Three-position high-pressure hydraulic direction switching valve

Abstract

The invention discloses a three-position high-pressure hydraulic direction switching valve, and belongs to the technical field of hydraulic reversing valves, the three-position high-pressure hydraulic direction switching valve comprises a valve sleeve, a valve body, shaft end covers, inner shaft cylinders, pilot valves and electromagnetic coils, the center of the valve body is fixed in the valve sleeve, the two shaft end covers are symmetrically installed at the two ends of the valve body in the valve sleeve, the inner shaft cylinders are coaxially fixed in the shaft end covers, and the pilot valves are arranged on the pilot valves. The two inner shaft cylinders are internally connected with pilot valves in a sliding manner; a main oil duct is axially arranged in the valve body; a valve rod moving back and forth in the axial direction of the valve body is connected into the main oil duct in a sliding mode, three pressure adjusting pistons are distributed on the valve rod, and the pressure adjusting pistons make contact with the inner wall of the valve body in a sealed mode. An air seal unit is mounted on one of the shaft end covers outside the valve sleeve, and is connected with the pressure regulating pistons; the air seal unit can adjust the sealing contact strength of the pressure adjusting piston and the valve body according to the oil pressure environment, and it is ensured that the optimal sealing effect can be kept under various pressure conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic reversing valves, in particular to a three-position high-pressure hydraulic directional switching valve. Background Art

[0002] The three-position high-pressure hydraulic directional switching valve is a key component in the hydraulic system, used to control the direction and pressure of the liquid flow. Its main function is to switch the fluid path by changing the position of the valve core under different working conditions, so as to meet the needs of different working conditions; and with the development of modern industry, the performance requirements of the hydraulic system are getting higher and higher, especially in terms of stability, reliability and response speed under high pressure, high flow and complex working conditions, requiring the valve core to be able to reach the specified position quickly and accurately, and have high sealing performance, but the friction between the piston and the cylinder of the ordinary three-position switching valve during oil circuit switching may cause slow action, especially in low temperature or poor lubrication conditions, and the sealing ring on the piston is prone to wear after long-term use, resulting in internal leakage, which seriously affects its service life.

[0003] Therefore, it is necessary to provide a three-position high-pressure hydraulic directional switching valve to solve the problems raised in the above background technology. Summary of the invention

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a three-position high-pressure hydraulic directional switching valve, comprising: a valve sleeve, a valve body, a shaft end cover, an inner shaft cylinder, a pilot valve and an electromagnetic coil, the center of the valve body is fixed in the valve sleeve, two shaft end covers are symmetrically installed at both ends of the valve body in the valve sleeve, an inner shaft cylinder is coaxially fixed in each of the shaft end covers, the two inner shaft cylinders are slidably connected to the pilot valve, and the electromagnetic coil is installed on the side of the inner shaft cylinder end away from the valve body; A main oil passage is axially arranged in the valve body, a valve stem that moves back and forth along the axial direction of the valve body is slidably connected in the main oil passage, each of the pilot valves is connected to a guide shaft, and the other ends of the two guide shafts are connected to the valve stem; three pressure regulating pistons are distributed on the valve stem, and each of the pressure regulating pistons is in sealing contact with the inner wall of the valve body; An air sealing unit is installed on one of the shaft end covers outside the valve sleeve, and the air sealing unit is connected to each of the pressure regulating pistons; Two annular grooves are provided on the side wall of the pressure regulating piston, an inner lining edge is fixed in each of the annular grooves, a rubber ring is provided on the outer periphery of the inner lining edge in the two annular grooves, shaft heads are coaxially and detachably installed on both sides of the interior of the pressure regulating piston, and a plurality of circumferentially arranged guide support rods are distributed on one side of each shaft head in the pressure regulating piston.

[0005] Preferably, a main oil passage is axially arranged in the valve body, an oil hole 1 and an oil hole 2 are arranged above the main oil passage, and an oil hole 3, an oil hole 4 and an oil hole 5 are arranged in sequence below the main oil passage; a liquid cavity is sealed outside the oil hole 1 and the oil hole 2; Each of the guide support rods is radially slidably connected in the pressure regulating piston, and one end thereof abuts against the edge of the inner liner; The gas sealing unit supports the rubber rings in each pressure regulating piston by means of the guide support rod.

