CN114518285B - A fixture for expansion test of alloy sheathed pipe for railway through-ground wire - Google Patents

Abstract

The invention discloses a clamp for a railway through ground wire alloy sheath tube flaring test, which is characterized in that a fixing seat is provided with an inner hole, a clamp head is fixed in the inner hole of the fixing seat in a conical surface matching way, a press cap is connected and fastened with the fixing seat, the bottom wall of the inside of the press cap is tightly propped against the clamp head, the press cap is provided with a hole, an axial through hole is arranged in the clamp head, an alloy sheath penetrates through the press cap to enter the axial through hole in the clamp head, an inner center enters from the other end of the axial through hole, the inner center is sequentially provided with a taper surface section, a guide shaft section and a tail section, the taper surface section enters the alloy sheath, the taper surface is tightly propped against the inner wall of the alloy sheath, the guide shaft section is in sliding fit with the axial through hole of the clamp head, and the tail section is outside the axial through hole. The clamp has the beneficial effects that the alloy sheath pipe is clamped by the clamp, the sheath pipe cannot be clamped, deformed, bent and slid, the axis of the sheath pipe and the axis of the conical ejection core are always kept on the same straight line, the operation is simple and convenient, and the test is stable and good.

Description

Clamp for flaring test of alloy sheath tube of railway through ground wire

Technical Field

The invention relates to the field of wire and cable detection equipment, in particular to a clamp for a flaring test of an alloy sheath of a through ground wire product for a high-speed railway.

Background

The high-speed railway environment-friendly seamless metal through ground wire is mainly laid on two sides of a railway line, is a cable for uniformly grounding all railway signal systems, ensures reliable protection of personnel and equipment, and provides a discharge channel for overvoltage suffered by various equipment. The product works in severe conditions for a long period of time and can withstand severe vibrations. The flaring test of the outer sheath alloy pipe of the product must meet the requirements of the flaring test of the outer sheath of GB/T242-2007 standard and TB/T3479-2017 railway through ground wire 6.2.7, so that the quality and the service life of the product can be ensured. At present, a bench vice or other modes are adopted to clamp the sheath pipe, and then a cone with the angle of 60 degrees is adopted to extrude and expand the sheath pipe, so that the test requirement is met. The test method has the defects that in the test process, the sheath tube is clamped, extruded and flared, if the clamping force is too large, the sheath tube clamp is deformed and bent flatly, and if the clamping force is too small, the sheath tube slides in the extrusion and flaring process, the clamping force is not well held, the test requirement can not be met, and the quality requirement and the mechanical property of the sheath tube can not be ensured.

Disclosure of Invention

The invention provides a clamp for carrying out flaring test on a seamless environment-friendly railway through ground wire alloy sheath tube, which aims to solve the problem that the clamping force of the sheath tube is difficult to master.

The clamp for the railway through ground wire alloy sheath tube flaring test comprises a pressing cap, a fixing seat, a clamp head and an inner center, wherein the fixing seat is provided with an inner hole, the clamp head is fixed in the inner hole of the fixing seat in a conical surface matching way, the pressing cap is connected and fastened with the fixing seat, the bottom wall inside the pressing cap tightly clamps the clamp head, the pressing cap is provided with a hole for the alloy sheath to pass through, an axial through hole is arranged in the clamp head, the alloy sheath passes through the pressing cap and enters the axial through hole in the clamp head, the inner center enters the other end of the axial through hole, the inner center is sequentially provided with a conical surface section, a guide shaft section and a tail section, the conical surface section enters the alloy sheath, the conical surface tightly clamps the inner wall of the alloy sheath, the central shaft of the guide shaft section coincides with the central shaft of the axial through hole in the clamp head, the guide shaft section is in sliding fit with the axial through hole of the clamp head, and the tail section is outside the axial through hole.

Because chuck and interior top all take the tapering, dismantle difficult after pressing from both sides tight alloy sheath, for convenient dismantlement, still be equipped with further and dismantle cover, ejector pin, dismantle the cover setting and use threaded connection in the fixing base, dismantle the cover and be equipped with outer boss, the ladder hole, the terminal surface profile of outer boss place one end is less than fixing base axial through hole drill way girth (the terminal surface of outer boss place one end can get into the axial through hole and prop up the chuck terminal surface in, interior top's tapering face section, the guiding axle section can pass the ladder hole, interior top tail section is in dismantling the cover ladder hole, the ejector pin sets up in dismantling the cover with threaded connection mode top tight interior top tail section.

The tail section of the inner center is provided with a spherical surface, the inner center is pulled out, the inner center is convenient to grasp, and the force is increased.

