Vibration absorption cutter holder

A cutter holder has a body, a fastening bolt, and a vibration absorbing structure. The body has a specific weight. The fastening bolt is mounted inside the body. The vibration absorbing structure is mounted inside the body and has a sleeve, an elastic unit, a spacer, and a set nut. The sleeve is mounted around the fastening bolt and has a specific weight. The specific weight of the sleeve is larger than the specific weight of the body. The elastic unit is mounted around the fastening bolt and has two opposite ends. One of the ends of the elastic unit abuts against the sleeve. The spacer is mounted around the fastening bolt and abuts against the other end of the elastic unit. The set nut is screwed with the fastening bolt and abuts against the spacer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a machine tool, and more particularly to a cutter holder that can absorb vibration caused by machining.

2. Description of Related Art

A cutter holder is a tool for machining. With reference toFIG. 4, a conventional cutter holder80comprises a body81, a collet82, a cutter83, a fastening bolt84, and a set screw85. The body81has a first end and a second end opposite the first end. The collet82is mounted in the first end of the body81. The cutter83is mounted in the collet82. The fastening bolt84is screwed in the body81and is adjacent to the second end of the body81. The conventional cutter holder80inevitably generates vibration during machining. The vibration has little influence on processing quality when utilizing cutter holders with shorter lengths. However, for certain cutter holders with longer lengths, the vibration forms obvious marks of machining and a rough surface on a work piece. The conventional cutter holder80lacks vibration absorbing structures and consequently is not suitable for larger work pieces.

To overcome the shortcomings of the conventional cutter holder, the present invention provides a vibration absorption cutter holder to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a vibration absorption cutter holder that can absorb vibration caused by machining and perform high-quality machining.

The cutter holder comprises a body, a fastening bolt, and a vibration absorbing structure. The body has a specific weight. The fastening bolt is mounted inside the body. The vibration absorbing structure is mounted inside the body and has a sleeve, an elastic unit, a spacer, and a set nut. The sleeve is mounted around the fastening bolt and has a specific weight. The specific weight of the sleeve is larger than the specific weight of the body. The elastic unit is mounted around the fastening bolt and has two opposite ends. One of the ends of the elastic unit abuts against the sleeve. The spacer is mounted around the fastening bolt and abuts against the other end of the elastic unit. The set nut is screwed with the fastening bolt and abuts against the spacer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

With reference toFIGS. 1, 2A, 2B, and 3, a vibration absorption cutter holder in accordance with the present invention comprises a body10, a fastening bolt20, a set screw30, a vibration absorbing structure40, a collet50, and a cutter60. The fastening bolt20, the set screw30, and the vibration absorbing structure40are mounted inside the body10. The collet50is assembled on the body10.

With reference toFIGS. 1, 2A, 2B, and 3, the body10has a specific weight, a clamping end, a cutting end, a through hole11, a receiving hole12, and a connecting hole13. The through hole11is axially formed in the clamping end of the body10. The through hole11has a diameter, an inner surface, and an inner thread formed on the inner surface of the through hole11. The inner thread of the through hole11is adjacent to the clamping end of the body10. The receiving hole12is axially formed in the cutting end of the body10. The receiving hole12has an inner surface, a first end, a second end, and a receiving groove121. The first end of the receiving hole12corresponds in position to the cutting end of the body10and is conical. The second end of the receiving hole12is opposite to the first end of the receiving hole12. The second end of the receiving hole12has a diameter. The receiving groove121is annularly formed in the inner surface of the receiving hole12and is adjacent to the cutting end of the body10. A seal is mounted in the receiving groove121. The connecting hole13is axially formed in the body10and communicates with the through hole11and the receiving hole12. The connecting hole13has a diameter. The diameter of the connecting hole13is smaller than the diameters of the through hole11and the second end of the receiving hole12.

