JP3146797B2 - Engine lubrication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an engine lubrication device.

[0002]

2. Description of the Related Art In an engine lubrication system, lubricating oil pumped by an oil pump lubricates a crankshaft portion, and then lubricates a cylinder head portion through an oil passage provided in a cylinder block, and finally lubricates the lubricating oil. The oil falls freely and is returned to the oil pan. A relief valve is provided in the course of the forced lubrication path in which the lubricating oil is forcibly lubricated by being fed by the oil pump, so that the pressure of the forced lubricating oil does not exceed a specified value. The lubricating oil relieved from the relief valve is used effectively for lubrication of the timing chain.

FIG. 5 shows an example of a timing chain. A timing chain 4 is mounted on the cam timing sprockets 1 and 2 and the idle sprocket 3, and a timing chain 7 is mounted on another idler sprocket 5 and a crank timing sprocket 6 provided coaxially with the idler sprocket 3. ing. Then, the rotation of the crankshaft 8 is transmitted to the idler sprocket 5 via the timing chain 7, and this rotation is transmitted to the cam timing sprockets 1 and 2 via the timing chain 4 by the idler sprocket 3. I have.

The rotation of the crankshaft 8 is transmitted to an oil pump drive sprocket 10 via an oil pump drive chain 9 to drive an oil pump (not shown). The lubricating oil pumped by the oil pump lubricates the lubricating portion of the crankshaft 8, and then lubricates the lubricating portions of the camshafts 13 and 14 via oil passages formed in the cylinder blocks 11 and 12, and thereafter frees the lubricating portion. It falls and is returned to an oil pan (not shown). Although not shown in the figure, a relief valve is provided in the middle of the lubrication path.

As shown in FIG. 4, a conventional lubrication path is provided with a fixing hole 17 for inserting and fixing a relief valve 16 in a cam housing 15, and a relief valve 16 is inserted and fixed in the fixing hole 17, and this relief valve is provided. A part of the top of the relief valve 16 is pressed by a chain guide 18 so as not to block the escape port provided at the top of the cam 17, and the cam housing 15 is fastened to the cam head 12 together with the chain guide 18 by bolts 19.
In this manner, by fixing the relief valve 16, the oil passage 20 provided in the cylinder head 12 and the inlet side of the relief valve 16 communicate with each other, and when the pressure of the lubricating oil in the oil passage 20 becomes equal to or higher than a specified pressure, The ball 21 is pushed up to release a part of the lubricating oil, and this part of the lubricating oil 22 is guided by the inner surface of the chain guide 18 and reaches the timing chain 4 so as to lubricate the timing chain 4. I have.

In Japanese Utility Model Laid-Open Publication No. 18302/1987, a hole is provided for mounting a relief valve on the axis of an eccentric shaft that supports a power transmission member (sprocket). A relief passage is provided at the side of the sprocket, and when the pressure of the oil passage provided at the axis of the eccentric shaft becomes higher than a specified pressure, the relief valve opens and a part of the oil flows into the relief passage. A lubrication system that lubricates the sprocket by applying a part of the escaped oil to the deflection plate attached to the boss of the sprocket, turning the oil ejection direction to the sprocket side and applying the oil to the sprocket. Is disclosed. To assemble this lubricating device, a turning plate is attached to the sprocket, a relief valve is inserted into a hole provided in the eccentric shaft, and a bolt is screwed into a screw hole formed at the inlet of this hole, thereby forming a relief. The valve is fixed in the hole.

Japanese Utility Model Laid-Open No. 3-123922 discloses a crankshaft sprocket in which a hollow boss portion is integrally fixed to a crankshaft which is supported through a main casing of a water pump. Between the sprocket and the main body casing, a tubular body for inserting and fixing a relief valve integrally formed with a relief passage is provided, and when the pressure of the oil in the relief passage becomes equal to or higher than a specified pressure, the relief valve is opened, There is disclosed a lubricating device in which oil released from a relief valve is applied to a crankshaft sprocket through a second through hole opened in a side surface of a cylindrical body to lubricate a crankshaft sprocket portion.

