Compact flow distribution valve based on truck-mounted crane double-pump system

Abstract

The invention relates to a compact flow distribution valve based on a truck-mounted crane double-pump system, which comprises a control valve provided with a P port, a P'port and a T port, the P port is communicated with a control oil path of an action executing mechanism, and the T port is communicated with an oil return channel; the overflow valve is communicated with the control valve and the oil return channel; the confluence valve is communicated with the small pump, the large pump, the P'port of the control valve and the oil return channel, and a confluence valve element of the confluence valve acts based on the oil output state of the P 'port of the control valve to be opened and closed; when the pressure of the oil liquid introduced into the control valve does not exceed the overflow pressure of the control valve, the control valve conducts the P port and the P'port; and when the pressure of the oil liquid introduced into the control valve exceeds the overflow pressure, the control valve conducts the P'port and the T port. The compact flow distribution valve based on the truck-mounted crane double-pump system does not need to be provided with electric devices such as a pressure sensor and an electromagnetic valve, and can solve the problems that the system is large in heat productivity and not energy-saving and environment-friendly due to high-pressure unloading of a small pump and potential safety hazards are caused by flameout of an engine.

Description

Technical Field

[0001] The invention relates to a compact flow distribution valve based on a truck-mounted crane dual-pump system. Background Art

[0002] With the continuous development and growth of construction machinery, the technical requirements for vehicle hydraulic systems are becoming increasingly stringent. At the same time, the control and components of each actuator are required to be highly integrated, compact, and reduce operator fatigue. For example, in the field of construction machinery truck-mounted cranes, to improve efficiency and operational smoothness, more and more manufacturers are optimizing the system's main pump from a single pump to a dual pump, and requiring the winch and boom pumps to merge to enhance efficiency. However, under heavy load conditions, the small pump cannot open the check valve due to the pressure limit of the main relief valve, and cannot participate in the merging. Typically, the main relief valve pressure of the small pump is set at 21MPa, and the main relief valve pressure of the large pump is set at 26MPa. When the merging valve core is open, the load-sensing pressure also merges, and the load-sensing pressure of the small pump is not cut off. The oil in the small pump can only operate and heat up. In some special-purpose vehicle engines, insufficient torque can cause the vehicle to stall. This can also lead to: 1. Excessive and rapid temperature rise in the hydraulic system, reducing efficiency and shortening the service life of hydraulic components; 2. Sudden engine shutdown during lifting operations, posing safety risks such as rollover, boom collapse, and wire rope breakage.

[0003] To address the above issues, some countermeasures were adopted based on the post-valve compensation LUDV flow distribution valve: 1. Using a pressure sensor and solenoid valve, when the control pressure for controlling the switching of the converging valve core reaches 16MPa, the solenoid valve is energized and unloaded, the converging valve core is closed, the small pump does not participate in the converging, the main channel and the load-sensitive channel do not merge, and the oil of the small pump is unloaded at low pressure through the three-way flow valve. However, such a system has more pipes and more complex electronic control parts. Insufficient sensor accuracy can cause the converging valve core to float, sometimes the converging action suddenly speeds up, and sometimes the non-converging action suddenly slows down, making the execution unstable and unsafe. In addition, the oil unloaded by the solenoid valve is the oil in the working flow channel, which further reduces work efficiency. 2. Using multiple pressure sensors and solenoid valves and switching the valve core to converging in the initial state. The swing pressure signal closes the merging valve spool. During swing operation, when the swing pressure reaches 2 MPa, pressure sensor 1 opens, energizing the solenoid valve. The control pressure pushes the merging valve spool open, disconnecting the two pumps from merging. When the main pump's operating pressure reaches 16 MPa, pressure sensor 2 opens, energizing the solenoid valve. The control pressure pushes the merging valve spool open, disconnecting the two pumps from merging. When the main pump's operating pressure drops below 10 MPa, pressure sensor 3 opens, de-energizing the solenoid valve. The merging valve spool returns to its original position under spring force, allowing the two pumps to merge. This solution further complicates the electrical system, and the electrical portion of the hydraulic system has a higher failure rate than the hydraulic portion. The hydraulic principle of direct merging of the two pumps results in excess oil being unloaded at high pressure during movements such as lowering and retracting that do not require such high flow, increasing heat generation. The three pressure sensors are integrated into the multi-way valve, and the wiring harness is also connected to the operator's cab, which is already quite small, further compromising operator comfort. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a compact flow distribution valve based on a truck crane dual-pump system, which does not require the installation of pressure sensors, solenoid valves and other electrical components, and can solve the problems of high system heat generation caused by high pressure unloading of small pumps, which is not energy-saving and environmentally friendly, and safety hazards caused by engine stalling.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a compact flow distribution valve based on a truck crane dual pump system, characterized in that:

[0006] The control valve has a P port, a P' port, and a T port, wherein the P port is connected to the control oil circuit of the actuator, and the T port is connected to the oil return channel;

[0007] The overflow valve is connected with the control valve and the oil return channel respectively;

[0008] The merging valve is connected to the small pump, the large pump, the P' port of the control valve, and the oil return channel respectively. The merging valve core of the merging valve is actuated based on the oil output state of the control valve P' port to realize the merging and diversion of the hydraulic oil pumped into the small pump and the large pump;

[0009] A one-way valve is provided on the oil path connecting the small pump and the merging valve;

[0010] When the oil pressure entering the control valve does not exceed its overflow pressure, the control valve core of the control valve will move to connect the P port and the P' port; when the oil pressure entering the control valve exceeds its overflow pressure, the control valve core of the control valve will move to connect the P' port and the T port.

[0011] In order to better control the communication relationship between the actuator and the control valve, a shuttle valve is also included. The inlet of the shuttle valve is connected to the oil circuit of the action actuator, and the outlet of the shuttle valve is connected to the P port of the control valve through the oil circuit.

[0012] Preferably, the action execution mechanism includes a hoisting mechanism and a telescopic mechanism, and a shuttle valve is respectively provided corresponding to the hoisting mechanism and the telescopic mechanism.

[0013] Preferably, a filter is provided on the oil path connecting the shuttle valve and the control valve.

[0014] The volume is smaller and the arrangement of pipelines and electrical components is simplified. The control valve, the overflow valve, the combining valve, the one-way valve and the shuttle valve are integrated in one valve body.

[0015] Preferably, the valve body is provided with a first flow channel extending in the left-right direction, the control valve core is arranged in the first flow channel, the P port, P' port and T port are arranged in sequence from left to right, and the right end of the first flow channel is provided with a spring acting on the control valve core.

[0016] In order to achieve a smooth switching action of the control valve, limit the return oil flow of the relief valve, minimize the reduction of the oil volume in the working flow channel, and improve working efficiency, a first damping orifice and a second damping orifice are provided at both ends of the first flow channel. The first damping orifice and the second damping orifice are respectively connected to the P port through the oil channel; the second damping orifice is arranged near the spring and is connected to the inlet of the relief valve;

[0017] The cross-sectional area of ​​the first damping hole is greater than the cross-sectional area of ​​the second damping hole.

[0018] In order to ensure the working stability of the action actuator, load-sensitive flow channels are connected between the merging valve and the oil return channel corresponding to the small pump and the large pump respectively, and damping holes are provided on the load-sensitive flow channels.

[0019] In order to adapt to different working conditions, the relief valve is a relief valve with adjustable set pressure.

[0020] Compared with existing technologies, the present invention offers the following advantages: The compact flow distribution valve based on the dual-pump system for a truck-mounted crane can achieve flow diversion and merging between the small and large pumps, ensuring low-pressure unloading of the small pump under heavy load conditions, preventing excessive and rapid temperature rise. This is more energy-efficient and environmentally friendly, and also avoids safety hazards caused by engine stalling. This compact flow distribution valve based on the dual-pump system for a truck-mounted crane eliminates the need for additional pressure sensors and solenoid valve components, thus preventing electrical failures during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a compact flow distribution valve based on a truck-mounted crane dual-pump system in an embodiment of the present invention.

[0022] Figure 2 This is a longitudinal sectional view from the main perspective of a compact flow distribution valve based on a truck-mounted crane dual-pump system in an embodiment of the present invention.

[0023] Figure 3 It is a longitudinal cross-sectional view from a side perspective of a compact flow distribution valve based on a truck-mounted crane dual-pump system in an embodiment of the present invention.

