Threaded plug type adjustable relief valve

Abstract

The utility model relates to a kind of thread plug-in adjustable type buffer pressure reducing valve, comprising: main valve sleeve has pressure oil import and pressure oil export;Main valve core is installed in main valve sleeve;Main valve spring is sleeved on main valve core;Valve body has oil drain, and lower end installs main valve sleeve;Pilot valve core is installed in main valve sleeve and valve body, and hollow passage is equipped in front end with spring seat, and rear end is equipped with pilot valve damping hole;Pilot valve sleeve is placed between pilot valve core and valve body, and radial leakage damping hole is equipped in middle part, and upper end is equipped with axial quantitative damping hole, and front end convex ring part is equipped in the lower end inner cavity of pressure regulating screw sleeve;Pilot valve spring lower end is sleeved on the spring seat of pilot valve core, and upper end is on pilot valve sleeve;Pilot cavity pressure control overflow valve is equipped in pilot valve sleeve;Pressure regulating screw sleeve and valve body are connected in screw thread cooperation, and lower end connects pilot valve sleeve, by rotating pressure regulating screw sleeve, the compression amount of pilot spring is changed, so the pressure setting value of pressure reducing valve is changed, to meet different work requirements.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic valve technology, specifically to a threaded cartridge adjustable buffer pressure reducing valve, which can be applied to the gear shifting hydraulic system of construction machinery such as excavators and loaders and agricultural machinery such as tractors, and is especially suitable for scenarios where it is necessary to control the rate of pressure rise to reduce impact. Background Technology

[0002] To improve operational efficiency, reduce operator workload, and lower failure rates, current transmission shifting methods are evolving from manual shifting to electro-hydraulic power shifting. Electro-hydraulic power shift transmissions primarily employ two shifting methods: shift fork shifting and wet clutch shifting. Shift fork shifting transmissions use a shift cylinder to drive shift gears to engage and disengage, achieving gear changes. To limit the maximum pressure of the shift cylinder, a pressure-reducing valve is installed in the cylinder's oil circuit. However, traditional pressure-reducing valves, once the pressure is set, have a fixed outlet value. When the shift circuit is activated, the pressure rises too quickly, causing the shift cylinder to move rapidly with a large output force. During gear engagement, this results in significant contact force on the gear end faces, leading to problems such as impact, noise, and gear end face wear. Wet clutch shifting gearboxes use hydraulic system pressure to control the engagement or disengagement of the internal friction plates of the clutch to achieve gear shifting. If the pressure rises too quickly during the shifting process, it can cause rapid contact between the friction plates in the clutch, resulting in shifting shock and other problems. In such cases, a buffer device must be added to the hydraulic circuit, which is bulky; or an electro-hydraulic proportional pressure reducing valve can be used to control the clutch engagement pressure according to a program. However, such systems are too expensive because they use proportional valves and controllers.

[0003] In existing technologies, such as patent document CN108644434A (threaded cartridge type buffer pressure limiting valve): it only has buffering and pressure limiting functions, and achieves pressure control by adjusting the volume of the closed cavity through the movement of the valve core. It lacks pressure reduction function, and the buffering method is singular, unable to adjust the pressure rise slope, making it difficult to adapt to the pressure gradual change requirements during gear shifting. Patent document CN110259752A (threaded cartridge type pilot pressure reducing two-stage relief valve): although it has pilot pressure reduction and two-stage relief functions, it focuses on relief pressure stabilization and one-way oil replenishment, lacking a control mechanism for the pressure rise rate, and cannot achieve the slow pressure rise buffering effect required for gear shifting. Patent document CN211059119U (threaded cartridge type pilot relief valve): it optimizes the sealing structure of the pilot valve core, but its core function is relief, lacking the ability to reduce pressure and adjust the pressure rise slope, and cannot meet the hydraulic control requirements of gearbox shifting.

