A pilot high flow balancing valve with overcompensation adjustment function

Abstract

The present invention discloses a pilot-operated, high-flow balancing valve with an overcompensation adjustment function. The valve comprises a main valve body, a pilot valve body, and a control end cap, arranged axially from front to back, along with a main valve core, a pilot valve core, and a control piston coaxially arranged within an internal cavity. A throttle valve assembly is inserted into the main valve body, communicating with the feedback chamber between the main valve core and the pilot valve core, and with the transition chamber between the pilot valve core and the pilot valve body. The present invention integrates the throttle valve function into the main valve body, controlling the overcompensation characteristics of the entire valve by adjusting the flow area of ​​the throttle valve assembly. This effectively controls the lowering speed under overload, maintains the original dynamic characteristics, and ensures system safety while maintaining a large adjustment range.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic control, and in particular to a pilot large-flow balancing valve with an overcompensation adjustment function. Background Art

[0002] Balancing valves are widely used in hydraulic systems with overload conditions, and they play a role in regulating the speed of lowering the overload, providing back pressure, and maintaining the load.

[0003] For example, truck cranes can experience overload during lifting, telescoping, and luffing operations. Luffing, in particular, involves load variations with the luffing angle, placing high demands on the controllability of the counterbalance valve. The control characteristics of traditional counterbalance valves are highly susceptible to load fluctuations, leading to jitter or stalling when the load suddenly increases, compromising the safety of the entire machine. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention proposes a pilot high-flow balancing valve with an over-compensation adjustment function.

[0005] The specific technical solutions are as follows:

[0006] A pilot high-flow balancing valve with an over-compensation adjustment function comprises a main valve body, a pilot valve body, and a control end cover, which are arranged in sequence axially from front to back, and the three constitute a main valve body; the main valve body and the pilot valve body are both provided with axial cavities and are interconnected; the main valve sleeve is arranged in the cavity in the main valve body; annular grooves are provided on the inner walls corresponding to the middle of the main valve body and the main valve sleeve, forming a load chamber between the main valve body and the main valve sleeve; a load port B is provided on the main valve body to connect the outside with the load chamber; a plurality of radial through holes are provided in the middle of the main valve sleeve to connect the load chamber with the internal cavity of the main valve sleeve; the front end of the pilot valve sleeve is arranged in the cavity in the main valve body and is coaxially and tightly attached to the main valve sleeve, and the rear end is arranged in the front part of the cavity in the pilot valve body;

[0007] The main valve core is coaxially slidably arranged in the cavity inside the main valve sleeve, and the pilot valve core is coaxially slidably arranged in the cavity inside the pilot valve sleeve; the main valve core and the pilot valve core are coaxially arranged in opposite directions, and the large diameter end of the main valve core is opposite to the large diameter end of the pilot valve core, and a feedback cavity is formed among the main valve core, the pilot valve core, the main valve sleeve and the pilot valve sleeve. A throttling groove is provided on the main valve core to connect the load cavity with the feedback cavity; one end of the feedback spring is against the large diameter end of the main valve core, and the other end is against the large diameter end of the pilot valve core; between the small diameter end of the main valve core and the main valve body The cavity is the back pressure cavity, and the main valve body is provided with an oil port A to connect the outside with the back pressure cavity; in the initial state of the balancing valve, the main valve core is located at the front end of the axial limit and forms a conical surface seal with the main valve sleeve, and the pilot valve core is located at the rear end of the axial limit and forms a conical surface seal with the pilot valve sleeve; the cavity between the small diameter end of the pilot valve core and the inside of the pilot valve sleeve forms a transition cavity; the throttle valve assembly is installed on the main valve body, and a channel is provided inside the main valve body to connect the cavity inside the throttle valve assembly with the feedback cavity and the transition cavity respectively;

[0008] A back pressure feedback chamber is formed between the rear end of the pilot valve sleeve and the pilot valve body; a channel is provided in the pilot valve sleeve and the main valve body so that the load port B is connected to the feedback chamber in the initial state of the balancing valve, that is, when the pilot valve port is closed; when the pilot valve port is opened, the load port B is not connected to the feedback chamber, and the back pressure feedback chamber is connected to the transition chamber; a channel is provided inside the valve body to connect the back pressure feedback chamber with the back pressure chamber, and a damper is arranged in the channel; the control piston is coaxially arranged at the rear part of the cavity in the pilot valve body, and under the action of the pilot control spring, the control piston The disk of the plug is in contact with the control end cover and a pilot control chamber is left between the two; the small-diameter end of the pilot valve core passes through the pilot valve sleeve and is installed against the shaft of the control piston; the cavity between the control piston and the pilot valve body is the oil drain chamber, and the pilot valve body is provided with an oil port L to connect the outside with the oil drain chamber; the control end cover is provided with an X port to connect the outside with the pilot control chamber, and the pilot control chamber and the oil drain chamber are connected through a channel provided in the control piston, and dampers are arranged in the channel between the X port and the pilot control chamber and in the channel between the pilot control chamber and the oil drain chamber.

[0009] Furthermore, a first annular groove is formed on the outer periphery of the pilot valve sleeve, and symmetrically distributed radial through holes are formed on the first annular groove to communicate with the feedback chamber; a throttle valve mounting hole is formed on the outer wall of the main valve body, and a first radial hole is formed on the inner wall of the main valve body at a position corresponding to the first annular groove to communicate with the throttle valve mounting hole;

[0010] A throttle valve assembly is installed in the throttle valve mounting hole, and the assembly includes: a throttle valve sleeve, a throttle end cover, and a throttle valve core; a thread is provided on the inner circumference of the throttle valve mounting hole, and a thread matching the thread is provided on the outer circumference of the throttle valve sleeve, which is screwed into the throttle valve mounting hole, and the throttle valve sleeve and the main valve body are sealed; the throttle end cover is coaxially installed in a through hole coaxially opened inside the throttle valve sleeve, and the throttle end cover and the throttle valve sleeve are sealed; there is a cavity between the throttle valve sleeve and the throttle end cover, and a through hole is provided on the side wall of the throttle valve sleeve corresponding to the cavity as a throttle valve port, which is connected to the transition cavity through the axial internal channel opened by the main valve body and the pilot valve body, and the second radial hole opened on the rear side of the pilot valve sleeve; the throttle valve core is installed in the through hole coaxially opened inside the throttle end cover, and the throttle valve core and the throttle end cover are sealed; a through hole is provided at the bottom of the throttle valve sleeve to communicate with the first radial hole.

