A three-position high-pressure hydraulic direction change-over valve

Abstract

The present invention discloses a three-position high-pressure hydraulic direction switching valve, belonging to the technical field of hydraulic reversing valves, which comprises: a valve sleeve, a valve body, an end cover, an inner shaft cylinder, a pilot valve and an electromagnetic coil. The center of the valve body is fixed within the valve sleeve. At both ends of the valve body within the valve sleeve, two end covers are symmetrically installed. An inner shaft cylinder is coaxially fixed within each end cover, and a pilot valve is slidably connected within each of the two inner shaft cylinders. A main oil passage is axially arranged within the valve body. A valve rod that moves back and forth along the axial direction of the valve body is slidably connected within the main oil passage. Three pressure regulating pistons are distributed on the valve rod, and each pressure regulating piston is in sealing contact with the inner wall of the valve body. An air sealing unit is installed on the valve sleeve outside one of the end covers, and the air sealing unit is connected to each of the pressure regulating pistons. In the present invention, the air sealing unit can adjust the sealing contact strength between the pressure regulating piston and the valve body according to the oil pressure environment, ensuring the best sealing effect under various pressure conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic directional control valves, and specifically relates to a three-position high-pressure hydraulic direction switching valve. Background Art

[0002] The three-position high-pressure hydraulic direction switching valve is a key component in a hydraulic system, used to control the direction and pressure of liquid flow. Its main function is to switch the fluid path by changing the position of the spool under different working conditions to meet the requirements of different working conditions; with the development of modern industry, the performance requirements for hydraulic systems are getting higher and higher, especially in terms of stability, reliability, and response speed under high pressure, high flow rate, and complex working conditions. It is required that the spool can reach the specified position quickly and accurately and have high sealing performance. However, the friction between the piston and the cylinder barrel during the oil path switching of ordinary three-position switching valves may cause slow movement, especially in low-temperature or poor lubrication conditions. At the same time, the sealing rings on the piston are prone to wear after long-term use, resulting in internal leakage and seriously affecting its service life.

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

[0004] To achieve the above object, the present invention provides the following technical solution: A three-position high-pressure hydraulic direction switching valve, which includes: a valve sleeve, a valve body, an 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 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 end cover. The pilot valves are slidably connected in the two inner shaft cylinders. The electromagnetic coil is installed on the side of the inner shaft cylinder away from the valve body;

[0005] A main oil passage is axially arranged in the valve body. A valve rod that moves back and forth along the axial direction of the valve body is slidably connected in the main oil passage. A guide shaft is connected to each pilot valve. The other ends of the two guide shafts are both connected to the valve rod; Three pressure regulating pistons are distributed on the valve rod. Each pressure regulating piston is in sealing contact with the inner wall of the valve body;

[0006] An air sealing unit is installed on the valve sleeve outside one of the end covers. The air sealing unit is connected to each pressure regulating piston;

[0007] Two annular grooves are formed on the side wall of the pressure regulating piston. A lining edge is fixed in each annular groove. A rubber ring is sleeved outside the lining edge in each annular groove. Axial heads are detachably installed on both sides of the pressure regulating piston coaxially. A plurality of circumferentially arranged guide support rods are distributed on one side of each axial head in the pressure regulating piston.

[0008] Preferably, a main oil passage is axially arranged in the valve body. Above the main oil passage, there are a first oil hole and a second oil hole, and below the main oil passage, there are a third oil hole, a fourth oil hole, and a fifth oil hole arranged in sequence. Liquid chambers are hermetically arranged outside both the first oil hole and the second oil hole.

[0009] Each of the guide support rods is radially slidably connected in the pressure regulating piston, and one end thereof abuts against the inner lining edge.

[0010] The air sealing unit expands and supports the rubber rings in each pressure regulating piston through the guide support rods.

[0011] Preferably, buffer plates are symmetrically arranged at both ends of the pressure regulating piston. The buffer plates are slidably connected in the shaft head, so that a buffer space is formed between the buffer plates on adjacent pressure regulating pistons.

[0012] An inner spring is connected between the buffer plate and the shaft head.

[0013] Preferably, a fixed disk is rotatably connected in the pressure regulating piston. A plurality of guide grooves corresponding to the guide support rods are formed on the fixed disk. Each of the guide grooves is inclined. Fixed shafts are perpendicularly fixed on the guide support rods, and the fixed shafts are slidably connected in the guide grooves.

[0014] A coupling block is fixed on the guide support rod. Two connecting rods are fixedly arranged in parallel on the coupling block. Guards are fixedly arranged at the ends of the connecting rods, and the outer walls of the guards are in contact with the inner lining edge.

