JPS60238203A - Cemented carbide shaft with hollow hole and manufacturing method - Google Patents

Abstract

PURPOSE:To make it possible to readily manufacture a cemented carbide shaft with hollow hole at a low cost by providing the hollow hole of which inner cylindrical surface becomes the surface preparatively formed between the notch groove provided at the outer cylindrical surface of the body and the lid fitted in the opening portion of the notch groove. CONSTITUTION:A cemented carbide shaft 10 consists of the body 11 of which outer cylindrical surface is provided with a notch groove and the lid 12 fitted in the opening portion of the notch groove. Then, after the faces 12b and 12b' of this lid 12 and the faces 11b and 11b' of the notch groove are butted respectively with brazing materials between them, and when the brazing materials are melted by heat to fit them tightly, a half completed shaft is obtained. After then, when the excess metal of the lid 12 protruded over an imaginative outer cylindrical surface 14 of the body 11 is ground until a cylindrical surface is formed, the cemented carbide shaft 10 having a hollow hole 13 of which inner cylindrical surface consists of the parts of the faces 11b and 11b' and the face of a groove 12a is completed. As a result, even the shaft having a long hollow hole can be readily manufactured without spending a lot of time and raising the production cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention is applicable to cutting tools such as line bars and boring bars used for cutting camshaft holes and crankshaft holes in engine cylinders. This invention relates to a carbide shaft with a hollow hole suitable for use in, and a method for manufacturing the same.

(2) Prior Art As shown in FIGS. 1 and 2, a line bar with a cutting tool such as a cutting tool 2 installed in the middle of the shaft body 1; as shown in FIG. For deep drilling nitrile, etc. with a boring bar equipped with the blade 4 or a gun drill, etc.
Providing a hollow hole in the shaft or shank for supplying a coolant such as cutting oil or air is highly desirable in terms of increasing the life of the cutting edge and the ability to dispose of chips.

By the way, in the conventional long liner having a hollow hole, a copper material is used as the material of the shaft body 1, and a hollow hole 5 (see FIG. 2) is bored in the shaft core. In the case of the boring bar and deep-hole nitrile shown in Fig. 3, only the cutting edge and head are made of cemented carbide, etc., and the shank part 3 to which the brazing is connected is made of steel and has a hollow hole in its axis. In most cases,

(3) Problems to be solved by the invention However, cutting tools that use a steel shaft in the part that receives the cutting force have a long length relative to the shaft diameter because the Young's modulus of steel is low compared to other tool materials. When the width dimension increases, the strength tends to be insufficient, which causes vibration during machining, so-called chatter, which has the drawback of reducing the surface roughness of the machined surface, the roundness of the hole, and the dimensional accuracy of the hole.

Despite these drawbacks, steel is traditionally used as a material for long shafts with hollow holes, whereas steel can relatively easily form long holes by drilling. Although it is possible to drill holes in hard cemented carbide, it takes a long time to process, which is disadvantageous in terms of cost.In the case of cemented carbide shafts, the inner plug must be passed through during press molding of powder material. It is possible to create a hollow hole by removing the stopper later, but making a long hole using this method is nearly impossible with the current technology.

(4) Means for Solving the Problems The present invention provides a carbide shaft that allows easy machining of hollow holes even in long materials, and a method for manufacturing the same. A hard shaft consists of a main body and a lid attached to the shaft, and the hollow hole has a notched groove extending lengthwise around the outer circumference of the main body, and both sides are airtightly fitted into the opening of this notched groove. It is characterized by being provided between the lid and the lid that is joined to the lid.

The method for the second purpose consists of attaching the lid, which has a space around the outer periphery of the main body, to the opening of the notched groove by brazing only both sides of the lid in an airtight manner.

In this way, if a hollow hole is provided between the main body provided with the notched groove and the lid joined to the opening of the groove, this hole can be formed by pressing or stamping in advance, so it is possible to This makes it easier to attach long holes to the holes.

(5) Example Examples of the present invention are listed below.

As shown in FIGS. 4 to 6, the exemplary carbide shaft 10 is
Main body 11 provided with notch grooves 11a extending in the same length direction on the outer periphery
and a lid 12 that is joined to the opening of the notch groove.

The lid 12 has a groove 12a that creates a space between the notched groove constituent surfaces 1 l b , 11 b / and the intersection angle of the extension line of the inner corner of the square timber is the intersection angle of the notched groove surfaces 11 b , 11 b / . Match.

