Balance valve, hydraulic control system and working machine

Abstract

The invention discloses a balance valve, a hydraulic control system and an operation machine. A valve cavity is formed in a valve body of the balance valve, and an oil inlet and an oil return opening are formed in the circumferential wall of the valve cavity; the valve element and the control piston are inserted into the valve cavity in a sliding mode from the two axial ends, the valve element comprises a first element body and a second element body which is inserted into the first element body in a sliding mode in the axial direction, and a first concave part and a second concave part which are arranged at intervals in the axial direction are formed in the peripheral wall of the first element body. A first cavity and a second cavity are respectively formed between the first concave part and the inner peripheral wall of the valve cavity and between the second concave part and the inner peripheral wall of the valve cavity, so that the overflowing area between the first core body and the valve cavity can be increased, and the oil inlet and the oil return port are respectively and correspondingly communicated with the first cavity and the second cavity; the driving end of the control piston penetrates through the first core body, the control piston and the second core body are coaxially and oppositely arranged in a spaced mode, and the control piston moves in the axial direction to drive the second core body to move in the axial direction and drive the first core body to move, so that oil in the first cavity and oil in the second cavity are communicated or blocked.

Description

Technical Field

[0001] This application belongs to the technical field of construction machinery, and particularly relates to a balance valve, a hydraulic control system and a construction machinery. Background Art

[0002] With the rapid development of construction machinery, users' requirements for crane operations are that the tonnage is getting larger and larger, and the oil passing capacity of hydraulic valves is getting higher. Especially for the telescopic cylinder, the flow demand is increasing. While meeting the flow demand, the requirements for the smoothness and controllability of the execution actions are getting higher and higher. The balance valve is a key hydraulic component of the load control system and the hydraulic load-bearing system. The performance of the balance valve directly affects the operation quality of the main engine. In the prior art, in order to enable the balance valve to have a larger oil passing capacity, the function of the valve sleeve is integrated on the valve body, so that it can feedback to the balance valve spool according to the change of the load under different flow conditions to achieve flow compensation. However, for the balance valve with this structure, under the same structural size, the valve sleeve occupies a part of the oil passing space, and the oil passing capacity is limited to a certain extent. Summary of the Invention

[0003] The purpose of this application is to provide a balance valve, a hydraulic control system and a construction machinery to solve the technical problem that the oil passing capacity between the spool and the valve body is limited.

[0004] To achieve the above purpose, on the one hand, this application provides a balance valve, including:

[0005] A valve body with a valve cavity inside, and an oil inlet and an oil return port are arranged on the peripheral wall of the valve cavity;

[0006] A spool is slidably inserted into the valve cavity from one axial end. The spool includes a first core body and a second core body slidably inserted into the first core body along the axis. First concave portions and second concave portions are formed on the outer peripheral wall of the first core body at intervals along the axis. A first cavity and a second cavity are respectively formed between the first concave portion and the second concave portion and the inner peripheral wall of the valve cavity. The oil inlet and the oil return port are respectively in corresponding communication with the first cavity and the second cavity;

[0007] A control piston is slidably inserted into the valve cavity from the other axial end. The driving end of the control piston penetrates through the first core body and is arranged coaxially and at intervals relative to the second core body. The axial movement of the control piston is used to drive the second core body to move axially and drive the first core body to follow, so that the oil in the first cavity and the second cavity is communicated or blocked.

[0008] In some embodiments, the valve cavity includes a first valve cavity and a second valve cavity that are sequentially communicated along the axial direction. The oil inlet and the oil return port are opened on the peripheral wall of the second valve cavity. A control oil port is opened on the peripheral wall of the first valve cavity. The hydraulic oil entering from the control oil port is used to apply an axial driving force to the control piston. The valve core is located in the second valve cavity. The control piston is arranged in the first valve cavity and is in sliding fit with the inner peripheral wall of the first valve cavity. The driving end of the control piston extends from the first valve cavity and is inserted into the first core body.

[0009] In some embodiments, a radially extending protrusion is provided on the inner peripheral wall of the second valve cavity. The first core body includes a first connection section, a second connection section, a third connection section, and a fourth connection section that are sequentially connected along the axial direction. A first concave portion is provided on the first connection section. A second concave portion is provided on the third connection section. The outer periphery of the second connection section is in sliding contact with the protrusion. The outer peripheral wall of the fourth connection section is in sliding contact with the inner peripheral wall of the second valve cavity.

[0010] In some embodiments, the radial cross-sectional area of the second connection section is smaller than that of the fourth connection section;

[0011] and / or,

[0012] A first throttle groove is provided on the outer periphery of the second connection section along the circumferential direction. The first throttle groove is located at a position where the second connection section is close to the first connection section. The groove depth of the first throttle groove gradually decreases in a direction away from the first connection section;

[0013] and / or,

[0014] A damping groove is provided on the outer periphery of the fourth connection section along the circumferential direction. The damping groove is located at a position where the fourth connection section is close to the third connection section. The groove depth of the damping groove gradually decreases in a direction away from the third connection section;

[0015] and / or,

[0016] A plurality of damping sections are further provided on the first connection section and are arranged at intervals along the circumferential direction. One end of each damping section is connected to the first connection section, and the other end is connected to the side of the second connection section facing the first connection section. A damping space is formed between the plurality of damping sections and the first connection section.