The inner wall of the pressing cap is provided with threads, and the pressing cap is connected with the fixing seat in a threaded mode.

Preferably, the outer circle of the chuck is provided with taper, three uniformly distributed grooves are formed, the tail parts of the grooves are excessive through round holes, an annular groove is processed on the outer circumference where the round holes are located, and the annular groove is positioned in front of a contact area between the guide shaft section of the inner center and the axial through hole.

The clamp has the beneficial effects that the clamp is used for clamping the alloy sheath pipe, the sheath pipe cannot clamp, deform, bend and slide, the axis of a sample (sheath pipe) and the axis of the conical top core are always kept on the same straight line until the flaring test is finished, the operation is simple and convenient, and the test is stable and good.

Drawings

FIG. 1 is a block diagram of the present invention;

FIG. 2 is a block diagram of a chuck;

FIG. 3 is a block diagram of a collet in an axial view;

In the figure, 1 of an alloy sheath, 2 of a press cap, 3 of a fixing seat, 4 of a disassembly sleeve, 5 of a push rod, 6 of an inner center, and 7 of a chuck.

Detailed Description

The invention is further described with reference to the accompanying drawings, as shown in fig. 1, the outer surface of the chuck 7 is provided with a conical surface, the chuck 7 is fixed in the fixed seat 3 through conical surface matching, the press cap 2 is connected with the fixed seat 3 in a threaded connection mode, the bottom wall inside the press cap 2 presses the chuck 7, and the chuck 7 generates deformation to clamp the alloy sheath 1. The screwing length of the press cap 2 and the clamp head 7 can be controlled, so that the length of the clamp head 7 entering the fixed seat 3 is also controlled, the clamping force borne by the clamp head 7 can be adjusted, and meanwhile, the contact area between the alloy sheath and the inner hole wall of the clamp head is large, so that larger clamping force can be obtained, and the alloy sheath is not easy to deform. The inner center 6 is arranged in the chuck 7, the inner wall of the alloy sheath 1 is tightly propped by utilizing the small taper surface of the taper surface section of the inner center 6, the guide shaft section of the inner center 6 is in sliding fit with the inner hole of the chuck 7, the centering effect is good, and the central axis of the alloy sheath is coincident with the central axis of the inner hole of the chuck. The ejector rod 5 is arranged in the disassembly sleeve 4 and tightly pushes against the tail part of the inner center in a threaded connection mode. The ejector rod end face is a plane, the spherical surface at the tail part of the inner center 6 is in free contact with the ejector rod 5 and the plane of the disassembly sleeve 4 (in the state when the alloy sheath is clamped in fig. 1, when the alloy sheath is taken out and the inner center is disassembled, the end face of the inner hole of the disassembly sleeve 4 is in contact with the left side of the spherical surface under the action of threads), the guide shaft section of the inner center cannot generate radial resistance, and the small taper surface of the taper surface section of the inner center can uniformly tightly prop against the inner wall of the alloy sheath. The disassembly sleeve 4 is arranged in the fixed seat 3 and connected by screw threads. The outer circular boss and the inner hole end face of the disassembly sleeve 4 are respectively contacted with the tail plane of the chuck 7 and the left side of the tail sphere of the inner center 6 under the action of the screw thread, so that the chuck 7 can be conveniently ejected out, and the inner center 6 can be pulled out. As shown in FIG. 2 and FIG. 3, the outer circle of the chuck 7 is tapered, three grooves are uniformly distributed, the stress concentration at the tail of the groove is excessively reduced by a round hole, an annular groove is processed at the outer circumference of the round hole to reduce the wall thickness, and the thin wall is deformed by utilizing the taper. The annular groove is positioned in front of the contact area between the guide shaft section of the inner center 6 and the axial through hole, so that the deformation of the axial through hole caused by the taper action in front of the annular groove is avoided, and the guide shaft of the inner center 6 cannot slide.

