JP2002103108A - Line boring bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a line boring bar capable of obtaining high boring accuracy without impairing the rigidity and the dynamic balance of a tool body 1 even when a recess 13 must be formed on an outer circumference of the tool body 1. SOLUTION: In the line boring bar in which the recess 13 is formed on the outer circumference of the substantially columnar tool body 1, and a cutting blade member 9 having a cutting blade 2B protruded from the outer circumference of the tool body 1 is fitted to the recess 13 so that the projection of the cutting blade 2B is adjustable, a bridging part 21 for connecting wall surfaces 13C and 13C of the recess 13 is provided on an opening part of the recess 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line boring bar for finishing a prepared hole formed in a workpiece to a predetermined inner diameter.

[0002]

2. Description of the Related Art A line boring bar as shown in FIGS. 4 to 8 is used to finish a pilot hole formed so as to penetrate such a workpiece to a predetermined inner diameter. In the line boring bar shown in these figures, the tool body 1
Are provided side by side in the longitudinal direction of the tool main body 1 so as to protrude from the outer periphery of the tool main body 1. The protruding amount of these cutting blades 2 to the outer peripheral side of the tool main body 1 is adjustable. hand,
By inserting such a tool main body 1 into the pilot hole and supporting the front end thereof with the bearing 3, and attaching the rear end portion 4 to a machine tool and rotating the tool main body 1 to feed the tool main body 1 in the longitudinal direction, The pilot hole is finished to a predetermined inner diameter by the cutting blades 2.

Here, when adjusting the amount of protrusion of the cutting blade 2, for example, as shown in FIGS.
A mounting hole 5 is pierced in the diametric direction of the tool body 1, and a cutting tool member 6 having a cutting edge 2 </ b> A formed at a tip is inserted into the mounting hole 5, and a rear end side of the cutting blade member 6 is inserted. The protrusion amount of the cutting blade 2A is adjusted by an adjusting screw 7 screwed into the mounting hole 5 from the tool main body 1 in a direction orthogonal to the mounting hole 5.
There is a method of fixing the cutting blade member 6 with a clamp screw 8 screwed into the cutting blade member 6. However, according to such a method, it is easy to attach the cutting blade member 6 to the tool body 1, but it is difficult to more accurately adjust the amount of protrusion of the cutting blade 2 </ b> A. Used for roughing before finishing to the inner diameter of In order to finish the prepared hole formed by the cutting blade 2A of the cutting blade member 6 to a predetermined inner diameter, a fine-adjustable cutting tool as shown in FIGS. 4 and 6 to 8 is used. Used as the member 9.

This fine-adjustment type cutting tool is, for example,
No. 41523, Japanese Utility Model Publication No. 2-3365, etc., and a main body 10 buried in the tool main body 1 and protruded from the main body 10 to the outer peripheral side of the tool main body 1 so as to have a tip. A head 11 provided with a cutting blade 2B, an adjustment nut 12 interposed between the head 11 and the main body 10 to finely adjust the amount of protrusion of the head 11, that is, the amount of protrusion of the cutting blade 2B; The adjustment nut 12 and the head 11
A screw mechanism, a spring mechanism, a detent mechanism, and the like (not shown) are housed and interposed in the main body 10, and a cutting tool such as a spanner is hooked on the adjustment nut 12 and turned to form a cutting blade. With the direction of 2B kept constant, the head 11 can be made to protrude and retract very accurately according to the amount of rotation of the adjustment nut 12. Accordingly, by finishing the prepared hole roughly processed by the cutting blade member 6 with the cutting blade member 9, more accurate finishing of the prepared hole formed in the workpiece can be performed.

[0005]

When such a fine-adjustment type cutting tool is used as the cutting blade member 9, the head 11 on which the cutting blade 2B of the cutting blade member 9 is provided has a certain degree. Due to the size, the recess 13 for accommodating this
Must be formed on the outer periphery of the tool body 1. However, as described above, the cutting blade member 9 has the head 11
And the main body 10, that is, by rotating an adjusting nut 12 interposed at the neck of the cutting blade member 9 with a working tool such as a spanner, to adjust the protrusion amount of the cutting blade 2 </ b> B. In order to secure the space for rotating the work tool by inserting it into the recess 13 and hooking it on the adjustment nut 12, the bottom surface 13 </ b> A of the recess 13 around the adjustment nut 12 remains flat and the outer peripheral surface of the tool body 1. 1
A must be formed to intersect A. Accordingly, in a line boring bar using such a cutting blade member 9, the outer periphery of the tool body 1 is largely cut off by the recess 13 at the position where the above-mentioned recess 13 is formed, that is, at the position where this cutting blade member 9 is attached. Inevitably, the rigidity of the tool main body 1 is impaired, and the tool main body 1 may bend or bend during the processing, leading to deterioration of the processing accuracy.

