阅读说明：本技术 一种卸荷阀及其装载机液压多泵合流系统 (Unloading valve and loader hydraulic multi-pump confluence system thereof ) 是由 闫云乔 徐奉 黄学强 王晓燕 郄严静 张祥 于 2021-06-29 设计创作，主要内容包括：本发明公开一种卸荷阀及其装载机液压多泵合流系统,包括：阀体,该阀体上具有进油口,与该进油口连通的第一油道、第二油道,第三油道,主阀腔。复位式导阀连接在第一油道中,且复位式导阀的进油端靠近进油口,第一单向阀连接在该进油端上。第三油道一端与该出油端所在侧的第一油道连通,第三油道另一端、第二油道另一端分别与主阀腔的两端连通。复位式主阀由堵头密封在主阀腔中。复位式主阀的靠近第三油道的一端具有与出油口连通的节流孔,该端堵头具有连通主阀腔内外部的外控口,外控口中连接只许从外部进液的第二单向阀。该系统能够快速、方便地实现装载机在上述复合工况和普通工况的良好工作及快速切换,有效提高了装载机的工作效率。(The invention discloses an unloading valve and a loader hydraulic multi-pump confluence system thereof, comprising: the valve body is provided with an oil inlet, a first oil duct, a second oil duct, a third oil duct and a main valve cavity, wherein the first oil duct, the second oil duct, the third oil duct and the main valve cavity are communicated with the oil inlet. The reset type pilot valve is connected in the first oil duct, the oil inlet end of the reset type pilot valve is close to the oil inlet, and the first one-way valve is connected to the oil inlet end. One end of the third oil duct is communicated with the first oil duct on the side where the oil outlet end is located, and the other end of the third oil duct and the other end of the second oil duct are respectively communicated with two ends of the main valve cavity. The reset main valve is sealed in the main valve cavity by a plug. And one end of the reset main valve close to the third oil duct is provided with an orifice communicated with the oil outlet, the end plug is provided with an external control port communicated with the inside and the outside of the main valve cavity, and a second one-way valve only allowing liquid to enter from the outside is connected in the external control port. The system can quickly and conveniently realize good work and quick switching of the loader under the composite working condition and the common working condition, and effectively improves the working efficiency of the loader.)

1. An unloader valve, wherein the unloader valve comprises:

the valve body is provided with an oil inlet, a first oil duct, a second oil duct, a third oil duct and a main valve cavity, wherein the first oil duct, the second oil duct, the third oil duct and the main valve cavity are communicated with the oil inlet;

the resetting type pilot valve is connected in the first oil duct, the oil inlet end of the resetting type pilot valve is close to the oil inlet, and the first one-way valve is hermetically connected to the oil inlet end;

one end of the third oil duct is communicated with the first oil duct on the side where the oil outlet end of the reset type pilot valve is located, and the other end of the third oil duct and the other end of the second oil duct are respectively communicated with two ends of the main valve cavity;

a return main valve sealed in the main valve chamber by a plug, the return main valve being communicated with the main valve chamber when pressed to the side of the second oil passage; one end of the reset main valve close to the third oil duct is provided with a throttling hole communicated with an oil outlet on the valve body, and a middle plug at the end is provided with an external control port communicated with the inside and the outside of the cavity of the main valve;

and the second one-way valve is connected in the external control port, and only liquid is allowed to enter from the outside of the external control port.

2. The unloader valve according to claim 1, wherein the first oil passage is horizontally disposed, a left end thereof communicates with the oil inlet, and the reset pilot valve has a mechanism capable of reciprocating in the first oil passage;

preferably, the reset pilot valve includes a first valve stem, a valve spool, and a first reset member, wherein: the first valve rod is internally provided with a channel communicated with first oil ducts on two sides of the first valve rod, the valve core is movably and hermetically arranged in the channel, the left end of the first resetting piece is connected with the valve core, and the right end of the first resetting piece is fixed in the first oil ducts;

preferably, the first restoring member is an elastic telescopic member, and more preferably a spring.

3. The unloading valve according to claim 2, wherein a right port of the first oil passage is communicated with the outside of the valve body, an end enclosure is detachably connected to the right port, and the right end of the first resetting member is connected with the end enclosure.

