JP2004243514A - Machining jig of cylinder block and machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To finish process a cylinder bore and a crank hole at high precision without increasing costs. <P>SOLUTION: A cylinder bore 1 and a crank hole of a cylinder block 5 are processed under a condition that a dummy head 11 instead of the cylinder head is mounted on a cylinder head mounting face 5a of the cylinder block 5. A bead part 23 projecting toward the cylinder head 5 is attached to the dummy head 11 at a portion opposed to a peripheral edge of the cylinder bore 1, and a recessed part 25 is installed outside the bead part 23. When the dummy head 11 is mounted on the cylinder block 5 using a bolt, a force acting between the bead part 23 and the cylinder block 5 controls deformation of the cylinder block 5 by pressing and elastically deforming a dummy head body 13 to the bead part 23 by an actuation of the recessed part 25. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a cylinder block machining jig for machining a bore inside the cylinder block or a crank hole for rotatably supporting a crankshaft in a state where a dummy head instead of the cylinder head is attached to the cylinder head attachment surface of the cylinder block. Related to processing method.

  Since the cylinder bore of the cylinder block and the crank hole that supports the rotation of the crankshaft are important parts that determine the engine performance, the roundness and cylindricity, which are the shape accuracy, are finished with high accuracy (honing and line boring). Is required.

  However, as shown in FIG. 22, even if the cylinder bore 1 and the crank hole 2 are finished as a single item, no matter how high the precision, the engine is provided with the gasket 7 sandwiched between the cylinder head 3 and the cylinder block 5 and the bolt 23, the cylinder bore 1 is deformed by bolts 9 arranged around the cylinder bore 1 so as to be pulled in four directions as shown by an arrow A in FIG. The coaxiality deteriorates and deforms.

  The deformation of the cylinder bore causes a gap between the cylinder ring and the piston ring, resulting in deterioration of oil consumption. Therefore, as a means for preventing the gap, it is conceivable to increase the tension of the piston ring.

  However, in this countermeasure, the sliding performance of the piston ring is increased, so that the engine performance is deteriorated.

  In addition, since the crank hole has a bearing function of rotatably supporting the crankshaft, the above-described deformation causes a sliding resistance of the crankshaft, and deteriorates engine performance.

  In order to improve these, it is required that a deformation corresponding to a state where the cylinder head and the gasket are assembled to the cylinder block be given to the cylinder bore and the crank hole, and the cylinder bore and the crank hole be finished in that state.

  In the method shown in FIG. 22, instead of the cylinder head 3 in the state shown in FIG. 22, a so-called dummy head (a material and a shape equivalent to the cylinder head, corresponding to the cylinder head 3 and corresponding to the bore so that cylinder bore processing can be performed). Jig with a through-hole) is used. A gasket 7 is interposed between the dummy head and the cylinder block 5, and the cylinder bore 1 and the crank hole 2 are finished with the cylinder bore 1 and the crank hole 2 deformed by fastening with a bolt 9.

  However, according to this method, the gasket 7 is crushed and deteriorated with an increase in the number of times of use, so that a large number of gaskets 7 are required in order to stably deform the cylinder bore 1 and the crank hole 2 in mass production. High costs are incurred.

For this reason, conventionally, for example, Patent Document 1 discloses an example in which a metal shim is used instead of a gasket used in an actual engine.
Japanese Patent Application Laid-Open No. 2000-52228 (paragraphs [0032] and [0034], FIG. 1) This is because the portion of the above-mentioned shim facing the cylinder block mounting surface is tapered to partially change the thickness of the shim. Thereby, the fastening force of the bolt is mainly given to the dummy head.

  However, it is extremely difficult to produce the tapered shape with stable accuracy in the above-described Patent Document 1, which leads to an increase in cost, and improvement is desired.

  Accordingly, it is an object of the present invention to enable a cylinder bore or a crank hole to be finished with high accuracy without increasing the cost.

