阅读说明：本技术 回油压力连续可调的负载口独立控制系统 (Independent control system for load port with continuously adjustable oil return pressure ) 是由 丁孺琦 熊文杰 程敏 胡国良 李刚 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种回油压力连续可调的负载口独立控制系统,包括液压动力源、油箱、负载口独立控制阀组、液压执行器、控制器和控制手柄。该负载口独立控制系统通过在回油路上增加一个压力可调的电比例溢流阀同时并联一个单向阀的方式,达到调节回油路背腔压力,并自适应流量需求的目的,进而解决了传统负载口独立控制系统在低压再生模式下,液压执行器的低压腔产生气穴现象的问题,同时也使得系统在普通模式下,不会因过大的背腔压力产生不必要的压力损失。(The invention discloses a load port independent control system with continuously adjustable oil return pressure. This load mouth independent control system reaches the back of the body chamber pressure of adjusting oil return way through the mode that increases a pressure adjustable electric proportion overflow valve and parallelly connected a check valve simultaneously on the oil return way to the purpose of self-adaptation flow demand, and then solved traditional load mouth independent control system under the low pressure regeneration mode, the problem that hydraulic actuator's low pressure chamber produced cavitation, also make the system simultaneously under ordinary mode, can not produce unnecessary loss of pressure because of too big back of the body chamber pressure.)

1. The utility model provides a return oil pressure continuously adjustable's load mouth independent control system which characterized in that includes:

the hydraulic power source (1) is used for providing required flow for the system;

the oil tank (2) is used for storing hydraulic oil required by the system;

a controller (3) for providing control signals to the system;

the load port independent control valve group (4) is used for changing a hydraulic circuit of a system to enable an actuator to work in a required working mode, comprises a first proportional direction valve (41) and a second proportional direction valve (42), and is characterized in that an electric proportional overflow valve (43) is additionally arranged on an oil return path between the first proportional direction valve (41) and the second proportional direction valve (42) and is connected with a one-way valve (44) in parallel at the same time, and the oil return pressure is adjusted to avoid cavitation; the set oil return pressure of the electric proportional overflow valve (43) is adjusted according to the following formula:

in the formula, q_v2For the actual flow through the second proportional directional valve (42), K_vIs the flow pressure coefficient, p, of the first proportional directional valve (41) and the second proportional directional valve (42)_rIs the return pressure between the first proportional directional valve (41) and the second proportional directional valve (42), p_cIs the pressure threshold for cavitation.

The hydraulic actuator (5) is used for converting the energy provided by the hydraulic power source (1) into mechanical energy to realize the operation required actually;

the control handle (6) is used for inputting a speed signal to the controller (3), and the controller (3) is used for controlling the first proportional directional valve (41) and the second proportional directional valve (42) so as to control the action of the hydraulic actuator (5).

2. The load port independent control system with continuously adjustable return oil pressure as claimed in claim 1, wherein an oil outlet of the hydraulic power source (1) is connected with an oil inlet P of the load port independent control valve group (4) through a pipeline, and an oil return port T of the load port independent control valve group (4) is connected with the oil tank (2) through a pipeline; a first working oil port A of the load port independent control valve group (4) is connected with a rodless cavity of the hydraulic actuator (5) through a pipeline, and a second working oil port B of the load port independent control valve group (4) is connected with a rod cavity of the hydraulic actuator (5) through a pipeline; the load port independent control valve group (4) is connected with the controller (3) through an electric circuit, and the control handle (6) is communicated with the controller (3) through the electric circuit.