[0006] Preferably, pressure relief plates are symmetrically arranged at both ends of the pressure regulating piston, and the pressure relief plates are slidably connected in the shaft head, so that a pressure relief space is formed between the pressure relief plates on two adjacent pressure regulating pistons; An inner spring is connected between the pressure relief plate and the shaft head.

[0007] Preferably, a fixed disk is rotatably connected inside the pressure regulating piston, and a plurality of guide grooves corresponding to the guide support rods are opened on the fixed disk, and each guide groove is inclined, and a fixed shaft is vertically fixed on the guide support rod, and the fixed shaft is slidably connected in the guide groove; A coupling block is fixed on the guide support rod, two connecting rods are fixed on the coupling block in parallel, and guard plates are fixed on the ends of the connecting rods, and the outer wall of the guard plate is in contact with the inner lining.

[0008] Preferably, the air sealing unit comprises: An air sealing cylinder, the interior of which is sealingly and slidably connected with a valve plug, and an air sealing hole is provided outside the air sealing cylinder; The center rod is set as a two-stage telescopic structure, the rotation of the center rod is connected in the gas sealing cylinder, and the telescopic end of the center rod is coaxially connected in the guide shaft and extends into the valve stem; the fixed disk in each pressure regulating piston is fixed to the center rod; A guide sleeve is fixed between the valve plug and the center rod. A slide groove is provided on the side wall of the guide sleeve. An axle pin is fixed on the center rod. The axle pin is slidably connected to the slide groove.

[0009] Preferably, the unfolded surface of the slide groove is a diagonal structure, so that when the valve plug slides axially along the air sealing cylinder under the push of air pressure, the sliding connection between the slide groove and the shaft pin drives the center rod to perform circumferential deflection, thereby controlling the radial displacement of each guide support rod.

[0010] Preferably, a pulse tube and a flow stabilizing tube are connected in parallel outside the air sealing hole.

[0011] Preferably, a plunger rod is slidably sealed in the coupling block, and one end of the plunger rod is fixed to the guard plate; A sealing cavity is provided in the shaft head, and the pressure relief plate is slidingly and sealingly connected to the sealing cavity; a plurality of through holes are provided on the inner circumference of the shaft head, each of the through holes is connected to the sealing cavity, and a guide cavity is provided in the pressure regulating piston, and the guide cavity is arranged as an annular structure, and a connecting hole is provided on the side wall of each coupling block.

[0012] Preferably, the connecting hole on the coupling block is always sealed and docked with the guide cavity during the radial sliding of the guide support rod.

[0013] Preferably, when the pressure relief plate is axially displaced as the oil pressure in the valve body changes, the plunger rod in each coupling block dynamically adjusts the contact sealing performance between the rubber ring and the inner wall of the valve body.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The pressure regulating piston mainly used in the present invention is slidably mounted with a pressure relief plate, and a pressure relief space is formed between adjacent pressure regulating pistons, so that pressure fluctuations can be mitigated in a high-pressure, high-flow oil circuit environment, thereby improving the system flow control accuracy; and the guide support rod also provided in the pressure regulating piston can perform pressure expansion support adjustment on the rubber ring on the pressure regulating piston, so as to reduce the friction between the rubber ring and the inner wall of the valve body during the switching of the valve body oil circuit, further improve the system response speed, and extend its service life; at the same time, the air seal unit also used can adjust the sealing contact strength between the pressure regulating piston and the valve body according to the oil pressure environment, ensuring that the best sealing effect can be maintained under various pressure conditions. This not only improves the sealing reliability of the system, but also effectively prevents leakage, protects the rubber ring from damage, and ensures that it maintains good sealing performance for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the three-dimensional structure of the pressure regulating piston in the present invention; Figure 3 It is a schematic diagram of the inner cross-section plane of the pressure regulating piston in the present invention; Figure 4 It is a schematic diagram of the internal three-dimensional structure of the pressure regulating piston in the present invention; Figure 5 It is a structural schematic diagram of the guide support rod and the coupling block in the present invention; Figure 6 It is a schematic structural diagram of the gas sealing unit in the present invention; Figure 7 for Figure 3 A schematic diagram of the structure enlargement in the middle; In the figure: 1. valve body; 11. valve sleeve; 12. shaft end cover; 13. inner shaft cylinder; 14. electromagnetic coil; 15. oil hole one; 16. oil hole two; 17. oil hole three; 18. oil hole four; 19. oil hole five; 2. pilot valve; 21. guide shaft; 3. valve stem; 4. pressure regulating piston; 41. lining edge; 42. rubber ring; 43. shaft head; 44. guide support rod; 45. pressure relief plate; 46. inner spring; 47. sealing chamber; 48. through hole; 49. diversion chamber; 5. gas seal unit; 51. gas seal cylinder; 52. valve plug; 53. gas seal hole; 54. center rod; 55. guide sleeve; 56. shaft nail; 6. fixed plate; 61. fixed shaft; 62. coupling block; 63. connecting rod; 64. guard plate; 65. plunger rod. DETAILED DESCRIPTION

