Hydraulic control valve group of lifting system and electric wheel mine truck

Abstract

The invention discloses a lifting system hydraulic control valve bank and an electric wheel mine truck. The lifting system hydraulic control valve bank comprises a lifting system hydraulic control valve bank valve block. A circulation pipeline; a high-pressure filter; a lifting valve group; a forced landing valve group; the unloading valve group is arranged on the valve block, an oil inlet of the unloading valve group is communicated with the valve group oil inlet, an oil outlet of the unloading valve group is communicated with the valve group oil return port, and the unloading valve group and a pipeline communicated with the unloading valve group form an unloading pipeline communicated with the valve group oil inlet and the valve group oil return port. By arranging the unloading valve group and the unloading pipeline communicated with the unloading valve group, the effect that oil liquid directly flows back to the oil return port of the valve group from the oil inlet of the valve group through the unloading pipeline and does not flow through the high-pressure filter under the maintaining working condition and the floating working condition is achieved; the problems that in the prior art, an unloading loop is large in pressure loss, high in heat productivity and remarkable in oil liquid temperature rise, and a high-pressure filter needs to be replaced frequently are solved. And meanwhile, the integration level, the maintenance convenience and the system reliability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic systems, in particular to a lifting system hydraulic control valve group and an electric wheel mining truck. BACKGROUND

[0002] With the growing demand for the development of medium and large tonnage electric wheel mining trucks above 200 tons, the increasing requirements for the reliability, integration rate and maintenance convenience of these truck models, and the increasing demand for the platformization, modularization rate and intelligentization of hydraulic systems, the hydraulic valve group needs to have the characteristics of low heat generation, low failure rate, low cost and high integration.

[0003] The hydraulic lifting system of the electric wheel mining truck is generally a large-flow constant-flow system, and the working conditions are divided into lifting, maintaining, floating and forced landing, which are controlled by the lifting handle. It only operates at the rated working pressure in the lifting and forced landing states, and operates at a very low working pressure in the non-lifting and non-forced landing conditions (unloading condition), so that the oil pumped from the oil tank flows back to the oil tank, thereby reducing the heat generation of the lifting hydraulic system. Most of the heat generation of the lifting hydraulic system comes from the heat generation under the unloading condition, which depends on the flow size of the lifting system and the pressure loss on the unloading oil circuit. The hydraulic components on the unloading oil circuit generally include filters, pumps, unloading solenoid valves and pipelines, etc. The filter is the main source of pressure loss on the unloading oil circuit. Under the rated flow, the filter pressure loss can reach more than 5 bar. Since the hydraulic lifting system of the medium and large tonnage electric wheel mining truck has a large flow, even if the pressure loss of the unloading circuit only increases by 5 bar, the oil balance temperature will increase by 10-20℃. Therefore, the pressure loss of the unloading circuit is an important indicator for measuring the heat generation of the lifting hydraulic system.

[0004] At present, the lifting valve group of many medium and large tonnage mining dump trucks of many companies adopts the lifting control valve scheme of Husco Company and Parker Company. These schemes have high cost and the following problems: 1. Significant oil temperature rise under unloading condition (including maintaining condition and floating condition): under the unloading condition, the oil still needs to flow through the external high-pressure filter, resulting in large system pressure loss, high heat generation, significant oil temperature rise, and reduced performance and service life of the hydraulic system; 2. Frequent replacement of high-pressure filters: because the oil needs to flow through the high-pressure filter at any working condition, the online use time of the high-pressure filter is long, and it needs to be replaced frequently; 3. Complex pipeline connection: the external high-pressure filter and the dispersedly arranged valve pieces result in a large number of connection pipelines and complex spatial layout, making maintenance difficult.

[0005] Therefore, it is necessary to develop a high-integration platform lifting system hydraulic control valve group and an electric wheel mining truck using the control valve group to solve the above problems. SUMMARY

[0006] In view of the above deficiencies of the prior art, the present application provides a lifting system hydraulic control valve group and an electric wheel mining truck for solving at least one of the above technical problems.

