JPS6247653B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary tool holder for holding a rotary tool, such as a tap.

Various rotary tool holders equipped with safe torque (safety device) type clutch mechanisms have been developed. For example, as shown in FIG. 12 (a conventional view corresponding to the - sectional view in FIG. 1), a holding hole 16' is formed in the drive ring 6, which is a driving rotation member, and a clutch ball 8 is inserted into this holding hole 16'. A clutch groove 17 that engages with the clutch ball 8 is formed in the driven shaft 4, which is a driven side member, so that the ball 8 is biased by a clutch spring 9, a ring cone 7, etc. as shown in FIG. Rotary tool holders with clutch mechanisms have been developed. In such a holder, when a large load is applied to the driven shaft 4, the clutch is disengaged and only the drive ring 6 rotates, leaving the driven shaft 4 at rest. However, at this time, the clutch ball 8 also revolves around the outer circumference of the driven shaft 4, so
Each time the clutch ball 8 passes through each clutch groove 17, it is forced into the clutch groove 17 by the action of the clutch spring 9 (Fig. 1), and a so-called "knock shock" occurs intermittently, which causes the ball to come off. In this case, there are problems such as the occurrence of abrasion, and problems such as severe wear on the edge portion of the clutch groove 17.

The purpose of the present invention is to solve the above-mentioned problems, and the gist thereof is to form a clutch piece holding hole in either one of the driving side rotating member and the driven side rotating member on the same axis. At the same time, the clutch piece is held in this holding hole, a clutch groove that can freely engage with the clutch piece is formed in the other member, and the clutch piece is engaged with the clutch groove by an appropriate biasing means, and the clutch piece, the holding hole, and The clutch groove constitutes a clutch mechanism that disengages the clutch when the resistance torque is greater than the set torque value, and some of the holding holes are formed into long holding holes that are longer in the circumferential direction than the remaining holding holes to increase the holding length. The clutch piece in the hole is made movable in the longitudinal direction of the holding slot as a clutch disengagement/maintenance piece. The present invention will be described above based on the embodiment drawings.

1 and 4 show the first embodiment. First, in FIG. 1, the tap holder is attached to the holder main body 1.
(imaginary line) and a tap collet 2, and the handle (not shown) on the rear end side (opposite the arrow F side) of the main body 1 is connected to the rotating main shaft of the machine tool. The tap collet 2 includes a holding cylinder 3, a driven shaft 4, a clamping tube 5, etc., and also incorporates a one-way rotating clutch mechanism consisting of a drive ring 6, a ring cone 7, a clutch ball 8, a clutch spring 9, etc.

The drive ring 6 has its rear protrusion 6a in the recess 1 of the main body 1.
a, so that it always rotates integrally with the main body 1, and the holding cylinder 3 is fixed to the drive ring 6. A spring adjustment nut 10 is screwed into the inner peripheral threaded portion of the front end of the holding cylinder 3.

The driven shaft 4 fits into the inner circumference of the drive ring 6, and
Torque is transmitted from the drive ring 6 via the balls 8 and the like. The clamping tube 5 is fitted onto the inner circumferential surface of the front end portion of the driven shaft 4 so as to be slidable in the axial direction, and is urged forward by a locking spring 12, and further includes a plurality of locking balls 13 which are freely movable in the radial direction. is provided in the holding hole 15. This lock ball 13 comes into contact with an annular tapered groove 14 formed on the inner peripheral surface of the driven shaft, thereby forming a so-called ball lock type tightening mechanism. The tapered groove 14 is formed to decrease in diameter as it goes forward, and the holding hole 15 is formed so that the lock ball 13 can protrude into the tightening tube 5 to some extent, but the hole diameter on the inner side is, for example, slightly smaller to prevent it from falling off. It's summery. When attaching the tap T, push the tightening tube 5 backward against the spring 12. After inserting the tap T, for example, by releasing your hand from the tightening tube 5, the elastic force of the spring 12 is applied. At the same time, the cam action of the tapered groove 14 pushes the lock ball 13 inward,
Tighten the tap T. Note that the rear end edge of the tap T is formed to have a quadrilateral cross-section, and engages with a hole 4a of the driven shaft 4 having a quadrilateral cross-section.

Clutch ball 8 and clutch disengagement maintenance ball 8
a (FIG. 2) is inserted into a ball holding hole 16 of the drive ring 6 and a holding slot 16a, which will be described later, and is engaged with a clutch groove 17 formed on the outer periphery of the driven shaft 4. The ring cone 7 has its inner cam surface in contact with the outer side of the clutch ball 8, etc.
The clutch ball 8 is biased rearward with a constant pressure by the clutch spring 9, and the clutch ball 8 is pressed inward.

