JPH0825126A - Throwaway type rotary cutting tool - Google Patents

Abstract

PURPOSE:To use a throwaway type rotary cutting tool, in which a plate-like throwaway tip is put in a slit at the tip of a main body and a series of cutting edges are arranged in the tip, in a wide range from rough working to final finishing work. CONSTITUTION:A slit 2 whose deep end is formed into a V-groove 2a is arranged in the point center part of a main body 1. A contact face 9 of a taper is arranged in the rear part, of a throwaway tip 5 which is inserted into the slit 2 so as to be clamped by a vertical slit part, in the main body point end, and the contact face 9 is pressed and is brought into tight contact with the groove face of the V-groove 2a by means of a lock screw 12 desirably. In this kind of tool, in which an opening of the slit 2 is stopped by means of a bolt 11, relative rotation between the throwaway tip 5 and the main body 1 is easily caused because of a cutting load, however, the relative rotation is hardly caused if the face 9 is fitted in the V-groove 2a, so that torsion at the tip of the main body 1 and reduction in holding stability of the tip 5 are prevented, and consequently, rough machining can be also stably accomplished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a throw-away type ball end mill, a square end mill, a drill, etc. capable of cutting from roughing to high-precision finishing by suppressing twisting due to high load on the tip of the main body. Of the indexable rotary cutting tool.

[0002]

2. Description of the Related Art Conventionally, roughing with a ball end mill,
The finishing process is performed separately using two types of tools.
That is, roughing and semi-finishing are carried out by a throw-away type ball end mill having a split cutting edge as shown in FIG. 4 or FIG. 5, while final finishing is carried out by using the cemented carbide of FIG. It is done with a brazed end mill or a solid carbide end mill.

There are throw-away type ball end mills for finishing. It is shown in FIG. In this ball end mill, a slit 2 of one character that vertically divides from the tip of the main body to the middle in the axial direction is provided at the center of the tip of the main body 1, and a plate-shaped throw-away tip 5 is fitted into the slit 2 and a hole 6 of the tip is formed. The chip 5 is sandwiched by reducing the diameter of the vertically divided portion formed by the slit of the main body with the clamp bolt 11 penetrating through. Further, in the end mill shown in the drawing, the rear end of the slit 2 is formed into a V groove in the thickness direction view of the tip 5, and a V-shaped tip rear portion is fitted therein to improve the positional accuracy of the cutting edge.

[0004]

No conventional ball end mill can perform from roughing to final finishing with one tool, and it is necessary to use at least two tools for each process.

If a single tool is used for the final finishing, the tool cost and the tool replacement time can be reduced, but the end mills with divided cutting edges as shown in FIGS. 4 and 5 have a difficulty in machining accuracy. The end mills shown in FIG. 6 cannot withstand high loads, and none of them can meet the demand.

Therefore, the possibility of roughing was investigated for an end mill of the type shown in FIG. 7 capable of finishing. This end mill markedly reduces the torsional rigidity of the main body due to the installation of slits. Due to the twisting of the tip of the main body, so-called chattering etc. occurs,
The cutting stability that can withstand practical use was not obtained.

Further, in the case of a long peripheral cutting edge, positioning and placement of the chip becomes unstable only by V-fitting the rear end of the chip (displacement of the chip between the clamp bolt 5 and the hole 4 of the chip). (Allowable play) It is difficult to improve the accuracy of the blade runout during setting. Further, in rough machining and semi-finishing, the tip end side of the chip is easily displaced during machining, which adversely affects machining accuracy, tool life, and the like.

Therefore, the first object of the present invention is to reduce the twist of the tip of the main body, which is a drawback of the end mill having the structure shown in FIG. There is.

Further, if necessary, the high positioning accuracy can be maintained by eliminating the problems of chip positioning and poor stability of placement.
The second issue is to extend the tool life.

[0010]

In order to solve the above-mentioned problems, in the present invention, a slit of one character that vertically divides from the tip of the main body to the middle of the axial direction is provided in the center of the main body,
Fit a plate-shaped throw-away tip with a series of cutting blades in the slit, reduce the vertical division of the main body with the clamp bolt attached to the tip side of the main body through the hole of the tip, and use the vertical division to In the rotary cutting tool for sandwiching the throw-away tip as shown in FIG. 7, the rear end of the slit is formed into a wedge groove shape in a side view, and the rear portion of the throw-away tip is fitted into the wedge groove.

It is desirable that the rear part of the throw-away tip is formed into a shape corresponding to the wedge groove and is brought into surface contact with the wedge groove. Further, a lock screw for pushing the throw-away tip obliquely rearward is provided on one side of the vertically divided portion by the slit of the main body, and the rear portion of the tip is pressed against the wedge groove, which also effectively works to suppress twisting of the tip of the main body.

When it is necessary to enhance the stability of the throw-away tip in stationary placement, a key is provided so as to project on the split surface of the main body by the slit, and the key groove provided in the throw-away tip is fitted into this key. .

The pressing of the throw-away tip to the wedge groove by the lock screw is preferably performed by providing a locking groove at the tip of the lock screw on one surface of the throw-away tip in order to reliably transmit the pushing force. , When the indexable insert positioning by key fitting is also used, it is desirable to separately provide the locking groove and the key groove on one surface and the other surface of the chip in order to eliminate the installation restriction in space.

[0014]

[Function] The throw-away tip sandwiched in the slit part
It receives cutting resistance to stop its rotation. On the other hand, the main body receives a driving force and tries to rotate, which causes relative rotation between the throw-away tip and the main body, and a force acts to open a slit at the tip of the main body. In the conventional structure of FIG. 7, only the tightening force of the clamp bolts opposes that force, so the opening of the slit phenomenon occurs in rough machining, the tip of the main body is twisted, and the holding of the chip becomes unstable, causing chattering. Occurs.

On the other hand, in the structure of the present invention, the rear part of the throw-away tip is fitted in the wedge groove part at the rear end of the slit where the rigidity is small, and the fitting part prevents the above-mentioned relative rotation. Therefore, opening of the slit due to this relative rotation and twisting of the tip of the main body are effectively suppressed,
Enables stable cutting without chattering.

The relative rotation restraining force is further increased by stably fixing the rear part of the chip by pressing the rear part of the chip against the groove surface of the wedge groove with a lock screw to improve the adhesion. Further, the lock screw has a great effect of suppressing the movement of the tip in the pulling cutting shown in FIG.

Further, the positioning of the throw-away tip by key fitting minimizes setting error,
Moreover, it is effective in eliminating the chip displacement during cutting by the outer peripheral cutting edge of FIG.

[0018]

FIG. 1 shows an example of the rotary cutting tool of the present invention. This is an example of application to a ball end mill.

In FIG. 1, reference numeral 1 denotes a main body, and a slit 2 of one character is vertically provided at the center of the main body. The extending chip pockets 3 are provided on the outer periphery by changing the position by 180 °. Further, a mounting hole 4 for the clamp bolt 11 is provided near the base of the tip hemisphere so as to traverse the slit 2 and reach one of the vertically split portions to the other.
The rear end portion of the slit 2 is a V-shaped groove 2 in a side view shown in FIG.
It is set to a.

Reference numeral 5 is a plate-like throw-away tip having a semicircular tip side. The throw-away tip 5 to be inserted into the slit 2 has a hole 6 through which the clamp bolt 11 penetrates, a series of cutting blades 7 having an S-shaped blade in a front view, and a lock screw 12 {see FIG. 1 (b)}. A notch 8 for locking the tip, a key groove 10 for fitting a key 13 (see FIGS. 1B and 1C), and a tapered contact surface 9 for closely contacting the V groove 2a are provided.

The key 13 is projected on the split surface of the main body by the slit 2 and attached to one side of the vertical split portion of the main body with a set screw 14. The key 13 is attached in the form of an angular axis in parallel with the axis of the main body, but one key or a plurality of keys may be arranged in a line parallel to the axis of the main body. In order to insert the throw-away tip 5 into the slit 2 from the front end side of the main body and fit the key way 10 into the key 13, the key groove 10 has a state in which one end side is cut out to the rear surface of the tip.

Further, the notch 8 is provided on the surface opposite to the installation surface of the key groove 10, and the tip of a lock screw 12 screwed diagonally rearward to one side of the vertically split portion of the main body is engaged with the notch 8. Stop it.

In the example ball end mill thus constructed, the clamp bolt 11 is removed, the lock screw 12 is loosened to a position where it does not project from the screw hole, and the throw-away tip 5 is inserted into the slit 2 by the key 13 and the key groove 12. Put out and insert. Next, the lock screw 12 is tightened, and the tip 5 is pushed diagonally rearward with the screw so that the contact surface 9 of the taper is V-shaped.
It is brought into close contact with the groove surface of the groove 2a. Then clamp bolt 11
As shown in FIG. 1 (b), the vertical division of the main body is reduced in diameter by this bolt, and the chip is firmly held by one and the other of the vertical division.

