CN216030052U

CN216030052U - Small-size annular iron core centering cutting air gap device

Info

Publication number: CN216030052U
Application number: CN202122114948.8U
Authority: CN
Inventors: 张希望
Original assignee: Nicore Electrical Manufactory Co ltd
Current assignee: Nicore Electrical Manufactory Co ltd
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2022-03-15
Anticipated expiration: 2031-09-03

Abstract

The utility model provides a small-size annular iron core centering cutting air gap device, including linear guide motion, abrasive cutoff piece, cutting clamp and elastic positioning cutting die assembly, elastic positioning cutting die assembly includes elastic positioning cutting die and embolias N small-size annular iron core on it, the top is equipped with square cutting groove on the elastic positioning cutting die, the left and right sides is equipped with the location tip respectively, be equipped with N equidistant vertical screw on cutting groove bottom surface central line, position adjustable threaded connection is made with N screw respectively to N elastic positioning spare, and its elasticity front end exposes outside the bottom plane. The elastic positioning cutting die assembly is placed between the 1 st baffle and the 2 nd baffle of the cutting clamp and is respectively matched, positioned, contacted and connected with the 1 st positioning groove and the 2 nd positioning groove through the left positioning end part and the right positioning end part. The device carries out three-point elastic centering positioning on the inner ring of the small annular iron core with the cut air gap by adopting the elastic positioning cutting die, and all the small annular iron cores with the cut air gap are qualified products.

Description

Small-size annular iron core centering cutting air gap device

Technical Field

The utility model relates to the technical field of small-sized rolled iron core manufacturing, in particular to a device for centering and cutting an air gap of a small-sized annular iron core.

Background

The small annular iron core with the air gap is widely applied to electric elements such as reactors, current transformers, sensors, high-frequency transformers and the like of electric control systems, communication systems and electric power monitoring systems. The cutting of the air gap in the small toroidal core is an intermediate process step in the manufacturing process of the electrical component, and in the next assembly process step, the small toroidal core and the air gap thereof need to be installed in the insulating sheath, and the toroidal core and the air gap thereof need to be connected with the insulating sheath in a matching and nesting manner. The insulating sheath is designed and manufactured according to the annular iron core and the contour dimension of the centering cutting air gap of the annular iron core, and the insulating sheath is formed by molding plastic powder through the mold. Therefore, the insulating sheath with uniform specification has a strict requirement on the centering degree of the annular iron core to the air gap to be cut, and the centering degree is represented by the vertical distance F from the center O of the annular iron core 1 to the center line MM' of the air gap to be actually cut. The dimensional ranges of the small toroidal cores referred to herein are: the outer diameter D = phi 20-65 mm, the inner diameter D = phi 12-40 mm, the height is 5-30 mm, and the width range of the cut air gap is 1.2-8 mm. The insulating sheath used in the subsequent process requires that the centering degree F = 0.3-0.4 mm of the cutting air gap in centering of the corresponding annular iron core, as shown in FIG. 1, the PP 'line shown in FIG. 1 is the center line of the nominal air gap of the annular iron core 1, and the center line PP' passes through the center O of the annular iron core 1.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem of providing a small annular iron core centering cutting air gap device, which can simultaneously perform centering cutting air gaps on a plurality of small annular iron cores with the same specification, and ensure that the centering degree of the centering cutting air gaps is equal to or less than 0.15mm, thereby completely meeting the requirement of post-process on the centering cutting air gaps of the small annular iron cores.

