CN212705646U

CN212705646U - Rotating mechanism of tool changing oil cylinder and tool changing mechanism

Info

Publication number: CN212705646U
Application number: CN202021661965.2U
Authority: CN
Inventors: 陈亮
Original assignee: Okada Precision Machinery Changzhou Co ltd
Current assignee: Okada Precision Machinery Changzhou Co ltd
Priority date: 2020-08-11
Filing date: 2020-08-11
Publication date: 2021-03-16
Anticipated expiration: 2030-08-11

Abstract

The utility model discloses a rotating mechanism of a tool changing oil cylinder and a tool changing mechanism, which comprises an annular shell which is annularly sleeved on the outer wall of the tool changing oil cylinder, and set up the first circulation oil circuit on annular housing, set up the rotatory oil pocket that is annular recess column structure on annular housing's the inner wall, the both ends of annular groove are equipped with rotary seal mechanism, annular housing fixes on the outer wall of tool changing hydro-cylinder through each rotary seal mechanism, be equipped with the rotor with annular groove cross-section looks adaptation on the part that the outer wall of tool changing hydro-cylinder corresponds with annular groove, first circulation oil circuit is linked together with annular groove, oil feed drive rotor is at the annular groove internal rotation in annular groove, the rotor drives the whole rotation of tool changing hydro-cylinder, regard the whole axis of rotation of tool changing hydro-cylinder, need not to add other slewing mechanism again, very big appearance that has reduced whole tool changing mechanism, the application range is enlarged.

Description

Rotating mechanism of tool changing oil cylinder and tool changing mechanism

Technical Field

The utility model relates to a digit control machine tool technical field especially relates to a rotary mechanism and tool changing mechanism of tool changing hydro-cylinder.

Background

In the prior art, a cutter for a spindle of a numerical control machine tool generally adopts manual cutter changing, or a cutter holder is arranged at a head of the machine tool, so that the cutter changing time is long and the efficiency is low. Patent document CN204353858U discloses a rotatory tool changing mechanism of aircraft nose disc type, the cover has the sheave on its center pin, the one end of center pin still is fixed with the tool magazine, the shifting shaft is by motor drive, the one end of shifting shaft still is equipped with the toggle roller with the sheave meshing, the tool magazine includes a plurality of tool holders that set up on disc type blade disc and the disc type blade disc circumference, rotatory tool changing mechanism of aircraft nose disc type moves along with the mechanism, the main shaft only needs Z to remove during the tool changing, can realize more quick automatic tool changing, but the setting of a plurality of tool holders that set up on disc type blade disc and the disc type blade disc circumference has inevitable increased whole tool changing mechanism's structure, make tool changing mechanism fully limited in the use.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a rotary mechanism and tool changing mechanism of tool changing hydro-cylinder to solve the problem that above-mentioned prior art exists, the tool changing hydro-cylinder directly combines together with rotatory oil pocket as the rotation axis, very big appearance that has reduced whole tool changing mechanism has reduced usage space, has enlarged application range.

In order to achieve the above object, the utility model provides a following scheme: a rotating mechanism of a tool changing oil cylinder comprises an annular shell sleeved on the outer wall of the tool changing oil cylinder in a ring mode and a first circulating oil path arranged on the annular shell, wherein a rotating oil cavity in an annular groove-shaped structure is formed in the inner wall of the annular shell, rotating sealing mechanisms are arranged at two ends of an annular groove, the annular shell is fixed on the outer wall of the tool changing oil cylinder through the rotating sealing mechanisms, a rotor matched with the section of the annular groove is arranged on the outer wall of the tool changing oil cylinder and the part, corresponding to the annular groove, of the outer wall of the tool changing oil cylinder, the first circulating oil path is communicated with the annular groove, oil in the annular groove drives the rotor to rotate in the annular groove, and the rotor drives the tool changing oil cylinder to rotate integrally;

the inner wall of the annular groove is detachably connected with a stator matched with the section of the annular groove, the rotor rotates on two sides of the stator in a reciprocating mode, and when the rotor contacts the stator, the rotor stops rotating.