[0011] Furthermore, the main valve core comprises, from front to back, a coaxial damping tail structure, a tapered section, and a cylindrical section. The connection between the cylindrical section and the tapered section and the main valve sleeve forms the main valve port of the pilot large-flow balancing valve. In the initial state of the balancing valve, the main valve core is located at the front end of the axial limit, and a conical surface seal is formed between the connection between the cylindrical section and the tapered section and the main valve sleeve. The main valve port is closed, and the back pressure chamber and the load chamber are not connected. When the main valve core moves backward, the main valve port is opened, and the back pressure chamber and the load chamber are connected.

[0012] The throttling groove is symmetrically arranged at the tail end of the outer circumference of the cylindrical section of the main valve core. The throttling groove includes a U-shaped groove and a feedback throttling groove arranged in sequence from front to back and connected to each other, and the depth and width of the feedback throttling groove are both smaller than the U-shaped groove. The throttling groove is used to connect the load chamber and the feedback chamber, and the end surface where the throttling groove is connected to the feedback chamber forms a feedback valve port.

[0013] Furthermore, a first stepped through hole is axially provided inside the pilot valve body, and the first stepped through hole comprises, from front to back, a first cylindrical hole, a second cylindrical hole, a third cylindrical hole, and a fourth cylindrical hole;

[0014] The rear end of the pilot valve sleeve is installed in the first cylindrical hole. The first cylindrical hole is used to limit the pilot valve sleeve axially and radially. The inner diameter of the first cylindrical hole is the same as the outer diameter of the pilot valve sleeve, and the pilot valve sleeve and the first cylindrical hole are sealed by an O-ring.

[0015] The inner diameter of the second cylindrical hole is adapted to the outer diameter of the small diameter end of the pilot valve core extending out of the outside of the pilot valve sleeve; an annular partition is coaxially fixedly connected to the position connected to the second cylindrical through hole in the third cylindrical hole, and a through hole adapted to the outer diameter of the shaft of the control piston is opened on the annular partition; the shaft of the control piston and the small diameter end of the pilot valve core are coaxially mounted opposite each other in the through hole inside the annular partition, and a gap is left between the shaft of the control piston and the small diameter end of the pilot valve core in the initial state of the balancing valve; the pilot control spring is installed between the disk of the control piston and the annular partition, one end of which rests against the front end of the third cylindrical hole, and the other end rests against the control piston; and the inner diameter of the third cylindrical hole is adapted to the outer diameter of the pilot control spring; the inner diameter of the fourth cylindrical hole is adapted to the outer diameter of the disk of the control piston.

[0016] Furthermore, O-rings are used to seal the main valve body and the pilot valve body, the main valve sleeve and the main valve body, the pilot valve sleeve and the main valve body, the pilot valve sleeve and the pilot valve body, and the main valve sleeve and the pilot valve sleeve.

[0017] Furthermore, a channel is opened in the pilot valve sleeve and the main valve body so that when the pilot valve port is closed, the load port B is connected with the feedback chamber. Specifically, an annular groove is opened on the outer wall of the middle part of the pilot valve sleeve as a quick-closing chamber, and symmetrically distributed radial through holes are opened along the annular groove to connect the quick-closing chamber with the internal cavity of the pilot valve body. A channel is opened inside the main valve body to connect the quick-closing chamber with the load port B; and in the initial state of the balancing valve, the quick-closing chamber is connected with the feedback chamber. When the pilot valve port is opened, the channel between the quick-closing chamber and the feedback chamber is covered, and the quick-closing chamber and the feedback chamber are not connected.

[0018] Furthermore, the damper arranged in the back pressure feedback chamber and the back pressure chamber connecting channel, the damper arranged in the channel between the X port and the pilot control chamber, and the damper arranged in the channel between the pilot control chamber and the oil drain chamber are all sleeve structures with a small through hole opened on the axis, and are installed in each channel by threaded rotation.

[0019] Furthermore, a back pressure feedback chamber is formed between the rear end of the pilot valve sleeve and the pilot valve body. Specifically, a cylindrical hole is radially opened inside the pilot valve body along the contact surface of the pilot valve body and the pilot valve sleeve perpendicular to the axis, so that a cavity is formed between the pilot valve body and the pilot valve sleeve, which is recorded as the back pressure feedback chamber.

[0020] The beneficial effects of the present invention are:

[0021] (1) Under the condition of overload, the present invention controls the overcompensation characteristics of the entire valve by adjusting the flow area of ​​the valve core, and adjusts the inflection point of the overcompensation characteristics within a certain range, which can effectively prevent the stall and decline phenomenon caused by the increase of system load pressure, improve the impact and vibration resistance to a certain extent, and maintain the original dynamic characteristics and adjustment range.

[0022] (2) The present invention integrates the regulating function into the main valve body, so that the pilot large flow balancing valve has fewer parts, a simple and compact structure, and higher reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a front view of a pilot large flow balancing valve with an overcompensation adjustment function in an embodiment of the present invention.

[0024] Figure 2 It is an AA cross-sectional view of a pilot large flow balancing valve with an overcompensation adjustment function in an embodiment of the present invention.

[0025] Figure 3 It is a top view of a pilot large flow balancing valve with an overcompensation adjustment function in an embodiment of the present invention.

[0026] Figure 4 It is a BB cross-sectional view of a pilot large flow balancing valve with an overcompensation adjustment function in an embodiment of the present invention.

[0027] Figure 5 Schematic diagram of the structure of the main valve core in an embodiment of the present invention.

