A constant flow pump split flow control hydraulic system, control method and crane

Abstract

The application discloses a kind of quantitative pump shunt control hydraulic system, control method and crane, the oil outlet of the oil tank is connected with quantitative pump oil inlet, the oil outlet of quantitative pump is connected with the oil inlet of center swivel body, the oil outlet of quantitative pump is also connected with the oil inlet A of shunt valve, the pressure sensing oil port p1 of the quantitative pump is connected with the non-spring cavity a port of shunt valve, the oil outlet B of the shunt valve is connected with the oil return port of oil tank, the oil outlet B of the center swivel body is connected with the oil inlet of main valve, the oil outlet a of the center swivel body is connected with the spring cavity b port of shunt valve, the pressure sensing oil port p2 of the main valve is connected with the feedback oil port b of center swivel body, the oil outlet of the main valve is connected with the oil inlet of actuating mechanism, the oil outlet of the actuating mechanism is connected with the oil return port of oil tank.The application solves the problem of multi-way valve shunt noise, improves user's perception, and reduces pressure loss, realizes energy saving.

Description

Technical Field

[0001] This invention relates to a quantitative pump diversion control hydraulic system, control method, and crane, belonging to the field of engineering machinery technology. Background Technology

[0002] Small and medium tonnage cranes generally use an engine-driven fixed displacement gear pump to supply oil to the hydraulic system. The output flow rate is determined by the engine speed. Under engine idling conditions, the output flow rate of the gear pump is basically constant.

[0003] To regulate the speed of the actuators, excess flow from the gear pump is typically diverted via a flow divider in a multi-way valve. These multi-way valves are usually located near the operator's cab. During minor or low-speed crane operations, a large amount of high-pressure oil is diverted through the multi-way valve, resulting in loud fluid diversion noise and a poor operator experience. This also leads to significant pressure loss and poor energy efficiency in existing hydraulic systems.

[0004] In addition, existing gear pumps with flow-dividing functions are generally used in steering systems. They achieve constant maximum flow control at high speeds by integrating a flow-dividing valve and setting a thin-walled orifice in the pump outlet oil passage to keep the pressure difference between the front and rear ends constant. However, this type of integrated pump can only control the maximum flow to remain constant through its internal structure and cannot adjust the flow rate delivered to the system in real time according to the needs of the external system.

[0005] Therefore, those skilled in the art urgently need to solve the problems of high noise and poor energy efficiency in existing quantitative gear pump systems, as well as the technical problems of single and fixed diversion devices. Summary of the Invention

[0006] Objective: In order to overcome the shortcomings of the existing technology, the present invention provides a quantitative pump diversion control hydraulic system, control method and crane.

[0007] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, a fixed displacement pump diversion control hydraulic system includes: an oil tank, a fixed displacement pump, a diversion valve, a central rotary body, a main valve, and a motor.

[0009] The oil tank outlet is connected to the metering pump inlet, the metering pump outlet is connected to the central rotating body inlet, the metering pump outlet is also connected to the diverter valve inlet A, the metering pump pressure sensing port p1 is connected to the diverter valve non-spring chamber a port, the diverter valve outlet B is connected to the oil tank return port, the central rotating body outlet B is connected to the main valve inlet, the central rotating body outlet a is connected to the diverter valve spring chamber b port, the main valve pressure sensing port p2 is connected to the central rotating body feedback port b, the main valve outlet is connected to the motor inlet, and the motor outlet is connected to the oil tank return port.

[0010] The pressure sensing port p1 of the metering pump is connected to the oil outlet of the metering pump, and the oil pressure of the pressure sensing port p1 is the same as that of the oil outlet.

[0011] The pressure sensing port p2 of the main valve is connected to the oil outlet of the main valve, and the oil pressure of the pressure sensing port p2 is the same as that of the oil outlet.

[0012] The diverter valve adjusts the valve core between the oil inlet A and the oil outlet B of the diverter valve 3 according to the pressure at the non-spring cavity a port and the spring cavity b port.

[0013] As a preferred embodiment, the diversion valve is located at the lower oil pump.

[0014] As a preferred embodiment, the diverter valve and the metering pump are integrated into one unit.

