Connecting structure of a replaceable head reamer and a method of use

Abstract

The application discloses a connecting structure of a replaceable head reamer and a use method, and the connecting structure is characterized in that: a plurality of balls are arranged in the inner wall surface of a tool rod, and the balls are subjected to the force of the inner wall surface, so that the balls have a downward force and a centripetal force; the centripetal force realizes centering and positioning; in cooperation with the positioning of a contact surface, double positioning is realized; the downward force can lock the tool head and the tool rod, and the requirement of finish machining of a hole after the tool head and the tool rod are connected is met; threads are formed on the connecting sleeve according to the application, and the connecting sleeve can be made of the same steel material as the tool rod; the tool head only needs to be simply machined in the outer circle, so that the production cost of the reamer head is greatly reduced; in addition, in the replaceable head tool, the tool head is a consumable part, so that reducing the cost of the tool head becomes the key point, and the reduction of machining difficulty will greatly reduce the use cost of the user.

Description

Technical Field

[0001] This invention belongs to the field of reamer technology, and particularly relates to a connection structure and usage method of a replaceable head reamer. Background Technology

[0002] A reamer is a rotary cutting tool with one or more cutting teeth used to remove a thin layer of metal from the surface of a machined hole. Reamers are rotary finishing tools with straight or spiral cutting edges, used for enlarging or repairing holes. Because of the small cutting volume, the machining accuracy requirements of reamers are usually higher than those of drill bits. They can be operated manually or mounted on a drilling machine.

[0003] A reamer consists of a cutting head and a shank. Since the cutting head is a consumable part that is frequently replaced, and the material requirements for the cutting head are high, the cutting head and the shank are designed as separate parts. Therefore, the connection method between the cutting head and the shank is a key research issue in this field. Reamers are often used for the finishing of workpieces, and it is required that the coaxiality error between the cutting head and the shank after installation does not exceed 0.01mm. To meet this requirement, double positioning is required when the cutting head and the shank are connected.

[0004] Currently, such as Figure 1 As shown, the connection between the cutter head and the cutter shank is a threaded connection. The connecting part has an external thread, and the cutter shank has an internal thread that mates with it. The connecting part near the back of the cutter head is an inclined conical surface, and the upper end of the cutter shank has an inclined surface that mates with the inclined conical surface. That is, positioning is achieved through the back of the cutter head and the upper end of the cutter shank, and positioning is achieved through the engagement of the inclined surfaces, thus achieving dual positioning and meeting the connection requirements of the cutter head and the cutter shank.

[0005] However, the cutting head is generally made of cemented carbide, and the connecting part is relatively thin. Moreover, the coaxiality error between the cutting head and the tool holder must not exceed 0.01mm (that is, after the threaded connection, the back of the cutting head and the upper end face of the tool holder must be positioned, and the inclined surface must be matched to achieve positioning). The thread accuracy requirements are very high. Therefore, it is very difficult to open high-precision threads on the connecting part. In other words, the process of opening high-precision threads is very complex, resulting in high production costs for reamer heads. At the same time, the dual positioning of the conical surface and the end face, and the dimensional requirements of the joint point between the conical surface and the end face are extremely high, making the machining very difficult. Therefore, it is necessary to design a new type of connection method between the cutting head and the tool holder. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention discloses a connection structure and usage method of a replaceable head reamer, which reduces the production cost of the head while satisfying the dual positioning of the head and the shank, and is more conducive to market promotion and use.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A connection structure for a replaceable head reamer includes:

[0009] The cutting head is made of a single alloy or a single metal-ceramic material. The cutting head includes a cutting edge and a connecting part. The cross-section of the connecting part is non-circular, and the connecting part has an annular groove. The positional accuracy requirement of the annular groove is very low, resulting in low production cost.

[0010] A connecting sleeve includes a connecting sleeve head that is clearance-fitted with the outer surface of the connecting part, and a plurality of ball bearing through holes are formed around the connecting sleeve head at positions corresponding to the annular groove of the connecting part; the connecting sleeve head has balls in the ball bearing through holes, and the connecting sleeve also includes a connecting sleeve tail, the outer surface of the connecting sleeve tail is provided with external threads, and the connecting sleeve head and the connecting sleeve tail are concentric shafts.

