Hydraulic steering priority valve

Abstract

The utility model relates to a hydraulic steering priority valve which comprises a valve body, a valve element, a control spring, an oil inlet, a steering control oil port, an execution loop control oil port, a load sensing oil port and an LS damping hole adjusting mechanism. A second damping hole is formed in the end, close to the load sensing oil port, of the valve element, a containing groove is formed in the position, located on a communication path between the load sensing oil port and the oil cavity, in the valve body, the LS damping hole adjusting mechanism comprises a moving block and a driving device, and the driving device controls the moving block to slide in the containing groove. The load sensing oil port can be communicated with the oil cavity through LS damping holes with different hole diameters. The hydraulic steering priority valve has the advantages that the problem that a valve body needs to be detached for adjustment of an LS damping hole in an existing hydraulic steering priority valve is solved, and the purpose of rapidly adjusting the aperture of the LS damping hole in real time without detachment is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of hydraulic control, and in particular relates to a hydraulic steering priority valve. Background Art

[0002] The steering system of construction machinery, a key component of its hydraulic system, has a decisive impact on the overall machine's handling performance. Within the steering system, the priority valve dynamically prioritizes flow to the steering circuit based on steering speed requirements. Therefore, the hydraulic steering priority valve is a core component of the steering system. The priority valve primarily consists of a valve body, a valve core, and a control spring. The valve body features an oil inlet (P), a steering control port (CF), an actuator control port (EF), and a load-sensing port (LS). These ports communicate with the oil chambers within the valve body, and the valve core and control spring facilitate serial connection between the ports. In practice, construction machinery and agricultural machinery face highly variable operating environments, such as those involving heavy and light loads, high and low temperatures, and other extreme conditions. These conditions can cause significant fluctuations in the hydraulic system's flow demand. To achieve optimal steering flow matching, the diameter of the load-sensing (LS) damping orifice is often adjusted. However, existing priority valve designs utilize a fixed damping plug for the LS damping orifice. Despite its simple structure, this design presents significant practical drawbacks: adjusting the LS damping orifice diameter requires disassembling the valve body and replacing the damping plug with the appropriate diameter. This tedious and complex process requires equipment downtime of one to two hours, resulting in project delays and reduced operational efficiency. Furthermore, frequent valve disassembly increases the risk of hydraulic system seal failure, posing a potential threat to system reliability and stability.

[0003] In view of this, it is particularly necessary to design a hydraulic steering priority valve structure that can adjust the LS damping orifice diameter in real time without disassembly, so as to meet the needs of modern engineering machinery and agricultural machinery for efficient and flexible hydraulic control. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings of the existing technology and provide a hydraulic steering priority valve, which can solve the problem that the LS damping hole adjustment in the existing hydraulic steering priority valve requires the disassembly of the valve body, and achieve the purpose of disassembly-free and real-time rapid adjustment of the LS damping hole aperture.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] A hydraulic steering priority valve comprises a valve body, a valve core, a control spring, an oil inlet, a steering control oil port, an execution circuit control oil port, and a load sensing oil port. An oil chamber is provided in the valve body, and the valve core and the control spring are arranged in the oil chamber. The valve body also comprises an LS damping hole adjustment mechanism, an oil distribution channel is provided in the valve core, a first damping hole is provided on one end of the valve core close to the oil inlet, and a second damping hole is provided on one end of the valve core close to the load sensing oil port. The oil distribution channel is connected to the oil chamber through the first damping hole and the second damping hole. One end of the control spring is connected to one end of the valve core with the second damping hole, and the other end of the control spring is connected to the oil chamber. The end is fixedly connected to the inner wall of the oil chamber, and a receiving groove is provided in the valve body at the communication path between the load sensing oil port and the oil chamber. The LS damping hole adjustment mechanism includes a moving block and a driving device. One end of the moving block is slidably arranged in the receiving groove and blocks the load sensing oil port and the oil chamber. The other end of the moving block extends out of the valve body and is connected to the driving device. The end of the moving block located in the receiving groove is provided with multiple LS damping holes with different apertures in sequence along the moving direction of the moving block. When the driving device controls the moving block to slide in the receiving groove, the load sensing oil port can be connected to the oil chamber through LS damping holes with different apertures.

[0007] Furthermore, the driving device is a micro cylinder, the micro cylinder is arranged on the valve body, and the driving shaft of the micro cylinder is connected to the moving block.

