Anti-Impact Rotary Control System and Its Control Method

Abstract

The present invention discloses an anti-shock slewing control system and its control method, which includes a slewing mechanism, a working joint valve rod, a first hydraulic proportional overflow valve, and a second hydraulic proportional overflow valve. The working oil ports C1 and C2 are connected to the oil inlet P, the working oil port C3 is connected to the oil return port T, the working oil port C4 is connected to the oil inlet D1 and the working oil port A, the working oil port C5 is connected to the oil return ports D2, E2, and T, the working oil port C6 is connected to the oil inlet E1 and the working oil port B, the control oil port C7 is connected to the pilot oil port a of the pilot oil source, the control oil port C8 is connected to the pilot oil port b of the pilot oil source, the control oil port D3 is connected to the pilot oil port a of the pilot oil source, and the control oil port E3 is connected to the pilot oil port b of the pilot oil source. The purpose of the present invention is to solve problems such as poor anti-shock effect, large impact during start and stop, and small speed reduction during the valve rod reset process due to too low back pressure of the valve rod.

Description

Technical Field

[0001] The present invention relates to a slewing control system on a crane, and particularly to an anti-shock slewing control system and a control method thereof. Background Art

[0002] At present, the slewing systems in the upper hydraulic systems of truck cranes are mainly divided into closed-loop pump control systems and open systems. Among them, the open slewing system consists of a gear pump, a slewing buffer valve, a slewing mechanism, etc. It is widely used in medium and small tonnage cranes (usually products with a tonnage of 80 tons and below), with good effects and low costs. However, its disadvantages are poor overall anti-shock effect, large impact at start and stop moments, and the problem of small speed reduction during the valve stem reset process due to too low back pressure of the valve stem.

[0003] In the prior art, the technical solution adopted to solve the above problems is a constant-value anti-shock device. That is, during the slewing process of the crane, the load fluctuates greatly. Adding an anti-shock device to the slewing system can improve the anti-load fluctuation interference ability of the slewing system. At present, all anti-shock devices are set to constant values. In order to meet the requirements of heavy-duty operation conditions, the set values of the anti-shock devices are generally on the high side, and the overall anti-shock effect is poor. Among them, the hydraulic oil output by the gear pump enters the slewing mechanism through the slewing directional valve, and the high-pressure hydraulic oil drives the motor to rotate to drive the slewing mechanism to work. When the instantaneous pressure in the slewing system is too high and reaches the set value of the anti-shock device, the inlet and outlet ports of the motor are connected, achieving an anti-shock effect. However, the constant-value anti-shock device in the prior art has the following disadvantages:

[0004] (1) The anti-shock device is a constant value. To meet the requirements of heavy-duty working conditions, the set value is on the high side, and the ability to filter pressure shock at start and stop moments is poor, resulting in large pressure shocks at start and stop moments and obvious shaking.

[0005] (2) The main oil circuit can only return oil through the working connection valve stem, and the valve stem needs to meet both the idle speed and rated speed states at the same time, and it cannot solve the problem of small speed reduction during the idle valve stem reset process due to too low back pressure value of the valve stem.

[0006] There is also a variable-value anti-shock device in the prior art, that is, the set value of the anti-shock device is not constant and can change dynamically according to the working state to meet the requirements of different states and improve the overall anti-shock effect. For example, an electro-hydraulic proportional relief valve is used, but realizing the change of the relief valve pressure set value through current change has high costs, complex control, and is not conducive to popularization.

[0007] Therefore, it is urgent to solve the above problems. Summary of the Invention

[0008] Object of the Invention: The first object of the present invention is to provide an anti-shock slewing control system, aiming to solve problems such as poor anti-shock effect, large impact at start and stop moments, and small speed reduction during the valve stem reset process due to too low back pressure of the valve stem.

[0009] The second object of the present invention is to provide a control method for the impact-proof slewing control system.

