Hydraulic control valve for a fork lift truck

Abstract

This utility model relates to the field of hydraulic control valve technology and discloses a hydraulic control valve for forklifts, including a directional valve, which is a three-position four-way electro-electromagnetic directional valve used to control the flow direction of hydraulic oil; a filter, which is installed inside the oil inlet of the directional valve and has a filter screen inside to filter impurities; and an inching valve, which is installed inside the oil outlet branch of the directional valve. One end of the inching valve is fixedly connected to a control rod, and the other end of the inching valve is equipped with a spring to control the hydraulic oil pressure. In this utility model, the directional valve controls the flow direction of hydraulic oil to achieve forklift forward and reverse switching. The inching valve adjusts the valve core position under the action of the control rod and the spring. The energy storage valve uses a spring to store and release energy when the pressure is high or low. The relief valve adjusts the size of the oil outlet through a linkage structure of small valve core compression or return spring three, achieving the effect of smooth pressure change and reduced shock in the hydraulic system.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control valve technology, and in particular to a hydraulic control valve used in forklifts. Background Technology

[0002] During the operation of a forklift, the hydraulic system is the core power transmission system that enables functions such as lifting and lowering goods, steering, and forward and backward movement. The hydraulic control valve, as the "central nervous system" of the hydraulic system, plays a crucial role in regulating the pressure, flow, and direction of the hydraulic oil. A hydraulic control valve used in forklifts can precisely control the flow path and pressure changes of the hydraulic oil, ensuring smooth and rapid response during loading, unloading, and steering operations. It effectively avoids shocks and vibrations caused by excessive pressure fluctuations in the hydraulic system, reduces wear on mechanical parts, and extends the forklift's service life. Simultaneously, stable hydraulic control also improves the forklift's operational safety and efficiency, enabling it to maintain good operating conditions even under complex working conditions, which is of great significance for ensuring the smooth operation of logistics handling and warehousing.

[0003] In the prior art, the hydraulic control valves used in forklifts are usually composed of simple directional valves and relief valves. The directional valve changes the flow direction of hydraulic oil by moving the valve core, thereby enabling the forklift to switch between forward and backward movements.

[0004] However, existing hydraulic control valves for forklifts have low precision in regulating system pressure, making it difficult to achieve smooth pressure changes. When the forklift starts, stops, reverses, or changes load, hydraulic shocks are prone to occur, leading to system vibration, increased component wear, and affecting the stability and safety of forklift operation. Therefore, a hydraulic control valve for forklifts is proposed to solve the above problems. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides a hydraulic control valve for forklifts, which aims to improve the problem in the prior art that hydraulic shock is prone to occur, leading to system vibration, accelerated component wear, and affecting the stability of forklift operation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A hydraulic control valve for use in a forklift includes:

[0008] A reversing valve, wherein the reversing valve is a three-position four-way solenoid reversing valve, used to control the flow direction of hydraulic oil;

[0009] A filter is installed inside the oil inlet of the directional valve, and the filter is equipped with a filter screen inside to filter impurities;

[0010] An inching valve is installed inside the oil outlet branch of the directional valve. One end of the inching valve is fixedly connected to a control rod, and the other end of the inching valve is equipped with a spring for controlling the hydraulic oil pressure.

[0011] An energy storage valve is connected to an inching valve. The energy storage valve is equipped with a spring 2 inside, which is used to store and release energy when the hydraulic oil pressure changes.

[0012] The overflow valve is installed inside the return oil circuit of the directional valve. One end of the overflow valve is equipped with a spring three for adjusting the size of the oil outlet and controlling the pressure.

[0013] A control lever, one end of which extends to the outside of the valve block and the other end is connected to the valve core of the inching valve, is used to control the position of the valve core of the inching valve.

