JPS6125445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to plastic metal forming operations using instantaneous high intensity magnetic fields and pulsed-pressure transfer fluids. In particular, the present invention relates to a hydraulic pulse forming apparatus for tubular workpieces of various diameters.

[Conventional technology]

A magnetic pulse forming device (IVBely
“Spravochnik po magnitoimpulsnoi” by et al.
obrabotke metallev” - Russian, Kharkov,
1977, p. 151) is known.

However, such devices are only used for deforming electrically conductive tubular members having a diameter within a certain range. Conversely, the use of said device for deforming tubular members of high-strength alloys, which do not conduct current well, presents many difficulties (the need to use highly conductive coupling devices, and the need to use a working coil This is particularly noticeable when deforming small-diameter pipes.

Similarly, a versatile electromagnetic forming device is known from US Pat. No. 3,618,350, which includes a working coil, a transmission member in the form of a wire mesh, a braided wire or a metal fabric, and a pressure transmission medium such as an elastic material. In this device, the electromagnetic field of the induction coil acts directly on the forming member which compresses the pressure transmission medium and deforms the tubular workpiece. The device can act on materials regardless of their electrical conductivity. However, when deforming a high-strength metal or alloy tubular member, the wear rate of the elastic material acting as a pressure transmission device is extremely high, leading to damage to the formed member and rendering the device unusable. Similarly, the wear resistance of the working coil for deforming tubes of small diameter (e.g. φ < 22 mm) made of high-strength materials is extremely low, so that the use of said device for deforming such tubes is quite problematic. .

Another drawback of the device, which limits its application, is its rather low efficiency during repetitive molding or correction operations. This is because, following the first pulse, repeated shaping or correction attempts are futile because a gap is formed between the surface of the already shaped workpiece and the shaping member.

Devices closest to those described herein are also known. This is a hydraulic pulse forming device for tubular parts (Soviet Union Inventor's Certificate No. 752900, Cl.
B21D26/28), a chamber with a device for generating pulse pressure in a liquid medium and converting it, a closing member with a high-pressure passage, and a die for giving the workpiece the required geometry. wherein the die is provided with an annular gap relative to the closure member to facilitate attachment of the tubular workpiece. The purpose of the high-pressure passage is to communicate the interior of the chamber with the working space defined by the side surface of the closure member and the wall of the tubular workpiece. The device is also provided with lines for supplying liquid to the working space.

In the case of devices of this type, pressure is concentrated by constriction of the passages and pulse pressures are created in the liquid by the shock wave of the explosion or by the energy due to the electro-hydraulic effect produced in the chamber.

The resulting pressure is transmitted via the liquid to the working chamber, and the tubular workpiece assumes the shape of a die.

However, said device has the disadvantage of poor stability of the power parameters, which is dependent on the properties of the working fluid, changes in the properties of the explosive and the wire used to detonate it, and corrosion of the electrodes. . Another disadvantage is the loss of energy of the shock wave which is diffused in all directions and absorbed by the members of the housing, thereby reducing the efficiency of the device. Moreover, since such a device must be equipped with a strong chamber with an intensifier tube and a shielding member, a large amount of metal is required for the manufacture of the device.

Since the provision of a constriction passageway in the center of the closure member laterally reduces the lateral metal compression capacity of the closure member, the closure member is particularly useful during the formation of tubular workpieces of small diameter (e.g. will separate, and the reliability of the device as a whole will be impaired.

[Problem that the invention seeks to solve]

The object of the invention is to provide a device for generating pulse pressures in a working liquid and converting them, ensuring directional propagation of shock waves in the working chamber when localized high-pressure pulses and extremely improving the power parameters. It is an object of the present invention to provide a hydraulic pulse type forming apparatus for tubular workpieces, which has a stabilizing closure member and which consumes less metal in the apparatus.