[0010] Technical solution: To achieve the above object, the present invention discloses an impact-proof slewing control system, including a slewing mechanism having a working oil port A and a working oil port B, a working joint valve rod, a first hydraulic proportional relief valve, and a second hydraulic proportional relief valve.

[0011] The working oil ports C1 and C2 of the working joint valve rod are communicated with the oil inlet port P, the working oil port C3 of the working joint valve rod is communicated with the oil return port T, the working oil port C4 of the working joint valve rod is communicated with the oil inlet port D1 of the first hydraulic proportional relief valve and the working oil port A of the slewing mechanism, the working oil port C5 of the working joint valve rod is communicated with the oil return port D2 of the first hydraulic proportional relief valve, the oil return port E2 of the second hydraulic proportional relief valve, and the oil return port T, the working oil port C6 of the working joint valve rod is communicated with the oil inlet port E1 of the second hydraulic proportional relief valve and the working oil port B of the slewing mechanism, the control oil port C7 of the working joint valve rod is communicated with the pilot oil port a of the pilot oil source, the control oil port C8 of the working joint valve rod is communicated with the pilot oil port b of the pilot oil source, the control oil port D3 of the first hydraulic proportional relief valve is communicated with the pilot oil port a of the pilot oil source, and the control oil port E3 of the second hydraulic proportional relief valve is communicated with the pilot oil port b of the pilot oil source.

[0012] Wherein, a first throttle valve and a first filter screen are sequentially arranged between the control oil port C7 of the working joint valve rod and the pilot oil port a of the pilot oil source, and a second throttle valve and a second filter screen are sequentially arranged between the control oil port C8 of the working joint valve rod and the pilot oil port b of the pilot oil source.

[0013] Preferably, it further includes a first check valve and a second check valve. The oil inlet ports of the first check valve and the second check valve are both communicated with the working oil port C5 of the working joint valve rod, the oil return port D2 of the first hydraulic proportional relief valve, and the oil return port E2 of the second hydraulic proportional relief valve. The oil outlet port of the first check valve is communicated with the working oil port C4 of the working joint valve rod, and the oil port of the second check valve is communicated with the working oil port C6 of the working joint valve rod.

[0014] Furthermore, the working joint valve rod is a three-position six-way directional control valve. When pilot oil is input into the pilot oil port a, the working joint valve rod moves leftward, the working oil ports C1 and C4 of the working joint valve rod are communicated, and the working oil ports C6 and C3 of the working joint valve rod are communicated.

[0015] When pilot oil is input into the pilot oil port b, the working joint valve rod moves rightward, the working oil ports C1 and C6 of the working joint valve rod are communicated, and the working oil ports C4 and C3 of the working joint valve rod are communicated.

[0016] When the working joint valve rod is in the middle position, the working oil ports C2 and C5 of the working joint valve rod are communicated.

[0017] A control method for an impact-proof slewing control system of the present invention includes the following steps:

[0018] When pilot oil is input into the pilot oil port a, the set pressure of the first hydraulic proportional overflow valve changes in direct proportion to the pilot control pressure of the pilot oil port a. When the pilot control pressure of the pilot oil port a reaches the maximum, the set value P2 of the first hydraulic proportional overflow valve is the largest; since no pilot oil is input into the pilot oil port b, the set value of the second hydraulic proportional overflow valve is P1;

[0019] In the starting stage, since the set value of the first hydraulic proportional overflow valve increases in direct proportion to the increase of the pilot pressure, when the starting moment pressure shock > the transient pressure of the first hydraulic proportional overflow valve, the first hydraulic proportional overflow valve plays a filtering role to reduce the starting state pressure shock;

[0020] In the transient stop stage when the slewing control handle returns to the middle position, the transient pressures of both the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve are the set value P1, and both directions can play a filtering role to reduce the pressure shock in the transient stop stage.

