Variable-amplitude oil cylinder control system and hoisting equipment

Abstract

A variable-amplitude oil cylinder control system comprises an operating valve, a variable-amplitude balance valve and a variable-amplitude oil cylinder, a first working oil port and a second working oil port of the operating valve are connected to a first oil port A1 and a second oil port B1 of the variable-amplitude balance valve respectively, and a third oil port A2 and a fourth oil port B2 of the variable-amplitude balance valve are connected to a rodless cavity and a rod cavity of the variable-amplitude oil cylinder respectively; the variable-amplitude balance valve comprises a pressure reducing valve, a first overflow valve, a throttling valve and a second overflow valve; the pressure reducing valve is arranged on an oil path between the first oil port A1 and the third oil port A2; an oil inlet of the pressure reducing valve is communicated to the third oil port A2, an oil outlet of the pressure reducing valve is communicated to the first oil port A1, and a control oil port of the pressure reducing valve is communicated to an oil way between the second oil port B1 and the fourth oil port B2; an oil inlet of the first overflow valve is communicated to an oil path between an oil inlet of the pressure reducing valve and the third oil port A2; the throttle valve is arranged on an oil path at one end of a control oil port of the pressure reducing valve; and the second overflow valve is arranged on an oil path between the second oil port B1 and the fourth oil port B2. The invention further relates to hoisting equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of luffing equipment, and in particular to a luffing oil cylinder control system and lifting equipment. Background Art

[0002] During the descent process, lifting equipment often encounters violent vibration of the cylinder, commonly known as amplitude vibration.

[0003] Figure 1 This is a schematic diagram of an existing lifting equipment luffing cylinder control system. Figure 1 As shown, the luffing cylinder control system includes a manual operating valve 1, a luffing balancing valve 2 and a luffing cylinder 3. The luffing balancing valve 2 includes a pressure reducing valve 21 and a relief valve 22. The luffing cylinder 3 raises / lowers the arm by changing the oil inlet and outlet direction of the rod chamber / rodless chamber of the luffing cylinder 3 through the manual operating valve 1, thereby achieving the lifting angle of the boom (the main arm of the lifting equipment).

[0004] When the boom is raised, oil flows into the rodless chamber 31 of the luffing cylinder 3, and the hydraulic oil enters the valve through the A1 port of the luffing balancing valve 2, and then comes out from the A2 port to enter the rodless chamber 31 of the luffing cylinder 3, pushing the cylinder piston to lift the boom. At this time, the hydraulic oil in the rod chamber 32 of the luffing cylinder 3 comes out, enters the valve through the B2 port of the luffing balancing valve 2, and comes out from the B1 port, and then returns to the oil tank 4 through the manual control valve 1. When the boom is lowered, oil flows into the rod chamber 32 of the luffing cylinder 3, and the hydraulic oil enters the valve through the B1 port of the luffing balancing valve 2, and then comes out from the B2 port to enter the rod chamber 32 of the luffing cylinder 3, pushing the cylinder piston to lower the boom. At this time, the hydraulic oil in the rodless chamber 31 of the luffing cylinder 3 comes out, enters the valve through the A2 port of the luffing balancing valve 2, and then comes out from the A1 port and returns to the oil tank 4 through the manual control valve 1. At this time, the overflow valve 22 in the luffing balancing valve 2 works, and the return oil creates back pressure, so that the boom falls smoothly.

[0005] When the boom needs to be stabilized at a certain position, the manual control valve 1 is in the middle position. Since the load on the luffing balancing valve 2 is large, the hydraulic oil returns through the manual control valve 1 into the oil tank 4. The luffing balancing valve 2 locks the oil circuit of the luffing cylinder 3, keeping the luffing cylinder 3 stationary.

[0006] During the retraction process of the luffing cylinder 3 (that is, during boom lowering), hydraulic oil flows from port B1 to port B2. It also flows through throttle valve 23 to the control port of pressure reducing valve 21, opening pressure reducing valve 21. This connects the oil circuit between ports A2 and A1, and the hydraulic oil returns to the tank through manual control valve 1, forming a closed loop. In the luffing balancing valve 2, relief valve 22 serves as a safety feature, preventing excessive system pressure during boom lowering. When system pressure exceeds the set pressure of relief valve 22, the hydraulic oil opens the valve core of relief valve 22, and excess hydraulic oil returns to tank 4 for pressure relief.

