Electro-hydraulic lift valve for tractor

Abstract

An electro-hydraulic lift valve for a tractor comprises a valve body, an ascending valve, a descending valve and an unloading valve are arranged in the valve body, the ascending valve is arranged between the oil inlet end and the oil outlet end of the valve body, the descending valve is arranged between the oil outlet end and the oil return end of the valve body, and the unloading valve is arranged between the oil inlet end and the oil return end of the valve body. The oil outlet end of the rising valve is connected with the spring control end of the unloading valve, and the other control end of the unloading valve is connected with the oil inlet end of the valve body. The ascending valve and the descending valve are directly driven by the electromagnetic valve and have the advantages of being sensitive in response, high in repetition accuracy, small in hysteresis loop and the like. An adjusting gasket is arranged between the valve rod of the rising valve and the electric control end, and the requirements of different flows are met by selecting different adjusting gaskets; a valve rod of the rising valve adopts a B-type function, and locking dual protection of the agricultural implement in a static state is achieved through the structural characteristics of the one-way valve and the B-type function. The device has the advantages of accurate control, low operation labor intensity, high operation efficiency and the like.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery technology, specifically an electro-hydraulic lift valve for tractors. Background Technology

[0002] Currently, tractors with less than 140 horsepower in both domestic and international markets generally employ mechanically driven lifting and lowering mechanisms for agricultural implements. This method satisfies operational requirements to a certain extent in traditional agricultural operations, offering advantages such as simple mechanical structure, ease of maintenance, and economic efficiency, making it a very cost-effective system that meets the needs of traditional tractor users in China. However, with changing national policies, increasingly larger land parcels, and a younger tractor operator population, there is a growing demand for more precise, user-friendly, and intelligent hydraulic lifting systems for tractors. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide an electro-hydraulic lift valve for tractors that has a simple structure and good performance.

[0004] This utility model is achieved by the following technical solution: an electro-hydraulic lifting valve for tractors, comprising a valve body, wherein the valve body is provided with a lifting valve, a lowering valve and an unloading valve, the lifting valve is disposed between the oil inlet end and the oil outlet end of the valve body, the lowering valve is disposed between the oil outlet end and the oil return end of the valve body, the unloading valve is disposed between the oil inlet end and the oil return end of the valve body, the oil outlet end of the lifting valve is connected to the spring control end of the unloading valve, and the other control end of the unloading valve is connected to the oil inlet end of the valve body.

[0005] Furthermore, the oil outlet end of the rising valve is equipped with a one-way valve.

[0006] A damping resistor I is provided between the oil outlet end of the riser valve and the spring control end of the unloading valve.

[0007] The riser valve is a two-position three-way solenoid directional valve.

[0008] The rising valve includes a proportional solenoid valve, a return spring, and a main valve stem. The proportional solenoid valve and the return spring are located at both ends of the main valve stem. An adjusting shim is provided between the proportional solenoid valve and the main valve stem. The return spring is limited and fixed by a screw plug assembly.

[0009] The descending valve is a two-position two-way directional valve.

[0010] The unloading valve is a two-position two-way hydraulically controlled directional valve.

[0011] The unloading valve includes an unloading valve spring, an unloading valve stem, and a damper II. The unloading valve spring and the damper II are located at both ends of the unloading valve stem, and the damper II is limited and fixed by a screw plug assembly.

[0012] This utility model has the following advantages: The electro-hydraulic lift valve for tractors of this utility model has an upward valve and a downward valve directly driven by a solenoid valve, directly converting electrical energy into mechanical energy, which has the characteristics of sensitive response, high repeatability, and small hysteresis; an adjusting shim is provided between the valve stem and the electronic control end of the lift valve, and different flow requirements can be met by selecting different adjusting shims; the valve stem of the lift valve adopts a type B function, and through the structural characteristics of the one-way valve and the type B function, a double protection of locking is achieved when the agricultural machinery is stationary; this utility model has the advantages of precise control, low labor intensity of operation, and high operating efficiency. Attached Figure Description

[0013] The accompanying drawings, as part of this utility model, are used to provide a further understanding of the present utility model. The illustrative embodiments and descriptions of the present utility model are used to explain the present utility model, but do not constitute an undue limitation of the present utility model. Obviously, the drawings described below are merely some embodiments; those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0014] In the attached diagram:

[0015] Figure 1 This is a hydraulic schematic diagram of this utility model;

[0016] Figure 2 This is a schematic diagram of the structure of the riser valve of this utility model;

[0017] Figure 3 This is a schematic diagram of the structure of the unloading valve of this utility model.

