A constant pressure variable motor hydraulic source pressure stabilizing circuit

Abstract

The application relates to the technical field of hydraulic system pressure regulating, and particularly provides a constant-pressure variable motor hydraulic source pressure stabilizing loop which comprises an oil feeding structure, a variable motor mechanism, a control slide valve structure, a throttle valve, a cooler and an oil tank. The pressure comparison between the two ends of the control slide valve enables the control slide valve to relatively slide with respect to the control slide valve shell, the flow of the variable motor is changed through a differential variable piston, pressure regulating is completed, the pressure regulating efficiency is improved, and efficient and stable pressure is finally realized. In addition, the input shaft of the quantitative plunger pump and the input shaft of the variable motor are coaxially arranged, the pressure oil energy flowing through the variable motor can be directly transmitted to the rotating shaft of the quantitative plunger pump, and is directly used for doing work to the oil outlet end of the quantitative plunger pump, so that the output power of the double-output-shaft motor is reduced, and the overflow loss of the quantitative plunger pump is greatly reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydraulic system pressure regulating, and particularly relates to a constant-pressure variable motor hydraulic source stabilizing circuit. BACKGROUND

[0002] The constant-pressure variable motor hydraulic source stabilizing circuit has the advantages of simple structure, fast response time and the like, and has become a widely used pressure regulating circuit in the hydraulic system.

[0003] The constant-pressure variable motor hydraulic source stabilizing circuit supplies oil through a hydraulic pump, a part of the oil is supplied to the hydraulic system, and the remaining part is returned to the oil tank through an overflow valve, and the system working pressure is regulated through the overflow valve. However, the output power of the hydraulic pump in the existing constant-pressure variable motor hydraulic source stabilizing circuit is not adjustable, the overflow loss is large, the pressure regulating efficiency is low, and the like, so that the existing constant-pressure variable motor hydraulic source stabilizing circuit is not suitable for being applied to a high-pressure large-flow hydraulic system, and the application of the hydraulic source circuit is limited.

[0004] When the pressure of the hydraulic system is regulated by using the existing constant-pressure variable motor hydraulic source stabilizing circuit, there is usually a large overflow loss, especially under the working condition of high pressure and small flow, the overflow loss is larger, and thus the energy utilization rate of the hydraulic system is low. Therefore, how to reduce the overflow loss of the constant-pressure variable motor hydraulic source stabilizing circuit, improve the energy utilization rate of the hydraulic system, and save energy cost is a problem to be solved by the person skilled in the art. SUMMARY

[0005] In view of the fact that the output power of the hydraulic pump in the existing constant-pressure variable motor hydraulic source stabilizing circuit is not adjustable, the pressure regulating efficiency of the hydraulic system is low, the application provides a constant-pressure variable motor hydraulic source stabilizing circuit to solve the above technical problems.

[0006] The application provides a constant-pressure variable motor hydraulic source stabilizing circuit, which comprises an oiling structure, a variable motor mechanism, a control spool structure, a throttle valve, a cooler and an oil tank; the variable motor mechanism comprises a constant-displacement plunger pump, a double-output-shaft motor, a variable motor, a motor variable unit and a fixed throttle; the oil inlet end of the oiling structure is connected to the oil tank, the oil outlet end of the oiling structure is connected to the oil inlet end of the constant-displacement plunger pump,

[0007] The first oil outlet end of the quantitative piston pump is connected to the oil inlet end of the variable motor, the oil outlet end of the variable motor is connected to the oil tank, the second oil outlet end of the quantitative piston pump is connected to the oil tank through the throttle valve and the cooler in sequence, the third oil outlet end of the quantitative piston pump is connected to the first oil inlet end of the motor variable unit and the oil inlet end of the control spool structure, the second oil inlet end of the motor variable unit is connected to the first oil outlet end of the control spool structure, and the oil outlet end of the motor variable unit is connected to the oil tank through the fixed throttle.

[0008] The second oil outlet end of the control spool structure is connected to the oil tank.

[0009] The motor variable unit comprises a motor variable upper shell, a motor variable lower shell, a differential variable piston and an auxiliary spring, the upper part of the differential variable piston forms a first sliding pair with the motor variable upper shell, the lower part of the differential variable piston forms a second sliding pair with the motor variable lower shell, and the sliding of the differential variable piston can form a first oil cavity between the top end of the differential variable piston and the motor variable upper shell and / or form a second oil cavity between the bottom end of the differential variable piston and the motor variable lower shell.

[0010] The motor variable lower shell is connected to the third oil outlet end of the quantitative piston pump through the oil conveying pipeline installed at the first oil passing hole.

