A high differential pressure pressure relief valve for a hydraulic control system and a method of designing the same

Abstract

The embodiment of the application discloses a high-pressure-difference constant-pressure valve for a hydraulic control system and a design method thereof, and the design method comprises the following steps: step 1, determining the stiffness of a spring used by the high-pressure-difference constant-pressure valve, determining the diameter of the spring based on the stiffness of the spring, and designing the valve and the spring seat as an integrated structure according to the determined diameter of the spring; step 2, based on the integrated structure of the valve and the spring seat, setting an anti-absorption protruding edge on the side end face of the spring seat in abutting cooperation with the valve and the spring seat, so as to reduce the contact area of the valve and the bushing in a non-working state; step 3, setting a plurality of pressure equalizing grooves on the outer wall surface of the side of the valve close to the low-pressure oil end, so as to reduce the non-axial movement phenomenon of the valve caused by the high-pressure-difference acting force; and step 4, based on the characteristics that the oil flowing through the hole of the bushing to the inner wall of the shell has a high flow rate, an annular groove is set on the inner wall of the shell in the hole region of the bushing, so as to avoid the cavitation phenomenon caused by the high-speed constant-pressure oil to the shell.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of constant pressure valve technology in hydraulic control systems, and particularly to a high pressure differential constant pressure valve for hydraulic control systems and its design method. Background Technology

[0002] Current pressure-regulating valve designs are primarily geared towards pressure differentials of 2 MPa and below, such as... Figure 1 The diagram shown is a schematic of a typical constant pressure valve assembly in the prior art. Due to the low pressure difference and flow rate, the spring stiffness is small, and the spring seat and valve are separate. The spring seat is installed at the lower end of the valve using an interference fit, making its structural design relatively simple. The constant pressure oil outlet also serves as a constant pressure feedback chamber. Furthermore, the pressure difference within the gap between the valve and the bushing is low. Within a pressure difference of less than 2 MPa, the valve in the constant pressure valve assembly is less prone to non-axial movement, which could lead to valve jamming.

[0003] With technological advancements, aero-engines are placing increasing demands on the performance of fuel accessories, leading to higher requirements for constant pressure fuel differential pressure and flow rate. This has created a need for constant pressure valves operating in environments with higher differential pressures (more than twice the differential pressure of conventional constant pressure valves) and larger flow rates. However, for constant pressure valves with high differential pressures and large flow rates, the incoming fuel pressure is often high to meet these requirements. Existing constant pressure valve structures are unsuitable for applications with high differential pressures and large flow rates, which can lead to adverse effects such as increased fuel flow velocity, larger spring volume, and non-axial valve movement. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems. This invention provides a high-pressure differential constant-pressure valve for hydraulic control systems and its design method, so as to solve the problems caused by the adverse effects of existing constant-pressure valves being unsuitable for high-pressure differential and high-flow application scenarios, such as increased fuel flow rate, large spring volume, and non-axial movement of the valve.

[0005] The technical solution of the present invention: In a first aspect, embodiments of the present invention provide a high-pressure differential pressure regulating valve for a hydraulic control system, comprising: Step 1: Based on the design requirements of the high pressure differential constant pressure valve for the constant pressure valve, determine the stiffness of the spring used in the high pressure differential constant pressure valve, determine the spring diameter based on the spring stiffness, and design the valve and spring seat as an integral structure according to the determined spring diameter. Step 2: Based on the integrated structure of the valve and the spring seat, an anti-adsorption protrusion is provided on the end face of the bushing and the valve where the spring seat abuts against each other, in order to reduce the contact area between the valve and the bushing in the non-working state. Step 3: Based on the characteristic that the high pressure differential constant pressure valve has a large pressure difference at both ends, multiple pressure equalization grooves are opened on the outer wall surface of the valve near the low pressure oil end to reduce the non-axial movement phenomenon formed by the valve under the force of high pressure differential. Step 4: Based on the high flow rate of the oil flowing from the bushing orifice to the inner wall of the housing, an annular groove is opened on the inner wall of the housing in the bushing orifice area to avoid cavitation caused by high-speed constant pressure oil to the housing.

[0006] Optionally, in the design method of the high-pressure differential pressure regulating valve for a hydraulic control system as described above, step 1 includes: Step 11: The applicable pressure difference of the high pressure differential constant pressure valve is at least twice that of the pressure difference of the conventional constant pressure valve. The spring stiffness of the determined high pressure differential constant pressure valve is greater than that of the spring stiffness in the conventional constant pressure valve, and the spring diameter is also greater than that of the conventional spring. Step 12: Based on the determined spring diameter, design the valve and spring seat of the high pressure differential pressure regulating valve as an integral structure. The spring seat is located at the low pressure oil end of the valve, and the diameter of the spring seat is larger than the determined spring diameter, so that one end of the spring is mounted against the end face of the spring seat of the integral structure.