[0008] Furthermore, four LS damping holes are provided, and the apertures of the four LS damping holes are 0.8 mm, 1.0 mm, 1.2 mm, and 1.4 mm, respectively.

[0009] Furthermore, a dynamic seal is provided between the accommodating groove and the moving block.

[0010] Furthermore, a clamp mechanism for locking and positioning the moving block is provided on the outer wall of the valve body at the accommodating groove.

[0011] Furthermore, a guide groove is provided on the outer wall of the valve body, and the clamp mechanism includes two butted jackets, which are connected by locking bolts, and the two jackets are provided with sliders which are slidably connected to the guide groove.

[0012] Furthermore, a detachable observation and maintenance window is provided on the outer wall of the valve body at the accommodating groove.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The utility model controls the LS damping orifice adjustment mechanism. According to actual needs, under steady-state working conditions, the driving device is used to push the moving block to move back and forth in the accommodating groove to realize the switching of LS damping orifices with different apertures. Then, in combination with the cooperation of the valve core and the control spring, when oil is fed into the oil inlet, the oil will enter the load sensing oil port through the oil chamber, the first damping orifice, the oil distribution channel, the second damping orifice, and the LS damping orifice, thereby realizing real-time and rapid adjustment of the LS damping orifice aperture without disassembling the valve body, avoiding the tedious steps of disassembling the valve body when replacing the damping plug of the traditional priority valve, effectively shortening the downtime and improving the working efficiency.

[0015] 2. Based on system simulation results, the utility model precisely controls the apertures of the four LS damping orifices to 0.8mm, 1.0mm, 1.2mm, and 1.4mm, effectively adapting to flow requirements under different operating conditions. Combined with the optimized coordination of the valve core and control spring, the system achieves optimal steering flow and steering valve pressure differential under various operating conditions. Furthermore, the coordinated operation of the steering control oil port and the actuator circuit control oil port further ensures stable operation and rapid response of the steering system, thus meeting flow requirements under different operating conditions.

[0016] 3. This utility model uses a preset micro-cylinder stroke to ensure the precise forward and backward movement of the moving block, ensuring that each LS damping orifice precisely aligns with the oil chamber and load-sensing port, forming a connecting channel. Furthermore, a clamping mechanism secures the moving block, effectively preventing displacement deviations caused by vibrations from the construction machinery, thereby improving the stability and accuracy of the overall system.

[0017] 4. This utility model features a removable inspection window, allowing the operator to visually confirm the current position of the moving block and which aperture marker is aligned with the oil passageway, thereby verifying proper switching (aperture markers are engraved on the moving block corresponding to each LS damping orifice). If not, adjustments can be made using a micro-cylinder, or the inspection window and micro-cylinder can be removed for manual inspection and adjustment. This, combined with the micro-cylinder's preset distance control, ensures accurate switching of the LS damping orifices. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of the hydraulic steering priority valve in the utility model;

[0019] Figure 2 for Figure 1 A magnified schematic diagram of the structure at A;

[0020] Figure 3 Schematic diagram of simulation results of the change of steering flow affected by LS damping holes of different apertures in the present invention;

[0021] Figure 4 Schematic diagram of simulation results of the change of the steering valve pressure difference affected by LS damping holes of different apertures in the present invention;

[0022] Figure 5 This is another overall structural diagram of the hydraulic steering priority valve in the present utility model;

[0023] Figure 6 for Figure 5 Schematic diagram of the coordination between the middle clamp mechanism and the moving block;

[0024] Figure 7 This is a schematic diagram of the installation of the observation and inspection window in the present utility model.

[0025] In the figure: 1. Valve body; 2. Valve core; 3. Control spring; 4. Oil inlet; 5. Steering control oil port; 6. First damping hole; 7. Second damping hole; 8. Transition section; 9. Execution circuit control oil port; 10. Receiving groove; 11. Moving block; 12. Driving device; 13. Load sensing oil port; 14. Dynamic seal; 15. Clamp mechanism; 16. Slider; 17. Guide slide; 18. Observation and maintenance window. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description. Example 1

[0027] like Figure 1 As shown, a hydraulic steering priority valve has a main structure including a valve body 1, a valve core 2, a control spring 3, an oil inlet 4, a steering control oil port 5, an actuator circuit control oil port 9, and a load sensing oil port 13. An oil chamber is defined within the valve body 1, and the valve core 2 and control spring 3 are disposed within the oil chamber.

