JPH0932572A - Hydraulic tensioner of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an effective capacity of an operating fluid storage chamber, and prevent a delay in supply of an operating fluid to a tensioner at restarting time by lowering an oil level of the operating fluid necessary at restarting time more than an operating fluid supply hole by a partition wall extended downward from an upper side wall surface in the operating fluid storage chamber of a cylinder block. SOLUTION: An operating fluid delivered to an operating fluid storage chamber 38 from an operating fluid delivery hole of a cylinder block 4 flows on the upper side of a partition wall 66, and flows toward an operating fluid supply hole 58 on the under side of the partition wall 66 by bypassing the tip 72. In a hydraulic tensioner, the operating fluid of the operating fluid storage chamber 38 push-advances a plunger by oil pressure of a high pressure chamber supplied from the operating fluid supply hole 58 and force of a spring, and proper tensile force is applied to a timing chain through a swinging body. Since a partition wall 66 in the operating fluid storage chamber 38 lowers an oil level L2 at restarting time more than the operating fluid supply hole 58, an effective quantity of the operating fluid storage chamber 38 can be secured large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic tensioner for an internal combustion engine, and more particularly, it can increase the effective capacity of a hydraulic oil reservoir of a cylinder head with respect to a hydraulic oil supply hole of the hydraulic tensioner so that the hydraulic tensioner can be restarted. The present invention relates to a hydraulic tensioner for an internal combustion engine that can prevent a delay in the supply of hydraulic fluid to the hydraulic tensioner, can prevent malfunction of the hydraulic tensioner at the time of restarting, and can simplify the layout.

[0002]

2. Description of the Related Art In an internal combustion engine, the rotation of a crankshaft is transmitted to a camshaft by a chain to open / close an intake / exhaust valve at a predetermined timing. The chain is provided with a hydraulic tensioner in order to prevent tooth skipping and noise due to stretching.

A conventional hydraulic tensioner for an internal combustion engine is shown in FIG. In the figure, 102 is a cylinder block of an internal combustion engine (not shown), and 104 is a hydraulic tensioner. The hydraulic tensioner 104 applies appropriate tension by hydraulic pressure to a timing chain that is wound around a crank shaft (not shown) that is axially supported by the cylinder block 102.

The cylinder block 102 is shown in FIG.
As shown in FIG. 13, a block-side mating surface 106 to which the hydraulic tensioner 104 is attached is formed and provided.
The block-side mating surface 106 is provided with a hydraulic oil storage chamber 108 formed by recessing the hydraulic oil storage chamber 108.
A hydraulic oil discharge hole 110 for discharging hydraulic oil is formed above and the block side screw hole 112 is formed.

The hydraulic tensioner 104 has a main body 114.
Attach the plunger 116 to the
A pusher 118 is attached to 16. Hydraulic tensioner 1
On 04, a tensioner-side mating surface 120 that contacts the block-side mating surface 106 is formed. A hydraulic oil supply hole 122 is formed in the tensioner-side mating surface 120, and a tensioner-side mounting hole 124 that matches the block-side screw hole 112 is formed.

As shown in FIG. 11, the hydraulic oil supply hole 122 is provided in the cylinder block 102 of the hydraulic tensioner 104.
Is attached to the working oil reservoir chamber 108 below the working oil discharge hole 110 to guide the working oil in the working oil reservoir chamber 108 to the high pressure chamber 126. The high-pressure chamber 126 generates a high-pressure hydraulic pressure that pushes the plunger 116 outward of the main body 114 by a check valve (not shown).

In the hydraulic tensioner 104, the block-side mating surface 106 of the cylinder block 102 is brought into contact with the tensioner-side mating surface 120, and the mounting bolt 128 is inserted into the tensioner-side mounting hole 124 so that the block-side screw hole 11 is formed.
It is attached to the cylinder block 102 by being screwed on the No. 2.

The hydraulic tensioner 104 has a hydraulic oil discharge hole 1
The working oil discharged from 10 and stored in the working oil reservoir chamber 108 is supplied to the high pressure chamber 126 through the working oil supply hole 122,
High pressure chamber 1 whose pressure is increased by a check valve (not shown)
The plunger 116 is pushed outward of the main body 114 by the hydraulic pressure of 26 and the elastic force of a spring (not shown), and
An oscillating body (not shown) is pushed by 18 to apply proper tension to the timing chain.

As a hydraulic tensioner for such an internal combustion engine, Japanese Utility Model Laid-Open No. 6-45141 and Japanese Utility Model Laid-Open No. 3-857 are disclosed.
There is one disclosed in Japanese Patent No. 40.