[0028] Figure 6 This is a schematic diagram of the working state and oil flow direction of the pilot large-flow balancing valve with overcompensation adjustment function when the load is lowered, from the AA cross-sectional perspective in an embodiment of the present invention.

[0029] Figure 7 It is a schematic diagram of the working state and oil flow direction of the pilot large flow balancing valve with overcompensation adjustment function when the load is lowered from the BB cross-sectional perspective in an embodiment of the present invention.

[0030] Figure 8 3 is a comparative curve diagram of the over-compensation characteristics of the throttle valve core under different displacements and load pressures in the embodiment of the present invention.

[0031] In the figure, main valve body 1, main valve core 2, main valve sleeve 3, feedback spring 4, throttle valve sleeve 5, throttle end cover 6, throttle valve core 7, pilot valve sleeve 8, pilot valve core 9, pilot valve body 10, pilot control spring 11, control piston 12, control end cover 13, pilot inlet damping 14, pilot control chamber 15, outlet damping 16, oil drain chamber 17, transition chamber 18, quick closing chamber 19, overcompensation damping 20, feedback chamber 21, load chamber 22, back pressure chamber 23, back pressure feedback chamber 24, back pressure feedback damping 25, back pressure feedback channel 26, and annular partition 27. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become more apparent. The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0033] like Figures 1-4 As shown, a pilot high-flow balancing valve with overcompensation adjustment function includes, arranged from left to right, a main valve body 1, a pilot valve body 10, and a control end cover 13. The main valve body 1 and the pilot valve body 10 are coaxially fixed together by bolts to form the main valve body. The internal cavity of the main valve body 1 communicates with the internal cavity of the pilot valve body 10, forming the main valve cavity. A sealing ring is installed between the internal cavity and the pilot valve body 10 to prevent leakage. The control end cover 13 is bolted to the right end of the pilot valve body 10. A central hole is defined in the end surface of the control end cover 13 as the control port X of the pilot high-flow balancing valve. A sealing ring is installed at the connection between the control end cover 13 and the pilot valve body 10 to prevent leakage. The balancing valve also includes a main valve core assembly disposed within the internal cavity of the main valve body 1, a pilot valve core assembly disposed within the internal cavity of the pilot valve body 10, and a control piston 12, all connected via springs or through-holes. It also includes a feedback spring 4, a pilot control spring 11, a throttle valve sleeve 5, a throttle valve core 7, and an overcompensation damper 20. Multiple cavities exist within the main valve body, including a backpressure chamber 23, a load chamber 22, a feedback chamber 21, a fast-closing chamber 19, a transition chamber 21, a backpressure feedback chamber 23, an oil drain chamber 17, and a pilot control chamber 15, which collectively control the flow and pressure of the valve body.

[0034] Specifically, the main valve core assembly includes: a main valve core 2 and a main valve sleeve 3. The pilot valve core assembly includes: a pilot valve core 9 and a pilot valve sleeve 8. A first stepped blind hole is provided at the right end of the main valve body 1, and a first stepped through hole is axially provided inside the pilot valve body 10. The first stepped blind hole and the first stepped through hole are coaxial. The first stepped through hole includes, from left to right, a first cylindrical hole, a second cylindrical hole, a third cylindrical hole, and a fourth cylindrical hole. The inner diameter of the first cylindrical hole is the same as the outer diameter of the pilot valve sleeve 8, and the inner diameter of the second cylindrical hole matches the outer diameter of the small-diameter end of the pilot valve core 9. The main valve sleeve 3 is installed in the first stepped blind hole. The design of the first stepped blind hole achieves axial and radial limitation of the main valve sleeve 3. The main valve sleeve 3 and the main valve body 1 are sealed by an O-ring. An annular groove is provided on the inner wall corresponding to the middle position of the main valve body 1 and the main valve sleeve 3. The pilot valve sleeve 8 is coaxially arranged with the main valve sleeve 3. The left end of the pilot valve sleeve 8 is installed in the first stepped blind hole and is tightly attached to the right end of the main valve sleeve 3. The right end of the pilot valve sleeve 8 is installed in the first cylindrical hole on the left end of the pilot valve body 10, thus limiting the axial and radial position of the pilot valve sleeve 8. The pilot valve sleeve 8 and the pilot valve body 10 are sealed by an O-ring, and the main valve sleeve 3 and the pilot valve sleeve 8 are also sealed by an O-ring.

[0035] A central through-hole is coaxially defined within the main valve sleeve 3. The main valve core 2 is coaxially mounted within the sleeve 3, with its smaller-diameter end forming the left end and its larger-diameter end forming the right end. A sliding fit forms between the main valve core 2 and the sleeve 3, allowing the main valve core 2 to move axially freely within the through-hole of the sleeve 3 without binding. A back-pressure chamber 23 is formed in the cavity between the smaller-diameter end (i.e., the left end) of the main valve core 2 and the main valve body 1. Radially defined oil ports are provided on the sidewall of the main valve body 1 surrounding the back-pressure chamber 23 and communicate with the back-pressure chamber 23. These ports serve as port A of the pilot high-flow balancing valve and are subsequently used for communication with the outside world. Several radial holes are defined in the middle of the main valve sleeve 3 and communicate with the cavity within it. The cavity between the middle of the main valve core 2, the main valve sleeve 3, and the sidewall of the main valve body 1 forms a load chamber 22. A radially defined oil port is provided on the sidewall of the main valve body 1 corresponding to the load chamber 22 and communicates with the load chamber 22. These ports serve as port B of the high-flow balancing valve and are subsequently used for communication with the outside world. A feedback chamber 21 is formed among the large-diameter end of the main valve core 2 , the main valve sleeve 3 , the pilot valve sleeve 8 , and the large-diameter end of the pilot valve core 9 .

