JPH0553812U - Deep hole processing tool - Google Patents

Abstract

(57) [Summary] [Purpose] When making a deep hole in a workpiece with a prepared hole, it does not reduce machining efficiency and does not cause chatter vibration. [Structure] In a deep hole machining tool for supplying a cutting fluid from between a machined hole 21 and a head 2 to eject chips through the inside of a drill, a machining tip 7 attached to the head 2 and a tip 7 A main cutting edge 8 formed at a right angle to the feed direction of the head 2, and first and second guides arranged on the outer periphery of the head 2 at two positions facing each other in the direction of the main component force applied to the main cutting edge 8. The pads 4 and 6 and the third guide pad 5 arranged on the outer circumference of the head 2 and in the back force direction between the first and second guide pads 4 and 6.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 This invention relates to a deep hole drilling tool. More specifically, the present invention relates to a deep hole machining tool that does not cause chatter vibration when machining a deep hole of a workpiece having a prepared hole.

[0002]

[Prior art]

 When making a deep hole with a relatively small diameter, for example, when drilling a barrel, there are cases where the hole length reaches 100 times the hole diameter. If these deep holes are machined with ordinary drills, not only are they inefficient but also their accuracy is insufficient. Therefore, a gun drill that supplies cutting oil through the inside of the drill, a BTA method that supplies cutting oil from the outside, and discharges chips through the inside of the drill are used.

However, even with these gun drills or BTA methods, chatter vibrations may occur during machining because the rod that supports the bit becomes long. When this chatter vibration occurs, vibration marks are formed on the machined surface and the surface roughness deteriorates, resulting in an unsatisfactory product. Therefore, cutting, feeding speed, etc. are reduced during machining.

[0004]

[Problems to be solved by the device]

 Deep hole drilling is desirable from the standpoint of machining efficiency if it is possible to machine with a large cutting or feed rate without generating chatter vibration during this machining as much as possible. This proposal was devised in this context and achieves the following objectives.

An object of the present invention is to provide a deep hole working tool that does not reduce machining efficiency and does not cause chatter vibration when a deep hole is drilled in a workpiece having a prepared hole.

[0006]

[Means for Solving the Problems]

 This device adopts the following means in order to solve the above problems.

A deep hole drilling tool for supplying a cutting fluid from between a drilled hole (21) and a head (2) to flush chips through the inside of a drill. Tip (7), a main cutting edge (8) formed on the tip (7) in a direction perpendicular to the feed direction of the head (2), and on the outer periphery of the head (2) and the main cutting edge. First and second guide pads (4) and (6) arranged at two positions facing each other in the principal force direction of (8), and on the outer circumference of the head (2) and at the first and second guide pads. A deep hole drilling tool comprising a third guide pad (5) arranged in the back force direction between (4) and (6).

[0008]

[Action]

 The chips cut by the main cutting edge 8 collide with the main flank 11 and the like in front of the main cutting edge 8 while curling and break. After this, the chips are discharged from the discharge hole 3 together with the cutting fluid. Further, the cutting resistance is supported by the deep hole 21 machined by the three guide pads 4, 5, 6.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 is a front view of this deep hole machining tool, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a left side view of FIG. A discharge hole 3 is formed at the center of a cylindrical head 2 that constitutes the deep hole machining tool 1. A large amount of cutting oil is supplied at a high pressure between the outer periphery of the head 2 and the machined hole, and the machining oil and chips are simultaneously discharged from the discharge hole 3 during machining, that is, the BTA method. A rod (not shown) is fixed to the rear end of the head 2 in correspondence with the depth of the deep hole during processing.

On the outer periphery of the head 2, three guide pads 4, 5, 6 made of super hard are arranged at intervals of 90 degrees. Two of the guide pads 4 and 5 are relatively long and are arranged from the front to the rear. The guide pad 6 is shorter than the guide pads 4 and 5 and is arranged slightly rearward. The guide pads 4 and 6 mainly support the deflection in the main component force direction, and the guide pad 5 mainly supports the back component force.

At the outer peripheral position where the guide pads 4, 5 and 6 are not arranged, a plate-shaped and square quadrilateral chip 7 is attached by brazing. The main cutting edge 8 is formed in the radial direction, and the horizontal cutting edge 9 is provided with a sub-cutting angle α. The horizontal cutting edge 9 and the main cutting edge 8 are close to 90 degrees and form a cutting edge angle θ. Further, the main cutting edge 8 and the horizontal cutting edge 9 are subjected to honing processing, grinding processing and the like with the rake face 10.

