JP2003266274A - Liquid supply structure for tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an economically advantageous liquid supply structure for a tool capable of securely supplying coolant to a cutter tip even during high speed rotation and increasing a flow rate of coolant by restricting an area of an injection part from a collet and having excellent tool holding performance. <P>SOLUTION: A straight collet 11 in which a cover ring 12 is mounted on a flange 11a is inserted into a holder main body 22. After that, the tool T inserted into the collet 11 tightens the collet 11 and is fixed by a tool holder 21 for use. Coolant C composed of oil mist, cooling liquid, and cooling air flows in from a pull-stud 23 side at a rear end and passes through a slitting groove 11b of the collet 11 as shown by the arrow mark and is injected toward a cutter tip of the tool T through a nozzle hole 12c of the cover ring 12 with force. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool liquid supply structure for injecting a coolant to a tool which is attached to a machine tool spindle.

[0002]

2. Description of the Related Art A straight collet such as a milling chuck that supplies coolant for cooling and lubrication is used for a rotary tool of a machine tool, and is provided at the tip of a cutting tool without an oil hole without a coolant passage inside. May supply coolant. In this case, as shown in FIG. 8, the coolant C is introduced from the gap of the slit groove 3 formed in the conventional straight collet 2 fixed to the holder 1.
Is injected to supply the coolant C in the axial direction along the outer periphery of the attached tool T.

According to this method, the coolant C can be effectively supplied to the cutting edge of the tool T at the time of low speed rotation, but at the high speed rotation of 10,000 revolutions or more, the coolant C is generated by the action of centrifugal force.
Has a drawback that it scatters outward in the radial direction and changes its direction, so that it does not reach the cutting edge of the tool T effectively and lubrication and cooling cannot be performed sufficiently.

The slit dividing groove 3 has a relatively large cross-sectional area, and the total area of the plurality of dividing grooves 3 is large. on the other hand,
The hole diameter of the passage 5 for the coolant C passing through the pull stud 4 is not so large and is usually 6 mm or less.
Since the supply flow rate for passing through the slit 3 cannot be secured, there is a problem that the injection flow velocity cannot be increased. Therefore,
The limit of these conventional techniques is at most about 3000 rpm.

On the other hand, there is an increasing demand for supplying coolant to the tip of the tool T having no oil hole under high speed rotation.
As described above, there is a demand for a straight collet that can reliably supply coolant even at high speeds of 10,000 rpm or more.

[0006] Therefore, the inventors of the present invention, Shokai 64-261
In JP-A-04-04, it has been proposed to provide a nozzle hole 8 in the flange 7 at the front end of the collet 6 as shown in FIG.

[0007]

However, the structure shown in FIG. 9 is excellent in that the flow passage is narrowed to increase the flow velocity, but the slit groove 9 is formed from the rear end, Therefore, the tool holding performance cannot be reliably and firmly held, which affects the tool holding performance.

Further, since the nozzle hole 8 is formed in the collet 6, it is not possible to change the design of the collet 6, and it is necessary to replace the collet 6 when the user changes the specifications, which is not economical.

The object of the present invention is to solve the above problems,
To provide a liquid supply structure for a tool that reliably supplies coolant to a cutting edge even under high-speed rotation and narrows the area of the injection portion from the collet to increase the coolant flow rate and also has sufficient tool holding performance and economy. It is in.

[0010]

To achieve the above object, a straight collet according to the present invention is provided with a flange at the front end of a split collet whose tip is elastically deformable in order to fix a tool. A cover ring is attached in a state where the diameter is reduced, and the cover ring has a nozzle hole for supplying a coolant to the tool tip.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail based on the embodiments shown in FIGS. As shown in FIGS. 1 and 2, the flange 11 is provided on the tip side of the straight collet 11.
a is formed, and slit-shaped slit grooves 11b are formed at a predetermined interval from the flange 11a side toward the rear end. A cover ring 12 is attached to the flange 11 a so as to cover the front thereof, and the enlarged diameter portion 11 c at the tip of the flange 11 a has an inner diameter groove portion 12 of the cover ring 12.
a to the flange 11 by utilizing the elastic deformation of the collet 11.
It is attached in a contracted state.

The cover ring 12 is provided with a tool insertion hole 12b through which a tool is inserted and one or a plurality of nozzle holes 12c for ejecting a coolant in the present embodiment. Further, an O-ring 13 is interposed on the contact surface of the cover ring 12 with the end surface of the tool holder body.
The ring 13 tightly seals between the cover ring 12 and the tool holder body.

Also, the flange 11a and the cover ring 12
A spring member 14 made of, for example, an O-ring is provided between the two, and the spring member 14 maintains the positional relationship between the collet 11 and the cover ring 12 in a state in which both liquid pressures are applied, as described later. The cover ring 12 is prevented from separating from the end surface of the holder body when the collet 11 is mounted on the holder body.