4. The unloader valve according to claim 1, wherein the main valve chamber is horizontally disposed with a left side communicating with a lower end of a second oil passage and a right side communicating with a lower end of the second oil passage, and a right end of the main valve chamber is provided with the oil outlet communicating an orifice hole with an outside of the valve body.

5. The unloader valve of any one of claims 1 to 4, wherein the reset main valve comprises a second valve stem, a second reset member, wherein: the left end of the second reset piece is connected with a plug connected to the left port of the main valve cavity, and the right end of the second reset piece is connected with the left end of the second valve rod.

6. The unloader valve according to claim 5, wherein the diameter of both ends of the second stem is larger than the middle diameter, and when the second stem is in an uncompressed state, the left sidewall of the second stem contacts the inner wall of the main valve chamber to close the lower end of the second oil passage, and the right sidewall of the second stem always contacts the inner wall of the main valve chamber.

7. The unloading valve according to claim 6, wherein a counter bore is formed in the right end face of the second valve rod, the throttle hole is formed in the right side wall of the second valve rod, and two ends of the throttle hole are respectively communicated with the counter bore and the oil outlet; preferably, the second restoring member is an elastic telescopic member, and more preferably a spring.

8. A loader hydraulic multi-pump flow combining system, wherein the system comprises: flow valve, a steering system, unloading valve, operating system, switching-over valve, guide's pump and guide control system, wherein:

an unloader valve as claimed in any one of claims 1 to 7;

the oil inlet of the flow valve is communicated with an oil tank through a steering pump, the oil outlet of the flow valve is simultaneously communicated with the oil inlets of the steering system and the unloading valve, and the oil outlet of the unloading valve is connected with the oil outlet of the working pump;

the working system is connected with a working pump, and the working pump is communicated with an oil tank;

the oil outlet of the pilot pump is connected with the external control port of the unloading valve through a reversing valve;

an oil inlet and an oil outlet of the pilot pump are respectively communicated with the oil tank and the pilot control system;

the pilot control system is communicated with the working system.

9. The loader hydraulic multi-pump confluence system of claim 8, wherein the reversing valve comprises any one of a solenoid reversing valve, an electro-hydraulic reversing valve, a motorized reversing valve, and a manual reversing valve.

10. The loader hydraulic multi-pump confluence system of claim 8 or 9, further comprising an overflow valve communicating the pilot operated system with a tank.

Technical Field

The invention relates to the technical field of loaders, in particular to an unloading valve and a hydraulic multi-pump confluence system of a loader.

Background

The information disclosed in this background of the invention is only for enhancement of understanding of the general background of the invention and is not necessarily to be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

When the hydraulic multi-pump confluence system of the loader is not provided with the equivalent unloading valve, the system pressure of a working device usually exceeds the set pressure of a safety valve of the working system during the shoveling operation, so that the system usually works in an overflow state to cause energy loss, and the hydraulic system has high power consumption and high heat generation amount. Therefore, when the confluence system is added with an equivalent unloading valve and then carries out shoveling operation, specifically, referring to the attached drawings 1 to 3 of the specification, which are structural schematic diagrams of the unloading valve and a loader hydraulic multi-pump confluence system of an embodiment in the prior art, when the system works, when the pressure of a working system reaches the set pressure of the equivalent unloading valve, a small part of hydraulic oil in a flow valve enters a first oil passage a through an oil inlet P1 of the equivalent unloading valve, a reset pilot valve is opened under the action of oil pressure, the hydraulic oil further passes through a third oil passage c and then passes through a throttling port j to form differential pressure, the hydraulic oil enters an oil outlet T to generate pressure drop, meanwhile, the reset main valve is opened by the hydraulic oil, and the hydraulic oil from the flow valve directly flows out from the oil outlet T after passing through a second oil passage b from the oil inlet P1, so that the hydraulic oil of a steering system confluence working system device can realize low-pressure unloading, the saved power of the steering hydraulic system can be transferred to a driving system in the working system, so that the whole machine driving force of the loader is improved, and the purposes of saving energy and improving the working efficiency are achieved. Under the working condition of large arm lifting (simply referred to as 'lifting'), because the maximum oil pressure value of the working system is lower than the set pressure of the equivalent unloading valve pressure, the unloading valve does not work at the moment, hydraulic oil in the steering system is converged to a working system device, and the minimum lifting time is ensured to meet the standard requirement.

