Multi-functional hydraulic system of tractor and control method thereof

Abstract

The application discloses a tractor multifunctional hydraulic system and a control method thereof, which comprises a hydraulic oil tank, a multi-way valve assembly, a speed regulating valve assembly and an oil cylinder. The speed regulating valve assembly comprises a descending speed regulating valve for realizing the descending speed regulation of the oil cylinder. The multi-way valve assembly comprises a first multi-way valve. A bypass is connected to an oil path between the first multi-way valve and the descending speed regulating valve. One end of a quick-change connector I is connected to the bypass. The first multi-way valve comprises a lifting position and a descending position. When the descending speed regulating valve is cut off and the first multi-way valve is controlled to the lifting position, the pressurized hydraulic oil is output to the outside of the system through the quick-change connector I. The scheme can realize the single-acting hydraulic output, the double-acting hydraulic output, the conversion and regulation of the single-acting and double-acting hydraulic output, the descending speed regulation function, the oil cylinder position locking function and the strong pressure into the earth switching function.

Description

Technical Field

[0001] The present invention belongs to the technical field of tractors, and in particular relates to a multifunctional hydraulic system for a tractor and a control method thereof. Background Art

[0002] With the popularization of composite agricultural implements, users' working methods have changed significantly. The promotion and use of straw return to the field and no-till seeding operations have led to an increasing demand from users for agricultural tractors equipped with forced soil-penetration configurations. In some areas, the use of chemical fertilizers has caused soil compaction, and users are also required to choose forced-pressure lifting devices. In addition, in order to achieve multi-purpose use of one machine, users need the hydraulic system of the tractor equipped with a forced soil-penetration device to be able to realize single-acting hydraulic output, double-acting hydraulic output, descending speed adjustment, cylinder position locking and other functions. The existing tractor hydraulic system has the following defects: 1. It can only meet the above-mentioned forced soil-penetration configuration function, and the conversion between forced pressure and non-forced pressure functions is inconvenient to control; 2. It is difficult to simultaneously meet the functional requirements of users for multiple operations; 3. Although some hydraulic systems can meet multiple functions at the same time, their pipeline design is complex, which is not convenient for design and manufacturing and is complex to control. Summary of the Invention

[0003] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a multifunctional hydraulic system for a tractor and a control method thereof. The device can be used under various working conditions of the tractor.

[0004] To achieve the above-mentioned objectives, one of the objectives of the present invention is to provide a multifunctional hydraulic system for a tractor, comprising a hydraulic oil tank, a multi-way valve assembly, a speed regulating valve assembly and a cylinder, the speed regulating valve assembly comprising a descent speed regulating valve for adjusting the descent speed of the cylinder, the multi-way valve assembly comprising a first multi-way valve, the oil circuit between the first multi-way valve and the descent speed regulating valve being connected with a bypass, one end of a quick-change connector I being connected to the bypass, the first multi-way valve comprising a lifting position and a descending position, when the descent speed regulating valve is cut off and the first multi-way valve is controlled to the lifting position, the pressurized hydraulic oil is output to the outside of the system through the quick-change connector I, and when the descent speed regulating valve is cut off and the first multi-way valve is controlled to the descending position, the hydraulic oil flows back to the hydraulic oil tank through the quick-change connector I and the first multi-way valve.

[0005] As a preferred solution, the second end of the descending speed regulating valve is connected to the lower chamber of the oil cylinder.

[0006] As a preferred solution, the upper chamber oil port of the cylinder is connected to two branches, wherein the first branch is connected to the first multi-way valve, and the second branch is connected to the hydraulic oil tank through the single-double-acting switching valve I, and the single-double-acting switching valve I is integrated in the multi-way valve assembly.

[0007] As a preferred solution, a hydraulic oil pump and an oil filter are further included, the inlet end of the hydraulic oil pump is communicated with the hydraulic oil tank through the oil filter, and the outlet end of the hydraulic oil pump is communicated with the oil circuit of the multi-way valve assembly.