[0014] As a further description of the above technical solution:

[0015] The reversing valve has four oil ports: P, A, B, and T. Ports A, B, and T are in a connected state. Port A and Port B are connected through the internal oil circuit of the reversing valve. Port T, together with Ports A and B, forms a return oil passage, realizing the function of connecting specific oil circuits.

[0016] As a further description of the above technical solution:

[0017] The other end of the overflow valve is equipped with a small valve core with an oil groove.

[0018] As a further description of the above technical solution:

[0019] An overflow valve sleeve is provided on the valve core of the inching valve, and a short spring is provided on the valve core of the inching valve.

[0020] As a further description of the above technical solution:

[0021] The filter screen is made of metal woven mesh with a mesh diameter of 0.1-0.2mm and is nested inside the filter.

[0022] As a further description of the above technical solution:

[0023] The oil groove of the small valve core has a depth of 0.5-1mm and is located on the cylindrical side of the small valve core.

[0024] This utility model has the following beneficial effects:

[0025] In this invention, the forward and reverse switching of the forklift is achieved by controlling the flow of hydraulic oil through a reversing valve. The inching valve adjusts the position of the valve core under the action of the control lever and spring one. The energy storage valve stores and releases energy when the pressure is high or low using spring two. The relief valve adjusts the size of the oil outlet through a linkage structure of small valve core compression or reset spring three. This achieves the effect of smooth pressure change in the hydraulic system and reduces shock, solving the problem of easy hydraulic shock, which leads to system vibration, accelerated wear of components, and affects the stability of forklift operation. Attached Figure Description

[0026] Figure 1 This is a three-dimensional schematic diagram of a hydraulic control valve for use in a forklift, as proposed in this utility model.

[0027] Figure 2 This utility model provides a schematic diagram of the reversing valve structure of a hydraulic control valve used in a forklift.

[0028] Figure 3 This is a schematic diagram of the relief valve structure of a hydraulic control valve for forklifts proposed in this utility model.

[0029] Legend:

[0030] 1. Reversing valve; 2. Filter; 21. Filter screen; 3. Inching valve; 31. Spring 1; 32. Short spring; 33. Relief valve sleeve; 4. Energy storage valve; 41. Spring 2; 5. Relief valve; 51. Spring 3; 52. Small valve core; 6. Control lever. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] Reference Figures 1-3 One embodiment of this utility model provides: a hydraulic control valve for use in a forklift, comprising:

[0033] Reversing valve 1 is a three-position four-way solenoid reversing valve used to control the flow direction of hydraulic oil, thereby realizing rapid switching between different oil ports, reliably controlling the flow direction of hydraulic oil, and meeting the oil circuit switching needs of different working conditions such as forklift forward and backward.

[0034] Filter 2 is installed inside the oil inlet of the directional valve 1. Filter 2 is equipped with a filter screen 21 to filter impurities. It can efficiently filter impurities such as metal shavings and dust particles mixed in the hydraulic oil and prevent these impurities from entering the directional valve 1.

[0035] Inching valve 3 is installed inside the oil outlet branch of directional valve 1. One end of inching valve 3 is fixedly connected to control rod 6, and the other end of inching valve 3 is equipped with spring 31, which is used to control hydraulic oil pressure.

[0036] Energy storage valve 4 is connected to inching valve 3. Energy storage valve 4 is equipped with spring 2 41 inside, which is used to store and release energy when the hydraulic oil pressure changes.

[0037] The overflow valve 5 is installed inside the return oil circuit of the directional valve 1. One end of the overflow valve 5 is equipped with a spring 51, which is used to adjust the size of the oil outlet and control the pressure.