[0011] The motor variable upper shell is provided with a second oil passing hole and a third oil passing hole, one end of the first oil cavity is connected to the first oil outlet end of the control spool structure through the oil conveying pipeline installed at the second oil passing hole, the other end of the first oil cavity is connected to the oil tank through the oil conveying pipeline installed at the third oil passing hole, and the oil conveying pipeline installed at the third oil passing hole is provided with a fixed throttle valve.

[0012] The control spool structure comprises a control spool shell, a control spool, a pressure control spring and a pressure regulating screw, the control spool is installed inside the control spool shell and forms a sliding pair with the control spool shell, the pressure regulating screw is threadedly connected with the control spool shell, the pressure control spring is arranged between the control spool and the pressure regulating screw, and the sliding of the control spool can form a third oil cavity between the control spool and the control spool shell and / or form a fourth oil cavity between the control spool and the pressure regulating screw.

[0013] The control slide valve is also capable of forming a fifth oil cavity between the control slide valve and the control slide valve housing, the third oil cavity is connected to the third oil outlet of the quantitative plunger pump, the fourth oil cavity is connected to the oil tank, the first end of the fifth oil cavity is connected to the first oil cavity, and the second end of the fifth oil cavity is connected to the third oil outlet of the quantitative plunger pump.

[0014] Further improvements of the technical solution are that a first pressure gauge, a first pressure gauge switch and a pressure sensor are arranged on the oil conveying pipeline between the quantitative plunger pump and the variable motor, the first pressure gauge switch is arranged directly on the oil conveying pipeline of the first pressure gauge, and the pressure sensor is connected to an external host computer.

[0015] Further improvements of the technical solution are that the oil feeding structure comprises an oil suction filter, a motor, a lifting vane pump and a direct-acting overflow valve, the oil inlet end of the oil suction filter is connected to the oil tank, the oil outlet end of the oil suction filter is connected to the oil inlet end of the lifting vane pump, the oil outlet end of the lifting vane pump is connected to the oil inlet end of the quantitative plunger pump, the oil outlet end of the lifting vane pump is also connected to the oil tank through the direct-acting overflow valve, and the output end of the motor is connected to the driving end of the lifting vane pump.

[0016] Further improvements of the technical solution are that the oil feeding structure further comprises a second pressure gauge and a second pressure gauge switch, one end of the second pressure gauge switch is connected to the oil conveying pipeline between the lifting vane pump and the quantitative plunger pump, and the second end of the second pressure gauge switch is connected to the second pressure gauge.

[0017] Further improvements of the technical solution are that an air filter is further arranged on the oil tank.

[0018] Further improvements of the technical solution are that a liquid level meter is further arranged in the oil tank.

[0019] The beneficial effects of the present application are that, by controlling the pressure difference between the two ends of the control slide valve, the control slide valve is relatively slid relative to the control slide valve housing, the flow of the variable motor is changed through the differential variable piston, the pressure regulation is completed, the pressure regulation efficiency is improved, and finally the efficient and stable pressure regulation is realized; in addition, the input shaft of the quantitative plunger pump and the input shaft of the variable motor are coaxially arranged, the pressure oil energy flowing through the variable motor can be directly transmitted to the rotating shaft of the quantitative plunger pump, and is directly used to do work on the oil outlet end of the quantitative plunger pump, so that the output power of the double-output shaft motor is reduced, and the overflow loss of the quantitative plunger pump is greatly reduced.

[0020] In addition, the present application has reliable design principle, simple structure and very wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to make the technical solution in the present application or the prior art clearer, the accompanying drawings needed in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0022] Figure 1 is a structural schematic diagram of the constant-pressure circuit.

[0023] 111 is an oil filter, 112 is an electric motor, 113 is a lifting vane pump, 114 is a direct-acting overflow valve, 115 is a second pressure gauge, 116 is a second pressure gauge switch, 121 is a constant-displacement plunger pump, 122 is a double-output shaft electric motor, 123 is a variable motor, 1231 is a swash plate push rod, 124 is a motor variable upper shell, 125 is a motor variable lower shell, 126 is a differential variable piston, 127 is an auxiliary spring, 128 is a fixed restrictor, 131 is a control slide valve shell, 132 is a control slide valve, 133 is a pressure control spring, 134 is a pressure regulating screw, 141 is a first pressure gauge, 142 is a first pressure gauge switch, 143 is a pressure sensor, 150 is a throttle valve, 160 is a cooler, 170 is an oil tank, 180 is an air filter, and 190 is a liquid level gauge. DETAILED DESCRIPTION

[0024] In order to make the technical solution in the present application or the prior art clearer, the accompanying drawings needed in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0026] As Figure 1 shown, the present application provides a constant-pressure variable motor hydraulic source constant-pressure circuit, comprising: an oil supply structure, a variable motor mechanism, a control slide valve structure, a throttle valve, a cooler and an oil tank.

