CN111037320A

CN111037320A - Oil cylinder type automatic up-down tool changing spindle and tool changing method thereof

Info

Publication number: CN111037320A
Application number: CN201911421321.8A
Authority: CN
Inventors: 叶茂丰
Original assignee: Quanzhou Shengyu Machinery Equipment Co ltd
Current assignee: Quanzhou Shengyu Machinery Equipment Co ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-04-21

Abstract

The invention discloses an oil cylinder type automatic up-down tool changing spindle and a tool changing method thereof, wherein when a spindle is used for tool changing, oil is fed from an oil feeding seat, an oil cylinder piston is pushed to move forwards through oil pressure, a piston rod of the oil cylinder piston pushes a pull rod to move forwards, a pull claw is enabled to extend forwards, and an original tool is loosened and falls off; when the piston rod of the oil cylinder piston pushes the pull rod, the piston rod of the oil cylinder piston is subjected to the elastic force of the belleville spring, so that the oil cylinder body, the piston connecting sleeve, the connecting bracket and the tensioning piece are integrally moved backwards, and the tensioning piece pulls the pull shaft nut at the rear end of the mandrel backwards to reduce the stress of the front bearing and the rear bearing. The movable oil cylinder is composed of the oil cylinder body, the oil cylinder piston, the piston connecting sleeve, the oil cylinder outer cover, the spring and the like, when a tool is changed, the mandrel is subjected to a backward pulling force, the stress of the bearing is greatly reduced (can reach more than 90%), the service life of the bearing is greatly prolonged, and the working precision of the main shaft is effectively ensured.

Description

Oil cylinder type automatic up-down tool changing spindle and tool changing method thereof

Technical Field

The invention belongs to the technical field of spindles, and particularly relates to an oil cylinder type automatic up-down tool changing spindle and a tool changing method thereof.

Background

The electric main shaft is a new technology which integrates a machine tool main shaft and a main shaft motor into a whole and appears in the field of numerical control machine tools, and the electric main shaft, a linear motor technology and a high-speed cutter technology can push high-speed processing to a new era. At present, when a machine tool is used for changing a tool, the force of an oil cylinder piston acts on a pull rod to force a belleville spring to deform, the pull rod moves forwards, a pull claw loosens the tool, and the acting force is transmitted to a shell through a bearing through a mandrel. The bearing is easily damaged due to the large acting force of the oil cylinder piston and frequent acting on the bearing, the service life of the bearing is greatly shortened, and the working precision of the main shaft is reduced.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide an oil cylinder type automatic tool changing spindle capable of reducing bearing stress and a tool changing method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme: an oil cylinder type automatic vertical tool changing spindle comprises a shell, a mandrel, a rear big cover and an oil cylinder, wherein the rear big cover is fixed at the rear end of the shell, the front part of the mandrel is rotatably installed in the shell through a front bearing, the rear part of the mandrel is rotatably installed in the rear big cover through a rear bearing, an axial through hole is formed in the center of the mandrel, a pull rod penetrates through the axial through hole in a sliding manner, a disc spring enabling the pull rod to reset backwards is installed in the rear part of the axial through hole, a pull claw is installed at the front end of the pull rod, a piston rod of the oil cylinder is located right behind the pull rod, the oil cylinder comprises an oil cylinder body, an oil cylinder piston, a piston connecting sleeve and an oil cylinder outer cover, the piston connecting sleeve is fixed at the rear side of a connecting support, the connecting support is fixed at the rear side of a tensioning piece, the tensioning piece is slidably embedded in the rear end of the rear big cover, a pull shaft nut which is pulled when, the utility model discloses a piston assembly, including piston adapter sleeve, hydro-cylinder cover, piston connection cover, hydro-cylinder body, piston connection cover, hydro-cylinder cover and hydro-cylinder body, the hydro-cylinder body fix the rear side of piston connection cover and cover piston connection cover and hydro-cylinder body in the slip chamber of formation between the rear side of piston connection cover and the piston connection cover, be provided with a plurality of evenly distributed's spring between the rear end of hydro-cylinder cover and hydro-cylinder body, the inlet port has been seted up at the rear end center of hydro-cylinder body, the inlet port is connected with the oil.

