JP2021115690A - Boring tool - Google Patents

Abstract

To provide a boring tool for a rubber material that is capable of quickly forming a clear hole without causing chips to enter a hollow part, and less likely causes a failure such as damage and deformation even after it is repeatedly used.SOLUTION: A processing part 2 has a cutting edge part 3 and a rake face part 4. The rake face part 4 is formed of a first curved surface part 5 forming a curved surface shape extending curvedly in side surface view and a second curved surface part 6 arranged continuously to an extension end of the first curved surface part 5 and forming a curved surface shape extending curvedly around a rod center line C1. An edge part at the tip of the processing part 2 is positioned on a plane orthogonal to the rod center line C1. The cutting part 3 is constituted of one edge part of the rake face part 4, and the side edge part extends to the tip of the processing part 2 while gently being curved so as to recess in a concave shape on the inside of the processing part 2 when the rake face part 4 is viewed from the front. One-side end part in a continuous part of the first and second curved surface parts 5, 6 constitutes an edge part 7 forming a sharp shape.SELECTED DRAWING: Figure 2

Description

The present invention relates to, for example, a drilling tool used when manufacturing a hollow rubber product made of a rubber material.

Conventionally, a hollow automobile part made of a rubber material such as a weather strip is subjected to a large number of drilling processes in the manufacturing process. The drilling process is generally performed using a drilling tool such as a drill or a cone. For example, the drilling tool disclosed in Patent Document 1 has a machined portion on the tip end side, while the base end side is. It has an elongated round bar shape that is sandwiched between rotary drive means such as the precision grinder "Leutor (registered trademark)". Approximately half of the processed portion on one side in the radial direction has a notched shape, while approximately half of the other side in the radial direction of the processed portion has a sharp tip. A rake face portion is formed in a region continuous with the notch portion in the machined portion, and the rake face portion gradually approaches the rod center line of the drilling tool toward the tip of the processed portion, and after approaching the rod center line, As it gets closer to the tip of the machined part, it gradually separates from the center line of the rod and bends back, forming a curved surface shape like a bow. The side edge portion of the rake face portion located on the opposite side of the cutout portion is a cutting edge portion for making a cut in the part to be machined, and the cutting edge portion has a gently curved shape when the rake face portion is viewed from the front. I'm doing it. Then, when the machined portion is pushed into the part to be machined while rotating the drilling tool around the center line of the rod, the cutting edge portion makes a circular notch in the part to be machined, and the rake face portion is formed by the cutting edge portion. A hole is formed by cutting out while scooping up to the opening tool insertion side.

Japanese Unexamined Patent Publication No. 2011-189492

By the way, in recent years, there has been a demand for increasing the processing speed of the above-mentioned drilling process in order to efficiently manufacture parts.

However, in the drilling tool of Patent Document 1, when the drilling process is performed by simply increasing the pushing speed of the part to be machined, the machined portion is processed before the portion cut out from the part to be machined by the cutting edge portion is scooped up by the scooping surface portion. It is pushed into the back side of the part, and the part to be cut out is not discharged to the drilling tool insertion side of the part to be processed and enters the hollow part of the part to be processed, or the part to be cut out is torn off from the part to be processed. The inner peripheral surface of the drilled hole will not be a clean cutting surface.

Further, since the tip portion of the processed portion of the drilling tool of Patent Document 1 has a sharp shape, it may be damaged or deformed in a short period of time if it is used repeatedly.

The present invention has been made in view of these points, and an object of the present invention is that a clean hole can be quickly formed without chips entering the hollow portion, and even if the use is repeated. An object of the present invention is to provide a drilling tool for a rubber material which is unlikely to cause a failure such as breakage or deformation.

In order to achieve the above object, the present invention is characterized in that the shapes of the rake face portion and the cutting edge portion in the processed portion are devised.

Specifically, while the processed portion is provided on the tip end side, the base end side is in the shape of a round bar sandwiched by the rotation driving means, and the processed portion is made of a rubber material by the rotational operation around the center line of the rod by the rotation driving means. The following measures were taken for drilling tools configured to perform drilling on the workpiece.