Preferably, first circulation oil circuit includes that two pairs are seted up on the annular housing inner wall and be located the oil through hole of stator both sides, it is every right the oil through hole includes main oil through hole and vice oil through hole, vice oil through hole is located main oil through hole with between the stator and be close to the stator, just main oil through hole with vice oil through hole is less than along circumference's interval the length of rotor, the aperture of vice oil through hole is less than main oil through hole is used for the rotor is close to only pass through when the stator vice oil through hole oil return is in order to slow down oil return rate.

Preferably, two ends of the rotor, which are close to one side of the annular shell, are respectively provided with a notch, and when the rotor is contacted with the stator, the auxiliary oil through hole is positioned in the notches.

Preferably, be equipped with two on the annular casing with each the buffer block that vice oilhole corresponds, first circulation oil circuit including set up respectively in each the buffer block and respectively with the circulation branch road of vice oilhole intercommunication, the circulation branch road includes oil feed branch road and oil return branch road, be equipped with steel ball, first compression spring and sprue in the oil feed branch road along the oil feed direction in proper order, the steel ball passes through first compression spring shutoff is in the oil feed end of oil feed branch road is used for forming the check valve effect, the connection can be dismantled to the sprue on the buffer block and the shutoff is in the tip of oil feed branch road, be equipped with the buffer screw in the oil return branch road.

Preferably, a telescopic oil cavity which is a through structure is formed in the tool changing oil cylinder, a piston rod penetrates through the telescopic oil cavity, one end of the piston rod extends out of the tool changing oil cylinder and is connected with a tool arm, a second circulating oil path communicated with the telescopic oil cavity is formed in the side wall of the tool changing oil cylinder, the telescopic oil cavity is driven by the oil of the second circulating oil path to stretch along the axial direction, and the piston rod drives the tool arm to realize the functions of tool pulling and tool inserting.

Preferably, a plurality of limiting blocks are fixed on the annular shell, limiting bolts and inductive switches are arranged on the limiting blocks, a rotary collision block matched with the limiting blocks is fixed on the tool changing oil cylinder, the tool changing oil cylinder drives the rotary collision block to rotate to be in contact with the limiting bolts and then stop, and the inductive switches output signals in place.

Preferably, the flexible oil intracavity is followed the direction that the piston rod stretches out is fixed with lid, transition axle and hydro-cylinder protecgulum behind the hydro-cylinder, the hydro-cylinder protecgulum is equipped with and is used for the first through-hole that the piston rod wore to establish, just the piston rod with form sliding seal between the first through-hole, the part that the piston rod is located in the tool changing hydro-cylinder is connected with the piston, the piston is located the transition axle with between the hydro-cylinder protecgulum, just the outer wall of piston with form sliding seal between the inner wall of flexible oil pocket.

Preferably, the outer edge of the oil cylinder rear cover is detachably connected to one end of the annular shell, the oil cylinder rear cover extends towards the tool changing oil cylinder side to form a flange matched with the telescopic oil cavity, and the flange penetrates through the telescopic oil cavity and forms sliding seal with the inner wall of the telescopic oil cavity.

Preferably, be equipped with the telescopic link in the tool changing hydro-cylinder, lid behind the hydro-cylinder with the center of transition axle is all offered and is used for the second through-hole that the telescopic link wore to establish, the piston rod is close to the one end of transition axle seted up with the bar recess of telescopic link adaptation, the telescopic link is including stretching out respectively the transition axle with flexible section and the back lid section of lid behind the hydro-cylinder, flexible section is worn to establish and is restricted in the bar recess, install the signal ring on the back lid section, cover behind the hydro-cylinder be equipped with the sword inductive switch that pulls out that the signal ring matches, be equipped with on the annular housing with the signal trades the sword inductive switch that matches.

