JPH0771544A - Chain tensioner - Google Patents

Abstract

PURPOSE:To easily secure oil pressure of a hydraulic rush adjuster by providing a first oil passage for connecting a chain tensioner to the bearing part of a cam shaft and a second oil passage for connecting the chain tensioner to the idler bush part of an idler shaft. CONSTITUTION:Lubricating oil which flows in a main oil passage 40 is supplied through a third oil passage 62 to each hydraulic rush adjuster 60 and supplied through a fourth oil passage 64 to a cam chain tensioner adjuster 36. In the adjuster 36, a plunger is slid by pressurized oil to move a pressing part 50 forward and backward, and the pressing force applied to a cam chain is changed to give proper tension. Surplus oil in the adjuster 36 is discharged in such a manner as to direct the fitting surface of the adjuster 36. Some of oil supplied to the adjuster 36 is supplied to a bearing 42 part of each cam shaft through oil passages 44, 66, 68, and supplied to a bush 46 part of an island shaft 28 through an oil passage 48.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chain tensioner, and more particularly to a chain tensioner that secures a hydraulic pressure for adjusting the tension of a chain and a hydraulic lash adjuster.

[0002]

2. Description of the Related Art In an internal combustion engine, a cylinder head is mounted on a cylinder block. A crank bearing cap is attached to the lower portion of the cylinder block. An oil pan is attached to the lower part of the crank bearing cap.

A crankshaft is axially supported by the cylinder block and the crank bearing cap. A crank sprocket, which is a drive side sprocket, is fixedly attached to the front end of the crank shaft.

Intake and exhaust cam shafts are axially supported in parallel with each other on the cylinder head. Intake and exhaust cam sprockets are fixedly attached to the intake and exhaust cam shafts, respectively. A cylinder head cover is attached to the upper part of the cylinder head.

An idler shaft for supporting the timing chain sprocket and the cam chain sprocket, which are integrally formed, is provided in the cylinder head below and in the middle of the intake and exhaust cam sprocket.

A timing chain is wound around the crank sprocket and the timing chain sprocket, and a cam chain is wound around the cam chain sprocket and the intake and exhaust cam sprockets. And constitute a power transmission means which is a chain.

As the chain tensioner, Japanese Patent Laid-Open No.
There is one disclosed in Japanese Patent No. 234954. In the chain tensioner of the internal combustion engine disclosed in this publication, the lubricating oil provided for lubrication between the support shaft and the tensioner bracket drips down to ensure the space between the tip of the adjuster rod and the pad on the tensioner bracket side. There is no need to lubricate and to provide a dedicated lubricating oil passage for the abutting portion, which increases the degree of freedom in designing the cylinder head and the like and makes it compact.

[0008]

By the way, in the conventional internal combustion engine, the hydraulic lash adjuster (HLA, HYDRAULIC LASH) is used when opening and closing the intake and exhaust valves.
ADJUSTER) is used.

As shown in FIGS. 5 to 7, a cam chain tensioner adjuster 136, which is a chain tensioner for adjusting the tension of a chain, for example, a cam chain (not shown), has a pressing portion 150 for contacting the cam chain and applying a tension. A plunger 152 that slides to move the pressing portion 150 forward and backward, a ratchet 154 that suppresses the movement of the plunger 152, a high pressure chamber 156 that slides the plunger 152, and a check ball that adjusts the pressure of the high pressure chamber 156. 157, an oil supply hole 138 for supplying oil into the high pressure chamber 156, and an oil escape hole 158 for discharging excess oil. A timing chain tensioner (not shown) for adjusting the tension of a timing chain (not shown) has substantially the same structure as the cam chain tensioner adjuster 136.

The oil escape hole 158 is provided in the high pressure chamber 1
When the hydraulic pressure is excessively applied to 56, the hydraulic pressure is released, and the tension of the cam chain tensioner adjuster 136 is always maintained in an appropriate state.

The oil flow path of the cylinder head (not shown) of the internal combustion engine is in a state as shown in FIG. That is, the lubricating oil is supplied from the main oil passage 140 to each hydraulic lash adjuster 160, and also to the cam chain tensioner adjuster 136, the idler bush 146, and the bearing 142 of each cam shaft.

An oil lubrication system, which is an oil passage, is arranged in parallel with the main oil passage.

At this time, since the hydraulic lash adjuster is hydraulically driven, there is a risk that the hydraulic lash adjuster may malfunction if the hydraulic pressure drops, and it is necessary to secure a predetermined hydraulic pressure.

