CN116576167A - Hydraulic system and hydraulic control method - Google Patents

Abstract

The present invention provides a hydraulic system and a hydraulic control method, comprising: a first variable displacement plunger pump and a second variable displacement plunger pump, the first variable displacement plunger pump is driven by a first driving part, and the second variable displacement plunger pump is driven by a The second drive part drives; the drive motor is used to drive the centrifugal pump, the first variable plunger pump and the second variable plunger pump are connected to the drive motor, the output oil of the first variable plunger pump and /or the output oil of the second variable displacement plunger pump is used to drive the drive motor to run; wherein, the hydraulic system has different displacement operating states, and the first variable displacement plunger pump is controlled according to the displacement operating state of the hydraulic system. The working condition and the working condition of the second variable plunger pump are controlled. The technical solution provided by the invention can solve the technical problem of high fuel consumption in the hydraulic system in the prior art when operating with a small displacement.

Description

Hydraulic system and hydraulic control method

technical field

The invention relates to the technical field of sand pump driving, in particular to a hydraulic system and a hydraulic control method.

Background technique

At present, the sand mixing vehicle automatically tracks the fracturing construction process through automatic control technology, and realizes automatic control of parameters such as liquid level, additive, density, and sand pump discharge pressure. Its function is to mix, stir, and transport fracturing media. The power unit of the sand mixing truck is the engine on the platform and the engine of the chassis vehicle under the platform. The engine on the platform and the engine of the chassis vehicle under the platform respectively control the clean water centrifugal pump, mixing tank, auger motor, various additive pumps, and hydraulic system heat dissipation. etc. and the operation of the sand pump, and adopt hydraulic drive. During on-site construction work, one sand mixing truck is matched with multiple fracturing trucks for operation, and the sand mixing truck plays a central role in the entire construction process. The fracturing fluid mixing vehicle is a vehicle-mounted continuous mixing of fracturing fluids on the job site, which meets the construction method of on-the-spot and on-site pressure. The power unit of the liquid mixing vehicle is the engine on the stage and the engine on the chassis below the stage. The operation of the fracturing fluid discharge pump is hydraulically driven. During on-site operation, the fracturing fluid mixing truck can be used to connect with the sand mixing truck to prepare and press on-the-spot. The matching of the existing two kinds of equipment is that the engine of the chassis vehicle drives the hydraulic single pump to drive the operation of the sand pump or adopts the confluence with the hydraulic pump driven by the engine on the platform to drive the operation of the sand pump.

However, when performing small-displacement operations on site, due to the need to cooperate with the operation of the fracturing vehicle, the rotational speed requirements of the sand pump or the fracturing fluid discharge pump are basically fixed. The engine and the under-stage engine also need to run simultaneously, resulting in high fuel consumption on site. At the same time, the load of the on-stage engine was too low, resulting in serious oil burning of the on-stage engine.

Contents of the invention

The main purpose of the present invention is to provide a hydraulic system and a hydraulic control method to solve the technical problem of high fuel consumption of the hydraulic system in the prior art when operating with a small displacement.

In order to achieve the above object, according to one aspect of the present invention, a hydraulic system is provided, including: a first variable displacement piston pump and a second variable displacement piston pump, the first variable displacement piston pump is driven by a first driving part, and the second variable displacement piston pump is driven by a first driving part. The two-variable plunger pump is driven by the second drive unit; the drive motor is used to drive the centrifugal pump, the first variable plunger pump and the second variable plunger pump are connected to the drive motor, the first variable plunger The output oil of the pump and/or the output oil of the second variable displacement plunger pump are used to drive the drive motor to run; wherein, the hydraulic system has different displacement operating states, and the hydraulic system has different displacement operating states according to the situation of the hydraulic system. The working condition of the first variable plunger pump and the working condition of the second variable plunger pump are controlled.

Further, the hydraulic system has a first displacement operation state and a second displacement operation state, the displacement of the first displacement operation state is greater than the displacement of the second displacement operation state; when the hydraulic system is in the first displacement operation state When the hydraulic system is in the working state of the second displacement, the first variable The plunger pump is in a non-working state, and the second-variable plunger pump is in a working state, and the working displacement of the driving motor is reduced to a preset displacement.

Further, the driving motor is a variable motor; when the hydraulic system is in the first displacement operating state, the swash plate inclination angle of the driving motor is kept at the maximum displacement; when the hydraulic system is in the second displacement operating state, the The inclination of the swash plate is adjusted to adjust the working displacement of the drive motor to a preset displacement.

Further, the drive motor is an electronically controlled motor; when the hydraulic system is in the first displacement operating state, the electronically controlled motor is in a power-off state; when the hydraulic system is in the second displacement operating state, the electronically controlled motor is in an electrified state, In order to make the electronic control motor adjust the inclination angle of the swash plate of the drive motor through electronic control.

Further, the drive motor is a hydraulically controlled motor, the first variable piston pump is driven by the power take-off of the chassis, and the hydraulic system also includes:

The first reversing valve is connected with the driving motor; when the hydraulic system is in the working state of the first displacement, the first reversing valve is in the first reversing position; when the hydraulic system is in the working state of the second displacement, the first reversing valve The valve is in the first initial position.

Further, the hydraulic system also includes a pressure reducing valve connected to the first reversing valve; and/or,

The first reversing valve is an air-operated reversing valve, or an electromagnetic reversing valve, or a manual reversing valve.

