JP2019108851A - Method for manufacturing cylinder block - Google Patents

Abstract

To reduce concerns that a temperature of engine oil varies on a low temperature side, and suppress deterioration of fuel economy.SOLUTION: Engine oil 18 supplied to a cylinder head 14 is dropped to an oil pan 16 through an oil drop passage part 24 formed in a cylinder block 12. On an inner wall of the oil drop passage part 24, a thick resin layer 26 is formed by injection molding or blow molding.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a cylinder block, and more particularly to a method of manufacturing a cylinder block having an oil dropping passage for dropping oil supplied to a cylinder head to an oil pan.

  An example of this type of manufacturing method is disclosed in Patent Document 1. According to this document, a fluorine resin such as polytetrafluoroethylene is coated on the inner wall of the oil return hole which returns the oil supplied from the oil pan to the valve operating chamber to the oil pan. As a result, it becomes difficult for carbon-containing substances contained in the blowby gas or oil to adhere to the inner wall of the oil return hole.

Utility model registration 3176727

  However, Patent Document 1 attempts to prevent adhesion of carbon-containing substances to the inner wall by coating a thin film of liquid paint or powder paint, and it can not be expected that the thin film has heat insulation performance. As a result, in the technique of Patent Document 1, the degree of cooling of the oil in the oil dropping passage may vary due to heat transfer from the inner wall cooled by the outside air, and the temperature of the oil may vary.

  Therefore, the main object of the present invention is to provide a method of manufacturing a cylinder block capable of suppressing the deterioration of fuel consumption by reducing the concern that the temperature of the oil in the dropping passage varies and appropriately managing the discharge oil temperature. It is to be.

  A method of manufacturing a cylinder block according to the present invention is a method of manufacturing a cylinder block having an oil dropping passage for dropping oil supplied to a cylinder head to an oil pan, and resin is formed on the inner wall of the oil dropping passage by injection molding or blow molding. It is a manufacturing method of a cylinder block made to form a layer.

  By performing injection molding or blow molding, a thick resin layer can be formed on the inner wall of the oil removal passage. As a result, due to the heat transfer from the inner wall, the degree of cooling of the oil in the oil dropping passage varies, which in turn reduces the concern that the temperature of the oil varies.

  The above object, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments given with reference to the drawings.

It is an illustration figure which shows the principal part structure of the engine of this Example. (A) is an illustrative view showing a casting and lower treatment process, (B) is an illustrative view showing a mold attaching process, and (C) is an illustrative view showing a resin injection process. (A) is an illustration figure which shows a casting * lower-treatment process, (B) is an illustration figure which shows a blow molding preparatory process, (C) is an illustration figure which shows a blow molding process.

  Referring to FIG. 1, the engine 10 of this embodiment is an engine mounted on a vehicle, and includes a cylinder block 12. The cylinder head 14 is mounted on the upper portion of the cylinder block 12, and the oil pan 16 in which the engine oil 18 is stored is disposed on the lower portion of the cylinder block 12. Here, the cylinder block 12 and the cylinder head 14 are made of metal (made of aluminum), and the oil pan 16 is made of resin. The oil pan 16 may have a resin layer formed on the surface of a metal base as long as it exhibits heat insulation performance.

  The cylinder block 12 includes a cylinder bore 20 in which a piston (not shown) is accommodated, a water jacket 22 filled with cooling water for cooling the cylinder bore 20, and oil for dropping the engine oil 18 supplied to the cylinder head 14 into the oil pan 16. It has a drop passage portion 24 and a crank chamber 28 in which a crankshaft (not shown) is housed.

  The cylinder bore 20, the water jacket 22 and the oil dropping passage 24 extend downward from the top surface of the cylinder block 12. However, while the cylinder bore 20 and the oil dropping passage 24 reach the crank chamber 28, the water jacket 22 has a bottom below the cylinder bore 20.

  When the cylinder block 12 is viewed from above, the cylinder bores 20 draw a true circle of the same diameter, and the water jacket 22 is formed so as to surround the true circle. Also, the oil dropping passage 24 is formed on the outside of the water jacket 22.

  The engine oil 18 stored in the oil pan 16 is discharged by an oil pump (not shown), receives heat in the process of lubricating the parts of the cylinder head and the cylinder block, and is cooled by the cooling water circulating in the engine. After warming up, the engine oil 18 is subjected to heat exchange with cooling water at 80 ° C. to 100 ° C., whereby the temperature of the engine oil 18 is maintained at an appropriate temperature around 110 ° C. However, during high load traveling, even if the temperature of the coolant is controlled, the temperature of the engine oil 18 tends to rise due to the heat load of the engine 10. It is effective to provide an oil cooler in order to suppress the rise in oil temperature due to the increase in heat load of the engine and to maintain the optimum oil temperature.

  Since the cylinder block 12 is made of metal having excellent thermal conductivity, when the outside air temperature is transmitted to the engine oil 18 in the oil dropping passage 24 via the cylinder block 12, the temperature of the engine oil 18 fluctuates on the low temperature side There is a concern (because the outside temperature is low relative to the oil temperature). For example, in winter, engine oil 18 is excessively cooled. In addition, it is impossible to adjust the temperature of the subcooled engine oil 18 to an appropriate temperature by the oil cooler.

