A buffer valve group and a slewing system

Abstract

The utility model discloses a buffer valve group and rotary system, buffer valve group includes shuttle valve and hydraulic control reversing valve, and the oil inlet a mouth and b mouth of shuttle valve are connected with rotary handle, and the oil outlet of shuttle valve is connected hydraulic control reversing valve pressure oil port, and the working oil port A mouth and B mouth of hydraulic control reversing valve are connected between rotary motor inlet and outlet oil port A mouth and B mouth, and the oil return port of hydraulic control reversing valve is connected oil tank, and rotary system includes rotary pump, the rotary motor of rotary pump drive, and the buffer valve group of parallel connection in rotary motor inlet and outlet oil port, the buffer valve group for application in rotary system can effectively buffer release, and because of the rotary sudden acceleration of rotary pump flow sudden change or pressure impact brings etc.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, and in particular to a buffer valve assembly and a rotary system. Background Technology

[0002] The slewing system of crawler cranes typically uses a full-slewing hydraulic motor drive. A simplified schematic diagram of an existing hydraulically controlled closed-loop slewing system is shown below. Figure 1 As shown: A closed-loop rotary pump drives one or more parallel rotary motors. The characteristics of a closed-loop rotary system determine that the quality of the rotary operation directly depends on the performance of the rotary pump, especially its proportional control characteristics, low-flow stability, and symmetry. Due to the large rotational inertia, long boom, and high height of the crane, even a small fluctuation in the flow rate of the rotary pump will be amplified by the entire vehicle mechanism, causing varying degrees of vibration and impact. Therefore, a buffer valve assembly is needed to be integrated into the rotary system to reduce vibration and impact problems caused by flow fluctuations in the entire vehicle mechanism. Utility Model Content

[0003] Purpose of the utility model: The purpose of this utility model is to provide a buffer valve assembly and a rotary system that can effectively buffer and release problems such as sudden acceleration of rotary pump due to sudden changes in flow rate or pressure shock, resulting in poor micro-motion.

[0004] Technical solution: To achieve the above objectives, the present invention provides a buffer valve assembly, comprising a shuttle valve and a hydraulic directional valve. The inlet ports a and b of the shuttle valve are connected to the rotary handle, and the outlet port of the shuttle valve is connected to the pressure port of the hydraulic directional valve. The working ports A and B of the hydraulic directional valve are connected in parallel between the inlet and outlet ports A and B of the rotary motor, and the return port of the hydraulic directional valve is connected to the oil tank.

[0005] Preferably, the hydraulically controlled directional valve is a two-position valve.

[0006] The rotary system applicable to the buffer valve group described in this utility model includes a rotary pump, a rotary motor driven by the rotary pump, and a buffer valve group connected in parallel to the oil inlet and outlet of the rotary motor.

[0007] Preferably, the rotary pump is a closed-loop variable pump.

[0008] Preferably, the rotary pump drives one or more parallel rotary motors.

[0009] Beneficial effects: This utility model has the following advantages: 1. The buffer valve group applied to the rotary system described in this utility model can effectively buffer the release and prevent problems such as sudden acceleration of the rotary pump due to sudden changes in flow rate or pressure shock, which are caused by poor micro-motion; 2. The initial position of the rotary buffer valve ensures that before the pressure of the rotary system is established, there will be no unsafe rotary problems caused by the passive rotation of the rotary motor due to external load; 3. The throttling groove of the proportional variable of the buffer valve group makes the slow start and rush-off transition of the rotary smooth, while not affecting the maximum speed performance of the rotary system. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the principle of an existing hydraulically controlled closed-loop rotary system.

[0011] Figure 2 This is a schematic diagram of the buffer valve assembly.

[0012] Figures 3-5 The figures show the valve core displacement of the buffer valve assembly in the initial state, and at the 2.5mm reversal and final positions, respectively.

[0013] Figure 6 This is a schematic diagram of the rotary system based on the buffer valve assembly described in this utility model. Detailed Implementation

[0014] The technical solution of this utility model will be described in detail below with reference to the embodiments and accompanying drawings.

