Crane low-speed control hydraulic system and crane

Abstract

The utility model relates to the technical field of crane hydraulic control, in particular to a crane low-speed control hydraulic system and a crane, and the low-speed control hydraulic system comprises a hydraulic oil tank, a variable pump, an operating handle, a hydraulic shuttle valve, a pressure sensor, a main control valve, a proportional electromagnetic valve and an execution element. According to the utility model, on the premise that the control curve of the original hydraulic control handle is not changed, the speed of the whole crane is reduced according to the set percentage and the selection of a user, so that the requirements of accuracy and stability in the hoisting process are met. The control system has the characteristics of wide adjustment range at low speed, good control comfort, high movement stability and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of crane hydraulic control, and in particular provides a crane low-speed control hydraulic system and a crane. Background Art

[0002] Cranes are widely used in the field of engineering lifting. When lifting dangerous goods, heavy loads, and performing installation work, the crane is required to have a lower operating speed or even a micro speed for safety, reliability, and precise positioning. This requires the crane to have a wide speed regulation range. However, the hydraulic system of the hydraulically controlled crane currently only controls the speed by pushing the angle of the hydraulic handle. The accuracy is insufficient at low speed control, the main machine movement is not smooth enough, and the control comfort is poor, which makes it difficult to meet the requirements of accuracy and stability during the lifting process. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides a low-speed control hydraulic system for a crane and a crane. The hydraulic system can reduce the speed of the entire crane by a set percentage according to user selection without changing the control curve of the original hydraulic control handle, thereby meeting the requirements of accuracy and stability during the lifting process. The system has the characteristics of a wide adjustment range at low speed, good control comfort and strong movement stability.

[0004] The utility model is implemented in this way, providing a low-speed control hydraulic system for a crane, including a hydraulic oil tank, a variable pump, an operating handle, a hydraulic shuttle valve, a pressure sensor, a proportional solenoid valve, a main control valve and an actuator, wherein the P port of the operating handle is connected to the A3 port of the variable pump, the A port, the B port, the C port and the D port of the operating handle are respectively connected to the A1 port, the A2 port, the A3 port and the A4 port of the hydraulic shuttle valve, the B1 port, the B2 port, the B3 port and the B4 port of the hydraulic shuttle valve are connected to the a1 port, the a2 port, the a3 port and the a4 port of the main control valve, and the M port of the hydraulic shuttle valve is connected to the The pressure sensor is connected, the proportional solenoid valve includes a two-position three-way solenoid valve and a solenoid proportional pressure reducing valve connected together, the a port of the hydraulic shuttle valve is connected to the P port of the solenoid proportional pressure reducing valve, the A port of the two-position three-way solenoid valve is connected to the Pi1 port and Pi2 port of the variable pump, the A1 port and A2 port of the variable pump are connected to the P1 port and P2 port of the main control valve, the A port and B port of the main control valve are connected to the A port and B port of the actuator, the T port of the operating handle, the T port of the proportional solenoid valve, the T1 port and T2 port of the main control valve, the oil suction port and the leakage port of the variable pump are all connected to the hydraulic oil tank.

[0005] Preferably, the variable pump comprises a pilot pump, a first main pump and a second main pump, and the pilot pump is fixed to the auxiliary output ports of the first main pump and the second main pump through flange connections.

[0006] Further preferably, the A1 port and the Pi1 port of the variable pump are located on the second main pump, the A2 port and the Pi2 port of the variable pump are located on the first main pump, and the A3 port and the a4 port of the variable pump are located on the pilot pump.

[0007] Further preferably, the electromagnetic proportional pressure reducing valve is an inverse proportional pressure reducing valve.

[0008] Further preferably, the Pi1 port of the variable pump is provided with a three-way connector, which is connected to the Pi2 port through a hydraulic hose and is connected to the A port of the proportional solenoid valve.

[0009] The utility model also provides a crane, which is provided with the above-mentioned crane low-speed control hydraulic system.

[0010] Compared with the prior art, the advantages of the utility model are:

[0011] The utility model provides a low-speed control hydraulic system for a crane and a crane. According to the user's selection of speed requirements, the value of a pressure sensor is collected to perform relevant calculations and output corresponding currents, and a proportional solenoid valve is controlled to achieve proportional reduction of the crane speed or micro-speed control to meet the requirements of accuracy and stability during the hoisting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is further described in detail below with reference to the accompanying drawings and implementation modes:

[0013] Figure 1 A structural diagram of a hydraulic system provided in Example 1 of the utility model;

[0014] Figure 2 This is a hydraulic system control flow chart provided for Example 1 of the utility model. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0016] Embodiment 1,

