JP3805834B2 - Drilling blade and method for manufacturing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drilling tool for drilling a circular hole in a workpiece and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, as shown in FIG. 10A, a drilling tool using the above-described drilling tool is known. This drilling tool includes a tool mounting portion 90, and a center drill 92 is detachably mounted at the center thereof, and a drilling cutter 91 is mounted at a position coaxial with the center drill 92. The drilling cutter 91 integrally includes a disc-shaped base portion 95 having a through hole 95a in the center and a cylindrical body 94 extending forward (rightward in the drawing) from the base portion 95. A blade 93 is formed at the tip of the center drill 92 and a drill portion is also formed at the tip of the center drill 92. The base 95 is fixed to the tool mounting portion 90 in a state where the tool mounting portion 90 is inserted into the through hole 95a of the base portion 95. In this state, the drill portion of the center drill 92 is more than the blade 93. Is protruding forward.
[0003]
When the whole drilling tool is rotated at a high speed and pressed against a workpiece (for example, the wall 96), the center drill 92 first drills and positions it first, and further surrounds the periphery of the blade at the tip of the body 94. By cutting 93, a hole having the same diameter as that of the body 94 is finally drilled in the wall 96.
[0004]
By the way, the punching tool 91 in which the base 95 and the body 94 are integrated as described above has high strength reliability and a simple structure. Large-scale processing such as hollowing out the material into a cylindrical shape is necessary, which requires a long processing time and a material cost that is very high.
[0005]
Therefore, conventionally, as shown in FIG. 10B, a cylindrical body 94 and a disc-shaped base 95 are manufactured as separate members, and the base end (see FIG. The left end) is formed with a stepped portion 95b that can be fitted, and the base end of the body 94 is fitted to the stepped portion 95b, and both are connected by a fastener such as welding or a bolt. .
[0006]
[Problems to be solved by the invention]
When the body 94 and the base portion 95 are connected by welding, there is a disadvantage that the processing time becomes long. In addition, the material of the body 94 and the material of the base portion 95 must be the same in principle, and the material of the base portion 95 is remarkably limited. For example, the body 94 that requires relatively high mechanical strength is made of steel. It is not possible to select a preferable material such as a lightweight aluminum alloy die-cast product for the base 95 which uses a pipe material made of a material and does not require much strength.
[0007]
On the other hand, when the cylindrical body 94 and the base portion 95 are fastened with bolts, there is a drawback that the reliability of the connection strength is low and the structure is complicated. Moreover, since a big bolt head protrudes outside, there also exists a problem that an external appearance is impaired.
[0008]
In view of such circumstances, an object of the present invention is to provide a drilling blade that can be easily manufactured at low cost and has high strength and reliability, and a method for manufacturing the same.
[0009]
[Means for Solving the Problems]
As a means for solving the above-mentioned problem, the present invention is such that a cylindrical body is joined to a base portion mounted on a blade mounting portion, and the entire body is pressed against a workpiece while being rotationally driven around the central axis of the body. In the drilling tool configured to perforate the workpiece, a stepped portion having a shape that can contact the base end surface of the body and fit inside the base end portion of the body is formed on the base portion. The base end portion of the body and the stepped portion are fitted to both the base portion and the base end portion of the body, and the base end face and the stepped portion of the body are in contact with each other in a state of being in axial contact with each other. pin insertion hole in the radial direction is provided in a different plurality of locations in a circumferential direction, these pin insertion hole, elastically deformable spring pin diameter direction by Rukoto is pressed in diameter state, the proximal end face of the body And the above stepped portion To state is one that is maintained.
[0010]
Further, the present invention is a method for manufacturing the above-mentioned drilling tool, which manufactures a base portion having a stepped portion that can be brought into contact with the base end surface of the body and can be fitted inside the base end portion of the body. The base portion and the base end portion of the body are fitted in the base end portion of the body and the base end surface of the body and the step portion are in axial contact with each other in the circumferential direction between the base portion and the base end portion of the body. the radial pin insertion hole provided in different plurality of places, these pin insertion hole, by press-fitting in the direction of reducing the diameter of the elastically deformable spring pins contracted state, the proximal end face of the body and the stepped portion Is maintained in a state of pressure contact in the axial direction .
[0011]
According to the above configuration, only the work of providing the pin insertion hole in the base part and the body base end part while pressing the stepped part of the base part and the body base end face and the work of press-fitting the spring pin into the pin insertion hole are performed. Thus, the base and the body can be easily connected. In addition, the press-fit of the spring pin maintains the pressure contact state in the axial direction between the base step and the body base end surface, so there is no backlash of the body with respect to the base, and the connection portion between the two is highly reliable. Sex is obtained.