[0036] The main valve core 2 has a second-step blind hole centered on the valve core axis at its larger-diameter end (i.e., the right end). From left to right, the second-step blind hole includes a fifth and a sixth cylindrical hole, with the fifth cylindrical hole having a smaller diameter than the sixth. A feedback spring 4 is located within the feedback chamber 21, with one end resting against the bottom of the second-step blind hole and the other against the left side of the pilot valve core 9. Initially, this spring exerts a certain preload, ensuring that all valve ports remain tightly closed and leak-free. Furthermore, the spring 4 provides mechanical feedback between the main valve core 2 and the pilot valve core 9, allowing them to interact.

[0037] like Figure 5As shown, the main valve core 2 comprises, axially from left to right, a damping tail structure at the left end, a tapered section in the middle, and cylindrical sections 1 and 2 at the right end. The junction between cylindrical section 1 and the tapered section of the main valve core 2 forms a conical surface, forming the main valve port of the pilot high-flow balancing valve with the main valve sleeve 3. When the main valve core 2 is at the far left, a conical seal is formed between the junction between cylindrical section 1 and the tapered section of the main valve core 2 and the main valve sleeve 3, i.e., the main valve port is closed, and the backpressure chamber 23 and the load chamber 22 are disconnected. When the main valve core 2 moves to the right, the main valve port opens, connecting the backpressure chamber 23 and the load chamber 22, and the displacement of the main valve core 2 determines the opening degree of the main valve port. Two throttling grooves are symmetrically arranged at the rear end of the cylindrical outer circumference of the main valve core 2. These grooves comprise a U-shaped groove and a feedback throttling groove, arranged from left to right and interconnected. The feedback throttling groove is much smaller in depth and width than the U-shaped groove. The throttling grooves connect the load chamber 22 and the feedback chamber 21, and the end surfaces where the throttling grooves communicate with the feedback chamber 21 form the feedback valve port. Under the action of load pressure input from load port B, if the opening of the main valve core 2 is too large, the load chamber 22 and the feedback chamber 21 are connected through the throttling grooves. This creates a pressure differential, and the force generated by the interaction area pushes the main valve core 2 toward the closing direction of the main valve port, thereby achieving hydraulic limit when the load pressure is excessive, ensuring system safety.

[0038] like Figures 1-4 As shown, a second stepped through-hole is coaxially defined within the pilot valve sleeve 8. A pilot valve core 9 is coaxially mounted within the pilot valve sleeve 8, forming a sliding fit between the pilot valve core 9 and the pilot valve sleeve 8. The pilot valve core 9 and the main valve core 2 are coaxially arranged in opposite directions, with the larger diameter end of the pilot valve core 9 on the left and the smaller diameter end on the right. The smaller diameter end of the pilot valve core 9 passes through the pilot valve sleeve 8 and is inserted into the second cylindrical hole in the pilot valve body 10. The cavity between the smaller diameter end of the pilot valve core 9 and the pilot valve sleeve 8 forms a transition chamber 18. A cylindrical blind hole is defined at the left end of the pilot valve core 2, connecting the transition chamber 18 and the feedback chamber 21. An overcompensating damper 20 is installed in this cylindrical blind hole. A tapered section is provided at the smaller diameter end of the pilot valve core 9. This tapered section, together with the pilot valve sleeve 8, forms the pilot valve port of the pilot high-flow balancing valve.

[0039] A first annular groove is defined on the left side of the outer wall of the pilot valve sleeve 8, and two symmetrically distributed radial through holes are defined in the first annular groove to communicate with the feedback chamber 21. A first radial hole is defined on the inner wall of the main valve body 1 at a position corresponding to the first annular groove, connecting the feedback chamber 21 with the inlet end of the throttle valve core 7. A second annular groove is defined on the right side of the outer wall of the pilot valve sleeve 8, and several symmetrically distributed second radial holes are defined in the second annular groove to communicate with the transition chamber 18. A passage is defined within the pilot valve body 10 and the main valve body 1, one end of which communicates with the inlet end of the throttle valve core 7 and the other end communicates with the second annular groove, thereby connecting the feedback chamber 21 with the transition chamber 18 through the internal passage of the valve bodies and the inlet end of the throttle valve core 7. A third annular groove is defined on the central outer wall of the pilot valve sleeve 8, serving as the quick-closing chamber 19. Two symmetrically distributed radial through-holes are defined in the third annular groove, communicating with the cavity within the pilot valve body 10. An internal passage is defined within the main valve body 1 at a position corresponding to the third annular groove, connecting the quick-closing chamber 19 with the load chamber 22. When the pilot valve core 9 is in its initial position (i.e., when the pilot valve port is closed), the feedback chamber 21 is connected to the load chamber 22 via the quick-closing chamber 19 and the passage defined within the main valve body 1. When the pilot valve port is open, the quick-closing chamber 19 and the feedback chamber 21 are disconnected. An O-ring is installed on the pilot valve sleeve 8 between the first radial hole and the quick-closing chamber 19. O-rings are also used to seal the pilot valve sleeve 8 and the main valve body 1, as well as the pilot valve sleeve 8 and the pilot valve body 10, ensuring no leakage between the various chambers.

[0040] A cylindrical hole is radially defined within the pilot valve body 10 along the contact surface between the pilot valve body 10 and the pilot valve sleeve 8 (this contact surface is perpendicular to the axis). The axis of this cylindrical hole is perpendicular to the axis of the pilot valve body 10, forming a cavity between the pilot valve body 10 and the pilot valve sleeve 8, designated as a backpressure feedback chamber 24. When the pilot valve port is open, the backpressure feedback chamber 24 and the transition chamber 18 communicate through the pilot valve port. A backpressure feedback channel 26 is defined within the main valve body 1 and the pilot valve body 10. One end of this backpressure feedback channel 26 communicates with the backpressure feedback chamber 24 and the other end communicates with the backpressure chamber 23. A backpressure feedback damper 25 is installed within this backpressure feedback channel 26.