[0017] In some embodiments, the balancing valve also includes a first end cover arranged at one axial end of the valve body, a first flow channel is radially opened on the first end cover, an inclined hole connected to the first flow channel is opened on the valve body, a second flow channel connected to the first flow channel is axially opened on the first end cover, and a blocking member is provided at the intersection of the first flow channel and the second flow channel, and the movement of the blocking member can block or open the first flow channel under the action of hydraulic oil.

[0018] In some embodiments, a receiving groove connected to the second flow channel is provided on the side of the first end cover facing the first core body, a third cavity is formed between the first end cover and the side of the first core body facing away from the control piston, a first elastic member is connected between the end of the second core body facing away from the control piston and the first end cover, and the end of the first elastic member facing away from the second core body is accommodated in the receiving groove.

[0019] In some embodiments, the third connecting section is provided with a first connecting hole in the radial direction, the first core body is provided with a small diameter hole and a large diameter hole connected in sequence in the axial direction, the second core body includes a first small diameter portion, a large diameter portion and a second small diameter portion connected in sequence in the axial direction, the first small diameter portion is movably located in the small diameter hole, the large diameter portion and the second small diameter portion are both located in the large diameter hole, there is a gap between the second small diameter portion and the inner circumferential wall of the large diameter hole, and the large diameter portion can open or block the first connecting hole by moving axially so that the first connecting hole and the third cavity are connected or blocked.

[0020] In some embodiments, the large diameter portion and the second small diameter portion are axially penetrated by a second inner hole connected to the third cavity, an arcuate transition portion is connected between the first small diameter portion and the large diameter portion, the arcuate transition portion is provided with a through hole connected to the second inner hole, and an oil unloading groove extending axially is provided along the outer peripheral wall of the first small diameter portion.

[0021] In some embodiments, the control piston includes a piston cover, a piston rod, and a drive rod connected in sequence along the axial direction, the piston rod is located in the first valve cavity, and the drive rod passes through the side wall of the first valve cavity and is inserted into the small-diameter hole.

[0022] In some embodiments, the balancing valve includes a second end cover arranged at the other axial end of the valve body, a fourth cavity is formed inside the second end cover, a control oil port is provided on the inner wall of the first valve cavity, a connecting oil channel connecting the fourth cavity and the control oil port is provided on the second end cover, and a through opening connected to the fourth cavity is provided on the side of the valve body facing the second end cover, and the through opening is arranged corresponding to the end of the control piston away from the valve core.

[0023] In some embodiments, the communicating oil passage includes an axially communicating oil passage and a radially communicating oil passage that are sequentially communicated. One end of the axially communicating oil passage facing away from the radially communicating oil passage is communicated with the control oil port, and a first damper and a second damper are provided in the radially communicating oil passage.

[0024] The second aspect of the present application provides a hydraulic control system, including the balance valve as described above.

[0025] The third aspect of the present application provides a working machine, including the hydraulic control system as described above.

[0026] Through the above technical solutions, by setting the valve core into two inserted large-diameter first cores and a small-diameter second core, the outer peripheral wall of the first core and the inner peripheral wall of the valve cavity are in sliding fit, and a first inner concave portion and a second inner concave portion are formed at intervals on the outer peripheral wall of the first core, so as to increase the flow area between the first core and the valve cavity; and by controlling the axial drive of the control piston to apply an axial driving force to the second core, and then driving the first core to follow, it can make the oil in the first cavity and the second cavity communicate or be blocked, and finally realize the oil flow or blockage between the oil inlet and the oil return port. Since the flow area between the valve core and the valve body increases, the oil passing capacity of the oil between the two cavities can be improved. In addition, in the present application, since the valve sleeve on the valve core is cancelled, under the condition of the same structural size, the oil passing area is increased to meet the large-flow requirement, the number of key components is reduced, the processing difficulty is reduced, and the product consistency performance is improved.

[0027] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific embodiments section. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification. They are used together with the following specific embodiments to explain the embodiments of the present application, but do not constitute a limitation to the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts. In the drawings:

[0029] Figure 1 is a schematic structural diagram of the balance valve in the initial state of the first embodiment of the present application;

[0030] Figure 2 is a schematic structural diagram of the balance valve in the intermediate state of the first embodiment of the present application;

[0031] Figure 3 is a schematic structural diagram of the balance valve in the in-place state of the first embodiment of the present application;

[0032] Figure 4Schematic diagram of the internal hydraulic principle of the balance valve according to the first embodiment of the present application;

[0033] Figure 5 Schematic diagram of the structure of the first core in the balance valve of the present application;

[0034] Figure 6 Cross-sectional view schematic diagram of the first core in the balance valve of the present application;

[0035] Figure 7 Schematic diagram of the structure of the second core in the balance valve of the present application;

[0036] Figure 8 Cross-sectional view schematic diagram of the second core in the balance valve of the present application in the intermediate state;

[0037] Figure 9 Cross-sectional view schematic diagram of the second core in the balance valve of the present application in the in-place state;

[0038] Figure 10 Schematic diagram of the hydraulic principle of the hydraulic control system applied by the balance valve according to the first embodiment of the present application;

[0039] Figure 11 Schematic diagram of the structure of the balance valve according to the second embodiment of the present application in the initial state;

[0040] Figure 12 Schematic diagram of the hydraulic principle of the hydraulic control system applied by the balance valve according to the second embodiment of the present application;

[0041] Figure 13 Schematic diagram of the structure of the valve stem of the present application.