3. The load port independent control system with continuously adjustable oil return pressure as claimed in claim 2, characterized in that the load port independent control valve group (4) comprises a first proportional directional valve (41), a second proportional directional valve (42), an electric proportional overflow valve (43), a working port A pressure sensor (46), a working port B pressure sensor (45) and a check valve (44); the first proportional directional valve (41) comprises an oil inlet P1, an oil return port T1 and an oil outlet A1, the second proportional directional valve (42) comprises an oil inlet P2, an oil return port T2 and an oil outlet A2, wherein the oil inlet P1 of the first proportional directional valve (41) is connected with the oil inlet P2 of the second proportional directional valve (42) and is connected with the oil inlet P of the load port independent control valve group (4), the oil outlet A1 of the first proportional directional valve (41) and the oil inlets of the pressure sensors (46) of the first working oil port A are connected with the first working oil port A of the load port independent control valve group (4), the oil outlet A2 of the second proportional directional valve (42) and the oil inlets of the pressure sensors (45) of the second working oil port B are connected with the second working oil port B of the load port independent control valve group (4), and the oil return ports T54 of the first proportional directional valve (41) and the second proportional directional valve (42) are connected with the oil return port T1), T2 are connected with each other and are connected with the oil outlet of the electric proportional overflow valve (43) and the oil outlet of the check valve (44), and the oil inlet of the electric proportional overflow valve (43) and the oil inlet of the check valve (44) are connected with the oil return port T of the load port independent control valve group (4).

4. The load port independent control system with the continuously adjustable return oil pressure as claimed in any one of claims 1-3, characterized in that when the system is in a low-pressure regeneration mode, two cavities of the hydraulic actuator (5) are simultaneously communicated with a low-pressure return oil circuit to form a differential connection, and the system can suck oil from the oil tank (2) at the moment, and air cavities are avoided by adjusting the pressure of an electric proportional overflow valve (43) on the return oil circuit and a parallel one-way valve (44); when the system is in a low-pressure retraction regeneration mode, the set pressure of the electric proportional overflow valve (43) can be matched with the flow of the second proportional directional valve (42) for self-adaptive adjustment, so that required oil return back pressure is provided, and cavitation of a low-pressure cavity of the hydraulic actuator (5) is avoided; when the system is in a low-pressure extension regeneration mode, the system needs to absorb extra flow from oil return of an oil tank (2) or other actuators to meet the flow demand, and the system can provide required flow and ensure certain pressure of an oil return path no matter absorbs other actuators and returns oil through an overflow valve or absorbs flow from the oil tank through a one-way valve (44), so that cavitation of a low-pressure cavity of a hydraulic actuator (5) is avoided; when the system is in a common working mode, the set pressure of the electric proportional overflow valve (43) is adjusted to be nearly zero, so that the pressure loss of oil when the oil returns to the oil tank (2) through the electric proportional overflow valve (43) is reduced.

Technical Field

The invention relates to the technical field of hydraulic transmission and control, in particular to an independent control system for a load port with continuously adjustable return oil pressure.

Background

The load port independent control system can break the restriction of coupling adjustment of the inlet valve port and the outlet valve port, so that the system can be switched to a hydraulic loop with better energy consumption according to different working condition modes of the actuator, the control freedom degree of the system can be increased, and multi-target control such as motion control, energy-saving control and the like of the system can be realized. When the load of the actuator is an overrunning load, the load port independent control system works in a low-pressure regeneration mode, the inlet and the outlet of the hydraulic actuator are simultaneously communicated with a low-pressure oil return path to form differential connection, and the hydraulic actuator drives the actuator to move through the overrunning load at the moment without providing flow by a pump. Although the system saves energy in this mode, cavitation is likely to occur through on-way pressure losses and valve port pressure losses as the return oil passes through the control valve into the hydraulic actuator low pressure chamber. To solve this problem, a check valve is usually added to the return line to increase the back pressure, and the opening pressure of the check valve determines the return pressure. Although the problem of cavitation is solved to a certain extent in this way, the adaptability of the check valve is poor because the pressure loss increases with the increase of the flow rate, so that the low-pressure regeneration modes with different flow rates require check valves with different back pressures. If a higher cracking pressure check valve is selected to meet different low pressure regeneration flow requirements, then a greater pressure loss will result due to the excess back cavity pressure in the return line.

Therefore, in order to solve the problem that cavitation is easy to occur when the system works in a low-pressure regeneration mode and simultaneously avoid the system from generating large pressure loss in a common mode, the invention provides an independent control system for a load port, and the return oil pressure of the independent control system can be continuously adjusted.

