Tool driving device and manufacturing method of a perforated member
By introducing a vibration mechanism and a ball bearing sliding surface design into the tool drive device, the problems of chip clogging and breakage of drill bits when machining difficult-to-machine materials are solved, and stable and efficient piercing machining is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUBARU CORP
- Filing Date
- 2022-02-14
- Publication Date
- 2026-07-21
AI Technical Summary
Existing vibration mechanisms can easily cause chips to clog the drill bit grooves or damage the drill bit during the drilling process, especially when machining difficult-to-machine materials such as titanium and composite materials, which affects the machining quality and efficiency.
A tool driving device is adopted, which uses a vibration mechanism between the drill chuck and the frame to make the drill bit and the drill chuck move back and forth periodically along the tool axis. Multiple balls roll on a specific concave-convex sliding surface to achieve low-speed moving away from and low-speed approaching of the drill bit to the workpiece, thus avoiding chip clogging and drill bit damage.
It effectively prevents chip clogging, ensures stable operation of the drill bit, avoids damage from collisions between the drill bit and the workpiece, and improves processing quality and efficiency, especially in maintaining hole diameter accuracy when processing titanium and composite materials.
Smart Images
Figure CN115070087B_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present invention relate to a tool driving device and a method for manufacturing a pierced part. Background Technology
[0002] When drilling, it is important to cut and remove the chips to prevent them from clogging the drill bit's grooves. Therefore, mechanisms have been proposed to crush the chips by intentionally vibrating the drill bit along the tool axis (see, for example, Patent Documents 1 and 2).
[0003] Specifically, by moving multiple balls held by a cage into and out of a recess that rotates together with the spindle, the spindle can be made to vibrate in the direction of rotation. That is, when each ball enters the recess, the drill bit and the spindle move together away from the object being drilled (workpiece), and when each ball exits the recess, the drill bit and the spindle move together towards the workpiece. Thus, the spindle and drill bit can be made to periodically reciprocate along the tool axis with a certain amplitude.
[0004] Existing technical documents
[0005] Patent documents
[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-117852
[0007] Patent Document 2: Japanese Patent Application Publication No. 2003-266426 Summary of the Invention
[0008] The problem that the invention aims to solve
[0009] However, in existing vibration mechanisms, the drill bit temporarily disengages from the workpiece as the balls enter the recess, and then suddenly pushes the drill bit towards the workpiece as the balls exit the recess. Therefore, if the user uses a handheld tool drive for piercing, and then relaxes the force while holding the tool drive, the drill bit will be pushed back by the piercing reaction force. Consequently, piercing cannot immediately resume after the balls exit the recess.
[0010] Conversely, if the user holds the handheld tool drive with force, the drill bit collides with the workpiece as the balls emerge from the recesses. Therefore, if the workpiece has a high strength relative to the drill bit, the drill bit may break. As a specific example, titanium is stronger than typical drill bit materials; therefore, when piercing titanium, the drill bit may break if existing vibration mechanisms are used.
[0011] Therefore, existing vibration mechanisms cannot be used when drilling difficult-to-machine materials such as titanium is possible. Consequently, if a tool drive without a vibration mechanism is used to drill not only difficult-to-machine materials like titanium but also metals like aluminum, the continuously ejected metal chips cannot be cut off, potentially clogging the drill bit's flutes. If the chips clog the drill bit's flutes, it can lead to drill bit rotation stopping or damage to the workpiece.
[0012] In particular, when perforating fiber-reinforced plastics (FRP), also known as glass fiber reinforced plastics (GFRP) or carbon fiber reinforced plastics (CFRP), and metals from the FRP side, if perforation on the metal side begins after perforation on the FRP side is completed, metal chips may clog the drill bit, making it difficult to continue perforation; or the inner surface of the FRP may be cut with a drill bit that clogs the metal chips, resulting in an undesirable situation where the FRP hole diameter becomes too large.
[0013] Therefore, the purpose of this invention is to stably pierce the workpiece while preventing chips from clogging the drill bit and the drill bit from breaking.