[0042] Explanation of reference numerals

[0043] 10. Valve body; 11. First valve cavity; 12. Second valve cavity; 13. Protrusion; 14. Tapered hole; A. Oil inlet; B. Oil return port; X. Control oil port; 20. Spool; 21. First core body; 211. First connection section; 212. Second connection section; 2121. First throttle groove; 213. Third connection section; 214. Fourth connection section; 2141. Damping groove; 215. Damping section; 216. First communication hole; 217. Small-diameter hole; 218. Large-diameter hole; 22. Second core body; 221. First small-diameter part; 222. Large-diameter part; 223. Second small-diameter part; 224. Arc transition part; 225. Second inner hole; 226. Through hole; 227. Oil discharge groove; 23. First cavity; 24. Second cavity; 30. Control piston; 31. Piston cover; 32. Piston rod; 33. Driving rod; 34. Third elastic member; 40. First end cover; 41. First flow channel; 42. Second flow channel; 43. Sealing member; 44. Third cavity; 45. First elastic member; 50. Second end cover; 51. Fourth cavity; 52. Axial communication oil channel; 53. Radial communication oil channel; 54. First damping; 55. Second damping; 56. Valve rod; 57. Valve sleeve; 58. Second elastic member; 59. Second throttle groove; 100. Balance valve; 200. Telescopic oil cylinder; 300. Motor. Detailed implementation manners

[0044] The following describes in detail the specific implementation manners of the present application with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0045] The balance valve, hydraulic control system and working machine according to the present application will be described below with reference to the accompanying drawings.

[0046] As Figures 1 to 4 shown, the present application provides a balance valve 100, including a valve body 10, a spool 20 and a control piston 30; the interior of the valve body 10 has a valve cavity, and an oil inlet A and an oil return port are provided on the peripheral wall of the valve cavity; the spool 20 is slidably inserted into the valve cavity from one axial end, the spool 20 includes a first core body 21 and a second core body 22 slidably inserted into the first core body 21 along the axis, a first concave portion and a second concave portion are formed on the outer peripheral wall of the first core body 21 and arranged at intervals along the axis, a first cavity 23 and a second cavity 24 are respectively formed between the first concave portion and the second concave portion and the inner peripheral wall of the valve cavity, and the oil inlet A and the oil return port B are respectively corresponding and communicated with the first cavity 23 and the second cavity 24; the control piston 30 is slidably inserted into the valve cavity from the other axial end, the driving end of the control piston 30 penetrates through the first core body 21 and is arranged coaxially and relatively spaced from the second core body 22, and the axial movement of the control piston 30 is used to drive the second core body 22 to move axially and drive the first core body 21 to follow, so that the oil in the first cavity 23 and the second cavity 24 is communicated or blocked.

[0047] Compared with the structure of the prior art in which the valve sleeve 57 is mounted on the valve core 20, in this embodiment, the valve core 20 is arranged to be two inserted large-diameter first core bodies 21 and small-diameter second core bodies 22, the outer peripheral wall of the first core body 21 and the inner peripheral wall of the valve cavity are slidably matched, and first inner recesses and second inner recesses arranged at intervals are formed on the outer peripheral wall of the first core body 21, thereby increasing the flow area between the first core body 21 and the valve cavity; and by controlling the axial drive of the piston 30 to apply an axial driving force to the second core body 22, thereby driving the first core body 21 to follow, the oil in the first cavity 23 and the second cavity 24 can be connected or blocked, and finally the oil flow or blockage of the oil inlet A and the oil return port B is achieved. Since the flow area between the valve core 20 and the valve body 10 is increased, the oil flow capacity between the two cavities can be improved. In addition, since the valve sleeve 57 on the valve core 20 is eliminated in the present application, the second core body 22 having the function of the valve sleeve 57 is integrated into the first core body 21, thereby reducing the number of key components. While reducing the valve sleeve 57 under the same aperture, it can provide a greater oil flow capacity, reduce the processing difficulty, and improve the product consistency performance.

[0048] In some embodiments, the valve cavity includes a first valve cavity 11 and a second valve cavity 12 which are connected in sequence along the axial direction. The oil inlet A and the oil return port are both opened on the peripheral wall of the second valve cavity 12. A control oil port X is opened on the peripheral wall of the first valve cavity 11. The hydraulic oil entering from the control oil port X is used to apply an axial driving force to the control piston 30. The valve core 20 is located in the second valve cavity 12. The control piston 30 is arranged in the first valve cavity 11 and slides with the inner peripheral wall of the first valve cavity 11. The driving end of the control piston 30 extends from the first valve cavity 11 and is inserted into the first core body 21.

[0049] In this embodiment, when the hydraulic oil enters the control oil port X, the hydraulic oil can apply a left axial driving force to the end of the control piston 30 away from the valve core 20, so as to drive the control piston 30 to move axially along the first valve chamber 11; the end of the control piston 30 facing the valve core 20 is located in the second valve chamber 12 and inserted into the first core body 21, and as it moves to the right, it can abut the second core body 22 and apply a right axial driving force to the second core body 22, so that the second core body 22 can move axially to the right, thereby realizing oil communication between the first cavity 23 and the second cavity 24.

[0050] like Figure 5 and Figure 6As shown, a radially extending protrusion 13 is provided on the inner peripheral wall of the second valve cavity 12. The first core body 21 includes a first connecting section 211, a second connecting section 212, a third connecting section 213, and a fourth connecting section 214 that are sequentially connected along the axial direction. The first connecting section 211 has a first concave portion, and the third connecting section 213 has a second concave portion. The outer periphery of the second connecting section 212 is in sliding contact with the protrusion 13, and the outer peripheral wall of the fourth connecting section 214 is in sliding contact with the inner peripheral wall of the second valve cavity 12. In this embodiment, the position where the protrusion 13 and the second connecting section 212 are in sliding contact can divide the second valve cavity 12 into a first cavity 23 and a second cavity 24. Since the outer peripheral wall of the fourth connecting section 214 is in sliding contact with the inner peripheral wall of the second valve cavity 12, the second cavity 24 can be blocked, realizing the sealing connection between the outer peripheral wall of the fourth connecting section 214 and the inner peripheral wall of the second valve cavity 12. When the entire valve core 20 moves axially, the relative positions of the protrusion 13 and the second connecting section 212 change, and the relative positions of the fourth connecting section 214 and the inner peripheral wall of the second valve cavity 12 also change, so that the first cavity 23 and the second cavity 24 can be connected or disconnected.

[0051] In some embodiments, the radial cross-sectional area of the second connecting section 212 is smaller than that of the fourth connecting section 214. In this embodiment, by designing the second connecting section 212 and the fourth connecting section 214 of the first core body 21 to have an area difference structure, the first core body 21 can also be driven to move to the right according to the oil pressure at the oil return port B and the pressure difference on the right side of the first core body 21. Specifically, since the radial cross-sectional area of the second connecting section 212 is smaller than that of the fourth connecting section 214, the leftward acting force exerted by the hydraulic oil at the oil return port B on the second connecting section 212 is smaller than the rightward acting force exerted on the fourth connecting section 214. Thus, the acting force on the first core body 21 is to the right, which can drive the first core body 21 to move to the right. When the first core body 21 moves to the right, the relative positions of the second connecting section 212 and the protrusion 13 change and form a gap, so that the second cavity 24 communicates with the first cavity 23 through the gap between the protrusion 13 and the second connecting section 212.

[0052] In some embodiments, a first throttling groove 2121 is circumferentially formed on the outer periphery of the second connecting section 212. The first throttling groove 2121 is located at a position where the second connecting section 212 is close to the first connecting section 211, and the groove depth of the first throttling groove 2121 gradually decreases in the direction away from the first connecting section 211. As Figure 1 shown, when the valve core 20 is in the initial position, the hydraulic oil entering from the oil inlet A flows into the oil return port B corresponding to the second cavity 24 through the first cavity 23. As Figure 2As shown, when the balance valve 100 operates, the second connection section 212 abuts against the protrusion 13 at the rightmost end, so that there is no gap between the protrusion 13 and the second connection section 212, so as to block the first cavity 23 and the second cavity 24. During the process of the first core 21 being pushed to move rightward under the action of the pressure difference, due to the existence of the first throttling groove 2121, a gap equal to the groove depth of the first throttling groove 2121 is formed between the protrusion 13 and the second connection section 212. This gap shows a decreasing trend in the direction away from the first connection section 211. In this way, the hydraulic oil at the oil return port B can flow from the second cavity 24 along the gap between the protrusion 13 and the second connection section 212 to the first cavity 23, and then realize the oil flow from the oil return port B to the oil inlet A. Since the groove depth of the first throttling groove 2121 gradually decreases in the direction away from the first connection section 211, different flow rate requirements can be met when the relative displacement between the second connection section 212 and the protrusion 13 is different. That is, the demand for small and delicate flow rate is met when the opening is small, and the demand for large flow rate is met when the opening is full.

[0053] In some embodiments, a damping groove 2141 is circumferentially formed on the outer periphery of the fourth connection section 214. The damping groove 2141 is located at a position where the fourth connection section 214 is close to the third connection section 213, and the groove depth of the damping groove 2141 gradually decreases in the direction away from the third connection section 213. When the first core 21 moves rightward under the action of the pressure difference, the portion with a gap between the fourth connection section 214 and the inner peripheral wall of the second valve cavity 12 gradually increases, so as to balance the pressures on both sides of the fourth connection section 214. Moreover, the oil pressures in the second cavity 24 and the first cavity 23 are gradually balanced, and then the compensation effect of the load flow rate is realized.