[0012]
Also, unlike the connection by welding, the base material can be set freely without being restricted by the body material, so the use of an aluminum alloy die-cast product as the base reduces the overall cost and weight of the blade. It can be achieved and the mass productivity can be increased.
[0013]
A single type of body may be used, or a plurality of types of bodies having different diameters may be prepared in advance, and an appropriate body may be selected and used according to the target drilling diameter. In the latter case, a plurality of types of bases having step portions corresponding to the diameters of the respective bodies may be manufactured. However, a base having a shape in which a plurality of substantially concentric ribs protrude from the substrate is manufactured. Of these ribs, a rib having an outer diameter substantially equal to the inner diameter of the body to be used is selected as a step forming rib, and the portion outside the step forming rib is substantially equal to the thickness of the body. If the method of fitting the base end portion of the body to the step portion formed by the step forming rib and the substrate is removed, the common base portion is used regardless of the diameter of the body. It is also possible to make the final shape compact while forming this base only with a single mold.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
A method for manufacturing a punching tool according to the present invention will be described with reference to FIGS. In this embodiment, a plurality of types of cylindrical bodies 20 (see FIG. 4) are prepared corresponding to a plurality of types of target drilling diameters set in advance, and one of these bodies 20 is selected. The case where it is used will be described.
[0015]
1) Molding of the base First, the base 10 having a shape as shown in FIGS. 1 (a) and 1 (b) is manufactured. The base 10 has a disk-like substrate 11 on which ribs 12A, 12B, and 12C are projected. The rib 12A is formed in a substantially ring shape in plan view at the center of the substrate 11, and a plurality of (seven in the illustrated example) ribs 12B are intermittently arranged on the outer side of the rib 12A. The rib 12B is formed at a position slightly inside the outer peripheral surface of the substrate 11. That is, a circumferential groove 13 is formed between the rib 12A and the innermost rib 12B and between the ribs 12B, and the stepped portion 14 is formed by the outermost rib 12B and the peripheral edge of the substrate 11. Is formed. The ribs 12 </ b> C are formed so as to cross the plurality of ribs 12 </ b> B in the radial direction, and are provided at a plurality of different locations (four locations in the illustrated example) in the circumferential direction.
[0016]
In addition, a screw hole 15 is formed at the center of the base portion 10 to be screwed into a male screw portion in a tool mounting portion (not shown), and a plurality of through holes 16 for scrap removal are formed around the screw hole 15. Is formed.
[0017]
Here, the outer diameter of each rib 12B is set to a diameter substantially equal to the inner diameter of each body 20 prepared in advance.
[0018]
The base 10 can be easily integrally formed by, for example, a die casting method, and a lightweight base 10 can be obtained by selecting an aluminum alloy as the material.
[0019]
2) Removal of unnecessary portion of base portion Of the seven ribs 12B shown in FIG. 1, a rib having an outer diameter substantially equal to the inner diameter of the selected body 20 (in this example, the fourth rib counted from the radially inner side) (Rib) 12B is selected as a step forming rib, and all the other parts are removed with a lathe while leaving a cutting margin equivalent to the thickness of the body 20 on the radially outer side of the rib 12B. The portion of the ribs 12C existing in is also removed. As a result, as shown in FIGS. 2A and 2B, a new step 14 is formed by the rib 12 </ b> B selected as the step forming rib and the peripheral portion of the substrate 11.
[0020]
3) Body fitting and pin insertion hole drilling The newly formed step portion 14 has a base end portion of the body 20 having a predetermined diameter as shown in FIGS. 4 and 5 (the lower end portion in FIG. 4). ). The body 20 has a plurality of blade portions 24 fixed to the tip portion (the upper end portion in FIG. 4), and each blade portion 24 is formed of a sintered alloy, tool steel, or the like.
[0021]
The base 10 and the body 20 are compressed in the axial direction with the fitting state. For example, as shown in FIG. 4, the compression is performed by placing the base 10 on the table 30 upward (the direction in which the ribs 12 </ b> A to 12 </ b> C protrude upward), and the body 20 and the base 10 from above with the air piston 32 or the like. This can be done by applying pressure. The pressure p at the time of pressurization does not place an excessive strength load on the body 20, and the base end surface (the lower end surface in FIG. 4) of the body 20 is securely attached to the step portion 14 (specifically, the peripheral portion of the substrate 11). Set the pressure so that it can be pressed.