According to this structure, the rear part of the throw-away tip 5 is fitted into the V groove 2a and is prevented from rotating, so that the relative rotation of the throw-away tip and the main body due to the cutting load is prevented. Further, since the lock screw 12 blocks the movement of the tip in the pulling-out direction, the pulling cutting shown in FIG. 8 can be stably performed. Further, since the key 13 and the key groove 10 prevent the positional deviation during setting of the chip and the positional deviation due to the lateral pressure during processing, high accuracy and high stability can be maintained even in rough processing.

FIG. 3 shows another embodiment. in this way,
If the tip shape of the main body 1 and the shape of the throw-away tip 5 are changed, the present invention can be effectively used for the square end mill, the drill (not shown) and the like in FIG.

The wedge groove formed at the rear end of the slit 2 may be a semicircular groove 2b shown in FIG. 3 (b). Even with such a shape, if the rear part of the throw-away tip 5 is fitted to the rear part shape so as to correspond to the groove shape, the above-described effect of suppressing relative rotation can be obtained.

[0027]

As described above, the rotary cutting tool of the present invention eliminates the opening of the slit and the twisting of the tip of the main body, which is seen in a tool that holds the throwaway tip of a single plate in the slit at the tip of the main body. Since it is possible to perform stable cutting without chattering even under high load, it is possible to perform from roughing to finishing with one tool, which is extremely advantageous in terms of tool cost and machining setup. Become.

Further, in the case where the chip is key-fitted for positioning and the case where the chip is pressed against the wedge groove with the lock screw, the accuracy of the cutting edge is increased and the displacement of the cutting edge during cutting is prevented. Even if it changes, stability is not impaired and a wide range of processing forms can be supported.

[Brief description of drawings]

FIG. 1A is a plan view showing an example of a tool of the present invention. FIG. 1B is a partially cutaway side view of the essential part of the same tool as above.

2 (a): Plan view of the throw-away tip used in the tool of FIG. 1 (b): Side view of the tip above (c): Front view of the tip above (d) Rear view of the above tip

FIG. 3A is a plan view of another embodiment. FIG. 3B is a partially cutaway side view of the above tool.

FIG. 4 is a plan view showing an example of a conventional ball end mill for rough processing.

FIG. 5 is a plan view showing another example of a conventional roughing ball end mill.

FIG. 6 is a plan view showing an example of a conventional ball end mill for finishing.

FIG. 7A is a plan view of a ball end mill to be improved according to the present invention. FIG. 7B is a side view cross-sectional view of the above end mill.

FIG. 8 is an explanatory diagram of a processing form

FIG. 9 is an explanatory diagram of a processing form

[Explanation of symbols]

 1 Main Body 2 Slit 2a V Groove 2b Semicircular Groove 3 Cutting Pocket 5 Throwaway Tip 6 Hole 7 Cutting Edge 8 Notch 9 Contact Surface 10 Key Groove 11 Clamp Bolt 12 Lock Screw 13 Key

Claims (5)

[Claims] 1. A slit of one character that vertically divides from the tip of the main body to the middle in the axial direction is provided in the center of the main body, and a plate-like throw-away tip having a series of cutting blades is fitted into the slit, and the hole of the tip is inserted. In the rotary cutting tool in which the vertical split portion of the main body is reduced in diameter with the clamp bolt attached to the tip side of the main body and the throw-away tip is sandwiched by the vertical split portion, the rear end of the slit is wedged in side view. A throwaway rotary cutting tool characterized by having a groove shape, and the rear part of the throwaway tip fitted in the wedge groove part. 2. The throw-away rotary cutting tool according to claim 1, wherein a rear part of the throw-away tip is formed into a shape corresponding to the wedge groove and brought into surface contact with the wedge groove. 3. The throw-away type rotary cutting tool according to claim 1, wherein a lock screw for pushing the throw-away tip obliquely rearward is provided on one side of the vertically divided portion by the slit of the main body. 4. The key according to claim 1, wherein a key is provided so as to project on a split surface of the main body by the slit, and an axial key groove into which the key is fitted is provided on the throw-away tip toward the rear surface. Throw-away rotary cutting tool. 5. The lock screw according to claim 3, and the key and the key groove according to claim 4, wherein the throw-away tip has a notch portion for locking the tip of the lock screw on one surface and the other surface on the other surface. The throw-away rotary cutting tool according to claim 1 or 2, which has a structure including the key groove.