Loop switching valve, crawler crane chassis hydraulic system and crawler crane

Abstract

Disclosed is a loop switching valve, comprising a valve body and a valve core arranged in the valve body, wherein the valve core comprises a valve core oil drainage channel arranged in the valve core, and the valve body comprises an oil drainage port (L), a valve body oil drainage channel arranged in the valve body, and a plurality of oil inlets and working oil ports; and the oil inlet is in communication with the corresponding working oil port in a working state, the working oil port in a non-working state is in communication with the oil drainage port (L) by means of the valve core oil drainage channel and the valve body oil drainage channel, so as to discharge hydraulic oil from the working oil port in the non-working state, thereby preventing misoperation. The problems in the prior art of leakage, oil cross-flow and pressure building of a multi-way directional control valve during loop switching are solved, so that the reliability of the system is greatly improved, and the requirements for daily inspection and maintenance of apparatuses by an apparatus management user are also reduced. Further disclosed are a crawler crane chassis hydraulic system using the loop switching and a crawler crane.

Description

A circuit switching valve, a hydraulic system for a crawler crane chassis, and a crawler crane. Technical Field

[0001] This invention belongs to the field of crawler crane technology, specifically relating to a circuit switching valve, a crawler crane chassis hydraulic system, and a crawler crane. Background Technology

[0002] Tracked cranes currently primarily utilize hydraulic transmission for travel, winch operation, and disassembly / relocation. Operational functions include winching, luffing, slewing, and travel. Smaller tracked cranes under 100 tons typically have both wide-gauge and narrow-gauge chassis configurations. The narrow-gauge mode is suitable for operation in confined spaces, while the wide-gauge mode increases lifting capacity in wide spaces. Switching between wide-gauge and narrow-gauge modes is controlled by the extension and retraction of hydraulic cylinders. Disassembly / relocation of tracked cranes for transport typically involves lifting the chassis using outrigger cylinders, disassembling the track frame for separate transport to reduce maximum transport weight, or switching to narrow-gauge mode via the outrigger cylinders to directly load the crane onto a transport flatbed, reducing transport width. The chassis travel, wide-gauge / narrow-gauge switching, and outrigger movement are all achieved by the hydraulic system.

[0003] To achieve resource conservation and cost optimization during the manufacturing of crawler cranes, and to achieve fuel conservation during the use of crawler cranes, the design needs to minimize and control the weight, quantity, and complexity of components as much as possible. In particular, technical research on the hydraulic system components, which have relatively high value in crawler cranes, is especially important.

[0004] Therefore, reducing the number, weight, and system complexity of hydraulic pumps and valves in the hydraulic system of crawler cranes, reducing the connection complexity between the crawler crane chassis and turntable hydraulic system, and realizing the circuit switching between the travel circuit and the track changing circuit or the outrigger cylinder circuit through the circuit switching valve can effectively reduce the number of hydraulic pumps and valves, control weight, reduce system complexity, and achieve resource saving and cost optimization in the manufacturing of crawler cranes.

[0005] There are two main types of existing crawler crane chassis systems: independent multi-circuit hydraulic systems and chassis circuit switching hydraulic systems.

[0006] The chassis's independent multi-circuit hydraulic system includes the chassis travel motor circuit, the rail change cylinder circuit, or the outrigger cylinder circuit, which are controlled by multiple different pumps and control valves on the crawler crane turntable. Typically, the crawler crane turntable needs to be equipped with two or three sets of hydraulic pumps and corresponding two or three sets of control valves to form a hydraulic circuit. The central rotating body has a large number of channels, with eight channels in total.

[0007] In a hydraulic system with chassis circuit switching, the chassis travel motor circuit and the rail change cylinder circuit or outrigger cylinder circuit are switched between circuits through a circuit switching valve. This system is significantly superior to a chassis-independent multi-circuit hydraulic system in terms of reducing the number of components, weight, and design complexity. This system technology is widely used in crawler cranes with a production volume of less than 100 tons.