[0007] During the lowering process of the boom, due to the change in angle and the influence of friction, the pressure of the boom cylinder control system will continue to change, resulting in the opening of the pressure reducing valve 21 also changing continuously, causing instability in the system flow, thereby causing jitter when the boom is lowered, affecting the stability of the lifting operation of the lifting equipment, and having an adverse effect on some lifting operations with higher requirements. Summary of the Invention

[0008] In view of this, the luffing cylinder control system and lifting equipment provided by the present invention can effectively solve the problem of severe vibration of the cylinder during the luffing and lowering process of the lifting equipment, thereby avoiding luffing vibration.

[0009] An embodiment of the present invention provides a variable amplitude cylinder control system, comprising a control valve, a variable amplitude balancing valve and a variable amplitude cylinder, wherein the oil inlet P and the oil return port T of the control valve are both connected to the oil tank, the first working oil port and the second working oil port of the control valve are respectively connected to the first oil port A1 and the second oil port B1 of the variable amplitude balancing valve, the third oil port A2 and the fourth oil port B2 of the variable amplitude balancing valve are respectively connected to the rodless chamber and the rod chamber of the variable amplitude cylinder; the variable amplitude balancing valve comprises a pressure reducing valve, a first overflow valve, a throttle valve and a second overflow valve; the pressure reducing valve is arranged on the oil circuit between the first oil port A1 and the third oil port A2; the oil inlet of the pressure reducing valve is connected to the third oil port A2, and the oil outlet of the pressure reducing valve is connected to The first oil port A1 and the control oil port of the pressure reducing valve are connected to the oil circuit between the second oil port B1 and the fourth oil port B2; the oil inlet of the first overflow valve is connected to the oil circuit between the oil inlet of the pressure reducing valve and the third oil port A2, and the oil outlet of the first overflow valve is connected to the oil return port T1 of the variable amplitude balancing valve; the throttle valve is arranged on the oil circuit at one end of the control oil port of the pressure reducing valve; the second overflow valve is arranged on the oil circuit between the second oil port B1 and the fourth oil port B2, the oil inlet of the second overflow valve is connected to the second oil port B1, and the oil outlet of the second overflow valve is connected to the fourth oil port B2; and the oil return port T1 of the variable amplitude balancing valve is connected back to the oil tank.

[0010] Furthermore, the variable amplitude balancing valve further includes a one-way valve, which is arranged on the oil path between the oil outlet of the second relief valve and the oil return port T1 of the variable amplitude balancing valve.

[0011] Furthermore, the second overflow valve and the one-way valve are both of plug-in type.

[0012] Furthermore, the diameter of the damping hole of the throttle valve is 0.5 mm.

[0013] Furthermore, the control valve includes a reversing valve, which is a three-position six-way valve. Two of the oil inlets of the reversing valve are connected to the oil inlet P of the control valve, the oil return port of the reversing valve is connected to the oil return port T of the control valve, two of the three working oil ports of the reversing valve are respectively connected to the first working oil port and the second working oil port of the control valve, and another one of the three working oil ports of the reversing valve is connected to the oil return port T of the control valve.

[0014] Furthermore, the control valve further includes a third relief valve, which is connected to the oil circuit between the oil inlet P of the control valve and the oil return port T of the control valve.

[0015] Furthermore, the reversing valve has a control handle.

[0016] Furthermore, the luffing cylinder control system further includes an oil pump, which is connected to the oil circuit between the oil inlet P of the control valve and the oil tank.

[0017] An embodiment of the present invention further provides a lifting device, comprising the above-mentioned luffing cylinder control system.

[0018] In summary, the luffing cylinder control system and lifting equipment of the present invention have the following beneficial effects: 1. Prevents the problem of conventional variable-luffing balancing valves causing sudden jittering of lifting equipment due to load changes during the descent process; 2. A buffer device with sufficient stability for the pilot control pressure signal is designed for the pilot control oil circuit of the balancing valve; 3. The added second relief valve and one-way valve are both plug-in type, which has little impact on the entire variable amplitude balancing valve oil circuit. In addition, the external dimensions of the variable amplitude balancing valve remain basically unchanged compared with the existing technology, and can be directly interchanged with little cost change.