[0028] An oil chamber is machined into the valve body 1. The oil inlet 4 (P port), steering control port 5 (CF port), actuator control port 9 (EF port), and load sensing port 13 (LS port) are all connected to the oil chamber. The oil inlet 4 and steering control port 5 are located at one end of the oil chamber, while the actuator control port 9 and load sensing port 13 are located at the other end. A transition section 8 is provided in the middle of the oil chamber. The valve core 2 is assembled within the oil chamber. An oil distribution channel is provided within the valve core 2. A first damping orifice 6 is provided on the end of the valve core 2 near the oil inlet 4, and a second damping orifice 7 is provided on the end of the valve core 2 near the load sensing port 13. The oil distribution channel communicates with the oil chamber through the first and second damping orifices 6 and 7. One end of the control spring 3 is connected to the end of the valve core 2 where the second damping orifice 7 is located. The other end of the control spring 3 is fixed to the inner wall of the oil chamber. On the basis of the oil pressure difference at both ends of the oil chamber, the valve core 2 is pushed back and forth in the oil chamber in combination with the expansion and contraction of the control spring 3, thereby realizing the connection state between the control oil inlet 4, the steering control oil port 5, the execution circuit control oil port 9, the load sensing oil port 13 and the oil chamber.

[0029] In order to achieve the function of real-time and rapid adjustment of the LS damping orifice diameter without disassembly and avoid the tedious operation process of disassembling the valve body when replacing the damping plug in the traditional priority valve, an LS damping orifice adjustment mechanism is provided between the load sensing oil port 13 and the oil chamber to dynamically control the connection state between the LS port and the oil chamber. Figure 1 、 Figure 2 As shown, the LS damping hole adjustment mechanism is mainly composed of three parts: the first is a moving block 11, which is provided with a receiving groove 10 on the communication path between the oil chamber and the LS port, one end of the moving block 11 is slidably arranged in the receiving groove 10 and blocks the LS port and the oil chamber, and the other end of the moving block 11 extends out of the valve body 1; the second is a plurality of LS damping holes with different apertures, and the plurality of LS damping holes are provided on one end of the moving block 11 located in the receiving groove 10 and in sequence along the moving direction of the moving block 11; the third is a driving device 12 connected to one end of the moving block 11 extending out of the valve body 1, and the driving device 12 adopts a micro cylinder, which is installed on the valve body, and the driving shaft of the micro cylinder is fixedly connected to the moving block 11, and the micro cylinder can be stably installed with the aid of some shock-absorbing brackets. Under the precise control of a micro-pneumatic cylinder, movable block 11 executes reciprocating linear motion within a preset stroke within receiving slot 10, thereby sequentially and precisely aligning LS damping orifices of varying diameters with the connecting passage between the oil chamber and the LS port. Presetting the cylinder stroke parameters ensures accurate alignment of the target damping orifice after each movement. It should be noted that alternatives to drive device 12 could also utilize a stepper motor coupled with a lead screw drive mechanism, or a manual screw fine-tuning mechanism, to similarly achieve displacement control of movable block 11.

[0030] To ensure high pressure sealing performance, such as Figure 2As shown, a dynamic seal 14 (made of high-strength polytetrafluoroethylene composite material) is installed in the gap between the receiving groove 10 and the moving block 11. When the moving block 11 slides within the receiving groove 10, the dynamic seal 14 is squeezed and deformed, forming a dynamic sealing interface, effectively isolating the oil chamber from the LS port and the risk of high-pressure oil leakage.

[0031] The working principle and process of this embodiment are mainly as follows:

[0032] by Figure 1 The shown orientation is a reference. In the initial state (no steering load), the valve core 2 is in the left extreme position under the action of the control spring 3. At this time, the oil circuit from the oil inlet 4 to the steering control oil port 5 is fully connected, while the oil circuit from the oil inlet 4 to the execution circuit control oil port 9 is in a closed state due to the obstruction of the valve core 2. The LS damping orifice is adjusted and selected through the LS damping orifice adjustment mechanism. When the system is working, if the load sensing oil port 13 does not detect the steering load signal, the pressure oil in the oil inlet 4 flows to the execution circuit control oil port 9 through the oil chamber; then, part of the oil enters the oil distribution channel through the first damping orifice 6 of the valve core 2, flows through the second damping orifice 7 and reaches the oil chamber area where the control spring 3 is located, and finally flows into the load sensing oil port 13 through the currently selected LS damping orifice. At this time, since there is no load pressure on the LS port, the oil pressure on the left end of the valve core 2 is greater than the spring force on the right end, driving the valve core 2 to move to the right. Driving the valve core 2 to move to the right causes the flow channel from the oil inlet 4 to the execution circuit control oil port 9 to gradually open, and at the same time, the flow channel from the oil inlet 4 to the steering control oil port 5 to gradually shrink, and the oil flows into the execution circuit control oil port 9 through the transition section 8. When the oil pressure and spring force at both ends of the valve core 2 reach a balance, the valve core 2 stabilizes at the right end limit position. At this time, the flow channel of the execution circuit control oil port 9 is opened to the maximum, and the flow channel of the steering control oil port 5 only maintains the minimum flow cross-section required by the LS signal; on the contrary, when the load sensing oil port 13 detects the steering load signal, the load pressure on the right end of the valve core 2 plus the spring force will exceed the oil pressure on the left end, forcing the valve core 2 to move left. During the process of the valve core 2 moving left, the flow channel of the execution circuit control oil port 9 is gradually closed, and the flow channel of the steering control oil port 5 is gradually increased, thereby ensuring that the steering system obtains priority in the supply of hydraulic oil.

[0033] To quantitatively verify the design effect of the LS damping orifice adjustment, this embodiment conducts a system simulation of the steering flow and the steering valve pressure difference for LS damping orifices of different diameters to study the impact of LS damping orifices of different diameters on the steering flow and the steering valve pressure difference. The simulation results are as follows:

[0034] In this embodiment, four LS damping holes are provided, and the apertures C of the four LS damping holes are 0.8 mm, 1.0 mm, 1.2 mm, and 1.4 mm respectively. The simulation results of the change of the steering flow Q affected by the LS damping holes of different apertures over time t are shown as follows: Figure 3As shown in the figure, the simulation results of the change of the steering valve pressure difference p affected by the LS damping holes of different apertures are shown in Figure 4 As shown in the figure, x is the horizontal coordinate, and y1~y4 are the vertical coordinates corresponding to x. Figure 3 The steering flow data corresponding to the four LS damping holes at t = x = 2.678s and Figure 4 The steering valve pressure difference data corresponding to the four LS damping holes when t is x=2.82s are shown in Table 1 below.

[0035] Table 1

[0036]

[0037] comprehensive Figure 3 、 Figure 4 As shown in Table 1, steering flow and steering valve differential pressure are highly sensitive to changes in the LS damping orifice diameter. This result fully demonstrates the significant impact of dynamic adjustment of the LS damping orifice diameter on steering response speed and system stability, confirming the rationality and engineering practicality of this embodiment. Its core value lies in enabling real-time and rapid adjustment of the LS damping orifice under disassembly-free operating conditions, effectively circumventing the traditional valve body disassembly process. Furthermore, the preset orifice combinations can cover diverse operating conditions. For example, selecting a small-diameter damping orifice (e.g., 0.8mm) for heavy-load conditions improves steering responsiveness, while selecting a large-diameter damping orifice (e.g., 1.4mm) for light-load conditions effectively reduces system energy consumption. Example 2

[0038] Based on the structure of the first embodiment, this embodiment has been specially reinforced for the vibration working conditions of engineering machinery. Specifically, in order to prevent the vibration of the priority valve from causing the moving block 11 to move unexpectedly, a clamping mechanism 15 is added to the valve body 1 to improve the long-term stability of the LS damping hole alignment. The clamping mechanism 15 is an existing structure, including two butted jackets, which are connected by high-strength locking bolts. More specifically, as Figure 5 、 Figure 6 As shown, a slider 16 is fixed to the opposite side of each jacket, and a guide slot 17 is provided on the outer wall of the valve body 1. The two sliders 16 are slidably connected to the guide slot 17. When the movable block 11 moves, the load sensing oil port 13 is connected to the oil chamber through the LS damping hole and positioned. Under the sliding cooperation of the slider 16 and the guide slot 17, the two jackets slide toward each other and embrace the movable block 11. The two sleeves are then locked and fixed by the locking bolt to hold the movable block 11, thereby preventing vibration-induced displacement deviation of the movable block. When it is necessary to switch to an LS damping hole of a different aperture, the locking bolt is opened, and the two jackets are then slid away from each other, thereby releasing the fixation of the movable block 11. Example 3