[0015] Preferably, the air sealing unit includes:

[0016] An air sealing cylinder, in which a valve plug is hermetically and slidably connected. There is an air sealing hole outside the air sealing cylinder.

[0017] A center rod, which is arranged as a two-stage telescopic structure. The center rod is rotatably connected in the air sealing cylinder, and the telescopic end of the center rod is coaxially inserted into the guide shaft and extends into the valve rod. The fixed disks in each pressure regulating piston are fixed to the center rod.

[0018] A guide sleeve is fixed between the valve plug and the center rod. A sliding groove is formed on the side wall of the guide sleeve, and a shaft nail is fixed on the center rod. The shaft nail is slidably connected with the sliding groove.

[0019] Preferably, the unfolded surface of the sliding groove is a diagonal line structure, so that when the valve plug slides axially along the air sealing cylinder under the action of air pressure, the center rod is driven to perform circumferential deflection through the sliding connection between the sliding groove and the shaft nail, thereby controlling the radial displacement of each guide support rod.

[0020] Preferably, a pulse tube and a steady flow tube are connected in parallel outside the air sealing hole.

[0021] Preferably, a plunger rod is slidably and sealingly connected inside the coupling block, and one end of the plunger rod is fixed to the guard plate;

[0022] A sealing cavity is provided inside the shaft head, and the pressure relief plate is slidably and sealingly connected to the sealing cavity; a plurality of through holes are formed in the inner circumference of the shaft head, and each of the through holes communicates with the sealing cavity, and a diversion cavity is provided inside the pressure regulating piston, and the diversion cavity is arranged in an annular structure, and connecting holes are formed in the side walls of each of the coupling blocks.

[0023] Preferably, the connecting holes on the coupling block are always in sealing butt joint with the diversion cavity during the radial sliding of the guide support rod.

[0024] Preferably, when the pressure relief plate axially displaces with the change of the oil pressure in the valve body, the plunger rods in each of the coupling blocks dynamically adjust the contact sealing performance between the rubber ring and the inner wall of the valve body.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] In the present invention, a pressure relief plate is slidably installed on the pressure regulating piston mainly, and a pressure relief space is formed between adjacent pressure regulating pistons, so as to be able to slow down the pressure fluctuation in the oil circuit environment of high pressure and high flow rate and improve the system flow control accuracy; and a guide support rod provided in the pressure regulating piston can also perform pressure expansion support adjustment on the rubber ring on the pressure regulating piston, so as to reduce the friction force between the rubber ring and the inner wall of the valve body during the switching of the oil circuit in the valve body, further improve the system response speed and extend its service life; at the same time, an air sealing unit is also adopted, which can adjust the sealing contact strength between the pressure regulating piston and the valve body according to the oil pressure environment, ensuring the best sealing effect under various pressure conditions. This not only improves the sealing reliability of the system, but also can effectively prevent leakage, protect the rubber ring from damage, and ensure its long-term good sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 is a three-dimensional structure schematic diagram of the pressure regulating piston in the present invention;

[0029] Figure 3 is a schematic diagram of the internal sectional plane of the pressure regulating piston in the present invention;

[0030] Figure 4 is a three-dimensional structure schematic diagram of the inside of the pressure regulating piston in the present invention;

[0031] Figure 5 is a schematic diagram of the structure of the guide support rod and the coupling block in the present invention;

[0032] Figure 6Structural schematic diagram of the air seal unit in the present invention;

[0033] Figure 7 is Figure 3 enlarged schematic diagram of the structure at position A in

[0034] In the figure: 1. Valve body; 11. Valve sleeve; 12. Shaft end cover; 13. Inner shaft cylinder; 14. Electromagnetic coil; 15. Oil hole 1; 16. Oil hole 2; 17. Oil hole 3; 18. Oil hole 4; 19. Oil hole 5; 2. Pilot valve; 21. Guide shaft; 3. Valve rod; 4. Pressure regulating piston; 41. Inner lining edge; 42. Rubber ring; 43. Shaft head; 44. Guide support rod; 45. Buffer plate; 46. Inner spring; 47. Sealing cavity; 48. Through hole; 49. Flow guiding cavity; 5. Air seal unit; 51. Air seal cylinder; 52. Valve plug; 53. Air seal hole; 54. Central rod; 55. Guide sleeve; 56. Axle nail; 6. Fixed disk; 61. Fixed shaft; 62. Coupling block; 63. Connecting rod; 64. Guard plate; 65. Plunger rod. Specific embodiments