[0019] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic diagram of a luffing cylinder control system of an existing lifting equipment.

[0021] Figure 2 The figure is a schematic diagram of a luffing cylinder control system for lifting equipment according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the present invention is described in detail below with reference to the accompanying drawings and preferred embodiments.

[0023] Figure 2 This is a schematic diagram of a variable-luffing oil cylinder control system for lifting equipment according to a preferred embodiment of the present invention. Figure 2 The luffing cylinder control system of the present invention includes a control valve 50 , a luffing balancing valve 60 and a luffing cylinder 70 .

[0024] Specifically, the control valve 50 has an oil inlet P, an oil return port T, a first working oil port and a second working oil port. The oil inlet P and the oil return port T are both connected to the oil tank 80. The first working oil port and the second working oil port are respectively connected to the first oil port A1 and the second oil port B1 of the variable amplitude balancing valve 60. The third oil port A2 and the fourth oil port B2 of the variable amplitude balancing valve 60 are respectively connected to the rodless chamber 71 and the rod chamber 72 of the variable amplitude cylinder 70.

[0025] The variable amplitude balancing valve 60 includes a pressure reducing valve 61 , a first relief valve 62 , a throttle valve 63 , a second relief valve 64 and a one-way valve 65 .

[0026] Among them, the pressure reducing valve 61 is arranged on the oil circuit between the first oil port A1 and the third oil port A2; the oil inlet of the pressure reducing valve 61 is connected to the third oil port A2, the oil outlet is connected to the first oil port A1, and the control oil port is connected to the oil circuit between the second oil port B1 and the fourth oil port B2.

[0027] The oil inlet of the first relief valve 62 is connected to the oil path between the oil inlet of the pressure reducing valve 61 and the third oil port A2 , and the oil outlet is connected to the oil return port T1 of the luffing balancing valve 60 .

[0028] The throttle valve 63 is provided on the oil circuit at one end of the control oil port of the pressure reducing valve 61 . In this embodiment, the diameter of the damping hole of the throttle valve 63 is preferably 0.5 mm.

[0029] The second relief valve 64 is provided in the oil passage between the second oil port B1 and the fourth oil port B2 . The oil inlet of the second relief valve 64 is connected to the second oil port B1 , and the oil outlet is connected to the fourth oil port B2 .

[0030] The one-way valve 65 is arranged on the oil circuit between the oil outlet of the second relief valve 64 and the oil return port T1 of the variable amplitude balancing valve 60. The oil inlet of the one-way valve 65 is connected to the oil circuit between the oil outlet of the second relief valve 64 and the fourth oil port B2, and the oil outlet is connected to the oil return port T1 of the variable amplitude balancing valve 60.

[0031] The oil return port T1 of the luffing balancing valve 60 is connected to the oil tank 80 .

[0032] Furthermore, the control valve 50 includes a reversing valve 51 and a third relief valve 52. The reversing valve 51 is a three-position, six-way valve. Two of its oil inlets are connected to the oil inlet P of the control valve 50, and its oil return port is connected to the oil return port T of the control valve 50. Two of its three working oil ports are connected to the first and second working oil ports of the control valve 50, respectively, and another of its three working oil ports is connected to the oil return port T of the control valve 50. In this embodiment, the reversing valve 51 is a manually operated valve, i.e., it has a control handle that controls its switching between three working positions.

[0033] The reversing valve 51 has a neutral position, a first operating position, and a second operating position. When the reversing valve 51 is in the neutral position, one of the reversing valve's oil inlets is connected through a throttle hole inside the reversing valve 51 to a working oil port connected to the oil return port T of the control valve 50, and then to the oil tank 80. The other oil ports are disconnected. When the reversing valve 51 is in the first operating position on the left side of the figure, the return port and two oil inlets of the reversing valve 51 are in one-to-one communication with the three working oil ports, and hydraulic oil from the oil inlet P of the control valve 50 flows to the third oil port B1 of the boom balancing valve 60. When the reversing valve 51 is in the second operating position on the right side of the figure, the return port and two oil inlets of the reversing valve 51 are in one-to-one communication with the three working oil ports, and hydraulic oil from the oil inlet P of the control valve 50 flows to the first oil port A1 of the boom balancing valve 60.