[0014] Technical solutions for solving the problem
[0015] The tool drive device according to an embodiment of the present invention includes: a drill chuck that holds a drill bit; a motor that rotates the drill chuck; a frame that houses the motor; and a vibration mechanism that periodically reciprocates the drill chuck along the tool axis direction relative to the frame during the rotation of the drill chuck, and moves the drill chuck away from the frame at a speed less than the speed at which the drill chuck approaches the frame.
[0016] In addition, in the method for manufacturing a pierced part according to the embodiments of the present invention, the drill bit is held by the tool driving device described above, and the drill bit rotated by the tool driving device is used to pierce the piercing object, thereby manufacturing the pierced part. Attached Figure Description
[0017] Figure 1 This is a partial cross-sectional view showing the structure of the tool driving device according to the first embodiment of the present invention.
[0018] Figure 2 It means Figure 1 The enlarged longitudinal sectional view of the vibration mechanism shown.
[0019] Figure 3Is Figure 2 The left-side view shows the state of the vibrating mechanism with a retaining ring housing the balls.
[0020] Figure 4 yes Figure 2 The vibrating mechanism shown has a right-side view of a rotating ring.
[0021] Figure 5 yes Figure 4 The diagram shows the cross-section of the rotating ring at position A-A unfolded into a plane.
[0022] Figure 6 It is by... Figure 5 The unfolded sectional view of the rotating ring shown is magnified only along the thickness direction of the rotating ring to emphasize the concave and convex features.
[0023] Figure 7 This indicates that it will be set in Figure 2 The right-side view shows an example where the slope of the bottom surface of the groove of the rotating ring is limited to the valley side of each step.
[0024] Figure 8 It is Figure 7 The diagram shows the cross-section of the rotating ring at position B-B unfolded into a plane.
[0025] Figure 9 It is by... Figure 8 The unfolded sectional view of the rotating ring shown is magnified only along the thickness direction of the rotating ring to emphasize the concave and convex features.
[0026] Figure 10 This is a partial cross-sectional view showing the structure of the tool driving device according to the second embodiment of the present invention.
[0027] Figure 11 yes Figure 10 The enlarged longitudinal sectional view of the vibration mechanism shown.
[0028] Figure 12 It is by Figure 11 The left-hand view shown shows the state of multiple balls held by the ball cage.
[0029] Figure 13 yes Figure 11 The right-side view of the rotating ring shown. Detailed Implementation
[0030] The tool driving device and the manufacturing method of the pierced part according to embodiments of the present invention will be described with reference to the accompanying drawings.
[0031] (First Implementation)
[0032] (Composition and Function)
[0033] Figure 1This is a partial cross-sectional view showing the structure of the tool driving device according to the first embodiment of the present invention.
[0034] The tool drive device 1 is a device that holds the drill bit T and drives it to rotate in order to pierce the workpiece W that is to be pierced. In addition, the piercing tool held by the tool drive device 1 is sometimes called a drilling bit, and the tool drive device 1 that rotates the drilling bit is itself called a drill bit.
[0035] The tool drive unit 1 can be equipped with not only a rotation mechanism for the drill bit T, but also a feed mechanism. That is, the drill bit T can be fed toward the workpiece W by the user pushing out the tool drive unit 1 itself, or the drill bit T can be fed toward the workpiece W automatically or semi-automatically by the tool feed mechanism.
[0036] The tool drive unit 1 can consist of a drill chuck 2 that holds the drill bit T, a motor 3 that rotates the drill chuck 2, and a frame 4 that houses the motor 3. The motor 3 can be electric, hydraulic, pneumatic, or any other type. The output shaft of the motor 3 can function as a spindle 5 that rotates the drill chuck 2 together with the drill bit T. In other words, the output shaft of the motor 3 and the spindle 5 can be integrated. Alternatively, the output shaft of the motor 3 and the spindle 5 can be arranged parallel to each other and torque can be transmitted via gears or the like.
[0037] When the tool drive unit 1 is designed to be handheld, a handle 6 is provided on the frame 4 for the user to grip. A switch 7 for operating the motor 3 can be provided on or near the handle 6.
[0038] Furthermore, a vibration mechanism 8 is provided on the tool drive unit 1 to periodically reciprocate the drill bit T, drill chuck 2, and spindle 5 relative to the frame 4 during rotation. When the spindle 5 reciprocates along the tool axis AX, if it is a typical motor 3, the motor 3 also reciprocates along the tool axis AX. Therefore, for example, a gap can be provided between the motor 3, which is normally housed without gaps in the motor housing 3A, and the motor housing 3A, allowing the motor 3 to reciprocate along the tool axis AX.
[0039] If the vibration mechanism 8 is used to periodically move the drill bit T and the drill chuck 2 back and forth along the tool axis AX by a distance that is extremely small compared to the feed rate, specifically 0.01 mm to 0.15 mm, then the chips that are continuously discharged, such as metal chips, can be cut off. In other words, if the drill bit T and the drill chuck 2 are vibrated with an amplitude of 0.01 mm to 0.15 mm, the chips can be cut off. As a result, chip clogging of the drill bit T can be prevented.
[0040] This is because if the drill bit T and drill chuck 2 move closer to the frame 4, the cutting drill bit T temporarily moves away from the workpiece W, and the drilling is interrupted. Then, if feed is given to the drill bit T and drill chuck 2, the cutting can resume. This process of intermittently drilling while removing chips by alternating between cutting and interruption is also called peck machining, peck drilling, or step machining.
[0041] In addition, if the vibration amplitude is too small, specifically if the vibration amplitude is less than 0.01 mm, the chip cutting effect is insufficient; if the vibration amplitude is too large, specifically if the vibration amplitude exceeds 0.15 mm, it is difficult for the user to hold the tool and drive the device 1 by hand.
[0042] In particular, the vibration mechanism 8 is configured to move the drill bit T and drill chuck 2 away from the frame 4 at a speed lower than the speed at which the drill bit T and drill chuck 2 approach the frame 4. That is, the drill bit T vibrates at different speeds between the forward and reverse paths. More specifically, the movement of the drill bit T and drill chuck 2 toward the frame 4 to temporarily remove the drill bit T from the workpiece W and interrupt the drilling process is performed instantaneously, while the movement of the drill bit T and drill chuck 2 away from the frame 4 to bring the temporarily removed drill bit T and drill chuck 2 back toward the workpiece W is performed at the lowest possible speed.
[0043] Therefore, because the drill bit T instantly leaves the workpiece W, the chips can be reliably cut off by interrupting the piercing process. Furthermore, when piercing resumes, the drill bit T moves towards the workpiece W at a low speed, thus preventing damage from collision. Additionally, because the drill bit T moves towards the workpiece W at a low speed immediately after piercing resumes, the rate of increase in piercing reaction force is reduced, preventing the user from being pushed back due to a sudden increase in piercing reaction force.
[0044] The vibration mechanism 8 can be composed of a sliding surface 9 with concave and convex surfaces corresponding to the moving speed of the drill bit T and the drill chuck 2, and a plurality of balls 10 rolling on the sliding surface 9 during the rotation of the drill chuck 2. Alternatively, the vibration mechanism 8 can be constructed by replacing the balls 10 with a rotating body such as a roller, wheel, or a disc-shaped component with smooth, lubricating protrusions sliding on the sliding surface 9; however, the following explanation will use the most practical ball 10 as an example.
[0045] Figure 2 yes Figure 1 The enlarged longitudinal sectional view of the vibration mechanism 8 shown is shown. Figure 3 It stores the ball bearing 10 in Figure 2The left-side view of the vibration mechanism 8 shown depicts the state of the fixed ring 11. Figure 4 yes Figure 2 The vibration mechanism 8 shown is a right-side view of the rotating ring 12. Figure 5 It is Figure 4 The diagram shows the cross-section of position AA of the rotating ring 12 unfolded into a plane. Figure 6 It is by... Figure 5 The unfolded sectional view of the rotating ring 12 shown is magnified only along the thickness direction of the rotating ring 12 to emphasize the concave and convex shapes.
[0046] Multiple balls 10 are rotatably arranged at equal intervals on the same circle between the drill chuck 2 and the frame 4. During the rotation of the drill chuck 2, the sliding surface 9 of the multiple balls 10 rolling and contacting each other can be directly or indirectly provided on one of the drill chuck 2 and the frame 4.
[0047] Therefore, in the illustrated example, a retaining ring 11 with a central through-hole for passing through the spindle 5 and a rotating ring 12 with a central through-hole for passing through the spindle 5 are separated by a gap and fixed to the frame 4 and the drill chuck 2, respectively. Furthermore, an internal thread is formed on the inner surface of the through-hole of the rotating ring 12, and an external thread is formed on the surface of the spindle 5, which also allows the rotating ring 12 to be fixed to the spindle 5. Thus, the retaining ring 11 does not rotate relative to the frame 4, but the rotating ring 12 rotates together with the drill chuck 2 and the spindle 5 relative to the frame 4 and the retaining ring 11.
[0048] Furthermore, a plurality of spherical recesses arranged at equal intervals on the same circle on the retaining ring 11 respectively rotatably accommodate portions of a plurality of balls 10. Therefore, the plurality of balls 10 rotatably relative to the frame 4 that fixes the retaining ring 11 in a relatively fixed position. In addition, the retaining ring 11 functions as an annular ball retainer that rotatably holds portions of the plurality of balls 10.
[0049] On the other hand, a sliding surface 9 with concave and convex shapes is formed on the rotating ring 12. The shape of the sliding surface 9 is such that it has multiple steps 9A at equal intervals, so that multiple balls 10 fall simultaneously during the forward rotation of the drill chuck 2, and the shape changes smoothly from each step 9A toward the adjacent step 9A without creating steps that would cause the multiple balls 10 to climb during the forward rotation of the drill chuck 2. That is, when the drill bit T and the drill chuck 2 are rotated forward by the forward rotation of the motor 3, as Figure 5 and Figure 6 For example, multiple balls 10 fall simultaneously on step 9A of the sliding surface 9 without climbing any steps, in order to determine the uneven shape of the sliding surface 9 by rolling and climbing towards the next step 9A on a smooth inclined surface.
[0050] Therefore, when the drill bit T and drill chuck 2 are rotated clockwise for drilling, the sliding surface 9 of the rotating ring 12 fixed to the drill chuck 2 rotates relative to the plurality of balls 10. As a result, the plurality of balls 10 fall simultaneously from the step 9A of the sliding surface 9 due to the drilling reaction force from the workpiece W. Consequently, the drill bit T and drill chuck 2 momentarily and temporarily move away from the workpiece W and approach the frame 4. Thus, the drilling is interrupted, and the chips are cut off.
[0051] Conversely, after the multiple balls 10 fall from a high position to a low position on step 9A, the drill bit T and drill chuck 2 are fed, generating a perforation reaction force from the workpiece W again. Therefore, each ball 10 rolls while contacting the sliding surface 9, whose position changes smoothly, and reaches the high position of the adjacent step 9A. Thus, the drill bit T and drill chuck 2 do not collide with the workpiece W at high speed, and the perforation reaction force from the workpiece W does not increase locally. As a result, damage to the drill bit T is avoided, and the user is not pushed back by the perforation reaction force from the workpiece W, allowing for stable continuation of perforation.
[0052] The sliding surface 9, as shown in the figure, can be formed as the inner surface of a groove 9B whose length direction is set as the rotation direction including the forward and reverse rotation directions of the drill chuck 2. In this case, the groove 9B becomes a sloping groove whose depth gradually decreases from each step 9A formed on the inner surface of the groove 9B toward the adjacent step 9A.
[0053] Normally, clockwise rotation is the correct direction of rotation; therefore, the groove 9B of the rotating ring 12 rotates clockwise relative to each ball 10 along with the drill chuck 2. Consequently, each ball 10 moves counterclockwise relative to the groove 9B of the rotating ring 12. Therefore, as... Figures 4-6 For example, each step 9A is positioned in the groove 9B in the direction in which each ball 10 falls as it rotates counterclockwise relative to the annular groove 9B. In other words, there exists a situation where each ball 10 rotates counterclockwise relative to the annular groove 9B (in... Figure 5 and Figure 6 In the unfolded diagram, when each ball 10 moves to the right relative to the groove 9B, it crosses the ridge line and falls onto step 9A, but the step that climbs onto the ridge line does not exist in the groove 9B. In addition, when performing a special piercing process by rotating the drill bit T counterclockwise, it is only necessary to reverse the direction of step 9A and the ramp.
[0054] Alternatively, instead of serving as the inner surface of the groove 9B, the sliding surface 9 can be formed by a conical surface having multiple steps 9A in the same direction as the rotation direction of the drill chuck 2, or by a wave-shaped surface having multiple steps 9A in the same direction as the rotation direction of the drill chuck 2.
[0055] When forming groove 9B as sliding surface 9, the cross-sectional shape of groove 9B can be a V-groove or a groove with a flat bottom surface. However, as shown in the figure, if at least a portion of the cross-sectional shape of groove 9B is set to an arc with the same radius as the ball 10, so that each ball 10 is in contact with a portion of the bottom surface of groove 9B, then the ball 10 will not make point contact with groove 9B but will make line contact, thus delaying the wear of ball 10. When the cross-sectional shape of groove 9B is set to an arc, groove 9B is mostly formed by grooving using a ball end mill. Therefore, a radius chamfer can also be applied to the valley side of each step 9A.
[0056] In addition, Figure 5 and Figure 6 In the example shown, the bottom surface of groove 9B is inclined over the entire area between adjacent steps 9A. However, if the edges of the steps that the ball 10 climbs can be eliminated, the inclination of the bottom surface can also be set to a portion starting from the valley side of each step 9A, and the remaining portion facing the peak side of each adjacent step 9A is not inclined.
[0057] Figure 7 This indicates that it will be set in Figure 2 The right-side view shows an example where the slope of the bottom surface of the groove 9B of the rotating ring 12 is limited to the valley side of each step 9A. Figure 8 It is Figure 7 The diagram shown is a planar view of the cross section at position B-B of the rotating ring 12. Figure 9 It is by... Figure 8 The unfolded sectional view of the rotating ring 12 shown is magnified only along the thickness direction of the rotating ring 12 to emphasize the concave and convex shapes.
[0058] like Figures 7-9 As an example, if the edges of the steps that the ball bearings 10 climb are removed, the slope of the bottom surface of the groove 9B can be limited to the vicinity of the valley side of each step 9A. In this case, the bottom surface of the groove 9B on the peak side of each step 9A is not sloped, thus simplifying the shape of the rotating ring 12. Therefore, the manufacturing of the rotating ring 12 can also be simplified. In particular, even if the drop of each step 9A is smaller, and the range of slope of the bottom surface of the groove 9B is shortened, the edges of the steps that the ball bearings 10 climb can be removed to a negligible degree.
[0059] The sliding surface 9, formed by the inner surface of the sloping groove 9B, has multiple steps 9A at equal intervals. Therefore, if the drill bit T and the drill chuck 2 are rotated forward at a specified speed, periodic vibrations with the amplitude of the drop of the steps 9A are generated on the drill bit T and the drill chuck 2. That is, when the multiple balls 10 cross the edge of the step 9A, the movement direction of the drill bit T and the drill chuck 2 is reversed, and the drilling is interrupted.
[0060] Therefore, the drop of step 9A where the ball 10 falls can be determined from the perspective that the user can hold the tool drive device 1 by hand and obtain the chip-cutting effect, based on the desired vibration amplitude, specifically determined to be 0.01 mm to 0.15 mm as described above. Furthermore, the size of the ball 10 is not important; the amount of movement of the ball 10 in the tool axis AX direction, i.e., the drop of step 9A, is extremely important. However, reducing the size of the ball 10 has the advantage of making the vibration mechanism 8 more compact, while increasing the size of the ball 10 has the advantage of delaying the wear of the ball 10.
[0061] The number of balls 10 is preferably set to three or more, so that even if a perforation reaction force is applied from the workpiece W, the vibration of the drill bit T and the drill chuck 2 will not increase. If the number of balls 10 increases, the number of steps 9A increases accordingly, and therefore the interval between adjacent steps 9A becomes shorter. Therefore, if the number of balls 10 increases, the vibration of the drill bit T and the drill chuck 2 increases.
[0062] If the vibration frequency of drill bit T and drill chuck 2 increases, the interruption frequency of piercing increases, thus achieving the effect of finer chips. On the other hand, the cutting time per unit time decreases. Therefore, from the viewpoint of not increasing the cutting time, it is desirable to limit the number of balls 10 to the number required to finer the chips to a level that sufficiently prevents chip clogging of drill bit T. Furthermore, if piercing is performed on typical metal materials such as aluminum under typical piercing conditions such as hole diameter, depth, drill bit T rotation speed, and number of cutting edges of drill bit T, then three balls 10 are considered sufficient.
[0063] Furthermore, by making the number of steps 9A on the sliding surface 9 different from the number of balls 10, even if it is set to a multiple of the number of balls 10, the drill bit T and the drill chuck 2 can still vibrate at a specified number of vibrations. However, if the number of steps 9A is increased, the cutting time per unit time will decrease, just like if the number of balls 10 is increased. Therefore, the number of steps 9A should be set to the necessary minimum in order to obtain the chip cutting effect.
[0064] The same applies to the shape requirements of the balls 10 and the sliding surface 9, even when the sliding surface 9 is formed on the fixed ring 11 fixed to the frame 4 instead of on the rotating ring 12 fixed to the drill chuck 2. When the sliding surface 9 is formed on the fixed ring 11 fixed to the frame 4, a ball retainer can be formed by providing a spherical recess on the rotating ring 12 fixed to the drill chuck 2. In this case, the multiple balls 10 roll in a relatively fixed position relative to the drill chuck 2 with the rotating ring 12 fixed. Therefore, when the drill bit T and the drill chuck 2 are rotated clockwise, the multiple balls 10 also rotate clockwise while rolling on the sliding surface 9.
[0065] The tool drive device 1 described above uses a vibration mechanism 8 consisting of multiple balls 10 rolling on a sliding surface 9 with appropriate concave and convex shapes to cause the drill bit T and drill chuck 2 to move away from the workpiece W instantaneously, while generating periodic vibrations that slowly approach the workpiece W side.
[0066] (Effect)
[0067] According to the tool drive device 1, the drill bit T moves away from the workpiece W intermittently and periodically, resulting in finely cut chips that are easily removed. Therefore, it is possible to prevent the FRP from having excessively large hole diameters due to chip clogging of the drill bit T's grooves, thus preventing a decrease in hole quality. Therefore, if the drill bit T is held by the tool drive device 1 and the workpiece W is pierced using the drill bit T rotated by the tool drive device 1, a pierced part with a hole of good quality can be manufactured. For example, as... Figure 1 As an example, even when piercing workpieces W made of overlapping CFRP or other FRP and metals such as aluminum or titanium, it is possible to produce pierced parts with good quality holes because the metal chips are cut off and do not clog the slots of the drill bit T.
[0068] Furthermore, with the existing vibration mechanism, the vibration direction changes drastically not only when the ball enters the recess but also when it exits. As a result, the drill bit collides with the workpiece, or the perforation reaction force increases instantaneously. Therefore, sometimes the user is pushed back. However, with the vibration mechanism 8 of the tool drive device 1, the drill bit T has a low speed when it approaches the workpiece W, and the change in the perforation reaction force is also small. Therefore, it is possible to avoid the drill bit T colliding with the workpiece W and breaking, or being pushed back by the perforation reaction force while the user holds the tool drive device 1 by hand.
[0069] Furthermore, in the case of the ball moving in and out of the recess as in the existing vibration mechanism, the ball repeatedly contacts the edge of the recess when it comes out of the recess, resulting in wear of the ball and the edge of the recess. However, in the case of the vibration mechanism 8 of the tool drive device 1, there is no step for the ball 10 to climb on the sliding surface 9. Therefore, wear of the ball 10 caused by repeated collisions between the ball 10 and the edge of the step can be avoided.
[0070] (Second Implementation)
[0071] Figure 10 This is a partial cross-sectional view showing the structure of the tool driving device according to the second embodiment of the present invention.
[0072] exist Figure 10 In the tool drive device 1A shown in the second embodiment, the structure in which the plurality of balls 10 constituting the vibration mechanism 8A rotate and roll relative to both the drill chuck 2 and the frame 4 differs from that of the tool drive device 1 in the first embodiment. Regarding other structures and functions of the tool drive device 1A in the second embodiment, since they are not substantially different from those in the first embodiment, only the vibration mechanism 8A is shown in the illustration, and identical or corresponding structures are labeled with the same symbols and their descriptions are omitted.
[0073] When the positions of the multiple balls 10 are not fixed relative to either the drill chuck 2 or the frame 4, allowing them to rotate and move, it is sufficient that the annular ball retainer 20, which rollably holds a portion of the multiple balls 10, is not fixed to either the drill chuck 2 or the frame 4, but is rotatably positioned in the rotational direction encompassing both the forward and reverse directions of the drill chuck 2, i.e., centered on the tool axis AX. The ball retainer 20 is, for example, as shown below. Figure 10 For example, it can be rotatably configured within the space formed between the fixed ring 11 fixed to the frame 4 and the rotating ring 12 fixed to the drill chuck 2.
[0074] Figure 11 yes Figure 10 The enlarged longitudinal sectional view of the vibration mechanism 8A shown is shown. Figure 12 It is by Figure 11 The left-side view shown depicts the state in which the ball cage 20 holds the plurality of balls 10. Figure 13 yes Figure 11 The right side view of the rotating ring 12 shown.
[0075] like Figure 11 and Figure 12 For example, a ball retainer 20, which has a number of through holes formed on an annular plate, can hold a plurality of balls 10 and is disposed between a fixed ring 11 and a rotating ring 12. Additionally, in Figure 11 and Figure 12In the example shown, the fixed ring 11 is provided with a cylindrical edge having an inner diameter larger than the outer diameter of the rotating ring 12, so that the ball retainer 20 can be housed between the fixed ring 11 and the rotating ring 12.
[0076] like Figure 13 As exemplified, a sliding surface 9 with a step 9A is provided on the rotating ring 12, which is the inner surface of the groove 9B with a slope, similar to that in the first embodiment. Of course, when the groove 9B with a slope is formed on the rotating ring 12, such as... Figures 7-9 For example, the bottom surface of slot 9B can also be partially or partially tilted.
[0077] As shown in the figure, when the ball retainer 20 is rotatable relative to both the fixed ring 11 and the rotating ring 12, because the perforation reaction force acts on both the balls 10 and the rotating ring 12 and the balls 10 and the fixed ring 11, each ball 10 rolls and rotates relative to both the fixed ring 11 and the rotating ring 12 through the frictional forces between the balls 10 and the rotating ring 12 and between the balls 10 and the fixed ring 11. That is, each ball 10 rotates and rolls relative to the drill chuck 2 and the frame 4.
[0078] Therefore, as Figure 10 As exemplified, grooves 11A of a certain depth can be formed on the retaining ring 11 to allow each ball 10 to roll. Furthermore, if the cross-sectional shape of the groove 11A is made arc-shaped so that the inner surface of the groove 11A fits against each ball 10, each ball 10 rolls while in line contact with the inner surface of the groove 11A, thus delaying the rate of wear of each ball 10. Alternatively, a sliding surface 9 with a step 9A, formed as the inner surface of a groove 9B with a slope, can be formed on the retaining ring 11 side.