Preferably, a first central air passage is arranged at the center of the pull rod, a slot is arranged at the rear end of the first central air passage, a plug inserted into the slot is arranged at the piston rod end of the oil cylinder piston, a first axial air passage is arranged on the side wall of the oil cylinder body, an air inlet seat is connected with the rear end air inlet of the first axial air passage, the air inlet seat penetrates through the outer cover of the oil cylinder in a sliding manner, a first transition air passage communicated with the front end air outlet of the first axial air passage is arranged on the piston connecting sleeve, an air inlet ring groove is arranged on the periphery of the middle part of the piston rod, the air inlet ring groove is aligned with the air outlet of the first transition air passage when the piston rod is completely extended out, a first radial air passage communicated with the air inlet ring groove is arranged at the middle part of the piston rod, a second central air passage communicated with the first radial, the second central air passage penetrates through the plug and is opposite to the first central air passage.

Preferably, a plurality of front spring seat holes are uniformly distributed in the rear end face of the oil cylinder body, a plurality of rear spring seat holes corresponding to the front spring seat holes are formed in the oil cylinder outer cover, and the front end and the rear end of the spring are respectively embedded into the front spring seat holes and the rear spring seat holes.

Preferably, still include interior snap ring, preceding nut, oil baffle lid, atmoseal ring and preceding sealed lid, interior snap ring is installed in the front end of casing and is withstood terminal surface before the outer lane of front bearing, preceding nut is fixed to be locked on the anterior external screw thread of dabber, the front end at the casing is fixed to the oil baffle lid, the atmoseal ring is fixed in the front side central groove of oil baffle lid, the front side at the atmoseal ring is fixed to preceding sealed lid, preceding nut respectively with oil baffle lid, atmoseal ring clearance fit.

Preferably, a second axial air passage is formed in the side wall of the shell and penetrates through the front end face and the rear end face of the cylindrical shell, a second transition air passage is formed in the oil blocking cover, the rear end of the second transition air passage is communicated with the front end of the second axial air passage, a second radial air passage is formed in the air sealing ring, the outer end of the second radial air passage is communicated with the front end of the second transition air passage, an air outlet communicated with the inner end of the second radial air passage is formed in the front end face of the air sealing ring, and the air outlet faces towards the inner edge of the rear side of the front sealing cover.

Preferably, the rotary encoder further comprises a steel ball retainer, a bearing seat, a rear nut and a rear sealing cover, wherein the rear periphery of the mandrel passes through the rear bearing and is installed in the bearing seat, the bearing seat penetrates through the front end of the rear big cover, the steel ball retainer is arranged between the front periphery of the bearing seat and the front inner periphery of the rear big cover, the rear nut is fixedly locked on the rear external thread of the mandrel to prop against the inner ring rear end face of the rear bearing, the rear sealing cover is fixedly installed in the rear end of the bearing seat and covers the rear bearing, an encoder magnetic ring is fixedly sleeved on the rear end periphery of the mandrel, and an encoder reading head matched with the encoder magnetic ring is fixed on the bearing seat.

Preferably, the fixed cover in rear end portion periphery of pull rod is equipped with induction nut, the inside wall of back connection lid is installed and is responded to nut matched with proximity switch.

Preferably, the fixed cover in middle part periphery of dabber is equipped with rotor and two short circuit rings that are located the rotor both ends respectively, the fixed stator that is equipped with in the middle part of the inner chamber of casing around outside the rotor that inlays.

Preferably, the rear connecting cover is provided with a power line outlet.

The invention also provides a tool changing method of the oil cylinder type automatic up-down tool changing spindle, when changing tools, oil is fed from the oil inlet seat, the oil cylinder piston is pushed to move forwards through oil pressure, the piston rod of the oil cylinder piston pushes the pull rod to move forwards, so that the pull claw extends forwards, and the original tool is loosened and falls off; when the piston rod of the oil cylinder piston pushes the pull rod, the piston rod of the oil cylinder piston is subjected to the elastic force of the belleville spring, so that the oil cylinder body, the piston connecting sleeve, the connecting bracket and the tensioning sheet integrally move backwards under the action of the counter-acting force of the pull rod, and the tensioning sheet pulls the pull shaft nut at the rear end of the mandrel backwards so as to reduce the stress of the front bearing and the rear bearing; after the pulling claw grabs a new tool, oil in the sliding cavity flows out of the oil inlet seat and is released, the pull rod retracts backwards under the action of the disc spring, the pull rod pushes the oil cylinder piston to move backwards and return, meanwhile, the pulling claw retracts backwards, and the new tool is clamped and fixed.