  In order to achieve the above object, the present invention provides a method for machining a cylinder bore inside a cylinder block or a crank hole for rotatably supporting a crankshaft in a state where a dummy head instead of a cylinder head is mounted on a cylinder head mounting surface of a cylinder block. In the jig for processing a cylinder block to be provided, a bead portion projecting toward the cylinder block is provided on a portion of the dummy head facing the cylinder bore peripheral edge of the cylinder block, and the bead portion is provided on the side opposite to the cylinder bore. A concave portion is provided in the dummy head at a portion facing the cylinder head mounting surface.

  According to the present invention, when the dummy head is mounted on the cylinder block, the bead portion is pressed by the cylinder block, and the dummy head is elastically deformed by the action of the concave portion to absorb the mounting force. Even if there is a manufacturing error in the amount of protrusion, deformation of the required cylinder bore or crank hole can be easily obtained, and finishing of the cylinder bore or crank hole can be performed at low cost and with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a dummy head 11 according to a first embodiment of the present invention, FIG. 2 is a bottom view of the dummy head 11 of FIG. 1 as viewed from below, and FIG. It is A sectional drawing. However, FIG. 3 shows a state where the dummy head 11 is mounted on the cylinder block 5.

  The above-mentioned dummy head 11 is mounted on the cylinder head mounting surface 5a of the cylinder block 5 by bolts 9 instead of the cylinder head 3 and the gasket 7 shown in FIG. Or by performing honing after boring.

  In the dummy head 11, a through hole 15 corresponding to the cylinder bore 1 of the cylinder block 5 is provided in a dummy head body 13 formed of a rectangular flat plate, and four places around the through hole 15 are shown in FIG. A bolt insertion hole 17 for inserting the bolt 9 is provided. The through hole 15 has an inner diameter larger than the inner diameter of the cylinder bore 1 after finishing, and a honing working head (not shown) is inserted at the time of finishing.

  As shown in FIG. 1, a boss 19 protruding from the dummy head body 13 is provided on the opposite side of the above-mentioned bolt insertion hole 17 from the cylinder block 5, and the dummy head body 13 on the base end side of the boss 19 is provided. A flange portion 21 is provided on the side. Thereby, the base end side of the boss portion 19 that contacts the dummy head main body 13 is made larger than the top end side which is the upper part in FIG.

  As shown in FIG. 3, the dummy head 11 is provided with a through-hole 15 formed in the dummy head main body 13 on the periphery of the cylinder block 5 side, that is, on a portion of the dummy head 11 that faces the cylinder bore periphery (in FIG. An annular bead portion 23 protruding downward is provided. As shown in FIG. 2, the bead portions 3 here are integrally formed with the corresponding through holes 15 adjacent to each other.

  The above-described bead portion 23 has a bead portion through-hole 23 a having an inner diameter substantially equal to that of the through-hole 15 of the dummy head main body 13, and is inserted into an annular cutout recess 13 a formed in the dummy head main body 13. The depth of the notch 13a is shallower than the thickness of the bead portion 23, and the difference, that is, the protruding portion of the bead portion 23 from the dummy head body 13 is formed as a step B.

  Further, a gap C is formed between the outer peripheral surface 23b of the bead portion 23 and the outer peripheral side surface 13b of the cutout recess 13a. Due to the formation of the gap C, the dummy head 11 has a configuration in which the concave portion 25 is provided in a portion facing the cylinder head mounting surface 5a on the side opposite to the cylinder bore 1 with respect to the bead portion 23.

  In FIG. 3, reference numeral 5b denotes a water jacket.

  When the above-described dummy head 11 is set on the cylinder head mounting surface 5a of the cylinder block 5 and the bolt 9 is fastened, the bead portion 23 is pressed against the cylinder block 5 by a force F as shown in FIG. At this time, due to the action of the concave portion 25, the dummy head main body 13 is elastically deformed upward in FIG.

  Accordingly, when the bead portion 23 is provided, even if there is a manufacturing error in the amount of protrusion (step B), the desired deformation of the cylinder bore 1, that is, the actual cylinder head and the gasket are mounted on the cylinder block. The deformation of the cylinder bore can be easily obtained. In this case, there may be a manufacturing error in the manufacture of the bead portion 23 as described above, and therefore, it is not necessary to process the bead portion 23 with high precision. Therefore, the finish processing of the cylinder bore 1 is performed at low cost and with high precision. be able to.