[0007] The present application provides the following technical solutions: In a first aspect, the present application provides a lifting system hydraulic control valve group, comprising: a valve block; a flow pipe arranged in the valve block and connected with a valve group oil inlet and a valve group oil return outlet; a high-pressure filter arranged on the valve block and connected with the flow pipe; a lifting valve group arranged on the valve block and connected with the flow pipe, which controls the flow pipe to form a lifting pipe; a forced landing valve group arranged on the valve block and connected with the flow pipe, which controls the flow pipe to form a forced landing pipe; and a unloading valve group arranged on the valve block, with an oil inlet connected with the valve group oil inlet and an oil outlet connected with the valve group oil return outlet, the unloading valve group and the pipes connected therewith forming an unloading pipe connected with the valve group oil inlet and the valve group oil return outlet.

[0008] In an embodiment, the flow pipe is also connected with a first valve group oil outlet and a second valve group oil outlet arranged on the surface of the valve block, the valve group oil inlet is connected with an oil pump, the first valve group oil outlet is connected with a rodless cavity of an oil cylinder, the second valve group oil outlet is connected with a rod cavity of the oil cylinder, and the valve group oil return outlet is connected with an oil tank; the unloading valve group comprises an unloading cover plate valve and an unloading electromagnetic valve, the unloading cover plate valve is connected to the flow pipe, and the unloading electromagnetic valve controls the opening and closing of the unloading cover plate valve.

[0009] In an embodiment, the lifting valve group comprises a lifting cover plate valve, a lifting return oil cover plate valve, and a lifting electromagnetic valve, the lifting cover plate valve is arranged on a pipe connected with the high-pressure filter and the first valve group oil outlet, the lifting return oil cover plate valve is arranged on a pipe connected between the second valve group oil outlet and the valve group oil return outlet, and the lifting electromagnetic valve controls the opening and closing of the lifting cover plate valve and the lifting return oil cover plate valve.

[0010] In an embodiment, the forced landing valve group comprises a forced landing cover plate valve, a forced landing return oil cover plate valve, and a forced landing electromagnetic valve, the forced landing cover plate valve is arranged on a pipe connected between the high-pressure filter and the second valve group oil outlet, the forced landing return oil cover plate valve is arranged on a pipe connected between the first valve group oil outlet and the valve group oil return outlet, and the forced landing electromagnetic valve controls the opening and closing of the forced landing cover plate valve and the forced landing return oil cover plate valve.

[0011] In one embodiment, the valve group oil inlet comprises a first oil inlet and a second oil inlet, the number of high-pressure filters is two, which are arranged on the pipelines connecting the first oil inlet and the second oil inlet, the first valve group oil outlet comprises a first oil outlet and a second oil outlet, the second valve group oil outlet comprises a third oil outlet and a fourth oil outlet, the oil cylinder comprises a first oil cylinder and a second oil cylinder, the first oil outlet and the third oil outlet are connected to the first oil cylinder, the second oil outlet and the fourth oil outlet are connected to the second oil cylinder, and the valve group oil return port comprises a first oil return port and a second oil return port.

[0012] In one embodiment, the lifting system hydraulic control valve group further comprises a merging valve group, the merging valve group comprises a merging solenoid valve and a merging cover plate valve, the valve group oil inlet further comprises a third oil inlet, the oil inlet of the merging cover plate valve is connected to the third oil inlet, the oil outlet of the merging cover plate valve is connected to the oil outlet pipeline of the high-pressure filter, and the merging solenoid valve controls the opening and closing of the merging cover plate valve.

[0013] In one embodiment, the lifting system hydraulic control valve group further comprises a floating valve group, the floating valve group comprises a first floating cover plate valve, a first floating solenoid valve, a second floating cover plate valve and a second floating solenoid valve, the first floating cover plate valve is arranged on the pipeline connecting the forced landing oil return cover plate valve and the valve group oil return port, the first floating solenoid valve controls the opening and closing of the first floating cover plate valve, the second floating cover plate valve is arranged on the pipeline connecting the first floating cover plate valve and the lifting oil return cover plate valve, and the second floating solenoid valve controls the opening and closing of the second floating cover plate valve.

[0014] In one embodiment, the lifting system hydraulic control valve group further comprises a balancing valve group, the balancing valve group comprises a first balancing valve and a second balancing valve arranged in parallel between the lifting oil return cover plate valve and the second valve group oil outlet.