[0004] Therefore, there is an urgent need for a buffer pressure reducing valve that is compact, easy to install, low in cost, and can accurately control the rate of pressure rise, in order to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a threaded cartridge adjustable buffer pressure reducing valve that is compact in structure, easy to install, stable in performance and convenient to adjust, in view of the above-mentioned technical status. The output pressure after being connected to the oil circuit rises to the set pressure with a fixed slope, or the output pressure rises to the set pressure in the form of a broken line (i.e., two slopes).

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is: a threaded cartridge type adjustable buffer pressure reducing valve, comprising:

[0007] The main valve sleeve has a pressure oil inlet and a pressure oil outlet;

[0008] The main valve core is installed inside the main valve sleeve and can move axially within the main valve sleeve. It has an oil port that corresponds to the pressure oil inlet of the main valve sleeve.

[0009] The main valve spring is fitted onto the main valve core and forces the main valve core to maintain a downward movement tendency;

[0010] The valve body has an oil drain port and external threads for valve installation, with the main valve sleeve installed at its lower end;

[0011] The pilot valve core is installed in the main valve sleeve and valve body. It adopts a ball valve design, with a spring seat and hollow channel at the front end and a pilot valve damping orifice at the rear end.

[0012] The pilot valve sleeve is located between the pilot valve core and the valve body, and can move axially within the valve body. It has a radial discharge damping hole in the middle and an axial metering damping hole at the upper end. The front end protruding ring is located in the lower end cavity of the pressure regulating screw sleeve. The outer end face area of ​​the pilot valve sleeve is larger than the inner end face area. A fluid flow channel is formed between the valve body and the pilot valve sleeve.

[0013] The pilot valve spring has its lower end fitted onto the spring seat of the pilot valve core and its upper end pressing against the pilot valve sleeve, so that the pilot valve core and the pilot valve sleeve are at their maximum distance.

[0014] The pilot chamber pressure control relief valve is located inside the pilot valve sleeve and adopts a ball valve design;

[0015] The pressure adjusting screw sleeve is located at the upper end of the valve body and is threadedly connected to the valve body. The lower end is connected to the pilot valve sleeve. By rotating the pressure adjusting screw sleeve, the compression of the pilot spring is changed, thereby changing the pressure setting value of the pressure reducing valve to meet different working requirements.

[0016] Furthermore, the upper end of the main valve core has a positioning shoulder, and the area of ​​the upper pressure surface is larger than that of the lower pressure surface.

[0017] Furthermore, a damping screw is provided in the central channel of the main valve core, and the damping screw has a main damping hole in the axial direction.

[0018] Furthermore, when the main valve core moves within the valve sleeve, the flow area between the main valve core and the valve sleeve changes, thereby altering the outlet pressure of the pressure reducing valve.

[0019] Furthermore, the inner wall of the rear end of the pressure regulating screw sleeve has an inner convex shoulder, which mates with the rear end face of the front end convex ring of the pilot valve sleeve to limit the maximum movement distance of the pilot valve sleeve.

[0020] Furthermore, the outer wall of the valve body has a positioning shoulder that can stop the valve during assembly.

[0021] Furthermore, the pilot chamber pressure control relief valve includes a relief valve core and a relief valve spring, with the relief valve spring forcing the relief valve core to remain closed.

[0022] Furthermore, a buffer cavity is formed between the front end convex ring of the pilot valve sleeve and the rear end inner cavity of the pressure regulating screw sleeve, and the quantitative damping orifice connects the interior of the pilot valve sleeve and the buffer cavity.

[0023] Furthermore, the pilot valve spring includes a first-stage pilot valve spring and a second-stage pilot valve spring. The lower end of the first-stage pilot valve spring is fitted onto the spring seat of the pilot valve core, and the upper end rests against the pilot valve sleeve. The lower end of the second-stage pilot valve spring is fitted onto another spring seat of the pilot valve core, and the upper end does not contact the pilot valve sleeve in the initial state.

