JP4576069B2 - Multi-hole machining method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of machining a plurality of holes arranged at the same pitch, such as a cylinder bore of a cylinder block of an internal combustion engine, for example, and a boring apparatus used for carrying out this machining method.
[0002]
[Prior art]
For example, when machining a cylinder bore of a cylinder block of an in-line 4-cylinder internal combustion engine, conventionally, a boring machine as shown in FIGS. 1 and 2 is used, and machining is performed according to an operation cycle as shown in FIG. I was going. First, this prior art will be described. This boring apparatus constitutes one processing station of a transfer machine. A spindle head 13 is guided and supported by a head base 12 fixed to the front surface of a column 11 standing and fixed on a base 10 so as to be movable up and down. The servo motor 14 is moved up and down via the feed mechanism 15. A pair of tool spindles 17A, 17B parallel to and perpendicular to the spindle head 13 is parallel to the paper surface of FIG. 2 at a pitch twice that of the cylinder bores (holes) Wa1 to Wa4 of the cylinder block (workpiece) W. It is arranged in the direction and is driven to rotate by the spindle motor 18 through a gear box 13 a provided in the spindle head 13. On the jig table 23 of the jig unit 20 supported by the base 10 via the support beam 21, the cylinder block W is carried from the previous processing station by the transfer bar 25 extending in parallel with the paper surface of FIG. Is done. The jig table 23 is movable in a horizontal direction parallel to the paper surface of FIG.
[0003]
In this prior art, a quill mounted on the lower ends of the respective tool spindles 17A and 17B and machining the cylinder bores Wa1 to Wa4 of the cylinder block W includes an intermediate finishing blade and a fine finishing blade. The precision finishing tool is configured to advance and retract in the radial direction so that the turning radius of the cutting edge changes between a predetermined precision finishing turning radius and a smaller turning radius. The turning radius of the cutting edge of the semi-finished cutting tool fixed to the quill at the front side position is a constant value that is between the fine finishing turning radius of the fine finishing tool and the reduced turning radius.
[0004]
Next, the operation will be described with reference to FIG. First, in step k of FIG. 8, the processed cylinder block W is unloaded, the unprocessed cylinder block W is loaded and clamped to the jig table 23, and the jig table 23 is moved in the horizontal direction to move the cylinder block. W is indexed to the position where the first and third bores Wa1, Wa3 are coaxial with the quills 30A, 30B, and the precision finishing blade is retracted in the radial direction so that the turning radius of the cutting edge is smaller than the turning radius of the intermediate finishing machining. Each of the tool spindles 17A and 17B is rotationally driven by the spindle motor 18. In this state, the servo motor 14 is actuated to lower the spindle head 13, and the tool spindles 17A, 17B equipped with the quills 30A, 30B are first fast-forwarded to approach the cylinder block W, and then cylinders are moved at a predetermined lowering speed. Advancing (lowering) toward the block W, and intermediate finishing of the first and third bores Wa1, Wa3 is performed by each of the intermediate finishing tools (see step l). Next, the precision finishing blade is advanced in the radial direction to set the rotational radius of the blade edge to the precision finishing processing rotation radius (see step m), and the tool spindles 17A and 17B are moved backward to make the first and third bores Wa1 by the precision finishing blade. , Wa3 is precisely finished (see step n).
[0005]
After this fine finishing, the tool spindles 17A and 17B are quickly returned and retracted to predetermined positions, and then the jig table 23 is moved in the same manner as in step k described above to move the second and fourth bores of the cylinder block W. Wa2 and Wa4 are indexed to positions that are coaxial with the quills 30A and 30B, and the precision finishing blade is retracted in the radial direction (see step o), and then the tool spindles 17A and 17B are brought close to the cylinder block W by rapid traverse. Then, it is advanced at a predetermined lowering speed, and the intermediate finishing of the second and fourth bores Wa2 and Wa4 is performed by each of the intermediate finishing tools (see step p). Next, the precision finishing blade is advanced in the radial direction in the same manner as in step m described above (see step q), and then the tool spindles 17A and 17B are retracted and the second and fourth bores Wa2 and Wa4 are moved by the precision finishing blade. Fine finishing is performed (see step r). Then, each tool spindle 17A, 17B is quickly returned to a predetermined position and returned to the first step k.
[0006]
In the above-described example, each of the bores Wa1 to Wa4 is rough-finished in advance, but each quill 30A, 30B has a rotational radius of the blade edge smaller than the intermediate finishing processing rotational radius and is positioned forward of the intermediate finishing tool in the forward direction. A rough finish cutting tool may be further provided, and the rough finish processing may be performed simultaneously with the intermediate finish processing.
[0007]
[Problems to be solved by the invention]
According to the above-described conventional processing method, the rigid cylinder block W can be processed without any particular problem. Recently, however, the use of aluminum die-cast cylinder blocks with thinner cylinder blocks or cast bore liners has been adopted for weight reduction, etc., which reduces the rigidity around the cylinder bores. There is a problem that the processing accuracy cannot be ensured by this method.
