JP2002283114A - Boring method and boring tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish high-accuracy boring without lowering efficiency. SOLUTION: One hole 7e at one end of a work piece 17 is bored by an ordinary boring tool 39, and then the work piece 17 is inverted from right to left. In such a condition, a boring tool 15 is inserted from a hole 17a at the other end of the work piece 17, and a guide part 25 is supported on the bored hole 17e at one end. In such a condition, the boring tool 15 is moved in the direction where the work piece 17 is pulled out while rotated, whereby with the guide part 25 slidably supported on the bored hole 17e, a plurality of holes 17d, 17c, 17b, and 17a are simultaneously bored by each cutting tool 21. The guide part 25 can be expanded and contracted in the direction of the diameter of the boring tool 15 so that it is contracted in insertion, and expanded in boring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling method and a drilling tool for drilling a workpiece provided with a plurality of holes concentrically along a central axis thereof.

[0002]

2. Description of the Related Art For example, a workpiece having a plurality of holes through which a crankshaft and a camshaft are inserted, such as a crankcase that rotatably supports a crankshaft of a multi-cylinder engine and a cylinder head that rotatably supports a camshaft. In the drilling of an object, it is necessary to process the plurality of holes concentrically along the axial direction and to increase the degree of concentricity.

[0003] As a device for making such a hole, there are a guide bush system as shown in FIG. 9 and a guide bushless system as shown in FIG.

In the guide bush system, a tool 3 is inserted into a workpiece 1 having a large number of holes 1a, and a tip 3a of the tool 3 is rotatably supported by a guide bush 5 as shown in FIG. As shown in FIG. 9B, the distal end 3a and the proximal end 3b of the tool 3 are rotatably supported by the guide bushes 5 and 6, respectively. By moving the workpiece 1 rightward in the drawing while rotating the tool 3 in this state, the plurality of holes 1a are simultaneously machined by the plurality of cutting tools 7 provided on the outer periphery of the tool 3.

As such a guide bush system,
For example, it is described in JP-A-2000-23330. In this publication, processing is performed in a state where a guide bush is supported by a hole at an end of a workpiece.

On the other hand, in the guide bushless system shown in FIG. 10, the tool 9 has one cutting tool 11 at its tip and a guide portion 13 on the outer periphery along the base from the tip.
As shown in FIG. 10A, the tool 9 is inserted into the workpiece 1 from the right side in FIG.
As shown in (b), the holes 1a are sequentially machined, and the tool 9 is guided by inserting the guide portion 13 into the machined holes 1a at this time.

[0007]

However, in such a conventional drilling method using a drilling tool,
There are the following problems.

In the guide bush system shown in FIG. 9, it is necessary to mount a dedicated guide bush, which is not preferable in securing the degree of freedom with respect to the hole diameter, the hole position, and the entire length of the workpiece. In addition, there is a possibility that the tool may interfere, and there may be a restriction when other processes are integrated in the same process.

On the other hand, in the guide bushless method, since the previously machined hole guides the tool, the machining accuracy is easily affected by the accuracy of the machined hole. Particularly, in the case of FIG. Since the processing is performed while pressing the workpiece relatively forward, a large bending stress acts on the hole drilling tool, and high-precision hole drilling cannot be performed.

Accordingly, an object of the present invention is to enable high-precision drilling without deteriorating workability.

[0011]

In order to achieve the above-mentioned object, a first aspect of the present invention is a hole for performing a hole processing on a workpiece provided with a plurality of holes concentrically along a central axis thereof. In the machining method, at least one hole at one end of the workpiece is machined, and from the other end of the workpiece, a guide portion at a tip of a hole machining tool is contracted in a diametrical direction. After the insertion, the processed portion at the one end is supported in a state where the guide portion is expanded in a diametric direction, and the guide portion is rotated while rotating the hole processing tool. By moving the hole relative to the workpiece in a direction approaching the end of the hole, another hole is machined by the hole machining tool.