Moreover, when the outer periphery of the tool body 1 is largely cut off by the recess 13 in this manner, the center of gravity of the tool body 1 at the position where the recess 13 is formed is located in a cross section orthogonal to the longitudinal direction of the tool body 1. Since the tool body 1 is shifted to the opposite side to the recess 13, the dynamic balance during rotation of the tool body 1 during machining deteriorates, the tool body 1 oscillates, and the machining accuracy may be further deteriorated. However, in order to prevent such deterioration of the dynamic balance, the outer periphery of the tool body 1 on the opposite side to the recess 13 in the circumferential direction may be cut out in the same manner as the recess 13 to form the notch 14 as shown in the figure. However, if the notch 14 is formed in the tool body 1 on the opposite side of the recess 13 to reduce the thickness of the tool body 1,
The rigidity of the tool main body 1 at the position where the cutting blade member 9 is attached is further impaired, and the bending and bending of the tool main body 1 are more likely to occur due to the cutting load acting on the cutting blade 2B during machining. With a line boring bar having such a configuration, it has been difficult to achieve both maintaining the dynamic balance and ensuring the rigidity of the tool body 1.

The present invention has been made in view of such circumstances, and as described above, a tool body such as a line boring bar having a fine-adjustment type cutting tool having an adjustment nut on a neck as a cutting blade member. It is an object of the present invention to provide a line boring bar capable of obtaining high machining accuracy without impairing the rigidity and dynamic balance of the tool body even when a concave portion must be formed on the outer periphery of the bar.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve such an object, the present invention provides a method in which a recess is formed in the outer periphery of a substantially cylindrical shaft-shaped tool body, and the recess is formed in the recess. In a line boring bar in which a cutting blade member having a cutting blade protruding on the outer periphery of the tool body is attached so that the amount of protrusion of the cutting blade can be adjusted, an opening of the recess is provided. It is characterized in that a bridge portion connecting between wall surfaces is provided. Therefore, according to the line boring bar configured as described above, even when the concave portion must be formed on the outer periphery of the tool main body as described above, the cross-linking portion provided at the opening of the concave portion is used. By tying between the wall surfaces of the recess, it is possible to suppress the rigidity of the tool body from being impaired, and to suppress the center of gravity of the tool body at the position where the recess is formed from shifting to the opposite side to the recess, The dynamic balance of the tool main body can be maintained without largely notching the outer periphery of the tool main body on the opposite side.

Here, in particular, the above-mentioned cutting blade member has an adjusting nut at the neck like the above-mentioned fine-adjustment type cutting tool, and the protruding amount of the cutting blade is adjusted by rotating the adjusting nut with a working tool. In such a case, the bridging portion is bridged with the bottom surface of the concave portion via a gap portion, and a working tool for adjusting the amount of protrusion of the cutting blade of the cutting blade member is provided in the gap. What is necessary is just to be able to insert in the said recessed part through a part. Further, if the bridge portion is formed integrally with the tool body, the rigidity of the tool body 1 against bending and bending can be more reliably improved.

[0010]

1 to 3 show an embodiment of the present invention. The basic configuration of a line boring bar according to this embodiment is shown in FIGS. 4 to 8. FIG. Since they are the same as those of the first embodiment, the same reference numerals are assigned to common parts, and the description is simplified. That is, also in the present embodiment, a cutting edge member 6 for rough machining (not shown) and a cutting edge member 9 for finishing machining are provided on the outer periphery of the tool body 1 having a substantially cylindrical shaft shape. The cutting blade member 9 for finishing is provided with a main body 10 embedded in the tool main body 1 and a cutting blade 2B protruding from the main body 10 and provided at a tip thereof. Head 11
A fine-adjustment type cutting tool including an adjustment nut 12 interposed between the head 11 and the main body 10 to finely adjust the protrusion amount of the cutting blade 2B is used.