[0054] In some embodiments, a plurality of damping sections 215 are arranged at intervals along the circumferential direction on the first connection section 211. One end of each damping section 215 is connected to the first connection section 211, and the other end is connected to the side of the second connection section 212 facing the first connection section 211. A damping space is formed between the plurality of damping sections 215 and the first connection section 211. In this embodiment, when the hydraulic oil in the first cavity 23 enters the second cavity 24 or the hydraulic oil in the second cavity 24 enters the first cavity 23, the existence of the damping sections 215 can reduce the flow rate of the hydraulic oil and play a certain resistance role on the hydraulic oil, ensuring the stability when the balance valve 100 works.

[0055] In some embodiments, the balancing valve 100 also includes a first end cover 40 arranged at one axial end of the valve body 10, a first flow channel 41 is radially opened on the first end cover 40, an inclined hole 14 connected to the first flow channel 41 is opened on the valve body 10, the inclined hole 14 connects the first end cover 40 and the valve body 10, a second flow channel 42 connected to the first flow channel 41 is axially opened on the first end cover 40, a blocking member 43 is provided at the intersection of the first flow channel 41 and the second flow channel 42, the blocking member 43 can move at the intersection of the first flow channel 41 and the second flow channel 42, and the movement of the blocking member 43 can block or open the first flow channel 41 under the action of hydraulic oil.

[0056] In some embodiments, a receiving groove connected to the second flow channel 42 is provided on the side of the first end cover 40 facing the first core 21, and a third cavity 44 is formed between the first end cover 40 and the side of the first core 21 facing away from the control piston 30. A first elastic member 45 is connected between the end of the second core 22 facing away from the control piston 30 and the first end cover 40, and the end of the first elastic member 45 facing away from the second core 22 is accommodated in the receiving groove.

[0057] The blocking member 43 may be a steel ball. Figure 1 As shown, when the hydraulic oil from the oil inlet A flows to the second cavity 24 through the first cavity 23, the hydraulic oil in the third cavity 44 flows to the second flow channel 42, so that the hydraulic oil exerts a rightward driving force on the steel ball, so that the first flow channel 41 and the second flow channel 42 are connected, and the hydraulic oil in the third cavity 44 flows out of the inclined hole 14 through the first flow channel 41. Figure 3 As shown, when returning oil, a portion of the external hydraulic oil flows to the first flow channel 41 through the inclined hole 14, thereby exerting an axial driving force to the left on the steel ball to drive the steel ball to move to the left and block the second flow channel 42; at this time, the hydraulic oil in the third cavity 44 flows to the first cavity 23 through the inner hole of the valve core 20, thereby achieving oil balance.

[0058] In addition, a first elastic member 45 is connected between the second core 22 and the first end cover 40. When the second core 22 moves to the right, the presence of the first elastic member 45 can play a buffering role to prevent the second core 22 from moving quickly and causing jitter and stalling of the cylinder or motor during operation; when the hydraulic oil in the third cavity 44 flows to the first cavity 23 through the inner hole of the valve core 20, the first elastic member 45 restores its deformation to drive the second core 22 to move to the left.

[0059] In some embodiments, the third connecting section 213 is provided with a first communication hole 216 in the radial direction. The first core body 21 is axially provided with a small-diameter hole 217 and a large-diameter hole 218 that are sequentially communicated. The second core body 22 includes a first small-diameter portion 221, a large-diameter portion 222, and a second small-diameter portion 223 that are sequentially connected in the axial direction. The first small-diameter portion 221 is movably located in the small-diameter hole 217, and both the large-diameter portion 222 and the second small-diameter portion 223 are located in the large-diameter hole 218. There is a gap between the second small-diameter portion 223 and the inner peripheral wall of the large-diameter hole 218. The large-diameter portion 222 can open or block the first communication hole 216 by moving axially, so that the first communication hole 216 is communicated with or blocked from the third cavity 44. As Figure 1 , Figure 2 and Figure 8 shown, in the initial state and the intermediate state, the second core body 22 is located at the left position. At this time, the second small-diameter portion 223 corresponds to the position of the first communication hole 216. Since there is a gap between the second small-diameter portion 223 and the inner peripheral wall of the large-diameter hole 218, the first communication hole 216 is opened in this way, and the third cavity 44 is communicated with the second cavity 24 through the first communication hole 216. When the hydraulic oil at the oil inlet A flows towards the oil return port B, a part of the hydraulic oil in the second cavity 24 enters the third cavity 44 through the first communication hole 216 to apply a driving force to the right on the blocking member 43. As Figure 3 and Figure 9 shown, when the second core body 22 moves to the right, the large-diameter portion 222 can block the first communication hole 216. The hydraulic oil in the second cavity 24 flows to the first cavity 23, and at the same time, the hydraulic oil in the third cavity 44 flows to the first cavity 23 through the inner hole.

[0060] In some embodiments, as Figure 7 shown, the large-diameter portion 222 and the second small-diameter portion 223 are axially provided with a second inner hole 225 communicated with the third cavity 44. An arc-shaped transition portion 224 is connected between the first small-diameter portion 221 and the large-diameter portion 222. The arc-shaped transition portion 224 is provided with a through hole 226 communicated with the second inner hole 225. The outer peripheral wall of the first small-diameter portion 221 is provided with an oil discharge groove 227 extending in the axial direction. As Figure 3 shown, when performing flow balance compensation, the hydraulic oil in the third cavity 44 flows into the through hole 226 of the arc-shaped transition portion 224 through the second inner hole 225, then flows out from the through hole 226 to the oil discharge groove 227 on the first small-diameter portion 221, and flows leftward along the oil discharge groove 227. Since there is a gap between the first small-diameter portion 221 and the inner peripheral wall of the small-diameter hole 217, the hydraulic oil flows through this gap to the first cavity 23, thereby realizing the oil fluid communication between the third cavity 44 and the first cavity 23.