Disclosure of Invention

However, the present invention further finds: under the complex composite action working conditions of lifting, walking and the like, the composite action hydraulic loading system is characterized in that large lifting force and driving force are needed, but the requirement on the lifting speed is not high, but because the maximum oil pressure of a steering system is lower than the set pressure of an equivalent unloading valve, under the composite working conditions, the unloading valve and the loading machine hydraulic multi-pump confluence system shown in the specifications of the attached drawings 1 to 3 can not enable redundant hydraulic oil in a flow valve to realize low-pressure unloading, so that the problems that the whole hydraulic system is large in power consumption and small in driving force are caused, the composite action of lifting and walking can not be realized, only the lifting and walking can be carried out firstly during operation, and the working efficiency of the loading machine is relatively influenced.

Aiming at the problems, the invention provides the unloading valve and the hydraulic multi-pump confluence system of the loader thereof, which can quickly and conveniently realize the good work and the quick switching of the loader under the composite working condition and the common working condition, and effectively improve the working efficiency of the loader. In order to achieve the purpose, the technical scheme of the invention is as follows.

In a first aspect of the invention, an unloader valve is disclosed, comprising: valve body, reset formula pilot valve, first check valve, reset formula main valve, end cap and second check valve, wherein: the valve body is provided with an oil inlet, a first oil duct, a second oil duct, a third oil duct and a main valve cavity, wherein the first oil duct, the second oil duct, the third oil duct and the main valve cavity are communicated with the oil inlet. The reset type pilot valve is connected in the first oil duct, the oil inlet end of the reset type pilot valve is close to the oil inlet, and the first one-way valve is connected to the oil inlet end. One end of the third oil duct is communicated with the first oil duct on the side where the oil outlet end is located, and the other end of the third oil duct and the other end of the second oil duct are respectively communicated with two ends of the main valve cavity. The reset main valve is sealed in the main valve cavity by a plug, and the reset main valve is communicated with the main valve cavity when being pressed to the side of the second oil duct. And one end of the reset main valve, which is close to the third oil duct, is provided with an orifice communicated with the oil outlet, a plug at the end is provided with an external control port communicated with the inside and the outside of the cavity of the main valve, and the external control port is connected with a second one-way valve only allowing liquid to enter from the outside.

Furthermore, the first oil duct is horizontally arranged, the left end of the first oil duct is communicated with the oil inlet, and the reset type pilot valve is provided with a mechanism capable of reciprocating in the first oil duct and controlling the connection and disconnection between the first oil duct and the third oil duct.

Further, the reset pilot valve includes a first valve stem, a valve core and a first reset piece, wherein: the first valve rod is internally provided with a channel communicated with first oil ducts on two sides of the first valve rod, the valve core is movably and hermetically arranged in the channel, the left end of the first resetting piece is connected with the valve core, and the right end of the first resetting piece is fixed in the first oil ducts.

Furthermore, the right port of the first oil duct is communicated with the outside of the valve body, a seal head is detachably connected to the right port, and the right end of the first reset piece is connected with the seal head so as to facilitate the installation and the disassembly of each part of the reset type pilot valve.

Furthermore, the main valve cavity is horizontally arranged, the left side of the main valve cavity is communicated with the lower end of a second oil duct, the right side of the main valve cavity is communicated with the lower end of the second oil duct, and the right end of the main valve cavity is provided with the oil outlet communicated with the throttling hole and the outside of the valve body, so that the oil duct in the valve body can be communicated with the outside of the valve body, and smooth unloading and oil outlet are ensured.

Further, the reset main valve includes second valve rod, the second piece that resets, wherein: the left end of the second reset piece is connected with a plug connected to the left port of the main valve cavity, and the right end of the second reset piece is connected with the left end of the second valve rod.

Furthermore, the diameters of the two ends of the second valve rod are larger than the middle diameter, when the second valve rod is in an uncompressed state, the left side wall of the second valve rod is in contact with the inner wall of the main valve cavity to close the lower end of the second oil duct, and the right side wall of the second valve rod is always in contact with the inner wall of the main valve cavity to prevent oil leakage, so that the second valve rod cannot be compressed leftwards, and the second oil duct is communicated with the main valve cavity.

Furthermore, a counter bore is formed in the end face of the right end of the second valve rod, the throttle hole is formed in the side wall of the right portion of the second valve rod, and two ends of the throttle hole are communicated with the counter bore and the oil outlet respectively.