The alloy sheath 1 firstly passes through the press cap 2 and then enters the chuck 7 in the use process. The press cap 2 is screwed into the fixed seat 3, the press cap 2 is propped against the clamp head 7, the clamp head 7 is forced to enter the inner hole of the fixed seat 3, the longer the press cap 2 is screwed in, the longer the clamp head 7 enters the inner hole of the fixed seat, and the larger the clamping force is applied to the alloy sheath 1 due to the existence of the conical surface of the clamp head 7. The inner center 6 enters the axial through hole of the chuck 7, the part of the taper surface section of the inner center 6 smaller than the inner diameter of the alloy sheath 1 stretches into the alloy sheath 1, the tail part of the inner center 6 is forced, the alloy sheath 1 is tightly extruded by the part of the taper surface section of the inner center 6 larger than or equal to the inner diameter of the alloy sheath 1, the inner center 6, the alloy sheath and the inner wall of the axial through hole of the chuck 7 are tightly contacted, and then the end head of the alloy sheath 1 is limited. The disassembling sleeve 4 is screwed into the fixing seat 3, the end face of the disassembling sleeve 4 is not contacted with the end face of the chuck 7, the ejector rod 5 is screwed into the disassembling sleeve 4, and the spherical surface of the tail part of the inner center 6 is propped. After the flaring of the alloy sheath is finished, the pressing cap 2 is unscrewed from the fixed seat 3, the disassembling sleeve 4 is screwed in further, the end face of the disassembling sleeve 4 is contacted with the end face of the clamping head 7, the clamping head 7 is partially ejected out, the contact between the clamping head 7 and the inner hole of the fixed seat 3 is loosened, and the clamping force of the clamping head 7 on the alloy sheath 1 is reduced. When the inner center 6 is separated, the disassembly sleeve 4 is continuously screwed in, the end face of the inner hole of the disassembly sleeve 4 contacts the left side of the spherical surface of the inner center 6, a backward pulling force is generated on the inner center 6, the taper surface section of the inner center 6 is released from being in close contact with the inner wall of the alloy sheath, and at the moment, the alloy sheath 1 is held, pulled out from the chuck 7 and separated from the press cap 2.

The conical core insert is pressed into the end of the sample for flaring by applying a force that is smooth in accordance with the flaring test procedure in the GB/T242-2007 standard until the desired outer diameter is reached. The axis of the conical shaped mandrel should be coincident with the axis of the sample during flaring. When the clamp is used for carrying out a flaring test of the alloy sheath pipe of the seamless environment-friendly railway through ground wire, the alloy sheath cannot slide under the fixation of the inner center, the operation is simple and convenient, the time and the labor are saved, the axis of a sample in the test process is always consistent with the axis of the 60-degree conical top core, the requirement of GB/T242-2007 standard is met, the flaring test of a product can be carried out, the sample is not damaged during the flaring test, the test process is convenient, stable and reliable, and the accuracy of the experimental result is ensured.

Claims (3)

1. A fixture for a railway ground-through alloy sheath pipe expansion test, characterized in that it comprises a pressure cap (2), a fixing seat (3), a chuck (7), and an inner center (6), wherein the fixing seat (3) is provided with an inner hole, the chuck (7) is fixed in the inner hole of the fixing seat (3) by means of a conical surface, the pressure cap (2) and the fixing seat (3) are connected and fastened together, the inner bottom wall of the pressure cap (2) presses against the chuck (7), the pressure cap (2) is provided with a hole for the alloy sheath (1) to pass through, an axial through hole is provided in the chuck (7), the alloy sheath (1) passes through the pressure cap (2) and enters the axial through hole in the chuck (7), the inner center (6) enters from the other end of the axial through hole, the inner center (6) is provided with a tapered surface section, a guide shaft section, and a tail section in sequence, the tapered surface section enters the alloy sheath (1), the tapered surface presses against the inner wall of the alloy sheath (1), the guide shaft section slides with the axial through hole in the chuck (7), and the tail section is outside the axial through hole; A disassembly sleeve (4) and a push rod (5) are also provided. The disassembly sleeve (4) is arranged in the fixed seat (3) and connected by threads. The disassembly sleeve (4) is provided with an outer cylindrical boss and a stepped inner hole. The end surface profile of one end where the outer cylindrical boss is located is smaller than the circumference of the axial through hole of the fixed seat (3). The tapered surface section and the guide shaft section of the inner center (6) can pass through the stepped inner hole. The tail section of the inner center (6) is in the stepped inner hole of the disassembly sleeve (4). The push rod (5) is arranged in the disassembly sleeve (4) and tightens the tail section of the inner center (6) in a threaded connection manner. The outer circle of the chuck (7) is tapered and has three evenly distributed grooves. The tail of the groove is transitioned to a circular hole. An annular groove is machined on the outer circumference where the circular hole is located. The annular groove is located before the contact area between the guide shaft section of the inner center (6) and the axial through hole. 2. A fixture for the expansion test of the alloy sheath pipe of the railway through-ground wire according to claim 1, characterized in that the tail section of the inner tip (6) has a spherical surface. 3. A fixture for the expansion test of the alloy sheath pipe of the railway through-ground wire according to claim 1, characterized in that: the inner wall of the pressure cap (2) is provided with a thread, and the connection method with the fixing seat (3) is a threaded connection.