[0035] Please refer to Figures 1 - 7 , in the embodiment of the present invention, a three-position high-pressure hydraulic direction switching valve includes: 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 inside the valve sleeve 11. Two shaft end covers 12 are symmetrically installed at both ends of the valve body 1 inside the valve sleeve 11. An inner shaft cylinder 13 is coaxially fixed inside each shaft end cover 12. The pilot valve 2 is slidably connected inside both inner shaft cylinders 13. The electromagnetic coil 14 is installed on the side of the inner shaft cylinder 13 away from the valve body 1 at the end;

[0036] A main oil passage is axially arranged inside the valve body 1. An oil hole 15 and an oil hole 16 are provided above the main oil passage, and an oil hole 17, an oil hole 18, and an oil hole 19 are sequentially arranged below the main oil passage. Liquid cavities are hermetically arranged outside both the oil hole 15 and the oil hole 16;

[0037] A valve rod 3 that slides back and forth along the axial direction of the valve body 1 is slidably connected in the main oil passage. Guide shafts 21 are connected to each of the pilot valves 2, and the other ends of the two guide shafts 21 are both connected to the valve rod 3. Three pressure regulating pistons 4 are distributed on the valve rod 3, and each of the pressure regulating pistons 4 is in sealing contact with the inner wall of the valve body 1. Among them, the electromagnetic coil 14 can accurately control the axial sliding of the pilot valve 2 in the inner shaft cylinder 13 in the energized state, and by adjusting the magnitude and direction of the current, the accurate control of the piston movement can be achieved. In the initial state, the oil hole four 18 is connected to the oil hole two 16 to admit liquid, and the oil hole one 15 is connected to the oil hole three 17 to drain liquid. When the electromagnetic coil 14 is energized, the pilot valve 2 axially displaces, and the pressure regulating pistons 4 on the valve rod 3 synchronously slide and adjust, so that the oil hole four 18 is connected to the oil hole one 15 to admit liquid, and the oil hole two 16 is connected to the oil hole five 19 to drain liquid, thus completing the oil circuit switching (the above all belong to the prior art and will not be elaborated too much).

[0038] 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 tightness between the pressure regulating piston 4 and the inner wall of the valve body 1, so as to ensure the smooth contact between the pressure regulating piston 4 and the valve body 1 during the 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.

[0039] Two ring grooves are formed on the side wall of the pressure regulating piston 4. Inner linings 41 are fixed in each of the ring grooves. Rubber rings 42 are sleeved outside the inner linings 41 in the two ring grooves. Axial heads 43 are detachably installed coaxially on both sides inside the pressure regulating piston 4. A plurality of circumferentially arranged guide struts 44 are distributed on one side of each axial head 43 inside the pressure regulating piston 4. Each of the guide struts 44 is slidably connected radially inside the pressure regulating piston 4, and one end of it abuts against the inner lining 41.

[0040] The air seal unit 5 expands and supports the rubber rings 42 in each pressure regulating piston 4 through the guide struts 44, so as to reduce the contact friction between the rubber rings 42 and the inner wall of the valve body 1 during the oil circuit switching, reduce wear, improve the later tightness and service life. After the oil circuit switching is completed, the contact pressure between the rubber rings 42 and the inner wall of the valve body 1 can be increased through the air seal unit 5, so as to maintain the tightness of the pressure regulating piston 4.

[0041] In this embodiment, pressure relief plates 45 are symmetrically arranged at both ends of the pressure regulating piston 4. The pressure relief plates 45 are both slidably connected inside the axial heads 43, so that a pressure relief space is formed between the pressure relief plates 45 on two adjacent pressure regulating pistons. Thus, the pressure fluctuation can be slowed down in the oil circuit environment of high pressure and high flow rate.

[0042] An inner spring 46 is connected between the pressure relief plate 45 and the axial head 43.

[0043] As a preferred embodiment, a fixed disk 6 is rotatably connected inside the pressure regulating piston 4. A plurality of guide grooves corresponding to the guide support rods 44 are formed in the fixed disk 6. Each of the guide grooves is inclined. Fixed shafts 61 are perpendicularly fixed on each of the guide support rods 44. The fixed shafts 61 are slidably connected in the guide grooves.

[0044] A coupling block 62 is fixed on the guide support rod 44. Two connecting rods 63 are fixedly arranged in parallel on the coupling block 62. End parts of the connecting rods 63 are both fixed with guard plates 64. The outer walls of the guard plates 64 are in contact with the inner lining edge 41. That is to say, each guide support rod 44 radially supports the inner lining edge 41 through the guard plate 64, so as to avoid 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 whole rubber ring 42 is uniformly stressed, thereby ensuring its sealing effect.