Further, the driving motor includes a first quantitative motor and a second quantitative motor; when the hydraulic system is in the first displacement operating state, the first quantitative motor and the second quantitative motor are connected in parallel, and the first quantitative motor and the second quantitative The motors are all in working condition;

Wherein, when the hydraulic system is in the working state of the second displacement, the second variable displacement plunger pump is at zero displacement, and the first variable displacement plunger pump is in the working state; or,

When the hydraulic system is in the working state of the second displacement, the second variable displacement plunger pump is connected in series with the first variable displacement plunger pump.

Furthermore, the first variable plunger pump is driven by the power take-off of the chassis, and the hydraulic system also includes:

The second reversing valve is connected with the second variable displacement plunger pump;

The third reversing valve, the second reversing valve and the second quantitative motor are all connected to the third reversing valve;

Wherein, when the hydraulic system is in the working state of the first displacement, the second reversing valve is in the second reversing position; when the hydraulic system is in the working state of the second displacement, the second reversing valve is in the second initial position, and the second reversing valve is in the second initial position The three-way reversing valve is in the third reversing position, so that the oil inlet port of the second quantitative motor communicates with the oil outlet port of the second quantitative motor.

Further, the second reversing valve is an air-operated reversing valve, or an electromagnetic reversing valve, or a manual reversing valve; and/or,

The third reversing valve is a hydraulic control reversing valve.

Furthermore, the first variable plunger pump is driven by the power take-off of the chassis, and the hydraulic system also includes:

The fourth reversing valve is connected with the second variable displacement plunger pump;

The fifth directional valve, the fourth directional valve, the first quantitative motor and the second quantitative motor are all connected to the fifth directional valve;

Wherein, when the hydraulic system is in the working state of the first displacement, the fourth reversing valve is in the fourth reversing position; when the hydraulic system is in the working state of the second displacement, the fourth reversing valve is in the fourth initial position, and the fourth reversing valve is in the fourth initial position. The fifth reversing valve is in the fifth initial position, so that the first quantitative motor and the second quantitative motor are connected in series through the adjustment of the fifth reversing valve.

Further, the hydraulic system also includes:

Hydraulic tank;

The first charge pump, the hydraulic oil tank and the first variable plunger pump are all connected to the first charge pump, and the first charge pump operates to generate suction to suck the hydraulic oil in the hydraulic oil tank into the oil suction port of the first variable plunger pump for replenishment. Oil;

The second charge pump, the hydraulic oil tank and the second variable plunger pump are all connected to the second charge pump, and the second charge pump operates to generate suction to suck the hydraulic oil in the hydraulic oil tank to the oil suction port of the second variable plunger pump for replenishment. Oil.

Further, the first variable displacement plunger pump is provided with a first relief valve, so that the oil entering the first variable displacement plunger pump overflows in the casing of the first variable displacement plunger pump through the first relief valve; and /or,

A second overflow valve is arranged in the second variable displacement plunger pump, so that the oil liquid entering the second variable displacement plunger pump overflows in the housing of the second variable displacement plunger pump through the second overflow valve.

According to another aspect of the present invention, a hydraulic control method is provided, the hydraulic control method adopts the hydraulic system provided above; the hydraulic control method includes: using the first driving part to drive the first variable displacement plunger pump to work, using the second driving part Drive the second variable plunger pump to work; drive the drive motor through the first variable plunger pump and/or the second variable plunger pump, and use the drive motor to drive the centrifugal pump; work according to the displacement of the hydraulic system The condition of the state controls the working condition of the first variable displacement plunger pump and the working condition of the second variable displacement plunger pump.

By applying the technical solution of the present invention, the working conditions of the first variable displacement plunger pump and the second variable displacement plunger pump are controlled according to the working state of the displacement of the hydraulic system. Specifically, the adjustment of the first driving part can facilitate the control of the working conditions of the first variable displacement plunger pump, and the adjustment of the second driving part can facilitate the control of the working conditions of the second variable displacement piston pump, so that It is convenient to reasonably control the driving conditions of the first driving part and the second driving part, so that one of the first driving part and the second driving part can be reasonably selected for driving during small-displacement operations, thereby effectively reducing the Driving needs to burn the amount of engine oil, so that energy consumption can be easily reduced, and energy saving and emission reduction and low carbon emission can be realized.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 shows a schematic diagram of a hydraulic system provided according to Embodiment 1 of the present invention;

Fig. 2 shows a schematic diagram of a hydraulic system provided according to Embodiment 2 of the present invention;

Fig. 3 shows a schematic diagram of a hydraulic system provided according to Embodiment 3 of the present invention;

Fig. 4 shows a schematic diagram of a hydraulic system according to Embodiment 4 of the present invention.

Wherein, the above-mentioned accompanying drawings include the following reference signs:

10. The first variable plunger pump;

20. Second variable plunger pump;

30. Drive motor; 31. First quantitative motor; 32. Second quantitative motor;

41. The first reversing valve; 42. The second reversing valve; 43. The third reversing valve; 44. The fourth reversing valve; 45. The fifth reversing valve;

50. Hydraulic oil tank;

60. Pressure gauge.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

As shown in Figures 1 to 4, the present invention provides a hydraulic system, which includes: a first variable displacement plunger pump 10 and a second variable displacement plunger pump 20, the first variable displacement plunger pump 10 is driven by the first part, the second variable displacement plunger pump 20 is driven by the second drive part; the drive motor 30, the drive motor 30 is used to drive the centrifugal pump, the first variable displacement plunger pump 10 and the second variable displacement plunger pump 20 are both Connected with the drive motor 30, the output oil of the first variable displacement piston pump 10 and/or the output oil of the second variable displacement piston pump 20 are used to drive the drive motor 30 to run; where the hydraulic system has different displacement operating states , and control the working conditions of the first variable displacement plunger pump and the second variable displacement piston pump according to the working state of the displacement of the hydraulic system.