Disclosure of Invention

The invention aims to provide a load port independent control system with continuously adjustable return oil pressure aiming at the defects of the prior art.

The purpose of the invention is realized by the following technical scheme: a return oil pressure continuously adjustable load port independent control system, comprising:

the hydraulic power source is used for providing required flow for the system;

the oil tank is used for storing hydraulic oil required by the system;

a controller for providing a control signal to the system;

the load port independent control valve group is used for changing a hydraulic circuit of the system, so that the actuator can work in a required working mode, comprises a first proportional direction valve and a second proportional direction valve, an electric proportional overflow valve is added on an oil return path between the first proportional direction valve and the second proportional direction valve, and is connected with a check valve in parallel, and the oil return pressure is adjusted to avoid cavitation; the set oil return pressure of the electric proportional overflow valve is adjusted according to the following formula:

in the formula, q_v2For the actual flow through the second proportional directional valve, K_vIs the flow pressure coefficient, p, of the first proportional directional valve and the second proportional directional valve_rIs the return pressure between the first and second proportional directional valves, p_cIs the pressure threshold for cavitation.

The hydraulic actuator is used for converting the energy provided by the hydraulic power source into mechanical energy to realize the operation required actually;

the control handle is used for inputting a speed signal to the controller, and the controller controls the first proportional direction valve and the second proportional direction valve so as to control the action of the hydraulic actuator.

Furthermore, an oil outlet of the hydraulic power source is connected with an oil inlet P of the load port independent control valve group through a pipeline, and an oil return port T of the load port independent control valve group is connected with an oil tank through a pipeline; a first working oil port A of the load port independent control valve group is connected with a rodless cavity of the hydraulic actuator through a pipeline, and a second working oil port B of the load port independent control valve group is connected with a rod cavity of the hydraulic actuator through a pipeline; the load port independent control valve group is connected with the controller through an electric circuit, and the control handle is communicated with the controller through the electric circuit.

Furthermore, the load port independent control valve group comprises a first proportional direction valve, a second proportional direction valve, an electric proportional overflow valve, a working port A pressure sensor, a working port B pressure sensor and a one-way valve; the first proportional directional valve comprises an oil inlet P1, an oil return port T1 and an oil outlet A1, the second proportional directional valve comprises an oil inlet P2, an oil return port T2 and an oil outlet A2, wherein the oil inlet P1 of the first proportional directional valve and the oil inlet P2 of the second proportional directional valve are connected with each other and are connected with the oil inlet P of the load port independent control valve group, the oil outlet A1 of the first proportional directional valve and the oil inlet of the pressure sensor of the first working oil port A are connected with the first working oil port A of the load port independent control valve group, the oil inlets of the pressure sensor of the oil outlet A2 of the second proportional directional valve and the oil inlet of the pressure sensor of the second working oil port B are connected with the second working oil port B of the load port independent control valve group, the oil return ports T1 and T2 of the first proportional directional valve and the second proportional directional valve are connected with each other and are connected with the oil outlets of the electric proportional overflow valve and the one-way valve, and an oil inlet of the electric proportional overflow valve and an oil inlet of the check valve are connected with an oil return port T of the load port independent control valve group.

Furthermore, when the system is in a low-pressure regeneration mode, two cavities of the hydraulic actuator are simultaneously communicated with a low-pressure oil return circuit to form differential connection, the system can absorb oil from an oil tank, and oil passes through a pipeline and a proportional directional valve to generate certain pressure loss, so that the pressure loss causes the pressure of the low-pressure cavity of the hydraulic actuator to be too low, and then the problem of air cavity is caused, and the air cavity is avoided by adjusting the pressure of an electric proportional overflow valve on the oil return circuit and a one-way valve connected in parallel; when the system is in a low-pressure retraction regeneration mode, the set pressure of the electric proportional overflow valve can be matched with the flow of the second proportional directional valve for self-adaptive adjustment, so that required oil return back pressure is provided, and the generation of cavitation in a low-pressure cavity of the hydraulic actuator is avoided; when the system is in a low-pressure extension regeneration mode, the system needs to absorb extra flow from oil return of an oil tank or other actuators to meet the flow demand, and the system can provide the required flow and ensure certain pressure of an oil return path no matter absorbs other actuators and returns oil through an overflow valve or absorbs flow from the oil tank through a one-way valve, so that cavitation of a low-pressure cavity of the hydraulic actuator is avoided; when the system is in a common working mode, if the pressure of the back cavity is overlarge, larger pressure loss can be caused, so that the set pressure of the electric proportional overflow valve is adjusted to be nearly zero, and the pressure loss of oil when the oil returns to the oil tank through the electric proportional overflow valve is reduced.