[0008]

In the conventional lubricating apparatus described above, in the conventional example shown in FIG. 4, a relief port for the relief valve is provided at the top of the relief valve, and a part of the relieved lubricating oil is guided to the chain guide. Since the relief valve is fixed to the top of the relief valve by pressing the top with a chain guide, the relief valve cannot have a sufficient opening area. For this reason, for example, when the engine is started, the lubricating oil has a high viscosity at a low lubricating oil temperature, so that even if the lubricating oil pressure is higher than a specified value, sufficient relief cannot be performed, and the function of the relief valve is not sufficient. There is a problem that can not be fully exhibited.

Further, the lubricating device disclosed in Japanese Utility Model Laid-Open Publication No. 18302/1987 requires a dedicated bolt for attaching the diverting plate and fixing the relief valve. As a result, the weight increases,
There is a problem that man-hours for processing and assembly are increased. Similarly, the lubricating apparatus disclosed in Japanese Utility Model Laid-Open Publication No. 3-123922 also requires a complicated tubular portion having a relief passage formed therein. There is a problem that many man-hours are required for assembly.

[0010] The present invention provides an engine which solves the above-mentioned problem by making the relief valve opening area of the relief valve sufficiently large so as not to impair the function of the relief valve and simplifying the installation of the relief valve. A lubrication device is provided.

[0011]

According to the present invention, there is provided an engine lubrication system comprising a relief valve provided in a cam housing of an engine in an engine lubrication system. A relief port is provided, and the shape of the cam housing to which the relief valve is attached is U-shaped so that the relief port of the relief valve is released, and the opening direction of the U-shape is set to the timing chain direction. is there.

[0012]

According to the present invention, the following operations are provided. That is, since the relief port is provided on the side of the relief valve provided in the cam housing of the engine, the relief port is not blocked even if the top of the relief valve is pressed and fixed, and the relief valve has a relief port opening area. It can be made arbitrarily large. Further, since the relief housing has a U-shape in which the relief opening of the relief valve is opened, the relief opening of the relief valve can be provided on the side surface of the relief valve. Since the opening direction of the U-shape is set to the direction of the timing chain, the lubricating oil relieved from the relief port of the relief valve can be guided to the U-shaped opening and applied to the chain, making it possible to effectively lubricate the chain. Become. The mounting of the relief valve is performed by inserting it into a U-shaped hole formed in the cam housing and pressing the top thereof.

[0013]

An embodiment of the present invention will be described below. FIG. 3 is a longitudinal sectional view taken along the line AA of FIG. 5, which is an example of a timing chain. Reference numerals 1 and 2 denote cam timing sprockets, reference numerals 3 and 5 denote idler sprockets, and reference numeral 6 denotes a crank timing sprocket. The relief valve 16 is inserted into a U-shaped portion, which will be described later, provided on the cam housing 15, and is fastened and fixed to the cylinder head 12 by a bolt 19 so that a top portion thereof is pressed by a chain guide 18.

[0014] Figure 1 is a view showing an enlarged portion of the relief valve 16 in FIG. 3, and a lower bottom portion 23 of a height H ₁ is formed in the cam housing 15, a plane as seen from the direction of arrow X As shown in FIG. 2, a U-shaped rib 24 surrounding both sides of the bottom portion 23 is formed. The height H ₂ of the boss 25 into which the bolt 19 is inserted is substantially equal to the height of the relief valve 16. A fixing hole 17 into which the relief valve 16 is inserted is formed in a bottom (valley) of the U-shaped rib 24 of the bottom 23.

On the other hand, a relief hole 26 is provided on a side surface of the relief valve 16 at a position higher than the bottom portion 23 of the cam housing 15. In the present embodiment, a plurality of the relief holes 26 are provided on the outer periphery of the relief valve 16, and the direction in which the relief valve 16 is attached is arbitrary, and the opening area of the relief hole 26 of the relief valve 16 is sufficiently increased. We can secure it. The flange portion 27 of the chain guide 18 is long enough to press the top of the relief valve 16 over substantially the entire surface.

The operation of the embodiment constructed as described above will now be described. First, assembling the relief valve 16 itself only requires inserting the relief valve 16 into the fixing hole 17 provided in the cam housing 15, and thereafter, combining the chain guide 18 and the cam housing 15 together with the bolt 19 to the cylinder head 12.
, The assembly of the chain guide 18 and the cam housing 15 is performed at the same time. Since the height of the boss portion 25 of the cam housing 15 is substantially equal to the height of the relief valve 16, the length of the flange portion 27 of the chain guide 18 is a length that closes the top of the relief valve 16,
The top of the relief valve 16 is pressed into contact with the flange portion 27 of the chain guide 18 in a state of being fitted into the fixing hole 17, and is mounted so as to face an oil passage 20 formed in the cylinder head 12.

A relief port 26 is provided on the side of the relief valve 16.
Since the relief valve 16 is provided, even if the entire top of the relief valve 16 is pressed and fixed, the relief port 26 is not closed, and the opening area of the relief port 26 of the relief valve 16 can be arbitrarily increased. Then, to lower the height H ₁ of the bottom 23 of the cam housing 15 for mounting the relief valve 16, since the relief port 26 of the relief valve 16 is to be released to a position higher than the bottom 23, the relief port of the relief valve 16 26 can be provided on the side surface of the relief valve 16, and a U-shaped rib 24 is provided so as to surround both sides of the bottom portion 23, and the opening direction of the U-shaped rib 24 is set to the direction of the timing chain 4. The lubricating oil 22 relieved from the relief port 26 of the relief valve 16 can be guided to the U-shaped rib 24 and applied to the chain 4,
The lubrication of the chain 4 can be performed effectively.

The lubricating oil 22 jetted in a direction opposite to the chain 4 from a plurality of escape holes 26 provided on the side surface of the relief valve 16.
Is ejected into the space surrounded by the ribs 24 and the chain guide 18, and is thus collected by the oil pan without being scattered around. Alternatively, by making the relief hole 26 provided on the side surface of the relief valve 16 a sufficiently large hole only in the chain 4 direction, the entire amount of the relieved lubricating oil 22 can be ejected in the chain 4 direction.

[0019]

As described above in detail, according to the present invention, the shape of the cam housing for mounting the relief valve is U-shaped so that the relief port of the relief valve is opened, so that the relief port of the relief valve is formed on the side of the relief valve. Can be provided.
As a result, the opening area of the relief port can be made sufficiently large, and the function of the relief valve can be maintained even if the temperature of the lubricating oil is low.

Since the direction of the U-shaped opening is set in the direction of the timing chain, the lubricating oil relieved from the relief port of the relief valve can be inserted into the U-shaped opening without using a special part such as a deflection plate. The chain can be guided and applied to the chain, and the chain can be effectively lubricated.

Further, since the mounting of the relief valve itself only needs to be inserted into the hole of the U-shaped portion formed in the cam housing, there are no parts for mounting the relief valve, and the number of parts is reduced to reduce the weight and In addition, processing and assembling steps can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is a plan view seen from the direction of arrow X in FIG.

FIG. 3 is an overall view showing a state in which the embodiment shown in FIG. 1 is applied in a longitudinal section taken along line AA of FIG. 5;

FIG. 4 is an enlarged longitudinal sectional view showing a main part of a conventional example.

FIG. 5 is a front view showing an example of a timing chain.

[Description of sign]

 12 Cylinder head 15 Cam housing 16 Relief valve 18 Chain guide 23 Bottom 24 Rib 26 Release hole

Claims (1)

(57) [Claims] 1. An engine lubrication system comprising a relief valve provided on a cam housing of an engine in an engine lubrication system, wherein a relief port is provided on a side surface of the relief valve, and the shape of the cam housing to which the relief valve is attached is set to the shape described above. An engine lubricating device, wherein the relief valve has a U-shape in which a relief opening is opened, and the opening direction of the U-shape is set in a timing chain direction.