In other words, the first and third bores Wa1 and Wa3 are once finished to a predetermined accuracy by intermediate finishing and fine finishing, but the subsequent intermediate finishing and second and fourth bores Wa2 and Wa4 and There is a problem that the finishing accuracy of the first and third bores Wa1 and Wa3 is lowered due to the residual distortion caused by the fine finishing, particularly the intermediate finishing with a large depth of cut. The present invention aims to solve such problems.
[0008]
[Means for Solving the Problems]
To this end, the method for processing a plurality of holes according to the present invention is as described in claim 1,
A method of machining a plurality of holes arranged in parallel with each other at the same pitch on a single work, and arranged in parallel with each other at an integer number of the number of holes and an integer multiple of the hole pitch. In a multi-hole machining method in which a semi-finished blade and a finely-finished blade that rotate together around a rotation axis are moved in the direction of the rotation axis, and the blade is sequentially inserted into a non-machined hole.
In the semi-finishing of each hole, the cutting edge of the semi-finishing tool is set to a predetermined turning radius and the turning radius of the fine finishing tool is set to be smaller than the turning radius of the finishing tool. Performed by multiple semi-finishing processes that sequentially advance into the processing hole,
Immediately after the semi-finishing process except the last, each cutting tool is retracted in the axial direction by setting the turning radius of each cutting edge to be smaller than the turning radius of the finishing work,
The fine finishing of each hole is performed by setting the turning radius of the cutting edge of the fine finishing tool to a predetermined fine finishing turning radius that is larger than that of the intermediate finishing turning radius immediately after the end of the final finishing process. In the fine finishing process, first, the hole that was finally finished in the middle finish process was performed, and for each hole that was finished in the middle finishing process except the last, the turning radius of each cutting edge of each cutting tool was made smaller than the turning radius of the finishing work. Performed by a fine finishing process in which the turning radius of the cutting edge of the precision finishing tool is retracted in the axial direction as the precision turning rotational radius after being advanced into each hole.
It is characterized by this.
[0009]
According to a first aspect of the present invention, the workpiece is a cylinder block of an internal combustion engine, and the plurality of holes is an even number of four or more evenly arranged. A cylinder bore is preferred.
[0010]
In the processing method for a plurality of holes according to claim 1 or 2, the cutting tool is retracted immediately after the intermediate finishing process except the last, as in claim 3, and the cutting is performed by fast reverse, and the last is excluded. It is preferable to insert each cutting tool prior to the fine finishing step for each hole that has been semi-finished in the finishing step by rapid feed.
[0011]
The method for processing a plurality of holes according to any one of claims 1 to 3 is such that, as described in claim 4, the multi-hole machining method rotates together with each cutting tool about each rotation axis, and the turning radius of the cutting edge is medium. It is preferable that rough finishing of a hole is also performed in the intermediate finishing step by using a rough finishing blade that is smaller than the finishing turning radius and is located forward of the intermediate finishing blade in the forward direction.
[0012]
The method for machining a plurality of holes according to any one of claims 1 to 4, wherein the pitch of the rotation axis is twice the pitch of the plurality of holes, as in claim 5. The number of holes is preferably half the number of holes.
[0018]
Further, according to the method for processing a plurality of holes according to the present invention, as described in claim 11,
A method of machining a plurality of holes aligned in parallel with each other in a workpiece, wherein a semi-finished blade and a fine-finished blade that rotate together around one rotation axis are moved in the direction of the rotation axis. In the cutting method of multiple holes that insert and process sequentially into unprocessed holes in the cutting tool,
In the semi-finishing of each hole, the cutting edge of the semi-finishing tool is set to a predetermined turning radius and the turning radius of the fine finishing tool is set to be smaller than the turning radius of the finishing tool. Performed by multiple semi-finishing processes that sequentially advance into the processing hole,
Immediately after the semi-finishing process except the last, each cutting tool is retracted in the axial direction by setting the turning radius of each cutting edge to be smaller than the turning radius of the finishing work,
The fine finishing of each hole is performed by setting the turning radius of the cutting edge of the fine finishing tool to a predetermined fine finishing turning radius that is larger than that of the intermediate finishing turning radius immediately after the end of the final finishing process. In the fine finishing process, first, the hole that was finally finished in the middle finish process was performed, and for each hole that was finished in the middle finishing process except the last, the turning radius of each cutting edge of each cutting tool was made smaller than the turning radius of the finishing work. Performed by a fine finishing process in which the turning radius of the cutting edge of the precision finishing tool is retracted in the axial direction as the precision turning rotational radius after being advanced into each hole.
You may do it.
[0020]
The method of machining a plurality of holes according to the present invention according to the embodiment shown in FIGS. Legal Explain. In this embodiment, the present invention is applied to machining of a cylinder bore of a cylinder block of an in-line four-cylinder internal combustion engine.