[0024] Furthermore, during operation, after the pilot valve sleeve moves a certain distance, it comes into contact with the second-stage pilot valve spring, which is in a free state, causing the slope of the pressure rise at the outlet of the pressure reducing valve to change, thereby altering the buffering effect.

[0025] The beneficial effects of this utility model are:

[0026] This utility model relates to a threaded cartridge type adjustable buffer pressure reducing valve, including a main valve sleeve, a pressure adjusting screw sleeve, a main valve core, a main valve spring, a pilot valve core, a pilot valve sleeve, a pilot valve spring, a pilot chamber pressure control relief valve, and related damping holes. The main valve sleeve has a first oil inlet and a second oil inlet, and several radial oil holes. The valve body is located at the upper end of the main valve sleeve and has an axially arranged third oil inlet. The main valve core is axially movable within the main valve sleeve and has several radial oil holes at the same height as the radial oil holes in the main valve sleeve. A damping screw is provided in the middle channel of the main valve core, and the damping screw has an axially formed main damping hole. The upper end of the pilot valve core has a hollow spring seat, and the lower end of the channel has a damping screw with an axially formed pilot valve damping hole. The lower end of the pilot valve spring is fitted onto the spring seat of the pilot valve core, and the upper end acts on the aforementioned pilot valve sleeve. The pilot valve sleeve has a convex ring at its front end located in the lower inner cavity of the pressure adjusting sleeve. A radial discharge damping orifice is located in the middle, and a metering damping orifice is located axially at the front end. The pilot valve sleeve can move axially within the valve body. A pilot chamber pressure control relief valve is located within the aforementioned pilot valve sleeve. The pressure adjusting sleeve has a rear inner cavity located at the front end of the sleeve. By rotating the sleeve, the position of the pilot valve sleeve can be changed, altering the compression of the pilot spring and thus changing the system pressure setpoint to meet different operating requirements. This threaded cartridge adjustable buffer pressure reducing valve has a simple and reasonable structure, low manufacturing cost, stable and reliable overall performance, and a significant and adjustable buffering effect.

[0027] Compared with the prior art, the advantages of this utility model are as follows: the main valve core, pilot valve sleeve, and pressure regulating screw sleeve work together to form a buffer chamber through the movable pilot valve sleeve. When the pressure reducing valve is working, the oil enters the buffer chamber, pushing the pilot valve sleeve and compressing the pilot valve spring, thus achieving the effect of slow pressure increase. The overall performance is reliable and stable, ensuring long-term effective use. At the same time, the structure of each component is simple and easy to form and process. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the threaded cartridge type adjustable buffer pressure reducing valve of this utility model.

[0029] Wherein: 11-Main valve sleeve; 12-First oil port; 13-Main valve core; 14-Third oil port; 15-Main valve spring; 16-Pilot valve core; 17-Pilot valve spring; 18-Pressure adjusting screw sleeve; 19-Pilot chamber pressure control relief valve; 110-Pilot valve sleeve; 111-Valve body; 112-Second oil port; a-Main valve damping orifice; b-Pilot valve damping orifice; c-Metering damping orifice; d-Drainage damping orifice;

[0030] Figure 2 In order to be in Figure 1 A schematic diagram of adding a buffer spring to the existing design;

[0031] Wherein: 21-Main valve sleeve; 22-First oil port; 23-Main valve core; 24-Third oil port; 25-Main valve spring; 26-Pilot valve core; 27-First stage pilot valve spring; 28-Second stage pilot valve spring; 29-Pressure adjusting screw sleeve; 210-Pilot chamber pressure control relief valve; 211-Pilot valve sleeve; 212-Valve body; 213-Second oil port; e-Main valve damping orifice; f-Pilot valve damping orifice; g-Metering damping orifice; h-Drainage damping orifice;

[0032] Figure 3 for Figure 1 A schematic diagram of the pressure reducing valve outlet pressure changing over time.

