JPH0333368Y2 - - 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, by simply providing a recess on the inner circumferential surface of such a chuck tube, sufficient tightening force can be obtained due to the resistance of the thick wall part (including the recess), especially at the tip of the needle roller where no load is applied. The clamping force is insufficient, and as a result, the clamping force is insufficient to grip tools that are subject to strong cutting resistance, such as end mills, without vibration.

(Problem to be solved by the invention) As mentioned above, the reason why the clamping force of the chuck tube is insufficient is because it receives resistance from the thick wall of the chuck tube itself. Therefore, the present invention solves this problem. It is an attempt to overcome the difficulties inherent in the prior art by creating a structure that is not subject to the resistance of the thick portion.

(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). The cylinder 2 is provided with a split groove 5 which extends from the distal end surface 2a in the axial direction and at a required intersection angle β (FIG. 3) with respect to the needle roller 4 to the middle of the chuck cylinder and penetrates inside and outside the chuck cylinder. The structure adopts a structure in which a plurality of rows are arranged in the circumferential direction.

(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 chuck tube 2 is provided with an outer periphery of the chuck tube 2 which is oriented in the axial direction from its tip surface 2a, and when the helical angle α of the needle roller 4 is set, that is, when the rotary tightening tube 3 is rotated for tightening, as shown in FIG. A needle roller 4 that rolls at a required inclination angle α with respect to the generatrix O set on the surface is provided with a split groove 5 extending at a required intersection angle β (5° to 30°) in the circumferential direction. They are arranged at equal intervals with a phase difference of °. As shown in FIG. 1, the length of the split groove 5 in the axial direction is from the middle of the chuck tube 2 to slightly the tip, and the base end surface 2d of the split groove 5 is the length of the chuck tube outer circumferential surface 2c.
It is preferable to provide a tapered shape toward the proximal end toward the inner circumferential surface 2d. The above needle roller 4...
is naturally held by the retainer 8, and the chuck tube 2
It is supposed to rotate on its axis and revolve in a spiral direction to perform a climbing motion.

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, since the chuck cylinder 2 is provided with a plurality of grooves 5 in the axial direction from the distal end surface 2a thereof in a plurality of rows in the circumferential direction, the rotating tightening cylinder 3 is rotated and the needle roller 4 is By tightening the chuck tube 2 through the chuck tube 2, the groove width d of the split groove 5 is contracted by the pressing force of the needle roller 4, and the inner diameter of the chuck tube 2 is reduced. 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 groove width d of the groove 5, so that the opening diameter at the tip can be strongly reduced, and the gripping force (chuck force) on the tool can be increased.

In the embodiment shown in FIG.
Since there is no change in the thickness of the cylinder except for the part where the groove 5 is provided, it has the advantage of increasing rigidity, but there is a risk that it will be slightly inferior in terms of elastic deformation, so as shown in Figures 4 and 5. A slit 10a opening on the inner peripheral surface of the chuck cylinder and a deep hole 10b continuous with the slit 10a.
A plurality of chuck grooves 10 extending in the axial direction may be arranged in multiple rows in the circumferential direction, and the thickness of the chuck tube 2 may be varied so that the chuck tube 2 is easily elastically deformed. Note that the chuck grooves 10 may be provided continuously and on the same line as the dividing grooves 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, a deep hole may be formed as shown in FIG. 8, or a concave slit groove 10 opening on the outer peripheral surface 2c side of the chuck tube 2 may be formed as an extension of the split groove 5 as shown in FIG. The thickness of the chuck tube 2 can be varied by providing them on a line or alternately in the circumferential direction with the same intersecting angle α, and by these various methods.

(Operations and Effects) According to the present invention, when the groove width of the split groove contracts due to the pressing force of the needle roller, the split groove itself becomes a gap passing through the inside and outside of the cylinder, and the thick part of the chuck cylinder Since the chuck tube is not subjected to any resistance, the contraction effect works well and the inner diameter of the chuck tube can be easily reduced, allowing the tool to be strongly gripped.

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, making heavy cutting tools such as end mills more powerful without vibration. It can be grasped and held. Since there is no notch on the base side from the middle of the chuck tube, sufficient rigidity can be obtained.

Furthermore, the split grooves provided in the axial direction of the chuck tube are 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 it crosses the split groove, the needle roller does not get stuck in the split groove or have difficulty rolling due to the uneven resistance of the split groove, and therefore tightens. The tightening operation of the rotary tube can be performed smoothly and easily.

[Brief explanation of the drawing]

Fig. 1 is a partially vertical front view showing an embodiment of the present invention, Fig. 2 is a 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 the same embodiment. 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 FIG. FIG. 2 is a partially longitudinal front view showing the main parts of the embodiment. DESCRIPTION OF SYMBOLS 1... Chuck body, 2... Chuck tube, 2a... Its tip surface, 3... Rotating tube for tightening, 4... Needle roller, 5... Division groove.

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, the needle rollers spirally revolve at a required helical angle with respect to the outer peripheral surface of the chuck cylinder. Directed axially from the tip surface,
The chuck is provided with a plurality of rows of split grooves extending in the middle of the chuck tube and penetrating inside and outside the chuck tube at a predetermined crossing angle with respect to the needle roller in the circumferential direction.