JP2003311517A - Processing method for internal surface of cylinder and processing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lessen machining allowance at low grinding-efficiency portions on the internal face of a cylinder in the process of honing, without extending the processing time. <P>SOLUTION: In a pneumatic/hydraulic pressure converter unit 29 within a processing head 13, pneumatic pressure is converted into hydraulic pressure, and by a power unit 45, on which the hydraulic pressure works, a transfer unit 57 of an elastic deformation portion 43 shifts to such a direction as to form an orthogonal angle with an axis, jointly with a boring bar 59, which is equipped with a roughing blade 61 and a finishing blade 63. In a state in which hydraulic pressure is applied to the power unit 45 so that the blade 61 is protruded toward the inner face of a cylinder bore 67, the processing head 13 is transferred in an outward movement within the cylinder bore 67, and roughing is thereby carried out. After completion of roughing, application of hydraulic pressure is once lifted, and subsequently, as hydraulic pressure application is resumed and gradually increased, and as the blade 63 is transferred from the inner face of the cylinder bore to the inner-radius direction, the blade is moved through the return course within the cylinder bore 67, and the opening portion on the other side of the cylinder bore is finish-machined into a taper shape. After taper processing, finish machining is implemented, with the hydraulic pressure kept at a constant level. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing an inner surface of a cylinder.

[0002]

2. Description of the Related Art Conventionally, as a method for processing the inner surface of a cylinder, there is one as shown in FIG. First, as shown in FIG. 8 (a), a fine boring method is applied to the inner surface of the cylinder bore 1 by rotatingly inserting a machining head 5 for boring, which has a cutting tool 3 at the tip, into the cylinder bore 1. Perform boring processing by. At this time, the processing head 5
In the figure, rough movement is performed by the outward movement downward, and finishing is performed by the return movement upward.

After the boring, the honing head 9 having the grindstone 7 on the outer periphery is rotated and reciprocated in the cylinder bore 1 to perform rough honing as shown in FIG. 8 (b). After that, finish honing is performed as shown in FIG.

Here, a crankshaft support portion 11 or the like is usually present below the cylinder bore 1 in the drawing, and in honing, the honing processing head 9 cannot be inserted deeply, and the crankshaft of the cylinder bore 1 cannot be inserted. The processing head 9 for honing is provided near the supporting portion 11 side.
The stroke of the reciprocating motion is insufficient, resulting in deterioration of machining efficiency.

Therefore, in order to make the machining diameter of the cylinder bore 1 uniform as a whole in the finish honing process of FIG. 8 (c), in the rough honing process of FIG. The amount of grinding here is larger than that of other portions by temporarily stopping the axial feeding operation and rotating only the vicinity of the support portion 11 side.

Further, in Japanese Unexamined Patent Publication No. 8-267353, in the boring process for the cylinder bore, the feed rate in the axial direction of the machining head in the vicinity of the lower end of the cylinder bore is made slower than in other parts, and grinding is performed near the lower end of the cylinder bore. A processing method is disclosed in which the amount of grinding is increased in comparison with other parts to reduce the grinding allowance during honing. As a result, the grinding allowance of a portion having poor processing efficiency in the subsequent honing processing is reduced.

[0007]

However, in the above-mentioned conventional method for machining the inner surface of the cylinder, the former method is used for a portion having poor machining efficiency in the finish honing.
Since the axial feed operation in rough honing is temporarily stopped and only rotation is performed, the processing time becomes longer, and with the latter as well, it is possible to reduce the machining efficiency in honing by boring. Since the feed rate is slowed, the processing time becomes long.

Therefore, an object of the present invention is to make it possible to reduce the stock removal of the grinding amount of the portion of the inner surface of the cylinder where the grinding efficiency is poor in the honing process without increasing the processing time.

[0009]

In order to achieve the above-mentioned object, the invention of claim 1 inserts a machining head for boring, which has a cutting tool at its tip, from one opening of a cylindrical member, At the time of the outward movement to move toward the other opening,
Rough machining the inner surface of the cylindrical member, and after the rough machining, the cutting tool is moved to the center of the machining head during the backward movement in which the machining head is moved from the other opening toward the one opening. This is a method of machining the inner surface of a cylinder by moving in a direction orthogonal to the axis away from the inner surface of the cylindrical member and performing finishing so that the other opening side has a large diameter.

