Rotary Joint for High-Speed Dry Hobbing Machine

Abstract

The present invention discloses a rotary joint for a high-speed dry cutting hobbing machine, which includes an oil cylinder barrel. A piston rod is coaxially arranged at the center of the oil cylinder barrel. A piston cover is provided at one end of the oil cylinder barrel. One end of the piston rod extends into the oil cylinder barrel, and the other end of the piston rod passes through the piston cover and extends into the shell. A cover is connected to the shell. A joint A and a joint B are respectively provided on one side of the shell, and a joint C is provided on the other side of the shell. A cavity is provided between the oil cylinder barrel and the piston rod, and a one-way valve assembly is arranged in the cavity. A connecting cover is provided at the other end of the oil cylinder barrel. The present invention solves the problem that the existing rotary joint is locked at high rotational speeds.

Description

Technical Field

[0001] The present invention belongs to the technical field of machine tool processing and relates to a rotary joint for a high-speed dry-cutting hobbing machine. Background Art

[0002] The hobbing machine is one of the most widely used machine tools in gear processing machine tools. Straight teeth, helical cylindrical gears can be cut on the hobbing machine, and worm wheels, sprocket wheels, etc. can also be processed. The hobbing machine is a gear processing machine tool that processes straight teeth, helical teeth, and double helical teeth cylindrical gears and worm wheels according to the generating method. When using a special hob, this machine tool can also process workpieces with various special tooth profiles such as splines and sprocket wheels. As a key component of the tool holder of a high-speed and high-efficiency dry-cutting hobbing machine, the driving structure for tightening and loosening the hob, the two-way oil cylinder and the double-channel rotary joint for providing hydraulic pressure are crucial. The existing rotary joint only meets the needs at low speeds and can no longer meet the use performance of the machine tool at high speeds. Due to the limitation of the internal structure, the copper sleeve heats up at high speeds, resulting in the phenomenon of the rotary joint being locked. Once locked, the tool, the workpiece, and the oil pipe will break, bringing great difficulties to production. Summary of the Invention

[0003] The purpose of the present invention is to provide a rotary joint for a high-speed dry-cutting hobbing machine, which solves the problem of the existing rotary joint being locked at high speeds (2000 revolutions per minute).

[0004] The technical solution adopted by the present invention is that the rotary joint for a high-speed dry-cutting hobbing machine includes an oil cylinder barrel. A piston rod is coaxially arranged at the center of the oil cylinder barrel. A piston cover is arranged at one end of the oil cylinder barrel. One end of the piston rod extends into the oil cylinder barrel, and the other end of the piston rod passes through the piston cover and extends into the shell. A cover is connected to the shell. A joint A and a joint B are respectively arranged on one side of the shell, and a joint C is arranged on the other side of the shell. A cavity is arranged between the oil cylinder barrel and the piston rod, and a one-way valve assembly is arranged in this cavity. A connection cover is arranged at the other end of the oil cylinder barrel.

[0005] The characteristics of the present invention also lie in that:

[0006] The opposite sides of the shell are respectively assembled on the piston rod through a deep groove ball bearing A and a deep groove ball bearing B.

[0007] The piston rod is in a free state in the front oil cylinder barrel. An STU retaining ring B, an O-ring D, and an STU retaining ring C are sequentially arranged at the contact position between the piston rod and the inner wall of the oil cylinder barrel. The piston rod and the oil cylinder barrel are connected by hexagon socket head cap screws. A sleeve is coaxially arranged on the hexagon socket head cap screws. Two oil guide grooves are arranged on the piston rod, and an oil plug B and an oil plug C are respectively arranged on the two oil guide grooves.

[0008] A sealed oil cavity is formed between the piston cover and the oil cylinder barrel. The sealing ring C, the STU retaining ring A, and the O-ring C arranged at the piston cover are combined to seal the sealed oil cavity.

[0009] The one-way valve assembly is located in the sealed oil chamber. The one-way valve assembly includes a spring. One end of the spring is sleeved on the guiding screw, and the guiding screw is fastened to the inner wall of the cylinder barrel by threads. The other end of the spring is located within the push cover, and the push cover is connected to the piston rod by threads. The steel ball is located within the inner cavity of the push cover under the action of the spring, forming a one-way valve.

[0010] The beneficial effects of the present invention are as follows. Compared with the original rotary joint, the present invention features convenient installation, low failure rate, long service life, and no hydraulic oil leakage or seepage. Moreover, it significantly improves the tool change rhythm and the overall machine processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic structural diagram of the rotary joint of the present invention for a high-speed dry-cutting hobbing machine.

[0012] In the figure, 1. connecting cover, 2. lock washer, 3. hexagon socket head cap screw for oil, 4. steel ball, 5. cylinder barrel, 6. oil plug A, 7. top block, 8. piston cover, 9. sealing ring C, 10. sealing ring A, 11. joint A, 12. joint B, 13. O-ring A, 14. cover, 15. deep groove ball bearing A, 16. shaft snap ring, 17. piston rod, 18. sealing ring B, 19. gasket, 20. housing, 21. joint C, 22. deep groove ball bearing B, 23. hole snap ring, 24. STU snap ring A, 25. O-ring B, 26. O-ring C, 27. STU snap ring B, 28. O-ring D, 29. STU snap ring C, 30. hexagon screw, 31. sleeve, 32. oil plug B, 33. O-ring E, 34. oil plug C, 35. push cover, 36. spring, 37. guiding screw, 38. hexagon socket head cap screw. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] The present invention will be described in detail below in conjunction with the drawings and the specific embodiments.

[0014] The rotary joint of the present invention for a high-speed dry-cutting hobbing machine, as Figure 1 shown, includes a piston rod, an oil cylinder housing, a sealing ring, a spring, and a snap ring. Among them, the piston rod is driven by a two-way oil cylinder at the tail end to realize the tightening and loosening of the hob.

[0015] The rotary joint of the present invention is used for a high-speed dry-cut hobbing machine, including an oil cylinder barrel 5. Connecting covers 1 and piston covers 8 are respectively provided at opposite ends of the oil cylinder barrel 5. A piston rod 17 is coaxially provided at the center of the oil cylinder barrel 5. One end of the piston rod 17 passes through the piston cover and enters the oil cylinder barrel 5, and the other end of the piston rod 17 penetrates into a housing 20; the connecting cover 1 is connected to the oil cylinder barrel 5 by an internal hexagon screw 38. An O-ring seal E33 is provided at the contact between the oil cylinder barrel 5 and the piston rod 17. A seal ring C9 and an O-ring seal B25 are successively provided at the connection between the piston rod 17 and the piston cover 8;

[0016] The housing 20 of the tail-end rotary joint is assembled on the piston rod 17 as a whole through deep groove ball bearings A15 and deep groove ball bearings B22 on both sides. In order to prevent leakage of hydraulic oil, seal rings A10, seal rings B18 and O-ring seals A13 are installed on both sides of the rotary joint. A cover 14 is fastened to the housing 20 by internal hexagon screws to form an oil return cavity, so that the hydraulic oil returns to the machine tool hydraulic station. A hole retaining ring 23 is provided at one end of the housing 20 away from the cover 14.

[0017] Among them, a gasket 19 is restricted in its axial position by a shaft retaining ring 16. The piston rod 17 is in a free state inside the front-end oil cylinder barrel 5. STU retaining rings B27, O-ring seals D28 and STU retaining rings C29 are successively provided at the contact between the piston rod 17 and the inner wall of the oil cylinder barrel 5. The piston rod 17 and the oil cylinder barrel 5 are connected by a hexagon screw 30. A sleeve 31 is coaxially provided on the hexagon screw 30. Two oil guide grooves are provided on the piston rod 17, and an oil plug B32 and an oil plug C34 are respectively provided on the two oil guide grooves.

[0018] The connecting cover 1 is connected to the hob spindle and is fixedly connected to the oil cylinder barrel 5 by an internal hexagon screw. The piston cover 8 and the oil cylinder barrel 5 form a sealed oil cavity by an internal hexagon screw. Among them, the seal ring C9, STU retaining ring A24 and O-ring seal C26 on the right side of the piston cover 8 are combined for sealing. The O-ring seal C26 mainly prevents leakage of hydraulic oil in the oil cylinder barrel 5 and entry of external impurities.

[0019] An oil plug A6 is further provided inside the cylinder barrel of the oil cylinder barrel 5. In addition, an internal hexagon oil plug 3 located above the oil cylinder barrel 5 is threadedly connected to the housing 20 and fixedly connected by a lock washer 2. An internal guide screw 37 inside the oil cylinder barrel 5 is fastened to the inner wall of the oil cylinder barrel 5 by a thread at the top. One end of a spring 36 is sleeved on the guide screw 37, and the other end of the spring 36 is located inside a push cover 35. The push cover 35 is threadedly connected to the piston rod 17. Steel balls 4 are located inside the cavity of the push cover 35 under the action of the spring 36 to form a one-way valve. A top block 7 pushes open the steel balls 4 under the action of hydraulic oil, so that the hydraulic oil in the left-side oil cylinder fully returns to the (oil return port) joint C21 to ensure the smooth replacement of the hob.

