JPH03270816A - Abrasive grain reamer - Google Patents

Abstract

PURPOSE:To conduct an efficient grinding processing, by providing a biting portion and a finishing portion at an abrasive grain reamer which is used for the grinding of the bore of the cylinder block of an automobile engine, and increasing the quantity of processing without making the biting portion long. CONSTITUTION:At this abrasive grain reamer, the twists of edge grooves 6a at a biting portion 1a are larger than those of edge grooves 6b at a finishing portion 1b, and also grains at the cutting edges 5a of the biting portion 1a are larger than those at the cutting edges 5b of the finishing portion 1b. And in this instance, cutting edges 5a, 5b are continuous to each other, and also edge grooves 6a, 6b are connected to each other. The grinding processing quantity of the biting portion 1a can be rapidly increased without changing the outer diameter size of the abrasive grain reamer by constituting the abrasive grain reamer as above.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an abrasive reamer used for polishing bores, etc. of cylinder blocks of automobile engines.

(Prior Art) Conventionally, an abrasive grinder used for polishing the inner circumferential surface of a bore of a cylinder block in an automobile engine has a configuration as shown in FIG. That is, this abrasive reamer 11 consists of a tapered chamfered part 11a at the tip and a finished part flb formed in a continuous manner behind this chamfered part 11a, and has abrasive grains attached thereto. Band-shaped cutting blade 1
A blade groove 13 formed between the two has a predetermined helix angle with respect to the axis.

By the way, in such a conventional abrasive reamer 11, the blade groove 13 between the cutting blades 12 is narrow because processing is performed using abrasive grains, and in order to increase the amount of processing (machining allowance), It was necessary to increase the length L of the portion 11a.

However, if the hole whose inner circumferential surface is to be polished is a through hole, or if there is a dimensional margin at the bottom of the hole, it is possible to increase the length of the chamfered portion 11a; Even if it is a through hole, such as a bore, if there is a main bearing section below the through hole and there is no dimensional margin, it is impossible to lengthen the chamfered portion.

Therefore, conventionally, it was necessary to improve the accuracy of the polling process, which is the previous process, or to divide the process using an abrasive reamer into two processes.

(Objective of the Invention) Therefore, an object of the present invention is to provide an abrasive reamer that can increase the processing amount without increasing the length of the chamfered portion and perform efficient polishing.

(Structure of the Invention) The present invention is characterized in that the blade groove of the chamfered part has a larger helix angle than the blade groove of the finished part, and the abrasive grains on the cutting edge of the chamfered part are in the cutting edge of the finished part. It is characterized by having a particle size larger than that of abrasive grains.

(Effects of the Invention) In the abrasive reamer according to the present invention, the helix angle of the blade groove in the chamfered part is made larger than that in the finished part, and the grain size of the abrasive grains in the cutting edge of the chamfered part is made larger than that of the abrasive grains in the finished part. Since it is made larger, the amount of polishing at the chamfered portion can be increased without changing the length of the entire cutting edge. Therefore, the load on the finished part is reduced, and a hole with high dimensional accuracy and a smooth inner circumferential surface can be machined by -degree polishing.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1(A) is a partially sectional front view showing one embodiment of an abrasive grain reamer according to the present invention, and FIG. 1(B) is a bottom view thereof. 1 is an abrasive reamer, and this abrasive reamer 1 is composed of a chamfered part 1a and a finished part 1b formed integrally with the shank 2 behind the chamfered part 1a. Biting part 1
a and the finished portion 1b are fixed to each other in the axial direction with a bolt 3 in a centered relationship, and a rotation stopper pin 4
They are locked in the circumferential direction by , so that they can rotate together.

The cutting groove 6b of the finishing part 1b has a helix angle of about 15 degrees with respect to the axis, and abrasive grains having a grain size of about 0.15 mm are adhered in a band shape to form a cutting edge 5b.

are doing.

On the other hand, the blade groove 6a of the chamfered portion 1a is 45 to 7 mm with respect to the axis.
Abrasive grains having a helix angle of 0° and a grain size of approximately 0.4 mm are deposited in a band shape to form the cutting edge 5a. That is, the blade groove 6a of the chamfered portion 1a is the finished portion 1b.
has a larger helix angle than the blade groove 6b, and the abrasive grains on the cutting edge 5a of the chamfered portion 1a are larger than the cutting edge 5b of the finished portion 1b.
It is characterized by having a particle size larger than that of the abrasive grains. In this case, the cutting edges 5a, 5b are continuous with each other, and the blade grooves 6a, 6b are also in communication with each other.

By configuring the abrasive reamer in this manner, the amount of polishing of the chamfered portion 1a can be dramatically increased without changing the outer diameter of the abrasive reamer.

[Brief explanation of drawings]

FIG. 1(A) is a partially sectional front view showing one embodiment of the present invention, FIG. 1(B) is a bottom view thereof, and FIG. 2 is a front view showing a conventional abrasive reamer. 1... Abrasive reamer 1a... Chamfered part 1b.
... Finished parts 6a, 6b...Blade grooves 5a, 5b...Cutting edge

Claims (1)

[Scope of Claims] A finished part in which a cutting edge formed between the cutting edges to which abrasive grains are adhered has a predetermined helix angle with respect to the axis, and a finished part that is connected to the tip side of this finished part is formed. In an abrasive reamer having a chamfered part, the blade groove of the chamfered part has a larger helix angle than the blade groove of the finished part, and the abrasive grains on the cutting edge of the chamfered part are arranged in the finishing part. An abrasive reamer characterized in that the abrasive grain size is larger than that of the abrasive grains in the cutting edge of the part.