JP2010270682A - Oil return passage for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a passage for passing oil while suppressing an increase of cost and a loading space. <P>SOLUTION: The oil return passage 65 passing oil lubricating sliding parts of the engine 1 through a cylinder 3 and a cylinder block 2 and sending it down to an oil pan includes a main passage 651 including a large diameter part 651a at an upstream side and a small diameter part 651b at a downstream side, and a branch passage 652 branched off from the large diameter part 651a and passing through a portion with a diameter larger than the small diameter 651b and raised higher in temperature than that of the small diameter part 651b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine oil return passage.

  There is an oil temperature adjusting device that adjusts the oil temperature by cooling the oil by causing the oil to flow through a bypass path close to the water jacket of the cylinder block at a high oil temperature (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 1-63708

  However, in the above-described conventional example, the oil flow rate to the bypass passage is adjusted by the flow rate control valve. For this reason, the number of parts increases by the amount corresponding to the flow control valve, which increases the cost and mounting space.

  The present invention has been made paying attention to such a conventional problem, and an object thereof is to control a passage through which oil flows while suppressing an increase in cost and mounting space.

  The present invention solves the above problems by the following means. In order to facilitate understanding, reference numerals corresponding to the embodiments of the present invention are given, but the present invention is not limited thereto.

  The present invention is an oil return passage (65) through which oil for lubricating a sliding portion of an engine (1) flows down to an oil pan through a cylinder head (3) and a cylinder block (2), and has a large diameter portion on the upstream side. (651a), a main passage (651) having a small-diameter portion (651b) on the downstream side, and a branch from the large-diameter portion (651a), larger than the diameter of the small-diameter portion (651b) and larger than the small-diameter portion (651b) And a branch passage (652) that passes through the portion that becomes high in temperature.

  According to the present invention, the oil that has flowed down the large-diameter portion of the main passage can be temporarily stored in the large-diameter portion upstream of the small-diameter portion where the passage cross-sectional area decreases.

  At this time, when the oil temperature is high and the viscosity is low, the amount of oil flowing into the small diameter portion having a small diameter is small, so that the amount of oil accumulated in the large diameter portion increases. Therefore, the oil can be stored up to the branch passage that branches from the large diameter portion. After accumulating up to the branch passage, the oil flowing down the large diameter portion of the main passage flows down to the oil pan through the branch passage.

  On the other hand, at a high oil temperature with a low viscosity, the oil temporarily accumulates, but since the oil flow rate flowing down to the small diameter portion is large, the oil does not accumulate to the branch passage. Therefore, the oil that has flowed down the large diameter portion of the main passage can flow down to the oil pan through the small diameter portion.

  Therefore, a passage through which oil flows can be controlled according to the oil temperature without using a flow control valve, and an increase in cost and mounting space can be suppressed.

It is a schematic block diagram of the engine by 1st Embodiment. It is detail drawing of the cylinder head part of the oil return path by 1st Embodiment. It is the top view which looked at the cylinder head by a 1st embodiment from the cylinder block side. It is detail drawing of the cylinder head part of the oil return path by 2nd Embodiment.

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

(First embodiment)
FIG. 1 is a schematic configuration diagram of an engine 1 according to the present embodiment.

  The engine 1 includes a cylinder block 2, a cylinder head 3, an oil pan 4, a front cover 5, and a lubrication device 6.

  The cylinder block 2 is configured by integrally casting a plurality of cylinders and a crankcase, and supports a piston, a crankshaft, and the like.

  The cylinder head 3 is provided on the upper surface of the cylinder block 2. The cylinder head 3 is provided with an intake valve and an exhaust valve, and is also provided with a valve operating apparatus including a camshaft for driving them.

  The oil pan 4 is provided on the lower surface of the cylinder block 2. The oil pan 4 stores oil that lubricates sliding parts of each part of the engine.

  The front cover 5 is provided on the front surface of the engine 1. The front cover 5 protects each belt and auxiliary equipment provided on the front surface of the engine 1.

  The lubricating device 6 includes an oil strainer 61, an oil pump 62, a main oil gallery 63, a cylinder head oil gallery 64, and an oil return passage 65.