Preferably, the end of the telescopic section radially extends to form an annular bulge, the open end of the bar-shaped groove is provided with a telescopic stop dog used for limiting the annular bulge, a second compression spring and a spring retainer ring are sleeved on the telescopic rod in the second through hole, the spring retainer ring is fixed on the outer wall of the telescopic rod, one side, close to the piston rod, of the second through hole is provided with a limiting part used for clamping the second compression spring, and the second compression spring is located between the spring stop dog and the limiting part and used for pushing the telescopic rod to reset.

The utility model discloses for prior art gain following technological effect:

1. the utility model discloses in, be equipped with the rotor with annular groove cross-section looks adaptation on the outer wall of tool changing hydro-cylinder and the part that the annular groove corresponds, oil feed drive rotor is at the annular groove internal rotation in the annular groove, and the rotor drives the whole rotation of tool changing hydro-cylinder, that is to say, the whole axis of rotation of regarding as of tool changing hydro-cylinder, need not to add other slewing mechanism again, very big appearance that has reduced whole tool changing mechanism has enlarged application range.

2. The utility model discloses in, main oil through hole and vice oil through hole are less than the length of rotor along the interval of circumference, and the aperture of vice oil through hole is less than main oil through hole for carry out the shutoff to main oil through hole when the rotor is close to the stator, only through vice oil through hole oil return in order to slow down oil return rate, and then reduced the slew velocity when the rotor is close to the stator, avoid the stator to receive the too big damage that leads to of impact force of rotor.

3. The utility model discloses in, the both ends that the rotor is close to annular housing one side are equipped with the breach respectively, and when the rotor contacted with the stator, vice logical oilhole was located the breach, has avoided vice logical oilhole to have been leaded to rotor and stator can not cooperate when the rotor does not contact the stator by the shutoff to target in place.

4. The utility model discloses in, the circulation branch road includes oil feed branch road and oil return branch road, and the steel ball is used for forming the check valve effect through the inlet end of first compression spring shutoff in the oil feed branch road, is equipped with the buffer screw in the oil return branch road, only passes through the buffer screw when the oil return for oil return speed is abundant limited, can form quick oil feed passageway again through steel ball extrusion spring when the oil feed, has guaranteed the oil feed speed.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a side view of the present invention;

FIG. 2 is a front sectional view of the present invention;

FIG. 3 is a side sectional view of the present invention;

wherein, 1-a knife inserting inductive switch, 2-a switch frame, 3-a limit bolt, 4-a limit block, 5-an inductive switch, 6-a rotary collision block, 7-a bearing, 8-an oil cylinder rear cover, 9-a signal ring installation groove, 10-a groove cover, 11-a signal ring, 12-a telescopic rod, 13-a knife pulling inductive switch, 14-a locking nut, 15-a rear cover, 16-a middle cover, 17-a front cover, 18-a knife changing oil cylinder, 19-a piston rod, 20-an oil cylinder front cover, 21-a telescopic stop block, 22-a second compression spring, 23-a transition shaft, 24-a spring retainer ring, 25-a key block, 26-a buffer screw, 27-a plug, 28-a buffer block, 29-a first compression spring, 30-a steel ball, 31-stator, 32-rotor, 33-dust cover.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The utility model aims at providing a rotary mechanism and tool changing mechanism of tool changing hydro-cylinder 18 to solve the problem that above-mentioned prior art exists, tool changing hydro-cylinder 18 directly combines together as rotation axis and rotatory oil pocket, very big appearance that has reduced whole tool changing mechanism has reduced the usage space, has enlarged application range.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.

