JPH0217281B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention grips the shank of a cutting tool, etc. and is attached to a spindle of a milling machine, machining center, etc., and actively transmits the power transmitted to the spindle to the tool. Regarding the check to be made.

(Prior Art) The chuck according to the present invention generally has a structure as shown in FIG. The chuck tube contracts as it rotates. For example, in the device disclosed in Utility Model Publication No. 41-2987, a tapered outer circumferential surface of a tapered chuck tube is formed at the tip of the main body, and a retainer formed in a tapered shape corresponding to the tapered outer circumferential surface is attached to A pocket is formed which is inclined at the same fixed angle, a plurality of needle rollers are held in this pocket, and a rotary cylinder is engaged with the needle roller. Therefore, when the rotary tube is rotated, the needle roller rotates in a direction perpendicular to the axis of the needle roller and revolves around the chuck, causing the rotary tube to contract the chuck tube via the needle roller and grip the tool shank. It's getting old.

(Problems to be Solved by the Invention) However, as mentioned above, in this type of chuck, all the needle rollers are normally held uniformly at an angle of about 2 degrees with respect to the axis by a retainer. In other words, the needle roller rests on the tapered outer circumferential surface of the chuck tube with a uniform inclination. As a result, a force is generated in the direction of the arrow b in which the needle roller rolls on the tapered outer circumferential surface of the chuck tube and tends to fall, as shown in FIG. In order to tighten the tool shank, a wrench is applied to the rotating barrel and the rotating barrel is rotated to tighten the chuck barrel, but when the spanner is removed from the rotating barrel, the force b that causes the tool to roll and fall is generated. , the rotating cylinder tends to rotate naturally in the direction of loosening. For this reason, it is necessary to use a wrench to tighten the rotating tube while stopping the rotation by hand, resulting in extremely poor operability. In addition, as mentioned above, with the needle roller configuration, the rotary tube can easily rotate and tighten the chuck tube even with a weak force, but on the other hand, it can be easily loosened even with a weak force, so it can be used by attaching it to the spindle of a machine (not shown). There is a risk that the rotating cylinder will become loose due to machine vibration or cutting vibration, and the tool will fall off due to the constant loosening force.

Furthermore, in order to solve this problem, there were some models in which an elastic member made of urethane rubber was interposed between the collar and the rotating tube (see Utility Model Application Publication No. 57-38708, etc.), but the chuck itself The need for a separate elastic member increased the chuck's size and cost. Furthermore, there was a possibility of center runout, so high-precision machining was required.

(Means for solving the problem) The present invention provides a chuck tube 5 having a tapered outer peripheral surface provided at the tip of the chuck body,
A truncated conical retainer 1 built into the outer peripheral surface of a chuck cylinder, and multiple rows of needle rollers 3 inserted into the retainer at a predetermined angle of inclination to the axis.
and a rotary tube 8 fitted into the chuck tube and having an inner diameter surface with the same taper as that of the chuck tube, in which a small number of needle rollers having an inclination angle different from that of the majority of needle rollers are used. A chuck characterized by comprising:
The rotary tube can be tightened optimally according to the weight of the rotary tube and the rotation of the chuck.

(Function) When the rotary tube is rotated to attach a cutting tool to the chuck, most of the needle rollers with the same inclination rotate in a direction perpendicular to the axis of the needle rollers and revolve around the axis spirally. The different needle rollers also attempt to revolve helically while rotating in a direction perpendicular to the axis of the needle roller. However, a small number of needle rollers with different inclination angles are pulled in the direction in which the majority of needle rollers with the same inclination angle rotate and revolve helically, and a small number of needle rollers with different inclination angles slide differentially. While doing so, it moves in the same direction as the majority of needle rollers. This differential sliding spiral revolution acts as a stopper and completely prevents the rotating cylinder from loosening. Therefore, the rotary tube can be sufficiently tightened without having to press the rotary tube by hand.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a chuck according to the present invention, which is conventional except for the angle of inclination of the needle roller.
That is, the chuck main body A has a shank 11 at one end that is attached to a spindle of a machine tool, and a chuck tube 5 having a tapered shape at the other end. In addition, there are multiple long holes 1 on the circumference of the chuck tube.
2, and a tool attachment hole 13 is bored in the center.
The truncated conical retainer 1 has the same taper shape as the chuck tube 5 and is fitted into the chuck tube. A large number of needle rollers 3 and 4 are installed at a predetermined angle of inclination with respect to the axis as will be described later. It is arranged on the outer peripheral surface of the chuck tube. Furthermore, a rotary tube 8 whose inner peripheral surface has the same taper as the chuck tube is fitted in a state in which it is in contact with the needle roller, and the cutting tool is mounted in the tool attachment hole 13 of the chuck tube by rotating the rotary tube. (not shown) is tightened and fixed via a needle roller. In addition, 6, 6 is a dustproof seal provided on the facing surface of the chuck tube 5 and the rotating tube 8, 7 is a stopper ring fitted to the tip of the chuck tube 5, and 9 is provided on the rear inner end surface of the rotating tube 8. It is a stop that was given.

FIG. 1 shows an embodiment of the retainer used in the chuck of the present invention, in which the needle rollers 3 in the first, second and fourth rows have an inclination angle αa with respect to the Y-Y axis of the retainer 1. The needle rollers 4 in the third row are all fitted into the pocket 2 with an inclination angle αb that is gentler than the inclination angle αa, and the inclination angles are different. In addition to this embodiment, the inclination angles of multiple rows of needle rollers in the axial direction may be changed, or the inclination angles of only some needle rollers in rows or columns may be made different from the inclination angles of many other needle rollers. Good too. A retainer 1 incorporating a needle roller 3 shown in FIG. A stop ring 7 is inserted to prevent the retainer 1 from coming off. Next, the rotary cylinder 8 is inserted onto the retainer and engaged with the needle rollers 3 and 4, and the stop ring 9 prevents the rotary cylinder from falling off.

In this case, the needle rollers in the 1st, 2nd, and 4th rows rotate and revolve helically, while the needle rollers in the 3rd row helically revolve while sliding differentially, but because they are tightened by the rotating cylinder, The differentially sliding needle rollers in the third row function as a stopper and can completely tighten the chuck tube 5.

To explain the operating principle of the present invention with reference to FIG. 2, a pocket 2 is formed on the tapered surface of a tapered truncated conical retainer 1 and is inclined to the left from the Y-Y axis, and a needle roller 3 is inserted and the retainer is rotated to the right. The needle roller 3 revolves around the outer periphery of the chuck tube while rotating in the direction of arrow a. On the other hand, the needle roller 31 tries to rotate in the direction a', but when there are many needle rollers 3, it is pulled by the many needle rollers 3 and moves in the direction a'' by differential sliding. 3 rolls in the direction b and becomes loose, and the needle roller 31 has a
The force acting to move in the direction b' can completely prevent the needle roller 3 from rolling and loosening. The comparison between needle rollers 3 and 31 is an extreme example, but the inclination angle of the needle rollers is α ₁ for needle roller 32, α ₂ for needle roller 33,
α ₃ in the needle roller 34 (however, α ₂ > α ₁ > α ₃ )
Any combination of inclination angles can be made as shown in FIG.

(Effects) As described above, the present invention is equipped with a needle roller having an inclination angle different from that of the majority of needle rollers, so even if machine vibrations or cutting vibrations occur, the rotary cylinder will not loosen, allowing processing. The tools inside never fall out, so you can continue machining. Furthermore, even when using a spanner, the rotating tube can be sufficiently tightened without having to hold the rotating tube by hand each time the spanner is removed from the spanner hook 10, which is extremely advantageous in terms of operation.

In addition, by changing the inclination angle of any one of the plurality of needle roller rows fitted in the retainer, or by changing the inclination angle of one or more of the many needle rollers, the rotation Since the moving tube is prevented from loosening and is completely tightened, there is no possibility that the rotating tube will loosen due to vibrations during cutting or vibrations of the machine, and cutting can be performed with peace of mind without the risk of accidents. can.

[Brief explanation of drawings]

Figure 1 is a partial view of a retainer and needle roller according to an embodiment of the present invention, Figure 2 is an explanatory diagram of the principle of the invention, and Figure 3 is a front view of a chuck incorporating the retainer of the present invention. be. 1...Retainer, 3...Needle roller, 5...Chuck tube, 8...Rotating tube.

Claims (1)

[Scope of Claims] 1. A chuck tube 5 having a tapered outer circumferential surface provided at the tip of the chuck body, one truncated conical retainer 1 incorporated in the outer circumferential surface of the chuck tube, and On the other hand, it consists of multiple rows of needle rollers 3 inserted into a retainer with a predetermined inclination angle, and a rotating cylinder 8 fitted into the chuck cylinder and having an inner diameter surface with the same taper as the chuck cylinder. 1. A chuck comprising a small number of needle rollers having an inclination angle different from the inclination angle of the majority of the needle rollers. 2. The chuck according to claim 1, wherein the number of needle rollers having different inclination angles is one or more. 3. The chuck according to claim 1, wherein the needle rollers having different inclination angles are all needle rollers belonging to a predetermined row.