JPH0248166Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] This invention relates to an exchangeable head cutting tool.

[Conventional technology]

With the demand for labor-saving and automation of cutting work, there is a need to speed up tool exchange and setup changes including tools.To meet this demand, tools are divided into a cutting head with a cutting edge and a holder. death,
Various head-exchangeable tools have been proposed in which the cutting head can be easily replaced with respect to the holder.

An example of the replaceable tool is shown in FIG. The cutting head 20 is provided with an engagement groove 22 in which the tip of the drawbar 21 is inserted and locked from below, and the drawbar 21 is attached to the holder 23 so as to be slidable in the longitudinal direction. A cutting head 20, which is supported by the receiving part 24, is retracted by a drawbar 21, and is fixed by pressing against the front surface 25 of the holder.
In the above tool, the positioning of the head 20 with respect to the holder 23 is achieved by providing a stepped portion 27 on the holder front surface 25 and the rear end portion 26 of the cutting head 20 that engage with each other.
This is done by engaging 7.

[The problem that the idea attempts to solve]

By the way, in the replaceable tool having the above structure, most of the cutting force in the feed direction during cutting is received by the stepped portion 27, but the tip of the drawbar 21 protrudes from the center of this stepped portion. Therefore, the thickness of the base of the stepped portion 27 becomes smaller as shown in the figure. For this reason, when a large cutting force is applied, the step portion 27 may be deformed and pushed outward to the left and right, causing the cutting head 20 to rise.

Furthermore, in order to attach the head 20 to the receiving part 25 of the holder 23, it is necessary to fit the engagement groove 22 and the tip of the drawbar 21 while engaging the stepped part 27, which is a very time-consuming work. In addition, when attempting to automatically replace the cutting head 20 using a robot hand or the like, the robot hand or the like is required to have extremely high positioning performance, which poses a problem that makes automation difficult.

Furthermore, since the stepped portion 27 faces the rake face side, chips during cutting tend to accumulate on the upper portion of the stepped portion 27, and when the head 20 is removed from the holder 23 at one end, chips may enter the stepped portion 27. This makes continuous attachment and detachment difficult.

On the other hand, as a tool that addresses the above-mentioned drawbacks, there is a tool proposed in Japanese Patent Application Laid-open No. 73206/1983.

This has a vertical wall formed on the lower surface of the cutting head that locks onto the tip end of the holder, and a key block that positions the cutting head on the receiving part that supports the cutting head, allowing the cutting head to be moved onto the key block. The cutting head is pulled into the holder and fixed using a draw bolt installed in the holder. Since the cutting resistance is received by the tip of the holder and both sides of the key block, there is no damage to the retracted part, and the draw bolt is Since the U-shaped opening of the mating head is open to the lower surface, there is an advantage that there is no accuracy error due to intrusion of cutting.

However, in the structure proposed above, the positioning of the cutting head in the feeding direction is
This is done by fitting the key block into the opening, so in order to achieve high repeatability,
It is necessary to minimize the play in the fit between the key block and the U-shaped opening. However, in this case,
High positioning accuracy is required to fit the key block and cutting head, which makes automatic replacement using a robot hand or the like difficult.

Furthermore, since the draw bolt is located above the key block and there is a distance between the receiving part that receives the main component of the cutting force and the retracted position by the draw bolt, an impact force in the direction of the main component of the cutting force is applied to the cutting head. When a large cutting force is applied to the draw bolt, a large moment force will be applied to the retracted position of the draw bolt using the receiving portion as a fulcrum, causing problems such as deformation of the receiving portion and damage to the draw bolt.

This idea was created in view of the above problems, and it is possible to obtain high exchange accuracy without requiring extensive positioning work when fitting the cutting head and holder together, and it is strong enough to withstand heavy cutting. The object of the present invention is to provide a head exchangeable tool having the following functions.