[0017] refer to Figure 1 and Figure 2The present embodiment provides a low-speed control hydraulic system for a crane, including a hydraulic oil tank 1, a variable pump 2, an operating handle 3, a hydraulic shuttle valve 4, a pressure sensor 5, a proportional solenoid valve 6, a main control valve 7 and an actuator 8. The P port of the operating handle 3 is connected to the A3 port of the variable pump 2 to provide pilot pressure oil to the operating system. The A port, B port, C port and D port of the operating handle 3 are respectively connected to the A1 port, A2 port, A3 port and A4 port of the hydraulic shuttle valve 4. The B1 port, B2 port, B3 port and B4 port of the hydraulic shuttle valve 4 are connected to the a1 port, a2 port, a3 port and a4 port of the main control valve 7. The M port of the hydraulic shuttle valve 4 is connected to the The pressure sensor 5 and the proportional solenoid valve 6 include a two-position three-way solenoid valve 6.1 and a solenoid proportional pressure reducing valve 6.2 connected together; the a port of the hydraulic shuttle valve 4 is connected to the P port of the solenoid proportional pressure reducing valve 6.2; the A port of the two-position three-way solenoid valve 6.1 is connected to the Pi1 port and the Pi2 port of the variable pump 2; the A1 port and the A2 port of the variable pump 2 are connected to the P1 port and the P2 port of the main control valve 7; the A port and the B port of the main control valve 7 are connected to the A port and the B port of the actuator 8; the T port of the operating handle 3, the T port of the proportional solenoid valve 6, the T1 port and the T2 port of the main control valve 7, and the oil suction port and the leakage port of the variable pump 2 are all connected to the hydraulic oil tank 1.

[0018] When the utility model is used to control the normal operation of the crane, the following steps are included:

[0019] 1. The two-position three-way solenoid valve 6.1 and the solenoid proportional pressure reducing valve 6.2 are both de-energized, and the operating handle 3 is pushed to transmit the signal to the Pi1 port and Pi2 port of the variable pump 2 through the signal output of the hydraulic shuttle valve 4 and the proportional solenoid valve 6;

[0020] 2. At this time, the output oil control of the variable pump 2's Pi1 and Pi2 ports on the variable pump 2's A1 and A2 ports is not affected by the proportional solenoid valve 6. The variable pump 2's A1 and A2 ports normally output signals to the main control valve 7's P1 and P2 ports.

[0021] 3. The main control valve 7 controls the actuator 8 according to the received signal, and the actuator 8 controls the speed of the crane. At this time, the speed of the crane is proportional to the pushing angle of the operating handle 3.

[0022] When the utility model is used to control the crane at a low speed, the following steps are included:

[0023] 1. The two-position three-way solenoid valve 6.1 is in the de-energized state, and the solenoid proportional pressure reducing valve 6.2 is in the energized state. Select the required speed regulating gear, for example, the gears can be 10%, 20%, 30%, 40%, and 50%, and transmit the speed regulating gear signal to the solenoid proportional pressure reducing valve 6.2;

[0024] 2. Push the operating handle 3. At this time, the pressure sensor 5 located at the M port of the hydraulic shuttle valve 4 will detect the pressure signal output by the operating handle 3 in real time, convert the pressure signal into a current signal through calculation and control the electromagnetic proportional pressure reducing valve 6.2 to perform secondary pressure reduction of the control pressure. The pressure reduction ratio depends on the speed gear selected in step 1.

[0025] 3. The electromagnetic proportional pressure reducing valve 6.2 transmits the speed-regulated signal to the Pi1 port and Pi2 port of the variable pump 2. The Pi1 port and Pi2 port proportionally control the output oil of the A1 port and A2 port of the variable pump 2. The A1 port and A2 port of the variable pump 2 output signals to the P1 port and P2 port of the main control valve 7 according to the proportional signal.

[0026] 4. The main control valve 7 controls the actuator 8 according to the received signal, and the actuator 8 controls the speed of the crane. At this time, the speed of the crane is the speed corresponding to the angle of the operating handle 3 under normal operation × the percentage of the selected speed gear.

[0027] In traditional hydraulic systems, speed regulation is achieved only by changing the angle of the operating handle, and the lower the speed, the smaller the handle angle, which results in a smaller control range in the low-speed area, making it difficult to meet the user's needs for low-speed control, and the control comfort is poor when the handle angle is small. However, the new type can reduce the speed of the entire crane by a set percentage through speed selection without changing the original hydraulic control handle control curve, which ensures the comfort of control and meets the low-speed control requirements and increases the low-speed control range.