According to a second aspect of the present invention, in the drilling method of the first aspect, a plurality of cutting tools are provided along an axial direction on an outer periphery of a shaft portion of the drilling tool, and a guide portion is provided at one end. Each hole of the workpiece corresponding to the plurality of cutting tools is simultaneously processed while being supported by the processed holes.

According to a third aspect of the present invention, there is provided the drilling method according to the first aspect of the present invention, wherein one cutting tool is provided on an outer periphery of a shaft portion of the drilling tool, and the guide portion is supported by the drilled hole.
Move the drilling tool relative to the workpiece in the axial direction,
Holes adjacent to the processed holes are sequentially processed by the cutting tool.

According to a fourth aspect of the present invention, there is provided a drilling tool for drilling a workpiece having a plurality of holes concentrically along a central axis thereof, wherein a drill is provided on a shaft outer periphery, A guide portion is provided on the outer periphery of the tip end of the shaft portion, and the guide portion inserts the hole machining tool into the at least one machined hole at one end of the workpiece from the other end of the workpiece. And is slidably supported and diametrically expandable and contractible.

According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the guide portion is provided with a plurality of guide pads along the circumferential direction capable of moving back and forth in the diametrical direction from the outer periphery of the shaft tip. In the shaft portion corresponding to the guide pad, an extension mechanism for pressing the guide pad outward in the diametrical direction is provided.

According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the expansion mechanism includes a space communicating with a passage formed in the shaft, and expands when a fluid is supplied to the space. The configuration includes an elastic deformation body.

According to a seventh aspect of the present invention, in the configuration according to the fifth aspect of the present invention, a plurality of expansion mechanisms are arranged along the circumferential direction corresponding to the plurality of guide pads, and have a tapered inner surface. And a taper cone having a tapered tapered surface that matches the tapered surface of the inner surface of the collet. By moving the tapered cone back and forth, the guide pad is expanded and contracted through the collet.

According to an eighth aspect of the present invention, in the configuration of the seventh aspect, the taper cone is moved back and forth by a fluid pressure cylinder.

According to a ninth aspect of the present invention, in the configuration of the seventh aspect of the present invention, the tapered cone is moved back and forth by a wireless motor.

[0020]

According to the first aspect of the present invention, a guide for the tip of a drilling tool inserted into at least one processed hole at one end of a workpiece from the other end of the workpiece. The other part is supported by the hole machining tool, and the other hole is machined by the hole machining tool by moving the hole machining tool relative to the workpiece in a direction in which the guide portion approaches the other end of the workpiece. This eliminates the need for a dedicated guide bush for supporting the drilling tool, thereby preventing the deterioration of workability due to the mounting of the guide bush and the deterioration of workability when aligning the tool tip with the guide bush. Also, since the drilling tool is processed while being pulled relatively to the workpiece, the drilling tool has a larger bending stress than the processing performed while pressing relatively to the workpiece. Does not work, and high-precision drilling can be performed.

According to the second aspect of the present invention, a plurality of cutting tools are provided along the axial direction on the outer periphery of the shaft portion of the hole machining tool, and the guide portion is supported by the machined hole at one end. Since each hole of the workpiece corresponding to the plurality of cutting tools is simultaneously processed, the plurality of holes can be processed in a short time with high accuracy.

According to the third aspect of the present invention, one cutting tool is provided on the outer periphery of the shaft portion of the drilling tool, and the drilling tool is supported by the drilled hole while the guide portion is supported by the drilled hole. The hole adjacent to the machined hole is sequentially machined by the cutting tool by relative movement in the direction, so that the axial length of the workpiece can be set freely within the range of the axial length of the hole machining tool. Since the versatility is ensured and the amount of relative movement of the drilling tool with respect to the workpiece increases, the work of drilling while drilling the drilling tool becomes more effective.