According to a second aspect of the present invention, in the method for machining the inner surface of the cylinder according to the first aspect, the cylindrical member is an engine cylinder bore, and the other opening side of the cylinder bore having a large diameter by the finishing process is It is on the crankcase side, and after the finishing, the inner surface of the cylinder bore is subjected to honing.

According to a third aspect of the present invention, in the method for machining the inner surface of a cylinder according to the first or second aspect, the inner surface of the cylindrical member is tapered so that the other opening side has a larger diameter toward the end thereof. It is intended to be processed.

According to a fourth aspect of the present invention, in the method for machining the inner surface of the cylinder according to the third aspect, pressure is applied to the machining head in a direction orthogonal to the central axis thereof,
An elastically deformable portion that moves and deforms in the same direction, the cutting tool,
As the pressure applied to the elastically deformable portion increases, the elastically deformable portion moves away from the inner surface of the cylindrical member.

According to a fifth aspect of the present invention, in the method for machining the inner surface of the cylinder according to the fourth aspect, the machining head has a cutting tool for roughing and a cutting tool for finishing at positions facing each other on the outer peripheral portion. Provided, with a predetermined pressure applied to the elastically deforming portion, in a state in which the cutting tool for roughing is projected toward the inner surface of the cylindrical member, roughing is performed by moving the processing head in the cylindrical member in the forward path, In the return movement after the completion of the rough machining, after releasing the predetermined pressure, the pressure applied to the elastically deforming portion is gradually increased and the cutting tool for finishing is separated from the inner surface of the cylindrical member. In this case, the cylindrical member is moved inward in the radial direction to finish the other opening side of the cylindrical member into a tapered shape.

According to the invention of claim 6, a cutting tool for roughing and a cutting tool for finishing are provided at positions facing each other on the outer circumference of the tip of the processing head for boring.
In the direction orthogonal to the central axis of the processing head, and by applying pressure in the direction from the cutting tool for finishing to the cutting tool for roughing, the cutting tools move in the same direction and move in the same direction. An elastically deformable portion for moving to is provided.

According to a seventh aspect of the present invention, in the configuration of the sixth aspect of the invention, in the initial state in which the elastically deforming portion is not applied with pressure, the roughing cutting tool includes a machining head and a cylindrical member. With the central axes aligned with each other, they are located radially inward with respect to the inner surface of the cylindrical member before roughing, while the cutting tool for finishing is radially outer than the inner surface of the cylindrical member after roughing. It is located as a structure.

[0016]

According to the first aspect of the present invention, when the machining head for boring is reciprocated and the finishing process is performed by the backward movement, the cutting tool is moved to the inner surface of the cylindrical member with respect to the central axis of the machining head. Since it is moved in the direction away from, it is necessary to temporarily stop the feed operation in the axial direction of the machining head or slow the feed speed when increasing the amount of machining in the axial direction on the inner surface of the cylinder. Since it does not exist, the processing time can be shortened.

According to the second aspect of the present invention, even if the crankcase side of the cylinder bore is a portion where the machining efficiency is poor due to the honing after the boring, the machining amount by the boring is increased. Therefore, in the honing process after the boring process, the inner diameter of the inner surface of the cylinder bore can be made uniform over the entire length.

According to the third aspect of the invention, even if the crankcase side of the cylinder bore is a portion where the machining efficiency due to honing after boring is poor, this portion has a tapered shape with a larger diameter toward the opening end side. Therefore, in the honing process after the boring process, the inner diameter of the cylinder bore can be more surely made uniform over the entire length.

According to the invention of claim 4, the cutting tool provided on the machining head moves in a direction away from the inner surface of the cylinder as the pressure applied to the elastically deforming portion increases, so that the applied pressure is reduced. Compared with the case, the diameter of the taper shape can be controlled with high accuracy.

