阅读说明：本技术 组合工具以及用于此类钻孔/倒角工具的钻头 (Combination tool and drill bit for such a drilling/chamfering tool ) 是由 M.保罗 B.埃克尔 H.R.考珀 于 2020-03-13 设计创作，主要内容包括：一种组合工具(2),具体而言是钻孔/倒角工具,其包括在纵向方向(4)上延伸的钻头(6)与夹紧套筒(8),所述夹紧套筒被设计成接收所述钻头(6)且以可变长度紧固所述钻头(6),所述夹紧套筒还具有用于切削刀片(12)的保持座(38)。所述钻头(6)包括设置有凹槽(14)的切削区域(22),其中所述凹槽(14)成螺旋形延伸,且钻头背面(18)形成于两个凹槽(14)之间。所述钻头背面(18)中的至少一个部分地平坦化以形成用于所述切削刀片(12)的调节表面(16),其中所述调节表面(16)成螺旋形延伸。因此,有可能独立于扭转角(γ)进行在较大长度范围内的长度调节。(Combination tool (2), in particular drilling/chamfering tool, comprising a drill bit (6) extending in a longitudinal direction (4) and a clamping sleeve (8) designed to receive the drill bit (6) and to tighten the drill bit (6) with a variable length, the clamping sleeve further having a retaining seat (38) for a cutting insert (12). The drill bit (6) comprises a cutting area (22) provided with grooves (14), wherein the grooves (14) extend helically and a bit back face (18) is formed between two grooves (14). At least one of the bit backs (18) is partially flattened to form an adjustment surface (16) for the cutting insert (12), wherein the adjustment surface (16) extends helically. Thus, it is possible to perform length adjustment over a wide length range independently of the torsion angle (γ).)

1. Combination tool (2), in particular a drilling/chamfering tool, with a drill bit (6) extending in a longitudinal direction along a rotational axis (R) and with a clamping sleeve (8) which is designed to receive the drill bit (6) and to fasten the drill bit (6) in variable lengths, which also has a retaining seat (38) for a cutting insert (12), wherein the drill bit (6) has a cutting region (22) provided with a groove (14) and the groove (14) extends helically at a torsion angle γ, wherein a helically extending drill back face (18) with a curved peripheral surface (26) is formed between two grooves (14), wherein at least one of the drill back faces (18) is partially flattened to form an adjustment surface (16),

it is characterized in that the preparation method is characterized in that,

the adjustment surface (16) extends helically.

2. A cluster tool (2) according to claim 1,

it is characterized in that the preparation method is characterized in that,

the adjustment surface (16) extends at the same twist angle (γ) as the recess (14).

3. A cluster tool (2) according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the adjustment surface (16) tapers into one of the grooves (14).

4. Combination tool (2) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the bit back face (18) covers a predetermined angular range (β) between the grooves (14), wherein the adjustment surface (16) covers at least one quarter (β 1) of the predetermined angular range.

5. Combination tool (2) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the adjustment surface (16) encloses an angle (a) with the curved peripheral surface (26), in particular in the range of 80 ° to 160 °, in particular 115 ° to 145 °, when viewed in cross section.

6. Combination tool (2) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the adjustment surface (16) extends in the longitudinal direction (4) and comprises a front end, wherein the adjustment surface (16) transitions via a step into the curved peripheral surface (26).

7. Combination tool (2) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the adjustment surface (16) extends in the longitudinal direction (4) over a length that is a multiple of a nominal diameter of the drill bit (6).

8. Combination tool (2) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the twist angle (γ) is in the range of more than 5 °, in particular >20 °, and preferably in the range of 20 ° to 45 °.

9. Combination tool (2) according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the drill bit (6) and the clamping sleeve (8) are positively guided together via a guide element (29) such that in a longitudinal movement of the clamping sleeve (8) in the longitudinal direction (4), the clamping sleeve (8) automatically rotates about the rotational axis (R) as a function of the twisting of the groove (14).

10. A cluster tool (2) according to claim 9,

it is characterized in that the preparation method is characterized in that,

the guide element (29) is formed on one of the drill bit backs (18).

11. A drill bit (6) for a combination tool, in particular for a drilling/chamfering tool, the drill bit (6) comprising a cutting insert (12) provided with grooves (14), wherein the grooves (14) extend helically at a twist angle (γ) and a helically extending bit back face (18) with a curved peripheral surface (26) is formed between two grooves (14), wherein at least one of the bit back faces (18) is partially flattened to form an adjustment surface (14),

it is characterized in that the preparation method is characterized in that,

the adjustment surface (14) extends helically.

