Rolling tool unit

Abstract

To provide a rolling tool unit which enables easy adjustment between centers of dies.SOLUTION: Three dies 20 are held on a top surface of a columnar pedestal 30, and slits are formed between seating surfaces. A connection part 76 of a connecting shaft 70 is connected to the pedestal 30. A shaft part 71 of the connecting shaft 70 extends in a rod-like form in an area below the connection part 76. A holding part 51 of a holder 50 has a recessed part shape and holds the pedestal 30. The shaft part 71 is inserted into a through hole 57 of the holder 50. When the connecting shaft 70 moves downward, the pedestal 30 is drawn into the recessed part of the holding part 51. An outer peripheral surface 30A of the pedestal 30 is compressed in a radial inward direction by a recessed part inner peripheral surface 51A of the holding part 51 to decrease slit widths, thereby reducing spaces between centers of the dies 20. When the connecting shaft 70 moves upward, the pedestal 30 is pushed out from the recessed part of the holding part 51. Pressing force applied by the recessed part inner peripheral surface 51A and acting on the outer peripheral surface 30A of the pedestal 30 is reduced to increase the slit widths, thereby increasing the spaces between the centers of the dies 20.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a rolling tool unit that is attached to a processing device and rolls threads into a workpiece. [Background technology]

[0002] A rolling tool is known in which a base, which has a plurality of dies arranged around an insertion hole into which the workpiece is inserted, is held by a holding member and attached to a processing device such as a lathe to roll a thread into the workpiece. The base of the rolling tool described in Patent Document 1 has slits formed in it that extend radially from the central insertion hole toward the area where the dies are arranged. The slit spacing of the base is changed by the amount of tightening of an adjustment bolt, thereby adjusting the center-to-center distance of the dies. The body of the holding member has a recessed shape, and the base is placed within the body. An annular restricting member is screwed onto the body to press the base, and the base is held by the holding member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Application No. 2022-85676 Summary of the Invention

[0004] To adjust the center distance of the die, it was necessary to remove the restricting member from the holding member, then remove the base from the holding member and adjust the tightening amount of the adjustment bolt, which was time-consuming.In addition, because the restricting member was screwed into the body of the holding member, if it became loose due to rotation during rolling, the base could become loose.

[0005] An object of the present invention is to provide a rolling tool unit that allows easy adjustment of the center distance between the dies.

[0006] According to one aspect of the present invention, there is provided a rolling tool unit comprising: a base having an insertion hole into which a workpiece is inserted; a rolling tool having a plurality of dies arranged around the insertion hole of the base; and a holder having an attachment portion to be attached to a processing device for the workpiece and a holding portion connected to the attachment portion and holding the rolling tool, the rolling tool unit rolling a thread on the workpiece inserted into the insertion hole, the rolling tool unit further comprising a connecting shaft having a rod-shaped shaft portion and a connecting portion at one end of the shaft portion that connects to the base, the mounting portion of the holder is tubular with a through hole formed therethrough, the holding portion of the holder has a recessed inner surface that tapers in diameter toward the bottom surface, the connecting shaft is connected to one end of the mounting portion on the bottom surface side, and the bottom surface is connected to the through hole of the mounting portion, the connecting shaft is inserted into the through hole, and the connecting portion is disposed within the holding portion and connects to the base.

[0007] The connecting shaft is inserted through the through-hole of the mounting portion, so when the other end of the connecting shaft is pulled from the other end of the mounting portion, the base connected to the connecting portion at one end is pulled into the recess of the holding portion. The base is compressed radially inward by the tapered recess, making it possible to narrow the distance between the centers of the multiple dies. When the other end of the connecting shaft is pushed in from the other end of the mounting portion, the base is pushed out from the recess of the holding portion. The compression of the base by the tapered recess is released, making it possible to widen the distance between the centers of the multiple dies. In addition, because the connecting shaft presses the base against the holding portion, rattling of the base can be suppressed.

[0008] In this aspect, the other end of the shaft portion of the connecting shaft may be threaded, and a nut may be provided that screws onto the other end. By turning the nut, the connecting shaft can pull the base into the recess of the holding member or push it out of the recess. Therefore, the rolling tool can easily adjust the centers of the multiple dies. Furthermore, because the connecting shaft is fixed to the holding member by the nut, rattle of the base can be suppressed.

