Constant flow constant pressure differential combined hydraulic directional control valve

Abstract

The utility model discloses a constant flow constant pressure difference composite hydraulic direction changing valve, including valve core and valve sleeve, three annular grooves are set gradually along the length direction to valve core outer wall surface, its bottom surface all are concave and form long strip gap along valve core length direction, and the long strip gap opening between two adjacent annular grooves is staggered and set gradually to opposite direction, oil return, work oil port, high pressure oil inlet, work oil port and oil return are set gradually on the valve sleeve, and the long strip gap of the same direction of the both sides of the middle annular groove is located on the same straight line, so that valve core rotation P port optional with A port or B port intercommunication, the valve core still is set to move along the valve sleeve straight line to make work oil port A port or B port and corresponding long strip gap partial or all intercommunication. The utility model discloses through the valve core rotating speed and axial position adjustment, can adjust the flow, can adjust the pressure difference again, realizes the flow and pressure double parameter control, reduces the comprehensive energy consumption.

Description

Technical Field

[0001] This utility model relates to hydrogen energy equipment, particularly in the field of hydrogen pressurization technology. More specifically, this utility model relates to a constant flow and constant pressure differential composite hydraulic directional valve. Background Technology

[0002] Hydrogen refueling stations require hydrogen compressors to operate at high purity, with large displacement and frequent start-stop cycles. Liquid-driven diaphragm hydrogen compressors are among the equipment capable of meeting all these requirements. The high-speed rotary reversing valve is the core control valve of the liquid-driven diaphragm hydrogen compressor, and it is the key component for matching the output flow of the hydraulic system with the required flow of the oil-side diaphragm head of the compressor.

[0003] Existing hydraulic diaphragm hydrogen compressors use reversing valves that adjust the compressor flow rate by changing the valve's rotation speed. The flow area depends entirely on the rotation angle of the multi-way valve core and can only regulate flow rate, not simultaneously adjust the pressure difference across the multi-way valve. In other words, it can only rotate, not slide precisely and controllably. While it provides good flow control, it lacks pressure control. This not only hinders the improvement of compressor operating efficiency but also prevents precise flow control, thus compromising the reliability of compressor operation. Utility Model Content

[0004] One objective of this invention is to provide a constant flow and constant pressure differential composite hydraulic directional valve, which enables the valve's flow rate and pressure differential to be dynamically adjusted according to the needs of the controlled object. On the one hand, this avoids unnecessary energy loss caused by overflow, and on the other hand, it avoids the displacement and speed of the controlled object failing to meet the usage requirements due to insufficient flow supply.

[0005] To solve the above-mentioned technical problems, this utility model provides a constant flow and constant pressure differential composite hydraulic directional valve, including a valve core and a valve sleeve arranged coaxially. The valve core is sealed inside the valve sleeve and driven to rotate by a driving mechanism. Three concave annular grooves are sequentially arranged along the length of the outer wall of the valve core. The bottom surface of each groove is concave along the length of the valve core to form a long strip-shaped notch penetrating the outer wall of the valve core. Multiple long strip-shaped notches between adjacent annular grooves are evenly spaced along the circumference of the valve core, and their openings are staggered in opposite directions. The valve sleeve is sequentially provided with... The valve core has five openings, which are respectively connected to a one-sided annular groove, a one-sided elongated notch, a middle annular groove, another elongated notch, and another annular groove. The elongated notches on both sides of the middle annular groove are aligned in the same direction and are on the same straight line, so that when the valve core rotates, the P port can selectively connect with the A port or the B port. The valve core is also configured to move synchronously along the valve sleeve so that the working oil port A port or the B port can partially or completely connect with the corresponding elongated notch.

[0006] Preferably, the high-pressure oil inlet P port is connected to an oil pump to continuously supply high-pressure oil into the central annular groove, the working oil inlets A and B ports are respectively connected to the two ends of the actuator, and the two return oil inlets T ports are both connected to the oil tank.

[0007] Preferably, the central annular groove is located in the middle of the valve core, and the two annular grooves are symmetrically arranged on both sides of the central annular groove and on both sides of the valve core.

[0008] Preferably, a control chamber is provided on one side of the valve core end, and a control spring is provided on the other side. The control chamber is connected to the high-pressure oil inlet P through a connecting pipe via a connecting port on the valve sleeve. A pressure reducing valve is provided on the connecting pipe, and the valve core is driven to move linearly by controlling the amount of oil in the control chamber.

[0009] Preferably, one side of the valve core is rotatably connected by a connecting block, and a control chamber is formed between the connecting block, the end face of the valve core, and the inner wall of the valve sleeve, and the end of the valve core is linearly slidably connected to the connecting block.