In FIG. 2, arrow A indicates the forward rotational direction of thread cutting, that is, the forward rotational direction, and among the six ball holding holes 16, 16a, three holding elongated holes indicated by 16a extend in the reverse rotational direction B. It is longer in the circumferential direction than the remaining three holding holes indicated by 16. In addition, the three holding holes 16 are located in the clutch groove 1.
7, the holding elongated hole 16a has its forward rotation A direction side portion aligned with the clutch groove 1.
It is now compatible with 7. Note that six clutch grooves 17 are formed at equal intervals in the circumferential direction. Further, the holding elongated hole 16a may extend long in parallel to the circumferential direction, or may be inclined to some extent with respect to the circumferential direction as shown in FIG.

As shown in FIG. 2, the three short holding holes 16 are inclined so that as they go inward, they rotate in the positive direction. That is, the holding hole center line _O2 is inclined with respect to the line R connecting the shaft center _O1 and the ball center so that the inner side is on the forward rotation A direction side.

The set value of the clutch maximum transmission torque is determined by adjusting the amount of compression of the clutch spring 9 using the adjusting nut 10 (Fig. 1). During forward rotation, the ball 8 is forced outward by the cam action of the ball holding hole 16. Taking into consideration the applied force, the clutch spring 9 is adjusted and set to a value that can sufficiently secure the transmission torque required during forward rotation for thread cutting.

When threading a bottom hole, the elastic force of the clutch spring 9 maintains the clutch engaged state, that is, the engaged state of the clutch ball 8 and the clutch groove 17, during forward rotation for thread cutting (rotation in the direction of arrow A). When a large load is applied to the driven shaft 4, such as when the bottom of the hole is reached, the drive ring 6
The clutch ball 8 is twisted in the direction of arrow A, and the clutch ball 8 moves outward against the elastic force of the clutch spring 9 due to the cam action of the holding hole 16, and the clutch is disengaged.

Figure 3 shows the state immediately after the clutch is disengaged, and Figure 4 shows the state after the clutch has been disengaged, when the clutch ball 8 in the short holding hole 16 has rotated to a position corresponding to the clutch groove 17 on the next normal rotation A direction side. Indicates the current state. That is, FIG. 4 shows a state in which the drive ring 6 has been rotated 60 degrees in the forward rotation direction A from the state shown in FIG. 2 with respect to the driven shaft 4. In other words, immediately after the clutch is disengaged, the ball 8 in the short holding hole 16 moves along with the drive ring 6 to the driven shaft 4.
However, the clutch disengagement maintaining ball 8a in the holding elongated hole 16a remains in the driving ring until the drive ring 6 changes from the state shown in FIG. 2 to the state shown in FIG. 6, but rotates together with the drive ring 6 after coming into contact with the edge of the holding elongated hole 16a in the direction of reverse rotation B as shown in FIG. That is, each clutch disengagement maintaining ball 8a rotates in a state closer to the clutch ball 8 on the reverse rotation B direction side than in the state shown in FIG.

Therefore, even if each clutch ball 8 comes to a position corresponding to the clutch groove 17 on the next forward rotation A side as shown in FIG. 4, the clutch disengagement maintaining ball 8a does not come to a position corresponding to the clutch groove 17. , the clutch spring 9 can be maintained in a compressed state through the ring cone 7 (FIG. 1) by the clutch disengagement maintaining ball 8a, that is, the state in which the clutch ball 8 is not pressed down, and the clutch ball 8 is forced into the clutch groove 17. You will not be forced into it. Therefore, there is no "knock shock phenomenon" when the clutch is in the disengaged state, and there is no drop-out phenomenon caused by the shock.

Note that the clutch disengagement maintaining ball 8a is in the clutch groove 1.
When the clutch ball 8 reaches the position corresponding to 7, the remaining clutch ball 8 maintains the compressed state of the clutch spring 9.

During extraction and reverse rotation (rotation in the direction of arrow B), the cam action of the holding hole 16 on the clutch ball 8 is as follows:
Since the action is to push the ball 8 inward, the clutch is always kept in the engaged state and the extraction operation can be performed reliably.

