High-low pressure double pump combined flow multi-way valve

Abstract

The application discloses a high-low pressure double-pump combined flow multi-way valve, which comprises a low-pressure side oil inlet body, a low-pressure side reversing valve piece, a combined flow bridge valve piece, a high-pressure side reversing valve piece and a high-pressure side oil inlet body, wherein the low-pressure side oil inlet body comprises a valve body, a pressure difference guide rod, a check valve, a unloading valve and a safety valve; the valve body is provided with a low-pressure oil inlet channel connected with a low-pressure pump, a combined flow channel section, a main control oil channel section and an oil return channel; when the oil pressure of the combined flow channel section exceeds the protection pressure of the safety valve, the valve core of the safety valve is opened, and the pressure difference guide rod is moved to the position abutting against the valve core; when the pressure of the combined flow channel section is reduced to the set ratio of the protection pressure of the safety valve, the pressure rod guide rod is reset, and then the valve core of the safety valve is reset and closed, and then the valve core of the unloading valve is reset and closed, and the low-pressure side oil inlet body returns to the combined flow state. The application fundamentally solves the system oscillation caused when the load pressure is close to the set pressure of the overflow valve during use.

Description

TECHNICAL FIELD

[0001] The present application relates to a high-low pressure double pump combined flow multi-way valve. BACKGROUND

[0002] Many actions in engineering machinery not only need independent work but also need collaborative work. If the flow demand of collaborative work is to be met when using a single pump system, the flow of the pump needs to be very large, and the flow needs to be relatively small when working alone. The excess flow does not do work, and energy is wasted. Therefore, double pump systems are often used in engineering machinery.

[0003] In a double pump system, because the requirements of various actions for flow and pressure are different, in order to save energy and cost, a combination of a high-pressure pump and a low-pressure pump is basically used. When complex actions and large flow are needed, double pump combined flow is adopted. When the power is close to the maximum input power of the engine or the load pressure is higher than the rated pressure of the low-pressure pump, the low-pressure pump needs to be unloaded to protect the engine and the low-pressure pump.

[0004] The prior art uses a low-pressure pump to set a fixed pressure overflow valve for control. Although it can protect the engine and the low-pressure pump, when unloading, it is unloaded at the set pressure of the overflow valve. At this time, although the flow of the low-pressure pump does not participate in actual work, the unloading is high-pressure unloading, and the low-pressure pump is consuming high power, and all the energy is wasted in heat, generating heat in the hydraulic system, thereby causing high temperature in the system.

[0005] In the process of implementing the present application, the present inventors have found that the set value of the overflow valve is a fixed value. When the load pressure reaches the set value, the overflow will be opened, and when the load pressure is lower than the set value, it will be closed. Due to the uncertainty of the load in actual system work, the load pressure will often be close to the set pressure of the low-pressure pump protection overflow valve. At this time, the system will generate system oscillation because of the frequent opening-closing-opening of the low-pressure pump protection overflow valve, which brings very unstable factors to the whole machine, and is prone to cause production safety accidents. SUMMARY

[0006] The purpose of the present application is a high-low pressure double pump combined flow multi-way valve to meet the requirements of high-low pressure double pump combined flow and automatic low-pressure unloading of the low-pressure pump when high pressure.

