Load feedback pressure stabilizing selector valve

Abstract

The invention discloses a load feedback pressure stabilizing selector valve which comprises a valve body, a plurality of oil inlets connected with an executing mechanism are formed in the valve body, a main oil way LS communicated with a variable pump is arranged in the valve body, the main oil way LS is communicated with an oil way LS1, an oil way LS2 and an oil way LS3, a shuttle valve for selecting and transmitting oil with the highest pressure is arranged at the intersection of the oil way LS1, the oil way LS2 and the oil way LS3, the oil way LS1 is communicated with an energy accumulator for dynamic pressure stabilization, and the oil way LS3 is communicated with an energy accumulator for dynamic pressure stabilization. Wherein the shuttle valve is responsible for selecting and transmitting a pressure signal, namely, the stable pressure supply of the variable pump is realized when the load pressure is rapidly changed by comparing the highest pressure oil among an LS1 oil path, an LS2 oil path and an LS3 oil path and conveying the highest pressure oil to the variable pump and adjusting the required output pressure of the variable pump and when the pressure of a main oil path LS is suddenly increased, the energy accumulator is filled with liquid, the pressure is suddenly reduced and the energy accumulator discharges liquid.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydraulic control, and particularly relates to a load feedback pressure stabilizing selection valve. BACKGROUND

[0002] The telescopic arm forklift is a multifunctional engineering mechanical equipment combining the functions of a forklift, a crane and an aerial work platform, and is widely applied to fields such as construction, agriculture, logistics, ports and mining. Typical application scenarios include high-altitude material handling, bale handling, container loading and unloading, heavy equipment maintenance and rescue, etc. The rich application scenarios require the telescopic arm forklift to be able to perform various actions such as telescoping, amplitude changing and overturning according to different working condition requirements. The load of each action is different, but the speed of each action needs to be independently controlled and kept stable. However, impact and oscillation often occur in the working of the traditional load feedback system. To solve this problem, a new type of load feedback system needs to be designed.

[0003] The load feedback pressure stabilizing selection valve can provide the highest load pressure signal to the pump, thereby realizing independent speed regulation of multiple actuators. In this load feedback scheme, when the load pressures of multiple actuators change rapidly, the total oil line LS needs to frequently switch the highest load signal, at which time the one-way pump frequently adjusts the output pressure, which may cause pressure oscillation. Secondly, when the load pressures of two actuators are very close (the difference is less than the opening pressure of the one-way valve), the two one-way valves may alternately open and close, which may also cause the output pressure of the variable pump to fluctuate. SUMMARY

[0004] The purpose of the present application is to provide a load feedback pressure stabilizing selection valve that can reduce pressure oscillation and fluctuation.

[0005] Technical solution: The load feedback pressure stabilizing selection valve comprises a valve body, an oil inlet connected to an actuator and an oil outlet connected to a variable pump are arranged on the valve body, the oil outlet oil line is connected to each oil inlet oil line, a shuttle valve for controlling the delivery of the highest pressure oil to the variable pump is arranged at the intersection of the oil inlet oil lines, and an accumulator for charging or discharging is connected to the oil inlet oil line.

[0006] The shuttle valve is a three-way structure.

[0007] Further, the three-way structure comprises a valve core for controlling the flow of pressure oil.

[0008] The first oil inlet is connected to a main valve.

[0009] The second oil inlet is connected to a brake valve.

[0010] The third oil inlet is connected to a steering gear.

[0011] The accumulator is fixed to the valve body.

[0012] This invention achieves dynamic pressure stabilization by adding an accumulator and a shuttle valve to a traditional load feedback system. The accumulator acts as a "shock absorber" for active pressure stabilization, and the shuttle valve is used for pressure signal selection. By comparing the highest pressures in each check valve circuit, the highest pressure signal is selected and transmitted to the variable pump. The variable pump then adjusts the required output pressure, achieving dynamic pressure stabilization. The hydraulic control valve with pressure stabilization and selection functions is a key component for realizing the load sensing and control function of a telescopic forklift. The hydraulic control valve designed in this invention, capable of achieving pressure stabilization and selection, is one of the key components for realizing the load sensing and control function of a telescopic forklift.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: Through the synergistic effect of the accumulator and the shuttle valve, dynamic pressure stability is achieved in the traditional load-sensitive system, which has the ability to resist shock and suppress oscillation, and is especially suitable for engineering machinery with frequent load fluctuations and equipment with high requirements for smooth operation. Attached Figure Description

[0014] Figure 1 Schematic diagram of the working system of the load feedback pressure regulating selector valve; Figure 2 This is a schematic diagram of the oil circuit for the load feedback pressure regulating selector valve during operation. Figure 3 This is a schematic diagram of the oil circuit for the load feedback pressure stabilizing selector valve during braking. Figure 4 This is a schematic diagram of the oil circuit for the load feedback pressure stabilizing selector valve during steering. Detailed Implementation

[0015] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0016] like Figures 1-2 As shown, the present invention discloses a load feedback pressure regulating selector valve, including a valve body 1. The valve body 1 is provided with a first oil inlet 7, a second oil inlet 8, and a third oil inlet 9 connected to an actuator. The first oil inlet 7 is connected to a main valve (controlling actions such as telescopic, luffing, etc.), the second oil inlet 8 is connected to a brake valve, and the third oil inlet 9 is connected to a steering gear. The first oil inlet 7, the second oil inlet 8, and the third oil inlet 9 are respectively connected to the LS1 oil circuit, the LS2 oil circuit, and the LS3 oil circuit. The LS1 oil circuit is connected to a dynamic pressure regulating accumulator 4. The valve body 1 is provided with a main oil circuit LS connected to a variable pump 2. The main oil circuit LS is connected to the LS1 oil circuit, the LS2 oil circuit, and the LS3 oil circuit. A shuttle valve 3 is provided at the intersection of the LS1 oil circuit, the LS2 oil circuit, and the LS3 oil circuit to transmit pressure signals. The highest pressure oil is delivered to the variable pump 2 through the shuttle valve 3.

[0017] When the working pressure changes suddenly, the accumulator 4 plays a role in pressure stabilization, and the dynamic pressure stabilization process of the accumulator 4 is as follows: when the load increases suddenly, the accumulator 4 is filled with liquid, part of the high-pressure oil is temporarily stored in the accumulator 4, the LS total oil way pressure rises smoothly, and the over-regulation of the one-way pump on the LS1 oil way, the LS2 oil way and the LS3 oil way is avoided. When the load decreases suddenly, the accumulator 4 discharges oil, the high-pressure oil is supplemented to the LS total oil way, the pressure drop speed is slowed down, and the stable pressure supply of the pump is maintained. The pre-charge pressure of the accumulator 4 needs to be lower than the minimum working load pressure of the system, so as to ensure that the accumulator 4 is activated only in abnormal fluctuations and avoid interfering with the normal LS total oil way signal. The volume of the accumulator 4 is calculated according to the maximum flow fluctuation of the system and the allowable pressure fluctuation range: when absorbing the pressure fluctuation of the hydraulic pump, the average fluctuation pressure is generally 60% of the charging pressure, and if it is too small, the vibration absorption capacity is insufficient, and if it is too large, the response is sluggish.

[0018] When multiple loads are considered at the same time, independent control of each action needs to be realized, and the pressure oil is kept stable through the shuttle valve 3. The shuttle valve 3 is a two-in-one-out hydraulic control switching valve, when the load increases or decreases suddenly, the shuttle valve core 5 is pushed to the A port or the B port with lower oil pressure, so that the A-T port or the B-T port is connected, and finally the pressure oil is discharged to the LS total oil way. By comparing the highest pressure between the oil ways, the highest pressure signal is selected and transmitted to the variable pump 2, the variable pump 2 adjusts the required output pressure, the shuttle valve 3 completes the selection and transmission of the pressure signal, and the dynamic stability of the pressure is realized.

[0019] The accumulator 4 and the shuttle valve 3 cooperate to realize the dynamic stability of the pressure in the traditional load sensing system, have the ability of anti-impact and oscillation suppression, and are especially suitable for engineering machinery with frequent load fluctuations and equipment with high requirements for action stability.

[0020] As shown in Figure 2 , when the vehicle is working, the main valve generates a load pressure, the LS1 oil way is filled with oil, the shuttle valve core 5 moves to the right, the LS1 oil way is connected with the variable pump 2, the variable pump 2 detects the pressure change of the LS1 oil way, and immediately adjusts the output pressure to the pressure required to meet the demand.

[0021] As shown in Figure 3 , when the vehicle is braking, the brake valve generates a load pressure, the LS2 oil way is filled with oil, the shuttle valve core at the intersection of the LS2 oil way and the LS3 oil way moves to the right, the shuttle valve core at the intersection of the LS1 oil way, the LS2 oil way and the LS3 oil way moves to the left, the LS2 oil way is connected with the LS main oil way, and the pressure oil is discharged through the oil outlet 6.

[0022] As shown in Figure 4 , when the vehicle is steering, the steering gear generates a load pressure, the LS3 oil way is filled with oil, the shuttle valve core 5 at the intersection of the oil ways moves to the left, the LS3 oil way is connected with the LS main oil way, and the pressure oil is discharged through the oil outlet 6.

Claims

1. A load feedback pressure-stabilizing selector valve comprising a valve body (1) provided with an oil inlet connected to an actuator and an oil outlet (6) connected to a variable pump (2), the oil outlet (6) being in fluid communication with the oil inlets, characterized in that, The oil inlet oil path intersection is provided with a shuttle valve (3) for controlling the highest pressure oil to be delivered to the variable pump (2), and the oil inlet oil path is connected to the accumulator (4) for charging or discharging.

2. The load feedback pressure regulating selector valve according to claim 1, wherein The shuttle valve (3) is a three-way structure.

3. The load feedback pressure regulating selector valve of claim 2, wherein, The three-way structure includes a valve core (5) for controlling the flow of pressure oil.

4. The load feedback pressure regulating selector valve of claim 1, wherein, The oil outlet (6) is connected to the main oil path.

5. The load feedback pressure regulating selector valve of claim 4, wherein, The main oil path is connected to the variable pump (2).

6. The load feedback pressure regulating selector valve of claim 1, wherein, The actuator is a main valve, a brake valve or a steering gear.

7. The load feedback pressure regulating selector valve of claim 1, wherein, The first oil inlet (7) is connected to the main valve.

8. The load feedback pressure regulating selector valve of claim 1, wherein, The second oil inlet (8) is connected to the brake valve.

9. The load feedback pressure regulating selector valve of claim 1, wherein, The third oil inlet (9) is connected to the steering gear.

10. The load feedback pressure regulating selector valve of claim 1, wherein, The accumulator (4) is fixed to the valve body (1).

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