[0016] See also Figure 1-Figure 7 In an embodiment of the present invention, a three-position high-pressure hydraulic directional switching valve comprises: a valve sleeve 11, a valve body 1, a shaft end cover 12, an inner shaft cylinder 13, a pilot valve 2 and an electromagnetic coil 14. The center of the valve body 1 is fixed in the valve sleeve 11. Two shaft end covers 12 are symmetrically installed at both ends of the valve body 1 in the valve sleeve 11. An inner shaft cylinder 13 is coaxially fixed in each of the shaft end covers 12. The pilot valve 2 is slidably connected in the two inner shaft cylinders 13. The electromagnetic coil 14 is installed on the side of the end of the inner shaft cylinder 13 away from the valve body 1. A main oil passage is axially arranged in the valve body 1, and an oil hole 15 and an oil hole 2 16 are arranged above the main oil passage, and an oil hole 3 17, an oil hole 4 18 and an oil hole 5 19 are arranged in sequence below the main oil passage; a liquid cavity is sealed outside the oil hole 15 and the oil hole 2 16; A valve stem 3 that moves back and forth axially along the valve body 1 is slidably connected in the main oil passage, and each of the pilot valves 2 is connected to a guide shaft 21, and the other ends of the two guide shafts 21 are connected to the valve stem 3; three pressure regulating pistons 4 are distributed on the valve stem 3, and each of the pressure regulating pistons 4 is in sealing contact with the inner wall of the valve body 1; wherein, the electromagnetic coil 14 can accurately control the axial sliding of the pilot valve 2 in the inner shaft cylinder 13 when powered on, and achieves accurate control of the piston movement by adjusting the magnitude and direction of the current; and in the initial state, the oil hole four 18 is connected to the oil hole two 16 for liquid inlet, and the oil hole one 15 is connected to the oil hole three 17 for liquid discharge; and when the electromagnetic coil 14 is energized, the pilot valve 2 is axially displaced, and the pressure regulating piston 4 on the valve stem 3 is synchronously slid and adjusted, so that the oil hole four 18 is connected to the oil hole one 15 for liquid inlet, and the oil hole two 16 is connected to the oil hole five 19 for liquid discharge, thereby completing the oil circuit switching (the above all belong to the prior art and will not be described in detail); An air seal unit 5 is installed on one of the shaft end covers 12 outside the valve sleeve 11. The air seal unit 5 is connected to each of the pressure regulating pistons 4. The air seal unit 5 is used to adjust the contact sealing performance between the pressure regulating piston 4 and the inner wall of the valve body 1, so as to ensure smooth contact between the pressure regulating piston 4 and the valve body 1 during oil circuit switching, and maintain the best sealing state of the pressure regulating piston 4 according to the oil pressure environment after the oil circuit switching is completed; The side wall of the pressure regulating piston 4 is provided with two annular grooves, each of which is fixed with an inner lining edge 41, and a rubber ring 42 is sleeved on the outer periphery of the inner lining edge 41 in the two annular grooves, and shaft heads 43 are coaxially and detachably installed on both sides of the inner part of the pressure regulating piston 4, and a plurality of circumferentially arranged guide support rods 44 are distributed on one side of each shaft head 43 in the pressure regulating piston 4, and each of the guide support rods 44 is radially slidably connected in the pressure regulating piston 4, and one end thereof abuts against the inner lining edge 41; The gas sealing unit 5 supports the rubber ring 42 in each pressure regulating piston 4 by means of the guide support rod 44, so as to reduce the contact friction between the rubber ring 42 and the inner wall of the valve body 1 when the oil circuit is switched, reduce wear, and improve the later sealing performance and service life; and after the oil circuit is switched, the contact pressure between the rubber ring 42 and the inner wall of the valve body 1 can be increased by the gas sealing unit 5, thereby maintaining the sealing performance of the pressure regulating piston 4.