[0038] Control lever 6 extends one end to the outside of the valve block and the other end is connected to the valve core of inching valve 3. It is used to control the position of the valve core. By pushing or pulling control lever 6, the operator can directly move the valve core of inching valve 3, thereby changing the flow area of ​​the oil circuit and achieving continuous adjustment of hydraulic oil pressure. This meets the precise control requirements of power output for forklifts in scenarios such as loading and unloading goods and low-speed driving. The directional valve 1 has four oil ports: P, A, B, and T. Ports A, B, and T are in a connected state. Port B is connected to Port A through the internal oil circuit of directional valve 1. Port T, together with ports A and B, forms a return oil passage to achieve a specific oil circuit connection function. The other end of the overflow valve 5 is equipped with a small valve core 52 with an oil groove. The valve core of the inching valve 3 is equipped with an overflow valve sleeve 33. The valve core of the inching valve 3 is equipped with a short spring 32. The filter screen 21 is made of metal woven mesh with a mesh diameter of 0.1-0.2mm and is nested inside the filter 2. The oil groove depth of the small valve core 52 is 0.5-1mm and is opened on the cylindrical side of the small valve core 52.

[0039] Working principle: When using this hydraulic control valve, hydraulic oil first flows in from port P. When passing through filter 2, filter screen 21 filters impurities. When the forklift needs to move forward, the directional valve 1 actuates to make the oil flow out from port F. When it needs to move backward, it flows out from port R. The inching valve 3 controls the position of the valve core under the action of external force and spring 31 through the control rod 6. In the energy storage valve 4, when the hydraulic oil pressure is high, it will compress spring 41 to store energy. When the pressure is low, the spring will extend to release energy. When the hydraulic oil pressure is high, the relief valve 5 will compress spring 51 to the right through the small valve core 52 to reduce the oil flow port. When the pressure is normal, it will reset. Through the coordinated action of directional valve 1, inching valve 3, energy storage valve 4 and relief valve 5, the system pressure changes smoothly, reducing shocks and achieving stable and precise control of the forklift hydraulic system, ensuring smooth operation of the forklift.

[0040] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A hydraulic control valve for use in a forklift, characterized in that: include: The reversing valve (1) is a three-position four-way solenoid reversing valve used to control the flow direction of hydraulic oil. The filter (2) is installed inside the oil inlet of the reversing valve (1). The filter (2) is equipped with a filter screen (21) for filtering impurities. An inching valve (3) is installed inside the oil outlet branch of the directional valve (1). One end of the inching valve (3) is fixedly connected to a control rod (6), and the other end of the inching valve (3) is provided with a spring (31) for controlling the hydraulic oil pressure. Energy storage valve (4), which is connected to inching valve (3), and the energy storage valve (4) is equipped with spring 2 (41) inside, which is used to store and release energy when the hydraulic oil pressure changes; Overflow valve (5), the overflow valve (5) is installed inside the return oil circuit of the reversing valve (1), and one end of the overflow valve (5) is provided with a spring three (51) for adjusting the size of the oil outlet and controlling the pressure; The control lever (6) extends one end to the outside of the valve block and the other end is connected to the valve core of the inching valve (3) to control the position of the valve core of the inching valve (3).

2. The hydraulic control valve for a forklift according to claim 1, characterized in that: The reversing valve (1) has four oil ports: P, A, B, and T. Ports A, B, and T are in a connected state. Port A and Port B are connected through the oil circuit inside the reversing valve (1). Port T, together with Ports A and B, forms a return oil passage to realize the specific oil circuit connection function.

3. The hydraulic control valve for a forklift according to claim 1, characterized in that: The other end of the overflow valve (5) is provided with a small valve core (52) with an oil groove.

4. A hydraulic control valve for use in a forklift according to claim 1, characterized in that: An overflow valve sleeve (33) is provided on the valve core of the inching valve (3), and a short spring (32) is provided on the valve core of the inching valve (3).

5. A hydraulic control valve for use in a forklift according to claim 1, characterized in that: The filter screen (21) is made of metal woven mesh with a mesh diameter of 0.1-0.2 mm and is nested inside the filter (2).

6. A hydraulic control valve for use in a forklift according to claim 3, characterized in that: The oil groove of the small valve core (52) has a depth of 0.5-1mm and is located on the cylindrical side of the small valve core (52).

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