[0045] In this embodiment, the air sealing unit 5 includes:

[0046] An air sealing cylinder 51, inside which a valve plug 52 is hermetically and slidably connected. There is an air sealing hole 53 outside the air sealing cylinder 51;

[0047] A center rod 54, which is arranged as a two-stage telescopic structure. The center rod 54 is rotatably connected inside the air sealing cylinder 51, and the telescopic end of the center rod 54 is coaxially inserted into the guide shaft 21 and extends into the valve rod 3. The fixed disks 6 inside each pressure regulating piston 4 are all fixed to the center rod 54;

[0048] A guide sleeve 55, which is fixed between the valve plug 52 and the center rod 54. A chute is formed in the side wall of the guide sleeve 55. A shaft nail 56 is fixed on the center rod 54. The shaft nail 56 is slidably connected with the chute.

[0049] In this embodiment, the unfolded surface of the chute is an inclined line structure. When the valve plug 52 axially slides in the air sealing cylinder 51 under the action of air pressure, the center rod 54 is driven to deflect circumferentially through the sliding connection between the chute and the shaft nail 56, so as to control the radial displacement of each guide support rod 44.

[0050] In this embodiment, a pulse tube and a flow stabilizing tube (not shown in the figure) are connected in parallel outside the air seal hole 53. The pulse tube can provide pulsed air flow, and the flow stabilizing tube can provide constant-pressure air flow. Therefore, in specific control and adjustment, the flow stabilizing tube is preferably used to control the sliding adjustment of the valve plug 52 in the air seal cylinder 51, so that the rubber rings 42 on each pressure regulating piston 4 can adjust to provide a contact effect suitable for the inner wall of the valve body according to the oil pressure in the oil circuit, ensuring the sealing performance; when the oil circuit of the valve body remains unchanged continuously, the pulse tube works and drives the valve plug 52 to perform axial reciprocating displacement within a certain range, so that the contact pressure between the rubber rings 42 on each pressure regulating piston 4 and the valve body can reach continuous dynamic change. On the one hand, it avoids excessive extrusion of the rubber rings under high pressure or extreme conditions, thereby reducing their wear. On the other hand, the rubber rings can dynamically adjust the contact pressure according to actual needs, reducing the hysteresis phenomenon caused by friction and elastic deformation, and making the subsequent oil circuit switching operation of the system more smooth.

[0051] As a preferred embodiment, a plunger rod 65 is slidably and sealingly connected inside the coupling block 62, and one end of the plunger rod 65 is fixed to the guard plate 64.

[0052] A sealing cavity 47 is provided inside the shaft head 43, and the buffer plate 45 is slidably and sealingly connected to the sealing cavity 47; a plurality of through holes 48 are formed in the inner circumference of the shaft head 43, and each of the through holes 48 communicates with the sealing cavity 47. A diversion cavity 49 is provided inside the pressure regulating piston 4, and the diversion cavity 49 is arranged in an annular structure. Connecting holes are formed in the side walls of each coupling block 62.

[0053] In this embodiment, during the radial sliding of the connecting holes on the coupling block 62 along the guide strut rod 44, they are always in sealed butt joint with the diversion cavity 49.

[0054] In this embodiment, when the buffer plate 45 performs axial displacement along with the change of the oil pressure in the valve body 1, the plunger rods 65 in each coupling block 62 dynamically adjust the contact sealing performance between the rubber ring and the inner wall of the valve body 1. That is to say, when the oil flow rate in the oil circuit of the valve body changes unstably, the buffer plates 45 on each pressure regulating piston 4 perform corresponding sliding displacements. At this time, it can perform pneumatic sliding adjustment on the plunger rods 65 in the coupling blocks 62 through the through holes 48, so that each plunger rod 65 provides adaptive expansion change for the rubber ring 42 outside the inner liner edge 41 through the guard plate 64 during the sliding displacement, improving the sealing flexibility of each pressure regulating piston 4.

[0055] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within 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), 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); 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 installed on both sides of the interior of the pressure regulating piston (4). 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); An air seal unit (5) is installed on one of the shaft end covers (12) outside the valve sleeve (11), 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 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); Pressure-relief plates (45) are symmetrically arranged at both ends of the pressure-regulating piston (4), and an inner spring (46) is connected between the pressure-relief plate (45) and the shaft head (43); 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); 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); 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 slidably and 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).

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).

3. A three-position high-pressure hydraulic directional switching valve according to claim 1, characterized in that: The pressure relief plates (45) are all 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).

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.

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) is provided with a valve plug (52) in a sealing and sliding manner inside the air sealing cylinder (51), and an air sealing hole (53) is provided 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); 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 axis pin (56) is fixed on the center rod (54), and the axis 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 air seal 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 1, characterized in that: The connecting hole on the coupling block (62) is always sealed and butted with the guide cavity (49) during radial sliding along with the guide support rod (44).

9. A three-position high-pressure hydraulic directional switching valve according to claim 8, 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).

Images