[0024] Figure 4 It is a cross-sectional view of a horizontal section of a compact flow distribution valve based on a truck-mounted crane dual-pump system in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0026] The dual-pump system of the truck crane includes a hoisting mechanism, a telescopic mechanism and other action mechanisms. As described in the background technology, the dual-pump system of the truck crane includes a large pump 400 and a small pump 300. The dual-pump system of the truck crane works in conjunction with the compact flow distribution valve based on the dual-pump system of the truck crane in this embodiment, so that when the hoisting mechanism is hoisting and the telescopic mechanism is telescoping, the large pump 400 and the small pump 300 work together in the early stage of the action, and drive the hoisting mechanism and the telescopic mechanism to move with a larger hydraulic action, thereby increasing the action speed and improving work efficiency. In the later stage of the action, the small pump 300 needs to be diverted and stopped working, and only the large pump 400 can be kept working, which can ensure the smoothness of the action and avoid the oil in the small pump 300 from being heated only during operation, solving the problem of affecting efficiency and service life due to excessive and rapid temperature rise, and also solving the safety hazards such as overturning, arm folding and wire rope breakage caused by sudden engine shutdown during the lifting operation.

[0027] like Figures 1 to 4As shown, the compact flow distribution valve for a truck-mounted crane dual-pump system in this embodiment includes a control valve 1, a relief valve 2, a combining valve 3, and a shuttle valve 5. To reduce structural volume, improve integration, simplify the piping structure, and enhance operational comfort, in this embodiment, the control valve 1, relief valve 2, combining valve 3, and shuttle valve 5 share a valve body 7. Specifically, the control valve 1, relief valve 2, combining valve 3, check valve 4, and shuttle valve 5 are integrated within the valve body 7. Specifically, a corresponding flow channel is provided within the valve body 7 for each valve body 7, and a valve core is provided within the corresponding flow channel, thereby forming the aforementioned valves. An oil return channel 200 is provided within the valve body 7 to facilitate oil return from each valve.

[0028] The control valve 1 has a first flow channel 11 extending in the left-right direction within the valve body 7. A control valve core 12 is disposed within this first flow channel 11. Port P, port P', and port T are sequentially arranged within this first flow channel 11 from left to right. Port P communicates with the actuator's control oil circuit 100, and port T communicates with the oil return channel 200. A spring 13 is provided at the right end of the first flow channel 11, acting on the control valve core 12. In the initial state of the control valve 1, ports P and P' are connected, but not with port T. As oil enters port P and oil pressure increases, the control valve core 12 shifts rightward, overcoming the force of spring 13. This causes ports P' to communicate with port T, but not with port P.

[0029] Relief valve 2 is connected to control valve 1 and oil return passage 200, respectively. It provides the oil pressure threshold for switching operation of control valve 1. When the oil pressure entering control valve 1 does not exceed its relief pressure, control valve spool 12 of control valve 1 activates, opening ports P and P'. When the oil pressure entering control valve 1 exceeds its relief pressure, control valve spool 12 of control valve 1 activates, opening ports P' and T.

[0030] Relief valve 2 is disposed within an extension of first flow channel 11 and is positioned near spring 13. Relief valve 2 has a set relief pressure threshold. When the pressure of the oil entering control valve 1 exceeds the set relief pressure threshold, relief valve 2 opens, allowing the oil to overcome the elastic force of spring 13 and return to ports P' and T. The oil also returns through relief valve 2. To facilitate adaptation to different truck-mounted crane dual-pump systems, the relief valve 2 in this embodiment features an adjustable set pressure.

[0031] As described in the background technology, the unloaded oil is the working flow channel oil. In order to achieve a limited smoothness in the switching and conduction action of the control valve 1, while limiting the return oil flow of the relief valve 2, minimizing the reduction in the amount of oil in the working flow channel and improving work efficiency, a first damping hole 111 and a second damping hole 112 are provided at both ends of the first flow channel 11. The first damping hole 111 and the second damping hole 112 are respectively connected to the P port through the oil channel; the second damping hole 112 is arranged near the spring 13 and is connected to the inlet of the relief valve 2; the cross-sectional area of ​​the first damping hole 111 is larger than the cross-sectional area of ​​the second damping hole 112. Based on the restriction of the cross-sectional area of ​​the two damping holes, it can ensure that the oil flows smoothly along the normal flow path, avoid sudden changes in flow rate, and effectively limit the amount of oil backflow.