[0015] In one embodiment, a supplement solenoid valve is arranged in parallel with the first balancing valve and the second balancing valve between the lifting oil return cover plate valve and the second valve group oil outlet.

[0016] In the second aspect, the application provides an electric wheel mining truck comprising the lifting system hydraulic control valve group.

[0017] Compared with the prior art, the application has the following beneficial effects: The present application realizes the effect that oil liquid directly flows back to the oil return port of the valve group through the unloading pipeline without flowing through the high-pressure filter when maintaining the working condition and the floating condition, solves the problems of large pressure loss, high heat generation, significant oil temperature rise and frequent replacement of the high-pressure filter in the prior art. Meanwhile, by integrating the high-pressure filter, the lifting valve group, the forced lowering valve group and the unloading valve group on the valve block, the pipeline connection is simplified, the system complexity and failure rate are reduced, and the integration, maintenance convenience and system reliability are improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] In the following, the present application will be described in more detail based on embodiments and with reference to the drawings.

[0019] Figure 1 Fig. 1 is a structural schematic diagram of a three-stage lifting oil cylinder; Figure 2 Fig. 2 is a schematic diagram of a lifting system hydraulic control valve group provided by the present application; Figure 3 Fig. 3 is a three-dimensional view of the lifting system hydraulic control valve group; Figure 1 ; Figure 4 Fig. 4 is a three-dimensional view of the lifting system hydraulic control valve group; Figure 2 .

[0020] Reference signs: 1, high-pressure filter; 2, unloading cover valve; 3, unloading solenoid valve; 4, confluence solenoid valve; 5, confluence cover valve; 6, lifting cover valve; 7, lifting solenoid valve; 8, forced lowering oil return cover valve; 9, first floating cover valve; 10, first floating solenoid valve; 11, second floating cover valve; 12, second floating solenoid valve; 13, lifting oil return cover valve; 14, first balance valve; 15, second balance valve; 16, oil supplement solenoid valve; 17, forced lowering solenoid valve; 18, forced lowering cover valve; I, first-stage cylinder; II, second-stage cylinder; III, third-stage cylinder; P1, first oil inlet; P2, second oil inlet; P3, third oil inlet; A1, first oil outlet; A2, second oil outlet; B1, third oil outlet; B2, fourth oil outlet; T, first oil return port; T1, second oil return port. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0022] In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0023] In addition, if there are terms such as "first", "second", these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In the present application, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] In the present application, unless otherwise explicitly specified and limited, if there are similar descriptions such as "first feature on or under second feature", the meaning can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" of the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" of the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0026] It is to be noted that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it is to be understood that when a method is referred to as comprising a step or comprising a combination of steps, the method can include additional or other steps even though not explicitly defined in the specification.

[0027] The application will be illustrated in detail below with reference to the accompanying drawings. Figures 1 to 4 The application will be illustrated in detail below with reference to the accompanying drawings.

[0028] For the purpose of better understanding, four working conditions of the lifting system will be described.

[0029] The working conditions of the lifting system include lifting, holding, floating and forced landing, which are controlled by the lifting handle. As shown in the figure, the multi-stage oil cylinder is generally used in the electric transmission mine dump truck, and the three-stage oil cylinder is taken as an example. The first-stage cylinder I is a plunger rod, and the second-stage cylinder II and the third-stage cylinder III are piston cylinders. The large cavity of the first-stage cylinder I, the large cavity of the second-stage cylinder II and the large cavity of the third-stage cylinder III are connected with the A port of the lifting oil cylinder, and the small cavities of the second-stage cylinder II and the third-stage cylinder III are connected with the B port of the lifting oil cylinder. Figure 1 When the lifting system is in the lifting working condition, the oil flows into the lifting oil cylinder from the A port and flows back to the oil tank from the B port of the lifting oil cylinder, at this time, the oil cylinder is in the elongation state.

[0030] When the lifting system is in the holding working condition, the A port and the B port of the lifting oil cylinder are sealed, and no oil flows into and out of the lifting oil cylinder, at this time, the oil cylinder is in the holding state.

[0031] When the lifting system is in the forced landing working condition, the oil flows into the lifting oil cylinder from the B port and flows back to the oil tank from the A port of the lifting oil cylinder, at this time, the oil cylinder is in the retraction state.