[0008] In this technology, the circuit switching valve is a key component. The system often uses imported multi-way directional valves (hydraulic switches) or domestically produced hydraulic valves with the same principle and structure. However, these hydraulic valves have the following disadvantages:

[0009] (1) Multi-way directional valves have a clearance between the valve stem and the valve body, and it is still impossible to achieve a completely zero leakage level. The clearance can generally only be controlled at 1 to 10 μm. When the clearance is too large during the manufacturing process, or when the circuit pressure increases, the internal leakage is large. There is a risk and disadvantage that the high-pressure oil in the working circuit may be transmitted to the non-working circuit. There is also the problem that the outrigger cylinder or the rail-changing cylinder may occasionally experience pressure build-up or slow automatic extension and retraction.

[0010] (2) There is a certain risk in the travel motor brake being engaged and the motor rotating slowly without any operation command being given. Moreover, when such risk phenomena are minor, they are often not visible to the naked eye, and therefore cannot be dealt with in time. Thus, there is a certain degree of occasional risk.

[0011] (3) When the crawler crane is subjected to drastic changes in ambient temperature, such as exposure to the sun or transportation from a low-temperature environment to a high-temperature environment, if the multi-way directional valve in the chassis hydraulic system has very good sealing performance, the hydraulic oil in the non-working circuit connected after the directional valve will not easily leak out, which will cause a certain degree of closed cavity phenomenon. At this time, the closed cavity will be affected by the temperature rise, and the temperature change will cause expansion. The hydraulic oil itself has a large elastic modulus, and the pressure in the rail change cylinder circuit or outrigger cylinder circuit will rise, which may also cause pressure buildup. This will cause the cylinder to slowly extend automatically without command or damage the cylinder seal and structural components. Such adverse phenomena have been found in the long-term product tracking process.

[0012] Summary of the Invention

[0013] To address the shortcomings of existing technologies, this invention provides a circuit switching valve, a crawler crane chassis hydraulic system, and a crawler crane. It solves the problems of leakage, oil cross-contamination, and pressure buildup in existing multi-way directional valves during circuit switching. It also resolves the risks of pressure buildup and extension / retraction of cylinders and motors in the crawler crane chassis hydraulic system caused by the circuit switching valve in non-command states. This significantly improves system reliability and reduces the requirements for daily inspection and maintenance by equipment management users.

[0014] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0015] In a first aspect, a circuit switching valve is provided, comprising: a valve body and a valve core disposed within the valve body, the valve core including a valve core drain channel disposed inside the valve core, the valve body including a drain port, a valve body drain channel disposed inside the valve body, a plurality of inlets and working ports; the inlets are connected to the corresponding working ports in the working state, and the working ports in the non-working state are connected to the drain ports through the valve core drain channel and the valve body drain channel, for discharging hydraulic oil from the working ports in the non-working state to prevent malfunction.

[0016] Furthermore, the valve core oil drain channel includes: a valve core oil drain annular groove communicating with the working oil port in the non-working state; a plurality of valve core radial oil drain holes communicating with the valve core oil drain annular groove; a valve core oil drain collection hole communicating with the valve core radial oil drain holes; and the valve core oil drain annular groove is configured to communicate with the valve body oil drain channel.

[0017] Furthermore, the valve body oil drain channel includes: a plurality of valve body radial oil drain holes communicating with the set valve core oil drain annular groove; a valve body oil drain annular groove communicating with the valve body radial oil drain holes; a valve body oil drain collection hole communicating with the valve body oil drain annular groove; and the valve body oil drain collection hole communicating with the oil drain port.

[0018] Furthermore, the oil inlet includes a first oil inlet and a second oil inlet, and the working oil inlet includes a first working oil inlet, a second working oil inlet, a third working oil inlet, and a fourth working oil inlet; the valve body is also provided with a control oil inlet for controlling the reversing of the valve core.

[0019] Furthermore, when there is no control pressure at the control port, the first oil inlet is connected to the first working oil port, the second oil inlet is connected to the second working oil port, and both the first and second working oil ports are in working condition; the third and fourth working oil ports are in non-working condition and are connected to the drain port through the valve core drain channel and the valve body drain channel, respectively.