Compared with the prior art, the invention has the following beneficial effects: the movable oil cylinder is composed of the oil cylinder body, the oil cylinder piston, the piston connecting sleeve, the oil cylinder outer cover, the spring and the like, and the pull shaft nut is pulled backwards through the oil cylinder piston, the oil cylinder body, the piston connecting sleeve, the connecting support and the tensioning piece when a tool is changed, so that the mandrel is subjected to the force of pulling backwards, the stress of the bearing is greatly reduced (can reach more than 90%), the service life of the bearing is greatly prolonged, and the working precision of the main shaft is effectively guaranteed.

Drawings

Fig. 1 is a sectional view showing the overall structure of an embodiment of the present invention.

Fig. 2 is a sectional view of a front structure of an embodiment of the present invention.

Fig. 3 is a sectional view of a rear structure of the embodiment of the present invention.

The labels in the figure are: 1. a housing; 2. a mandrel; 3. a rear big cover; 4. a front bearing; 5. a rear bearing; 6. a pull rod; 7. a cylinder block; 8. a cylinder piston; 9. a piston connecting sleeve; 10. an oil cylinder outer cover; 11. connecting a bracket; 12. a tension sheet; 13. pulling the shaft nut; 14. a rear connecting cover; 15. an oil inlet seat; 16. a first central air passage; 17. a slot; 18. a plug; 19. a seal ring; 20. a first axial air passage; 21. an air inlet seat; 22. sealing the framework; 23. a first transition gas duct; 24. an air inlet ring groove; 25. a first radial gas passage; 26. a second central air passage; 27. an inner snap ring; 28. a front nut; 29. an oil blocking cover; 30. an air seal ring; 31. a front sealing cover; 32. a second axial air passage; 33. a second transition gas duct; 34. a second radial gas passage; 35. an air outlet; 36. a steel ball retainer; 37. a bearing seat; 38. a back nut; 39. a rear sealing cover; 40. an encoder magnetic ring; 41. an encoder readhead; 42. an induction nut; 43. a proximity switch; 44. a power line outlet; 45. a rotor; 46. a stator; 47. a flange; 48. a first lock nut; 49. a second lock nut; 50. a spring.

Detailed Description

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

As shown in fig. 1 to 3, the present embodiment provides an oil cylinder type automatic tool changing spindle capable of changing tools up and down, which includes a housing 1, a mandrel 2, a rear large cover 3 and an oil cylinder, where the rear large cover 3 is fixed at the rear end of the housing 1, the front portion of the mandrel 2 is rotatably installed in the housing 1 through front bearings 4 (specifically, two front bearings 4 are provided between the two front bearings 4, an inner ring of the front bearing 4 is positioned by a step of the mandrel 2, an inner ring of the rear bearing 4 is positioned by a first lock nut 48, an outer ring of the rear bearing 4 is positioned by an inner flange of the housing 1), the rear portion of the mandrel 2 is rotatably installed in the rear large cover 3 through rear bearings 5 (specifically, two rear bearing 5 are provided between the two rear bearings) and an axial through hole is formed in the center of the mandrel 2, a pull rod 6 is slidably inserted in the axial through hole, a disc spring (omitted in the drawing) for returning the pull rod 6 back is installed in the rear portion of the axial through hole, the front end of the pull rod 6 is provided with a pulling claw (omitted in the figure), a piston rod of the oil cylinder is positioned right behind the pull rod 6, the oil cylinder comprises an oil cylinder body 7, an oil cylinder piston 8, a piston connecting sleeve 9 and an oil cylinder outer cover 10, the piston connecting sleeve 9 is fixed at the rear side of a connecting support 11, the connecting support 11 is fixed at the rear side of a tensioning sheet 12, the tensioning sheet 12 is embedded in the rear end of a rear big cover 3 in a sliding manner, the rear end of the mandrel 2 is fixed with a pulling shaft nut 13 which is pulled when the tensioning sheet 12 moves backwards, the oil cylinder body 7 is fixed at the rear side of the piston connecting sleeve 9 and forms a sliding cavity with the piston connecting sleeve 9, the oil cylinder piston 8 is installed in the sliding cavity in a sliding manner, the piston rod of the oil cylinder piston 8 penetrates through the piston connecting sleeve 9 in a sliding manner, the rear side of the rear big cover 3 is fixed with a rear connecting cover 14, the oil cylinder outer cover 10 is fixed at the rear side of, be provided with a plurality of evenly distributed's spring 50 between the rear end of hydro-cylinder dustcoat 10 and hydro-cylinder body 7, the inlet port has been seted up at the rear end center of hydro-cylinder body 7, the inlet port is connected with oil feed seat 15, oil feed seat 15 slides and runs through out hydro-cylinder dustcoat 10, can install the skeleton seal 22 with oil feed seat 15 sliding contact on the hydro-cylinder dustcoat 10. In order to position the spring 50 conveniently, a plurality of front spring seat holes which are uniformly distributed are formed in the rear end face of the oil cylinder body 7, a plurality of rear spring seat holes corresponding to the front spring seat holes are formed in the oil cylinder outer cover 10, the front end and the rear end of the spring 50 are embedded into the front spring seat holes and the rear spring seat holes respectively, and the oil cylinder body 7, the piston connecting sleeve 9, the connecting support 11 and the tensioning piece 12 can be reset after tool changing through the spring 50.