More specifically, in the present embodiment, the tool main body 1 is formed of a hard material such as a cemented carbide, and the cutting blade 2B is mounted on the head 11 of the cutting blade member 9. It is formed on a throw-away tip 2a detachably attached to the seat 11A. At the position where the cutting blade member 9 is attached, a recess 13 is formed on the outer periphery of the tool main body 1 so that the head 11 of the cutting blade member 9 can be accommodated. Recess 13
The main body 10 is buried in a mounting hole 13B drilled from the bottom surface 13A of the tool body 1 toward the inner peripheral side of the tool body 1.
The adjustment nut 12 is protruded so as to face the bottom surface 13A, and is detachably attached by a not-shown attachment screw or the like. Also, the bottom surface 13A of the recess 13
Is a flat surface having a rectangular shape perpendicular to the rotation axis of the adjusting nut 12 (in this embodiment, coaxial with the center line of the mounting hole 13B) O, and is directly attached to the outer peripheral surface 1A of the tool body 1 as it is. This bottom surface 13A is formed so as to intersect.
In a state where a work tool such as a spanner is hooked on the adjustment nut 12, a size capable of rotating the work tool at a required angle around the rotation axis O in a plane parallel to the bottom surface 13A is secured. Have been.

The opening of the recess 13 is formed with a bridging portion 21 connecting the wall surfaces 13C of the recess 13. That is, the broken lines in FIGS. 1 and 2 indicate that the wall surfaces 13C, 13 of the concave portion 13 opposed to each other in the longitudinal direction when the bridge portion 21 is not formed.
C (see FIGS. 6 and 7), and the crosslinked portion 21
The wall 13C is formed at the opening of the recess 13 so as to connect the walls 13C in the longitudinal direction. However, the bridge portion 21 in the present embodiment is formed integrally with the tool main body 1, that is, when the tool main body 1 is formed of a cemented carbide as described above, this cemented carbide is sintered. Since the raw material powder before the compacting is molded integrally with the part to be the tool body 1 at the time of compacting, in the present embodiment, the wall surfaces 13C, 13C is not defined as shown by the dashed line in the figure.

Here, the bridge portion 21 of the present embodiment is formed so as to open a gap 22 between the bottom surface 13A of the recess 13 and the gap portion 22 in a side view parallel to the bottom surface 13A. In FIG. 1, as shown in FIG. 1, the width W is formed along the axis O direction.
The working tool such as a wrench is sized to insert the working tool into the recess 13 through the gap 22 so that the working tool is hooked on the adjustment nut 12 as described above. In this state, it is rotatable around the axis O. In addition, the outer peripheral surface 2 of the bridge portion 21
1A is an outer peripheral surface 1A of the tool body 1 in the longitudinal direction.
In other words, as shown in FIG. 3, the cross section perpendicular to this longitudinal direction is formed in a circular cross section that is flush with the circle formed by the outer peripheral surface 1 </ b> A of the cylindrical main body 1. No. However, on the mounting hole 13B of the bridging portion 21, the main body 10 is inserted into and removed from the mounting hole 13B, and the cutting blade member 9 is detachably mounted on the concave portion 13.
Also, the head 11 having the cutting blade 2B provided at the tip is attached to the tool body 1
A through hole 21B for projecting to the outer periphery is formed.

Therefore, in the line bar configured as described above, the concave portion 13 to which the cutting blade member 9 is attached is provided.
By forming the bridging portion 21 in the opening of the tool body 1, it is possible to suppress a decrease in the rigidity of the tool body 1 due to the formation of the concave portion 13, and in particular, the radial rigidity of the tool body 1 having a cylindrical shaft shape. Therefore, it is possible to effectively suppress the bending and bending of the tool main body 1 due to the load acting on the cutting blade 2B during the processing. In addition, since the bridging portion 21 is formed in the opening of the concave portion 13 and the inside of the concave portion 13 is tightly packed, the displacement of the center of gravity of the tool body 1 due to the concave portion 13 is minimized, and the movement during rotation is minimized. Since the balance can be maintained, the notch provided on the opposite side of the concave portion 13 for maintaining the dynamic balance is also minimized, or such a notch is formed as shown in FIGS. It is not necessary to do so, and a reduction in the rigidity of the tool body 1 due to the formation of the notch can be suppressed. For this reason, according to the line boring bar having the above-described configuration, the processing accuracy of the cutting blade member 9 that performs the finishing processing by the cutting blade 2B is impaired by the bending or bending of the tool body 1 due to such a decrease in rigidity. In particular, when the cutting blade member 9 is a fine-adjustment type cutting tool as described above, and the recess 13 having a certain size must be formed to accommodate the head 11 thereof. Even if it does, it becomes possible to finish the prepared hole formed in the workpiece to a predetermined inner diameter with higher accuracy.

