JPH0529628U - Reamer - Google Patents

Abstract

(57) [Summary] [Purpose] To make the structure that can improve the life of the tool. [Structure] The edge contact portion 5a of the round land blade 5 is provided so as to be retracted by a dimension t from the blade edge corrosion portion 4b of the cutting blade 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a reamer used for finishing a cylinder head valve guide hole of an automobile, for example.

[0002]

[Prior Art]

 For the cylinder head valve guide hole, etc., a small diameter hole is first made with a drill, and then the inner surface of the hole is cut with a reamer to be finely finished.

FIG. 3 shows a structure of a general reamer 1, and the blade portion 2 and the shank 3 are roughly formed into a single rod shape. Further, as shown in FIG. 4 as an enlarged vertical side view of the blade portion 2 taken along the line AA in FIG. 3, a plurality of blades are provided on the peripheral surface at substantially equal intervals. The number of blades is freely selected, but in this embodiment, six blades are provided. Of these, four blades are cutting blades 4 and the remaining two blades are formed as round land blades 5. These two round land blades 5 are provided every time the two cutting blades 4 are crossed. .

More specifically, the cutting edge 4 is formed with the cutting edge clearance angle θ1 set to about 20 degrees and the cutting edge 4a being sharpened. On the other hand, the round land blade 5 is formed without a clearance angle of the cutting edge, and the blade tip contact portion 5a is formed so as to substantially match the curvature of the peripheral surface. Further, as shown in FIG. 5, the cutting edge biting portion 4b of the cutting blade 4 and the cutting edge abutting portion 5a of the round land blade 5 are formed at positions of substantially the same size T from the tip.

6 and 7 schematically show the operating state of the reamer 1 thus formed. That is, when this reamer 1 is inserted into the hole for further cutting and cutting up the inside of the hole made by a drill or the like, the cutting edge 4 of the cutting blade 4 causes the inner edge 6 of the hole 6 (see FIG. 6). Then, the cutting edge 4 is used for cutting. FIG. 6 shows this state, and the reference numeral 7 a is a cutting waste cut by the cutting blade 4. After cutting with the cutting edge 4, as shown in FIG. 7, the edge contact portion 5a of the round land blade 5 comes into contact with the inner surface 6, and then the entire edge of the round land blade 5 comes into pressure contact with the inner surface 6. It is crushed and crushed, that is, burnished, and then surface-finished.

[0006]

[Problems to be solved by the device]

 As described above, in the reamer 1, after the cutting blade 4 finish-cuts, the finish-cut surface is further subjected to burnishing by the pressure contact of the round land blade 5 for final finishing. However, the cutting edge 4 of the cutting blade 4 and the cutting edge contact portion 5a of the round land blade 5 are formed to be substantially equal to each other with the distance T from the tip of the reamer 1, and therefore the round land blade 5 is actually formed. The blade edge contact portion 5a is also used as a cutting blade. FIG. 7 shows the state, and the portion indicated by reference numeral 7b is a cut waste. For this reason, the frictional load on the round land blade 5 is increased, and the round land blade 5 is easily broken. This is because, for example, when finishing a cylinder head valve guide hole with a diameter of about 5 mm (mm), one reamer 1 can process only about 360 holes, and the tool life is short. There was a problem to say.

The present invention has been made in view of the above problems, and an object thereof is to provide a reamer having a structure capable of improving the life of a tool.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, a reamer according to the present invention is provided with a plurality of cutting blades and a round land blade on the same blade portion, and the cutting edge contact portion of the round land blade is a cutting edge of the cutting blade. It is provided so as to be set back from the feeding portion.

