JPS6113933B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tap holder used to attach a tap to the main spindle of a general-purpose machine tool, a special-purpose machine tool, a machining center, etc. The present invention relates to an improvement of a tap holder equipped with an axial floating mechanism that corrects the

Conventionally, the method of transmitting rotational torque in a tap holder with a built-in axial floating mechanism has been to simply transmit the rotational torque linearly from the rear end of the main body to the tap side. In addition, when attaching a clutch mechanism such as a torque limiter to this tap holder, most of the clutch mechanisms are installed on the outer periphery of the tap gripping part and have a large outer diameter, and when attached to a multi-axis head, female threads with a small pitch between adjacent screw holes are installed. This was inconvenient when machining an internal thread or when machining a female thread in a position close to a wall. Furthermore, vibrations generated during clutch operation are easily transmitted to the taps, which may adversely affect the thread accuracy of the machined internal thread. Although some holders have a clutch mechanism built into the holder body, the outside diameter of the holder is still large and the above-mentioned difficulties cannot be avoided. There is also a clutch unit interposed between the machine spindle and the tap holder, but in this case the overall length is long and the runout has a negative effect on screw accuracy.

In order to solve the above problems of the conventional tap holder, the present invention improves the means for transmitting torque from the holder body to the tap, and is a transmission member that transmits rotational torque from the holder body to the spindle that grips the tap. The object of the present invention is to provide a tap holder which is fitted into the rear end opening of a cylindrical body and transmits rotational torque from the rear of the body to the tap through the inside.

Another object of the present invention is to provide a tap holder that can hold a large tap while reducing the outer diameter of the holder body by employing the above-mentioned torque transmission means.

Still another object of the present invention is to provide a tap holder in which the components of the holder body, transmission member, and clutch mechanism can be easily shared.

In order to achieve the above object, the tap holder of the present invention includes a cylindrical body that is rotated in conjunction with the machine main shaft, and a spindle that is slidably inserted into the body via an axial floating mechanism. , a tap grip provided on the front end protrusion of the spindle is fitted into the rear end opening of the main body and engages with the rear end of the spindle so as to be displaceable in the axial direction relative to the rear end of the spindle, thereby rotating the main body. A transmission member that transmits force to the spindle.

Hereinafter, one embodiment of the present invention will be described based on the drawings. Reference numeral 1 denotes a holder main body, which has a cylindrical shape and has a lock nut 3 screwed into a threaded portion 2 carved on the outer periphery of the front half. Reference numeral 4 denotes a spindle that is slidably inserted into the main body 1, and is formed into a bottomed cylindrical body having a bottom portion 5 at the rear end, and as described later, a spring fitting is formed with the rear portion having a slightly smaller diameter. A single compression coil spring 7 externally fitted to the portion 6 is fitted into the main body 1 so as to be movable in the axial direction by an axial floating mechanism that acts on both the extension side and the contraction side. Reference numeral 8 indicates a collet fitted to the spindle 4, 9 indicates a drive pin that interlocks the collet 8 to the spindle 4, and 10 indicates a ball 11 in the front end opening of the spindle 4.
A clamp nut fitted freely through the
It is provided to screw onto the collet 8 and to fix and hold the tap T inserted into the collet 8 on the spindle 4.

Reference numeral 12 denotes a driver for transmitting the rotational force of the main body 1 to the spindle 4, which includes a disk 13 fitted to the rear end opening of the main body 1 using a retaining ring 16, and a driver provided protruding from one side of the disk 13. It consists of a square shaft 14 with a square shape and a shaft 15 protruding from the other side, and the square shaft 14 is inserted into a square hole 17 formed in the bottom 5 of the spindle 4 so as to be relatively slidable and engaged with the spindle 4. do. On the other hand, a torque limiter 18 is attached to the shaft 15, so that the rotational force of the main body 1 is transmitted to the driver 12 via the torque limiter 18, and the rotational force is transmitted to the spindle 4 via the square shaft 14.

The torque limiter 18 includes a retainer 19 which is a cylindrical body with a bottom, a pole 20, a guide bush 21 which is loosely fitted to the shaft 15, a plurality of disc springs 22 which are alternately oriented and arranged one on top of the other, and a spring pressure spring. Adjusting nut 23 and disk 1 of driver 12
The ball engaging groove 24 is formed of three ball engaging grooves 24 extending in an arc shape and recessed in the side surface of the ball 3 with a phase difference of 120 degrees. The retainer 19 has a driver 12 at its bottom, as clearly shown in FIG.
an aperture 25 through which the shaft 15 is inserted, and an aperture 25 that is provided concentrically with the aperture 25 with a phase difference of 120 degrees.
Two ball accommodation holes 26 are provided, and each accommodation hole 2
6 is a hole 2 through a notch 27 extending in the radial direction.
It is connected to 5. Further, a pair of transmission protrusions 28 that engage with a pair of transmission notches 30 provided at the rear end of the main body 1 are integrally provided at the end of the retainer 19 on the side having the bottom, and the opposite At the side end is a set screw 31 for the spring pressure adjustment nut 23 (see Figure 2).
A recess 29 is provided for inserting the.