According to the fourth aspect of the present invention, the cutting tool is provided on the outer periphery of the shaft, and the guide is provided on the outer periphery of the tip of the shaft.
The guide portion is slidably supported by inserting a hole machining tool from the other end of the workpiece into at least one machined hole at one end of the workpiece, and
Since it is possible to expand and contract in the diametrical direction, there is no need for a dedicated guide bush to support the hole drilling tool, and the workability is degraded by installing the guide bush and the work when aligning the tool tip with the guide bush. Sex deterioration can be prevented. In addition, since the drilling tool is machined while being pulled relatively to the workpiece, a larger bending stress is applied to the drilling tool as compared to the machining performed while pressing the workpiece relatively. And high-precision drilling can be performed.

According to the fifth aspect of the present invention, the guide portion is provided with a plurality of guide pads in the circumferential direction that can move forward and backward in the diametric direction from the outer periphery of the tip of the shaft portion. An expansion mechanism that presses the guide pad outward in the diameter direction is provided.By pressing the guide pad outward in the diameter direction using the expansion mechanism, the guide pad comes into close contact with the inner surface of the hole in the workpiece and the hole machining tool is processed. It can be easily supported by the already-formed hole.

According to the sixth aspect of the present invention, the expansion mechanism includes a space communicating with a passage formed in the shaft, and includes an elastic deformable body that expands when a fluid is supplied to the space. Therefore, by supplying the fluid to the space through the passage, the elastically deformable body expands and comes into close contact with the inner surface of the processed hole, so that the drilling tool can be easily supported by the processed hole.

According to the seventh aspect of the present invention, a plurality of expansion mechanisms are provided along the circumferential direction corresponding to the plurality of guide pads and have a tapered surface on the inner surface. And a taper cone having a tapered tapered surface to be aligned.By moving the taper cone back and forth, the guide pad is expanded and contracted through the collet, so that the guide is moved by moving the taper cone forward. The pad expands and comes into close contact with the inner surface of the processed hole, so that the hole processing tool can be easily supported by the processed hole.

According to the eighth aspect of the present invention, since the taper cone is moved back and forth by the hydraulic cylinder, the operation of the hydraulic cylinder causes the taper cone to move forward, and the guide pad expands to form the inner surface of the processed hole. Close contact can easily support the drilling tool in the drilled hole.

According to the ninth aspect of the present invention, since the taper cone is moved back and forth by the wireless motor, the taper cone is moved forward by the operation of the wireless motor, and the guide pad expands and is formed on the inner surface of the processed hole. Close contact can easily support the drilling tool in the drilled hole.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a process diagram of a drilling method showing an embodiment of the present invention, and FIG. 2 is a side view (cross section) of a drilling tool 15 used in the drilling method. A plurality of holes 17a to 17e are formed concentrically along the axial direction of the workpiece 17 to be machined by the hole machining tool 15, and the holes 17a to 17e are machined.
The workpiece 17 is, for example, a crankcase that rotatably supports a crankshaft of a multi-cylinder engine, a cylinder head that rotatably supports a camshaft, and the like.

The above-mentioned hole drilling tool 15 is provided with a plurality of cutting tools 21 on the outer periphery of the shaft portion 19.
The same portion in the circumferential direction on the outer periphery of the shaft portion 19 is provided at a predetermined interval in the axial direction. In this example, byte 2
1 are provided at equal intervals, but may be provided at different intervals. A base 23 at one end of the shaft portion 19 is attached to a main shaft of a four-axis control machining center (not shown).

A guide portion 25 is provided at the other end of the shaft portion 19 described above. FIG. 3 is an enlarged sectional view of the guide section 25 taken along the line AA. In the cylindrical section 27, four guide pads 29 are accommodated at equal intervals in the circumferential direction. The guide pad 29 includes an arc portion 29a having an arc surface concentric with the inner peripheral surface of the cylindrical portion 27, and a pad portion 29b projecting diametrically outward on the outer surface of the arc portion 29a at the center in the circumferential direction. And made of a super hard material such as a sintered alloy.

The pad portion 29b is inserted into a slit hole 27a formed at regular intervals in the circumferential direction in the cylindrical portion 27, and its tip projects out of the cylindrical portion 27.
9 is movable with respect to the cylindrical portion 27 in this protruding direction. A gap 31 is formed between the circular arc portions 29a adjacent in the circumferential direction.

As shown in FIG. 2, both ends in the axial direction of the pad portion 29b are provided with tapered portions 29c and 29d, and the left axial end portion of the tapered portion 29c and the right axial end portion of the tapered portion 29d are cylindrical. It forms substantially the same surface as the outer peripheral surface of the portion 27. Further, the pad portion 29 located at the upper part in FIG.
An abutment surface 29e is formed at both left and right boundaries between the b and the arc portion 29a. Correspondingly, an inner corner of the slit hole 27a of the cylindrical portion 27 is aligned with the abutment surface 29e. A chamfer 27c is provided.

The abutment surface 29e and the chamfer 27
c may be provided for all of the other three pad portions 29b.

FIG. 4 shows the inside of the guide pad 29.
The elastic deformation body 33 is accommodated as an expansion mechanism as shown in the side view. The elastically deformable body 33 is made of an elastically deformable material such as rubber, and has a space 35 formed therein. The space 35 is, as shown in FIG.
The center is communicated with the coolant channel 37 formed along the axial direction over the base 9 and the base 23. By supplying a coolant, which is a fluid, from a machining center (not shown) to the coolant passage 37, the elastically deformable body 33 expands, and presses the guide pad 29 to expand and move diametrically outward.

An air flow path different from the coolant flow path is formed in the shaft portion 19, and air is supplied to the space 35 through this air flow path, whereby the elastically deformable body 33 is similarly expanded. Can be.

Next, a method of drilling a workpiece 17 using the above-described drilling tool 15 will be described with reference to FIG.

First, as shown in FIG. 1 (a), using a normal boring tool 39, a hole 41 at one end of the work 17 is
Process 7e. At this time, the hole 17d may be processed in addition to the hole 17e. After the processing of the hole 17e, the workpiece 17 is turned left and right as shown in FIG.

Next, the boring tool 15 shown in FIG. 2 is mounted on a main shaft of a machining center (not shown) in place of the boring tool 39 used in FIG. The hole machining tool 15 is inserted into the inverted workpiece 17 through the hole 17a at the other end as shown in FIG. 1C, and the guide portion 25 at the tip is bored by the boring tool 39. Until the position corresponding to the processed hole 17e,
Move in the direction indicated by arrow B.

When the drilling tool 15 is inserted into the workpiece 17, no coolant is supplied to the coolant channel 37, and therefore, the elastically deformable body 33 in the guide 25 is not supplied.
3 is in a state of contracting inward as shown in FIG. 3, and the pad portion 29 b of the guide pad 29 is in a state of being retracted into the cylindrical portion 27. In this state, the cutting tool 21 is
In order not to interfere with the inner surfaces of
Is inserted with its axis shifted from the center of the holes 17a to 17e.

When the drilling tool 15 is inserted into the workpiece 17, the pad portion 29b is retracted into the cylindrical portion 27, and the pad portion 29b has tapered portions 29c and 29d shown in FIG. , So it is easy.

FIG. 1 shows that the guide portion 25 corresponds to the hole 17e.
When the coolant reaches the position shown in FIG.
The coolant is supplied to the guide portion 2
5, flows into the space 35 in the elastically deformable body 33,
The elastically deformed body 33 expanded by the above-described process is used for the guide pad 2.
9 is pressed outward in the diametrical direction to bring the tip end surface of the pad portion 29b into close contact with the inner peripheral surface of the hole 17e.

At this time, the pad portion 29 shown in FIG.
abutting surface 29 at both left and right boundary portions between b and arc portion 29a
e is aligned with the chamfer 27c at the inner corner of the slit hole 27a of the cylindrical portion 27. By this alignment, the guide pad 2
9 is avoided in the circumferential direction, and the guide pad 29
Position accuracy can be ensured even if is repeatedly extended.