Further, the oil escape hole of the cam chain tensioner adjuster is opened in the chain cover in order to always maintain an appropriate hydraulic pressure in the high pressure chamber.
The open end of the oil escape hole is connected to the main oil passage.

As a result, it is difficult to maintain the hydraulic pressures of both the hydraulic lash adjuster and the cam chain tensioner adjuster in an appropriate state, and it is particularly difficult to secure the hydraulic pressure of the hydraulic lash adjuster, which is inconvenient.

[0016]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a chain tensioner for adjusting the tension of a chain for transmitting a driving force from a crankshaft of an internal combustion engine to a camshaft via an idler shaft. In this chain tensioner, an oil supply hole is provided, a main oil passage communicating with the oil supply hole is provided, a first oil passage communicating the chain tensioner and a bearing portion of the cam shaft is provided, and the chain is provided. A second oil passage that connects the tensioner and the idler bush portion of the idler shaft is provided. Further, in a chain tensioner that adjusts the tension of a chain that transmits a driving force from a crank shaft of an internal combustion engine to a cam shaft through an idler shaft, a pressing portion that gives a tension by contacting the chain, and the pressing portion is moved forward and backward. A plunger that slides as much as possible, a ratchet that suppresses the movement of the plunger, a high pressure chamber that slides the plunger, a check ball that adjusts the pressure of the high pressure chamber, and an oil supply hole that supplies oil into the high pressure chamber. And an oil escape hole provided so as to be directed to the mounting surface so as to recirculate excess oil to the cylinder head side.

[0017]

According to the invention as described above, the oil supplied from the main oil passage to the chain tensioner through the oil supply hole portion adjusts the tension of the chain, and the bearing of the camshaft through the first oil passage. It is supplied to the idler bushing portion of the idler shaft through the second oil passage.

Further, when oil is supplied into the high pressure chamber of the chain tensioner through the oil supply hole, excess oil is discharged toward the mounting surface so as to recirculate to the cylinder head side through the oil escape hole. It

[0019]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 4 show an embodiment of the present invention. In FIG. 2, reference numeral 2 is an internal combustion engine. The internal combustion engine 2 is configured by mounting a cylinder head 6 on a cylinder block 4.

A crank bearing cap 8 is attached to the lower portion of the cylinder block 4. An oil pan (not shown) is attached to the lower portion of the crank bearing cap 8.

A crankshaft 10 is axially supported by the cylinder block 4 and the crank bearing cap 8. A crank sprocket 12, which is a drive side sprocket, is fixedly attached to the front end of the crankshaft 10.

The cylinder head 6 is provided with intake and exhaust cam shafts 14 and 16 which are spaced apart from each other on both ends of the upper portion thereof, that is, arranged in parallel so as to be axially supported. The intake and exhaust cam shafts 14 and 16 have intake and exhaust cam sprockets 1
8 and 20 are fixedly attached. Further, in the cylinder head 6, in order to form a valve operating chamber (not shown),
A cylinder head cover 22 is attached.

The intake and exhaust cam sprockets 18 and 2
An idler shaft 28 that supports a timing chain sprocket 24 and a cam chain sprocket 26 that are integrally configured is provided on the cylinder head 6 closer to the crank sprocket 12 than zero.

The crank chain sprocket 12 and the timing chain sprocket 24 have a timing chain 3
0 is wound around and provided.

The cam chain sprocket 26 and intake air,
The exhaust cam sprockets 18 and 20 have a cam chain 3
2 is wound around and provided.

Further, each of the intake and exhaust camshafts 1 from the crankshaft 10 of the internal combustion engine 2 through the idler shaft 28.
4, 16 is provided with a chain tensioner for adjusting the tension of the chain that transmits the driving force, for example, a timing chain tensioner adjuster 34 for adjusting the tension of the timing chain 30 and a cam chain tensioner adjuster 36 for adjusting the tension of the cam chain 32. .

An oil supply hole 38 is provided in the cam chain tensioner adjuster 36, and a main oil passage 40 communicating with the oil supply hole 38 is provided, and the cam chain tensioner adjuster 36 and each of the cam shafts 1 are provided.
The first oil passage 4 which connects the bearings 42 of 4 and 16
4 is provided, and a second oil passage 48 that connects the cam chain tensioner adjuster 36 and the idler bushing 46 of the idler shaft 28 is provided.

More specifically, the cam chain tensioner adjuster 36, as shown in FIGS. 1, 2 and 4, respectively, has a pressing portion 50 that comes into contact with the cam chain 32 and applies tension, and moves the pressing portion 50 forward and backward. The plunger 52 is slidably moved, a ratchet 54 for suppressing the movement of the plunger 52, a high pressure chamber 56 for sliding the plunger 52, a check ball (not shown) for adjusting the pressure of the high pressure chamber 56, and the high pressure chamber 56. An oil supply hole portion 38 for supplying oil therein and an oil escape hole portion 58 provided so as to be directed to the mounting surface F of the cam chain tensioner adjuster 36 so as to circulate excess oil to the cylinder head 6 side. There is.

As shown in FIG. 1, an oil lubrication system for the cylinder head 6 connects an oil pump (not shown) to one end of the main oil passage 40, and connects the main oil passage 40 and an intake / exhaust valve (not shown). The hydraulic lash adjuster 60 used when opening and closing the third oil passage 62
Contact us to establish.

The other end of the main oil passage 40 and the oil supply hole portion 38 of the cam chain tensioner adjuster 36.
Are connected to each other by a fourth oil passage 64, and the cam chain tensioner adjuster 36 and each of the cam shafts 1 are provided.
A fourth return oil passage 66 of the bearings 4 and 16 is provided in communication with the first oil passage 44, and the fifth oil passage 66 and the bearings 4 of the camshafts 14 and 16 are provided.
The two parts are provided so as to communicate with each other by a sixth oil passage 68.

The cam chain tensioner adjuster 36 is connected to the idler bush 46 of the idler shaft 28 by a second oil passage 48.

The idler bush 46 is provided between the integrally formed timing chain sprocket 24, cam chain sprocket 28 and the idler shaft 28.
An idler shaft bracket 70 is arranged at one end.

Next, the operation will be described.

The lubricating oil that has flowed into the main oil passage 40 is supplied to the hydraulic lash adjuster 60 through the third oil passage 62, and the cam oil is supplied from the other end of the main oil passage 40 to the fourth oil passage 64. It is supplied to the oil supply hole portion 38 of the tensioner adjuster 36.

This cam chain tensioner adjuster 36
The oil supplied to the oil supply hole portion 38 is supplied into the high pressure chamber 56 via a check ball (not shown), and the plunger 52 is slid to move to press the tip side pressing portion 50.
Is moved back and forth to contact the cam chain 32 to give a predetermined proper tension.

At this time, the excess oil is discharged by the oil escape hole 58 so as to be directed to the mounting surface F of the cam chain tensioner adjuster 36, and is circulated to the cylinder head 6 side.

The oil supplied to the cam chain tensioner adjuster 36 is supplied to the fifth returning oil passage 66 on the bearing 42 side of each of the cam shafts 14 and 16 by the first oil passage 44, and the fifth oil passage 66 is returned. From the oil passage 66 to the sixth oil passage 68, the bearing 4 of each cam shaft 14, 16
It is supplied to two parts.

Further, the oil supplied to the cam chain tensioner adjuster 36 is supplied to the idler bushing 46 of the idler shaft 28 by the second oil passage 48.

As a result, each hydraulic lash adjuster 6
0, the cam chain tensioner adjuster 36, the idler bush 46, and the bearing 42 of each of the camshafts 14 and 16 when supplying oil to the main oil passage 4
The cylinder head 6 which is configured in parallel with 0
The oil lubrication system is partially in series, that is, from the cam chain tensioner adjuster 36 to the idler bush 46.
Also, oil can be supplied to the bearings 42 of the camshafts 14 and 16, and the oil escape hole 60, which has been an open end in the past, can be circulated to the cylinder head 6 side. The hydraulic pressure of the adjuster 60 can be easily ensured, and the performance of other auxiliary machines can be maintained in a good state, which is practically advantageous.

Further, by circulating the wasted oil, which was conventionally wasted from the open end, to the cylinder head 6 side, it is possible to eliminate the wasted oil for lubrication, which contributes to downsizing of the oil pump. In addition, it is economically advantageous.

Further, in the prior art, in order to adjust the hydraulic pressure, the throttle was provided immediately before the bearing portion of the cam shaft or immediately before the idler bush portion of the idler shaft, but in the present embodiment, the throttle is provided. It is possible to achieve reduction of the number of parts and reduction of processing cost without the need to provide the.