[0033] Figure 4 for Figure 2 A schematic diagram of the pressure reducing valve outlet pressure changing over time. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0035] like Figure 1 As shown, the threaded cartridge-type buffer pressure reducing valve in this embodiment includes a main valve sleeve 11; a first oil port (pressure oil inlet) 12; a main valve core 13; a third oil port (return oil port) 14; a main valve spring 15; a pilot valve core 16; a pilot valve spring 17; a pressure adjusting screw sleeve 18; a pilot chamber pressure control relief valve 19; a pilot valve sleeve 110; a valve body 111; a second oil port (pressure oil outlet, i.e., pressure reducing port) 112; a main valve damping orifice a; a pilot valve damping orifice b; a metering damping orifice c; and a venting damping orifice d.

[0036] The main valve sleeve 11 has a first oil port 12 and a second oil port 112, and the valve body 111 is located at the upper end of the main valve sleeve 11 and has a third oil port 14 arranged axially.

[0037] The main valve core 13 is located inside the main valve sleeve 11 and can move axially. It has an oil port that is the same as the first oil port 12 of the main valve sleeve 11. When the main valve core 13 moves, it changes the flow area of ​​the oil port between the main valve core 13 and the main valve sleeve 11. The front end has a positioning shoulder, which limits the main valve core 13. The upper pressure surface is larger than the lower pressure surface. The middle channel of the main valve core 13 is provided with a damping screw. The damping screw has a main valve damping hole a in the axial direction. The main valve spring 15 is sleeved on the main valve core 13 and forces the main valve core 13 to maintain a downward movement tendency.

[0038] The pilot valve core 16 adopts a ball valve design, with a spring seat and hollow channel at the front end and a damping screw at the rear end. The damping screw has an axially opened pilot valve damping hole b. The lower end of the pilot valve spring 17 is sleeved on the spring seat of the pilot valve core 16, and the upper end acts on the pilot valve sleeve 110, so that the pilot valve core 16 and the pilot valve sleeve 110 are in the maximum distance state. The upper end of the pilot valve sleeve 110 is provided in the lower end inner cavity of the pressure adjusting screw sleeve 18, and the middle part has a radially provided discharge damping hole d, forming a buffer cavity between the pilot valve sleeve 110 and the pressure adjusting screw sleeve 18. The outer end face of the pilot valve sleeve 110 is larger than the inner end face, forming a fluid flow channel between the valve body 111 and the pilot valve sleeve 110. Oil enters the buffer cavity, and due to the pressure at both ends, the pilot valve sleeve 110 can move axially within the valve body 111.

[0039] The pilot chamber pressure control relief valve 19 is located inside the pilot valve sleeve 110 and adopts a ball valve design. When the pilot chamber pressure control relief valve 19 is opened, the oil flows out from the return oil port 14 through the channel between the pilot valve sleeve 110 and the valve sleeve 19, ensuring that the pressure in the pilot valve spring chamber is at the set value.

[0040] The pressure regulating sleeve 18 has a rear end cavity located at the front end of the valve body 111. By rotating the sleeve, the position of the pilot valve sleeve 110 can be changed, thereby changing the preload of the pilot valve spring 17 and thus changing the system pressure setting value to meet different working requirements.