[0011] The tool holder has a first groove for fitting the head of the connecting sleeve, a ball ring groove is formed on the inner wall of the first groove, a second groove is formed on the bottom surface of the first groove, and an internal thread that mates with the threaded end of the connecting sleeve is formed on the inner wall of the second groove.

[0012] The diameter of the ball is greater than the radius difference between the inner wall of the first groove of the cutter bar and the connecting part. When the cutter head, connecting sleeve and cutter bar are engaged, one side of the ball abuts against the inner wall of the first groove of the cutter bar, and the lower part of the other side of the ball abuts against the lower part of the annular groove of the connecting part, so as to achieve ball positioning and centering. When the cutter head, connecting sleeve and cutter bar are engaged, the lower end face of the cutting edge part contacts the upper end face of the cutter bar to achieve positioning.

[0013] As a further description of the above technical solution:

[0014] The cross-section of the connecting part is in the shape of an outer nut, and the interior of the connecting sleeve head is in the shape of an inner nut that contacts and fits with the connecting part.

[0015] As a further description of the above technical solution:

[0016] The longitudinal section of the annular groove in the connecting part is non-circular, and it is formed by upper and lower inclined surfaces.

[0017] As a further description of the above technical solution:

[0018] The downward inclination angle of the annular groove in the connecting part is 20-60°.

[0019] As a further description of the above technical solution:

[0020] The outer surfaces of both the head and tail of the connecting sleeve are cylindrical.

[0021] As a further description of the above technical solution:

[0022] The plurality of ball bearing through holes are evenly distributed on the head of the connecting sleeve; there are 6 ball bearing through holes.

[0023] As a further description of the above technical solution:

[0024] The distance between the ball ring groove of the tool holder and the bottom of the first groove is greater than the distance between the ball through hole of the connecting sleeve head and the bottom of the connecting sleeve head.

[0025] As a further description of the above technical solution:

[0026] The distance between the ball bearing through hole at the head of the connecting sleeve and the bottom of the head of the connecting sleeve is equal to the distance between the annular groove of the connecting part and the bottom of the connecting part.

[0027] As a further description of the above technical solution:

[0028] The first groove and the second groove of the tool holder are concentric stepped holes.

[0029] A method for using a connection structure for a replaceable head reamer includes the following steps:

[0030] S1: Insert the ball into the ball through hole of the connecting sleeve head;

[0031] S2: Place the connecting sleeve into the tool holder, rotate the connecting sleeve, and connect the connecting sleeve with the second groove thread of the tool holder through the tail of the connecting sleeve, so that the connecting sleeve is rotated into the tool holder. When the ball ring groove of the tool holder is in the corresponding position of the ball through hole, part of the ball enters the ball ring groove of the tool holder.

[0032] S3: When the connecting part is inserted into the head of the connecting sleeve, and the annular groove of the connecting part is located at the corresponding position of the ball through hole, the ball is squeezed by the tool bar so that part of the ball enters the annular groove of the tool head.

[0033] S4: Rotate the cutter head, which drives the connecting sleeve to rotate together, allowing the cutter head and connecting sleeve to continue to penetrate deeper into the tool holder. As the cutter head and connecting sleeve continue to penetrate deeper into the tool holder, the balls are pushed downwards and exit the ball ring groove of the tool holder. The balls, cutter head, and connecting sleeve move downwards together until the lower end face of the cutting edge contacts the upper end face of the tool holder. At this point, the lower end face of the cutting edge contacts and positions itself against the upper end face of the tool holder. Simultaneously, multiple balls are subjected to the force of the inner wall of the tool holder, giving them both downward and centripetal forces. The centripetal force achieves centering and positioning, which, combined with the contact positioning, achieves dual positioning. The downward force can lock the cutter head and tool holder, meeting the requirements for precision and strength of the connection between the cutter head and tool holder for finishing.

[0034] S5: When changing the cutter head, rotate the cutter head in the opposite direction. The cutter head and connecting sleeve will retract outside the cutter bar. When the ball ring groove moves to the position corresponding to the ball through hole, the ball is subjected to the reaction force of the annular groove of the connecting part, causing the ball to retract from the annular groove of the connecting part. Part of the ball enters the ball ring groove of the cutter bar. At this time, the cutter head can be pulled upward to replace it.