[0007] Optionally, in the design method for a high-pressure differential pressure regulating valve for a hydraulic control system as described above, step 2 includes: Based on the integrated structure of the valve and spring seat designed in step 1, the contact area between the end face of the spring seat on the valve and the bushing is increased, which increases the probability of the valve adsorbing with the bushing before reaching the working pressure. By adding an anti-adsorption protrusion to the end face of the bushing and the spring seat on the valve, the contact area between the valve and the bushing in the non-working state is reduced, so as to avoid the valve adsorbing with the bushing before reaching the working pressure.

[0008] Optionally, in the design method of the high pressure differential constant pressure valve for the hydraulic control system described above, in step 3, multiple pressure equalization grooves opened on the outer wall of the valve are located between the two cavities with higher pressure difference on the valve; and there is a gap between the top of the multiple pressure equalization grooves on the outer wall of the valve and the bushing; so that when the high pressure differential constant pressure valve is working, the oil flows into the gap and is evenly distributed around the valve, so that the oil pressure is evenly distributed around the valve, thereby reducing the non-axial movement phenomenon formed by the high pressure differential force on the valve.

[0009] Optionally, in the design method of the high-pressure differential constant pressure valve for the hydraulic control system described above, in step 4, by creating an annular groove on the housing, an annular cavity is formed between the housing and the bushing that communicates with the upper hole of the bushing. This is equivalent to increasing the flow area of ​​the upper hole of the bushing, thereby significantly reducing the flow velocity of the constant pressure oil reaching the inner wall of the housing. This makes the constant pressure oil pressure in the annular cavity uniform, ensuring that the oil in the annular cavity is always higher than the saturated vapor pressure, thereby avoiding cavitation on the aluminum housing.

[0010] Optionally, the design method for a high-pressure differential pressure regulating valve for a hydraulic control system, as described above, further includes: Step 5: Based on the large pressure difference at both ends of the high differential pressure valve and the high stiffness of the spring used, design the pressure chamber volume and feedback nozzle at the valve's constant pressure oil end; design the pressure chamber volume according to the sensitivity requirements of the high differential pressure valve, and design the throttle nozzle according to the stability requirements of the high differential pressure valve under working conditions.

[0011] Optionally, in the design method of the high-pressure differential pressure regulating valve for the hydraulic control system described above, step 5 includes: Step 51: A recess is opened on the constant pressure oil end face of the valve to form a pressure chamber between it and the outer bushing and housing, and the volume of the pressure chamber is controlled to be small, within 1 ml. Step 52: An axial flow groove is formed at one end face of the constant pressure oil of the valve to serve as a feedback oil nozzle. The flow area of ​​the flow groove is small, less than 1% of the cross-sectional area of ​​the valve 3.

[0012] Secondly, the present invention also provides a high pressure differential pressure regulating valve for a hydraulic control system. The high pressure differential pressure regulating valve is designed using the design method for a high pressure differential pressure regulating valve for a hydraulic control system as described in any of the above claims. The high pressure differential pressure regulating valve includes: a housing 12, a valve 3, a bushing 4, a spring seat 9, a spring 10, and an end cap 13. The bushing 4 is fitted onto the valve 3, forming a high-pressure oil flow cavity with the central annular groove of the valve 3. A housing 12 is fitted over the bushing 4. The low-pressure oil end of the valve 3 is provided with an integral spring seat 9. A spring 10 fitted onto the spring seat 9 is pressed against the other end of the spring 10 by an end cap 13 screwed into the housing 12, and the end cap 13 rests against the end face of the bushing 4. The diameter of the spring 10 is at least twice the diameter of the valve 3, and is used to provide the spring force to form a high pressure differential. The bushing 4 is provided with an anti-adsorption protrusion 5 on the side face near the low-pressure oil end of the valve 3 to reduce the contact area between the valve 3 and the bushing 4 in the non-working state; multiple pressure equalization grooves are opened on the outer wall surface of the valve 3 near the low-pressure oil end to reduce the non-axial movement phenomenon formed by the valve under the action of high pressure differential force. The inner wall of the housing 12 has an annular groove in the bushing 4-type hole area, forming an annular cavity between the housing and the bushing that communicates with the upper hole of the bushing. This significantly reduces the flow rate of the constant pressure oil reaching the inner wall of the housing, making the constant pressure oil pressure in the annular cavity uniform. The bushing also has a flow hole for connecting the annular cavity and the valve constant pressure oil cavity.

[0013] The valve 3 has a concave cavity on its constant pressure oil end face, which forms a pressure chamber with the outer bushing 4 and the housing 12. The volume of the pressure chamber is small, usually less than 1 ml. A flow groove 12 is formed along the axial direction on one part of the constant pressure oil end face of the valve 3 as a feedback oil nozzle. The flow area of ​​the flow groove 12 is small, less than 1% of the cross-sectional area of ​​the valve 3.