[0008] As a preferred solution, the multi-way valve assembly further includes a second multi-way valve and a single / double-acting switching valve II, the oil supply ports of the second multi-way valve and the first multi-way valve are respectively connected with the outlet end of the hydraulic oil pump through a one-way valve, the single / double-acting switching valve II is integrated in the multi-way valve assembly, the first end of the single / double-acting switching valve II is connected with the first oil port of the second multi-way valve, and the second end of the single / double-acting switching valve II is connected with the hydraulic oil tank.

[0009] As a preferred solution, the first oil port of the second multi-way valve is connected with a quick-change connector II, the second oil port of the second multi-way valve is connected with the first end of a quick-change connector III, the second end of the quick-change connector III is communicated with the oil circuit between the single / double-acting switching valve II and the second multi-way valve, and the switching between the double-acting output function and the single-acting output function of the second multi-way valve is realized by controlling the communication and cut-off of the single / double-acting switching valve II.

[0010] The second object of the present application is to provide a control method of the multi-functional hydraulic system of the tractor, the multi-way valve assembly and the speed regulating valve assembly are jointly controlled or independently controlled according to different situations, and the specific control method is as follows.

[0011] I. strong pressure switching step: the single / double-acting switching valve I is cut off, the first multi-way valve is controlled to the lowering position, the high-pressure hydraulic oil is input from the first multi-way valve to the upper chamber of the oil cylinder, the strong pressure operation of the lifting device is realized, the single / double-acting switching valve I is connected, the first multi-way valve is controlled to the lowering position, the upper chamber of the oil cylinder is communicated with the hydraulic oil tank through the single / double-acting switching valve I, the high-pressure hydraulic oil is input from the first multi-way valve to the upper chamber of the oil cylinder, the oil circuit at the single / double-acting switching valve I is unloaded, and the non-strong pressure operation of the lifting device is realized;

[0012] II. lowering speed regulating step: when the oil cylinder is lowered, the opening degree of the lowering speed regulating valve is adjusted, so that the oil flow in the pipeline where the lowering speed regulating valve is located can be controlled, the lowering speed of the oil cylinder is regulated, and when the oil flow through the lowering speed regulating valve is 0, the pipeline where the lowering speed regulating valve is located is cut off.

[0013] III. single-acting output step: after the lowering speed regulating valve is cut off, the oil circuit between the oil cylinder and the first multi-way valve is cut off, the first multi-way valve is controlled to the lifting position, the high-pressure hydraulic oil is output to the outside of the system through the quick-change connector I, the single-acting output is realized, the first multi-way valve is controlled to the lowering position, the hydraulic oil returned from the outside of the system flows into the hydraulic oil tank through the quick-change connector I and the first multi-way valve, and the single-acting return is realized.

[0014] IV. Double-acting output step: control the single-double acting switch valve II to the cut-off state, the second multi-way valve realizes double-acting output, the second multi-way valve has a working position A and a working position B, control the second multi-way valve to the working position A, high-pressure hydraulic oil flows from the second multi-way valve to the outside of the system through the quick-change joint II, the other hydraulic oil is input through the quick-change joint III and returns to the hydraulic oil tank after passing through the second multi-way valve, control the second multi-way valve to the working position B, high-pressure hydraulic oil flows from the second multi-way valve to the outside of the system through the quick-change joint III, the other hydraulic oil is input through the quick-change joint II and returns to the hydraulic oil tank after passing through the second multi-way valve;

[0015] V. Single-acting switching step: control the single-double acting switch valve II to the connected state, the pipeline where the quick-change joint III is located is communicated with the hydraulic oil tank, control the second multi-way valve to the working position A, high-pressure hydraulic oil flows from the second multi-way valve to the outside of the system through the quick-change joint II; control the second multi-way valve to the working position B, hydraulic oil flows from the outside of the system through the quick-change joint II and returns to the hydraulic oil tank after passing through the second multi-way valve.

[0016] As a preferred scheme, in the high-pressure switching step, in the high-pressure operation mode, control the first multi-way valve to the lifting position, high-pressure hydraulic oil is input to the lower cavity of the oil cylinder through the first multi-way valve and the lowering speed regulating valve, the hydraulic oil in the upper cavity of the oil cylinder returns to the hydraulic oil tank through the first multi-way valve, control the first multi-way valve to the lowering position, high-pressure hydraulic oil is input to the upper cavity of the oil cylinder through the first multi-way valve, the hydraulic oil in the lower cavity of the oil cylinder returns to the hydraulic oil tank through the lowering speed regulating valve.

