Collet bushings and tool drive devices

Abstract

To provide a collet bush and a tool drive device capable of securing both vibration prevention of a tool and dust absorption force of chips when performing positioning of a hand-held tool drive device which has a dust adsorption function of chips with respect to a workpiece.SOLUTION: A collet bush that is such a collet bush as to be inserted to a concentric collet which is to be attached to a prescribed tool drive device in order to perform positioning concerning a workpiece has a tapered cylindrical outer surface for widening the concentric collet and a cylindrical inner surface which forms a through-hole for sliding the tool and a flow path for taking in air for dust absorbing to an inner part of the collet bush. Further, the tool driving device includes the above-described collet bush and the prescribed concentric collet.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present invention relate to a collet bush and a tool driving device. Background Art

[0002] When drilling a workpiece to be drilled using a hand-held tool driving device, it is necessary to position the tool driving device relative to the workpiece. A concentric collet is known as one of tools for this purpose (see, for example, Patent Document 1).

[0003] The concentric collet has a cylindrical structure having a plurality of slits, and the diameter of the concentric collet is expanded when a tapered bush is inserted into an inner tapered through hole. Therefore, in a state where the concentric collet is inserted into a positioning hole provided in a drilling jig such as a drilling plate fixed to the workpiece, when the tapered bush provided as a nosepiece on the tool driving device is inserted into the inner side of the concentric collet, the diameter of the concentric collet expands, and the tool driving device can be positioned and fixed to the drilling jig.

[0004] When drilling a workpiece using a hand-held tool driving device, it is desirable to enable collection of cutting chips. Accordingly, there is also known a tool driving device that has a cutting chip dust suction function and allows use of a concentric collet (see, for example, Patent Document 2 and Non-Patent Document 1). Prior Art Documents Patent Documents

[0005] Patent Document 1 US Patent No. 5628592 Specification Patent Document 2 US Patent No. 10994344 Specification Non-Patent Documents

[0006] Non-Patent Document 1 DESOUTTER Industrial Tools, Catalog, [online], [Accessed July 20, 2022], Internet <URL:https: / / us.desouttertools.com / uploads / documents / 5dd3f490cb9aa_Desoutter%20Aerospace%20Catalog_ENG.pdf> [Overview of the project] [Problems that the invention aims to solve]

[0007] However, when using a concentric collet for dust collection, the gap between the collet bush and the drill becomes the air passage for dust collection. Therefore, if the collet bush, which is slidably fitted to the drill shank to prevent drill runout, is inserted into the concentric collet, the air passage becomes narrow, which can result in insufficient dust collection.

[0008] Conversely, if the gap between the drill shank and the collet bush is widened to ensure sufficient dust collection, the drill shank will no longer slide smoothly against the collet bush, which creates a problem in preventing drill runout.

[0009] Therefore, the present invention aims to achieve both prevention of tool runout and securing of chip collection force when positioning a handheld tool drive device with a chip collection function relative to a workpiece is performed by a concentric collet. [Means for solving the problem]

[0010] The collet bush according to an embodiment of the present invention is a collet bush inserted into a concentric collet attached to a handheld tool drive device that holds, rotates, and feeds a tool and has a chip collection function, in order to position the tool drive device on a workpiece. This collet bush is , a tapered cylindrical outer surface for widening the concentric collet, and for sliding the tool First forming a through hole The collet bush has a first inner surface formed on the tip side of the collet bush, and a second inner surface formed on the rear end side of the collet bush, which has a larger diameter than the first inner surface. a cylindrical inner surface, and a flow path for taking in dust suction air into the inside of the collet bush The second through-hole is formed between the outer surface and the first inner surface as the passage for taking in the dust-collecting air. This second through-hole has one end opening at the end face on the tip side of the collet bush and the other end opening at an annular stepped surface formed between the first inner surface and the second inner surface. . Furthermore, a collet bush according to an embodiment of the present invention is a collet bush inserted into a concentric collet attached to a tool drive device for positioning a handheld tool drive device, which holds a tool and rotates and feeds it and has a chip collection function, onto a workpiece. This collet bush has a tapered cylindrical outer surface for expanding the concentric collet, a cylindrical inner surface that forms a first through hole for sliding the tool, and a passage for taking in dust collection air into the inside of the collet bush. A second through hole is formed between the outer surface and the inner surface as the passage for taking in dust collection air, such that the central axis of the second through hole is parallel to the central axis of the first through hole.