[0034] The third relief valve 52 is connected to the oil passage between the oil inlet P and the oil return port T of the control valve 50 .

[0035] Furthermore, the second overflow valve 64 and the one-way valve 65 are both of plug-in type.

[0036] Furthermore, the luffing cylinder control system further includes an oil pump 90 , which is connected to the oil circuit between the oil inlet P of the control valve 50 and the oil tank 80 .

[0037] The working principle of the luffing cylinder control system is as follows: the luffing cylinder 70 raises / lowers the arm by changing the oil inlet and outlet direction of the rod chamber / rodless chamber of the luffing cylinder 70 through the control valve 50, thereby achieving the lifting angle of the boom.

[0038] Specifically, when the boom is raised, oil enters the rodless chamber 71 of the boom cylinder 70, and the hydraulic oil enters the valve through the first oil port A1 of the boom balancing valve 60 and then comes out from the third oil port A2 to enter the rodless chamber 71 of the boom cylinder 70, pushing the cylinder piston to lift the boom. At this time, the hydraulic oil in the rod chamber 72 of the boom cylinder 70 comes out and enters the valve through the fourth oil port B2 of the boom balancing valve 60. At this time, the second overflow valve 64 is in a closed state, the oil circuit is blocked, and the hydraulic oil can only come out from the return oil port T1 of the boom balancing valve 60 through the one-way valve 65 and directly return to the oil tank 80. When the boom is lowered, oil enters the rod chamber 72 of the boom cylinder 70, enters the valve from the second oil port B1 of the boom balancing valve 60, and then comes out from the fourth oil port B2 through the second relief valve 64 to enter the rod chamber 72 of the boom cylinder 70, pushing the cylinder piston to move toward the rodless chamber 71, thereby lowering the boom. At this time, the hydraulic oil in the rodless chamber 71 comes out and enters the third oil port A2 of the boom balancing valve 60, and then comes out from the first oil port A1 and returns to the oil tank 80 through the control valve 50. During the boom lowering process, the first relief valve 62 works, and the return oil establishes back pressure, so that the boom falls smoothly.

[0039] When the boom needs to be stabilized at a certain position, the control valve 50 is in the middle position. Since the load on the luffing balancing valve 60 is large, the hydraulic oil returns through the control valve 50 into the oil tank 80. The luffing balancing valve 60 locks the oil circuit of the luffing cylinder 70, keeping the luffing cylinder 70 stationary.

[0040] During the retraction process of the luffing cylinder 70 (that is, during boom lowering), hydraulic oil flows from the second oil port B1 to the fourth oil port B2. The throttle valve 63 opens the pressure reducing valve 61, connecting the oil path between the third oil port A2 and the first oil port A1. The hydraulic oil then returns to the tank through the control valve 50, forming a closed oil path. During this process, the hydraulic oil flows through the second relief valve 64, which ensures that the pressure of the hydraulic oil at the control port that opens the pressure reducing valve 61 remains constant. This ensures a stable opening of the relief valve 61 and effectively prevents vibration during luffing during lowering due to fluctuations in the hydraulic oil pressure at the control port of the pressure reducing valve 61 caused by unstable system pressure.

[0041] In the variable-length balancing valve 60, the first relief valve 62 plays a safety role to prevent the system pressure from being too high during the lowering of the boom. When the system pressure exceeds the set pressure of the first relief valve 62, the hydraulic oil opens the valve core of the first relief valve 62, and the excess hydraulic oil returns to the oil tank 80 for pressure relief.

[0042] In the boom balancing valve 60, the one-way valve 65 ensures that the hydraulic oil entering the boom balancing valve 60 through the oil pump 90 during the boom lowering process of the boom cylinder control system basically only serves to open the boom balancing valve 60. The entering hydraulic oil can directly return to the oil tank through the one-way valve 65, so that the boom lowering is basically achieved by the load's own weight.

[0043] The present invention further provides a lifting equipment including the above-mentioned luffing cylinder control system. Other structures of the lifting equipment are well known in the art and will not be described in detail here.