  FIG. 5 shows a difference in the amount of deformation of the cylinder bore between the state where the dummy head 11 is mounted and the state where the actual cylinder head is mounted via the gasket, with respect to the size of the step B of the bead portion 23 shown in FIG. The relationship of S is shown by a solid line. The broken line corresponds to a comparative example in which the concave portion 25 is not provided (see FIG. 6).

  Although the difference S increases as the step B of the bead portion 23 increases, the difference S is intended to be reduced. Here, the upper and lower width H around S = 0 is set as the allowable range.

  In the above-described embodiment of the present invention, as shown in FIG. 4, the dummy head main body 13 is elastically deformed by the action of the concave portion 25 while being pressed by the bead portion 23, thereby suppressing the deformation of the cylinder bore 1. The region R that undergoes elastic deformation is a region insensitive to the size of the step B. That is, in the region R, regardless of the size of the step B, in other words, even if there is a manufacturing error in the size of the step B, the difference S in the deformation amount of the cylinder bore 1 can be kept within the allowable width H.

  On the other hand, if the difference S in the amount of deformation of the cylinder bore 1 in the comparative example in which the concave portion 25 is not provided is to be kept within the allowable width H, the region insensitive to the step difference of the bead portion becomes an extremely narrow region L. Requires a step to be manufactured with high precision, which leads to an increase in cost.

  That is, as shown in FIG. 6, in the comparative example in which the concave portion 25 is not provided, the dummy head main body 13 hardly deforms even when the force F is applied to the bead portion 23 when applied. The applied force acts directly on the cylinder block.

  FIG. 7 shows a deformed state of the cylinder bore 1 and the dummy head 11 according to the embodiment of the present invention, and FIG. 8 shows a deformed state of a comparative example in which the concave portion 25 is not provided. In each case, the broken line is before deformation and the solid line is after deformation. According to this, in the comparative example of FIG. 8 in which the dummy head 11 hardly deforms, the deformation of the cylinder bore 1 is larger than that of the embodiment of the present invention shown in FIG. Has become.

  As shown in FIG. 9, the bead portion 23 is crushed and deformed as indicated by a broken line in FIG. 9 by the force F when the dummy head 11 is attached to the cylinder block 5. Since it is separate from the head main body 13, sliding movement with respect to the dummy head main body 13 is possible, and this movement is possible by providing the recess 25.

  In addition, by forming the bead portion 23 separately from the dummy head main body 13, it is possible to replace the bead portion when it is worn, compared to a case where the bead portion is integrated with the dummy head main body and the entire dummy head is replaced. This is advantageous in cost. Further, when taking measures against abrasion, the measures for abrasion are limited in the case of being integrated as compared with the case where they are separately provided.

  In addition, as described above, the bead portion 23 is provided separately from the dummy head main body 13, but may be integrated as shown in FIG. Even when integrally formed, the dummy head 11 is deformed as shown by a two-dot chain line when the bead portion 23 receives the force F at the time of mounting, and the deformation of the cylinder bore 1 is suppressed.

  Further, by providing the boss portion 19 for inserting a bolt when attaching the dummy head 11 to the cylinder block 5 to the dummy head 11, the thickness of the dummy head body 13 can be reduced, and the weight of the dummy head 11 can be reduced. Can be achieved. Further, by providing the boss portion 19, it is possible to use bolts used in assembling the actual machine. In addition, by reducing the thickness of the dummy head main body 13, machining of a honing machining head or the like when machining the cylinder bore 1 is performed. The length of the tool can be shortened, and the running cost for mass production is reduced.

  The rigidity of the dummy head body 13 decreases as the thickness of the dummy head body 13 decreases, but the dummy head body 13 is deformed even if the fastening force of the bolt is small, so that the dummy head body 13 is sufficiently adhered to the cylinder block 5. Depending on the use conditions, the bolt can be used within the elastic range, and the number of times the bolt is repeatedly used can be increased. Further, since the bolt requires only a small fastening force, the contact pressure of the seat surface can be reduced, and the boss portion 19 can suppress the wear of the portion in contact with the bolt seat surface, thereby achieving a longer life.