Further, the first reset piece and the second reset piece are both springs, and the springs are used as reset components to enable the reset pilot valve and the reset main valve to be switched on and off along with the change of oil pressure.

In a second aspect of the present invention, a loader hydraulic multi-pump confluence system is disclosed, comprising: flow valve, a steering system, unloading valve, operating system, switching-over valve, guide's pump and guide control system, wherein: the oil inlet of the flow valve is communicated with the oil tank through a steering pump, the oil outlet of the flow valve is simultaneously communicated with the oil inlets of the steering system and the unloading valve, and the oil outlet of the unloading valve is connected with the oil outlet of the working pump. The working system is connected with a working pump, and the working pump is communicated with an oil tank; the oil outlet of the pilot pump is connected with the outer control port of the unloading valve through a reversing valve, the oil inlet and the oil outlet of the pilot pump are respectively communicated with the oil tank and the pilot control system, and the pilot control system is communicated with the working system.

Furthermore, the reversing valve comprises any one of an electromagnetic reversing valve, an electro-hydraulic reversing valve, a motorized reversing valve, a manual reversing valve and the like, and the reversing valve mainly has the function of realizing the cooperative work with a pilot pump through the on-off of the reversing valve, and further starts the unloading valve to carry out low-pressure unloading under the condition that the oil pressure of a steering system is lower than that of the unloading valve.

Furthermore, the hydraulic control system also comprises an overflow valve for communicating the pilot control system and the oil tank, so that the influence on the work caused by the overlarge oil pressure of the pilot control system is prevented.

Compared with the prior art, the invention has the following beneficial effects:

the unloading valve is provided with an external control opening on a plug, and a second one-way valve which only allows the external liquid of the valve body to enter is arranged in the external control opening. On the basis, after the unloading valve and the reversing valve are combined in a hydraulic multi-pump confluence system of a loader: when the loader is under the composite working condition of lifting and walking, the electromagnetic reversing valve is electrified and opened, partial pressure oil in the pilot pump enters the main valve cavity through the reversing valve, the second valve rod moves left under the pressure of the pressure oil and keeps the state under the pressure of the hydraulic oil, the second oil duct is communicated with the main valve cavity, the hydraulic oil from the first oil duct is directly discharged from the oil outlet after passing through the second oil duct and the main valve cavity, and the oil outlet is connected with the oil outlet pipeline of the working pump to the working system, so that redundant flow in the steering pump is merged into the oil outlet of the working pump, and the driving force of the working system is improved. After the working condition is finished, the reversing valve is closed, the quick switching between the two working conditions is realized, the composite action state of lifting and walking can be met, the normal working condition (no special requirement on driving force) can be met, and the working efficiency is improved. Therefore, the loader can adapt to the requirements of common working conditions and composite working conditions, the problem that the original system cannot work in a composite mode under the composite working conditions is solved, and the working efficiency is effectively improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

Fig. 1 is a schematic structural diagram of an unloading valve and a pilot valve thereof in a closed state in the prior art.

Fig. 2 is a schematic structural diagram of an unloading valve and a pilot valve thereof in an open state in the prior art.

Fig. 3 is a schematic structural diagram of a loader hydraulic multi-pump confluence system in the prior art.

Fig. 4 is a schematic structural diagram of an unloading valve and a pilot valve thereof in a closed state.

Fig. 5 is a schematic structural diagram of an unloading valve and its pilot valve in an open state according to the present invention.

Fig. 6 is a schematic structural diagram of a hydraulic multi-pump confluence system of a loader according to the present invention.

The scores in the above figures represent:

1-valve body, 2-reset type pilot valve, 2.1-first valve rod, 2.2-valve core,

2.3-a first reset piece, 2.4-a channel, 2.5-a sealing head, 3-a first one-way valve,

4-reset type main valve, 4.1-second valve rod, 4.2-second reset piece, 4.3-counter bore,

5-plug, 6-second one-way valve, P1-oil inlet, a-first oil channel,

b-a second oil duct, c-a third oil duct, d-a main valve cavity, a T-oil outlet,

j-orifice, k-external control port, 7-flow valve, 8-steering system,

9-unloading valve, 10-working system, 11-reversing valve, 12-pilot pump,

13-pilot control system, 14-steering pump, 15-oil tank, 16-working pump,

17-relief valve.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

For convenience of description, the words "up", "down", "left" and "right" in the present invention, if any, merely indicate that the directions of movement are consistent with those of the drawings, and do not limit the structure, but merely facilitate the description of the invention and simplify the description, rather than indicate or imply that the referenced device or element needs to have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention. The description will be further described with reference to the drawings and specific examples.