[0027] In order to filter dust and moisture contained in the air entering the oil tank, the present application further provides an air filter, which is installed on the oil tank.

[0028] In order to better understand the oil level in the oil tank, the oil level gauge is arranged in the oil tank.

[0029] Specifically, the oil feeding structure comprises an oil suction filter, a motor, a lifting vane pump and a direct-acting overflow valve, the oil suction filter is connected to the oil tank at an oil inlet end, the oil suction filter is connected to the lifting vane pump at an oil outlet end, the lifting vane pump is connected to the fixed displacement piston pump at an oil inlet end, the lifting vane pump is further connected to the oil tank through the direct-acting overflow valve at an oil outlet end, and the motor is connected to the driving end of the lifting vane pump at an output end.

[0030] In order to measure the inlet pressure of the fixed displacement piston pump, the oil feeding structure is further provided with a second pressure gauge and a second pressure gauge switch, one end of the second pressure gauge switch is connected to the oil pipeline between the lifting vane pump and the fixed displacement piston pump, and the second end of the second pressure gauge switch is connected to the second pressure gauge.

[0031] In addition, the variable displacement motor mechanism comprises a fixed displacement piston pump, a double-output shaft motor, a variable displacement motor, a motor variable unit and a fixed restrictor, the oil inlet end of the fixed displacement piston pump is connected to the oil feeding structure, the first oil outlet end of the fixed displacement piston pump is connected to the oil inlet end of the variable displacement motor, the oil outlet end of the variable displacement motor is connected to the oil tank, the second oil outlet end of the fixed displacement piston pump is connected to the oil tank through the restrictor and the cooler in sequence, the third oil outlet end of the fixed displacement piston pump is connected to the first oil inlet end of the motor variable unit and the oil inlet end of the control spool valve structure, the second oil inlet end of the motor variable unit is connected to the first oil outlet end of the control spool valve structure, and the oil outlet end of the motor variable unit is connected to the oil tank through the fixed restrictor; the swash plate push rod arranged on the variable displacement motor is hinged to the differential variable piston in the motor variable unit; the first output end of the double-output shaft motor is connected to the driving end of the fixed displacement piston pump, and the second output end of the double-output shaft motor is connected to the driving end of the variable displacement motor; the second oil outlet end of the control spool valve structure is connected to the oil tank; the flow of the variable displacement motor is changed by adjusting the swash plate push rod on the variable displacement motor, the pressure regulation is completed, the pressure regulation efficiency is improved, and finally the high-efficiency pressure stabilization is realized.

[0032] In order to realize automatic adjustment of the variable motor, a motor variable unit is arranged, wherein the motor variable unit comprises a motor variable upper shell, a motor variable lower shell, a differential variable piston and an auxiliary spring, the upper part of the differential variable piston forms a first sliding pair with the motor variable upper shell, the lower part of the differential variable piston forms a second sliding pair with the motor variable lower shell, the sliding of the differential variable piston can form a first oil cavity between the top end of the differential variable piston and the motor variable upper shell and / or form a second oil cavity between the bottom end of the differential variable piston and the motor variable lower shell; the first end of the auxiliary spring is installed at the bottom end of the differential variable piston, and the second end of the auxiliary spring abuts against the top end of the motor variable lower shell; the motor variable lower shell is provided with a first oil passing hole, and the motor variable lower shell is connected to the third oil outlet end of the quantitative piston pump through an oil conveying pipeline installed at the first oil passing hole; the motor variable upper shell is provided with a second oil passing hole and a third oil passing hole, one end of the first oil cavity is connected to the first oil outlet end of the control slide valve structure through an oil conveying pipeline installed at the second oil passing hole, and the other end of the first oil cavity is connected to an oil tank through an oil conveying pipeline installed at the third oil passing hole, and a fixed throttle valve is arranged on the oil conveying pipeline installed at the third oil passing hole; the oil pressure of the first oil cavity and the oil pressure in the second oil cavity are changed to drive the differential variable piston to slide up and down, and then the swash plate push rod hinged on the differential variable piston is moved, the flow of the variable motor is adjusted, the pressure regulation is completed, the pressure regulation efficiency is improved, and finally the efficient and stable pressure is realized.

