EP3213895B1 - Drill with cylindrical head - Google Patents

Description

The invention initially relates to a cylinder head drill, as it is further outlined in the preamble of claim 1.

The starting point for the invention is therefore a cylinder head drill with a clamping shaft and with a drill head which comprises a centering tip and an outer jacket wall with at least substantially cylindrical outer surface, and wherein between the centering tip and the outer surface at least one main cutting edge is arranged substantially extends radially, wherein in the drill head at least one adjoining the free surface of the main cutting, circumferentially open, the drill head obliquely penetrating and the shell wall interrupting chip channel is arranged, and wherein the outer surface is provided with a plurality of narrow grooves. Such a cylinder head drill is from the US 4,134,706 known. A cylinder head drill provided with two main cutting edges is known, firstly by the applicant's patent DE 197 02 423 B4 and second, but without any grooves, by Applicant's patent DE 41 15 030 C1 ,

In the cited documents, the local problem situation in cylinder head drills is explained in detail, so that a detailed repetition can be dispensed with here. Especially in the first mentioned document, DE 197 02 423 B4 , is, in short, mainly sought to create a cylinder head drill, which heats up as little as possible when working. As a solution, inter alia, it is proposed that the outer surface of the otherwise smooth-walled jacket wall is interrupted by so-called radial bulges, ie grooves. As all embodiments show, these grooves are relatively wide and either run exactly axially or obliquely axially, so that they can serve to form a plurality of precutting, which then together form a drill collar.

Even narrow, external grooves in drills of a different design are already known from the prior art. So are by the FR 1 274 316 A or WO 1998 35 777 A1 with spiral drills so-called round bevels or guide bevels known. These round bevels, grooves or grooves serve for better concentricity, for better or additional cutting action on the spiral edges or to indicate the drilling depth.

In contrast to the relatively long and slender twist drills or long hole drills, the drill diameter is a multiple of the shell height for a relatively thick and short cylinder head drill. With the cylinder head drill, the centering tip and the outer lateral surface already ensure a straight bore of a relatively large bore diameter. From the WO 1998 35 777 A1 on page 3 below and page 4 above, the person skilled in the art recognizes that the local grooved drill bit is preferably intended for drilling long holes through a workpiece, but not for the formation of - usually relatively short - holes, in particular blind holes. The latter, however, is the typical task of a cylinder head drill.

But even with wood drills similar design grooves are already known, which rotate on the outer surface: The US 6,354,773 B1 shows a wood drill, which has at its two narrow and wing-like outer surfaces a plurality of circumferential grooves.

The US 4 134 706 A shows a wood drill bit similar construction with two approximately radial main cutting edges and two Vorschneiden. On its outer surface, it has some helical circumferential grooves.

The US 3,180,379 A. shows a slot drill with a single radial cutting edge, which is also provided on its outside with helically encircling grooves.

In particular, the invention treated in the first-mentioned invention has proven to be excellent. The invention aims to build on this.

Based on this prior art, the invention is based on the desire to develop the cylinder head drill so that when drilling inevitable even occurring on the relatively large shell wall process heat is significantly reduced to improve the cutting performance both quantitatively and qualitatively.

Based on a cylinder head drill of the type mentioned is therefore proposed that at least two grooves intersect.

A particularly prominent pattern results on the outer surface of the drill head when a plurality of grooves or helical and with opposite slope so that they intersect. Their slope may preferably be the same, but also different.

In the first-mentioned prior art, the recesses mentioned there bulges are relatively wide and while also serve to loosen the outer surface, but in particular to form a drill collar with multiple precutting. For this they either run axially or they have a relatively large pitch, namely significantly larger than the diameter of the cylinder head drill. The inventive, namely intersecting grooves initially serve only the purpose of virtually crumbling the outer surface as much as possible in order to effectively increase this.