[0021]
First, the boring apparatus used in this embodiment will be described. This in The boring apparatus is substantially the same as that described in the above-described prior art except for devices for operating the quills 30A and 30B and the cutting tools 41 and 46, and the base 10, the column 11, the head base 12, and the head base. A spindle head 13 is provided that is guided and supported by 12 and is vertically moved by a servo motor 14 via a feed mechanism 15. A pair of tool spindles 17A, 17B having a rotation axis parallel and perpendicular to each other in the spindle head 13 has a pitch twice the pitch of the cylinder bores (holes) Wa1 to Wa4 of the cylinder block (workpiece) W. The main shaft motor 18 is rotationally driven via a gear box 13 a provided in the main shaft head 13 with a space in the direction parallel to the paper surface. Each tool spindle 17A, 17B is coaxially formed with an inner hole 17a (see FIG. 6) through which an operating shaft 50 described later is inserted. The jig unit 20 supported by the base 10 via the support beam 21 supports a jig table 23 so as to be movable in a horizontal direction parallel to the paper surface of FIG. 2, and from the previous processing station, the paper surface of FIG. The cylinder block W carried in by the transfer bar 25 extending in parallel is clamped on the jig table 23.
[0022]
A first quill 30A and a second quill are provided at the lower ends of the respective tool spindles 17A, 17B with rough finishing blades 36, intermediate finishing blades 41 and fine finishing blades 46 for machining the cylinder bores Wa1 to Wa4 of the cylinder block W, respectively. 30B is mounted coaxially. Since the quills 30A and 30B are the same, the first quill 30A will be described with reference to FIGS. The first quill 30A has a cylindrical shape in which an inner hole 30a penetrating coaxially is formed, and its tip is closed by a round block 30b. On the outer peripheral surface near the tip of the first quill 30A, each one first mounting surface 31a, third mounting surface 31c, and two second mounting surfaces 31b are arranged every 90 degrees in parallel with the rotational axis of the quill 30A. It is formed symmetrically. The cross-sectional shapes of the mounting surfaces 31a to 31c are all the same L-shape, and the first mounting surface 31a and the third mounting surface 31c are formed every 180 degrees, and the first mounting surface 31a and the third mounting surface 31c are formed between the mounting surfaces 31a and 31c. Two attachment surfaces 31b are formed.
[0023]
One end of a rigid square rod-shaped rough finish cutting tool holder 35 is fixed to the first mounting surface 31a on the tool spindle 17A side by a bolt 37, and a rough finish cutting tool 36 is fixed to a tip portion extending to the block 30b side. (See FIGS. 3 and 4). Similarly, one end of a square-finished medium-finishing blade holder 40 and a fine-finishing blade holder 45 are fixed to the second mounting surface 31b and the third mounting surface 31c by bolts 44 and 49, respectively. The intermediate finishing blade 41 and the fine finishing blade 46 are fixed to the front end of the block 30b. The intermediate finishing blade holder 40 and the fine finishing blade holder 45 are provided with notches from the mounting surfaces 31b and 31c between the fixing portions of the bolts 44 and 49 and the mounting portions of the cutting tools 41 and 46, respectively. Flexible portions 40a and 45a are formed that enable the tip portions provided with the cutting tools 41 and 46 to bend elastically outward in the radial direction. Accordingly, the rotational radius of the cutting edge of the rough finishing blade 36 is constant, but the rotational radius of each cutting edge of the intermediate finishing blade 41 and the fine finishing blade 46 is variable. In addition, the cutting edges of the fine finishing tool 46, the intermediate finishing tool 41, and the rough finishing tool 36 are arranged in this order so as to be on the distal end side (side toward the cylinder block W) of the first quill 30A.
[0024]
The operating shaft 50 inserted into the tool spindle 17A from the rear side (upper side) of the spindle head 13 has a tip end portion in which a guide groove 51 is formed in the axial direction and is slidably fitted in the inner hole 30a of the first quill 30A. The rotation with respect to the first quill 30A is prevented by inserting the tip of the pin 32 provided in the first quill 30A aligned in the axial direction with the rough finishing blade holder 35 into the guide groove 51. Tapered grooves 52a and 52b along the longitudinal direction are formed at the distal end portion of the operating shaft 50 at angular positions corresponding to the respective blade holders 40 and 45, and the respective first tapered grooves 52a corresponding to the respective intermediate finish blade holders 40. The depth of the second taper groove 52b corresponding to the fine finishing blade holder 45 becomes shallower as the tip of the working shaft 50 is advanced. The L-shaped slide pieces 43 and 48 slidably provided in the respective taper grooves 52a and 52b have their projections 43a and 48a slidably held in the radial direction between the tip of the first quill 30A and the block 30b. Has been.