Technical Field

The invention relates to a combination tool, in particular a drilling/chamfering tool, having a drill bit extending in a longitudinal direction along a rotational axis and having a clamping sleeve which is designed to receive the drill bit and to fasten the drill bit in variable lengths, the clamping sleeve also having a retaining seat for a cutting insert, wherein the drill bit has a cutting region provided with grooves, and the grooves extend helically at a twist angle, wherein a helically extending drill back face having a curved peripheral surface is formed between two grooves, and at least one of the drill back faces is partially flattened to form a flat adjusting surface for the cutting insert. The invention also relates to such a drill bit for such a combination tool.

Background

In the present invention, the "combination tool" means a combined tool consisting of a drill and additional cutting inserts arranged at the periphery of the drill, such as a chamfering insert (chamferring insert), a countersinking insert (counterboring insert), or a reaming insert (reaming insert), etc. In the combination tool, a length adjustment is provided such that the distance between the drill cutting edge of the drill and the cutting edge of the cutting insert in the longitudinal direction can be variably adjusted for the machining operation. In this case, "adjustable" means in particular an adjustability in the longitudinal direction of at least half the nominal diameter of the drill bit.

Such drilling/chamfering tools and such drill bits can be found in US 8142115B 2. In the tool known from said patent, the adjustment surface extends parallel to the longitudinal direction and allows variable length adjustment and tightening of the drill bit within the clamping sleeve.

Such drilling/chamfering tools are used for drilling and at the same time for forming a chamfer or countersinking a drill hole formed in one working process. For example, the chamfer or countersink region is intended to receive the head of a screw or to receive the head of a rivet.

The variable length adjustment of the clamping sleeve to which the cutting insert is attached allows the same tool to be used for different applications, and in particular for different drilling depths.

In the previously described drilling/chamfering tool, for example, the adjustment surface on the drill bit is used, but not necessarily, for abutting the cutting insert. Due to the flattening, the cutting edge of the cutting insert may be directed further radially towards the center. However, only a limited length of adjustment is possible.

Disclosure of Invention

Continuing from this, the invention is based on the task of specifying a combination tool and a drill bit for such a combination tool, wherein length adjustments are possible within the greatest possible range.

According to the invention, this object is achieved by means of a combination tool, in particular a drilling/chamfering tool, having a drill bit extending in a longitudinal direction along a rotational axis and having a clamping sleeve which is designed to receive the drill bit and to fasten the drill bit in variable lengths. The clamping sleeve has a retaining seat for a cutting insert, such as a chamfering tool. The drill bit comprises a cutting area provided with grooves, wherein the grooves extend helically at a twist angle. Between two adjacent grooves, a helically extending drill back face having a curved peripheral surface is correspondingly formed. At least one, alternatively several or all of the bit backs are partially flattened so that a conditioning surface is formed. The adjustment surface extends helically, i.e. also at a twist angle. This is understood to mean the borderline, i.e. the transverse delimiting line of the surface, extending helically and thus along a helix.

The term "partially" is understood to mean that the planarization extends at least over a sub-area of the length of the back face of the drill bit.

The term "flattened" is generally understood to mean that the distance of (each) point on the adjustment surface to the axis of rotation is smaller than the distance from the back of the bit, in particular from the curved peripheral line of the back of the bit, to the axis of rotation, in particular when viewed in a cross-section perpendicular to the axis of rotation.

The cutting insert has a side surface facing the adjustment surface in the assembled state. This side surface is, for example, an abutment surface of the cutting insert against the adjustment surface in the assembled state. Preferably, the cutting insert, i.e. the gap between this side surface and the adjustment surface, is formed in the assembled state. For precise alignment of the cutting insert, in particular in this case, a defined abutment contour or abutment surface for the cutting insert is formed on the clamping sleeve. This abutment surface on the clamping sleeve preferably extends parallel to the tool longitudinal axis and thus parallel to the axis of rotation. Alternatively, it is aligned at an angle to the axis of rotation.

The side surface of the cutting insert oriented towards the adjustment surface preferably extends parallel to the adjustment surface, when viewed in a cross-section perpendicular to the axis of rotation, and is designed in particular as a planar surface.

The adjustment surface is preferably designed to extend linearly, when viewed also in a cross section perpendicular to the axis of rotation. Alternatively, it is curved.