[0032] When the lifting system is in the floating working condition, the A port and the B port of the lifting oil cylinder are connected with the oil tank at the same time, and under the action of the gravity of the cargo tank, the oil cylinder is subjected to pressure at both ends, at this time, the oil cylinder is in the retraction state.

[0033] The difference between the floating and forced landing working conditions is that in the floating process, the A port and the B port of the lifting oil cylinder are not connected with the pressure oil source, and part of the oil flowing out of the A port flows to the B port, and the other part flows back to the oil tank. In the forced landing process, the B port is connected with the pressure oil source, and the oil in the A port flows back to the oil tank.

[0034] Example 1

[0035] As shown in the figure, the multi-stage oil cylinder is generally used in the electric transmission mine dump truck, and the three-stage oil cylinder is taken as an example. The first-stage cylinder I is a plunger rod, and the second-stage cylinder II and the third-stage cylinder III are piston cylinders. The large cavity of the first-stage cylinder I, the large cavity of the second-stage cylinder II and the large cavity of the third-stage cylinder III are connected with the A port of the lifting oil cylinder, and the small cavities of the second-stage cylinder II and the third-stage cylinder III are connected with the B port of the lifting oil cylinder. Figures 2 to 4 ​As shown, the embodiment provides a lifting system hydraulic control valve group, which comprises a valve block, a flow pipe arranged in the valve block, a high-pressure filter 1, a lifting valve group, a forced lowering valve group, and an unloading valve group. The flow pipe is connected with a valve group oil inlet arranged on the surface of the valve block, a first valve group oil outlet, a second valve group oil outlet, and a valve group oil return port. The valve group oil inlet is connected with an oil pump, which can be a gear pump or a gear series pump. The first valve group oil outlet is connected to a rodless chamber of a cylinder (lifting cylinder A port), the second valve group oil outlet is connected to a rod chamber of the cylinder (lifting cylinder B port), and the valve group oil return port is connected with an oil tank. The valve block is provided with the high-pressure filter 1, which is in communication with the flow pipe and is used to filter impurities in the oil in the flow pipe. The lifting valve group comprises a lifting cover plate valve 6 and a lifting return oil cover plate valve 13. The lifting cover plate valve 6 is arranged on the pipe between the high-pressure filter 1 and the first valve group oil outlet, and the lifting return oil cover plate valve 13 is arranged on the pipe between the second valve group oil outlet and the valve group oil return port. The forced lowering valve group comprises a forced lowering cover plate valve 18 and a forced lowering return oil cover plate valve 8. The forced lowering cover plate valve 18 is arranged on the pipe between the high-pressure filter 1 and the second valve group oil outlet, and the forced lowering return oil cover plate valve 8 is arranged on the pipe between the first valve group oil outlet and the valve group oil return port. The unloading valve group is arranged on the flow pipe. The oil inlet of the unloading valve group is in communication with the oil inlet pipe of the high-pressure filter 1, and is also in communication with the valve group oil inlet. The oil outlet of the unloading valve group is in communication with the valve group oil return port. The unloading valve group and the pipe in communication therewith form an unloading pipe which is in communication with the valve group oil inlet and the valve group oil return port. In the holding mode and the floating mode, the unloading valve group controls the unloading pipe to be conducted and controls other valve groups to be closed. After the oil flows from the valve group oil inlet into the flow pipe, the oil directly flows to the valve group oil return port through the unloading pipe and returns to the oil tank, without flowing through the high-pressure filter 1. Figure 2 In some embodiments, the other oil ports are pressure measuring ports or sealing ports.

[0036] The present application realizes the effect that the oil can be directly unloaded to the oil tank without passing through the high-pressure filter 1 in the holding mode and the floating mode by arranging the flow pipe integrated in the valve block and cooperating with the lifting valve group, the forced lowering valve group, and the independent unloading pipe formed by the unloading valve group, thereby solving the technical problems of large system pressure loss, high energy consumption, easy clogging of the high-pressure filter 1, and short service life of the traditional lifting hydraulic system in the non-lifting mode.

