JP4644552B2 - Deep hole cutting equipment - Google Patents

Description

  The present invention relates to a deep hole cutting device in which chips generated during cutting work are discharged from a boring head discharge opening together with coolant to the outside through a hollow boring bar, and in particular, deep hole cutting using a coolant internal supply system. Regarding the device.

  In general, the cutting efficiency of deep hole machining is more dependent on the capability of discharging chips generated inside the cutting hole during machining to the outside than the capability of the tool system. For this reason, in the deep hole cutting apparatus, a hollow boring bar is used, a discharging opening is provided in the boring head, and the chip is passed through the inside of the boring bar from the discharging opening together with the coolant supplied to the cutting edge. It discharges to the outside. Thus, the coolant is supplied to the cutting edge part through an external supply method through the gap between the outer peripheral surface of the hollow boring bar and the inner peripheral surface of the cutting hole, and an internal supply method through the inside of the hollow boring bar. is there. Note that the cutting may be performed when the boring bar side is rotated or when the work material side is rotated.

  In the external supply method, as shown in FIG. 7, a coolant supply jacket 41 that oil-tightly surrounds the hollow boring bar 40 is used, and this jacket 41 is pressed against the work material W via the seal ring 42. In this state, the coolant C is introduced into the jacket 41 from the introduction port 43 at a high pressure, so that the gap T between the outer peripheral surface of the boring bar 40 and the inner peripheral surface of the cutting hole H moves toward the cutting blade 45 of the boring head 44. The coolant C is supplied to the hollow portion 47 of the boring bar 40 from the discharge opening 46 facing the cutting edge 45 of the boring head 44 together with the chips S that generate the coolant C, and is discharged to the outside.

  However, in such an external supply system, as the cutting hole H becomes deeper, the coolant supply path becomes longer and the pressure loss due to the flow resistance increases, so that the cutting resistance and the cutting resistance due to insufficient supply of the coolant C to the cutting site. As the heat generation increases, the discharge ability of the chips S via the coolant C decreases, and there is a problem that the cutting efficiency is deteriorated, and it is necessary to set the coolant supply pressure high to compensate for the pressure loss, There was a problem that the equipment cost and energy cost for that purpose increased.

  On the other hand, in the internal supply system, as shown in FIG. 6, the hollow boring bar 30 has a double cylinder structure, and is introduced into a coolant supply path 30 a formed between the inner cylinder 31 and the outer cylinder 32. The high-pressure coolant C thus supplied is supplied from the coolant outlet 34 of the boring head 33 to the cutting blade 35 side, and is discharged from the discharge opening 36 facing the cutting blade 35 of the boring head 33 together with the chips S that generate the coolant C. It flows into the discharge path 30b comprised inside the cylinder 31, and discharges outside. Reference numeral 37 denotes a guide bush fitted to the boring bar 30 and presses the work material W through a seal ring 37a.

  As shown in FIG. 5, the inner cylinder 31 of the boring bar 30 is formed by closely fitting a distal end portion 31a having an enlarged diameter to an annular stepped portion 33a facing the proximal end provided on the inner periphery of the boring head 33. The head side seals between the coolant supply path 30a and the discharge path 30b. In addition, a plurality of small holes are arranged on the outer periphery of the base side of the coolant outlet 34 of the boring head 34 in order to suppress the backflow of the coolant C from the coolant outlet 34 toward the inlet of the cutting hole H. The labyrinth seal part 38 which consists of an annular projecting edge is provided.

  In the case of this internal supply method, the length of the coolant supply path is constant, and there is no change in the flow path resistance (internal resistance between the inner and outer cylinders 31, 32) due to the depth of the cutting hole H. Even if this occurs, the cutting resistance and heat generation will not increase, and the chip S discharge capacity will not decrease, so that the cutting efficiency will not be deteriorated as in the above-described external supply system, and the coolant supply pressure must be set high. There is also an excellent advantage.

  By the way, if the hole diameter of the cutting hole H becomes small, a thin boring bar corresponding to the hole diameter is used. In particular, in the double cylindrical boring bar 30 used for the internal supply method, the flow path of the coolant supply path 30a and the discharge path 30b. In order to secure the cross-sectional area, the thickness of the inner cylinder 31 is inevitably set to be thin. However, a metal pipe made of stainless steel or the like is generally used for the inner cylinder 31. However, since the tensile strength is weak in the thin metal pipe, the expanded tip 31 a is bent by the supply pressure of the coolant C. However, when it is severe, it is distorted and deformed, whereby the seal between the coolant supply path 30a and the discharge path 30b on the head side is broken, and the supply of the coolant C to the cutting site and the discharge of chips are not smoothly performed. Therefore, the deep hole machining by the conventional coolant internal supply type deep hole cutting apparatus has a drawback that the hole diameter is restricted to a certain extent (usually, a hole diameter of 18 mm or more).