In this embodiment, when the above-described fine-adjustment type cutting tool is used as the cutting edge member 9 as described above,
While the adjusting nut 12 provided at the neck of the cutting blade member 9 projects toward the bottom surface 13A of the concave portion 13, a gap portion 22 is provided between the bridge portion 21 and the bottom surface 13A. A working tool such as a spanner can be inserted into the recess 13 through the gap 22. For this reason, by providing such a bridge portion 21, it becomes difficult or complicated to adjust the amount of protrusion of the cutting blade 2B in a state where the cutting blade member 9 is attached to the tool body 1, or a special operation for the adjustment is required. It is easy to rotate the adjustment nut 12 by using a spanner or the like which is a general work tool, and hooking the adjustment nut 12 on the adjustment nut 12 to rotate the adjustment nut 12. The amount of protrusion of the cutting blade 2B can be adjusted, and operability that is no different from that of the conventional line boring bar described above can be obtained.

Further, in this embodiment, the cross-linking portion 21
Are formed integrally with the tool main body 1, that is, between the bridge portion 21 and the tool main body 1, the wall surface 13 shown by a chain line in the drawing.
Since a seam along C and 13C is not formed, even if a bending or bending force acts on the tool main body 1, a break occurs from such a seam so that the bridge portion 21 is peeled off. The rigidity of the tool body 1 can be more reliably improved. Moreover, in the present embodiment, since the gap portion 22 has an oval shape in a side view and no corner portion intersecting at an angle between the tool body 1 and the bridge portion 21 is formed. Even if the bending or bending force acts on the tool body 1, no crack is generated from such a corner portion and the bridge portion 21 is not broken, and the rigidity of the tool body 1 is more reliably improved. Can be done.

In this embodiment, however, the bridge portion 21 is formed integrally with the tool body 1 as described above. However, for example, the tool body is formed from a steel round bar or the like, and is formed integrally with the tool body. For example, when it is complicated to form the concave portion after leaving the bridge portion, the portion serving as the bridge portion is formed separately from the tool main body, and a joining means such as welding or the like is used. It may be attached so as to connect between the wall surfaces of the concave portions by fastening means such as screwing. further,
In this case, if the bridge portion formed separately from the tool body and attached to the recess is formed of, for example, a material having higher rigidity than the tool body, the rigidity of the tool body in the recess can be further improved. If it is made of a material having a specific gravity different from that of the tool main body, for example, a material having a specific gravity larger than that of the tool main body, it is possible to more reliably suppress the displacement of the center of gravity of the tool main body including this bridge portion. Thus, the dynamic balance can be further maintained.

[0018]

As described above, according to the present invention,
By providing a bridging portion at the opening of the concave portion to which the cutting blade member is attached, the rigidity of the tool body at the position where the cutting blade member is attached is reduced by the concave portion, and the concave portion reduces the dynamic balance during rotation of the tool body. It is possible to prevent the tool body from being damaged, and thus it is possible to prevent the tool body from being greatly bent or bent during machining due to such a decrease in rigidity or deterioration in dynamic balance.
The pilot hole formed in the workpiece can be machined to a predetermined inner diameter with high accuracy.

[Brief description of the drawings]

FIG. 1 is a partial side view showing an embodiment of the present invention.

FIG. 2 is a partial plan view of the embodiment shown in FIG. 1 (however, the cutting blade member 9 is not shown).

FIG. 3 is a sectional view taken along line XX in FIG.

FIG. 4 is a side view showing a conventional line burring bar.

FIG. 5 is an enlarged sectional view taken along the line YY in FIG. 4;

FIG. 6 is an enlarged side view showing a periphery of a concave portion 13 of the conventional line boring bar shown in FIG.

7 is an enlarged plan view showing a periphery of a concave portion 13 of the conventional line boring bar shown in FIG. 4 (however, the cutting blade member 9 is not shown).

8 is a sectional view taken along the line ZZ in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tool main body 2 (2A, 2B) Cutting blade 6, 9 Cutting blade member 12 Adjustment nut of cutting blade member 13 Concavity 13A Bottom surface of concavity 13C Wall surface of concavity 13 21 Bridge part 22 Gap part

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Takeshi Sumi 1528 Nakashinda, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture F-term in Mitsubishi Materials Corporation Gifu Works (reference) 3C046 KK02 PP03

Claims (3)

[Claims] 1. A concave portion is formed on an outer periphery of a substantially cylindrical shaft-shaped tool main body, and a cutting blade member having a cutting blade protruding on the outer periphery of the tool main body is formed in the concave portion. A line boring bar having an adjustable amount of mounting, wherein an opening of the concave portion is provided with a bridging portion connecting between wall surfaces of the concave portion. 2. The bridge portion is bridged between the bottom surface of the concave portion and a gap through a gap, and a working tool for adjusting the amount of projection of the cutting blade of the cutting blade member is passed through the gap. 2. The device according to claim 1, wherein the device can be inserted into the recess.
Line boring bar described in. 3. The tool according to claim 1, wherein the bridge is formed integrally with the tool body.
Line boring bar described in.