JPH04171103A - Boring bar - Google Patents

Abstract

PURPOSE:To improve the accuracy of the regulation of a bored hole diameter in a metallic material boring bar regulatable in the bored hole diameter by dividedly cutting the tip of a bar main body in its axial direction to form a pair of separatedly cut parts so that they may be movable in a separatedly cutting direction and fixable, and attaching cutting tool tips at the mutually opposite positions of the tip of the bar respectively. CONSTITUTION:The tip of a boring bar main body l is formed into a pair of separatedly cut parts 3 by a dividedly cut part 2 passing the axial center of the boring bar. Opposite ends at the tips of the dividedly cut parts are provided with inclined notches 4, to which cutting tool tips 5 are oppositely attached. A dimension regulating mechanism 8 is provided on the way between the separatedly cut parts 3, and a fixing screw 9 on the tip side and a locking screw 10 on its opposite side are mounted with the regulating mechanism 8 put between them. A space between the cutting tool tips 5 is changed through the screw of the regulating mechanism 8 for changing a bored hole diameter D, and the faces of the separatedly cut parts 3 and of the dividedly cut part 2 are fixed through the fixing screw 9 and the locking screw 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a boring bar for cutting holes in metal, and more particularly to a boring bar that allows adjustment of the diameter of the boring.

[Conventional technology]

Conventional boring bars that are attached to milling machines and used for drilling holes include those for precision machining, which have one blade attached to the tip of the boring bar body, and those for rough machining, which have two blades attached to the tip of the bar body. There are two types for processing.

[Problem to be solved by the invention]

By the way, boring bars for precision machining have the problem of low work efficiency, as they are difficult to adjust dimensions because they are flat-sided, so they tend to run out during cutting, and they are not balanced, making it impossible to rotate at high speeds. .

Additionally, boring bars for rough machining have two blades that are well-balanced and can rotate at high speeds, but the dimensions and run-out adjustments are made by moving the two blades individually, making the above adjustments time-consuming. There are problems in that it takes time and accuracy is poor.

As described above, conventional boring bars are mainly single-blade boring bars for precision machining.

SUMMARY OF THE INVENTION Therefore, it is an object of this invention to provide a boring bar in which two blades are attached to the tip of a boring bar body, the dimensions and runout of both blades can be easily and accurately adjusted, and precision milling can be performed using the double blades. is the issue.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the first invention provides a cutting section in the axial direction on the tip side of the boring bar main body to form a pair of cut-off parts, and both cut-off parts A chip attachment part is provided at the opposite end of the cutting tip, and a dimension adjustment mechanism is provided in the middle of the both cutting parts to move both the cutting parts in the surface direction of the cutting part to change the hole diameter between the cutting edges of both the chips. A fixing screw is provided between the distal end of the cut-off portion and the dimension adjustment mechanism to fix the cut-off portions to each other after the size adjustment.

The second invention employs a configuration in which both separated portions of the boring bar main body are twisted at a required angle.

The third invention employs a structure in which a deflection adjustment screw is attached to the rear end portions of both of the cut-off portions, by screwing in the screws to move the cut-off portions toward the distal end side.

[Function] To change the drilling diameter between the cutting edges of the inserts installed at opposing positions at the ends of both cut-off parts, operate the dimension adjustment mechanism with the fixing screw loosened, and move both cut-off parts to the face of the cut. The drilling diameter can be increased by moving the cutting edges of both chimps in the direction apart, and when the drilling diameter reaches the specified diameter, tighten the fixing screw to fix both cut-off parts. become

Further, if center runout occurs in the cut-off portion due to adjustment of the hole diameter, it can be corrected by operating the run-out adjustment screw and moving the tip of the cut-off portion.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 6, a slit 2 passing through the axis is provided along the axial direction on the tip side of a boring bar body 1 formed in the shape of a circular shaft, and a pair of cut-offs are provided on both sides sandwiching this slit 2. It forms part 3.3.

An inclined notch 4.4 is provided at opposite ends of the two separation parts 3.3, and an end of the cut surface facing the above-mentioned notch 4.4 at the tip of both separation parts 3.3. A mounting portion 6.6 for the chip 5.5 is recessed in the mounting portion 6.6, and the chip 5.5 fitted into the mounting portion 6.6 is fixed by screws 7.7.

Chips 5 fixed to opposite ends of both cut-off parts 3.3
and 5, the cutting edges thereof protrude outward from the outer diameter of the boring bar body 1, and the dimension between the cutting edges of both tips 5.5 becomes the poling diameter.

A dimension adjustment mechanism 8 for changing the polling diameter between the cutting edges of the tip is provided in the middle of both separation parts 3.3, and a fixing screw S is installed on the tip side of the adjustment mechanism 8, and a lock screw 10 is installed on the opposite side. ing.

FIG. 4 shows a first example of the dimension adjustment mechanism 8, in which a horizontal hole 11, which overlaps with the cutout 2, is formed on the opposing surfaces of both cutaway portions 3.3.
and an inclined hole 12.12 provided in both separation parts 3.3 so as to intersect with this horizontal hole 11 at the center.
A pair of adjustment members 13 and 13 are inserted into both ends of the force adjustment member 13, and the engagement claws 14 protruding from the outer surface of the force adjustment member 13 are provided on one side in the inclined hole 12 of the separation part 3 and on the other side on the outer surface of the adjustment member 13. The engaging claws 14 are engaged with the inclined holes 12 of the other separating part 3, and the tips of the adjusting screws 16 screwed into the threaded holes 15 of the force adjusting member 13 are brought into contact with the end surface of the other adjusting member 13. It has a similar structure.

In the adjustment mechanism 8 of the first example, when the adjustment screw 16 is screwed in, both the separation parts 3 and 3 are pushed apart in the direction of the surface of the cutout 2 through the adjustment members 13 and 13, and thereby both the chips 5 and 5 are separated. By changing the spacing between the cutting edges, the polling radius will change.

Next, the second example of the dimension adjustment mechanism 8 shown in FIGS.
A horizontal hole 11a that overlaps with the horizontal hole 11a is bored, and a pair of adjustment tubes 13a, 13a are inserted near both ends of the horizontal hole 11a.
An engaging claw 14a protruding from the outer end of the cutaway part 3 on one side, and an engaging claw 14a protruding from the outer end of the adjustment cylinder 13a on the other hand.
a are respectively engaged with the outer surface of the other separation part 3, and both adjustment cylinders 13a and 13a are screwed together with an adjustment screw 16.

As shown in FIG. 8, the adjustment screw 16 has a small pitch male thread 1? The adjusting cylinder 13a has a male thread 17b with a large pitch and a male screw 17b with a large pitch. It is screwed together with b.

Both adjustment cylinders 13a and 138 are screwed together by an adjustment screw 16, and by rotating the adjustment screw 16, both adjustment cylinders 13a and 138 are screwed together.
a and 133 move in the same direction, but male screws 17a and 1? b
The amount of movement changes due to the difference in pitch.

Due to the above movement difference, when the adjustment screw 16 is rotated to either the left or right, both adjustment barrels 13a and 132 move toward or away from each other, and when the adjustment barrels 13a and 13a move apart, the engagement claw 14a,
14a pushes the separation parts 3 and 3 apart in the direction of the surface of the slit 2, thereby changing the distance between the cutting edges of both chimps 5.5 and changing the poling radius.

As shown in FIG. 3, the fixing screw 9 is screwed into a stepped elongated hole 18 provided in one of the separated sections 3 and into a threaded hole 19 provided in the other separated section 3, and is tightened to separate both separated sections 3. Cut and 3 and fasten so that the sides of 2 overlap.

As shown in FIG. 5, the lock screw 10 is screwed into a long hole 20 provided in one cut-off part 3 and into a threaded hole 21 provided in the other cut-off part 3 so as to be inclined at 45 degrees with respect to the cut 2. , the two separated portions 3 are fastened so as not to move in the plane direction of the cut 2.

As shown in FIG.
Screw holes 23, 23 are provided at right angles to the slit 2, and a runout adjusting screw 24 is screwed into either one of the screw holes 23 or 23.

A circular shaft 25 is embedded in the boring bar body 1 in a penetrating manner along the surface direction of the cut 2 and partially intersecting both screw holes 23 and 23, and a run-out adjustment screw screwed into the screw hole 23 or 23 is embedded in the boring bar body 1. The tip of 24 comes into contact with this circular shaft 25.

When the run-out adjustment screw 24 is tightened in contact with the circular shaft 25, the root portion of the cut-off portion 3 or 3 escapes from the circular shaft 25, thereby causing the tip side of the cut-off portion 3 or 3 to move in the opposite direction. This will correct the center run-out of the cut-off portion 3.3 that has occurred with respect to the boring bar 1.