Figure 6 shows the clutch force diagram when rotating in the forward direction, and Figure ₇ shows the clutch force diagram when _rotating in the reverse direction. From groove 17 to clutch ball 8
, Y ₁ and Y ₂ are component forces in the direction orthogonal to the holding hole 16 of X ₁ and X ₂ , respectively, and Z ₁ and Z ₂ are X ₁ and
This is the component force in the direction parallel to the holding hole 16 of _X2 . _Y1 ,
_Y2 has the opposite direction and the same magnitude as the rotational force applied from the drive ring 6 to the clutch ball 8. Z ₁ , Z ₂
is a force that tends to push the clutch ball 8 outward along the holding hole 16. That is, since a relationship such as Z ₁ >> _{Z 2} occurs, a one-way rotation clutch mechanism can be constructed in which the clutch disengagement action can occur only during forward rotation.

8 and 9 show a second embodiment. In FIGS. 8 and 9, a holding hole 16 and a holding elongated hole 16a for holding the clutch ball 8 and the clutch disengagement maintaining ball 8a are connected to the driven shaft 4. A clutch groove 17 is formed in the drive ring 6 and is capable of engaging the clutch ball 8 and the like. The clutch spring 9 is compressed within the driven shaft 4, and presses the clutch ball 8 and the like outward with a constant pressure via the presser ball 20. Reference numeral 21 denotes a clutch spring adjusting nut, which is screwed into the inner circumferential threaded portion of the rear end of the driven shaft 4. The presser ball 20 is fitted into the driven shaft 4 so as to be movable in the axial direction. 23 is a lock bolt that tightens the tap T.

The holding hole 16 (FIG. 9) is inclined so as to be in the forward rotation A direction as it goes inward.

The retaining slot 16a is longer in the circumferential direction than the retaining hole 16, and the clutch-off retaining ball 8
a is relatively movable in the inner circumferential direction within the holding elongated hole 16a. Further, the holding elongated hole 16a is formed so as to extend in the forward rotation A direction from a position corresponding to the clutch groove 17 in the clutch engaged state shown in FIG.

When threading a bottom hole using the tap collet shown in Figs. 8 and 9, when threading is rotated forward (rotating in the direction of arrow A), the elastic force of the clutch spring 9 causes the clutch to be in the engaged state, that is, the clutch ball 8 The engaged state of the clutch groove 17 is maintained. When it reaches the bottom of the hole and a large load is applied to the tap T,
When the drive ring 6 is twisted in the direction of arrow A relative to the driven shaft 4, the clutch ball 8 is pushed inward along the holding hole 16 by the cam action of the holding hole 16, and the clutch is disengaged.

Clutch disengagement maintenance ball 8 after the clutch disengages
The clutch disengagement maintaining action by a and the like is basically the same as in the first embodiment described above. This makes it possible to prevent the "strike shock phenomenon" in the clutch disengaged state.

When the extraction is rotated in the reverse direction (rotating in the direction of arrow B), the cam action of the holding hole 16 acts to push the ball 8 outward, so the clutch is always kept in the engaged state and the extraction operation can be performed reliably. I can do it.

10 and 11 show the third embodiment,
10 and 11, an annular flange 24 projecting outward is integrally formed on the driven shaft 4, and a clutch ball holding hole 1 is formed in this flange 24.
6 and a holding elongated hole 16a are formed. A clutch groove 17 that can freely engage with the clutch ball 8 and the clutch disengagement maintaining ball 8a is formed on the front surface of the drive ring 6, and the clutch ball 8 and the clutch disengaging maintaining ball 8a are moved rearwardly through the annular plate 26 by the clutch spring 9. is being energized.

As shown in FIG. 11, the holding hole 16 is inclined toward the forward rotation A direction as it goes forward.

The holding elongated hole 16a extends long in the forward rotation A direction from a position corresponding to the clutch groove 17 in the engaged state of FIG. 11.

When threading a bottom hole using the tap collet shown in Figs. 10 and 11, the clutch spring 9
Due to the elastic force of the clutch ball 8 and clutch groove 1
Maintain the meshing condition of 7. When the tap T reaches the bottom of the hole and a large load is applied, the drive ring 6 twists in the direction of arrow A with respect to the driven shaft 4, causing the holding hole 16 to twist.
The clutch ball 8 is pushed forward by the cam action, and the clutch is disengaged.

Clutch disengagement maintenance ball 8 after the clutch disengages
The clutch disengagement maintaining action by a and the like is basically the same as in the first embodiment described above, thereby making it possible to prevent the "knock shock phenomenon" in the clutch disengaged state.

During extraction rotation (rotation in the direction of arrow B), the cam action of the holding hole 16 acts to push the ball 8 backward, so that the clutch is always kept in the engaged state and the extraction operation can be performed reliably.

In the first to third embodiments described above, a clutch roller or the like may be used instead of the clutch ball 8.