  FIG. 11 is a diagram illustrating the effect of providing the flange portion 21 on the base end side of the boss portion 19. FIG. 7A shows an example in which the flange portion 21 is provided, and FIG. 7B shows an example in which the flange portion 21 is not provided.

  By providing the flange portion 21 as in the embodiment of the present invention, the contact area of the boss portion 19 with the dummy head main body 13 is increased as compared with the example in which the flange portion 21 is not provided. Therefore, assuming that the force acting on the upper surface of the boss portion 19 at the time of bolt fastening is equivalent to F1, the force F2 acting on the dummy head body 13 according to the embodiment of the present invention is the same force F3 acting without the flange portion 21. , It is distributed.

  As a result, local deformation of the dummy head main body 13 can be prevented. By uniformly deforming the dummy head body 13, the bead portion step B for each cylinder bore becomes uniform, and ideal cylinder bore deformation can be obtained.

  Further, by making the boss portion 19 detachable from the dummy head main body 13, when the boss portion 19 is worn, only the boss portion 19 can be replaced. In comparison, cost reduction can be achieved.

  FIG. 12 shows a second embodiment of the present invention. In this embodiment, the mating surface 27 between the bead portion 23 and the dummy head main body 13 is a tapered surface that is inclined so that the inner peripheral side is closer to the cylinder head mounting surface 5a.

  With such a shape, when the dummy head 11 is attached to the cylinder block 5 and the bead portion 23 is pushed by the cylinder block 5 and the dummy head body 13 is deformed, as shown in FIG. The tapered surface described above becomes a substantially horizontal surface in the figure, and a load acts substantially perpendicularly to the cylinder head mounting surface 5a of the cylinder block 5 as shown by an arrow D. As a result, the reproducibility of the deformation of the cylinder bore 1 when the actual cylinder head and the gasket are mounted on the cylinder block 5 is improved.

  The tapered shape of the mating surface 27 is appropriately set according to the thickness of the dummy head main body 13, the width of the gap C, the size of the step B, the rigidity of the cylinder block 5, the conditions of the gasket, and the like.

  FIG. 14 shows a third embodiment of the present invention. In this embodiment, an inner peripheral side corner portion 29 of the bead portion 23 on the side in contact with the cylinder block 5 has a curved surface shape.

  This prevents buckling marks and scratches due to local surface pressure generated on the mating surface when attaching the dummy head 11 to the cylinder block 5.

  The range in which the inner peripheral side corner portion 29 has a curved surface shape is the type of the cylinder bore 1 (connected / independent), the type of the water jacket 5b (open / closed), and the finish condition of the mating surface of the cylinder head 5 (complete / Incomplete).

  The curved shape of the inner peripheral corner 29 shown in FIG. 14 may be applied to the second embodiment shown in FIG.

  Further, as described above, the bead portion 23 formed separately from the dummy head main body 13 may be formed separately for each cylinder bore 1 as in the fourth embodiment shown in FIG. Accordingly, the bead portion 23 is not affected by the deformation of the cylinder bores 1 adjacent to each other, and the gap C is formed, the bead portion 23 slides (FIG. 9), and the mating surface 27 is tapered (FIG. 12). Can be effectively obtained, and the productivity of the bead portion 23 can be improved.

  FIG. 16 is a view for explaining the effect when the bead portion 23 is provided separately for each cylinder bore 1 as in FIG. 15 described above. FIG. 14A shows a case where the components are separated, and FIG. 14B shows a case where the components are not separated. If not separately formed, the bead portion 23 affects the deformation of the adjacent cylinder bores 1. On the other hand, in the example of the present invention in which the bead portions 23 are separately formed, each of the cylinder bores 1 is individually deformed. Does not affect the deformation of

  In addition to the above-described processing of the cylinder bore 1, the crank hole 2 (see FIG. 22) for rotatably supporting the crankshaft is also processed while the dummy head 11 is mounted on the cylinder head mounting surface 5 a of the cylinder block 5.

