JPS63306848A - Holder for round shank cutters - Google Patents

Abstract

PURPOSE:To attach a round shank portion to a holder stably, surely, firmly and simply by making a construction in such a manner that a round shank portion touches and presses insertion hole wall surfaces of the two sides for forming a two-side included angle in a pillar-shape insertion hole and the point of a fastening bolt within the insertion hole. CONSTITUTION:When the shank portion 4a of a round shank cutter 4 or the like formed in combination with cutters such as a drill, a reamer etc., on the tip of a round pillar-shaped shank portion 4a is inserted and fastened into the pillar-shape insertion hole 2a of a holder 1, the shank portion 4a touches the linear contact portions thereof with the insertion hole wall surfaces of two sides for forming a two-side acute angle and the point of a fastening bolt 5 screwed in a screw hole 2b formed on a holder wall portion on the bisector D of the included angle C to be pressed and fastened and the round shank portion 4a is attached to the holder 1 in a good stable condition.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a holder for round shank cutters that can be easily and reliably attached to the holder while maintaining high run-out accuracy of 1 degree. be.

(Conventional technology) Conventionally, cutters for hole cutting cut in a narrow space, so there were no protrusions on the blade that would obstruct the flow of chips, and the shank had a round cross-section with few irregularities. Cutters are used.

Mounting jig (e.g. holder) for drilling holes like this
For this purpose, screw-on type, pin lock type, etc. indexable holders are used, and the material thereof is made of cemented carbide or the like.

To secure cutters to the holder, the sleeve is moved via a drawper, and the collet is tightened and fixed to the tool rest by opening the collet.The collet method is used to fix the cutters to the holder. , a fastening method in which a bridge-shaped presser metal fitting such as a wedge-on type or clamp-on type is placed on this insertion hole by pressing it with a bolt from the right angle direction, and this is screwed and tightened with a bolt, A fixed method is used.

(Problems to be Solved by the Invention) However, with the various fastening and fixing methods described above, it is difficult to mount a round shank cutter to a holder reliably, easily, and with high runout accuracy.

In addition, methods of pressing and fixing cutters to the holder using bridge-shaped metal fittings such as wedges and clamps
The pressing and screwing operations of the bolts are complicated, and it is not possible to fix them easily, reliably, and firmly.

(Means for solving the problems) As a result of various studies to solve the above-mentioned problems, the inventor of the present invention found that
We have developed a holder for round shank cutters that allows round shank cutters to be mounted securely, firmly, and with high run-out accuracy, and that can be easily inserted and removed.

That is, the present invention provides a holder for round shank cutters having a hole for inserting and supporting a round shank cutter, which is provided with a columnar hole having a cross section in which at least one two sides include an angle. , and the insertion hole is dimensioned and shaped so that when the round shank cutter is inserted, the outer circumference of the round shank cutter comes into line contact with the wall surfaces of the insertion hole on two sides forming the included angle. , a plurality of wire holes are provided in the boulder wall on the bisector of the included angle,
A round shank cutter type fastening bolt is screwed into the wire hole, and when the round shank cutter type is placed in the columnar insertion hole, the wire contact portion with the wall surface of two sides of the included angle and the tip of the tightening bolt are connected. This is a holder for round shank cutters, which is characterized by being stably supported by abutting and pressing.

In the present invention, the round shank portion of the round shank cutter is arranged in a cross section where an included angle exists on at least one two sides of a columnar fitting hole drilled in a mounting jig holder. It is brought into line contact with the wall surface of the insertion hole, and pressed into contact with the tip of the fastening bolt placed on the bisector of the included angle, that is, as shown in FIG. The structure is such that the round shank is in contact with the holder in a well-balanced manner at three points, and as a result, the round shank part is stably and firmly attached to the holder, ensuring high run-out accuracy, and can be easily attached.

The holder is usually cylindrical and made of a high-strength material to be attached to a drilling machine, milling machine, etc., but is not limited to this, and may be, for example, rectangular or block-shaped. good.

In round shank cutters, the outer periphery of the shank generally has a circular shape, but a portion of the circumferential surface of the shank may be made flat by cutting.

The term "round shank cutter" as used in the present invention refers to one in which the shank part is cylindrical and various types of cutters such as drills, reamers, end mills, bits, grindstones, etc. are connected to the end of the shank.

As described above, in the present invention, when the outer peripheral part of the round shank is inserted into the insertion hole and tightened, the round shank part contacts and presses the two line contact parts on the side wall of the insertion hole and the tip of the tightening bolt. The support provided by these points has a good mechanical balance, provides stable support, and allows round shank cutters of any outside diameter to be easily attached to the holder.

As a result, the occurrence of chatter (vibration phenomenon) during cutting operations due to poor pressure contact between the round shank cutter and the holder, as in conventional technology, is eliminated, maintaining a high machining f# degree, extending the life of the cutting tool, and preserving the accuracy of the machine. , safety etc. can be improved, so the present invention is particularly suitable for automation of NC lathes, etc.
It will be extremely useful as a part of labor-saving machinery.

(Example) An example of the holder for round shank cutters of the present invention will be specifically described below based on the drawings.

Figure 1 is a perspective view of a holder for round shank cutters according to an embodiment of the present invention, Figure 2 (1) is a sectional view taken along line 1-1 in Figure 1, and Figure 2 (2) is a shank section. 3 (1) to (6) are cross-sectional views taken along the same line 1-1 showing an embodiment in which a round shank cutter with a part of the circumferential surface cut flat is installed.
FIG. 3 is a diagram showing the cross-sectional shapes of various fitting holes of the holder for round shank cutters and the supporting state of the round shank portion.

In the oral example shown in Fig. 1, the holder 1 for round shank cutters has a flange portion of a cylindrical support 3 made of alloy steel or the like and a 7-run portion of the holder main body 2 that are connected to a flat head bolt with a hexagonal socket. 6 screwed together. Further, as shown in Fig. 2, a fitting hole 2a is bored in the cylindrical portion, and the hole 2a is approximately square in cross section (cut to a size that allows the round shank portion of a round shank cutter to be fully inserted into the hole 2a).
However, the corners are warped).

As shown in FIGS. 2 and 3 (1), the dimensions and shape of this insertion hole 2& are such that the outer periphery 4a of the shank of the round shank cutter 4 can be inserted therein without interference, and the outer periphery thereof First, the outer circumferential surface of the round shank portion is brought into line contact with the two sides of the two sides of the included angle wall of the insertion hole 2a at two places (see Fig. 3 (1)). A,
B) The minimum inner diameter of the insertion hole 2a is configured to be slightly larger than the diameter of the round shank portion so that the insertion hole 2a is evenly and closely supported.

Further, the holder main body 2 is pressed with the round shank portion,
For fastening, a wire hole 2b is provided on the negative side of the wall of the push-in insertion hole, into which a fastening bolt (hexagon socket head bolt) 5 is screwed.

Furthermore, the cross-sectional shape of the insertion hole 2a is such that the shank outer peripheral portion 4a is in line contact with two locations on the insertion hole wall surfaces A and B with an included angle C on two sides, for example, as shown in FIGS. 6)
As shown in Figure 3 (2), the triangle (Figure 3 (2)), quadrilateral (
(4) in FIG. 3), a hexagon ((6) in FIG. 3), or a partially deformed polygon ((1), (3), (5) in FIG. 3).

As shown in FIG. 3(1), the walls A and B of the insertion hole 2a have a V-shaped cross section 1, and form an included angle C formed by these wall surfaces A-B. A wire hole 2b is screwed into the wall surface of the insertion hole 2a on the bisector of the included angle C. In principle, the shape of the insertion hole may be an ellipse, a parabola, a collection of circular arcs, etc., but this is difficult to manufacture.

In the examples shown in FIGS. 1 and 2, the insertion hole 2a is made into a square shape,
Moreover, the corner of the apex is rounded to ensure the wall thickness of the insertion part.