  In view of the above circumstances, the present invention is a deep hole cutting device that discharges chips generated during a cutting process from the discharge opening of the boring head to the outside through the inside of the hollow boring bar together with the coolant. It is an object of the present invention to provide a supply-type deep hole cutting device that can be suitably applied to deep hole machining with a small diameter of the cut hole without any problem.

  In order to achieve the above object, according to the invention of claim 1, the boring bar 1 has a coolant supply passage 5 between the inner and outer cylinders 4, 3 and a discharge path 6 inside the inner cylinder 4. A discharge opening 21 communicating with the discharge path 5 is formed on the front end surface of the boring head 2 provided at the front end of the boring bar 1, and the chip S generated during the cutting process is formed. In the deep hole cutting apparatus, the boring head 2 is discharged to the outside through the discharge passage 5 from the discharge opening 21 together with the coolant C supplied to the cutting blade 9 side from the coolant outlet port 22 on the peripheral surface of the boring head 2. The front end portion 4a of the inner cylinder 4 of the bar 1 is screwed to a screw portion (female screw portion 8b) provided on the boring head 2 side by a screw portion (male screw portion 8a) provided on the peripheral surface thereof. When To have.

  According to a second aspect of the present invention, in the deep hole cutting apparatus according to the first aspect, the boring head 2 is made of an independent member that is detachable from the boring bar 1 and is formed on the outer periphery of the rear portion 2c side. 2 has a male screw portion 7a that is screwed to the female screw portion 7b on the inner periphery of the outer cylinder 3, and has a female screw portion 8b that is screwed to the male screw portion 8a on the outer periphery of the inner tube 4 of the boring bar 1 on the inner periphery. It is supposed to be.

  According to the first aspect of the invention, as a deep hole cutting device of the coolant internal supply type, the double cylindrical boring bar has a small diameter corresponding to deep hole processing with a small cutting hole diameter, and the inner cylinder becomes thin. However, since the tip of the inner cylinder is screwed to the boring head with a thread, the tip is bent or deformed by the coolant supply pressure in the coolant supply path between the inner and outer cylinders. No, the seal on the head side of the coolant supply path and the discharge path inside the inner cylinder is reliably maintained, so that the coolant C is smoothly supplied to the cutting site and the chips are discharged smoothly, and good deep hole workability is achieved. Is obtained.

  According to the invention of claim 2, since the boring head can be attached to and detached from the inner and outer cylinders of the boring bar with screws, only the boring head is detached and replaced when each part of the boring head is worn or damaged. Thus, there are advantages that the maintenance cost can be reduced, and that the work of attaching / detaching can be easily performed.

  FIG. 1 shows a deep hole cutting apparatus according to an embodiment of the present invention. This deep hole cutting device is a gun drill type of coolant supply system, and a substantially round shaft-shaped drive shaft 12 is provided in the front and rear of a substantially cylindrical coolant supply / discharge casing 10 having a coolant supply port 10a and a discharge port 10b. The bearings 11 and 11 are rotatably held concentrically. This drive shaft 12 is provided with a taper collet chuck 13 at the front end protruding from the casing 10, and the boring bar 1 having a boring head 2 attached to the tip in a tool holding hole 12a extending from the front end to the middle in the longitudinal direction. The base side is inserted and fastened and fixed by the chuck 13, and the rear end portion 12b with a key groove protruding from the casing 10 is connected to a spindle of a machine tool or the like to rotate.

  Thus, the drive shaft 12 is formed with a radial flow path 12d that communicates the inner portion of the tool holding hole 12a with the annular groove 12c provided on the outer periphery of the drive shaft 12, and the inner portion of the tool holding hole 12a. An oblique discharge channel hole 12e extending from the end to the outer peripheral surface at the rear of the annular groove 12c is provided. On the other hand, the coolant supply / discharge casing 10 has a ring member 14 fitted on the drive shaft 12, and the radial flow path 14 a provided in the ring member 14 includes the annular groove 12 c of the ring member 14 and the coolant supply port 10 a. And communicate with. Further, an annular discharge space 10c surrounding the drive shaft 12 is provided behind the ring member 14 in the casing 10, and a discharge port 10b communicates with the annular discharge space 10c, and a discharge passage hole of the drive shaft 12 is provided. An outlet 12e faces the annular discharge space 10c. Reference numeral 15 denotes a mechanical seal ring that is externally fitted to the drive shaft 12 inside each bearing 11, and 16 is a cock that is screwed from the outside of the casing 10 and engaged with the ring member 14.