According to the invention of claim 5, roughing is performed by moving the working head for boring processing in the forward path while applying a predetermined pressure to the elastically deformable portion, and subsequently, the roughing is performed. When performing the finishing process by making the other end side of the opening side taper by moving in the backward direction, the cutting tool for finishing is moved to the outside in the radial direction while increasing the pressure applied to the elastically deforming part. As compared with the case where the applied pressure is reduced, it is possible to control the processing diameter of the tapered shape with high accuracy.

According to the invention of claim 6, the pressure is applied to the elastically deformable portion to move the roughing cutting tool outward in the radial direction, and the processing head for boring is moved forward. After performing the roughing process and releasing the above-mentioned pressure application, while increasing the pressure to be applied again, while moving the cutting tool for finishing from the radially outer position toward the inner position,
Since the machining head can be moved back and the other end on the opening side can be finished into a taper shape, the diameter of the taper shape can be reduced compared to when tapering while reducing the pressure applied to the elastically deforming part. Can be controlled with high precision.

According to the invention of claim 7, by applying pressure to the elastically deformed portion in the initial state, the roughing cutting tool moves radially outward with respect to the inner surface of the cylindrical member. Rough machining can be performed by moving the machining head in the forward direction in the state, and after the rough machining, the pressure application is released and the pressure is applied again Since the inner surface of the member moves from the outer side position toward the inner side position in the radial direction, the tapered head can be easily machined by moving the machining head in the return path in the course of this movement.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a machining head 13 for boring, showing an embodiment of the present invention. The machining head 13 is used by being mounted on a main shaft 16 protruding from a lower end of a housing 15 in a machine tool (for example, a machining center) as shown in FIG. The main shaft 16 is rotatably accommodated in the housing 15 in a vertically extended state, and includes a tool holder having an ATC shank at its lower end. The processing head 13 described above is removably attached to the tool holder.

With the above-mentioned machine tool, the work support 17
After rough machining is performed on the inner surface of the cylinder bore of a cylinder block (not shown) as a cylindrical member fixed on the upper side while the machining head 13 is rotating, the rough movement is performed by the outward movement downward in the figure, and then the upward movement in the figure is performed. Finish processing with.

As shown in FIG. 1, the boring head 13 for boring has a shank portion 19 mounted on the tool holder of the main shaft 16, and the shank portion 19 has a vertical direction in FIG. An air passage 21 is formed in the. The upper end of the air passage 21 communicates with an air passage provided in the main shaft 16, and the air passage in the main shaft 16 is rotatable with respect to the upper end of the main shaft 16 as shown in FIG. The rotary joint 23 fixed to the upper part is connected to an air controller 27 via an air pipe 25. That is, the processing head 1 is controlled by the air controller 27.
The air pressure of the air passage 21 in the shank portion 19 in 3 is controlled.

A shank portion 1 below the air passage 21.
An air-hydraulic pressure converting portion 29 is provided in the body portion 28 continuous with 9. The air-hydraulic pressure conversion unit 29 includes the first cylinder 3
A first piston 33 is accommodated in the first movable unit 1 via a sliding seal 34 so as to be movable in the vertical direction in the figure, and a second piston 37 is connected to a lower portion of the first piston 33 via a connecting rod 35. This second piston 37 corresponds to the first cylinder 3
It is accommodated in a small-diameter second cylinder 39 communicating with the lower part of 1 via a sliding seal 40 so as to be vertically movable.

A lower portion of the second piston 37 serves as a working oil space 42 filled with working oil, and air pressure acts on the first piston 33 through the air passage 21 to provide the first piston 33.
The piston 33 descends, and the second piston 37 descends accordingly, so that the hydraulic pressure in the hydraulic fluid space 42 is increased.

A communication passage 41 communicates with the lower portion of the hydraulic oil space 42 and is formed in the body portion 28. The communication passage 41 is formed over an elastically deformable portion 43 fixed to the lower end of the body portion 28. Has been done. A power unit 45 is provided inside the elastically deformable portion 43. In the power unit 45, a hydraulic space 51 is formed between the convex block 47 and the concave block 49, and the hydraulic space 51 and the communication passage 41 described above are elastically deformable 43 and the concave block 4.
It communicates with the oil passage 53 formed in 9.

