JPS5947119A - Two-step edge reamer - Google Patents

Abstract

PURPOSE:To equip a reamer with such factors to be required as dimensional accuracy, roundness, etc. by giving its minor diameter edge a function to carry out machining with good cutting performance and the major diameter edge, with good finishing performance and by allowing them to work cooperatively. CONSTITUTION:This reamer is equipped with an edge of major diameter 2a and another one of minor diameter 2b concentrically. The chamfering edge 3 of each of them 2a, 2b is so designed that the distance H from the end face of reamer to the cutting edge corner 4 of the edge 2a is greater than that for the edge 2b, that a step is provided in the axial direction, and that the edge 2b precedes in the axial direction for a distance corresponding to H-h. Thus the roundness of an finished hole is very good. That is to say, the edge 2b enhances the cutting performance while the edge 2a, the finishing performance, and they work in preparing better condition for each other.

Description

[Detailed Description of the Invention] Reamers are widely used as drilling finishing tools due to their simplicity, but the performance requirements required of reamers include hole dimensional accuracy, hole roundness, and hole diameter. There are many variations such as straightness and surface roughness of the hole wall, but some of them are one-sided. It also has a self-contradictory property in that improving one will worsen the other, and there has been no reamer that completely satisfies these requirements. In view of the current state of reamers, the present invention aims to develop a reamer that solves all of these problems at once.

The outer periphery of the main body 1 has a large angle within the range of the so-called axial direction from the axis Ax to the demarcation line between the radial direction orthogonal to the axis A and X, that is, the angle of 45 degrees with respect to the axis Ax. The diameter blade 2a and the small diameter blade 2b are cut concentrically and integrally. FIGS. 1 and 2 show a first embodiment, in which the large-diameter blade 2a and the small-diameter blade 2b are parallel to the axis Ax. The radius r of the large diameter blade 2a is the radius r of the small diameter blade 2b.
', and the radius difference d is normally formed to be about 0.02 to 0.005 mm, but its value is not specific. Large diameter blade 2
The tips of the small diameter blade a and the small diameter blade 2b are each chamfered.
fer) is applied to form a chamfered edge groove, but the chamfer angle ch of the large diameter blade 2a is smaller than the chamfer angle Ch of the small diameter blade 2b. The distance I to 4 is also larger than that of the small diameter blade 2b.

Therefore, when drilling, the small-diameter blade 2b drills the small-diameter hole first, and the large-diameter blade 2a lags behind by a distance of I-I-h, shaving only the value of d mentioned above, and then drilling. 2
It is carried out in stages. In order to make the distance H from the reamer end face 5 of the large-diameter blade 2a to the cutting edge corner 4 larger than that of the small-diameter blade 2b, the chamfer angle ch is set to the large-diameter blade 2a as in the second embodiment shown in FIG. The chamfering amount 6 may be applied to the large diameter blade 2a and small diameter blade 2b by setting the same angle to the small diameter blade 2b.

R is the radial angle (Radial Lake), which is the angle formed by the rake face f with respect to the radius line connecting the axis A If it is a positive angle, it is a positive angle.
'e), and if it is tilted backwards, it is a negative angle (Negative
e), when the radius line and the rake face f are aligned on a line, the radial rake angle R is zero. In this regard, the first embodiment of the present application is characterized in that the large-diameter blade 2a has a negative radial rake angle, and the small-diameter blade 2b has a positive radial rake angle, as shown in FIG. It is true. The functional characteristics of the cutting edge of a reamer are as shown in Figures 6 and 7. When the cutting force P is applied and the rake angle is square, the cutting edge is deflected as shown by the dotted line in Figure 6. - Rotational circumference R drawn when there is no load
There is a tendency for the cutting edge to protrude beyond the 0 and the drilled hole becomes enlarged, and when the rake angle is negative, the cutting edge becomes smaller than the rotational circumference RO of the reamer with no load, as shown by the dotted line in Figure 7. 1st and 6th cases where the hole drilled by
For ease of drawing and understanding, Figure 7 has been explained using the positive and negative values of the rake angle in the radial direction; - The issue of the rake angle must be discussed in terms of the rake angle from the T direction perpendicular to the chamfered edge 3, that is, the true rake angle (tanT). The tendency of expansion and contraction of R is the same as that described for the radial rake angle R described above.

The true rake angle (tanT) is determined by the radial rake angle and the chamfer angle when the large-diameter blade 2a1 and the small-diameter blade 2b are parallel to the axis Ax as in the first and second embodiments. ista
nRXcosCh=tanT·−C Formula 1].