  The oil strainer 61 is provided inside the oil pan 4. The oil strainer 61 removes foreign matters in the oil.

  The oil pump 62 is driven by a crankshaft via a belt, and sucks up and discharges oil inside the oil pan 4.

  The main oil gallery 63 is an oil passage formed inside the cylinder block 2 in the cylinder row direction. The main oil gallery 63 is formed with a plurality of oil supply holes that open toward the in-block sliding portion such as the crankshaft bearing portion. The oil pumped from the oil pump 62 to the main oil gallery 63 is ejected from the oil supply hole and supplied to the sliding portion in the block.

  The cylinder head oil gallery 3 is connected to the main oil gallery 63 and is an oil passage formed inside the cylinder head 3 in the cylinder row direction. The cylinder head oil gallery 3 is formed with a plurality of oil supply holes that open toward an in-head sliding portion such as a camshaft. The oil that has been pressure-fed through the main oil gallery 63 to the cylinder head oil gallery 3 is ejected from the oil supply hole and supplied to the in-head sliding portion.

  The oil return passage 65 is a passage for returning the oil that has lubricated the sliding portion in the head to the oil pan 4, and is formed from the cylinder head 3 to the cylinder block 2. Hereinafter, the details of the oil return passage 65 will be described with reference to FIG.

  FIG. 2 is a detailed view of the cylinder head portion of the oil return passage 65. The arrow in the figure indicates the oil falling direction.

  The oil return passage 65 includes a main passage 651 and a branch passage 652.

  The main passage 651 includes a large diameter portion 651a and a small diameter portion 651b.

  Oil that has lubricated the sliding portion in the head flows down to the large diameter portion 651a.

  The small diameter portion 651b is formed downstream of the large diameter portion 651a. The small diameter portion 651b is a passage having a smaller diameter than the large diameter portion 651a. The small diameter portion 651b is provided such that the axial center of the small diameter portion 651b is located in the vicinity of the axial center of the large diameter portion 651a.

  The branch passage 652 branches from the large diameter portion 651a of the main passage 651. In other words, it branches off from the main passage 651 upstream (cylinder head side) from the small diameter portion 651b. The diameter of the branch passage 652 is smaller than the large diameter portion 651a of the main passage 651 and larger than the small diameter portion 651b of the main passage 651. The branch passage 652 branches from the large-diameter portion 651a of the main passage 651 so that the axial center of the branch passage 652 is at a position eccentric in the radial direction by a predetermined amount from the axial center of the large-diameter portion 651a of the main passage 651. .

  With such a configuration, since the cross-sectional area of the small-diameter portion 651b is smaller than the cross-sectional area of the large-diameter portion 651a, the oil that has flowed down the large-diameter portion 651a is temporarily accumulated in the main passage 651 upstream of the small-diameter portion 651b. be able to. Hereinafter, the portion of the main passage 651 in which the oil is temporarily stored is referred to as an “oil storage portion 653”.

  FIG. 3 is a plan view of the cylinder head 3 as viewed from the cylinder block 2 side.

  As shown in FIG. 3, the oil return passage 65 is formed at the outer edge of the cylinder head 3 between the combustion chamber 31a and the combustion chamber 31b and between the combustion chamber 31b and the combustion chamber 31c. The small diameter portion 651b of the main passage 651 is formed at a position farther from the water jacket 32 through which the high-temperature cooling water around the combustion chamber or around the combustion chamber flows than the branch passage 652. As described above, the small diameter portion 651b of the main passage 651 is formed so as to pass through a relatively low temperature portion of the engine body, and the branch passage 652 is formed so as to pass through a relatively high temperature portion of the engine body.

  Next, the function and effect of the lubricating device 6 according to the present embodiment will be described with reference to FIGS. 1 to 3 again.

  As shown in FIG. 1, the oil in the oil pan 4 sucked up by the oil pump 62 through the oil strainer 61 is pumped to the main oil gallery 63 and the cylinder head oil gallery 3, and slides in the block and the head Supplied to the inner sliding part and lubricates each sliding part.

  Part of the oil that has lubricated the sliding portion in the head is returned to the oil pan 4 through the oil return passage 65. At this time, as shown in FIG. 2, the oil that has flowed down the large-diameter portion 651a of the main passage 651 temporarily accumulates in the oil reservoir portion 653 upstream of the small-diameter portion 651b having a small diameter.

  Here, when the oil temperature is relatively low and the viscosity of the oil is large, the amount of oil flowing through the small diameter portion 651b having a small diameter becomes small, so that the oil accumulates in the oil reservoir portion 653, and the branch passage 652 When accumulated to the height, it flows into the branch passage 652 having a large diameter and returns to the oil pan 4.

  On the other hand, when the oil temperature is relatively high and the viscosity of the oil is small, although the oil temporarily accumulates in the oil reservoir 653, the amount flowing into the small-diameter portion 651b having a small diameter is relatively large. Oil does not collect up to a height of 652. Therefore, most of the oil that has flowed down the large diameter portion 651a can be returned to the oil pan 4 through the small diameter portion 651b.

  Thus, according to the present embodiment, whether to return the oil to the oil pan 4 through the branch passage 652 or to the oil pan 4 through the small diameter portion 651b of the main passage 651 according to the oil temperature without using a control valve. Can be controlled. Therefore, the cost can be reduced as compared with the case where the control valve is provided, and the engine 1 can be downsized because the mounting space is not required.

  As shown in FIG. 3, in this embodiment, the branch passage 652 is provided at a position closer to the water jacket 32 through which the high-temperature cooling water around the combustion chamber flows than the small diameter portion 651 b of the main passage 651.

  Therefore, the temperature of the oil can be raised while flowing through the branch passage 652, and the viscosity of the oil can be lowered to an appropriate viscosity at an early stage. Thereby, the friction loss in an engine sliding part can be reduced at an early stage. In addition, the temperature of the oil flowing through the small diameter portion 651b can be maintained at an appropriate viscosity without excessively increasing the temperature. Thereby, the oil film breakage of the engine sliding portion can be suppressed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. The second embodiment of the present invention differs from the first embodiment in that the branch location of the branch passage 652 is changed. Hereinafter, the difference will be described. In each embodiment described below, the same reference numerals are used for portions that perform the same functions as those of the above-described embodiment, and repeated description is appropriately omitted.

  FIG. 4 is a detailed view of the cylinder head portion of the oil return passage 65 according to the present embodiment. The arrow in the figure indicates the oil falling direction.

  As shown in FIG. 4, in this embodiment, the branch passage 652 is branched from the side surface of the large diameter portion 651 a of the main passage 651. As a result, the same effects as in the first embodiment can be obtained, and the opening of the branch passage 652 is perpendicular to the oil falling direction, so that the oil can be prevented from flowing into the branch passage 652 at a high oil temperature.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  For example, the number of branch passages 652 may be increased.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder block 3 Cylinder head 4 Oil pan 31a Combustion chamber 31b Combustion chamber 31c Combustion chamber 65 Oil return passage 651 Main passage 651a Large diameter portion 651b Small diameter portion 652 Branch passage

Claims (4)

An oil return passage for flowing oil that lubricates the sliding portion of the engine down to the oil pan through the cylinder head and the cylinder block;
A main passage having a large diameter portion on the upstream side and a small diameter portion on the downstream side;
A branch passage that branches from the large-diameter portion, passes through a portion that is larger than the diameter of the small-diameter portion, and that is hotter than the small-diameter portion;
An oil return passage for an engine characterized by comprising: 2. The engine oil return passage according to claim 1, wherein the branch passage passes through a position closer to the combustion chamber than a small-diameter portion of the main passage. The said branch channel | path opens to the large diameter part of the said main path so that it may become substantially right angle with respect to the falling direction of the oil which flows down the large diameter part of the said main path. Engine oil return passage. The oil return passage for an engine according to any one of claims 1 to 3, wherein the main passage shifts from a large diameter portion to a small diameter portion in the cylinder head.

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