Tap with oil hole

Abstract

To provide a tap with an oil hole capable of effectively supplying machining oil.SOLUTION: A tap with an oil hole 1 includes a shank 2, a thread portion 4 having a chamfer portion 6 and a complete thread portion 7, a plurality of groove portions 5 provided in a longitudinal direction so as to divide the thread portion 4, a supply hole 10 provided along an axial center from an end surface of the shank 2, and at least one ejection hole 11 branched from the supply hole 10 in a direction orthogonal to the axial center and provided in the plurality of groove portions 5.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a tap with an oil hole.

Background Art

[0002] As a tool for forming a female screw on a workpiece, a tap with an oil hole is known. The tap with an oil hole has a supply hole provided along the axis from the end face of the shank, and a jet hole provided branching from the supply hole. In the tap with an oil hole, the machining oil supplied through the supply hole is jetted into the pilot hole of the workpiece through the jet hole. By allowing the machining oil to enter between the tap with an oil hole and the wall surface of the pilot hole, heat generation during female screw machining can be suppressed, the frictional resistance between the workpiece and the tap with an oil hole can be reduced, and as a result, the tool life of the tap with an oil hole can be extended.

[0003] As a tap with an oil hole, a raising tap described in Patent Document 1 is known. Generally, in a raising tap, for a workpiece in which a pilot hole is machined with a drill or the like, while rotating a screw part, which is a machining part formed in a spiral shape, the tap is gradually bitten into the pilot hole, and a female screw is formed by plastically deforming the pilot hole part. Therefore, since a larger force is required than for forming a female screw by cutting, heat generation and frictional resistance become larger, so appropriate supply of machining oil is important. Also, as a tap with an oil hole, a cutting tap described in Patent Document 2 is known.

[0004] The raising tap described in Patent Document 1 has a supply hole provided along the axis from the end face of the shank, and a jet hole that branches from the supply hole in a direction orthogonal to the axis, that is, outward in the radial direction. The cutting tap described in Patent Document 2 has a supply hole provided along the axis from the end face of the shank, and a jet hole that branches from the supply hole obliquely forward.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, the raised taps described in Patent Documents 1 and 2 do not take into account details such as the arrangement and orientation of the ejection holes in the axial direction, so there is room for improvement in terms of stable internal threading and, consequently, extending the lifespan of the taps.

[0007] The present invention aims to provide a tap with an oil hole that can effectively supply machining oil. [Means for solving the problem]

[0008] According to one aspect of the present invention, an oil-hole tap is provided, comprising a shank, a threaded portion having a cutting portion and a complete thread portion, a plurality of grooves provided longitudinally so as to divide the threaded portion, a supply hole provided along the axis from the end face of the shank, and at least one ejection hole provided in the plurality of grooves, branching from the supply hole in a direction perpendicular to the axis, wherein the at least one ejection hole is arranged along the thread of the complete thread portion.

[0009] It is preferable that the at least one ejection hole is located along the first perfect peak of the perfect peak. It is preferable that the at least one ejection hole includes at least two ejection holes, and at least one of the at least two ejection holes is not located along the first perfect peak. It is preferable that the at least two ejection holes are located within a range of one pitch in the front-rear direction from the first perfect peak. [Effects of the Invention]

[0010] According to aspects of the present invention, a common effect is to provide a tap with an oil hole that can effectively supply machining oil. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a perspective view of a tap with an oil hole according to an embodiment of the present invention. [Figure 2] Figure 2 is a side cross-sectional view of a tap with an oil hole. [Figure 3] Figure 3 is a front view of a tap with an oil hole. [Figure 4] Figure 4 is an enlarged side view of the machined section of the tap with an oil hole. [Figure 5] Figure 5 is another enlarged side view of the machined section of the tap with oil holes. [Figure 6] Figure 6 is a surface photograph of a raised tap after machining using a raised tap according to an embodiment of the present invention. [Figure 7] Figure 7 is a surface photograph of a raised tap after machining using a raised tap according to a comparative example. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below with reference to the drawings. Throughout all drawings, corresponding components are denoted by the same reference numerals.

