JPH0372407B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a throw-away hob in which a blade having a cutting tip is fixed to the outer peripheral surface of a cylindrical body.

(Prior Art) With the development of super hard alloys, rotary cutting tools are changing from conventional high-speed steel integral parts to assembled throw-away types. However, if the cutting blades rotate once in a row, it is relatively easy to machine the main body of the chip seat where the throw-away chip is attached, but the space in the direction of the rake face is often narrow due to the adjacent cutting blades, making it extremely difficult to machine. Have difficulty. Additionally, although there are cartridge and locator methods, there are often restrictions on where they can be installed, so it is more economical and performance-friendly to assemble the blade and main body in terms of materials and processing man-hours. There are many.

Furthermore, when cutting is performed in two rows, three rows, or in the form of a screw, it becomes even more difficult to grind the cutting edge or to process the chip seat in one piece. In particular, since it is an absolute requirement for a hob, which is a generating type gear cutting tool, that the cutting edges be arranged in a threaded manner, there are relatively few inventions related to indexable hobs.

(Problem to be solved by the invention) However, among this type of invention,
In order to arrange the cutting edges in a threaded manner, the blades equivalent to four teeth of the hob are inserted into a spiral guide groove provided in the main body, and A spiral strip is provided on the outer circumferential surface, a similar guide groove is drilled in the bottom surface of the blade, and the cutting edge is shifted in phase by about 1/2 pitch. However, below ~
There is a problem like this.

The spiral grooves and protruding strips provided on the main body are similar to the processing of square screws, and can be processed with high precision.
Machining the fitting part of the blade that fits into it is extremely difficult. Hobs generally have about 12 teeth in the circumferential direction, so the range of 4 teeth is 1/3 of the circumference (120°)
However, it requires a large number of man-hours and processing equipment and jigs to process a non-cylindrical object into a spiral shape on both sides within a 120° range and fit it accurately into the spiral groove of the main body. The same applies to the case where it is fitted into a protruding strip.

Replacing the tip is easy, but one blade requires a seat for 4 teeth, so it is difficult to replace the tip.
Even if a part breaks, it is necessary to replace the blade with 4 teeth.

In generating gear cutting, excessive cutting torque is applied to the hob, but since the blade is bolted at only two points on the holder, forces that move the blade in the circumferential direction and axial direction are applied, resulting in unstable cutting. becomes.

Furthermore, since no stopper is provided against the force in the circumferential direction, and the bolt is simply inserted into the hole, the tightening force of the bolt alone is insufficient to prevent the blade from moving.

Furthermore, a plurality of spiral-shaped tool rest mounting sections with a long square cross section are arranged around the outer periphery of the main body, and the blade is held in a state where it straddles the tool rest mounting sections while being supported by the back metal provided on the tool rest mounting sections. It was attached to the blade mount, and the blade was fixed by screwing a bolt from the top of the blade toward the turret mount, and the carbide tip was fixed with a bottle to the tip seats provided on both sides of the blade. (See Japanese Patent Application Laid-Open No. 52-20496).

In this case, the blade is fixed to the main body by a bolt screwed into the top, so in terms of installation space, it is difficult to attach the carbide tip to the top of the blade, especially in the case of small modules. Since the blade is positioned by making the top of the turret mounting part and the bottom of the groove of the blade come into close contact with each other, if there is a manufacturing error between the two, the blade may not be seated closely on the turret mounting part. However, problems arise in terms of assembly accuracy, and there is a risk that the tightening may loosen when a large cutting force is applied to the blade.

(Structure of the present invention) The present invention has been made to solve the problems of the conventional products described above, and it is easy to process the blade, is stable against cutting torque, has high rigidity,
The objective is to provide a throw-away hob with excellent accuracy.