[0009] In this aspect, the outer peripheral surface of the base may be tapered so that its diameter decreases toward the bottom surface of the holding portion when the base is held by the holding portion. Because the outer peripheral surface of the base and the inner peripheral surface of the holding portion are tapered so that their diameters decrease in the same direction, the holding portion can more gradually compress and expand the base in the radial direction in response to axial movement of the connecting shaft. Therefore, the rolling tool can more precisely adjust the centers of multiple dies.

[0010] In this aspect, the shaft portion and the connecting portion of the connecting shaft may be formed separately, the connecting portion may be flange-shaped and radially larger than the shaft portion, the insertion hole of the base may be formed with a step portion that connects to the connecting portion, and the shaft portion may be connected to the connecting portion via the through hole with the connecting portion disposed on the step portion. Because the shaft portion and the connecting portion of the connecting shaft are separate, when assembling the rolling tool, the connecting shaft can be assembled with the base already disposed in the holding portion. In other words, the rolling tool can be easily assembled because it is not necessary to simultaneously hold down the base and the connecting shaft when assembling the base to the holder.

[0011] In this aspect, one of the nut or the mounting portion may be provided with a scale indicating the relative rotational position of the nut and the mounting portion, and the other of the nut or the mounting portion may be provided with an index pointing to the scale. The user can check the center-to-center distance of the multiple dies from the position of the scale indicated by the index. Therefore, the rolling tool can more precisely adjust the center-to-center distance of the multiple dies. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a perspective view of the rolling tool unit 100. [Figure 2] FIG. 2 is an exploded perspective view of the rolling tool unit 100. [Figure 3] FIG. 2 is an exploded perspective view of the rolling tool 10. [Figure 4] FIG. [Figure 5]5 is a cross-sectional view of the base 30 taken along line II-II in FIG. 4 and viewed in the direction of the arrows. [Figure 6] 2 is a cross-sectional view of the rolling tool unit 100 taken along line II in FIG. 1 and viewed in the direction of the arrows. [Figure 7] FIG. 10 is an exploded perspective view of a modified connecting shaft 170. DETAILED DESCRIPTION OF THE INVENTION

[0013] A rolling tool unit 100 according to one embodiment of the present invention will be described below with reference to the drawings. The rolling tool unit 100 shown in FIG. 1 is a tool unit that is attached to a processing device (not shown), such as an automatic lathe or a turret lathe, and forms a male thread by rolling a thread on a workpiece, such as a metal bar. The rolling tool unit 100 is used, for example, to process fine threads (e.g., M2.6 or smaller) used in precision instruments. For convenience, in the following description, the direction along the axis P of the rolling tool unit 100 is defined as the up-down direction, and the upper side of the page in FIG. 1 is defined as the upper side of the rolling tool unit 100, and the lower side is defined as the lower side. Furthermore, the orientation of each component constituting the rolling tool unit 100 will be described based on the orientation of the assembled rolling tool unit 100.

[0014] As shown in Figures 1 and 2, the rolling tool unit 100 is a tool body in which a rolling tool 10 for rolling a thread on a workpiece is held in a holder 50 for mounting on a processing device. The rolling tool 10 includes a base 30 and a plurality of dies 20. As shown in Figures 3 and 4, the base 30 is cylindrical with a C-chamfered edge. An insertion hole 31 is formed in the center of the base 30, penetrating the base 30 along the axis P. During rolling, the workpiece is inserted into the insertion hole 31. The insertion hole 31 has an expanded diameter portion 31A, a reduced diameter portion 31B, and a step portion 31C. The expanded diameter portion 31A is the portion above the step portion 31C, and the reduced diameter portion 31B is the portion below the step portion 31C. The expanded diameter portion 31A has a larger inner diameter than the reduced diameter portion 31B. The step portion 31C connects the lower end of the enlarged diameter portion 31A and the upper end of the reduced diameter portion 31B in the radial direction of the axis P. As will be described later, a connecting shaft 70 is connected to the step portion 31C.

[0015] The base 30 has a plurality of (three in this embodiment) slits 34A, 34B, and 34C extending radially outward from the insertion hole 31. The slits 34A, 34B, and 34C are arranged at equal intervals in the circumferential direction of the axis P. The slits 34A, 34B, and 34C each penetrate the base 30 in the up-down direction. The slits 34A and 34B extend radially outward from the insertion hole 31 by a length of approximately ¾ of the radius. The slit 34C extends further radially outward than the slits 34A and 34B and connects to the outer peripheral surface 30A of the base 30. An end 34D of the slit 34C near the outer peripheral surface 30A has a wider width (size in the circumferential direction of the axis P) than the slit 34C. As will be described later, the slits 34A, 34B, and 34C are used to adjust the center-to-center distances of the multiple dies 20.