[0013] Figure 1 is a perspective view of an oil-hole tap 1 according to an embodiment of the present invention, Figure 2 is a side view of the oil-hole tap 1, Figure 3 is a front view of the oil-hole tap 1, and Figure 4 is an enlarged side view of the machined portion 3 of the oil-hole tap 1. The oil-hole tap 1 according to the illustrated embodiment of the present invention is a build-up tap, but it may also be a cutting tap.

[0014] The oil-hole tap 1 has a shank 2 and a machining section 3. The oil-hole tap 1 is attached to the spindle of a machining tool by the shank 2 being gripped by a chuck. In this specification, the machining section 3 side of the oil-hole tap 1 is defined as the "front" side, and the side opposite the machining section 3 is defined as the "rear" side.

[0015] The machining section 3 has a threaded portion 4 formed in a helical shape and a plurality of groove portions 5 provided in the longitudinal direction so as to divide the threaded portion 4. Each of the groove portions 5 of the shaft number is parallel to the axis of the tap 1 with an oil hole. The plurality of groove portions 5 are, for example, eight groove portions 5, but may be other numbers such as two or three groove portions 5. The plurality of groove portions 5 are arranged at equal intervals along the circumferential direction.

[0016] The threaded portion 4 has a biting portion 6 and a complete thread portion 7 continuously arranged behind the biting portion 6. The biting portion 6 is formed in a tapered shape with a thin tip and serves as a call-in for the tap 1 with an oil hole to enter the pilot hole of the workpiece machined with a drill or the like. That is, the outer diameter of the thread at the tip of the biting portion 6 is formed smaller than the inner diameter of the pilot hole. The outer diameter and the effective diameter of the thread of the biting portion 6 gradually increase along the lead from the tip side and are formed to be the valley diameter of the specified fine thread. The length of the biting portion 6 is 2 to 4 threads. In the tap 1 with an oil hole, when the biting portion 6 is screwed into the pilot hole, the metal structure of the pilot hole is gradually crushed and plastically deformed, and the inner surface of the pilot hole is raised to form a fine thread.

[0017] As shown in FIG. 4, the thread located at the tip of the complete thread portion 7 adjacent to the biting portion 6 is referred to as the first complete thread 71, and the thread adjacent to the first complete thread 71 is referred to as the second complete thread 72. Further, the thread located at the rear end of the biting portion 6 adjacent to the first complete thread 71 of the complete thread portion 7 is referred to as the final biting thread 61.

[0018] In the tapping chuck 1 with oil holes, a supply hole 10 is provided from the end face of the shank 2 along the axis up to the inside of the thread portion 4. From the supply hole 10, a plurality of ejection holes 11 are provided, branching in a direction orthogonal to the axis, that is, radially outward. The openings of each of the plurality of ejection holes 11 are provided in the groove portion 5. The machining oil supplied from the machine tool to which the tapping chuck 1 with oil holes is attached is supplied into the supply hole 10 from the end face of the shank 2 and ejected in a direction orthogonal to the axis through the ejection holes 11. The plurality of ejection holes 11 are, for example, eight ejection holes 11, and are arranged in the corresponding groove portion 5, but may be at least one, for example, two or four or other numbers of ejection holes 11. The plurality of ejection holes 11 are preferably arranged symmetrically with respect to the axis of the tapping chuck 1 with oil holes in order to balance the ejection of the machining oil.

[0019] The plurality of ejection holes 11 are arranged along the thread of one lead of the full thread portion 7, specifically, along the first full thread 71. Specifically, although the thread is formed in a spiral shape and is divided by the groove portion 5, each of the eight ejection holes 11 is arranged in the groove portion 5 of the corresponding portion in the divided first full thread 71. Therefore, the adjacent ejection holes 11 are arranged at positions offset from each other in the axial direction along the thread.

[0020] Referring to FIG. 3, among the eight ejection holes 11 provided in the tapping chuck 1 with oil holes, the ejection hole 11 arranged most forward, that is, the ejection hole 11 arranged at the most distal end in the first full thread 71, is designated as the first ejection hole 11A, and the ejection holes 11 arranged at positions shifted 90 degrees, 180 degrees, and 270 degrees in the rotation direction from the first ejection hole 11A are respectively regarded as the second ejection hole 11B, the third ejection hole 11C, and the fourth ejection hole 11D.

[0021] Figure 5 is another enlarged side view of the machined portion 3 of the oil-hole tap 1. Referring to Figure 5 in addition to Figure 3, Figure 5(A) is a side view of the machined portion 3 facing the first ejection hole 11A, Figure 5(B) is a side view of the machined portion 3 facing the second ejection hole 11B, Figure 5(C) is a side view of the machined portion 3 facing the third ejection hole 11C, and Figure 5(D) is a side view of the machined portion 3 facing the fourth ejection hole 11D. In Figures 5(A) to 5(D), a reference line R is drawn from the tip of the oil-hole tap 1 across the machined portion 3 at equal positions. In Figure 5(A), the reference line R indicates the axial position of the starting point of the first complete thread 71. As shown in Figure 5(A), the reference line R passes through approximately the center of the first ejection hole 11A. As shown in Figure 5(B), the second nozzle 11B is located rotated 90 degrees from the position of the first nozzle 11A, and is therefore shifted backward relative to the first nozzle 11A by a length of 1 / 4 of a pitch in the axial direction. Similarly, as shown in Figure 5(C), the third nozzle 11C is located rotated 180 degrees from the position of the first nozzle 11A, and is therefore shifted backward relative to the first nozzle 11A by a length of 1 / 2 of a pitch in the axial direction. As shown in Figure 5(D), the fourth nozzle 11D is located rotated 270 degrees from the position of the first nozzle 11A, and is therefore shifted backward relative to the first nozzle 11A by a length of 3 / 4 of a pitch in the axial direction.

[0022] With the oil-hole tap 1, machining oil is ejected through the ejection holes 11 in a direction perpendicular to the axis. The machining oil ejected from the ejection holes 11 collides with the inner wall of the pilot hole and is dispersed in the front-rear direction. As a result, it becomes possible to supply machining oil more evenly within the pilot hole during internal thread machining with the oil-hole tap 1. In detail, since the ejection holes 11 are positioned along the first complete thread 71, the ejected machining oil collides with the root of the internal thread being formed by the first complete thread 71 and flows along the flanks, which are the slopes of the threads being formed before and after it. As a result, it becomes possible to supply machining oil evenly in the front-rear direction with respect to the first complete thread 71, that is, in both directions of the engagement portion 6 and the complete thread portion 7.

[0023] The first perfect thread 71 of the perfect thread section 7 is the part that transitions from the tapered engagement section 6, and therefore the greatest force is applied to it during internal thread machining. In particular, the first perfect thread 71 has the largest outer diameter in the thread section 4, that is, in the perfect thread section 7, albeit slightly. Therefore, during internal thread machining, the frictional resistance applied to the first perfect thread 71, especially the flank surface of the first perfect thread 71 on the engagement section 6 side, is the greatest. Accordingly, by spraying machining oil from the ejection holes 11 arranged along the first perfect thread 71 and supplying machining oil in the front-rear direction of the first perfect thread 71, stable internal thread machining can be achieved, the effect of reducing frictional resistance and heat generation can be maximized, and the effect of extending tool life can be maximized.

[0024] Figure 6 is a surface photograph of a raised tap after processing using the raised tap 100 according to an embodiment of the present invention, and Figure 7 is a surface photograph of a raised tap after processing using the raised tap 200 according to a comparative example. Figures 6 and 7 are photographs of the raised tap viewed from the front at an oblique angle above.