That is, both side surfaces of the main body have surfaces perpendicular to the axis, a large number of protrusions are arranged spirally on the outer cylindrical surface, a blade is formed for each unit of cutting edge of the chip, and the blade is A groove with a surface parallel to both sides of the blade is provided at the front and rear ends of the blade, the protrusion of the main body is engaged with the groove of the blade, and a clamper is placed between the front and rear ends of adjacent blades to screw the blade. The blade is firmly fixed, allowing highly accurate machining of the blade, and even if the tip seat of the blade is damaged due to cutting torque, it is only necessary to replace the blade for the damaged tooth. . Furthermore, since the clamper tightens one blade from both ends, it has excellent effects such as stability against cutting torque.

(Description of Embodiments) Next, embodiments of the throw-away hob according to the present invention will be described. In other words, the present invention does not require re-grinding the rake surface and using it again and again when the cutting edge becomes worn, unlike conventional products with double-cut grinding. It is what you use.

Therefore, there is no need for the blade itself to be spiral-shaped; the cutting edge formed on the cross section at a certain position is on the spiral of the hob, and the necessary lateral angle and outer periphery angle are provided. That's fine. Therefore, the shape of the base of the blade that holds the cutting edge portion may theoretically have any shape. However, in consideration of compatibility when replacing the blade, ease of manufacturing, improvement in mounting strength, processing accuracy, etc., the simplest planar portion was selected in many examples.

First, a protrusion 4 formed on the outer peripheral surface 3 of the cylindrical main body 1 in a plane perpendicular to the axis is cut out from the main body 1 in order to increase the rigidity and to reduce the number of manufacturing steps. The number of protrusions 4 is blade 2,
There are one more pieces than the number of pieces 2'..., and the positions are scattered on the spiral of the hob, and the division pitch in the circumferential direction is made equal to the pitch of the cutting edge of the hob. Further, the protrusion 4 is provided with a stopper 5 for preventing the blade 2, which will be described later, from moving in the circumferential direction in response to cutting torque when the blade 2 is assembled into the main body 1 as shown in FIG. Furthermore, in order to determine the axial position of the blade 2 and to prevent it from moving in the axial direction, the side surface 6 is engaged with the rear end 8 of the blade 2, and the engagement recess 23 of the front end 7 of the adjacent blade 2 is engaged. and the key side surface 6, and both blades are simultaneously tightened to the main body 1 by a clamper 9 and a double screw 10.
A screw hole 11 for this purpose is bored in the protrusion 4.
At this time, the screw hole 11 and the threaded part 14 of the double screw are right-handed screws, and the screw hole 12 of the clamper 9 and the double screw 1
The threaded portion 13 of No. 0 is a left-handed thread.

The tip C of the blade is attached to the tip seat 20, and the bottom surface 16 of each blade 2, 2', 2''... is the outer peripheral surface of the main body 1 when the blade 2, 2', 2''... is attached to the normal position. 3 is processed into a circular arc surface corresponding to the outer peripheral surface so as to be in close contact with the outer peripheral surface. Further, the surface 17 of the groove A that engages with the protrusion 4 is the side surface 1 of the blade.
8 and has both ends passed through so as to fit the key side surface 6 of the protrusion 4. Further, at both ends of the bottom surface 16 of the blade, flat lands 1 perpendicular to the side surfaces 18 are provided.
9 is left, the chip seat 20 can be accurately machined using the side surface 18 and the flat land 19 as references.

Furthermore, the abutment surface 21 of the groove A for the stopper 5 of each blade is machined so that it makes surface contact with the abutment surface 22 on the stopper side, and the end surface of the front end portion 7 of the blade is machined to the extent that the double screw 10 can be inserted therein since the abutment surface 21 is not required. It is sufficient if counterbore is applied. Furthermore, each protrusion 4
The spaces B, B, . . . have been removed, and the contact surface between the main body and the blade, indicated by the outer circumferential surface 3 of the main body, is extremely small. This reduces the contact surface between the main body and the blade, reduces the error between the spiral surface of the main body and the flat surface of the blade, and allows for highly accurate assembly. Further, the height H of the front and rear ends 7 and 8 of the side surface 18 of the blade 2 is formed to be the same as or slightly higher than the height h of the stopper 5.