The cutting insert is generally movable along the adjustment surface. In a preferred embodiment, the side or abutment surface of the cutting insert is designed as a plane surface, which, for example, in the assembled state extends parallel to and abuts against the adjustment surface.

According to the invention, the task is additionally achieved by means of a drill bit for a combination tool, in particular for a drilling/chamfering tool, comprising a cutting insert provided with grooves, wherein the grooves extend helically at a twisting angle, and a helically extending bit back face having a curved peripheral surface is formed between two grooves, wherein at least one of the bit back faces is partially flattened to form a helically extending flat conditioning surface.

The twist angle of the groove is an angle different from zero. Typically, the twist angle is >5 °, and further preferably >10 °, and typically ranges between 25 ° and 45 °.

A particular advantage of the helically running adjusting surface is that the adjusting surface can be designed substantially longer overall when viewed in the longitudinal direction, compared to an adjusting surface oriented parallel to the longitudinal direction, so that the greatest possible length range is created over which length adjustment is possible. This provides the advantage, inter alia, that a relatively large, even conventional twist angle can be used for the recess and at the same time still a sufficiently large axial adjustment range is produced.

In designs known in the prior art, the twist angle limits the adjustment range. For a sufficient adjustment range, a special very low torsion angle of the groove is required in the known design.

Suitably, the adjustment surface is arranged to extend at the same twist angle as the groove. Thus, the adjustment surface extends practically parallel to the groove. Specifically, the adjustment surface has a constant width over its entire length. Alternatively, the adjustment surface has a different twist angle than the groove. For example, the conditioning surface is introduced by a subsequent grinding process.

In a preferred embodiment, the adjustment surface tapers into one of the grooves. Specifically, it tapers into the leading groove. The leading groove is the groove that is arranged before the bit back face in the intended direction of rotation during operation. The adjustment surface thus has a radially inner end, which tapers into the leading groove, as viewed in the circumferential direction. Thus, the cutting insert and its cutting edge may also extend generally to some extent into the recess.

As already mentioned above, the conditioning surface is produced in particular by grinding an additionally curved back of the drill bit. In doing so, only one sub-region of the back face of the drill bit is ground starting from the lead groove when viewed in the circumferential direction. The normally circular area of the back of the drill bit thus still adjoins the flattened area when viewed in the peripheral direction. Thus, the flattened area forming the conditioning surface covers only a portion of the entire predetermined angular range of the back face of the drill bit when viewed in cross-section. For example, it covers at least 25% of the entire angular range of the back face of the bit, and covers, for example, 30% to 60%. For example, in embodiments of a drill bit having two flutes, the entire angular range covered by the back of the bit is typically between 80 ° and 120 °, depending on the design of the flutes. Therefore, the planarization adjustment surface generally covers an angular range of between 30 ° and 60 ° in total.

Furthermore, the orientation of the adjustment surface is selected such that it encloses a preferably obtuse angle with the curved peripheral surface when viewed in cross-section, in particular in the range of 80 ° or 90 ° to 160 °, and in particular in the range of 115 ° to 145 °. In this case, the angle is measured as the internal angle between the adjustment surface and the tangent to the curved peripheral surface at the point where the adjustment surface meets the curved peripheral surface.

Due to the selected obtuse angle, the surface normal of the adjustment surface is oriented at an oblique angle to the radial direction. The width of the adjusting surface is therefore generally selected to be as large as possible.

The adjustment surface extends in the longitudinal direction and comprises a front end which is oriented towards the bit tip of the drill bit and at which it transitions into the curved peripheral surface, in particular via a step.

In addition, the adjustment surface extends in the longitudinal direction over a length that is preferably a multiple of the nominal diameter of the drill bit. For example, the length is at least twice the nominal diameter, and for example greater than three or four times the nominal diameter. In principle, there is the possibility of introducing the adjustment surface to the back of the drill bit up to the drill bit tip or almost the drill bit tip. In order to ensure reliable drilling results, the adjustment surface terminates at least one, preferably at least two times the nominal diameter before the drill bit tip. However, the conditioning surface is preferably at most 70% of the total length of the cutting area. The term "cutting region" is understood to mean the region of the drill provided with flutes.

The term "drill tip" refers in the present invention to the front face of the drill in which the main blades for the drilling process are formed. The nominal diameter is twice the distance from the radially outermost chamfer of the respective primary blade to the rotational axis of the drill bit.

In an advantageous development, the twist angle is chosen to be >5 ° and in particular >20 °, and in particular in the range of 20 ° to 45 °. Thus, a conventional twist angle is used which facilitates efficient chip transfer. At the same time, the maximum possible adjustment length is achieved.