[0043]

As described in detail above, according to the present invention, an oil supply hole is provided in a chain tensioner for adjusting the tension of a chain for transmitting a driving force from a crankshaft of an internal combustion engine to a camshaft via an idler shaft. A main oil passage communicating with the oil supply hole is provided, a first oil passage communicating with the chain tensioner and the bearing portion of the cam shaft is provided, and a second oil communicating with the idler bush portion of the idler shaft is provided. Since the passage is provided, in the oil lubrication system of the cylinder head of the internal combustion engine, the oil escape hole, which was conventionally an open end, can be circulated to the cylinder head side, and the open end can be reduced to reduce the hydraulic lash adjuster. The oil pressure can be easily secured, which is practically advantageous. Also, by circulating the oil that was wasted by discharging it from the open end in the past to the cylinder head side, it is possible to reduce the waste of oil for lubrication, which can contribute to the downsizing of the oil pump, which is economical. It is also advantageous. Further, in the prior art, in order to adjust the hydraulic pressure, the throttle was provided immediately before the bearing portion of the cam shaft or immediately before the idler bush portion of the idler shaft, but it is not necessary to provide the throttle, and the number of parts can be reduced. It is possible to reduce the cost and the processing cost.

Further, in the chain tensioner for adjusting the tension of the chain that transmits the driving force from the crankshaft of the internal combustion engine to the camshaft via the idler shaft, the pressing portion that gives tension by contacting the chain and the pressing portion is moved forward and backward. A plunger that slides to operate, a ratchet that suppresses the movement of the plunger, a high pressure chamber that slides the plunger, a check ball that adjusts the pressure in the high pressure chamber, and an oil supply hole that supplies oil to the high pressure chamber. Since there is an oil escape hole that is provided by directing the excess oil to the mounting surface so as to recirculate the excess oil to the cylinder head side, it is possible to recirculate the oil escape hole that was conventionally an open end to the cylinder head side. The open end can be reduced and the hydraulic pressure of the hydraulic lash adjuster can be easily secured, which is practically advantageous. The oil that has been wasted by discharge from the open end to cause circulate to the cylinder head side, it is possible to avoid waste of lubricant oil, which can contribute to miniaturization of the oil pump. Further, in order to adjust the hydraulic pressure, it is not necessary to provide a throttle immediately before the bearing portion of the cam shaft or immediately before the idler bush portion of the idler shaft, and the number of parts and the processing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram of an oil lubrication system of a cylinder head showing an embodiment of the present invention.

FIG. 2 is a schematic front view of an internal combustion engine.

FIG. 3 is a schematic right side view of the internal combustion engine.

FIG. 4 is a bottom view of the Kamchi tensioner adjuster.

FIG. 5 is a bottom view of a cam chain tensioner adjuster showing a conventional technique of the present invention.

FIG. 6 is a front view of a cam chain tensioner adjuster.

FIG. 7 is a right side view of the Kamchi tensioner adjuster.

FIG. 8 is a lubrication system diagram of oil in a cylinder head.

[Explanation of symbols]

 2 Internal combustion engine 4 Cylinder block 6 Cylinder head 10 Crankshaft 12 Crank sprocket 14 Intake camshaft 16 Exhaust camshaft 18 Intake cam sprocket 20 Exhaust cam sprocket 24 Timing chain sprocket 26 Cam chain sprocket 28 Idler shaft 30 Timing chain 32 Cam chain 36 Cam chain Tensioner adjuster 38 Oil supply hole 40 Main oil passage 42 Bearing 44 First oil passage 48 Second oil passage 50 Pressing portion 52 Plunger 54 Ratchet 56 High pressure chamber 58 Oil escape hole 60 Hydraulic lash adjuster 62 Third oil passage 64 Fourth Oil passage 66 5th oil passage 68 68th oil passage

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 28, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Figure 4]

[Fig. 2]

[Figure 3]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

Claims (2)

[Claims] 1. A chain tensioner for adjusting the tension of a chain for transmitting a driving force from a crank shaft of an internal combustion engine to a cam shaft via an idler shaft, wherein the chain tensioner is provided with an oil supply hole portion, and the oil supply hole portion is provided. Is provided with a main oil passage communicating with the chain tensioner and a first oil passage communicating with the bearing portion of the camshaft, and a second oil passage communicating with the idler bush portion of the idler shaft. A chain tensioner characterized by being provided. 2. In a chain tensioner for adjusting the tension of a chain for transmitting a driving force from a crankshaft of an internal combustion engine to a camshaft via an idler shaft, a pressing portion that gives tension by contacting the chain and a pressing portion A plunger that slides to move forward and backward, a ratchet that suppresses the movement of the plunger, a high-pressure chamber that slides the plunger, a check ball that adjusts the pressure of the high-pressure chamber, and an oil that supplies oil to the high-pressure chamber. A chain tensioner having a supply hole and an oil escape hole provided so as to be directed to a mounting surface so as to circulate excess oil to the cylinder head side.