With the hydraulic system provided by the invention, the working conditions of the first variable displacement plunger pump and the second variable displacement plunger pump are controlled according to the working state of the displacement of the hydraulic system. Specifically, the adjustment of the first driving part can facilitate the control of the working conditions of the first variable displacement plunger pump, and the adjustment of the second driving part can facilitate the control of the working conditions of the second variable displacement piston pump, so that It is convenient to reasonably control the driving conditions of the first driving part and the second driving part, so that one of the first driving part and the second driving part can be reasonably selected for driving during small-displacement operations, thereby effectively reducing the Driving needs to burn the amount of engine oil, so that energy consumption can be easily reduced, and energy saving and emission reduction and low carbon emission can be realized.

Specifically, the first driving part is a chassis vehicle, and the second driving part is a platform engine.

In this embodiment, the hydraulic system has a first displacement operation state and a second displacement operation state, and the displacement in the first displacement operation state is greater than that in the second displacement operation state; when the hydraulic system is in the first displacement When the hydraulic system is in the second displacement operation state, both the first variable displacement plunger pump 10 and the second variable displacement piston pump 20 are in the working state, and the working displacement of the drive motor 30 is kept at the maximum displacement; when the hydraulic system is in the second displacement operation state, the first variable displacement plunger pump 10 is in a non-working state, the second variable displacement plunger pump 20 is in a working state, and the working displacement of the driving motor 30 is reduced to a preset displacement.

By adopting the technical solution provided by the embodiment of the present invention, when working with a large displacement, the hydraulic system can be in the first displacement working state. When working in a small displacement, the hydraulic system can be in the second displacement working state. At this time, the first variable displacement plunger pump 10 can be in a non-working state. Correspondingly, there is no need to start the chassis, and at the same time, the centrifugal force is guaranteed. pump speed. In this way, when working with a small displacement, only the engine on the platform needs to work without starting the chassis, which can reduce fuel consumption; and because the engine on the platform also drives the centrifugal pump, the load on the engine on the platform is effectively increased The efficiency reduces the oil burning phenomenon of the engine on the platform, and realizes energy saving, emission reduction and low carbon emission. Therefore, adopting the hydraulic system provided by the present invention can solve the technical problem of high fuel consumption of the hydraulic system in the prior art when operating with a small displacement.

Specifically, the centrifugal pump in this embodiment may be a sand pump or a fracturing fluid pump.

In Embodiment 1 of the present invention, the drive motor 30 is a variable motor; when the hydraulic system is in the first displacement operating state, the swash plate inclination angle of the drive motor 30 is kept at the maximum displacement; when the hydraulic system is in the second displacement In the working state, the inclination angle of the swash plate of the driving motor 30 is adjusted to adjust the working displacement of the driving motor 30 to a preset displacement. With such an arrangement, it is convenient to adjust the working displacement of the driving motor 30 by adjusting the variables of the driving motor 30 .

Specifically, the driving motor 30 in this embodiment is an electronically controlled motor, and it can be understood that the driving motor 30 here is an electronically controlled variable motor. When the hydraulic system is in the working state of the first displacement, the electric control motor is in the power-off state; when the hydraulic system is in the working state of the second displacement, the electric control motor is in the power-on state, so that the electric control motor is driven by electronic control The inclination angle of the swash plate of the motor 30 is adjusted. In this way, control and adjustment are facilitated.

As shown in Figure 1, in this embodiment, the scheme of combining the hydraulic pump of the chassis vehicle and the hydraulic pump on the platform to drive the electronically controlled variable motor of the sand pump is adopted: the chassis vehicle drives the first variable-variable plunger pump 10 and the engine on the platform drives the second Variable displacement plunger pump 20, the first variable displacement plunger pump 10 has a first charge oil pump (the first charge oil pump is arranged inside the first variable displacement plunger pump 10 or outside the first variable displacement plunger pump 10), the second variable displacement plunger pump 20 has a second charge pump (the second charge pump is arranged in the second variable displacement plunger pump 20 or outside the second variable displacement plunger pump 20), the first charge pump and the second charge pump generate suction due to operation, and the hydraulic oil tank 50 The hydraulic oil reaches the oil suction port of the first variable displacement plunger pump 10 and the oil suction port of the second variable displacement plunger pump 20, replenishes the pipeline of the closed system, and then passes through the built-in first variable displacement piston pump 10 The relief valve overflows in the casing of the first variable displacement plunger pump 10, and overflows in the casing of the second variable displacement plunger pump 20 through the built-in second relief valve of the second variable displacement plunger pump 20, so as to respectively The rotating parts in the casing of the first variable displacement plunger pump 10 and the casing of the second variable displacement plunger pump 20 play the role of cooling, and then flow back into the hydraulic oil tank 50 .

When the control units of the first variable plunger pump 10 and the second variable plunger pump 20 receive signals, the hydraulic oil in the servo cylinder of the first variable plunger pump 10 will push the swash plate to move, and the second variable plunger pump 20 The hydraulic oil in the servo cylinder will push the swash plate to move, and because the inclination angle of the swash plate changes, the first variable displacement plunger pump 10 and the second variable displacement plunger pump 20 will have flow output, thereby driving the sand pump drive motor 30 to run .

When a large displacement is required for on-site operations, the chassis vehicle and the platform engine work at the same time, that is, the first variable piston pump 10 and the second variable piston pump 20 work at the same time, and the driving motor 30 adopts an electronically controlled variable motor, and the driving motor 30 does not Can get electricity, make the swash plate inclination angle of drive motor 30 keep on the maximum displacement, now drive motor 30 can drive sand pump operation with maximum power.