In the hydraulic tensioner disclosed in Japanese Utility Model Laid-Open No. 6-45141, the housing of the tensioner is divided into a high pressure chamber and a low pressure chamber by a plunger, and splash oil is collected in a housing above the low pressure chamber to collect the splash oil. Is provided with an oil reservoir for supplying a high pressure chamber and a low pressure chamber with a first oil passage that creates a flow resistance, and a second oil passage that obtains a free flow between the high pressure chamber and the low pressure chamber. A check valve is provided in the second oil passage.

According to the method disclosed in Japanese Utility Model Laid-Open No. 3-85740, a reservoir chamber and a pressure chamber are formed in series in a plunger installed in a plunger chamber of a tensioner housing so as to be able to move back and forth. Forming a first oil passage in the tensioner housing and the plunger,
A check valve is provided in the second oil passage that connects the reservoir chamber and the pressure chamber, and a spring that biases the pressure chamber to retract the plunger is provided.

[0012]

By the way, the conventional hydraulic tensioner 104 is supplied with hydraulic oil from the hydraulic oil storage chamber 108 of the cylinder block 102 to apply tension to the timing chain. The hydraulic oil reservoir chamber 108 is provided to prevent air from being removed from the hydraulic oil and to prevent a delay in supplying the hydraulic oil to the hydraulic tensioner 104 when the internal combustion engine is restarted after being stopped.

However, the conventional hydraulic tensioner 104
Despite the large volume of the hydraulic oil reservoir 108,
Since the vertical separation distance between the hydraulic oil discharge hole 110 and the hydraulic oil supply hole 122 is small, the difference between the oil level L1 immediately after the internal combustion engine is stopped as shown in FIG. 12 and the oil level L2 at the restart as shown in FIG. Has a disadvantage that the effective capacity between the oil surfaces L1 and L2 is reduced. Therefore, the conventional hydraulic tensioner 104 has a disadvantage that it causes a delay in the supply of hydraulic oil when the internal combustion engine is restarted, resulting in a malfunction.

[0014]

Therefore, according to the present invention, in order to eliminate the above-mentioned inconvenience, tension is hydraulically applied to a timing chain wound around a crankshaft which is axially supported by a cylinder block of an internal combustion engine. In a hydraulic tensioner for an internal combustion engine, a block side mating surface on which the hydraulic tensioner is mounted is formed on the cylinder block, and the block side mating surface is recessed to form a working oil reservoir chamber. A hydraulic oil discharge hole for discharging hydraulic oil is formed above the chamber, and a tensioner-side mating surface that abuts against the block-side mating surface is formed on the hydraulic tensioner. The hydraulic oil discharge hole is provided to communicate with the hydraulic oil reservoir below the hydraulic oil discharge hole to guide the hydraulic oil to the high pressure chamber. Characterized by providing form a partition wall which is extended downwardly from the upper wall of said hydraulic oil reservoir chamber between the hole and the working oil supply hole.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A hydraulic tensioner according to the present invention is a partition extending downward from an upper wall surface of a hydraulic oil reservoir formed between a hydraulic oil discharge hole of a cylinder block and a hydraulic oil supply hole of a hydraulic tensioner. The wall allows the oil level of the hydraulic oil required at restart to be lower than the hydraulic oil supply hole, and the difference between the oil level immediately after the internal combustion engine has stopped and the oil level at restart can be increased. , The effective capacity can be increased.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 9 show an embodiment of the present invention. In FIG. 9, 2 is an internal combustion engine, 4 is a cylinder block, 6 is a cylinder head, 8 is a crank shaft, 10 is an intake cam shaft, 12 is an exhaust cam shaft, and 14 is an intermediate shaft.

In the internal combustion engine 2, a crank sprocket 16 is attached to a crank shaft 8 which is rotatably supported by a cylinder block 4, an intermediate sprocket 18 and a cam shaft sprocket 20 are rotatably supported on an intermediate shaft 14, and an intake sprocket 22 is attached to an intake cam 10. The exhaust sprocket 24 is attached to the exhaust cam shaft 12.

A timing chain 26 is wound around the crank sprocket 16 and the intermediate sprocket 18, as shown in FIGS. A cam chain 28 is wound around the cam shaft sprocket 20, the intake sprocket 22, and the exhaust sprocket 24 that are integrally formed with the intermediate sprocket 18.

The timing chain 26 is provided with a chain guide 30 on the tension side and a hydraulic tensioner 32 on the loose side. A chain tensioner 34 is provided on the cam chain 28.