[0018] In the diagram: 1. Valve body, 2. Rising valve, 3. Falling valve, 4. Check valve, 5. Unloading valve, 6. Damping I, 2-1. Proportional solenoid valve, 2-2. Return spring, 2-3. Adjusting shim, 2-4. Main valve stem, 2-5. Screw plug assembly, 5-1. Screw plug assembly, 5-2. Unloading valve spring, 5-3. Unloading valve stem, 5-4. Damping II.

[0019] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0021] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] like Figures 1 to 3 The electro-hydraulic lift valve for a tractor shown includes a valve body 1. The valve body 1 is provided with a lift valve 2, a lower valve 3, and an unloading valve 5. The lift valve 2 is located between the oil inlet and the oil outlet of the valve body 1. The lower valve 3 is located between the oil outlet and the oil return of the valve body 1. The unloading valve 5 is located between the oil inlet and the oil return of the valve body 1. The oil outlet of the lift valve 2 is connected to the spring control end of the unloading valve 5. The other control end of the unloading valve 5 is connected to the oil inlet of the valve body 1. This utility model discloses an electro-hydraulic lifting valve for tractors. The entire valve body integrates a lifting valve, a lowering valve, and an unloading valve. The lifting valve is connected to the P, H, and T ports of the valve body and is used to provide lifting power for the agricultural implement. The lowering valve is connected to the H and T ports of the valve body and is used to return oil when the agricultural implement is lowered. The lifting and lowering valves are used alternately for raising and lowering the agricultural implement. The unloading valve is connected to the P and T ports of the valve body. When the system does not need oil supply, the pressurized oil flows back to the hydraulic oil tank through the unloading valve. The operation of the unloading valve is controlled by two control terminals. The spring end is connected to the oil outlet of the lifting valve, and the other end is connected to the P port of the valve body. When the lifting valve is open and there is pressurized oil at the oil outlet, the unloading valve is closed under the action of the spring and the pressurized oil at the oil outlet of the lifting valve. When the lifting valve is not open and there is no pressurized oil at the oil outlet, the other end of the unloading valve is connected to the pressurized oil at the P port of the valve body, which pushes the unloading valve to overcome the spring pressure and switch position, opening the unloading valve and depressurizing the system.

[0024] like Figure 1The diagram shows an electro-hydraulic lift valve for a tractor, wherein the oil outlet of the lift valve 2 is equipped with a one-way valve 4. The main valve stem 2-4 is a type B valve stem. In this invention, a one-way valve is connected in series between the lift valve and the working oil port H to form a lock-up circuit, and the neutral position function of the lift valve adopts a type B function, achieving double protection and ensuring that the agricultural machinery is locked in a static state.

[0025] like Figure 1 The diagram illustrates an electro-hydraulic lift valve for a tractor. A damper I 6 is provided between the oil outlet of the lift valve 2 and the spring control end of the unloading valve 5. The oil outlet of the lift valve controls the control chamber of the unloading valve through the damper I, ensuring the unloading valve remains closed. This forms a lift control oil circuit for controlling the lifting of the tractor implements. When the lift valve is connected to port T, the control end of the unloading valve is also connected to port T through the damper I. Under the action of the damper I, the unloading valve smoothly switches its operating position, achieving slow system depressurization, protecting the system, and extending its service life.

[0026] like Figure 2 The diagram illustrates an electro-hydraulic lift valve for a tractor, wherein the lift valve 2 is a two-position three-way solenoid directional valve. The lift valve 2 includes a proportional solenoid valve 2-1, a return spring 2-2, and a main valve stem 2-4. The proportional solenoid valve 2-1 and the return spring 2-2 are located at opposite ends of the main valve stem 2-4. An adjusting shim 2-3 is provided between the proportional solenoid valve 2-1 and the main valve stem 2-4. The return spring 2-2 is fixed by a screw plug assembly 2-5. This utility model's lift valve includes a proportional solenoid valve, a return spring, a main valve stem, an adjusting shim, and a screw plug assembly. The proportional solenoid valve and the return spring are respectively the two control ends of the main valve stem. When the proportional solenoid valve is energized, the lift valve is open, connecting to port H through a one-way valve. The proportional solenoid valve and the main valve stem are connected by an adjusting shim; by selecting different shim specifications, different lifting speeds can be met.