[0079] According to the second embodiment described above, in addition to the same effects as the first embodiment, it also achieves the effect of significantly reducing the friction between each ball 10 and the fixed ring 11 and the rotating ring 12. That is, as in the first embodiment, when the fixed ring 11 with a spherical recess is used as a ball retainer to hold multiple balls 10, each ball 10 will inevitably slide and roll relative to either the fixed ring 11 or the rotating ring 12. Therefore, when the rotational speed of the drill bit T and the drill chuck 2 is high, the friction between each ball 10 and the fixed ring 11 and the rotating ring 12 increases, and each ball 10 may wear out in a short time.
[0080] In particular, when drilling with a small-diameter drill bit T with a tool diameter of approximately 3mm to 10mm, the rotational speed of the drill bit T is mostly between 2000 rpm and 6000 rpm. Actual prototype tests conducted under these drilling conditions confirmed that the balls 10 wear due to frictional heating to above 100°C, resulting in a reduction in the diameter of the balls 10. Therefore, when using a small-diameter drill bit T for drilling, from the viewpoint of ensuring tool life, the second embodiment is preferable, as it reduces the frictional force between each ball 10 and the fixed ring 11 and rotating ring 12 to a level that can be disregarded.
[0081] (Other implementation methods)
[0082] The above describes specific embodiments, but these embodiments are merely examples and do not limit the scope of the invention. The new methods and apparatus described herein can be embodied in various other ways. Furthermore, various omissions, substitutions, and modifications can be made to the methods and apparatus described herein without departing from the spirit of the invention. The appended claims and their equivalents, as included within the scope and spirit of the invention, encompass such various methods and modifications.
[0083] Symbol Explanation
[0084] 1.1A Tool Drive Device
[0085] 2-bit chuck
[0086] 3 motors
[0087] 3A motor housing
[0088] 4 frames
[0089] 5 spindles
[0090] 6 hands
[0091] 7 switches
[0092] 8. 8A Vibration Mechanism
[0093] 9 sliding surfaces
[0094] 9A Steps
[0095] 9B slot
[0096] 10 ball bearings
[0097] 11. Fixing ring
[0098] 11A Slot
[0099] 12 rotating rings
[0100] 20 ball cage
[0101] AX tool axis
[0102] T-bit
[0103] W workpiece.
Claims
1. A tool driving device, the tool driving device being a handheld tool driving device having a handle for a user to grip and capable of piercing objects obtained from composite fiber reinforced plastics and metals, comprising: A drill chuck, which holds the drill bit; A motor that rotates the drill bit chuck; The frame housing the motor; as well as A vibration mechanism, which periodically reciprocates the drill chuck along the tool axis relative to the frame during rotation, moves the drill chuck away from the frame at a speed less than the speed at which the drill chuck approaches the frame. The vibration mechanism has the following features: - Multiple balls, which are rotatably separated at equal intervals on the same circle between the drill chuck and the frame; - A sliding surface, which is directly or indirectly disposed on one of the drill chuck and the frame, and is a sliding surface that allows the plurality of balls to roll and contact each other during the rotation of the drill chuck. The sliding surface has a plurality of steps at equal intervals, determined such that the plurality of balls fall simultaneously during the forward rotation of the drill chuck, with a drop difference of 0.01 mm to 0.15 mm. The steps smoothly change from each step toward the adjacent step without creating steps that would allow the plurality of balls to climb during the forward rotation of the drill chuck. - A ball retainer that rotatably holds the plurality of balls, the ball retainer being rotatably disposed about the tool shaft. The plurality of balls rotate and roll relative to the drill chuck and the frame.
2. A method for manufacturing a perforated part, wherein, The drill bit is held by the tool drive device as described in claim 1, and the drill bit, which is rotated by the tool drive device, is used to pierce the piercing object, thereby producing a pierced part.