[0021] A control method for an impact-proof slewing control system of the present invention includes the following steps:

[0022] When pilot oil is input into the pilot oil port b, the set pressure of the second hydraulic proportional overflow valve changes in direct proportion to the pilot control pressure of the pilot oil port b. When the pilot control pressure of the pilot oil port b reaches the maximum, the set value P2 of the second hydraulic overflow valve is the largest; since no pilot oil is input into the pilot oil port a, the set value of the first hydraulic overflow valve is P1;

[0023] In the starting stage, since the set value of the second hydraulic proportional overflow valve increases in direct proportion to the increase of the pilot pressure, when the starting moment pressure shock > the transient pressure of the second hydraulic proportional overflow valve, the second hydraulic proportional overflow valve plays a filtering role to reduce the starting state pressure shock;

[0024] In the transient stop stage when the slewing control handle returns to the middle position, the transient pressures of both the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve are the set value P1, and both directions can play a filtering role to reduce the pressure shock in the transient stop stage.

[0025] A control method for an impact-proof slewing control system of the present invention includes the following steps:

[0026] When the working state is idle speed, the oil return back pressure of the working joint valve rod < the set values P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When the working joint valve rod is in the middle position, the working oil ports C2 and C5 of the working joint valve rod are connected, and the oil fluid enters from the oil inlet P, passes through the working oil ports C2 and C5 of the working joint valve rod, and returns to the oil return port T. The main oil circuit directly returns oil through the working joint valve rod.

[0027] A control method for an anti - impact slewing control system of the present invention includes the following steps: When the working state is at the rated speed, the back pressure of the return oil of the working joint valve rod > the set values P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When pilot oil is input at the pilot oil port a, the working joint valve rod moves leftward, the working oil ports C1 and C4 of the working joint valve rod are connected, and the working oil ports C6 and C3 of the working joint valve rod are connected; One way of the return oil of the slewing mechanism working oil port B returns to the return oil port T through the second hydraulic proportional overflow valve, and the other way of the return oil of the slewing mechanism working oil port B returns to the return oil port T through the working oil ports C6 and C3 of the working joint valve rod, and the main oil circuit returns oil bidirectionally through the working joint valve rod and the second proportional overflow valve.

[0028] A control method for an anti - impact slewing control system of the present invention includes the following steps: When the working state is at the rated speed, the back pressure of the return oil of the working joint valve rod > the set values P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When pilot oil is input at the pilot oil port b, the working joint valve rod moves rightward, the working oil ports C1 and C6 of the working joint valve rod are connected, and the working oil ports C4 and C3 of the working joint valve rod are connected; One way of the return oil of the slewing mechanism working oil port A returns to the return oil port T through the first hydraulic proportional overflow valve, and the other way of the return oil of the slewing mechanism working oil port A returns to the return oil port T through the working oil ports C4 and C3 of the working joint valve rod, and the main oil circuit returns oil bidirectionally through the working joint valve rod and the first proportional overflow valve.

[0029] A control method for an anti - impact slewing control system of the present invention includes the following steps:

[0030] In the non - working state, when there is no pilot oil in the pilot control oil circuit, that is, neither at the pilot oil port a nor at the pilot oil port b, the set values of both the first hydraulic overflow valve and the second hydraulic overflow valve are the set value P1.

[0031] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0032] (1) The present invention uses a hydraulic proportional overflow valve to prevent impact, and its anti - impact set value can change dynamically according to the working state, which can effectively reduce the pressure impact at the start - stop moment, improve its overall anti - impact effect, and solve the problems of poor anti - impact effect, large impact at the start - stop moment, and small speed reduction during the valve rod reset process due to too low back pressure of the valve rod.

[0033] (2) The present invention realizes the return oil of the working joint valve rod at idling speed and the bidirectional return oil of the working joint valve rod + hydraulic proportional overflow valve at high speed, which can further increase the back pressure of the return oil of the working joint valve rod at idling speed, and further improve the throttling and deceleration effect of the working joint valve rod at idling speed, and finally achieve the goal of maximizing the attenuation of inertia during the reset process of the working joint valve rod.