[Means for solving problems]

The present invention has the above object to provide a closing member having an annular groove provided in an outer wall forming a working chamber and to which a tubular workpiece can be attached, and a space surrounding the closing member and accommodating the tubular workpiece. a die having
A high-pressure passage provided in the closing member and opening into the working chamber, a supply pipe for supplying pressurized liquid to the working chamber via the high-pressure passage, and a device for generating and deforming pulse pressure transmitted to the pressurized liquid. The pulse pressure generating and deforming device is coaxially movable in a passage connected to the high pressure passage which is branched from the supply pipe and coaxially arranged in order from the working chamber. A plunger, an upper plate having mechanical strength that supports the lower end of the pressure booster plunger, a highly conductive lower plate that supports the upper plate, and a multi-turn induction coil for forming a pulsed electromagnetic field that supports the lower plate. The object of the present invention is to provide a hydraulic pulse forming apparatus for tubular workpieces, which is characterized by comprising:

Preferably, the base of the pressure intensifier plunger facing the upper plate contacts the upper plate at only one point and is pivotally interconnected.

It is also desirable that the base of the pressure booster plunger has a spherical cross section.

In order to increase the useful life of the device, the upper and lower plates are spaced apart from each other by a predetermined distance, the lower plate is formed as an annular disc member, and the walls of the chamber support the upper plate. It is desirable to have an annular collar of .

In order to improve the air-tightness effect, at least one annular groove with an elastic ring fixed therein is provided in the upper part of the closure member for placing the tubular workpiece to be deformed.
It is desirable to provide one.

It is advantageous if the elastic ring has a curved outer surface when viewed in cross section.

It is desirable to provide a check valve in the liquid supply pipe.

[Effect]

The hydraulic pulse forming device for tubular workpieces according to the invention reduces the energy loss when the shock wave dissipates into the housing of the chamber, stabilizes the power parameters of the localized pressure pulse and increases its value. and reduce the amount of metal needed to manufacture the device.

〔Example〕

Other features and advantages of the invention will be explained in more detail below with reference to the accompanying drawings, which illustrate embodiments of the invention.

FIG. 1 depicts a hydraulic pulse forming apparatus for tubular workpieces which includes a chamber 1 containing a plurality of turns of induction coil 2 for inducing an instantaneous magnetic field. Adjacent to the induction coil 2 is a lower plate 3 made of a highly conductive material and an upper plate 4 made of a mechanically strong material.

The pressure booster plunger 5 is mounted so as to be supported by the plate 4 via the base 5'. A spring-type device 6 for returning the pressure intensifier plunger 5 to its original position is fixed to the pressure intensifier plunger 5 . The cylindrical side surface of the pressure booster plunger 5 is firmly fitted into the bore of the power cylinder 7.

In the space located above the pressure booster plunger 5,
It is filled with a liquid indicated by number 8 supplied via a supply pipe 9 from a lift pump 10 which can be controlled by a level arm 11.

The device of the invention likewise includes a closure member 12 for preventing the leakage of liquid from the chamber 1, in which case the closure member 12 comprises a tubular workpiece 13 which can be attached to a shoulder 14 thereof. During installation, it also serves as a recoil and guide member.

The closing member 12 has a high-pressure passage 15 which is defined by the side wall of the closing member 12 and the tubular workpiece 13, which contains a tubular recess 17 which can be filled with a liquid 8, and a pressure intensifying plunger 5. communicate with the void located above.

The diameter of the shoulder 14 of the closure member 12 is
The diameter of the tubular workpiece 13 is smaller than that of the underlying portion, so that the tubular workpiece 13 is able to hold the shoulder 14 in the gap formed by the side wall of the shoulder 14 and the die 18 that tightly surrounds the tubular workpiece 13. It can be pressed upwards reliably. The side wall of the die 18 is formed with an annular forming groove 19 corresponding to the annular recess 17 of the closing member 12 and a groove for fixing the pressure sealing gasket.