When the on-site operation requires a small displacement, the chassis vehicle does not work, that is, only the second variable piston pump 20 driven by the engine on the platform works, and the drive motor 30 will be powered at this time, so that the inclination angle of the swash plate of the drive motor 30 will change , adjust to the preset small displacement. Since the sand pump adopts the centrifugal pump method, the discharge volume at this time is small, so the input power of the sand pump is not large. At this time, a motor with a small displacement is used to make the sand The pump remains in a reasonable speed range. This reduces the use of the chassis engine, which can meet the application of reducing emissions and fuel economy in the field.

The functions and functions of each hydraulic component in this system: the hydraulic oil tank 50 provides the working medium for power transmission for the entire hydraulic system; the driving motor 30 is an executive mechanism, which uses an electronically controlled variable motor to convert pressure energy into mechanical energy; the first The variable displacement plunger pump 10 is a power element in the hydraulic system, which converts mechanical energy into pressure energy and transitions the working medium from a low pressure state to a high pressure state; the pressure gauge 60 displays the driving oil pressure during work; the second variable displacement plunger pump 20 is The power element in the hydraulic system converts mechanical energy into pressure energy and transitions the working medium from a low-pressure state to a high-pressure state.

In the second embodiment of the present invention, the driving motor 30 is a hydraulically controlled motor, and the first variable displacement plunger pump 10 is driven by the power take-off of the chassis vehicle. The hydraulic system also includes a first reversing valve 41, the first reversing valve 41 is connected with the drive motor 30; when the hydraulic system is in the first displacement operation state, the first reversing valve 41 is in the first reversing position; When the system is in the working state of the second displacement, the first reversing valve 41 is in the first initial position. With such an arrangement, the displacement can be adjusted adaptively by controlling the reversing of the first reversing valve 41 . In this embodiment, when the first reversing valve 41 is in the first initial position, the first reversing valve 41 does not reversing; when the first reversing valve 41 is in the first reversing position, the first reversing valve 41 Valve 41 switches direction.

Specifically, the hydraulic system further includes a pressure reducing valve, which is connected with the first reversing valve 41 . With such an arrangement, when the hydraulic system is in the working state of the second displacement, the pressure is reduced through the pressure relief valve.

Specifically, the first reversing valve 41 is an air-operated reversing valve, or an electromagnetic reversing valve, or a manual reversing valve.

As shown in Figure 2, it is the scheme of using the dual pumps of the chassis vehicle hydraulic pump and the platform hydraulic pump to drive the hydraulically controlled variable variable motor of the sand pump in the second embodiment: the chassis vehicle drives the first variable piston pump 10 and the platform engine drives the second variable displacement motor. Two variable plunger pumps 20, the first variable plunger pump 10 contains the first charge pump, the second variable plunger pump 20 contains the second charge pump, the first charge pump and the second charge pump generate suction due to operation, and the hydraulic oil tank 50 The hydraulic oil in the hydraulic oil reaches the oil suction port of the first variable piston pump 10 and the oil suction port of the second variable piston pump 20, replenishes the pipeline of the closed system, and then passes through the built-in first variable piston pump 10 An overflow valve overflows in the casing of the first variable displacement plunger pump 10, and overflows in the casing of the second variable displacement plunger pump 20 through the second overflow valve built in the second variable displacement plunger pump 20. The rotating components in the casing of the variable displacement plunger pump 10 and the rotating components in the casing of the second variable displacement plunger pump 20 play the role of cooling, and then flow back into the hydraulic oil tank 50 .

When the control units of the first variable displacement plunger pump 10 and the second variable displacement plunger pump 20 receive signals, the hydraulic oil in the servo cylinder of the first variable displacement plunger pump 10 will push the swash plate to move, and the second variable displacement plunger pump 20 will The hydraulic oil in the servo oil cylinder will push the swash plate to move, and because the inclination angle of the swash plate changes, the first variable piston pump 10 and the second variable auxiliary pump have flow output, thereby driving the sand pump drive motor 30 to run.

Since the hydraulic pump driven by the chassis vehicle adopts the method of the full-power power take-off of the chassis vehicle, when the full-power power take-off is hooked up, the air-controlled hook-up will be used, and the first reversing valve 41 at this time can use the air-controlled Control reversing valve (or electromagnetic reversing valve or manual reversing valve), that is, it can work with the air control valve of the PTO of the chassis vehicle at the same time, that is, when the chassis vehicle is working, when the full power take-off is connected, the first Once the reversing valve 41 will reversing together.

When a large displacement is required for on-site operations, the chassis truck and the platform engine work at the same time, that is, the first variable displacement plunger pump 10 and the second variable displacement plunger pump 20 work at the same time, the first reversing valve 41 performs reversing, and the sand pump drives The motor 30 adopts a hydraulically controlled variable motor, and the inclination angle of the swash plate of the sand pump driving motor 30 remains on the maximum displacement. At this time, the sand pump driving motor 30 can drive the sand pump to run with maximum power.

When the on-site operation needs a small displacement, the chassis car does not work, and the first reversing valve 41 is in the non-reversing position, so that the sand pump drive motor 30 swash plate inclination changes and is in a set small displacement state (also can Before the first reversing valve 41, a pressure reducing valve is added to depressurize to proportionally adjust the displacement of the sand pump drive motor 30), that is, only the second variable displacement plunger pump 20 driven by the engine on the platform works at this moment. Since the sand pump is a centrifugal pump, the discharge volume is small at this time, so the input power of the sand pump is not large. At this time, a motor with a small displacement is used to keep the sand pump in a reasonable speed range. This reduces the use of the chassis engine, which can meet the application of reducing emissions and fuel economy in the field.