The elastically deforming portion 43 has an S-shaped slit 55.
Is formed, and when hydraulic pressure acts on the hydraulic space 51,
The lower moving portion 57 of the elastically deforming portion 43 shifts leftward in FIG. A boring bar 59 is attached to the lower part of the moving part 57, and a cutting tool 61 for roughing and a cutting tool 63 for finishing are attached to the lower parts of the boring bar 59 on both sides in the left-right direction in FIG. ing.

Therefore, by the air controller 27 shown in FIG. 2, the air passage 21 shown in FIG.
When the air pressure is supplied to the inside, the first piston 33 descends,
Along with this, the second piston 37 also descends, and the hydraulic oil space 4
The hydraulic pressure in 2 increases, the hydraulic pressure acts on the hydraulic space 51 in the power unit 45 communicating with the hydraulic oil space 42, and the moving portion 57 shifts leftward in FIG. 1 together with the cutting tools 61 and 63 at the tip of the boring bar 59. The elastically deforming portion 43 elastically deforms so as to perform.

FIG. 3 shows a state in which hydraulic pressure acts on the power unit 45, the elastically deforming portion 43 elastically deforms, and the moving portion 57 shifts leftward in the drawing.

Boring bar 59 and elastic deformation portion 43
Has a cylindrical shape with substantially the same outer diameter, is inserted into the cylinder bore 67 of the cylinder block 65, and bores the inner surface of the cylinder bore 67 with the above-described cutting tools 61, 63.

FIG. 4 schematically shows the positional relationship between the cutting tools 61 and 63 with respect to the central axis S of the processing head 13. Note that, in FIG. 4, components such as the power unit 45 are shown in a simplified manner with respect to FIG.

FIG. 4A shows an initial state in which hydraulic pressure is not acting on the power unit 45. At this time, the roughing cutting tool 61 is attached to the boring bar 59 in a state of being located radially inward of the finishing processing cutting tool 63 with respect to the central axis S of the processing head 13 and orthogonal to the axis. .

That is, in this initial state, the processing head 13
The diameter of the circle of rotation trajectory at the tip of the blade 61 when the tool rotates is smaller than the diameter of the circle of rotation trajectory at the tip of the blade 63. Specifically, for example, the former diameter is 85.00 mm
The diameter of the latter is 86.00 mm. The center line K between the outer peripheral ends of the two cutting tools 61, 63 in this state
Is closer to the right side by 150 μm with respect to the central axis S of the processing head 13.

FIG. 4 (b) shows a case of rough machining. At this time, the maximum hydraulic pressure acts on the power unit 45 to maximize the amount of deformation of the elastically deforming portion 43, and the moving portion 57 in the left side of the drawing. The amount of shift in the direction is the maximum.

At this time, the rough-edging tool 61 is located outside the finishing tool 63 with respect to the central axis S of the processing head 13 in the radial direction orthogonal to the axis. Specifically, the cutting tool 6 when the processing head 13 rotates
The diameter of the rotation locus circle at the tip of 1 is 85.70 mm, and the cutting tool 6
The same diameter of 3 is 85.30 mm.

In this state, the center line K between the outer peripheral side tips of the two cutting tools 61, 63 is offset by 200 μm to the left with respect to the center axis line S of the machining head 13. Therefore, at the time of rough machining in FIG. 4B, the center line K is 350 μm (1
50 μm + 200 μm) (shifted) (because the blades 61 and 63 are shown in diameter, 3
50 μm × 2 = 700 μm deviation. ).

With the state shown in FIG.
When the tool moves 6 times while moving downward while rotating
1, rough machining is performed on the cylinder bore 67. At this time, the cutting tool 63 for finishing does not come into contact with the cylinder bore 67 because of the relationship of the circle of the rotation locus described above.

FIG. 4 (c) shows the finish processing.
At this time, the hydraulic pressure lower than the maximum hydraulic pressure in FIG. 4B acts on the power unit 45, and the deformation amount of the elastic deformation portion 43 becomes smaller than that in FIG. 4B, and accordingly, the moving portion 57. Similarly, the shift amount of becomes smaller.