As shown in fig. 2 and fig. 3, the utility model provides a rotating mechanism of a tool changing oil cylinder 18, which comprises an annular shell sleeved on the outer wall of the tool changing oil cylinder 18 in an annular manner, and a first circulating oil path arranged on the annular shell, wherein a rotating oil chamber in an annular groove-shaped structure is arranged on the inner wall of the annular shell, two ends of the annular groove are provided with a rotating sealing mechanism, for example, a bearing 7 and a sealing ring are arranged, when a bearing 7 is adopted, a locking nut 14 is preferably arranged outside the bearing 7 to avoid the dislocation of the bearing 7; in order to avoid the rotary sealing mechanism from being easily damaged in the working process, a dustproof cover 33 is arranged on the outer side of the rotary sealing mechanism so as to reduce dust generated in the rack process from sputtering on the rotary sealing mechanism; preferably, the annular housing comprises a front cover 17, a middle cover 16 and a rear cover 15 which are sequentially arranged side by side along the axial direction, the front cover 17, the middle cover 16 and the rear cover 15 are connected together through a detachable mechanism such as a bolt, and the front cover 17 and the rear cover 15 are radially and inwardly protruded out of the inner wall of the middle cover 16, so that an annular groove is formed in a region corresponding to the middle cover 16; the annular shell is fixed on the outer wall of the tool changing oil cylinder 18 through each rotary sealing mechanism, preferably, annular grooves for mounting the bearings 7 are formed in the front cover 17 and the rear cover 15, the bearings 7 are sleeved on the outer wall of the tool changing oil cylinder 18 to ensure that the tool changing oil cylinder 18 rotates in the annular shell, and rotary sealing devices are arranged between the inner walls of the front cover 17 and the rear cover 15 and the tool changing oil cylinder 18 to keep a sealing state in the relative rotation process of the annular shell and the tool changing oil cylinder 18; the rotor 32 matched with the section of the annular groove is arranged on the outer wall of the tool changing oil cylinder 18 and the part corresponding to the annular groove, namely, the annular groove is sleeved on the outer wall of the tool changing oil cylinder 18 in a sleeving manner, the annular groove and the outer wall of the tool changing oil cylinder 18 form a rotary oil cavity, the section of the rotor 32 is matched with the section of the rotary oil cavity, the circumferential length of the rotor is designed according to the rotary requirement of the tool changing oil cylinder 18, then the first circulating oil path is communicated with the annular groove, the rotor 32 is driven to rotate in the annular groove by oil fed in the annular groove, and the rotor 32 drives the tool changing oil cylinder 18 to.

Meanwhile, the inner wall of the annular groove is detachably connected with a stator 31 matched with the section of the annular groove, in order to accurately limit the stator 31, a key block 25 used for limiting the stator 31 is fixed on the annular groove, as a preferred embodiment of the utility model, the first circulating oil path comprises two pairs of oil through holes which are arranged on the inner wall of the annular shell and are positioned at two sides of the stator 31, the oil return and the oil inlet of the oil through the communication control of the oil path, so that the rotor 32 rotates in the rotating oil cavity and in the reciprocating way at two sides of the stator 31 under the extrusion of oil, when the rotor 32 contacts the stator 31, the rotor 32 stops rotating, the stator 31 is utilized to limit the rotor 32, preferably, each pair of oil through holes comprises a main oil through hole and an auxiliary oil through hole, the auxiliary oil through hole is positioned between the main oil through hole and the stator 31 and close to the stator 31, and the distance between the main oil through hole and the auxiliary oil through hole, the oil return device is used for plugging the main oil through holes when the rotor 32 is close to the stator 31, the aperture of the auxiliary oil through holes is smaller than that of the main oil through holes, the oil return is only carried out through the auxiliary oil through holes when the rotor 32 is close to the stator 31 so as to slow down the oil return speed, the rotating speed of the rotor 32 when the rotor 32 is close to the stator 31 is further reduced, and the stator 31 is prevented from being damaged due to overlarge impact force of the rotor 32. In order to ensure that the rotor 32 contacts the stator 31 in place, preferably, both ends of the rotor 32 close to one side of the annular shell are respectively provided with a notch, when the rotor 32 contacts the stator 31, the auxiliary oil through holes are positioned in the notches, and the situation that the rotor 32 and the stator 31 cannot be matched in place because the auxiliary oil through holes are blocked when the rotor 32 does not contact the stator 31 is avoided.