  By mounting the dummy head 11 on the cylinder head mounting surface 5a, as in the case of the cylinder bore 1, when the bead portion 23 is provided on the dummy head 11, even if there is a manufacturing error in the amount of protrusion (step B), the dummy head 11 can be obtained. The deformation of the crank hole 2, that is, the deformation of the crank hole with the actual cylinder head and the gasket attached to the cylinder block can be easily obtained.

  In this case, the fabrication of the bead portion 23 may have a fabrication error as described above, and therefore it is not necessary to machine the bead portion 23 with high precision. Therefore, the finishing of the crank hole 2 is the same as the finishing of the cylinder bore 1. Similarly, it can be performed at low cost and with high accuracy.

  FIG. 17A shows the roundness of the crank hole, and FIG. 17B shows the coaxiality of the crank hole for each of the steps A, B, and C, respectively. Step A is a state after processing without using a dummy head, step B is a state where a cylinder head and a gasket are assembled after processing in step A, and step C is processing using a dummy head of the present invention. Later, the cylinder head and the gasket are assembled.

  According to this, when the cylinder head and the gasket are assembled after processing using the dummy head of the present invention in both roundness and coaxiality, the processing becomes almost equivalent to the step A after processing, and After processing without using the dummy head of the present invention, the process is extremely excellent as compared with the process B of assembling the cylinder head and the gasket.

  FIG. 18 shows a method of machining the crank hole 2 as a fifth embodiment of the present invention. In this processing method, the dummy head 110 is mounted on the cylinder head mounting surface 5a of the cylinder block 5. The dummy head 110 has the same structure as the dummy head 11 shown in FIG. 1 except that the boss 19 and the flange 21 are not provided. May be provided.

  The crank hole 2 is formed between a lower surface of the cylinder block 5 and a bearing cap 31 fixed to the lower surface by a bolt (not shown). The crank hole 2 is attached to, for example, a main shaft 33 of a machining center (not shown). The line boring bar 35 is inserted to perform line boring.

  The line boring bar 35 is provided with a plurality of cutting edges 37 on the outer peripheral portion in the axial direction. As shown in FIG. 19, in a state where the line boring bar 35 is inserted into the crank hole 2 and machined, the front end side is supported by the support bearing 39. Support rotation. In this case, the center of the line boring bar 35 may be rotatably supported and processed at three points.

  After the machining of the crank hole 2 (the cylinder bore 1 has also been machined at this time), the dummy head 110 is removed, and the cylinder head mounting surface 5a of the cylinder block 5 is machined based on the machined crank hole 2. Thereby, the position between the crank hole 2 and the cylinder head mounting surface 5a can be secured with high accuracy, and the cylinder volume after the cylinder head is attached can be secured with high accuracy.

  As a sixth embodiment of the present invention, the cylinder head mounting surface 5a described above may be processed first, and then a dummy head may be mounted to process the cylinder bore 1 and the crank hole 2. The dummy head 110A used at this time is shown as a bottom view in FIG. 20 corresponding to FIG. 2, and a method of machining the crank hole 2 is shown in FIG.

  The above-described dummy head 110A does not have the boss portion 19 and the flange portion 21 shown in FIG. 1 similarly to the above-described dummy head 110, and is provided at three positions shifted from the bolt insertion holes 17 on the outer peripheral portion. , A notch 41 is provided. When the dummy head 110A is mounted on the cylinder head mounting surface 5a of the cylinder block 5, a part of the cylinder head mounting surface 5a is exposed by the notch 41.

  At the time of machining the crank hole 2, as shown in FIG. 21, the upper three vertical positioning jigs 43 and the lower three clampers 45 perform vertical positioning with respect to the cylinder block 5. The front, rear, left, and right positioning jigs 47 perform front, rear, left, and right positioning with respect to the cylinder block 5.

  The vertical positioning jig 43 includes a positioning pin 43b projecting downward from the lower surface of the base plate 43a, and the positioning pin 43b contacts a part of the cylinder head mounting surface 5a exposed through the notch 41 of the dummy head 110A. The positioning is performed with respect to the cylinder block 5 in the up-down direction. On the other hand, the lower clampers 47 are provided at three positions corresponding to the positioning pins 43b of the vertical positioning jig 43, and support the respective support pins 45a by abutting the lower surface of the cylinder block 5.

  The positioning jigs 47 at the lower part are located at both ends in the longitudinal direction of the cylinder block 5 and at two positions on one side edge (right side in FIG. 2). To position the cylinder block 5 in the front-rear (left-right direction in FIG. 2) and right-left (left-right direction in FIG. 3).

  Thus, the crank hole 2 is machined with the cylinder head mounting surface 5a as a reference in a state where the positioning pins 43b are brought into contact with the cylinder head mounting surface 5a to position the cylinder block 5 in the vertical direction. Thereby, the position between the crank hole 2 and the cylinder head mounting surface 5a can be secured with high accuracy, and the cylinder volume after the cylinder head is attached can be secured with high accuracy.

  According to the present invention, since the bead portion is formed separately from the dummy head main body, the dummy head can be slid with respect to the dummy head main body. Become. In addition, the bead part that is separate from the dummy head main body can be replaced when it is worn, which is advantageous in terms of cost compared to the case where the bead part is integrated with the dummy head main body and the entire dummy head is replaced. It becomes. Further, when taking measures against abrasion, the measures for abrasion are limited in the case of being integrated as compared with the case where they are separately provided.

  Since the mating surface between the bead portion and the dummy head main body has a tapered surface that is inclined so as to be closer to the cylinder head mounting surface toward the inner peripheral side, when the dummy head is mounted on the cylinder block, the bead portion is pressed against the cylinder block. When the dummy head body is deformed, the tapered surface becomes substantially horizontal when the axis of the cylinder bore is set to the vertical direction, and a load acts substantially perpendicularly to the cylinder head mounting surface of the cylinder block. The reproducibility of the deformation state of the cylinder bore or crank hole when the actual cylinder head and gasket are attached to the block is improved.

  Since the bead portion is provided independently for each of the plurality of cylinder bores, the bead portion is not affected by the deformation of the cylinder bores adjacent to each other, and the respective effects when the bead portion slides and the mating surface is tapered. , And the productivity of the bead portion is improved.

  Since the corner of the bead portion on the inner peripheral side on the side contacting with the cylinder block has a curved shape, buckling marks and scratches due to local surface pressure generated on the mating surface when attaching the dummy head to the cylinder block are reduced. Can be prevented.

  The dummy head is provided with a boss protruding from the dummy head main body on the side opposite to the side contacting the cylinder head mounting surface, and the boss portion is used for fastening and fixing the dummy head to the cylinder head mounting surface. Since the bolt insertion hole for inserting the bolt is provided, the thickness of the dummy head main body can be reduced, and the weight of the dummy head can be reduced. In addition, the provision of the boss enables the use of bolts used in assembling the actual machine. In addition, by reducing the thickness of the dummy head body, the length of machining tools such as a honing machining head when machining cylinder bores is reduced. And the running cost for mass production is reduced.

  Since the flange portion in which the base end side of the boss portion that contacts the dummy head main body is larger than the distal end side is provided, the contact area of the boss portion with the dummy head main body is larger than when the flange portion is not provided. Therefore, assuming that the force acting on the upper surface of the boss portion at the time of bolt fastening is equal, the force acting on the dummy head body according to the present invention is more dispersed than the force acting without the flange portion. As a result, local deformation of the dummy head main body can be prevented. By uniformly deforming the dummy head body, the amount of protrusion of the bead portion for each cylinder bore becomes uniform, and ideal cylinder bore deformation or crank hole deformation can be obtained.

  Since the boss portion is provided detachably with respect to the dummy head main body, when the boss portion is worn, only the boss portion can be replaced, and cost reduction is achieved as compared with the case where the entire dummy head is replaced. it can.