The invention has the beneficial effects that:

(1) according to the invention, the overflow valve is additionally arranged on the oil return path of the system, so that the oil return pressure in a low-pressure regeneration mode is improved, and the problem of air cavity is prevented.

(2) The overflow valve added in the invention adopts proportional control, and when the system is in a low-pressure regeneration mode, the system can be adaptively adjusted according to pressure loss generated by different flows; when the system is in the normal mode, the return oil pressure can be reduced to the lowest value, so that the pressure loss of the system is reduced, and the energy consumption of the system is reduced.

Drawings

FIG. 1 is a system schematic diagram of the load port independent control system with continuously adjustable return oil pressure according to the present invention.

Fig. 2 is a schematic diagram of the load port independent control valve bank of the present invention.

FIG. 3 is a schematic diagram of the low pressure retract regeneration mode of the present invention.

FIG. 4 is a schematic diagram of the low pressure extend regeneration mode of the present invention.

Fig. 5 is a schematic diagram of the impedance extension mode of the present invention.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Referring to fig. 1, the invention provides an independent control system for a load port with continuously adjustable return oil pressure, comprising:

the hydraulic power source 1 is used for providing required flow for the system; the oil tank 2 is used for storing hydraulic oil required by the system; the controller 3 is used for providing a control signal for the system; the hydraulic actuator 5 is used for converting the energy provided by the hydraulic power source 1 into mechanical energy to realize actually required operations, such as lifting movement of a mechanical arm of an excavator; the control handle 6 is used for inputting a speed signal to the controller 3, and the controller 3 controls the first proportional directional valve 41 and the second proportional directional valve 42, so as to control the action of the hydraulic actuator 5.

The load port independent control valve group 4 is used for changing a hydraulic circuit of a system, so that an actuator can work in a required working mode, and comprises a first proportional direction valve 41 and a second proportional direction valve 42, an electric proportional overflow valve 43 is added on an oil return path between the first proportional direction valve 41 and the second proportional direction valve 42, and is connected with a check valve 44 in parallel, and the oil return pressure is adjusted to avoid air pockets;

an oil outlet of the hydraulic power source 1 is connected with an oil inlet P of the load port independent control valve group 4 through a pipeline, and an oil return port T of the load port independent control valve group 4 is connected with the oil tank 2 through a pipeline; a first working oil port A of the load port independent control valve group 4 is connected with a rodless cavity of the hydraulic actuator 5 through a pipeline, and a second working oil port B of the load port independent control valve group 4 is connected with a rod cavity of the hydraulic actuator 5 through a pipeline; the load port independent control valve group 4 is connected with the controller 3 through an electric circuit, and the control handle 6 is communicated with the controller 3 through the electric circuit.

Referring to fig. 2, the load port independent control valve group 4 includes a first proportional directional valve 41, a second proportional directional valve 42, an electric proportional relief valve 43, a pressure sensor 44 of a first working port a, and a pressure sensor 45 of a second working port B. The first proportional directional valve 41 comprises an oil inlet P1, an oil return port T1 and an oil outlet a1, the second proportional directional valve 42 comprises an oil inlet P2, an oil return port T2 and an oil outlet a2, wherein the oil inlet P1 of the first proportional directional valve 41 and the oil inlet P2 of the second proportional directional valve 42 are connected with each other and are connected with the oil inlet P of the load port independent control valve group 4, the oil outlet a1 of the first proportional directional valve 41 and the oil inlet of the pressure sensor 44 of the first working port a are connected with the first working port a of the load port independent control valve group 4, the oil outlet a2 of the second proportional directional valve 42 and the oil inlet of the pressure sensor 45 of the second working port B are connected with the second working port B of the load port independent control valve group 4, the oil return ports T1 and T2 of the first proportional directional valve 41 and the second proportional directional valve 42 are connected with each other and are connected with the oil outlet of the electric proportional overflow valve 43 and the check valve 44, an oil inlet of the electric proportional overflow valve 43 and an oil inlet of the check valve 44 are connected with an oil return port T of the load port independent control valve group 4.

The load port independent control system with the continuously adjustable oil return pressure comprises seven working modes. In a common mode, the system can work in four modes of resistance extension, resistance retraction, overrunning extension and overrunning retraction; in the regeneration mode, the system can work in three modes of high-pressure extension regeneration, low-pressure retraction regeneration and low-pressure extension regeneration.

The embodiment of the invention takes the low-pressure retraction regeneration mode and the low-pressure extension regeneration mode as an example; when the system is in the normal mode, the impedance extension mode is taken as an example, and other normal operation modes are similar.

Referring to fig. 3, the first proportional directional valve 41 and the second proportional directional valve 42 of the load port independent control valve group 4 are both powered on right, the rodless cavity and the rod cavity of the hydraulic actuator 5 are simultaneously communicated with a low-pressure oil return path, the piston rod of the hydraulic actuator 5 is driven to retract by exceeding the load, at this time, the oil acts on the pressure generated by the actuator by the load and flows from the rodless cavity to the rod cavity of the hydraulic actuator, and no pump is needed to provide extra flow. At this time, the set pressure of the electric proportional relief valve 43 is adaptively adjusted according to the magnitude of the flow rate passing through the second proportional directional valve 42, thereby preventing cavitation in the rod chamber of the hydraulic actuator 5. The set oil return pressure of the electric proportional relief valve 43 is adjusted according to the following formula:

in the formula, q_v2For the actual flow through the second proportional directional valve 42, K_vIs the flow pressure coefficient, p, of the first and second proportional directional valves 41 and 42_rIs the return pressure between the first and second proportional directional valves 41 and 42, p_cPressure threshold for cavitation

Referring to fig. 4, the first proportional directional valve 41 and the second proportional directional valve 42 of the load port independent control valve group 4 are both powered on right, the rodless cavity and the rod cavity of the hydraulic actuator 5 are simultaneously communicated with a low-pressure oil return path, and the hydraulic actuator 5 is driven to extend beyond a load, at this time, the oil flows from the rod cavity to the rodless cavity of the hydraulic actuator by the pressure generated by the action of the load on the actuator, the pump is not required to provide flow, and the system needs to obtain a certain extra flow. If the system is a multi-actuator system, the required extra flow can be sucked from other actuators in an oil return mode and returns oil through the electric proportional overflow valve 43, and the set pressure of the electric proportional overflow valve 43 is adaptively adjusted along with the flow passing through the first proportional directional valve 41; if the system is a single actuator system, oil is drawn from the tank through a check valve 44 to meet the desired flow. No matter other actuators are sucked and return oil is returned through the electric proportional overflow valve 43, or flow is sucked from the oil tank through the check valve 44, the required flow can be provided, certain return oil pressure is ensured, and cavitation is prevented from being generated in a rodless cavity of the hydraulic actuator 5.

Referring to fig. 5, the first proportional direction valve 41 of the load port independent control valve group 4 is energized from the left, the second proportional direction valve 42 is energized from the right, the rodless cavity of the hydraulic actuator 5 is communicated with high-pressure oil of the pump, the rod cavity is communicated with a low-pressure oil return path, and the piston rod of the hydraulic actuator 5 extends out to push the load. At this time, the electric proportional relief valve 43 adjusts the set pressure to a nearly zero value to reduce the pressure loss generated when the oil returns to the tank.

The above-described embodiments are intended to illustrate rather than to limit the invention, and any modifications and variations of the present invention are within the spirit of the invention and the scope of the appended claims.