As shown in fig. 3, in order to ensure that the oil return rate is sufficiently reduced during oil return without affecting the oil inlet rate, as a preferred embodiment of the present invention, two buffer blocks 28 corresponding to the respective auxiliary oil through holes are provided on the annular housing, the first circulation oil path includes circulation branches respectively provided in the buffer blocks 28 and respectively communicated with the auxiliary oil through holes, the circulation branches include an oil inlet branch and an oil return branch, a steel ball 30, a first compression spring 29 and a block 27 are sequentially provided in the oil inlet branch along the oil inlet direction, the steel ball 30 is blocked at the oil inlet end of the oil inlet branch by the first compression spring 29 for forming a check valve effect, the block 27 is detachably connected to the buffer blocks 28 and blocked at the end of the oil inlet branch, a buffer screw 26 is provided in the oil return branch, when the rotor 32 rotates through the main oil through hole, the oil return can only pass through the auxiliary oil through holes, the oil inlet branch is blocked by the check valve, the slow speed function can be realized only by returning oil through the clearance between the buffer screw 26 and the buffer block 28, the function of the other side is the same, when the oil inlet branch enters the rotating oil cavity, the steel ball 30 extrudes the first compression spring 29 to enable the oil inlet branch to be conducted, and the oil inlet speed is ensured.

As shown in fig. 1-3, a tool changing mechanism is provided, a telescopic oil chamber with a through structure is formed in a tool changing cylinder 18, a piston rod 19 penetrates through the telescopic oil chamber, one end of the piston rod 19 extends out of the tool changing cylinder 18 and is connected with a tool arm, a second circulating oil path communicated with the telescopic oil chamber is formed in a side wall of the tool changing cylinder 18, the telescopic oil chamber drives the piston rod 19 to axially extend and retract through the second circulating oil path, the piston rod 19 drives the tool arm to realize the functions of tool removing and tool inserting, a cylinder rear cover 8, a transition shaft 23 and a cylinder front cover 20 are preferably fixed in the telescopic oil chamber along the extending direction of the piston rod 19, the cylinder front cover 20 is provided with a first through hole for the piston rod 19 to penetrate through, a sliding seal is formed between the piston rod 19 and the first through hole, for example, a sealing ring and the like are sleeved on the inner wall of the first through, the piston is positioned between the transition shaft 23 and the oil cylinder front cover 20, and a sliding seal is formed between the outer wall of the piston and the inner wall of the telescopic oil cavity, so that the piston rod 19 is effectively pushed when oil is fed and returned in the telescopic oil cavity.

As shown in fig. 1, in order to ensure that the tool changing cylinder 18 rotates accurately in place, a plurality of limiting blocks 4 are fixed on the annular shell, limiting bolts 3 and inductive switches 5 are arranged on the limiting blocks 4, and a rotary collision block 6 matched with the limiting blocks 4 is fixed on the tool changing cylinder 18, for example, the limiting blocks 4 are in an L-shaped structure, one side of each limiting block is provided with the inductive switch 5, the other side of each limiting block is provided with the limiting bolt 3, the limiting bolt 3 can move back and forth along a direction perpendicular to one side of the limiting block 4 to adjust a stop position when the rotary collision block 6 contacts with the limiting bolt 3, when the tool changing cylinder 18 drives the rotary collision block 6 to rotate until the rotary collision block contacts with the limiting bolt 3, the rotary collision.

In order to ensure accurate positioning of the slotting tool and the pulling tool, as shown in fig. 1 and fig. 2, a telescopic rod 12 is arranged in a tool changing oil cylinder 18, second through holes for the telescopic rod 12 to penetrate through are formed in the centers of an oil cylinder rear cover 8 and a transition shaft 23, a bar-shaped groove adapted to the telescopic rod 12 is formed in one end, close to the transition shaft 23, of a piston rod 19, the telescopic rod 12 comprises a telescopic section and a rear cover 15 section which respectively extend out of the transition shaft 23 and the oil cylinder rear cover 8, the telescopic section penetrates through and is limited in the bar-shaped groove, a signal ring 11 is installed on the rear cover 15 section, a pulling tool induction switch 13 matched with the signal ring 11 is arranged on the oil cylinder rear cover 8, a slotting tool induction switch 1 matched with the signal switch is arranged on an annular shell, a switch frame 2 is preferably arranged on a front cover 17, and; for guaranteeing the return of signal ring 11, preferably, the tip of flexible section radially extends and has annular bulge, the open end of bar groove is equipped with and is used for spacing bellied flexible dog 21 of annular, the part that is located the second through-hole on the telescopic link 12 has cup jointed second compression spring 22 and spring collar 24, spring collar 24 is fixed on the outer wall of telescopic link 12, and one side that the second through-hole is close to piston rod 19 is equipped with the spacing portion that is used for joint second compression spring 22, second compression spring 22 is located and is used for promoting telescopic link 12 to reset between spring dog and the spacing portion.