[0037] In some embodiments, the unloading valve group comprises an unloading cover plate valve 2 and an unloading electromagnetic valve 3. The unloading cover plate valve 2 is connected to the flow pipe, and the unloading electromagnetic valve 3 controls the opening and closing of the unloading cover plate valve 2. Preferably, the unloading valve group adopts a pilot control structure.

[0038] In some embodiments, the lifting valve group further comprises a lifting solenoid valve 7, which controls the opening and closing of the lifting cover plate valve 6 and the lifting return cover plate valve 13. Preferably, the unloading valve group adopts a pilot control structure, and the synchronous opening and closing of the lifting cover plate valve 6 and the lifting return cover plate valve 13 are simultaneously controlled by one lifting solenoid valve 7, which reduces the cost and can make the valve body smaller.

[0039] In some embodiments, the forced landing valve group further comprises a forced landing solenoid valve 17, which controls the opening and closing of the forced landing cover plate valve 18 and the forced landing return cover plate valve 8. Preferably, the forced landing valve group adopts a pilot control structure, and the synchronous opening and closing of the forced landing cover plate valve 18 and the forced landing return cover plate valve 8 are simultaneously controlled by one forced landing solenoid valve 17, which reduces the cost and can make the valve body smaller.

[0040] In some embodiments, the valve group oil inlet includes a first oil inlet P1 and a second oil inlet P2, the number of high-pressure filters 1 is two, and they are arranged in parallel and are arranged on the pipelines communicating the first oil inlet P1 and the second oil inlet P2, the first valve group oil outlet includes a first oil outlet A1 and a second oil outlet A2, the second valve group oil outlet includes a third oil outlet B1 and a fourth oil outlet B2, the oil cylinder includes a first oil cylinder and a second oil cylinder, the first oil outlet A1 and the third oil outlet B1 are connected to the first oil cylinder, the second oil outlet A2 and the fourth oil outlet B2 are connected to the second oil cylinder, and the valve group return oil port includes a first return oil port T and a second return oil port T1. By arranging multiple parallel paths for the oil inlet, the high-pressure filter 1, the oil outlet, and the return oil port, the overall oil supply capacity and operation efficiency of the system can be effectively improved, synchronous control of the double oil cylinders can be realized, the flexibility and reliability of the system configuration are enhanced, and it is suitable for medium and large tonnage electric wheel mining trucks, for example, the first oil cylinder is a left lifting oil cylinder, and the second oil cylinder is a right lifting oil cylinder.

[0041] In some embodiments, the lifting system hydraulic control valve group further comprises a merging valve group, which includes a merging solenoid valve 4 and a merging cover plate valve 5, the valve group oil inlet further includes a third oil inlet P3, the oil inlet of the merging cover plate valve 5 communicates with the third oil inlet P3, the oil outlet of the merging cover plate valve 5 communicates with the oil outlet pipeline of the high-pressure filter 1, and the merging solenoid valve 4 controls the opening and closing of the merging cover plate valve 5. The merging valve group functions to make the oil of the third oil inlet P3 merge with the oil of the first oil inlet P1 and the second oil inlet P2. The third oil inlet P3 is connected to a steering constant pressure variable pump, and when the lifting system is not lifting, the merging valve group is closed, and only the first oil inlet P1 and the second oil inlet P2 inlet oil.

[0042] In some embodiments, the lifting system hydraulic control valve group further comprises a floating valve group, the floating valve group comprising a first floating cover plate valve 9, a first floating electromagnetic valve 10, a second floating cover plate valve 11 and a second floating electromagnetic valve 12, the first floating cover plate valve 9 being arranged on a pipeline communicating between the emergency return oil cover plate valve 8 and the valve group return oil outlet, the first floating electromagnetic valve 10 controlling opening and closing of the first floating cover plate valve 9, the second floating cover plate valve 11 being arranged on a pipeline communicating between the first floating cover plate valve 9 and the lifting return oil cover plate valve 13, and the second floating electromagnetic valve 12 controlling opening and closing of the second floating cover plate valve 11.

[0043] In some embodiments, the lifting system hydraulic control valve group further comprises a balance valve group, the balance valve group comprising a first balance valve 14 and a second balance valve 15 arranged in parallel between the lifting return oil cover plate valve 13 and the second valve group oil outlet. The first balance valve 14 and the second balance valve 15 are arranged to generate back pressure at the lifting cylinder B port during lifting of the cargo box, so as to stabilize lifting.

