JP2011012647A - Cylinder block machining method and cylinder block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder block machining method in which the versatility of a dummy head can be improved without using a dummy head gasket, and cost can be reduced.SOLUTION: A step 9 is formed on a deck surface 2 of a cylinder block 1 constituting an internal combustion engine by protruding in a direction of assembling a cylinder head also constituting the internal combustion engine. A dummy head 11 is then assembled on the deck surface 2 with a bolt 3. A bore 5 of the cylinder block 1 is formed via the step 9 in a state that the bore is deformed. It is not necessary to use a dummy head gasket because the bore is deformed via the step 9 by assembling the dummy head 11. Also, since the dummy head 11 at a cylinder block side can be simply made flat, it is possible to easily cope with a change in specifications of the cylinder block such as a change of models and to improve the versatility of the dummy head.

Description

  The present invention relates to a method for processing a cylinder block constituting an internal combustion engine, and a cylinder block manufactured thereby.

  Generally, a bore formed in a cylinder block constituting an internal combustion engine is honed by a honing apparatus to ensure the accuracy of roundness, and then the cylinder head is bolted via a head gasket on the cylinder block. It is assembled and fixed by fastening. On the other hand, the cylinder block tends to reduce the thickness of the peripheral wall of the bore, that is, the bore portion, in order to reduce the weight.

  For this reason, even if the roundness of the bore is increased by honing, when the cylinder head is assembled and fixed on the cylinder block by bolt fastening, the stress applied to the cylinder block, particularly the bore, is caused by the load applied with the bolt fastening. Occurring and deforming the part, the roundness of the bore may be lowered.

  As a countermeasure against this, in recent years, in the finishing process of the bore part of the cylinder block, distortion (deformation) due to the load load equivalent to the case where the cylinder head is assembled to the cylinder block is given, and the bore part is honed in that state, When assembled as an internal combustion engine, the bore portion has a predetermined roundness.

  As a processing method thereof, for example, as disclosed in Patent Document 1 and schematically shown in FIG. 3, a through-hole that allows finishing processing is provided on the deck surface 102 of the cylinder block 101 with a pseudo head gasket 103 interposed therebetween. A method of assembling and processing the dummy head 104 provided with a head bolt is known.

  As another processing method, a step 106 corresponding to the head gasket is formed in the dummy head 105 instead of using the pseudo head gasket 103 as disclosed in Patent Document 2 and schematically shown in FIG. A method is also known in which the dummy head 105 is processed by being assembled to the cylinder block 101 with a head bolt.

JP 2000-52228 A JP 2008-95547 A

  However, since the processing method disclosed in Patent Document 1 uses the pseudo head gasket 103, there is a concern that the manufacturing cost may be increased. That is, the pseudo gasket 103 is crushed and deformed as the number of uses increases. For this reason, in order to give a stable deformation to the cylinder block 101, a large number of pseudo head gaskets 103 are required, and accuracy control thereof is also required. In addition, since a large number of pseudo head gaskets 103 are required, there is a problem of processing the used pseudo head gasket 103 as a waste material.

  On the other hand, since the processing method disclosed in Patent Document 2 does not use the pseudo head gasket 103, this point is superior to the processing method disclosed in Patent Document 1. However, in this processing method, since the step 106 corresponding to the head gasket needs to be formed on the dummy head 105 side, the shape of the dummy head 105 is complicated, and the number of processing steps of the dummy head 105 increases. It becomes expensive. For this reason, as a result, there is a concern that the manufacturing cost of the cylinder block is increased. Moreover, if the specification of the cylinder block 101 changes, the dummy head 105 itself is changed, such as changing the step 106 on the dummy head 105 side according to the specification, resulting in a further increase in cost.

  The present invention has been made in view of the above problems, and a cylinder block machining method capable of improving the versatility of the dummy head and reducing costs without using a pseudo head gasket, and a cylinder manufactured thereby. The purpose is to provide blocks.

  The cylinder block machining method according to claim 1, which achieves the above object, forms a step on the deck surface of the cylinder block constituting the internal combustion engine so as to protrude in the assembling direction of the cylinder head constituting the internal combustion engine. The dummy head is assembled with a bolt on the deck surface, and the bore portion of the cylinder block is processed in a state of being deformed through the step.