[0011] Further, a tool driving device according to an embodiment of the present invention includes the above-described collet bush and the concentric collet. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [Figure 1] A front view showing the configuration of a tool driving device having a collet bush according to a first embodiment of the present invention. [Figure 2] An exploded perspective view showing a structural example of the collet bush and the concentric collet shown in Fig. 1. [Figure 3] A view showing an example in which a housing of the tool driving device is positioned on a workpiece by the concentric collet shown in Fig. 1. [Figure 4] A longitudinal sectional view showing the detailed structure of the collet bush shown in Fig. 1. [Figure 5] A left side view of the collet bush shown in Fig. 4. [Figure 6] A right side view of the collet bush shown in Fig. 4. [Figure 7] A longitudinal sectional view showing a structural example of a collet bush according to a second embodiment of the present invention. [Figure 8] A left side view of the collet bush shown in Fig. 7. [Figure 9] A top view of the collet bush shown in Fig. 7. [Figure 10] An enlarged partial longitudinal sectional view showing a structural example of a collet bush according to a third embodiment of the present invention. [Figure 11] A partial left side view of the collet bush shown in Fig. 10. [Figure 12] A front view showing a configuration example of a collet bush according to a fourth embodiment of the present invention. [Figure 13] A left side view of the collet bush shown in Fig. 12. [Figure 14] Front view showing a configuration example of a collet bush according to a fifth embodiment of the present invention. [Figure 15] Left side view of the collet bush shown in FIG. 14. MODE FOR CARRYING OUT THE INVENTION

[0013] A collet bush and a tool driving device according to embodiments of the present invention will be described with reference to the accompanying drawings.

[0014] (First Embodiment) (Configuration and Function) FIG. 1 is a front view showing the configuration of a tool driving device having a collet bush according to a first embodiment of the present invention.

[0015] The tool driving device 1 is a hand-held device with a cutting chip dust suction function that holds a hole machining tool T such as a drill or a reamer and rotates and feeds the tool. For this reason, the tool driving device 1 includes a dust suction port 7 in addition to a holder 2 that holds the tool T, a motor 3 that rotates the holder 2, a spindle 4 that transmits the rotational torque of the motor 3 to the holder 2 and the tool T, a feed mechanism 5 that feeds out the tool T, and a housing 6 that houses the motor 3. A dust collector is connected to the dust suction port 7 via a hose or the like, and air for sucking cutting chips can be flowed by suction.

[0016] The dust suction port 7 may be formed as a part of the housing 6 or may be connected to the housing 6. Further, the housing 6 is provided with a grip 8 for a user to hold and a switch 9 for the user to manually control the motor 3.

[0017] The motor 3 may be of any of pneumatic, electric, and hydraulic types, and a gear may be connected between the motor 3 and the spindle 4 to change the rotation speed. When a gear is connected to the motor 3, the output shaft of the motor 3 and the rotation shaft of the spindle 4 may be parallel or non-parallel to each other.

[0018] The feed mechanism 5 is a device that reciprocates the holder 2 and the spindle 4 in the direction of the tool axis AX. The feed mechanism 5 can be composed of any mechanical element that moves the holder 2 and the spindle 4 linearly, such as a cylinder, a ball screw, or a gear such as a rack and pinion. A pneumatic, electric, or hydraulic motor can be used as the power source for the feed mechanism 5. Alternatively, the motor 3 that rotates the holder 2 may also be the power source for the feed mechanism 5. In other words, the rotational movement and the feed movement of the tool T may be performed by separate motors, or by a common motor.

[0019] A collet bush 10 and a concentric collet 11 can be detachably attached to the tip of the housing 6 for positioning the housing 6 of the tool drive device 1 with respect to the workpiece W to be drilled. The part provided at the tip of the housing 6 is also called a nosepiece, and the positioning bush provided as part of the nosepiece is also called a bushing tip. Therefore, the collet bush 10 can also be called a bushing tip. On the other hand, the concentric collet 11 is a general-purpose collet with a centering function.

[0020] Figure 2 is an exploded perspective view showing an example of the structure of the collet bush 10 and concentric collet 11 shown in Figure 1, and Figure 3 is a diagram showing an example in which the housing 6 of the tool drive device 1 is positioned on the workpiece W using the concentric collet 11 shown in Figure 1.

[0021] As shown in the figure, the concentric collet 11 has a cylindrical structure with multiple slits whose length is aligned with the central axis of the concentric collet 11 and which do not reach either the front end face or the rear end face, and the inner through hole is tapered so that the inner diameter gradually decreases towards the front. On the other hand, the collet bush 10 is tapered so that the outer diameter gradually decreases towards the front.

[0022] Therefore, when the concentric collet 11 is inserted into the positioning hole J2 provided in the drilling jig J, such as the drilling plate J1 fixed to the workpiece W, and the tapered collet bush 10 provided as a nosepiece on the tool drive device 1 is inserted inside the concentric collet 11, the concentric collet 11 expands in diameter, allowing the tool drive device 1 to be positioned and fixed to the drilling jig J. In other words, when the concentric collet 11 placed over the collet bush 10 is pulled towards the rear end, the diameter of the concentric collet 11 expands, allowing the concentric collet 11 to be locked to the drilling jig J, such as the drilling plate J1.

[0023] In the illustrated example, a drilling plate J1 is set on a workpiece W with a shim J3 in between. Positioning pins J4 are inserted into the reference hole in the workpiece W and the reference hole in the drilling plate J1 so that the positioning hole J2 in the drilling plate J1 becomes the hole drilling position. In addition to drilling, hole drilling may also be performed by finishing the hole with a reamer.

[0024] A flange-like portion is provided on the rear end of the collet bush 10 and the concentric collet 11. Therefore, by allowing the tips of the collet bush 10 and the concentric collet 11 to protrude from a through hole formed at the front of the housing 6, while positioning the flange-like portions of the collet bush 10 and the concentric collet 11 inside the housing 6, the collet bush 10 and the concentric collet 11 can be connected to the housing 6.

[0025] A connecting structure such as a screw can be provided at the tip of the housing 6 and at the flange-like portion formed on the rear end of the collet bush 10 and concentric collet 11 so that the collet bush 10 and concentric collet 11 can be fixed to the housing 6. In the illustrated example, a detachable cap 12 is provided at the tip of the housing 6, and the flange-like portions of the collet bush 10 and concentric collet 11 are positioned inside the cap 12, while the tips of the collet bush 10 and concentric collet 11 can protrude from the through hole in the cap 12. Therefore, by removing the cap 12, in addition to attaching and detaching the collet bush 10 and concentric collet 11 to the housing 6, the tool T can also be attached and detached to the holder 2.

[0026] The inside of the collet bush 10 is used for passing the tool T through, and also serves as an air passage when chips are being sucked up. That is, when a dust collector connected to the dust collection port 7 by a hose or the like is activated, an airflow for dust collection is formed from the inside of the collet bush 10 through the inside of the housing 6 toward the dust collection port 7. However, in addition to the through hole for sliding the tool T, an air passage for dust collection is formed inside the collet bush 10.

[0027] Next, we will describe a detailed structural example of the collet bush 10.

[0028] Figure 4 is a longitudinal cross-sectional view showing the detailed structure of the collet bush 10 shown in Figure 1, Figure 5 is a left side view of the collet bush 10 shown in Figure 4, and Figure 6 is a right side view of the collet bush 10 shown in Figure 4.

[0029] As shown in Figures 4 to 6, the collet bush 10 has a cylindrical insertion portion 20 that protrudes from the housing 6 and is inserted into the concentric collet 11, and a cylindrical flange portion 21 that is positioned inside the housing 6 and fixed to the housing 6. The insertion portion 20 also has a tapered cylindrical outer surface 22 for expanding the concentric collet 11 and a cylindrical inner surface 26 that forms a through hole 23 for sliding the tool T.

[0030] The diameter of the outer surface 22 of the insertion portion 20 gradually decreases towards the tip, so the outer surface 22 of the insertion portion 20 has a curved surface similar to the side surface of a frustocone. On the other hand, the inner surface 26 of the insertion portion 20 for sliding the tool T has a constant diameter so as to slide with the tool T. For this reason, the inner surface 26 of the insertion portion 20 for sliding the tool T has a cylindrical shape, that is, a curved surface similar to the side surface of a cylinder.

[0031] Furthermore, the diameter of the flange portion 21 is larger than the maximum diameter of the outer surface 22 of the insertion portion 20. Therefore, only the flange portion 21 can be secured inside the housing 6. As described above, a connecting structure such as a female or male screw can be formed on the inner or outer surface of the flange portion 21 to match the connecting structure on the housing 6 side, so that the collet bush 10 can be fixed to the cap 12 of the housing 6.

[0032] Furthermore, an air through-hole 25 is formed inside the collet bush 10 between the outer surface 22 and the inner surface 26 of the insertion portion 20, serving as a passage for drawing dust-collecting air into the collet bush 10. In principle, the air through-hole 25 may be a single hole, but forming multiple through-holes 25 is rational from the viewpoint of ensuring sufficient dust collection power.

[0033] In the illustrated example, the inner surface 26 that slides with the tool T is formed only on a portion of the tip side in the longitudinal direction of the collet bush 10, and the diameter of the second inner surface 26 at the rear end side of the first inner surface 26 that slides with the tool T is larger than the diameter of the first inner surface 26 that slides with the tool T. In other words, a stepped through hole is formed inside the insertion portion 20 of the collet bush 10. This reduces interference between the shank, which has a diameter larger than the tool diameter of the tool T, and the collet bush 10 when the tool T is fed out while sliding the tool T against the first inner surface 26 of the insertion portion 20.

[0034] Therefore, the air through-holes 25 are formed between the first inner surface 26 of the insertion portion 20 that slides with the tool T and the outer surface 22 of the insertion portion 20. That is, one end of each through-hole 25 opens at the end face on the tip side of the collet bush 10, and the other end of each through-hole 25 opens at an annular stepped surface formed between the first inner surface 26 with a smaller diameter and the second inner surface 26 with a larger diameter. As a result, the central axis of each through-hole 25 that forms the air passage is parallel to the central axis of the through-hole 23 that slides with the tool T.

[0035] Alternatively, a step could be formed on the end face at the tip of the collet bush 10, causing each through-hole 25 to open inside the insertion portion 20. However, as shown in the figure, opening the holes at the end face at the tip of the collet bush 10 allows for the diameter of each through-hole 25 to be made as large as possible while ensuring the plate thickness necessary to guarantee the strength of the collet bush 10. This improves the dust collection effect.

[0036] In particular, the length of the insertion portion 20 of the collet bush 10 is longer than the length of the concentric collet 11, similar to a typical conventional collet bush. Therefore, when the insertion portion 20 of the collet bush 10 is inserted into the concentric collet 11, the tip of the insertion portion 20 protrudes from the concentric collet 11. For this reason, as illustrated in Figure 3, if the end face on the tip side of the collet bush 10 is not in contact with the workpiece W from the viewpoint of avoiding damage to the workpiece W, a sufficient flow rate of dust-collecting air can be drawn in through each through-hole 25 that opens at the end face on the tip side of the collet bush 10.

[0037] The collet bush 10 described above has a dedicated through-hole 25 formed inside, separate from the through-hole 23 for sliding with the tool T, to serve as a passage for dust-collecting air. The tool drive device 1 is equipped with such a collet bush 10 and a concentric collet 11.

[0038] (effect) Therefore, with the collet bush 10 and tool drive device 1, it is possible to position the tool T relative to the workpiece W using the concentric collet 11 while simultaneously preventing tool T runout and ensuring sufficient chip collection. Specifically, by sliding the tool T against the first inner surface 26 of the insertion portion 20 of the collet bush 10, tool T runout is prevented, while the dust collection effect can be maintained by flowing a sufficient amount of air through the through hole 25. As a result, chip clogging can be avoided while ensuring the accuracy of hole machining. In addition, since a sufficient airflow for dust collection can be ensured, the tool T can also be air-cooled.

[0039] In particular, when machining holes in fiber-reinforced plastics (FRP), such as glass fiber reinforced plastics (GFRP) and carbon fiber reinforced plastics (CFRP), or in laminated materials of FRP and metals such as aluminum, ensuring hole machining accuracy and avoiding chip clogging are crucial. Therefore, using the collet bush 10 and tool drive device 1 described above in these hole machining processes can easily satisfy these requirements.

[0040] (Second embodiment) Figure 7 is a longitudinal cross-sectional view showing an example of the structure of a collet bush according to the second embodiment of the present invention, Figure 8 is a left side view of the collet bush shown in Figure 7, and Figure 9 is a top view of the collet bush shown in Figure 7.

[0041] The collet bush 10A in the second embodiment shown in Figures 7 to 9 differs from the collet bush 10 in the first embodiment in that a through hole 30 is formed at the tip end, with the radial direction of the collet bush 10A as the central axis. The other configurations and operations of the collet bush 10A in the second embodiment are substantially the same as those of the collet bush 10 in the first embodiment, so the same or corresponding components are denoted by the same reference numerals and their descriptions are omitted.

[0042] As shown in Figures 7 to 9, a through-hole 30, whose central axis is in the radial direction of the collet bush 10A, can be formed as a passage for dust-collecting air, intersecting with a through-hole 25 whose central axis is in the longitudinal direction of the collet bush 10A. In this case, as illustrated in Figures 7 and 8, it is reasonable to make the central axis of the through-hole 25 extending in the longitudinal direction of the collet bush 10A intersect with the central axis of the through-hole 30 extending in the radial direction of the collet bush 10A.

[0043] As in the second embodiment, by adding a radially extending through-hole 30 in the collet bush 10A as a passage for dust-collecting air, it becomes possible to take in a sufficient flow rate of air when machining holes with the end face at the tip of the collet bush 10A in contact with or close to the workpiece W. Therefore, the dust-collecting effect can be maintained.

[0044] (Third embodiment) Figure 10 is an enlarged partial longitudinal cross-sectional view showing an example of the structure of a collet bush according to the third embodiment of the present invention, and Figure 11 is a partial left side view of the collet bush shown in Figure 10.

[0045] The collet bush 10B in the third embodiment shown in Figures 10 and 11 differs from the collet bush 10 in the first embodiment in that a chamfer 40 is formed at the end of the through hole 25 that extends in the longitudinal direction of the collet bush 10B. Since the other configurations and operations of the collet bush 10B in the third embodiment are substantially the same as those of the collet bush 10 in the first embodiment, only the end of the through hole 25 is shown, and the same or corresponding components are denoted by the same reference numerals and their descriptions are omitted.

[0046] As illustrated in Figures 10 and 11, a chamfer 40, such as a C-chamfer or R-chamfer, may be formed on the through hole 25 that opens at the end face of the collet bush 10B on the tip side. By forming a chamfer 40 on the end of the through hole 25, the entrance to the air passage for dust collection can be widened while ensuring the plate thickness at the tip side of the collet bush 10B. Specifically, the opening end of the through hole 25 that serves as the air entrance becomes a frustoconical space.

[0047] Therefore, according to the third embodiment, when hole machining is performed with the end face of the collet bush 10B at the tip side close to the workpiece W, a flow of dust-collecting air toward the through hole 25 can be formed.

[0048] (Fourth embodiment) Figure 12 is a front view showing an example of the configuration of a collet bush according to the fourth embodiment of the present invention, and Figure 13 is a left side view of the collet bush shown in Figure 12.

[0049] The collet bush 10C in the fourth embodiment shown in Figures 12 and 13 differs from the collet bush 10 in the first embodiment in that the shape of its tip is serrated 50. Since the other configurations and operations of the collet bush 10C in the fourth embodiment are substantially the same as those of the collet bush 10 in the first embodiment, the same or corresponding components are denoted by the same reference numerals and their descriptions are omitted.

[0050] As illustrated in Figures 12 and 13, if the annular tip of the collet bush 10C is made into a jagged shape 50, a gap will be created between the collet bush 10C and the workpiece W when the tip of the collet bush 10C is in contact with or close to the workpiece W. In other words, no end face is formed at the tip of the collet bush 10C with the direction of the central axis of the collet bush 10C as the normal direction. When the tip of the collet bush 10C is brought into contact with the workpiece W, the contact will not be surface contact but rather intermittent line contact in the circumferential direction of the collet bush 10C.

[0051] Therefore, when the tip of the collet bush 10C is brought close to the workpiece W, and even when the tip of the collet bush 10C is in contact with the workpiece W, it is possible to take in a sufficient flow rate of air from the gap created between the collet bush 10C and the workpiece W. For this reason, as illustrated in Figures 12 and 13, the spacing between the peaks and valleys of the jagged shape 50 can be determined so that each through hole 25 extending in the longitudinal direction of the collet bush 10C opens at a valley of the jagged shape 50. In this case, when the tip of the collet bush 10C is in contact with or close to the workpiece W, a sufficient flow rate of dust-collecting air can be introduced into the through hole 25 from the gap created between the collet bush 10C and the workpiece W.

[0052] According to the fourth embodiment described above, the recesses in the valleys of the jagged shape 50 formed at the tip of the collet bush 10C can be used as air passages for dust collection. Therefore, even when the tip of the collet bush 10C is in contact with or close to the workpiece W, the dust collection effect can be maintained.

[0053] (Fifth embodiment) Figure 14 is a front view showing an example of the configuration of a collet bush according to the fifth embodiment of the present invention, and Figure 15 is a left side view of the collet bush shown in Figure 14.

[0054] The collet bush 10D in the fifth embodiment shown in Figures 14 and 15 differs from the collet bush 10 in the first embodiment in that a cushioning material 60 with irregularities is attached to the annular end face at the tip. The other configurations and operations of the collet bush 10D in the fifth embodiment are substantially the same as those of the collet bush 10 in the first embodiment, so the same or corresponding components are denoted by the same reference numerals and their descriptions are omitted.

[0055] As illustrated in Figures 14 and 15, a cushioning material 60 having irregularities in the longitudinal and central axis directions of the collet bush 10D can be bonded to the annular end face at the tip of the collet bush 10D using an adhesive or the like. In this case, the depressions in the irregularities of the cushioning material 60 can be used as air passages for dust collection.

[0056] Therefore, as illustrated in Figures 14 and 15, the spacing of the irregularities can be determined so that each through-hole 25 extending in the longitudinal direction of the collet bush 10D opens near the recess of the irregularities in the cushioning material 60. In this way, when the tip of the collet bush 10D is in contact with or close to the workpiece W, a sufficient flow rate of dust-collecting air can be introduced into the through-hole 25 from the gap created between the cushioning material 60 and the workpiece W.