As described above, under complex composite operation conditions such as lifting and walking, the unloading valve and the hydraulic multi-pump confluence system of the loader shown in fig. 1 to 3 cannot unload the redundant hydraulic oil in the flow valve at low pressure, so that the composite operation of lifting while walking cannot be realized, and only the loader can be lifted first and then walks during operation, which affects the working efficiency of the loader. Therefore, the invention provides an unloading valve and a hydraulic multi-pump confluence system of a loader thereof, which are further described with reference to the attached drawings and the specific implementation mode of the specification.

First, referring to fig. 4 and 5, a novel unloading valve proposed by the present invention is illustrated, which is an assembly including a valve body 1, a reset pilot valve 2, a first check valve 3, a reset main valve 4, a plug 5, a second check valve 6, and the like. Through further optimizing and improving the structure of the unloading valve in the figures 1 and 2, the hydraulic multi-pump confluence system of the loader formed by the novel unloading valve effectively overcomes the technical problems, so that the loader has the capacity of executing the compound action of lifting and walking, and the working efficiency of the loader is effectively improved.

Based on the above problems to be solved and the objects to be achieved, the above new unloading valve will now be described in detail by the following specific embodiments.

With continued reference to fig. 4 and 5, an oil inlet P1 is formed in the valve body 1, and the valve body 1 has a first oil passage a, a second oil passage b, a third oil passage c, and a main valve cavity d therein, wherein: in order to effectively utilize the space in the valve body 1 and reasonably arrange all the components in the valve body 1 to enable the components to work cooperatively, the oil inlet P1 is arranged at the upper right part of the valve body 1, the first oil passage a is horizontally arranged, the left port of the first oil passage a is communicated with the oil inlet P1, and the right port of the first oil passage a is communicated with the outside of the valve body 1. In addition, it should be understood that the first oil passage a may also be designed to penetrate through the valve body 1, and then the first oil passage a is blocked by a blocking component detachably connected in the port of the first oil passage a, so as to avoid oil leakage. That is, the arrangement form of the first oil passage a in the valve body 1 is not limited to that exemplified in the present embodiment, and a skilled person can design and adjust the arrangement according to actual needs, and similarly, the specific position arrangement of the second oil passage b, the third oil passage c, the main valve chamber d, and the like can also be designed and adjusted according to actual needs.

Further, the reset type pilot valve 2 can reciprocate in the first oil passage a to control the connection and disconnection between the first oil passage a and the third oil passage c. Specifically, the method comprises the following steps: the reset type pilot valve 2 comprises a first valve rod 2.1, a valve core 2.2 and a first reset piece 2.3, wherein: the first valve rod 2.1 is internally provided with a channel 2.4 communicated with first oil ducts a at two sides of the first valve rod, the valve core 2.2 is movably and hermetically arranged in the channel 2.4, the first reset piece 2.3 is a metal spring, the left end of the first reset piece is connected with the valve core 2.2, and the right end of the first reset piece is fixed at the right end of the first oil duct a; when the first oil duct a is in a structure that the right port is communicated with the outside of the valve body 1, the seal head 2.5 is connected to the right port in a threaded manner, at the moment, the right end of the first resetting piece 2.3 is in a contact state with the inner surface of the seal head 2.5, and the valve core 2.2 is in a state of blocking the channel 2.4 by extruding the first resetting piece 2.3 through the seal head 2.5. Further, the contact state may be that the right end of the first reset piece 2.3 is connected to the inner surface of the end enclosure 2.5, or that the right end of the first reset piece 2.3 abuts against the inner surface of the end enclosure 2.5.