[0041] When the pressure reducing valve is working, hydraulic oil enters from the first port 12 of the main valve sleeve 11, passes through the radial hole of the main valve core 13, and flows out from the second port 112 of the main valve sleeve 11. At the same time, pressurized oil enters the upper chamber of the main valve core 13 through the main valve damping hole a, and acts on the pilot valve core 16 through the pilot valve damping hole b. When the oil pressure is less than the opening pressure of the pilot valve, the pilot valve core 16 closes, and the pressure in the upper and lower chambers of the main valve core 13 is equal. However, since the hydraulic action area at the upper end of the main valve core 13 is slightly larger than that at the lower end, and with the force of the main valve spring 15, the main valve core 13 is at its lowest position at this time. The communication area between the first port 12 and the second port 112 is the largest, and there is basically no pressure loss in the oil flow, and the inlet and outlet pressures are basically equal. When the oil pressure increases to the initial opening pressure of the pilot valve, the pilot valve opens. The oil passes through the damping hole on the damping screw in the main valve core 13 and then enters the pilot valve chamber through the pilot valve core 16. After the oil flows through the damping hole, a pressure loss occurs, causing the pressure in the upper chamber of the main valve core 13 to be less than the pressure in the lower chamber. When the force generated by this pressure difference on the main valve core 13 exceeds the spring force, the main valve core 13 moves upward, reducing the communication area between the first oil port 12 and the second oil port 112, thereby reducing the output pressure of the second oil port 112. Simultaneously, the oil in the pilot valve core 16 is divided into three paths: one path flows back to the oil tank through the pressure control relief valve 17 in the pilot valve chamber; another path flows back to the oil tank through the drain damping orifice d; and the third path enters the buffer chamber through the metering damping orifice c. Because the metering damping orifice c has a larger diameter and a smaller flow rate, the pressure at both ends is almost identical. However, the area of ​​the oil in the buffer chamber acting on the pilot valve sleeve 110 is larger than the area of ​​the oil in the pilot valve chamber acting on the pilot valve sleeve 110. The combined hydraulic pressure on the pilot valve sleeve 110 will overcome the compressive force of the pilot valve spring 17, continuing to compress the pilot valve spring 17, thereby increasing the opening pressure of the pilot valve, i.e., increasing the pressure at the outlet of the pressure reducing valve. Its output pressure curve is shown below. Figure 3 As shown. When the pilot valve sleeve 110 moves to its maximum displacement, the pilot valve opening pressure increases to the set value, and the pressure reducing valve pressure reaches the set pressure. The pilot valve sleeve 110 requires a certain amount of time to move to its maximum displacement, thus increasing the time for the pressure reducing valve pressure to rise to the set value, achieving the buffering function of the pressure reducing valve. When the pressure reducing valve inlet pressure drops to zero, the main valve, pilot valve, and pilot chamber pressure control relief valve immediately close. The oil in the pilot valve chamber and buffer chamber flows back to the oil tank through the drain damping orifice. The pilot valve sleeve 110 moves to its initial position under the compression force of the pilot valve spring 17, achieving reset. By rotating the pressure adjusting screw sleeve, the position of the pilot valve sleeve 110 can be changed, thereby changing the preload of the pilot valve spring and thus changing the system pressure setpoint to meet different operating requirements.

[0042] To further precisely achieve the desired buffering effect, this invention adds a buffer spring to the threaded cartridge adjustable buffer pressure reducing valve, such as... Figure 2As shown. This valve adds a pilot valve spring inside the pilot valve chamber of a threaded cartridge-type adjustable buffer pressure reducing valve, consisting of a first-stage pilot valve spring 27 and a second-stage pilot valve spring 28. The lower end of the first-stage pilot valve spring 27 is fitted onto the spring seat of the pilot valve core 26, and the upper end rests on the pilot valve sleeve 211. The length of the second-stage pilot valve spring 28 is less than the length of the pilot valve spring chamber, and its lower end is fitted onto another spring seat of the pilot valve core 26, while the other end does not contact the pilot valve sleeve 211. When the pressure reducing valve first operates, due to the effect of the buffer chamber, the pilot valve sleeve 211 begins to move, and this process only overcomes the force of the first-stage pilot valve spring 27. When the pilot valve sleeve 211 moves to contact the upper end of the second-stage pilot valve spring 28, the pilot valve sleeve 211 needs to overcome the forces of the two springs and continue to compress the first-stage pilot valve spring 27 and the second-stage pilot valve spring 28, changing the rate of increase of the pilot valve opening pressure, that is, changing the slope of the increase of the pressure reducing valve outlet pressure. Its output pressure curve is as follows: Figure 4 As shown.