[0044] In some embodiments, a supplement electromagnetic valve 16 is arranged in parallel with the first balance valve 14 and the second balance valve 15 between the lifting return oil cover plate valve 13 and the second valve group oil outlet. The supplement electromagnetic valve 16 is opened when the cargo box floats down, to supplement oil to the lifting cylinder B port, so as to prevent negative pressure from being generated in the small cavity of the lifting cylinder, causing cylinder pulling.

[0045] As shown in Figure 3 and Figure 4 , the first balance valve 14 and the second balance valve 15 and the supplement electromagnetic valve 16 are in the form of spool, fixed on the valve body through the plug-in hole. The high-pressure filter 1, each cover plate valve and the electromagnetic valve carried by each cover plate valve are all plate-connected, fixed on the valve body through bolts.

[0046] The specific oil circuit of the lifting system hydraulic control valve group provided in the embodiment is as follows in four working conditions: Lifting working condition In the lifting condition, the lifting handle controls the lifting solenoid valve 7 to be powered on, the lifting valve group is opened (the lifting cover plate valve 6 and the lifting return oil cover plate valve 13 are both opened), and other valve groups are all closed, that is, the forced landing valve group is closed (the forced landing solenoid valve 17 controls the forced landing return oil cover plate valve 8 and the forced landing cover plate valve 18 to be closed), the unloading valve group is closed (the unloading solenoid valve 3 controls the unloading cover plate valve 2 to be closed), the floating valve group is closed (the first floating solenoid valve 10 controls the first floating cover plate valve 9 to be closed, and the second floating solenoid valve 12 controls the second floating cover plate valve 11 to be closed), and the oil supplement solenoid valve 16 is closed. The oil from the oil pump flows into the valve group inlet, is filtered through the high-pressure filter 1, enters the lifting cover plate valve 6, and finally enters the rodless chamber of the oil cylinder (the lifting oil cylinder A port) from the first valve group outlet, so as to push the oil cylinder to be elongated. At the same time, the oil in the rod chamber of the oil cylinder (the lifting oil cylinder B port) flows out from the second valve group outlet, passes through the balance valve group (the first balance valve 14 and the second balance valve 15 generate back pressure to ensure that the lifting is stable) and the lifting return oil cover plate valve 13, and then flows back to the tank from the valve group return port.

[0047] In this condition, the combined valve group can be opened. If the third inlet P3 is used, the combined solenoid valve 4 controls the combined cover plate valve 5 to be opened, so that the oil of the steering constant pressure variable pump is combined, and the lifting speed is increased.

[0048] Forced landing condition In the forced landing condition, the forced landing valve group is opened (the forced landing solenoid valve 17 is powered on, and the forced landing cover plate valve 18 and the forced landing return oil cover plate valve 8 are opened), the lifting valve group is closed, the unloading valve group is closed, the floating valve group is closed, the oil supplement solenoid valve 16 is closed, and the balance valve group is opened (the first balance valve 14 and the second balance valve 15 are both opened). The oil from the oil pump flows into the valve group inlet, is filtered through the high-pressure filter 1, enters the forced landing cover plate valve 18, passes through the balance valve group, enters the rod chamber of the oil cylinder from the second valve group outlet (the lifting oil cylinder B port), and pushes the oil cylinder to be retracted. At the same time, the oil in the rodless chamber of the oil cylinder (the lifting oil cylinder A port) flows out from the first valve group outlet, passes through the forced landing return oil cover plate valve 8, and then flows back to the tank from the valve group return port.

[0049] Maintaining condition In the maintaining condition, all valve groups except the unloading valve group are closed, and only the unloading valve group is opened (the unloading solenoid valve 3 is powered on, and the unloading cover plate valve 2 is opened). The A port and the B port of the lifting oil cylinder are sealed by the lifting valve group and the forced landing valve group, no oil flows into or out of the oil cylinder, and the oil cylinder maintains the current position. The oil from the oil pump flows into the valve group inlet, directly flows back to the tank through the unloading pipeline formed by the unloading valve group, and does not flow through the high-pressure filter 1, so as to reduce the system pressure loss and energy consumption.