[0015] Secondly, a control method for a fixed displacement pump flow control hydraulic system includes the following steps:

[0016] When the fixed displacement pump diversion control hydraulic system is in standby mode, the valve core opening of the main valve is zero, the pressure of the load feedback pressure sensing port p2 is zero, and the pressure of the pressure sensing port p1 established by the flow rate output of the fixed displacement pump acts on the non-spring chamber a port of the diversion valve, pushing the spring open and opening the valve core of the diversion valve. The flow rate output by the fixed displacement pump flows back to the oil tank from the oil outlet B of the diversion valve, realizing the diversion of all oil to the oil tank.

[0017] As a preferred embodiment, the system further includes: when the fixed displacement pump diversion control hydraulic system starts working, as the main valve opens, the pressure of the load feedback pressure sensing port p2 is transmitted to the diversion valve and compared with the pressure of the fixed displacement pump output pressure sensing port p1. The diversion valve is controlled according to the pressure of the non-spring chamber a port and the spring chamber b port to push the valve core opening size between the inlet port A and the outlet port B of the diversion valve, so that the hydraulic oil output by the fixed displacement pump first supplies the flow demand of the main valve, and the excess flow is diverted back to the oil tank through the outlet port B of the diversion valve, thus achieving partial diversion.

[0018] As a preferred embodiment, the following is also included: when the flow rate output by the fixed displacement pump is less than or equal to the flow rate required by the main valve, the pressure of the pressure sensing port p1 of the fixed displacement pump is compared with the pressure of the load feedback pressure sensing port p2, and the flow divider valve is controlled not to divide the flow, so that all the flow rate output by the fixed displacement pump is supplied to the actuator.

[0019] Thirdly, a crane includes a fixed displacement pump diversion control hydraulic system as described in the first aspect, the hydraulic system comprising: an oil tank, a fixed displacement pump, a diversion valve, a central slewing body, a main valve, and a motor.

[0020] The oil tank outlet is connected to the metering pump inlet, the metering pump outlet is connected to the central rotating body inlet, the metering pump outlet is also connected to the diverter valve inlet A, the metering pump pressure sensing port p1 is connected to the diverter valve non-spring chamber a port, the diverter valve outlet B is connected to the oil tank return port, the central rotating body outlet B is connected to the main valve inlet, the central rotating body outlet a is connected to the diverter valve spring chamber b port, the main valve pressure sensing port p2 is connected to the central rotating body feedback port b, the main valve outlet is connected to the motor inlet, and the motor outlet is connected to the oil tank return port.

[0021] The pressure sensing port p1 of the metering pump is connected to the oil outlet of the metering pump, and the oil pressure of the pressure sensing port p1 is the same as that of the oil outlet.

[0022] The pressure sensing port p2 of the main valve is connected to the oil outlet of the main valve, and the oil pressure of the pressure sensing port p2 is the same as that of the oil outlet.

[0023] The diverter valve adjusts the valve core between the oil inlet A and the oil outlet B of the diverter valve 3 according to the pressure at the non-spring cavity a port and the spring cavity b port.

[0024] As a preferred embodiment, the diversion valve is located at the lower oil pump.

[0025] As a preferred embodiment, the diverter valve and the metering pump are integrated into one unit.

[0026] Beneficial effects: The present invention provides a quantitative pump diversion control hydraulic system, control method and crane, which solves the noise problem of multi-way valve diversion by arranging the diversion device at the lower oil pump, improves the user experience, reduces pressure loss and achieves energy saving. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the flow control hydraulic system of the present invention.

[0028] 1-Oil tank, 2-Metering pump, 3-Diverter valve, 4-Central rotating body, 5-Main valve, 6-Motor. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0030] The present invention will be further described below with reference to specific embodiments.

[0031] Example 1:

[0032] like Figure 1 As shown in the figure, this embodiment introduces a hydraulic system for controlling the flow of a fixed displacement pump, including: an oil tank 1, a fixed displacement pump 2, a flow divider valve 3, a central rotary body 4, a main valve 5, and a motor 6 (actuator).