[0017] Advantageous effects

[0018] Firstly, the system is improved, which can realize the conversion and adjustment of single-acting hydraulic output, double-acting hydraulic output, single-double acting hydraulic output of the tractor, the lowering speed regulation function, the oil cylinder position locking function and the high-pressure earth switching function, thereby meeting the needs of various working conditions, and the scheme simplifies the pipeline of the hydraulic system, switches between various working conditions, and makes the operation very reliable and convenient. The specific analysis is as follows: the speed regulating valve assembly is arranged between the oil cylinder and the multi-way valve assembly, which can not only be used to realize the lowering speed regulation of the oil cylinder, but also can lock the oil cylinder when the flow of the lowering speed regulating valve is 0. At the same time, since the hydraulic output joint is arranged between the speed regulating valve assembly and the multi-way valve assembly, single-acting output to the outside of the system can be realized through the quick-change joint I when the lowering speed regulating valve is "locked".

[0019] Secondly, the scheme considers the need to output single-acting and double-acting functions to the outside system under specific working conditions, and a multi-way valve is connected in parallel to the main oil way interface of the first multi-way valve in the multi-way valve assembly, and a single / double-acting switching valve II is integrated at the second multi-way valve, so that the state conversion between the double-acting function and the single-acting function of the second multi-way valve can be controlled by controlling the conversion between the connection and the cut-off state of the single / double-acting switching valve II.

[0020] Thirdly, the control method of the hydraulic system is optimized, the control method of the scheme is matched with the hydraulic system with the specific structure described above, the switching of various function operation processes is strictly controlled, the switching mode between various working conditions is reasonably optimized, the sequence of the hydraulic control process under various working conditions is reasonably optimized, the hydraulic control steps and the valve switching are more simplified, not only the pipeline of the hydraulic system is optimized, but also the convenience and reliability of the hydraulic control operation are improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the application embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0022] Figure 1 The hydraulic schematic diagram of the multifunctional hydraulic system is improved;

[0023] Figure 2 The single-acting hydraulic output principle diagram is provided;

[0024] Figure 3 The single-acting hydraulic return principle diagram is provided;

[0025] Figure 4 The double-acting hydraulic output function A position principle diagram is provided;

[0026] Figure 5 The double-acting hydraulic output function B position principle diagram is provided;

[0027] Figure 6 The lowering speed adjustment function and the oil cylinder position locking function principle diagram are provided;

[0028] Figure 7 The strong pressure function conversion principle diagram is provided;

[0029] Marked in the figure: 1, hydraulic oil tank, 2, oil filter, 3, hydraulic oil pump, 4, multi-way valve assembly, 4.1, first multi-way valve, 4.2, second multi-way valve, 4.3, single double-acting switch valve I, 4.4, single double-acting switch valve II, 4.5, safety valve, 4.6, check valve, 4.7, oil return oil way, 5.1, quick change connector I, 5.2, quick change connector II, 5.3, quick change connector III, 6, oil cylinder, 7, speed regulating valve assembly, 7.1, falling speed regulating valve. DETAILED DESCRIPTION

[0030] The application will be described in detail below through exemplary embodiments. However, it should be understood that the elements, structures and features in one embodiment can be beneficially combined into other embodiments without further description.

[0031] It should be noted that, unless otherwise defined, the technical terms or scientific terms used herein should be understood as the general meaning understood by those skilled in the art to which the application belongs. The "one", "a" or "the" and similar words used in the patent application description and claims of the present application do not represent quantity limitation, but indicate the existence of at least one. The "including" or "containing" and similar words indicate that the elements or objects appearing before "including" or "containing" cover the elements or objects listed after "including" or "containing" and their equivalents, but do not exclude other elements or objects with the same function.

