55results about How to "Improve fretting performance" patented technology

A hydraulic control system and a hydraulic control method are disclosed. The hydraulic control system comprises a first closed pump (P1) and a first engine (M1) connected with each other, a second closed pump (P2) and a second engine (M2) connected with each other, and a hydraulic motor (P3). The first closed pump (P1), the second closed pump (P2) and the hydraulic motor (P3) are connected in parallel. Compared with the prior art, the present hydraulic control system has advantages of wider engine model selection range, higher reliability and better micro-motion performance.

The invention discloses a hydraulic system and an engineering machine. The hydraulic system comprises a hydraulic pump, a main control valve, a pressure-difference adjusting valve and a controller. The pressure-difference adjusting valve is arranged between an oil discharging port of the hydraulic pump and a load feedback oil port of the main control valve and used for adjusting the differential pressure between the oil discharging port and the load feedback oil port; the input end of the controller is connected with an accelerator and used for receiving signals of the accelerator; the first output end is connected with the pressure-difference adjusting valve and used for controlling the pressure-difference adjusting amount of the pressure-difference adjusting valve according to the signals of the accelerator. According to the hydraulic system, the flow of a valve rod of the main control valve can be controlled according to the signals of the accelerator, so that an engine is either at an idle speed or at a high speed, and the adjustment on the flow within the whole stroke of the valve rod of the main control valve can be achieved, namely the flow adjusting gain of the main control valve is small at the idle speed, and the jogging performance is good; the flow adjusting gain of the main control valve is large at the high speed, and the requirements for large flow and high speed are met.

The invention discloses a rotary control valve unit, a rotary control hydraulic system and a crane. The rotary control valve unit comprises a proportional reversing valve, a shuttle valve and a fixed-difference overflow valve, wherein two oil inlets of the shuttle valve are respectively communicated with two working oil ports of the proportional reversing valve, oil outlets of the shuttle valve are communicated with a second pressure sensing port of the fixed-difference overflow valve, a first pressure sensing port of the fixed-difference overflow valve is communicated with oil inlets of the proportional reversing valve, and overflow oil ports are communicated with an oil return path. Under the loading state, the two pressure sensing ports of the fixed-difference overflow valve sense the pressure of the oil inlets and the high-pressure working oil ports of the proportional reversing valve, when the difference of the two pressures is larger than a preset value, the overflow pressure of the fixed-difference overflow valve is correspondingly adjusted, part hydraulic oil of a high-pressure oil source enters the oil return path for decompression through the overflow oil ports of the fixed-difference overflow valve so as to stabilize the difference of oil pressure of the oil inlets and load pressure of the proportional reversing valve, accordingly the influence on flow of the high-pressure working oil ports caused by load pressure changing is reduced, and load flow stability is improved.

The invention discloses a boom variable-amplitude hydraulic system. The system comprises a main pump, a main valve, a variable-amplitude oil cylinder, a first oil way and a second oil way. The first oil way is connected with a first cavity oil port of the variable-amplitude oil cylinder. The second oil way is connected with a second cavity oil port of the variable-amplitude oil cylinder. The first oil way is connected with a first work oil port of the main valve. The second oil way is connected with a second work oil port of the main valve. The main pump is connected with an oil inlet of the main valve, and a pressure control valve is arranged in the first oil way. The hydraulic system further comprises a servo pump and a servo oil way. The servo pump supplies oil to the servo oil way which is connected with a pilot oil port of the pressure control valve. A hydraulic valve is arranged in the servo oil way and controls the opening degree of the pressure control valve. The hydraulic system solves the problem that a balance valve in the prior art is frequently opened and closed and accordingly a beam waggles, and improves boom variable-amplitude operating stability and micro movement performance.

The invention discloses a method, device and system for processing handle signals. The method includes the steps of receiving the actual torque of an engine and a handle angle analog quantity input value of a control handle, determining a step size set value preset by a controller according to the received actual torque, detecting change values of the handle angle analog quantity input value in each control period, and determining a handle analog output quantity by comparing the change values of the handle angle analog quantity input value and the step size set value. By means of the technical scheme, the problems that after the controller is buffered and processed in correlative techniques, due to the fact that a buffer processing result is fixed, the requirement for more precise operation control can not be met, and the problem that system stability is poor can be solved.