[0033] The oil outlet of the oil tank 1 is connected to the oil inlet of the metering pump 2 via a pipeline. The oil outlet of the metering pump 2 is connected to the oil inlet A of the central rotating body 4 via a pipeline. The oil outlet of the metering pump 2 is also connected to the oil inlet A of the diverter valve 3 via a pipeline. The pressure sensing port p1 of the metering pump 2 is connected to the non-spring chamber a port of the diverter valve 3 via a pipeline. The oil outlet B of the diverter valve 3 is connected to the return port of the oil tank 1 via a pipeline. The central rotating body... The oil outlet B of the central rotating body 4 is connected to the oil inlet of the main valve 5 through a pipeline. The oil outlet a of the central rotating body 4 is connected to the spring chamber b of the diverter valve 3 through a pipeline. The pressure sensing oil port p2 of the main valve 5 is connected to the feedback oil port b of the central rotating body 4 through a pipeline. The oil outlet of the main valve 5 is connected to the oil inlet of the motor 6 (actuator) through a pipeline. The oil outlet of the motor 6 (actuator) is connected to the return oil port of the oil tank 1 through a pipeline.

[0034] The pressure sensing port p1 of the metering pump 2 is connected to the oil outlet of the metering pump 2, and the oil pressure of the pressure sensing port p1 is the same as that of the oil outlet.

[0035] The pressure sensing port p2 of the main valve 5 is connected to the oil outlet of the main valve 5, and the oil pressure of the pressure sensing port p2 is the same as that of the oil outlet.

[0036] The flow divider valve 3 adjusts the valve core between the oil inlet A and the oil outlet B according to the pressure at the non-spring cavity a port and the spring cavity b port.

[0037] Furthermore, the diversion valve 3 is located at the lower oil pump.

[0038] Furthermore, the diversion valve 3 and the metering pump 2 are integrated into one unit through a valve body design.

[0039] In another embodiment, the motor can be replaced by a hydraulic cylinder, with the oil outlet of the main valve 5 connected to the oil inlet of the hydraulic cylinder via a pipeline, and the oil outlet of the hydraulic cylinder connected to the oil return port of the oil tank 1 via a pipeline.

[0040] Since the hydraulic system of the present invention typically places the fixed displacement pump below the chassis platform of the engineering crane, and places the diversion device and the oil pump together on the undercarriage, the resulting diversion noise will not have a significant noise impact on the operator on the upper vehicle due to the blocking effect of the chassis structural components.

[0041] Meanwhile, excess flow from the fixed displacement pump is promptly diverted near the lower pump. Compared to diversion in the multi-way valve of the upper system, the hydraulic oil flows through fewer pipelines and components, resulting in less pressure loss and effectively reducing pump power loss, thus achieving good energy efficiency.

[0042] Example 2:

[0043] This embodiment describes a control method for a fixed displacement pump flow control hydraulic system, including the following steps:

[0044] Operating State 1: Standby Unloading. When the fixed displacement pump diversion control hydraulic system is in standby and not operating, the valve core opening of the main valve 5 is zero, and the pressure of the load feedback pressure sensing port p2 is zero. At this time, the pressure established by the flow rate output of the fixed displacement pump 2 at the pressure sensing port p1 acts on the non-spring chamber a port of the diversion valve 3, pushing the spring open and opening the valve core of the diversion valve 3. The flow rate output by the fixed displacement pump 2 flows back to the oil tank 1 from the oil outlet of the diversion valve 3, realizing the diversion of all oil to the oil tank 1.

[0045] Operating State 2: When the fixed displacement pump diversion control hydraulic system starts working, as the valve port of the main valve 5 opens, the pressure of the load feedback pressure sensing port p2 is transmitted to the diversion valve 3 and compared with the pressure of the pressure sensing port p1 output by the fixed displacement pump 2. The diversion valve 3 is controlled according to the pressure of the non-spring chamber a port and the spring chamber b port to push the valve core opening between the oil inlet A and the oil outlet B of the diversion valve 3, so that the hydraulic oil output by the fixed displacement pump 2 first supplies the flow demand of the main valve 5, and the excess flow is diverted back to the oil tank 1 through the oil outlet of the diversion valve 3, realizing partial diversion.