The assembly of the main body 1 processed as described above and the blades 2, 2', 2'', etc. is carried out at the rear end of the blade.
Assemble the blades 2', 2'', etc. with each part in contact with the protrusion 4 in the opposite direction to the direction of rotation of the hob, and then tighten the parts where the front and rear ends of the blade are adjacent to each other with the clamper 9 and the double screw 10. At this time, use the hexagonal hole 1 in the head of the double screw 10.
All you need is a hex wrench that fits 5. Note that since there is no adjacent blade on one side of the first and last blades, it is necessary to form one more protrusion 4 than the number of blades.

According to this embodiment, each base of the blade except for the inner cylindrical surface of the bottom surface 16 of the blade is entirely formed of a flat surface, and flat lands 1 are provided at both ends of the bottom surface 16.
9, the blade can be processed accurately with simple general-purpose equipment. The main body can be easily and accurately manufactured using a thread grinder, so even assembly-type rotary tools with threaded surfaces that are difficult to machine can be manufactured at low cost with good rigidity and compatibility.

(Effects of the Invention) In the present invention, as described above, a blade is formed for each unit of the cutting edge of the chip, and the groove of the blade is engaged with the protrusion provided on the outer periphery of the main body, so that when a cutting force is applied. The contact surface 21 of the groove at the rear end is the contact surface 22 of the protrusion.
, so that displacement in the circumferential direction is prevented and positioning is performed correctly. Also, only the damaged chip needs to be replaced. Furthermore, since the front and rear ends of adjacent blades can be clamped with one clamper 9, a carbide tip can be attached to the upper surface of the blade, and it can be applied not only to finishing cutting but also to generating gear cutting. Also, it can be clamped efficiently. Moreover, since the clamp can be made strong, there is almost no worry that the clamp will loosen due to large cutting forces.

In addition, the blade and main body can be manufactured without using special equipment or jigs, and it has many excellent effects such as being able to provide inexpensive products.

[Brief explanation of drawings]

FIG. 1 is a front view showing the arrangement of the blade base of an embodiment of the throw-away type hob according to the present invention, and FIG. 2 is a partial perspective view showing the assembly structure of the main body and the blade. partial perspective view,
B shows a partial perspective view of the blade, C shows a partial perspective view of the double screw, and D shows a partial perspective view of the clamper. 1...Body, 2...Blade, 2'...Blade, 3
...Outer peripheral surface of main body, 4...Protrusion, 5...Stopper, 6...
Key side surface, 7... Cutting edge end, 8... Rear end, 9... Clamper, 10... Double screw, 11... Screw hole on main body,
12... Screw hole of clamper, 13... Threaded part of double screw, 14... Threaded part of double screw, 15... Hexagonal hole of double screw, 16... Bottom surface of blade, 17... Side surface of key groove of blade, 18... Side surface of blade, 1
9... End of the bottom of the blade, 20... Tip seat, 2
1...Blade stopper contact surface, 22...Stopper contact surface.

Claims (1)

[Scope of Claims] 1. A throw-away type hob in which a throw-away type tip is attached to a tip seat of a blade, and each blade is arranged in a spiral shape on the outer circumferential surface of a main body, and the blades are arranged along the spiral with respect to the axis. a plurality of protrusions formed with perpendicular surfaces; a blade having grooves formed at the front and rear ends of a plane parallel to the side surfaces of the protrusions and a contact surface of the rear end to engage with the protrusions; A throw-away hob comprising: a clamper that is disposed at the front and rear ends of adjacent blades to engage with the protrusion and is fixed to the protrusion by screws. 2. The throw-away hob according to claim 1, wherein a thick stopper is provided on one side of the protrusion to receive the cutting force applied to the blade.