  The boring bar 1 has a double cylinder structure in which a thin tube-shaped inner cylinder 4 made of a metal such as stainless steel is disposed in a thick outer cylinder 3, and an annular space between the inner and outer cylinders 4 and 3 is a coolant supply path. 5 and the inner side of the inner cylinder 4 constitutes a discharge path 6. The coolant supply passage 5 is closed by press-fitting / tightly fitting the rear end 4b of the inner cylinder 4 to the rear inner periphery 3b of the outer cylinder 3 whose rear end is reduced in diameter, but before the closed position. The side channel hole 5a communicates with the side channel hole 5a provided in the outer cylinder 3, and the side channel hole 5a faces the annular concave surface part 5b provided on the outer peripheral surface of the rear end portion of the outer cylinder 3, and the annular concave surface part 5b When the boring bar 1 is mounted on the drive shaft 12, it faces the radial flow path 12 d of the drive shaft 12 to communicate with the coolant supply port 10 a of the coolant supply / discharge casing 10. On the other hand, the discharge path 6 communicates with the discharge port 10 b from the rear end opening of the boring bar 1 through the discharge flow path hole 12 e of the drive shaft 12 and the annular discharge space 10 c of the casing 10.

  Further, as shown in FIG. 2 and FIG. 3 in which the inside of the phantom line A in the figure is enlarged, a female screw portion 7b is formed on the inner periphery of the outer cylinder 3 at the front end portion of the boring bar 1. At the same time, the inner cylinder 4 protrudes forward from the outer cylinder 3, and a male screw portion 8a is formed on the outer periphery of the protruding front end portion 4a.

  As shown in FIGS. 4A and 4B in addition to FIGS. 2 and 3, the boring head 2 is an independent member having a substantially cylindrical shape as a whole, and is a discharge opening 21 that opens from the front end surface to the side surface. The front part 2a has a middle part 2b in which a labyrinth seal part 22 composed of a plurality of annular protrusions is formed on the outer periphery, and the rear part 2c has an external thread part 7a engraved on the outer periphery. A cutting blade 9 made of a throw-away tip is attached to the front portion 2a on an edge surface of the discharge opening 21 along the substantially head radial direction, and a guide pad 24 made of cemented carbide is provided at two locations on the peripheral surface. A plurality of coolant outlets 23 are opened on the outer periphery of the portion that is attached and moves from the front portion 2a to the intermediate portion 2b. The center hole 20 of the boring head 2 has a reduced diameter on the front end side facing the discharge opening 21, and a female screw portion 8 b is formed on the inner periphery of the reduced diameter portion 25.

  When the boring head 2 is attached to the boring bar 1, the male threaded portion 7a of the rear portion 2c is screwed into the female threaded portion 7b of the front end portion 31a of the outer cylinder 3 as shown in FIGS. As a result, both 1 and 2 are firmly connected and integrated, while the male threaded portion 8a of the front end 4a of the inner cylinder 4 is screwed into the female threaded portion 8b inside the boring head 2, thereby The discharge opening 21 communicates with the discharge path 6 of the boring bar 1, and the front end side of the coolant supply path 8 is blocked from the discharge opening 21 and communicates with the coolant outlet 7.

  In the deep hole cutting by the deep hole cutting device having the above-described configuration, the high pressure coolant C is supplied from the coolant supply port 10a of the coolant supply / discharge casing 10, and the boring bar 1 is moved in the direction of arrow F in FIG. The boring head 2 is pressed against the work material W through an appropriate guide bushing (for example, the guide bushing 37 shown in FIG. 6), and the work material is cut by the cutting blade 9. W is cut to form a cutting hole H.

  At this time, the coolant C supplied is the radial flow path 14 a of the ring member 14 → the annular groove 12 c of the drive shaft 12 → the same radial direction flow path 12 d → the annular concave surface portion 5 b of the boring bar 1 → the same side flow path hole. 5a sequentially flows into the coolant supply path 5, passes through the coolant supply path 5 and is led out to the clearance between the boring head 2 and the cutting hole H from the coolant outlet 23, and reaches the cutting site by the cutting edge 9. Then, it flows into the discharge path 6 in the boring bar 1 from the discharge opening 21 together with the chips S generated by cutting, and from the rear end opening of the boring bar 1 to the discharge flow path hole 12e of the drive shaft 12 and the casing 10. Through the annular discharge space 10c, the chips S are discharged to the outside from the discharge port 10b.

  Thus, when the boring bar 1 is thin corresponding to the small-diameter cutting hole H, it is necessary to use a small-diameter and thin-walled metal tube for the inner cylinder 4, but this deep hole cutting is necessary. In the configuration of the apparatus, the distal end portion 4a of the inner cylinder 4 is screwed into the inner periphery of the boring head 2 with a screw, so that the distal end portion 4a may be bent or distorted by the supply pressure of the coolant C. Therefore, the seal between the coolant supply path 5 and the discharge path 6 on the head 2 side is reliably maintained, and the coolant C is smoothly supplied to the cutting site and the chips are discharged smoothly. Hole workability can be obtained.

  Further, in the above configuration, the boring head 2 can be attached to and detached from the inner and outer cylinders 4 and 3 of the boring bar 1 with screws, and when the parts of the boring head 2 are worn or damaged, only the boring head 2 is detached. Since replacement only has to be performed, the maintenance cost can be reduced, and the work of attaching / detaching can be easily performed.

  In the illustrated deep hole cutting, the boring bar 1 is rotationally driven. However, the work material W is necessary as necessary, for example, in the case where the lengthwise cutting hole H is provided in the columnar or bar-shaped work material W. It is also possible to perform the processing by rotationally driving the side.

  In the above embodiment, the rear portion 2c of the boring head 2 is fitted into the outer cylinder 3 of the boring bar 1, but the male screw portion 8a and the female screw portion 8b are reversed, and the outer cylinder 3 side is placed on the boring head 2 side. It is good also as a structure fitted in the rear part 2c. In addition, although complicated in structure, a short cylindrical portion is integrally formed inside the boring head 2, a male screw portion provided on the outer periphery of the cylindrical portion, and an inner periphery of the front end portion 4 c of the inner tube 4 of the boring bar 1. It is also possible to employ a configuration in which a female screw portion provided on the screw is screwed together. Further, the boring head 2 is replaced with an annular projecting edge of the labyrinth seal portion 22 in order to prevent the coolant C led out from the coolant lead-out port 23. A spiral ridge may be provided and set such that a propulsive force toward the cutting edge by the spiral ridge acts with rotation during cutting.

  In addition, in the present invention, the number and shape of the cutting edge in the boring head, the shape of the discharge opening, the boring bar drive mechanism, the coolant supply mechanism, the discharge of coolant and chips through the boring bar to the outside. Various design changes other than the embodiment can be made for the detailed configuration such as the mechanism.

It is a vertical side view of the deep hole cutting device which concerns on one Embodiment of this invention. It is a vertical side view of the boring head vicinity during cutting by the deep hole cutting device. FIG. 3 is an enlarged view inside a virtual line circle a in FIG. The boring head used for the deep hole cutting device is shown, (a) is a front view, and (b) is a side view. It is a vertical side view of the vicinity of the boring head during cutting by a conventional coolant internal supply type deep hole cutting device. It is a vertical side view which shows the cutting state by the deep hole cutting device of the conventional coolant internal supply system. It is a vertical side view which shows the cutting state by the conventional deep hole cutting device of a coolant external supply system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Boring bar 2 Boring head 3 Outer cylinder 3a Front end part 4 Inner cylinder 4a Front end part 5 Coolant supply path 6 Discharge path 7a, 8a Male thread part 7b, 8b Female thread part 9 Cutting edge 20 Center hole 21 Discharge opening 23 Coolant outlet C Coolant H Cutting hole S Chip W Work material

Claims (2)

The boring bar is configured as a double cylinder with the coolant supply path between the inner and outer cylinders and the inner cylinder inside as a discharge path, and a discharge opening communicating with the discharge path on the front end surface of the boring head provided at the front end of the boring bar A deep hole in which a chip is formed and chips generated during cutting are discharged from the discharge opening to the outside through the discharge passage together with the coolant supplied from the coolant outlet on the peripheral surface of the boring head to the cutting edge. In cutting equipment,
A deep hole cutting device, wherein a front end portion of an inner cylinder of the boring bar is screwed to a screw portion provided on the boring head side by a screw portion provided on a peripheral surface thereof.   The boring head is made of an independent member that can be attached to and detached from the boring bar. The boring head has a male threaded portion that engages with a female threaded portion on the inner circumference of the outer cylinder of the boring bar on the outer periphery on the rear side. 2. The deep hole cutting device according to claim 1, further comprising a female screw portion that is screwed into a male screw portion on an outer periphery of the inner cylinder of the bar.

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