[0032] As shown in Figure 1 The present scheme discloses a tractor multifunctional hydraulic system, comprising a hydraulic oil tank 1, an oil filter 2, a hydraulic oil pump 3, a multi-way valve assembly 4, a speed regulating valve assembly 7 and an oil cylinder 6. The inlet end of the hydraulic oil pump 3 is communicated with the hydraulic oil tank 1 through the oil filter 2, and the outlet end of the hydraulic oil pump 3 is communicated with the main oil way and the control oil way of the multi-way valve assembly 4 respectively. The multi-way valve assembly 4 is connected with the oil chambers of the two oil cylinders 6 through the speed regulating valve assembly 7, for supplying oil to the oil cylinder 6 and controlling the falling speed of the oil cylinder 6 through the speed regulating valve assembly 7. The present scheme connects the multi-way valve assembly 4 to the hydraulic system, and the falling speed regulating valve 7 is installed between the oil cylinder 6 and the multi-way valve assembly 4. The single double-acting switch valve I 4.3 is connected with the upper chamber of the oil cylinder 6, and the falling speed regulating valve 7.1 is connected with the lower chamber of the oil cylinder 6. In the present scheme, the upper chamber of the oil cylinder 6 is the rod chamber, and the lower chamber is the rodless chamber, which further considers the simplification of the pipeline on the basis of ensuring the conversion function of strong pressure-non strong pressure. The single double-acting switch valve I 4.3 is integrated into the multi-way valve assembly 4, one end of the single double-acting switch valve I 4.3 is communicated with the upper chamber of the oil cylinder 6, and the other end is communicated with the hydraulic oil tank 1. Through the opening and closing of the single double-acting switch valve I 4.3, the conversion of strong pressure-non strong pressure can be realized, and the pipeline of the strong pressure lifting device is greatly simplified.

[0033] In the scheme, the multi-way valve assembly 4 includes a first multi-way valve 4.1, a second multi-way valve 4.2, a single-double acting switch valve I 4.3, a single-double acting switch valve II 4.4, a safety valve 4.5 and a check valve 4.6. The main oil circuit of the multi-way valve assembly 4 is connected to the oil port C1 of the first multi-way valve 4.1 and the oil port C2 of the second multi-way valve 4.2 through the check valve 4.6 respectively. The oil port D1 of the first multi-way valve 4.1 and the oil port D2 of the second multi-way valve 4.2 are connected to the return oil circuit in the multi-way valve assembly 4. The oil port E1 of the first multi-way valve 4.1 is divided into two branches through the oil circuit outlet. One branch is connected to the quick coupler I 5.1, and the other branch is connected to the lowering speed regulating valve 7.1. The lowering speed regulating valve 7.1 is connected to the rodless cavity of the two oil cylinders 6 through two branches respectively. The rod cavity of the oil cylinder 6 is connected to the oil port F1 of the first multi-way valve 4.1 through the oil circuit in the speed regulating valve assembly 7. The single-double acting switch valve I 4.3 is integrated on the pipeline at the oil port F1. The two ends of the single-double acting switch valve I 4.3 are connected to the oil port F1 of the first multi-way valve 4.1 and the return oil circuit 4.7 in the multi-way valve assembly 4 respectively. Integrating the single-double acting switch valve I 4.3 into the multi-way valve assembly 4 can greatly simplify the pipeline of the high-pressure lifting device. The switching between high pressure and non-high pressure is realized by adjusting the single-double acting switch valve I 4.3. The safety valve 4.5 is integrated in the multi-way valve assembly 4 and used as a system safety valve.

[0034] In the scheme, the multi-way valve assembly 4 controls the rising and falling of the oil cylinder 6. The lowering speed regulating valve 7.1 can realize the adjustment of the falling speed of the oil cylinder 6 and the position locking of the oil cylinder 6. The first multi-way valve 4.1 and the lowering speed regulating valve 7.1 can realize single-acting hydraulic output. The second multi-way valve 4.2 can realize double-acting hydraulic output by cutting off the single-double acting switch valve II 4.4. The conversion from hydraulic double-acting output to hydraulic single-acting output can be realized by opening the single-double acting switch valve II 4.4. The switching between high pressure and non-high pressure can be realized by adjusting the single-double acting switch valve I 4.3.