At this time, the finishing tool 63 has a rough cutting tool 61 with respect to the central axis S of the working head 13.
Is located on the outer side in the radial direction orthogonal to the axis. For example, the cutting tool 61 when the processing head 13 rotates
The diameter of the circle of the rotation locus of the tip is 85.30 mm, and the blade 63
Has the same diameter of 85.70 mm. The center line K between the outer peripheral ends of the two cutting tools 61, 63 in this state coincides with the center axis line S of the processing head 13.

FIG. 5 is an explanatory view showing the operation when the roughing and finishing are performed on the cylinder bore 67 by using the above-mentioned processing head 13. In FIG. 5 (a), the position P of the end portion on the right side in the figure corresponds to the initial state of FIG. 4 (a), and the position Q of the end portion on the left side thereof is during rough machining in FIG. 4 (b). Equivalent to. The numerical value between the position P and the position Q is shown in FIG.
Shift amount of the moving unit 57 from the initial state of (a) (μm)
Is shown.

Next, the operation will be described. First, from the position P in FIG. 5, that is, the initial state of FIG.
As shown in (b), as a “rough machining shift”, FIG.
Each cutting tool 6 so as to be in the rough machining (position Q in FIG. 5) of (b)
1, 63 is shifted by the maximum amount (350 μm).

In this state, the machining head 13 is inserted into the cylinder bore 67 while rotating, and by the outward movement in the insertion direction, the inner surface of the cylinder bore 67 is roughly machined by the cutting tool 61 as "rough machining".

After completion of the rough machining, when the respective cutting tools 61, 63 move further downward from the opening side of the lower side in FIG. 1 opposite to the insertion side of the cylinder bore 67, "rough machining shift release" is carried out, It returns to the initial state (position P) in FIG. In this initial state, when the machining head 13 is rotated, the diameter (86.00 mm) of the rotation locus circle of the cutting tool 63 for finish machining is the cutting tool 6 for rough machining during rough machining.
The diameter of the circle of the same rotation locus 1 (85.70 mm), that is, larger than the inner diameter of the cylinder bore 67 after rough machining.

Therefore, in this state, the rotating machining head 13 is raised (returned) in the cylinder bore 67, whereby the inner surface of the cylinder bore 67 can be finished.

At the time of this finishing process, as a "finishing shift", each of the cutting tools 61 and 63 is about 130 μm in FIG.
Shift from the state of (a) to the left. Then, from this state, the machining head 13 is rotated and raised, and the shift amount is gradually increased while the shift amount is 150
Until it becomes μm, that is, until the state of FIG.
Part of the finishing process is performed as "tapering".

Finishing while increasing the shift amount is performed near the lower opening side end of the cylinder bore 67 in FIG. 1, and the vicinity of the opening side end is as shown in FIG. The lower side is processed into a taper portion 67a having a large diameter.

Following the above "taper processing", FIG.
In the state of (c), the machining head 13 is rotated and raised to perform "finishing" on the remaining upper side of the cylinder bore 67. At this time, the position of the cutting edge of the cutting tool 63 for finishing is set to the cutting tool 61 for roughing.
Since it is located radially outward of the blade edge of
Finishing is performed as desired on the inner surface of the roughened cylinder bore 67 processed by.

Incidentally, "tool wear correction" in FIG. 5 (b)
Indicates a correction shift amount region due to wear of the finishing blade 63. At the time of finishing, it is necessary to reduce the shift amount due to the wear of the cutting tool 63 and make the amount of protrusion of the cutting tool 63 outward in the radial direction equal to that before the wear. Therefore, the correction shift region described above is provided. The shift amount of 50 μm is the maximum wear correction.

By the way, as shown in FIG. 8, a crankshaft supporting portion 11 or the like is usually present in the crankcase below the cylinder bore 1 in the drawing, and in the honing process after the boring process, the honing process is performed. The machining head 9 cannot be inserted deeply, and the stroke of the reciprocating motion of the honing machining head 9 is insufficient near the crankshaft support portion 11 side of the cylinder bore 1, resulting in deterioration of machining efficiency.

However, the amount of machining near the opening on the lower side of the cylinder bore 67 in boring is as shown in FIG. Even if the stroke of the reciprocating motion of the honing processing head 9 is insufficient near the crankshaft support portion 11 side by making the taper shape larger than other portions,
The machining diameter can be made uniform over the entire length of the cylinder bore 67.

