 1A and 2A, hydroplastic pipe expansion is performed.

At the start of machining, the seal bearings 5 and 6 are located at the small diameter end of the annular dies 1 and 2, and as the machining progresses and the workpiece 8 expands, the seal bearings 5 and 6 move from the small diameter end to the large diameter end. The workpiece 8 moves in the axial direction, thereby moving the workpiece 8
The internal pressure load range is sequentially changed according to the external pressure load range due to changes in the external diameter of the cylinder, thereby preventing excessive internal pressure, excessive external pressure, etc.

0010

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1 showing the overall configuration, a conical outer peripheral surface 1A
, 2A, a pair of annular dies 1 and 2 are mounted on a pressure plate 3.
and push-up cylinder 4, respectively, so that the small diameter ends of the conical outer circumferential surfaces 1A and 2A are placed one above the other with the small diameter ends facing each other.

[0011] Each center hole 1B, 2B of the annular die 1, 2
A cylindrical rod 7 is fitted into the annular dies 1, 2 through seal bearings 5, 6, and the upper and lower inner peripheries of the cylindrical workpiece 8 are pressed in the approaching direction.
It is held in place by contacting and sealing with A. The annular space between the cylindrical rod 7 and the workpiece 8 is a pressurized chamber 9, and in this illustrated example, high-pressure liquid can be introduced through a passage 1C formed in the lower annular die 1. At the same time, a passage 2C formed in the upper annular die 2
The pressure in the pressure chamber can be controlled and measured by the pressure gauge 10 via the pressure gauge 10.

In addition, in FIG. 1, the push-up cylinder 4
is fitted into the ram 11, and can be pressurized in the direction toward each other between it and the upper press plate 3 by the press pressure medium introduced through the path 12, and the press pressure is controlled by a pressure gauge 1.
It is measurable at 3. Referring to FIGS. 2-4, details of the sealed bearings 5, 6, etc. are illustrated. Although the following description will be made with reference to the lower annular die 1, the upper annular die 2 also has the same configuration.

In FIG. 2, the center hole 1 of the annular die 1
A seal groove 14 is formed in the axial direction through a stepped portion in B, and a seal bearing 5 is fitted into the seal groove 14 so as to be movable in the axial direction. The sealed bearing 5 (the same applies to the sealed bearing 6 as described above) includes a rubber O-ring 16, a resin packing 17, and pure copper on the top and bottom of a steel seal base 15, which is a split ring, as shown in FIG. A packing 18 is attached, and the seal base 15 is made into a split ring to facilitate assembly.

[0014] Separately from the seal bearing 5, a seal member 22 made of a rubber O-ring 19, a resin seal 20, a pure copper seal 21, etc. is installed, so that there is no space between the seal bearing 5 and the seal member 22. A first pressure chamber 23 for moving the seal bearing 5 in the axial direction is defined, and the opposite side to the first pressure chamber 23 is a second pressure chamber 24 communicating with the pressurizing chamber 9. A pressure medium from a pump 25 can be introduced into the first pressure chamber 23 via a passage 26 .

In the above embodiment, a pair of annular dies 1
, 2, and is sealed at the contact surface with the outer circumferential surfaces 1A, 2A. P1
By adjusting the press pressure P2, the annular die 1
, 2 are expanded due to the wedge effect of the conical outer circumferential surfaces 1A, 2A, and at the same time the annular dies 1, 2 are expanded.
2, the pressure of the pre-filled pressurized fluid increases and the parts other than the ends are machined.

By the way, in the present invention, before starting machining, the internal pressure (
That is, the same as the second pressure chamber 24) is predictable. Therefore, at the start of machining, by introducing a small volume of pressure medium from the pump 25 into the first pressure chamber 23, the sealed bearings 5, 6
are located on the small diameter end side of the annular dies 1 and 2, and the seal of this first pressure chamber 23 is formed by the O-ring 16 and the packing 17 facing the first pressure chamber 23 in the seal member 22 and the seal bearings 5 and 6. , 18.

The pressure at this time is set to the pipe expansion start pressure PA of the workpiece 8, but the pressure in the first and second pressure chambers 23, 2
4 is formed in the seal groove 14 of the same diameter, so
The seal bearings 5, 6 are held at the upper limit position until the pressure in the second pressure chamber 24 reaches PA. The workpiece 8 is work-hardened at the same time as it is expanded, and pressure P is applied to further expand the tube.
A higher pressure PN than A is required. This pressure PN is the second
When it acts on the pressure chamber 24, the sealed bearings 5 and 6 move by the increased pressure, and at the same time, the internal pressure is compressed because the volume is reduced and becomes PNA, and as the machining progresses, the sealed bearings 5 and 6 move toward the large diameter end side. The seal bearings 5 and 6 are moved in the axial direction to the workpiece 8, and the internal pressure load range of the seal bearings 5 and 6 is sequentially changed in response to the external pressure load range due to changes in the outer diameter of the workpiece 8, resulting in excessive internal pressure, excessive external pressure, etc. Never.

Incidentally, since the internal pressure caused by the first pressure chamber 23 is located on the larger diameter side of the annular dies 1 and 2, it can be almost ignored as the internal pressure applied to the dies.

[0019]

Effects of the Invention The present invention is as described above, and when a work piece is expanded by applying high hydraulic pressure using a pair of annular dies having a conical outer circumferential surface, the process of expanding the work piece is controlled. Since the seal bearing that moves in the axial direction performs sealing against the central cylindrical rod, damage to the seal material, seizure, sticking caused by these, and difficulty in disassembly can be eliminated.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a lower annular die according to an embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a sealed bearing according to an embodiment of the present invention.

FIG. 4 is a perspective view of a seal base that constitutes a sealed bearing according to an embodiment of the present invention.

FIG. 5 is a sectional view of a conventional annular die.

[Explanation of symbols]

1 Annular die 1A Conical outer circumferential surface 2　Annular die 2A　Conical outer peripheral surface 5 Seal bearing 6 Seal bearing 7 Cylindrical rod 8 Workpiece 9 Pressurized chamber

Claims (1)

[Claims] Claim 1: A pair of annular dies (1) and (2) each having a conical outer circumferential surface (1A) and (2A)
A) The small diameter ends of (2A) are arranged opposite to each other, and sealed bearings (5) and (6) are provided at the centers of the annular dies (1) and (2).
The cylindrical workpiece (8) is fitted between the conical outer peripheral surfaces (1A) and (2A) of the annular dies (1) and (2), which are pressed in the approaching direction. ) are held between the cylindrical rod (7) and the workpiece (8).
By introducing hydraulic pressure into the pressurizing chamber (9), which is an annular space between (8) In the apparatus for performing hydroplastic pipe expansion processing, the sealed bearing (
5) (6) is disposed so as to be movable in the axial direction from the small diameter end side to the large diameter end side of the conical outer peripheral surface (1A) (2A) as the workpiece (8) progresses. A hydraulic plastic tube expansion processing device characterized by: