JPH0333369Y2 - - 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 facing in the axial direction from the distal end surface are arranged circumferentially at intervals on the inner circumferential surface of the chuck cylinder, and the chuck is used for tightening. By rotating the rotary tube, the chuck tube is contracted, particularly by the thinner part of the recess, thereby gripping and holding the cutting tool fitted in the chuck tube.

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.
In the chuck in which a large number of needle rollers 4 are interposed between the chuck tube 2 and the chuck tube 2, the needle rollers 4 spirally revolve at a required helical angle α with respect to the outer peripheral surface of the chuck tube 2 (FIG. 3). Outer surface 2 of cylinder 2
c, a plurality of rows of recesses 5 are provided in the circumferential direction, extending from the distal end surface 2a substantially in the axial direction and at a required intersecting angle β (FIG. 3) with respect to the helical angle α of the needle roller 4. This configuration adopts a configuration in which the

(Example) In FIGS. 1 and 2, the chuck body 1
is a taper shank portion 6 that is removably 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 consists of a straight inner circumferential surface 2b corresponding to the straight shank portion (not shown) of the tool to be gripped, and an outer circumferential surface tapered toward the tip. It has a surface 2c. Reference numeral 3 denotes a tightening rotary tube that is fitted onto the chuck tube 2, and has an inner circumferential surface 3a formed in a tapered shape to correspond to the tapered outer circumferential surface 2c of the chuck tube 2. A large number of needle rollers 4 are interposed between the chuck tube 2 and the chuck tube 2, and the needle rollers 4 revolve helically around the outer peripheral surface of the chuck tube 4.

The outer circumferential surface 2c of the chuck tube 2 has a surface extending from its tip end surface 2a substantially in the axial direction, and at the helical angle α of the needle roller 4, that is, at the time of tightening rotation of the rotary tightening tube 3, as shown in FIG. With respect to the needle roller 4 which rolls at a required angle of inclination α with respect to the generatrix O set on the outer peripheral surface of the chuck tube 2, a recessed portion 5 extending at a required intersection angle β (5° to 30°) is formed. They are arranged at equal intervals in the circumferential direction with a phase difference of 45 degrees. The length of the recess 5 in the axial direction is not limited, but it is preferably a length from the middle of the chuck tube 2 to the tip, as shown in FIG. It is preferable that the tube be formed deeply in the thickness direction of the cylinder, and that its proximal end surface 2d be formed into an arcuate tapered surface in order to exert a reasonable contraction effect.
The needle rollers 4 are of course held by a retainer 8, and are designed to run on the chuck tube 2 by rotating and revolving in a spiral direction.

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 a substantially axial direction from the distal end surface 2a.
are arranged in multiple rows in the circumferential direction,
By rotating the tightening rotary cylinder 3 and tightening the chuck cylinder 2 via the needle roller 4, the opening width d of the recess 5 is contracted by the pressing force of the needle roller 4, and the inner diameter of the chuck cylinder 2 is reduced. This will reduce the diameter. In this case, the thicker the wall of the chuck tube 2 itself, the greater the influence of the pressing force of the needle roller 4 on the tip of the chuck tube. The contraction effect also acts greatly on the aperture width d of No. 5, and the aperture diameter at the tip is also strongly reduced.
It is possible to increase the gripping force (chuck force) on the tool.

In the embodiment shown in FIG.
There is no change in the thickness of the cylinder except for the part where the recess 5 is provided, which has the advantage of increasing rigidity, but since there is a risk that the elastic deformation will be slightly inferior, the 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 cylinder and a deep hole 10b continuous with the slit 10a, are arranged in the circumferential direction, and the thickness of the chuck tube 2 is adjusted so that the chuck tube 2 is easily elastically deformed. It may also be possible to vary the . 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. 6, and a U-shaped cross section as shown in FIG.
Alternatively, the wall thickness of the chuck tube 2 can be varied by forming it in a deep hole shape as shown in FIG.

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 furthermore, as shown in FIG.
is integrally fixed to the chuck main body 1 by bolts 21, and slits 22 are provided at equal intervals in the circumferential direction on the inner cylinder 20a over the entire area or halfway in the inner cylinder 20a. The above-described recess 5 may be provided in the recess 5 .

Furthermore, as shown in FIG. 11, 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, as shown in FIG.
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 influences 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 According to the present invention, the tool gripping force of the collet is greatly improved by the large contractile force shown by the arrow P at the tip of the chuck tube, and the cutting tool can be gripped strongly. I can do it.

(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 part of the chuck cylinder, so that the contraction effect works well, and the diameter of the opening at the tip of the chuck cylinder can be easily reduced, making it possible to grip the tool strongly.

In particular, the thicker the wall of the chuck tube, the more evenly the impact of the pressing force of the needle roller extends to the tip of the chuck tube, making the contraction force stronger. When gripping via the collet, it is possible to grip more strongly without vibration or falling off.

Furthermore, the concave portion provided in the chuck tube in the approximately axial direction is arranged at a required intersecting angle with respect to the needle rollers arranged at a required helical angle (inclination angle), so that the needle rollers are arranged in an intersecting manner. Since the needle roller crosses the recess, there is no possibility that the needle roller will get stuck in the recess or that it will be difficult to roll due to the uneven resistance of the recess. The tightening operation can be performed smoothly and easily.

Furthermore, according to the present invention, the recess formed in 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. Even if a 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 therein, so that the chuck tube is tightly adhered to the cutting tool inserted therein. Therefore, it can also be used for so-called cutting tools with oil holes, in which cutting oil sent into the chuck tube is introduced into an 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 protrude from the inner peripheral surface of the chuck tube, so the cutting debris becomes an obstacle and makes it difficult to insert the tool into the chuck tube. Not at all.

[Brief explanation of the drawing]

Fig. 1 is a partially longitudinal front view showing one embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line - - in Fig. 1, Fig. 3 is an explanatory diagram of the operation of the same main part, and Fig. 4 is an illustration of the same other parts. 5 is a sectional view taken along the line - in FIG. 4, FIGS. 6 to 8 are longitudinal sectional front views of other embodiments, and FIGS. 9 to 12 are The figure is a partially vertical side view of the main part in another embodiment. DESCRIPTION OF SYMBOLS 1... Chuck body, 2, 20, 30, 40... Chuck cylinder, 2a... Its tip surface, 2c... Its outer peripheral surface, 3... Rotating cylinder 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 a chuck in which a large number of needle rollers are interposed between the tightening rotary cylinder and the chuck cylinder and that revolve in a spiral manner at a required helical angle with respect to the outer peripheral surface of the chuck cylinder, the outer periphery of the chuck cylinder is A chuck in which a plurality of rows of concave portions are arranged in a circumferential direction on a surface thereof, the concave portions extending from the distal end surface in a substantially axial direction and at a predetermined intersecting angle with respect to the helical angle of the needle roller.