Further, the number of holding elongated holes 16a may be one or two, or even four or more.

Alternatively, the short holding hole 16 may be formed so as not to be inclined with respect to the radial straight line R, as shown in FIG. 12, so that the clutch disengagement action can occur both during forward and reverse rotation.

As explained above, in the present invention, a clutch piece holding hole is formed in one of the driving side rotating member and the driven side rotating member which are coaxially centered, and the clutch piece is held in this holding hole. , a clutch groove that can freely engage with the clutch piece is formed in the other member, and the clutch piece is engaged with the clutch groove by an appropriate biasing means, and when the resistance torque is greater than the set torque value by the clutch piece, the holding hole, and the clutch groove. A clutch mechanism is constructed in which the clutch is disengaged when the clutch is disengaged, and some of the retaining holes are formed into retaining long holes that are longer in the circumferential direction than the remaining retaining holes, and the clutch piece in the retaining long hole is held as a clutch disengagement retaining piece. Since it is characterized by being movable in the length direction of the elongated hole, it has the following advantages.

(1) When an excessive load is applied to a tool such as a tap and the clutch becomes disengaged, the clutch disengagement retaining piece,
For example, the clutch disengaged state can be reliably maintained by the action of the clutch disengagement maintaining ball 8a.
The conventional "tapping shock phenomenon" does not occur, and it is possible to prevent taps from coming off due to the shock.

(2) Preventing the "knock shot phenomenon" improves tap setting accuracy and also helps prevent tap wear. Furthermore, since the clutch groove 17 has the effect of preventing wear, there is no fear that the set value of the maximum transmission torque will decrease due to wear of the clutch groove 17.

(3) Since the "knock shock phenomenon" is eliminated, for example, the quadrilateral portion of the rear end of the tap that engages with the quadrilateral hole 4a in FIG. T-shirts, etc. can always be smoothly attached and detached.

(4) If the clutch mechanism is a one-way rotating clutch mechanism that can disengage the clutch only when rotating in one direction, the clutch will become disengaged when, for example, a tap T is used to thread a hole in the bottom. By setting the direction of rotation for thread cutting to be the forward rotation direction, the clutch will be reliably disengaged when the bottom of the hole is reached or abnormal torque is generated, ensuring sufficient safety, and there is no need to worry about the clutch disengaging unnecessarily during reverse rotation for extraction. This improves work efficiency.

Of course, even if a rotary tool such as a drill is attached, sufficient safety can be ensured.

[Brief explanation of the drawing]

1 to 5 show a first embodiment of a rotary tool holder to which the present invention is applied, in which FIG. 1 is a longitudinal sectional side view, FIG. , FIG. 4 is a cross-sectional equivalent view of FIG. 1 in the clutch disengaged state, FIG. 5 is a developed partial view in the direction of arrows in FIG. 2, FIGS. FIG. 8 is a longitudinal sectional side view of the second embodiment, FIG. 9 is a - sectional view of FIG. 8, FIG. 10 is a longitudinal sectional side view of the third embodiment, and FIG. The developed view, FIG. 12, shows a conventional example and is a sectional view corresponding to FIG. 2. 4... Driven shaft (an example of a driven rotating member), 6... Drive ring (an example of a driving rotating member), 8... Clutch ball (an example of a clutch piece), 8a... Clutch disengagement maintenance ball (clutch disengagement (Example of maintenance piece), 9...Clutch spring (Example of biasing means), 16...Retention hole, 1
6a... Holding slot, 17... Clutch groove.

Claims (1)

[Scope of Claims] 1 A clutch piece holding hole is formed in one of the driving rotating member and the driven rotating member which are coaxially arranged, and the clutch piece is held in this holding hole, and the other member is A clutch groove that can freely engage with the clutch piece is formed in the clutch groove, and the clutch piece is engaged with the clutch groove by an appropriate biasing means, and the clutch piece, the holding hole, and the clutch groove disengage the clutch when the resistance torque is greater than a set torque value. The clutch mechanism is configured such that some of the holding holes are formed into holding long holes that are longer in the circumferential direction than the remaining holding holes, and the clutch piece in the holding long hole is used as a clutch disengagement holding piece to maintain the length of the holding long hole. A rotary tool holder characterized by being movable in a direction. 2 As a clutch mechanism, an inclined surface is formed on one end surface of the holding hole in the tool rotation direction to abut the clutch piece and pressurize it into the clutch groove when the drive rotating member rotates in reverse, thereby preventing the clutch from breaking during reverse rotation. The rotating tool holder according to claim 1, characterized in that it is a one-way rotating clutch.