[0033] In order to realize automatic pressure regulation, a control slide valve structure is arranged for the circuit, the control slide valve structure comprises a control slide valve shell, a control slide valve, a pressure control spring and a pressure regulating screw, the control slide valve is installed inside the control slide valve shell and forms a sliding pair with the control slide valve shell, the pressure regulating screw is threadedly connected with the control slide valve shell, the pressure control spring is arranged between the control slide valve and the pressure regulating screw, the sliding of the control slide valve can form a third oil cavity between the control slide valve and the control slide valve shell and / or form a fourth oil cavity between the control slide valve and the pressure regulating screw; the sliding of the control slide valve can also form a fifth oil cavity between the control slide valve and the middle part of the control slide valve shell, the third oil cavity is connected to the third oil outlet end of the quantitative piston pump, the fourth oil cavity is connected to an oil tank, the first end of the fifth oil cavity is connected to the first oil cavity, and the second end of the fifth oil cavity is connected to the third oil outlet end of the quantitative piston pump; by comparing the given pressure applied to the control slide valve by the pressure spring and the oil pressure in the third oil cavity, the position of the control slide valve in the control slide valve shell is changed, then the size of the fifth oil cavity is changed, then the size of the first oil cavity is changed, then the differential variable piston slides relative to the motor variable upper shell and the motor variable lower shell, then the swash plate push rod hinged on the differential variable piston is moved, the flow of the variable motor is adjusted, the pressure regulation is completed, the pressure regulation efficiency is improved, and finally the efficient and stable pressure is realized.

[0034] In order to measure the pressure of the oil inlet end of the motor variable unit, the first pressure gauge, the first pressure gauge switch and the pressure sensor are arranged on the oil pipeline between the quantitative plunger pump and the variable motor, the first pressure gauge switch is arranged on the oil pipeline of the first pressure gauge, and the pressure sensor is connected to an external host computer.

[0035] The end area A0 of the control slide valve, the spring force F of the pressure spring and the given pressure P0 are stored in the host computer. s The oil pressure P in the third oil cavity is received by the host computer. d The host computer compares the sizes of P0 and P. d If P d <P0, the opening degree x of the control slide valve is 0, the pressure P of the upper end of the differential variable piston is 0, and the differential variable piston pushes the swash plate push rod of the variable motor to the position of γ=0 under the pushing of the oil pressure P d of the lower end of the differential variable piston, γ represents the included angle between the swash plate push rod and the driving shaft of the variable motor, and the input flow q of the variable motor is 0. In addition, the spring force F of the pressure spring and the given pressure P0 can be changed by adjusting the pressure adjusting screw. s

[0036] When the inlet pressure of the variable motor increases to the given pressure, that is, P d =P0, the hydraulic pushing force P d A0 of the left end of the control slide valve will overcome the spring force F s of the right end, the valve port in the fifth oil cavity is opened, a variable throttle port with an opening degree x is formed, a series resistance circuit is formed by the variable throttle port and the fixed throttle, and the pressure P of the upper end of the differential variable piston can be controlled by using the series resistance circuit. When the opening degree x increases, the pressure P rises, and when the opening degree x increases to a certain degree, the pressure P can push the variable piston to move downward, drive the swash plate push rod, increase the γ angle, and increase the flow of the variable motor.

[0037] The pressure spring is a force comparison element, and it is required to have a stable spring force F s to ensure a stable given pressure P0, so the stiffness of the pressure spring is required to be small, and the spring pre-compression is mainly used to obtain F s . Because the control slide valve does not directly push the swash plate, but pushes the differential variable piston and then pushes the swash plate push rod, the size of the control slide valve can be very small, and therefore the stiffness of the pressure spring is required to be small.

[0038] ​​Although the present application has been described in detail with reference to the preferred embodiments, it should be understood that the application is not limited to those preferred embodiments. Various equivalent modifications or changes in the application can be made all of which fall within the scope of the present application. Any modifications or changes in the application should be construed as falling within the scope of the present application. The scope of the application should be determined by the appended claims.

Claims

1. A pressure stabilizing circuit of a constant pressure variable displacement motor hydraulic source, characterized by, It comprises: an oiling structure, a variable motor mechanism, a control slide valve structure, a throttle valve, a cooler and an oil tank; the variable motor mechanism comprises a constant displacement piston pump, a double-output shaft motor, a variable motor, a motor variable unit and a fixed throttle; the oil inlet end of the oiling structure is connected to the oil tank, and the oil outlet end of the oiling structure is connected to the oil inlet end of the constant displacement piston pump, the first oil outlet end of the constant displacement piston pump is connected to the oil inlet end of the variable motor, the oil outlet end of the variable motor is connected to the oil tank, the second oil outlet end of the constant displacement piston pump is connected to the oil tank through the throttle valve and the cooler in sequence, the third oil outlet end of the constant displacement piston pump is connected to the first oil inlet end of the motor variable unit and the oil inlet end of the control slide valve structure, the second oil inlet end of the motor variable unit is connected to the first oil outlet end of the control slide valve structure, and the oil outlet end of the motor variable unit is connected to the oil tank through the fixed throttle; the swash plate push rod arranged on the variable motor is hinged to the differential variable piston in the motor variable unit; the first output end of the double-output shaft motor is connected to the driving end of the constant displacement piston pump, and the second output end of the double-output shaft motor is connected to the driving end of the variable motor; the second oil outlet end of the control slide valve structure is connected to the oil tank; the control slide valve structure comprises a control slide valve housing, a control slide valve, a pressure control spring and a pressure regulating screw, the control slide valve is installed inside the control slide valve housing and forms a sliding pair with the control slide valve housing, the pressure regulating screw is threadedly connected with the control slide valve housing, the pressure control spring is arranged between the control slide valve and the pressure regulating screw, and the sliding of the control slide valve can form a third oil chamber between the control slide valve and the control slide valve housing and a fourth oil chamber between the control slide valve and the pressure regulating screw; the sliding of the control slide valve can also form a fifth oil chamber between the control slide valve housing and the middle part of the control slide valve, the third oil chamber is connected to the third oil outlet end of the constant displacement piston pump, the fourth oil chamber is connected to the oil tank, the first end of the fifth oil chamber is connected to the first oil chamber, and the second end of the fifth oil chamber is connected to the third oil outlet end of the constant displacement piston pump; by comparing the given pressure applied to the control slide valve by the pressure spring and the oil pressure in the third oil chamber, the position of the control slide valve in the control slide valve housing is changed, the size of the fifth oil chamber is changed, the size of the first oil chamber is changed, the differential variable piston is caused to slide relative to the motor variable upper housing and the motor variable lower housing, the swash plate push rod hinged to the differential variable piston is moved, the flow of the variable motor is adjusted, and pressure regulation is completed.

2. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 1, characterized by The motor variable unit comprises a motor variable upper housing, a motor variable lower housing, a differential variable piston and an auxiliary spring, the upper part of the differential variable piston forms a first sliding pair with the motor variable upper housing, the lower part of the differential variable piston forms a second sliding pair with the motor variable lower housing, the sliding of the differential variable piston can form a first oil chamber between the top end of the differential variable piston and the motor variable upper housing and / or a second oil chamber between the bottom end of the differential variable piston and the motor variable lower housing; the first end of the auxiliary spring is installed at the bottom end of the differential variable piston, and the second end of the auxiliary spring abuts against the top end of the motor variable lower housing.

3. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 2, characterized by The first oil hole is arranged on the motor variable lower shell, and the motor variable lower shell is connected to the third oil outlet end of the quantitative plunger pump through the oil pipeline installed at the first oil hole.

4. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 2, characterized by The second oil hole and the third oil hole are arranged on the motor variable upper shell, one end of the first oil cavity is connected to the first oil outlet end of the control slide valve structure through the oil pipeline installed at the second oil hole, and the other end of the first oil cavity is connected to the oil tank through the oil pipeline installed at the third oil hole, and the oil pipeline installed at the third oil hole is provided with a fixed throttle valve.

5. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 1, wherein The first pressure gauge, the first pressure gauge switch and the pressure sensor are arranged on the oil pipeline between the quantitative plunger pump and the variable motor, the first pressure gauge switch is arranged directly on the oil pipeline of the first pressure gauge, and the pressure sensor is connected to an external host computer.

6. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 1, wherein The oil supply structure comprises an oil suction filter, a motor, a lifting vane pump and a direct-acting overflow valve, the oil suction filter is connected to the oil tank at an oil inlet end, the oil suction filter is connected to the lifting vane pump at an oil outlet end, the lifting vane pump is connected to the quantitative plunger pump at an oil outlet end, the oil outlet end of the lifting vane pump is also connected to the oil tank through the direct-acting overflow valve, and the output end of the motor is connected to the driving end of the lifting vane pump.

7. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 1, wherein The oil supply structure further comprises a second pressure gauge and a second pressure gauge switch, one end of the second pressure gauge switch is connected to the oil pipeline between the lifting vane pump and the quantitative plunger pump, and the second end of the second pressure gauge switch is connected to the second pressure gauge.

8. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 1, wherein An air filter is further arranged on the oil tank.

9. The constant-pressure variable-motor hydraulic source pressure-stabilizing circuit according to claim 1, wherein A liquid level meter is further arranged in the oil tank.

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