In this state, the drilling tool 15 is moved relative to the workpiece 17 in the direction shown by the arrow C while rotating, as shown in FIG. Holes 17d, 17c, 17b, 17
a is processed simultaneously. At this time, the pad portion 29b slides in the axial direction while sliding and rotating with respect to the processed hole 17e. Thereby, a plurality of holes can be processed in a short time.

As described above, while the guide portion 25 is slidably supported in the processed hole 17e, the holes 17d, 17c, 1
Since the 7b and 17a are machined by the cutting tool 21, a dedicated guide bush for supporting the hole drilling tool 15 is not required, so that the workability is deteriorated by mounting the guide bush and the tool tip is aligned with the guide bush. Workability can be prevented from deteriorating.

Further, since the drilling tool 15 is machined while being pulled relatively to the workpiece 17, the drilling tool 1
No large bending stress is applied to the workpiece 5 as compared with the processing while the workpiece 17 is pressed relatively, and high-precision drilling is performed even if the material differs depending on the processing portion (hole). be able to.

FIG. 5 uses a tool provided with one cutting tool 21 in the vicinity of the guide portion 25 as the drilling tool 43. FIG. 5A shows a work process corresponding to FIG. 1C, and is the same as FIG. 1 up to this work process.

From the state shown in FIG. 5A, as shown in FIG. 1D, the relative movement with respect to the workpiece 17 in the direction of arrow C as shown in FIG. By doing so, the guide portion 25 is first supported by the processed hole 17e, and the hole 17d adjacent to the hole 17e is processed by the cutting tool 21. Subsequently, while the guide portion 25 is supported by the processed hole 17d, the hole 17c adjacent to the guide portion 25 is processed by the cutting tool 21. In this way, the guide portion 2 is inserted into the processed hole.
While supporting 5, holes adjacent to the processed holes are sequentially processed.

In this case, when moving the drilling tool 43 in the step of FIG. 5B, the guide portion 25 needs to have an axial length such that it is simultaneously supported by two adjacent drilled holes. It is.

In the example shown in FIG. 5, since the hole is formed by using one cutting tool 21, the tool length is not limited to the case where the length of the workpiece 17 in the axial direction is shorter than that shown in FIG. 1, the versatility is ensured, and the amount of movement of the drilling tool 43 is larger than that in the case of FIG.
The work of processing while pulling relative to is more effective.

FIG. 6 uses a collet 45 and a tapered cone 47 as an expansion mechanism for expanding the guide pad 29. FIG. 7 is a cross-sectional view similar to FIG. 3 when this expansion mechanism is used. Four collets 45 are provided at equal intervals in the circumferential direction, and the inside of a substantially circular cross section surrounded by the four collets 45 is shown. And a tapered surface 45a having a smaller diameter toward the distal end of the post-drilling tool 15, 43.

The tapered cone 47 accommodated in the four collets 45 has a tapered surface 47a corresponding to the tapered surface 45a and having a smaller diameter toward the distal end of the post-drilling tool 15, 43. In the shaft portion 19 at the rear end of the taper cone 47,
A drive cylinder 49, which is a fluid pressure cylinder for moving the taper cone 47 back and forth along the axial direction, is housed. The coolant pressure acts on the drive cylinder 49 via the coolant flow passage 37 in the shaft portion 19, so that the piston rod 5
The taper cone 47 advances through 1 and expands the guide pad 29 diametrically outward through the collet 45.

FIG. 8 shows an example in which a wireless motor 53 is used instead of the drive cylinder 49 in FIG. The drive of the wireless motor 53 is controlled by a controller 55,
When receiving the drive signal, the taper cone 4
7 is moved back and forth.

[Brief description of the drawings]

FIG. 1 is a process diagram of a hole drilling method showing an embodiment of the present invention.