[0041] When the pilot valve core 9 is in its initial position, i.e., at the far right end, the pilot valve port is closed, a conical seal is formed between the pilot valve core 9 and the pilot valve sleeve 8, and the transition chamber 18 is disconnected from the back pressure feedback chamber 24. When the pilot valve core 9 moves to the left, the pilot valve port is opened, the transition chamber 18 is connected to the back pressure feedback chamber 24, and the displacement of the pilot valve core 9 determines the opening of the pilot valve port; at the same time, as the pilot valve core 9 moves, the cylindrical surface of the large diameter end of the pilot valve core 9 covers the quick closing chamber 19. At this time, there is no step gap between the pilot valve sleeve 8 and the pilot valve core 9, and the feedback chamber 21 is disconnected from the quick closing chamber 19.

[0042] An annular baffle 27 is coaxially fixedly attached to the first stepped through-hole defined within the pilot valve body 10, at a position within the third cylindrical hole near the second cylindrical through-hole. The annular baffle 27 is provided with a through-hole. The function of the annular baffle 27 is to prevent the pressure within the back-pressure feedback chamber 24 from affecting the force applied to the control piston 12. The control piston 12 is mounted in the first stepped through-hole, forming a sliding fit with the pilot valve body 10. The disc portion of the control piston 12 is located on the right side, abutting the control end cover 13. The shaft portion of the control piston 12 is located on the left side, coaxially mounted opposite the small-diameter end of the pilot valve core 9 within the through-hole within the annular baffle 27, forming a sliding fit between the control piston 12 and the pilot valve body 10. In the initial state, a gap exists between the shaft portion of the control piston 12 and the small-diameter end of the pilot valve core 9 to ensure that the initial position of the pilot valve core 9 is not affected by the control piston 12. The pilot control spring 11 is installed between the disc of the control piston 12 and the annular partition 27, with one end resting against the bottom of the third cylindrical hole (i.e., its leftmost end) and the other end resting against the control piston 12. Initially, the pilot control spring 11 exerts a certain preload, ensuring that the control piston 12 is in the closed position. In terms of dimensional design, the inner diameter of the third cylindrical hole matches the outer diameter of the pilot control spring 11 installed therein. The outer diameter of the annular partition 27 is smaller than the third cylindrical hole, and the spacing between the annular partition 27 and the third cylindrical hole matches the wall thickness of the pilot control spring 11. The diameter of the internal through-hole of the annular partition 27 matches the outer diameter of the small-diameter end of the control piston 12. The inner diameter of the fourth cylindrical hole matches the outer diameter of the disc of the control piston 12, enabling the control piston 12 to move axially. The cavity between the annular partition 27 of the pilot valve body 10 and the control piston 12 forms an oil drain chamber 17. An oil port is provided on the outer wall of the pilot valve body 10, connecting to the oil drain chamber 17. This port serves as the L port of the pilot high-flow balancing valve and is subsequently used for communication with the outside world. The right end of the control piston 12 is concave, and the conical cavity formed between it and the control end cover 13 serves as the pilot control chamber 15. An axial through-hole is provided on the end surface of the control end cover 13, connecting to the pilot control chamber 15. This through-hole serves as the X port of the pilot high-flow balancing valve, and a pilot inlet damper 14 is installed in this X port. A flow channel is provided within the control piston 12, connecting the pilot control chamber 15 to the oil drain chamber 17. An outlet damper 16 is installed in this flow channel; both the pilot inlet damper 14 and the outlet damper 16 act as pressure dividers.

[0043] A throttle valve mounting hole is defined on the side of the main valve body 1, where the pilot high-flow balancing valve port A is located. This throttle valve mounting hole communicates with the feedback chamber 21 via the first radial hole defined in the main valve body 1, the first annular groove defined in the pilot valve sleeve 8, and a radial through hole. The throttle valve assembly is installed in the throttle valve mounting hole. This plug-in throttle valve assembly comprises a throttle valve sleeve 5, a throttle end cap 6, and a throttle valve core 7. The throttle valve mounting hole is threaded on the inner periphery, and the throttle valve sleeve 5 has matching threads on its outer periphery. The throttle valve sleeve 5 is screwed into the throttle valve mounting hole, and an O-ring is installed in front of the threads to seal the throttle valve sleeve 5 against the main valve body 1. An axial through-hole is defined within the throttle valve sleeve 5, and a throttle end cap 6 is coaxially mounted within this axial through-hole. The two are sealed by an O-ring. A cavity is defined between the throttle valve sleeve 5 and the throttle end cap 6. A through-hole is defined on the sidewall of the throttle valve sleeve 5 corresponding to this cavity. This through-hole serves as the throttle valve port and communicates with the transition chamber 18 via an axial internal passage defined by the main valve body 1 and the pilot valve body 10, and a second radial hole defined on the right side of the pilot valve sleeve 8. A throttle valve core 7 is mounted within the coaxial axial through-hole defined within the throttle end cap 6, and an O-ring is used to seal the throttle valve core 7 and the throttle end cap 6. The bottom end (i.e., the inlet end) of the throttle valve core 7 passes through the bottom of the throttle valve sleeve 5 and communicates with the feedback chamber 21 via a first radial hole and a first annular groove. When the pilot valve core 9 is in the open state, due to the small flow area through the throttle valve core 7, a pressure difference is generated before and after the oil passing through the inlet and outlet of the throttle valve core 7, which generates a force to close the pilot valve core 9, thereby affecting the opening of the main valve port, ensuring the safety of the system when the load increases; when the flow area of ​​the throttle valve core 7 decreases, the pressure difference generated through the throttle valve core 7 is larger, the closing force acting on the pilot valve core 9 is also larger, and the flow enters the saturation state earlier than under the same load, realizing the over-compensation characteristic adjustment function of the pilot large flow balancing valve.

[0044] In the entire structure, the main valve core 2 is coaxial with the inner hole of the main valve sleeve 3, the pilot valve core 9 is coaxial with the inner hole of the pilot valve sleeve 8, the main valve core 2 and the pilot valve core 9 are coaxially arranged in opposite directions, and the small-diameter end of the control piston 12 is coaxially arranged opposite to the small-diameter end of the pilot valve core 9.

