JP4401495B2 - Single blade reamer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a single-blade reamer in a machine reamer, a gun reamer, or the like, and in particular, maintains a high hole machining accuracy even by high-speed cutting.
[0002]
[Prior art]
The reamer is a cutting tool used when finishing a prepared hole, and a single-blade or multi-blade reamer is selected according to the application and required processing accuracy. In general, the single-blade reamer is suitable for drilling with high accuracy such as coaxiality, roundness, and straightness, and the multi-blade reamer has an advantage that the machining efficiency can be increased by the number of blades. The reason why the single-blade reamer is excellent in hole accuracy is that there is no influence of the variation of the cutting edge due to the single cutting edge, and the cutting state is stable because the cutting force is always applied in a certain direction. To do.
[0003]
FIGS. 5 and 6 show an example of a conventional single-blade reamer, in which a reamer blade 3 is formed on the outer peripheral edge of a blade groove 2 provided in the reamer body 1. A guide pad 7 having the same diameter as that of the reamer blade 3 is usually formed on the outer peripheral surface of the reamer body 1, and the cutting force acting on the reamer blade 3 is applied to the inner wall surface of the hole being processed via the guide pad 7. It is configured to accept.
[0004]
[Problems to be solved by the invention]
One means for realizing high-efficiency machining in cutting is high-speed cutting. However, there are few examples of high-speed machining in reamer machining. In other words, the multi-blade reamer has an excellent balance during cutting, but it cannot be said that the machining accuracy is good as described above. On the other hand, in the case of a single-blade reamer, cutting is performed by applying a cutting force to the guide pad. This is because the shape of the reamer is a cross-sectional shape with a biased center of gravity on the guide pad side due to its configuration, and the shape of the dynamic balance during rotation is very poor.
[0005]
Recently, single-blade reamers that have been joined with ultra-high-pressure sintered chips such as CBN and sintered diamond to make reamer blades have also been put into practical use. Tool material properties that are suitable for If high-speed cutting is performed with a poor balance, the burnishing torque will be excessive and the hole accuracy will decrease, and the tool will be damaged or broken due to galling and seizure. In the case of a gun reamer having a long overall length and a steel pipe or the like in the middle, this problem is serious because the contact pressure of the guide pad further increases due to the deflection of the tool due to high-speed rotation.
[0006]
[Means for Solving the Problems]
The present invention has been made in view of the above-described problems, and is provided with a reamer blade by cutting out a single blade groove extending in a direction along the axis from the tip on the outer periphery of a reamer body having a round bar shape. In addition, in the one-blade reamer provided with a guide pad on the outer peripheral surface, a plurality of grooves having substantially the same shape as the blade groove are attached to the outer periphery of the reamer body. It is equally arranged in the circumferential direction together with the groove, and is arranged so that a guide pad exists at a substantially symmetrical position of the reamer blade across the axis, and further, the reamer blade And a stepped structure formed by a leading blade having a small diameter on the leading end side of the reamer body and a finishing blade having a large diameter on the trailing end side, and the groove has the same diameter as the leading blade. Forming a cutting edge, Characterized in that it is configured with a plurality of the preceding blade and one finishing cutter I.
[0007]
The center of gravity is close to the axis line by equally arranging the blade groove formed with the reamer blade and the plurality of grooves having substantially the same shape and no reamer blade in the circumferential direction on the outer periphery of the drill body. It becomes a reamer with improved balance. In addition, since the guide pad is located at the axially symmetrical position of the reamer blade, the cutting force is directly received and the cutting is stabilized. As a result, high-speed and high-precision drilling can be performed. Furthermore, by using a multi-blade leading blade and a stepped cutting blade that is finished with a single finishing blade thereafter, high-speed and high-feed machining can be performed, and high-efficiency machining is possible.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 show a single-blade reamer according to the present invention, and the reamer body 1 is an example of a straight shank having a round bar shape from the front end to the rear end. The outer periphery of the reamer main body 1 is notched with one blade groove 2 extending in the direction along the axis O from the tip, and has a reamer blade 3 on the outer periphery thereof.
[0009]
Further, a groove 4 having the same shape as the blade groove 2 is attached to the outer periphery of the reamer body 1. A plurality of grooves 4 are provided. In this embodiment, two grooves 4 are provided, and three grooves including the blade grooves 2 are equally arranged in the circumferential direction. The tip portion of the reamer body 1 provided with the groove 4 is disposed so as to recede from the tip of the reamer blade 3. A chamfer 5 is applied to the outer periphery of the tip, and the intersection ridge line 6 between the groove 4 and the outer peripheral surface is also rounded so that the outer peripheral surface acts as a guide pad 7. And the guide pad 7 exists in the symmetrical position of the axis line O of the reamer blade 3 by setting the shape of the blade groove 2 appropriately.