[0035] As shown in Figure 2 and 3 , the single-acting output function of the hydraulic system is realized by the following operation: when the lowering speed regulating valve 7.1 is operated to "lock" the oil circuit to the oil cylinder 6, the high-pressure hydraulic oil is no longer input to the oil cylinder 6. At this time, the first multi-way valve 4.1 is operated to the lifting position, and the high-pressure hydraulic oil is output to the outside of the system through the quick coupler 5.1, realizing the single-acting output function. The first multi-way valve 4.1 is operated to the lowering position, and the hydraulic oil flows back to the first multi-way valve 4.1 from the quick coupler I 5.1, and then back to the hydraulic oil tank 1, realizing the single-acting backflow function.

[0036] The oil port D2 of the second multi-way valve 4.2 is connected with the oil return pipeline 4.7 in the multi-way valve assembly 4, the oil port E2 is connected with the quick connector II 5.2, and the oil port F2 is connected with the quick connector III 5.3. The second multi-way valve 4.2 is integrated with a single / double action switching valve II 4.4. The first end of the single / double action switching valve II 4.4 is in communication with the pipeline between the oil port F2 of the second multi-way valve 4.2 and the quick connector III 5.3. The second end of the single / double action switching valve II 4.4 is in communication with the oil return pipeline 4.7 of the multi-way valve assembly 4.

[0037] As shown in Figure 4 and 5 , the second multi-way valve 4.2 has a working position A and a working position B. When the single / double action switching valve II 4.4 is operated to the cut-off state, the pipeline is not in communication. When the second multi-way valve 4.2 is operated to the position A, the high-pressure hydraulic oil flows from the second multi-way valve 4.2 to the quick connector II 5.2 and is outputted externally. Another route of oil is inputted from the quick connector III 5.3, flows through the second multi-way valve 4.2, and is returned to the hydraulic oil tank 1. When the second multi-way valve 4.2 is operated to the position B, the high-pressure hydraulic oil flows from the second multi-way valve 4.2 to the quick connector III 5.3 and is outputted externally. Another route of oil is inputted from the quick connector II 5.2, flows through the second multi-way valve 4.2, and is returned to the hydraulic oil tank 1. The above method realizes the double action output of the hydraulic system.

[0038] As shown in Figure 4 and 5 , the conversion function from the double action hydraulic output to the single action hydraulic output is realized by the following operation. When the single / double action switching valve II 4.4 is operated to the communication state, the pipeline in which the quick connector III 5.3 is located is in communication with the hydraulic oil tank 1. When the second multi-way valve 4.2 is operated to the position A as shown in Figure 4 , the hydraulic oil flows through the second multi-way valve 4.2, passes through the quick connector II 5.2, and is outputted to the system externally. When the second multi-way valve 4.2 is operated to the position B as shown in Figure 5 , the hydraulic oil flows back to the second multi-way valve 4.2 through the quick connector II 5.2. This method describes the single action hydraulic output function at the quick connector II 5.2.

[0039] As shown in Figure 6 , the lowering speed regulating valve 7.1 is connected with the lower cavity of the oil cylinder 6. By operating the lowering speed regulating valve 7.1, the flow rate of the oil circuit can be controlled, thereby realizing the lowering speed regulating function. When the lowering speed regulating valve 7.1 is operated to the flow rate of 0 of the oil circuit, the oil return circuit of the lower cavity of the oil cylinder 6 is cut off. At this time, the position of the oil cylinder 6 is locked, thereby realizing the position “locking” function of the oil cylinder 6.

[0040] In this scheme, refer to Figure 7When the single / double-acting switch valve I 4.3 is operated to the cut-off state, the oil passage where the single / double-acting switch valve I 4.3 is located is not connected. The high-pressure hydraulic oil is input from the first multi-way valve 4.1 to the upper chamber of the oil cylinder 6, so that the strong pressure function of the lifting device is realized. When the single / double-acting switch valve I 4.3 is operated to the connected state, the upper chamber of the oil cylinder 6 is connected to the hydraulic oil tank 1 through the single / double-acting switch valve I 4.3. When the high-pressure hydraulic oil is input from the first multi-way valve 4.1 to the upper chamber of the oil cylinder 6, the oil passage where the single / double-acting switch valve I 4.3 is located is unloaded, so that the strong pressure function of the lifting device is lost, thereby realizing the conversion between the strong pressure function and the non-strong pressure function.

