JP2000354912A - Indexable reamer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid interference of a cutting blade with a guide member by sliding the cutting blade in the direction of shaft center of a tool main body by making an inclined surface of a countersunk head screw abut on the V-shaped inclined surface formed directly on the cutting face of the cutting blade, and tightening the countersunk trim head screw. SOLUTION: A countersunk trim head screw 5 which is a left-handed screw and a clamp screw is screw-fixed toward the shaft center of a tool main body, and the inclined surface of the screw head lower surface is made to abut on the cutting face of a cutting blade 2 to fix the cutting blade 2. Preferably the angle α made between the base 2c of the cutting blade 2 and the V-shaped inclined surface 2b connected thereto along the cutting blade is equal to or smaller than 10 deg.. The inclined surface 5a of the head lower surface of the countersunk trim head screw 5 is engaged with a recessed made by the V-shaped inclined surface 2b by tightening the screw 5, thereby sliding the cutting blade 2 in a mounting groove 3 in the direction of the shaft center of the tool main body 1. Since the screw 5 is left-handed, at the time of unclamping, the cutting blade 2 is let out toward the tip and detached.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reamer in which at least one cutting blade is exchangeably mounted on an outer peripheral portion of a tip end of a tool body, and provided with adjusting means for finely adjusting a radial position. Regarding indexable reamers.

[0002]

2. Description of the Related Art In a reamer in which a cutting blade is replaceable, as a clamping mechanism of the cutting blade, a clamp claw is screwed to a tool body and provided on the clamp claw and the tool body by utilizing the fastening force. Between the mounting grooves of the cutting blade,
It is a well-known technique to fix the cutting blade. When the diameter of the reamer is increased, a method is also known in which the mounting bolt penetrates a wide cutting blade and is directly screwed to the tool body.

If the cutting blade is worn, it may be used after re-grinding it. However, even if the cutting blade is mounted at the original position on the tool body, the finishing diameter becomes small, so an adjusting means is required.
The adjusting means includes a method of inserting a pin having a bevel at the tip into an adjusting hole provided in the tool body to abut against the side surface of the cutting blade and driving it in with an adjusting screw, or an adjusting hole provided in the tool body. Then, a method of inserting a steel ball into contact with the side surface of the cutting blade and driving it in with an adjusting screw is known.

Japanese Patent Application Laid-Open No. 52-122996 proposes a technique in which a cutting blade is fixed using a clamp claw suitable for a relatively small-diameter reamer, and the finished diameter is adjusted with a pin having a slope at the tip. Have been. FIG. 5 is a cross-sectional view of the clamping mechanism of the cutting blade, and FIG. 6 is a cross-sectional view of the adjusting mechanism.

In FIG. 5, reference numeral 101 denotes a tool body.
The guide member 102 is press-fitted at a plurality of locations on the outer periphery.
The cutting blade 103 has the bottom surface of the cutting blade 103 seated in the mounting groove 104, and the clamp claw 105 abuts the notch 103b provided on the rake face 103a. The clamp claw 105 is screwed into one of the reverse screws 107, screwed into the screw hole 106 of the tool body 101 with the other of the reverse screws 107, and fixed by the fastening force.

In FIG. 6, the fixing position of the cutting blade 103 is adjusted at a position slightly deviated from the position of the clamp claw 105 on the side surface 103c of the tool main body of the cutting blade 103 on the axis side of the tool main body. The slopes 109a of the adjustment pins 109 to be inserted into the plurality of adjustment holes 108 are brought into contact with each other, and the finishing diameter is adjusted by driving in the adjustment screws 110 from the rear ends of the adjustment pins 109.

[0007]

In the above-mentioned prior art,
As the finishing diameter of the reamer becomes smaller, the clamp claw 105
And the nail stiffness decreases. Increasing the number to compensate for this will increase the cost of parts and increase the number of adjustment steps.
In addition, since the clamp claw and the adjustment screw are separate bodies, the clamp claw freely rotates around the axis of the adjustment screw, and the fixing position of the clamp claw is automatically set to the optimum position with respect to the notch of the cutting blade. There is no guarantee that it will fit. The present invention provides a throw-away reamer having a small finishing diameter and a small number of components for securely fixing the cutting blade even when the diameter is 8 mm or less.

[0008]

SUMMARY OF THE INVENTION In a reamer having a replaceable cutting blade, a countersunk screw having at least one left-hand screw on a rake face of the cutting blade inserted into a mounting groove of the cutting blade. Abutting using the slope of the lower surface of the head.