The invention discloses a multi-way valve hydraulic system which comprises a multi-way valve set connected with a performing mechanism, first and second oil pumps connected with the oil supply line of the valve set, and a flow distributing and converging device, wherein the flow distributing and converging device is arranged between the second oil pump and the oil supply line; when the difference between the oil supply pressure of the oil supply line and the load pressure of the hydraulic system is greater than a preset value, the flow distributing and converging device is in a first state, so that hydraulic oil output by the second oil pump flows back to an oil tank through the flow distributing and converging device; when the difference between the oil supply pressure of the oil supply line and the load pressure of the hydraulic system is smaller than the preset value, the flow distributing and converging device is in a second state, so that the hydraulic oil output by the second oil pump enters the oil supply line to be converged with hydraulic oil in the first oil pump. The hydraulic system is capable of outputting the hydraulic oil with the corresponding flow quantity according to the flow quantity required by the performing mechanism, so that the energy waste is avoided and the smoothness and the micro-motion property of the system are improved. The invention further discloses a crane to which the multi-way valve hydraulic system is applied.

The invention discloses a rotary system and a crane, relates to the field of engineering machinery and is used for optimizing the performance of an existing crane rotary control system. The rotary system comprises a working oil pump, a micro oil pump, a rotary reversing valve and a changeover valve; the working oil pump is used for providing working pressure oil for the rotary reversing valve, and the working pressure oil flows to a rotary motor so as to realize the working steering of the rotary motor; the micro oil pump is used for providing micro pressure oil for the rotary reversing valve, the micro pressure oil flows to the rotary motor so as to realize the micromotion of the rotary motor; when the changeover valve is in an electric state, only the micro pressure oil provided by the micro oil pump can flow to the rotary motor; when the changeover valve is in a power-loss state, only the working pressure oil provided by the working oil pump can flow to the rotary motor through the rotary reversing valve. According to the technical scheme, the micro control of the rotary motor can be realized.

The invention discloses an electro-hydraulic compound control hydraulic system of a loader. The electro-hydraulic compound control hydraulic system comprises a hydraulic tank, an engine, a variable pump, an electric control reversing valve block, a first shuttle valve, a second shuttle valve, a third shuttle valve, a distribution valve, a pilot valve, a pilot oil source block, an electric control handle and a controller. The invention further provides a control method which uses the electro-hydraulic compound control hydraulic system of the loader. According to the electro-hydraulic compound control hydraulic system of the loader and the control method, staged compound control is performed according to actual working conditions of the loader, so as to guarantee good inching performance and manoeuverability when the loader slowly moves; when the loader quickly moves, energy losses can be further reduced, the loader can automatically adapt to actual load, and load impact on the pump is reduced; under high pressure and large load, the output of the hydraulic system is automatically adjusted, so as to reduce load impact on the engine and guarantee stable and reliable operation of the engine.

A valve element of a hydraulic multi-way valve comprises a valve element body, and the valve element body is provided with a first throttling groove set, a second throttling groove set, a third throttling groove set, a fourth throttling groove set and a fifth throttling groove set. The throttling groove sets of different shapes and different opening lengths are formed in the valve element body so that the flow of the valve element can be directly proportional to the whole process of valve element displacement; the impact phenomenon generated in the opening and closing process of the valve element can be effectively avoided, motion stationarity can be effectively achieved, and therefore microoperation performance and precise location of lifting or descending of a working device of a loader are improved.