[0039] Based on the structure of the first embodiment, this embodiment adds a detachable observation and maintenance window 18 at the position of the outer wall of the valve body 1 corresponding to the receiving groove 10. Figure 7 As shown, a slot is machined on the side of the valve body 1, and the inspection window 18 is designed to be snapped into the slot from the side. The inspection window 18 can be disassembled and assembled by pushing and pulling. Through the inspection window 18, the operator can directly visually confirm the real-time position of the moving block 11. On this basis, by engraving the aperture mark corresponding to the LS damping hole (such as "Ø1.2") on the surface of the moving block 11, it can be verified whether the target LS damping hole is accurately aligned with the oil channel. If there is a deviation in the alignment, the drive device 12 can be used for fine-tuning, or the inspection window 18 and the drive device 12 can be disassembled to manually calibrate the position of the moving block 11, thereby improving maintenance convenience and adjustment accuracy.

[0040] This utility model systematically solves the problem of LS damping hole adjustment requiring shutdown and disassembly in existing hydraulic steering priority valves through the associated design of adjustable damping mechanism → vibration protection → visual maintenance. The disassembly-free adjustment feature can shorten the downtime to minutes, improving operating efficiency by more than 40%.

[0041] Finally, although the above description has shown and described the embodiments of the present invention, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic steering priority valve, comprising a valve body (1), a valve core (2), a control spring (3), an oil inlet (4), a steering control oil port (5), an execution circuit control oil port (9), and a load sensing oil port (13), wherein an oil chamber is provided in the valve body (1), and the valve core (2) and the control spring (3) are provided in the oil chamber, and characterized in that: The LS damping hole adjustment mechanism is also included. An oil distribution channel is provided in the valve core (2). A first damping hole (6) is provided at one end of the valve core (2) near the oil inlet (4). A second damping hole (7) is provided at one end of the valve core (2) near the load sensing oil port (13). The oil distribution channel is connected to the oil chamber through the first damping hole (6) and the second damping hole (7). One end of the control spring (3) is connected to one end of the valve core (2) provided with the second damping hole (7). The other end of the control spring (3) is fixed to the inner wall of the oil chamber. A receiving groove (10) is provided in the valve body (1) at the communication path between the load sensing oil port (13) and the oil chamber. The damping hole adjustment mechanism comprises a moving block (11) and a driving device (12), one end of the moving block (11) is slidably arranged in the receiving groove (10) and blocks the load sensing oil port (13) and the oil chamber, the other end of the moving block (11) extends outward from the valve body (1) and is connected to the driving device (12), and one end of the moving block (11) located in the receiving groove (10) is provided with a plurality of LS damping holes with different apertures in sequence along the moving direction of the moving block (11), and when the driving device (12) controls the moving block (11) to slide in the receiving groove (10), the load sensing oil port (13) can be communicated with the oil chamber through the LS damping holes with different apertures.

2. The hydraulic steering priority valve according to claim 1, characterized in that: The driving device (12) is a micro cylinder, which is arranged on the valve body (1), and the driving shaft of the micro cylinder is connected to the moving block (11).

3. The hydraulic steering priority valve according to claim 1, characterized in that: There are four LS damping holes, and the apertures of the four LS damping holes are 0.8 mm, 1.0 mm, 1.2 mm, and 1.4 mm respectively.

4. The hydraulic steering priority valve according to claim 1, characterized in that: A dynamic seal (14) is provided between the accommodating groove (10) and the moving block (11).

5. The hydraulic steering priority valve according to claim 1, characterized in that: The outer wall of the valve body (1) is provided with a clamp mechanism (15) located at the accommodating groove (10) for locking and positioning the moving block (11).

6. The hydraulic steering priority valve according to claim 5, characterized in that: The outer wall of the valve body (1) is provided with a guide groove (17), and the clamp mechanism (15) includes two butted jackets, the two jackets are connected by a locking bolt, and the two jackets are provided with a slider (16) slidably connected to the guide groove (17).

7. The hydraulic steering priority valve according to claim 1, characterized in that: A detachable observation and maintenance window (18) is provided on the outer wall of the valve body (1) at the receiving groove (10).

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