Surfaces 12b and 12b' of this lid 12 and surface 1 of the notch groove
1b and 11b/ are butted together with a solder material inserted between them, and then the solder material is heated and melted to join them airtightly to obtain the semi-finished shaft shown in FIG. After that, when the excess thickness of the lid 12 that protrudes from the outer peripheral surface of the main body 11 is ground to make the lid and the outer peripheral surface of the main body continuous, a part of the surfaces 11b and llb' and the groove 12a
The carbide shaft 10 with the hollow hole 13 whose inner surface is the inner peripheral surface is completed.

Note that as the material for the main body 11 and the lid 12, ceramic or the like can be used in addition to cemented carbide. This ceramic etc. is -
It is best to metallize the joint surfaces beforehand before brazing the main body and lid.

When brazing a long, long lid, there is a risk that the adhesion of the joint surfaces will deteriorate due to thermal distortion of the lid. This can be solved by joining. For example, if the lid is divided into three parts along the chain lines in FIGS. 5 and 6, it becomes smaller.

Furthermore, although the cross-sectional shape of the hollow hole 13 is rectangular, triangular, or elliptical, it has excellent workability, but other shapes are also possible.

The carbide shaft 10 may also be a square shaft in addition to the circular shaft shown, and the outer periphery of the lid may be ground as necessary. However, notch groove 1
The cross-sectional shape of 0a rotates and expands outward as shown in the figure7.
It is preferable to use a letter shape or a shape similar to it. This is because the positioning function when joining the lid can be obtained using the method that is easiest to process.

In addition, when the hollow hole 13 is provided at a position offset from the axis of the main body 11, the rigidity of the shaft is less reduced, and the following advantages are also produced.

That is, if the hollow hole 5 of a line bar or the like is located at the axis as shown in FIG. 2, the design may force the installation hole of the cutting tool 2 or its accessories to overlap with the hollow hole, and in this case, As the distance from the inlet hole increases, the supply pressure of the coolant decreases significantly, the supporting area of the blade decreases, and the clamping force of the blade decreases.
As shown in FIG. 7, if the hollow hole 13 is located off the axis, the cutting tool 2 or the like can be installed while avoiding this hole, thereby improving the performance and reliability of the tool.

(6) Effects As explained above, the carbide shaft with a hollow hole and the manufacturing method thereof of the present invention have a preformed surface between the notch groove provided on the outer periphery of the main body and the lid joined to the opening thereof. Since the hollow hole that forms the circumferential surface is provided, even a shaft with a long hollow hole can be easily obtained without spending a long time and without increasing cost.

[Brief explanation of drawings]

Figure 1 is a front view of the line /<- using a shaft with a hollow hole, Figure 2 is a cross-sectional view along the low ■ line, and Figure 3 is a front view of a boring bar with a shank with a hollow hole. ,
4 to 6 are perspective views showing a carbide shaft with a hollow hole according to the present invention and a method for manufacturing the same, and FIG. 7 is a sectional view showing an example of a cutting tool using the shaft.

Claims (6)

[Claims] (1) In a carbide shaft with a hollow hole extending in the length direction inside, the shaft is composed of a main body and a lid attached to the main body, and the hollow hole is provided with a notch extending in the longitudinal direction on the outer periphery of the main body. A carbide shaft with a hollow hole, characterized in that the groove is provided between the groove and the lid whose both sides are hermetically joined to the opening of the notched groove. (2) A carbide shaft with a hollow hole according to claim (1), wherein the hollow hole is provided at a position offset from the axis of the main body. (3) The hollow holed superstructure according to claim 11 or (2), characterized in that the cross-sectional shape of the notch groove is a 7-shape that expands toward the outer periphery or an approximate shape thereof. Hard shaft. (4) A notched groove extending in the length direction is provided on the outer periphery of the main body, and the lid is made airtight with only both sides of the lid having a space between the both sides and some constituent surfaces of this groove in areas other than the outer circumferential surface. A method of manufacturing a carbide shaft with a hollow hole, which comprises brazing the shaft into the shaft and installing it into the opening of the notched groove. (5) After the lid is joined, excess thickness on the outer periphery of the lid is ground to match the outer peripheral surfaces of the lid and the main body, as set forth in claim (4). Hard shaft manufacturing method. (6) A carbide shaft with a hollow hole according to claim 4 or 5, wherein the lid is divided into a plurality of parts in the length direction and brazed to the main body. Production method.