JPH0763894B2 - Tap with oil hole - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an oil hole tap for forming a female screw on an inner periphery of a machined hole, which is particularly suitable for machining a through hole.

(Prior Art) A conventional tap with an oil hole is, as shown in FIG. 3, an axially twisted groove or a straight groove (4) with respect to a cutting edge (1) arranged along a helical line (S). Is formed and an oil hole (5) is formed in the shaft center.
Is open. There are taps for blind holes and through holes. For through hole processing, the tip of the oil hole is filled with a filling metal (15), and the bite cut-up portion (7a) is adjacent to the oil hole (5) at right angles. The one provided with an oil ejection hole (12a) opening to the groove (4) is usually used. When drilling a blind hole, use one without a padding (15) at the tip of the oil hole so that the oil on the tip side does not stay in the blind hole. The oil that has flowed back in the blind hole of the object passes through the groove (4) to discharge chips.

On the other hand, in through-hole machining, as described in FIG. 3, oil is ejected from the oil ejection hole (12a) orthogonal to the oil hole (5), ejected onto the hole wall surface of the workpiece, and jetted on the hole wall surface. Is divided into two and jetted in the direction of the tip of the chamfered blade (7) and in the direction of the thread forming cutting edge (1). Therefore, the oil jetted in the thread forming cutting edge direction (1) is discharged together with the cutting chips through the groove (4) from the hole of the work piece on the tap insertion side to the tip direction of the bite blade (7). The jetted oil is pushed in the tip direction of the bite blade together with the chips cut by the bite blade, passes through the tip side of the groove (4), and is discharged to the outside from the hole on the side opposite to the tap of the work piece. .

(Problems to be solved by the invention) However, in the tap with an oil hole having the oil ejection hole (12a), the ejection hole (12a) orthogonal to the oil hole (5) is provided in the vicinity of the chamfered cut-up portion (7a). Since it is opened in the groove (4), the strength is weak, and compressive stress and torsion moment are applied as concentrated stress at the time of cutting to the chamfered cut-up portion (7a) provided with the ejection hole, which may cause tap breakage. There was a problem of becoming. In addition, there is a limit to the amount of oil jetted, and if oil is jetted in two directions, the chip discharge force becomes extremely weak and cutting continues without being completely discharged, so the cutting edge bites the chip that is not discharged. However, there are problems that the wear of the cutting edge is accelerated and that the chipping of the cutting edge is caused to shorten the life of the tap.

An object of the present invention is to provide a tap with an oil hole which does not cause breakage of the conventional tap, supplies oil sufficiently to the cutting surface, promotes discharge of chips on the cutting surface, and has a long life without biting or wear. It is in.

(Means for Solving the Problems) In order to achieve the above object, a description will be given with reference numerals with reference to FIG. 1. In the present invention, the spiral winding (S) is used.
Has a cutting edge (1) arranged along the longitudinal direction and a plurality of grooves (4) formed in the longitudinal direction, and communicates with an oil hole (5) bored in the axial center of the main body and is the same as the plurality of grooves. The protruding part (10) having a diameter smaller than that of the cutting edge at the tip of the bite-up part (7a) provided with a jetting path (12) opening radially in phase and obliquely in the handle side and having no cutting edge is the main body. The problem was solved by forming it at the tip of the blade, that is, the tip of the cut-up part (7a) with oil, and jetting the oil obliquely toward the handle side.

(Function) The oil hole (5) is connected to the oil hole (5) in the protrusion (10) having a diameter smaller than the cutting edge of the tip of the bite-up cut-out portion formed at the tip of the bite-up cut-out portion (7a) and having no cutting edge. Since the ejection path (12) that opens diagonally to the side is provided, cutting etc. is not performed at the protrusion (10) and no chips are generated, and the chips generated by the cutting blade are located on the handle side of the ejection hole. And the oblique hole ejection path (1
The oil ejected from 2) is ejected in one direction toward the cutting up part (7a), the groove (4), the cutting edge (7) and the cutting edge (1), so the ejection force is dispersed. All the chips generated by the cut-up cutting portion (7a), the cutting blade (1), etc. without being cut off are discharged through the groove (4) to the outside of the hole of the work piece.
Since oil is ejected and fine chips are discharged even during reverse rotation, the chips do not get caught in the cutting edge due to reverse rotation, the taps are smoothly extracted, and the screw holes are cleaned.

(Example) The tap of this invention is demonstrated by an Example. In FIG. 1, when a groove (4) orthogonal to the advance angle (α) of the tap cutting edge (1) of the spiral line (S) is formed, a advance flank (2) and a follower flank (3) are formed. It The cutting edge angle (β) shown in FIG. 5 of each formed flank is the same. An oil hole (5) is formed in the axial center of the main body so as to penetrate from an end face (6) on the handle side to an end face (8) of a raised bite portion (7a) provided with a biting blade (7). A female screw (9a) is provided on the oil hole opening (9) on the 8) side. As shown in FIG. 2 (a), the protruding member (10) formed separately from the main body has a straight hole (11) and an oblique ejection hole (12) communicating with the straight hole (11).
That is, the ejection path is formed. Screw the male screw (13) of the protruding member (10) into the female screw (9a) of the oil hole opening,
The oil hole (5) communicates with the straight hole (11). The oblique ejection hole (12) is directed toward the groove (4), and oil is made to flow out to the groove bottom (4a). Further, the outer diameter of the protruding member (10) is smaller than the cutting edge at the tip of the edging cut-up portion, and no cutting edge is provided.