[0035] The present invention has the following beneficial effects:

[0036] This invention provides a connection structure and usage method for a replaceable-head reamer. The invention utilizes multiple ball bearings subjected to force from the inner wall of the tool shank, creating both downward and centripetal forces. The centripetal force achieves centering and positioning, which, combined with contact surface positioning, achieves dual positioning. The downward force locks the tool head and tool shank together, meeting the requirements for precision machining of the hole after the tool head and tool shank are connected. By creating threads on the connecting sleeve, which can be made of the same steel material as the tool shank, the tool head manufacturing only requires simple outer diameter machining, significantly reducing the production cost of the reamer head. Furthermore, in replaceable-head tools, the tool head is a consumable part, so reducing its cost is crucial; the reduced machining difficulty will greatly lower the user's operating costs.

[0037] In addition, the present invention uses ball bearings for positioning, which does not require high precision in the fit between the cutter head and the connecting sleeve, or between the connecting sleeve and the cutter bar. That is, even if there is a certain gap between the cutter head and the connecting sleeve, or between the connecting sleeve and the cutter bar, it will not affect the dual positioning of the cutter head and the cutter bar, which greatly reduces the processing technology and cost of the cutter head and the cutter bar. Attached Figure Description

[0038] Figure 1 This is a schematic diagram illustrating the connection between the cutting head and the cutting shank in existing technology.

[0039] Figure 2 A longitudinal cross-sectional schematic diagram of a connection structure for a replaceable head reamer provided by the present invention;

[0040] Figure 3 A longitudinal cross-sectional schematic diagram of the tool holder of a replaceable head reamer connection structure provided by the present invention;

[0041] Figure 4 A longitudinal cross-sectional view of the cutting head of a replaceable head reamer connection structure provided by the present invention;

[0042] Figure 5 A bottom view of the cutting head of a replaceable head reamer connection structure provided by the present invention;

[0043] Figure 6 A longitudinal cross-sectional schematic diagram of the connecting sleeve of the connecting structure for a replaceable head reamer provided by the present invention;

[0044] Figure 7A cross-sectional schematic diagram of the connecting sleeve of the connecting structure for a replaceable head reamer provided by the present invention;

[0045] Figure 8 This is a schematic diagram of the structure of the present invention when the lower end face of the cutting edge is in contact with the upper end face of the tool holder;

[0046] Figure 9 This is a partial schematic diagram of the force positioning of the invention when the lower end face of the cutting edge contacts the upper end face of the tool holder.

[0047] Reference numerals: 1-Tool holder; 11-Second groove; 12-First groove; 13-Ball ring groove; 14-Upper end face of tool holder; 2-Tool head; 21-Cutting edge portion; 22-Connecting portion; 23-Annular groove; 24-External hexagonal nut structure; 25-Lower end face of cutting edge portion; 3-Connecting sleeve; 31-Connecting sleeve head; 32-Connecting sleeve tail; 33-Ball through hole; 34-Internal hexagonal nut structure; 4-Ball. Detailed Implementation

[0048] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] This invention does not limit the specific type of rolling element to steel balls, steel balls, iron balls, glass balls, etc., because different industries choose different types of rolling elements; that is to say, any rolling elements such as steel balls, steel balls, iron balls, glass balls, etc. used in the connection structure of the replaceable head reamer protected by this invention are within the scope of protection of this invention.

[0051] Example 1

[0052] like Figure 2-7 As shown, a connecting structure for a replaceable head reamer includes a cutter head 2, a connecting sleeve 3, a ball bearing 4, and a cutter shank 1.

[0053] The cutter head 2 is made of integral alloy or integral metal ceramic. The cutter head 2 includes a cutting edge portion 21 and a connecting portion 22. The cross-section of the connecting portion 22 is a non-circular structure, and the connecting portion 22 has an annular groove 23.

[0054] In this embodiment, the cutter head 2 is made of integral alloy or integral metal-ceramic material. The present invention does not limit the specific material of the cutter head, and those skilled in the art can choose according to the actual situation.

[0055] The connecting sleeve 3 includes a connecting sleeve head 31 that is clearance-fitted with the outer surface of the connecting portion 22, and the connecting sleeve head 31 has a plurality of ball bearing through holes 23 at corresponding positions on the annular groove 23 of the connecting portion 22 around its periphery; the connecting sleeve head 31 has balls 4 inside the ball bearing through holes 33; the connecting sleeve 3 also includes a connecting sleeve tail 32, the outer surface of which has external threads; the connecting sleeve head 31 and the connecting sleeve tail 32 are concentric shafts. The outer surfaces of both the connecting sleeve head 31 and the connecting sleeve tail 32 are cylindrical surfaces.

[0056] In this embodiment, the connecting sleeve 3 is made of steel. The present invention does not limit the specific material of the connecting sleeve, and those skilled in the art can choose according to the actual situation.

[0057] The tool holder 1 has a first groove 12 for fitting the head of the connecting sleeve. The tool holder 1 has a ball ring groove 13 on the inner wall of the first groove 12. The tool holder 1 has a second groove 11 on the bottom surface of the first groove. The tool holder 1 has an internal thread on the inner wall of the second groove 11 that is threaded to the tail 32 of the connecting sleeve. The first groove 12 and the second groove 11 of the tool holder 1 are concentric stepped holes.

[0058] In this embodiment, the tool holder 1 is made of steel. This invention does not limit the specific material of the tool holder, and those skilled in the art can choose according to the actual situation.

[0059] The diameter of the ball 4 is greater than the radius difference between the inner wall of the first groove 12 of the cutter bar 1 and the connecting part 22. When the cutter head 2, the connecting sleeve 3 and the cutter bar 1 are engaged, one side of the ball 4 abuts against the inner wall of the first groove 12 of the cutter bar 1, and the lower part of the other side of the ball 4 abuts against the lower part of the annular groove 23 of the connecting part of the cutter head 2, so as to realize the positioning and centering of the ball 4. When the cutter head 2, the connecting sleeve 3 and the cutter bar 1 are engaged, the lower end face 25 of the cutting edge part contacts the upper end face 14 of the cutter bar to achieve positioning.

[0060] The cross-section of the connecting part 22 is in the shape of an external nut, specifically an external hexagonal nut 24; the interior of the connecting sleeve head 31 is in the shape of an internal nut that contacts and fits with the connecting part 22, specifically an internal hexagonal nut 34.

[0061] The longitudinal section of the annular groove of the connecting part 22 is non-circular, formed by upper and lower inclined surfaces; the downward inclination angle of the annular groove of the connecting part 22 is 20-60°. Preferably, the downward inclination angle of the annular groove of the connecting part 22 is 30°. When the cutter head 2, connecting sleeve 3 and cutter bar 1 are engaged, one side of the ball 4 abuts against the inner wall of the first groove 12 of the cutter bar 1, and the lower part of the other side of the ball 4 abuts against the downward inclination surface of the annular groove 23 of the connecting part 22, thereby achieving positioning and centering of the ball 4; when the cutter head 2, connecting sleeve 3 and cutter bar 1 are engaged, the cutting edge part 21 contacts the end face of the cutter bar 1 to achieve positioning.

[0062] A plurality of ball bearing through holes 33 are evenly distributed on the head 31 of the connecting sleeve; there are six ball bearing through holes 33. The centripetal forces are canceled out by the six evenly distributed balls 4, thus completing centering and positioning.

[0063] The distance between the ball ring groove 13 of the tool holder 1 and the bottom of the first groove 12 is greater than the distance between the ball through hole 33 of the connecting sleeve head 31 and the bottom of the connecting sleeve head 31, which makes it easier for the tool head 2 and the connecting sleeve 3 to continue to penetrate into the tool holder 1, so as to achieve contact positioning between the cutting edge part 21 and the end face of the tool holder 1.

[0064] The distance between the ball bearing through hole 33 of the connecting sleeve head 32 and the bottom of the connecting sleeve head 32 is equal to the distance between the annular groove 23 of the connecting part 22 and the bottom of the connecting part 22. When the end of the connecting part 22 is located at the bottom of the connecting sleeve head 31, the ball bearing through hole 33 of the connecting sleeve head 31 corresponds to the annular groove 23 of the connecting part 22, which facilitates a portion of the ball bearing 4 entering the annular groove 23.

[0065] Example 2

[0066] A method for using a connection structure for a replaceable head reamer includes the following steps:

[0067] S1: Insert the ball bearing 4 into the ball bearing through hole 33 of the head 31 of the connecting sleeve;

[0068] S2: Place the connecting sleeve 3 into the tool bar 1, rotate the connecting sleeve 3, and connect the connecting sleeve 3 with the second groove 11 of the tool bar 1 through the threaded engagement of the tail 32 of the connecting sleeve, so that the connecting sleeve 3 is rotated into the tool bar 1. When the ball ring groove 13 of the tool bar 1 is located at the corresponding position of the ball through hole 33, a part of the ball 4 enters the ball ring groove 13 of the tool bar 1.

[0069] S3: When the connecting part 22 is inserted into the connecting sleeve head 31, and the annular groove of the connecting part 31 is located at the corresponding position of the ball through hole 33, the ball 4 is squeezed by the inner wall of the tool holder 1, causing a part of the ball 4 to enter the annular groove 23 of the tool head 2.

[0070] S4: Rotate the cutter head 2, which drives the connecting sleeve 3 to rotate together, allowing the cutter head 2 and connecting sleeve 3 to continue penetrating deeper into the tool holder 1. As the cutter head 2 and connecting sleeve 3 continue to penetrate deeper into the tool holder 1, the balls 4 are pushed downwards and exit the ball ring groove 13 of the tool holder. The balls 4, cutter head 2, and connecting sleeve 3 move downwards together until the lower end face 25 of the cutting edge contacts the upper end face 14 of the tool holder. At this point, the lower end face 25 of the cutting edge contacts and positions itself against the upper end face 14 of the tool holder. Simultaneously, multiple balls 4 are subjected to force from the inner wall of the tool holder 1, resulting in both downward and centripetal forces. The centripetal force achieves centering and positioning, which, combined with the contact positioning, achieves dual positioning. The downward force can lock the cutter head and tool holder, meeting the requirements for precision and strength of the connection between the cutter head and tool holder for finishing (e.g., ...). Figure 8-9 (as shown);

[0071] S5: When replacing the cutter head 2, rotate the cutter head 2 in the opposite direction. The cutter head 2 and the connecting sleeve 3 will retract outside the cutter bar 1. When the ball ring groove 13 moves to the position corresponding to the ball through hole 33, the ball 4 will be subjected to the reaction force of the annular groove 23 of the connecting part 22, causing the ball 4 to retract from the annular groove 23 of the connecting part. Part of the ball 4 will enter the ball ring groove 13 of the cutter bar. At this time, the cutter head 2 can be pulled out upwards for replacement.

[0072] This invention provides a connection structure and usage method for a replaceable-head reamer. Multiple balls 4 are subjected to force from the inner wall of the tool holder, resulting in both downward and centripetal forces. The centripetal force achieves centering and positioning, which, combined with contact surface positioning, achieves dual positioning. The downward force locks the tool head 2 and tool holder 1, meeting the requirements for precision machining of the hole after the tool head 2 and tool holder 1 are connected. This invention allows for threading on the connecting sleeve 3, which can be made of the same steel material as the tool holder 1. Manufacturing the tool head 2 only requires simple outer diameter machining, significantly reducing the production cost of the reamer head. Furthermore, in replaceable-head tools, the tool head 2 is a consumable part, making cost reduction a key focus. The reduced machining difficulty will significantly lower the user's operating costs.

[0073] In addition, the present invention uses ball bearings 4 for positioning, which does not require the precision of the fit between the cutter head 2 and the connecting sleeve 3, or between the connecting sleeve 3 and the cutter bar 1. That is, the existence of a certain gap between the cutter head 2 and the connecting sleeve 3, or between the connecting sleeve 3 and the cutter bar 1, does not affect the dual positioning of the connection between the cutter head 2 and the cutter bar 1, which greatly reduces the processing technology and cost of the cutter head and the cutter bar.

[0074] In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0075] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0076] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A connection structure for a replaceable head reamer, characterized in that, include: The cutting head is made of integral alloy or integral metal ceramic. The cutting head includes a cutting edge and a connecting part. The cross-section of the connecting part is non-circular and the connecting part has an annular groove. A connecting sleeve includes a connecting sleeve head that is clearance-fitted with the outer surface of the connecting part, and a plurality of ball bearing through holes are formed around the connecting sleeve head at positions corresponding to the annular groove of the connecting part; the connecting sleeve head has balls in the ball bearing through holes, and the connecting sleeve also includes a connecting sleeve tail, the outer surface of the connecting sleeve tail is provided with external threads, and the connecting sleeve head and the connecting sleeve tail are concentric shafts. The tool holder has a first groove for fitting the head of the connecting sleeve, a ball ring groove is formed on the inner wall of the first groove, a second groove is formed on the bottom surface of the first groove, and an internal thread that mates with the threaded end of the connecting sleeve is formed on the inner wall of the second groove. The diameter of the ball is greater than the radius difference between the inner wall of the first groove of the cutter bar and the connecting part. When the cutter head, connecting sleeve and cutter bar are engaged, one side of the ball abuts against the inner wall of the first groove of the cutter bar, and the lower part of the other side of the ball abuts against the lower part of the annular groove of the connecting part, so as to achieve ball positioning and centering. When the cutter head, connecting sleeve and cutter bar are engaged, the lower end face of the cutting edge part contacts the upper end face of the cutter bar to achieve positioning.

2. The connection structure of a replaceable head reamer according to claim 1, characterized in that, The cross-section of the connecting part is in the shape of an outer nut, and the interior of the connecting sleeve head is in the shape of an inner nut that contacts and fits with the connecting part.

3. The connection structure of a replaceable head reamer according to claim 2, characterized in that, The longitudinal section of the annular groove in the connecting part is non-circular, and it is formed by upper and lower inclined surfaces.

4. The connection structure of a replaceable head reamer according to claim 3, characterized in that, The downward inclination angle of the annular groove in the connecting part is 20-60°.

5. The connection structure of a replaceable head reamer according to claim 1, characterized in that, The outer surfaces of both the head and tail of the connecting sleeve are cylindrical.

6. The connection structure of a replaceable head reamer according to claim 5, characterized in that, The plurality of ball bearing through holes are evenly distributed on the head of the connecting sleeve; there are 6 ball bearing through holes.

7. The connection structure of a replaceable head reamer according to claim 6, characterized in that, The distance between the ball ring groove of the tool holder and the bottom of the first groove is greater than the distance between the ball through hole of the connecting sleeve head and the bottom of the connecting sleeve head.

8. The connection structure of a replaceable head reamer according to claim 7, characterized in that, The distance between the ball bearing through hole at the head of the connecting sleeve and the bottom of the head of the connecting sleeve is equal to the distance between the annular groove of the connecting part and the bottom of the connecting part.

9. The connection structure of a replaceable head reamer according to claim 1, characterized in that, The first groove and the second groove of the tool holder are concentric stepped holes.

10. A method of using the connecting structure of a replaceable head reamer according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Insert the ball into the ball through hole of the connecting sleeve head; S2: Place the connecting sleeve into the tool bar, rotate the connecting sleeve, and connect the connecting sleeve with the second groove of the tool bar through the threaded engagement of the tail of the connecting sleeve, so that the connecting sleeve is rotated into the tool bar. When the ball ring groove of the tool bar is located at the corresponding position of the ball through hole, a part of the ball enters the ball ring groove of the tool bar. S3: When the connecting part is inserted into the head of the connecting sleeve, and the annular groove of the connecting part is located at the corresponding position of the ball through hole, the ball is squeezed by the tool bar so that part of the ball enters the annular groove of the tool head. S4: Rotate the cutter head, which drives the connecting sleeve to rotate together, allowing the cutter head and connecting sleeve to continue to penetrate deeper into the tool holder. As the cutter head and connecting sleeve continue to penetrate deeper into the tool holder, the balls are pushed downwards and disengage from the ball ring groove of the tool holder. The balls, cutter head, and connecting sleeve move downwards together until the lower end face of the cutting edge contacts the upper end face of the tool holder. At this point, the lower end face of the cutting edge contacts and positions itself against the upper end face of the tool holder. Simultaneously, multiple balls are subjected to the force of the inner wall of the tool holder, resulting in both downward and centripetal forces. The centripetal force achieves centering and positioning, which, combined with the contact positioning, achieves dual positioning. The downward force locks the cutter head and tool holder, meeting the requirements for precision and strength of the connection between the cutter head and tool holder for finishing. S5: When changing the cutter head, rotate the cutter head in the opposite direction. The cutter head and connecting sleeve will retract outside the cutter bar. When the ball through hole moves to the corresponding position in the ball ring groove, the ball is subjected to the reaction force of the annular groove of the connecting part, causing the ball to exit the annular groove of the connecting part. Part of the ball enters the ball ring groove of the cutter bar. At this time, the cutter head can be pulled upward to replace it.

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