[0034] (3) The boost oil source of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve of the present invention is taken from the feedback oil circuit. The spring chamber (control oil port) of the hydraulic proportional overflow valve is connected to the pilot oil port of the working joint valve rod, and the set value of the overflow valve pressure is changed through the change of the pilot pressure. The cost is low and no control is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is the hydraulic schematic diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] It should be understood that the present invention can be implemented in different forms and should not be construed as limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of the components may be exaggerated. The same reference numerals throughout the drawings denote the same components.

[0038] As Figure 1 shown, an anti-shock slewing control system of the present invention includes a slewing mechanism 1, a working joint valve rod 2, a first hydraulic proportional overflow valve 3, a second hydraulic proportional overflow valve 4, a first throttle valve 5, a first filter screen 6, a second throttle valve 7, a second filter screen 8, a first check valve 9 and a second check valve 10.

[0039] The slewing mechanism 1 has a working oil port A and a working oil port B. The working connection valve rod 2 is a three-position six-way directional control valve. The working connection valve rod 2 has a working oil port C1, a working oil port C2, a working oil port C3, a working oil port C4, a working oil port C5, and a working oil port C6. The illustration of the working connection valve rod 2 only represents the function of commutation, not limited to a three-position six-way directional control valve, and the specific internal structure is not elaborated in detail. The slewing mechanism 1 is not limited to a slewing motor. The working oil ports C1 and C2 of the working connection valve rod 2 are connected to the oil inlet port P. The working oil port C3 of the working connection valve rod 2 is connected to the oil return port T. The working oil port C4 of the working connection valve rod 2 is connected to the oil inlet port D1 of the first hydraulic proportional relief valve 3 and the working oil port A of the slewing mechanism 1. The working oil port C5 of the working connection valve rod 2 is connected to the oil return port D2 of the first hydraulic proportional relief valve 3, the oil return port E2 of the second hydraulic proportional relief valve 4, and the oil return port T. The working oil port C6 of the working connection valve rod 2 is connected to the oil inlet port E1 of the second hydraulic proportional relief valve 4 and the working oil port B of the slewing mechanism 1. The control oil port C7 of the working connection valve rod 2 is connected to the pilot oil port a of the pilot oil source. A first throttle valve 5 and a first filter screen 6 are sequentially arranged between the control oil port C7 of the working connection valve rod and the pilot oil port a of the pilot oil source. The control oil port C8 of the working connection valve rod 2 is connected to the pilot oil port b of the pilot oil source. A second throttle valve 7 and a second filter screen 8 are sequentially arranged between the control oil port C8 of the working connection valve rod and the pilot oil port b of the pilot oil source. The control oil port D3 of the first hydraulic proportional relief valve 3 is connected to the pilot oil port a of the pilot oil source. The control oil port E3 of the second hydraulic proportional relief valve 4 is connected to the pilot oil port b of the pilot oil source. The oil inlet ports of the first check valve and the second check valve are both connected to the working oil port C5 of the working connection valve rod, the oil return port D2 of the first hydraulic proportional relief valve, and the oil return port E2 of the second hydraulic proportional relief valve. The oil outlet port of the first check valve is connected to the working oil port C4 of the working connection valve rod. The oil port of the second check valve is connected to the working oil port C6 of the working connection valve rod.

[0040] When pilot oil is input into the pilot oil port a, the working connection valve rod moves leftward, the working oil ports C1 and C4 of the working connection valve rod are connected, and the working oil ports C6 and C3 of the working connection valve rod are connected;

[0041] When pilot oil is input into the pilot oil port b, the working connection valve rod moves rightward, the working oil ports C1 and C6 of the working connection valve rod are connected, and the working oil ports C4 and C3 of the working connection valve rod are connected;

[0042] When the working connection valve rod is in the middle position, the working oil ports C2 and C5 of the working connection valve rod are connected.