[0010]
Here, we introduce the results of actual measurement of dynamic balance. The single-blade reamer used for the actual measurement is made of cemented carbide having a diameter of 38 mm and an overall length of 420 mm, and the rotation speed is 2000 rotations per minute. The dynamic balance at this time is G = 420 (mm / s) in the conventional shape as shown in FIG. G = 8, which is a significant improvement. Even in actual drilling, the range of speed varies depending on the work material, but even if the reamer of the present invention cuts at a higher speed than the normal cutting speed of the work material, it can be applied to the side of the guide pad that is likely to occur in the conventional reamer. Stable processing can be obtained because seizure due to excessive load and galling due to intense burnishing are not observed.
[0011]
3 and 4 show another embodiment of the present invention, in which the same parts as those described above are given the same reference numerals. The blade portion of the reamer body 1 has a stepped configuration in which the diameter of the front end portion is reduced and the rear end side is increased. And the level | step difference is set to the magnitude | size of finishing allowance. Accordingly, the reamer blade 3 formed on the outer peripheral edge of the blade groove 2 is also a two-stepped cutting blade, the leading blade 31 that performs the intermediate finishing process in advance, and the finishing blade that performs the follow-up machining of the processing surface by the leading blade 31. 32.
[0012]
Further, the reamer main body 1 is provided with two grooves 4 having the same shape as the blade groove 3, as an example, separately from the blade groove 3, and equally distributed in the circumferential direction together with the blade groove 3. The leading edge 31 is formed on the outer peripheral edge of the groove 4 in the same manner as the leading edge 31 of the blade groove 3 in the portion having a small diameter at the tip, and a three-blade structure is formed as a whole. On the other hand, the second stage portion whose diameter is increased by the amount of the finishing allowance is a one-blade reamer formed so that the intersecting ridge line 6 between the groove 4 and the outer peripheral surface is rounded and the outer peripheral surface acts as a guide pad 7. It has a configuration. Then, by appropriately setting the shape of the blade groove 2, the guide pad 7 is disposed at a position symmetrical to the axis O of the finishing blade 32.
[0013]
In the present invention, if a tip of the reamer blade 3 or the tip of the leading blade 31 and the finishing blade 32 is joined with an ultra-high pressure sintered body chip such as CBN or sintered diamond, the tool material corresponding to high-speed cutting is obtained. It can be a single blade reamer.
[0014]
【The invention's effect】
Since the single-blade reamer of the present invention has a center of gravity in the vicinity of the rotation center and excellent dynamic balance, seizure due to an excessive load applied to the guide pad side, which is conventionally found in reamers, and galling due to intense burnish action occur. Thus, stable machining can be obtained even under high-speed cutting conditions, and the high-precision machining characteristic of the single-blade reamer is utilized. In addition, by using a stepped cutting blade, even if it is a somewhat rough pilot hole state, the leading blade will finish in the middle, leaving a constant finishing allowance, so the hole cutting accuracy with the finishing blade is higher accuracy To stabilize. Since the leading blade is multi-bladed, high-efficiency machining with increased feed can be performed.
[Brief description of the drawings]
FIG. 1 is a front view of a tip side of a single-blade reamer of the present invention.
FIG. 2 is a reduced side view of FIG. 1;
FIG. 3 is a front view of the tip side of another single-blade reamer according to the present invention.
4 is a reduced side view of FIG. 3;
FIG. 5 is a front view of the tip side of a conventional single-blade reamer.
FIG. 6 is a reduced side view of FIG. 5;
[Explanation of symbols]
2 Cutting groove 3 Reaming blade 31 Leading blade 32 Finishing blade 4 Groove 7 Guide pad O Axis

Claims (2)

On the outer periphery of the reamer body in the form of a round bar, a reamer blade is provided by cutting out one blade groove extending in the direction along the axis from the tip, and one sheet provided with a guide pad on the outer peripheral surface. In the blade reamer,
A plurality of grooves having substantially the same shape as the blade grooves are provided on the outer periphery of the reamer main body, and the grooves are equally distributed in the circumferential direction together with the blade grooves, and the reamer blades substantially sandwich the axis. A single-blade reamer, characterized in that the guide pad is disposed in a symmetrical position. The reamer blade has a stepped configuration formed by a leading blade having a small diameter on the front end side of the reamer main body and a finishing blade having a large diameter on the rear end side, and the groove has the leading blade. The single-blade reamer according to claim 1, wherein a cutting blade having the same diameter is formed, and has a plurality of leading blades and one finishing blade.

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