A ball 20 is inserted into each accommodation hole 26 of the retainer 19.
is accommodated in an idling state, and the retainer 19 is fitted to the shaft 15 so that each ball 20 engages with the engagement groove 24 of the driver 12, and then the guide bush 2 is fitted.
1. After fitting the disc spring 22 onto the shaft 15, the spring pressure adjusting nut 23 is screwed onto the threaded portion 15a of the shaft 15, thereby constructing the torque limiter 18 which is integrated with the driver 12. In addition, the spring pressure adjustment nut 23
is set screw 3 when tightened to the specified position.
1 to fix it to the shaft 15.

As described above, if the torque limiter 18 is built into the screwdriver 12, if an overload is applied to the tap T during screw tapping, the ball 20
The engagement groove 24 is disengaged from the engagement groove 24 against the spring pressure of the disc spring 22, and the transmission of rotational torque from the main body 1 to the driver 12 is interrupted, thereby preventing the tap T from breaking.

Note that the torque limiter 18 is not incorporated into the driver 12, and the rotational force of the main body 1 is directly applied to the driver 1.
2 to the spindle 4, a driver 12a without a shaft 15 is used, as shown in FIGS. 5 and 6. driver 12
An engagement groove 33 for the drive key 32 is provided on the side surface of the disk 13 in a, and the drive key 32 is attached to the driver 12a with a screw 34, and as shown in FIG. In a state where it is engaged with the transmission notch 30 at the rear end of the main body 1, it is fitted into the rear end opening of the main body 1 using the retaining ring 16 like the driver 12.

Next, an explanation will be given of the axial floating mechanism in which the single compression coil spring 7 described above acts on both the extension side and the contraction side.

The compression coil spring 7 is held between a first retaining ring 35 and a second retaining ring 36 that are movably fitted to both ends of the spring fitting portion 6 of the spindle 4 . As will be described later, the first retaining ring 35 only needs to be movable in the axial direction along the spring fitting part 6, so it may be either a complete ring-shaped retaining ring or a partially open C-shaped concentric retaining ring. However, since the second retaining ring 36 needs to be elastically deformed in the radial direction, a C-shaped concentric retaining ring with a partially open opening is used. First stop shaft 35
is locked to a locking step 37 provided at the base end of the spring fitting portion 6, and is also locked to a locking step 38 provided on the inner wall of the cylindrical hole of the main body 1. . Further, the second retaining ring 36 is engaged with a flange 39 provided at the tip of the spring fitting section 6, and is also engaged with a retaining ring 40 fitted into the inner wall of the cylindrical hole of the main body 1. The second retaining ring 36 is fitted into an annular groove 41 provided in the spindle 4 adjacent to the collar 39, and the spring fitting part 6 is inserted from the bottom of the annular groove 41.
The spring fitting part 6 can be moved to the outer periphery of the spring fitting part 6 by climbing over an inclined wall surface 42 extending to the outer periphery of the spring fitting part 6. The spindle 4 has a spring fitting part 6 and a collar part 3 so that it can be moved in the axial direction by passing through the retaining ring 40.
The outer diameter of the retaining ring 9 is slightly smaller than the inner diameter of the retaining ring 40. In the figure, 43 is a keyway provided on the outer periphery of the main body 1.

As shown in FIG. 2, the tap holder having the above structure can be wedged with the tool exchange holder 44 via a key 45, and the tool exchange holder 44 can be attached to the machine main shaft (not shown), or the main body 1 can be attached directly to the machine main shaft. Use it by attaching it to. The rotation of the machine spindle is transmitted from the tool exchange holder 44 to the main body 1 via the key 45 or directly,
The torque is transmitted from the main body 1 to the driver 12 via the torque limiter 18 at the rear end, and further transmitted to the spindle 4 via the square shaft 14 of the driver 12 to rotate the tap T. In this state, the main shaft of the machine moves in the axial direction and feeds the tap T to perform the tapping operation.