In the above-mentioned "tapering", the feeding operation of the machining head 13 is not temporarily stopped or the feeding speed is not slowed down, but the boring bar 59 is shifted in the diameter direction. It is not shortened, but shortened.

Further, in the above-mentioned "during taper processing",
While increasing the shift amount, that is, the air controller 2
The air pressure is controlled in the increasing direction by 7 and the power unit 4
The hydraulic pressure in 5 is increased.

Here, when the shift amount is changed, the first piston 33 and the second piston 37 in FIG. 1 move up and down, respectively. At this time, the pistons 33, 37 are moved.
Stick slips (friction) occur between the sliding seals 34, 40 on the outer periphery and the sliding surfaces. In order to stabilize the effect of this stick-slip, each piston 3
It is important to move while continuously applying pressure to 3,37.

On the contrary, when the pistons 33, 37 are moved while being decompressed, the stick-slip described above works in the opposite direction and the indicated value of the correction air pressure amount gradually decreases with respect to the cutting feed amount. However, it becomes an intermittent operation, and the shape of the processed hole becomes a step shape, and a smooth tapered shape cannot be obtained. Further, the intermittent action of stick-slip and the gradual reduction action of the correction air pressure are overlapped with each other, a dead zone in which control is not performed well is formed, and the shape of the processed hole becomes unstable.

On the other hand, in the processing while gradually increasing the correction air pressure, even if the stick slip is the same, during the shift operation, the stick slip continuously works in a constant amount and gradually increases, The hole shape becomes stable.

Therefore, in the above-described embodiment, during the "taper machining", the shift amount is increased, that is, the air pressure is controlled in the increasing direction by the air controller 27 and the hydraulic pressure in the power unit 45 is increased. Therefore, the tapered shape in the cylinder bore 67 becomes smooth and stable, and the machining diameter can be controlled with high accuracy.

In FIG. 6, a: b is a taper ratio. This taper ratio is an increase value of the correction air amount with respect to the feed amount or the rotation amount of the machining head 13 during taper machining. , The air controller 2 as the taper machining instruction value
It depends on whether to send to 7.

The correction air amount is sequentially increased by sending a pulse signal for taper machining to the air controller 27. This is a method of sending a pulse accompanying the rotation of the spindle of the machine tool to the air controller 27, or a machining operation. There are a method of feeding the amount of feed slide of the main shaft of the machine in a pulse form, a method of designating only the start point and the end point of the pulse and forming the pulse by the air controller 27 by itself.

In FIG. 7, instead of the tapered portion 67a of FIG.
The step portion 67b having a larger diameter than the other parts on the upper side is formed by finishing. Also in this case, when the processing head 13 of FIG.
In the state of (b), the same rough machining is performed by the cutting tool 61.

At the time of the subsequent return movement, "" in FIG.
"Finishing shift" is performed, and in this state, the step portion 67b is processed instead of "tapering" without changing the shift amount. After that, the shift amount is set to a state corresponding to the “finishing process” in FIG. 5B, and the same process as the “finishing process” is performed. Also in this case, the machining of the step 67b instead of the "taper machining" does not temporarily stop the feeding operation of the machining head 13 or slow the feeding speed, so that the machining time does not become long, It will be shortened.

Further, in processing the stepped portion 67b described above, the air controller 27 is operated while increasing the shift amount.
The air pressure is controlled in the increasing direction by the power unit 45
Since the hydraulic pressure in the cylinder is increased, the shape of the step 67b in the cylinder bore 67 becomes smooth and stable, and the machining diameter can be controlled with high accuracy.

In the above-described embodiment, the two cutting tools mounted on the boring bar 59 are the roughing cutting tool 61 and the finishing cutting tool 63, but only the finishing cutting tool 63 is used. However, the tapered portion 67a and the stepped portion 67b can be processed by appropriately adjusting the shift amount.

[Brief description of drawings]

FIG. 1 is a sectional view of a machining head for boring, showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an entire machine tool in which the machining head of FIG. 1 is used.

3 is an operation explanatory view showing a state in which hydraulic pressure is applied to a power unit in the processing head of FIG. 1, an elastically deforming portion is elastically deformed, and a moving portion is shifted.