[0045] The dampers installed in the valve (including: the overcompensation damper 20 installed in the internal through hole of the pilot valve core 9, the outlet damper 16 installed in the internal channel of the control piston 12, the pilot inlet damper 14 installed in the channel connected to the control port X, and the back pressure feedback damper 25 installed in the back pressure feedback channel 26) are actually a sleeve structure with a small central through hole, which are screwed into the channel through threads.

[0046] In specific implementation, port A of the pilot high-flow balancing valve is connected to port A of the reversing valve, port B of the load is connected to the rodless chamber of the oil cylinder, port X is connected to the pressurized oil, and port L is connected to the oil tank. The overcompensating damper 20 installed inside the pilot valve core is replaced with a plug. This pilot high-flow balancing valve has three operating states: load increase, load hold, and load decrease. In each operating state, the specific operating conditions of each component of the pilot high-flow balancing valve are as follows:

[0047] Load rises: High-pressure oil is introduced through port A, correspondingly, back-pressure chamber 23 becomes a high-pressure chamber. Load port B and pilot control port X are depressurized, and pilot control chamber 15 is depleted of high-pressure oil. Pilot control spring 11 forces control piston 12 to remain stationary, compressing control end cap 13. Feedback spring 4 forces pilot valve core 9 rightward, forming a conical seal and keeping the pilot valve port closed. High-pressure oil in back-pressure chamber 23 acts on the left end of main valve core 2, overcoming the force of feedback spring 4 and pushing it rightward. The main valve port opens slightly, connecting port A to load port B. The damping tail structure on the left end of main valve core 2 effectively offsets the effects of hydraulic forces on main valve core 2, effectively improving its stability during opening.

[0048] Load hold: High-pressure oil is fed into load port B, correspondingly, load chamber 22 becomes a high-pressure chamber. No pressure oil is fed into port A and pilot control port X, correspondingly, no high-pressure oil is fed into pilot control chamber 15. Control piston 12, under the action of pilot control spring 11, presses against control end cap 13. Pilot valve core 9, under the action of feedback spring 4, remains compressed to the right, forming a conical seal, and the pilot valve port remains closed. Furthermore, main valve core 2, under the action of feedback spring 4, remains compressed to the left, forming a conical seal, and the main valve port remains closed. At this point, no conduction occurs between load port B, port A, and port L.

[0049] Load lowering: Figure 6 and Figure 7As shown, pressure is input to pilot control port X. High-pressure oil flows into pilot control chamber 15 through port X and pilot inlet damper 14, pushing control piston 12 to the left, overcoming the pressure of pilot control spring 11. This forces the oil in drain chamber 17 to flow out of port L into the tank, maintaining the pressure in drain chamber 17 at a low level. The shaft end of control piston 12 is mounted opposite the small-diameter end of pilot valve core 9. Initially, there is a gap between them, which in this embodiment is 0.5 mm. When control piston 12 moves leftward against the force of pilot control spring 11, after 0.5 mm of movement, the shaft of control piston 12 contacts the small-diameter end of pilot valve core 9, pushing the pilot valve core 9 to the left, overcoming the force of feedback spring 4, and opening the pilot valve port. At the same time, the oil in the rodless chamber of the oil cylinder enters the load port B. When the pilot valve port is opened, the high-pressure oil in the load chamber 22 flows into the feedback chamber 21 through the throttle groove opened on the main valve core 2, and the oil in the feedback chamber 21 flows into the transition chamber 18 through the throttle valve core 7; the oil in the transition chamber 18 flows into the back pressure feedback chamber 24 through the pilot valve port on the pilot valve core 9, and then flows into the back pressure chamber through the back pressure feedback channel 26 to realize oil return; at this time, the pressure in the feedback chamber 21 begins to drop, and due to the action of the throttle groove at the rear end of the main valve core 2, there is a pressure difference between the load chamber 22 and the feedback chamber 21, and under the action of the throttle valve core 7, there is a pressure difference between the feedback chamber 21 and the transition chamber 18. When the pressure in the feedback chamber 21 and the combined force of the feedback spring 4 are less than the pressure in the load chamber 22, the main valve core 2 is pushed to move to the right, the main valve port is opened, and the load port B is connected to the A port. When the pilot valve core 9 moves leftward, the cylindrical surface at the large-diameter end of the pilot valve core 9 covers the quick-closing chamber 19, disconnecting the feedback chamber 21 from the quick-closing chamber 19. When the pressures in the load chamber 22, the back-pressure chamber 23, the feedback chamber 21, and the force generated by the feedback spring 4 acting on the main valve core 2 reach equilibrium, the main valve core 2 maintains its balanced position, and a stable connection is established between the load port B and port A, executing the load lowering action. The main valve opening is also controlled by the pressure at the control port X. The higher the control pressure, the larger the main valve opening, achieving speed regulation during lowering.

[0050] Depending on the size of the throttle valve core 7's opening, the flow area is equivalent to a damping force equivalent to a sleeve orifice with a diameter of 1-2mm. As the oil passes through the throttle valve core 7, a pressure differential is generated between the feedback chamber 21 and the transition chamber 18, acting on the front and rear ends of the pilot valve core 9, forcing it to close. Compared to the state before the throttle valve assembly was installed, under the same control pressure X and load, the smaller the throttle valve core 7's opening, the greater the pressure differential generated across the pilot valve core 9. This, in turn, increases the force driving the pilot valve core 9 in the closing direction and reduces the saturation flow rate. This further advances the overcompensation inflection point, increases the overcompensation amount, and facilitates control of the lowering speed of the pilot high-flow balancing valve. By adjusting the opening size of the throttle valve core 7, the overcompensation characteristics of the pilot high-flow balancing valve can be adjusted.