In this embodiment, in order to facilitate cooling of the tool during tool changing, a first central air passage 16 is formed in the center of the pull rod 6, a slot 17 is formed in the rear end of the first central air passage 16, a plug 18 for being inserted into the slot 17 is arranged at the piston rod end of the oil cylinder piston 8, an annular sealing groove located on the outer peripheral side of the plug 18 is formed in the end surface of the piston rod, a sealing ring 19 is installed in the annular sealing groove, and the sealing ring 19 is in sealing contact with the rear end surface of the pull rod 6 when the plug 18 is completely inserted into the slot 17, so as to prevent air leakage, although the sealing ring 19 may also be arranged on the rear end surface of; a first axial air passage 20 is arranged on the side wall of the oil cylinder body 7, an air inlet seat 21 is connected with an air inlet at the rear end of the first axial air passage 20, the air inlet seat 21 penetrates through the oil cylinder outer cover 10 in a sliding manner, a framework seal 22 in sliding contact with the air inlet seat 21 can be installed on the oil cylinder outer cover 10, the piston connecting sleeve 9 is provided with a first transition air passage 23 communicated with an air outlet at the front end of the first axial air passage 20, an air inlet ring groove 24 is arranged on the periphery of the middle part of the piston rod, the air inlet ring groove 24 is aligned with the air outlet of the first transition air passage 23 when the piston rod is completely extended out, the middle part of the piston rod is provided with a first radial air passage 25 communicated with the air inlet ring groove 24, the center of the front end of the piston rod is provided with a second central air passage 26 communicated with the first radial air passage 25, and the second central air passage 26 penetrates through the plug 18 and is opposite to the first central air passage 16. When the piston rod extends forwards completely, cooling air enters from the air inlet seat 21, passes through the first axial air passage 20, the first transition air passage 23, the air inlet ring groove 24, the first radial air passage 25, the second central air passage 26 and the second central air passage 26 in sequence and then is discharged from the pull claw, and the cutter is cooled.