The functions and functions of each hydraulic component in this system: the hydraulic oil tank 50 provides the working medium for power transmission for the entire hydraulic system;

The sand pump driving motor 30 is an actuator, which adopts a hydraulically controlled variable motor to convert pressure energy into mechanical energy. Transition from a low pressure state to a high pressure state; the pressure gauge 60 displays the driving oil pressure during work; the second variable plunger pump 20 is a power element in the hydraulic system, which converts mechanical energy into pressure energy and transitions the working medium from a low pressure state to a high pressure state State: Whether the first reversing valve 41 realizes whether the sand pump drive motor 30 is operating under a large displacement or a small displacement operation is switched and adjusted by reversing.

In Embodiment 3 of the present invention, the drive motor 30 includes a first quantitative motor 31 and a second quantitative motor 32; when the hydraulic system is in the first displacement operating state, the first quantitative motor 31 and the second quantitative motor 32 In parallel connection, both the first quantitative motor 31 and the second quantitative motor 32 are in working condition. Wherein, when the hydraulic system is in the working state of the second displacement, the second variable displacement plunger pump 20 is at zero displacement, and the first variable displacement plunger pump 10 is in the working state, so as to effectively adjust the displacement.

Specifically, the first variable displacement plunger pump 10 is driven by the power take-off of the chassis vehicle, the hydraulic system also includes a second reversing valve 42 and a third reversing valve 43, the second reversing valve 42 and the second variable displacement plunger Pump 20 is connected. Both the second reversing valve 42 and the second quantitative motor 32 are connected to the third reversing valve 43 . Wherein, when the hydraulic system is in the working state of the first displacement, the second reversing valve 42 is in the second reversing position; when the hydraulic system is in the working state of the second displacement, the second reversing valve 42 is in the second initial position , the third reversing valve 43 is in the third reversing position, so that the oil inlet port of the second quantitative motor 32 communicates with the oil outlet port of the second quantitative motor 32 . With such a setting, the adjustment method is simple and can be conveniently and effectively adjusted.

In this embodiment, the second reversing valve 42 is an air-operated reversing valve, or an electromagnetic reversing valve, or a manual reversing valve.

Specifically, the third reversing valve 43 in this embodiment is a hydraulically controlled reversing valve.

As shown in Figure 3, it is a scheme in which the chassis vehicle hydraulic pump and the platform hydraulic pump dual pumps are combined to drive two quantitative motors (the first quantitative motor 31 and the second quantitative motor 32) in the third embodiment: the chassis vehicle drives the first quantitative motor. A variable displacement plunger pump 10 and a platform engine drive a second variable displacement plunger pump 20, the first variable displacement plunger pump 10 contains a first charge pump, the second variable displacement plunger pump 20 contains a second charge pump, the first charge pump and The second charge pump generates suction due to its operation, and the hydraulic oil in the hydraulic oil tank 50 reaches the oil suction port of the first variable displacement plunger pump 10 and the oil suction port of the second variable displacement plunger pump 20 to replenish the pipeline of the closed system. Then the first relief valve built in the first variable displacement plunger pump 10 overflows in the casing of the first variable displacement plunger pump 10, and the second relief valve built in the second variable displacement plunger pump 20 overflows in the second displacement plunger pump. In the casing of the variable displacement plunger pump 20, the temperature of the rotating parts in the casing of the first variable displacement plunger pump 10 and the rotating parts in the casing of the first variable displacement plunger pump 10 are cooled, and then the flow returns to the hydraulic oil tank 50 in.

When the control units of the first variable displacement plunger pump 10 and the second variable displacement plunger pump 20 receive signals, the hydraulic oil in the servo cylinder of the first variable displacement plunger pump 10 will push the swash plate to move, and the second variable displacement plunger pump 20 will The hydraulic oil in the servo cylinder will push the swash plate to move, and because the inclination angle of the swash plate has changed, the first variable displacement plunger pump 10 and the second variable displacement piston pump 20 have flow output, so that the sand pump drive motor 30 runs ( The first quantitative motor 31 and the second quantitative motor 32 are mechanically connected to maintain synchronization).

Since the hydraulic pump driven by the chassis vehicle adopts the method of the full-power power take-off of the chassis vehicle, when the full-power power take-off is hooked up, air-controlled hooking will be used, and the reversing valve at this time can use air-controlled reversing The valve (or electromagnetic reversing valve or manual reversing valve) can work simultaneously with the air control valve of the power take-off of the chassis vehicle, that is, when the chassis vehicle is working, when the full power power take-off is connected, the reversing valve will Change directions together.

When a large displacement is required for on-site operations, the chassis vehicle and the platform engine work at the same time, that is, the first variable piston pump 10 and the second variable piston pump 20 work at the same time, the second reversing valve 42 performs reversing, and the first constant Quantitative motor 31 and second quantitative motor 32 are connected in parallel and both maintain on the maximum displacement. At this moment, both first quantitative motor 31 and second quantitative motor 32 can drive the sand pump with maximum power.

When the on-site operation needs a small displacement, when the chassis vehicle is not working, the second reversing valve 42 is in the non-reversing position. At this time, the third reversing valve 43 will reversing, so that the oil in and out of the second quantitative motor 32 The ports are connected to realize zero-displacement work. At this time, only the first quantitative motor 31 drives the sand pump, that is, only the second variable displacement plunger pump 20 driven by the engine on the platform works. Since the sand pump is a centrifugal pump, the discharge volume is small at this time, so the input power of the sand pump is not large. At this time, a motor with a small displacement is used to keep the sand pump in a reasonable speed range. This reduces the use of the chassis engine, which can meet the application of reducing emissions and fuel economy in the field.