When the tap T bites into the prepared hole 47 of the workpiece 46 as shown in FIG. 2, the spindle 4 is displaced toward the contraction side, but at this time, the second retaining ring 36
Since it is locked by the retaining ring 40 of the main body 1 and prevented from moving in the axial direction, the spindle is slightly elastically deformed outward in the radial direction as shown in FIGS. 7 and 8. Climb onto the inclined wall 42 of No. 4,
Furthermore, it moves over the inclined wall surface 42 to the outer periphery of the spring fitting part 6. Then, the biting force of the tap T increases due to the resistance force when climbing over the inclined wall surface 42, and the biting of the tap into the prepared hole 47 is performed reliably. When the second retaining ring 36 moves to the outer periphery of the spring fitting part 6, since the outer peripheral surface of the spring fitting part 6 has been ground, the resistance to the second retaining ring 36 moving in the axial direction is reduced and the movement is smooth. Performs floating function. When the spindle 4 moves toward the contraction side as described above, the first retaining ring 35 is retained by the retaining step 37 and moves in the axial direction together with the spindle 4, so that the first retaining ring 35 is retained between the retaining rings 35 and 36. As the distance narrows, the coil spring 7 is compressed, and the spring pressure allows the spindle 4 to return smoothly and reliably to its original position.

Also, when the spindle 4 is displaced to the extension side,
The first retaining ring 35 is retained by the retaining step 38 of the main body 1 and is prevented from moving in the axial direction, and the second retaining ring 36
is locked to the collar 39 and moves in the axial direction together with the spindle 4, so that the spacing between the retaining rings 35 and 36 is narrowed and the coil spring 7 is compressed.

As mentioned above, one compression coil spring 7 acts on both the extension side and the contraction side, and performs an effective floating function.

As detailed above, in the tap holder of the present invention, the transmission member that transmits rotational torque from the holder body to the spindle that grips the tap is fitted into the rear end opening of the cylindrical body, and is transmitted from the rear of the body through the inside. By transmitting rotational torque to the tap and incorporating a clutch mechanism such as a torque limiter into the transmission member, the transmission member and clutch mechanism are made to be separate and independent from the main body, so the outer diameter of the holder main body can be reduced. It can hold a large tap, which is very convenient for use and handling. Moreover, there is an advantage that the parts of the holder main body, transmission member, and clutch mechanism can be easily used in common for a certain range of tap sizes.

Furthermore, if a retaining ring is used to fit the transmission member and clutch mechanism, which are separated and independent from the main body, into the rear end opening of the cylindrical main body, as in the embodiment, the connection structure and the attachment/detachment operation will be simplified. In addition, since there is a slight gap in the axial direction between the transmission member and the main body, it is possible to effectively prevent the vibration generated during the operation of the clutch mechanism from being directly transmitted to the main body and spindle, which improves thread accuracy. No adverse effects.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of the tap holder according to the present invention, Fig. 2 is a longitudinal sectional front view of the main part in the same state of use, and Fig. 3 is a perspective view of the driver (transmission member).
FIG. 4 is a perspective view of a retainer that forms the main body of the torque limiter, FIG. 5 is a perspective view showing another embodiment of the driver, FIG. Figure 7 is an explanatory diagram of the axial floating mechanism when the spindle moves to the contraction side, and Figure 8 is A-A in Figure 7.
It is a sectional view along a line. 1... Main body, 4... Spindle, 8... Collet, 12, 12a... Driver, 13... Disk, 14... Square shaft, 16... Retaining ring, 18... Torque limiter, 19... Retainer, 20 ... Ball, 21 ... Guide pushpiece, 22 ... Disc spring,
23...Pressure adjustment nut, 24...Engagement groove, 28...
...Transmission protrusion, 30...Transmission notch, T...tap.

Claims (1)

[Claims] 1. A cylindrical main body that is rotated in conjunction with a main shaft of the machine, a spindle that is slidably fitted into the main body via an axial and floating mechanism,
A tap grip provided on a protrusion at the front end of the spindle is fitted into an opening at the rear end of the main body, and engages with the rear end of the spindle so as to be able to be displaced in the axial direction relative to the main body, thereby absorbing the rotational force of the main body. and a transmission member for transmitting the power to the spindle. 2. The tap holder according to claim 1, wherein a torque limiter is attached to the transmission member. 3. The transmission member is composed of a disc that fits into the rear end opening of the main body, and a square shaft protruding from the side surface of the disc, and the square shaft is axially positioned relative to a square hole provided at the rear end of the spindle. 3. The tap holder according to claim 1 or 2, wherein the tap holder is engaged so as to be displaceable in a direction. 4. The tap holder according to any one of claims 1 to 3, wherein the transmission member is fitted into the rear end opening of the main body using a retaining ring.