[0014] The beneficial effects of this invention: This invention provides a high-pressure differential constant-pressure valve for hydraulic control systems and its design method. Specifically, it proposes a structural design solution to address the adverse effects of existing constant-pressure valves being unsuitable for high-pressure differential, high-flow-rate applications, such as increased fuel flow rate, large spring volume, and non-axial valve movement. The design solution provided by this invention has the following beneficial effects: First, by designing the valve and the spring seat for the retaining spring as an integrated structure, the design problem caused by the exponential increase in spring diameter due to the requirement for high stiffness springs in high pressure differential constant pressure valves is effectively solved. Secondly, by setting an anti-adsorption protrusion on the end face of the bushing and the spring seat on the valve, the problem of increased probability of adsorption between the valve and the bushing before reaching the working pressure is effectively solved because the valve and the spring seat are designed as an integral structure, which increases the area of ​​the spring seat end face on the valve and the bushing. Third, by setting multiple pressure equalization grooves between the two cavities with a high pressure difference on the valve, the non-axial movement phenomenon caused by the pressure difference force on the valve can be reduced. Fourth, by creating an annular groove in the bushing-type hole area on the inner wall of the housing, an annular cavity is formed between the housing and the bushing that communicates with the upper hole of the bushing, thereby significantly reducing the flow rate of constant pressure oil to the inner wall of the housing and effectively avoiding cavitation caused by high-speed constant pressure oil to the housing. Attached Figure Description

[0015] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0016] Figure 1 This is a schematic diagram of a typical constant pressure valve assembly in the prior art; Figure 2 This is a schematic diagram of a high-pressure differential pressure regulating valve for a hydraulic control system, provided by an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the principle of non-axial movement generated by an existing constant pressure valve under large pressure differential conditions. Figure 4 This is a simulation diagram of a high-pressure differential pressure regulating valve used in a hydraulic control system according to an embodiment of the present invention; Figure 4 Figure a shows the simulation results of oil flow velocity, and Figure b shows the simulation results of oil pressure. Figure 5 This is a schematic diagram showing the position of the flow channel in a high-pressure differential pressure regulating valve for a hydraulic control system, provided in an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0018] As mentioned in the background section, existing constant-pressure valve structures are unsuitable for applications with high pressure differentials and high flow rates, where factors such as increased fuel flow rate, larger spring volume, and non-axial valve movement can negatively impact performance. Specifically, for constant-pressure valves with high pressure differentials and high flow rates, the incoming oil pressure is often high to meet these requirements. This presents new challenges for the design of the constant-pressure valve assembly and its corresponding mounting structure. 1) Due to the high pressure of the constant pressure oil, the spring stiffness increases, and its volume also increases accordingly, which increases the difficulty of designing the constant pressure valve assembly and the corresponding installation structure; 2) Due to the large pressure difference between the incoming oil and the constant pressure oil, the non-axial movement phenomenon of the valve is more serious than that of the low pressure differential constant pressure valve. When the non-axial movement phenomenon is too severe, it will cause the valve to jam, resulting in the downstream control element losing control. 3) Due to the large flow rate, the flow velocity at the constant pressure valve orifice will be high. The high-speed oil will be rapidly ejected from the inside of the valve. If the pressure is lower than the saturated vapor pressure at the shell wall, it will easily cause cavitation and other problems to the aluminum shell. 4) Due to the high stiffness of the spring, it has a weak ability to adapt to disturbances and a large overshoot, which can easily cause pressure fluctuations.

[0019] 5) Since the constant pressure oil outlet also serves as the constant pressure feedback chamber, if pressure fluctuations occur when the constant pressure oil pressure is high, the valve position will also fluctuate. Furthermore, the volume of the feedback chamber is difficult to control, and it is often large, resulting in a slow valve response speed.

[0020] To address the problems existing in existing constant pressure valves, and the design issues of constant pressure valves applied to high pressure differential and high flow conditions, this invention proposes a high pressure differential constant pressure valve and its design method for hydraulic control systems. It is applicable to the design of constant pressure valves with high pressure differential (more than twice the pressure differential of conventional constant pressure valves) and high flow, and belongs to the field of hydraulic control.

[0021] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0022] To address the various problems encountered in the design of constant pressure valves due to increased pressure and flow rate, this invention provides a design method for a high-pressure differential constant pressure valve in a hydraulic control system. Figure 2 This is a schematic diagram of a high-pressure differential pressure regulating valve obtained by using the design method for a high-pressure differential pressure regulating valve in a hydraulic control system provided in an embodiment of the present invention. The design method provided by the present invention includes the following steps and design points: Step 1: Based on the design requirements of the high pressure differential constant pressure valve for the constant pressure valve, determine the stiffness of the spring used in the high pressure differential constant pressure valve, determine the spring diameter based on the spring stiffness, and design the valve and spring seat as an integral structure according to the determined spring diameter. Step 2: Based on the integrated structure of the valve and the spring seat, an anti-adsorption protrusion is provided on the end face of the bushing and the valve where the spring seat abuts against each other, in order to reduce the contact area between the valve and the bushing in the non-working state. Step 3: Based on the characteristic that the high pressure differential constant pressure valve has a large pressure difference at both ends, multiple pressure equalization grooves are opened on the outer wall surface of the valve near the low pressure oil end to reduce the non-axial movement phenomenon formed by the valve under the force of high pressure differential. Step 4: Based on the high flow rate of the oil flowing from the bushing orifice to the inner wall of the housing, an annular groove is opened on the inner wall of the housing in the bushing orifice area to avoid cavitation caused by high-speed constant pressure oil to the housing.

[0023] In one implementation of this invention, step 1 includes: Step 11: The applicable pressure difference of the high pressure differential constant pressure valve is at least twice that of the pressure difference of the conventional constant pressure valve. The spring stiffness of the determined high pressure differential constant pressure valve is at least twice that of the spring stiffness in the conventional constant pressure valve, and the spring diameter is at least twice that of the conventional spring diameter. Step 12: Based on the determined spring diameter, design the valve and spring seat of the high pressure differential pressure regulating valve as an integral structure. The spring seat is located at the low pressure oil end of the valve, and the diameter of the spring seat is larger than the determined spring diameter, so that one end of the spring is mounted against the end face of the spring seat of the integral structure.

[0024] In one implementation of this invention, step 2 is carried out as follows: Based on the integrated structure of the valve and spring seat designed in step 1, the contact area between the end face of the spring seat on the valve and the bushing is increased, which increases the probability of the valve adsorbing with the bushing before reaching the working pressure. By adding an anti-adsorption protrusion to the end face of the bushing and the spring seat on the valve, the contact area between the valve and the bushing in the non-working state is reduced, so as to avoid the valve adsorbing with the bushing before reaching the working pressure.

[0025] In one implementation of this invention, in step 3 above, multiple pressure equalization grooves are opened on the outer wall of the valve between two cavities with a high pressure difference on the valve; and there is a gap between the outer wall of the valve and the bushing at the top of the multiple pressure equalization grooves on the outer wall of the valve; so that when the high pressure differential constant pressure valve is working, the oil flows into the gap and is evenly distributed around the valve, so that the oil pressure is evenly distributed around the valve, thereby reducing the non-axial movement phenomenon formed by the high pressure differential force on the valve.

[0026] In one implementation of this invention, in step 4 above, by creating an annular groove on the housing, an annular cavity is formed between the housing and the bushing that communicates with the upper hole of the bushing. This is equivalent to increasing the flow area of ​​the upper hole of the bushing, thereby significantly reducing the flow rate of the constant pressure oil reaching the inner wall of the housing. This makes the constant pressure oil pressure in the annular cavity uniform, ensuring that the oil in the annular cavity is always higher than the saturated vapor pressure, thereby avoiding cavitation on the aluminum housing.

[0027] Furthermore, based on the above embodiments of the present invention, it also includes: Step 5: Based on the large pressure difference at both ends of the high differential pressure valve and the high stiffness of the spring used, design the pressure chamber volume and feedback nozzle at the valve's constant pressure oil end; design the pressure chamber volume according to the sensitivity requirements of the high differential pressure valve, and design the throttle nozzle according to the stability requirements of the high differential pressure valve under working conditions.

[0028] In one implementation, step 5 above includes: Step 51: A cavity is formed on the constant pressure oil end face of the valve to form a pressure chamber between the valve and the outer bushing and housing, and the volume of the pressure chamber is controlled to be small, for example, less than 1 ml. Step 52: An axial flow groove is formed at a point on the constant pressure oil end face of the valve as a feedback oil nozzle. The flow area of ​​the flow groove is small, for example, less than 1% of the cross-sectional area of ​​the valve 3.

[0029] Based on the design method of the high pressure differential constant pressure valve for hydraulic control system provided in the above embodiments of the present invention, the present invention also provides a high pressure differential constant pressure valve obtained by the above design method, the components of which include: housing 12, valve 3, bushing 4, spring seat 9, spring 10 and end cover 13.

[0030] like Figure 2 and Figure 3 The structure of the high-pressure differential pressure regulating valve shown is designed based on steps 1 to 4 of the design method provided in the above embodiment. In this embodiment, the bushing 4 is sleeved on the valve 3, forming a high-pressure oil flow cavity with the central annular groove of the valve 3. A housing 12 is sleeved on the outside of the bushing 4. The low-pressure oil end of the valve 3 is provided with an integral spring seat 9. The spring 10, which is sleeved on the spring seat 9, is pressed against the other end of the spring 10 by an end cap 13 screwed into the housing 12, and the end cap 13 rests against the end face of the bushing 4. The diameter of the spring 10 is at least twice the diameter of the valve 3, and it is used to provide the spring force to form the high-pressure differential. Figure 2 The diagram also shows the constant pressure valve outlet 7 of the high pressure differential constant pressure valve, the low pressure oil 6, the high pressure oil inlet 8 after the pump, and the gasket 11 located between the spring 10 and the end cover 13.