The functions and functions of each hydraulic component in this system: the hydraulic oil tank 50 provides the working medium for power transmission for the entire hydraulic system; the first quantitative motor 31 is an actuator, which converts pressure energy into mechanical energy; the first variable plunger The pump 10 is a power element in the hydraulic system, which converts mechanical energy into pressure energy, and transitions the working medium from a low pressure state to a high pressure state; the pressure gauge 60 displays the driving oil pressure during work; the second variable plunger pump 20 is the hydraulic system. The power element converts mechanical energy into pressure energy, and transitions the working medium from a low-pressure state to a high-pressure state; the second reversing valve 42 controls the hydraulic control reversing valve to reversing through reversing. The third reversing valve 43 realizes whether the second quantitative motor 32 participates in the drive by reversing, so as to realize whether the equipment is operating under large displacement or small displacement; the second quantitative motor 32 is an actuator, which converts pressure energy into mechanical energy execution components.

In Embodiment 4 of the present invention, the drive motor 30 includes a first quantitative motor 31 and a second quantitative motor 32; when the hydraulic system is in the first displacement operating state, the first quantitative motor 31 and the second quantitative motor 32 In parallel connection, both the first quantitative motor 31 and the second quantitative motor 32 are in working condition. Wherein, when the hydraulic system is in the working state of the second displacement, the second variable displacement piston pump 20 is connected in series with the first variable displacement piston pump 10, so as to effectively adjust the displacement.

Specifically, the first variable displacement plunger pump 10 is driven by the power take-off of the chassis vehicle. The hydraulic system also includes a fourth reversing valve 44 and a fifth reversing valve 45. The fourth reversing valve 44 and the second variable displacement plunger The pump 20 is connected, and the fourth reversing valve 44 , the first quantitative motor 31 and the second quantitative motor 32 are all connected to the fifth reversing valve 45 . Wherein, when the hydraulic system is in the working state of the first displacement, the fourth reversing valve 44 is in the fourth reversing position; when the hydraulic system is in the working state of the second displacement, the fourth reversing valve 44 is in the fourth initial position , the fifth reversing valve 45 is in the fifth initial position, so that the first quantitative motor 31 and the second quantitative motor 32 are connected in series through the adjustment of the fifth reversing valve 45 . With such a setting, the adjustment method is simple and can be conveniently and effectively adjusted.

As shown in Figure 4, it is a scheme in which the chassis vehicle hydraulic pump and the platform hydraulic pump dual pumps are combined to drive two quantitative motors (the first quantitative motor 31 and the second quantitative motor 32) in the fourth embodiment: the chassis vehicle drives the first quantitative motor. A variable displacement plunger pump 10 and a platform engine drive a second variable displacement plunger pump 20, the first variable displacement plunger pump 10 contains a first charge pump, the second variable displacement plunger pump 20 contains a second charge pump, the first charge pump and The second charge pump generates suction due to its operation, and the hydraulic oil in the hydraulic oil tank 50 reaches the oil suction ports of the first variable displacement plunger pump 10 and the second variable displacement plunger pump 20 to replenish the pipeline of the closed system, and then passes through the second variable displacement plunger pump. The built-in charge relief valve of a variable displacement plunger pump 10 overflows in the housing of the first variable displacement plunger pump 10, and overflows in the second variable displacement plunger through the charge oil relief valve built in the second variable displacement plunger pump 20. The casing of the pump 20 cools down the rotating parts in the casing of the first variable displacement plunger pump 10 and the rotating parts in the casing of the first variable displacement plunger pump 10 , and then flows back into the hydraulic oil tank 50 .

When the control units of the first variable plunger pump 10 and the second variable plunger pump 20 receive signals, the hydraulic oil in the servo cylinder of the first variable plunger pump 10 will push the swash plate to move, and the second variable plunger pump 20 The hydraulic oil in the servo cylinder will push the swash plate to move, and because the inclination angle of the swash plate changes, the first variable displacement piston pump 10 and the second variable displacement piston pump 20 have flow output, so that the first quantitative motor 31 and the The second quantitative motor 32 operates synchronously (it is a double quantitative motor or two identical quantitative motors are connected by mechanical means to maintain synchronization).

Since the hydraulic pump driven by the chassis vehicle adopts the method of the full-power power take-off of the chassis vehicle, when the full-power power take-off is hooked up, air-controlled hooking will be used, and the reversing valve at this time can use air-controlled reversing valve (or electromagnetic reversing valve or manual reversing valve), that is, it works simultaneously with the air control valve of the PTO of the chassis vehicle, that is, when the chassis vehicle is working, when the full power PTO is connected, the reversing valve will Change directions together.

When a large displacement is required for on-site operations, the chassis vehicle and the engine on the platform work at the same time, that is, the first variable displacement piston pump 10 and the second variable displacement piston pump 20 work at the same time, the reversing valve performs reversing, and the double quantitative motor or two Two quantitative motors are connected in parallel to maintain the maximum displacement. At this time, the quantitative motor can drive the sand pump with maximum power.

When the on-site operation needs a small displacement, when the chassis vehicle is not working, the fourth directional valve 44 is in the non-reversing position, and the fifth directional valve 45 will not be reversing at this time, so that the double quantitative motor or two quantitative The oil port of the motor is connected in series to keep the minimum displacement to drive the sand pump, that is, only the second plunger pump driven by the engine on the platform works. Since the sand pump is a centrifugal pump, the discharge volume is small at this time, so the input power of the sand pump is not large. At this time, a motor with a small displacement is used to keep the sand pump in a reasonable speed range. This reduces the use of the chassis engine, which can meet the application of reducing emissions and fuel economy in the field.