[0007] To this end, the application provides a high-low pressure double pump combined flow multi-way valve, comprising a low pressure side oil inlet body, a low pressure side reversing valve piece, a combined flow bridge valve piece, a high pressure side reversing valve piece and a high pressure side oil inlet body, the low pressure side oil inlet body comprising a valve body, a pressure difference guide rod, a check valve, a unloading valve and a safety valve, the valve body having a low pressure oil inlet channel connected with a low pressure pump, a combined flow oil channel segment, a main control oil channel segment and a return oil channel, the valve body further comprising a supply oil channel vertically communicated with the low pressure oil inlet channel and an unloading oil channel laterally communicated with the low pressure oil inlet channel, the supply oil channel being provided with a check valve, the supply oil channel being communicated with the combined flow oil channel segment when the check valve core is opened, the unloading oil channel being provided with an unloading valve, the unloading oil channel being communicated with the return oil channel when the unloading valve core is opened, the valve body further comprising a safety oil channel communicated with a spring cavity of the unloading valve and a guide rod cavity, one end of the guide rod cavity being communicated with the safety oil channel and the other end being communicated with the combined flow oil channel, the unloading valve core having a throttling hole communicated with the spring cavity and the unloading oil channel, the pressure difference guide rod being movably arranged in the guide rod cavity and being able to top the safety valve core under the bias of the high pressure side, wherein when the oil pressure of the combined flow oil channel segment exceeds the protection pressure of the safety valve, the safety valve core is opened and the pressure difference guide rod is moved to a position abutting against the valve core, and when the pressure of the combined flow oil channel segment is reduced to a set ratio of the protection pressure of the safety valve, the pressure rod guide rod is reset, and then the safety valve core is reset and closed, and then the unloading valve core is reset and closed, and the low pressure side oil inlet body returns to the combined flow state.

[0008] The multi-way valve can realize double pump combined flow, can also work independently with a single pump, and can realize unloading of the low pressure pump when the pressure reaches a certain value according to the system power requirement or the highest pressure protection requirement of the low pressure pump during the combined flow process, and the unloading is performed in a low pressure mode, at this time, the low pressure pump basically does not work any more, system power is not wasted, energy is saved, and the combined flow can be realized again only when the load pressure is reduced to a certain percentage of the protection set pressure after the low pressure unloading, that is, the opening and closing set pressures of the low pressure unloading valve are different and have a certain proportional relationship, so as to fundamentally solve the system oscillation caused when the load pressure is close to the set pressure of the overflow valve during use, and avoid various safety accidents caused by system oscillation.

[0009] In addition to the purposes, features and advantages described above, the application has other purposes, features and advantages. The application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0010] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the application, explain the application. The drawings are as follows:

[0011] Figure 1 is a structural schematic view of the high-low pressure double pump combined flow multi-way valve provided by the embodiment of the application.

[0012] Figure 2 is a right view of Figure 1 ;

[0013] Figure 3 is a schematic view of the inner wall surface oil passage distribution of the low-pressure side oil inlet body provided by the embodiment of the present application, i.e. the A-A view in Figure 1 ;

[0014] Figure 4 shows the cross-sectional structure of the low-pressure unloading assembly of the low-pressure side oil inlet body provided by the embodiment of the present application, i.e. the B-B cross-sectional view in Figure 1 ;

[0015] Figure 5 shows the cross-sectional structure of the tee pressure compensator of the low-pressure side oil inlet body provided by the embodiment of the present application, i.e. the C-C cross-sectional view in Figure 1 ;

[0016] Figure 6 shows the cross-sectional structure of the over-bridge combined valve disc provided by the embodiment of the present application, i.e. the D-D cross-sectional view in Figure 1 ;

[0017] Figure 7 is a hydraulic principle diagram of the high-low pressure double-pump combined multi-way valve provided by the embodiment of the present application;

[0018] Figure 8 is a partial enlarged view of Figure 7 , wherein the low-pressure side oil inlet body part is shown;

[0019] Figure 9 is a partial enlarged view of Figure 7 , wherein the over-bridge combined valve disc part is shown;

[0020] Figure 10 is a partial enlarged view of Figure 7 , wherein the high-pressure side oil inlet body part is shown. DETAILED DESCRIPTION

[0021] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0022] With reference to Figures 1 to 10 , the multi-way reversing valve comprises a low-pressure side oil inlet body 1, a low-pressure side reversing valve disc, a combined over-bridge valve disc 3, a high-pressure side reversing valve disc, and a high-pressure side oil inlet body 7.

