JPH039927Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of application of the invention) The invention relates to a chuck for gripping tools such as drills and end mills, and in particular, the outer peripheral surface of the chuck body has a tapered shape on the tip side. A chuck tube protrudes from the chuck tube, and a rotary tightening tube having a tapered inner circumferential surface is fitted onto the chuck tube. This invention relates to a chuck that is equipped with a large number of needle rollers that spirally revolve around the outer peripheral surface of a cylinder.

(Prior art) In this type of chuck, one has been proposed in which a large number of recesses are arranged circumferentially at intervals on the inner circumferential surface of the chuck cylinder, facing in the axial direction from the distal end surface, and are used for tightening. By rotating the rotary cylinder, the chuck cylinder is contracted, particularly by the thinned portion of the recess, and thereby the cutting tool fitted in the chuck cylinder is gripped and held.

However, when a recess is provided in the inner circumferential surface of the chuck tube in this manner, there are the following difficulties.

First, by providing this recess on the inner circumferential surface of the chuck cylinder, the corner edge of the recess bites into the tool due to circumferential cutting resistance applied to the cutting tool held on the inner circumferential surface of the cylinder. The problem is that the tool is damaged, and many fine irregularities occur on the surface of the tool during long-term use, making it impossible to grip the tool accurately.

In addition, if the cutting tool has an oil hole, that is, if the cutting tool is of a type in which the cutting oil sent into the chuck tube is introduced into the oil hole provided in the tool body and released from the tip of the cutting blade, Due to the presence of the recess between the chuck tube and the cutting tool, cutting oil leaks out from the recess, so it cannot be used in this type of cutting tool.

Furthermore, during the cutting process, cutting debris enters the recess between the chuck tube and the cutting tool, protrudes from the inner peripheral surface of the chuck tube, and becomes an obstacle when inserting the cutting tool into the chuck tube. There was a risk that the insertion would be hindered.

(Problems to be Solved by the Invention) The present invention attempts to overcome the various difficulties described above and provide a chuck with excellent gripping force.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes a chuck tube 2 protruding from the tip side of the chuck body 1 and having a tapered outer peripheral surface. A rotary tightening tube 3 having a tapered inner peripheral surface is fitted onto the chuck tube, and the rotary tightening tube 3 is fitted onto the chuck tube.
A large number of needle rollers 4 are provided between the chuck tube 2 and the chuck tube 2, and the needle rollers 4 spirally revolve around the outer peripheral surface of the chuck tube 2.
In the chuck in which the chuck is interposed, a recess 5 is formed in the outer circumferential surface 2c of the chuck cylinder 2 in the circumferential direction from the distal end surface 2a of the chuck, which faces approximately in the axial direction and has a length that does not impede the rolling of the needle roller 4. They are arranged in a plurality of rows, and the inner circumferential surface 2b' of the tip of the chuck tube where the recesses 5 are formed is formed into a flat surface.

(Example) In FIGS. 1 and 2, the chuck body 1
is a tapered shank portion 6 that is detachably attached to a spindle head (not shown) of a machining center, etc.
A chuck positioning flange 7 is concentrically connected to the large-diameter end of the tapered shank 6, and a chuck positioning flange 7 is concentrically protruded from the flange 7 to the distal end of the chuck main body 1. The chuck tube 2 has a straight inner circumferential surface 2b that corresponds to the straight shank or straight collet of the tool to be gripped, and an outer circumferential surface 2c that is tapered toward the tip. It is equipped with Reference numeral 3 denotes a rotating tightening tube fitted onto the chuck tube 2, and the tapered outer circumferential surface 2 of the chuck tube 2.
A large number of needle rollers are provided between the rotary cylinder 3 and the chuck cylinder 2 and revolve in a spiral manner with respect to the outer peripheral surface of the chuck cylinder 4. 4... is interposed.

