Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
  • B23G5/00—Thread-cutting tools; Die-heads
  • B23G5/20—Thread-cutting tools; Die-heads combined with other tools, e.g. drills
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
  • B23G2200/00—Details of threading tools
  • B23G2200/14—Multifunctional threading tools
  • B23G2200/143—Tools comprising means for drilling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
  • B23G2200/00—Details of threading tools
  • B23G2200/14—Multifunctional threading tools
  • B23G2200/148—Tools having means for countersinking
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
  • B23G2240/00—Details of equipment for threading other than threading tools, details of the threading process
  • B23G2240/36—Methods of threading not otherwise provided for

Definitions

• the present invention relates to a method for producing a threaded bore with countersinking and a drilling tool for carrying out this method.
• This hole can be configured both as a blind hole and as a through hole. If the hole in a workpiece newly introduced by way of machining, it is called core drilling. If an already preformed core hole is drilled to the specified size, this is called boring. Furthermore, it is known to expediformen in the cylindrical side walls of holes thread. A well-known threading process is tapping. For this purpose carries a special drill on its outer surface thread cutting teeth for molding the thread in the bore wall. Finally, it is known to form a countersink at the edge of the hole. This countersink at the edge of the hole and thus also at the inner thread start serves as a centering aid or as an insertion bevel when the screw carrying an external thread is screwed into the threaded hole.
• step drills The disadvantage of such step drills is the fact that with a step drill always only one Core hole or threaded hole with a predefined Depth can be made. For the production of core holes or tapped holes with different depths, different step drills adapted to the respective depth are required.
• the disadvantage here is the required tool change from the combination taps to the countersinking tool on the one hand and the additional assignment of a tool slot in the tool magazine by the countersinking tool on the other hand.
• the invention is therefore based on the object to design a method for producing a threaded hole with countersinking so that the lead time for the production of the threaded hole is further reduced and the method is further simplified.
• This object is achieved by the method specified in claim 1.
• the object of the invention is to present a tool suitable for carrying out this method.
• This object is achieved by the combination of features of claim 3.
• the restituted claims contain in part moderate and partially inventive for further developments of claimed in the respective independent claims invention.
• the method according to the invention makes use of the fact that processing machines with three-dimensionally adjustable work spindles are used in modern production technology.
• machine tools that are capable of producing internal threads by way of so-called screw interpolation are suitable for carrying out the method.
• screw interpolation of the main spindle of the machine tool a circular motion and a linear motion for generating the helix are superimposed. In this way, all thread combinations can be produced for example with the help of thread milling.
• a drill kinematically coupled to the main spindle usually a drill clamped into the chuck of the drill, is introduced into the workpiece in a first working stroke in the central longitudinal direction of the main spindle in order to drill out a core hole or to drill a molded core hole.
• a drill clamped into the chuck of the drill With attached to the peripheral surface of the drill tapping teeth an internal thread is cut at the same time with the drilling process in the side wall of the drilled core hole. It thus creates the threaded hole.
• this first step immediately follows the second process step without a tool change.
• the main spindle After moving out of the tool, so the drill from the threaded hole, the main spindle approaches at a right angle to its central longitudinal axis and thus to the drilling direction to the edge of the threaded bore and guides the drill with a circular motion along the edge of the core hole and thereby cuts the countersink in the edge of the threaded hole. After completion of this second operation, the threaded hole with countersink is completely manufactured and used.
• the drill is first immersed analogously to the procedure in the screw interpolation by the full amount of the depth of the countersink in the central longitudinal direction of the tool spindle in the threaded hole. After immersion, the drill moves a quarter circle entry loop, - A - cuts the countersink into the edge of the tapped hole, then returns to the center of the tapped hole with a quarter circle extension loop to leave the hole.
• the method according to the invention can also be realized with other entry and exit loops.
• the main advantage of the method according to the invention is that the tool change from the combined tapping tool to the countersinking tool is completely eliminated.
• the method according to the invention it is possible to realize both the boring or boring of the core hole and the cutting of the thread as well as the lowering of the hole edge or bore edge with a tool in one clamping.
• the corresponding space in the tool magazine for the countersinking tool is no longer needed.
• Another tool can be placed in the tool magazine instead of the countersink tool. This has the advantage that the main cycle for the tool magazine is extended, so that the intervals for the tool change in the tool magazine decrease analogously. The associated time savings and the resulting cost reduction is evident.
• Claims 3 to 6 relate to a drill adapted for carrying out the method.
• the drill carries on its face at least one main cutting edge.
• Each drill main cutting edge corresponds to two additional drill bit cutting edges on the drill circumference.
• the auxiliary flanks associated with the drill bit cutters each carry the thread cutting teeth.
• a chamfer is formed between each of the main faces at the drill bit end and the adjoining minor faces on the drill shank. This chamfer runs obliquely in such a way that an oblique cutting bevel forms between the main cutting edge and the secondary cutting edge assigned to it for stock removal in the second process step.