[0022]
With this pressure contact state, pin insertion holes 17 and 26 penetrating in the radial direction are drilled by drills or the like in the ribs 12C of the base 10 and the base end portions of the body 20 corresponding to the ribs 12C. .
[0023]
4) Press-fit of the spring pin While maintaining the above-mentioned pressurization state or releasing the pressurization, the spring pin 40 is press-fit over both the pin insertion holes 17 and 26.
[0024]
The spring pin 40 can be manufactured by, for example, winding a thin plate into a cylindrical shape and performing a heat treatment. As shown in FIGS. 7 and 8, the spring pin 40 has a C-shaped cross section with a gap 42 between both ends. It can be elastically deformed in the direction of diameter reduction by the gap 42. A tapered surface 44 is formed at the tip end portion (right end portion in FIG. 7A) of the spring pin 40 to facilitate press-fitting, and a rivet shape is formed at the tail end portion (left end portion in FIG. 7A). A flange portion 46 is formed. The spring pin 40 is preferably based on, for example, those defined in JIS B 2808.
[0025]
If the spring pin 40 is inserted into the pin insertion holes 17 and 26 from the outside (that is, from the pin insertion hole 26 side) in a reduced diameter state and penetrated through the pin insertion holes 17 and 26, the spring pin 40 is expanded. The outer peripheral surface of the spring pin 40 and the inner peripheral surfaces of the pin insertion holes 17 and 26 are pressed against each other by the elastic force in the radial direction, and the base 10 and the body 20 are connected and fixed by the spring pin 40. Further, since the flange portion 46 is formed at the tail end portion of the spring pin 40, the spring pin 40 is prevented from entering inside due to vibration or the like.
[0026]
According to such a manufacturing method, it is possible to easily manufacture a drilling tool having a simple structure with a low cost. Moreover, the pin insertion holes 17, 26 of the spring pin 40 is inserted in common, since the base end surface and the step portion 14 of the body 20 is positioned so as to coincide with each other in a state of being pressed in the axial direction, these When the spring pin 40 is press-fitted into the pin insertion holes 17 and 26, the axial contact state between the base end surface of the body 20 and the stepped portion 14 is secured, and the backlash of the body 20 with respect to the base 10 is ensured. It is possible to reliably prevent sticking and to obtain high reliability in terms of strength. In addition, unlike the connection by welding, the material of the base 10 can be freely selected regardless of the material of the body 20, so that the product can be made cheaper and lighter by manufacturing the base 10 with aluminum alloy die casting, Moreover, mass productivity can be improved.
[0027]
Furthermore, in the embodiment shown here, the following effects can also be obtained.
[0028]
(a) A plurality of types of ribs 12B are formed on the base portion 10 corresponding to a plurality of types of bodies 20 in advance, and unnecessary portions of the base portion 10 are deleted according to the body 20 to be used. In spite of the use of the body 20, all the bases 10 can be manufactured with a single mold. Therefore, the mass productivity of the base 10 can be further increased as compared with the case where the base 10 having a different shape depending on the diameter of the body 20 is manufactured.
[0029]
(b) In addition to the circumferential ribs 12A and 12B, the rib 12C continuous in the radial direction is formed, and the pin insertion hole 17 is provided in the rib 12C, so that the pin insertion hole 17 and the spring pin 40 are in contact with each other. A larger area can be secured, and the connection strength can be further increased accordingly.
[0030]
The spring pin 40 is strongly pressed against the inner peripheral surfaces of the pin insertion holes 17 and 26 by its elastic force, so that it hardly moves in the axial direction even if it receives vibration during use of the tool. As shown in FIG. 9, pin insertion holes 18 and 48 that match each other in a state where the spring pin 40 is press-fitted are provided in the base 10 and the side wall of the spring pin 40, respectively. If a further spring pin 50 is press-fitted so that the spring pin 50 penetrates the spring pin 40 in the diameter direction, the axial displacement of the spring pin 40 can be more reliably prevented.
[0031]
【The invention's effect】
As described above, according to the present invention, the spring pin is press-fitted into the pin insertion holes that match each other in a state where the base end portion of the body is fitted to the stepped portion of the base portion and the base portion and the body base end surface are pressed in the axial direction. since is obtained so as to maintain the pressure contact state of the shaft direction, a tool for drilling of inexpensive and simple structure can be easily manufactured, and can be maintained its strength highly reliable effect by There is.