In this embodiment, the main shaft further includes an inner snap ring 27, a front nut 28, an oil blocking cover 29, an air sealing ring 30 and a front sealing cover 31, the inner snap ring 27 is installed in the front end of the housing 1 and abuts against the front end face of the outer ring of the front bearing 4, the front nut 28 is fixedly locked on the front external thread of the mandrel 2, the oil blocking cover 29 is fixed at the front end of the housing 1, the air sealing ring 30 is fixed in a central groove at the front side of the oil blocking cover 29, the front sealing cover 31 is fixed at the front side of the air sealing ring 30, the front nut 28 is in clearance fit with the oil blocking cover 29 and the air sealing ring 30 respectively and forms a circuitous structure, thereby effectively preventing impurities such as dust and cooling water from entering the front end of the housing 1, avoiding the front bearing 4 from being polluted and damaged, and prolonging the service life of the front bearing 4. A second axial air passage 32 is formed in the side wall of the shell 1, the second axial air passage 32 penetrates through the front end face and the rear end face of the cylindrical shell 1, a second transition air passage 33 is formed in the oil blocking cover 29, the rear end of the second transition air passage 33 is communicated with the front end of the second axial air passage 32, a second radial air passage 34 is formed in the air sealing ring 30, the outer end of the second radial air passage 34 is communicated with the front end of the second transition air passage 33, an air outlet 35 communicated with the inner end of the second radial air passage 34 is formed in the front end face of the air sealing ring 30, and the air outlet 35 faces the inner edge of the rear side of the front sealing cover 31 obliquely. When the main shaft works, compressed air is sprayed out from the air outlet 35 after sequentially passing through the second axial air passage 32, the second transition air passage 33 and the second radial air passage 34, so that impurities such as dust, cooling water and the like are effectively prevented from entering the shell 1 from a gap between the front sealing cover 31 and the mandrel 2.

In this embodiment, the main shaft further includes a steel ball retainer 36, a bearing seat 37, a rear nut 38 and a rear sealing cover 39, the rear outer periphery of the spindle 2 is installed in the bearing seat 37 through the rear bearings 5 (specifically, two rear bearings 5 are provided with a rear spacer ring therebetween, the inner ring of the front rear bearing 5 is positioned by a spacer ring which is positioned by a step of the spindle 2, the outer ring of the front rear bearing 5 is positioned by the inner flange of the bearing seat 37), the bearing seat 37 is inserted into the front end of the rear large cover 3, the steel ball retainer 36 (on which a plurality of steel balls are distributed in an array along the axial direction and the circumferential direction so that the bearing seat 37 and the rear large cover 3 can slide back and forth relatively, and the stress of the rear bearings 5 can be reduced) is arranged between the front outer periphery of the bearing seat 37 and the front inner periphery of the rear large cover 3, the rear nut 38 is fixedly locked on the rear external thread of the spindle 2 to abut against the rear end, the rear sealing cover 39 is fixedly installed in the rear end of the bearing seat 37 and covers the rear bearing 5, which is beneficial to preventing dust from polluting the rear bearing 5; an encoder magnetic ring 40 is fixedly sleeved on the periphery of the rear end of the mandrel 2, an encoder reading head 41 matched with the encoder magnetic ring 40 is fixed on the bearing seat 37, and the number of times of rotation of the mandrel 2 can be read through the encoder reading head 41.

In this embodiment, the fixed cover in rear end portion periphery of pull rod 6 is equipped with induction nut 42, the inside wall of back connection cover 14 is installed and is responded to nut 42 matched with proximity switch 43 (its model is unlimited, optional present ripe product), and when pull rod 6 concertina movement triggered proximity switch 43, proximity switch 43 produced the signal of an automatic tool changing. In order to conveniently lead out the power cord of the encoder, a power cord outlet 44 is formed in the rear connecting cover 14, and the power cord of the encoder is led out from the power cord outlet 44 after passing through the tension sheet 12.

In this embodiment, the rotor 45 and two short-circuit rings respectively located at two ends of the rotor 45 are fixedly sleeved on the periphery of the middle part of the mandrel 2, two ends of the short-circuit rings are respectively located by a front retainer ring and a rear retainer ring, the front retainer ring is located by a step of the mandrel 2, and the rear retainer ring is fixed by a second lock nut 49; the middle part of the inner cavity of the shell 1 is fixedly embedded with a stator 46 surrounding the rotor 45, and the rotor 45 and the stator 46 form a motor, thereby forming an electric spindle. In addition, the periphery of the front part of the shell 1 is provided with a flange 47, and a plurality of bolt holes which are uniformly distributed are formed in the flange 47, so that the main shaft can be conveniently and fixedly installed through fasteners.