[0041] The scheme also provides a control method of the multi-functional hydraulic system of the tractor. The speed regulating valve assembly 7 and the multi-way valve assembly 4 are jointly controlled or independently controlled according to different conditions, and the specific control method is as follows.

[0042] S1, strong pressure switching step: the single / double-acting switch valve I 4.3 is cut off, the high-pressure hydraulic oil is input from the first multi-way valve 4.1 to the rod chamber of the oil cylinder 6, so that the strong pressure operation of the lifting device is realized. In the strong pressure operation mode, the first multi-way valve 4.1 is controlled to the lifting position, the high-pressure hydraulic oil is input into the rodless chamber of the oil cylinder 6 through the first multi-way valve 4.1 and the lowering speed regulating valve 7.1, the hydraulic oil in the rod chamber of the oil cylinder 6 is returned to the hydraulic oil tank 1 through the first multi-way valve 4.1, the first multi-way valve 4.1 is controlled to the lowering position, the high-pressure hydraulic oil is input into the rod chamber of the oil cylinder 6 through the first multi-way valve 4.1, and the hydraulic oil in the rodless chamber of the oil cylinder 6 is returned to the hydraulic oil tank 1 through the lowering speed regulating valve 7.1;

[0043] The single / double-acting switch valve I 4.3 is opened, the rod chamber of the oil cylinder 6 is connected to the hydraulic oil tank 1 through the single / double-acting switch valve I 4.3, the high-pressure hydraulic oil is input from the first multi-way valve 4.1 to the rod chamber of the oil cylinder 6, and the oil passage where the single / double-acting switch valve I 4.3 is located is unloaded, so that the non-strong pressure operation of the lifting device is realized.

[0044] S2, lowering speed regulating step: when the oil cylinder 6 is lowered, the opening degree of the lowering speed regulating valve 7.1 is adjusted, so that the oil flow in the pipeline where the lowering speed regulating valve 7.1 is located can be controlled, thereby realizing the lowering speed regulation of the oil cylinder 6. When the oil flow through the lowering speed regulating valve 7.1 is 0, the pipeline where the lowering speed regulating valve 7.1 is located is cut off.

[0045] S3, single-acting output step: after the lowering speed regulating valve 7.1 is cut off, the oil passage between the oil cylinder 6 and the first multi-way valve 4.1 is cut off, the first multi-way valve 4.1 is controlled to the lifting position, the high-pressure hydraulic oil is output to the outside of the system through the quick-change joint I 5.1 to realize the single-acting output, the first multi-way valve 4.1 is controlled to the lowering position, the hydraulic oil returned from the outside of the system flows to the hydraulic oil tank 1 through the quick-change joint I 5.1 and the first multi-way valve 4.1 to realize the single-acting return.

[0046] S4, double-acting output step: control the single-double acting switch valve II 4.4 to the cut-off state, the second multi-way valve 4.2 realizes double-acting output, the second multi-way valve 4.2 has a working position A and a working position B, control the second multi-way valve 4.2 to the working position A, high-pressure hydraulic oil flows from the second multi-way valve 4.2 to the outside of the system through the quick-change joint II 5.2, and another hydraulic oil is input through the quick-change joint III 5.3 and returns to the hydraulic oil tank 1 after passing through the second multi-way valve 4.2, control the second multi-way valve 4.2 to the working position B, high-pressure hydraulic oil flows from the second multi-way valve 4.2 to the outside of the system through the quick-change joint III 5.3, and another hydraulic oil is input through the quick-change joint II 5.2 and returns to the hydraulic oil tank 1 after passing through the second multi-way valve 4.2;

[0047] S5, single-acting switching step: control the single-double acting switch valve II 4.4 to the connected state, the pipeline where the quick-change joint III 5.3 is located is communicated with the hydraulic oil tank 1, control the second multi-way valve 4.2 to the working position A, high-pressure hydraulic oil flows from the second multi-way valve 4.2 to the outside of the system through the quick-change joint II 5.2; control the second multi-way valve 4.2 to the working position B, hydraulic oil flows from the outside of the system through the quick-change joint II 5.2 and returns to the hydraulic oil tank 1 after passing through the second multi-way valve 4.2.