[0016] A plurality of (three in this embodiment) bearing surfaces 32 are formed on the top surface 30B of the base 30 on the upper and lower sides. Each bearing surface 32 has a circular recessed shape, and its inner diameter is slightly larger than the outer diameter of the die 20. The three bearing surfaces 32 are equally spaced apart in the circumferential direction, radially outward of the insertion hole 31 with respect to the axis P, and are formed between the three slits 34A, 34B, and 34C. A portion of each bearing surface 32 overlaps the portion where the insertion hole 31 is formed, and has a notched shape in plan view. The die 20 is placed on the bearing surface 32, and the axially lower end face of the die 20 is supported by the bearing surface 32. As shown in FIG. 5, the bearing surface 32 is inclined at an angle R1 in the circumferential direction of the axis P with respect to the top surface 30B of the base 30. The angle R1 corresponds to the lead angle of the male thread to be rolled into the workpiece, and is, for example, 4.3 degrees. Therefore, the dies 20 supported by the seating surfaces 32 are arranged in a state inclined at an angle R1 in the circumferential direction of the axis P.

[0017] As shown in Figures 3 and 4, a mounting hole 33 is formed in the center of the seat 32, extending in a direction perpendicular to the seat 32 and penetrating the base 30. The mounting hole 33 extends circumferentially at an angle R1 with respect to the axis P (see Figure 5). A support shaft 21 that supports the die 20 is inserted into the mounting hole 33. The support shaft 21 is fixed to the mounting hole 33 in the seat 32 while rotatably supporting the die 20. Also, as shown in Figure 5, the outer peripheral surface 30A of the base 30 tapers downward in the vertical direction. The angle R2 at which the outer peripheral surface 30A is inclined with respect to the axis P is, for example, 2 degrees.

[0018] As shown in Figure 3, the die 20 is formed in a cylindrical shape with a stepped through-hole 22 (see Figure 6), and has a plurality of (e.g., four) annular chevron shapes 23 without lead formed on the outer circumferential surface. The die 20 is attached to the base 30 with the attachment height positions differing by a predetermined amount (e.g., 1 / 3 of the lead (pitch) of the workpiece) so as to match the lead of the workpiece. The lead is the distance traveled in one rotation. In the case of a single-start screw, the pitch corresponds to the lead.

[0019] As shown in Figures 1, 2, and 6, the holder 50 for holding the rolling tool 10 has a holding portion 51 and an attachment portion 56. The holding portion 51 is cylindrical with a recess formed at the top, and is disposed with the opening of the recess facing upward. The inner diameter of the recess in the holding portion 51 is smaller than the maximum outer diameter of the base 30 and larger than the minimum outer diameter. The inner peripheral surface 51A of the recess in the holding portion 51 tapers toward the bottom surface 51B of the recess. The inner peripheral surface 51A is inclined relative to the axis P at an angle R3 of 1 degree, for example. The bottom portion 51C, which is the portion of the holding portion 51 below the bottom surface 51B of the recess, has a height that is approximately half the height of the holding portion 51 in the vertical direction (see Figure 6). A pin 52 extending in the vertical direction is embedded in the bottom surface 51B of the recess. The pin 52 is located near the inner peripheral surface 51A of the recess and protrudes upward from the bottom surface 51B of the recess. When the base 30 is held by the holder 50, the pin 52 is disposed within an end 34D of the slit 34C of the base 30. The width of the end 34D of the slit 34C is greater than the outer diameter of the pin 52. The pin 52 prevents the rolling tool 10 from rotating in the circumferential direction of the axis P in the holding portion 51.

[0020] A spring 40 is disposed between the bottom surface 51B of the recess of the holding portion 51 and the bottom surface of the seat 30 of the rolling tool 10. The spring 40 biases the seat 30 upward.

[0021] The mounting portion 56 is cylindrical and extends along the axis P, and has a through-hole 57 formed therethrough. The upper end of the mounting portion 56 connects to the bottom portion 51C of the holding portion 51. The outer diameter of the mounting portion 56 is smaller than the outer diameter of the holding portion 51. The through-hole 57 passes through the bottom portion 51C of the holding portion 51 and opens to the bottom surface 51B of the recess. A scale 58 is formed on the lower end of the outer circumferential surface 56A of the mounting portion 56, and has a plurality of scale lines engraved at equal intervals along the circumferential direction.

[0022] A connecting shaft 70 is disposed in the through hole 57 of the holder 50. The connecting shaft 70 is rod-shaped and extends in the vertical direction, and is longer than the length of the holder 50 in the vertical direction. The connecting shaft 70 includes a shaft portion 71 and a connecting portion 76. The shaft portion 71 is a rod-shaped portion that extends with an outer diameter smaller than the inner diameter of the through hole 57, and has a screw thread 72 formed at its lower end. When the shaft portion 71 is disposed in the through hole 57, the lower end protrudes downward beyond the lower end of the mounting portion 56, exposing the screw thread 72.

[0023] The connecting portion 76 is provided at the upper end of the shaft portion 71. The connecting portion 76 is flange-shaped and radially larger than the outer diameter of the shaft portion 71. When the shaft portion 71 is placed in the through-hole 57 while the base 30 is held by the holding portion 51, the connecting portion 76 is placed in the expanded diameter portion 31A of the base 30. The inner diameter of the reduced diameter portion 31B of the base 30 is approximately the same as the inner diameter of the through-hole 57, is larger than the outer diameter of the shaft portion 71, and is smaller than the outer diameter of the connecting portion 76. The inner diameter of the expanded diameter portion 31A of the base 30 is larger than the outer diameter of the connecting portion 76. Therefore, the lower surface of the connecting portion 76 engages with the stepped portion 31C of the base 30. The vertical thickness of the connecting portion 76 is shorter than the vertical length of the expanded diameter portion 31A of the base 30 and is approximately one-third of the expanded diameter portion 31A. Therefore, when a workpiece is inserted into the insertion hole 31 during rolling, a space is ensured so that the lower end (the tip in the insertion direction) of the workpiece does not come into contact with the connecting portion 76.

[0024] A nut 80 is engaged with threads 72 formed on the lower end of the connecting shaft 70. When fastened, the top surface of the nut 80 abuts against the bottom surface of the mounting portion 56 of the holder 50. When the nut 80 is tightened, the connecting shaft 70 moves downward relative to the holder 50, and the connecting portion 76 presses against the step portion 31C, causing the base 30 to move within the holding portion 51 in a direction approaching the recess bottom surface 51B. When the nut 80 is loosened, the connecting shaft 70 moves upward relative to the holder 50, and the spring 40 presses against the base 30, causing the base 30 to move within the holding portion 51 in a direction away from the recess bottom surface 51B.

[0025] An index 81 is formed on the side of the nut 80. The index 81 is, for example, a triangular mark that is engraved or printed. The tip of the index 81 faces upwards in the nut 80 and points to the scale 58 on the mounting portion 56 when the nut 80 is fastened. When the nut 80 is rotated, the position on the scale 58 that the index 81 points to changes.

[0026] Next, the assembly of the rolling tool unit 100 will be described. As shown in FIG. 6, the connecting shaft 70 is inserted from above into the insertion hole 31 of the base 30, and the connecting portion 76 is positioned in the expanded diameter portion 31A. The connecting shaft 70 is inserted into the through-hole 57 from the holding portion 51 side of the holder 50. The base 30 is positioned in the recess of the holding portion 51 while adjusting the orientation of the base 30 so that the pin 52 is positioned in the end 34D of the slit 34C of the base 30. The lower end of the shaft portion 71 is exposed below the mounting portion 56, and a nut 80 is engaged with the thread 72 and temporarily fastened. The support shaft 21 of the die 20 is inserted into the mounting hole 33 of the base 30, and the die 20 is positioned on the seat surface 32 and fixed rotatably.

[0027] Next, the center-to-center adjustment of the die 20 will be described. When the nut 80 is rotated in the tightening direction, the connecting shaft 70 moves downward relative to the holder 50. The connecting portion 76 abuts against the step portion 31C of the insertion hole 31 of the base 30 and presses the step portion 31C downward. The base 30 moves downward against the biasing force of the spring 40. The taper angle R2 of the outer peripheral surface 30A of the base 30 is larger than the taper angle R3 of the inner peripheral surface 51A of the recess of the holding portion 51, and the outer peripheral surface 30A of the base 30 is pressed radially inward by the inner peripheral surface 51A of the recess of the holding portion 51. This pressure causes the base 30 to bend at the ends of the slits 34A and 34B. The widths of the slits 34A, 34B, and 34C each narrow, thereby reducing the diameter of the base 30. As a result, the support shafts 21 that support the dies 20 come closer to each other, so that the distance between the centers of the dies 20 can be narrowed.

[0028] When the nut 80 is rotated in the direction of loosening, the connecting shaft 70 moves upward relative to the holder 50. The force with which the connecting portion 76 presses the step portion 31C downward weakens, and the biasing force of the spring 40 causes the base 30 to move upward relative to the holding portion 51. The force with which the inner peripheral surface 51A of the recess of the holding portion 51 presses the outer peripheral surface 30A of the base 30 weakens, and the deflection at the ends of the slits 34A and 34B of the base 30 returns to normal. The widths of the slits 34A, 34B, and 34C each increase, thereby expanding the diameter of the base 30. As a result, the support shafts 21 supporting the dies 20 move away from each other, thereby increasing the center-to-center distance of the dies 20.

[0029] When rolling threads into a workpiece, the rolling tool unit 100 is attached to the processing device. The processing device is operated, and the workpiece is inserted between the dies 20 toward the insertion hole 31 of the rolling tool 10 while supplying lubricating oil to the seating surface 32 or the dies 20. As the dies 20 rotate, threads are raised on the outer surface of the workpiece. Next, the workpiece is moved in the opposite direction to the insertion direction. While rotating the dies 20 in the opposite direction, the workpiece is removed from the insertion hole 31 and between the dies 20, completing the rolling process.

[0030] When adjusting the center distance of the die 20, the position of the index 81 of the nut 80 pointing to the scale 58 of the holder 50 can be recorded to adjust the rolling condition of the thread to be rolled into the workpiece. If the rolled thread is smaller than specified, the nut 80 is rotated in a tightening direction, and the amount of rotation is adjusted based on the scale 58 to roll the thread into the workpiece. If the rolled thread is larger than specified, the nut 80 is rotated in a loosening direction, and the amount of rotation is adjusted based on the scale 58 to roll the thread into the workpiece. In this way, by using the scale 58 and the index 81 to adjust the tightening position of the nut 80 to a position where the appropriate thread will be rolled, the center distance of the die 20 can be easily adjusted. Furthermore, by recording the position of the scale 58 pointed to by the index 81, the tightening position of the nut 80 can be easily adjusted to a position where the appropriate thread will be rolled, for example, when the rolling tool unit 100 is disassembled and reassembled for maintenance.

[0031] As described above, the connecting shaft 70 is inserted through the through-hole 57 of the mounting portion 56. When the lower end of the connecting shaft 70 is pulled from the lower end of the mounting portion 56, the base 30 connected to the connecting portion 76 at the upper end is pulled into the recess of the holding portion 51. The base 30 is compressed radially inward by the tapered inner circumferential surface 51A of the recess, thereby narrowing the distance between the centers of the multiple dies 20. When the lower end of the connecting shaft 70 is pressed from the lower end of the mounting portion 56, the base 30 is pushed out of the recess of the holding portion 51. The compression of the base 30 by the tapered inner circumferential surface 51A of the recess is released, thereby widening the distance between the centers of the multiple dies 20. Furthermore, because the connecting shaft 70 presses the base 30 against the holding portion 51, rattle of the base 30 is suppressed.

[0032] By turning the nut 80, the connecting shaft 70 can pull the base 30 into or push it out of the recess of the holding part 51. Therefore, the rolling tool 10 can easily adjust the center distance between the multiple dies 20. In addition, because the connecting shaft 70 is fixed to the material of the holding part 51 by the nut 80, rattling of the base 30 can be suppressed.

[0033] Since the outer peripheral surface 30A of the base 30 and the inner peripheral surface 51A of the recess of the holding portion 51 are tapered so that the diameter decreases in the same direction, the holding portion 51 can more gradually compress and expand the base 30 in the radial direction in response to the axial movement of the connecting shaft 70. Therefore, the rolling tool 10 can more precisely adjust the center-to-center distances of the multiple dies 20.

[0034] The user can check the size of the center spacing between the multiple dies 20 from the position of the scale 58 indicated by the indicator 81. Therefore, the rolling tool 10 can adjust the center spacing between the multiple dies 20 more precisely.

[0035] In the above description, the upper end of the shaft portion 71 is an example of "one end of the shaft portion" of the present invention. The lower end of the shaft portion 71 is an example of "the other end of the shaft portion" of the present invention. The inner peripheral surface 51A of the recess is an example of "the inner peripheral surface" of the holding portion of the present invention. The bottom surface 51B of the recess is an example of "the bottom surface" of the holding portion of the present invention.

[0036] The present invention is not limited to the above-described embodiments and various modifications are possible. The connecting portion 76 and the shaft portion 71 of the connecting shaft 70 may be provided separately. For example, as shown in FIG. 7 , a female thread portion 172 is formed downward from the top surface at the upper end of the shaft portion 171. A male thread portion 177 protruding downward is formed on the connecting portion 176. The connecting shaft 170 can be constructed by fastening the connecting portion 176 to the shaft portion 171. By forming the shaft portion 171 and the connecting portion 176 of the connecting shaft 170 separately in this manner, the connecting shaft 170 can be assembled with the base 30 already positioned in the holding portion 51 when assembling the rolling tool 10. In other words, the rolling tool 10 can be easily assembled because it is not necessary to simultaneously hold down the base 30 and the connecting shaft 170 when assembling the base 30 to the holder 50.

[0037] The base 30 and the connecting shaft 70 may be formed integrally. Alternatively, the base 30 and the connecting shaft 70 may be connected by, for example, engaging the connecting portion 76 of the connecting shaft 70 with the insertion hole 31 of the base 30, and the base 30 may move up and down in conjunction with the up and down movement of the connecting shaft 70. When the base 30 and the connecting shaft 70 are configured in this way, the spring 40 may be unnecessary.

[0038] The bottom surface of the mounting portion 56, the top surface of the nut 80, or both may be embossed to have an anti-slip function. Alternatively, two nuts 80 may be fastened to the threads 72 of the connecting shaft 70 to prevent the nuts 80 from loosening. Alternatively, the mounting portion 56 or the nuts 80 may have a function to prevent the nuts 80 from rotating, so that rotation of the nuts 80 due to external disturbances can be prevented after the nuts 80 have been positioned based on the scale 58.

[0039] Although the outer peripheral surface 30A of the base 30 and the inner peripheral surface 51A of the recess of the holding portion 51 of the holder 50 are each formed tapered, it is also possible to form either the outer peripheral surface 30A or the inner peripheral surface 51A of the recess tapered, and not form the other tapered. [Explanation of symbols]

[0040] 10 Rolling tools 20 dice 30 pedestal 30A outer surface 31 Insertion hole 31C Stepped section 50 holder 51 Holding part 51A Inner surface of recess 56 Mounting part 57 Through hole 58 scales 70,170 Connecting shaft 71,171 Shaft 72 threads 76,176 Connecting part 80 Nut 81 indicators 100 Rolling Tool Unit

Claims

1. a base having an insertion hole into which a workpiece is inserted; a plurality of dies arranged around the insertion hole of the base; a rolling tool having a holder having an attachment portion to be attached to a processing device for the workpiece, and a holding portion connected to the attachment portion and holding the rolling tool; Equipped with A rolling tool unit that rolls a thread on the workpiece inserted into the insertion hole, a connecting shaft having a rod-like shaft portion and a connecting portion at one end of the shaft portion that is connected to the base; the mounting portion of the holder is tubular with a through hole formed therethrough, the holding portion of the holder has an inner circumferential surface that is recessed and tapered toward a bottom surface, the holding portion is connected to one end of the mounting portion at the bottom surface side, and the bottom surface is in communication with the through hole of the mounting portion, The connecting shaft is inserted through the through hole, and the connecting portion is disposed in the holding portion and connected to the base. A rolling tool unit characterized by:

2. a screw thread is formed on the other end of the shaft portion of the connecting shaft, A nut is provided to be screwed onto the other end. The rolling tool unit according to claim 1 ,

3. The outer peripheral surface of the base is tapered so that the diameter decreases toward the bottom surface of the holding portion when the base is held by the holding portion. The rolling tool unit according to claim 1 ,

4. The shaft portion and the connecting portion of the connecting shaft are formed separately, the connecting portion has a flange shape that is larger in the radial direction than the shaft portion, a step portion connected to the connecting portion is formed in the insertion hole of the base, The shaft portion is connected to the coupling through the through hole with the coupling portion disposed on the step portion. The rolling tool unit according to claim 1 ,

5. a scale is provided on one of the nut and the mounting portion to indicate the relative rotational position of the nut and the mounting portion; The other of the nut and the mounting portion is provided with an index that indicates the scale.

3. The rolling tool unit according to claim 2, wherein:

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