[0032] The merging valve 3 is connected to the small pump 300, the large pump 400, the P' port of the control valve 1, and the oil return channel 200, respectively. The merging valve core of the merging valve 3 opens and closes based on the oil output status of the P' port of the control valve 1. That is, when the control valve 1 is in the P-port and P'-port connected state, the merging valve 3 is open when oil is output to the merging valve 3 through the P' port. When the control valve 1 is in the P'-port and T-port connected state, the P' port no longer outputs oil to the merging valve 3, and the merging valve 3 is closed. When the merging valve 3 is open, the hydraulic oil pumped into the small pump 300 and the large pump 400 merges. When the merging valve 3 is closed, the hydraulic oil pumped into the small pump 300 and the large pump 400 is no longer connected, and the small pump 300 can achieve low-pressure unloading.

[0033] In order to effectively realize the merging of the small pump 300 and the large pump 400, a one-way valve 4 is provided on the oil path connecting the small pump 300 and the merging valve 3.

[0034] The shuttle valve 5 is used to better control the connection between the actuator and the control valve 1. The inlet of the shuttle valve 5 is connected to the oil circuit of the action actuator, and the outlet of the shuttle valve 5 is connected to the P port of the control valve 1 through the oil circuit. The number of shuttle valves 5 is set according to the number of action actuators. The action actuator includes a hoisting mechanism and a telescopic mechanism. A shuttle valve 5 is set to match the hoisting mechanism and the telescopic mechanism. When the action actuators such as the hoisting mechanism and the telescopic mechanism need to perform corresponding actions, the action actuator will output control signal pressure oil to the shuttle valve 5. The control signal pressure oil enters the control valve 1 through the shuttle valve 5, thereby realizing the action of the control valve 1.

[0035] In addition, in order to improve the reliability of the compact flow distribution valve of the truck-mounted crane dual-pump system, a filter 6 is provided on the oil path connecting the shuttle valve 5 and the control valve 1 .

[0036] To ensure smooth operation of the actuators, load-sensing channels 31 are connected between the merging valve 3 and the oil return channel 200, corresponding to the small pump 300 and the large pump 400, respectively. Damping holes 500 are provided on the load-sensing channels 31. The coordination of the load-sensing channels 31 and the damping holes 500 mitigates pressure fluctuations in the load-sensing channels 31, ensuring smoother operation of the various actuators. This also addresses the issue of slow load-sensing pressure release after the actuators complete their operation, further resolving the issue of increased heat generation when the dual pumps are unloaded, thus reducing energy consumption.

[0037] The working process of the compact flow distribution valve based on the truck crane dual-pump system is as follows: when hoisting or telescoping work is required, the truck crane dual-pump system will control the corresponding action actuator to output control signal pressure oil, and the control signal pressure oil passes through the shuttle valve 5 and the filter and enters the control valve 1. In the early stage, the oil pressure entering the control valve 1 is lower than the oil pressure threshold of the overflow valve 2, and the P port and P' port in the corresponding control valve 1 are in the conducting state, that is, the control valve 1 is in the conducting state, and the oil is output to the combining valve 3 through the P' port of the control valve 1, and the oil then flows back to the return oil channel 200 for circulation. The spool of merging valve 3 actuates under the action of the incoming oil, causing it to open. Since the hydraulic oil passages of small pump 300 and large pump 400 are both connected to the main channel within merging valve 3, small pump 300 and large pump 400 operate simultaneously. The hydraulic oil in small pump 300 merges through the open merging valve 3 and flows into the supply channel of large pump 400, which supplies the various actuators. This allows the hydraulic oil from small pump 300 and large pump 400 to merge and act together on the actuators, ensuring rapid activation and accelerated movement, thereby improving operational efficiency. As the control signal pressure oil continues to enter, the oil pressure within control valve 1 continues to rise. When it reaches the combined pressure threshold of relief valve 2 and the elastic force of spring 13, control valve spool 12 actuates, opening ports P' and T. At this point, port P is disconnected, and control valve 1 closes. Oil flows back through port T and relief valve 2 into return oil channel 200. No new oil enters the corresponding merging valve 3, which closes. The small pump 300 and the large pump 400 are disconnected and disconnected. At this point, the small pump 300 can unload at low pressure and no longer operate, thus avoiding heat generation. The hydraulic oil output by the large pump 400 now acts on the actuator, ensuring stable operation at a low speed.