[0010] Preferably, the other side of the valve core is rotatably connected via a connector, the connector is rotatably connected to the valve sleeve and driven by a drive mechanism to rotate the valve core, the control spring is sleeved on the connector and tightly abuts against the end face of the valve core, and the end of the valve core is linearly slidably connected to the connector.

[0011] This utility model has at least the following beneficial effects: (1) This utility model can adjust both the flow rate and the pressure difference by adjusting the valve core speed and axial position, thereby achieving dual parameter control of flow rate and pressure and reducing overall energy consumption.

[0012] (2) This utility model uses dual variable control, which allows the valve core to rotate and slide simultaneously, improving the flow and differential pressure output accuracy of the reversing valve, thereby improving control accuracy and thus enhancing response accuracy.

[0013] (3) The constant flow horizontal pressure difference composite hydraulic reversing valve proposed in this utility model can realize the dynamic matching between the output flow of the hydraulic system and the oil side diaphragm head demand flow of the liquid-driven diaphragm hydrogen compressor, providing support for the reliable and efficient operation of the liquid-driven diaphragm hydrogen compressor.

[0014] (4) This utility model is applicable to hydraulic or pneumatic systems that require high-speed and high-precision reversing, and has broad application prospects.

[0015] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a schematic diagram of the overall structure and appearance of this utility model; Figure 4 This is a schematic diagram of the valve core structure of this utility model; Figure 5 This is a schematic diagram showing the overall structure of this utility model connected to the external structure; Figure 6 This is a schematic diagram illustrating the overall structural parameters of this utility model; Figure 7 This is a schematic diagram showing the cross-sectional parameters of the valve core of this utility model.

[0017] Explanation of reference numerals in the attached figures: 1. Valve sleeve, 2. Valve core, 3. Annular groove, 4. Long strip notch, 5. T port, 6. A port, 7. P port, 8. B port, 9. Control chamber, 10. Control spring, 11. Pressure reducing valve, 12. Connecting block, 13. Connecting piece, 14. Connecting port, 15. Oil cylinder. Detailed Implementation

[0018] To better understand the purpose, structure, and function of this utility model, the following detailed description is provided in conjunction with the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0019] It should be noted that in the description of this utility model, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] like Figures 1 to 5As shown, this utility model provides a constant flow and constant pressure differential composite hydraulic directional valve, including a valve core 2 and a valve sleeve 1 coaxially arranged. The valve core is sealed inside the valve sleeve and driven to rotate by a drive mechanism. The outer wall of the valve core has three concave annular grooves 3 arranged sequentially along its length. The bottom surface of each groove is concave along the length of the valve core to form a long strip-shaped notch 4 that penetrates the outer wall of the valve core. Multiple long strip-shaped notches between two adjacent annular grooves are evenly spaced along the circumference of the valve core, and their openings are staggered in opposite directions. The valve sleeve has five openings arranged sequentially along its length, which are respectively connected to one annular groove, one long strip-shaped notch, the middle annular groove, and... The valve core has a long, narrow notch on one side, an annular groove on the other side, and a return port T5 (oil can only enter, not flow out), a working port A6, a high-pressure oil inlet P7 (oil can only enter, not flow out), a working port B8, and a return port T8. A and B are two working ports, allowing oil to both enter and exit, with the specific flow direction depending on the valve's position. The long, narrow notches on both sides of the central annular groove, facing the same direction, are aligned on a straight line, allowing port P to selectively connect with either port A or port B when the valve core rotates. The valve core is also configured to move synchronously along the valve sleeve, allowing working ports A or B to partially or completely connect with the corresponding long, narrow notches. The high-pressure oil inlet P is connected to an oil pump for continuously supplying high-pressure oil into the central annular groove. Working ports A and B are connected to both ends of the actuator, and both return ports T are connected to the oil tank. The central annular groove is located in the middle of the valve core, and the two annular grooves on either side are symmetrically arranged on either side of the central annular groove and on both sides of the valve core.

[0021] The drive mechanism can be a servo motor, which drives the valve core to rotate. Simultaneously, the valve core can also slide linearly, providing dual control capabilities for pressure and flow in the fluid control system, enabling simultaneous control of both. In practical applications, some products require a constant pressure when a flow rate is given; in existing products, the pressure inevitably changes after a flow rate is given. This application achieves constant pressure at a given flow rate through synchronous linear movement. The core principle is that this application changes the connection area between working ports A and B through linear movement, thereby coordinating the relationship between flow rate and pressure. The cylinder movement requires both a certain force to drive its load and a certain flow rate to propel the load at a certain speed. This application controls the flow direction and flow rate through rotation, and simultaneously controls the pressure while maintaining consistent flow at the control valve ports through translation, thus minimizing losses.