[0048] In this embodiment, the control process of the hydraulic system is optimized, the hydraulic system structure is designed, different valves are switched to realize the conversion between multiple functions, the sequence of the hydraulic control process under different working conditions is adjusted, the control steps and valve switching are more reasonable, the pipeline of the hydraulic system is simplified, and the operation convenience and reliability are improved.

[0049] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent change and modification of the above embodiment based on the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A multifunctional hydraulic system for a tractor, comprising a hydraulic oil tank, a multi-way valve assembly, a speed regulating valve assembly, and an oil cylinder, characterized in that: The speed regulating valve assembly includes a descending speed regulating valve for adjusting the descending speed of the oil cylinder, and the multi-way valve assembly includes a first multi-way valve, and the first multi-way valve includes a lifting position and a descending position; The oil port E1 of the first multi-way valve is divided into two branches, one of which is connected to the quick-change connector I, and the other is connected to the descending speed regulating valve. The descending speed regulating valve is connected to the rodless chambers of the two cylinders through the two branches respectively; The upper oil port of the oil cylinder is connected to two branches, of which the first branch is connected to the upper oil port of the first multi-way valve, and the second branch is connected to the hydraulic oil tank through a single-acting or double-acting switching valve I. The single-acting or double-acting switching valve I is integrated into the multi-way valve assembly; the single-acting or double-acting switching valve I is used to switch between high-pressure operation modes; When the descending speed regulating valve is opened, the first multi-way valve is controlled to the lifting position, and the high-pressure hydraulic oil is input into the rodless cavity of the oil cylinder through the first multi-way valve and the descending speed regulating valve; the hydraulic oil in the rod cavity of the oil cylinder flows back to the hydraulic oil tank through the first multi-way valve, and the first multi-way valve is controlled to the descending position, and the high-pressure hydraulic oil is input into the rod cavity of the oil cylinder through the first multi-way valve, and the hydraulic oil in the rodless cavity of the oil cylinder flows back to the hydraulic oil tank through the descending speed regulating valve. The flow of the oil circuit can be controlled by manipulating the descending speed regulating valve; When the descending speed regulating valve is cut off, the oil circuit between the oil cylinder and the first multi-way valve is cut off, the first multi-way valve is controlled to the lifting position, and the high-pressure hydraulic oil is output to the outside of the system through the quick-change joint I to achieve single-action output; the first multi-way valve is controlled to the descending position, and the hydraulic oil returning from the system flows into the hydraulic oil tank through the quick-change joint I and the first multi-way valve.

2. A multifunctional hydraulic system for tractors according to claim 1, characterized in that: It also includes a hydraulic oil pump and an oil filter. The inlet end of the hydraulic oil pump is connected to the hydraulic oil tank through the oil filter, and the outlet end of the hydraulic oil pump is connected to the oil circuit of the multi-way valve assembly.

3. The multifunctional hydraulic system for tractors according to claim 1, characterized in that: The multi-way valve assembly also includes a second multi-way valve and a single- and double-acting switching valve II. The oil supply ports of the second multi-way valve and the first multi-way valve are respectively connected to the outlet end of the hydraulic oil pump through a one-way valve. The single- and double-acting switching valve II is integrated into the multi-way valve assembly. The first end of the single- and double-acting switching valve II is connected to the first oil port of the second multi-way valve, and the second end of the single- and double-acting switching valve II is connected to the hydraulic oil tank.

4. The multifunctional hydraulic system for tractors according to claim 3, characterized in that: The first oil port of the second multi-way valve is connected to the quick-change connector II, and the second oil port of the second multi-way valve is connected to the first end of the quick-change connector III. The first end of the quick-change connector III is connected to the oil circuit between the single- and double-acting switching valve II and the second multi-way valve. By controlling the connection and disconnection of the single- and double-acting switching valve II, the second multi-way valve is controlled to switch between the double-acting output function and the single-acting output function.

