WO2020082977A1

WO2020082977A1 - Auger bit

Info

Publication number: WO2020082977A1
Application number: PCT/CN2019/108140
Authority: WO
Inventors: 任军; 李晨鹰
Original assignee: 博世电动工具（中国）有限公司
Priority date: 2018-10-26
Filing date: 2019-09-26
Publication date: 2020-04-30
Also published as: CN210025589U

Abstract

An auger bit (100), comprising: a handle body (10); a cutting chip removing portion (20) arranged along the axial direction from one end part of the handle body (10); and a head portion (30) provided with external threads arranged along the axial direction from one end part of the cutting chip removing portion (20), wherein the head portion (30) comprises a cylindrical shape provided with external threads arranged in the axial direction from the cutting chip removing portion (20) and a conical shape provided with external threads arranged in the axial direction from the cylindrical shape provided with external threads; the thread pitch of the external threads of the head portion (30) falls within the range of 1.05 millimeters to 1.15 millimeters, the cone angle (θ) of the conical shape falls within the range of 23° and 29°, and an outer diameter of the external threads of the cylindrical shape falls within the range of 6.1 millimeters to 6.3 millimeters. Also disclosed is a cordless handheld power tool equipped with the auger bit (100).

Description

Zhiluo

Technical field

The present application generally relates to a support drill, particularly a woodwork support drill for cordless handheld power tools.

Background technique

In the field of wood processing, Zhiluo drill is a relatively common tool. Generally, auger drills are installed on the chucks of power tools to quickly make holes in wood, especially in the construction of timber houses, for example.

For example, during the construction of a timber house, invisible holes are left in the timber before holes are made in the timber. In this case, the cutting edge of the support drill is very likely to hit the nail, causing the cutting edge to break and affect its use.

In addition, the auger drill is usually provided with a threaded head for guiding the auger drill toward the wood before the cutting edge of the auger drill contacts the wood. For a cordless handheld power tool, since it is powered by a battery, the power of the motor of the power tool and the torque it can provide are limited. In this case, how to design the structure of the support drill to maximize the torque requirements of the motor is a key issue.

Summary of the invention

The purpose of this application is to propose a supporting drill suitable for cordless handheld power tools, so as to have a better nail cutting function.

According to an aspect of the present application, a support drill is provided, which includes:

Handle body

Cutting chip evacuation portion provided axially from one end of the shank; and

An externally threaded head portion provided axially from one end of the cutting chip discharge portion, the head portion includes a cylindrical shape provided with external thread axially provided from the cutting chip removal portion, and An externally threaded cylindrical axially arranged cone with an external thread, the pitch of the external thread of the head is in the range of 1.05 mm to 1.15 mm, and the cone angle of the cone is 23 In the range between ° and 29 °, the outer diameter of the cylindrical thread is in the range between 6.1 mm and 6.3 mm.

Optionally, the axial total length of the head is 11.5 mm, and the cone angle of the cone is 26 °.

Optionally, the cutting chip evacuation portion has at least two helical wing portions, the helical wing portions spirally extending around the longitudinal center axis of the support drill and arranged symmetrically with respect to the rotation thereof, each spiral The wing-shaped portion is formed with a cutting edge at the end of the cutting chip evacuation portion where the head is extended, and a rotation trajectory surface generated by the cutting edge when the support drill rotates is inclined toward the shank body It is at an angle with respect to the longitudinal central axis, and the angle is in the range between 84 ° and 86 °.

Optionally, each cutting edge is straight.

Optionally, when viewed in the axial end view of the support drill, all straight lines of the cutting edges intersect the longitudinal center axis at the same point.

Optionally, the rake angle of each cutting edge (21a) is in the range of 12 ° and 16 °, and the rake angle of each cutting edge (21a) is in the range of 10 ° 30 ′ and 14 ° 30 ′ .

Optionally, the rake angle of each cutting edge is 14 °, and the rake angle (β) of each cutting edge is 12 ° 30 ′.

Optionally, along the cutting rotation direction of the support drill upstream of each cutting edge, a radially inward concave cut portion is formed between the head and the cutting chip discharge portion to ensure After the external thread of the head is cut, the cutting edge is cut immediately.

Optionally, the cutting chip evacuation part is provided integrally with the shank body, and / or the head part is provided with the cutting chip evacuation part integrally.

According to another aspect of the present application, there is also provided a cordless hand-held power tool, and the aforementioned supporting drill is installed in a chuck of the cordless hand-held power tool.

Using the technical means of this application, the possibility of cutting the cutting edge of the support drill in wood processing due to cutting nails is minimized. In addition, the design of the threaded head is optimized for the motor torque of the cordless handheld power tool, which improves The use efficiency of the auger.

BRIEF DESCRIPTION

The foregoing and other aspects of the present application will be more fully understood from the detailed description to be described later in conjunction with the following drawings. It should be pointed out that the scale of each drawing may be different for the purpose of clarity, but this does not affect the understanding of this application. In the drawings:

FIG. 1 schematically shows an axial side view of a support drill according to an embodiment of the present application;

FIG. 2 schematically shows an axial side view of a part of the support drill, particularly its head;

Fig. 3 schematically shows an axial end view as seen from the head of the support drill.

detailed description

In each drawing of the present application, features with the same structure or similar functions are denoted by the same reference signs.

FIG. 1 schematically shows an axial side view of a support drill 100 according to an embodiment of the present application. The support drill 100 generally includes a shank body 10, a cutting chip evacuation portion 20 disposed axially from one end of the shank body 10, preferably integrally disposed in the axial direction, and an opposite end of the cutting chip evacuation portion 20 opposite to the shank body 10 An externally threaded head 30 is provided in the axial direction, preferably integrally in the axial direction. In the present application, the longitudinal central axes of the shank 10, cutting chip 20 and the head 30 of the support drill 100 are collinear, and are all longitudinal center axes O of the support drill 100. The support drill 100 is integrally formed of a high-strength metal such as an alloy. The shank body 10 is provided with a clamping portion that can be mounted on a chuck of a power tool, especially a cordless handheld power tool (not shown), for example, the end of the shank body 10 opposite to the cutting chip evacuation portion 20 is hexagonal in order to After the support drill 100 is fixed in place on the chuck, driven by the motor of the power tool, it rotates around its longitudinal central axis, so as to perform wood hole drilling.

The head 30 is located upstream of the cutting and chip removing part 20 in the direction in which the support drill 100 drills in the wood. The main function of the head 30 is that when the support drill 100 is mounted on the power tool for making holes in the wood, the head 30 can first contact the surface of the wood in order to locate the hole to be drilled. Then, as the head 30 is rotated by the motor of the power tool, under the action of the longitudinal pressing force, the external thread of the head 30 is screwed into the wood, and under the guidance of the external thread of the head 30, it rotates The cutting chip evacuation part 20 is driven toward the wood to perform hole cutting.

Referring specifically to FIG. 2, the head 30 generally has a cylindrical shape with a cone at one end, and an external thread is machined on the outer surface. That is, the screw head 30 includes a screw cylinder extending axially from the cutting chip discharge portion 20 and a screw cone extending axially from the screw cylinder. Viewed in an axial cross-section passing through the longitudinal center axis O of the support drill 100, the angle θ between the straight lines connected by the outermost boundary (point) of the conical external thread (ie, the cone of the head 30 Angle) is between 23 ° and 29 °, preferably 26 °. Preferably, the axial length of the threaded head 30 is 11.5 mm. Preferably, in order to ensure that the motor of the cordless hand-held power tool can provide sufficient torque for the head 30 and to ensure that the propeller drill 100 has sufficient advancing speed at the beginning of opening, the thread pitch of the external thread of the head 30 should be 1.05 mm to 1.15 Between millimeters. In addition, the thread outer diameter of the head 30 should be between 6.1 mm and 6.3 mm.

The cutting chip evacuation portion 20 has a spiral shape, for example, two wings 23 spirally extending around the longitudinal center axis O of the support drill 100 are integrally formed. The two spiral wings 23 are arranged rotationally symmetrically around the longitudinal center axis O. Although the cutting chip evacuation portion 20 has two spiral wing portions 23 in the illustrated embodiment, those skilled in the art should understand that the number of spiral wing portions 23 may also be greater than two. A face 21 is formed at the end of each spiral wing 23 near the head 30. Therefore, the cutting surface 21 defines the two cutting edges 21a of the cutting chip evacuation portion 20, as shown. When the support drill 100 rotates around the cutting rotation direction R, the cutting edge 21a can always contact the wood being holed before the rest of the corresponding spiral wing portion 23.

As shown in FIG. 2, according to the relevant specification definition in the art, the rake angle а of each cutting edge 21a is in the range of 12 ° and 16 °, preferably 14 °. In addition, the clearance angle β of each cutting edge 21a is in the range of 10 ° 30 ′ and 14 ° 30 ′, preferably 12 ° 30 ′. The selection of the aforementioned rake angle and rake angle of the cutting edge 21a is based on the best reasonable value (range) determined by the applicant in practice, so as to ensure the minimum power consumption of the cordless handheld power tool powered only by the battery and The longest processing time.

In the embodiment of the present application, each cutting edge 21a is straight. Further, as shown in FIG. 3, when viewed in the axial end view of the braided drill 100, the straight lines of the two cutting edges 21 a are collinear and pass through the longitudinal center axis O of the braided drill 100. Therefore, when the cutting edge 21a is cut in wood, the energy consumption of the cordless handheld power tool can be reduced and the rotation of the support drill 100 can be kept as smooth as possible.