FIG. 2 is a side view of a drilling tool used in the drilling method of FIG. 1;

FIG. 3 is an enlarged sectional view taken along line AA of FIG. 2;

FIG. 4 is a side view of an expansion mechanism housed inside the tip of the drilling tool of FIG. 3;

FIG. 5 is a process diagram of a hole drilling method using a tool provided with one cutting tool near a guide portion as a hole drilling tool.

FIG. 6 is a side sectional view showing an example in which a collet and a taper cone are used as an expansion mechanism.

FIG. 7 is a sectional view corresponding to FIG. 3 of the expansion mechanism of FIG. 6;

FIG. 8 is a side sectional view showing an example in which the taper cone of FIG. 6 is driven by a wireless motor.

FIG. 9 is a process diagram of a guide bush method as a conventional hole drilling method.

FIG. 10 is a process diagram of a guide bushless method as a conventional hole drilling method.

[Explanation of symbols]

 15, 43 hole machining tool 17 workpiece 17a, 17b, 17c, 17d, 17e hole 19 shaft portion 21 byte 25 guide portion 29 guide pad 33 elastic deformation body (expansion mechanism) 35 space section (expansion mechanism) 45 collet (expansion) Mechanism) 45a taper surface 47 taper cone (expansion mechanism) 47a taper surface 49 drive cylinder (fluid pressure cylinder) 53 wireless motor

Claims (9)

[Claims] 1. A drilling method for drilling a workpiece having a plurality of holes concentrically along its central axis, wherein at least one hole at one end of the workpiece is formed. After processing, from the other end of the workpiece, after inserting in a state where the guide portion at the tip of the hole processing tool is contracted in the diametrical direction, into the processed hole at the one end,
The guide portion is supported in a state of being expanded in the diametrical direction, and the drilling tool is relatively rotated with respect to the workpiece in a direction in which the guide portion approaches the other end of the workpiece while rotating. A hole drilling method, wherein another hole is drilled by the hole drilling tool. 2. A plurality of cutting tools are provided along the axial direction on the outer periphery of the shaft portion of the drilling tool. The plurality of cutting tools correspond to the plurality of cutting tools while supporting the guide portion in a processed hole at one end. 2. The hole machining method according to claim 1, wherein each hole of the workpiece is machined simultaneously. 3. A drill is provided on the outer periphery of a shaft portion of the drilling tool. The drilling tool is axially moved relative to a workpiece while the guide portion is supported by the drilled hole. 2. The hole machining method according to claim 1, wherein holes adjacent to the already completed holes are sequentially machined by the cutting tool. 4. A drilling tool for drilling a workpiece provided with a plurality of holes concentrically along a central axis thereof, wherein a drill is provided on an outer periphery of a shaft portion, and a tool is provided on an outer periphery of a tip end of the shaft portion. A guide portion, and the guide portion is slidable by inserting the hole drilling tool into at least one processed hole at one end of the workpiece from the other end of the workpiece. A hole machining tool supported by a hole and capable of expanding and contracting displacement in the diameter direction. 5. The guide portion is provided with a plurality of guide pads along the circumferential direction which are movable in a diametrical direction from the outer periphery of the tip of the shaft portion, and the guide pad is provided in the shaft portion corresponding to the guide pad. The drilling tool according to claim 4, further comprising an expansion mechanism for pressing outward. 6. The expansion mechanism includes a space communicating with a passage formed in the shaft, and an elastic deformation body that expands when a fluid is supplied to the space. 5. The drilling tool according to 5. 7. An expansion mechanism includes: a plurality of collets which are arranged along a circumferential direction corresponding to a plurality of guide pads and have a tapered surface on an inner surface; and a tapered tapered surface which matches the tapered surface of the inner surface of the collet. 6. The hole machining tool according to claim 5, further comprising a taper cone having the taper cone, and moving the taper cone back and forth to expand and contract the guide pad via the collet. 8. The drilling tool according to claim 7, wherein the taper cone is moved back and forth by a hydraulic cylinder. 9. The drilling tool according to claim 7, wherein the taper cone is moved back and forth by a wireless motor.