The functions and functions of each hydraulic component in this system: the hydraulic oil tank 50 provides the working medium for power transmission for the entire hydraulic system; The executive component that converts pressure energy into mechanical energy; the first variable plunger pump 10 is the power element in the hydraulic system, which converts mechanical energy into pressure energy and transitions the working medium from a low pressure state to a high pressure state; the pressure gauge 60 shows the driving force during work. Oil pressure; the second variable displacement plunger pump 20 is a power element in the hydraulic system, which converts mechanical energy into pressure energy, and transitions the working medium from a low pressure state to a high pressure state; The fifth reversing valve 45 realizes whether the dual quantitative motor or two quantitative motors are connected in series or in parallel to participate in the drive through reversing, so as to keep the equipment operating under large displacement or small displacement;

In all the above-mentioned embodiments, the hydraulic system further includes a hydraulic oil tank 50, a first charge pump and a second charge pump. Both the hydraulic oil tank 50 and the first variable displacement plunger pump 10 are connected to the first charge pump, and the operation of the first charge pump generates suction to suck the hydraulic oil in the hydraulic oil tank 50 into the oil suction port of the first variable displacement plunger pump 10 for oil replenishment . Both the hydraulic oil tank 50 and the second variable displacement plunger pump 20 are connected to the second charge pump, and the operation of the second charge pump generates suction to suck the hydraulic oil in the hydraulic oil tank 50 into the oil suction port of the second variable displacement plunger pump 20 for oil replenishment .

Specifically, in all the above-mentioned embodiments, a first relief valve is provided in the first variable displacement plunger pump 10, so that the oil entering the first variable displacement plunger pump 10 overflows in the first displacement through the first relief valve. Inside the casing of the variable displacement plunger pump 10. The second variable displacement plunger pump 20 is provided with a second relief valve, so that the oil entering the second variable displacement plunger pump 20 overflows into the casing of the second variable displacement plunger pump 20 through the second relief valve.

Another embodiment of the present invention provides a hydraulic control method, which adopts the hydraulic systems provided in all the above-mentioned embodiments. The hydraulic control method includes: using the first driving part to drive the first variable displacement plunger pump to work, using the second driving part to drive the second variable displacement plunger pump to work; using the first variable displacement piston pump and/or the second variable displacement piston pump Drive the drive motor, and use the drive motor to drive the centrifugal pump; control the working conditions of the first variable piston pump and the second variable piston pump according to the displacement operating state of the hydraulic system .

From the above description, it can be seen that the above-mentioned embodiments of the present invention have achieved the following technical effects: the combination of dual hydraulic pumps or multiple hydraulic pumps, the use of variable motors or two or more motors connected in series or in parallel The combination method drives the sand pump of the sand mixing vehicle or the fracturing fluid discharge pump of the mixing vehicle separately, so that the chassis vehicle can stop working during small displacement construction operations on site, so as to achieve the effect of energy saving and emission reduction.

It should be noted that the terminology used here is only for describing specific implementations, and is not intended to limit the exemplary implementations according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations, means, components and/or combinations thereof.

The relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. At the same time, it should be understood that, for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the Authorized Specification. In all examples shown and discussed herein, any specific values should be construed as illustrative only, and not as limiting. Therefore, other examples of the exemplary embodiment may have different values. It should be noted that like numerals and letters denote like items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

In the description of the present application, it should be understood that orientation words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" etc. indicate the orientation Or positional relationship is generally based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description. In the absence of a contrary statement, these orientation words do not indicate or imply the device or element referred to It must have a specific orientation or be constructed and operated in a specific orientation, so it should not be construed as limiting the protection scope of the present application; the orientation words "inner and outer" refer to the inner and outer relative to the outline of each component itself.

For the convenience of description, spatially relative terms may be used here, such as "on ...", "over ...", "on the surface of ...", "above", etc., to describe The spatial positional relationship between one device or feature shown and other devices or features. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, devices described as "above" or "above" other devices or configurations would then be oriented "beneath" or "above" the other devices or configurations. under other devices or configurations". Thus, the exemplary term "above" can encompass both an orientation of "above" and "beneath". The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing corresponding components. To limit the protection scope of this application.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (13)

1. A hydraulic system, comprising:

a first variable displacement pump (10) and a second variable displacement pump (20), wherein the first variable displacement pump (10) is driven by a first driving part, and the second variable displacement pump (20) is driven by a second driving part;

the driving motor (30) is used for driving the centrifugal pump, the first variable plunger pump (10) and the second variable plunger pump (20) are connected with the driving motor (30), and the output oil of the first variable plunger pump (10) and/or the output oil of the second variable plunger pump (20) is used for driving the driving motor (30) to operate;

The hydraulic system is provided with different displacement working states, and the working conditions of the first variable plunger pump and the working conditions of the second variable plunger pump are controlled according to the conditions of the displacement working states of the hydraulic system.

2. The hydraulic system of claim 1, wherein the hydraulic system has a first displacement operating condition and a second displacement operating condition, the first displacement operating condition having a displacement greater than a displacement of the second displacement operating condition; when the hydraulic system is in the first displacement working state, the first variable displacement plunger pump (10) and the second variable displacement plunger pump (20) are both in working states, and the working displacement of the driving motor (30) is kept at the maximum displacement; when the hydraulic system is in the second displacement working state, the first variable displacement plunger pump (10) is in a non-working state, the second variable displacement plunger pump (20) is in a working state, and the working displacement of the driving motor (30) is reduced to a preset displacement.