That is, in the first invention, the processed portion is formed with a cutting edge portion for making a cut in the workpiece and a rake face portion continuous with the cutting edge portion, and the rake face portion is the outer periphery of the processed portion. One region of two regions located on opposite sides of each other on the surface gradually approaches a predetermined position in the other region as it goes to the tip of the machined portion, and the other region gradually approaches a predetermined position in the other region as it goes from the predetermined position to the tip of the machined portion. A first curved surface portion having a curved surface shape that extends in a bow shape in a side view so as to gradually move away from the surface, and an inclined surface portion that gradually approaches the other region as it goes from the extending end of the first curved surface portion to the tip of the processed portion. The extension end edge portion is located on a plane orthogonal to the rod center line, and is composed of a second curved surface portion having a curved surface shape extending in a bow shape around the rod center line. The cutting edge portion is composed of one side edge portion of the rake face portion, and the side edge portion is gently curved so as to be recessed inside the processed portion when the rake face portion is viewed from the front. It extends to the tip of the processed portion, and one end of the continuous portion of the first and second curved surface portions constitutes a cutting edge portion having a sharp shape.

In the second invention, in the first invention, the tip of the processed portion has a bow shape when viewed in the direction of the rod center line, and has a U-shaped cross section having a predetermined thickness. ..

In the third invention, in the first or second invention, the processed portion has a symmetrical shape about the rod center line when the rake face portion is viewed from the front, and the cutting edge portion has the above-mentioned cutting edge portion. It is also formed on the other side edge portion of the rake face portion, and the cutting edge portion is also formed on the other side end portion in the continuous portion of the first and second curved surface portions.

In the first invention, when the machined portion is pushed into the workpiece while rotating the drilling tool around the center line of the rod, the cutting edge portion pierces the workpiece and the cutting edge portion starts from the portion pierced by the blade edge portion. Will proceed to the back side of the work piece while making a circular notch in the work piece. At this time, when the speed at which the drilling tool is pushed into the workpiece is increased, the second curved surface portion having a shape extending around the center line of the rod ensures that the cutout portion (chip) is separated from the workpiece together with the cutting edge portion. At the same time, the first curved surface portion is scooped up to the insertion side of the drilling tool. Therefore, even if the processed portion is pushed into the workpiece, the cut-out portion enters the hollow portion of the workpiece, or the cut-out portion is torn off from the workpiece, so that the inner peripheral surface of the hole formed becomes uneven. It is possible to prevent the cutting surface from becoming unclean. Further, since the second curved surface portion corresponding to the tip portion of the processed portion extends around the rod center line, the tip portion of the processed portion has a wide shape. Therefore, the rigidity of the tip portion of the processed portion is increased, and it is possible to prevent failures such as breakage and deformation from occurring even after repeated use.

In the second invention, since the section modulus of the tip of the machined portion in the drilling tool is increased, the rigidity of the tip of the machined portion is increased, and it is possible to reduce the occurrence of breakage during repeated use.

In the third invention, when the drilling tool is rotated forward, drilling can be performed by one cutting edge portion and the cutting edge portion, while when the drilling tool is reversed, drilling is performed by the other cutting edge portion and the cutting edge portion. Processing becomes possible. Therefore, the life of the drilling tool is doubled as compared with the drilling tool composed of only one cutting edge portion and the cutting edge portion, so that the component cost can be suppressed low.

It is a front view which shows the state which the drilling tool which concerns on embodiment of this invention is set in a leutor. It is a perspective view of the drilling tool which concerns on embodiment of this invention. It is an enlarged view of Part III of FIG. It is an IV arrow view of FIG. It is a V arrow view of FIG. It is a VI arrow view of FIG. It is a figure corresponding to FIG. 1 which shows the state just before performing a hole drilling process on a work piece. After FIG. 7, it is a figure which shows the state immediately after performing a hole drilling process in a work piece.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is essentially merely an example.

FIG. 1 shows a state in which the drilling tool 1 according to the embodiment of the present invention is set in the lutor 10 (rotational driving means). The drilling tool 1 is a tool having an elongated substantially round bar shape, and is, for example, a large number of holes 11b (see FIG. 8) in an automobile part made of a rubber material such as a weather strip 11 (workpiece) having a hollow portion 11a. ), While the processed portion 2 is provided on the tip end side, the base end side is sandwiched by the chuck portion 10a of the ruter 10.

As shown in FIG. 2, the processed portion 2 includes a cutting edge portion 3 for making a cut in the weather strip 11 and a rake face portion 4 continuous with the cutting edge portion 3, and a rod when the rake face portion 4 is viewed from the front. It has a symmetrical shape with respect to the center line C1.

As shown in FIG. 3, the rake face portion 4 is composed of a first curved surface portion 5 having a substantially I-shape when the rake face portion 4 is viewed from the front and a second curved surface portion 6 having a substantially half-moon shape.

As shown in FIGS. 3 to 6, the first curved surface portion 5 has two regions (hereinafter, one is referred to as a region 2A and the other is referred to as a region 2B) located on opposite sides of the outer peripheral surface of the processed portion 2. As the region 2A of () moves toward the tip of the machined portion 2, it gradually approaches a predetermined position in the region 2B, and as it goes from the predetermined position to the tip of the machined portion 2, it gradually separates from the region 2B and warps. It has a shape. In the embodiment of the present invention, as shown in FIG. 4, the first curved surface portion 5 is a metal rod having a round bar shape so that the rotation center of the rotary grindstone 9a having a radius R1 is orthogonal to the rod center line C1. It is formed by cutting toward the position near the end of.

The second curved surface portion 6 is inclined and extends so as to gradually approach the region 2B from the extending end of the first curved surface portion 5 toward the tip of the processed portion 2, and the extending end edge portion thereof is orthogonal to the rod center line C1. It is located on a plane. Further, the second curved surface portion 6 has a curved surface shape extending in a bow shape around the rod center line C1. In the embodiment of the present invention, as shown in FIG. 5, the second curved surface portion 6 is a metal rod having a round bar shape so that the rotation center of the rotary grindstone 9b having a radius R2 intersects the rod center line C1. It is formed by cutting toward the position near the end of the.

As shown in FIG. 5, the tip of the processed portion 2 has a bow shape when viewed in the direction of the rod center line C1 and has a U-shaped cross section having a predetermined thickness d1.

The cutting edge portion 3 is composed of each side edge portion of the rake face portion 4, and each side edge portion has a concave shape inside the processed portion 2 when the rake face portion 4 is viewed from the front, as shown in FIG. It extends to the tip of the machined portion 2 while gently curving so as to be recessed.

One side end portion and the other side end portion in the continuous portion of the first curved surface portion 5 and the second curved surface portion 6 form a pair of cutting edge portions 7 having a sharp shape.

Further, at the edge of the first curved surface portion 5 opposite to the second curved surface portion 6, a third curved surface portion 8 having a substantially triangular shape when the rake face portion 4 is viewed from the front is formed, and the third curved surface portion 8 is formed. Reference numeral 8 denotes a curved surface shape extending in a bow shape when viewed in the direction of the rod center line C1. The third curved surface portion 8 may not be provided on the drilling tool 1.

Then, as shown in FIGS. 7 and 8, the drilling tool 1 is configured such that the processing portion 2 drills the weather strip 11 by the rotational operation around the rod center line C1 by the lutor 10.

Next, the drilling process using the drilling tool 1 according to the embodiment of the present invention will be described in detail.

First, as shown in FIG. 1, the operator sandwiches the base end side of the drilling tool 1 in the chuck portion 10a of the lutor 10 and sets the weather strip 11 on the table (not shown).

Next, the lutor 10 is operated to rotate the drilling tool 1 forward around the rod center line C1 (arrow X1 in FIGS. 7 and 8), and then lower it (arrow Y1 in FIG. 8) to drill a rotating hole. The processed portion 2 of the tool 1 is pushed into the weather strip 11. Then, as shown in FIGS. 7 and 8, one cutting edge portion 7 pierces the weather strip 11 and one cutting edge portion 3 makes a circular notch in the weather strip 11 starting from the portion pierced by the cutting edge portion 7. While inserting it, it will proceed to the back side of the weather strip 11. At this time, when the speed at which the drilling tool 1 is pushed into the weather strip 11 is increased, the second curved surface portion 6 having a shape extending around the rod center line C1 weathers the cutout portion (chip M1) together with the one cutting edge portion 3. The first curved surface portion 5 is scooped up to the insertion side of the drilling tool 1 while being surely separated from the strip 11. As described above, according to the embodiment of the present invention, even if the processing portion 2 is pushed into the weather strip 11 in order to increase the processing speed during drilling, the chips M1 may enter the hollow portion 11a of the weather strip 11. It is possible to prevent the chips M1 from being torn off from the weather strip 11 and causing irregularities on the inner peripheral surface of the drilled hole 11b to prevent a clean cutting surface.