With reference toFIGS. 2A, 2B, and 3, the fastening bolt20has two opposite ends, a bolt head21, a threaded section22, and a smooth section23. The bolt head21and the threaded section22are respectively disposed at the two ends of the fastening bolt20. The smooth section23is disposed between the bolt head21and the threaded section22. The fastening bolt20is inserted in the through hole11of the body10from the clamping end of the body10. The bolt head21of the fastening bolt20abuts against a portion formed between the through hole11and the connecting hole13. The threaded section22and the smooth section23are held in the receiving hole12.

With reference toFIGS. 2A, 2B, and 3, the set screw30is inserted in the through hole11from the clamping end of the body10and is screwed with the inner thread of the through hole11. The set screw30is used for preventing the fastening bolt20from dropping out from the through hole11and for limiting a stroke of the fastening bolt20.

With reference toFIGS. 2A, 2B, and 3, the vibration absorbing structure40has a sleeve41, an elastic unit42, a spacer43, and a set nut44. The sleeve41is held in the receiving hole12of the body10and is mounted around the smooth section23of the fastening bolt20.

With reference toFIGS. 3, 4A, and 4B, the sleeve41has a first end, a second end, and a positioning protrusion411. The first end of the sleeve41faces to the cutting end of the body10. The second end of the sleeve41faces to the clamping end of the body10. The first end and the second end of the sleeve41are opposite each other. The positioning protrusion411is formed on and protrudes axially from the first end of the sleeve41, extends toward the cutting end of the body10and has two opposite sides4111. The sleeve41has a specific weight larger than the specific weight of the body10, and more particularly the sleeve41is made of tungsten alloy. The elastic unit42has two opposite ends. The elastic unit42is mounted around the fastening bolt20. One of the ends of the elastic unit42abuts against the sleeve41.

With reference toFIGS. 3, 4A, and 4B, in the embodiment of the present invention, the elastic unit42is a compression spring. The elastic unit42has an outline of a spiral spring and two string ends421. One of the two string ends421abuts against one of the two opposite sides4111of the positioning protrusion411.

The spacer43is held in the receiving hole12and is mounted around the fastening bolt20. The spacer43abuts against the other end of the elastic unit42. The set nut44has an inner surface, an outer surface, an inner thread formed on the inner surface of the set nut44, and multiple annular grooves441. The annular grooves441are radially formed in the outer surface of the set nut44and extend to the inner surface of the set nut44. The set nut44is held in the receiving hole12, is screwed with the threaded section22of the fastening bolt20, and abuts against the spacer43. The set nut44screwed with the threaded section22can reciprocate toward the cutting end or the clamping end of the body10.

With reference toFIGS. 1, 2A, 2B, and 3, the collet50has two opposite ends and is held in the receiving hole12of the body10. One of the ends of the collet50extends out of the body10. The other end of the collet50is screwed with the threaded section22of the fastening bolt20.

With reference toFIGS. 4A and 4B, since one of the two string ends421of the elastic unit42is blocked by one of the two opposite sides4111of the positioning protrusion411, the elastic unit42is able to be stably located between the sleeve41and spacer43abutted by the set nut44. In addition, the elastic unit42does not easily rotate in the receiving hole12. Therefore, the elastic unit42firmly abuts against both the sleeve41and the spacer43. The sleeve41and the elastic unit42provide a good buffering effect and absorb vibration efficiently.

The set nut44is able to reciprocate toward the cutting end or the clamping end of the body10along the threaded section22of the fastening bolt20, and can fine tune buffer capability of the cutter holder in accordance with the present invention according to the actual degree of vibration. The annular grooves441of the set nut44provide the set nut44with flexibility. The set nut44with annular grooves441facilitates vibration absorption of the cutter holder in accordance with the present invention.

With reference toFIGS. 1, 2A, 2B, and 3, the cutter60has two opposite ends and a cutting portion61. The cutting portion61is formed at one of the ends of the cutter60. The other end of the cutter60is mounted in the collet50. The cutting portion61extends out of the collet50.

The sleeve41is made of the material that has the larger specific weight than the body10. The sleeve41and the elastic unit42are used for vibration absorption. The cutter holder in accordance with the present invention not only provides a smoother machined surface, diminishes the negative influence on the machining quality, but also resolves the noise problem caused by machining.