JP2000233321A - Throw-away type gear hob - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a throw-away type gear hob, in which the number of edges is increased, to extend the life of tips, suppress cutting vibration, and improve the quality of finished surfaces and the machining accuracy. SOLUTION: A throw-away type hob 1 or a multi-turn hob with module m5 to m20, is composed of a combination of end part one turn roughing gear hobs 2 and intermediate part one turn roughing gear hobs 3. For cutting edge tips 10, right cutting edge tips and left cutting edge tips are mounted equally spaced along tooth traces in a zigzag pattern in the shape of vertical inserts, and the cutting edge tips are respectively arranged on parallel lines in parallel with the rotary shaft in a state where they are assembled into the multi-turn hob. With respect to the adjacent tooth traces, the cutting edge tips are arranged so that they are respectively on imaginary lead L lines the lead angle β of which is 15 deg. to 30 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away type hob constructed by assembling a single-turn hob into a multi-turn hob.

[0002]

2. Description of the Related Art It is known to assemble a single-turn hob into a multi-turn hob, which is disclosed, for example, in Japanese Utility Model Laid-Open No. 50621/1986. On the other hand, Japanese Patent Application Laid-Open No. 9-1178 discloses a hob with a technical problem of high precision and high efficiency of gear cutting.
There is one disclosed in Japanese Patent Publication No. 24. The hob body is an integral multi-turn hob, on which the right-edge tips and the left-edge tips arranged in a staggered manner are screwed and fixed in an upright insert state. The right edge tip and the left edge tip are alternately arranged on the parallel line of the rotation axis so that the left and right balance of the cutting force is maintained. In order to realize this, the relationship of the chip arrangement between adjacent tooth traces is numerically limited.

[0003]

An object of the present invention is to realize a throw-away type hob having a large number of blades. At first glance, the arrangement of the cutting edge chips as described above seems to balance the cutting force, but since the gear material as the workpiece is disk-shaped and cuts its outer peripheral surface, There are not many moments in which the alternately arranged right edge tip and left edge tip are simultaneously involved in cutting and the balance is maintained.

[0004] Further, if the number of blades is further increased in the hob having the above-described configuration, it is impossible to machine a screw hole for mounting a cutting blade tip due to interference with a main body portion during manufacturing. In addition, there is a problem in that the chip mounting seat must be formed by special machining such as electric discharge machining instead of cutting, resulting in an increase in cost.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above problem. A rectangular flat plate-like cutting blade tip is detachably mounted on a vertical insert body in a disk-shaped tool body. A winding hob is configured, and a module m5 configured as a multiple winding hob by combining such a single winding hob is provided.
In the throw-away type hob of m20, the cutting blade tip is mounted such that the right blade tip and the left blade tip are arranged in a staggered manner along the tooth trace, and each cutting blade tip is
In the state of being assembled in the multi-turn hob, they are arranged in parallel on the rotation axis and in parallel with each other, and at the same time, as if on a virtual lead wire having a lead angle β of 15 ° to 30 ° in relation to adjacent tooth traces. It is characterized by being arranged.

[0006] By forming a single-turn hob as an assembly, all processing of the tip mounting seat portion can be performed by cutting, and the number of blades can be arbitrarily set. From the relationship of the arrangement of the cutting blade tips, the one-turn hobs in the middle part except for the one-turn hobs at both ends are the same, and the types are minimized.

The cutting performance of a gear cutting tool is greatly affected by the number of teeth. The greater the number of blades, the smaller the cutting allowance per cutting edge, the longer the life of the insert, the lower the cutting vibration, and the improved the surface roughness and processing accuracy. If the cutting allowance is small, the chips will be small, so there is no need to make the chip pockets so large, and the number of blades can be set accordingly.

The lead angle of the gear is determined from the relationship between the module and the pitch circle diameter. The lead angle range is calculated from the combination of pitch circle diameters commonly used for the gears of the modules m5 to m20. The range in which the number of blades can be increased is further obtained by calculation, and the cutting edge tips are arranged as if they were on a virtual lead wire having the lead angle β of 15 ° to 30 °. . If the lead angle is smaller than 15 °, the back metal of the tool body behind the cutting edge tip in the rotation direction is insufficient, so that it is not recommended.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 3 show a throw-away type hob 1 assembled and completed as a multi-turn hob.
FIG. 4 shows an end-turn hob 2 and an intermediate-turn hob 3 which are part of a single-turn hob obtained by separating the multi-turn hob.