[0038] The compact flow distribution valve based on the dual-pump system of a truck-mounted crane, as described in this invention, can separate and merge the flow of the small pump 300 and the large pump 400. This ensures that the small pump 300 can unload at low pressure under heavy load conditions, preventing excessive and rapid temperature rise. This is more energy-efficient and environmentally friendly, and also avoids the safety hazards caused by engine stalling. This compact flow distribution valve based on the dual-pump system of a truck-mounted crane eliminates the need for additional pressure sensors and solenoid valves, thus preventing electrical failure during operation.

[0039] In the present specification and claims, directional terms such as "front," "back," "up," "down," "left," "right," "side," "top," and "bottom" are used to describe various exemplary structural parts and components of the present invention. However, these terms are used herein for convenience of description only and are based on the exemplary orientations shown in the accompanying drawings. Because the embodiments disclosed herein can be arranged in various orientations, these directional terms are intended for illustrative purposes only and should not be construed as limiting. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A compact flow distribution valve based on a truck-mounted crane dual-pump system, characterized by: include A control valve (1) having a P port, a P' port, and a T port, wherein the P port is connected to a control oil circuit (100) of an actuator, and the T port is connected to an oil return channel (200); The overflow valve (2) is connected to the control valve (1) and the oil return channel (200) respectively; The merging valve (3) is respectively connected to the small pump (300), the large pump (400), the P' port of the control valve (1), and the oil return channel (200). The merging valve core of the merging valve (3) is actuated based on the oil output state of the P' port of the control valve (1) to achieve merging and diversion of the hydraulic oil pumped into the small pump (300) and the large pump (400); A one-way valve (4) is provided on the oil path connecting the small pump (300) and the merging valve (3); When the pressure of the oil flowing into the control valve (1) does not exceed its overflow pressure, the control valve core (12) of the control valve (1) operates to connect the P port and the P' port; when the pressure of the oil flowing into the control valve (1) exceeds its overflow pressure, the control valve core (12) of the control valve (1) operates to connect the P' port and the T port.

2. The compact flow distribution valve based on the truck-mounted crane dual-pump system according to claim 1 is characterized by: It also includes a shuttle valve (5), the inlet of the shuttle valve (5) is connected to the oil circuit of the action actuator, and the outlet of the shuttle valve (5) is connected to the P port of the control valve (1) through the oil circuit.

3. The compact flow distribution valve based on the truck-mounted crane dual-pump system according to claim 2 is characterized by: The action execution mechanism includes a hoisting mechanism and a telescopic mechanism, and a shuttle valve (5) is respectively provided to match the hoisting mechanism and the telescopic mechanism.

4. The compact flow distribution valve based on the truck-mounted crane dual-pump system according to claim 2 is characterized by: A filter screen (6) is provided on the oil path connecting the shuttle valve (5) and the control valve (1).

5. The compact flow distribution valve based on the truck-mounted crane dual-pump system according to any one of claims 2 to 4, characterized in that: The control valve (1), the overflow valve (2), the combining valve (3), the one-way valve (4), and the shuttle valve (5) are integrated into a valve body (7).

6. The compact flow distribution valve based on the truck-mounted crane dual-pump system according to claim 5 is characterized by: A first flow channel (11) extending in the left-right direction is provided in the valve body (7), and the control valve core (12) is provided in the first flow channel (11). The P port, P' port, and T port are provided in sequence from left to right. A spring (13) acting on the control valve core (12) is provided at the right end of the first flow channel (11).

7. The compact flow distribution valve based on the truck-mounted crane dual-pump system according to claim 6 is characterized by: A first damping hole (111) and a second damping hole (112) are provided at both ends of the first flow channel (11), and the first damping hole (111) and the second damping hole (112) are respectively connected to the P port through the oil channel; the second damping hole (112) is arranged close to the spring (13) and is connected to the inlet of the overflow valve (2); The cross-sectional area of ​​the first damping hole (111) is greater than the cross-sectional area of ​​the second damping hole (112).

8. The compact flow distribution valve based on the truck-mounted crane dual-pump system according to any one of claims 1 to 4, characterized in that: A load-sensing flow channel (31) is connected between the merging valve (3) and the oil return channel (200), corresponding to the small pump (300) and the large pump (400), and a damping hole (500) is provided on the load-sensing flow channel (31).

9. The compact flow distribution valve based on a truck-mounted crane dual-pump system according to any one of claims 1 to 4, characterized in that: The relief valve (2) is a relief valve with adjustable set pressure.

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