In addition to the axial movement of the clamping sleeve in the longitudinal direction along the drill bit, length adjustment generally requires a rotational movement of the clamping sleeve such that the cutting insert attached to the clamping sleeve is oriented in a defined angular position relative to the adjustment surface.

According to a first design variant, a free rotatability of the clamping sleeve is provided. The clamping sleeve itself can thus rotate freely around the drill bit in this design variant. If the cutting insert is attached in the holder seat of the clamping sleeve, some kind of guidance is usually provided via the cutting insert, since the cutting insert has an abutment side which extends parallel to the adjustment surface and abuts against the adjustment surface or is only slightly spaced from the adjustment surface. In order to avoid a collision of the cutting insert, and in particular of this abutment side, with the circular section of the drill back face, it is therefore necessary to rotate the clamping sleeve about the axis of rotation, i.e. in particular according to the twist angle of the adjustment surface.

In an advantageous development, a positive guide is provided between the drill bit and the clamping sleeve with the aid of the guide element, as opposed to a free adjustability. This means that the drill bit and the clamping sleeve are positively guided together mechanically by the guide element in such a way that a rotational movement of the clamping sleeve about the rotational axis and thus about the drill bit is performed with a length adjustment of the clamping sleeve relative to the drill bit. This is done in particular by means of guide grooves into which the corresponding guide pins engage. Preferably, the guide groove is formed on the drill bit and the guide pin is formed on the interior of the clamping sleeve. In this case, too, the guide groove suitably extends helically, i.e. in particular at the same twist angle as the adjustment surface.

In a preferred embodiment, the guide element, i.e. in particular the guide groove, is also formed on one of the bit backs of the drill bit. This may in principle be the back of the drill bit forming the adjustment surface. However, it is preferably another bit back surface on which no adjustment surface is formed.

In general, the adjustment surface is formed on only one of the bit backs. The guide element is suitably formed on only one of the drill bit backs.

For the clamping and fastening of the drill bit in the clamping sleeve, the clamping sleeve is designed, for example, in the manner of an expansion chuck or comprises special radial fastening elements, for example, clamping screws. In a preferred embodiment, it has a slotted quill that is designed to be received into a tool holder, with clamping force applied via the tool holder. Specifically, a clamping sleeve as described in DE 102017210986a1 is used.

Drawings

Exemplary embodiments of the present invention are explained in more detail below based on the drawings. These figures partially show a simplified illustration:

figure 1 is a side view of a drilling/inversion tool according to the prior art,

figure 2 is a perspective view of a drill bit according to the present invention,

figure 3A is a cross-sectional view through a cross-section of the drill bit according to figure 3B along section line a-a,

figure 3B is a side view of a drill bit according to the present invention,

fig. 4 is a perspective view of a clamping sleeve for receiving and securing a drill bit.

Detailed Description

The combination tool 2 shown in fig. 1 is designed as a drilling/chamfering tool. Which extends in the longitudinal direction 4 along the axis of rotation R. The combination tool comprises a drill bit 6 extending in the longitudinal direction 4, and a clamping sleeve 8. The clamping sleeve 8 serves to receive and fasten the drill bit 6, i.e. to fix said drill bit at a defined length position. In the prior art, it is possible to make variable length adjustments and fastenings of the drill bit 6. For example by means of radial clamping screws 10. At its front end, the clamping sleeve additionally comprises a cutting insert 12, which is designed as a chamfering tool with a cutting edge. In an exemplary embodiment, the cutting edge is oriented obliquely to the longitudinal direction 4 or alternatively perpendicularly thereto. Which is used to form a chamfer/bevel or even a widened countersink at the end of a bore hole formed using the drill bit 6. The cutting insert 12 comprises an abutment side (not described in more detail) which extends parallel to the longitudinal direction and thus also parallel to the adjustment surface 16. The cutting insert 12 is arranged in a holder 38 (see fig. 4 in this regard).

The drill bit 6 is a fluted drill bit 6, i.e. a drill bit having a flute 14. Specifically, two grooves are provided, which are designed to extend helically at a twist angle γ (this point is referred to fig. 3B). The adjustment surface 16 can also be seen. According to prior art, the adjustment surface in the drill bit shown in fig. 1 extends parallel to the longitudinal direction 4. Which is incorporated into one of the bit backs 18 formed between the flutes 14.