[0017] In this embodiment, pressure relief plates 45 are symmetrically arranged at both ends of the pressure regulating piston 4, and the pressure relief plates 45 are slidably connected to the shaft head 43, so that a pressure relief space is formed between the pressure relief plates 45 on two adjacent pressure regulating pistons 4; thereby, pressure fluctuations can be mitigated in a high-pressure, high-flow oil circuit environment; An inner spring 46 is connected between the pressure relief plate 45 and the shaft head 43 .

[0018] As a preferred embodiment, a fixed plate 6 is rotatably connected inside the pressure regulating piston 4, and a plurality of guide grooves corresponding to the guide support rods 44 are opened on the fixed plate 6, and each of the guide grooves is inclined. A fixed shaft 61 is vertically fixed on the guide support rods 44, and the fixed shaft 61 is slidably connected in the guide groove; A coupling block 62 is fixed to the guide support rod 44, and two connecting rods 63 are fixed in parallel to the coupling block 62. Guard plates 64 are fixed to the ends of the connecting rods 63, and the outer wall of the guard plate 64 is in contact with the inner lining edge 41. In other words, each guide support rod 44 forms a radial support for the inner lining edge 41 through the guard plate 64, thereby avoiding direct contact with the rubber ring 42, and the inner lining edge 41 provides a corresponding supporting effect on the rubber ring 42, ensuring that the rubber ring 42 is evenly stressed as a whole, thereby ensuring its sealing effect.

[0019] In this embodiment, the gas sealing unit 5 includes: An air sealing cylinder 51, the interior of which is sealingly and slidably connected with a valve plug 52, and an air sealing hole 53 is formed outside the air sealing cylinder 51; The center rod 54 is configured as a two-stage telescopic structure. The rotation of the center rod 54 is connected to the gas sealing cylinder 51, and the telescopic end of the center rod 54 is coaxially connected to the guide shaft 21 and extends into the valve stem 3. The fixed disk 6 in each of the pressure regulating pistons 4 is fixed to the center rod 54. The guide sleeve 55 is fixed between the valve plug 52 and the center rod 54 . A slide groove is provided on the side wall of the guide sleeve 55 . A shaft pin 56 is fixed on the center rod 54 . The shaft pin 56 is slidably connected to the slide groove.

[0020] In this embodiment, the unfolded surface of the slide groove is a diagonal structure, so that when the valve plug 52 slides axially along the air sealing cylinder 51 under the push of air pressure, the sliding connection between the slide groove and the axis pin 56 drives the center rod 54 to perform circumferential deflection, thereby controlling the radial displacement of each guide support rod 44.

[0021] In this embodiment, a pulse tube and a flow stabilizing tube (neither of which is shown in the figure) are connected in parallel to the outside of the gas sealing hole 53. The pulse tube can provide a pulse airflow, while the flow stabilizing tube can provide a constant-pressure airflow. Therefore, in the specific control and regulation, the flow stabilizing tube is preferably used to control the sliding adjustment of the valve plug 52 in the gas sealing cylinder 51, so that the rubber ring 42 on each pressure regulating piston 4 can provide a contact effect adapted to the inner wall of the valve body according to the oil pressure regulation in the oil circuit, thereby ensuring the sealing performance; and when the oil circuit of the valve body remains unchanged, the pulse tube works and drives the valve plug 52 to perform a certain amplitude of axial reciprocating displacement, so that the rubber ring 42 on each pressure regulating piston 4 can achieve a continuous dynamic change in the contact pressure with the valve body, which, on the one hand, avoids excessive extrusion of the rubber ring under high pressure or extreme conditions, thereby reducing its wear; on the other hand, the rubber ring can dynamically adjust the contact pressure according to actual needs, thereby reducing the hysteresis caused by friction and elastic deformation, and making the subsequent system oil circuit switching action smoother.