[0025] The ridge tap 100 shown in Figure 6 has a threaded portion 104 and a groove 105 provided to separate the threaded portion 104. The threaded portion 104 has a first complete crest 171 and a second complete crest 172 in the complete crest section and a final cutting crest 161 in the cutting section. Within the groove 105, a ejection hole 111 is arranged along the first complete crest 171. Similarly, the ridge tap 200 shown in Figure 7 has a threaded portion 204 and a groove 205 provided to separate the threaded portion 204. The threaded portion 204 has a first complete crest 271 and a second complete crest 272 in the complete crest section and a final cutting crest 261 in the cutting section. Within the groove 205 forward of the first complete crest 271, an ejection hole 211 is arranged. The ejection hole 211 is an ejection hole that branches off from the supply hole in a direction perpendicular to the axis. In other words, the raised tap 100 and the raised tap 200 differ only in the arrangement of the ejection holes.

[0026] Referring to the surface photograph of the machined raised tap 100 shown in Figure 6, no noticeable scratches or damage are visible on the surface of the threaded portion 104. Therefore, it can be said that the machining oil was effectively supplied with the raised tap 100. On the other hand, referring to the surface photograph of the machined raised tap 200 shown in Figure 7, abrasion marks F are present on the flank surfaces of the first complete thread 271 and the second complete thread 272. Therefore, as mentioned above, with the raised tap 200, the machining oil was not properly supplied to the first complete thread 271, which has particularly high frictional resistance, and the surface of the raised tap 200 was damaged by friction and heat generation.

[0027] Based on the above, according to the embodiments of the present invention, it is possible to provide a tap with an oil hole 1 that can effectively supply machining oil. Since the machining oil is ejected radially outward from the tap with an oil hole 1, it can be used whether the pilot hole of the workpiece is a through hole or a blind hole.

[0028] In the oil-hole tap 1, it is sufficient to have at least one ejection hole 11. Preferably, at least one ejection hole 11 is positioned along the first complete thread 71, but it may also be positioned along the threads of other complete thread sections 7. By positioning the ejection hole 11 along the threads of the complete thread sections 7, as described above, the ejected machining oil collides with the valley bottom of the internal thread being formed. As a result, it flows along the flank surfaces, which are the slopes of the internal thread being formed before and after the collision, making it possible to supply the machining oil evenly.

[0029] If at least two ejection holes 11 are provided, at least one of the at least two ejection holes 11 does not have to be positioned along the first perfect peak 71. In this case, it is preferable that at least two ejection holes 11 are positioned within a range of one pitch in the front-rear direction from the first perfect peak 71, that is, between the final cut peak 61 and the second perfect peak 72. Specifically, at least two ejection holes 11 may be positioned only between the final cut peak 61 and the first perfect peak 71, or only between the first perfect peak 71 and the second perfect peak 72. By positioning the ejection holes 11 at least between the final cut peak 61 and the second perfect peak 72, it becomes possible to supply machining oil to the first perfect peak 71, which is most likely to be damaged. [Explanation of Symbols]

[0030] 1 tap 2. Shank 3 Processing section 4. Threaded section 5 grooves 6. Meal portion 7 Complete Mountain Club 10 Supply hole 11 Spout hole 61. The final mountain with meals included. 71 1st complete mountain 72 Second complete mountain

Claims

1. Shank and, A threaded portion having a cutting portion and a complete thread portion, Multiple grooves are provided in the longitudinal direction to divide the threaded portion, A supply hole provided along the axis from the end face of the shank, It comprises a plurality of ejection holes provided within the plurality of grooves, branching from the supply hole in a direction perpendicular to the axis, An oil-hole tap characterized in that at least one of the plurality of ejection holes is arranged along the threads of the complete thread portion.

2. The oil-hole tap according to claim 1, wherein the at least one ejection hole is arranged along the first perfect crest of the perfect crest, and the first perfect crest is a thread located at the tip of the perfect crest adjacent to the cutting portion.

3. The oil-hole tap according to claim 2, wherein at least one of the plurality of ejection holes is not arranged along the first complete peak.

4. The oil-hole tap according to claim 3, wherein at least two of the plurality of ejection holes are arranged within a range of one pitch in the front-rear direction from the first complete peak.

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