The embodiment also provides a tool changing method of the oil cylinder type automatic up-down tool changing spindle, when a tool is changed, oil is fed from the oil feeding seat 15, the oil cylinder piston 8 is pushed to move forwards through oil pressure, the piston rod of the oil cylinder piston 8 pushes the pull rod 6 to move forwards, so that the pull claw extends forwards, and the original tool is loosened and falls off; when the piston rod of the oil cylinder piston 8 pushes the pull rod 6, the pull rod 6 is under the elastic force action of the belleville spring, so that the piston rod of the oil cylinder piston 8 is under the reaction force of the pull rod 6, the oil cylinder body 7, the piston connecting sleeve 9, the connecting bracket 11 and the tensioning sheet 12 integrally move backwards, and the tensioning sheet 12 pulls the pull shaft nut 13 at the rear end of the mandrel 2 backwards, so that the stress of the front bearing 4 and the rear bearing 5 is reduced (can reach more than 90 percent), and the service life of the bearing is greatly prolonged; after the new tool is grabbed by the pulling claw (for example, the new tool is automatically grabbed by the pulling claw by using an external manipulator), oil in the sliding cavity flows out from the oil inlet seat 15 and is released, the pull rod 6 retracts backwards under the action of the belleville spring, the pull rod 6 pushes the oil cylinder piston 8 to move backwards and return, and meanwhile, the pulling claw retracts backwards, so that the new tool is clamped and fixed.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention in any way, and it should be understood by those skilled in the art that the above embodiments can be modified and equally varied without departing from the technical spirit of the present invention.

Claims

1. The utility model provides an automatic tool changing main shaft from top to bottom of hydro-cylinder formula, includes casing, dabber, back big lid and hydro-cylinder, the rear end at the casing is fixed to back big lid, the front portion of dabber is rotated through the front bearing and is installed in the casing, the rear portion of dabber is rotated through the back bearing and is installed in the big lid of back, the axial through hole has been seted up at the center of dabber, it wears to be equipped with the pull rod to slide in the axial through hole, install the belleville spring that makes the pull rod reset backward in the rear portion of axial through hole, the front end of pull rod is installed and is drawn the claw, the piston rod of hydro-cylinder is: the oil cylinder comprises an oil cylinder body, an oil cylinder piston, a piston connecting sleeve and an oil cylinder outer cover, the piston connecting sleeve is fixed at the rear side of the connecting bracket, the connecting bracket is fixed at the rear side of the tensioning piece, the tensioning piece is slidably embedded in the rear end of the rear big cover, the rear end of the mandrel is fixed with a pull shaft nut which is pulled when the tensioning piece moves backwards, the oil cylinder body is fixed at the rear side of the piston connecting sleeve and forms a sliding cavity with the piston connecting sleeve, the oil cylinder piston is slidably arranged in the sliding cavity, a piston rod of the oil cylinder piston slidably penetrates through the piston connecting sleeve, the rear side of the rear big cover is fixed with the rear connecting cover, the oil cylinder outer cover is fixed at the rear side of the rear connecting cover and covers the piston connecting sleeve and the oil cylinder body, a plurality of uniformly distributed springs are arranged between the oil cylinder outer cover and the rear end of the oil cylinder body, and an oil inlet hole is, the oil inlet hole is connected with an oil inlet seat, and the oil inlet seat penetrates through the outer cover of the oil cylinder in a sliding mode.

2. The oil cylinder type automatic tool changing spindle according to claim 1, characterized in that: a first central air passage is arranged in the center of the pull rod, a slot is arranged at the rear end of the first central air passage, the piston rod end of the oil cylinder piston is provided with a plug which is inserted into the slot, the side wall of the oil cylinder body is provided with a first axial air passage, an air inlet seat is connected with an air inlet at the rear end of the first axial air passage and penetrates through the outer cover of the oil cylinder in a sliding manner, the piston connecting sleeve is provided with a first transition air passage communicated with an air outlet at the front end of the first axial air passage, the periphery of the middle part of the piston rod is provided with an air inlet ring groove which is aligned with the air outlet of the first transition air passage when the piston rod is completely extended out, the middle part of the piston rod is provided with a first radial air passage communicated with the air inlet ring groove, the center of the front end of the piston rod is provided with a second central air passage communicated with the first radial air passage, and the second central air passage penetrates through the plug and is opposite to the first central air passage.