Since the radial rake angle R of the large-diameter blade 2a is formed to be a negative angle as described above, the value of tanR in Equation 1 is calculated as a negative number. The true rake angle (tanT) is a negative angle. Since the radial rake angle of the small-diameter blade 2b is formed to be a regular angle as described above, the value of tag in Equation 1 is calculated as a positive number, so ta and nT are positive numbers, and therefore, the rake angle of the small-diameter blade 2b is The true rake angle (t
anT) forms a conformal angle.

When working with a reamer, there are issues with chip disposal depending on the type of material to be drilled, the presence or absence of a notch in the hole to be drilled, the direction of chip ejection (through hole or blind hole), and the spindle of the machine tool used. The reamer blade may be twisted to the left or right depending on the conditions of use, such as the degree of looseness.

FIG. 4 shows the reamer of the present invention twisted to the left, and FIG. 7 shows it twisted to the right.

Of course, since both are embodiments of the present invention, the twist angle is within the axial angle range mentioned at the beginning, and the reamer blade is formed integrally with the large-diameter blade 2a and the small-diameter blade 2b concentrically. The chamfer is applied so that the distance I from the reamer end face 5 of the large-diameter blade 2a to the cutting edge corner 4 is larger than the deflection of the small-diameter blade 2b, J:p. Note that the two-dot chain line in both figures indicates the rotation locus of each blade, although the distinction between the large-diameter blade 2a and the small-diameter blade 2b is omitted.

When the reamer blade is twisted in this manner, if the reamer blade is twisted to the left as in the fifth embodiment shown in FIG.
Lake ) acts as a negative angle, and in the case of right-handed twist as in the fourth embodiment shown in FIG. 5, the axial rake angle A acts as a positive angle. The positive and negative changes to the axial rake angle exhibit exactly the same tendency with respect to the expansion and contraction of the drilled hole as in the case of the previously described radial rake angle shown in FIGS. 6 and 7. However, as mentioned earlier, the cutting edge of the reamer is at the chamfered edge 3, so the problem with the rake angle for the reamer is the T which is perpendicular to the chamfered edge 6.
We must discuss the positive and negative aspects of the directional rake angle, that is, the true rake angle (tanT), and as already mentioned, the tendency of hole enlargement and contraction is exactly the same as when the radial rake angle is 1. .

The true rake angle (tanT) when the axial rake angle A is provided is the radial rake angle R and the axial rake angle A.
is determined by the chamfer angle ch, and the relationship is tanRx C08c
h+tanAxsinCh=tanT...[Formula 2].

If the axial rake angle A is a left-handed helix and is a negative angle, tanA will be calculated as a negative number, but if the radial rake angle R is selected to be an appropriate positive angle, tanT will be set to a positive number and the true rake angle (jan'l
It is extremely easy to make the radial rake angle R a positive angle of 10°. If we take, tanlR=tan 1 0°= 0.1
7 6 3, tanA=jan 6°=0. ID51
, cos Ch = cos 3 0°
=0.866, s i n Ch = s i n
3 0° = 11.5 0 0 0, so 0.1
763X0.866-1-(-〇, 1051X0.50
00)=Q, 1002Φtan5°42', and the true rake angle (tan T ) can be made a regular angle.

If the rake angle in the axial direction is right-handed and has a positive angle, tanA will be calculated as a positive number, but if the radial rake angle is selected to be an appropriate negative angle, tanT will be set to a negative number and the true rake angle (jan'
l") can be a negative angle, and using the angles listed above as they are and calculating with tanR as a negative number and tanA as a positive number, we get -0,1763X0.866-1-0.1051
X0.5000 = -0,1002 crystal -jan5° 42, and the true rake angle (tan T) can be made negative 1° In this way, the reamer blade shown in Figures 4 and 5 In the third and fourth embodiments in which the large diameter blade 2 is twisted,
The true rake angle (tanT) with respect to the chamfered blade 3 of a is a negative angle, and the true rake angle (tanT) with respect to the chamfered blade 6 of the small diameter blade 2b is set as a negative angle.
n T ) is a conformal angle.

Regarding the relationship between formula 1 and formula 2, in the case of formula 1, the reamer
Since the blade is a straight blade parallel to the axis Ax and the axial rake angle A is zero, tanRXcosch-4-ta in Formula 2
t a n A X5inch in nAXinch
becomes zero and only tanRXcosch remains as Equation 1, and Equation 1 is essentially the same as Equation 2.