[0044] The present invention has the following beneficial effects: 1. It prevents the conventional variable-luffing balance valve from causing sudden jittering of the lifting equipment due to load changes during the descent process; 2. A buffer device with sufficient stability for the pilot control pressure signal is designed for the pilot control oil circuit of the balancing valve; 3. The added second relief valve 64 and one-way valve 65 are both plug-in type, which has little impact on the oil circuit of the entire variable amplitude balancing valve 60. In addition, the external dimensions of the variable amplitude balancing valve 60 remain basically unchanged compared with the prior art, and can be directly interchanged with little cost change.

[0045] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A variable amplitude cylinder control system, comprising a control valve (50), a variable amplitude balancing valve (60) and a variable amplitude cylinder (70), wherein the oil inlet P and the oil return port T of the control valve (50) are both connected to the oil tank (80), the first working oil port and the second working oil port of the control valve (50) are respectively connected to the first oil port A1 and the second oil port B1 of the variable amplitude balancing valve (60), and the third oil port A2 and the fourth oil port B2 of the variable amplitude balancing valve (60) are respectively connected to the rodless chamber (71) and the rod chamber (72) of the variable amplitude cylinder (70); characterized in that: The variable amplitude balancing valve (60) includes a pressure reducing valve (61), a first relief valve (62), a throttle valve (63), and a second relief valve (64); The pressure reducing valve (61) is arranged on the oil circuit between the first oil port A1 and the third oil port A2; the oil inlet of the pressure reducing valve (61) is connected to the third oil port A2, the oil outlet of the pressure reducing valve (61) is connected to the first oil port A1, and the control oil port of the pressure reducing valve (61) is connected to the oil circuit between the second oil port B1 and the fourth oil port B2; The oil inlet of the first overflow valve (62) is connected to the oil line between the oil inlet of the pressure reducing valve (61) and the third oil port A2, and the oil outlet of the first overflow valve (62) is connected to the oil return port T1 of the variable amplitude balancing valve (60); The throttle valve (63) is arranged on the oil circuit at one end of the control oil port of the pressure reducing valve (61); The second overflow valve (64) is provided on the oil path between the second oil port B1 and the fourth oil port B2, the oil inlet of the second overflow valve (64) is connected to the second oil port B1, and the oil outlet of the second overflow valve (64) is connected to the fourth oil port B2; and The oil return port T1 of the variable amplitude balancing valve (60) is connected back to the oil tank (80).

2. The luffing cylinder control system according to claim 1, characterized in that: The variable amplitude balancing valve (60) further comprises a one-way valve (65), wherein the one-way valve (65) is arranged on the oil path between the oil outlet of the second relief valve (64) and the oil return port T1 of the variable amplitude balancing valve (60).

3. The luffing cylinder control system according to claim 2, characterized in that: The second overflow valve (64) and the one-way valve (65) are both of plug-in type.

4. The luffing cylinder control system according to claim 1, characterized in that: The damping hole diameter of the throttle valve (63) is 0.5 mm.

5. The luffing cylinder control system according to claim 1, characterized in that: The control valve (50) includes a reversing valve (51), which is a three-position six-way valve. Two of the oil inlets of the reversing valve (51) are connected to the oil inlet P of the control valve (50), and the oil return port of the reversing valve (51) is connected to the oil return port T of the control valve (50). Two of the three working oil ports of the reversing valve (51) are respectively connected to the first working oil port and the second working oil port of the control valve (50), and another of the three working oil ports of the reversing valve (51) is connected to the oil return port T of the control valve (50).

6. The luffing cylinder control system according to claim 5, characterized in that: The control valve (50) further comprises a third overflow valve (52), wherein the third overflow valve (52) is connected to the oil circuit between the oil inlet P of the control valve (50) and the oil return port T of the control valve (50).

7. The luffing cylinder control system according to claim 5, characterized in that: The reversing valve (51) has a control handle.

8. The luffing cylinder control system according to claim 1, characterized in that: The luffing oil cylinder control system further comprises an oil pump (90), and the oil pump (90) is connected to the oil circuit between the oil inlet P of the control valve (50) and the oil tank (80).

9. A lifting equipment, characterized in that: It comprises the luffing cylinder control system according to any one of claims 1 to 8.

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