[0061] To further facilitate the understanding of the technical solution of the present application, the following details three states of the oil fluid flow:

[0062] As Figure 1 shown, in the initial state, the pressure oil entering from the oil inlet A acts on the left side of the second connection section 212 of the first core 21, driving the second core 22 to move to the right. The hydraulic oil in the third cavity 44 drives the steel ball to move to the right, thereby connecting the first flow channel 41 and the second flow channel 42, realizing the flow of oil A - B. As Figure 1 shown by the arrow, it is the flow direction of the hydraulic oil. The pressure oil at the oil return port B flows to the third cavity 44 through two positions of the first communication hole 216 and the damping groove 2141 until the oil pressure in the second cavity 24 is equal to the oil pressure in the third cavity 44. The first core 21 receives a force to the left, playing a role in load holding.

[0063] As Figure 2 and Figure 3 shown, the hydraulic oil entering from the control oil port X passes through the first damper 54, and a part of the oil passes through the second damper 55 to obtain an effectively controlled pressure oil and flows into the fourth cavity 51, pushing the control piston 30 to move to the right, thereby pushing the second core 22 to move to the right. The first communication hole 216 at the position 1.21 between the second core 22 and the first core 21 is closed, so that the pressure oil in the third cavity 44 on the right side of the first core 21 is discharged to the first cavity 23 through the first inner hole and the oil discharge groove 227 of the second core 22, and flows to the oil inlet A through the first cavity 23, reducing the pressure in the third cavity 44. When the oil pressure in the third cavity 44 is less than the oil pressure in the second cavity 24, the first core 21 receives a force to the right under the action of the hydraulic oil in the second cavity 24, causing the first core 21 to move to the right, so that the oil flows from the oil return port B to the oil inlet A. The position of the first core 21 is determined by the pressure in the third cavity 44, and the pressure in the third cavity 44 is determined by the damping groove 2141 on the fourth connection section 214 according to the oil inlet speed. The oil discharge speed of the second core 22 is determined by the size of the oil discharge groove 227 on the second core 22, thus realizing the function of automatic flow compensation.

[0064] In some embodiments, the control piston 30 includes a piston cap 31, a piston rod 32, and a driving rod 33 connected in sequence along the axial direction. The piston rod 32 is located in the first valve cavity 11, and the driving rod 33 penetrates the side wall of the first valve cavity 11 and is inserted into the small-diameter hole 217. A second elastic member 58 is also wound around the piston rod 32. By providing the second elastic member 58, the movement of the piston rod 32 is buffered to prevent the piston rod 32 from moving too fast and causing jitter.

[0065] In some embodiments, the balance valve 100 includes a second end cap 50 provided at the other axial end of the valve body 10. A fourth cavity 51 is formed inside the second end cap 50. A control oil port X is opened on the inner wall of the first valve cavity 11. A communication oil passage communicating the fourth cavity 51 and the control oil port X is opened on the second end cap 50. A through port communicating with the fourth cavity 51 is opened on the side of the valve body 10 facing the second end cap 50. The through port corresponds to the end of the control piston 30 facing away from the valve core 20. In this embodiment, by providing the second end cap 50, the side of the first valve cavity 11 facing away from the second valve cavity 12 is closed, and by providing a communication oil passage communicating with the empty control oil port X on the second end cap 50, hydraulic oil entering from the control oil port X can exert a driving force on the control piston 30 through the communication oil passage and the through port, thereby realizing the oil fluid communication between the oil inlet A and the oil return port.

[0066] In some embodiments, the communication oil passage includes an axially communicating oil passage 52 and a radially communicating oil passage 53 that are sequentially communicated. One end of the axially communicating oil passage 52 facing away from the radially communicating oil passage 53 is communicated with the control oil port X. A first damper 54 and a second damper 55 are provided in the radially communicating oil passage 53. Among them, both the first damper 54 and the second damper 55 can be filter meshes. The first damper 54 is an oil inlet damper, and the second damper 55 is a pressure dividing damper.

[0067] In this embodiment, when the oil cylinder starts to retract, when the control oil enters the control oil port X, after passing through the first damper 54 and the second damper 55, pressure oil is formed in the fourth cavity 51, pushing the control piston 30 to move to the right, thereby pushing open the second core body 22, and enabling the pressure in its third cavity 44 to flow out through the second inner hole 225 of the second core body 22 and the first inner hole of the first core body 21, reducing the pressure in its third cavity 44. A pressure difference is formed between the two ends (the first cavity 23 and the third cavity 44) of the first core body 21, so that the first core body 21 moves by itself according to the pressure difference between the two, thereby realizing a large-flow output from the oil return port B to the oil inlet A.