[0023] In an embodiment, the multi-way reversing valve is a special valve for a truck crane, the low-pressure side reversing valve disc is set as a rotary valve disc 2 to control the rotary motor of the truck crane; the high-pressure side reversing valve disc is set as a plurality of connections, respectively, a telescopic valve disc 4, an amplitude valve disc 5, and a winch valve disc 6. Among them, the telescopic valve disc 4 controls the telescopic cylinder of the truck crane, the amplitude valve disc 5 controls the amplitude cylinder of the truck crane, and the winch valve disc 6 controls the winch motor of the truck crane.

[0024] The low-pressure side oil inlet body 1 includes a valve body, a differential pressure guide rod 21, a one-way valve 22, an unloading valve 10, a safety valve 20, and a three-way pressure compensator 24 arranged on the valve body. Among them, the differential pressure guide rod 21, the unloading valve 10, and the safety valve 20 are main components of the low-pressure unloading assembly 8.

[0025] The valve body has a top surface oil inlet port P2, a top surface oil return port T2, a low-pressure oil inlet channel 11 communicating with the top surface oil inlet port, an oil return channel communicating with the top surface oil return port, an oil supply channel 13 vertically extending at the end of the low-pressure oil inlet channel and an unloading oil channel 12 extending laterally, a confluence oil channel section p1, and a main control oil channel section s1.

[0026] The oil supply channel 13 is provided with a one-way valve 22 to realize selective conduction with the confluence oil channel section p1, wherein when the spool of the one-way valve moves downward, the oil supply channel is connected to the confluence oil channel section to supply oil to the confluence oil channel.

[0027] The unloading oil channel 12 is provided with an unloading valve 10 to realize selective conduction with the oil return channel, wherein when the spool 16 of the unloading valve is opened, oil is returned to the oil return channel, and the spool 16 of the unloading valve has a throttle hole 17, through which the oil in the unloading oil channel is introduced into the spring cavity 18 of the unloading valve.

[0028] The spring cavity 18 is connected with the vertically extending safety oil channel 14, and the valve body is also provided with a guide rod cavity 15, one end of which is connected with the confluence oil channel section p1, and the other end is connected with the safety oil channel 14. The differential pressure guide rod 21 is arranged in the guide rod cavity 15, and when the differential pressure guide rod 21 moves to the left, it can open the valve core 19 of the safety valve to make the safety oil channel return oil to the oil return channel.

[0029] The spool 23 of the one-way valve 22 has high-pressure pump oil and low-pressure pump oil at both ends. The differential pressure guide rod is a control guide rod with an area difference, and the two ends of the guide rod are connected with high-pressure pump oil and low-pressure pump oil, respectively.

[0030] When the pressure difference guide rod 21 is in balance at the time of merging. When the pressure reaches the low pressure pump protection pressure, the safety valve 20 opens, at this time the pressure difference guide rod 21 both ends lose balance, the high pressure pump side of the pressure difference guide rod 21 is pressed, and the pressure difference guide rod 21 is pressed to the valve core of the safety valve 20, keeping the safety valve open, the unloading valve 10 valve core both sides lose pressure balance, so that the unloading valve 10 valve core is fully open, at this time the low pressure pump is unloaded from the unloading valve 10 without load, the low pressure pump no longer works, because of the area difference of the guide rod, the high pressure pump side pressure is reduced to the protection pressure x area ratio (safety valve core pressure area: guide rod high pressure pump side pressure area, for example, the design value is 60%, which can be set according to the system requirements), that is, when the high pressure pump pressure is reduced to the design value of the safety valve protection pressure, the valve core of the safety valve will be closed, and the low pressure pump can participate in the merging work again, so as to avoid the system oscillation caused by the same opening and closing value of the ordinary overflow valve when the load pressure is close to the set pressure.

[0031] The rotary valve 2 is composed of a main reversing valve 27 and a two-way pressure compensator 28. The oil in the two-way pressure compensator comes from the main reversing valve, which acts together when the main reversing valve changes direction, supplies oil to the main control oil way, and supplies flow to the working oil ports A4 and B4 as needed. The main reversing valve is a three-position seven-way manual reversing valve with oil return throttling function. Its reversing hydraulic principle is shown in Figure 9 The A port oil way and the B port oil way of the rotary valve 2 each have load limitation, which is realized by overflow valves 29 and 30.