[0025]
Also, the first quill 30A has a radial direction in the longitudinal direction, at the distal end side of the flexible portions 40a, 45a of the blade holders 40, 45, in the angular direction, at positions corresponding to the tapered grooves 52a, 52b, respectively. A first guide hole 33 and a second guide hole 34 penetrating therethrough are formed. Both ends of each of the movable pins 42 and 47 slidably inserted into the respective guide holes 33 and 34 are brought into contact with the distal end side from the respective flexible portions 40a and 45a of the slide pieces 43 and 48 and the blade holders 40 and 45, respectively. It is touched.
[0026]
In particular, in the present embodiment, as shown in FIG. 5, the first guide hole 33 aligned with the semi-finished blade holder 40 is formed as a stepped hole, and the movable pin 42 is formed in a plug shape with a large diameter head. Has been. Of FIG. right In a state where the operating shaft 50 is retracted and the blade holder 40 is retracted radially inward as in the half section, the head of the movable pin 42 is seated on the bottom surface of the large diameter portion of the first guide hole 33 and has a diameter. Further retracting inward in the direction is prevented, and a gap C is formed between the slide piece 43 that contacts the inner end portion of the movable pin 42 and the taper surface of the operating shaft 50 by rotational centrifugal force. . On the other hand, as shown in the left half section of FIG. 5, when the operating shaft 50 moves forward and the blade holder 40 protrudes radially outward, the bottom surface of the tapered groove 52a of the operating shaft 50 is the slide piece 43 and the movable pin. 42 is pushed outward in the radial direction so that the head of the movable pin 42 is separated from the seating position on the bottom surface of the large diameter portion of the first guide hole 33.
[0027]
In other words, in a state where the operating shaft 50 is retracted for precision finishing, the operating shaft 50 has a gap C between the bottom of the slide piece 43 and the bottom of the pair of tapered grooves 52a opposed in the radial direction. As a result, during the fine finishing process, the elastic force directed radially inward of the intermediate finishing blade holder 40 is prevented from acting on the operating shaft 50 via the movable pin 42 and the slide piece 43. 46 is configured to prevent position fluctuations.
[0028]
With the above configuration, when the operating shaft 50 advances toward the block 30b with respect to the first quill 30A, each slide piece 43 in each first tapered groove 52a moves outward in the radial direction. Each of the semi-finished cutting tool holders 40 is transmitted by the movable pin 42 to advance the intermediate finishing tool 41 in the radial direction so that the rotational radius of the cutting edge increases, and at the same time, each slide piece 48 in each second tapered groove 52b. Is moved inward in the radial direction, and this movement is transmitted to each precision finishing blade holder 45 by each movable pin 42 to retract the precision finishing blade 46 in the radial direction so that the turning radius of the cutting edge is reduced. On the contrary, if the operating shaft 50 is retracted with respect to the first quill 30A, the intermediate finishing blade 41 is retracted in the radial direction and the rotational radius of the cutting edge is reduced, and the fine finishing blade 46 is advanced in the radial direction and The turning radius of the cutting edge increases. By these forward and backward movements in the radial direction, the turning radius of the cutting edge of the semi-finished cutting tool 41 changes between a predetermined turning radius and a smaller turning radius, and the turning radius of the cutting edge of the fine finishing tool 46 is It varies between a predetermined precision finishing turning radius larger than the intermediate finishing turning radius and a turning radius smaller than the intermediate finishing turning radius. The radius of rotation of the cutting edge of the rough finish cutting tool 36 is smaller than the radius of rotation for intermediate finishing.
[0029]
As shown in FIG. 6, the operating device 60 that moves the operating shaft 50 in the axial direction with respect to the tool spindle 17 </ b> A has a housing 61 attached to the rear end portion of the spindle head 13 via a support member 68. . A cylindrical body 62 is slidably guided and supported on the housing 61 so as to be parallel to the rotational axis of the tool spindle 17A, and a bracket 63 that is rotatably connected to the rear portion of the operating shaft 50 via a bearing is a cylinder. It is fixed to the lower end of the shaped body 62. The lower half portion of the feed screw 65 supported only rotatably on the housing 61 via a bearing so as to be coaxial with the cylindrical body 62 is screwed into a nut 64 fixed to the cylindrical body 62, and the feed An upper end portion of the screw 65 is connected to a servo motor 66 attached to the housing 61 via a joint 67. When the servo motor 66 is operated, the feed screw 65 rotates to move the cylindrical body 62 in the axial direction, and the operating shaft 50 is moved in the axial direction with respect to the tool spindle 17A via the bracket 63.