[0031] In this embodiment of the invention, the bushing 4 is provided with an anti-adsorption protrusion 5 on the side face of the valve 3 near the low-pressure oil end, which is used to reduce the contact area between the valve 3 and the bushing 4 in the non-working state; multiple pressure equalization grooves are opened on the outer wall surface of the valve 3 near the low-pressure oil end, so as to reduce the non-axial movement phenomenon formed by the valve under the action of high pressure difference. In this embodiment of the invention, an annular groove is provided on the inner wall of the housing 12 in the area of ​​the bushing 4-type hole, forming an annular cavity between the housing and the bushing that communicates with the upper hole of the bushing, so as to significantly reduce the flow rate of the constant pressure oil to the inner wall of the housing, and make the constant pressure oil pressure in the annular cavity uniform; and the bushing is also provided with a flow hole for communicating between the annular cavity and the valve constant pressure oil cavity.

[0032] In one implementation of the present invention, based on step 5 of the design method provided in the above embodiment, the valve 3 in this implementation has a concave cavity on the constant pressure oil end face, forming a pressure cavity between the outer bushing 4 and the housing 12. The pressure cavity serves as a constant pressure feedback cavity 1, and the volume of the pressure cavity is relatively small, for example, less than 1 ml. A flow groove 12 is opened along the axial direction at one point on the constant pressure oil end face of the valve 3, serving as a feedback oil nozzle. The flow area of ​​the flow groove 12 is relatively small, for example, the flow area of ​​the flow groove 12 is less than 1% of the cross-sectional area of ​​the valve (3).

[0033] For high-pressure differential, high-flow-rate constant-pressure valves, the incoming oil pressure is often high to meet the requirements of high pressure differential and high flow rate. This makes existing constant-pressure valves unsuitable for applications with high pressure differential and high flow rate, leading to adverse effects such as increased fuel flow rate, larger spring volume, and non-axial movement of the valve. Based on the above problems, this invention provides a high-pressure differential constant-pressure valve for hydraulic control systems and its design method. Specifically, it proposes a structural design scheme to solve the above problems, which has the following beneficial effects: First, by designing the valve and the spring seat for the retaining spring as an integrated structure, the design problem caused by the exponential increase in spring diameter due to the requirement for high stiffness springs in high pressure differential constant pressure valves is effectively solved. Secondly, by setting an anti-adsorption protrusion on the end face of the bushing and the spring seat on the valve, the problem of increased probability of adsorption between the valve and the bushing before reaching the working pressure is effectively solved because the valve and the spring seat are designed as an integral structure, which increases the area of ​​the spring seat end face on the valve and the bushing. Third, by setting multiple pressure equalization grooves between the two cavities with a high pressure difference on the valve, the non-axial movement phenomenon caused by the pressure difference force on the valve can be reduced. Fourth, by creating an annular groove in the bushing-type hole area on the inner wall of the housing, an annular cavity is formed between the housing and the bushing that communicates with the upper hole of the bushing, thereby significantly reducing the flow rate of constant pressure oil to the inner wall of the housing and effectively avoiding cavitation caused by high-speed constant pressure oil to the housing.

[0034] The following is an illustrative example illustrating the design method of the high-pressure differential pressure regulating valve for a hydraulic control system provided in the above embodiments of the present invention.

[0035] (1) Integrated structure design of valve and spring seat When the pressure differential of a constant pressure valve reaches more than twice that of a conventional constant pressure valve, in order to meet the requirements of high pressure differential operation, the constant pressure valve uses a spring with greater stiffness (at least twice the stiffness of a conventional spring), thereby increasing the spring diameter. This spring diameter can be more than twice the diameter of a conventional constant pressure valve spring and larger than the valve diameter. Figure 1In the existing constant pressure valve shown, the spring diameter is similar to the valve diameter, and the large diameter spring poses a challenge to the valve design. Common hydraulic control system constant pressure valves typically have a small bore diameter, while high differential pressure constant pressure valves use springs with a diameter much larger than the valve bore diameter, making the valve and spring seat design difficult. This embodiment proposes designing the spring seat and valve as an integrated structure. The spring seat is located at the low-pressure oil end of the valve, and its diameter is slightly larger than the diameter of the spring used. This allows one end of the spring to abut against the end face of the integrated spring seat, and the spring is pressed in place by an end cap 13 screwed into the housing 12. This effectively solves the design problem caused by the spring diameter being larger than the valve bore diameter, and the integrated structure also reduces the overall weight.

[0036] (2) An anti-adsorption protrusion is added to one end of the bushing. Because the valve and spring seat are designed as a single unit, the contact area between the spring seat end face and the bushing is increased. This makes it prone to adsorption before the valve reaches its working pressure (i.e., the critical state of valve movement), which is detrimental to the stable operation of the high-pressure differential pressure regulating valve. Therefore, an anti-adsorption protrusion is added to the end face of the bushing and the valve where the spring seat abuts. This effectively reduces the contact area between the valve and the bushing in the initial state (i.e., the non-working state), thereby improving the structural stability of the high-pressure differential pressure regulating valve.