[0032] The merging over-bridge valve piece includes a two-position four-way valve 25, which includes a normally closed position and a disconnected position. When the normally closed position, the control oil way and the merging oil way are respectively connected. When the rotary valve 2 changes direction, the two-position four-way valve 25 is controlled to switch to the disconnected position, and the merging oil way and the main control oil way on both sides of the merging over-bridge valve piece are disconnected. The control mode is as follows: the A port oil way and the B port oil way of the rotary valve lead the control oil to the shuttle valve 26, and the output port of the shuttle valve is connected to the hydraulic control end of the two-position four-way valve 25. When there is a pressure difference between the A port oil way and the B port oil way (caused by the reversing action of the main valve), the shuttle valve acts to provide control oil to the two-position four-way valve, so that the two-position four-way valve switches to the disconnected position.

[0033] The telescopic valve piece has the same structure as the rotary valve piece, except that its corresponding A port oil way has load limitation, which is realized by connecting an overflow valve, while the B port oil way is not limited in load. The structure of the variable amplitude valve piece is the same as that of the rotary valve piece, except that its corresponding B port oil way has load limitation, which is realized by connecting an overflow valve. The winch valve piece includes a main reversing valve 31 and a two-way pressure compensator 32, which has the same structure as the rotary valve piece, except that its corresponding B port oil way has load limitation, which is realized by connecting an overflow valve 33.

[0034] The high pressure oil inlet body comprises a valve body, a three-way pressure compensator 35, and an overflow valve 34, wherein the valve body has a high pressure oil inlet port P1, a high pressure oil channel connected with the high pressure oil inlet port, a return oil port T2, a return oil channel connected with the return oil port T2, a confluence flow channel section, and a high pressure main control oil channel section. The control oil of the three-way pressure compensator 35 is taken from the main control oil channel section, and the main control oil channel section is supplied with oil when the low pressure side reversing valve piece or the high pressure side reversing valve piece is reversed. The overflow valve is arranged on the main control oil channel section, and the oil in the main control oil channel section also flows into the return oil channel through a filter and a throttle valve.

[0035] The reversing multi-way valve is provided with a plurality of pressure measuring ports MT, MP1, MP2, MLS1 and K, and each pressure measuring port is provided with a check valve for opening the pressure measuring port during pressure measurement and closing the pressure measuring port during non-pressure measurement.

[0036] The parameters of each oil port of the double-pump confluence multi-way valve are set as shown in the following table:

[0037] The parameters of each oil port

[0038]

[0039] The action of the double-pump confluence multi-way valve is as follows: when the rotary valve piece is actuated, the confluence flow channel on the high pressure side is disconnected through the confluence bridge valve piece, and at this time, the low pressure pump supplies oil alone. When the hoist valve piece, the luffing valve piece or the telescopic valve piece is actuated, the low pressure pump supplies oil to the actuated valve piece in confluence, and when the pressure is higher than the protection pressure of the low pressure pump, the low pressure pump is unloaded at low pressure, and the confluence is automatically disconnected. When the pressure of the high pressure pump is reduced to the design value of the protection pressure of the safety valve, the safety valve is closed, and the low pressure pump can participate in the confluence work again.