[0030]
Next, the operation of the above-described boring apparatus for a plurality of holes will be described with reference to a process diagram shown in FIG. At the start of step a in FIG. 7, the jig table 23 is indexed to a position where the first and third bores Wa1, Wa3 of the cylinder block W to be placed are coaxial with the quills 30A, 30B. Each tool spindle 17A, 17B is rotationally driven by a spindle motor 18. In step a, in the state where the processed cylinder block W is first unloaded and the unprocessed cylinder block W is loaded and clamped to the jig table 23, the operating shaft 50 is advanced by the operating device 60, and the fine finishing blade 46 is moved. The cutting edge is moved backward so that the turning radius of the cutting edge is smaller than the turning radius of the intermediate finishing, and the cutting edge 41 is advanced to set the turning radius of the cutting edge to a predetermined turning radius of the finishing work (see step a). In this state, the spindle head 13 is lowered by the servo motor 14 to advance the tool spindles 17A and 17B toward the cylinder block W, and the quills 30A and 30B are first fast-forwarded to approach the cylinder block W, followed by predetermined processing. Each intermediate finishing tool 41 is advanced at a speed to a position where it passes through the first and third bores Wa1, Wa3 (see step b). As a result, the first and third bores Wa1 and Wa3 are first subjected to rough finishing by the rough finishing blade 36, and subsequently subjected to intermediate finishing by the respective intermediate finishing blades 41. Next, the operating shaft 50 is slightly retracted by the operating device 60, the intermediate finishing blade 41 is slightly retracted to slightly decrease the rotational radius of the blade edge (see step c), and any of the blade edges of the blade tools 36, 41, 46 is selected. The spindle head 13 is quickly returned to a predetermined position by the servo motor 14 in a state where it does not come into contact with the inner surfaces of the first and third bores Wa1 and Wa3 that have been subjected to intermediate finishing, and the quills 30A and 30B are returned to the predetermined positions. Extracted from the first and third bores Wa1, Wa3.
[0031]
Next, the jig table 23 is moved in the horizontal direction so that the cylinder block W is indexed to a position where the second and fourth bores Wa2 and Wa4 are coaxial with the quills 30A and 30B, and the working shaft 50 is slightly advanced to finish the cylinder. The cutting tool 41 is advanced to the same position as in step a, and the rotation radius of the cutting edge is set to a predetermined intermediate finishing rotation radius (see step d). In this state, the servo motor 14 is operated to advance the tool spindles 17A and 17B toward the cylinder block W in the same manner as described above, and the quills 30A and 30B are first brought close to the cylinder block W by rapid feed, Each semi-finished cutting tool 41 is advanced to a position where it passes through the second and fourth bores Wa2 and Wa4 at a machining speed, and the second and fourth bores Wa2 and Wa4 are rough-finished by the rough-finishing tool 36, and each of the semi-finished cutting tools. A semi-finishing process is performed by 41 (see step e).
[0032]
Next, the operating shaft 50 is retracted by the operating device 60, the intermediate finishing blade 41 is retracted to make the rotational radius of the blade edge smaller than the rotational radius of the intermediate finishing machining, and the precision finishing blade 46 is advanced to increase the rotational radius of the blade edge. A predetermined precision finishing rotation radius is set (see step f). Then, the tool spindles 17A, 17B are retracted by the servo motor 14, and the fine finishing blades 46 of the quills 30A, 30B are used to finely finish the second and fourth bores Wa2, Wa4 (see step g). Is quickly returned to a predetermined position, and the quills 30A and 30B are extracted from the first and third bores Wa1 and Wa3.
[0033]
Next, the jig table 23 is moved in the horizontal direction so that the cylinder block W is indexed to a position where the first and third bores Wa1, Wa3 are coaxial with the quills 30A, 30B, and then the operating shaft 50 is moved forward a little. Then, the fine finishing blade 46 is retracted by a small amount to reduce the rotational radius of the blade edge by a small amount (see step h), and all of the cutting edges of each of the blade tools 36, 41, 46 are subjected to intermediate finishing. The tool spindles 17A and 17B are fast-forwarded and lowered by the servo motor 14 in a state where they are not in contact with the inner surfaces of the three bores Wa1 and Wa3, until the fine finishing blades 46 pass through the first and third bores Wa1 and Wa3. Each quill 30A, 30B is inserted.
[0034]
Next, the operating shaft 50 is slightly retracted, and the fine finishing blade 46 is advanced to the same position as in step f, and the rotation radius of the cutting edge is set to a predetermined fine finishing rotation radius (see step i). In this state, similarly to the step g, the tool spindles 17A and 17B are moved backward by the servo motor 14 and the first and third bores Wa1 and Wa3 are finely finished by the fine finishing blades 46 of the quills 30A and 30B (step j). Next, the spindle head 13 is rapidly returned to a predetermined position, and the quills 30A and 30B are extracted from the first and third bores Wa1 and Wa3. Thereby, one cycle of processing of the four cylinder bores Wa1 to Wa4 of the cylinder block W is completed, and the process returns to the first step a.
[0035]
According to the above-described embodiment, since the fine finishing of each of the cylinder bores Wa1 to Wa4 is performed after all the cylinder bores Wa1 to Wa4 are finished, the fine finishing is performed even when the rigidity of the cylinder block W is low. The cylinder bores Wa1 to Wa4 that have already been processed are not affected by the residual distortion caused by rough finishing or intermediate finishing with a large depth of cut, so that the precisely finished cylinder bores Wa1 to Wa4 have a predetermined accuracy. Can be maintained.