[0057] Examples of materials for the cushioning material 60 include resins such as polyacetal copolymer, porous aluminum, or elastic materials such as rubber. Furthermore, the unevenness of the cushioning material 60 is not limited to the zigzag shape exemplified in Figures 14 and 15, but may also be a jagged shape with sharp tips as shown in Figures 12 and 13, or a shape with rounded edges on the peaks of the jagged shape, or a smooth wave shape.

[0058] According to the fifth embodiment described above, not only can the dust collection effect be maintained when the tip of the collet bush 10D is in contact with or close to the workpiece W, but since a cushioning material 60 is provided at the tip, damage to the workpiece W can be prevented when the tip of the collet bush 10D is in contact with the workpiece W.

[0059] (Other embodiments) Although specific embodiments have been described above, these embodiments are merely examples and do not limit the scope of the invention. The novel methods and apparatus described herein can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications can be made in the forms of methods and apparatus described herein, without departing from the spirit of the invention. The attached claims and equivalents include such various forms and modifications as being encompassed within the scope and spirit of the invention.

[0060] For example, the embodiments may be combined. Specifically, if the second and third embodiments are combined, a chamfer 40 can be formed at the end of the through hole 25 that extends in the longitudinal direction of the collet bush 10A in the second embodiment. [Explanation of Symbols]

[0061] 1. Tool drive device 2 holders 3 motors 4 spindles 5 Feed mechanism 6 cabinets 7. Dust collection port 8 grips 9 switches 10, 10A, 10B, 10C, 10D Collet Bushings 11 Concentric Collet 12 caps 20 Insertion section 21 Flange 22 Exterior 23 Through hole 24 Inner self 25 Through holes 26 Inner self 30 Through holes 40 Chamfer 50 Jagged shape 60 Cushioning material AX tool axis J Drilling jig J1 perforated plate J2 Positioning hole J3 Sim J4 Positioning pin T-tool Double job

Claims

1. A collet bush is inserted into a concentric collet attached to a handheld tool drive device that holds, rotates, and feeds a tool, and has a chip collection function, in order to position the tool drive device on a workpiece, The tapered cylindrical outer surface for widening the concentric collet, A cylindrical inner surface having a first through hole for sliding the tool, a first inner surface formed on the tip side of the collet bush, and a second inner surface formed on the rear end side of the collet bush and having a larger diameter than the first inner surface, The collet bush has a passage for taking in air for dust collection, It has, A collet bush having a second through-hole formed between its outer surface and the first inner surface, which serves as the passage for taking in the dust-collecting air. The second through-hole is formed between the outer surface and the first inner surface, with one end opening at the end face on the tip side of the collet bush and the other end opening at an annular stepped surface formed between the first inner surface and the second inner surface.

2. A collet bush inserted into a concentric collet attached to a tool drive device for positioning a handheld tool drive device, which holds a tool and rotates and feeds it and has a chip collection function, on a workpiece, The tapered cylindrical outer surface for widening the concentric collet, A cylindrical inner surface forming a first through hole for sliding the tool, The collet bush has a passage for taking in air for dust collection, It has, A collet bush having a second through-hole formed between the outer surface and the inner surface as a passage for taking in the air for dust collection, such that the central axis of the second through-hole is parallel to the central axis of the first through-hole.

3. The collet bush according to claim 1, wherein the air passage is widened by forming a chamfer at the end of the second through hole on the tip side of the collet bush.

4. The collet bush according to claim 1, wherein a cushioning material having irregularities in the direction of the central axis of the collet bush is provided on the annular end face at the tip side of the collet bush, and the recesses of the irregularities are further used as flow channels.

5. A collet bush according to any one of claims 1 to 4, The aforementioned concentric collet and, A tool drive device having the following features.

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