JP3046195B2 - Timing chain lubrication system for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine for rotating a crankshaft to one or both of an intake valve camshaft and an exhaust valve camshaft, or to a fuel injection pump or the like. The present invention relates to a lubricating device for the timing chain when transmitted via the timing chain.

[0002]

2. Description of the Related Art Conventionally, lubrication of a timing chain has been disclosed in, for example,
As described in Japanese Patent No. 98419 and the like, lubricating oil from a lubricating oil driven by an internal combustion engine is blown directly onto the timing chain by jetting from an oil jet. .

[0003] However, the lubricating oil is sprayed from the oil jet to the timing chain as described above. In addition to the necessity of the oil jet, the oil jet is used in a cylinder block or the like. Or, parts such as bolts for attaching to the cover case covering the timing chain are also required, and not only the number of parts is large, but also the lubricating oil from the lubricating oil pump is attached to these to the cylinder block or the cover case. A lubricating oil passage for leading to the oil jet must be formed, in other words, the number of parts, the number of assembling steps, and the number of processing steps are increased. There is a problem that not only the size is greatly increased but also the size is increased.

In addition, the diameter of the nozzle hole in the oil jet must be relatively large so that the supply of lubricating oil to the timing chain can be ensured even in the low rotation speed range. The ratio of the lubricating oil ejected from the oil jet out of the lubricating oil from the oil jet increases, and there is also a problem that the lubricating oil supplied to various operating parts in the internal combustion engine becomes insufficient.

According to the present invention, a lubricating oil pump and a crankshaft cover a timing chain in a recent internal combustion engine as disclosed in Japanese Patent Application Laid-Open Nos. 5-59924 and 5-33688. Attention is paid to the point that it is proposed to support and provide the cover case at a portion penetrating the cover case, and by utilizing this, the timing chain can be reliably prevented without causing the above-described conventional problem. An object of the present invention is to provide a device that can be lubricated.

[0006]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention relates to a method of forming a coil on one side of a cylinder block between a sprocket on a crankshaft and a sprocket on a camshaft or a fuel injection pump shaft. A cover case that covers the hung timing chain is joined, and a pump casing of a lubricating oil pump is provided in a portion of the cover case through which the crankshaft penetrates. In the casing, an inner rotor fitted to the crankshaft and the inner rotor are provided. An inner rotor and an outer rotor, which are inserted from the inside of the cover case, and further, on the inner surface of the cover case, a flat cover plate is attached so as to close the pump casing with the cover plate, A discharge chamber for the inner rotor and the outer rotor is located at a position above the crankshaft. On the other hand, a minute gap is provided between the lid plate and the inner rotor so that the discharge chamber communicates with a portion near the start of engagement of the timing chain with the sprocket when viewed from the axial direction of the crankshaft. ".

[0007]

[Operation] With this configuration, a part of the high-pressure lubricating oil in the discharge chamber of the lubricating oil pump is ejected through the minute gap to a location near the start of engagement of the timing chain with the sprocket. Thus, the lubricating oil can be reliably supplied to the portion where the timing chain starts to mesh with the sprocket without providing an oil jet and a lubricating oil passage for the lubricating oil as in the related art.

[0008] The pressure of the lubricating oil in the discharge chamber increases in proportion to the rotation speed of the internal combustion engine. When the pressure of the lubricating oil in the discharge chamber increases, the flat lid plate is caused by this pressure. In this case, the minute gap is deformed so as to increase, in other words, the minute gap automatically increases in proportion to the rotation speed of the internal combustion engine, so that the lubricating oil from the minute gap is increased. Can be restricted to a very small amount in a low rotation range, and thereafter, can be increased in proportion to the rotation speed.

[0009]

Therefore, according to the present invention, the cost required for lubricating the timing chain can be greatly reduced, and the size and weight can be reduced. The amount of lubricating oil to be controlled can be regulated to a very small amount in the low rotation range, so that the lubricating oil can be sufficiently supplied to the timing chain in the high rotation range, but in the low rotation range, This has the effect of reliably preventing a shortage of lubricating oil supply to various operating parts in the internal combustion engine.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure, reference numeral 1 denotes a cylinder block, and reference numeral 2 denotes a crankshaft that is supported by a bearing 3 in the cylinder block 1. A side surface 1a of the cylinder block 1 has a timing chain 4 described later. Cover case 5 covering the whole of
The cover case 5 and the cylinder block 1 are detachably joined by a plurality of bolts (not shown).
An oil pan 6 is joined to a lower portion of the oil pan.

The shaft end 2a of the crankshaft 2 is
A power transmission pulley 7 for an engine accessory such as a cooling water pump (not shown) is fitted to the protruding end of the shaft end 2a. A sprocket 8 is fitted to a portion inside the cover case 5, and the timing chain 4 for transmitting power to a camshaft (not shown) is wound around the sprocket 8.

A recess 9 is provided on the side of the power transmission pulley 7 on the side of the cover case 5, and a lubricating oil pump 10 provided on the side plate 5 a of the cover case 5 is disposed in the recess 9. Set up. This lubricating oil pump 10
The side surface plate 5a of the cover case 5 extends from the recess 9
Pump casing 10a integrally formed inward
An outer rotor 10b inserted into the pump casing 10a from within the cover case 5, and an inner rotor 10 fitted to a shaft end 2a of the crankshaft 2.
c, on the inner surface of the side plate 5a of the cover case 5, so as to cover the entire pump casing 10a,
A flat cover plate 10e removably attached with a plurality of bolts 10d disposed around.

The pump casing 10a and the cover plate 10e of the lubricating oil pump 10 have the outer rotor 1
0b and suction chamber 10f for inner rotor 10c
And a discharge chamber 10g, and a suction passage 10 communicating with the suction chamber 10f is formed in the lid plate 10e.
h, and a discharge passage 10i communicating with the discharge chamber 10g is formed. The lubricating suction pipe 11 from the oil pan 6 is connected to the suction passage 10h.
The discharge passage 10i is connected to a main lubricating oil passage (not shown) in the cylinder block 1.

The cover plate 10 of the lubricating oil pump 10
e, the discharge chamber 10g is disposed at a position above the shaft end 2a of the crank 2, and a small gap 12 is formed between the cover plate 10e and the inner rotor 10c. The timing chain 4 is provided so as to communicate with a portion near the start of engagement with the sprocket 8 when viewed from the axial direction of FIG.

In this configuration, the lubricating oil pump 10 sucks the lubricating oil in the oil pan 6 by the rotation of the crankshaft 2 accompanying the start of the internal combustion engine, and then the discharge passage 1
From 0i, it is sent out to the main lubricating oil passage 12 in the cylinder block 1 at a high pressure. in this case,
A part of the high pressure lubricating oil in the discharge chamber 10g of the lubricating oil pump 10 is ejected through the minute gap 12 to a position near the start of the engagement of the timing chain 4 with the sprocket 8, so that the sprocket of the timing chain 4 The lubricating oil can be reliably supplied to the portion where the engagement with the gear 8 starts.

The pressure of the lubricating oil in the discharge chamber 10g increases in proportion to the number of revolutions of the internal combustion engine. When the pressure of the lubricating oil in the discharge chamber 10g increases, this pressure causes The plate 10e is deformed so that the minute gap 12 becomes large,
In other words, the minute gap 12 automatically increases in proportion to the rotational speed of the internal combustion engine, so that the amount of lubricating oil ejected from the minute gap 12 is reduced to a very small amount in a low rotation range. While it can be regulated, it can thereafter increase in proportion to the rotational speed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 1a One side of cylinder block 2 Crankshaft 2a Shaft end of crankshaft 4 Timing chain 5 Cover case 6 Oil pan 10 Lubricating oil pump 10a Pump casing 10b Outer rotor 10c Inner rotor 10e Cover plate 10f Suction chamber 10g Discharge chamber 12 Micro Gap

Claims (1)

(57) [Claims] 1. A cover case for covering a timing chain wound around a sprocket on a crankshaft and a sprocket on a camshaft or a fuel injection pump shaft is joined to one side surface of a cylinder block. In a portion where the crankshaft penetrates, a pump casing of the lubricating oil pump is provided, and an inner rotor fitted to the crankshaft and an outer rotor for the inner rotor are inserted into the casing from the inside of the cover case,
Further, in an internal combustion engine in which a flat cover plate is attached to the inner surface of the cover case so as to close the pump casing with the cover plate, a discharge chamber for the inner rotor and the outer rotor is provided above the crankshaft. A minute gap between the lid plate and the inner rotor, the discharge chamber communicating with the portion near the start of engagement of the timing chain with the sprocket when viewed from the axial direction of the crankshaft. A lubricating device for a timing chain in an internal combustion engine.