[0036]
Even in the above-described conventional boring device for a plurality of holes, it is possible to perform the fine finishing of each of the cylinder bores Wa1 to Wa4 after all the cylinder bores Wa1 to Wa4 are finished in the same manner as in this embodiment. Is possible. However, in the boring apparatus for a plurality of holes in the prior art, the semi-finished cutting tool is fixed to the quill, so that the tool spindles 17A and 17B between the process c and the process d are quickly returned and the process between the process h and the process i is performed. During rapid feed insertion of the tool spindles 17A and 17B, there arises a problem that the cutting edge of the semi-finished cutting tool comes into contact with the inner surfaces of the first and third bores Wa1 and Wa3 that have been subjected to the semi-finishing process to reduce the life of the semi-finishing cutting tool . However, according to this embodiment, the tool spindles 17A and 17B between the process c and the process d are quickly returned and the tool spindles 17A and 17B are inserted between the process h and the process i at a rapid feed time. None of the cutting edges of 36, 41, and 46 come into contact with the inner surfaces of the first and third bores Wa1, Wa3, so that the cutting edges are connected to the inner surfaces of the cylinder bores Wa1, Wa3 at the time of quick return and fast feed insertion. The life of each blade 36, 41, 46 is not reduced by contact.
[0037]
The cylinder bores Wa2 and Wa4 that have been subjected to intermediate finishing for the second time are subjected to precision finishing by retreating the tool spindles 17A and 17B that is performed immediately after the intermediate finishing, so that the stroke that is not processed is intermediate to the first time. Since only the finished cylinder bores Wa1 and Wa3 are provided, an increase in machining time can be reduced, and a decrease in productivity can be reduced. Furthermore, in this embodiment, strokes that are not processed between step c and step d and between step h and step i are fast rewind and fast feed, respectively, where the stroke speed is high, so that the productivity is further reduced. Become.
[0038]
Further, in this embodiment, the semi-finishing turning radius can be adjusted by changing the position of the working shaft 50 in the axial direction during the steps a and d by the servo motor 66 of the actuating device 60. It is also easy to adjust the machining allowance with the finishing blade 46.
[0039]
In this embodiment, the rough finish cutting tool 36 is provided in the quills 30A and 30B so that rough finishing is also performed in the intermediate finishing process. In this way, a rough finishing process that is performed in advance is unnecessary. Productivity can be improved by reducing the processing time as a whole. However, the present invention can also be implemented by rough-finishing each of the bores Wa1 to Wa4 in advance and not providing a rough finish cutting tool on the quills 30A and 30B.
[0040]
In the above embodiment, the pitch of the tool spindles 17A and 17B is twice the pitch of the cylinder bores Wa1 to Wa4, the number of the tool spindles 17A and 17B is two, and the present invention is a cylinder block of an in-line four-cylinder internal combustion engine. In this way, the stroke that does not perform machining for all six strokes is only one return stroke and insertion stroke for each stroke, and the stroke time that does not perform machining for the entire machining time. Therefore, the productivity can be minimized. The same effect is obtained when machining the cylinder bore of the cylinder block of the in-line 6-cylinder internal combustion engine, the pitch of the tool spindles 17A and 17B is twice the pitch of the cylinder bore Wa, and the number of tool spindles 17A and 17B is three. The pitch of the tool spindles 17A and 17B is twice the pitch of the cylinder bore Wa, and the present invention can be applied with the number of tool spindles 17A and 17B being half the number of cylinder bores Wa. .
[0041]
In the above embodiment, the quills 30A and 30B are moved forward and backward in the axial direction to provide the single working shaft 50 for moving the blades 41 and 46 in the radial direction, and the intermediate finishing blade 41 and the fine finishing blade 46 are provided. Is configured to advance and retract in the radial direction opposite to each other in accordance with the advancement and retraction of the operating shaft 50, so that each cutting tool is moved back and forth immediately after each intermediate finishing step, each fine finishing step, and the intermediate finishing step except the last. Adjustment of the radius of rotation of the cutting edge of each cutting tool necessary for insertion of each cutting tool prior to the fine finishing process for each hole that has been semi-finished in the intermediate finishing process can be performed by advancing and retreating one operating shaft 50. This makes it possible to simplify the structure of the boring apparatus for plural holes.
[0042]
In the case of a cylinder bore of a cylinder block of an in-line 6-cylinder internal combustion engine, the pitch of the tool spindles 17A and 17B is three times the pitch of the cylinder bore Wa, and the number of tool spindles 17A and 17B is two. You can also. In this case, after repeating step b to step d twice, step e to step g are performed, and further step h to step j are repeated twice. The return stroke and the insertion stroke are 4 times. Similarly, in the case of a cylinder bore of a cylinder block of an inline 8-cylinder internal combustion engine, the pitch of the tool spindles 17A and 17B is four times the pitch of the cylinder bore Wa, and the number of tool spindles 17A and 17B is two, and the present invention is applied. In this case, step e to step g are performed after step b to step d are repeated three times, and step h to step j are further repeated three times, and processing is performed for 14 strokes. The non-existing strokes are 6 return strokes and 6 insertion strokes.