Furthermore, in order to install the signal ring 11 and the tool-pulling inductive switch 13 conveniently, the outer edge of the oil cylinder rear cover 158 is detachably connected to one end of the annular shell, the oil cylinder rear cover 8 extends towards the side of the tool-changing oil cylinder 18 to form a flange matched with the telescopic oil cavity, the flange penetrates through the telescopic oil cavity, and forms sliding seal with the inner wall of the telescopic oil cavity, the structure ensures that the oil cylinder rear cover 8 can be fixed on the annular shell and can form seal for the telescopic oil cavity, meanwhile, when the telescopic oil cylinder rotates, the rotation of the telescopic oil cylinder cannot be limited, meanwhile, a signal ring installation groove 9 is arranged on the side wall of the oil cylinder rear cover 8, a hole for the telescopic rod 12 to penetrate through is arranged on the signal ring installation groove 9, a knife pulling inductive switch 13 is fixed on the side wall of the signal exchange installation cavity, the part of the telescopic rod 12, which is provided with the signal ring 11, is positioned in the signal ring installation groove 9, and a slot cover 10 for closing the signal ring mounting slot 9 is fixed on the wall of the signal ring mounting slot 9.

The adaptability that carries out according to actual demand all is in the protection scope of the utility model. The utility model discloses a concrete example is applied to explain the principle and the implementation mode of the utility model, and the explanation of the above example is only used to help understand the method and the core idea of the utility model; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the concrete implementation and the application scope. In summary, the content of the present specification should not be construed as a limitation of the present invention.

Claims

1. A rotating mechanism of a tool changing oil cylinder is characterized by comprising an annular shell and a first circulating oil path, wherein the annular shell is annularly sleeved on the outer wall of the tool changing oil cylinder;

a rotary oil cavity in an annular groove-shaped structure is formed in the inner wall of the annular shell, rotary sealing mechanisms are arranged at two ends of the annular groove, the annular shell is fixed on the outer wall of the tool changing oil cylinder through each rotary sealing mechanism, a rotor matched with the section of the annular groove is arranged on the part, corresponding to the annular groove, of the outer wall of the tool changing oil cylinder, the first circulating oil path is communicated with the annular groove, the rotor is driven to rotate in the annular groove by oil fed into the annular groove, and the rotor drives the tool changing oil cylinder to integrally rotate;

2. The rotating mechanism of the tool changing cylinder as claimed in claim 1, wherein the first circulating oil path includes two pairs of oil passing holes opened on the inner wall of the annular housing and located at both sides of the stator, each pair of oil passing holes includes a main oil passing hole and an auxiliary oil passing hole, the auxiliary oil passing hole is located between the main oil passing hole and the stator and close to the stator, and the main oil passing hole and the auxiliary oil passing hole have a circumferential distance less than the length of the rotor, and the aperture of the auxiliary oil passing hole is less than the main oil passing hole, so that oil returns through the auxiliary oil passing hole only when the rotor is close to the stator to slow down the oil return rate.

3. The rotating mechanism of the tool changing cylinder as claimed in claim 2, wherein notches are respectively formed at two ends of one side of the rotor, which is close to the annular housing, and when the rotor is in contact with the stator, the auxiliary oil through hole is located in the notches.