Further, in the drilling tool 1 of the present invention, the tip of the processed portion 2 has an arch shape when viewed in the direction of the rod center line C1 and has a U-shaped cross section having a predetermined thickness d1, so that the drilling tool 1 The cross-sectional coefficient of the tip of the processed portion 2 in the above becomes large. Therefore, the rigidity of the tip portion of the processed portion 2 is increased, and it is possible to reduce the occurrence of breakage during repeated use.

Further, as shown in FIG. 7, when the drilling tool 1 is reversed around the rod center line C1 (in the direction of arrow X2), the hole 11b is formed in the weather strip 11 by the other cutting edge portion 7 and the other cutting edge portion 3. Can be processed. That is, the drilling tool 1 according to the embodiment of the present invention can be drilled by one cutting edge portion 3 and the cutting edge portion 7 when it is rotated forward, while the other cutting edge portion 3 and the cutting edge portion can be drilled when it is reversed. The portion 7 enables drilling. As described above, since the life of the drilling tool 1 is doubled as compared with the drilling tool composed of only one cutting edge portion 3 and the cutting edge portion 7, the component cost can be suppressed low.

In the drilling tool 1 according to the embodiment of the present invention, the cutting edge portion 3 and the cutting edge portion 7 are provided symmetrically with respect to the rod center line C1, but only one of them may be provided.

Further, in the embodiment of the present invention, the drilling tool 1 is applied to the drilling process of the weather strip 11, but even if the parts are made of other rubber materials, the drilling tool 1 is used to perform the drilling process. It can be carried out.

The present invention is suitable, for example, as a drilling tool used when manufacturing a hollow rubber product made of a rubber material.

1 Drilling tool 2 Machining part 3 Cutting edge part 4 Scooping surface part 5 1st curved surface part 6 2nd curved surface part 7 Cutting edge part 10 Leutor (rotation drive means)
11 Weather strip (workpiece)
C1 bar center line M1 chips

Claims (3)

While the machined portion is provided on the tip end side, the base end side is in the shape of a round bar sandwiched by the rotation drive means, and the machined portion is formed into a hole in the work piece made of a rubber material by the rotational operation around the rod center line by the rotation drive means. A drilling tool designed to perform drilling.
In the processed portion, a cutting edge portion for making a cut in the workpiece and a rake face portion continuous with the cutting edge portion are formed.
The rake face portion gradually approaches a predetermined position in the other region as one region of two regions located on opposite sides of the outer peripheral surface of the processed portion approaches the tip of the processed portion, and the processing is performed from the predetermined position. A first curved surface portion having a curved surface shape that extends in a bow shape in a lateral view so as to gradually move away from the other region as it goes to the tip of the portion, and from the extending end of the first curved surface portion to the tip of the processed portion. As it gradually extends toward the other region, its extending end edge is located on a plane orthogonal to the rod center line, and forms a curved surface shape extending in an arch shape around the rod center line. Consists of a second curved surface
The cutting edge portion is composed of one side edge portion of the rake face portion, and the side edge portion is gently curved so as to be recessed inside the processed portion when the rake face portion is viewed from the front. However, it extends to the tip of the above-mentioned processing part,
A drilling tool characterized in that one end of a continuous portion of the first and second curved surface portions constitutes a cutting edge portion having a sharp shape. In the drilling tool according to claim 1,
A drilling tool characterized in that the tip of the processed portion has a bow shape when viewed in the direction of the center line of the rod and has a U-shaped cross section having a predetermined thickness. In the drilling tool according to claim 1 or 2.
The processed portion has a symmetrical shape centered on the rod center line when the rake face portion is viewed from the front.
The cutting edge portion is also formed on the other side edge portion of the rake face portion.
The drilling tool is characterized in that the cutting edge portion is also formed at the other end portion of the continuous portion of the first and second curved surface portions.

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