[0020] Furthermore, when there is control pressure at the control port, the first oil inlet is connected to the third working oil port, the second oil inlet is connected to the fourth working oil port, and both the third and fourth working oil ports are in working condition; the first and second working oil ports are in non-working condition and are connected to the drain port through the valve core drain channel and the valve body drain channel, respectively.

[0021] In a second aspect, a hydraulic system for a crawler crane chassis is provided, comprising the circuit switching valve described in the first aspect, wherein the first oil inlet, the second oil inlet, the control oil inlet, and the unloading oil inlet of the circuit switching valve are respectively connected to the turntable hydraulic system; the first working oil inlet and the second working oil inlet of the circuit switching valve are respectively connected to the first working device; and the third working oil inlet and the fourth working oil inlet of the circuit switching valve are respectively connected to the second working device.

[0022] Furthermore, the first working device is a left travel motor, and the second working device is a rail-changing cylinder; or, the first working device is a left travel motor, and the second working device includes a chassis outrigger multi-way valve, which is connected to the outrigger cylinder and the rail-changing cylinder respectively.

[0023] Furthermore, when there is no control pressure at the control port, the first working device is in the working state; the second working device is in the non-working state. If the hydraulic oil in the first working device leaks into the second working device through the circuit switching valve, the hydraulic oil leaking into the second working device will be depressurized through the valve core drain channel, valve body drain channel and drain port in the circuit switching valve to prevent the second working device from malfunctioning.

[0024] Furthermore, when there is control pressure at the control port, the second working device is in the working state; the first working device is in the non-working state. If the hydraulic oil in the second working device leaks into the first working device through the circuit switching valve, the hydraulic oil leaking into the first working device will be depressurized through the valve core drain channel, valve body drain channel and drain port in the circuit switching valve to prevent the first working device from malfunctioning.

[0025] Thirdly, a crawler crane is provided, wherein the crawler crane is equipped with the crawler crane chassis hydraulic system described in the second aspect.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention uses a valve body and a valve core disposed within the valve body. The valve core includes a valve core drain channel disposed inside the valve core. The valve body includes a drain port, a valve body drain channel disposed inside the valve body, several inlets, and working ports. The inlets are connected to the corresponding working ports in the working state. The working ports in the non-working state are connected to the drain ports through the valve core drain channel and the valve body drain channel, which is used to discharge the hydraulic oil in the non-working ports and prevent malfunctions. The present invention solves the problems of leakage, oil cross-contamination, and pressure buildup in the circuit switching of multi-way directional valves in the prior art. It also solves the risk of pressure buildup and extension of cylinders and pressure buildup and rotation of motors in the non-command state caused by the circuit switching valve in the chassis hydraulic system of crawler cranes. This greatly improves the reliability of the system and reduces the requirements of equipment management users for daily inspection and maintenance. Attached Figure Description

[0027] Figure 1 is a schematic diagram of the structural principle of a loop switching valve provided in an embodiment of the present invention when there is no control pressure at the control end;

[0028] Figure 2 is a schematic diagram of the structural principle of a loop switching valve provided in an embodiment of the present invention when there is control pressure at the control end;

[0029] Figure 3 is a schematic diagram of the structural principle of the valve core in a loop switching valve provided in an embodiment of the present invention;

[0030] Figure 4 is a cross-sectional schematic diagram of a loop switching valve provided in an embodiment of the present invention when there is no control pressure at the control end;

[0031] Figure 5 is a cross-sectional schematic diagram of a loop switching valve provided in an embodiment of the present invention when there is control pressure at the control end;

[0032] Figure 6 is a schematic diagram of the hydraulic system of a tracked crane chassis provided in an embodiment of the present invention;

[0033] Figure 7 is a schematic diagram of the hydraulic system of a tracked crane chassis provided in an embodiment of the present invention.