The invention discloses a load sensitive hydraulic control system, comprising a multipath directional control valve and a load sensitive pump having a load sensitive valve, wherein, a liquid inlet and an oil drain port of the multipath directional control valve are respectively communicated with a liquid outlet and an oil tank of the load sensitive pump, a load feedback port of the multipath directional control valve is communicated with a sensitive cavity of the load sensitive valve, and each uniting valve oil port of the multipath directional control valve is respectively connected with the corresponding executive component; the passage between the load feedback port of the multipath directional control valve and the sensitive cavity of the load sensitive valve is provided with a damper valve; the oil duct between an oil inlet and an oil outlet of the damper valve is provided with at least two dampings, and the oil duct between the adjacent two dampings is provided with a chamber having an enlarged cross section; and the oil outlet is communicated with the load feedback port of the multipath directional control valve, and the oil inlet is communicated with the sensitive cavity of the load sensitive valve. In addition, the invention provides a crane having the load sensitive hydraulic control system.

The invention relates to a balance valve and an engineering machine. The balance valve comprises a loading cavity, an oil inlet cavity and a balance valve body core, wherein a first oil duct for communicating the loading cavity with the oil inlet cavity is arranged in the balance valve; the balance valve body core is provided with a second oil duct for communicating the loading cavity with the oil inlet cavity; when the balance valve is reversely opened, the initial section of the motion stroke of the balance valve body core is a cover stroke; and in the cover stroke, the first oil duct is closed, so that oil flows back through the second oil duct, wherein the through flow of the second oil duct is smaller than that of the first oil duct. In the cover stroke, the first oil duct is closed, the oil flows back through the second oil duct, and the through flow of the second oil duct is smaller than that of the first oil duct, thereby preventing instantaneous change of the pressure in the balance valve loading cavity and enhancing the jogging property of the system. The balance valve can avoid frequent opening and closing and prevent the hoisting system from being subjected to action impact, whipping or other phenomena, thereby enhancing the stability of the balance valve and system.

The invention relates to hydraulic oil cylinders, in particular to an ultra-high pressure sealed structure oil cylinder. The sealing problems of an ultra-high pressure oil cylinder or an oil cylinderwith large pressure fluctuations are solved. The ultra-high pressure sealed structure oil cylinder is composed of a cylinder body assembly and a piston rod assembly. The piston rod assembly is composed of a piston rod and a piston. The piston divides the internal space of the oil cylinder into a rod cavity and a rodless cavity. Valve core holes distributed symmetrically are formed in the outer round end surface of the rodless cavity side of the piston, wherein the valve core holes penetrates through the rod cavity. A left cone valve core and a right cone valve core are installed in the valve core holes, and the cone valve surfaces are compressed by springs. A through hole penetrating through the axis is formed in the bottom of a piston combined seal groove, the through hole is connected tothe two symmetrically distributed e valve core holes. A working principle is: when high pressure oil enters the rodless (rod) cavity of the oil cylinder, pressure oil opens the cone valve cores and acts on the bottom of the combined seal through the valve core holes and the through hole, the combined seal is compressed, and the compression amount of the combined seal is automatically adjusted according to the size of the oil pressure, so that the defects such as short life and large heat generation caused by high pre-compression of the high-pressure oil cylinder combined seal are overcome, and meanwhile, the fretting performance of the oil cylinder can be improved.

The invention relates to the technical field of hydraulic pressure, and discloses a pressure-difference valve unit, a hydraulic control system and engineering machinery. The hydraulic control system comprises a hydraulic pump, a main valve, a pressure-difference valve and a controller, wherein the hydraulic pump is used for providing hydraulic oil for an actuating element under the driving effectof an engine; the main valve is used for controlling the actual output flow of the hydraulic oil from the hydraulic pump to the actuating element; the pressure-difference valve comprises a variable-quantity valve and a variable-pressure valve; a constant-pressure element is arranged at a first end of the variable-quantity valve; the variable-pressure valve is arranged at a second end of the variable-quantity valve and is used for adjusting pressure difference between the two ends of the main valve under the different rotating speeds of the engine, so that the maximum output flow of the main valve adjusted by a handle in an output flow range is equal to the output flow of the hydraulic pump; and the controller is connected with the engine and the variable-pressure valve, is used for receiving the rotating speed of the engine, and controls the output pressure of the variable-pressure valve according to the rotating speed of the engine. The whole hydraulic control system runs at high speed and meanwhile has good micro-motion performance.