Due to the formation of intersecting relatively narrow - and possibly also deep - grooves, a plurality of grooves can be introduced into the outer surface. As a result, the actual outer surface is on the one hand significantly increased by the additional side surfaces of the grooves, on the other hand, the stability of the shell wall, their leadership and thus their leadership function remain fully preserved; because the shell wall is only slightly weakened by the narrow grooves. By now virtually enlarged inward outer surface, the outer contact surface is reduced with the material wall to be drilled and the frictional heat generated on the shell wall can better be given to the air surrounding the outer surface, namely in the grooves.

The invention can thus also with a cylinder head drill simple or older type, as it is often and described for example in the second-mentioned document, are used with advantage.

The feature "narrow" for the groove-shaped grooves is here variable and to be seen in relation to the diameter of the cylinder head drill. In particular, it can be provided that the width of a groove, depending on the outer diameter, 0.5 mm to 2.0 mm: the larger the diameter of the drill, the wider - and possibly deeper - may be the groove.

The invention initially requires only a cylinder head drill with a jacket wall and a single main cutting edge. However, it is preferably used in a cylinder head drill with two to four main cutting edges.

However, it can also be provided within the scope of the invention that at least one groove or groove preferably runs slightly helically. Slightly helical should mean here that the slope is relatively low, which means that the slope is at least as small as possible to the diameter of the drill, which will be discussed in more detail below.

In this case, such a groove or groove can run clockwise. Then, when turning the drill, an axial moment in the direction of the centering tip, quasi a pull-in torque is generated.

It can also be provided that at least two grooves or grooves extend helically and parallel to one another. Thus, the aforementioned positive effect can be reinforced.

It has been found that it is advantageous for the purposes of the invention if at least half of the outer surface is interrupted by the grooves or grooves. Because then results both an increased heat dissipation and a good leadership.

The cross section of the grooves or grooves may be formed in different ways, in particular part-circular, semicircular, V-shaped or U-shaped. Again, by choosing or combining different in shape and / or size cross-sections a special pattern on the cylinder head drill can be generated, which can also serve to identify the manufacturer or supplier.

All the above embodiments can be realized even with a relatively simple cylinder head drill, namely, if a smooth outer surface is available, such. B. in the second above-mentioned document, DE 197 02 423 B4 , However, the invention is used particularly advantageously in a cylinder head drill, which, as in the first-mentioned document, DE 41 15 030 C1 , is trained. Such a cylinder head drill is thus designed such that the outer surface is additionally interrupted by axially or obliquely axially extending and in relation to the grooves wider grooves, so-called. Recesses or bulges, to form precut in the form of a drill collar. Here, the reduction of the outer surface involved in the friction is extremely reduced, and the removal of the heat generated is significantly accelerated.

It has been found that the dimensions of the grooves in relation to the other dimensions of the cylinder head drill play an essential role. Thus, at a low pitch, it is suggested that the ratio of outer diameter of the cylinder head bit to pitch of a groove be 8 to 30 to 1, depending on the size of the diameter.

The pitch of a groove can be in particular 1 to 3.5 mm. Examples: For a diameter of 8 mm the pitch is 1 mm, for a diameter of 30 mm 2 mm and for a diameter of 60 mm 3.5 mm.

On the one hand, the depth of the grooves or grooves increases the outer surface in a positive manner, on the other hand, it must not unduly weaken the shell wall. The larger the diameter of the cylinder head drill, the deeper can be a groove or groove. It has proved to be very favorable if the depth of a groove, depending on the diameter, is preferably 0.1 mm to 0.65 mm. Preferably, the ratio of outer diameter of the cylinder head drill to the depth of a groove should be 80 to 160 to 1. Moreover, the expert will always refrain from a greater depth of a groove or groove when he sees the stability of the cylinder drill threatened by excessive removal of material.

Depending on the design of the geometry of the drill head thus grooves with different width and / or depth can be introduced: For example, in places with more "meat" in the shell wall, as in her foot, to the clamping shaft out, and in particular at a relatively large Cylinder head drill with a relatively thick shell wall, as over 40 mm or even 100 mm in diameter, a deeper and possibly wider groove can be introduced without weakening the drill head in an excessive manner.

Finally, in order to further improve the cooling of the drill head, it is proposed that a plurality of axial grooves and / or at least one spiral groove be arranged on the part-annular end surface of the drill head, which adjoins the previously considered outer surface in the direction of the clamping shaft. Again, the relatively narrow width and possible depth of the groove or grooves of the already described conditions dependent and classified by the expert.

The invention provides the person skilled in a wealth of possibilities to the hand, a cylinder head drill quite simple or even of the aforementioned special design, namely with drill collar, so that the total on the drill head and especially on the shell wall during drilling inevitably resulting heat as quickly as possible and very effectively dissipated. The design according to the invention therefore leads to a reduction in the development of heat, to a longer service life of the cylinder head drill and to an improved quality of the produced Drilling. In addition, there is the possibility to give the cylinder head drill a striking, independent and handsome exterior.

• Fig. 1 zeigt eine erste Ausführungsform als Weiterbildung des Zylinderkopfbohrers nach der DE 197 02 423 B4 mit einer Rille in derselben Ebene und mit einer wendelförmigen Rille, wobei acht schräg-axiale gerundete Nuten nahezu alle Rillen schneiden.
• Fig. 1a zeigt den Zylinderkopfbohrer nach Fig. 1 in einer anderen Perspektive.
• Fig. 1b zeigt den Zylinderkopfbohrer nach Fig. 1a in der Seitenansicht.
• Fig. 1c zeigt den Zylinderkopfbohrer nach Fig. 1a in Stirnansicht.
• Fig. 2 zeigt eine zweite Ausführungsform, ähnlich der Fig. 1, mit einer Rille in derselben Ebene und mit sechs parallelen, wendelförmigen Rillen, die acht schräg-axiale Nuten schneiden.
• Fig. 3 zeigt eine dritte Ausführungsform, ähnlich der Fig. 1, mit einer Rille in derselben Ebene und mit acht rechtsdrehenden Rillen, die acht linksdrehende Rillen kreuzen.
• Fig. 4 zeigt eine vierte Ausführungsform, als Weiterbildung des Zylinderkopfbohrers nach DE 41 15 030 C1 , mit sich kreuzenden Rillen und entsprechend der Fig. 3.
• Fig. 5 zeigt eine fünfte Ausführungsform, ähnlich der Fig. 1, mit einer Rille in derselben Ebene und mit acht rechtsdrehenden Rillen, wobei die Rillen die acht Nuten schneiden.
• Fig. 6 zeigt eine sechste Ausführungsform, ähnlich der Fig. 4, mit sich kreuzenden Rillen, ähnlich wie in Fig. 5.
• Fig. 7 zeigt einen Bohrkopf eines weiteren Zylinderkopfbohrers, ähnlich wie Fig. 5, jedoch mit weiteren Rillen im Fußbereich.

In the drawings, embodiments of the invention are shown, which will now be described in more detail.

• Fig. 1 shows a first embodiment as a development of the cylinder head drill according to the DE 197 02 423 B4 with a groove in the same plane and with a helical groove, with eight oblique-axial rounded grooves intersecting almost all the grooves.
• Fig. 1a shows the cylinder head drill Fig. 1 in a different perspective.
• Fig. 1b shows the cylinder head drill Fig. 1a in the side view.
• Fig. 1c shows the cylinder head drill Fig. 1a in front view.
• Fig. 2 shows a second embodiment, similar to the Fig. 1 , with a groove in the same plane and with six parallel helical grooves intersecting eight oblique-axial grooves.
• Fig. 3 shows a third embodiment, similar to Fig. 1 with a groove in the same plane and eight right-hand grooves that intersect eight left-handed grooves.
• Fig. 4 shows a fourth embodiment, as a further development of the cylinder head drill DE 41 15 030 C1 , with intersecting grooves and according to the Fig. 3 ,
• Fig. 5 shows a fifth embodiment, similar to Fig. 1 with one groove in the same plane and eight right-hand grooves, with the grooves intersecting the eight grooves.
• Fig. 6 shows a sixth embodiment, similar to Fig. 4 , with intersecting grooves, similar to in Fig. 5 ,
• Fig. 7 shows a drill head of another cylinder head drill, similar to Fig. 5 , but with more grooves in the foot area.