  When the dummy head is mounted on the cylinder head mounting surface of the cylinder block, a cutout for exposing a part of the cylinder head mounting surface is provided in the dummy head, and the exposed cylinder head mounting surface is formed by machining the crank hole. As a reference surface at the time, the positioning jig is brought into contact with the cylinder head mounting surface exposed through the notch, and the crank hole can be formed with reference to the cylinder head mounting surface. Even after machining, the position between the crank hole and the cylinder head mounting surface can be secured with high accuracy, and the cylinder volume after cylinder head attachment can be secured with high accuracy.

  A bead portion provided by mounting a dummy head in place of the cylinder head on the cylinder head mounting surface of the cylinder block and projecting the force acting on the cylinder block by the mounting on the dummy head at a portion of the cylinder block facing the periphery of the cylinder bore of the cylinder block. The dummy head main body is pushed by the bead portion and elastically deformed by the cylinder while the bead portion is formed by a concave portion provided at a portion of the bead portion facing the cylinder head mounting surface opposite to the cylinder bore. By controlling the force acting on the block and machining the inner surface of the cylinder bore of the cylinder block or the crank hole that rotationally supports the crankshaft, even if there is a manufacturing error in the amount of protrusion when providing the bead, the required cylinder bore Or can easily get the deformation of the crankhole Come, it is possible to perform finishing of the cylinder bore or crank hole with high accuracy at low cost.

  After processing the crank hole, the dummy head is removed from the cylinder block, and the cylinder head mounting surface of the cylinder block is processed with reference to the processed crank hole, so that the crank hole and the cylinder head mounting surface can be mutually connected. The position between them can be secured with high precision, and the cylinder volume after the cylinder head is attached can be secured with high precision.

  After processing the cylinder head mounting surface of the cylinder block, the dummy head is mounted on the cylinder head mounting surface, and the crank is mounted on the basis of the cylinder head mounting surface, which is partially exposed through a cutout provided in the dummy head. By machining the hole, the position between the crank hole and the cylinder head mounting surface can be secured with high accuracy, and the cylinder volume after the cylinder head is attached can be secured with high accuracy.

1 is a perspective view of a dummy head according to a first embodiment of the present invention. FIG. 2 is a bottom view of the dummy head of FIG. 1. FIG. 3 is an enlarged sectional view taken along line AA of FIG. 2. FIG. 4 is an operation explanatory view showing a state where the dummy head of FIG. 3 is elastically deformed. FIG. 4 is a view showing a relationship between a step of a bead portion shown in FIG. 3 and a difference in deformation amount of a cylinder bore between a state where a dummy head is mounted and a state where an actual cylinder head is mounted via a gasket. FIG. 5 is an operation explanatory view corresponding to FIG. 4 and showing a comparative example in which a concave portion outside the bead portion is not provided. FIG. 4 is a cross-sectional view illustrating deformation of a cylinder bore and a dummy head according to the first embodiment. FIG. 7 is a cross-sectional view illustrating deformation of a cylinder bore and a dummy head in the comparative example of FIG. 6. It is an operation explanatory view showing a movement in which a bead portion slides with respect to a dummy head main body. It is sectional drawing which shows the example which integrated the bead part with the dummy head main body. It is a figure explaining the effect by having provided the flange part in the base end side of the boss part in 1st Embodiment, (a) is an example which provided a flange part, (b) is an example which does not provide a flange part. It is. FIG. 6 is a sectional view showing a second embodiment of the present invention. It is an operation explanatory view of the second embodiment. It is a sectional view showing a third embodiment of the present invention. It is a bottom view showing a part of dummy head showing a 4th embodiment of this invention. It is a figure explaining the effect at the time of forming a bead part separately for every cylinder bore, (a) is a case where it is formed separately, and (b) is a case where it is not formed separately. FIG. 4A is an explanatory diagram showing the roundness of the crank hole, and FIG. 4B is a diagram showing the coaxiality of the crank hole for each of the steps A, B, and C. It is an explanatory view showing a method of processing a crank hole according to a fifth embodiment of the present invention. It is an explanatory view showing the state where crank hole processing by a 5th embodiment is performed. FIG. 16 is a bottom view of a dummy head used when machining a crank hole according to a sixth embodiment of the present invention. 9A and 9B show a crank hole machining method according to a fifth embodiment, in which FIG. 8A is a side view and FIG. 8B is a front view. FIG. 3 is an exploded perspective view when a cylinder head is attached to a cylinder block via a gasket. It is explanatory drawing which shows the deformation | transformation state of the cylinder bore by attachment of FIG.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Cylinder bore 2 Crank hole 5 Cylinder block 5a Cylinder head mounting surface 11, 110, 110A Dummy head 13 Dummy head main body 17 Bolt insertion hole 19 Boss 21 Flange 23 Bead bead 25 Recess 27 Mating surface 29 Inner peripheral angle of bead Part 41 notch