[0022] The valve core is driven to rotate, and the high-pressure oil inlet P port is always connected to high-pressure oil. The working oil ports A and B are connected to the actuator, such as the two sides of the hydraulic cylinder 15. By rotating the valve core, the high-pressure oil inlet P port is selectively connected to port A or port B, changing the flow direction of the high-pressure oil and realizing the reversal of the hydraulic cylinder, so that the hydraulic cylinder can move in different directions.

[0023] This application incorporates both linear movement and rotary rotation for regulating pressure and flow. A rotary motor drives the directional valve to switch oil circuits, similar to the working principle of a conventional rotary directional valve. Linear movement changes the flow area of ​​valve ports A and B. According to the valve flow formula, for the same flow rate, a larger valve port area results in a smaller pressure difference across the port, leading to less energy loss and achieving energy saving. Furthermore, when the hydraulic oil demanded by the actuator decreases, the opening of valve port A or B can be adjusted via linear movement to control the amount of hydraulic oil entering the actuator and change its speed.

[0024] In another specific embodiment, a control chamber 9 is provided on one side of the valve core end, and a control spring 10 is provided on the other side. The control chamber is connected to the high-pressure oil inlet P through a connecting pipe via a connecting port 14 on the valve sleeve. A pressure reducing valve 11 is provided on the connecting pipe, and the valve core is driven to move linearly by controlling the oil volume in the control chamber. One side of the valve core is rotatably connected by a connecting block 12, and a control chamber is formed between the connecting block, the valve core end face, and the inner wall of the valve sleeve. The valve core end is linearly slidably connected to the connecting block. The other side of the valve core is fixedly connected by a connecting member 13, which is rotatably connected to the valve sleeve and drives the valve core to rotate through a driving mechanism. The control spring is sleeved on the connecting member and tightly abuts against the valve core end face. The valve core end is linearly slidably connected to the connecting member.

[0025] Initially, the valve is controlled to its initial position by a spring. High-pressure oil is introduced into the other control chamber, driving the valve core to move. Different oil pressures result in different moving distances and speeds, and thus different connection areas at ports A and B. High-pressure oil is introduced into the left control chamber through port P. A pressure-reducing valve on the connecting pipeline ensures a constant pressure for the introduced high-pressure oil, and the spring compression is also determined. This regulates both the valve flow rate and the valve port flow area.

[0026] One side of the connector is connected to the valve core, and the other side is connected to a servo motor. The middle of the connector is rotatably connected via a bearing, and a control spring is sleeved on the connector and pressed against the bearing seat. Both the connector and the connecting block have recessed openings at their ends, with multiple recessed channels within these openings. The valve core has multiple protrusions at its end that precisely engage with these recessed channels, allowing the valve core end to engage with the end of the connector or connecting block and enabling only linear sliding. The distance between the bottom surfaces of the openings at the ends of the connector or connecting block is greater than the length of the valve core. During rotation, the valve core and the connector rotate together; during movement, the valve core moves linearly between the connector and the connecting block.

[0027] like Figure 6 and Figure 7 As shown, the rotation of the directional valve causes a change in the flow area of ​​the valve core, thus causing a change in the differential pressure. Simultaneously, during axial linear movement, the axial opening of the valve core changes, altering the flow area and also causing a change in differential pressure. This application, through structural design and corresponding control methods, achieves a situation where the flow rate and differential pressure output from the valve port remain unchanged during valve movement. This ensures stable equipment operation while reducing operating noise and energy consumption. The flow calculation formula is shown below: ; in, q - flow rate, A - valve core flow area, L - valve core circumferential opening, z - valve core axial opening, R - valve core radius, k - control spring stiffness, Ar - valve core control chamber area, t - time, Ps - oil pump outlet pressure, i.e., pressure at port P. - Valve core rotation angle (initial angle is) Figure 5 middle (Position 0), ω - valve core rotational angular velocity, P L - Cylinder load / working pressure, z0 - Control spring compression corresponding to the initial position of the valve core (the valve port is fully open when the spring is completely uncompressed and free), p - Pressure in the control chamber, Δp - Pressure difference, Cd - Flow coefficient. -Initial valve position angle, the angle corresponds to... Figure 5 middle The position where 0 is.

[0028] The directional valve of this application can simultaneously rotate and move axially. The circumferential opening of the valve core is adjusted by regulating the rotational speed of the rotary valve via a servo motor, and the axial opening is adjusted by regulating the pressure in the control chamber via an electromagnetic pressure reducing valve. Ultimately, the flow area of ​​the valve is controllable during the rotary valve's rotational movement. When the pump flow rate remains constant, the pressure difference of the composite hydraulic directional valve can remain constant, i.e., the following product remains unchanged.