  Therefore, in the cylinder block 12 of this embodiment, the thick resin layer 26 is formed on the inner wall of the oil dropping passage 24, and heat transfer is suppressed by enhancing the heat insulation effect of the wall surface. As a result, the outside air temperature accumulated in the inner wall is transmitted to the engine oil 18 in the oil dropping passage 24, and the concern that the temperature of the engine oil 18 varies excessively to the low temperature side is reduced.

  The resin layer 26 is made of polypropylene, nylon or the like and is formed on the inner wall of the oil removal passage 24 by injection molding (strictly, insert molding) or blow molding. When injection molding is performed, the resin layer 26 is formed through the steps shown in FIGS. 2 (A) to 2 (C). Further, when blow molding is performed, the resin layer 26 is formed through the steps shown in FIGS. 3 (A) to 3 (C).

  In the case of injection molding, first, the body of the cylinder block 12 is cast and pretreated in a casting and pretreating process (see FIG. 2A). In the subsequent mold mounting process, the molds 30 and 32 are mounted on the base body of the cylinder block 12 (see FIG. 2 (B)).

  Here, the mold 30 is formed by the passage portion 30a and the main body portion 30b. The passage portion 30 a is slightly smaller than the base body of the cylinder block 12 of the oil dropping passage portion 24 and has a total length slightly longer than the entire length of the oil dropping passage portion 24. On the other hand, the main body portion 30b is larger than the oil dropping passage portion 24, and seals the injection space by fitting the element body of the cylinder block 12 at the lower end of the oil dropping passage 24 portion. Further, the mold 30 is inserted from the side of the crank chamber 28 into the oil dropping passage 24 with the end of the passage portion 30 a facing upward.

  On the other hand, the mold 32 is larger than the passage 30a, and on one end face of the mold 32, there is a recess CC1 shaped to fit with the tip of the passage 30a and a through hole HL1 reaching the side of the mold 32. It is formed. Further, one end of the through hole HL1 is disposed on the outer diameter side of the concave portion CC1. The mold 32 is disposed on the upper side of the cylinder block 12 in a state in which the concave portion CC1 is fitted to the end of the passage portion 30a protruding upward from the oil dropping passage 24.

  In the resin injection process shown in FIG. 2C, the heat-melted resin is injected from the through hole HL1. The injected resin is filled in the gap between the passage portion 30 a and the oil dropping passage 24. When the filled resin hardens, the resin layer 26 is obtained.

  The resin layer 26 is hybrid-bonded (adhesively bonded) to the inner wall surface by the anchor effect in which the resin enters the microscopic unevenness formed on the inner wall surface of the oil dropping passage 24. As a result, noise due to rattling of the resin layer 26 can be prevented. Further, since the resin layer 26 shares the strength of the oil dropping passage portion 24, the thickness and weight of the oil dropping passage portion 24 can be reduced.

  The thickness of the resin layer 26, that is, the amount of heat insulation is defined by the gap between the passage portion 30 a of the mold 30 and the oil dropping passage portion 24. When the hybrid bonding is completed, the upper surface of the body of the cylinder block 12 is processed together with the resin layer 26 by a milling cutter not shown.

  In the case of blow molding, first, the cylinder block 12 in a state in which the resin layer 26 is not formed is cast and pretreated in the casting and pretreating steps (see FIG. 3A). Next, the blow molding device 34 and the cutter 38 are prepared in the blow molding preparation step (see FIG. 3 (B)). Here, the blow molding device 34 is disposed above the oil dropping passage portion 24, and the cutter 38 is disposed at the lower end of the oil dropping passage 24. Further, the heat-softened bottomed parison is inserted from the blow molding device 34 toward the oil dropping passage portion 24.

  In the blow molding process shown in FIG. 3C, air is blown into the bottomed parison. The bottomed parison is pressed against the inner wall surface of the oil dropping passage portion 24 and is hybrid-joined (closely bonded) to the inner wall surface by the anchor effect that the resin enters the microscopic unevenness formed on the inner wall surface. When the bottomed parison solidifies, the cutter 38 cuts off unnecessary resin. As a result, the resin layer 26 is obtained. The thickness of the resin layer 26, that is, the heat insulation amount is adjusted by the blow molding device 34. When the hybrid bonding is completed, the upper surface of the body of the cylinder block 12 is processed together with the resin layer 26 by a milling cutter not shown.

  As described above, the resin layer 26 is formed thick on the inner wall of the oil dropping passage 24 by injection molding or blow molding. As a result, the external air heat accumulated on the inner wall of the oil dropping passage 24 is transmitted to the engine oil 18 in the oil dropping passage 24, and the concern that the temperature of the engine oil 18 disperses excessively to the low temperature side can be reduced. In addition, the amount of oil cooling, which is reduced by enhancing the heat insulation effect of the wall surface and suppressing the heat transfer, is controlled by setting the heat release of the oil cooler more appropriately than by strengthening the cooling system (such as increasing the flow rate of the water pump) Is desirable.

10 ... engine 12 ... cylinder block 14 ... cylinder head 16 ... oil pan 18 ... engine oil 24 ... oil drop passage 26 ... resin layer 30, 32 ... mold 34 ... blow molding device 38 ... cutter

Claims (1)

A manufacturing method of a cylinder block having an oil dropping passage for dropping oil supplied to a cylinder head to an oil pan,
A method for manufacturing a cylinder block, wherein a resin layer is formed on the inner wall of the oil dropping passage by injection molding or blow molding.

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