Claims

1. A threaded cartridge type adjustable buffer pressure reducing valve, characterized in that, include: The main valve sleeve has a pressure oil inlet and a pressure oil outlet; The main valve core is installed inside the main valve sleeve and can move axially within the main valve sleeve. It has an oil port that corresponds to the pressure oil inlet of the main valve sleeve. The main valve spring is fitted onto the main valve core and forces the main valve core to maintain a downward movement tendency; The valve body has an oil drain port and external threads for valve installation, with the main valve sleeve installed at its lower end; The pilot valve core is installed in the main valve sleeve and valve body. It adopts a ball valve design, with a spring seat and hollow channel at the front end and a pilot valve damping orifice at the rear end. The pilot valve sleeve is located between the pilot valve core and the valve body, and can move axially within the valve body. It has a radial discharge damping hole in the middle and an axial metering damping hole at the upper end. The front end protruding ring is located in the lower end cavity of the pressure regulating screw sleeve. The outer end face area of ​​the pilot valve sleeve is larger than the inner end face area. A fluid flow channel is formed between the valve body and the pilot valve sleeve. The pilot valve spring has its lower end fitted onto the spring seat of the pilot valve core and its upper end pressing against the pilot valve sleeve, so that the pilot valve core and the pilot valve sleeve are at their maximum distance. The pilot chamber pressure control relief valve is located inside the pilot valve sleeve and adopts a ball valve design; The pressure adjusting screw sleeve is located at the upper end of the valve body and is threadedly connected to the valve body. The lower end is connected to the pilot valve sleeve. By rotating the pressure adjusting screw sleeve, the compression of the pilot spring is changed, thereby changing the pressure setting value of the pressure reducing valve to meet different working requirements.

2. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, The upper end of the main valve core has a positioning shoulder, and the area of ​​the upper pressure surface is larger than that of the lower pressure surface.

3. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, The main valve core has a damping screw in the middle channel, and the damping screw has a main damping hole in the axial direction.

4. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, When the main valve core moves within the valve sleeve, the flow area between the main valve core and the valve sleeve changes, thereby altering the outlet pressure of the pressure reducing valve.

5. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, The inner wall of the rear end of the pressure regulating screw sleeve has an inner convex shoulder, which mates with the rear end face of the front end convex ring of the pilot valve sleeve to limit the maximum movement distance of the pilot valve sleeve.

6. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, The outer wall of the valve body has a positioning shoulder that can stop the valve during assembly.

7. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, The pilot chamber pressure-controlled relief valve includes a relief valve core and a relief valve spring, with the relief valve spring forcing the relief valve core to remain closed.

8. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, A buffer cavity is formed between the front end convex ring of the pilot valve sleeve and the rear end inner cavity of the pressure regulating screw sleeve, and the metering damping orifice connects the interior of the pilot valve sleeve and the buffer cavity.

9. The threaded cartridge adjustable buffer pressure reducing valve according to claim 1, characterized in that, The pilot valve spring includes a first-stage pilot valve spring and a second-stage pilot valve spring. The lower end of the first-stage pilot valve spring is fitted onto the spring seat of the pilot valve core, and the upper end rests on the pilot valve sleeve. The lower end of the second-stage pilot valve spring is fitted onto another spring seat of the pilot valve core, and the upper end does not contact the pilot valve sleeve in the initial state.

10. The threaded cartridge adjustable buffer pressure reducing valve according to claim 9, characterized in that, During operation, after the pilot valve sleeve moves a certain distance, it comes into contact with the second-stage pilot valve spring, which is in a free state. This changes the slope of the pressure rise at the outlet of the pressure reducing valve, thereby altering the buffering effect.

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