The tool bodies of the single-turn hobbles 2 and 3 are formed in a disk shape, and a convex portion 4 having a triangular cross section is provided on the outer periphery thereof in a spiral shape. The lead angle of the spiral matches the lead angle of the hob. End faces appearing at the starting point and the ending point of the convex portion 4 making a round are pitch matching surfaces 5, both of which are on the same plane passing through the rotation axis O of the hob and are opposite to each other.

At the center of the tool body, a main shaft mounting hole 6 for mounting on a hobbing machine is formed, and a key groove 7 for engaging with a key for transmitting rotation drive is formed on an inner wall thereof. . Outside the main shaft mounting hole 6, there are four mounting holes 8 for assembly.
Drilled at equal locations. The mounting hole 8 of the intermediate winding hob 3 is a through hole through which the assembling bolt 9 passes, and the mounting hole 8 of the one end hob 2 is a counterbore hole that can be stored up to the head of the assembling bolt 9. The mounting hole 8 of the one end hob 2 is a screw hole to be screwed with the screw of the assembly bolt 9. If the pitch matching surfaces 5 of the adjacent single-wound hobbes 2 and 3 are overlapped with each other so that the protruding portions 4 are continuous and screwed together with the assembling bolts 9, the throw-away type hob 1
Is completed.

A tip mounting seat for mounting the cutting edge tip 10 is dug down on the side surface of the convex portion 4. The chip mounting seats are arranged in a zigzag and equally spaced manner from both sides of the convex portion 4. A screw hole for mounting the cutting edge tip 10 is provided in the center of the tip seat. The cutting edge tip 10 has a rectangular flat plate shape, and is used as a vertical insert type in which a long side outer surface is a rake face. As the cutting edge chip 10, two types of different types of tips, a right edge tip and a left edge tip, are prepared. Then, the cutting blade tip 10 is screwed and fixed by a fastening screw 11 through a countersink hole formed in the flat plate surface. A chip pocket 12 is provided in front of the rake face of the cutting edge chip 10.

When the cutting edge tip 10 is combined with the throw-away type hob 1, the right edge tip and the left edge tip are arranged in parallel on the parallel line of the rotation axis O. FIG. 5 is a partially enlarged view of FIG. 3. The cutting edge tip 10 also has a line connecting the top of the left edge tip of the adjacent tooth trace for the left edge tip, and an adjacent tooth trace for the right edge tip. When the line connecting the tops of the right blade tips is a throwaway type hob 1 of modules m5 to m20, the lead angle β is 15 ° to
Designed to match the 30 ° virtual lead L,
Many blades.

[0014]

According to the indexable hob of the present invention, the number of blades can be set arbitrarily by constituting it as an assembly of a single-turn hob, and the manufacture thereof can be performed by cutting. Since the optimal cutting edge arrangement is determined in relation to the size of the gear module, a throw-away type hob with a large number of teeth is realized. By using a hob with a larger number of blades than before, insert life is long, cutting vibration is small,
Gear cutting can be performed with improved processing surface conditions and processing accuracy.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a perspective view showing a part of the separated hob.

FIG. 5 is a partially enlarged view of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Throw-away type hob 2 One end hob at end 3 Hob at intermediate part 5 Tip mating surface 10 Cutting edge β β Lead angle L Lead wire O Rotating shaft

Claims (1)

[Claims] 1. A single-turn hob is constituted by mounting a rectangular flat cutting edge tip on a disk-shaped tool body in an upright and detachable manner in an insert form, and combining such a single-turn hob with a multi-turn hob. In the throwaway type hob of the modules m5 to m20 configured as above, the cutting blade tips are mounted with the right blade tip and the left blade tip arranged in a staggered manner along the tooth streak, and each cutting blade tip is In the state of being assembled in the multi-turn hob, they are arranged in parallel on the rotation axis and in parallel with each other, and at the same time, as if on a virtual lead wire having a lead angle β of 15 ° to 30 ° in relation to adjacent tooth traces. A throwaway type hob characterized by being arranged.