[0068] Moreover, in this embodiment, by providing the axially communicating oil passage 52 and the radially communicating oil passage 53 that are sequentially communicated on the second end cap 50, the design of pipelines is reduced, and the structure of the entire balance valve 100 is simplified.

[0069] In addition, the control oil port X, the axially communicating oil passage 52, and the radially communicating oil passage 53 of the present application together form a pilot control oil circuit. By providing a damping network on the pilot control oil circuit, the flow impact caused by the pressure impact of the control pressure oil is reduced, enabling it to retract smoothly, and effectively preventing the balance valve 100 from jittering during the movement process.

[0070] In addition, a valve rod 56 is further provided inside the second end cap 50, as Figure 13As shown, a second throttle groove 59 is provided on the valve stem 56, and a valve sleeve 57 is provided on the valve stem 56. The hydraulic oil entering from the control oil port X passes through the radial communication oil passage 53 and the axial communication oil passage 52 and enters the second throttle groove 59 on the valve stem 56, and then flows to the fourth cavity 51. In the initial state, the area of the fourth cavity 51 between the end of the valve stem 56 and the control piston 30 is the largest. As the control piston 30 moves to the right, the area of the fourth cavity 51 gradually decreases and tends to be 0, and finally it is the cross-sectional area of the second throttle groove 59. All the hydraulic oil applies a driving force to the control piston 30 to drive the control piston 30 to move to the right.

[0071] Further, in the second embodiment, as Figure 11 For Figure 1 a schematic cross-sectional view from a different perspective in the first embodiment. Among them, the difference between the first embodiment and the second embodiment is that, on the basis of the first embodiment, an oil drain port L is opened on the second end cover 50 in the second embodiment. The oil drain port L is directly communicated with the fuel tank. That is to say, the control oil port X and the oil drain port L are opened on the second end cover 50 in the second embodiment, while only the control oil port X is opened on the second end cover 50 in the first embodiment.

[0072] The first embodiment can be applied to the telescopic oil cylinder 200. As Figure 10 shown, in the hydraulic control oil circuit of the oil cylinder, since the oil inlet of the control oil port X relies on an additional oil circuit, the control pressure of the control oil port X is mainly affected by the external oil supply circuit. When the control piston 30 moves, it is necessary to discharge the hydraulic oil in the cavity where the second elastic member 58 is located through the oil inlet A. At this time, the hydraulic oil is directly discharged to the oil inlet A;

[0073] The second embodiment can be applied to the motor 300. As Figure 12 shown, the control oil of the control oil port X comes from the oil circuit where the oil inlet A and the oil return port B are located. The hydraulic oil in the cavity where the second elastic member 58 is located is directly discharged to the oil drain port L and flows to the fuel tank, so that the control pressure of the control oil port X is not affected by the load pressure of the oil inlet A.

[0074] The second aspect of the present application provides a hydraulic control system, including the balance valve 100 as described above. Since this hydraulic control system adopts all the embodiments of the above balance valve 100, it has all the beneficial effects brought by the above balance valve 100, which will not be elaborated here one by one. As Figure 10 and Figure 12 shown, this balance valve 100 is provided on the working oil circuit of the operation valve and the telescopic oil cylinder 200. Through the oil pressure balance function of the balance valve 100, the telescopic oil cylinder 200 is prevented from jittering and stalling during operation.

[0075] A third aspect of the present application provides a construction machine, including the hydraulic control system as described above. Among them, the construction machine can be a crane or the like. Since the construction machine adopts all the embodiments of the above-mentioned hydraulic control system, it has all the beneficial effects brought by the above-mentioned hydraulic control system, which will not be enumerated one by one here.

[0076] In the description of the present application, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0077] In the present application, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to", "fixed" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0078] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0079] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as a limitation to the present application. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A balance valve, characterized in that, Comprising: A valve body (10) having a valve cavity inside, and an oil inlet (A) and an oil return port (B) are formed on the peripheral wall of the valve cavity; A valve core (20) is slidably inserted into the valve cavity from one axial end. The valve core (20) includes a first core body (21) and a second core body (22) slidably inserted into the first core body (21) along the axis. A first concave portion and a second concave portion are formed on the outer peripheral wall of the first core body (21) and arranged at intervals along the axis. A first cavity (23) and a second cavity (24) are respectively formed between the first concave portion and the second concave portion and the inner peripheral wall of the valve cavity. The oil inlet (A) and the oil return port (B) are respectively in corresponding communication with the first cavity (23) and the second cavity (24); A control piston (30) is slidably inserted into the valve cavity from the other axial end. The driving end of the control piston (30) penetrates through the first core body (21) and is arranged coaxially and at an interval relative to the second core body (22). The axial movement of the control piston (30) is used to drive the second core body (22) to move axially and drive the first core body (21) to follow, so that the oil in the first cavity (23) and the second cavity (24) is communicated or blocked.

2. The balance valve according to claim 1, characterized in that, The valve cavity includes a first valve cavity (11) and a second valve cavity (12) which are sequentially communicated along the axis. The oil inlet (A) and the oil return port are formed on the peripheral wall of the second valve cavity (12). A control oil port (X) is formed on the peripheral wall of the first valve cavity (11). The hydraulic oil entering from the control oil port (X) is used to apply an axial driving force to the control piston (30). The valve core (20) is located in the second valve cavity (12). The control piston (30) is arranged in the first valve cavity (11) and is slidably matched with the inner peripheral wall of the first valve cavity (11). The driving end of the control piston (30) extends from the first valve cavity (11) and is inserted into the first core body (21).