[0027] like Figure 1 The diagram shows an electro-hydraulic lift valve for a tractor, wherein the lowering valve 3 is a two-position two-way reversing valve. When the solenoid valve of the lowering valve of this invention is energized, the return port connects to the T-port of the valve body, forming a lowering control oil circuit for controlling the lowering of the tractor implements.

[0028] like Figure 3The diagram illustrates an electro-hydraulic lift valve for a tractor, wherein the unloading valve 5 is a two-position, two-way hydraulically controlled directional valve. The unloading valve 5 includes an unloading valve spring 5-2, an unloading valve stem 5-3, and a damper II 5-4. The unloading valve spring 5-2 and the damper II 5-4 are located at both ends of the unloading valve stem 5-3, and the damper II 5-4 is fixed by a screw plug assembly 5-1. This utility model's unloading valve consists of a screw plug assembly, an unloading valve spring, an unloading valve stem, and damper II. The unloading valve creates a pressure difference between the inlet and outlet ports through damper II, achieving the function of unloading at the neutral position. In use, in the standby state of the entire machine, the P port and T port of the valve body form an unloading oil circuit through the unloading valve, achieving unloading of the oil circuit.

[0029] This utility model relates to an electro-hydraulic lift valve for tractors, which features electromagnetic direct drive, sensitive response, and high repeatability. Different adjusting shims can be selected to meet different flow requirements. The use of a one-way valve and a type B functional valve stem structure provides dual protection by locking the agricultural machinery when it is stationary.

[0030] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0031] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0032] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. An electro-hydraulic lift valve for a tractor, characterized in that: The valve includes a valve body (1), which contains an up valve (2), a down valve (3) and an unloading valve (5). The up valve (2) is located between the oil inlet and the oil outlet of the valve body (1). The down valve (3) is located between the oil outlet and the oil return of the valve body (1). The unloading valve (5) is located between the oil inlet and the oil return of the valve body (1). The oil outlet of the up valve (2) is connected to the spring control end of the unloading valve (5). The other control end of the unloading valve (5) is connected to the oil inlet of the valve body (1).

2. The electro-hydraulic lift valve for a tractor as described in claim 1, characterized in that: The oil outlet end of the riser valve (2) is equipped with a check valve (4).

3. The electro-hydraulic lift valve for a tractor as described in claim 1, characterized in that: A damping device I (6) is provided between the oil outlet end of the riser valve (2) and the spring control end of the unloading valve (5).

4. The electro-hydraulic lift valve for a tractor as described in claim 1, characterized in that: The rising valve (2) is a two-position three-way solenoid directional valve.

5. The electro-hydraulic lift valve for a tractor as described in claim 4, characterized in that: The rising valve (2) includes a proportional solenoid valve (2-1), a return spring (2-2), and a main valve stem (2-4). The proportional solenoid valve (2-1) and the return spring (2-2) are located at both ends of the main valve stem (2-4). An adjusting shim (2-3) is provided between the proportional solenoid valve (2-1) and the main valve stem (2-4). The return spring (2-2) is limited and fixed by a screw plug assembly (2-5).

6. The electro-hydraulic lift valve for a tractor as described in claim 1, characterized in that: The descending valve (3) is a two-position two-way directional valve.

7. The electro-hydraulic lift valve for a tractor as described in claim 1, characterized in that: The unloading valve (5) is a two-position two-way hydraulic control directional valve.

8. The electro-hydraulic lift valve for a tractor as described in claim 7, characterized in that: The unloading valve (5) includes an unloading valve spring (5-2), an unloading valve stem (5-3), and a damping II (5-4). The unloading valve spring (5-2) and the damping II (5-4) are located at both ends of the unloading valve stem (5-3). The damping II (5-4) is limited and fixed by a screw plug assembly (5-1).

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