The technical solution proposed by the present invention is as follows: a small-sized annular iron core centering cutting air gap device comprises a grinding wheel cutting blade and a grinding wheel cutting machine thereof, and is also provided with a linear guide rail motion mechanism, a cutting clamp and an elastic positioning cutting die; the elastic positioning cutting die is cylindrical, an axial cutting groove is formed in the top of the elastic positioning cutting die, positioning end portions are respectively arranged on the left side and the right side of the elastic positioning cutting die, positioning surfaces which are parallel to each other are respectively arranged on the front side and the rear side of each positioning end portion, a side plane is arranged on the front side or the rear side of each positioning end portion, a bottom plane is arranged at the bottom of each positioning end portion, N equidistant and vertical screw holes are formed in the bottom surface of each cutting groove and located on the center line of the cutting groove, the screw holes are in threaded connection with a threaded cylinder of the elastic positioning piece, and the elastic front end portion of the elastic positioning piece is located on the outer side of the bottom plane, wherein N = 6-12; arranging N annular iron cores on the elastic positioning cutting die in a sleeving manner to form an elastic positioning cutting die assembly; placing an elastic positioning cutting die assembly between a 1 st baffle and a 2 nd baffle of the cutting clamp, wherein the positioning end parts of the left side and the right side of the elastic positioning cutting die are respectively matched, positioned and connected with a 1 st positioning groove of the 1 st baffle and a 2 nd positioning groove of the 2 nd baffle, and the 1 st baffle and the 2 nd baffle tightly press the N annular iron cores through a screw rod, a nut, a guide rod, a linear bearing and a pressing block of the cutting clamp; the cutting clamp is connected with the two linear guide rails of the linear guide rail motion mechanism in a matching and sliding manner through the base, and the linear guide rail motion mechanism arranged on the base drives the cutting clamp to do linear reciprocating motion through a servo motor, a ball screw pair and the two linear guide rails which are controlled by a program controller; the abrasive wheel cutting piece is arranged right in front of and above the linear guide rail movement mechanism, and the central plane of the abrasive wheel cutting piece, the central line of the cutting groove, the central line of the elastic positioning piece, the central line of the positioning end part, the central line of the 1 st positioning groove and the central line of the 2 nd positioning groove are all located on the same vertical plane.

The elastic positioning piece comprises a threaded cylinder, a spring and a steel ball, the spring is arranged in the threaded cylinder, a large hemisphere of the steel ball is positioned on the inner side of an opening part of the threaded cylinder and is in movable contact connection with the opening part in a matched mode, and the steel ball is in elastic contact connection with one end of the spring.

The maximum telescopic quantity of the steel balls in the elastic positioning piece is about 1.0mm, and the effective use telescopic quantity is 0.2-0.8 mm.

The groove sides on two sides of the cutting groove in the elastic positioning cutting die assembly are in linear contact with the inner circles of the N annular iron cores to form A, B two supporting positioning points, the steel balls of the N elastic positioning pieces are in contact with the elastic points at the bottommost parts of the corresponding N annular iron cores respectively to form elastic positioning points C, A, B, C three-point positioning contact connection is formed between each annular iron core inner circle and the corresponding cutting groove side and the corresponding steel balls, and the triangle delta ABC is an isosceles triangle.

The cutting clamp comprises a frame, a pressing block, a screw, a nut, linear bearings and guide rods, wherein a 1 st baffle and a 2 nd baffle are arranged between a front plate of the frame and the pressing plate, a 1 st positioning groove is formed in the center of the upper portion of the 1 st baffle, the bottom of the 1 st baffle is matched with a 3 rd positioning groove in the center of the bottom of the frame in a positioning sliding manner, a 2 nd positioning groove is formed in the center of the upper portion of the 2 nd baffle, the bottom of the 2 nd baffle is matched with a 3 rd positioning groove in a positioning sliding manner, and the two linear bearings are arranged on the pressing block and drive the 2 nd baffle to reciprocate through the screw, the nut and the two guide rods.

Compared with the prior art, the utility model has the following beneficial effects:

the utility model relates to a device for centering and cutting air gaps of a small annular iron core, which supports and centers a row of a plurality of small annular iron cores which simultaneously center and cut air gaps by adopting a cylindrical elastic positioning cutting die, if the annular iron core is supported only by two points of the slot edges A, B at two sides of a cutting slot, a larger gap exists between the inner ring of the annular iron core and the outer diameter of the cutting die due to factors such as larger tolerance and the like of the inner ring of the annular iron core, the annular iron core is in a suspension state at the moment and can freely swing around A, B two points before being clamped, the position of each annular iron core is different during the process of putting the row of annular iron cores into a cutting clamp and clamping, a part of the inner ring of the annular iron core deviates from the outer ring of the cutting die more, and the cut air gaps become unqualified products. The elastic positioning cutting die of the device is characterized in that N vertical adjustable elastic positioning pieces with equal intervals are arranged on the central line of the bottom surface of a cutting groove and are in elastic contact connection with the bottommost corresponding positioning of the inner rings of N annular iron cores, and at the moment, even if the annular iron cores swing around two points of the cutting groove edge A, B, the annular iron cores can be positioned back to the center by the steel balls of the elastic positioning pieces, because the steel balls have certain elasticity and can roll freely. At the moment, the circle center of the annular iron core, the circle center of the elastic positioning cutting die and the central line of the elastic positioning piece are all located on the vertical central line of the elastic positioning cutting die, the central line of the air gap formed by cutting the annular iron core coincides with the vertical central line of the elastic positioning cutting die, and namely the centering degree of the air gap of the annular iron core is zero. Products obtained by cutting the air gap of the annular iron core by adopting the device are all qualified products.

Because this device simple structure, simple operation can cut 6 ~ 12 annular iron core air gaps with the specification moreover once, so production efficiency is high.

Drawings

Fig. 1 is a front view of a small toroidal core with a centered cutting air gap.

Fig. 2 is a schematic structural diagram of a device for cutting an air gap in centering of a small toroidal core according to the present invention.

Fig. 3 is a schematic view of the cutting jaw of fig. 2.

Fig. 4 is a schematic view of an assembly structure of the grinding wheel cutting blade, the elastic positioning cutting die assembly and the cutting clamp shown in fig. 2.

Fig. 5 is a schematic structural view of the elastic positioning cutting die obtained by removing N annular iron cores from the elastic positioning cutting die assembly shown in fig. 2.

Fig. 6 is a schematic view of another view of the elastically positioned cutting die of fig. 5.

Fig. 7 is a schematic front view of the spring-loaded cutting die assembly of fig. 4.

Fig. 8 is a schematic structural view of the elastic positioning member shown in fig. 6.

The notation in the figure is: 1. an annular iron core; 2. elastically positioning the cutting die; 2-1, positioning the end part; 2-1-1, a positioning surface; 2-2. side plane; 2-3, an elastic positioning piece; 2-3-1. a threaded cylinder; 2-3-2. a spring; 2-3-3. steel balls; 2-4, bottom plane; 2-5, cutting the groove; 2-6, screw holes; 3. cutting the clamp; 3-1, pressing blocks; 3-2. screw; 3-3, a nut; 3-4, linear bearing; 3-5, a guide rod; 3-6. frame; 3-6-1, the 3 rd positioning groove; 3-7, baffle 1; 3-7-1, the 1 st positioning groove; 3-8, baffle 2; 3-8-1, 2 nd positioning groove; 4. cutting the slices; 5. a base; 6. a linear guide rail; 7. a ball screw pair; 8. a servo motor; 9. a machine base; 21. the cutting die assembly is elastically positioned.

Detailed Description

The utility model is illustrated in further detail by the following examples.

Referring to fig. 1 to 8, the device for centering and cutting an air gap in a small annular iron core comprises a grinding wheel cutting blade 4 and a grinding wheel cutting machine thereof, and is further provided with a linear guide rail movement mechanism, a cutting clamp 3 and an elastic positioning cutting die 2; the elastic positioning cutting die 2 is cylindrical, an axial cutting groove 2-5 is formed in the top of the elastic positioning cutting die, positioning end parts 2-1 are respectively arranged on the left side and the right side of the elastic positioning cutting die, positioning surfaces 2-1-1 which are parallel to each other are respectively arranged on the front side and the rear side of each positioning end part 2-1, a side plane 2-2 is arranged on the front side or the rear side of each positioning end part 2-1, a bottom plane 2-4 is arranged at the bottom of each positioning end part 2-5, N equidistant and vertical screw holes 2-6 are formed in the center line of each cutting groove 2-5, each screw hole 2-6 is in threaded connection with a threaded cylinder 2-3-1 of the elastic positioning part 2-3, the elastic front end part of the elastic positioning part 2-3 is located on the outer side of the bottom plane 2-4, and N = 6-12; arranging N annular iron cores 1 on the elastic positioning cutting die 2 in a sleeving manner to form an elastic positioning cutting die assembly 21; placing an elastic positioning cutting die assembly 21 between a 1 st baffle 3-7 and a 2 nd baffle 3-8 of the cutting clamp 3, wherein positioning end parts 2-1 at the left side and the right side of the elastic positioning cutting die 2 are respectively matched, positioned and connected with a 1 st positioning groove 3-7-1 of the 1 st baffle 3-7 and a 2 nd positioning groove 3-8-1 of the 2 nd baffle 3-8, and the 1 st baffle 3-7 and the 2 nd baffle 3-8 tightly press the N annular iron cores 1 through a screw rod 3-2, a nut 3-3, a guide rod 3-5, a linear bearing 3-4 and a pressing block 3-1 of the cutting clamp 3; the cutting clamp 3 is connected with two linear guide rails 6 of the linear guide rail motion mechanism in a matching and sliding manner through a base 5, and the linear guide rail motion mechanism arranged on a machine base 9 drives the cutting clamp 3 to do linear reciprocating motion through a servo motor 8, a ball screw pair 7 and the two linear guide rails 6 controlled by a program controller; the abrasive wheel cutting piece 4 is arranged right in front of and above the linear guide rail movement mechanism, and the central plane of the abrasive wheel cutting piece 4, the central line of the cutting groove 2-5, the central line of the elastic positioning piece 2-3, the central line of the positioning end part 2-1, the central line of the 1 st positioning groove 3-7-1 and the central line of the 2 nd positioning groove 3-8-1 are all located on the same vertical plane.

The elastic positioning piece 2-3 consists of a threaded cylinder 2-3-1, a spring 2-3-2 and a steel ball 2-3-3, the spring 2-3-2 is arranged in the threaded cylinder 2-3-1, a large hemisphere of the steel ball 2-3-3 is positioned at the inner side of an opening part of the threaded cylinder 2-3-1 and is matched and movably connected with the opening part in a contact manner, and the steel ball 2-3-3 is elastically connected with one end of the spring 2-3-2 in a contact manner.

The maximum expansion amount of the steel balls 2-3-3 in the elastic positioning piece 2-3 is about 1.0mm, and the effective using expansion amount is 0.2-0.8 mm.

The two sides of the cutting groove 2-5 in the elastic positioning cutting die assembly 21 are in line contact with the upper parts of the inner rings of the N annular iron cores 1 to form A, B two supporting positioning points, the steel balls 2-3-3 of the N elastic positioning pieces 2-3 are respectively in point contact with the elastic points at the bottommost of the inner rings of the N annular iron cores 1 to form elastic positioning points C, the inner ring of each annular iron core 1 is in positioning contact connection with A, B, C three points formed between the corresponding cutting groove 2-5 and the steel balls 2-3-3, and triangle delta ABC is an isosceles triangle.

The cutting clamp 3 consists of a frame 3-6, a compaction block 3-1, a screw rod 3-2, a nut 3-3, a linear bearing 3-4 and a guide rod 3-5, a 1 st baffle 3-7 and a 2 nd baffle 3-8 are arranged between a front plate of the frame 3-6 and the compaction plate 3-1, a 1 st positioning groove 3-7-1 is arranged in the center of the upper part of the 1 st baffle 3-7, the bottom of the 1 st baffle is in matching positioning sliding connection with the 3 rd positioning groove 3-6-1 positioned in the center of the bottom of the frame 3-6, a 2 nd positioning groove 3-8-1 is arranged in the center of the upper part of the 2 nd baffle 3-8, the bottom of the 2 nd baffle is in matching positioning sliding connection with the 3 rd positioning groove 3-6-1, and the compaction block 3-1 provided with the two linear bearings 3-4 is connected with the screw rod 3-2, the nut 3-3, The two guide rods 3-5 drive the second baffle 3-8 to do reciprocating linear motion.

The structural principle and the working process of the device for centering and cutting the air gap by the small annular iron core are as follows:

the device is used for cutting an air gap in the centering of the small annular iron core 1 to meet the requirement of the electrical performance of the small annular iron core, and in addition, the position size precision of the air gap, namely the vertical distance F between the actually cut air gap center line MM' and the circle center O of the annular iron core 1 also puts forward a strict requirement, wherein F is the centering degree of the actually cut air gap. The subsequent process is an assembly process of the annular iron core with the air gap and the insulating sheath, and in order to meet the requirement of assembly precision, the requirement of air gap alignment of the small annular iron core 1 with the limited size range does not exceed the range of 0.3-0.4 mm, namely F is less than or equal to 0.3-0.4 mm.

In order to solve the problems of supporting and centering the cutting air gap of the annular iron core, a cylindrical cutting die can be adopted, a square cutting groove is formed in the center of the upper portion of the cutting die, square positioning end portions are respectively arranged on the left side and the right side of the cutting die, a plurality of annular iron cores with the same specification are sleeved and arranged on the cutting die, then the cutting die is positioned on a clamp by a cutting clamp, and the annular iron cores are clamped tightly, so that the air gap cutting can be carried out. At this time, some of the cut air gaps exceed the requirement of centering accuracy, and the following reasons are considered: the tolerance range of the inner diameter d of the small annular iron core is +/-0.3-0.4 mm, in order to enable the annular iron core to be smoothly sleeved on a cutting die, the outer diameter of the cutting die is 0.2mm smaller than the minimum inner diameter of the annular iron core, namely the maximum gap between the inner ring of the annular iron core and the outer diameter of the cutting die is 2 x (0.3-0.4) +0.2= 0.8-1.0 mm; secondly, the annular iron core is supported at the top of the cutting die, and the groove edges at two sides of the cutting groove are supporting points, so that the maximum gap between the outer diameter of the cutting die and the inner ring of the annular iron core is generated at two sides of the lower part of the annular iron core, which is equivalent to the swinging of the inner ring of the annular iron core around the two supporting points at the groove edges, the maximum swinging amplitude is at the lower part, and the center of the annular iron core is maximally deviated from the center of the cutting die by 0.4-0.5 mm at the moment according to half conversion, namely the centering degree of an air gap of the annular iron core is 0.4-0.5 mm; and thirdly, after a row of annular iron cores with the same specification are sleeved with the cutting die, the cutting die is conveyed to a clamp to position and clamp the row of annular iron cores, before clamping, the row of annular iron cores are in a movable suspension state, the annular iron cores can freely swing around a groove edge fulcrum and are in a random state, so that when the row of annular iron cores are clamped, a part of the annular iron cores are in a large maximum swing range, and the centering degree of the cut air gap is partially larger than 0.3-0.4 mm. Based on the three main reasons, the cutting die of the device is provided with N equidistant vertical screw holes 2-6 at the central line position of the bottom of the cutting groove 2-5, each screw hole 2-6 is in threaded connection with an elastic positioning piece 2-3, and the elastic front end part of the elastic positioning piece 2-3, namely a part of the steel ball 2-3-3, extends out of the bottom plane 2-4 to form the elastic positioning cutting die 2. The center line of each elastic positioning piece 2-3 intersects with the center line of the elastic positioning cutting die 2 at the circle center O. After the N annular iron cores 1 are sleeved in the elastic positioning cutting die 2, the steel balls 2-3-3 of the N elastic positioning pieces 2-3 respectively elastically support the bottommost part of the inner ring of the corresponding annular iron core 1, at the moment, the upper part of the inner ring of the annular iron core 1 is in contact connection with the two groove sides of the cutting groove 2-5 to form A, B two-point bearing positioning points, the bottommost part of the inner ring of the annular iron core 1 is in contact connection with the steel ball 2-3-3 to form a supporting positioning point C, the annular iron core 1 cannot swing around A, B two points, moreover, the triangle ABC is an isosceles triangle, the central line of the annular iron core 1 and the central line of the elastic positioning cutting die 2 are respectively intersected with the central line of the triangle ABC at the point O and the point O', thus, the central line of the air gap cut by the annular iron core is ensured to be coincident with the central line of the delta ABC in the state, the alignment of the air gap F =0, and this state can be maintained until the row of annular cores 1 is clamped and fixed by the cutting jaw 3. Considering that factors such as part manufacturing tolerance, assembly error and the like can generate a centering error of 0.05-0.1 mm, the centering degree F of the cutting air gap in centering of the small annular iron core in the specification range is less than or equal to 0.15mm by adopting the device. In addition, a side plane 2-2 is arranged on the elastic positioning cutting die 2, so that a space is reserved for containing a sheet head left after the annular iron core is wound.

When the small-sized annular iron core cutting machine works, a small-sized annular iron core 1 needing to be centered and cut an air gap is sleeved into the elastic positioning cutting die 2, then the small-sized annular iron core 1 is placed between the 1 st baffle 3-7 and the 2 nd baffle 3-8 of the cutting clamp 3, meanwhile, the positioning end parts 2-1 on the left side and the right side of the elastic positioning cutting die 2 are respectively in positioning contact connection with the 1 st positioning groove 3-7-1 and the 2 nd positioning groove 3-8-1 through the positioning surfaces 2-1-1 of the elastic positioning cutting die, the screw rod 3-2 is rotated, and the 2 nd baffle 3-8 is driven by the nut 3-3, the two guide rods 3-5, the linear bearing 3-4 and the pressing block 3-1 to clamp a row of small-sized annular iron cores 1. A grinding wheel cutting piece 4 of the grinding wheel cutting machine is arranged at a position right above the front of the cutting clamp 3, and the central plane of the grinding wheel cutting piece 4, the central line of the 1 st positioning groove 3-7-1, the central line of the 2 nd positioning groove 3-8-1 and the central line of the cutting groove 2-5 are all located on the same vertical plane. The cutting clamp 3 is fixed on the base 5, the base 5 is connected with the two linear guide rails 6 in a sliding mode in a matching mode, the two linear guide rails 6, the servo motor 8 and the ball screw pair 7 arranged between the output shaft of the servo motor 8 and the base 5 are arranged on the base 9, the servo motor 8 controlled by the program controller drives the base 5 to do reciprocating linear motion back and forth through the ball screw pair 7 and the two linear guide rails 6, and therefore the grinding wheel cutting piece 4 can conduct centering cutting air gaps on the row of small annular iron cores 1. The air gap pair degree F is less than or equal to 0.15 mm.

