CN2064276U - Twist drill with three cutting edges - Google Patents

Abstract

A three cutting twist drill of the utility model is that the rake face curvature of three helix chip spaces on the foundation of prime twist drills to make three lead cutting edges 9, 10, 11, which are formed by that three rake faces and three main last knife faces are intersected, be as a concave arc knife. As a result, this causes chips, which are cut when drilling, to be as concave section chips, the basic deformation of chips is enlarged, so the chips only need to generate micro-redundant deformation, and the chips can automatically be broken off. The twist drill also has the advantages of good centering capability, high stock-removing efficiency, high process quality, big bending strength, big torsion rigidity, etc., and three cutting twist drill is suitable to various drilling machine steel material at high rate or other ductility metallic material.

Description

Twist drill with three cutting edges

The utility model is the three sword fluted drills that a kind of relevant machining is used.

Existing three sword fluted drills, generally comprise working portion 1 and shank 2, on working portion 1, be processed with three equally distributed spirality chip areas 3,4,5, to form three rake faces of drill edge, the end of working portion 1 is an apex point, the conical surface on the apex point partly is three main back knife faces 6,7,8, three rake faces and three main back knife faces intersect three linear pattern main cutting edges 9 of formation respectively, 10,11, at spirality chip area 3,4, the 5 close core places of boring are processed with three pits 12,13,14, to form the rake face and the filings-containing cavity of core cutting edge, three main back knife faces 6,7,8 converge the brill core point that forms a triangular taper at drill bit axle center place, this kind drill bit is not owing to have chisel edge, the self-centering performance when having improved bit cutting significantly at brill core place.Characteristics such as also have bending strength simultaneously and torsional rigidity is big, and guidance quality is good.But this kind three sword fluted drills are when drill for high-speed steel material or other plastic metal materials, because chip deformation is insufficient, cutting temperature is higher, it is tough that the smear metal deliquescing becomes, chip breaking is difficulty relatively, in order to reach the purpose of chip breaking, often has to suitably reduce cutting speed or grind chip breaker on the drill bit rake face, thereby influenced the performance of its cutting ability, increased the workload of drill sharpening.For three sword fluted drills of minor diameter, because the width of chip area is narrow, when the drilling plastic metal material, often chip removal is smooth and easy inadequately, hinders carrying out smoothly of drilling processing.Therefore, the three sword fluted drills of developing a kind of excellent cutting performance are very necessary.

The purpose of this utility model is to provide a kind of three sword fluted drills, chip breaking voluntarily when drill for high-speed steel material or other plastic metal materials.

Solution of the present utility model is on the basis of former three sword fluted drills the curvature of the rake face of three spirality chip areas of drill bit to be increased, making three rake faces and three main back knife faces intersect formed three main cutting edges is the arcs of recesses sword, thereby the transverse shape of the smear metal of being downcut when making drilling changes, the rectangular cross section smear metal that forms during by the drilling of linear main cutting edge becomes the smear metal of arcs of recesses cross section, the basic distortion of smear metal increases, it is just broken only need to make it produce small additional deformation, has realized chip breaking voluntarily.

The utility model comprises working portion and shank, on working portion, be processed with three equally distributed spirality chip areas, to form three rake faces of drill edge, the end of working portion is an apex point, the conical surface on the apex point partly is three main back knife faces, three rake faces and three main back knife faces intersect three main cutting edges of formation respectively, be processed with three pits at the spirality chip area near boring the core place, to form the rake face and the filings-containing cavity of core cutting edge, three main back knife faces converge the unbearable point that forms a triangular taper at place, drill bit axle center, it is characterized in that the curvature increase with the rake face of three spirality chip areas, making three rake faces and three main back knife faces intersect formed three main cutting edges is the arcs of recesses sword.Thereby the transverse shape of the smear metal of being downcut when making drilling changes, the rectangular cross section smear metal that forms during by the drilling of linear main cutting edge becomes the smear metal of arcs of recesses cross section, the basic distortion of smear metal increases, and it is just broken only need to make it produce small additional deformation, has realized chip breaking voluntarily.Its feature is that also chip area is less near the radius of curvature in the cross section of land one side, can under the situation that does not increase width of chip space, suitably increase the chip space of groove like this, and make chip curling tightr, gullet-to-chip area ratio can reduce relatively, thereby makes chip removal more smooth and easy.