  According to the invention of claim 1, the step is formed on the cylinder block side, and the bore portion is deformed by a load equivalent to that when the cylinder head is assembled to the cylinder block via the step by assembling the dummy head. There is no need to use a pseudo head gasket. Further, since the dummy head can have a simple flat shape on the cylinder block side, it can easily cope with changes in the specifications of the cylinder block, such as model changes, and can improve versatility. Therefore, the cost can be reduced, and the problems relating to accuracy management and waste materials that occur when using the pseudo head gasket are not caused.

  According to a second aspect of the present invention, in the cylinder block processing method according to the first aspect, the step is defined as a height corresponding to a thickness of a head gasket provided on the deck surface when the internal combustion engine is assembled. And formed on the periphery of the bore.

  In this way, if the step of the cylinder block is formed on the periphery of the bore portion as a height corresponding to the thickness of the head gasket, the bore portion can be made equivalent to the case where it is assembled as an internal combustion engine by assembling the dummy head. Since it can be deformed, it can be processed with high accuracy so that the bore has a predetermined roundness.

  According to a third aspect of the present invention, in the cylinder block processing method according to the second aspect, after the processing of the bore portion is finished, the step is cut and the deck surface is processed flat.

  As described above, if the step is cut and the deck surface of the cylinder block is processed to be flat after completion of the processing of the bore portion, it is possible to ensure the reliability of the head gasket when assembled as an internal combustion engine. That is, in the processing methods disclosed in Patent Documents 1 and 2 described above, in order to assemble the dummy head in a state where the deck surface of the cylinder block is processed flat, a pseudo head gasket (in the case of Patent Document 1), Due to the pressure contact of the step of the dummy head (in the case of Patent Document 2), the deck surface is likely to be depressed or scratched. For this reason, when assembled as an internal combustion engine, there is a concern about reducing the reliability of the head gasket. However, in the present invention, a step having a height equivalent to the thickness of the head gasket formed on the cylinder block side for the machining of the bore portion is cut after the machining of the bore portion to finish the deck surface flatly. Therefore, the reliability of the head gasket when assembled as an internal combustion engine is ensured.

  Furthermore, the invention of the cylinder block according to claim 4 that achieves the above object is characterized by being manufactured by the processing method according to any one of claims 1 to 3.

  According to the invention of claim 4, when assembled as an internal combustion engine, an inexpensive cylinder block can be obtained in which the bore portion can have a predetermined roundness and the reliability of the internal combustion engine can be improved.

  According to the present invention, since the bore portion is processed in a state where the dummy head is assembled by forming a step on the cylinder block side without using the pseudo head gasket, the versatility of the dummy head can be improved. Cost reduction.

It is a top view which shows the deck surface at the time of the process of the cylinder block by one embodiment of this invention. It is the sectional view on the AA line of FIG. It is a figure which shows typically the outline | summary of the conventional cylinder block process. It is a figure which shows typically the outline | summary of the conventional cylinder block process.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view showing a deck surface during processing of a cylinder block according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA of FIG. In the cylinder block machining method according to the present embodiment, a dummy head 11 as a machining jig is assembled to the deck surface 2 of the cylinder block 1 to be machined by the head bolt 3, and thereby the cylinder head is assembled to the cylinder block 1. The bore portion 5 is finished by honing while the bore portion 5 is deformed by the same load load as that of the case.

  Here, the bore portion 5 has a piston slidably mounted therein, and the number of cylinders corresponding to the specification is opened in the deck surface 2 and formed in the cylinder block 1 in a cylindrical shape. FIG. 1 shows the bores 5 and 5 having two cylinders. Further, on the inner peripheral surface side of each bore portion 5, a cylindrical cylinder liner 6 is internally provided by casting, such as casting or press fitting. The bore portion 5 may be formed directly on the cylinder block 1 without providing the cylinder liner 6.

  Further, a water jacket 7 is formed in the cylinder block 1 so as to open to the deck surface 2 and around the bore portion 5, and a head bolt 3 for assembling a cylinder head constituting the internal combustion engine is screwed. A plurality of bolt holes 8 are formed at equal intervals so as to sandwich the bore portion 5.

  In the present embodiment, the height corresponding to the thickness of the head gasket that protrudes in the cylinder head assembly direction over the entire periphery of the bore portion 5 of the deck surface 2 and is interposed when the cylinder head is assembled. The step 9 is formed. That is, before finishing the bore portion 5, the deck surface 2 of the cylinder block 1 is not processed flat, but a step 9 having a height corresponding to the thickness of the head gasket is left around the bore portion 5. To process.