If the above is summarized, the constituent elements of the present invention are (1)...1,
A large-diameter blade 2a with a large radius r and a small-diameter blade 2b with a small radius r' are provided concentrically and integrally on the 1-mer, and (2)... how to chamfer the large-diameter blade 2a and the small-diameter blade 2b. (3) A chamfered edge 3 is formed to create a step in the axial direction by making the distance H from the end face 5 of the reamer to the cutting edge corner 4 of the large-diameter blade 2a larger than that h of the small-diameter blade 2b. ...The most important requirement is that the true rake angle (tanT) of the large-diameter blade 2a with respect to the chamfered blade 3 is a negative angle, and the true rake angle (tanT) of the small-diameter blade 2b with respect to the chamfered blade 5 is a negative angle. Part 3 of making it a right angle
By configuring it like this, the conventional reamer
It solved all the difficult problems that had been asked of the company all at once.

The primary performance requirement for a reamer is good dimensional accuracy, including the roundness of the hole, but in order to obtain good dimensional accuracy, a good prepared hole is first of all necessary. However, it is necessary that the dimensional difference between the reamed hole and the prepared hole be small, and that the reaming allowance be small. However, in practice, for example, even if a 98 mm pilot hole is made for a 10 mm reamed finished hole and the reaming allowance is set to 0.1 mm IJ on one side, the pilot hole drilled with a drill will not be very accurate. The concentricity of the center of the pilot hole and the axis of the reamer (alignment)
If there is a slight deviation of the reamer, a so-called black scale will be left behind, increasing the defective rate and making it impractical. Therefore, the pilot hole is usually used with a diameter difference of 0.5mm IJ or more from the reamed hole. Management of the prepared hole during reaming work was an important and difficult problem. However, if the pilot hole diameter is made smaller and the reaming allowance is increased, the cutting resistance applied to the reamer increases and the roundness worsens, so attempts have also been made to reduce the cutting resistance by setting the true rake angle (tanT) of the reamer to a square angle. In this case, the reamer not only enlarges the hole and deteriorates the accuracy of the hole dimensions as mentioned above, but also causes the reamer to enter a larger hole by itself. Polish the hole wall surface with the outer periphery of (
Another mission imposed on the reamer, which is to perform burnishing, does not work, resulting in a performance defect in that good surface roughness of the hole wall surface cannot be obtained. Reamer on the contrary
If the true rake angle (tanT) is made negative, the hole will shrink and the reamer will try to force its way into the smaller hole. The action should be sufficient and the surface roughness of the hole wall surface should improve, but things did not go so well and the cutting force increased and the roundness of the hole deteriorated, and a large amount of reaming allowance had to be taken. Vanilla Song Torque (Burni)
The reamer is too big
This causes a fatal defect in that the reamer is strongly hugged by the hole wall, leading to breakage of the reamer. Furthermore, since the reamer cuts with the chamfered blade 3, it has little ability to correct the curvature of the prepared hole, and since reaming follows the curvature of the prepared hole, it is almost impossible to obtain a hole with good straightness. It was possible.

In this way, many of the performance requirements for reamers are self-contradictory, and even though reamers have become widely used, they are unable to meet all requirements, and major users have to strictly adhere to them. Focusing on the performance of the reamer with respect to the requirements that must be met, and overlooking to some extent the requirements that should be tolerated, the company procures a reamer for its own use separately by setting dimensional tolerances for the reamer for its own use. The current situation was that

The chamfering method of the blade 2a and the small diameter blade 2b is changed to form a chamfered blade 3, and the large diameter blade 2a is cut from the end face 5 of the reamer.
The distance to the cutting edge corner 4 of the small diameter blade 2b is made larger than that of the small diameter blade 2b to create a step in the axial direction.
-h value in the axial direction, and since the true rake angle (tanT) of the small diameter blade 2b is a positive angle to improve cutting performance, the reamer-finished hole and the drill Small diameter blade 2b even if the diameter difference with the hole is large and the reamer allowance is large
The small-diameter hole is drilled first with a small cutting resistance, and since the large-diameter blade 2a and the small-diameter blade 2b are concentric, the small-diameter hole that was drilled first by the small-diameter blade 2b is drilled by the large-diameter blade 2a. Concentricity (
Alignment) provides a good pilot hole, and the large-diameter blade 2a exposes only the minute radius difference d between r-r' (5
) Since only drilling is required, the cutting resistance applied to the large-diameter blade 2a is small, and the roundness of the finished hole is extremely good. It also depends on the hole diameter, but a pilot hole with a smaller diameter of 1 mm to 2 mm compared to the finished hole size is sufficient. It also has the advantage of freeing you from the complicated work of managing pilot holes since it is created.