[0046] Operating state 3: When the flow rate output by the fixed displacement pump 2 is less than or equal to the flow rate required by the main valve 5, the pressure of the pressure sensing port p1 of the fixed displacement pump 2 is compared with the pressure of the load feedback pressure sensing port p2, and the flow divider valve 3 is controlled not to divide the flow, so that all the flow rate output by the fixed displacement pump 2 is supplied to the actuator (motor or cylinder).

[0047] The control method of the present invention sets the diversion valve 3 after the metering pump 2 and before the central rotating body 4, or integrates it with the metering pump. By comparing the load feedback pressure with the output pressure of the metering pump, the flow rate of the metering pump is controlled to supply the system on demand, thereby realizing the timely diversion function of the excess flow rate output by the metering pump.

[0048] Example 3:

[0049] This embodiment describes a crane, including a fixed displacement pump diversion control hydraulic system as described in Embodiment 1, comprising: an oil tank 1, a fixed displacement pump 2, a diversion valve 3, a central rotating body 4, a main valve 5, and a motor 6.

[0050] The oil outlet of the oil tank 1 is connected to the oil inlet of the fixed displacement pump 2 via a pipeline. The oil outlet of the fixed displacement pump 2 is connected to the oil inlet A of the central rotating body 4 via a pipeline. The oil outlet of the fixed displacement pump 2 is also connected to the oil inlet A of the diverter valve 3 via a pipeline. The pressure sensing port p1 of the fixed displacement pump 2 is connected to the non-spring chamber a port of the diverter valve 3 via a pipeline. The oil outlet B of the diverter valve 3 is connected to the return port of the oil tank 1 via a pipeline. The oil outlet B of the central rotating body 4 is connected to the oil inlet of the main valve 5 via a pipeline. The oil outlet a of the central rotating body 4 is connected to the spring chamber b port of the diverter valve 3 via a pipeline. The pressure sensing port p2 of the main valve 5 is connected to the feedback port b of the central rotating body 4 via a pipeline. The oil outlet of the main valve 5 is connected to the oil inlet of the motor 6 via a pipeline. The oil outlet of the motor 6 is connected to the return port of the oil tank 1 via a pipeline.

[0051] The pressure sensing port p1 of the metering pump 2 is connected to the oil outlet of the metering pump 2, and the oil pressure of the pressure sensing port p1 is the same as that of the oil outlet.

[0052] The pressure sensing port p2 of the main valve 5 is connected to the oil outlet of the main valve 5, and the oil pressure of the pressure sensing port p2 is the same as that of the oil outlet.

[0053] The flow divider valve 3 adjusts the valve core between the oil inlet A and the oil outlet B according to the pressure at the non-spring cavity a port and the spring cavity b port.

[0054] Furthermore, the diversion valve 3 is located at the lower oil pump.

[0055] Furthermore, the diversion valve 3 and the metering pump 2 are integrated into one unit through a valve body design.

[0056] In another embodiment, the motor can be replaced by a hydraulic cylinder, with the oil outlet of the main valve 5 connected to the oil inlet of the hydraulic cylinder via a pipeline, and the oil outlet of the hydraulic cylinder connected to the oil return port of the oil tank 1 via a pipeline.

[0057] Since the fixed displacement pump of the crane of the present invention is generally located below the platform of the engineering crane chassis, the flow diversion device and the oil pump are located together in the lower part of the crane. The resulting flow diversion noise will not have a significant noise impact on the operator on the upper part of the crane due to the blocking effect of the chassis structural components.

[0058] Meanwhile, excess flow from the fixed displacement pump is promptly diverted near the lower pump. Compared to diversion in the multi-way valve of the upper system, the hydraulic oil flows through fewer pipelines and components, resulting in less pressure loss and effectively reducing pump power loss, thus achieving good energy efficiency.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydraulic system for controlling the flow of a fixed displacement pump, characterized in that: include: Oil tank, metering pump, flow divider valve, central rotary body, main valve, and actuator; The oil tank outlet is connected to the metering pump inlet, the metering pump outlet is connected to the central rotating body inlet, the metering pump outlet is also connected to the diverter valve inlet A, the metering pump pressure sensing port p1 is connected to the diverter valve non-spring chamber a port, the diverter valve outlet B is connected to the oil tank return port, the central rotating body outlet B is connected to the main valve inlet, the central rotating body outlet a is connected to the diverter valve spring chamber b port, the main valve pressure sensing port p2 is connected to the central rotating body feedback port b, the main valve outlet is connected to the actuator inlet, and the actuator outlet is connected to the oil tank return port. The pressure sensing port p1 of the metering pump is connected to the oil outlet of the metering pump, and the oil pressure of the pressure sensing port p1 is the same as that of the oil outlet. The pressure sensing port p2 of the main valve is connected to the oil outlet of the main valve, and the oil pressure of the pressure sensing port p2 is the same as that of the oil outlet. The flow divider valve adjusts the valve core between the oil inlet A and the oil outlet B according to the pressure at the non-spring chamber a port and the spring chamber b port. The flow divider valve is located at the lower oil pump; The diverter valve and the metering pump are integrated into one unit.

2. The hydraulic system for flow control of a fixed displacement pump according to claim 1, characterized in that: The actuator is configured as a motor or a hydraulic cylinder.

3. A control method for a quantitative pump flow control hydraulic system according to any one of claims 1-2, characterized in that: The steps include the following: When the fixed displacement pump diversion control hydraulic system is in standby mode, the valve core opening of the main valve is zero, the pressure of the load feedback pressure sensing port p2 is zero, and the pressure of the pressure sensing port p1 established by the flow rate output of the fixed displacement pump acts on the non-spring chamber a port of the diversion valve, pushing the spring open and opening the valve core of the diversion valve. The flow rate output by the fixed displacement pump flows back to the oil tank from the oil outlet B of the diversion valve, realizing the diversion of all oil to the oil tank.

4. The control method according to claim 3, characterized in that: Also includes: When the fixed displacement pump diversion control hydraulic system starts working, as the main valve opens, the pressure at the load feedback pressure sensing port p2 is transmitted to the diversion valve and compared with the pressure at the fixed displacement pump output pressure sensing port p1. The diversion valve is controlled according to the pressure at the non-spring chamber a port and the spring chamber b port to adjust the valve core opening size between the inlet port A and the outlet port B of the diversion valve. This allows the hydraulic oil output from the fixed displacement pump to first supply the flow demand of the main valve, and the excess flow is diverted back to the oil tank through the outlet port B of the diversion valve, thus achieving partial diversion.

5. The control method according to claim 3, characterized in that: Also includes: When the flow rate output by the fixed displacement pump is less than or equal to the flow rate required by the main valve, the pressure at the pressure sensing port p1 of the fixed displacement pump is compared with the pressure at the load feedback pressure sensing port p2. The flow divider valve is controlled not to divide the flow, and all the flow rate output by the fixed displacement pump is supplied to the actuator.

6. A crane, characterized in that: The present invention includes a fixed displacement pump diversion control hydraulic system, the hydraulic system comprising: an oil tank, a fixed displacement pump, a diversion valve, a central rotary body, a main valve, and an actuator; The oil tank outlet is connected to the metering pump inlet, the metering pump outlet is connected to the central rotating body inlet, the metering pump outlet is also connected to the diverter valve inlet A, the metering pump pressure sensing port p1 is connected to the diverter valve non-spring chamber a port, the diverter valve outlet B is connected to the oil tank return port, the central rotating body outlet B is connected to the main valve inlet, the central rotating body outlet a is connected to the diverter valve spring chamber b port, the main valve pressure sensing port p2 is connected to the central rotating body feedback port b, the main valve outlet is connected to the actuator inlet, and the actuator outlet is connected to the oil tank return port. The pressure sensing port p1 of the metering pump is connected to the oil outlet of the metering pump, and the oil pressure of the pressure sensing port p1 is the same as that of the oil outlet. The pressure sensing port p2 of the main valve is connected to the oil outlet of the main valve, and the oil pressure of the pressure sensing port p2 is the same as that of the oil outlet. The flow divider valve adjusts the valve core between the oil inlet A and the oil outlet B according to the pressure at the non-spring chamber a port and the spring chamber b port. The flow divider valve is located at the lower oil pump; The diverter valve and the metering pump are integrated into one unit.

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