A die 18 corresponding to the closure member 12 is secured to the upper part of the chamber 1 by means of a device such as a pressure cup 20. Further, a discharge passage 21 is provided in the upper part of the chamber 1, but in this case, the discharge passage 21 is connected to the lift pump 10.
It plays the role of communicating with the top of chamber 1.

The supply pipe 9 for supplying the liquid 8 has a check valve 22 whose purpose is to prevent leakage of the liquid 8 during the working cycle.

FIG. 2 now shows a sectional view of the chamber 1 of a hydraulic pulse forming device for a tubular workpiece, in which the lower plate 3 is of the disk type and is made of a highly conductive material. A collar 23 for supporting the upper plate 4 is provided on the inner wall of the chamber 1, and a gap 24 is provided between the upper plate 4 and the lower plate 3. The base 5' of the pressure booster plunger 5 is formed with a spherical cross section, and a recess 25 is formed in the upper plate 4 providing a projecting edge 26 for receiving the base of the pressure booster plunger 5. Pressure booster plunger 5
Due to the spherical shape of the base 5', the pressure intensifier plunger is supported only at a single point on the upper plate 4, and by the interaction of the base 5' with the protruding edge 26 of the recess 25, the pressure intensifier is Since the plunger 5 and the upper plate 4 are pivotally connected, engagement and disengagement during operation is prevented.

By providing the lower plate 3 in the form of a disc, the amount of metal consumed for the manufacture of the device can be reduced and the mechanical strength of the lower plate 3 can be increased.

By means of a gap 24 between the upper plate 4 and the lower plate 3, which is ensured by a collar 25 on the inner wall of the chamber 1,
The recoil impact of the upper plate 4 caused by the elastic deformation of the plate 4 can be prevented from being sent out against the lower plate 3 and the induction coil 2.

The pivotable connection between the upper plate 4 and the spherical surface of the base 5' of the pressure intensifier plunger makes it possible to compensate for any misalignment between the two parts and to maintain the pressure intensifier plunger 5 in its initial position. It can be returned to.

In FIG. 3, the closure member 12 is shown provided with a ring 27 of elastic material which is received by a groove 28. The outer side of the ring 27 is curved in cross-section, so that it ensures pressurized sealing of the working chamber (FIG. 1) if the diameter of the tubular workpiece 13 deviates from the rated diameter. Damage to the inner surface of the workpiece 13 is prevented.

The device of the invention operates as follows.

After the tubular workpiece 13 is mounted on the shoulder 14 of the closure member 12, the die 18 and pressure cup 20 tighten the tubular workpiece. For example, a liquid 8 such as water is supplied to the level arm 1 through a check valve 22.
1 from the lift pump 10 via the supply line 9 and further towards the cavity located above the plunger 5, the high-pressure channel 15 and the working chamber 16.

The electromagnetic pulse force is transmitted from the induction coil 2 by the lower and upper plates 3 and 4 to the plunger 5 which travels in the power cylinder 7 and produces a high pressure pulse in the passage 15 and the working chamber 16; The tubular workpiece 13 will be deformed within the die 18 and will assume the shape of an annular mold-forming groove 19 . If the tubular workpiece 13 is insufficiently formed, after supplying an additional amount of water to the working chamber 16, a shaping or correction operation is carried out and the tubular workpiece 13 is removed from the closure member 12. After the liquid 8 flows from the working chamber 16 into the space between the die 18 and the closure member 12, it reaches the upper part of the chamber 1 through the gap formed between the power cylinder 7 and the pressure cup 20. , is transferred from the chamber by the arm 11 and reaches the lift pump 10 along the discharge passage 21. A steel spring 6 returns the plunger 5 to its initial position. Since the plunger 5 and the power cylinder 7 have surfaces that fit tightly together, reliable airtight cooperation is possible. However, the tightness of the cooperating surfaces is limited to when the device is in a static state.
During activation of the high pressure pulse, liquid flow between the plunger 5 and the power cylinder 7 is prevented, so a high degree of tightness is not required. Therefore, it is not particularly necessary to seal the engagement surfaces of the tubular workpiece and the closing member.