[Means for solving problems]

In order to solve the above problem, this invention provides a forward-tapered protrusion with tapered surfaces on both sides on the front surface of the receiving part of the holder, and the cutting head has a protrusion that is tapered toward the front with tapered surfaces on both sides. A groove is provided which opens to receive the protrusion, and the side surface of the receiving groove is formed into an inclined surface corresponding to the tapered surface, and the cutting head and holder are connected with the side surface of the receiving groove and the tapered surface being pressed together. It is constructed so that the front surface is pressed against it.

[Effect]

Insert the protrusion of the holder into the receiving groove of the cutting head, and in this state, pull in the drawbar inserted into the engagement groove.The tapered surface of the protrusion and the side surface of the receiving groove will press against each other, positioning the head. The end face and the front surface of the holder are pressed together. In this state, the feed component force during cutting is received by the tapered surface of the protrusion, and the main component force is received by the receiving portion.

In the above structure, since the tapered surface of the protrusion and the side surface of the receiving groove are reliably pressed together by the drawing of the drawbar, a relatively large gap can be provided between the tapered surface and the side surface. Therefore, alignment of both does not require high precision.

Moreover, since nothing is interposed between the drawbar and the receiving part, the distance between the receiving part and the retracted position by the drawbar can be reduced, and the moment force applied to the retracted position by the main component force can be reduced.

〔Example〕

Next, an embodiment of this invention will be described based on FIGS. 1 to 4.

As shown in FIG. 1, the holder 1 is provided with a through hole 2 extending through the front and rear surfaces, and a drawbar 3 is slidably inserted into the through hole 2. As shown in FIG. Both end portions of the drawbar 3 protrude from the front and rear surfaces of the holder 1, and a substantially semicircular plate-shaped flange 4 is provided at the tip end thereof.

A threaded portion 5 is formed at the rear end of the drawbar 3, and the threaded portion 5 is screwed into a nut 7 rotatably attached to the rear surface of the holder 1 via a half-split collar 6. As shown in FIG. 2, the drawbar 3 is prevented from rotating at the center by a screw 8, and has a bush 9 and a screw 10 on both sides.
When the nut 7 is rotated, it moves in the axial direction due to the propelling action of the screw, and the amount of protrusion of the flange 4 provided at the tip with respect to the front surface 1a of the holder changes.

A receiving portion 12 is provided on the front surface 1a of the holder 1 at a position below the sliding position of the drawbar 3, and furthermore, on the front surface of the receiving portion 12, both side surfaces are tapered surfaces 13, 13. A tapered projection 14 is formed. Note that the receiving portion 12
The projections 14 may be molded separately from the holder 1 and fixed with bolts or the like.

The cutting head 15 has a throw-away tip 16 attached to its tip, and a tip protruding from the bottom front surface 1a of the drawbar 3 is fitted to its rear end, as shown in FIG. An engagement groove 17 is provided. This engagement groove 7 is open on the upper and lower surfaces, and is inserted into the tip of the drawbar 3 from above. Note that if a cover is provided above the engagement groove 17, it is possible to prevent chips from entering the engagement groove 17.

Further, on the lower surface of the head 15, there is a
A receiving groove 18 is provided into which the protrusion 14 at the tip of the receiving part 12 fits when the receiving part 12 is attached. This receiving groove 18 is open to the lower surface of the head and the engaging groove 17, and its side surfaces 19, 19 are
As shown in the figure, the tapered surfaces 13, 13 of the protrusion 14
It is formed on an inclined surface that closely follows the When the head 15 is retracted by the drawbar 3 and brought into pressure contact with the bolt front surface 1a, the side surfaces 19, 19 are connected to the protrusion 14.
It comes into contact with the tapered surfaces 13, 13 in a face-to-face manner.

This embodiment has the above-mentioned configuration, and the cutting head 15 inserts the tip of the drawbar 3 from below into the engagement groove 17 at the rear end, and inserts the lower surface of the receiving portion 1 into the cutting head 15.
2 and rotate the nut 7 to draw the drawbar 3, so that the rear end surface is brought into contact with the front surface of the bolt 1.
It is fixed by being pressed into contact with a. At this time, the protrusion 14
groove 1 provided in the tapered surface 13 of the head 15 and the lower part of the head 15.
The head 15 is horizontally positioned in a fixed position by abutting the side surface 19 of the head 8 .