Claims (12)

  In a state in which a dummy head instead of a cylinder head is mounted on a cylinder head mounting surface of a cylinder block, a cylinder block processing jig for processing a cylinder bore inner surface of the cylinder block or a crank hole for rotatably supporting a crankshaft. A bead portion is provided on a portion of the block facing the cylinder bore peripheral edge, the bead portion protruding toward the cylinder block, and the bead portion is located on a side of the dummy head opposite to the cylinder head mounting surface opposite to the cylinder bore. A jig for processing a cylinder block, wherein a concave portion is provided in a head.   2. The cylinder block processing jig according to claim 1, wherein the bead portion of the dummy head is formed separately from a dummy head body.   The jig for processing a cylinder block according to claim 2, wherein a mating surface of the bead portion and the dummy head main body has a tapered surface that is inclined so as to be closer to the cylinder head mounting surface toward the inner peripheral side.   4. The jig for processing a cylinder block according to claim 2, wherein the bead portion is provided independently for each of a plurality of cylinder bores.   The jig for processing a cylinder block according to any one of claims 1 to 4, wherein a corner portion on an inner peripheral side of the bead portion that contacts the cylinder block has a curved surface shape.   The dummy head is provided with a boss protruding from the dummy head main body on the side opposite to the side contacting the cylinder head mounting surface, and the boss portion is used for fastening and fixing the dummy head to the cylinder head mounting surface. The cylinder block processing jig according to any one of claims 1 to 5, wherein a bolt insertion hole for inserting a bolt is provided.   The jig for processing a cylinder block according to claim 6, wherein a flange portion having a base end side of the boss portion in contact with the dummy head body larger than a front end side is provided.   8. The cylinder block processing jig according to claim 6, wherein the boss portion is provided detachably with respect to the dummy head main body.   When the dummy head is mounted on the cylinder head mounting surface of the cylinder block, a cutout for exposing a part of the cylinder head mounting surface is provided in the dummy head, and the exposed cylinder head mounting surface is formed by machining the crank hole. The jig for processing a cylinder block according to any one of claims 1 to 8, wherein the jig is used as a reference surface at the time.   A bead portion provided by mounting a dummy head in place of the cylinder head on the cylinder head mounting surface of the cylinder block and projecting the force acting on the cylinder block by the mounting on the dummy head at a portion of the cylinder block facing the periphery of the cylinder bore of the cylinder block. The dummy head main body is pushed by the bead portion and elastically deformed by the cylinder while the bead portion is formed by a concave portion provided at a portion of the bead portion facing the cylinder head mounting surface opposite to the cylinder bore. A method of machining a cylinder block, comprising controlling a force acting on the block and machining an inner surface of a cylinder bore of the cylinder block or a crank hole for rotatably supporting a crankshaft.   11. The cylinder block according to claim 10, wherein after machining the crank hole, the dummy head is removed from the cylinder block, and a cylinder head mounting surface of the cylinder block is machined based on the processed crank hole. Processing method.   After processing the cylinder head mounting surface of the cylinder block, the dummy head is mounted on the cylinder head mounting surface, and the crank is mounted on the basis of the cylinder head mounting surface, which is partially exposed through a cutout provided in the dummy head. The method for processing a cylinder block according to claim 10, wherein the hole is processed.

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