3. The oil cylinder type automatic tool changing spindle according to claim 1, characterized in that: the rear end face of the oil cylinder body is provided with a plurality of uniformly distributed front spring seat holes, the oil cylinder outer cover is internally provided with a plurality of rear spring seat holes corresponding to the front spring seat holes, and the front end and the rear end of the spring are respectively embedded into the front spring seat holes and the rear spring seat holes.

4. The oil cylinder type automatic tool changing spindle according to claim 1, characterized in that: the oil seal structure is characterized by further comprising an inner clamping ring, a front nut, an oil blocking cover, an air seal ring and a front seal cover, wherein the inner clamping ring is installed in the front end of the shell and abuts against the front end face of the outer ring of the front bearing, the front nut is fixedly locked on the front external thread of the mandrel, the oil blocking cover is fixed at the front end of the shell, the air seal ring is fixed in a front side central groove of the oil blocking cover, the front seal cover is fixed at the front side of the air seal ring, and the front nut is in clearance fit with the oil blocking cover and the air seal ring respectively.

5. The oil cylinder type automatic tool changing spindle according to claim 4, characterized in that: the utility model discloses a gas seal ring, including the casing, the casing is provided with the lateral wall of casing, second axial air flue runs through the front and back terminal surface of tube-shape casing, the second transition air flue has been seted up in the oil baffle lid, the rear end of second transition air flue communicates with the front end of second axial air flue, the radial air flue of second has been seted up in the gas seal ring, the outer end of the radial air flue of second communicates with the front end of second transition air flue, the gas outlet that is linked together with the radial air flue inner is seted up to the preceding terminal surface of gas seal ring, the gas outlet is towards the rear side inner edge department of.

6. The oil cylinder type automatic tool changing spindle according to claim 1, characterized in that: the rear end of the mandrel is installed in the bearing seat through the rear bearing, the bearing seat penetrates through the front end of the rear big cover, the steel ball retainer is arranged between the front portion outer periphery of the bearing seat and the front portion inner periphery of the rear big cover, the rear nut is fixedly locked on the rear portion external threads of the mandrel to abut against the inner ring rear end face of the rear bearing, the rear sealing cover is fixedly installed in the rear end of the bearing seat and covers the rear bearing, an encoder magnetic ring is fixedly sleeved on the rear end portion outer periphery of the mandrel, and an encoder reading head matched with the encoder magnetic ring is fixed on the bearing seat.

7. The oil cylinder type automatic tool changing spindle according to claim 1, characterized in that: the fixed cover in rear end portion periphery of pull rod is equipped with the induction nut, the inside wall of back connection lid is installed and is responded to nut matched with proximity switch.

8. The oil cylinder type automatic tool changing spindle according to claim 1, characterized in that: the fixed cover in middle part periphery of dabber is equipped with rotor and two short circuit rings that are located the rotor both ends respectively, the fixed stator that is equipped with in the middle part of the inner chamber of casing around outside the rotor that inlays.

9. The oil cylinder type automatic tool changing spindle according to claim 1, characterized in that: and the rear connecting cover is provided with a power line outlet.

10. A tool changing method of an oil cylinder type automatic up and down tool changing spindle according to any one of claims 1 to 9, characterized in that: when the tool is changed, oil is fed from the oil inlet seat, the oil cylinder piston is pushed to move forwards through oil pressure, the piston rod of the oil cylinder piston pushes the pull rod to move forwards, the pull claw extends forwards, and the original tool is loosened and falls off; when the piston rod of the oil cylinder piston pushes the pull rod, the piston rod of the oil cylinder piston is subjected to the elastic force of the belleville spring, so that the oil cylinder body, the piston connecting sleeve, the connecting bracket and the tensioning sheet integrally move backwards under the action of the counter-acting force of the pull rod, and the tensioning sheet pulls the pull shaft nut at the rear end of the mandrel backwards so as to reduce the stress of the front bearing and the rear bearing; after the pulling claw grabs a new tool, oil in the sliding cavity flows out of the oil inlet seat and is released, the pull rod retracts backwards under the action of the disc spring, the pull rod pushes the oil cylinder piston to move backwards and return, meanwhile, the pulling claw retracts backwards, and the new tool is clamped and fixed.