As shown in Fig. 2 (2), a part of the outer periphery 4a of the shank of the round shank cutter 4 is machined flat (this is often the case, in which case the tightening bolt Since the contact is between the tip and the flat part, the contact area is large, so the round shank part can be more stably attached to the holder.

Therefore, if a round shank cutter 4 made of cemented carbide is inserted into the holder body 2 of the round shank cutter holder 1 and the bolt 5 is screwed in using a hexagon spanner,
The round shank cutters 4 can be securely and firmly fastened to the holder 1.

As for the material of the members, ordinary metal materials can be used except for the wall surface of the insertion hole and the fastening bolt, which require high strength and high hardness.

Next, talking about the runout accuracy in the holder of round shank cutters, the best runout accuracy of the round shank when using a collet chuck is about 10 μ-, but when using the present invention, the runout accuracy is always 1-2
It is possible to ensure high accuracy comparable to μ theory. That is,
In the present invention, the wall surfaces A and B of the two contact portions in the insertion hole 2a of the round shank are flat, but in general, flattening processing can easily achieve high smoothness accuracy. The contact surface between the smooth plane and the shank outer circumferential portion 4a is extremely uniformly and tightly adhered to ensure line contact. As a result, the round shank cutters can be securely and securely fastened in the boulder insertion hole 2a with high precision.

Furthermore, the cutters can be easily attached, detached, and replaced by only rotating a small number of bolts 3.

(Effects of the Invention) As described above in detail in the examples and the like, the holder for round shank cutters of the present invention has a cross section in which at least one two-side included angle of the columnar insertion hole exists, and two sides forming the included angle. A structure in which contact is made with the line contact portion with the wall surface of the insertion hole, and the tip of the fastening bolt placed on the bisector of the included angle is contacted and pressed, that is, contact is made at three points when expressed in cross section. As a result, the outer circumference of the round shank can be stably, reliably, firmly and easily attached to the holder.

In addition, even if the diameter of the round shank is different, the line contact position of the outer periphery of the shank with the wall surface of the insertion hole is only slightly shifted.
Since there is always uniform line contact, it is possible to secure highly accurate, reliable, and strong fastening of round shank cutters of various diameters.

Furthermore, the holder for round shank cutters of the present invention has a simple structure, and the number of component parts is very small, consisting of only a screw and a holder body, so it is easy to manufacture and low cost. It becomes low and ugly.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a holder for round shank cutters according to an embodiment of the present invention, Fig. 2 (1) is a sectional view taken along line A-A in Fig. 1, and Fig. 2 (2) is a shank portion. A sectional view taken along the I-1 line showing an embodiment of mounting a round shank cutter with a part of the circumferential surface cut into a flat plate shape, Fig. 3<1) to (6)
FIG. 2 is an explanatory diagram of the cross-sectional shapes of various fitting holes of the holder for round shank cutters and the support state of the round shank part. 1: Holder for round shank cutters, 2: Holder body, 2a: Fitting hole, 2b: Wire hole, 3: Support, 4: Round shank cutter, 4 &: Outer periphery of shank, 5: Tightening bolt.

Claims (1)

[Claims] (1) In a holder for round shank cutters having a insertion hole for inserting and supporting a round shank cutter, a columnar insertion hole having a cross section with at least one included angle on two sides is bored, and The insertion hole has a size and shape such that when the round shank is inserted, the outer circumference of the round shank comes into line contact with the wall surfaces of the insertion hole on two sides forming the included angle, and the fitting hole has a size and shape that are such that when the round shank is inserted, the outer circumference of the round shank makes line contact with the wall surfaces of the insertion hole on two sides forming the included angle. A plurality of screw holes are provided in the wall of the holder on the dividing line, and a round shank cutting tool fastening bolt is screwed into the screw hole. A holder for round shank cutters, characterized in that the line contact portion with the wall surface of the cutter is brought into contact with and pressed by the tip of the fastening bolt to stably support the cutter.