[0043]
That is, generally, immediately after the semi-finishing process except the last, the turning radius of each cutting edge of each cutting tool 41, 46 is made smaller than the semi-finishing turning radius, and the quills 30A, 30B are retracted, and the final finishing process is completed. Immediately after the end, the first fine finishing process is performed by retracting the quills 30A and 30B with the cutting edge of the precision finishing blade 46 as the precision finishing machining radius, and each cylinder bore Wa subjected to the intermediate finishing process in the intermediate finishing process excluding the last is processed for each cylinder bore Wa. The rotational radius of each cutting edge of the cutting tools 41 and 46 is made smaller than the turning radius of the intermediate finishing machining, and the quills 30A and 30B are advanced and inserted into the cylinder bores Wa, and then the rotational radius of the cutting edge of the precision finishing cutting tool 46 is set back as the fine finishing processing rotation radius. This is done by a fine finishing process.
[0044]
In the above-described embodiment, the case where the present invention is applied to the machining of the cylinder bore Wa of the cylinder block W has been described. However, the present invention is not limited to this, and a plurality of the workpieces W arranged in parallel at the same pitch. This can be applied to the case of machining the hole Wa.
[0045]
Moreover, although each embodiment mentioned above demonstrated the case where a quill was attached to each of a plurality of tool spindles and the same number of holes as the tool spindle were machined simultaneously, the present invention is not limited to this, and one tool spindle is used. It can also be applied to processing holes one by one with a quill attached. In this case as well, it is possible to maintain precisely finished holes with a predetermined accuracy even when the rigidity of the workpiece is low. It is possible to reduce the increase in machining time because the cutting edge does not reduce the life of each cutting tool because the cutting edge does not contact the inner surface of the hole during the axial retreat and insertion without machining. Thus, it is possible to obtain each effect that the decrease in productivity can be reduced.
[0046]
Note that the axial movement of the blade and the quill to which the blade is attached is relative to the workpiece. In addition to moving the tool spindle and moving the blade and quill relative to the workpiece as in the above-described embodiment, the workpiece W Needless to say, the technical idea of the present invention includes moving the cutting tool and the quill relative to the workpiece by moving the jig table 23 that supports the workpiece.
[0047]
【The invention's effect】
Claim 1 and claim 6 According to the multi-hole machining method, each hole is finely finished after all the holes have been semifinished. Therefore, even if the rigidity of the workpiece is low, the precisely finished hole can be maintained at a predetermined accuracy. In addition, the retraction in the axial direction of each cutting tool performed immediately after the semi-finishing process except the last, and the insertion of each cutting tool prior to the fine finishing process for each hole semi-finished in this semi-finishing process, the turning radius of the cutting edge of each cutting tool Therefore, the cutting edge does not come into contact with the inner surface of the hole during the retreating and insertion in the axial direction, thereby reducing the life of each cutting tool. In addition, for the holes that have been semi-finished at the end, precise finishing is performed by retreating the axial direction of each cutting tool immediately after the semi-finishing, and this reduces the stroke that is not processed, thus increasing the machining time. It is possible to reduce the decrease in productivity by reducing the amount.
[0048]
According to the method for machining a plurality of holes according to claim 2, even when the cylinder block of the internal combustion engine has low rigidity, the precisely finished cylinder bore can be maintained at a predetermined accuracy, and the cutting edge of each cutting tool is formed on the inner surface of the hole. The life of each cutting tool is not reduced by contact with the blade, and the increase in processing time can be reduced to reduce the decrease in productivity.
[0049]
According to the method for machining a plurality of holes according to claim 3, since the stroke speed when machining is not performed is increased, the increase in machining time can be further reduced to further reduce the productivity.
[0050]
According to the method for machining a plurality of holes according to claim 4, since rough finishing is performed in the intermediate finishing process, a rough finishing process that is performed in advance is not required, so that the processing time is reduced as a whole and productivity is improved. be able to.
[0051]
According to the method for machining a plurality of holes according to claim 5, the strokes that are not machined are only one return stroke and the insertion stroke, and the ratio of the stroke time that is not machined to the whole machining time is the smallest. The decrease in sex can be minimized.
[Brief description of the drawings]
FIG. 1 Multiple holes according to the present invention Processing method One embodiment Boring machine for multiple holes It is a side view which shows the whole structure.
FIG. 2 is a front view showing a lower half portion of the boring apparatus for a plurality of holes shown in FIG. 1;
3 is an enlarged cross-sectional view taken along line 3-3 in FIG.
4 is a cross-sectional view taken along line 4-4 of FIG.
5 is a cross-sectional view taken along line 5-5 of FIG.
6 is an actuating device for an actuating shaft for advancing and retracting each cutting tool of the boring device for a plurality of holes shown in FIG. 1 in the radial direction;
FIG. 7 is a process diagram showing a method for processing a plurality of holes according to the present invention.