As shown in FIG. 1, when viewed in an axial side view of the support drill 100, the cutting edge 21 a and the longitudinal center axis O intersect at a point at the same time, and the two cutting edges 21 a are arranged mirror-symmetrically with respect to the longitudinal center axis O. As the support drill 100 rotates about its longitudinal center axis O, the rotation path surface formed by the cutting edge 21a is inclined toward the downstream direction, that is, toward the shank 10 at an angle γ with respect to the longitudinal center axis O. The angle γ is in the range between 84 ° and 86 °. In this way, when the chip removal section 20 performs hole cutting in wood, if there is a nail in the wood, the portion of the cutting edge 21a near the longitudinal center axis O (ie, the radius from the longitudinal center axis O is smaller) (Part) First contact with the nail, so that the blocking torque generated when colliding with the nail is smaller, and the destructive force to the cutting edge 21a is smaller, which helps protect the integrity of the cutting edge 21a.

In order to enable the cutting operation of the support drill 100 to smoothly transition from the external thread of the head 30 to the cutting edge 21a of the cutting chip 20, that is, to cut the external thread of the head in the wood when the support drill 100 rotates At the end, the cutting edge 21a continues to cut in the wood without hindrance, and at the same time, in order to enable the cutting chips 21a to generate chips during the cutting can be quickly discharged, at the root of the head 30 and the cutting edge of the cutting chip 20 A radially inward concave cut portion 40 is formed between 21a, so that when the support drill 100 rotates for cutting, the cutting edge 21a of the chip removal portion 20 is immediately followed by the external thread cutting of the head 30 Perform cutting. In this way, the support drill 100 can be guided and moved in the wood by the head 30 at the initial stage, and then the cutting edge 21a can be used for smooth cutting. In addition, each concave cut portion 40 communicates with the chip guide groove between the two spiral wing portions 23, so that the debris generated when the head 30 is drilled in the wood can quickly follow the concave cut portion 40 Introduced into the chip guide groove and discharged.

In the context of this application, the various embodiments can be combined with one another arbitrarily. Although specific embodiments of the present application are described in detail here, they are given for explanatory purposes only and should not be considered as limiting the scope of the present application. Without departing from the spirit and scope of this application, various substitutions, changes, and modifications can be conceived.

Claims

A support auger (100), characterized in that it includes:

Handle body (10);

Cutting chip evacuation portion (20) axially provided from one end of the shank body (10); and

A head (30) provided with an external thread is provided axially from one end of the cutting chip evacuation part (20), and the head part (30) includes an axially arranged self cutting chip evacuation part (20) Cylindrical with external threads and conical with external threads arranged axially from the cylindrical with external threads, the pitch of the external threads of the head (30) is between 1.05 mm and 1.15 mm In the range between, the cone angle (θ) is between 23 ° and 29 °, and the outer diameter of the cylindrical thread is between 6.1 mm and 6.3 mm.
The support auger (100) according to claim 1, characterized in that the axial total length of the head (30) is 11.5 mm, and the cone angle (θ) of the conical shape is 26 °.
The support auger (100) according to claim 1 or 2, characterized in that the cutting chip evacuation portion (20) has at least two spiral wing portions (23), the spiral wing portion (23) Helically extending around the longitudinal central axis (O) of the support drill (100) and arranged symmetrically with respect to its rotation, each spiral-shaped wing portion (23) extends at the cutting chip removal portion (20) A cutting edge (21a) is formed at an end of the head (30), and a rotation trajectory surface generated by the cutting edge (21a) when the support drill (100) rotates faces the shank (10 ) Inclined and at an angle (γ) with respect to the longitudinal central axis (O), the angle (γ) being in the range between 84 ° and 86 °.
The auger drill (100) according to claim 3, characterized in that each cutting edge (21a) is straight.
The auger drill (100) according to claim 4, characterized in that, when viewed in the axial end view of the auger drill (100), the straight lines of all cutting edges (21a) and the longitudinal central axis (O) Intersect at the same point.
The support drill (100) according to claim 5, characterized in that the rake angle (а) of each cutting edge (21a) is in the range of 12 ° and 16 °, and each cutting edge (21a) The clearance angle (β) is within the range of 10 ° 30 ′ and 14 ° 30 ′.
The support drill (100) according to claim 5, characterized in that the rake angle (а) of each cutting edge (21a) is 14 °, and the rake angle (β) of each cutting edge (21a) is 12 ° 30 ′.
The support drill (100) according to claim 3, characterized in that, along the cutting rotation direction (R) of the support drill (100) upstream of each cutting edge (21a), a radial direction An internal undercut (40) is formed between the head (30) and the cutting chip evacuation part (20) to ensure that the external thread of the head (30) ends immediately after the cutting The blade (21a) cuts.
The auger drill (100) according to claim 1 or 2, characterized in that the cutting chip evacuation part (20) is provided integrally with the shank body (10), and / or the head part (30) It is provided integrally with the cutting chip evacuation part (20).
A cordless hand-held power tool, characterized in that a support drill (100) according to any one of claims 1 to 9 is installed in a chuck of the cordless hand-held power tool.