[0034] In the diagram: L, drain port; P1, first oil inlet; P2, second oil inlet; A1, first working oil port; A2, second working oil port; C1, third working oil port; C2, fourth working oil port; PX, control oil port; 11, valve core drain annular groove; 12, valve core radial drain hole; 13, valve core drain collection hole; 22, valve body radial drain hole; 23, valve body drain collection hole. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0036] Example 1:

[0037] As shown in Figures 1 to 5, a circuit switching valve includes: a valve body and a valve core disposed within the valve body. The valve core includes a valve core drain channel disposed inside the valve core. The valve body includes a drain port L, a valve body drain channel disposed inside the valve body, several inlets, and working ports. The inlets are connected to the corresponding working ports in the working state. The working ports in the non-working state are connected to the drain port L through the valve core drain channel and the valve body drain channel, for discharging the hydraulic oil in the working ports in the non-working state to prevent malfunction.

[0038] In this invention, the oil inlet includes a first oil inlet P1 and a second oil inlet P2, and the working oil inlets include a first working oil inlet A1, a second working oil inlet A2, a third working oil inlet C1, and a fourth working oil inlet C2; the valve body is also provided with a control oil inlet PX for controlling the valve core reversing. The circuit switching valve of this invention has a two-position, six-way, multi-path reversing function, and reversing is achieved through hydraulic pilot pressure.

[0039] As shown in Figure 1, when there is no control pressure at the control port PX, the first inlet port P1 is connected to the first working port A1, and the second inlet port P2 is connected to the second working port A2. Both the first working port A1 and the second working port A2 are in working condition. The third working port C1 and the fourth working port C2 are in non-working condition and are connected to the drain port L through the damping channel (valve core drain channel) on the valve core and the damping channel (valve body drain channel) on the valve body, respectively.

[0040] As shown in Figure 2, when the control port PX has control pressure, the first inlet port P1 is connected to the third working port C1, the second inlet port P2 is connected to the fourth working port C2, and both the third working port C1 and the fourth working port C2 are in working condition; the first working port A1 and the second working port A2 are both in non-working condition, and are connected to the drain port L through the valve core drain channel and the valve body drain channel, respectively.

[0041] The dual oil drain channel combination structure, consisting of a damping channel on the valve core and a damping channel on the valve body, provided by this invention, completely solves the shortcomings of the prior art. The pressure of the oil port in the non-working state flows into the damping channel on the valve body through the damping channel on the valve core, and is finally released at the oil drain port L.

[0042] As shown in Figures 3 to 5, the specific structure of the dual oil drain channel combination is as follows:

[0043] The valve core drain channel includes: a valve core drain annular groove 11 connected to the working oil port in the non-working state; a plurality of valve core radial drain holes 12 connected to the valve core drain annular groove 11; a valve core drain collection hole 13 connected to the valve core radial drain holes 12; and the valve core drain annular groove 11 is connected to the valve body drain channel L2.

[0044] As shown in Figure 3, the valve core drain channel is composed of three sets of valve core drain annular grooves 11, three sets of valve core radial drain holes 12, and valve core drain collection holes 13. The valve core drain annular grooves 11 located at both ends of the valve core are connected to the valve body drain channel.

[0045] The valve body oil drain channel includes: a plurality of valve body radial oil drain holes 22 connected to the set valve core oil drain annular groove 11; valve body oil drain annular groove connected to the valve body radial oil drain holes 22; valve body oil drain collection hole 23 connected to the valve body oil drain annular groove; and valve body oil drain collection hole 23 connected to the oil drain port L.

[0046] The circuit switching valve of this invention, with its dual drain channel combination structure, exists in two states, summarized in Table 1:

[0047] Table 1 Comparison of two operating states of a circuit switching valve with a dual drain channel combination structure

[0048] This invention solves the problems of leakage, oil cross-contamination, and pressure buildup in the circuit switching of existing multi-way directional valves by using a circuit switching valve with a dual-drainage channel combination structure. It also solves the risk of pressure buildup and extension / retraction of cylinders and pressure buildup and rotation of motors in the chassis hydraulic system of crawler cranes caused by the circuit switching valve in non-command states. This greatly improves the reliability of the system and reduces the requirements of equipment management users for daily inspection and maintenance.

[0049] Example 2:

[0050] Based on the circuit switching valve described in Embodiment 1, this embodiment provides a hydraulic system for a crawler crane chassis. The first oil inlet P1, the second oil inlet P2, the control oil inlet PX, and the unloading oil inlet L of the circuit switching valve are respectively connected to the turntable hydraulic system; the first working oil inlet A1 and the second working oil inlet A2 of the circuit switching valve are respectively connected to the first working device; and the third working oil inlet C1 and the fourth working oil inlet C2 of the circuit switching valve are respectively connected to the second working device.

[0051] As shown in Figure 6, the first working device is the left travel motor, and the second working device is the track-changing cylinder. When the control port PX has no working pressure, during travel operation, the hydraulic pressure in the travel motor circuit A1 / A2 may be connected to the track-changing cylinder C1 / C2. This hydraulic pressure is then connected to the drain port L through the dual drain channels of the circuit switching valve, achieving hydraulic pressure relief and preventing malfunction of the track-changing cylinder. When the control port PX has working pressure, and the track-changing cylinder is working, the hydraulic pressure in C1 / C2 may be connected to A1 / A2. This hydraulic pressure is then connected to the drain port L through the dual drain channels of the circuit switching valve, achieving hydraulic pressure relief and preventing malfunction of the travel motor.

[0052] As shown in Figure 7, the first working device is a left travel motor, and the second working device includes a chassis outrigger multi-way valve, which is connected to the outrigger cylinder and the track-changing cylinder respectively. When the control port PX has no working pressure, during travel operation, the hydraulic pressure of the travel motor circuit A1 / A2 may be connected to the track-changing cylinder C1 / C2. This hydraulic pressure is then connected to the unloading port L through the dual drain channels of the circuit switching valve, achieving oil drainage and pressure relief, and preventing malfunctions of the track-changing cylinder and the outrigger cylinder. When the control port PX has working pressure, and the track-changing cylinder or the outrigger cylinder is working, the hydraulic pressure of C1 / C2 may be connected to A1 / A2. This hydraulic pressure is then connected to the unloading port L through the dual drain channels of the circuit switching valve, achieving oil drainage and pressure relief, and preventing malfunctions of the travel motor.

[0053] The circuit switching valve principle, dual drain channel combination structure, and crawler crane chassis hydraulic system proposed in this invention have the following advantages:

[0054] a) The circuit switching valve solves the problems caused by leakage, oil cross-contamination, and pressure buildup between the oil ports of traditional multi-way directional valves in principle.

[0055] b) The dual-drainage combination structure cleverly realizes the safe pressure relief and oil discharge function of four oil ports through the three sets of oil discharge annular grooves, three sets of radial oil discharge holes, oil discharge collection holes and oil discharge channels on the valve body, and the combination of these features when switching between the two working states of the valve.

[0056] c) The hydraulic system of the tracked crane chassis in this invention solves the risk of cylinder pressure buildup and extension / retraction, and motor pressure buildup and rotation caused by the circuit switching valve in the chassis hydraulic system, which is not under command. This greatly improves the reliability of the system and reduces the requirements of equipment management users for daily inspection and maintenance.

[0057] Example 3:

[0058] Based on the circuit switching valve described in Embodiment 1 and the crawler crane chassis hydraulic system described in Embodiment 2, this embodiment provides a crawler crane, which is equipped with the circuit switching valve described in Embodiment 1 or the crawler crane chassis hydraulic system described in Embodiment 2.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A circuit switching valve, characterized in that, include: The valve body and the valve core disposed in the valve body, the valve core including the valve core drain channel disposed inside the valve core, the valve body including the drain port (L), the valve body drain channel disposed inside the valve body, a plurality of oil inlets and working oil ports; The oil inlet is connected to the corresponding working oil port in the working state. The working oil port in the non-working state is connected to the drain port (L) through the valve core drain channel and the valve body drain channel. This is used to discharge the hydraulic oil in the working oil port in the non-working state to prevent malfunction.

2. The circuit switching valve according to claim 1, characterized in that, The valve core oil drain channel includes: The valve core drain annular groove (11) is connected to the working oil port when it is not in operation; A plurality of radial drain holes (12) of the valve core are connected to the annular groove (11) of the valve core; A valve core drain collection hole (13) that communicates with the radial drain hole (12) of the valve core; The valve core drain annular groove (11) is connected to the valve body drain channel L2.

3. The circuit switching valve according to claim 2, characterized in that, The valve body oil drain channel includes: A plurality of radial drain holes (22) of the valve body are connected to the set valve core drain annular groove (11); An annular groove for draining oil from the valve body that communicates with the radial drain hole (22) of the valve body; The valve body drain collection hole (23) is connected to the valve body drain annular groove; The valve body oil drain collection hole (23) is connected to the oil drain port (L).

4. The circuit switching valve according to claim 3, characterized in that, The oil inlet includes a first oil inlet (P1) and a second oil inlet (P2), and the working oil inlet includes a first working oil inlet (A1), a second working oil inlet (A2), a third working oil inlet (C1), and a fourth working oil inlet (C2); the valve body is also provided with a control oil inlet (PX) for controlling the reversing of the valve core.

5. The circuit switching valve according to claim 4, characterized in that, When there is no control pressure at the control port (PX), the first inlet port (P1) is connected to the first working port (A1), and the second inlet port (P2) is connected to the second working port (A2). Both the first working port (A1) and the second working port (A2) are in the working state. The third working port (C1) and the fourth working port (C2) are in the non-working state and are connected to the drain port (L) through the valve core drain channel and the valve body drain channel, respectively. Pass.

6. The circuit switching valve according to claim 4, characterized in that, When the control port (PX) has control pressure, the first inlet port (P1) is connected to the third working port (C1), the second inlet port (P2) is connected to the fourth working port (C2), and both the third working port (C1) and the fourth working port (C2) are in working condition; the first working port (A1) and the second working port (A2) are both in non-working condition and are connected to the drain port (L) through the valve core drain channel and the valve body drain channel, respectively.

7. A hydraulic system for a crawler crane chassis, characterized in that, Including the circuit switching valve as described in any one of claims 4 to 6, The first inlet (P1), second inlet (P2), control port (PX), and unloading port (L) of the circuit switching valve are respectively connected to the turntable hydraulic system; the first working port (A1) and second working port (A2) of the circuit switching valve are respectively connected to the first working device; and the third working port (C1) and fourth working port (C2) of the circuit switching valve are respectively connected to the second working device.

8. The hydraulic system for a tracked crane chassis according to claim 7, characterized in that, The first working device is a left travel motor, and the second working device is a rail-changing cylinder; Alternatively, the first working device is a left-side travel motor, and the second working device includes a chassis outrigger multi-way valve, which is connected to the outrigger cylinder and the rail-changing cylinder respectively.

9. The hydraulic system for a tracked crane chassis according to claim 7, characterized in that, When there is no control pressure at the control port (PX), the first working device is in the working state; the second working device is in the non-working state. If the hydraulic oil in the first working device leaks into the second working device through the circuit switching valve, the hydraulic oil leaking into the second working device will be depressurized through the valve core drain channel, valve body drain channel and drain port (L) in the circuit switching valve to prevent the second working device from malfunctioning.

10. The hydraulic system for a tracked crane chassis according to claim 7, characterized in that, When the control port (PX) has control pressure, the second working device is in working condition; the first working device is in non-working condition. If the hydraulic oil in the second working device leaks into the first working device through the circuit switching valve, the hydraulic oil leaking into the first working device will be depressurized through the valve core drain channel, valve body drain channel and drain port (L) in the circuit switching valve to prevent the first working device from malfunctioning.

11. A crawler crane, characterized in that, The crawler crane is equipped with the crawler crane chassis hydraulic system as described in any one of claims 7 to 10.

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