[0051] The present invention has been simulated and verified by comparing the pilot large flow balancing valve with over-compensation adjustment function and the existing large flow balancing valve without adjustment function under the same conditions. Figure 8 As shown, the control pressure of the pilot large flow balancing valve is set to 14 bar, the load pressure is adjusted within the range of 0-300 bar, the displacement x of the throttle valve core 7 is adjusted, and the flow through the main valve core 2 is measured to obtain the over-compensation characteristic comparison curve of the throttle valve core 7 under different displacements. Figure 8 It can be seen that as the x-displacement decreases, the opening area of ​​the throttle valve core 7 decreases, the saturated flow decreases, the over-compensation inflection point is advanced, and the compensation amount increases, which verifies that the adjustment mechanism set in the present invention has an over-compensation adjustment effect on the pilot large-flow balancing valve, and has no negative impact on the overall performance of the balancing valve, ensuring the safety of the lowering action.

[0052] Traditional balancing valves usually only install an overcompensating damper 20 in the internal small hole of the pilot valve core 9. The high-pressure oil in the load port B returns to the L port through the load chamber 22, the feedback chamber 21, the transition chamber 18, and the oil drain chamber 17. A certain pressure difference is generated before and after the oil passes through the overcompensating damper 20, so that the pressure in the feedback chamber 21 is greater than that in the transition chamber 18. The resultant force acting on the pilot valve core 9 is in the closing direction of the pilot valve core 9. When the pressure in the load chamber 22 is greater, the flow rate passing through the overcompensating damper 20 is greater, and the resultant force acting on the pilot valve core 9 in the closing direction is also greater. Therefore, when the load of the existing large-flow balancing valve increases to a certain value, the main flow rate shows a downward trend. The inflection point here is called the overcompensation inflection point, and the flow rate here is called the saturation flow.

[0053] The present invention integrates the throttle valve function into the valve body. Specifically, the overcompensation damper 20 installed in the pilot valve core 9 is replaced with a plug. Under load-lowering conditions, the overcompensation characteristics of the pilot high-flow balancing valve are achieved through the throttle valve port, which connects the throttle valve assembly to the transition chamber 18. This allows the overcompensation characteristics and saturation flow rate to be adjusted by adjusting the opening area of ​​the throttle valve core 7. When subjected to significant load fluctuations, the pilot high-flow balancing valve designed in the present invention can enter a saturated state earlier, improving the balancing valve's resistance to shock and vibration, ensuring control characteristics under overload conditions. This has important engineering significance.

[0054] Those skilled in the art will understand that the foregoing descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art will still be able to modify the technical solutions described in the foregoing examples or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the invention shall be included within the scope of protection of the invention.

Claims

1. A pilot high flow balancing valve with over-compensation adjustment function, characterized in that: The main valve body comprises a main valve body, a pilot valve body, and a control end cover, which are arranged in sequence axially from front to back. An axial cavity is provided inside the main valve body and the pilot valve body and is interconnected. The main valve sleeve is arranged in the cavity inside the main valve body. An annular groove is provided on the inner wall corresponding to the middle of the main valve body and the main valve sleeve, forming a load cavity between the main valve body and the main valve sleeve. A load port B is provided on the main valve body to connect the outside with the load cavity. A plurality of radial through holes are provided in the middle of the main valve sleeve to connect the load cavity with the internal cavity of the main valve sleeve. The front end of the pilot valve sleeve is arranged in the cavity of the main valve body and is coaxially and tightly attached to the main valve sleeve, and the rear end thereof is arranged in the front part of the cavity inside the pilot valve body. The main valve core is coaxially slidably arranged in the cavity inside the main valve sleeve, and the pilot valve core is coaxially slidably arranged in the cavity inside the pilot valve sleeve; the main valve core and the pilot valve core are coaxially arranged in opposite directions, and the large diameter end of the main valve core is opposite to the large diameter end of the pilot valve core, and a feedback cavity is formed among the main valve core, the pilot valve core, the main valve sleeve and the pilot valve sleeve. A throttling groove is provided on the main valve core to connect the load cavity with the feedback cavity; one end of the feedback spring is against the large diameter end of the main valve core, and the other end is against the large diameter end of the pilot valve core; between the small diameter end of the main valve core and the main valve body The cavity is the back pressure cavity, and the main valve body is provided with an oil port A to connect the outside with the back pressure cavity; in the initial state of the balancing valve, the main valve core is located at the front end of the axial limit and forms a conical surface seal with the main valve sleeve, and the pilot valve core is located at the rear end of the axial limit and forms a conical surface seal with the pilot valve sleeve; the cavity between the small diameter end of the pilot valve core and the inside of the pilot valve sleeve forms a transition cavity; the throttle valve assembly is installed on the main valve body, and a channel is provided inside the main valve body to connect the cavity inside the throttle valve assembly with the feedback cavity and the transition cavity respectively; A back pressure feedback chamber is formed between the rear end of the pilot valve sleeve and the pilot valve body; a channel is provided in the pilot valve sleeve and the main valve body so that the load port B is connected to the feedback chamber in the initial state of the balancing valve, that is, when the pilot valve port is closed; when the pilot valve port is opened, the load port B is not connected to the feedback chamber, and the back pressure feedback chamber is connected to the transition chamber; a channel is provided inside the valve body to connect the back pressure feedback chamber with the back pressure chamber, and a damper is arranged in the channel; the control piston is coaxially arranged at the rear part of the cavity in the pilot valve body, and under the action of the pilot control spring, the control piston The disk of the plug is in contact with the control end cover and a pilot control chamber is left between the two; the small-diameter end of the pilot valve core passes through the pilot valve sleeve and is installed against the shaft of the control piston; the cavity between the control piston and the pilot valve body is the oil drain chamber, and the pilot valve body is provided with an oil port L to connect the outside with the oil drain chamber; the control end cover is provided with an X port to connect the outside with the pilot control chamber, and the pilot control chamber and the oil drain chamber are connected through a channel provided in the control piston, and dampers are arranged in the channel between the X port and the pilot control chamber and in the channel between the pilot control chamber and the oil drain chamber.