4. The rotating mechanism of the tool changing cylinder as claimed in claim 2 or 3, wherein two buffer blocks corresponding to the auxiliary oil through holes are arranged on the annular shell, the first circulating oil path comprises circulating branches which are respectively arranged in the buffer blocks and respectively communicated with the auxiliary oil through holes, each circulating branch comprises an oil inlet branch and an oil return branch, steel balls, first compression springs and a blocking block are sequentially arranged in the oil inlet branch along an oil inlet direction, the steel balls are blocked at the oil inlet end of the oil inlet branch through the first compression springs to form a check valve effect, the blocking block is detachably connected to the buffer blocks and blocked at the end parts of the oil inlet branch, and buffer screws are arranged in the oil return branches.

5. The tool changing mechanism of the rotating mechanism of the tool changing oil cylinder is characterized in that a telescopic oil cavity with a through structure is formed in the tool changing oil cylinder, a piston rod penetrates through the telescopic oil cavity, one end of the piston rod extends out of the tool changing oil cylinder and is connected with a tool arm, a second circulating oil path communicated with the telescopic oil cavity is formed in the side wall of the tool changing oil cylinder, the telescopic oil cavity drives the piston rod to stretch and retract along the axial direction through the oil inlet of the second circulating oil path, and the piston rod drives the tool arm to realize the functions of tool pulling and tool inserting.

6. The tool changing mechanism according to claim 5, wherein a plurality of limiting blocks are fixed on the annular shell, limiting bolts and inductive switches are arranged on the limiting blocks, a rotary collision block matched with the limiting blocks is fixed on the tool changing oil cylinder, the tool changing oil cylinder drives the rotary collision block to rotate until the rotary collision block is contacted with the limiting bolts and then stops, and the inductive switches output signals of rotating in place.

7. The tool changing mechanism according to claim 6, wherein an oil cylinder rear cover, a transition shaft and an oil cylinder front cover are fixed in the telescopic oil cavity along the extending direction of the piston rod, the oil cylinder front cover is provided with a first through hole for the piston rod to penetrate through, a sliding seal is formed between the piston rod and the first through hole, a piston is connected to the part of the piston rod located in the tool changing oil cylinder, the piston is located between the transition shaft and the oil cylinder front cover, and a sliding seal is formed between the outer wall of the piston and the inner wall of the telescopic oil cavity.

8. The tool changing mechanism according to claim 7, wherein the outer edge of the oil cylinder rear cover is detachably connected to one end of the annular housing, a flange matched with the telescopic oil cavity extends towards the tool changing oil cylinder side of the oil cylinder rear cover, and the flange penetrates through the telescopic oil cavity and forms sliding seal with the inner wall of the telescopic oil cavity.

9. The tool changing mechanism according to claim 8, wherein a telescopic rod is arranged in the tool changing oil cylinder, a second through hole for the telescopic rod to penetrate is formed in the center of the oil cylinder rear cover and the center of the transition shaft, a bar-shaped groove matched with the telescopic rod is formed in one end, close to the transition shaft, of the piston rod, the telescopic rod comprises a telescopic section and a rear cover section which extend out of the transition shaft and the oil cylinder rear cover respectively, the telescopic section penetrates through and is limited in the bar-shaped groove, a signal ring is installed on the rear cover section, a tool pulling inductive switch matched with the signal ring is arranged on the oil cylinder rear cover, and a tool inserting inductive switch matched with the signal ring is arranged on the annular shell.

10. The tool changing mechanism according to claim 9, wherein an annular protrusion extends radially from an end of the telescopic section, an opening end of the strip-shaped groove is provided with a telescopic stop for limiting the annular protrusion, a second compression spring and a spring retainer ring are sleeved on a part, located in the second through hole, of the telescopic rod, the spring retainer ring is fixed on an outer wall of the telescopic rod, a limiting portion for clamping the second compression spring is arranged on one side, close to the piston rod, of the second through hole, and the second compression spring is located between the spring stop and the limiting portion and used for pushing the telescopic rod to reset.