[0032]
Moreover, the range of application of the material of the base is wide, and by using a die-cast product made of an aluminum alloy as the base, it is possible to reduce the overall cost and weight of the blade and improve mass production.
[0033]
Further, when a plurality of types of bodies having different diameters are prepared in advance and an appropriate body is selected, a base portion in which a plurality of substantially concentric ribs protrude from the substrate is manufactured, and each of the ribs described above is manufactured. Among them, a rib having an outer diameter substantially equal to the inner diameter of the body to be used is selected as the step forming rib, and the portion outside the step forming rib is the same as the thickness of the body. By removing the remaining and performing a method of fitting the base end of the body to the step formed by the step forming rib and the substrate, the shape of the base to be manufactured is made common, and its productivity The effect of being able to collect the shape of the final base in a compact manner can be obtained while further improving.
[Brief description of the drawings]
FIG. 1A is a plan view of a base immediately after molding, and FIG. 1B is a cross-sectional view taken along line AA in FIG.
2A is a plan view showing a base portion after the outer peripheral portion is removed, and FIG. 2B is a cross-sectional view taken along the line BB in FIG.
FIG. 3 is a cross-sectional plan view showing a state where a pin insertion hole is provided by fitting the base end portion of the body to the stepped portion of the base portion.
4 is a cross-sectional view taken along the line CC in FIG. 3;
FIG. 5 is a cross-sectional plan view showing a state in which a spring pin is press-fitted into the pin insertion hole.
6 is a cross-sectional view taken along the line DD of FIG.
7A is a side view of the spring pin, and FIG. 7B is a sectional view taken along line EE of FIG. 7A.
FIG. 8 is a perspective view of the spring pin.
FIG. 9 is a cross-sectional view showing an example in which another spring pin is passed through the spring pin.
FIG. 10A is a cross-sectional side view showing a use state of a conventional integrated drilling tool, and FIG. 10B is a cross-sectional side view showing a conventional separate drilling tool.
[Explanation of symbols]
10 Base 11 Substrate 12A, 12B, 12C Rib 14 Step 17 Pin insertion hole 20 Body 24 Blade 26 Pin insertion hole 40 Spring pin

Claims (5)

A cylindrical body is joined to the base mounted on the blade mounting portion, and the entire body is pressed against the workpiece while being rotationally driven around the central axis of the body, thereby forming a hole in the workpiece. In the opening blade, a stepped portion having a shape that can contact the base end surface of the body and fit inside the base end portion of the body is formed on the base portion, and is formed on both the base portion and the base end portion of the body. The base end portion of the body and the stepped portion are fitted to each other, and the radial pin insertion holes that match each other in a state where the base end surface of the body and the stepped portion are pressed in the axial direction are provided at a plurality of locations different in the circumferential direction. provided, these pin insertion hole, by Rukoto is pressed elastically deformable spring pin diameter direction in contracted state, the state is maintained in which the proximal end face of the body and and the stepped portion is pressed against the axially holes open, characterized in that it is Use cutlery.   2. The punching tool according to claim 1, wherein the base is made of an aluminum alloy die-cast product. A method for manufacturing the punching tool according to claim 1, wherein a base portion having a stepped portion that can be brought into contact with the base end surface of the body and can be fitted inside the base end portion of the body is manufactured. The base portion and the base end portion of the body are different in the circumferential direction while fitting the step portion of the base portion and the base end portion of the body and keeping the base end surface of the body and the step portion pressed in the axial direction. A plurality of radial pin insertion holes are provided at a plurality of different locations in the circumferential direction, and spring pins that are elastically deformable in the reduced diameter direction are press-fitted into these pin insertion holes in a reduced diameter state, thereby providing a base for the body. A manufacturing method of a punching tool characterized by maintaining a state in which an end face and the stepped portion are pressed in the axial direction .   4. The method for manufacturing a drilling cutter according to claim 3, wherein the base is manufactured by die-casting an aluminum alloy.   5. The method for manufacturing a drilling cutter according to claim 3 or 4, wherein a base portion having a shape in which a plurality of substantially concentric ribs protrude from a substrate is manufactured, and an inner diameter of a body to be used is substantially the same among the ribs. Select the rib with the same outer diameter as the rib for forming the stepped portion, and remove the portion outside the rib for forming the stepped portion, leaving only the dimension equivalent to the wall thickness of the body, forming the stepped portion A manufacturing method of a punching tool, wherein a base end portion of the body is fitted to a step portion formed by a rib for use and the substrate.

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