The left end of the channel 2.4 is an oil inlet end of the reset type pilot valve 2, the right end of the channel is an oil outlet end of the reset type pilot valve 2, namely the oil inlet end of the reset type pilot valve 2 is located at the oil inlet P1 side, the oil outlet end of the position type pilot valve 2 is far away from the oil inlet P1, so that the valve core 2.2 is opened after hydraulic oil from the oil inlet P1 exceeds the set pressure of the reset type pilot valve 2, the first oil duct a is communicated with the third oil duct c, unloading is facilitated, and the set pressure of the reset type pilot valve 2 can be achieved according to the setting of the elastic force of the first reset piece 2.3.

Further, the first check valve 3 is connected to the left end of the first valve rod 2.1 and communicated with the channel 2.4 in the first valve rod 2.1, that is, the first check valve 3 is connected to the oil inlet end of the reset pilot valve 2, and the main purpose is to prevent the reverse flow of hydraulic oil, and to ensure that the reset main valve 4 can be opened to communicate the second oil passage b with the main valve cavity d and further with the oil outlet T on the valve body 1 to realize low-pressure unloading under the condition that the maximum oil pressure of the steering system is lower than the set pressure of the equivalent unloading valve.

For the third oil duct c, the third oil duct c is vertically arranged in the valve body 1, the upper port of the third oil duct c is connected with the right end of the first oil duct a above the third oil duct c, and the connection position is located on the right side of the oil outlet end of the reset pilot valve 2, so that after the valve core 2.2 in the reset pilot valve 2 is opened, hydraulic oil in the first oil duct a enters the third oil duct c and further enters the main valve cavity d, and therefore, the lower port of the third oil duct c is communicated with the main valve cavity d below the third oil duct c.

Further, the main valve cavity d is horizontally arranged and penetrates through the cylindrical cavity of the valve body 1, the second oil passage b is vertically arranged at the left part in the valve body 1, the upper port of the second oil passage b is communicated with the oil inlet P1, and the lower port of the second oil passage b is communicated with the left part of the main valve cavity d. The left and right ports of the main valve cavity d are both in threaded connection with plugs 5; on the one hand, such a through-type main valve chamber d is easy to implement during the actual production, and on the other hand, it is easy to install the reset main valve 4 in the main valve chamber d.

For the reset main valve 4, when the plug 5 seals in the main valve chamber d, and the reset main valve 4 is pressed to the left part of the main valve chamber d by the hydraulic oil from the third oil passage c, the second oil passage b communicates with the main valve chamber d, and for this purpose, a specific embodiment is as follows: reset main valve 4 includes cylindrical second valve rod 4.1, the second piece 4.2 that resets, wherein: the second reset piece 4.2 is a metal spring, the spring is horizontally arranged at the left part in the main valve cavity d, the left end of the spring is connected with or abutted against the inner wall of the plug 5 on the left port of the main valve cavity d, and the right end of the spring is connected with or abutted against the left end face of the second valve rod 4.1. In addition, grooves can be formed in the inner wall surface of the plug 5 and the left end surface of the second valve rod 4.1, two ends of the spring are respectively located in the grooves of the plug 5 and the second valve rod 4.1, and the structural design can support the spring, so that the inner wall of the main valve cavity d is prevented from being abraded in the spring stretching process, and the sealing performance between the main valve cavity d and the second oil duct b is prevented from being affected.

Further, the diameters of the two ends of the second valve rod 4.1 are larger than the middle diameter, and when the second valve rod 4.1 is in an uncompressed state, the left side wall of the second valve rod 4.1 contacts with the inner wall of the main valve cavity d to close the lower end of the second oil passage b, and the right side wall of the second valve rod 4.1 always contacts with the inner wall of the main valve cavity d to prevent oil leakage, so that the second valve rod 4.1 cannot be compressed leftward, and the second oil passage b is communicated with the main valve cavity d.

A counter bore 4.3 is formed in the end face of the right end of the second valve rod 4.1, the throttle hole j is formed in the right side wall of the second valve rod 4.1, and two ends of the throttle hole j are respectively communicated with the counter bore 4.3 and the oil outlet T, so that an oil duct in the valve body 1 can be communicated with the outside of the valve body 1, and smooth unloading and oil outlet are ensured.