In the boring bar 1, both separation parts 3.3 are given a 90° twist to improve the mobility in the direction of adjusting the diameter of the poling, to facilitate the operation of the dimension adjustment screw 15, and to make it easier to operate the dimension adjustment screw 15 in the direction of rotation during cutting. On the other hand, since the torsion direction is free to escape, the repulsion mass is small, which reduces the occurrence of vibration.

The boring bar of this invention has the above configuration,
Readjustment members 13 and 13 of the dimension adjustment mechanism 8 shown in FIG.
In a natural state in which the tips 5.5 are brought close to each other and no pushing-opening force is applied to the cut-off portions 3.3, the poling diameter between the cutting edges of the tips 5.5 is the minimum diameter.

In this state, by tightening the fixing screw 9 and the locking screw 10 to fasten both the separation parts 3.3, polling with the minimum diameter can be performed.

Next, in order to increase the polling diameter, with the fixing screw 9 and locking screw 10 loosened, the adjusting screw 16 is rotated in the direction in which the readjusting members 13 and 13 are separated.

When the readjustment member 13.13 moves in the direction of separation, the engagement claw 14.14 of the readjustment member 13.13 engages the separation portion 3.3.
is pushed open along both directions of the slit 2, and the distance between the cutting edges of the tips 5 attached to the tips of each becomes wider.

Measure the distance between the cutting edges of both tips 5.5 with a micrometer,
When the predetermined poling diameter is reached, the fixing screw S and the locking screw 10 are tightened, and both the separation portions 3.3 are fastened together, thereby making it possible to perform poling with the set diameter.

In addition, after setting the polling diameter, if center runout occurs in the cutaway part 3.3 in the rotating state, the runout can be adjusted using the threaded hole 23 provided at the base of the cutoff part that is in a positional relationship on the opposite side to the runout direction. Screw in the screw 24, bring its tapered tip into contact with the circular shaft 25, and tighten.

As a result, the distal ends of the separation parts 3 and 3 move to the side opposite to the runout, and the runout that has occurred is corrected.

[Effects] As described above, according to the present invention, chips are attached to opposite ends of the cut-out portion formed by cutting, and both cut-off portions are moved in the direction of the surface of the cut using the dimension adjustment mechanism. Therefore, the hole diameter can be adjusted by moving both tips at the same time, and the hole diameter can be easily adjusted and changed with high precision, making it possible to respond to a wide range of changes in the poling diameter.

In addition, since the insert is attached on both sides, it is possible to perform highly parallel cutting with no run-off, and it is also possible to measure the hole diameter and run-out of the cutting, and because it is balanced, high-speed rotation is possible and high roundness is achieved. Polling can be performed and precision milling can double the feed rate to improve efficiency.

Furthermore, since the boring bar main body is integral, it is rigid, and the mating tip opens and closes evenly, allowing for highly accurate adjustment and reliably correcting the occurrence of center runout.

[Brief explanation of drawings]

FIG. 1 is a front view showing a first embodiment of the boring bar according to the present invention, FIG. 2 is a side view of the same, FIG. 3 is an enlarged cross-sectional view taken along arrows ■-■ in FIG. The figure is the arrow in Figure 1■
- An enlarged sectional view along ■■, Figure 5 is the arrow IV-I in Figure 1.
FIG. 6 is an enlarged sectional view taken along arrow V-■ in FIG. figure,
FIG. 8 is a cross-sectional view of the same as above. 1...Boring bar body, 2...Cut, 3...Separation part, 5...Chip, -8...Dimension adjustment mechanism , 9... Fixing screw, 10...
...Lock, 11...Horizontal hole,
13...adjustment member, 16...adjustment, 24...runout adjustment.

Claims (3)

[Claims] (1) A cut is provided in the axial direction on the tip side of the boring bar body to form a pair of cut-off parts, a chip attachment part is provided at the opposite end of the cut-off parts of both cut-off parts, and a chip attachment part is provided in the middle of both the cut-off parts. , a dimension adjustment mechanism is provided for moving both cut-off parts in the plane direction of the slit to change the hole diameter between both chip cutting edges, and between the tip of the cut-off part and the dimension adjustment mechanism, both cut-off parts are moved in the direction of the surface of the cut. A boring bar with fixing screws that fix the two together. (2) In the boring bar according to claim (1),
A boring bar with a required angle of twist on both separated parts of the boring bar body. (3) The boring bar according to any one of claims (1) and (2), in which a run-out adjustment screw is attached to the rear end portion of both the cut-off parts to provide movement toward the tip side of the cut-off part by screwing. .