[0043] The boost oil source of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve of the present invention is taken from the feedback oil circuit. The spring chamber (control oil port) of the hydraulic proportional overflow valve is connected to the pilot oil port of the working joint valve rod, and the set value of the overflow valve is changed through the change of the pilot pressure, with low cost and no need for control participation.

[0044] A control method for an anti-shock slewing control system of the present invention includes the following steps:

[0045] In the non-working state, that is, the standby state, when there is no pilot oil in the pilot control oil circuit, that is, either pilot oil port a or pilot oil port b, the set values of the first hydraulic overflow valve and the second hydraulic overflow valve are both the set value P1;

[0046] The working state is divided into two states: idle speed and rated speed. In both states, the anti-shock principle is the same, and the difference is mainly reflected in the main oil circuit oil return principle;

[0047] When there is pilot oil input to pilot oil port a, the set pressure of the first hydraulic proportional overflow valve changes in direct proportion to the pilot control pressure of pilot oil port a. When the pilot control pressure of pilot oil port a reaches the maximum, the set value P2 of the first hydraulic proportional overflow valve is the largest; since there is no pilot oil input to pilot oil port b, the set value of the second hydraulic proportional overflow valve is P1;

[0048] In the starting stage, since the set value of the first hydraulic proportional overflow valve increases in direct proportion to the increase of the pilot pressure, when the starting moment pressure shock > the transient pressure of the first hydraulic proportional overflow valve, the first hydraulic proportional overflow valve plays a filtering role to reduce the pressure shock in the starting state;

[0049] In the transient stop stage when the slewing control handle returns to the middle position, the transient pressures of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve are both the set value P1, and both directions can play a filtering role to reduce the pressure shock in the transient stop stage;

[0050] When there is pilot oil input to pilot oil port b, the set pressure of the second hydraulic proportional overflow valve changes in direct proportion to the pilot control pressure of pilot oil port b. When the pilot control pressure of pilot oil port b reaches the maximum, the set value P2 of the second hydraulic overflow valve is the largest; since there is no pilot oil input to pilot oil port a, the set value of the first hydraulic overflow valve is P1;

[0051] In the starting stage, since the set value of the second hydraulic proportional overflow valve increases in direct proportion to the increase of the pilot pressure, when the starting moment pressure shock > the transient pressure of the second hydraulic proportional overflow valve, the second hydraulic proportional overflow valve plays a filtering role to reduce the pressure shock in the starting state;

[0052] During the transient stop stage when the rotary control handle returns to the neutral position, the transient pressures of both the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve are the set value P1, which can filter in both directions and reduce the pressure shock during the transient stop stage;

[0053] When the working state is idling, the oil return back pressure of the working joint valve rod < the set value P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When the working joint valve rod is in the neutral position, the working oil ports C2 and C5 of the working joint valve rod are connected, and the oil flows from the oil inlet P into the working oil ports C2 and C5 of the working joint valve rod and returns to the oil return port T. The main oil circuit directly returns oil through the working joint valve rod.

[0054] When the working state is at the rated speed, the oil return back pressure of the working joint valve rod > the set value P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When there is pilot oil input at the pilot oil port a, the working joint valve rod moves leftward, and the working oil ports C1 and C4 of the working joint valve rod are connected, and the working oil ports C6 and C3 of the working joint valve rod are connected; One way of the oil return from the oil return port B of the slewing mechanism returns to the oil return port T through the second hydraulic proportional overflow valve, and the other way of the oil return from the oil return port B of the slewing mechanism returns to the oil return port T through the working oil ports C6 and C3 of the working joint valve rod. The main oil circuit returns oil bidirectionally through the working joint valve rod and the second proportional overflow valve;

[0055] When the working state is at the rated speed, the oil return back pressure of the working joint valve rod > the set value P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When there is pilot oil input at the pilot oil port b, the working joint valve rod moves rightward, and the working oil ports C1 and C6 of the working joint valve rod are connected, and the working oil ports C4 and C3 of the working joint valve rod are connected; One way of the oil return from the oil return port A of the slewing mechanism returns to the oil return port T through the first hydraulic proportional overflow valve, and the other way of the oil return from the oil return port A of the slewing mechanism returns to the oil return port T through the working oil ports C4 and C3 of the working joint valve rod. The main oil circuit returns oil bidirectionally through the working joint valve rod and the first proportional overflow valve;

[0056] Through bidirectional oil return, the present invention can further increase the back pressure of the working joint valve rod and solve the problem of small speed reduction during the valve rod reset process due to too low valve rod back pressure.