The plug 5 on the right port of the main valve cavity d is provided with an external control port k which is communicated with the inside and the outside of the main valve cavity d, and a second one-way valve 6 which only allows liquid to enter from the outside is connected in the external control port k, so that the second valve rod 4.1 is compressed leftwards through external control hydraulic oil, the second oil duct b is further communicated with the main valve cavity d, the hydraulic oil from the first oil duct a is directly discharged from an oil outlet T after passing through the second oil duct b and the main valve cavity d, and low-pressure unloading is realized. In the process, as the external control hydraulic oil enters the throttling hole j from the counter bore 4.3 and then enters the oil outlet T from the throttling hole j, a pressure difference is generated, the second valve rod 4.1 can be moved to the left and is kept in the state under the hydraulic oil pressure, and when the external control hydraulic oil is cut off, the second valve rod 4.1 is reset.

On the basis of the unloading valve shown in fig. 4 and 5, referring to fig. 6, a hydraulic multi-pump confluence system of a loader is illustrated, and the system utilizes the novel unloading valve and the reversing valve 11 to merge the redundant flow in a steering pump into the oil output of the working pump 16, so that the driving force of the working system 10 is improved, the purpose of lifting for walking under the lifting and walking composite working condition is realized, and the working efficiency of the loader is effectively improved. Specifically, the method comprises the following steps:

the loader hydraulic pressure multi-pump confluence system includes: the flow valve 7, the steering system 8, the unloading valve 9, the working system 10, the reversing valve 11, the pilot pump 12 and the pilot control system 13, wherein: the oil inlet of the flow valve 7 is communicated with an oil tank 15 through a steering pump 14, the oil outlet of the flow valve 7 is communicated with the oil inlets of the steering system 8 and the unloading valve 9, the working system 10 is connected through a working pump 16, the working pump 16 is connected with the oil tank 15, and the oil outlet T of the unloading valve 9 is connected with an oil outlet pipeline of the working pump 16 to the working system 10, so that redundant flow in the steering pump 14 is merged into oil outlet of the working pump 16, and the driving force of the working system 10 is improved. An oil outlet of the pilot pump 12 is connected with an outer control port of the unloading valve 9 through a reversing valve 11, an oil inlet and an oil outlet of the pilot pump 12 are respectively communicated with an oil tank 15 and a pilot operation system 13, and the pilot operation system 13 is communicated with a working system 10. The reversing valve 11 is an electromagnetic reversing valve 11, and is mainly used for realizing the cooperative work with the pilot pump 12 through the on-off of the reversing valve 11, and further starting the unloading valve 9 to unload the low pressure under the condition that the oil pressure of the steering system 8 is lower than that of the unloading valve 9.

Furthermore, the loader hydraulic multi-pump confluence system further comprises a relief valve 17 for communicating the pilot control system 13 with the oil tank 15, so as to prevent the pilot control system 13 from working due to excessive oil pressure.

It can be seen that the novel unloading valve and the loader hydraulic multi-pump confluence system are characterized in that: first, in comparison with the unloading valve shown in fig. 1 and 2, the unloading valve shown in fig. 4 and 5, which is modified according to the present invention, is provided with an external control port k in the plug 5, and a second check valve 6 that allows only the external liquid to enter the valve body 1 is provided in the external control port k. On the basis, when the unloading valve and the reversing valve 11 are combined in a hydraulic multi-pump confluence system of a loader, the following technical advantages are achieved: when the loader is in a combined lifting and walking condition, the working system 10 is required to have large lifting force and driving force, but the lifting speed requirement is not high, at the moment, the electromagnetic directional valve 11 is electrified through the button to be opened, partial pressure oil in the pilot pump 12 enters the main valve cavity d through the directional valve 11, the second valve rod 4.1 is moved to the left under the pressure of the pressure oil and maintains the state under the pressure of the hydraulic oil, the second oil duct b is communicated with the main valve cavity d, so that the hydraulic oil from the first oil duct a is directly discharged from the oil outlet T after passing through the second oil duct b and the main valve cavity d, because the oil outlet T is connected with the oil outlet pipeline of the working pump 16 to the working system 10, the redundant flow in the steering pump 14 is merged into the oil outlet of the working pump 16, the driving force of the working system 10 is increased, and part of hydraulic oil enters the pilot control system 13 to control the working system 10 to carry out lifting operation while the pilot pump 12 discharges oil to the unloading valve 9. After the composite working condition is finished, the reversing valve 11 is closed, the quick switching between the two working conditions is realized, the composite action state of lifting and walking can be met, the normal working condition (no special requirement on driving force) can be met, and the working efficiency is improved.

Finally, any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.