The utility model is because main cutting edge is the arcs of recesses sword, smear metal becomes the smear metal of arc cross section by the rectangular cross section smear metal during drilling, it is just broken only need to make it produce small additional deformation, realize chip breaking voluntarily, need not reduce cutting speed, perhaps on the drill bit rake face, ground chip breaker, help giving full play to the cutting ability of drill bit, simplify sharpening formality and equipment, reduced unproductive time, reduced production cost; Because the curvature in the cross section of chip area is bigger, under the situation that does not increase width of chip space, suitably increased chip space simultaneously, smear metal is curling tightr in addition, and gullet-to-chip area ratio can reduce relatively, thereby makes chip removal more smooth and easy.Such drill bit also has bending strength and torsional rigidity height simultaneously, and the self-centering performance is good, stock-removing efficiency and cutter life height, advantage such as the crudy in hole is good.Both be suitable on machine tool shallow bore hole processing, and can be used for again holing on Digit Control Machine Tool and the machining center lathe conventional engineering material.

Fig. 1 is a front view of the present utility model.

Fig. 2 is a left view of the present utility model.

Below in conjunction with drawings and Examples the utility model is further described.

The utility model as shown in drawings, comprise working portion 1 and shank 2, on working portion 1, be processed with three equally distributed spirality chip areas 3,4,5, to form three rake faces of drill edge, the end of working portion 1 is an apex point, the conical surface on the apex point partly is three main back knife faces 6,7,8, three rake faces and three main back knife faces intersect three main cutting edges 9 of formation respectively, 10,11, at spirality chip area 3,4, the 5 close core places of boring are processed with three pits 12,13,14, to form the rake face and the filings-containing cavity of core cutting edge, three main back knife faces 6,7,8 converge the unbearable point that forms a triangular taper at drill bit axle center place, it is characterized in that curvature increase, make three rake faces and three main back knife faces intersect formed three main cutting edges 9 rake face of three spirality chip areas, 10,11 is the arcs of recesses sword.Variation has taken place in the transverse shape of the smear metal of being downcut when making drilling like this, the rectangular cross section smear metal that forms during by the drilling of linear main cutting edge becomes the smear metal of arcs of recesses cross section, the basic distortion of smear metal increases, and it is just broken only need to make it produce small additional deformation.Its feature is that also chip area is bigger near the curvature in the cross section of land one side, be that radius of curvature R is less, can under the situation that does not increase width of chip space, suitably increase the chip space of groove like this, smear metal is curling tightr in addition, gullet-to-chip area ratio can reduce relatively, thereby makes chip removal more smooth and easy.This drill bit working portion 1 can adopt high speed steel material to make, and also available Hardmetal materials is made.

Claims (2)

1, a kind of three sword fluted drills, comprise working portion 1 and shank 2, on working portion 1, be processed with three equally distributed spirality chip areas 3,4,5, to form three rake faces of drill edge, the end of working portion 1 is an apex point, the conical surface on the apex point partly is three main back knife faces 6,7,8, three rake faces and three main back knife faces intersect three main cutting edges 9 of formation respectively, 10,11, at spirality chip area 3,4, the 5 close core places of boring are processed with three pits 12,13,14, to form the rake face and the filings-containing cavity of core cutting edge, three main back knife faces 6,7,8 converge the unbearable point that forms a triangular taper at drill bit axle center place, the curvature increase that is characterised in that the rake face of three spirality chip areas of the present utility model makes three rake faces and three main back knife faces intersect formed three main cutting edges 9,10,11 is the arcs of recesses sword.

2, a kind of three sword fluted drills according to claim 1 is characterized in that chip area is less near the radius of curvature in land one side cross section.