RU67487U1 - DEVICE FOR FORMING TEES - Google Patents

Abstract

The utility model relates to the field of metal forming, in particular, to devices for forming bends on the side surface of the pipe and can be used for the manufacture of thin-walled tees from a pipe billet.

The objective of the claimed utility model is to increase the durability of the working parts of the device, simplifying the design of the stamp and reducing its size.

The problem is solved due to the fact that in the device for forming tees, which consists of bases, two half-matrices with a plane of connector perpendicular to their longitudinal axis, two axial punches, a rigid mandrel and a forming element, according to the claimed utility model, the half-matrices are located horizontally on the lower base device, the forming element is made rigid and representing a hemisphere, the pole of which is cut off by a horizontal plane spaced from the center of the hemisphere at a distance H equal to:

H = (0.5-0.55) R _sf ;

where R _{sf is the} radius equal to the inner radius of the original tube billet;

on the sides of the forming element facing the axial punches, tides are made below its horizontal axis, having inclined planes at an angle of 45 ° to the vertical axis of the device and spaced from the center of the hemisphere at a distance h equal to:

h = (1.2-1.25) R _sf ;

the working ends of the axial punches facing the forming element have inclined planes parallel to the inclined planes of the tides, on opposite non-working ends of the axial

inclined bevels are made of the punches, the upper half of the device is equipped with two wedges having a working surface consisting of vertical and inclined planes, while the angle of inclination of the working plane of the wedges is equal to the angle of inclination of the bevels of the inoperative ends of the axial punches, and the angle of inclination of the inclined surface of the wedges is determined from the condition:

α = arctan (H _resp (0.8-0.9) D _tr );

where N _hole - the height of the formed branch on the tee

2 ill.

Description

The utility model relates to the field of metal forming, in particular, to devices for forming bends on the side surface of the pipe and can be used for the manufacture of thin-walled tees from a pipe billet.

A device is known for shaping tees using fluid pressure supplied to the inner cavity of a pipe billet (see Production of complex hollow parts. Edited by Prof. Bogoyavlensky KN - L.: Mechanical Engineering, Leningrad Branch, 1979, p. 55 , Fig. 20.).

The disadvantage of this device is that to implement the process of forming parts, you need expensive specialized equipment for hydraulic stamping, which also has limited use.

The closest in technical essence to the claimed device, which is taken as a prototype, is a device according to USSR author's certificate No. 1238824 "Device for shaping hollow products with processes." Published in Bul. No. 23, dated June 23, 86

The device consists of bases, two half-matrixes, a composite forming the inner punch, representing in cross-section complementary segments to the circumference of the segments, one of which is made of metal, the other of elastic material, as well as two axial punches. When the elastic element is compressed by axial punches, internal pressure is created, with the help of which the formation of the outlet on the side surface of the pipe billet is carried out.

For stable operation of the device, it is equipped with two buffers - upper and lower. The efforts of these buffers provide a dense docking along the plane of the half-matrix connector in the process of forming

the workpiece, and also provides the movement of the axial punches towards each other with the same speed relative to the matrix and the deformable workpiece.

The disadvantages of the device are as follows.

1. The forming element is made of an elastic medium, usually polyurethane SKU-7L. When forming tees from high-strength materials, high pressures arise in the elastic element, which lead to its quick failure. The elastic forming element is cut about the edge of the workpiece, as a result of which its volume is gradually reduced, the stable course of the process of deformation of the workpiece is disrupted. This leads to the fact that after the manufacture of 50-100 parts, it becomes necessary to replace it. Currently, the cost of polyurethane reaches 350 - 450 rubles / kg, which is an order of magnitude higher than the cost of high-quality tool steels.

2. Another disadvantage of the device is its complexity and bulkiness. The presence of buffers increases the height of the device and requires the use of more powerful presses with a large closed press height.

The objective of the claimed utility model is to increase the durability of the working parts of the device, simplifying the design of the stamp and reducing its size.

The problem is solved due to the fact that in the device for forming tees, which consists of bases, two half-matrices with a plane of connector perpendicular to their longitudinal axis, two axial punches, a rigid mandrel and a forming element, according to the claimed utility model, the half-matrices are located horizontally on the lower base device, the forming element is made rigid and representing a hemisphere, the pole of which is cut off by a horizontal plane spaced from the center of the hemisphere at a distance H equal to:

H = (0.5-0.55) R _sf ;

where R _{sf is the} radius equal to the inner radius of the original tube billet.

