JPH078106Y2 - Clutch mechanism of tap holder - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a clutch mechanism of a tap holder for tapping.

[Prior art]

An example of the clutch mechanism of the conventional tap holder will be described with reference to FIGS. 5 to 7. In FIG. 5 and FIG. 6, reference numeral 1 denotes a rotary shaft that detachably holds the tap 2, and the rotary shaft 1 is detachably fitted and inserted into a main shaft (not shown) that rotates in the forward and reverse directions of a machine tool. It is rotatably and detachably held by the tap holder body 3 to which the driving force is transmitted from the main shaft. On the outer peripheral surface of the rotary shaft 1, a retainer 4 to which the driving force is transmitted from the holder body 3, a taper cone 5, and a clutch spring 6 composed of a plurality of disc springs are provided from the intermediate portion of the outer peripheral surface of the rotary shaft 1 to the tip side. These members are sequentially fitted toward each other, and these members are attached to the retainer 4
Together with the plurality of clutch balls 7 held by the rotary shaft 1
The clutch mechanism 9 is configured by being housed in the clutch case 8 arranged on the outer peripheral side. That is, the clutch mechanism 9 is, as shown in FIG.
Support grooves 1a along the axial direction are formed on the outer peripheral surface of the large outer diameter portion of the rotary shaft 1 at three positions in the circumferential direction at equal intervals, and clutch balls 7 are removably engaged and supported in the support grooves 1a, respectively. There is.
Further, the retainer 4 is rotatably fitted onto the outer peripheral surface of the rotary shaft 1 so as not to move in the axial direction, and the clutch balls 7 are respectively inserted into the notches 4a formed at the tip of the retainer 4.
Is held movably in the radial direction and immovable in the circumferential direction, and an engaging projection piece 4b is abutted on the distal end side of the retainer 4. Further, a taper cone 5 is fitted on the outer peripheral surface of the rotary shaft 1 so as to be rotatable and movable in the axial direction of the rotary shaft 1, and the taper cone 5 is urged toward the retainer 4 by a clutch spring 6 and is attached to the tip of the retainer cone 5. By being able to contact, the clutch ball 7 is pressed toward the center side of the rotating shaft 1 by the tapered portion 5a on the inner peripheral surface of the tapered cone 5. The inner peripheral flange 8a provided at the end of the clutch case 8 is engaged with the end surface of the retainer 4 from the end side, and the adjustment nut 10 for supporting the clutch spring 6 is provided on the inner peripheral surface of the front end of the clutch case 8. When the nut 10 is screwed and moved in the axial direction, the clutch spring 6
Thus, the pressing force for pressing the clutch ball 7 toward the center of the rotary shaft 1 via the tapered cone 5 can be adjusted. In FIG. 5, 11 is an adjusting nut 10.
A loosening prevention mechanism including a taper cylinder (12) inserted into the tape and a bolt (13) screwed into the taper cylinder (12). Further, 15 is a tap holding mechanism, and this holding mechanism 15 is
The square shaft portion 2a of the tap 2 is fitted into the square hole portion 1b of the rotary shaft 1,
The ball 16 pressed against the outer peripheral surface of the handle portion of the tap 2 is
The sleeve 17 is fitted and held in the hole 17a of the sleeve 17 that is loosely inserted into the tip of the rotary shaft 1, and the sleeve 17 is urged toward the tip side in the axial direction by the compression spring 18 built in the tip of the rotary shaft 1 The tap 2 is retained and held by the ball 16 interposed between the tapered surface 1c formed on the inner circumference of the tip portion of the shaft 1 and the outer surface of the handle portion of the tap 2. In the conventional clutch mechanism of the tap holder configured as described above, the driving force is transmitted from the tap holder body 3 to the engaging protrusion 4b of the retainer 4 by the positive rotation of the main shaft of the machine tool, and the retainer 4 and the clutch ball The rotary shaft 1 is rotated via 7, and the tap 2 is rotated by fitting the square shaft portion 2a into the square hole portion 1b of the rotary shaft 1. When a load equal to or greater than a predetermined cutting torque is generated while tapping the workpiece by the rotation of the tap 2, the clutch ball 7 is disengaged from the support groove 1a formed on the rotating shaft 1. Although it rotates integrally with the retainer 4 while repeating, the rotating shaft 1 is prevented from rotating to prevent accidents such as breakage of the tap 2. If the tapped hole of the workpiece is a shallow impermeable hole, tapping must be performed until the tip of the tap 2 hits the bottom of the tapped hole. In this case, tapping is required. When the tip of hits the bottom of the tap pilot hole,
The load applied to the tap increases, and the clutch ball 7 repeatedly engages and disengages with the support groove 1a as in the case described above, and the rotary shaft 1 does not rotate. Further, conventionally, as shown in FIG. 8, circular hole-shaped support holes 1d are formed around the outer circumference of the rotary shaft 1 in the circumferential direction with the radius of the rotary shaft 1 as the center. A clutch mechanism is known in which each of the clutch mechanisms is engaged and supported in a disengageable manner. In this clutch mechanism, the clutch ball is held in the round hole formed in the retainer so that the same operation as that of the tap holder shown in FIGS. 5 to 7 can be performed.

[Problems to be solved by the device]

In the conventional clutch mechanism of the tap holder configured as described above, the adjustment nut 10 is moved in the axial direction to adjust the biasing force of the taper cone 5 by the clutch spring 6 to adjust the tapping torque of the workpiece. The transmission torque for transmitting the driving force from the clutch ball 7 to the rotating shaft 1 is set to be suitable for However, in the clutch mechanism shown in FIGS. 5 to 7, since the clutch ball 7 is engaged and supported by the support groove 1a along the axial direction of the rotary shaft 1, the transmission torque is set to a required magnitude. It is difficult to do so
In the case where the clutch ball is engaged and supported in the round hole-shaped support hole 1d shown in the drawing, it is easy and preferable to set the transmission torque to a required magnitude. However, in the clutch mechanism of the conventional tap holder, the support groove 1a of the rotary shaft 1 and the support hole 1d in the shape of a round hole are formed by the disengagement operation.
The clutch ball 7 engaged with the escapes from the support groove and the support hole, rides on the outer peripheral surface of the rotary shaft, and moves while rolling in the circumferential direction of the rotary shaft. When the clutch ball escapes, a large load is applied to the corner portion sandwiched between the support hole wall, the support groove wall and the outer peripheral surface, and the clutch mechanism is repeatedly engaged and disengaged, so that the corner portion is worn. Before the clutch mechanism is used, the outer peripheral surface of the rotating shaft and the outer surface of the clutch ball are in point contact, but when the outer peripheral surface of the rotating shaft is worn, the outer surface of the ball makes a line contact in the circumferential direction of the rotating shaft. Since the clutch ball moves in the circumferential direction of the rotating shaft in this state, a groove is formed along the circumferential direction at the corner, and the groove is wide and deep as the clutch ball is repeatedly engaged and disengaged. Since the outer surface of the clutch ball and the outer peripheral surface of the rotary shaft are both convex arcs, the clutch ball moves in the circumferential direction of the outer peripheral surface of the rotary shaft in a line contact state, and the outer peripheral surface is worn. Rapidly progresses, and the amount of wear of the corner increases rapidly. For this reason, the clutch ball easily comes out of the support hole in the support groove of the rotating shaft, the initial set torque is lowered, and the clutch mechanism is in a disengaged state during tapping. This invention is intended to solve the above-mentioned problems, in which a clutch ball is removably engaged and supported in a round hole-shaped support hole provided in a rotary shaft, but a support hole wall is provided. The purpose of the present invention is to provide a tap holder that can easily slow down the wear of the corners sandwiched between the outer peripheral surface of the rotary shaft and the original setting torque for a long time and can perform stable tapping. I am trying.

[Means for Solving the Problems]

This invention is such that in the clutch mechanism of the tap holder as described above, the flat surface 1e orthogonal to the axial direction of the support hole 1d having a round hole is in contact with the outer periphery of the support hole 1d and has an appropriate size independently. It is formed on the outer peripheral surface of the rotary shaft 1, and the outer peripheral surface of the clutch ball 7 is line-contacted with the inner peripheral surface of the support hole 1d so as to be detachably supported.

[Action]

The clutch mechanism of the tap holder according to the present invention has circular hole-shaped support holes formed at a plurality of positions in the circumferential direction of the outer peripheral surface of the rotary shaft for holding the taps at equal intervals, and a flat hole orthogonal to the axial direction of these support holes. By forming the rotary shaft on the outer peripheral surface so as to contact the outer periphery of the support hole, the clutch ball escapes from the round hole-shaped support hole by the disengagement operation of the clutch mechanism, and the flat surface of the outer peripheral surface of the rotary shaft is formed. Even when the outer surface of the clutch ball has a convex arc shape when riding on the vehicle and moving in the circumferential direction of the rotating shaft, the outer peripheral surface of the rotating shaft contacting these is a flat surface orthogonal to the axial direction of the support hole. However, even if these flat surfaces gradually wear and a large load is applied to the corner portion a (see FIG. 3) sandwiched between the support hole wall and the flat surface, the progress of wear of the flat surfaces is slow. Clutch clutch for a long time But not easy to escape from the support hole,
Maintains the required set torque and enables stable tapping work. Further, compared to the above-mentioned conventional one, the number of parts does not increase, and the process of forming the flat surface on the outer peripheral surface of the rotary shaft can be easily performed, so that the cost is hardly increased. Furthermore, the contact between the support hole wall and the outer surface of the clutch ball is
The contact between the concave arc portion and the convex arc portion, wear on the side of the support hole wall, compared to the contact between the convex arc portions, the progress is slow,
Even if the wall of the support hole is worn, the clutch ball rarely comes out of the support hole, so that there is no problem in maintaining the set torque for a long period of time. Since the clutch ball is engaged and supported in the round hole-shaped support hole formed in the rotary shaft, the clutch ball is changed from the clutch ball to the rotary shaft in comparison with the clutch ball engaged in the support groove formed in the rotary shaft. The required torque for transmitting the driving force can be increased.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3, the same reference numerals as those in FIGS. 5 to 7 and 8 indicate the same or corresponding portions, and 1e indicates a round hole-shaped support hole 1d formed on the outer peripheral surface of the rotary shaft 1. A flat surface that touches the outer circumference and is formed independently of each other.
1e is orthogonal to the radial direction of the rotary shaft 1 passing through the axis of the support hole 1d and is parallel to the axial direction of the rotary shaft 1.
1f is a slightly chamfered portion formed in a conical shape at the opening end of the support hole 1d, and 4c is formed in the retainer 4 to restrain the clutch ball 7 in the circumferential direction and the axial direction, and further to rotate the rotary shaft. 1 is a round hole portion that is engaged and held so as to be movable in the radial direction. Further, in FIG. 1, 19 is a square hole washer inserted between the compression spring 18 of the holding mechanism 15 and a step provided in contact with the tip of the square hole 1b on the inner circumference of the rotary shaft 1, and 20 is a sleeve 17. The lock bolt is screwed into the tip portion 17b protruding from the tip of the rotary shaft 1 and presses the outer peripheral surface of the tap 2. The above-mentioned configuration of this embodiment is the same as that shown in FIGS. 5 to 7. In the clutch mechanism of the embodiment configured as described above, the clutch ball 7 is engaged and supported in the round hole-shaped support hole 1d formed in the rotary shaft 1, so that the urging force of the clutch spring 6 is adjusted. , The transmission torque for transmitting the driving force from the clutch ball 7 to the rotary shaft 1 can be easily set to a required magnitude, and the flat surface 1e is provided on the outer peripheral side of the support hole 1d to open the clutch ball 7 and the support hole 1d wall end. Since it is arranged so as to substantially come into contact with the annular portion, the clutch ball 7 is held in the supporting hole when the clutch is disengaged.
Even if engagement / disengagement is repeated with respect to 1d, the wear of the corner portion a (see FIG. 3) sandwiched between the support hole 1d wall and the flat surface 1e of the outer peripheral surface of the rotary shaft 1 can be delayed. That is, support holes 1d in the form of round holes are formed at equal intervals in the radial direction of the rotary shaft 1 at three circumferential positions on the outer peripheral surface of the rotary shaft 1 that holds the taps 2, and the entire outer circumference of these support holes 1d is formed. By forming a flat surface 1e on the outer peripheral surface of the rotating shaft 1 so as to be in contact with and outside the supporting hole 1d at right angles to the axial direction of the supporting hole 1d, the clutch ball 7 rolls by the disengagement operation of the clutch mechanism while the supporting hole 1d Escape from the flat surface of the outer peripheral surface of the rotating shaft 1.
Even when the outer surface of the clutch ball 7 has a convex arc shape when riding on 1e and moving in the circumferential direction of the rotary shaft 1, the outer peripheral surface of the rotary shaft 1 contacting these is flat and orthogonal to the axial direction of the support hole 1d. Since the flat surface 1e is gradually worn, even if a large load is applied to the corner portion a sandwiched between the support hole 1d wall and the flat surface 1e, the progress of wear of the flat surface 1e is slow. As a result, the ball 7 does not easily come out of the support hole 1d for a long time, the set torque is maintained for a long time, and stable tapping work can be performed. Moreover, the contact between the wall of the support hole 1d and the outer surface of the clutch ball 7 is the contact between the concave arc portion and the convex arc portion, and the progress of wear on the wall side of the support hole 1d is relatively slow, and the support hole 1d Even if the wall is worn, the clutch ball 7 hardly escapes from the support hole 1d, so there is no problem in maintaining the set torque for a long period of time. As shown in FIG. 2, the flat surface 1e surrounds the entire circumference of the support hole 1d and has a rectangular shape having an appropriate length and width in the axial direction and the circumferential direction of the rotary shaft 1 and the outer circumference thereof. It is preferably formed into a shape. FIG. 4 shows another embodiment of the present invention. In FIG. 4, the same reference numerals as those in FIGS. 1 to 3 indicate the same or corresponding portions, and in this embodiment, the taper portion 1g provided on the rotary shaft 1 and having a small diameter on the tip side has a predetermined axial direction with respect to the rotary shaft 1. Support holes 1d centered on an axis inclined at equal angles 3 at equal intervals in the circumferential direction
Individually formed, a flat surface 1e is formed in contact with the outer periphery of the support hole 1d on the outer peripheral surface of the tapered portion 1g and orthogonal to the axial direction of the support hole 1d and the circumferential direction and width direction of the tapered portion 1g. Further, in this embodiment, the compression spring of the tap holding mechanism 15 is eliminated, and the clutch ball 7 is held in the notch 4a of the retainer 4. The structure and operation of this embodiment other than those described above are the same as those shown in FIGS. Further, in the embodiment shown in FIG. 4, when the diameter of the tap 2 is very small, it is required to reduce the outer diameter of the tip end portion on the gripping side of the rotating shaft 1 in order to facilitate handling, and the tapping is relatively performed. It is applied when the diameter of the tip side of the rotary shaft 1 is made smaller than that of the terminal end which is the handle side. In this invention, the tap holding mechanism that detachably holds the tap on the rotary shaft and the portion that transmits the driving force to the retainer of the tap holder body can be appropriately configured.

[Effect of device]

As described above, in the clutch mechanism of the tap holder according to the present invention, round hole-shaped support holes are formed at a plurality of positions in the circumferential direction of the outer peripheral surface of the rotating shaft that holds the taps at equal intervals. By forming a flat surface orthogonal to the axial direction on the outer peripheral surface of the rotating shaft so as to contact the outer periphery of the supporting hole, the clutch ball escapes from the round hole-shaped supporting hole by the disengagement operation of the clutch mechanism, Even when the outer surface of the clutch ball has a convex arc shape when riding on the flat surface of the outer peripheral surface and moving in the circumferential direction of the rotary shaft, the outer peripheral surface of the rotary shaft contacting these is orthogonal to the axial direction of the support hole. Since these flat surfaces gradually wear, even if a large load is applied to the corner a (see FIG. 3) sandwiched between the support hole wall and the flat surface, the flat surfaces are worn. Slowing down the Not Tatte clutch ball tends to escape from the support hole, and maintain the required setting torque, it is stable tapping work. Further, compared to the above-mentioned conventional one, the number of parts does not increase, and the process of forming the flat surface on the outer peripheral surface of the rotary shaft can be easily performed, so that the cost is hardly increased. Furthermore, the contact between the support hole wall and the outer surface of the clutch ball is
The contact between the concave arc portion and the convex arc portion, wear on the side of the support hole wall, compared to the contact between the convex arc portions, the progress is slow,
Even if the wall of the support hole is worn, the clutch ball hardly escapes from the support hole, so that there is no problem in maintaining the set torque for a long period of time.

[Brief description of drawings]

FIG. 1 is a side view showing a clutch mechanism of a tap holder according to an embodiment of the present invention, FIG. 2 is a perspective view showing a main part of a rotary shaft of FIG. 1, and FIG. 3 is a supporting hole of FIG. FIG. 4 is an enlarged cross sectional view showing a portion, FIG. 4 is a half sectional side view showing a clutch mechanism according to another embodiment of the present invention, and FIG. 5 is a half sectional side view showing an example of the clutch mechanism of the conventional tap holder.
5 is an enlarged sectional view taken along line VI-VI of FIG. 5, FIG. 7 is an exploded perspective view showing the rotary shaft and retainer of FIG. 5, and FIG. 8 is a perspective view showing a modification of the conventional rotary shaft. 1 ... Rotary axis, 1d ... Support hole, 1e ... Flat surface, 2 ... Tap, 3 ... Tap holder body, 4 ... Retainer,
5 ... taper cone, 6 ... clutch spring, 7 ... clutch ball, 8 ... clutch case, 9 ... clutch mechanism, 10 ... adjustment nut.

Claims (1)

[Scope of utility model registration request] 1. An axial direction of the rotary shaft 1 which is open at the outer circumferential surface of the rotary shaft 1 at a plurality of positions in the circumferential direction of the rotary shaft 1 which detachably holds the taps 2, and which is open toward the center of the rotary shaft 1. Circular hole-shaped support holes 1d extending in an intersecting manner are formed at equal intervals, and the clutch balls 7 are engageably supported in the support holes 1d in a disengageable manner, and a driving force is transmitted from the spindle side of the machine tool. The retainer 4 is rotatably fitted to the outer peripheral surface of the rotary shaft 1 while restraining the axial movement thereof, and the retainer 4 holds the clutch ball 7 movably in the axial direction of the support hole 1d. Tapered cone 5 placed on the tip side of 4
Is rotatably fitted to the outer peripheral surface of the rotary shaft 1, and a clutch spring 6 for urging the tapered cone 5 toward the distal end is disposed on the outer peripheral side of the rotary shaft 1, and the distal end engages with the retainer 4. An adjusting nut 10 is screwed onto the tip of a clutch case 8 that covers the retainer 4, the taper cone 5 and the clutch spring 6, and the adjusting nut 10 supports the clutch spring 6, and the inner peripheral surface of the taper cone 5 allows the clutch ball to move. In the clutch mechanism of the tap holder in which 7 is pressed toward the center of the rotating shaft 1, a flat surface 1e orthogonal to the axial direction of the support hole 1d having a round hole shape is formed.
Are formed on the outer peripheral surface of the rotary shaft 1 in contact with the outer periphery of the support hole 1d and have an appropriate size independently, and the outer peripheral surface of the clutch ball 7 is brought into line contact with the inner peripheral surface of the support hole 1d to engage with each other. Clutch mechanism for tap holders that is detachably supported.