[0020] The working principle of the rotary joint for the high-speed dry-cutting hobbing machine of the present invention is as follows:

[0021] During the hobbing cutter tightening process, the hydraulic oil passes through the joint A11 (cutter tightening oil inlet) to push the steel ball 4 and enter the left oil cavity of the cylinder barrel 5, thereby pushing the middle piston rod 17 to achieve the tightening action of the hobbing cutter;

[0022] During the process of replacing the hobbing cutter (hobbing cutter relaxation state), the hydraulic oil passes through the joint B12 (cutter relaxation oil inlet) and enters the right oil cavity of the cylinder barrel 5 to push the middle piston rod 17 to achieve the relaxation of the hobbing cutter.

[0023] In order to prevent the hydraulic pressure in the left cylinder barrel 5 of the oil cylinder from not being discharged to the joint C21 (oil return port) in time, small holes are machined on the piston rod 17. After the right side of the cylinder barrel 5 is filled with hydraulic oil, the push block 7 is pushed through the small holes. Under the action of the hydraulic oil, the push block 7 pushes open the steel ball 4, so that the hydraulic oil in the left oil cylinder fully returns to the oil outlet hole 21 to ensure the smooth replacement of the hobbing cutter.

[0024] Since the rotary oil cylinder housing 20 at the tail end and the hob headstock are fixed by an anti-rotation mechanism and are in a relatively static state, it can be ensured that the rotary joint will not rotate randomly in the hobbing cutter tightening and relaxation states.

[0025] The rotary joint at the tail end uses deep groove ball bearings A15 and deep groove ball bearings B22 on both sides to avoid the eccentric contact of the sealing lips of the oil seal. During rotation, the dynamic coaxiality deviation can be reduced, and the coaxiality of the front and rear ends can be ensured at high rotational speeds, thereby ensuring the tight fit of the sealing ring A10 and the sealing ring B18 with the middle piston rod 17, and finally achieving the effect of sealing the hydraulic oil.

Claims

1. Rotary joint for high-speed dry cutting hobbing machine, characterized in that: It includes a cylinder barrel (5), a piston rod (17) is coaxially arranged at the center of the cylinder barrel (5), a piston cover (8) is arranged at one end of the cylinder barrel (5), one end of the piston rod (17) extends into the cylinder barrel (5), and the other end of the piston rod (17) passes through the piston cover (8) and extends into the housing (20). A cover (14) is connected to the housing (20). A joint A (11) and a joint B (12) are respectively arranged on one side of the housing (20), and a joint C (21) is arranged on the other side of the housing (20). A cavity is provided between the cylinder barrel (5) and the piston rod (17), and a one-way valve assembly is arranged in this cavity. A connecting cover (1) is arranged at the other end of the cylinder barrel (5); The piston rod (17) is in a free state inside the front cylinder barrel (5). An STU retaining ring B (27), an O-ring D (28), and an STU retaining ring C (29) are successively arranged at the contact position between the piston rod (17) and the inner wall of the cylinder barrel (5). The piston rod (17) and the cylinder barrel (5) are connected by hexagon head screws (30). A sleeve (31) is coaxially arranged on the hexagon head screws (30). Two oil guiding grooves are formed on the piston rod (17), and an oil plug B (32) and an oil plug C (34) are respectively arranged on the two oil guiding grooves; A sealed oil cavity is formed between the piston cover (8) and the cylinder barrel (5). The seal ring C (9), the STU retaining ring A (24), and the O-ring C (26) arranged at the piston cover (8) are combined to seal the sealed oil cavity; The one-way valve assembly is located in the sealed oil cavity. The one-way valve assembly includes a spring (36). One end of the spring (36) is sleeved on a guide screw (37), and the guide screw (37) is threadedly fastened to the inner wall of the cylinder barrel (5). The other end of the spring (36) is located inside a push cover (35). The push cover (35) is threadedly connected to the piston rod (17). A steel ball (4) is located in the inner cavity of the push cover (35) under the action of the spring (36) to form a one-way valve.

2. The rotary joint for a high-speed dry hobbing machine according to claim 1, characterized in that: The two opposite sides of the housing (20) are respectively assembled on the piston rod (17) through a deep groove ball bearing A (15) and a deep groove ball bearing B (22).

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