FIG. 4 shows the situation when the processed hole 21 is cut from the prepared hole 20. FIG. 5 is a diagram showing the relationship between the cutting resistance and the three component force at that time. The main component is the component in the cutting direction and the largest component, and controls the drive torque and drive force of the spindle. This main component force is mainly supported and restrained by the guide pads 4 and 6. The feed component force is a component force in the cutting feed direction. The feed component force controls the force applied to the feed mechanism and the driving power.

The back force does not consume power, but it deforms the work piece or the cutting tool to reduce the actual depth of cut and reduces the dimensional accuracy. In the case of this embodiment, the length of the main cutting edge 8 involved in cutting, that is, the cutting edge amount l (L) is shorter than that of the slanting blade, so that the variation factor of the cutting resistance is small. It is presumed that this is because the cutting edge amount l (el) is short and the fluctuation factors such as friction are reduced. The back force is mainly supported and restrained by the guide pad 5. Since vibrations due to these cutting resistances are supported and constrained by the three guide pads 4, 5 and 6, chatter vibration does not occur.

Further, since the cutting angle β is about 90 degrees, the chips are more easily discharged from the discharge hole 3 than the beveled blade. The reason for this is that the chips being cut by the oblique blade flow in a direction substantially perpendicular to the main blade and curl on the rake face 10 by the chip breaker. The curled chips collide with the inner peripheral wall surface of the machined hole and get stuck, and after the chips are increased in radius by the subsequent chips, they are broken by bending. When these phenomena occur, the cutting resistance fluctuates and causes chatter vibration.

However, since the chips are clogged in the narrow portion of the inner peripheral surface, the cutting oil and the chips are not smoothly discharged from the discharge hole 3. On the other hand, as shown in FIG. 6, in the case of this embodiment, after curling on the rake face 10, the curled chips hit the main flank face 11 or the like and break. Since the broken chips are close to the discharge hole 3 of the head 2, they are continuously and smoothly discharged from the discharge hole 3. Therefore, since the chips are discharged smoothly, the cutting resistance does not fluctuate and chatter vibration does not occur.

Regarding this deep hole machining tool, the material of the workpiece is SNCM420H, the machining diameter is φ37.5 mm (prepared hole diameter φ30 mm), the machining depth is 340 mm, and the spindle rotational speed is 650 r. p. m. , Cutting speed 76.5 m / min. , Feed rate 25 mm / min. Deep hole drilling was performed under the condition of (0.04 mm / rev.), And the surface roughness and cylindricity of the bore inner diameter surface were measured. The results are shown in FIGS. 7 (a) and 7 (b).

[0017]

[Effect of the device]

 As described above in detail, this device has enabled deep hole machining without chatter vibration. The surface roughness of the inner diameter surface of the hole was also significantly improved.

[Brief description of drawings]

FIG. 1 is a front view of a deep hole drilling tool.

FIG. 2 is a plan view of FIG.

FIG. 3 is a left side view of FIG. 1.

FIG. 4 is a cross-sectional view showing a situation of deep hole machining.

FIG. 5 is a diagram showing cutting resistance.

FIG. 6 is a diagram showing a broken state of chips.

FIG. 7 (a) is data comparing the surface roughness of the machined surface when machined with the tool of the present invention and when machined with the conventional tool. FIG. 7B shows data when comparing the cylindricity.

[Explanation of symbols]

1 ... Deep hole machining tool, 2 ... Head, 3 ... Discharge hole, 4, 5,
6 ... Guide pad, 7 ... Tip, 8 ... Main cutting edge, 10 ... Rake surface, 11 ... Main flank surface, 20 ... Prepared hole, 21 ... Machining hole

Claims (1)

[Scope of utility model registration request] 1. A deep hole machining tool for supplying a cutting fluid from between a machined hole (21) and a head (2) to cause chips to flow through the inside of a drill, which is attached to the head (2). A machining tip (7), a main cutting edge (8) formed in the tip (7) in a direction perpendicular to the feed direction of the head (2), and on the outer periphery of the head (2), and the main First and second guide pads (4) and (6) arranged at two positions facing each other in the main component force direction applied to the cutting blade (8), and on the outer circumference of the head (2) and at the first and second A deep hole drilling tool comprising a third guide pad (5) arranged between the guide pads (4) and (6) in the back force direction.