[0009] More preferably, a continuous V-shaped slope along the cutting edge having an angle α of 10 ° or less with the rake face of the cutting edge blade with which the slope on the lower surface of the head of the flat head screw contacts. Alternatively, the present invention provides a clamping mechanism which is effective for a reamer having a relatively small finishing diameter, in which at least one spherical or conical dimple is formed.

The angle θ at which the bottom surface of the cutting blade intersects with the axis of the flat head screw extends in the outer peripheral direction of the reamer,
It is preferable to set θ in the range of 15 ° to 40 °.

[0011] The hardness of the flat head screw, even if it is divided, the slope hardness of the lower surface of the head is preferably heat-treated to HRC 47-60.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a side view in which a cutting blade is fixed to a tip of a tool body of a reamer. Further, FIG. 2A shows a clamping mechanism diagram of the cutting blade in the XX section in FIG. 1, and FIG. 2B shows an adjusting mechanism diagram of the cutting blade in the YY section.

In FIG. 1, reference numeral 1 denotes a tool main body, and a cutting blade 2 is inserted from a tip end of the tool main body 1 into a mounting groove 3 formed by a milling machine or an end mill. 4
Is a positioning pin of the cutting blade 2. A left-hand countersunk screw 5 serving as a clamp screw is screwed substantially toward the axis of the tool body 1, and the inclined surface on the lower surface of the screw head is brought into contact with the rake face of the cutting blade 2. Fix 2 Reference numeral 6 denotes a chip pocket at the tip, and an arrow 8 indicating the tightening direction of the countersunk screw 5 is engraved on the axial chip pocket 7. A plurality of guide members 9 made of a cemented carbide, a cBN sintered body, a diamond sintered body, etc.
It is pressed into 0 and locked. The guide member 9 has a function of preventing eccentricity, vibration and the like of the reamer.

As shown in FIG. 2A, the clamping mechanism directly removes the slanting surface 5a on the lower surface of the head of the countersunk screw 5 by omitting the clam claw which is a conventional means of the prior art. 2a. In other words, the cutting edge in the mounting groove 3 is formed by making contact with the continuous V-shaped inclined surface 2b along the cutting edge having an angle α of 10 ° or less with the bottom surface 2c and further tightening the countersunk screw 5. The blade 2 is slid in the axial direction of the tool body 1. When the angle α is set to 10 ° or more, the wedge effect sandwiched between the inclined surface 5 a on the lower surface of the head of the flat head screw 5 and the mounting groove 3 is not preferable.

The angle θ at which the bottom surface 2c of the cutting blade 2 intersects with the axis of the countersunk screw 5 is an angle that spreads in the outer peripheral direction of the reamer, and is set in the range of θ = 15 ° to 40 °. preferable. As can be seen from FIG. 2A, when the slope 5a from the head of the flat head screw 5 is brought into contact with the vicinity of the bottom of the V-shaped slope 2b, the wedge effect is easily exerted. When the angle θ is equal to or less than 15 °, the chip pockets 7 become small and prevent smooth chip discharge. Also, as the bottom surface 2c of the cutting blade 2 and the axis of the countersunk screw 5 approach in a direction parallel to each other, the angle α of the V-shaped slope 2b of the cutting blade 2 is constant. The angle of the slope 5a on the lower surface of the head is also JIS B 111
1 It is desirable to set the angle smaller than the countersunk angle of 90 ° specified in “Cross-recessed screw”. When the angle θ is 40 ° or more, the chip pocket 7 becomes large, but for the same reason, the countersunk angle of the countersunk screw 5 approaches 90 °, the head diameter of the countersunk screw 5 increases, and the strength of the head increases. Run out.

The flathead screw 5 is preferably set to a predetermined hardness by heat treatment. In an attempt, a flat head screw 5 made of nickel chromium molybdenum steel (SNCM630) was subjected to a heat treatment of quenching and tempering to a hardness of HRC 40-4.
When the clamping operation shown in FIG. 2A was repeated with respect to the one set to 5, the slope 5a on the lower surface of the head of the flathead screw 5 was worn around 20 times. Therefore, an alloy tool steel (SKD11) having a high carbon content is subjected to a heat treatment to increase the hardness to HRC.
The above clamping operation was repeated 50 times with the flathead screw 5 set at 48 to 58, but only slight abrasion was observed. Therefore, the slope 5a on the lower surface of the head of the flathead screw 5 is worn,
In order to prevent deformation, if the hardness is set in the range of HRC 47 to 60, the frequency of replacing the countersunk screw 5 can be reduced.