The outer circumferential surface 2c of the chuck tube 2 has a recess 5 oriented in the axial direction from the tip end surface 2a and having a length l that does not impede the rolling of the needle roller 4, specifically as shown in FIG. In the position where the chuck tube 2 is relaxed, the tip portion 4' of the needle roller 4 does not overlap the recess 5, or even if it overlaps, the tip portion 4' separates from the recess 5 by the tightening operation of the chuck tube 2. Slit-shaped recesses 5 having a length l in the axial direction are arranged at equal intervals in the circumferential direction with a phase difference of 45 degrees. In this case, the concave portion 5 is formed as deep as possible in the thickness direction of the chuck tube to the extent that plastic deformation does not occur during contraction, and the proximal end surface 2d is formed into an arcuate tapered surface to exert a reasonable contraction effect. Preferable from above. Further, the inner circumferential surface 2b' of the tip of the chuck tube where the recess 5 is formed is not formed with any recess or annular groove, but is formed as a flat surface. In addition, the above needle roller 4...
is naturally held by the retainer 8, and
The four axes of each roller are arranged so as to be appropriately inclined with respect to the generatrix set on the tapered outer circumferential surface 2c of the chuck tube 2, so that the rollers revolve in a helical direction while rotating with respect to the chuck tube 2. The chuck tube 2 is elastically deformed and contracted by the climbing motion, thereby gripping and holding the tool.

Reference numeral 9 in FIG. 1 indicates a stopper for regulating the position of the inner end of the tool inserted into the chuck tube 2.

In the present invention, a recess 5 is formed on the outer circumferential surface 2c of the chuck tube 2 in the axial direction from the distal end surface 2a.
are arranged in multiple rows in the circumferential direction,
By rotating the tightening rotary tube 3 and tightening the chuck tube 2 via the needle roller 4, the part to which the pressing force of the needle roller 4 is directly applied is affected by the elastic deformation of the chuck tube 2 itself and the needle roller. The opening width d of the recess 5 is reduced in the vicinity of the tip, to which the pressing force of 4 is not directly applied, under the influence of the pressing force, thereby reducing the opening diameter of the tip of the chuck cylinder. In this case, the thicker the chuck tube 2 itself is, the greater the influence of the pressing force of the needle roller 4 on the tip of the chuck tube, which causes a greater contraction effect on the opening width d of the recess 5, and the tool It is possible to increase the gripping force (chuck force) against the object.

In the embodiment shown in FIG.
There is no change in the wall thickness of the cylinder other than the recess 5, which has the advantage of increasing rigidity, but it may be slightly inferior in terms of elastic deformation.
As shown in the figure, multiple rows of chuck grooves 10 extending in the axial direction, each consisting of a slit 10a opening on the inner circumferential surface of the chuck cylinder and a deep hole 10b continuous with the slit 10a, are arranged in the circumferential direction, so that the chuck cylinder 2 is elastically deformed. The thickness of the cylinder may be varied to make it easier. Note that the chuck grooves 10 may be provided continuously and on the same line as the recessed portion 5, or may be provided alternately in the circumferential direction.

Furthermore, the chuck groove 10 has a U-shaped cross section as shown in FIG. 5, and a U-shaped cross section as shown in FIG.
Alternatively, as shown in FIG. 7, the chuck tube 2 may be formed in a deep hole shape so that the wall thickness of the chuck tube 2 varies.

Furthermore, as shown in FIG.
, an inner cylinder 20 extending integrally with the chuck body 1
a, and an outer cylinder 20b, which is separate from the inner cylinder and is fitted onto the outer peripheral surface of the inner cylinder in a shrink fit direction and is integrally fixed to the chuck body 1, The above-mentioned recess 5 may be provided on the outer circumferential surface of the tip end of the inner and outer cylinders, and as shown in FIG. The above-mentioned recess 5 is provided on the outer circumferential surface of the tip of the chuck tube 30, which is integrally fixed and has slits 22 provided in the inner tube 20a at equal intervals in the circumferential direction over substantially the entire axial direction or halfway up the inner tube 20a. It may be hot.

Furthermore, as shown in FIG. 10, a chuck tube 40 is integrally provided at the center of the chuck body 1, and a required interval 41 is provided on the outer circumferential side of the chuck tube 40.
A regulating ring 42 is provided coaxially with the chuck tube 40.
Attach multiple bolts and nuts 43 to the chuck body 1.
This chuck tube 40 is integrally protruded by means such as
The chuck has a structure in which a rotary tightening cylinder 3 is inserted into the gap 41 between the inner and outer peripheries of the tightening cylinder 3 and is rotatably fitted by needle rollers 4 and 44 which revolve in a spiral manner. The above-described recess 5 may be provided on the outer circumferential surface of the tip of the tube 40.

Furthermore, the recess 5 does not necessarily need to be provided precisely in the axial direction of the chuck tube 2, but may be provided at an angle slightly inclined to the axis of the chuck tube 2, for example, at an inclination angle α of about 30° in the left and right directions, as shown in FIG. Even if the recess 5 is provided within the range, the operation will not change in any way.

Furthermore, as shown in FIG. 12, the chuck tube 2
When gripping the cutting tool 13 with the straight collet 12 interposed between the chuck tube 2 and the straight collet 12, especially when the cutting tool 13 has a small diameter and a short shank length, The gripping force of the tip portion (the portion where the recess 5 is formed) directly affects the tool gripping force of the collet 12. The gap error d ₁ between the chuck tube 2 and the collet 12 and the collet 12
The cutting tool 13 must be gripped by absorbing the total gap amount (d ₁ + d ₂ ) of the gap error d ₂ between After absorption, it will be born for the first time. In this regard, according to the present invention, the tool gripping force of the collet is significantly improved by the large contractile force shown by the arrow P at the tip of the chuck cylinder, and the cutting tool can be gripped strongly.

(Operations and Effects) According to the present invention, when the opening width of the recess provided on the outer peripheral surface of the tip of the chuck tube contracts under the influence of the pressing force of the needle roller, the recess itself is formed as deep as possible. As a result, there is almost no resistance from the thick wall of the recessed part of the chuck cylinder, so the contraction effect works well, and the diameter of the opening at the tip of the chuck cylinder can be easily reduced, allowing the tool to be gripped strongly. can.

In particular, the thicker the wall of the chuck tube, the more the pressing force of the needle roller reaches the tip of the chuck tube, making the contraction force stronger. If you hold it by hand, you can grip it more strongly without it vibrating or falling off.

Furthermore, the length of the recess provided in the axial direction of the chuck tube is such that it does not interfere with the rolling of the needle roller, so that the tightening operation of the rotary tightening tube can be performed easily and quickly. I can do it.

Further, according to the present invention, the recess formed at the tip of the chuck tube is formed on the outer circumferential surface of the chuck tube, and the inner circumferential surface is formed as a flat surface, so that the cutting tool can be gripped by the inner circumferential surface of the chuck tube. Furthermore, even if a strong circumferential cutting force is applied, the tool surface will not be damaged, and the tool can be gripped accurately and reliably for a long period of time.

Furthermore, according to the present invention, since the inner circumferential surface of the chuck tube is formed into a flat surface, there is no gap between the chuck tube and the cutting tool inserted into the chuck tube, and the cutting tool is strong. Because of the close contact, it can also be used in so-called cutting tools with oil holes, where the cutting oil sent into the chuck tube is introduced into the oil hole provided in the tool body and released from the tip of the cutting blade.

Furthermore, according to the present invention, cutting debris does not naturally enter between the inner circumferential surface of the chuck tube and the cutting tool, so the cutting debris does not become an obstacle when inserting the tool into the chuck tube. It's not that difficult.

[Brief explanation of drawings]

Fig. 1 is a partially longitudinal front view showing one embodiment of the present invention, Fig. 2 is a sectional view taken along the line - - in Fig. 1, and Fig. 3 is a partially longitudinal front view showing the main parts of another embodiment of the present invention. , FIG. 4 is a sectional view taken along the line - in FIG. 3, FIGS. 5 to 7 are vertical sectional front views of other embodiments, and FIGS. 8 to 12 are main parts of other embodiments. FIG. 1... Chuck body, 2, 20, 30, 40...
...chuck tube, 2a...its tip surface, 2b'...inner circumferential surface of chuck tip, 2c...its outer circumferential surface, 3
...Rotary tube for tightening, 4...Needle roller, 5...
...concavity.

Claims (1)

[Scope of utility model registration request] A chuck tube having a tapered outer circumferential surface is protruded from the tip side of the chuck body, and a rotary tightening tube having a tapered inner circumferential surface is fitted onto the chuck tube, and In the chuck, in which a large number of needle rollers are interposed between the tightening rotary cylinder and the chuck cylinder, and which revolve in a spiral manner with respect to the outer circumferential surface of the chuck cylinder, the chuck is attached to the outer circumferential surface of the chuck cylinder from its tip surface. A plurality of rows of recesses facing approximately in the axial direction and having a length that does not impede the rolling of the needle roller are arranged in the circumferential direction, and the inner peripheral surface of the tip of the chuck cylinder in which the recesses are formed. is a chuck formed on a flat surface.