The cylinder block 4 is shown in FIGS.
As shown in FIG. 5, a block side mating surface 36 to which the hydraulic tensioner 32 is attached is formed and provided. The block side mating surface 36 is provided with a working oil reservoir chamber 38 formed by being depressed, and a working oil discharge hole 40 for discharging working oil is formed above the working oil reservoir chamber 38, and is provided on the block side. The screw hole 42 is formed and provided.

In the hydraulic tensioner 32, as shown in FIGS. 1 and 2, a plunger 46 is removably mounted on a main body 44, and a pusher 48 is mounted on the plunger 46. As shown in FIG. 9, the pushing body 48 is brought into contact with the contact body 52 of the rocking body 50 arranged along the timing chain 26. The rocking body 50 is pivotally supported on the cylinder block 4 by a rocking bolt 54 on one end side so that the other end side can rock.

The main body 44 of the hydraulic tensioner 32 has a tensioner-side mating surface 56 that abuts against the block-side mating surface 36. In the main body 44, a hydraulic oil supply hole 58 is formed in the tensioner-side mating surface 56, and a tensioner-side mounting hole 60 that matches the block-side screw hole 42 is formed.

As shown in FIG. 2, the hydraulic oil supply hole 58 is connected to the hydraulic oil reservoir chamber 38 below the hydraulic oil discharge hole 40 by mounting the hydraulic tensioner 32 on the cylinder block 4, and the hydraulic oil reservoir 58 is connected to the hydraulic oil reservoir 38. The hydraulic oil in the chamber 38 is supplied to the high pressure chamber 62.
Lead to. The high-pressure chamber 62 generates a high-pressure hydraulic pressure that pushes the plunger 46 outward of the main body 44 by a check valve (not shown).

The hydraulic oil reservoir 38 of the cylinder block 4
As shown in FIGS. 3 and 4, the inside of the working oil discharge hole 40 and the working oil supply hole 58 face downward from the upper wall surface 64 located between the working oil discharge hole 40 and the working oil supply hole 58. A partition wall 66 extending so as to partition the space is formed and provided.

The partition wall 66 is extended to the vicinity thereof without reaching the lower side wall surface 68 in the hydraulic oil reservoir chamber 38 so as to secure the communication between the hydraulic oil discharge hole 40 and the hydraulic oil supply hole 58. Has been formed. As shown in FIG. 2, the partition wall 66 is provided such that one side in the extended width direction is continuously provided to the bottom side wall surface 70 of the hydraulic oil reservoir chamber 38, and the other side in the extended width direction is a block side mating surface. It is provided in accordance with 36.

As a result, the partition wall 66 is formed so as to cover the hydraulic oil supply hole 60 with respect to the hydraulic oil discharge hole 40, and the tip 72 is located below the hydraulic oil supply hole 58. Therefore, the hydraulic oil discharge hole 40 and the hydraulic oil supply hole 58
Is the tip 7 of the partition wall 66 in the hydraulic oil reservoir chamber 38.
2, the hydraulic oil flows so as to bypass the tip 72 of the partition wall 66, as shown by an arrow A in FIG.

Next, the operation will be described.

In the hydraulic tensioner 32, the block side mating surface 36 of the cylinder block 4 is brought into contact with the tensioner side mating surface 56, and the mounting bolt 74 is inserted into the tensioner side mounting hole 60 and screwed into the block side screw hole 42. By doing so, it is attached to the cylinder block 4.

The hydraulic oil discharged from the hydraulic oil discharge hole 40 of the cylinder block 4 into the hydraulic oil reservoir chamber 38 is indicated by an arrow A in FIG.
As shown by, the flow flows from the hydraulic oil discharge hole 40 side to the upper side of the partition wall 66, bypasses the tip 72, and flows to the lower side of the partition wall 66 toward the hydraulic oil supply hole 58.

The hydraulic tensioner 32 supplies the hydraulic oil in the hydraulic oil reservoir chamber 38 to the high pressure chamber 62 through the hydraulic oil supply hole 58,
The plunger 46 is pushed outward of the main body 44 by the hydraulic pressure of the high pressure chamber 62 increased by the check valve (not shown) and the elastic force of the spring (not shown), and the oscillating body 50 is pushed by the pushing body 48 via the contact body 52. Is pushed to apply proper tension to the timing chain 26.

As shown in FIGS. 3 and 4, the inside of the hydraulic oil reservoir chamber 38 of the cylinder block 4 faces downward from the upper wall surface 64 located between the hydraulic oil discharge hole 40 and the hydraulic oil supply hole 58. A partition wall 66 is formed so as to extend so as to partition between the hydraulic oil discharge hole 40 and the hydraulic oil supply hole 58. As shown in FIG. 4, the partition wall 66 can lower the oil level L2 at the time of restart than the hydraulic oil supply hole 58.