2. The pilot large flow balancing valve with over-compensation adjustment function according to claim 1 is characterized in that: A first annular groove is formed on the outer periphery of the pilot valve sleeve, and symmetrically distributed radial through holes are formed on the first annular groove to communicate with the feedback chamber; a throttle valve mounting hole is formed on the outer wall of the main valve body, and a first radial hole is formed on the inner wall of the main valve body at a position corresponding to the first annular groove to communicate with the throttle valve mounting hole; A throttle valve assembly is installed in the throttle valve mounting hole, and the assembly includes: a throttle valve sleeve, a throttle end cover, and a throttle valve core; a thread is provided on the inner circumference of the throttle valve mounting hole, and a thread matching the thread is provided on the outer circumference of the throttle valve sleeve, which is screwed into the throttle valve mounting hole, and the throttle valve sleeve and the main valve body are sealed; the throttle end cover is coaxially installed in a through hole coaxially opened inside the throttle valve sleeve, and the throttle end cover and the throttle valve sleeve are sealed; there is a cavity between the throttle valve sleeve and the throttle end cover, and a through hole is provided on the side wall of the throttle valve sleeve corresponding to the cavity as a throttle valve port, which is connected to the transition cavity through the axial internal channel opened by the main valve body and the pilot valve body, and the second radial hole opened on the rear side of the pilot valve sleeve; the throttle valve core is installed in the through hole coaxially opened inside the throttle end cover, and the throttle valve core and the throttle end cover are sealed; a through hole is provided at the bottom of the throttle valve sleeve to communicate with the first radial hole.

3. The pilot large flow balancing valve with over-compensation adjustment function according to claim 1 is characterized in that: The main valve core comprises, from front to back, a coaxial damping tail structure, a tapered section, and a cylindrical section. The main valve port of the pilot large-flow balancing valve is formed between the connection between the cylindrical section and the tapered section and the main valve sleeve. In the initial state of the balancing valve, the main valve core is located at the front end of the axial limit, and a conical surface seal is formed between the connection between the cylindrical section and the tapered section and the main valve sleeve. The main valve port is closed, and the back pressure chamber and the load chamber are not connected. When the main valve core moves backward, the main valve port is opened, and the back pressure chamber and the load chamber are connected. The throttling groove is symmetrically arranged at the tail end of the outer circumference of the cylindrical section of the main valve core. The throttling groove includes a U-shaped groove and a feedback throttling groove arranged in sequence from front to back and connected to each other, and the depth and width of the feedback throttling groove are both smaller than the U-shaped groove. The throttling groove is used to connect the load chamber and the feedback chamber, and the end surface where the throttling groove is connected to the feedback chamber forms a feedback valve port.

4. The pilot large flow balancing valve with over-compensation adjustment function according to claim 1 is characterized in that: A first stepped through hole is axially provided inside the pilot valve body, and the first stepped through hole comprises, from front to back, a first cylindrical hole, a second cylindrical hole, a third cylindrical hole, and a fourth cylindrical hole; The rear end of the pilot valve sleeve is installed in the first cylindrical hole. The first cylindrical hole is used to limit the pilot valve sleeve axially and radially. The inner diameter of the first cylindrical hole is the same as the outer diameter of the pilot valve sleeve, and the pilot valve sleeve and the first cylindrical hole are sealed by an O-ring. The inner diameter of the second cylindrical hole is adapted to the outer diameter of the small diameter end of the pilot valve core extending out of the outside of the pilot valve sleeve; an annular partition is coaxially fixedly connected to the position connected to the second cylindrical through hole in the third cylindrical hole, and a through hole adapted to the outer diameter of the shaft of the control piston is opened on the annular partition; the shaft of the control piston and the small diameter end of the pilot valve core are coaxially mounted opposite each other in the through hole inside the annular partition, and a gap is left between the shaft of the control piston and the small diameter end of the pilot valve core in the initial state of the balancing valve; the pilot control spring is installed between the disk of the control piston and the annular partition, one end of which rests against the front end of the third cylindrical hole, and the other end rests against the control piston; and the inner diameter of the third cylindrical hole is adapted to the outer diameter of the pilot control spring; the inner diameter of the fourth cylindrical hole is adapted to the outer diameter of the disk of the control piston.

5. The pilot large flow balancing valve with over-compensation adjustment function according to claim 1 is characterized in that: The main valve body and the pilot valve body, the main valve sleeve and the main valve body, the pilot valve sleeve and the main valve body, the pilot valve sleeve and the pilot valve body, and the main valve sleeve and the pilot valve sleeve are all sealed by O-type sealing rings.

6. The pilot high flow balancing valve with over-compensation regulating function according to claim 1 is characterized in that: A channel is provided in the pilot valve sleeve and the main valve body so that when the pilot valve port is closed, the load port B is connected with the feedback chamber. Specifically, an annular groove is provided on the outer wall of the middle portion of the pilot valve sleeve as a quick-closing chamber, and symmetrically distributed radial through holes are provided along the annular groove to connect the quick-closing chamber with the internal cavity of the pilot valve body. A channel is provided inside the main valve body to connect the quick-closing chamber with the load port B; and in the initial state of the balancing valve, the quick-closing chamber is connected with the feedback chamber. When the pilot valve port is opened, the channel between the quick-closing chamber and the feedback chamber is covered, and the quick-closing chamber and the feedback chamber are not connected.

7. The pilot high flow balancing valve with over-compensation regulating function according to claim 1 is characterized in that: The damper arranged in the back pressure feedback chamber and the back pressure chamber connecting channel, the damper arranged in the channel between the X port and the pilot control chamber, and the damper arranged in the channel between the pilot control chamber and the oil drain chamber are all sleeve structures with a small through hole opened on the axis, and are installed in each channel by threaded rotation.

8. The pilot high flow balancing valve with over-compensation regulating function according to claim 1 is characterized in that: A back pressure feedback chamber is formed between the rear end of the pilot valve sleeve and the pilot valve body. Specifically, a cylindrical hole is radially opened inside the pilot valve body along the contact surface of the pilot valve body and the pilot valve sleeve that is perpendicular to the axis, so that a cavity is formed between the pilot valve body and the pilot valve sleeve, which is recorded as the back pressure feedback chamber.

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