According to the invention, it is possible to increase the efficiency of a hydraulic pulse forming device for tubular workpieces by reducing the energy consumption of the liquid 8 and by using mechanical pressure build-up. Additionally, the amount of metal required to manufacture the device is reduced since no special explosion chamber, pressure boost stage or protective shielding devices are used. Another advantage of the device according to the invention is that the power parameters are more stable, in particular because of the magnetic pulse generator and the precise electrical characteristics of the variable induction coil 2. Finally, the concentric arrangement of the high pressure passages 15 increases the reliability of the device and allows the deformation of tubes of fairly small diameter.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a hydraulic pulse type forming apparatus for tubular workpieces according to the present invention. FIG. 2 is an alternative cross-sectional view of the device according to the invention showing the chamber with the device for creating and transmitting liquid pressure. FIG. 3 is a drawing showing another type of closure member having an elastic ring on the upper part. 1... Chamber, 2... Multi-turn induction coil, 3... Lower plate, 4... Upper plate, 5... Pressure booster plunger,
5'... Base of the pressure booster plunger, 6... Pressure booster plunger return device, 7... Power cylinder, 8...
Liquid, 9...Liquid supply pipe, 10...Pushing pump, 11...Level arm, 12...Closing member,
13... Tubular workpiece, 14... Shoulder of closing member,
15... High pressure passage, 16... Work room, 17... Annular recess, 18... Die, 19... Annular forming groove,
20... Pressure cup, 21... Discharge passage, 22...
... Check valve, 23 ... Annular collar provided on the wall of chamber 1, 24 ... Gap between plates 3 and 4, 25 ...
A recess provided in the upper plate, 26...Protruding edge of the recess 25, 27...Elastic ring, 28...An annular groove.

Claims (1)

[Scope of Claims] 1. A closing member 12 having an annular groove provided in an outer wall forming a working chamber 16 and to which a tubular workpiece 13 can be attached; Dice 18 having a space for accommodating
a high pressure passage 15 provided in the closing member 12 and open to the working chamber 16; a supply pipe 9 for supplying the pressurized liquid 8 to the working chamber 16 via the high pressure passage 15;
The chamber 1 is provided with a device for generating and deforming pulse pressure to be transmitted to the pressure liquid, and the pulse pressure generation and deformation device is coaxially branched from the supply pipe 9 in sequence from the working chamber 16. a pressure intensifier plunger 5 that is movable in a passage communicating with the high pressure passage 15 coaxially arranged with the pressure intensifier plunger 5; an upper plate 4 having mechanical strength that supports the lower end of the pressure intensifier plunger 5; and an upper plate 4 that supports the upper plate 4. A hydraulic pulse forming apparatus for a tubular workpiece, comprising a highly conductive lower plate 3 and a multi-turn induction coil 2 for forming a pulsed electromagnetic field supporting the lower plate 3. 2. Device according to claim 1, characterized in that the base 5' of the pressure booster plunger 5 facing the upper plate 4 is in contact with the upper plate at one point and is pivotally interconnected. . 3. The device according to claim 2, characterized in that the base 5' of the pressure intensifying plunger 5 has a spherical cross section. 4. The lower plate 3 and the upper plate 4 are arranged with a gap 24 between them, the lower plate 3 being formed as an annular disk member, and the wall of the chamber 1 having a space for supporting the upper plate 4. Device according to claim 1, characterized in that it has an annular collar (23). 5. The upper part of the closing member 12 on which the tubular workpiece 13 is placed is provided with at least one annular groove 28 in which an elastic ring 27 is fixed. 4. The device according to any one of items 4 to 4. 6. Device according to claim 5, characterized in that the cross section of the elastic ring (27) has a curved outer surface. 7. The device according to any one of claims 1 to 6, characterized in that the liquid supply pipe 9 is provided with a check valve 22.