3. The balance valve according to claim 2, wherein A protrusion (13) extending radially is provided on the inner peripheral wall of the second valve cavity (12). The first core body (21) includes a first connection section (211), a second connection section (212), a third connection section (213), and a fourth connection section (214) which are sequentially connected along the axis. The first connection section (211) has a first concave portion, and the third connection section (213) has a second concave portion. The outer periphery of the second connection section (212) is in sliding contact with the protrusion (13), and the outer peripheral wall of the fourth connection section (214) is in sliding contact with the inner peripheral wall of the second valve cavity (12).

4. The balance valve according to claim 3, characterized in that, The radial cross-sectional area of the second connection section (212) is smaller than the radial cross-sectional area of the fourth connection section (214); And / or A first throttle groove (2121) is circumferentially formed on the outer periphery of the second connection section (212). The first throttle groove (2121) is located at a position where the second connection section (212) is close to the first connection section (211). The groove depth of the first throttle groove (2121) gradually decreases in a direction away from the first connection section (211). and / or A damping groove (2141) is circumferentially formed on the outer periphery of the fourth connection section (214). The damping groove (2141) is located at a position where the fourth connection section (214) is close to the third connection section (213). The groove depth of the damping groove (2141) gradually decreases in a direction away from the third connection section (213). and / or A plurality of damping sections (215) are arranged at intervals along the circumference on the first connection section (211). One end of each damping section (215) is connected to the first connection section (211), and the other end is connected to a side of the second connection section (212) facing the first connection section (211). A damping space is formed between the plurality of damping sections (215) and the first connection section (211).

5. The balance valve according to claim 3, characterized in that, The balance valve further includes a first end cap (40) provided at an axial end of the valve body (10). A first flow passage (41) is radially formed on the first end cap (40). An inclined hole (14) communicating with a part of the first flow passage (41) is formed on the valve body (10). A second flow passage (42) communicating with the first flow passage (41) is axially formed on the first end cap (40). A blocking member (43) is provided at a position where the first flow passage (41) and the second flow passage (42) meet. The movement of the blocking member (43) can block or open the first flow passage (41) under the action of hydraulic oil.

6. The balance valve according to claim 5, characterized in that, A receiving groove communicating with the second flow passage (42) is provided on a side of the first end cap (40) facing the first core body (21). A third cavity (44) is formed between the first end cap (40) and a side of the first core body (21) facing away from the control piston (30). A first elastic member (45) is connected between an end of the second core body (22) facing away from the control piston (30) and the first end cap (40). One end of the first elastic member (45) facing away from the second core body (22) is received in the receiving groove.

7. The balance valve according to claim 6, characterized in that, The third connecting section (213) is provided with a first communication hole (216) in the radial direction. The first core body (21) is axially provided with a small-diameter hole (217) and a large-diameter hole (218) that are sequentially communicated. The second core body (22) includes a first small-diameter portion (221), a large-diameter portion (222), and a second small-diameter portion (223) that are sequentially connected in the axial direction. The first small-diameter portion (221) is movably located in the small-diameter hole (217), and both the large-diameter portion (222) and the second small-diameter portion (223) are located in the large-diameter hole (218). There is a gap between the second small-diameter portion (223) and the inner peripheral wall of the large-diameter hole (218). The large-diameter portion (222) can open or block the first communication hole (216) by moving axially, so that the first communication hole (216) is communicated with or blocked from the third cavity (44).

8. The balance valve according to claim 7, characterized in that, The large-diameter portion (222) and the second small-diameter portion (223) are axially provided with a second inner hole (225) that communicates with the third cavity (44). An arc-shaped transition portion (224) is connected between the first small-diameter portion (221) and the large-diameter portion (222). The arc-shaped transition portion (224) is provided with a through hole (226) that communicates with the second inner hole (225). An oil discharge groove (227) extending in the axial direction is provided on the outer peripheral wall of the first small-diameter portion (221).

9. The balance valve according to any one of claims 2 to 8, characterized in that, The balance valve includes a second end cover (50) provided at the other axial end of the valve body (10). A fourth cavity (51) is formed inside the second end cover (50). A communication oil passage communicating the fourth cavity (51) and the control oil port (X) is provided on the second end cover (50). A through port communicating with the fourth cavity (51) is provided on the side of the valve body (10) facing the second end cover (50). The through port is provided corresponding to the end of the control piston (30) facing away from the valve core (20).

10. The balance valve according to claim 9, characterized in that, The communication oil passage includes an axially communicating oil passage (52) and a radially communicating oil passage (53) that are sequentially communicated. One end of the axially communicating oil passage (52) facing away from the radially communicating oil passage (53) is communicated with the control oil port (X). A first damper (54) and a second damper (55) are provided in the radially communicating oil passage (53).

11. A hydraulic control system, characterized in that, Comprising the balance valve according to any one of claims 1 to 10.

12. An operating machine, characterized in that, Comprising the hydraulic control system according to claim 11.

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