As a result, the hydraulic oil reservoir chamber 38 has a distance more than the vertical separation between the hydraulic oil discharge hole 40 and the hydraulic oil supply hole 58,
The difference in height between the oil level L1 immediately after the internal combustion engine 2 shown in FIG. 3 is stopped and the oil level L2 at the restart shown in FIG. 4 becomes large, and the effective capacity between the oil levels L1 and L2 becomes large.

Therefore, the hydraulic tensioner 32 can secure a larger effective volume of the hydraulic oil reservoir chamber 38 of the cylinder head 4 with respect to the hydraulic oil supply hole 58, so that the hydraulic tensioner 32 operates when restarted. The oil supply delay can be prevented, and the hydraulic oil supply delay prevention prevents the hydraulic tensioner 32 from malfunctioning at restart.

Further, since the hydraulic tensioner 32 is provided with only the partition wall 66 in the hydraulic oil reservoir chamber 38, the layout can be simplified.

[0035]

As described above, according to the present invention, in the hydraulic tensioner, the partition wall extending downward from the upper wall surface in the hydraulic oil sump chamber causes the hydraulic oil surface of the hydraulic oil required at the time of restart to be increased. It can be made lower than the supply hole, the difference between the oil level immediately after the internal combustion engine is stopped and the oil level required for restarting can be increased, and the effective capacity can be increased.

Therefore, this hydraulic tensioner can increase the effective capacity of the working oil reservoir of the cylinder head with respect to the working oil supply hole, thereby preventing a delay in the supply of the working oil to the hydraulic tensioner at the time of restart. It is possible to prevent malfunction of the hydraulic tensioner at the time of restart. Further, this hydraulic tensioner can be laid out simply because the partition wall is only provided in the hydraulic oil reservoir chamber.

[Brief description of drawings]

FIG. 1 is a front view of a hydraulic tensioner showing an embodiment of the present invention.

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

FIG. 3 is a front view of a portion of a hydraulic oil reservoir chamber of a cylinder block immediately after the internal combustion engine is stopped.

FIG. 4 is a front view of a portion of a hydraulic oil reservoir chamber of a cylinder block when the internal combustion engine is restarted.

FIG. 5 is a front view of a cylinder block.

6 is an enlarged front view taken along the arrow 〓 of FIG.

FIG. 7 is a vertical cross-sectional view of the hydraulic tensioner portion of FIG.

8 is a vertical cross-sectional view of the intermediate shaft portion of FIG.

FIG. 9 is a front view of an internal combustion engine.

FIG. 10 is a front view of a hydraulic tensioner showing a conventional example.

11 is a sectional view taken along line XI-XI of FIG.

FIG. 12 is a front view of a portion of the hydraulic oil reservoir chamber of the cylinder block immediately after the internal combustion engine is stopped.

FIG. 13 is a front view of a portion of a hydraulic oil reservoir chamber of a cylinder block when the internal combustion engine is restarted.

[Explanation of symbols]

 2 Internal combustion engine 4 Cylinder block 26 Timing chain 32 Hydraulic tensioner 36 Block side mating surface 38 Hydraulic oil reservoir 40 Hydraulic oil discharge hole 44 Main body 46 Plunger 48 Pusher 56 Tensioner mating surface 58 Hydraulic oil supply hole 62 High pressure chamber 64 Upper side Wall surface 66 Partition wall 68 Lower side wall surface 70 Bottom side wall surface 72 Tip

Claims (1)

[Claims] 1. A hydraulic tensioner for an internal combustion engine, which applies tension to a timing chain wound around a crankshaft axially supported by a cylinder block of the internal combustion engine by hydraulic pressure, in which the hydraulic tensioner is attached to the cylinder block. A mating surface is formed, and the block-side mating surface is recessed to form a hydraulic oil reservoir chamber, and a hydraulic oil discharge hole for discharging hydraulic oil is formed above the hydraulic oil reservoir chamber. The hydraulic tensioner is provided with a tensioner-side mating surface that comes into contact with the block-side mating surface. The tensioner-side mating surface communicates with the hydraulic oil reservoir below the hydraulic oil discharge hole. Is provided by forming a hydraulic oil supply hole for guiding the hydraulic fluid to the high pressure chamber, and is provided between the hydraulic oil discharge hole and the hydraulic oil supply hole downward from the upper wall surface of the hydraulic oil reservoir chamber. A hydraulic tensioner for an internal combustion engine, characterized in that a partition wall extending in the opposite direction is formed and provided.