On the sides of the forming element facing the axial punches, below its horizontal axis, tides are made having inclined planes at an angle of 45 ° to the vertical axis of the device and spaced from the center of the hemisphere at a distance h equal to:

h = (1.2-1.25) R _sf ;

the working ends of the axial punches facing the forming element have inclined planes parallel to the inclined planes of the tides. On opposite non-working ends of the axial punches, inclined bevels are made. The upper half of the device is equipped with two wedges having a working surface consisting of vertical and inclined planes, while the angle of inclination of the working plane of the wedges is equal to the angle of inclination of the bevels of the non-working ends of the axial punches. The angle of inclination of the inclined surface of the wedges is determined from the condition:

a = arctg (H _holes / (0,8-0,9) D _TP);

where N _hole - the height of the formed branch on the tee

D _Tr - the outer diameter of the original pipe billet.

The resistance and durability of the working parts of the device made of tool steel are several orders of magnitude higher than the resistance of elements made of polyurethane, which significantly increases the operability of the device before repair.

The presence on the wedges of a vertical working plane allows you to keep the half-matrix from opening during the formation of the tee. The presence of an inclined plane converts the vertical movement of the wedges into the horizontal movement of the axial punches, which move towards each other with the same speed relative to the half-matrixes, squeeze the forming element and with its help carry out the formation of an outlet on the side surface

pipe billet. There is no need for lower and upper buffers, simplified device design.

The device is illustrated in the drawing,

where: figure 1 shows the design of the device, to the right of the axis of symmetry - in the initial state, to the left - at the end of the process of forming the tee;

figure 2 - shows a side view of a rigid mandrel and forming element, placed in the initial position in the pipe billet.

The device consists of two half-matrices 1, which are located horizontally on the lower base of the device 2. In the working cavity of the half-matrices 1 there is a workpiece 3 in which the forming element 4 and the mandrel 5 are located. The forming element 4 is initially oriented in the groove of the mandrel 5 (see figure 2) . Two axial punches 6 are adjacent to the forming element 4, in such a way that the inclined planes of the tides on the rigid forming element 4 coincide with the inclined planes of the working inclined planes of the axial punches 6. Two wedges 8 are located on the upper base of the device 7, resting their support surface on the wall windows of the lower base 2. These windows act as counterclips for the wedges 8. The stops made on the lower base 2 prevent half-matrices 1 from opening in their lower part facing the lower base , in the process of deformation of the workpiece.

On the non-working ends of the axial punches 6, facing in the opposite direction from the forming element 4, bevels are made, the angle of inclination of which is equal to the angle of inclination of the inclined planes of the wedges 8.

The device operates as follows.

With the beginning of the working stroke, the wedges 8 enter the windows of the base 2, relying on their walls with their supporting surface. At this moment, the vertical working plane of the wedge fixes the end surface

half-matrix 1 in their upper part, which prevents them from opening during the deformation of the workpiece 3.

On the lower base 2 are also made ledges, which prevent the opening of the half matrix 1 in their lower part.

The vertical movement of the wedges 8, due to the presence of inclined planes on the wedges and bevels of the axial punches, during the working stroke of the device, causes the horizontal movement of the axial punches 6 in the direction of the forming element 4. Axial punches 6 with their working ends on which inclined planes are made at an angle of 45 °, they begin to displace the forming element 4 vertically upwards, which deforms the tube stock.

On the cylindrical surface of the axial punches made step ledges with a height equal to the thickness of the original tube billet. As the axial punches move in the direction of the forming element and the workpiece deforms, the end face of the workpiece abuts against these step ledges. After this, the axial compression of the workpiece begins, which ensures minimal thinning of the workpiece in the process of forming the outlet on the side surface of the pipe.

The process of deformation of the workpiece ends at the moment when the forming element under the influence of the inclined planes of the working ends of the axial punches 6 will completely form the tap on the side surface of the pipe billet and with its tides will abut against the inner surface of the upper part of the pipe billet 3.

That is, the process of shaping is conditionally divided into two stages: preliminary deformation of the workpiece by a forming element without axial compression of the workpiece and shaping of the outlet on the side surface of the pipe workpiece simultaneously with axial compression of the workpiece.

The most rational implementation of the deformation process is that the workpiece is thinned by a minimum during deformation. To a first approximation, this can be done in

under the assumption that the length of the longitudinal generatrix of the billet from the side of the moldable branch will not change during deformation. To achieve this condition, the inclined planes of the tides of the forming element 4 and the inclined planes of the working ends of the axial punches are made at an angle of 45 ° to the vertical axis of the device. At the second, final stage of the tee forming process, when the workpiece is most deformed, an inclination angle of 45 ° ensures the equality of horizontal movement of the workpiece end face during axial compression of the pipe workpiece to the vertical movement of the forming element with the formation of a branch on the side surface, and ensures that the length of the forming workpiece remains unchanged.