Claims

1. The utility model provides a small-size annular iron core centering cutting air gap device, includes abrasive wheel cutting piece (4) and abrasive wheel cutting machine thereof, its characterized in that: the cutting machine is also provided with a linear guide rail movement mechanism, a cutting clamp (3) and an elastic positioning cutting die (2); the elastic positioning cutting die (2) is cylindrical, an axial cutting groove (2-5) is formed in the upper top of the elastic positioning cutting die, positioning end parts (2-1) are arranged on the left side and the right side of the elastic positioning cutting die respectively, positioning faces (2-1-1) which are parallel to each other are arranged on the front side and the rear side of each positioning end part (2-1) respectively, a side plane (2-2) is arranged on the front side or the rear side of each positioning end part (2-1), a bottom plane (2-4) is arranged at the bottom of each positioning end part (2-5), N equidistant and vertical screw holes (2-6) are formed in the center line of each cutting groove (2-5), the screw holes (2-6) are in threaded connection with a threaded cylinder (2-3-1) of the elastic positioning part (2-3), the elastic front end part of the elastic positioning part (2-3) is positioned outside the bottom plane (2-4), wherein N = 6-12; arranging N annular iron cores (1) on the elastic positioning cutting die (2) in a sleeved mode to form an elastic positioning cutting die assembly (21); placing an elastic positioning cutting die assembly (21) between a 1 st baffle (3-7) and a 2 nd baffle (3-8) of the cutting clamp (3), matching and positioning the positioning end parts (2-1) at the left side and the right side of the elastic positioning cutting die (2) with a 1 st positioning groove (3-7-1) of the 1 st baffle (3-7) and a 2 nd positioning groove (3-8-1) of the 2 nd baffle (3-8) respectively, and compressing N annular iron cores (1) through a screw rod (3-2), a nut (3-3), a guide rod (3-5), a linear bearing (3-4) and a compression block (3-1) of the cutting clamp (3); the cutting clamp (3) is connected with the two linear guide rails (6) of the linear guide rail movement mechanism in a matching and sliding manner through the base (5), and the linear guide rail movement mechanism arranged on the base (9) drives the cutting clamp (3) to do linear reciprocating motion through the servo motor (8), the ball screw pair (7) and the two linear guide rails (6) controlled by the program controller; the abrasive wheel cutting piece (4) is arranged right in front of and above the linear guide rail movement mechanism, and the central plane of the abrasive wheel cutting piece (4), the central line of the cutting groove (2-5), the central line of the elastic positioning piece (2-3), the central line of the positioning end part (2-1), the central line of the 1 st positioning groove (3-7-1) and the central line of the 2 nd positioning groove (3-8-1) are all located on the same vertical plane.

2. The small toroidal core centering air gap cutting device according to claim 1, wherein: the elastic positioning piece (2-3) consists of a threaded cylinder (2-3-1), a spring (2-3-2) and a steel ball (2-3-3), the spring (2-3-2) is arranged in the threaded cylinder (2-3-1), a large hemisphere of the steel ball (2-3-3) is positioned on the inner side of an opening part of the threaded cylinder (2-3-1) and is in movable contact connection with the opening part in a matching mode, and the steel ball (2-3-3) is in elastic contact connection with one end of the spring (2-3-2).

3. The small toroidal core centering air gap cutting device according to claim 1, wherein: the maximum expansion amount of the steel balls (2-3-3) in the elastic positioning pieces (2-3) is about 1.0mm, and the effective expansion amount is 0.2-0.8 mm.

4. The small toroidal core centering air gap cutting device according to claim 1, wherein: the two sides of the cutting groove (2-5) in the elastic positioning cutting die assembly (21) are in line contact with the upper parts of the inner rings of the N annular iron cores (1) to form A, B two supporting positioning points, steel balls (2-3-3) of the N elastic positioning pieces (2-3) are in contact with elastic points at the bottommost part of the corresponding inner rings of the N annular iron cores (1) respectively to form elastic positioning points C, A, B, C three-point positioning contact connection is formed between each inner ring of the annular iron core (1) and the corresponding groove side of the cutting groove (2-5) and the steel balls (2-3-3), and triangle delta ABC is an isosceles triangle.

5. The small toroidal core centering air gap cutting device according to claim 1, wherein: the cutting clamp (3) consists of a frame (3-6), a pressing block (3-1), a screw rod (3-2), a nut (3-3), a linear bearing (3-4) and a guide rod (3-5), a 1 st baffle (3-7) and a 2 nd baffle (3-8) are arranged between a front plate of the frame (3-6) and the pressing block (3-1), a 1 st positioning groove (3-7-1) is arranged in the center of the upper part of the 1 st baffle (3-7), the bottom of the cutting clamp is in matching positioning sliding connection with a 3 rd positioning groove (3-6-1) positioned in the center of the bottom of the frame (3-6), a 2 nd positioning groove (3-8-1) is arranged in the center of the upper part of the 2 nd baffle (3-8), and the bottom of the cutting clamp is in matching positioning sliding connection with the 3 rd positioning groove (3-6-1), the 2 nd baffle (3-8) is driven to do reciprocating linear motion through a screw rod (3-2), a nut (3-3), a pressing block (3-1) provided with two linear bearings (3-4) and two guide rods (3-5).