[0050] Unloading oil circuit: oil pump→valve group inlet→unloading valve group (unloading cover plate valve 2)→valve group return port→tank.

[0051] Floating condition In the floating working condition, the unloading valve group is opened (the unloading electromagnetic valve 3 is powered on, and the unloading cover plate valve 2 is opened), the floating valve group is opened (the first floating electromagnetic valve 10 and the second floating electromagnetic valve 12 are powered on, and the first floating cover plate valve 9 and the second floating cover plate valve 11 are opened), the lifting valve group is closed, the forced lowering valve group is closed, and the oil supplementing electromagnetic valve 16 is opened. The oil from the oil pump directly returns to the oil tank through the unloading pipeline without flowing through the high-pressure filter 1. At the same time, the oil cylinder is retracted under the gravity of the cargo box, and the oil in the rodless cavity (the A port of the lifting oil cylinder) of the oil cylinder first passes through the forced lowering return oil cover plate valve 8 (at this time, the forced lowering return oil cover plate valve 8 is closed, and the vertical oil port is closed, but the side can still be communicated), then passes through the first floating cover plate valve 9, and then part of the oil flows back to the oil tank through the valve group return oil port, and the other part of the oil passes through the second floating cover plate valve 11, then passes through the lifting return oil cover plate valve 13 (at this time, the lifting return oil cover plate valve 13 is closed, and the vertical oil port is closed, but the side can still be communicated), passes through the first balance valve 14, the second balance valve 15 and the oil supplementing electromagnetic valve 16, and then is supplemented to the rod cavity (the B port of the lifting oil cylinder) of the oil cylinder to prevent the negative pressure in the B port of the lifting oil cylinder from causing the "cylinder pulling" phenomenon. The lifting oil cylinder is retracted, and the cargo box is in a descending state.

[0052] The unloading oil circuit: the oil pump→the valve group oil inlet port→the unloading valve group (the unloading cover plate valve 2)→the valve group return oil port→the oil tank.

[0053] Therefore, in the maintaining working condition and the floating working condition, the high-pressure filter 1 is not arranged in the unloading oil circuit, so that the lifting system hydraulic control valve group provided by the present application greatly reduces the system pressure loss of the lifting system in the two unloading working conditions of the maintaining working condition and the floating working condition, reduces the use time of the high-pressure filter 1, and solves the problems of large unloading circuit pressure loss, high heat generation, significant oil temperature rise and frequent replacement of the high-pressure filter 1 in the prior art.

[0054] Embodiment two The embodiment provides an electric wheel mine truck, which comprises the lifting system hydraulic control valve group provided in the embodiment one.

[0055] In conclusion, the present application realizes the effect that the oil directly flows back from the valve group oil inlet port to the valve group return oil port through the unloading pipeline without flowing through the high-pressure filter 1 in the maintaining working condition and the floating working condition, solves the problems of large unloading circuit pressure loss, high heat generation, significant oil temperature rise and frequent replacement of the high-pressure filter 1 in the prior art. At the same time, the high-pressure filter 1, the lifting valve group, the forced lowering valve group and the unloading valve group are highly integrated on the valve block, which simplifies the pipeline connection, reduces the system complexity and the failure rate, and improves the integration, the maintenance convenience and the system reliability.

[0056] The components and principles that are not described in detail in the present application can be realized by various structures and principles known in the prior art.

[0057] While the present application has been described with reference to the preferred embodiments, it is to be understood that various modifications can change the scope of the present application to which they are not intended to deviate. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided that there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A hydraulic control valve assembly for a lifting system, characterized in that, include: Valve block; A flow pipeline is installed inside the valve block and is connected to the valve group oil inlet and valve group oil return port. A high-pressure filter is installed on the valve block and is connected to the flow pipeline; A lifting valve assembly is mounted on the valve block and connected to the flow pipeline, controlling the flow pipeline to form a lifting pipeline. A forced landing valve assembly is installed on the valve block and connected to the flow pipeline, controlling the flow pipeline to form a forced landing pipeline. as well as An unloading valve assembly is installed on the valve block. Its oil inlet is connected to the oil inlet of the valve assembly, and its oil outlet is connected to the oil return port of the valve assembly. The unloading valve assembly and the pipeline connected to it constitute an unloading pipeline connecting the oil inlet of the valve assembly and the oil return port of the valve assembly.

2. The hydraulic control valve assembly for the lifting system according to claim 1, characterized in that, The flow pipeline is also connected to a first valve group oil outlet and a second valve group oil outlet provided on the surface of the valve block. The valve group oil inlet is connected to an oil pump, the first valve group oil outlet is connected to the rodless chamber of the oil cylinder, the second valve group oil outlet is connected to the rod chamber of the oil cylinder, and the valve group oil return port is connected to an oil tank. The unloading valve group includes an unloading cover valve and an unloading solenoid valve. The unloading cover valve is connected to the flow pipeline, and the unloading solenoid valve controls the opening and closing of the unloading cover valve.

3. The hydraulic control valve assembly for the lifting system according to claim 2, characterized in that, The lifting valve assembly includes a lifting cover valve, a lifting return cover valve, and a lifting solenoid valve. The lifting cover valve is installed on the pipeline connecting the high-pressure filter and the oil outlet of the first valve assembly. The lifting return cover valve is installed on the pipeline connecting the oil outlet of the second valve assembly and the oil return port of the valve assembly. The lifting solenoid valve controls the opening and closing of the lifting cover valve and the lifting return cover valve.

4. The hydraulic control valve assembly for the lifting system according to claim 2, characterized in that, The forced landing valve assembly includes a forced landing cover valve, a forced landing return cover valve, and a forced landing solenoid valve. The forced landing cover valve is installed on the pipeline connecting the high-pressure filter and the oil outlet of the second valve assembly. The forced landing return cover valve is installed on the pipeline connecting the oil outlet of the first valve assembly and the oil return port of the valve assembly. The forced landing solenoid valve controls the opening and closing of the forced landing cover valve and the forced landing return cover valve.

5. The hydraulic control valve assembly for the lifting system according to claim 2, characterized in that, The valve group has an oil inlet including a first oil inlet and a second oil inlet. There are two high-pressure filters, which are respectively installed on the pipeline connecting the first oil inlet and the second oil inlet. The first valve group has an oil outlet including a first oil outlet and a second oil outlet. The second valve group has an oil outlet including a third oil outlet and a fourth oil outlet. The oil cylinder includes a first oil cylinder and a second oil cylinder. The first oil outlet and the third oil outlet are connected to the first oil cylinder. The second oil outlet and the fourth oil outlet are connected to the second oil cylinder. The valve group has a return oil port including a first return oil port and a second return oil port.

6. The hydraulic control valve assembly for the lifting system according to claim 5, characterized in that, It also includes a confluence valve assembly, which includes a confluence solenoid valve and a confluence cover valve. The oil inlet of the valve assembly also includes a third oil inlet. The oil inlet of the confluence cover valve is connected to the third oil inlet. The oil outlet of the confluence cover valve is connected to the oil outlet pipeline of the high-pressure filter. The confluence solenoid valve controls the opening and closing of the confluence cover valve.

7. The hydraulic control valve assembly for the lifting system according to claim 6, characterized in that, It also includes a floating valve assembly, which includes a first floating cover valve, a first floating solenoid valve, a second floating cover valve, and a second floating solenoid valve. The first floating cover valve is disposed on the pipeline connecting the forced return oil cover valve and the return oil port of the valve assembly. The first floating solenoid valve controls the opening and closing of the first floating cover valve. The second floating cover valve is disposed on the pipeline connecting the first floating cover valve and the lifting return oil cover valve. The second floating solenoid valve controls the opening and closing of the second floating cover valve.

8. The hydraulic control valve assembly for the lifting system according to claim 7, characterized in that, It also includes a balance valve assembly, which includes a first balance valve and a second balance valve arranged in parallel between the lifting return oil cover valve and the oil outlet of the second valve assembly.

9. The hydraulic control valve assembly for the lifting system according to claim 8, characterized in that, A replenishing solenoid valve is also provided between the lifting return oil cover valve and the oil outlet of the second valve group, which is connected in parallel with the first balance valve and the second balance valve.

10. An electric wheel mining truck, characterized in that, Includes the hydraulic control valve assembly for the lifting system as described in any one of claims 1-9.

Images