As a method of attaching the protruding member, in addition to the screwing shown in the embodiment of FIG. 2 (a), the protruding member (10) is made of an elastic body as shown in FIG. 2 (b), and the convex portion (14) is formed. At the same time, a recess is formed in the opening (9) of the oil hole (5), and the protrusion (14) of the protruding member (10) is pushed into the recess and fitted. It is also possible to form an inverse taper that spreads inward from the oil hole opening, attach a taper matching the taper to the protruding member (10), and press the protruding member into the oil hole opening. Oil is projected through the oil hole (5). Straight hole (1
1), further ejected from the oblique ejection hole (12) into the groove (4), and the chips accumulated in the groove (4) are discharged outward from the hole of the work piece.

Since the cutting edge angle (β) of the leading flank and the trailing flank is different in the conventional type as shown in FIG. 5, the cutting edge wear is not uniform and the re-grinding margin is increased, and the re-grinding is increased. There was a problem that the man-hours are large and the tool life is short, but when a groove orthogonal to the cutting edge advance angle of the spiral line is formed as in this embodiment, the cutting flank angle of the leading flank and the trailing flank become the same. The balance of the cutting edge is improved and the wear of the cutting edge due to cutting can be equalized. The life of the cutting edge is extended. Further, the re-grinding of the cutting edge becomes easy. Further, FIG. 4 shows an embodiment in which the shape of the groove (4) is different from that of FIG. 1 and the present invention is applied to a tap in which the groove (4) is a straight groove parallel to the axis. Show.

If the tap has a small outer diameter or does not require re-grinding of the cutting edge, the function can be sufficiently achieved even if the protruding member is fixed to the oil hole with an adhesive, brazing, or a laser beam.

Further, the embodiment shown in FIG. 6 and FIG. 7 shows the one in which the protruding member (10a) is provided integrally with the main body instead of the protruding member being a separate body as in the above-described embodiments.

Fig. 6 shows a protruding part (10
a) is integrally provided and an oil hole (5) is bored in the shaft center, and a through hole (5a) is further formed in the protrusion (10a). Also, the protrusion (1
Screw the oil stopper (17) to the tip of 0a). Protrusion (10
A jet passage (12) communicating with the oil hole (5) and opening obliquely in the handle side direction is formed in a), and the jet passage (12) faces the cutting edge of the groove or the vicinity thereof. ing. The outer diameter of the protrusion (10a) is smaller than the diameter of the processed hole, and the oil stopper (17) is fixed to the through hole (5a). The oil ejected from the oblique hole ejection passage (12) has a eclipsed cut-up portion (7a),
The chips are ejected in one direction toward the vicinity of the groove (4), the edging blade (7) and the cutting blade (1), and the discharge of chips is good. In FIG. 7, the oil hole (5) in FIG. 6 is used as a blind hole, and a center hole (18) is provided at the tip of the protrusion (10a).

(Effects of the Invention) The present invention forms a protrusion having a diameter smaller than the cutting edge of the tip of the edging cut-up portion and having no cutting edge, as described above, and the protrusion has the above Since the ejection passages communicating with the oil holes and arranged radially in the same phase as the groove and opening obliquely to the handle side are provided, the chips generated by the cutting blade are generated on the handle side of the ejection route, and the oil is the handle. Since all the chips that are ejected in the oblique direction to the side are discharged from the hole of the work piece, there is no bite of the chips in the cutting edge, abnormal wear of the cutting edge and chipping, and the life of the cutting edge is extended. Also, the accuracy of the screw holes is improved. Further, since there is no lateral hole such as a jet hole in a portion to which a cutting force such as a cut-up part with cut-out and a cutting edge is applied, breakage of the tap is eliminated. Furthermore, since fine chips are also discharged by the jetting of oil during the reverse rotation for tap removal, there is no possibility that the chips are caught in the cutting edge during reverse rotation and the tap is damaged or broken unlike the conventional case.

Also, there is no damage to the machined screw hole during reverse rotation.

[Brief description of drawings]

FIG. 1 is a front view in which a part of the embodiment of the present invention is cut away, and FIG.
Figure (a) is a sectional view of the projecting member of Figure 1, (b) is a sectional view of the other embodiment, Figure 3 is a partially cutaway front view of the conventional product, and Figure 4 is another embodiment. The front view which cut a part of the example,
FIG. 5 is an explanatory view showing a cutting edge angle, and FIGS. 6 and 7 are partial sectional views of still another embodiment. 1 …… Cutting edge 2 …… Leading side flank 3 …… Tracking side flank 4 …… Groove 4a …… Groove bottom 5 …… Oil hole 6 …… Handle end face 7 …… Bited blade 7a …… Bited cutting up part 8 …… Blade edge face 9 …… Aperture 9a …… Female thread 10 …… Projection part (projection member) 11 …… Straight hole 12 …… Slant hole (diagonal ejection hole, ejection path) 13 …… Screw 14… … Convex 15 …… Filled metal S …… Tsuruma Line

Claims (3)

[Claims] 1. A shank at a rear end, a cutting blade arranged along a helix line toward a front end, and a plurality of grooves formed in a longitudinal direction. In a tap with an oil hole that is opened and is drilled in the axial center of the main body and the tip of which is closed, at the tip of the bite cut-up portion, the diameter of the cutting edge A tap with an oil hole, characterized in that a non-projecting portion is formed, and the projecting portion is provided with a jetting hole that is in radial communication with the oil hole in the same phase as the groove and that obliquely opens to the handle side. 2. The tap with an oil hole according to claim 1, wherein the projecting portion is formed separately from the tap body, and is attached to an opening at the tip of the chamfered cut-up portion of the oil hole. 3. The tap with an oil hole according to claim 1, wherein the protrusion is formed integrally with the main body.