FIG. 8 is a process diagram showing a processing method for a plurality of holes according to the prior art.
[Explanation of symbols]
17A, 17B ... Tool spindle, 20 ... Jig unit, 30A, 30B ... Quill, 36 ... Rough finish cutting tool, 41 ... Medium finishing tool, 46 ... Fine finishing tool, 50 ... Working shaft, W ... Workpiece (cylinder block), Wa1-Wa4 ... holes (cylinder bores).

Claims (6)

A method of machining a plurality of holes arranged in parallel with each other at the same pitch on a single workpiece, the number of holes being an integral number of the number of holes, and parallel to each other at a pitch that is an integral multiple of the pitch of the holes. In a machining method for a plurality of holes, in which a semi-finished cutting tool and a precision finishing tool that rotate together around a rotational axis lined up are moved in the direction of the rotational axis, and the blade tool is sequentially inserted into the unprocessed hole and processed.
In the semi-finishing of each hole, the cutting edge of the semi-finishing tool is set to a predetermined semi-finishing turning radius, and the turning radius of the cutting edge of the fine finishing tool is set smaller than the turning radius of the finishing touch. In the semi-finished cutting tool, it is performed by a plurality of semi-finishing processes that sequentially advance and insert into the unprocessed holes,
Immediately after the intermediate finishing step except for the last, each cutting tool retracts in the axial direction with the rotational radius of each cutting edge being smaller than the intermediate finishing rotational radius,
In the fine finishing of each hole, immediately after the end of the last semi-finishing step, each cutting tool is set in the axial direction by setting the turning radius of the cutting edge of the fine finishing tool to a predetermined precision finishing turning radius larger than the intermediate finishing turning radius. In the first fine finishing step for retreating to the first, the hole that was finally finished in the middle finishing process is performed first, and for each hole that was finished in the middle finishing process except the last, the turning radius of each cutting edge of each cutting tool is set to the middle A plurality of holes are formed by performing a fine finishing step in which the rotational radius of the cutting edge of the fine finishing tool is retreated in the axial direction as the fine finishing rotational radius after being advanced and inserted into each hole as being smaller than the finishing rotational radius. Processing method.   The multi-hole machining method according to claim 1, wherein the workpiece is a cylinder block of an internal combustion engine, and the plurality of holes are four or more even-numbered cylinder bores arranged in alignment. Method.   3. The multi-hole machining method according to claim 1, wherein the cutting of each cutting tool performed immediately after the intermediate finishing step except the last is performed by rapid return, and the intermediate finishing is performed in the intermediate finishing step except the last. A method for processing a plurality of holes, wherein the insertion of each cutting tool prior to the fine finishing step for each hole is performed by rapid feed.   4. The multi-hole machining method according to claim 1, wherein the rotation radius of the cutting edge is smaller than the rotation radius of the intermediate finish machining by rotating together with the blades around the rotation axis. 5. A method for machining a plurality of holes, wherein rough finishing of the hole is also performed in the intermediate finishing step by using a rough finishing blade positioned forward of the intermediate finishing tool in the forward direction.   5. The multi-hole machining method according to claim 1, wherein a pitch of the rotation axis is twice a pitch of the plurality of holes, and the number of the rotation axes is the plurality. A method for machining a plurality of holes, characterized in that the number of holes is half of the number of holes. A method of machining a plurality of holes aligned in parallel with each other in a workpiece, wherein a semi-finishing blade and a fine-finishing blade that rotate together around one rotation axis are moved in the direction of the rotation axis, In the cutting method of a plurality of holes that are sequentially inserted into the holes that are not processed by the cutting tool and processed,
In the semi-finishing of each hole, the cutting edge of the semi-finishing tool is set to a predetermined semi-finishing turning radius, and the turning radius of the cutting edge of the fine finishing tool is set smaller than the turning radius of the finishing touch. In the semi-finished cutting tool, it is performed by a plurality of semi-finishing processes that sequentially advance and insert into the unprocessed holes,
Immediately after the intermediate finishing step except for the last, each cutting tool retracts in the axial direction with the rotational radius of each cutting edge being smaller than the intermediate finishing rotational radius,
In the fine finishing of each hole, immediately after the end of the last semi-finishing step, each cutting tool is set in the axial direction by setting the turning radius of the cutting edge of the fine finishing tool to a predetermined precision finishing turning radius larger than the intermediate finishing turning radius. In the first fine finishing step for retreating to the first, the hole that was finally finished in the middle finishing process is performed first, and for each hole that was finished in the middle finishing process except the last, the turning radius of each cutting edge of each cutting tool is set to the middle A plurality of holes are formed by performing a fine finishing step in which the rotational radius of the cutting edge of the fine finishing tool is retreated in the axial direction as the fine finishing rotational radius after being advanced and inserted into each hole as being smaller than the finishing rotational radius. Processing method.

Images