[0022] As a preferred embodiment, a plunger rod 65 is slidably sealed in the coupling block 62, and one end of the plunger rod 65 is fixed to the guard plate 64; A sealing chamber 47 is provided in the shaft head 43, and the pressure relief plate 45 is slidingly and sealingly connected to the sealing chamber 47; a plurality of through holes 48 are provided on the inner circumference of the shaft head 43, and each of the through holes 48 is connected to the sealing chamber 47, and a guide chamber 49 is provided in the pressure regulating piston 4, and the guide chamber 49 is arranged in an annular structure, and a connecting hole is provided on the side wall of each of the coupling blocks 62.

[0023] In this embodiment, the connecting hole on the connecting block 62 slides radially with the guide support rod 44 and is always sealed and connected with the guide cavity 49.

[0024] In this embodiment, when the pressure relief plate 45 performs axial displacement as the oil pressure in the valve body 1 changes, the plunger rod 65 in each of the coupling blocks 62 dynamically adjusts the contact sealing between the rubber ring and the inner wall of the valve body 1. That is to say, when the oil flow in the valve body changes unstably, the pressure relief plate 45 on each pressure regulating piston 4 performs corresponding sliding displacement. At this time, it can perform air pressure sliding adjustment on the plunger rod 65 in the coupling block 62 through the through hole 48, so that each plunger rod 65 provides adaptive expansion and support changes to the rubber ring 42 outside the lining edge 41 through the guard plate 64 during the sliding displacement, thereby improving the sealing flexibility of each pressure regulating piston 4.

[0025] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A three-position high-pressure hydraulic directional switching valve, comprising: A valve sleeve (11), a valve body (1), an end cover (12), an inner shaft cylinder (13), a pilot valve (2) and an electromagnetic coil (14), characterized in that the center of the valve body (1) is fixed in the valve sleeve (11), two end covers (12) are symmetrically installed in the valve sleeve (11) at both ends of the valve body (1), an inner shaft cylinder (13) is coaxially fixed in each of the end covers (12), the two inner shaft cylinders (13) are slidably connected to the pilot valve (2), and the electromagnetic coil (14) is installed on the side of the end of the inner shaft cylinder (13) away from the valve body (1); A main oil passage is axially arranged in the valve body (1); a valve stem (3) is slidably connected in the main oil passage and moves back and forth along the axial direction of the valve body (1); each of the pilot valves (2) is connected to a guide shaft (21); the other ends of the two guide shafts (21) are connected to the valve stem (3); three pressure regulating pistons (4) are distributed on the valve stem (3); each of the pressure regulating pistons (4) is in sealing contact with the inner wall of the valve body (1); An air sealing unit (5) is installed on one of the shaft end covers (12) outside the valve sleeve (11), and the air sealing unit (5) is connected to each of the pressure regulating pistons (4); Two annular grooves are provided on the side wall of the pressure regulating piston (4), and an inner lining edge (41) is fixed in each of the annular grooves. A rubber ring (42) is sleeved on the outer periphery of the inner lining edge (41) in the two annular grooves. Shaft heads (43) are coaxially and detachably mounted on both sides of the interior of the pressure regulating piston (4). A plurality of guide support rods (44) are distributed circumferentially on one side of each shaft head (43) in the pressure regulating piston (4).

2. A three-position high-pressure hydraulic directional switching valve according to claim 1, characterized in that: A main oil passage is axially arranged in the valve body (1), an oil hole 1 (15) and an oil hole 2 (16) are arranged above the main oil passage, and an oil hole 3 (17), an oil hole 4 (18) and an oil hole 5 (19) are arranged in sequence below the main oil passage; a liquid cavity is sealed outside the oil hole 1 (15) and the oil hole 2 (16); Each of the guide support rods (44) is radially slidably connected in the pressure regulating piston (4), and one end thereof abuts against the inner lining edge (41); The gas sealing unit (5) supports the rubber ring (42) in each pressure regulating piston (4) through the guide support rod (44) for pressure expansion.

3. A three-position high-pressure hydraulic directional switching valve according to claim 1, characterized in that: Pressure relief plates (45) are symmetrically arranged at both ends of the pressure regulating piston (4), and the pressure relief plates (45) are slidably connected in the shaft head (43), so that a pressure relief space is formed between the pressure relief plates (45) on two adjacent pressure regulating pistons (4); An inner spring (46) is connected between the pressure relief plate (45) and the shaft head (43).

4. A three-position high-pressure hydraulic directional switching valve according to claim 3, characterized in that: A fixed disk (6) is rotatably connected inside the pressure regulating piston (4), and a plurality of guide grooves corresponding to the guide support rods (44) are formed on the fixed disk (6), each of the guide grooves is arranged obliquely, and a fixed shaft (61) is vertically fixed on each of the guide support rods (44), and the fixed shaft (61) is slidably connected in the guide groove; A coupling block (62) is fixed on the guide support rod (44), two connecting rods (63) are fixed in parallel on the coupling block (62), and guard plates (64) are fixed at the ends of the connecting rods (63), and the outer wall of the guard plate (64) is in contact with the inner lining edge (41).

5. A three-position high-pressure hydraulic directional switching valve according to claim 4, characterized in that: The gas sealing unit (5) comprises: An air sealing cylinder (51) having a valve plug (52) in sealing and sliding connection therewith inside, and an air sealing hole (53) outside the air sealing cylinder (51); The center rod (54) is configured as a two-stage telescopic structure, the center rod (54) is rotatably connected in the gas sealing cylinder (51), and the telescopic end of the center rod (54) is coaxially connected to the guide shaft (21) and extends into the valve stem (3); the fixed disk (6) in each of the pressure regulating pistons (4) is fixed to the center rod (54); A guide sleeve (55) is fixed between the valve plug (52) and the center rod (54); a slide groove is provided on the side wall of the guide sleeve (55); and an axle pin (56) is fixed on the center rod (54); the axle pin (56) is slidably connected to the slide groove.

6. A three-position high-pressure hydraulic directional switching valve according to claim 5, characterized in that: The unfolded surface of the slide groove is an oblique line structure, so that when the valve plug (52) slides axially along the gas sealing cylinder (51) under the push of air pressure, the sliding connection between the slide groove and the shaft pin (56) drives the center rod (54) to perform circumferential deflection, thereby controlling the radial displacement of each guide support rod (44).

7. A three-position high-pressure hydraulic directional switching valve according to claim 6, characterized in that: A pulse tube and a flow stabilizing tube are connected in parallel outside the gas sealing hole (53).

8. The three-position high-pressure hydraulic directional switching valve according to claim 4, characterized in that: A plunger rod (65) is slidably and sealably connected inside the coupling block (62), and one end of the plunger rod (65) is fixed to the guard plate (64); A sealing chamber (47) is provided in the shaft head (43), and the pressure relief plate (45) is slidably sealedly connected to the sealing chamber (47); a plurality of through holes (48) are provided on the inner circumference of the shaft head (43), and each of the through holes (48) is connected to the sealing chamber (47); a guide chamber (49) is provided in the pressure regulating piston (4), and the guide chamber (49) is configured as an annular structure; and a connecting hole is provided on the side wall of each of the coupling blocks (62).

9. A three-position high-pressure hydraulic directional switching valve according to claim 8, characterized in that: The connecting hole on the coupling block (62) is always sealed and butted against the guide cavity (49) during radial sliding along with the guide support rod (44).

10. A three-position high-pressure hydraulic directional switching valve according to claim 9, characterized in that: When the pressure relief plate (45) is axially displaced as the oil pressure in the valve body (1) changes, the plunger rod (65) in each of the coupling blocks (62) dynamically adjusts the contact sealing performance between the rubber ring (42) and the inner wall of the valve body (1).

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