[0040] The above description is only an embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A high- and low-pressure dual-pump confluence multi-way valve, characterized in that, This includes the low-pressure side oil inlet body, the low-pressure side reversing valve plate, the confluence bridge valve plate, the high-pressure side reversing valve plate, and the high-pressure side oil inlet body. The low-pressure side oil inlet body includes a valve body, a differential pressure guide rod, a check valve, an unloading valve, and a safety valve. The valve body has a low-pressure oil inlet, a low-pressure oil inlet passage connected to the low-pressure oil inlet, a confluence oil passage segment, a main control oil passage segment, a return oil port T1, and a return oil passage connected to the return oil port. The valve body also includes an oil supply passage vertically connected to the low-pressure oil inlet passage and an unloading oil passage laterally connected to the low-pressure oil inlet passage. The oil supply passage is equipped with a check valve, which supplies oil to the confluence oil passage when the check valve spool is open. The unloading oil passage is equipped with an unloading valve, which returns oil to the return oil passage when the unloading valve spool is open. The valve body also includes a safety oil passage communicating with the spring cavity of the unloading valve, and a guide rod cavity. One end of the guide rod cavity is connected to the safety oil passage, and the other end is connected to the confluence oil passage. The valve core of the unloading valve has a throttling orifice connecting the spring cavity and the unloading oil passage. The differential pressure guide rod is movably disposed in the guide rod cavity and can be biased by the high-pressure side to open the valve core of the safety valve. When the oil pressure in the confluence oil passage section exceeds the protection pressure of the safety valve, the valve core of the safety valve opens while the differential pressure guide moves to a position abutting against the valve core. When the pressure in the confluence oil passage section decreases to the set ratio of the protection pressure of the safety valve, the differential pressure guide resets, and then the valve core of the safety valve resets and closes, and then the valve core of the unloading valve resets and closes, and the low-pressure side oil inlet body returns to the confluence state.

2. The high and low pressure dual-pump confluence multi-way valve according to claim 1, characterized in that, The low-pressure side oil inlet body is also equipped with a three-way pressure compensator and a main control oil passage section. The control oil of the three-way pressure compensator is taken from the main control oil passage section, which is supplied with oil by the low-pressure side reversing valve or the high-pressure side reversing valve during the reversing action.

3. The high and low pressure dual-pump confluence multi-way valve according to claim 1, characterized in that, The low-pressure side reversing valve plate includes a main reversing valve, a two-way pressure compensator, a confluence oil passage section, and a main control oil passage section. The two-way pressure compensator introduces the oil in the confluence oil passage section into the main control oil passage section when the main reversing valve reverses.

4. The high and low pressure dual-pump confluence multi-way valve according to claim 1, characterized in that, The merging bridge valve includes a two-position four-way valve, which has a normally closed position and an open position. In the normally closed position, the merging oil circuit and the main control oil circuit remain connected. In the open position, the merging oil circuit and the main control oil circuit are disconnected. The control oil for the two-position four-way valve during its reversing action is provided by a shuttle valve. The two input terminals of the shuttle valve are respectively connected to the A-port channel and the B-port channel of the low-pressure side reversing valve, and the output terminal of the shuttle valve is connected to the control terminal of the two-position four-way valve.

5. The high and low pressure dual-pump confluence multi-way valve according to claim 1, characterized in that, The high-pressure side reversing valve plate includes a main reversing valve, a two-way pressure compensator, a confluence oil passage section, and a main control oil passage section. The two-way pressure compensator introduces the oil in the confluence oil passage section into the main control oil passage section when the main reversing valve reverses.

6. The high and low pressure dual-pump confluence multi-way valve according to claim 1, characterized in that, The high-pressure side oil inlet body has a high-pressure oil inlet, a high-pressure oil inlet channel connected to the high-pressure oil inlet, a return oil inlet T2, a return oil channel connected to the return oil inlet, a confluence oil channel section, and a main control oil channel section. The high-pressure side oil inlet body is also equipped with a three-way pressure compensator. The control oil of the three-way pressure compensator is taken from the main control oil channel section, which is supplied with oil by the low-pressure side reversing valve or the high-pressure side reversing valve during the reversing action.

7. The high and low pressure dual-pump confluence multi-way valve according to claim 1, characterized in that, The main control oil passage section is equipped with an overflow valve, a throttle valve, and a filter.

8. The high and low pressure dual-pump confluence multi-way valve according to claim 1, characterized in that, The high and low pressure dual-pump confluence multi-way valve is a truck crane multi-way valve. The low-pressure side reversing valve plate in the truck crane multi-way valve is a rotary valve plate, and the high-pressure side reversing valve plate includes a telescopic valve plate, a luffing valve plate, and a winch valve plate.

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