Internal expansion chuck

Abstract

The utility model discloses an internal expansion chuck which comprises a chuck body and an expansion sleeve, a mounting part is arranged on the chuck body, and the internal expansion chuck is characterized in that a pull rod is coaxially arranged in the mounting part, the pull rod comprises a positioning head part and a pull rod part, the pull rod part is arranged in the mounting part in a front-back movable manner, and the positioning head part extends out of the mounting part. The expansion sleeve is provided with a cavity penetrating front and back, the cavity comprises a front-section cavity and a rear-section cavity, the inner diameter of the front-section cavity is gradually decreased from front to back, the inner diameter of the rear-section cavity is gradually increased from front to back, the positioning head is provided with a circular-truncated-cone-shaped opening portion with the outer diameter gradually decreased from front to back, and the front section of the mounting portion is a circular truncated cone with the outer diameter gradually increased from front to back. The expansion sleeve is arranged on the positioning head part and the mounting part in a sleeving manner, so that the opening part is arranged in the front-section cavity in a close-fitting manner, and the circular truncated cone is arranged in the rear-section cavity in a close-fitting manner. The expanding sleeve has the advantages that the structure is simple, the two ends of the expanding sleeve can be expanded in the diameter direction at the same time, stable clamping force is provided for a workpiece, and therefore the machining precision of the workpiece is guaranteed.

Description

Technical Field

[0001] The utility model relates to a chuck, in particular to an internal expansion chuck. Background Art

[0002] For tubular or shell-shaped workpieces, or workpieces with difficult-to-clamp exteriors, expansion sleeves are often used to expand the workpiece outward, clamp it within the workpiece's inner hole, and tighten the workpiece from the inside for easier machining. This is why internal expansion chucks have emerged. Currently, common internal expansion chucks have a limited range of workpieces they can clamp, often only ensuring expansion at one end. Therefore, if the workpiece to be machined is too long, this type of internal expansion chuck can only guarantee accuracy at one end. Because the other end is too long, the workpiece will be too long, resulting in different precision at both ends, whether machining directly or re-clamping. Summary of the Invention

[0003] The technical problem to be solved by the utility model is to provide an internal expansion chuck which has a simple structure and can effectively ensure the processing accuracy of a workpiece.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] An internal expansion chuck comprises a chuck body and an expansion sleeve, wherein the chuck body is provided with a mounting portion for mounting the expansion sleeve, a pull rod is coaxially arranged in the mounting portion, the pull rod comprises a positioning head and a pulling rod portion coaxially arranged in sequence from front to back, the pulling rod portion can be movably arranged in the mounting portion along the axial direction, the positioning head extends outward and is arranged outside the mounting portion, the expansion sleeve has a cavity that passes through from front to back, the cavity comprises a front section chamber located in the front end head of the expansion sleeve and a cavity located in the expansion sleeve The rear section chamber in the rear end head, the inner diameter of the front section chamber gradually decreases from front to back, and the inner diameter of the rear section chamber gradually increases from front to back. The positioning head has a truncated cone-shaped expansion part with an outer diameter gradually decreasing from front to back, which cooperates with the front section chamber. The front section of the mounting part is a truncated cone body with an outer diameter gradually increasing from front to back, which cooperates with the rear section chamber. The expansion sleeve is arranged on the positioning head and the mounting part, so that the expansion part is tightly fitted in the front section chamber, and the truncated cone body is tightly fitted in the rear section chamber.

[0006] The front and rear chambers are connected by a transition chamber, which together form the hollow chamber. The transition chamber can be used to increase the length of the expansion sleeve. A waist-shaped guide groove, which subsequently connects to the hollow chamber, can directly communicate with the transition chamber, working in conjunction with a guide pin to limit the twisting of the expansion sleeve during use.

[0007] The transition chamber is a cylindrical chamber with the same inner diameter from front to back, which is easy to process.

[0008] A connecting sleeve is disposed within the chuck body, allowing for forward and backward movement. The connecting sleeve is coaxially disposed with the pull rod, and the rear end of the pull rod is coaxially fixedly disposed with the connecting sleeve. The connecting sleeve is used to connect to a corresponding drive mechanism, which drives the connecting sleeve to move forward and backward, thereby driving the pull rod to move forward and backward stably.

[0009] The expansion part is an annular protrusion provided on the front part of the positioning head, and the outer diameter of the annular protrusion gradually decreases from the front to the back. The structure is simple and easy to manufacture.

[0010] The sidewall of the expansion sleeve is provided with a waist-shaped guide groove that communicates with the cavity. A guide pin is disposed within the waist-shaped guide groove. One end of the guide pin is movably disposed within the waist-shaped guide groove, while the other end of the guide pin is fixedly attached to the positioning head. The guide pin and waist-shaped guide groove cooperate to define the relative motion range between the pull rod and the expansion sleeve. Furthermore, when the expansion sleeve is reset, the guide pin can propel the expansion sleeve forward to its starting position.

[0011] A positioning pin is provided on the side of the chuck body, and a waist-shaped positioning groove is provided axially on the pull rod. The inner end of the positioning pin extends into the chuck body and is positioned within the waist-shaped positioning groove. The positioning pin and the waist-shaped positioning groove cooperate to limit the travel of the pull rod and prevent the pull rod from rotating.

[0012] A positioning backer is sleeved on the positioning head and removably fixed to the chuck body. The positioning backer is located behind the expansion sleeve. The positioning backer is used to position the workpiece and is removably connected to the chuck body, making it easy to replace different positioning backers according to different workpieces.

[0013] Compared with the prior art, the advantages of the present invention are: simple structure, wherein conical chambers are respectively provided at both ends of the expansion sleeve, and the two conical chambers respectively cooperate with the pull rod and the corresponding structures on the mounting part. When the pull rod is pulled backward, the expansion sleeve is driven to move backward synchronously, and the front chamber cooperates with the expansion part to realize the expansion of the front end of the expansion sleeve, and the rear chamber cooperates with the frustum to realize the expansion of the rear end of the expansion sleeve, so that the two ends of the expansion sleeve are simultaneously expanded along the diameter direction, increasing the contact area between the expansion sleeve and the inner hole of the workpiece, so as to provide a stable clamping force to the workpiece, thereby ensuring the processing accuracy of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic cross-sectional view of the utility model;

[0015] Figure 2 This is a schematic diagram of the three-dimensional structure of the pull rod in the utility model;

[0016] Figure 3 It is a schematic cross-sectional structural diagram of the expansion sleeve in the utility model. DETAILED DESCRIPTION

[0017] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0018] As shown in the figure, an internal expansion chuck includes a chuck body 1 and an expansion sleeve 2. The chuck body 1 is provided with a mounting portion 11 for mounting the expansion sleeve 2. A pull rod 3 is coaxially arranged in the mounting portion 11. The pull rod 3 includes a positioning head 31 and a pulling rod 32 coaxially arranged from front to back. The pulling rod 32 can be movably arranged in the mounting portion 11 along the axial direction. The positioning head 31 extends out of the mounting portion 11. The expansion sleeve 2 has a cavity 21 that passes through from front to back. The cavity 21 includes a front chamber 211 located in the front end head of the expansion sleeve 2 and a cavity 21 located in the expansion sleeve 2. The rear section chamber 212 in the rear end head, the front section chamber 211 has an inner diameter gradually decreasing from front to back, and the rear section chamber 212 has an inner diameter gradually increasing from front to back. The positioning head 31 has a truncated cone-shaped expansion portion 311 with an outer diameter gradually decreasing from front to back, which cooperates with the front section chamber 211. The front section of the mounting portion 11 is a truncated cone body 111 with an outer diameter gradually increasing from front to back, which cooperates with the rear section chamber 212. The expansion sleeve 2 is mounted on the positioning head 31 and the mounting portion 11, so that the expansion portion 311 is tightly fitted in the front section chamber 211, and the truncated cone body 111 is tightly fitted in the rear section chamber 212.

[0019] In this embodiment, the front chamber 211 and the rear chamber 212 are connected by a transition chamber 213, forming the cavity 21. The transition chamber 213 can be used to increase the length of the expansion sleeve 2. Furthermore, the waist-shaped guide groove 22, which is subsequently connected to the cavity 21, can directly communicate with the transition chamber 213 and, in conjunction with the guide pin 5, limit the twisting of the expansion sleeve 2 during use.

[0020] In this embodiment, the transition chamber 213 is a cylindrical chamber with the same inner diameter from front to back, which is easy to process.

[0021] In this embodiment, a connecting sleeve 4 is disposed within the chuck body 1 so as to be movable back and forth. The connecting sleeve 4 is coaxially disposed with the pull rod 3, and the rear end of the pull rod 32 is fixedly disposed coaxially with the connecting sleeve 4. The connecting sleeve 4 is used to connect to a corresponding drive mechanism, which drives the connecting sleeve 4 to move back and forth, thereby driving the pull rod 3 to move back and forth stably.

[0022] In this embodiment, the expansion portion 311 is an annular protrusion provided on the front portion of the positioning head 31, and the outer diameter of the annular protrusion gradually decreases from the front to the back.

[0023] In this embodiment, the sidewall of the expansion sleeve 2 is provided with a waist-shaped guide groove 22 that communicates with the cavity 21. A guide pin 5 is disposed within the waist-shaped guide groove 22. One end of the guide pin 5 is movably disposed within the waist-shaped guide groove 22, while the other end of the guide pin 5 is fixedly mounted on the positioning head 31. The cooperation between the guide pin 5 and the waist-shaped guide groove 22 serves to limit the relative motion between the pull rod 3 and the expansion sleeve 2. Furthermore, when the expansion sleeve 2 is reset, the guide pin 5 can push the expansion sleeve 2 forward to its starting position.

[0024] In this embodiment, a locating pin 6 is provided on the side of the chuck body 1, and a waist-shaped locating groove 321 is provided axially on the pull rod 32. The inner end of the locating pin 6 extends into the chuck body 1 and is disposed within the waist-shaped locating groove 321. The locating pin 6 and the waist-shaped locating groove 321 cooperate to limit the travel of the pull rod 3 and prevent the pull rod 3 from rotating.

[0025] In this embodiment, a positioning support 7 is sleeved and mounted on the positioning head 31. The positioning support 7 is detachably fixed to the chuck body 1 and is located behind the expansion sleeve 2. The positioning support 7 is used to position the workpiece and is detachably connected to the chuck body 1, making it easy to replace different positioning supports 7 according to different workpieces.

[0026] This product has good versatility. For workpieces with different inner diameters, it is only necessary to replace different expansion sleeves 2, which effectively saves costs.

Claims

1. An internal expansion chuck, comprising a chuck body and an expansion sleeve, wherein the chuck body is provided with a mounting portion for mounting the expansion sleeve, characterized in that A pull rod is coaxially arranged in the mounting portion, and the pull rod includes a positioning head and a pulling rod portion coaxially arranged in sequence from front to back, and the pulling rod portion can be movably arranged in the mounting portion axially forward and backward, and the positioning head extends outward and is arranged outside the mounting portion, and the expansion sleeve has a cavity that passes through from front to back, and the cavity includes a front section chamber located in the front end head of the expansion sleeve and a rear section chamber located in the rear end head of the expansion sleeve, the inner diameter of the front section chamber gradually decreases from front to back, and the inner diameter of the rear section chamber gradually increases from front to back, the positioning head has a truncated cone-shaped expansion portion with an outer diameter gradually decreasing from front to back that cooperates with the front section chamber, and the front section of the mounting portion is a truncated cone body with an outer diameter gradually increasing from front to back that cooperates with the rear section chamber, and the expansion sleeve is arranged on the positioning head and the mounting portion, so that the expansion portion is tightly fitted in the front section chamber, and the truncated cone body is tightly fitted in the rear section chamber.

2. An internal expansion chuck according to claim 1, characterized in that The front section chamber and the rear section chamber are connected via a transition chamber, and the front section chamber, the transition chamber and the rear section chamber constitute the cavity.

3. An internal expansion chuck according to claim 2, characterized in that The transition chamber is a cylindrical chamber with the same inner diameter from front to back.

4. The internal expansion chuck according to claim 1, characterized in that A connecting sleeve is movably arranged in the chuck body. The connecting sleeve is coaxially arranged with the pull rod. The rear end of the pull rod is coaxially fixedly arranged with the connecting sleeve.

5. The internal expansion chuck according to claim 1, characterized in that The expansion portion is an annular protrusion arranged on the front section of the positioning head, and the outer diameter of the annular protrusion gradually decreases from the front to the back.

6. The internal expansion chuck according to claim 1, characterized in that A waist-shaped guide groove connected to the cavity is provided on the side wall of the expansion sleeve, and a guide pin is provided in the waist-shaped guide groove. One end of the guide pin can be movably arranged in the waist-shaped guide groove, and the other end of the guide pin is fixedly arranged on the positioning head.

7. The internal expansion chuck according to claim 1, characterized in that A positioning pin is provided on the side of the chuck body, a waist-shaped positioning groove is axially provided on the pulling rod, and the inner end of the positioning pin extends into the chuck body and is arranged in the waist-shaped positioning groove.

8. The internal expansion chuck according to claim 1, characterized in that A positioning backer is sleeved and mounted on the positioning head. The positioning backer is detachably fixed on the chuck body. The positioning backer is arranged behind the expansion sleeve.

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