Claims

1. A control method for an impact-resistant slewing control system, characterized in that, The anti-shock slewing control system includes a slewing mechanism (1) with a working oil port A and a working oil port B, a working connection valve rod (2), a first hydraulic proportional overflow valve (3), and a second hydraulic proportional overflow valve (4). The working oil ports C1 and C2 of the working connection valve rod (2) are connected to the oil inlet port P. The working oil port C3 of the working connection valve rod (2) is connected to the oil return port T. The working oil port C4 of the working connection valve rod (2) is connected to the oil inlet port D1 of the first hydraulic proportional overflow valve (3) and the working oil port A of the slewing mechanism (1). The working oil port C5 of the working connection valve rod (2) is connected to the oil return port D2 of the first hydraulic proportional overflow valve (3), the oil return port E2 of the second hydraulic proportional overflow valve (4), and the oil return port T. The working oil port C6 of the working connection valve rod (2) is connected to the oil inlet port E1 of the second hydraulic proportional overflow valve (4) and the working oil port B of the slewing mechanism (1). The control oil port C7 of the working connection valve rod (2) is connected to the pilot oil port a of the pilot oil source. The control oil port C8 of the working connection valve rod (2) is connected to the pilot oil port b of the pilot oil source. The control oil port D3 of the first hydraulic proportional overflow valve (3) is connected to the pilot oil port a of the pilot oil source. The control oil port E3 of the second hydraulic proportional overflow valve (4) is connected to the pilot oil port b of the pilot oil source. It includes the following steps: When pilot oil is input into the pilot oil port a, the set pressure of the first hydraulic proportional overflow valve changes in direct proportion to the pilot control pressure of the pilot oil port a. When the pilot control pressure of the pilot oil port a reaches the maximum, the set value P2 of the first hydraulic proportional overflow valve is the largest. Since no pilot oil is input into the pilot oil port b, the set value of the second hydraulic proportional overflow valve is P1. In the starting stage, since the set value of the first hydraulic proportional overflow valve increases in direct proportion to the increase of the pilot pressure, when the starting moment pressure shock > the transient pressure of the first hydraulic proportional overflow valve, the first hydraulic proportional overflow valve plays a filtering role to reduce the starting state pressure shock. In the transient stop stage when the slewing control handle returns to the middle position, the transient pressures of both the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve are the set value P1, and both directions can play a filtering role to reduce the pressure shock in the transient stop stage. When in the working state at the rated speed, the oil return back pressure of the working connection valve rod > the set values P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When pilot oil is input into the pilot oil port a, the working connection valve rod moves to the left, and the working oil ports C1 and C4 of the working connection valve rod are connected. The working oil ports C6 and C3 of the working connection valve rod are connected. The oil return of the working oil port B of the slewing mechanism returns to the oil return port T through the second hydraulic proportional overflow valve in one way, and in the other way, the oil return of the working oil port B of the slewing mechanism returns to the oil return port T through the working oil ports C6 and C3 of the working connection valve rod. The main oil circuit returns oil bidirectionally through the working connection valve rod and the second proportional overflow valve.