Next, the true rake angle (ta) of the large diameter blade 2a with respect to the chamfered blade 3
Since nT) is formed at a negative angle, the radius difference d can be shaved off rather than shaving, and as explained in detail earlier, the true rake angle (jan'1)
1. ”) is a negative angle, the hole tends to shrink, and the reamer will enter a hole smaller than itself, but the large diameter blade 2
Since the reaming allowance of a is a minute amount of the radius difference d, a moderate burnishing effect is exerted between the hole wall surface and the outer periphery of the large diameter blade 2a, polishing the hole wall surface and crushing the cutting marks. The surface roughness of the hole wall surface is extremely good 1, and the large diameter blade 2
Since the reaming allowance in a is minute, there is no chance of breakage due to excessive burnishing torque. Furthermore, it is sufficient that the axial step 1-1-h between the cutting edge corner 4 of the large diameter blade 2a and the cutting edge corner 4 of the small diameter blade 2b is slightly larger than the feed amount per revolution of the reamer. As soon as the cutting edge corner 4 of the small-diameter blade 2b makes a hole, the large-diameter blade 2a immediately starts reaming, and as described above, the large-diameter blade 2a has a burnishing effect with the hole wall surface, and the large-diameter blade 2a has an umbrella hole. Since it is held against the wall surface, the small diameter blade 2b plays the role of a guide for the drilling work, so the small diameter blade 2b does not follow the curvature of the prepared hole of the drill, but corrects the curvature and drills from time to time. Therefore, the straightness of the finished reamed hole is incomparably better than that of conventional general-purpose reamers.

As shown above, the reamer of the present invention has the small diameter blade 2b that provides good cutting performance, and the large diameter blade 2a that provides good finishing performance.
Moreover, if one provides a good pilot hole to the other, the other will become a good guide for the other, so they mutually create good conditions for the other and function in a mutually supportive manner. The reamer of the present invention is truly a unique and excellent reamer that satisfies all of the required self-consistent performance requirements.

As an experimental example, a 25 mm diameter carbide IJ-mer of the present invention was used, a hole depth of 50 mm in the material to be drilled was 550C, a pilot hole drill diameter was 24 mm, a mechanical branch type drilling machine was used, and a wet drilling method was used. Cutting speed 165m/min under conditions
, using cutting conditions of feed 0.2/rev %, hole circularity 2 microns, hole diameter: +0 at the entrance of the hole, +0.01 mm at the exit, surface roughness of the hole 3S1.
The straightness of the hole was 5 microns.

Figure 8 shows another special embodiment in which the small-diameter blade 2b is not chamfered, and the end face 5 of the IJ-mer is turned toward the center of the reamer.
The blade is attached with a reverse slope of θ, and the cutting edge of the small diameter blade 2b is formed into an end mill blade 4'.
The large-diameter blade 2a is chamfered and the true rake angle (tanT) with respect to the chamfered blade 6 is formed as a negative angle, which is the same as on each side described above, and the large-diameter blade 2a and the small-diameter blade 2b are on the right or Of course, there are cases where it is twisted to the left. The rake angle of the end mill blade 4' is such that at least one of the radial rake angle R and the axial rake angle A is a regular angle.

This embodiment is used when, for example, a hollow cylindrical material to be drilled is diametrically penetrated and opposing holes are bored.

As mentioned above, on each side, the large-diameter blade 2a, which is held in the hole wall by the burnishing torque, acts as a guide and helps the small-diameter blade 2b to drill straightly, resulting in good straightness. A reamed hole was obtained, but when the material is hollow, the guiding action of the large diameter blade 2a does not work in the hollow part, and when the opposite hole is reached, the small diameter blade 2b flows cleanly into the prepared hole. Straightness, that is, concentricity of opposing holes could not be obtained. Therefore, if the cutting edge of the small-diameter blade 2b is formed into an end mill blade 4' with a reverse slope of θ as in this embodiment, when the small-diameter blade 2b reaches the opposing hole, it will correct the pilot hole by itself without following the pilot hole and drill the hole. Therefore, we were able to successfully ream the opposing holes with a concentricity of 1 micron.

In this way, the reamer of the present invention solves all the requirements in drilling work that were considered impossible with conventional reamers, and has a wide range of applications. It is an invention called a dog that contributes to improvement.

There is no restriction on the number of large-diameter blades 2a and small-diameter blades 2b in the present invention, and there is a special reason why the large-diameter blades 2a and small-diameter blades 2b must be arranged alternately as shown in the attached figures. There is nothing.

[Brief explanation of drawings]

Figure 1 is a front view of a first embodiment of the invention Figure 2 is a bottom view (end view) of Figure 1 Figure 6 is a front view of a second embodiment of the invention Figure 4 is a third embodiment of the invention 5 (front view of the fourth embodiment of the inventive invention) FIGS. 6 and 7 are partially enlarged views of FIG. ...Large diameter blade 2b...
Small diameter blade 6... Chamfered blade 4... Cutting edge corner 5.
...One end face of the reamer 6 - Chamfer amount Ax...Axis center r...Radius of large diameter blade r'...Radius of small diameter blade d...Radius difference ■(...Cut of large diameter blade Height of the blade corner h... Height of the cutting edge corner of the small diameter blade ch... Chamfer angle f... Rake face 1t... Radial rake angle A... Axial rake angle T...・True rake angle direction T'%e...Rotation direction Ro...
・Rotation locus of cutting edge corner 4'... End mill blade θ... Reverse gradient collection Fig. 2 Rod Fig. 7 Go to Rem-

Claims (1)

[Claims] 1. On the outer periphery of the reamer main body (1), there is a demarcation line between the axis (Ax) and the radial direction orthogonal to the axis (Ax), that is, the axis (Ax). A large-diameter blade (2a) with a large radius (r) and a small-diameter blade (2b) with a small radius (r') are concentrically and integrally cut at an angle within the so-called axial range of up to 45 degrees. The chamfering mode of the chamfered blade (3), which is formed by chamfering the tips of the large-diameter blade (2a) and the small-diameter blade (2b), is the large-diameter blade (2a) and the small-diameter blade (2b). When installed differently, the distance (H) from the end face (5) of the reamer to the cutting edge corner (4) of the large diameter blade (2a) will be larger than that (h) of the small diameter blade (2b). The true rake angle (jan 'J,') for the chamfered blade (3) from the T direction perpendicular to the chamfered blade (3) is
The axial rake angle (A) formed by the large diameter blade (2a) and the small diameter blade (2b) with respect to
4) The true rake angle is calculated by arranging the radial rake angle (R) formed by the rake face (f) and the chamfer angle (ch) with respect to the radial line connecting the A two-stage row reamer 62 characterized in that (tanT) is configured to form a negative angle for the large-diameter blade (2a) and a positive angle for the small-diameter blade (2b).The large-diameter blade (2a) and the small-diameter blade The chamfering mode of the chamfering blade (3) formed at the tip of (2b) is constructed so that the chamfering angle (Ch) of the large diameter blade (2a) is smaller than the chamfering angle (ch) of the small diameter blade (2b). Then, the distance (1-
1) is larger than that (h) of the small diameter blade (2b).
Membrane Force Reamer-6 5 The chamfer angle (Ch) is the chamfering mode of the chamfering blade (3) formed at the tips of the large-diameter blade (2a) and the small-diameter blade (2b).
Both 2a) and the small diameter blade (2b) are equiangular,
The amount of chamfering (6) is made smaller for the large diameter blade (2a) and smaller for the small diameter blade (2b). ) 2-stage H reamer-6 4-reamer body according to claim 1, characterized in that the distance (11) to the small diameter blade (2b) is larger than that (l]) of the small diameter blade (2b). (1) On the outer periphery, from the axis (A, x) to the radial direction perpendicular to the axis (Ax) and the axis (A x
), that is, the angle within the so-called axial range of up to 45 degrees with respect to the axis (A, X'), and the large diameter blade (2a) with a large radius (r) and the Small diameter blade (
2b) are cut concentrically and integrally, the large diameter blade (2a) has its tip chamfered at the chO chamfer angle to form a chamfered blade (3), and the small diameter blade (2b) has a chamfered edge at its tip. Lid! The blade is attached with a reverse slope of θ to the end face (5) of the reamer without applying any sharpening, and the cutting edge is formed into an end mill blade (4), and the chamfered blade (3) of the large diameter blade (2a) is ) The true rake angle (tanT) for the chamfered edge (3) from the T direction perpendicular to
Large diameter blade (2a) small diameter blade (2b) relative to the axis (A x )
and the rake face (f) relative to the radius line connecting the axis (A,
) and the chamfer angle (Ch
) are arranged based on the following formula % formula % so that the true rake angle (tanT) of the large diameter blade (2a) with respect to the chamfered blade (3) forms a negative angle 1, and the small diameter blade For (2b), the rake face (f) is relative to the radius line connecting the axis (A x ) and the end mill blade (4).
The radial rake angle (R) and the axial rake angle (
A) A two-film force reamer 8 characterized in that at least one of the two membranes is configured to form a right angle with A).