The in the Fig. 1 to 1c shown cylinder head drill 101 is composed of a clamping shaft 102 and a substantially cup-shaped head 103 in principle, which includes a slightly projecting in the drill axis XX centering tip 104 and an outer shell wall 105 having a substantially cylindrical outer surface 106. Between the centering tip 104 and the outer surface 106 extend approximately radially two main cutting edges 107. In the drill head 103 close to each main cutting edge 107 two open spaces 108, which in turn pass into two chip channels 109.

The chip channels 109 penetrate the drill head 103 obliquely from the main cutting edges 107, except for the adjoining round part of the clamping shaft 102. In this way, the chip channels 109 interrupt the jacket wall 105 into the foot part 110, so that both the jacket wall 105 and the drill head 103 so that its outer surface 106 - as well as the foot part 110 are divided into two sections.

On the outer surface 106 a total of eight obliquely axially extending and rounded in the base grooves 111 are introduced, which are referred to in the art as bulges and serve to form Vorschneiden 112, which together form a split drill collar 113. The width BN of the grooves 111 is here on average about 6 mm, the depth TN varies here between 0 - in the foot - and ca.1 mm in the area of Vorschneiden 112. The diameter D of the cylinder head drill 101 is here 50 mm. The number of precutting 112 can vary and in particular is adapted to the respective diameter of the cylinder head drill. In addition to the oblique grooves 111, narrow grooves 114 are introduced on the split outer surface 106, which run tangentially around the outer surface 106 or coaxial with the drill axis X - X and thereby intersect the grooves 111. The grooves 114 here consist of a first upper groove 114.1, in the same axial plane and a groove 114.2, which runs down in a spiral and clockwise so that it surrounds the outer surface 106 several times.

The width B of a groove 114, 114.1 and 114.2 is here, at this diameter D, about 1.6 mm, the depth T about 0.6 mm and the slope S about 3.5 mm. The cross-section Q is part-circular with a radius R of about 1.2 mm. Due to the very large fracture of the outer surface 106 - namely by the oblique-axial grooves 111 on the one hand and by the grooves 111 crossing tangential grooves 114 on the other hand - the original outer surface is reduced to less than half, but the effective outer surface through the additional side walls of the Grooves 111 and grooves 114 significantly increased.

The Fig. 1a to 1c show the cylinder head drill 101 after Fig. 1 in other views to better illustrate its spatial structure.

In Fig. 2 is a cylinder head drill 101b shown as he Fig. 1 underlying. Here, although the first upper groove 114.1 also extends in the same axial plane, below, however, six parallel, right-handed, helical grooves 114.3 are arranged, which intersect the grooves 111.

In Fig. 3 is a cylinder head drill 101d shown as he Fig. 1 underlying. Here, the first uppermost groove 114.1 extends in the same axial plane, below which, however, eight parallel and slightly spaced, right-handed helical grooves 114.4 are arranged, which intersect with eight correspondingly formed and arranged, but left-handed helical grooves 114.4. The slope S is here formed slightly larger than in the preceding embodiments with a direction of rotation.

In Fig. 4 a cylinder head drill 101e is shown, which is essentially the Fig. 1 corresponds, but has the simpler form of a so-called. Forstner drill: Here is no drill collar with pre-cutting exists, since the grooves 111 was omitted here, as in principle the DE 41 15 030 C1 shows how he is the Fig. 2 underlying. Here, the grooves 114.1 and 114.4 extend as to the Fig. 3 explained. It will especially the diamond pattern resulting crossing course of the grooves 114.4 clearly.

In Fig. 5 is a cylinder head drill 101f shown as he Fig. 1 underlying. Here, the first uppermost groove 114.1 extends in the same axial plane, but below it eight grooves 114.5 are arranged, which run parallel to each other and at a slight distance from each other and form clockwise helices. All grooves 114.1 and 114.5 intersect the eight grooves 111.

In Fig. 6 is a cylinder head drill 101g shown as he Fig. 4 underlying. The grooves 114.1 and 114.5 extend as to the Fig. 5 explained and partially intersect.

In Fig. 7 a drill head 113 of a further cylinder head drill 101h according to the invention is shown, which is approximately according to the structure Fig. 1 equivalent. The grooves 114 intersect the grooves 111. Here, the foot surface 115, so the two-part surface between the outer surface 106 and the round part of the clamping shaft 102, also provided with grooves 116. In this case, it is also possible for any rounding 115 lying between the outer surface 106 and the angularly adjoining base surface 115 to be provided with grooves 116.

These grooves 116 may be either concentric with the drill axis X - X extending grooves or consist of one or more spirally extending grooves. Again, these grooves 116 may correspond or resemble the described grooves 114 on the outer surface 106 in shape and extent.

If the thickness of wall 105 or foot 110 - which also depends on the diameter of the drill head 113 - allows, these grooves 116 may also be formed much deeper and / or wider. Especially since the foot surface 115 has no guiding function as the outer surface 106, but here also serves to dissipate the frictional heat generated on the casing wall 105 and the drill collar 113.

LIST OF REFERENCE NUMBERS

101

Cylinder head drills

101b

Cylinder head drills

101d

Cylinder head drills

101e

Cylinder head drills

101f

Cylinder head drills

101g

Cylinder head drills

101h

Cylinder head drills

102

clamping

103

wellhead

104

centering

105

shell wall

106

outer surface

107

main cutting edge

108

open space

109

chip channel

110

footboard

111

groove

112

Vorschneide

113

drill collar

114

groove

114.1

groove

114.2

groove

114.3

groove

114.4

groove

114.5

groove

115

foot surface

116

groove

B

groove width

BN

groove width

D

diameter

S

pitch

T

groove depth

TN

groove depth

X X

drill axis

Claims (8)

1. Cylinder-head drill bit (101d to 101g) having a clamping shank (102) and having a drill head (103), which has a centring point (104) and an outer lateral wall (105) with an at least substantially cylindrical outer surface (106), and in which, between the centring point (104) and the outer surface (106), at least one main cutting edge (107) is arranged, which extends substantially radially, wherein at least one chip passage (109) that adjoins the flank (108) of the main cutting edge (107), is open towards the circumference, passes obliquely through the drill head (103) and interrupts the lateral wall (105) is arranged in the drill head (103), and wherein the outer surface (106) is provided with a multiplicity of narrow flutes (114.1, 114.4, 114.5), characterized in that at least two flutes (114.1, 114.4, 114.5) intersect.
2. Cylinder-head drill bit (101 to 101h) according to Claim 1 or according to the preamble of Claim 1, in which the outer surface (106) is interrupted by a plurality of grooves (111) that extend axially or obliquely axially and are wider than the flutes (114 to 114.5), in order to form roughing edges (112) in the form of a core drill bit (113), characterized in that the width (B) and/or the depth (T) of two or more flutes (114 to 114.5) is or are configured to be different.
3. Cylinder-head drill bit (101) according to Claim 1 or 2, characterized in that two to four main cutting edges (107) are arranged.
4. Cylinder-head drill bit (101) according to one of Claims 1 to 3, characterized in that at least one flute (114.1) extends in the same axial plane.
5. Cylinder-head drill bit (101) according to one of Claims 1 to 4, characterized in that at least one flute (114.2) extends in a helical manner.
6. Cylinder-head drill bit (101b, 101c) according to Claim 5, characterized in that at least two flutes (114.3) extend in a helical manner and parallel to one another.
7. Cylinder-head drill bit (101) according to one of Claims 1 to 6, characterized in that at least half of the outer surface (106) is interrupted by the grooves (111) and flutes (114, 114.1, 114.2).
8. Cylinder-head drill bit (101h) according to one of Claims 1 to 7, characterized in that a plurality of axial flutes (116) that extend coaxially with the drill-bit axis (X-X) and/or at least one axial flute (116) that extends in a spiral manner with respect to the drill-bit axis (X-X) is or are arranged on the root face (115) of the drill head (103) .

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