The clamping mechanism according to the present invention uses at least one flat head screw
However, since it only needs to be attached and detached toward the axis of the tool body 1 while making contact with the tool body 1, interference with the guide member 9 can be avoided with a margin, and the structure is suitable for a relatively small-diameter reamer. Further, since the countersunk screw 5 is a left-handed screw, the cutting blade 2 is fed to the shank side behind the tool body 1 at the time of clamping as shown in FIG. The attachment and detachment of the blade 2 becomes simple.

As shown in FIG. 2B, the adjusting mechanism of the cutting blade is provided with the mounting groove 3 at a position which does not interfere with the clamping mechanism.
The steel ball 12 is placed in the adjustment hole 11 that intersects with the cutting blade 2 and is brought into contact with the side surface of the cutting blade 2. The adjusting screw 13 is further tightened to slide the cutting blade 2 in the outer peripheral direction. The above is one example of the adjusting mechanism of the cutting blade, but usually, it is preferable to provide a plurality of positions.

FIG. 3 is a plan view of the cutting blade 2 having a continuous V-shaped slope along the cutting edge, and FIG. 4 is a view of the cutting blade 2 having a plurality of spherical or conical dimples. FIG. In FIG. 3, 2b is a continuous V-shaped slope along the cutting edge. As shown in the AA section,
It is preferable that the angle α formed by the bottom surface 2c and the slope 2b is 10 ° or less. The inclined surface 5a on the lower surface of the head of the countersunk screw 5 engages with the recess formed by the V-shaped inclined surface 2b, and the countersunk screw 5 is tightened further. 1 slide in the axial direction.

In FIG. 4, reference numeral 2d denotes a spherical or conical dimple. As can be seen from the BB cross section, the function and effect of the dimple 2d are exactly the same as those of the V-shaped slope 2b. The installation position of the dimple 2d is preferably formed slightly larger than L1 and L2 based on the end face of the positioning pin 4 shown in FIG. When the cutting blade becomes smaller, the cutting blade 2 is initially positioned at a position separated from the positioning pin 4 even if the cutting blade 2 is abutted against the positioning pin 4 and clamped, and receives the thrust of the tool body 1 during cutting.
May move to the positioning pin 4 side.

[0021]

According to the present invention, the clamping mechanism of the cutting blade is applied to the V-shaped slope formed directly on the rake face of the cutting blade by omitting the crumb claws which are conventional means of the prior art. The cutting blade is slid in the axial direction of the tool body by contacting and tightening the countersunk screw, so that interference with the guide member can be avoided with a margin and a relatively small diameter Suitable for reamers. further,
Since the countersunk screw is a left-handed screw, the cutting blade is sent to the shank side behind the tool body during clamping, and is fed to the tip side during unclamping, so that the cutting blade can be easily attached and detached.

[Brief description of the drawings]

FIG. 1 is a side view of a tip portion of a tool body of a reamer of the present invention.

FIG. 2A is a diagram illustrating a clamp mechanism of the present invention, and FIG. 2B is a diagram illustrating a clamp mechanism.

FIG. 3 is a plan view of a cutting blade having a continuous V-shaped depression of the present invention.

FIG. 4 is a plan view of a cutting blade having a spherical or conical dimple of the present invention.

FIG. 5 is a diagram of a conventional clamping mechanism.

FIG. 6 is a diagram of a conventional clamping mechanism.

[Description of Signs] 1 Tool main body 2 Cutting blade 2b Continuous V-shaped slope 2d Spherical or conical dimple 3 Mounting groove 4 Locating pin 5 Countersunk screw 5 a Countersunk face of a countersunk screw 6 Tip chip pocket 7 Shaft chip pocket 8 Arrow 9 Guide member 10 Insertion groove 11 Adjustment hole 12 Steel ball 13 Adjustment screw

Claims (4)

[Claims] 1. A head of a countersunk machine screw having at least one left-hand screw on the rake face side of a cutting blade inserted into a mounting groove of the cutting blade in a reamer having a replaceable cutting blade. A throw-away reamer characterized by contacting and clamping the lower slope. 2. An angle α formed between the rake face of the cutting blade and the bottom face, which is contacted by the slope of the lower face of the head of the flat head screw.
The indexable reamer according to claim 1, wherein a continuous V-shaped inclined surface along a cutting edge of not more than 10 ° or at least one spherical or conical dimple is formed. 3. The angle θ at which the bottom surface of the cutting blade intersects with the axis of the countersunk screw extends in the outer circumferential direction of the reamer and is set in the range of θ = 15 ° to 40 °. The throw-away reamer according to claim 1 or 2, wherein: 4. A flat head screw having a hardness of HRC 47-60.
The indexable reamer according to any one of claims 1 to 3, wherein: