JP2009214197A - Reamer and reaming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reamer and a reaming method capable of effectively suppressing generation of a burr. <P>SOLUTION: While cutting 40% or more of portion of the whole machining allowance T0 of a lower hole 8 by a first cutting blade, remained machining allowance T2, i.e., 60% or less of mounting allowance T2 of the whole mounting allowance T0 of the lower hole 8 is cut by a second cutter blade 7. Since it is publicly known that suppression effect of the burr is high as the machining allowance is small, generation of the burr can be effectively suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement of a reamer and a reamer processing method.

  In general, a valve body of an automatic transmission of an automobile has a spool hole in which a valve is fitted in an aluminum alloy block. Since the spool hole needs to ensure smooth movement of the valve to be fitted, the processing accuracy is managed very strictly. Therefore, the spool hole is finished by reamer. However, since the block is made of an aluminum alloy as described above, when the reamer penetrates the pilot hole, burrs are likely to occur at the peripheral edge of the spool hole. . If this burr enters the spool hole at the time of assembly, the spool hole and the valve may roll up and cause the valve to malfunction. In addition, when the spool hole and the valve come into contact with each other, a scratch is generated on the sliding surface, which is extremely difficult to correct, and the valve body and the valve may be discarded.

  Therefore, Patent Document 1 discloses that a burr generated at the opening peripheral edge of the hole when the first cutting blade penetrates the pilot hole is located behind the first cutting blade and outside the first cutting blade. There is a disclosure of a reamer that is removed by a cutting blade. By the way, it is well known to those skilled in the art that burrs are less likely to occur as the machining allowance (removal allowance) during reaming is smaller. However, in the reamer of Patent Document 1, the radial height of the second cutting edge is obviously larger than the radial height of the first cutting edge, as described in FIG. That is, in the reamer of Patent Document 1, since the machining allowance to be removed by the second cutting blade is large, there is still a possibility that burrs may be generated at the peripheral edge of the prepared hole due to the cutting by the second cutting blade.

As described above, Patent Document 1 discloses no cutting conditions in reamer processing (for example, the ratio of the radial height of the second cutting edge to the total machining allowance, the cutting feed amount per rotation of the reamer, etc.). It is not disclosed to the extent that can be easily implemented by those skilled in the art. Accordingly, there has been a demand for a reamer and a reamer processing method that can effectively suppress the generation of burrs.
JP-A-8-39350

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a reamer and a reamer processing method capable of effectively suppressing the generation of burrs.

  In order to solve the above-described problem, a reamer of the present invention includes a first cutting edge provided at a tip portion, a second cutting edge provided axially rearward and radially outward with respect to the first cutting edge, The second cutting edge is characterized in that the radial height is set to 60% or less of the radial height of the machining allowance of the pilot hole.

  In order to solve the above-described problem, a reamer processing method according to the present invention includes a first cutting edge provided at a tip portion, and a second cutting edge provided axially rearward and radially outward with respect to the first cutting edge. And reaming a pilot hole using a reamer having a cutting distance of 40% or more of the radial height of the pilot hole with the first cutting edge, The second cutting blade is used for cutting.

(Aspect of the Invention)
In the following, aspects of the invention that is recognized as being capable of being claimed in the present application (hereinafter referred to as claimable invention) will be exemplified, and each exemplified aspect will be described. Here, as in the claims, each aspect is divided into paragraphs, numbers are assigned to the respective paragraphs, and the descriptions of other paragraphs are cited as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combination of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiment, etc., and as long as the interpretation is followed, another aspect is added to the aspect of each section. Moreover, the aspect which deleted the component from the aspect of each term can also be one aspect of the claimable invention.
In the following items, each of items (1) to (6) corresponds to each of claims 1 to 6.

(1) A reamer having a first cutting edge provided at a tip portion and a second cutting edge provided axially rearward and radially outward with respect to the first cutting edge. The radial height is set to 60% or less of the radial height of the machining allowance of the pilot hole.
According to the reamer described in this section, the radial height of the second cutting edge is set to 60% or less of the radial height T0 (hereinafter referred to as the total machining allowance T0) of the total machining allowance of the pilot hole. That is, the radial height T1 of the machining allowance cut by the first cutting edge (hereinafter referred to as machining allowance T1) is 40% or more of the total machining allowance T0, that is, the radial direction of the remaining machining allowance cut by the second cutting edge. The height T2 (hereinafter referred to as the allowance T2) is 60% or less of the total allowance T0 (T0 = T1 + T2). In other words, the final machining allowance T2 cut by the second cutting edge can be 60% or less of the total machining allowance T0 (0.6 * T0 ≧ T2). As described above, it is well known that burrs can be suppressed as the machining allowance is small. Therefore, according to the reamer described in this section, the generation of burrs can be effectively suppressed.

(2) The reamer according to (1), wherein the second cutting edge has a biting angle set to 45 °, and the first cutting edge has a biting angle set between 60 ° and 80 °.
According to the reamer described in this section, the first cutting edge with a relatively large chamfer angle is used to cut at the machining allowance T1 while effectively suppressing runout, and the remaining machining allowance T2 is It is cut by the second cutting edge, which has a high 45 ° burr suppression effect. Therefore, even when the first cutting edge penetrates the pilot hole and a burr is generated at the opening peripheral edge of the hole, the burr can be surely removed by the second cutting edge.

(3) The reamer according to (1) or (2), wherein the second cutting edge is continuously formed at an axial rear end portion of the first cutting edge.
In the reamer of the prior art, the second cutting edge is not continuous with the first cutting edge, and is provided at an interval rearward in the axial direction from the axial rear end of the first cutting edge. Tool feed between the time when the 1st cutting edge penetrates the pilot hole and the time when the 2nd cutting edge reaches the opening of the pilot hole was useless, causing man-hours to increase. According to the reamer, since the first cutting edge penetrates the pilot hole and the second cutting edge reaches the opening of the pilot hole, there is no waste of tool feeding, and productivity can be improved.
In the aspect of this section, the first cutting edge and the second cutting edge can be disposed on the same chip of the chip reamer.

(4) Reaming the pilot hole using a reamer having a first cutting edge provided at the tip end and a second cutting edge provided axially rearward and radially outward with respect to the first cutting edge. A reaming method in which the first cutting edge is used to cut 40% or more of the radial height in the cutting allowance of the prepared hole while the remaining cutting allowance is cut using the second cutting edge.
According to the reaming method of this section, the first cutting edge is used to cut the pilot hole with a cutting allowance T1 of 40% or more of the total cutting allowance T0, while the remaining cutting allowance T2 is cut using the second cutting edge. In other words, while cutting the prepared hole with the first cutting edge at the cutting allowance T1, the remaining cutting allowance T2 of 60% or less of the total cutting allowance T0 is cut with the second cutting edge. Therefore, according to the reaming method of this section, the machining allowance T2 cut by the second cutting edge can be reduced to 60% or less of the total machining allowance T0. As described above, it is well known that the generation of burrs is suppressed as the machining allowance is small. Therefore, the generation of burrs can be effectively suppressed.

(5) The remaining cutting allowance is cut with the second cutting edge with a chamfering angle of 45 ° while the pilot hole is cut with the first cutting edge with a chamfering angle of 60 ° to 80 ° (1). Reaming method.
According to the reaming method described in this section, the first cutting edge with a relatively large chamfer angle is used to cut at the machining allowance T1 while effectively suppressing the runout, and the remaining machining allowance T2 is suppressed to burr. Cutting with a second cutting edge having a high biting angle of 45 °. Therefore, even when a burr is generated at the opening peripheral edge of the hole when the first cutting edge passes through the pilot hole, the burr can be reliably removed by the second cutting edge.

(6) The reaming method according to (4) or (5), wherein an axial feed amount per rotation of the reamer is set to be equal to or less than half of an axial length of the second cutting blade.
According to the reaming method described in this section, the remaining machining allowance T2 when the first cutting edge penetrates the pilot hole can be cut by rotating the reamer at least twice. Therefore, the burr generated at the opening peripheral edge of the pilot hole when the first cutting blade penetrates the pilot hole can be reliably removed by at least two rotations of the second cutting blade.

(7) The reaming method according to any one of (4) to (6), wherein the remaining machining allowance of the first cutting edge is cut by a second cutting edge continuous to the axial rear end portion of the first cutting edge.
In the prior art reamer, the second cutting edge is not continuous with the first cutting edge. For this reason, in the reaming process of the prior art, after cutting with the first cutting edge, the remaining machining allowance T2 is provided at a distance from the rear end in the axial direction of the first cutting edge to the rear in the axial direction. It was cut by a blade. Therefore, in the reaming process of the prior art, the tool feed from when the first cutting edge passes through the pilot hole until the second cutting edge reaches the opening of the pilot hole is useless, and the number of man-hours increases. However, according to the reaming method in this section, the first cutting blade penetrates the pilot hole and at the same time the second cutting blade reaches the opening of the pilot hole. Can be improved.

  It is possible to provide a reamer and a reamer processing method capable of effectively suppressing the generation of burrs.

An embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the reamer 1 of the present embodiment is provided with a single straight groove 3 extending in the axial direction (left-right direction in FIG. 1) on the outer peripheral portion of a cylindrical blade portion 2. . In the reamer 1, a cutting edge tip 5 is attached to a concave tip attaching portion 4 formed at the tip of the straight groove 3. The cutting edge tip 5 can be made of cemented carbide tool steel, diamond sintered body, or the like.

  The cutting edge tip 5 is formed with a first cutting edge 6 whose chamfering angle λ1 is set between 60 ° and 85 ° (70 ° in this embodiment) at the tip thereof. In addition, the cutting edge tip 5 has a second cutting edge 7 that is continuous with the rear end portion 6 a (axial rear end portion) of the first cutting edge 6. The second cutting edge 7 has a biting angle λ2 of 45 °, and is axially rearward (rightward in FIG. 1) and radially outward (lower in FIG. 1) with respect to the first cutting edge 6. To position. The first cutting edge 6 has a cutting edge height H1 (radial height) of the remaining cutting allowance T2, that is, the cutting allowance T2 removed by the second cutting edge 7 after cutting by the first cutting edge 6 is a pilot hole. It is set to be 60% or less of the total allowance T0 of 8 (0.6 * T0 ≧ T2). The second cutting edge 7 has a cutting edge height H2 that is naturally equal to the remaining machining allowance T2 after cutting by the first cutting edge 6 (0.6 * T0 ≧ H2 = T2).

Next, the operation of this embodiment will be described. Here, the case where the spool hole of the valve body made of aluminum alloy in which the machining of the pilot hole 8 by the drill has been completed is reamed by the reamer 1 of the present embodiment will be described.
The cutting conditions are as shown below.
Material of cutting edge tip 5: Chamfer angle (λ1) of first sintered cutting edge 6 of diamond sintered body: 70 °
Chamfer angle of second cutting edge 7 (λ2): 45 °
Radial height of the second cutting edge 7 (H2): 0.15 mm (60% of T0)
Total allowance for pilot hole 8 of spool hole (T0): 0.25 mm
The machining allowance (T1) removed by the first cutting edge 6: 0.10 mm (40% of T0)
The machining allowance removed by the second cutting edge 7 (T2): 0.15 mm (T2 = H2, 60% of T0)
Cutting feed rate (f): 0.07 mm / rev (less than half of T2)

  Under the above conditions, as shown in FIG. 3, the first cutting edge 6 having a cutting allowance T1 (0.1 mm) of 40% of the total machining allowance T0 (0.25 mm) and a chamfer angle λ1 of 70 ° is used as a pilot hole 8. The remaining machining allowance T2 (0.15 mm) is cut by the second cutting edge 7 having a chamfer angle λ2 of 45 ° continuous to the rear end portion 6a of the first cutting edge 6. As shown in FIG. 4, when the first cutting edge 6 passes through the pilot hole 8, the axial length L0 of the remaining machining allowance T2 is the axial length L2 of the second cutting edge 7, that is, Since the biting angle λ2 of the second cutting edge 7 is 45 °, a distance equal to the radial height H2 (0.15 mm) remains (L2 = H2).

When the first cutting edge 6 passes through the pilot hole 8, the remaining machining allowance T2 whose axial length is L0 is such that the cutting feed amount f (0.07 mm) per rotation of the reamer 1 is that of the second cutting edge 7. Since it is set to be less than half of the axial length L2 (0.15 mm), as shown in FIG. 5, the reamer 1 is cut with at least two rotations (three rotations in this embodiment). In other words, while taking the reamer 1 by f (0.07 mm) per rotation and gradually decreasing the radial height of the machining allowance T2 in the vicinity of the opening of the pilot hole 8, the machining allowance T2 in the immediate vicinity of the opening of the pilot hole 8 is decreased. To cut.
In addition, as a result of reaming the spool hole of the valve body made of aluminum alloy using the reamer 1 of the present embodiment, no burr was generated even when 1000 valve bodies were processed.

This embodiment has the following effects.
According to this embodiment, the first cutting edge 6 cuts 40% or more of the total machining allowance T0 of the pilot hole 8, while the remaining machining allowance T2, that is, the machining allowance of 60% or less of the total machining allowance T0 of the pilot hole 8. T2 is cut by the second cutting edge 7. Accordingly, it is well known that the smaller the machining allowance is, the higher the burr suppression effect is. Therefore, according to this embodiment, the machining allowance T2 of the second cutting edge 7 is set relatively large with respect to the total machining allowance T0. As compared with, generation of burrs can be effectively suppressed.
According to this embodiment, the biting angle λ1 of the first cutting edge 6 is set between 60 ° and 85 ° (70 ° in this embodiment), and the biting angle λ2 of the second cutting edge 7 is 45 °. Set to. Therefore, according to the present embodiment, the first cutting edge 6 having a relatively large biting angle λ1 performs the first cutting with a machining allowance T1 of 40% or more of the total machining allowance T0 while effectively suppressing the runout. The remaining machining allowance T2, that is, machining allowance T2 of 60% or less of the total machining allowance T0 is cut by the second cutting edge 7 having a chamfering angle λ2 of 45 °, which has a high burr suppressing effect. Thereby, even if the first cutting edge 6 passes through the pilot hole 8 and a burr is generated at the opening peripheral edge of the pilot hole 8, the burr can be reliably removed by the second cutting edge 7. .
According to this embodiment, since the second cutting edge 7 is made continuous with the rear end portion 6a of the first cutting edge 6, the first cutting edge 6 penetrates the pilot hole 8 and at the same time the second cutting edge 7 The opening of the hole 8 is reached. Therefore, there is no waste of tool feeding as in the prior art, and productivity can be improved.
In the present embodiment, the cutting feed amount f per rotation of the reamer 1 is set to a setting equal to or less than half of the axial length L2 of the second cutting edge 7. Here, since the axial length L2 of the second cutting edge 7 is equal to the axial length L0 of the remaining machining allowance T2 when the first cutting edge 6 penetrates the pilot hole 8, the first cutting edge 6 The remaining machining allowance T2 at the time of passing through the pilot hole 8 is cut by at least two rotations of the reamer 1. In other words, according to the present embodiment, the radial height of the machining allowance T2 in the immediate vicinity of the opening of the pilot hole 8 is decreased stepwise by sending the reamer 1 by f per rotation, while the proximity of the opening of the pilot hole 8 is approached. Cutting Toro allowance T2. Therefore, even if the first cutting edge 6 passes through the pilot hole 8 and burrs are generated at the opening peripheral edge of the pilot hole 8, the burrs can be reliably removed by the second cutting edge 7.

In addition, embodiment is not limited above, For example, you may comprise as follows.
In the present embodiment, the reamer 1 is configured by providing one straight groove 3 in the blade portion 2 and attaching the cutting blade tip 5 to the tip mounting portion 4 of the straight groove 3. The reamer 1 may be configured by providing two straight grooves 3 having an angle phase of 180 ° and attaching the cutting edge tips 5 to the tip attaching portions 4 of the respective straight grooves 3.
In the present embodiment, the reamer 1 having the chip-type cutting blades 6 and 7 has been described. However, the reamer 1 is formed by forming the first cutting blade 6 and the second cutting blade 7 at the tip of the groove formed in the blade portion 2. May be formed.
In the present embodiment, the second cutting edge 7 is connected to the rear end portion 6a of the first cutting edge 6. However, other conditions (each of the biting angles λ1 and λ2 of the cutting edges 6 and 7, If the ratio of the machining allowance T2 cut by the blade 7 to the total machining allowance T0 is the same, an axial interval may be provided between the first cutting edge 6 and the second cutting edge 7 as necessary. Good. However, of course, the distance between the first cutting edge 6 and the second cutting edge 7 is preferably as small as possible.

It is a front view of the front-end | tip part of the blade part of the reamer of this embodiment. It is a top view of the reamer of FIG. It is explanatory drawing of this embodiment, Comprising: It is the figure which showed the machining allowance in the cross section before a 1st cutting blade penetrates a pilot hole. In FIG. 3, it is a figure which shows the state at the time of a 1st cutting blade penetrating a pilot hole. It is a figure which shows that machining allowance is cut in steps by the feed f from the state of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reamer, 5 Cutting edge tip, 6 1st cutting edge, 6a Rear end part (axial direction rear end part of 1st cutting edge), 7 2nd cutting edge, 8 Pilot hole

Claims (6)

A reamer having a first cutting edge provided at the tip, and a second cutting edge provided axially rearward and radially outward with respect to the first cutting edge,
The second cutting edge has a radial height set to 60% or less of a radial height of a machining allowance for a pilot hole. The chamfer angle of the second cutting edge is set to 45 °, and the chamfer angle of the first cutting edge is set between 60 ° and 85 °. Reamer. 3. The reamer according to claim 1, wherein the second cutting edge is continuously formed at an axial rear end portion of the first cutting edge. A method of reaming a prepared hole using a reamer having a first cutting edge provided at a tip portion and a second cutting edge provided at an axially rearward side and a radially outer side with respect to the first cutting edge Because
A reaming method comprising cutting the remaining machining allowance with the second cutting edge while cutting 40% or more of the radial clearance height of the prepared hole with the first cutting edge. The remaining cutting allowance is cut by the second cutting edge having a chamfering angle of 45 ° while the pilot hole is cut by the first cutting edge having a chamfering angle of 60 ° to 85 °. The reamer processing method according to claim 4. The reaming method according to claim 4 or 5, wherein an axial feed amount per rotation of the reamer is set to be equal to or less than half of an axial length of the second cutting blade.

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