[0029] Further transformed into: .

[0030] Therefore, during the rotation of the composite hydraulic directional valve, by simply adjusting the pressure φ in the control chamber according to the above formula, the flow rate and pressure differential output from the valve port remain unchanged during valve movement. This ensures stable equipment operation while reducing operating noise and energy consumption.

[0031] This utility model relates to a dual control method for a constant flow and constant pressure differential composite hydraulic directional valve, comprising the following steps: Step 1: Determine the desired rotary valve flow rate. and the corresponding pressure difference ; Step 2: Based on the physical relationship between flow rate, pressure difference, and flow area, establish the relationship between pressure difference and rotation angle (corresponding to the circumferential opening of the valve port) and Z-axis axial displacement (corresponding to the axial opening of the valve port) at a specified flow rate. ; Step 3: Assume the initial valve opening in the Z-axis direction is at the middle position. The desired flow rate through the rotary valve According to the rotary valve angle corresponding to equation (2) ; Step 4: Monitor the pressure difference between the inlet and outlet of the rotary valve using sensors to determine if it is within acceptable limits. If not equal to By adjusting the output pressure of the pressure reducing valve, the pressure of the hydraulic oil entering the control chamber changes, thereby pushing the rotary valve core to move axially along the Z-axis, causing the axial opening to... Become This causes the rotary valve's output flow rate to... and the pressure difference between the two ends All reached the preset values; Step 5: During the rotation of the rotary valve, the axial movement of the valve core follows the circumferential rotation of the valve core according to formula (2), thereby achieving the purpose of constant flow and constant pressure difference output.

[0032] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model, and other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and examples shown and described herein.

Claims

1. A constant flow rate and constant pressure differential composite hydraulic directional valve, characterized in that, The valve includes a valve core and a valve sleeve arranged coaxially. The valve core is sealed inside the valve sleeve and driven to rotate by a drive mechanism. The outer wall of the valve core has three concave annular grooves arranged sequentially along its length. The bottom surface of each groove is concave along the length of the valve core to form a long strip-shaped notch that penetrates the outer wall of the valve core. Multiple long strip-shaped notches between two adjacent annular grooves are evenly spaced along the circumference of the valve core, and their openings are staggered in opposite directions. The valve sleeve has five openings arranged sequentially along its length. These openings are, in order, a return oil port T, a working oil port A, a high-pressure oil inlet P, a working oil port B, and a return oil port T, which are respectively connected to one annular groove, one long strip-shaped notch, a middle annular groove, another long strip-shaped notch, and another annular groove. The long strip-shaped notches on both sides of the middle annular groove, facing the same direction, are located on the same straight line, so that when the valve core rotates, port P selectively connects to port A or port B. The valve core is also configured to move synchronously along the valve sleeve so that port A or port B partially or completely connects to the corresponding long strip-shaped notch.

2. The constant flow rate and constant pressure differential composite hydraulic directional valve as described in claim 1, characterized in that, The high-pressure oil inlet P port is connected to an oil pump to continuously supply high-pressure oil into the central annular groove. The working oil ports A and B are connected to the two ends of the actuator, respectively, and the two return oil ports T ports are both connected to the oil tank.

3. The constant flow and constant pressure differential composite hydraulic directional valve as described in claim 1, characterized in that, The central annular groove is located in the middle of the valve core, and the two annular grooves on both sides are symmetrically arranged on both sides of the central annular groove and located on both sides of the valve core.

4. The constant flow rate and constant pressure differential composite hydraulic directional valve as described in claim 1, characterized in that, A control chamber is provided on one side of the valve core end, and a control spring is provided on the other side. The control chamber is connected to the high-pressure oil inlet P through a connecting pipe on the valve sleeve. A pressure reducing valve is provided on the connecting pipe. The valve core is driven to move linearly by controlling the amount of oil in the control chamber.

5. The constant flow rate and constant pressure differential composite hydraulic directional valve as described in claim 4, characterized in that, One side of the valve core is rotatably connected by a connecting block, and a control chamber is formed between the connecting block, the end face of the valve core, and the inner wall of the valve sleeve. The end of the valve core is linearly slidably connected to the connecting block.

6. The constant flow rate and constant pressure differential composite hydraulic directional valve as described in claim 4, characterized in that, The other side of the valve core is rotatably connected by a connector. The connector is rotatably connected to the valve sleeve and driven by a drive mechanism to rotate the valve core. The control spring is sleeved on the connector and tightly abuts against the end face of the valve core. The end of the valve core is linearly slidably connected to the connector.

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