[0037] (3) Multiple pressure equalization grooves are designed on the outer wall of the valve to reduce the non-axial movement of the valve. For high-pressure differential valves, the large pressure difference between the constant-pressure oil and low-pressure oil at both ends leads to more severe non-axial movement compared to low-pressure differential constant-pressure valves. This invention proposes adding multiple pressure-equalizing grooves to the outer wall of the valve to reduce non-axial movement. The presence of these grooves ensures even pressure distribution around the valve, suppressing the effect of oil pressure causing the valve to deviate from its axis and preventing jamming. Figure 2 As shown, the number of equalizing grooves depends on the length of the valve structure and is mainly set between two chambers with a high pressure difference, such as between the high-pressure oil chamber and the low-pressure oil chamber.

[0038] like Figure 3 The diagram shown illustrates the principle of non-axial movement generated by an existing constant pressure valve under large pressure differential conditions. Figure 3 As shown, there is a gap between the valve and the bushing. During operation, oil will enter the gap, such as... Figure 3 As shown, without the pressure equalization groove structure of the present invention, the oil in the gap is prone to accumulate on one side of the valve, generating radial force on the valve. The oil in the gap at both ends of the valve will cause the valve to rotate, which will aggravate the non-axial movement phenomenon and eventually cause the valve to jam.

[0039] In this invention, the pressure equalization groove is formed on the outer wall of the valve and surrounds the valve. After the pressure equalization groove is added to the valve surface, the oil entering the gap will flow into the pressure equalization groove and be evenly distributed around the valve. Its oil pressure is also evenly distributed around the valve, so no force will be generated that causes the valve to move non-axially.

[0040] (4) Anti-cavitation design of valve shell In current hydraulic control systems, the oil source for constant pressure valves is often a volumetric pump, resulting in high pressure and a significant pressure difference with the constant pressure oil. Furthermore, due to the small valve orifice and large flow rate, the flow velocity at the constant pressure oil outlet on the bushing (i.e., the orifice on the bushing) is high. Therefore, in the installation structure of high differential pressure constant pressure valves, this invention proposes a special design for the housing located in the orifice region of the bushing. Specifically, an annular groove is created on the inner wall of the housing in the orifice region of the bushing, forming an annular cavity between the housing and the bushing for communication with the orifice on the bushing, effectively increasing the flow area of ​​the orifice on the bushing.

[0041] Simulation results show that in structures without annular grooves on the shell, the highest flow velocity at the upper orifice of the bushing is relatively high. After annular grooves are designed on the shell, the flow velocity of the oil decreases rapidly after reaching the annular cavity through the upper orifice of the bushing, and the flow velocity decreases significantly when it reaches the inner wall of the shell. This makes the constant pressure oil pressure in the annular cavity uniform, and there is no situation where it is lower than the saturated vapor pressure. Therefore, cavitation will not occur on the aluminum shell.

[0042] like Figure 4 The diagram shown is a simulation schematic of a high-pressure differential pressure regulating valve used in a hydraulic control system according to an embodiment of the present invention; the flow field formed by the valve assembly and the housing is extracted for simulation. Figure 4 Figure a shows the simulation results of oil flow velocity. The light blue area is the bushing orifice outlet, where the flow velocity is higher. The dark blue area shows a lower flow velocity, indicating that the flow velocity near the shell wall is only 1 / 8 of the highest flow velocity. Figure b shows the simulation results of oil pressure. The red area represents the cavity formed by the shell and bushing, and the bushing and valve. The red area has higher pressure, representing high-pressure oil from the pump. The blue area represents another cavity formed by the shell and bushing, which contains constant-pressure oil, showing uniform constant-pressure oil pressure.

[0043] (5) Valve adjustment stability setting Because the pressure difference between the constant pressure oil end and the low pressure oil end of the valve is relatively high, and the spring stiffness of the high pressure differential constant pressure valve is relatively large, improper selection of the pressure chamber volume of the constant pressure oil end and the structure and size of the throttle nozzle can lead to poor valve stability, large overshoot, and in severe cases, fluctuations in the constant pressure. Figure 5As shown, on the one hand, this invention cuts a small flow groove along the axial direction at one end of the constant pressure oil face of the valve to serve as a feedback nozzle. Simultaneously, a small constant pressure feedback cavity is formed on the housing. The flow groove replaces the pressure stabilizing nozzle in the existing structure, connecting the constant pressure oil outlet and the constant pressure feedback cavity. This saves structural space for installing the nozzle and effectively reduces valve fluctuation. On the other hand, by controlling the volume of the constant pressure feedback cavity to a small size, this invention ensures timely valve movement and good constant pressure tracking. Theoretical analysis and hydraulic performance simulation show that the natural frequency of the high-pressure differential constant pressure valve structure designed according to this invention can reach over 2000Hz, approximating a first-order inertial element, proving its excellent stability.

[0044] It should be noted that, as Figure 1 The existing constant-pressure valve, as shown, causes changes in the volume of its two cavities (feedback cavity and low-pressure cavity) when it moves. These volume changes require oil to flow in or out. Therefore, the diameter of the nozzles on the oil lines of the feedback cavity and low-pressure cavity determines the valve's moving speed. However, if the nozzles are too large, the valve becomes overly sensitive and prone to fluctuations. Therefore, the existing constant-pressure valve assembly structure requires the installation of pressure-stabilizing nozzles on the oil lines of the feedback cavity or low-pressure cavity to stabilize the pressure and reduce fluctuations during operation. This invention replaces the function of the pressure-stabilizing nozzles in the existing structure by cutting a flow groove at the top of the valve, thus saving space previously used for installing pressure-stabilizing nozzles.

[0045] In addition, because the pressure chamber of the constant pressure oil end is small, less oil is needed to push the valve when it needs to move, which reduces the hydraulic damping effect in the structure. Therefore, when the constant pressure oil pressure is unstable, the valve can move quickly to adjust and ensure the stability of the constant pressure oil pressure.

[0046] Based on theoretical analysis and hydraulic performance simulation, the natural frequency of the high-pressure differential constant-pressure valve structure designed and provided according to this invention can reach over 2000Hz. In the hydraulic system, it can be approximated as a first-order inertial element. Therefore, its overshoot is extremely small, its response is stable, and its output pressure is stable. Apart from the flow channel, no additional stabilization measures are required.

[0047] Using the design method provided in this implementation example, the structure of the high-pressure differential pressure regulating valve is the same as that in the above embodiment of the present invention, such as... Figure 2 and Figure 3As shown; where 1 is a small constant pressure feedback chamber, 2 is a feedback oil nozzle, which is small and can provide better adjustment stability; 3 is a valve, 4 is a bushing, 5 is an anti-adsorption protrusion integrated at the end of the bushing, 9 is a spring seat integrated at the end of the valve, which is used to provide effective support for spring 10, 11 is a gasket, which can adjust the size of the constant pressure difference according to the actual situation; 8 is the high pressure after the pump, that is, the constant pressure oil inlet, 7 is the constant pressure oil outlet of the constant pressure valve, that is, the constant pressure oil after being modulated by the valve, 6 is low pressure oil, which forms the low pressure of the spring chamber, and 12 is the shell, whose annular groove diameter is large, which can effectively eliminate the cavitation effect caused by high pressure and high speed oil.

[0048] This invention proposes a design method for high differential pressure constant pressure valves, which can achieve a high reliability and high stability constant pressure valve structure with small size and light weight. It can be widely applied to various structures in hydraulic control devices that require adjustment of differential pressure oil.

[0049] Currently, the high-pressure differential constant-pressure valve designed using the design method provided by this invention has been applied to fuel control devices of various types of aero-engines and delivered to customers. It has undergone multiple tests and verifications, and its output pressure is stable, its anti-interference ability is strong, and its reliability is high, which can well meet the needs of customers.

[0050] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A design method for a high-pressure differential pressure regulating valve in a hydraulic control system, characterized in that, include: Step 1: Based on the design requirements of the high pressure differential constant pressure valve for the constant pressure valve, determine the stiffness of the spring used in the high pressure differential constant pressure valve, determine the spring diameter based on the spring stiffness, and design the valve and spring seat as an integral structure according to the determined spring diameter. Step 2: Based on the integrated structure of the valve and the spring seat, an anti-adsorption protrusion is provided on the end face of the bushing and the valve where the spring seat abuts against each other, in order to reduce the contact area between the valve and the bushing in the non-working state. Step 3: Based on the characteristic that the high pressure differential constant pressure valve has a large pressure difference at both ends, multiple pressure equalization grooves are opened on the outer wall surface of the valve near the low pressure oil end to reduce the non-axial movement phenomenon formed by the valve under the force of high pressure differential. Step 4: Based on the high flow rate of the oil flowing from the bushing orifice to the inner wall of the housing, an annular groove is opened on the inner wall of the housing in the bushing orifice area to avoid cavitation caused by high-speed constant pressure oil to the housing.

2. The design method for a high-pressure differential pressure regulating valve for a hydraulic control system according to claim 1, characterized in that, Step 1 includes: Step 11: The applicable pressure difference of the high pressure differential constant pressure valve is at least twice that of the pressure difference of the conventional constant pressure valve. The spring stiffness of the determined high pressure differential constant pressure valve is greater than that of the spring stiffness in the conventional constant pressure valve, and the spring diameter is also greater than that of the conventional spring. Step 12: Based on the determined spring diameter, design the valve and spring seat of the high pressure differential pressure regulating valve as an integral structure. The spring seat is located at the low pressure oil end of the valve, and the diameter of the spring seat is larger than the determined spring diameter, so that one end of the spring is mounted against the end face of the spring seat of the integral structure.