  On the other hand, the dummy head 11 is formed with a through hole 12 into which the honing head of the machining tool can be inserted and removed corresponding to the bore portion 5 of the cylinder block 1 and a bolt corresponding to the bolt hole 8 of the cylinder block 1. A through hole 13 is formed. Further, at least the surface of the dummy head 11 on the cylinder block 1 side is formed flat.

  In the present embodiment, when finishing the bore portion 5 of the cylinder block 1, the head bolt 3 is fastened to the bolt hole 8 of the cylinder block 1 through the bolt through hole 13 of the dummy head 11 as shown in FIG. 2. Then, the dummy head 11 is assembled to the cylinder block 1. As a result, the bore portion 5 of the cylinder block 1 is deformed by applying a load equivalent to the case where the cylinder head is assembled through the peripheral step 9. In this state, the inner peripheral surface of the cylinder liner 6 of the bore portion 5 is finished by honing through the through hole 12 of the dummy head 11.

  Thereafter, when finishing the bore portion 5 is finished, the dummy head 11 is removed, the step 9 of the cylinder block 1 is cut, and the head surface 2 is processed flat.

  As described above, in this embodiment, the step 9 is formed so as to protrude from the head surface 2 of the cylinder block 1, and is equivalent to the case where the cylinder head is assembled to the bore portion 5 via the step 9 by assembling the dummy head 11. Therefore, it is not necessary to use a pseudo head gasket as disclosed in Patent Document 1. Further, since the dummy head 11 has a simple flat shape on the cylinder block 1 side, it can easily cope with a change in the specification of the cylinder block 1 such as a model change, and can improve versatility. Therefore, the manufacturing cost of the cylinder block 1 can be reduced, and the problems relating to accuracy management and waste materials that occur when using the pseudo head gasket are not generated.

  In addition, since the step 9 is formed over the entire circumference of the bore portion 5 as a height corresponding to the thickness of the head gasket provided at the time of assembling the internal combustion engine, The part 5 can be reliably deformed. Therefore, when the cylinder block 1 is assembled to the internal combustion engine, the bore portion 5 can be processed with high accuracy so as to have a predetermined roundness. Further, since the step 9 is cut and the deck surface 2 of the cylinder block 1 is processed to be flat after the processing of the bore portion 5 is finished, the reliability of the head gasket may be lowered when assembled to the internal combustion engine. Absent.

  The present invention is not limited to the above-described embodiment, and various modifications or changes can be made without departing from the spirit of the invention. For example, in the above-described embodiment, the cylinder block 1 to be processed has an open deck structure in which the water jacket 7 is opened to the deck surface 2, but the present invention is an air-cooled cylinder block without a closed deck structure or a water jacket. It is also applicable to the processing of. In addition, the step 9 formed in the cylinder block 1 can be formed at the periphery of the bore portion 5 if the dummy head 1 can be deformed by applying a load to the bore portion 5 equivalent to that when the cylinder head is assembled. You may form in a part or the position away from the bore part 5. FIG. Further, the step 9 after the processing of the bore portion 5 can be left as it is or depending on the specification of the head gasket interposed when the cylinder head is assembled, or the protruding tip portion can be cut and remain.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Deck surface 3 Head bolt 5 Bore part 6 Cylinder liner 7 Water jacket 8 Bolt hole 9 Step 11 Dummy head 12 Through-hole 13 Bolt through-hole

Claims (4)

  A bore portion of the cylinder block is formed on the deck surface of the cylinder block constituting the internal combustion engine by projecting in a direction of assembly of the cylinder head constituting the internal combustion engine to form a step, and a dummy head is assembled on the deck surface with a bolt. Is processed in a state of being deformed through the step, and a cylinder block machining method characterized by:   2. The cylinder according to claim 1, wherein the step is formed at a peripheral edge of the bore portion as a height corresponding to a thickness of a head gasket provided on the deck surface when the internal combustion engine is assembled. Block processing method.   3. The cylinder block machining method according to claim 2, wherein after the machining of the bore portion is finished, the step is cut and the deck surface is machined flat. 4.   The cylinder block manufactured by the processing method of any one of Claims 1-3.

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