Horizontal movement of axial punches is possible if the angle of inclination of the working surface of the wedge "α" and the inclined planes of the working ends of the punches adjoining it is connected with the friction coefficient "f" on the contacting surfaces by a known relation:

tgα≥f

where: f is the coefficient of friction on the contact surface between the inclined surfaces of the wedges and axial punches.

The most rational value of the angle of inclination of the working surface of the wedges is in the range from 15 to 25 degrees (see Romanovsky V.P. Handbook of cold stamping - L .: Engineering, 1971, p. 562, Fig. 503).

When the angle of inclination is less than 15 °, the stroke of the device increases excessively. When the angle is more than 25 °, the magnitude of the force that must be applied to implement the process of deforming the workpiece increases.

The rigid mandrel 5, which is included in the composite punch, plays a dual role. Firstly, it preserves the shape of the workpiece during the formation of the branch, prevents distortion of the shape of the workpiece and its loss of stability on the opposite side of the formed branch.

Secondly, using the rectangular groove of the mandrel 5 (see figure 2), the forming element 4 is initially oriented relative to the axial punches 6.

From the triangle ABC (see figure 1), you can approximately determine the minimum value of the angle of inclination of the inclined working plane of the wedge a. The minimum value of the BC leg is equal to the working stroke of the axial punch H _holes . A leg from geometric constructions is equal to (0.8-0.9) D _tr. Then the minimum value of the angle α is determined:

The geometry of the forming element 4 is determined from the following conditions.

The working surface of the forming element 4 is performed in the form of a sphere with a cut off pole. This form provides the manufacture of a flat platform at the end of the formed branch, which simplifies the manufacture of holes for subsequent flanging.

The horizontal plane with which the hemisphere pole was cut off is separated from the hemisphere center at a distance H equal to:

H = (0.5-0.55) R _sf , where R _sf is the radius equal to the inner radius of the original pipe billet.

If this distance is performed less than 0.5 R _sf , there is an irrational decrease in the height of the formed branch. If this distance is increased more than 0.55 R _sf , the diameter of the flat platform at the end of the moldable branch decreases, its shape more and more differs from the cylindrical one, and for the manufacture of the side of the required shape, the degree of deformation must be increased during subsequent flanging.

The tides on the forming element 4 are necessary so that the inclined ends of the axial punches in their closest position when approaching each other do not abut against each other. For this, the inclined planes of the tides are removed from the center of the hemisphere at a distance h = (1.2-1.25) R _sf .

The tides of the forming element (see figure 2) are located below the center of the hemisphere from which the forming element is formed, at a distance of (1.5-2) S _o , where: S _o is the thickness of the initial tube billet. The cross section of the tides is a rectangular quadrangle, the upper side of which is described by a curve with a radius equal to the inner radius of the billet. At the end of the deformation process, when the forming element rests with its tides on the inner surface of the pipe billet, this shape of the tides leaves no residue on it.

The transverse geometry of the inner forming element 4 (see figure 2) is determined by the fact that it together in the mandrel 5 should be able to accommodate in the cavity of the tube stock in the initial state.

Claims (1)

A device for forming hollow tees by forming an outlet on the side surface of a pipe billet, consisting of bases, two half-matrixes, the plane of the connector between which is perpendicular to their longitudinal axis, two axial punches, a rigid mandrel and an internal forming element, characterized in that the half-matrixes are located horizontally on the bottom the basis of the device, the forming element is made rigid and representing a hemisphere, the pole of which is cut off by a horizontal plane spaced from the center of the hemisphere n and a distance H equal to: N = (0.5-0.55) R _sf , where R _sf is the radius equal to the inner radius of the original pipe billet, on the sides of the forming element facing the axial punches, below its horizontal axis, tides are made having inclined planes at an angle of 45 ° to the vertical axis of the device and spaced from the center of the hemisphere at a distance h equal to: h- (1.2-1.25) R _sf ; the working ends of the axial punches facing the forming element have inclined planes parallel to the inclined planes of the tides, inclined bevels are made on the non-working ends of the axial punches, the upper half of the device is equipped with two wedges having a working surface consisting of vertical and inclined planes, and the angle of inclination of the working the plane of the wedges is equal to the angle of inclination of the bevels of the inoperative ends of the axial punches, and the value of the angle of inclination of the inclined plane of the wedges is determined from the condition: α = arctan (N _resp / (0.8-0.9) D _tr ), where N _hole - the height of the formed branch on the tee; D _Tr - the outer diameter of the original pipe billet.