When cutting is performed with the head 15 attached as described above, the main component force in the vertical angle direction applied to the chip 16 is received by the receiving part 12, and the component force in the feed direction is absorbed by the tapered surface 13 of the protrusion 14. It can be accepted. That is, since the cutting force is intensively received by the receiving portion 12, which is formed to be strong and strong, the amount of displacement is extremely small, and it is possible to sufficiently cope with heavy cutting and interrupted cutting.

In addition, chips during cutting do not scatter to the engagement part between the protrusion 14 and the groove 18 on the bottom surface of the holder 1, and do not enter the interior of the engagement part, so even if the head 15 is removed and reinstalled. , the same positioning accuracy can be obtained repeatedly by fitting the tapered surfaces together.

Furthermore, in the above configuration, the drawbar 3 is provided along the upper surface of the receiving part 12, and the distance between the receiving part 12 and the retracted position of the head by the drawbar 3 is small, so that a large cutting force in the direction of the principal force is generated. Even when applied to the cutting head 15, almost no moment force acts on the retracted position, and a stable fixed state is maintained.

Further, the tapered surfaces 13, 13 of the protrusion 14 and both side surfaces 19, 19 of the receiving groove 18 are surfaces inclined in the front-rear direction, and are reliably pressed together when the drawbar 3 is retracted. A gap can be provided within the amount of retraction. Therefore, unlike the conventional structure, there is no need to form the U-shaped opening provided in the key block and the head in a highly precise fitted state, and the cutting head 15
The positioning of the receiving portion 12 can be easily performed.

In this embodiment, the drawbar 3 is pulled in by tightening it with the nut 7, but a disc spring, a cam, a wedge mechanism, etc. may be used, and the method is arbitrary.

〔effect〕

This invention has the following effects due to the above configuration.

(i) Since the head is positioned by fitting the protrusion provided on the receiving part of the holder with the receiving groove provided at the bottom of the cutting head, the cutting force is received by the receiving part and the protrusion and is not applied to the retracting part of the drawbar. , stable machining can be performed even in heavy cutting and cutting.

(ii) Protrusions and receiving grooves are provided on the underside of the holder and head, eliminating the possibility of chips getting caught.
No installation errors caused by chips.

(iii) Since the protrusion and the receiving groove can be pressed together by drawing the drawbar, the fitting gap between the two can be increased, and the positioning of the head and the receiving part can be easily performed.

(iv) Since the distance from the receiving part to the retracted position by the drawbar can be reduced, the moment force applied to the retracted position can be kept small;
It can maintain stable strength even during heavy cutting.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view showing an exchangeable head cutting tool adopting this invention, Fig. 2 is a partially cutaway sectional view showing the same tool excluding the rear end of the holder, and Fig. 3 is the tip of the holder. FIG. 4 is a perspective view showing essential parts of the same tool, and FIG. 5 is a plan view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Holder, 3... Drawbar, 4... Flange, 12... Receiving part, 13... Tapered surface, 14...
...Protrusion, 15...Cutting head, 17...
Engagement groove, 18... groove, 19... side surface.

Claims (1)

[Scope of utility model registration request] A cutting head with a cutting blade is provided with an engagement groove into which the drawbar tip is inserted and locked from below, and a holder through which the drawbar is slidably inserted in the front and back direction has a groove that extends forward below the drawbar tip. In an exchangeable head cutting tool in which a protruding receiving part is provided, and the cutting head supported by the receiving part is pulled in with the drawbar and pressed against the front surface of the holder and fixed, the front surface of the receiving part has tapered surfaces on both sides. a protrusion tapered toward the front, and the cutting head is provided with a groove that opens into the lower surface of the cutting head and the engagement groove to receive the protrusion;
The side surface of the receiving groove is formed into an inclined surface corresponding to the tapered surface, and the cutting head and the front surface of the holder are configured to come into pressure contact with the side surface of the receiving groove and the tapered surface. Exchangeable head cutting tool.