Hydraulic hose crimping machine is the main equipment for manufacturing hydraulic hose joints. By crimping the joint jacket, the joint jacket, the hose and the joint inner core are integrated to form a hydraulic hose joint assembly. At present, the pressure withholding force of domestic design and manufacture or press modification is determined by experience, test, analogy and other methods. Therefore, the equipment capacity is too large, the volume and weight are too large and other defects and deficiencies. During the crimping process, there are disadvantages such as unstable crimping quality, low tube shrinking efficiency, and easy fatigue of operators. The improved crimping machine not only saves manpower, but also improves crimping quality and tube shrinking efficiency.

The hydraulic transmission and control system is the main power source of the hose compressor, and the compression process of the compressor is realized through the hydraulic transmission and control system. The improved design of the mechanical structure and control system of the existing hydraulic high-pressure hose compressor can greatly reduce the overall structure of the compressor, and strive to simplify the hydraulic transmission and control system as much as possible. The hydraulic high-pressure hose compressor designed in this paper is a kind of tube machinery that works on the principle of hydraulic transmission. By controlling the expansion of the piston rod of the thrust hydraulic cylinder to drive the contraction and release of the inner cone slider, the pressure of the high-pressure hose joint is realized.

1. The basic principle of hydraulic high pressure hose combination withholding.

(1) Simplified mechanical model of hydraulic high-pressure hose assembly The pressure structure of the hose assembly is generally composed of a shank, a hose and a core tube. The oil leakage of the hose joint refers to the oil leakage phenomenon of the connecting parts of the coating, the hose and the core tube. Therefore, this paper analyzes the connection part of the coating, the hose and the core tube, that is, the structure of the tail part of the tube. The basic principle of the high-pressure hose assembly is the plastic deformation of the outer casing under the action of external force, which causes the rubber layer of the hose to be tightly bonded to the outer wall of the core tube, thereby completing the sealing of the liquid medium in the hose.

(2) Design of hydraulic high pressure hose crimping machine.

The hydraulic high pressure rubber hose press consists of a pump station, a hydraulic cylinder, a pressure device, a guide mechanism, a control system and a support frame. The machine consists of an XRB2B emulsion pump matched with a 75kw motor, which converts electrical energy into hydraulic energy of the pump, and then delivers the pressure oil to the hydraulic cylinder, which expands the cylinder as the power for the pressure. The piston rod of the hydraulic cylinder is connected with the inner cone slider of the press through the guiding mechanism, and the double cone surface, the integral valve, and the elastic structure buckle die are fixed at the center position between the connecting rods. When the piston rod of the hydraulic cylinder is extended, the inner cone slider of the press is driven to move forward to clamp the pressure die, that is, the pressure hose; when the piston rod of the hydraulic cylinder is retracted, the inner cone slider of the press is driven to loosen the outer Cone slider, complete hose pressure. During the working process, the high-pressure liquid of the hydraulic system enters the piston cavity from the left inlet, pushes the piston rod 3 to extend outward, and compresses the outer cone slider 7 of the inner cone slider 6 through the push rod 5, so that the mold is elastically connected with the hydraulic hose . When the oil is supplied from the right side in reverse, the piston rod shrinks, the taper sleeve releases the compression of the mold, and the elasticity of the mold recovers, completing the compression cycle of the hose joint. In order to meet the pressure of all high-pressure hoses of different specifications and facilitate the replacement of pressure molds, the pressure molds are designed as a series of molds with the same structural form and related dimensions, but with different pressure diameters. In this way, the pressure of all high-pressure hoses of different specifications can be realized as long as different types of pressure molds are replaced. The pressure of the press directly affects the sealing performance, tensile strength and service life between the hose and the joint. According to the structural characteristics of the hose, the thickness of the pipe wall, the mechanical properties of the inner rubber and the structure type of the joint, the selection of pressure should be comprehensively considered.

2. Hydraulic high pressure hose withholding control.

In the actual production of rubber hose assemblies, there is a problem that the preparation process takes too long before the problem. In practical applications, during the first crimping process, it is necessary to carry out multiple pressure tests and adjust the position of the travel switch until the diameter of the outer jacket after crimping meets the requirements. There are also some compression quality that is difficult to guarantee. Due to the lack of theoretical research on the compression amount of the hose assembly, when the hose assembly is inconsistent with the standard assembly, no clear adjustment can be given.

The critical seal contact stress of each hose assembly is a certain value, and the critical relative compression is also a certain value. In the crimping process of the rubber hose assembly, as long as the relative compression amount reaches the critical relative compression amount, the crimping process can directly take the connection quality as the control target; there is no need to detect and fit the gap between the jacket and the steel wire/rubber composite layer. During the crimping process, four mechanical quantities can be detected online, namely the radial compression of the outer casing, the thrust F of the piston rod, the oil pressure P of the cylinder inlet and the radial compression S of the core. The thrust of the piston rod is consistent with the change law of the oil pressure, and the deformation of the inner hole of the inner sleeve is generally not more than 10 microns. During the crimping process, the assembly has an axial displacement compared to the measuring head, causing the measuring head to move in the less-smooth inner bore. Therefore, the inner hole cannot be measured to check the compression amount.

During the compression of the hydraulic high pressure rubber hose, the pressure values ​​show significantly different slope values. The contact stress between the inner rubber and the joint core begins to develop, which is called the location of the pressure characteristic area. Since the critical sealing contact stress of each hose assembly is a certain value, the corresponding relative displacement is also a certain value, and the critical sealing contact stress value can be determined by the pressure characteristic area.

The crimping principle of the hydraulic hose crimping machine is studied, the mechanical structure part of the crimping machine is designed, the various working conditions of the hose joint in the crimping process, the crimping required in the crimping process and the crimping of the hose joint are analyzed, so as to improve the efficiency of the crimping process. The connection quality of the high-pressure hose assembly is analyzed, and a new idea for formulating the crimping process is proposed according to the principle of plastic machinery. At the same time, on this basis, it provides a theoretical basis for the design of the computer control system of the crimping machine.