• the chamfer in the area between the drill face and drill shank improves chip removal during drilling, namely when the main cutting edges are cut into the workpiece.
• the chamfer thus has a double function. On the one hand, it is the mold for making the countersink. On the other hand, it favors the chip removal of the drill during the drilling process.
• the helix angle of the countersink can be chosen arbitrarily. In general, standardized angle dimensions are selected for the helix angle of the countersink. An example of such a standard is the DIN 76, Part 3. There are specified for internal thread or nut thread root holes, each having a countersink at the threaded recess or thread. The outer diameter of the countersink corresponds to the standard maximum of 1.05 times the thread diameter d. For this diameter ratio results in an opening angle ß of the countersinking according to DIN 76 of 120 °.
• the opening angle ⁇ corresponds to twice the amount of helix angle of the counterbore. Since the chamfer angle of the chamfer relative to the central longitudinal axis of the drill corresponds to the helix angle of the countersink, the opening angle ⁇ of 120 ° is made with a bevel with a helix angle of 60 °.
• the geometry of the countersinking produced with the method according to the invention on the one hand and the drill according to the invention for carrying out the method on the other hand always depends on the geometry of the chamfer formed on the drill.
• the width of the chamfer on the drill is slightly larger than the width of the countersink to be machined with the chamfer.
• the chamfer width corresponds to 105% of the width of the countersink to be produced.
• the drill it is provided to install one or more cooling channels in the drill.
• a liquid coolant can thus be transported to the site of action.
• the cooling lubricant serves to remove the chips produced during drilling.
• the chips are, as it were, flushed out of the bore with the aid of the liquid coolant, or washed away from the work site of the drill on the workpiece.
• the cooling lubricant thus also serves to improve chip removal.
• the cooling channel opens in the area of the open areas or the drill cross-section.
• FIG. 2 is a perspective view of the drill head and a portion of the adjoining drill shank
• FIG. 3 is an enlarged side view of the drill head of the drill shown in FIG. 1
• FIG. 4 is a plan view of the end face of the drill head according to arrow IV in FIG. 3
• FIG. 5 is a sectional side view of the drill shown in FIG. 1
• FIG. 6 is an enlarged view of the tip of the drill head of the drill as shown in FIG. 5.
• Fig. 1 In Fig. 1 can be seen the cylindrical drill shank 1 with a square 2 at its free end.
• the square 2 is an anti-twist device for the drill chucked in the chuck of a machine tool.
• the drill head 4 is formed at the free end of the drill shank 1 facing away from the square 2 in the central longitudinal direction 3.
• the drill head 4 consists of several, in the exemplary embodiment four flutes 5.
• ribs of the drill body are formed between the flutes, which carry 7 cutting teeth on their outer surfaces, the secondary flanks.
• the cutting teeth 8 are used for actual cutting of the thread, while the guide teeth 18 guide the drill during the further drilling or threading process already cut internal thread.
• the Bohrhaupting 10 are in the center of the drill head 4 of the cooling channel opening 11 is broken.
• the cooling channel opening 11 of the drill in the central longitudinal direction 3 passes through the cooling channel 12 opens for the discharge of cooling lubricant to the site of action during the drilling process.
• the main relief surfaces 13 are formed on the front side of the drill head 4. Between the main free surfaces 13 and the secondary flanks 7, the oblique chamfer 14 is formed on the drill head 4.
• the helix angle 16 of the chamfer 14 in the exemplary embodiment is 38 °.
• a chamfer 14 with a helix angle 16 of 60 ° is selected.
• the chamfer width 19 is preferably slightly larger than the width of the countersink made with the chamfer 14.
• the operation of the drill shown in the embodiment is the following: For boring a core hole to a threaded hole, the drill moves into the preformed core hole and cuts this core hole with his Bohrhauptberger 10 and formed on the Mauok vom 7 Bohrnebener to measure. At the same time, the thread cutting teeth 8 arranged on the secondary relief surfaces 7 cut a thread into the inner wall of the core hole, so that a threaded bore is formed.
• the drill After completing the threaded hole, the drill again moves in the central longitudinal direction 3 along its central longitudinal axis 15 out of the threaded hole.
• the main spindle of the machine tool which is aligned with the central longitudinal axis 15, then moves the drill in the orthogonal direction 17 at right angles to the central longitudinal direction 3 to the edge of the hole.
• the chamfer 14 engages the bore edge and the cutting edges associated with the chamfer 14 cut the countersink into the bore edge by rotation of the drill in the direction of rotation 6 and simultaneous circular motion of the drill controlled by the main spindle of the machine tool.
• the drill bit After completion of the countersink, the drill bit is disengaged from the hole edge forming the thread by means of a quarter-circle extension loop and moved away from the workpiece. The threaded hole with countersink at the start of the thread is thereby completely completed.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Drilling Tools (AREA)
• Milling Processes (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38089109

Family Applications (1)

Country Status (5)

Cited By (3)

Families Citing this family (4)

Citations (10)

• 2006
  • 2006-02-09 DE DE200610005887 patent/DE102006005887A1/de not_active Withdrawn
• 2007
  • 2007-02-06 JP JP2008553662A patent/JP2009525884A/ja active Pending
  • 2007-02-06 CN CNA200780004781XA patent/CN101378872A/zh active Pending
  • 2007-02-06 EP EP07703291A patent/EP1846188A1/de not_active Withdrawn
  • 2007-02-06 WO PCT/EP2007/000982 patent/WO2007090600A1/de not_active Ceased

Patent Citations (10)

Non-Patent Citations (1)

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