[0015] like Figure 2 and 6 As shown, the rotary system of this utility model includes a rotary pump 1, a rotary motor 2 driven by the rotary pump, and a buffer valve assembly 3 connected in parallel to the inlet and outlet ports of the rotary motor. The buffer valve assembly 3 includes a shuttle valve and a hydraulically controlled directional valve. The inlet ports a and b of the shuttle valve are connected to the rotary handle, and the outlet port of the shuttle valve is connected to the pressure port of the hydraulically controlled directional valve. The working ports A and B of the hydraulically controlled directional valve are connected in parallel between the inlet and outlet ports A and B of the rotary motor, and the return port of the hydraulically controlled directional valve is connected to the oil tank.

[0016] like Figures 3-5 The figures show the valve core displacement diagrams of the buffer valve assembly in the initial state, at 2.5mm reversal, and in the final position. With the rotary handle in the neutral position, there is no pilot pressure output, and neither of the shuttle valve's two inlets (port a and port b) receives pressurized oil, nor does the outlet output pressurized oil. The valve core of the hydraulic directional valve also remains in the initial neutral position. In this state, ports A and B of the hydraulic directional valve are closed, with the valve core dead zone (0.6mm) ensuring that ports A and B are not connected. Therefore, when the rotary handle is in the neutral position, external forces such as vehicle levelness or strong winds will not cause the motor to rotate, resulting in uncontrollable rotation.

[0017] Operating the rotary handle, such as to the right, inputs a gradually increasing rotary pilot pressure (e.g., from 0 bar to 5 bar) into port b of the shuttle valve. This drives the buffer valve spool to move, creating a variable throttle orifice. The pressure oil on sides A and B of the rotary motor 2 is connected through the throttle orifice, thereby reducing the drive flow, lowering pressure shock, and buffering the start-up rotary motion.

[0018] By operating the rotary handle, the rotary pilot variable pressure oil causes the rotary pump 1 to change direction, generating system flow. At the same time, the rotary pilot variable pressure is judged by a pressure sensor or pressure switch. When the rotary pilot pressure is >5 bar when the rotary handle is operated, the rotary operation is determined to be valid, the rotary control solenoid valve is energized, and the pilot pressure oil opens the rotary brake through the brake oil circuit. The rotary pressure oil drives the rotary motor 2 to rotate, generating the rotary action.

[0019] When the rotary handle is operated to achieve a pilot pressure > 5 bar, the pilot pressure entering port a or b of the shuttle valve will push the buffer valve core to displace. When the pilot pressure at port a or b of the shuttle valve reaches 5 bar, the throttling orifice of port A / B of the hydraulic directional valve is at its maximum, typically designed to have a flow area equivalent to a φ5 diameter throttling orifice. As the rotary operating handle is pushed further, the pilot pressure continuously increases, and the throttling grooves at ports A and B gradually decrease. When the handle is pushed to approximately half of the entire operating stroke, the throttling connection between ports A and B of the hydraulic directional valve closes.

[0020] The buffer valve assembly only functions during the start and stop strokes of the slewing operation. When the slewing handle is pushed to the maximum stroke, the slewing effect is shut off, without affecting the maximum slewing speed. The closed-loop slewing system with the buffer valve assembly can effectively solve the problems of large start-stop impact and poor micro-motion performance caused by differences in the performance of closed-loop slewing pumps.

Claims

1. A buffer valve assembly, characterized in that, It includes a shuttle valve and a hydraulic directional valve. The inlet ports a and b of the shuttle valve are connected to the rotary handle. The outlet port of the shuttle valve is connected to the pressure port of the hydraulic directional valve. The working ports A and B of the hydraulic directional valve are connected in parallel between the inlet and outlet ports A and B of the rotary motor. The return port of the hydraulic directional valve is connected to the oil tank.

2. The buffer valve assembly according to claim 1, characterized in that, The hydraulically controlled directional valve is a two-position valve.

3. A rotary system suitable for the buffer valve assembly of claim 1, characterized in that, It includes a rotary pump (1), a rotary motor (2) driven by the rotary pump (1), and a buffer valve group (3) connected in parallel to the oil inlet and outlet of the rotary motor (2).

4. The rotary system according to claim 3, characterized in that, The rotary pump (1) is a closed-loop variable pump.

5. The rotary system according to claim 3, characterized in that, The rotary pump (1) drives one or more parallel rotary motors.

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