2. The control method of an impact-resistant slewing control system according to claim 1, characterized in that, It includes the following steps: When pilot oil is input into the pilot oil port b, the set pressure of the second hydraulic proportional overflow valve changes in direct proportion to the pilot control pressure of the pilot oil port b. When the pilot control pressure of the pilot oil port b reaches the maximum, the set value P2 of the second hydraulic overflow valve is the largest; since no pilot oil is input into the pilot oil port a, the set value of the first hydraulic overflow valve is P1. During the startup phase, since the set value of the second hydraulic proportional overflow valve increases in direct proportion to the increase in the pilot pressure, when the pressure shock at startup instant > the transient pressure of the second hydraulic proportional overflow valve, the second hydraulic proportional overflow valve plays a filtering role to reduce the pressure shock in the startup state. During the transient stop phase when the slewing control handle returns to the middle position, the transient pressures of both the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve are the set value P1, and both directions can play a filtering role to reduce the pressure shock during the transient stop phase.

3. The control method of an impact-resistant slewing control system according to claim 1, characterized in that, It includes the following steps: When the working state is idling, the oil return back pressure of the working joint valve rod < the set values P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When the working joint valve rod is in the middle position, the working oil ports C2 and C5 of the working joint valve rod are connected, and the oil flows from the oil inlet P into the working oil ports C2 and C5 of the working joint valve rod and returns to the oil return port T, and the main oil circuit directly returns oil through the working joint valve rod.

4. The control method of an impact-resistant slewing control system according to claim 1, characterized in that, It includes the following steps: When the working state is at the rated speed, the oil return back pressure of the working joint valve rod > the set values P1 of the first hydraulic proportional overflow valve and the second hydraulic proportional overflow valve. When pilot oil is input into the pilot oil port b, the working joint valve rod moves to the right, and the working oil ports C1 and C6 of the working joint valve rod are connected, and the working oil ports C4 and C3 of the working joint valve rod are connected; one way of the oil return from the working oil port A of the slewing mechanism returns to the oil return port T through the first hydraulic proportional overflow valve, and the other way of the oil return from the working oil port A of the slewing mechanism returns to the oil return port T through the working oil ports C4 and C3 of the working joint valve rod, and the main oil circuit returns oil bidirectionally through the working joint valve rod and the first proportional overflow valve.

5. The control method of an impact-proof rotary control system according to claim 1, characterized in that, It includes the following steps: In the non - working state, when there is no pilot oil in the pilot control oil circuit, that is, neither in the pilot oil port a nor in the pilot oil port b, the set values of both the first hydraulic overflow valve and the second hydraulic overflow valve are the set value P1.

6. The control method of an impact-resistant slewing control system according to claim 1, characterized in that, A first throttle valve (5) and a first filter screen (6) are sequentially arranged between the control oil port C7 of the working joint valve rod and the pilot oil port a of the pilot oil source, and a second throttle valve (7) and a second filter screen (8) are sequentially arranged between the control oil port C8 of the working joint valve rod and the pilot oil port b of the pilot oil source.

7. The control method of an impact-proof rotary control system according to claim 1, characterized in that, It also includes a first check valve (9) and a second check valve (10). The oil inlet of the first check valve and the oil inlet of the second check valve are both connected to the working oil port C5 of the working joint valve rod, the oil return port D2 of the first hydraulic proportional overflow valve, and the oil return port E2 of the second hydraulic proportional overflow valve. The oil outlet of the first check valve is connected to the working oil port C4 of the working joint valve rod, and the oil port of the second check valve is connected to the working oil port C6 of the working joint valve rod.

8. The control method of an impact-proof rotary control system according to claim 1, characterized in that The working joint valve rod (2) is a three - position six - way directional control valve. When pilot oil is input into the pilot oil port a, the working joint valve rod moves to the left, and the working oil ports C1 and C4 of the working joint valve rod are connected, and the working oil ports C6 and C3 of the working joint valve rod are connected. When pilot oil is input into the pilot oil port b, the working union valve rod moves to the right, the working oil ports C1 and C6 of the working union valve rod are connected, and the working oil ports C4 and C3 of the working union valve rod are connected; When the working union valve rod is in the middle position, the working oil ports C2 and C5 of the working union valve rod are connected.

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