3. The design method for a high-pressure differential pressure regulating valve for a hydraulic control system according to claim 2, characterized in that, Step 2 includes: Based on the integrated structure of the valve and spring seat designed in step 1, the contact area between the end face of the spring seat on the valve and the bushing is increased, which increases the probability of the valve adsorbing with the bushing before reaching the working pressure. By adding an anti-adsorption protrusion to the end face of the bushing and the spring seat on the valve, the contact area between the valve and the bushing in the non-working state is reduced, so as to avoid the valve adsorbing with the bushing before reaching the working pressure.

4. The design method for a high-pressure differential pressure regulating valve for a hydraulic control system according to claim 1, characterized in that, In step 3, the multiple pressure equalization grooves opened on the outer wall of the valve are located between the two cavities with a high pressure difference on the valve; and there is a gap between the outer wall of the valve and the bushing at the top of the multiple pressure equalization grooves on the outer wall of the valve; so that when the high pressure differential constant pressure valve is working, the oil flows into the gap and is evenly distributed around the valve, so that the oil pressure is evenly distributed around the valve, thereby reducing the non-axial movement phenomenon caused by the high pressure differential force on the valve.

5. The design method for a high-pressure differential pressure regulating valve for a hydraulic control system according to claim 1, characterized in that, In step 4, by creating an annular groove on the shell, an annular cavity is formed between the shell and the bushing that communicates with the upper hole of the bushing. This is equivalent to increasing the flow area of ​​the upper hole of the bushing, thereby significantly reducing the flow rate of the constant pressure oil to the inner wall of the shell. This makes the constant pressure oil pressure in the annular cavity uniform, ensuring that the oil in the annular cavity is always higher than the saturated vapor pressure, thus avoiding cavitation on the aluminum shell.

6. The design method for a high-pressure differential pressure regulating valve for a hydraulic control system according to any one of claims 1 to 5, characterized in that, Also includes: Step 5: Based on the characteristics of large pressure difference at both ends of the high pressure differential constant pressure valve and the characteristics of high stiffness of the spring used, design the pressure chamber volume and feedback nozzle of the constant pressure oil end of the valve. The pressure chamber volume is designed based on the sensitivity requirements of the high-pressure differential pressure valve, and the throttle nozzle is designed based on the stability requirements of the high-pressure differential pressure valve under working conditions.

7. The design method for a high-pressure differential pressure regulating valve for a hydraulic control system according to claim 6, characterized in that, Step 5 includes: Step 51: A cavity is formed on the constant pressure oil end face of the valve to form a pressure chamber between the valve and the outer bushing and housing, and the volume of the pressure chamber is controlled to be small. Step 52: An axial flow groove is formed at one end face of the constant pressure oil of the valve as a feedback oil nozzle. The flow area of ​​the flow groove is less than 1% of the cross-sectional area of ​​the valve 3.

8. A high-pressure differential pressure regulating valve for a hydraulic control system, characterized in that, The high pressure differential constant pressure valve is designed using the design method for a high pressure differential constant pressure valve for a hydraulic control system as described in any one of claims 1 to 7. The high pressure differential constant pressure valve includes: a housing (12), a valve (3), a bushing (4), a spring seat (9), a spring (10), and an end cap (13). The bushing (4) is fitted onto the valve (3) and forms a high-pressure oil flow cavity with the central annular groove of the valve (3). A housing (12) is fitted onto the outside of the bushing (4). The low-pressure oil end of the valve (3) is provided with an integral spring seat (9). The spring (10) fitted onto the spring seat (9) is pressed against the other end of the spring (10) by an end cap (13) screwed into the housing (12). The end cap (13) rests against the end face of the bushing (4). The diameter of the spring (10) is at least twice the diameter of the valve (3) to provide the spring force to form a high pressure differential. The bushing (4) is provided with an anti-adsorption protrusion (5) on the side face of the valve (3) near the low-pressure oil end, which is used to reduce the contact area between the valve (3) and the bushing (4) in the non-working state; multiple pressure equalization grooves are opened on the outer wall surface of the valve (3) near the low-pressure oil end, so as to reduce the non-axial movement phenomenon formed by the valve under the action of high pressure difference. The inner wall of the housing (12) is provided with an annular groove in the area of ​​the bushing (4) shaped hole, forming an annular cavity between the housing and the bushing that communicates with the shaped hole on the bushing, so as to significantly reduce the flow rate of the constant pressure oil to the inner wall of the housing, making the constant pressure oil pressure in the annular cavity uniform; and the bushing is also provided with a flow hole for communicating between the annular cavity and the valve constant pressure oil cavity.

9. A high-pressure differential pressure regulating valve for a hydraulic control system according to claim 8, characterized in that, The valve (3) has a concave cavity on its constant pressure oil end face, which forms a pressure chamber with the outer bushing (4) and the housing (12), and the volume of the pressure chamber is less than 1 ml; a flow groove (2) is opened along the axial direction on one part of the constant pressure oil end face of the valve (3) as a feedback oil nozzle, and the flow area of ​​the flow groove (2) is less than 1% of the cross-sectional area of ​​the valve (3).

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