The inner diameter of the tool insertion hole 12b is such that the coolant does not leak out, for example, +0.01 with respect to the outer diameter of the tool.
Some clearance is allowed.

The diameter of the nozzle hole 12c of the cover ring 12 is 1 to 3 mm so that the pressure of the coolant does not decrease, and the angle of the nozzle hole 12c is 3 ° to 15 ° with respect to the axis.
It is oriented toward the central axis. Due to this orientation, the coolant is given inward energy that overcomes the centrifugal force during high-speed rotation.

As shown in FIG. 3, the straight collet 11 having the cover ring 12 mounted on the flange 11a is inserted into the holder body 22. After that, the tool T inserted into the collet 11 as shown in FIG. 4 is used by tightening and fixing the collet 11 by the tool holder 21.

For example, a coolant C consisting of oil mist, cooling liquid, and cooling air flows in from the rear end pull stud 23 side as shown by the arrow, passes through the slot groove 11b of the collet 11, and then the nozzle of the cover ring 12. It is jetted vigorously from the hole 12c toward the cutting edge of the tool T. The pressure of the coolant C normally requires about 3 to 7 MPa,
In the experiment, it was confirmed that the coolant was effectively supplied to the cutting edge of the tool T up to 20,000 rpm.

In this way, the cover ring 12 is provided with the nozzle holes 12c, and if necessary, the number of the nozzle holes 12c and the diameter of the cover ring 12 are exchanged so that the straight collet 11 can be used as it is. The optimum configuration can be selected.

FIG. 5 is an explanatory view of the action of the spring member 14 on the straight collet 11. That is, a gap A for assembly is required between the front end surface of the collet 11 and the inner surface end of the cover ring 12 as shown in the upper half of FIG. Is fixed to the holder body with the holder 21, the coolant C
When supplying the
Will be pushed forward. Therefore, a gap is created between the cover ring 12 and the end surface of the holder 21, the seal of the O-ring 13 does not function, and the coolant C leaks from this gap.

Therefore, the cover ring 12 and the flange 1
When the spring member 14, which is an elastic body, is interposed between 1a to elastically expand the space between them, and the collet 11 is fixed to the holder body 22 as shown in the lower half of FIG. The cover ring 12 and the end surface of the holder 21 are pushed close to each other so that the O-ring 13 operates.

Since the spring member 14 may be provided with an elastic force for expanding the space between the cover ring 12 and the flange 11a, instead of the spring member 14, the leaf springs shown in FIGS. Elastic bodies such as 14a, ring-shaped springs 14b, and corrugated washers 14c may be interposed between the cover ring 12 and the flange 11a as shown in FIGS. 7 (a) to 7 (c).

[0022]

As described above, in the liquid supply structure for a tool according to the present invention, since the cover ring having the nozzle hole is detachably attached to the tip of the straight collet, the coolant can be satisfactorily supplied to the tool. It can be easily replaced and used according to the usage situation.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a state in which a cover ring is attached to a straight collet.

FIG. 2 is a front view of a cover ring.

FIG. 3 is a vertical cross-sectional view of a tool holder body with a straight collet attached.

FIG. 4 is a vertical cross-sectional view showing a state in which a cover ring and a tool are attached to a straight collet.

FIG. 5 is an explanatory view of the action of the spring member.

FIG. 6 is an explanatory diagram of a substitute for a spring member.

FIG. 7 is an explanatory diagram of a usage state of a substitute for the spring member.

FIG. 8 is a vertical cross-sectional view of a conventional tool liquid supply structure.

FIG. 9 is a vertical cross-sectional view of a conventional liquid supply structure for a tool.

[Explanation of symbols]

11 straight collet 11a flange 12 covering 12a inner diameter groove 12b Tool insertion hole 12c nozzle hole 13 O-ring 14 Spring member 21 Tool holder 22 Tool holder body

Claims (4)

[Claims] 1. A flange is provided at a front end of a split collet whose tip is elastically deformable in a radial direction for fixing a tool, and a cover ring is attached in a state where the flange is reduced in diameter, and the cover ring is the tip of the tool. A liquid supply structure for a tool having a nozzle hole for supplying a coolant to the. 2. The liquid supply structure for a tool according to claim 1, wherein the nozzle hole is provided so as to be inclined toward a central axis direction of the cover ring. 3. The liquid supply structure for a tool according to claim 2, wherein an elastic body is provided between the cover ring and the flange to expand the space therebetween. 4. The liquid supply structure for a tool according to claim 1, 2 or 3, wherein the split collet is a straight collet.