[0028] When the utility model is used to perform micro-speed control on a crane, the following steps are included:

[0029] 1) The two-position three-way solenoid valve 6.1 is in the energized state, and the solenoid proportional pressure reducing valve 6.2 is in the de-energized state;

[0030] 2) After pushing the operating handle 3, the pressure oil in the variable cylinder of the variable pump 2 returns to the oil tank 1 through the T port of the proportional solenoid valve 6 through the signal output of the hydraulic shuttle valve 4 and the proportional solenoid valve 6. Since the pressure in the variable cylinder of the variable pump 2 is zero, the variable mechanism inside the pump will push the variable swash plate of the variable pump 2 to swing to the minimum displacement. At this time, the pump group will output the minimum displacement under this working pressure to meet the minimum speed requirement of the crane, and no matter how the angle of the operating handle 3 changes, the crane maintains the minimum speed unchanged.

[0031] As a specific arrangement of the variable pump 2, the variable pump 2 comprises a pilot pump 2.1, a first main pump 2.2 and a second main pump 2.3, and the pilot pump 2.1 is fixed to the auxiliary output ports of the first main pump 2.2 and the second main pump 2.3 through flange connection.

[0032] The pilot pump 2.1 is used to provide pilot control pressure oil to the operating handle 3. The first main pump 2.2 and the second main pump 2.3 respectively control the output oil of the variable pump 2 to give a signal to the main control valve 7.

[0033] Preferably, the A1 port and Pi1 port of the variable pump 2 are located on the second main pump 2.3, the A2 port and Pi2 port of the variable pump 2 are located on the first main pump 2.2, and the A3 port and a4 port of the variable pump 2 are located on the pilot pump 2.1.

[0034] Preferably, the electromagnetic proportional pressure reducing valve 6.2 is an inverse proportional pressure reducing valve.

[0035] In order to facilitate the connection between the Pi1 port and the Pi2 port of the variable pump 2 and the proportional solenoid valve 6, as an improvement of the technical solution, the Pi1 port of the variable pump 2 is provided with a three-way connector, which is connected to the Pi2 port through a hydraulic hose and connected to the A port of the proportional solenoid valve 6.

[0036] Embodiment 2,

[0037] This embodiment provides a crane equipped with the low-speed control hydraulic system described in Embodiment 1.

[0038] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A hydraulic system for low-speed control of a crane, It is characterized in that The invention comprises a hydraulic oil tank (1), a variable pump (2), an operating handle (3), a hydraulic shuttle valve (4), a pressure sensor (5), a proportional solenoid valve (6), a main control valve (7) and an actuator (8), wherein the P port of the operating handle (3) is connected to the A3 port of the variable pump (2), the A port, the B port, the C port and the D port of the operating handle (3) are respectively connected to the A1 port, the A2 port, the A3 port and the A4 port of the hydraulic shuttle valve (4), the B1 port, the B2 port, the B3 port and the B4 port of the hydraulic shuttle valve (4) are connected to the a1 port, the a2 port, the a3 port and the a4 port of the main control valve (7), the M port of the hydraulic shuttle valve (4) is connected to the pressure sensor (5), and the proportional solenoid valve (6) comprises a connecting The two-position three-way solenoid valve (6.1) and the solenoid proportional pressure reducing valve (6.2) are connected together, the port a of the hydraulic shuttle valve (4) is connected to the port P of the solenoid proportional pressure reducing valve (6.2), the port A of the two-position three-way solenoid valve (6.1) is connected to the ports Pi1 and Pi2 of the variable pump (2), the ports A1 and A2 of the variable pump (2) are connected to the ports P1 and P2 of the main control valve (7), the ports A and B of the main control valve (7) are connected to the ports A and B of the actuator (8), the port T of the operating handle (3), the port T of the proportional solenoid valve (6), the ports T1 and T2 of the main control valve (7), the oil suction port and the leakage port of the variable pump (2) are all connected to the hydraulic oil tank (1).

2. The crane low speed control hydraulic system according to claim 1, It is characterized in that The variable displacement pump (2) comprises a pilot pump (2.1), a first main pump (2.2) and a second main pump (2.3); the pilot pump (2.1) is fixed to the auxiliary output ports of the first main pump (2.2) and the second main pump (2.3) via flange connections.

3. The crane low speed control hydraulic system according to claim 2, It is characterized in that The A1 port and the Pi1 port of the variable pump (2) are located on the second main pump (2.3), the A2 port and the Pi2 port of the variable pump (2) are located on the first main pump (2.2), and the A3 port and the A4 port of the variable pump (2) are located on the pilot pump (2.1).

4. The crane low speed control hydraulic system according to claim 1, It is characterized in that The electromagnetic proportional pressure reducing valve (6.2) is a reverse proportional pressure reducing valve.

5. The crane low speed control hydraulic system according to claim 1, It is characterized in that The Pi1 port of the variable pump (2) is provided with a three-way joint, which is connected to the Pi2 port via a hydraulic hose and is connected to the A port of the proportional solenoid valve (6).

6. A crane, It is characterized in that A crane low-speed control hydraulic system is provided as described in any one of claims 1-5.

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