4A and 4B are schematic diagrams showing the positional relationship of the cutting tool with respect to the central axis of the machining head shown in FIG. 1, where FIG. 4A is an initial state in which hydraulic pressure is not acting on the power unit, and FIG. c) is a state at the time of finishing.

FIG. 5 is an explanatory diagram showing an operation when rough machining and finishing are performed on a cylinder bore using a machining head.

FIG. 6 is a cross-sectional view of a cylinder bore whose lower portion is processed into a large-diameter tapered portion.

FIG. 7 is a cross-sectional view of a cylinder bore whose lower side is processed into a stepped portion having a large diameter.

FIG. 8 is an operation explanatory view showing a conventional method for processing the inner surface of a cylinder, (a) is boring, (b) is rough honing,
(C) is a finishing honing process.

[Explanation of symbols]

13 Processing head 43 Elastic deformation part 61 Cutting tool for rough machining 63 Cutting tools for finishing 65 Cylinder block (Cylindrical member) 67 cylinder bore 67a Tapered part S central axis

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masao Suzuki             Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan             Inside the automobile corporation (72) Inventor ▲ Taka ▼ Kazuhiko Shima             Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan             Inside the automobile corporation F-term (reference) 3C036 AA00 BB04 BB08                 3C046 LL02                 3C058 AA03 CB03

Claims (7)

[Claims] 1. A boring head for boring, which is provided with a cutting tool at its tip, is inserted from one opening of a cylindrical member, and is moved toward the other opening. Rough machining the inner surface, and after this rough machining, during the backward movement in which the machining head is moved from the other opening toward the one opening, the cutting tool is orthogonal to the central axis of the machining head. In a direction away from the inner surface of the cylindrical member, and finishing processing is performed so that the other opening side has a large diameter. 2. The cylinder member is a cylinder bore of an engine, the other opening side of the cylinder bore having a larger diameter by the finishing is a crankcase side, and the inner surface of the cylinder bore is subjected to honing after the finishing. The method for processing an inner surface of a cylinder according to claim 1, wherein: 3. The machining of the inner surface of the cylindrical member according to claim 1, wherein the inner surface of the cylindrical member is processed so that the other opening side has a taper shape with a diameter increasing toward the end thereof. Method. 4. The processing head includes an elastically deformable portion that is moved and deformed in the same direction when pressure is applied in a direction orthogonal to the central axis of the processing head, and the cutting tool is provided with an elastically deformable portion. The method for processing an inner surface of a cylinder according to claim 3, wherein the inner surface of the cylinder moves in a direction away from the inner surface of the cylinder member as the pressure is increased. 5. The machining head includes a cutting tool for roughing and a cutting tool for finishing, which are provided at positions facing each other on an outer peripheral portion, and apply a predetermined pressure to the elastically deforming portion for roughing. With the cutting tool of is protruding toward the inner surface of the cylindrical member,
Rough machining is performed by moving the machining head in the forward direction in the cylindrical member, and in the backward movement after the completion of the rough machining, after the predetermined pressure application is released, the pressure applied to the elastically deforming portion is gradually increased. The cutting tool for finishing is moved toward the inner side in the radial direction so as to be separated from the inner surface of the cylindrical member while increasing the number, and the other opening side of the cylindrical member is finished to be tapered. Item 4. The method for processing an inner surface of a cylinder according to Item 4. 6. A cutting tool for roughing and a cutting tool for finishing are provided at positions facing each other on the outer periphery of the tip of a processing head for boring, respectively, and in a direction orthogonal to the central axis of the processing head. And, by applying pressure in the direction from the cutting tool for finishing to the cutting tool for roughing, an elastic deformation portion for moving and deforming each cutting tool in the same direction while being deformed in the same direction is provided. Characterizing machine for cylindrical inner surface. 7. The elastically deformable portion, in an initial state where no pressure is applied, in a state in which the cutting tool for roughing processing has respective center axes of the processing head and the cylindrical member aligned with each other, before roughing processing. 7. The cutting tool for finishing is positioned radially inward of the inner surface of the cylindrical member, while being positioned radially outward of the inner surface of the cylindrical member after roughing. Of the inner surface of the cylinder.