Fig. 2 shows a drill bit 6 according to the invention. Which also extends in the longitudinal direction 4 and comprises a rear shaft region 20 adjoining a cutting region 22 provided with the recess 14. At its forward end, the drill bit has a drill tip 24. A primary insert for a drilling process is formed on the drill bit tip. Starting from the front main insert, the groove 14 extends over the length of the cutting area.

In the drill according to the invention, the adjustment surface 16 is also designed as a flattened partial surface of the back side 18 of the drill. In the drill bit 6 according to the invention, the adjustment surface 16 extends helically, i.e. in particular at the same twist angle γ at which the flutes 14 are also so oriented. The torsion angle y is here determined by the inclination/orientation of the groove or the transversely defined line of the adjusting surface with respect to the longitudinal direction 4, as shown in a side view (this point is referred to fig. 3B).

The adjustment surface 16 is designed to be flat. This is to be understood in particular to mean that the conditioning surface is spanned at each point of its surface by two linear vectors, one vector extending parallel to the longitudinal direction 4 and the other vector extending perpendicular to the longitudinal direction 4. Typically, the adjustment surface is designed with a spiral flat side. It has no curvature, in particular no convexly curved surface area, compared to the conventional bit back face 18.

In particular, the adjustment surface 16 starts at the rear end of the bit back face 18 and preferably extends in the longitudinal direction 4 via a larger sub-region of the cutting region 20. For example, the conditioning surface 16 extends over 30% to 70% of the length of the cutting region 20; in the exemplary embodiment, conditioning surface 16 extends over approximately 50% of the length of cutting region 22.

The adjustment surface 16 has a preferably constant width or at least a substantially constant width over its entire length. This means that their laterally delimited boundary lines all extend parallel to one another.

Specifically, the adjustment surface 16 is formed by grinding one of two bit backs 18. The position and orientation of the adjustment surface 16 can be seen in particular in fig. 3A. As can be seen from this figure, the adjustment surface 16 tapers on one side into the leading groove 14. On its opposite edge, the adjusting surface transitions into the curved peripheral side 26 of the drill back 18. In particular with the tangent 28, the adjustment surface is used, which encloses an obtuse angle α, in the exemplary embodiment approximately 135 °.

It can also be seen that the adjustment surface 16 covers an angular range β 1 which is approximately half of the total angular range β covered by the bit back face 18.

In a preferred embodiment, the drill bit 2 also has a guide groove 29, which is indicated by way of example in fig. 3A. This guide groove 29 provides a positive guide for the clamping sleeve 8. The guide groove 29 is introduced into the bit back 18 opposite the bit back 18 into which the adjustment surface 16 is introduced. The guide groove 29 is introduced into the peripheral side 26 from the outside and extends helically at the same twist angle γ as the groove 14. A guide pin, not shown here, engages in this guide groove 29 and is formed on the interior of the clamping sleeve 8. The guide groove 29 and the guide pin define a positive guide of the clamping sleeve 8 on the drill bit 6, so that the clamping sleeve 8 is automatically rotated in the longitudinal movement of the clamping sleeve 8 along the drill bit 6.

As can also be seen in FIG. 3A, the drill bits 6 also typically have cooling passages 30, one extending in each bit back face 18. Thus, the cooling passage 30 also extends spirally.

Furthermore, it can be seen from the sectional view in fig. 3A that the peripheral sides of the two bit backs 18 are slightly radially concave compared to a circle with the bit nominal diameter D.

The two drill bit backs 18 each have only one support chamfer 32 on the side oriented toward the front guide groove 14, which is usually provided with a side insert. The nominal diameter D is defined by the main blades on the end of the drill bit 6.

The support chamfer 32 is removed and is not present in the region of the conditioning surface 16.

Fig. 4 also shows a preferred clamping sleeve 8. Which corresponds to the known clamping sleeve described in DE 102017210986a 1. The clamping sleeve includes a rear grooved clamping shaft 34 and a front machining head 36 in which a holder 38 for receiving the cutting insert 12 is formed. The holder 38 is designed to receive the cutting insert 12 with a high degree of accuracy. The arrangement and orientation of the cutting insert 12 and the cutting edge 13, even with respect to the adjustment surface 16, is similar to that described in relation to fig. 1.

In general, the clamping sleeve 8 comprises a cylindrical socket into which a drill bit can be inserted in variable lengths. The clamping sleeve 8 shown in fig. 4 is received by the tool holder and clamped therein. At the same time, the drill bit 6 is also clamped via the grooved clamping sleeve.