5. A control method for a tractor multifunctional hydraulic system according to any one of claims 1 to 4, characterized in that: The multi-way valve assembly and the speed regulating valve assembly are controlled jointly or independently according to different situations, as follows:

1. Strong pressure switching steps: cut off the single- and double-acting switching valve I, and the high-pressure hydraulic oil is input to the rod chamber of the oil cylinder through the first multi-way valve to realize the strong pressure operation of the lifting device. In the strong pressure operation mode, the first multi-way valve is controlled to the lifting position, and the high-pressure hydraulic oil is input to the rodless chamber of the oil cylinder through the first multi-way valve and the descending speed regulating valve. The hydraulic oil in the rod chamber of the oil cylinder flows back to the hydraulic oil tank through the first multi-way valve. The first multi-way valve is controlled to the descending position, and the high-pressure hydraulic oil is input to the rod chamber of the oil cylinder through the first multi-way valve. The hydraulic oil in the rodless chamber of the oil cylinder flows back to the hydraulic oil tank through the descending speed regulating valve. Open the single / double-acting switching valve I, and the rod chamber of the oil cylinder is connected to the hydraulic oil tank through the single / double-acting switching valve I. High-pressure hydraulic oil is input to the rod chamber of the oil cylinder through the first multi-way valve, and the oil is unloaded from the oil circuit where the single / double-acting switching valve I is located, thus realizing the non-forced operation of the lifting device; 2. Lowering speed adjustment steps: When the oil cylinder is lowered, the oil flow in the pipeline where the lowering speed regulating valve is located can be controlled by adjusting the opening degree of the lowering speed regulating valve to achieve the lowering speed adjustment of the oil cylinder. When the oil flow through the lowering speed regulating valve is 0, the pipeline where the lowering speed regulating valve is located is cut off; 3. Single-acting output steps: When the descending speed regulating valve is cut off, the oil circuit between the oil cylinder and the first multi-way valve is cut off, the first multi-way valve is controlled to the lifting position, and the high-pressure hydraulic oil is discharged to the outside of the system through the quick-change joint I to realize single-acting output; the first multi-way valve is controlled to the descending position, and the hydraulic oil returning from the outside of the system flows through the quick-change joint I and the first multi-way valve to the hydraulic oil tank to realize single-acting return; 4. Double-acting output step: Control the single-acting and double-acting switching valve II to the cut-off state, and the second multi-way valve realizes double-acting output. The second multi-way valve has a working position A and a working position B. Control the second multi-way valve to the working position A, and the high-pressure hydraulic oil flows from the second multi-way valve through the quick-change joint II to the outside of the system, and the other hydraulic oil is input through the quick-change joint III and then flows back to the hydraulic oil tank after passing through the second multi-way valve. Control the second multi-way valve to the working position B, and the high-pressure hydraulic oil flows from the second multi-way valve through the quick-change joint III to the outside of the system, and the other hydraulic oil is input through the quick-change joint II and then flows back to the hydraulic oil tank after passing through the second multi-way valve; 5. Single-acting switching steps: Control the single-acting and double-acting switching valve II to the connected state, the pipeline where the quick-change connector III is located is connected to the hydraulic oil tank, control the second multi-way valve to the working position A, and the high-pressure hydraulic oil flows from the second multi-way valve through the quick-change connector II to the outside of the system; control the second multi-way valve to the working position B, and the hydraulic oil flows from the outside of the system through the quick-change connector II and returns to the hydraulic oil tank through the second multi-way valve.

6. The control method of a tractor multifunctional hydraulic system according to claim 5, characterized in that: In the high-pressure switching step, in the high-pressure operation mode, the first multi-way valve is controlled to the lifting position, and the high-pressure hydraulic oil is input into the lower chamber of the oil cylinder through the first multi-way valve and the descending speed regulating valve, and the hydraulic oil in the upper chamber of the oil cylinder is returned to the hydraulic oil tank through the first multi-way valve. The first multi-way valve is controlled to the descending position, and the high-pressure hydraulic oil is input into the upper chamber of the oil cylinder through the first multi-way valve, and the hydraulic oil in the lower chamber of the oil cylinder is returned to the hydraulic oil tank through the descending speed regulating valve.

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