[0009]

[Action]

 According to this configuration, since the blade landing portion of the round land blade is set back from the cutting edge portion of the cutting blade, the round land blade can be cut only by burnishing after the cutting blade scrapes. It is rarely used. Therefore, the total friction load applied to the round land blade is reduced.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a main structure of a reamer according to an embodiment of the present invention, and shows a portion corresponding to the blade portion 2 of the reamer 1 shown in FIG. Further, the reamer 11 in this embodiment comprises a blade portion 2 and a shank (not shown), and its basic structure is the same as that of the conventional reamer 1 shown in FIGS. 3 to 7. Further, a plurality of (six in the present embodiment) blades are provided on the peripheral surface of the blade portion 2 at substantially equal intervals, of which four blades are cutting blades 4 and the remaining two blades are circular. It is also the same as that it is formed as a land blade 5, and the two round land blades 5 are provided every time the two cutting blades 4 are crossed. Therefore, parts corresponding to those of the conventional reamer 1 shown in FIGS. 3 to 7 are designated by the same reference numerals, and duplicated description will be omitted.

The major difference between the conventional reamer 1 shown in FIGS. 3 to 7 and the reamer 11 of the present invention shown in FIG. 1 is that the edge contact portion 5 a of the round land blade 5 is replaced by the blade edge of the cutting edge 4. It is provided so as to be retracted from the feeding portion 4b. That is, as shown in FIG. 2, when the dimension from the tip of the reamer 11 to the cutting edge corroded portion 4b of the cutting blade 4 is T, the dimension from the tip of the reamer 11 to the blade tip contact portion 5a of the round land blade 5 is ( T + t). Note that the angle θ in FIG. 2 is an inclination formed as a clearance from the tip of the reamer 11 to the cutting edge 4b of the cutting blade 4 and from the tip of the reamer 11 to the tip contact portion 5a. It is the same as the cutting blade 4 and the round land blade 5, and is set to about 45 degrees.

Therefore, in the reamer 11 formed in this manner, when the reamer 11 is inserted into the hole for further cutting and finishing the inside of the hole formed by a drill or the like, the cutting edge contact portion 5a of the round land blade 5 is cut. Since the blade 4 is recessed from the blade-cored portion 4b by the dimension t, the blade-cored portion 4b is only pressed and burnished after the inner surface of the hole is scraped off. Therefore, the overall frictional load applied to the round land blade 5 is reduced, the breakage of the round land blade 5 is reduced, and the life of the tool can be improved.

According to an experiment conducted by the applicant of the present application, when finishing machining the cylinder head valve guide hole having a diameter of about 5 mm, the edge contact portion of the round land blade 5 with respect to the tooth corroded portion 4b of the cutting blade 4 is finished. With the structure in which 5a is retracted by about 0.2 mm, even if about 900 holes are machined with one reamer 11, it can be used without breaking, and the conventional reamer 1 has about 360 holes. On the other hand, the life could be extended by about 3 times.

[0014]

[Effect of the device]

 As described above, in the reamer according to the present invention, since the blade landing portion of the round land blade is set back from the cutting edge portion of the cutting blade, the round land blade burnishes after cutting off the cutting blade. It is rarely used for cutting alone. As a result, the overall frictional load applied to the round land blade is reduced, breakage can be prevented, and the service life can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing the structure of a main part of a reamer according to the present invention.

FIG. 2 is a diagram for explaining a relationship between a cutting edge biting portion of a cutting blade and a cutting edge contact portion of a round land blade in the same reamer shown in FIG.

FIG. 3 is a schematic overall configuration diagram of a general reamer.

4 is an enlarged vertical side view taken along the line AA of FIG.

FIG. 5 is a perspective view of a main part of a conventional reamer.

FIG. 6 is a diagram for explaining the operation of the cutting blade in the conventional reamer.

FIG. 7 is an operation explanatory view of a round land blade in a conventional reamer.

[Explanation of symbols]

 1 Reamer 2 Blade 3 Shank 4 Cutting blade 4b Cutting edge part 5 Round land blade 5a Cutting edge contact 11 Reamer

Claims (1)

[Scope of utility model registration request] 1. A reamer in which a plurality of cutting blades and a round land blade are provided on the same blade portion, wherein a cutting edge contact portion of the round land blade is provided with a retreat from a cutting edge portion of the cutting blade. Reamer characterized by that.