3. The hydraulic system according to claim 2, characterized in that the drive motor (30) is a variable motor; maintaining a swash plate angle of the drive motor (30) at a maximum displacement when the hydraulic system is in the first displacement operating state; when the hydraulic system is in the second displacement working state, the inclination angle of the swash plate of the driving motor (30) is adjusted so as to adjust the working displacement of the driving motor (30) to a preset displacement.

4. A hydraulic system according to claim 3, characterized in that the drive motor (30) is an electric motor; when the hydraulic system is in the first displacement working state, the electric control motor is in a power-off state; when the hydraulic system is in the second displacement working state, the electric control motor is in an electric power-on state, so that the electric control motor can adjust the inclination angle of the swash plate of the driving motor (30) through electric control.

5. A hydraulic system according to claim 3, characterized in that the drive motor (30) is a pilot motor, the first variable displacement plunger pump (10) being driven by a power take-off of a chassis, the hydraulic system further comprising:

a first reversing valve (41) connected to the drive motor (30); -the first reversing valve (41) is in a first reversing position when the hydraulic system is in the first displacement operating state; the first reversing valve (41) is in a first initial position when the hydraulic system is in the second displacement operating state.

6. The hydraulic system of claim 5, wherein the hydraulic system is configured to,

the hydraulic system further comprises a pressure reducing valve connected with the first reversing valve (41); and/or the number of the groups of groups,

The first reversing valve (41) is a pneumatic reversing valve, an electromagnetic reversing valve or a manual reversing valve.

7. The hydraulic system according to claim 2, characterized in that the drive motor (30) comprises a first dosing motor (31) and a second dosing motor (32); when the hydraulic system is in the first displacement working state, the first quantitative motor (31) and the second quantitative motor (32) are connected in parallel, and the first quantitative motor (31) and the second quantitative motor (32) are both in working states;

wherein when the hydraulic system is in the second displacement working state, the second variable displacement plunger pump (20) is in zero displacement, and the first variable displacement plunger pump (10) is in a working state; or,

the second variable displacement plunger pump (20) is connected in series with the first variable displacement plunger pump (10) when the hydraulic system is in the second displacement operating state.

8. The hydraulic system according to claim 7, wherein the first variable displacement plunger pump (10) is driven by a power take-off of a chassis, the hydraulic system further comprising:

a second reversing valve (42) connected to the second variable displacement plunger pump (20);

a third directional valve (43), the second directional valve (42) and the second dosing motor (32) being connected to the third directional valve (43);

Wherein the second reversing valve (42) is in a second reversing position when the hydraulic system is in the first displacement operating state; when the hydraulic system is in the second displacement working state, the second reversing valve (42) is in a second initial position, and the third reversing valve (43) is in a third reversing position, so that the oil inlet of the second quantitative motor (32) is communicated with the oil outlet of the second quantitative motor (32).

9. The hydraulic system of claim 8, wherein the hydraulic system is configured to,

the second reversing valve (42) is a pneumatic reversing valve, an electromagnetic reversing valve or a manual reversing valve; and/or the number of the groups of groups,

the third reversing valve (43) is a hydraulic control reversing valve.

10. The hydraulic system according to claim 7, wherein the first variable displacement plunger pump (10) is driven by a power take-off of a chassis, the hydraulic system further comprising:

a fourth reversing valve (44) connected to the second variable displacement plunger pump (20);

a fifth directional valve (45), wherein the fourth directional valve (44), the first quantitative motor (31) and the second quantitative motor (32) are all connected with the fifth directional valve (45);

wherein the fourth reversing valve (44) is in a fourth reversing position when the hydraulic system is in the first displacement operating state; when the hydraulic system is in the second displacement working state, the fourth reversing valve (44) is in a fourth initial position, and the fifth reversing valve (45) is in a fifth initial position, so that the first metering motor (31) and the second metering motor (32) are connected in series through adjustment of the fifth reversing valve (45).

11. The hydraulic system according to any one of claims 1 to 10, characterized in that the hydraulic system further comprises:

a hydraulic oil tank (50);

the first oil supplementing pump is connected with the hydraulic oil tank (50) and the first variable plunger pump (10), and the first oil supplementing pump operates to generate suction so as to suck hydraulic oil in the hydraulic oil tank (50) into an oil suction port of the first variable plunger pump (10) for supplementing oil;

the hydraulic oil tank (50) and the second variable plunger pump (20) are connected with the second oil supplementing pump, and the second oil supplementing pump operates to generate suction so as to suck hydraulic oil in the hydraulic oil tank (50) into an oil suction port of the second variable plunger pump (20) for supplementing oil.

12. The hydraulic system of claim 11, wherein the hydraulic system is configured to,

a first overflow valve is arranged in the first variable plunger pump (10) so that oil entering the first variable plunger pump (10) overflows in a shell of the first variable plunger pump (10) through the first overflow valve; and/or the number of the groups of groups,

a second overflow valve is arranged in the second variable plunger pump (20) so that oil entering the second variable plunger pump (20) overflows in a shell of the second variable plunger pump (20) through the second overflow valve.

13. A hydraulic control method, characterized in that the hydraulic control method employs the hydraulic system according to any one of claims 1 to 12; the hydraulic control method includes:

the first variable plunger pump is driven to work by the first driving part, and the second variable plunger pump is driven to work by the second driving part;

driving a driving motor through the first variable plunger pump and/or the second variable plunger pump, and driving a centrifugal pump by adopting the driving motor;

and controlling the working conditions of the first variable plunger pump and the second variable plunger pump according to the condition of the displacement working state of the hydraulic system.