JPH0914363A - Chain adjuster - Google Patents

Abstract

PURPOSE: To reduce noise and to lengthen longevity of a chain by providing a plunger to slide in a body formed in a bottomed cylindrical shape, a spring to energize the plunger in the projecting-direction in the body and a damper formed of a member free to adjust resiliency. CONSTITUTION: A plunger 40 of a chain adjuster 30 is projected by resiliency consisting of energizing force of a spring 42 and elasticity restoring force of a primary damper 46. Consequently, a head end of the plunger 40 pushes a pad, draws in a tensioner through a tension arm, presses the tensioner on a chain and gives proper tensile force to the chain. Additionally, when the plunger 40 retreats against the energizing force of the spring 42 and the resiliency of the primary damper 46 and the plunger 40 makes contact with a plate 50, the resiliency becomes large by a secondary damper 48 arranged on the side of a bottom part of a body 38 and advancing force of the plunger 40 becomes larger. Accordingly, it is possible to certainly reduce noise from the chain.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chain adjuster, and in particular, a chain adjuster is provided with a spring arranged to bias a plunger in a projecting direction and a damper formed by a member capable of adjusting repulsive force, The present invention relates to a chain adjuster that does not use.

[0002]

2. Description of the Related Art An engine has a crankshaft that converts a reciprocating motion of a piston into a rotary motion. The driving force, which is a rotational force from the crankshaft, is transmitted to, for example, a camshaft, and the camshaft converts the rotational operation into an opening / closing operation of an intake / exhaust valve.

At this time, a chain is wound around the crank sprocket mounted on the crankshaft and the first and second cam sprockets mounted on the two first and second camshafts, respectively, and the It is used as a driving force transmission path.

Further, a tensioner is arranged near the chain, and the tensioner is pressed against the chain by an adjuster to give proper tension to the chain.

The chain adjuster is disclosed in Japanese Utility Model Laid-Open No. 60-95253. The chain tensioner disclosed in this publication has a rod-like plunger slidably fitted on a guide body, and a ratchet biased in the forward direction of the plunger in a notch portion engraved on the axial side surface of the plunger. A chain tensioner that applies tension to the transmission chain by constantly applying an urging force in the forward direction to the plunger by engaging the members, and is interposed between the surfaces where the guide body and the plunger face each other. A rubber-like elastic body is attached to one of the contact surfaces so that the sheet floats with respect to the guide body.

[0006]

By the way, in a conventional chain adjuster, that is, a type of chain adjuster that uses both spring urging force and hydraulic pressure, as shown in FIG. 6, the chain adjuster 130 has a tubular body 138. And a plunger 140 that slides inside the body 138.

A reserve chamber 180 is formed at the bottom of the body 138, and a hydraulic pressure supply hole 182 for connecting the reserve chamber 180 to a hydraulic pressure supply means (not shown) is provided, and the reserve chamber 180 and the plunger 140 side are connected to each other. A communication hole 184 for communication is provided.

The connecting hole portion 184 and the plunger 1
A check ball 186 is provided on the 40 side, a retainer 188 for holding the check ball 186 is provided, and a spring 142 is provided in the retainer 188 and the body 138 to urge the plunger 140 in the protruding direction. A high-pressure chamber 190 is formed at a portion where the spring 142 is provided.

A notch 192 is formed on the outer peripheral portion of the plunger 140, and the notch 192 is formed.
A ratchet 194, which is engaged with, and prevents the movement of the plunger 140, is disposed on the body 138.

If the chain has a tension, the plunger 140 is moved forward by the urging force of the spring 142 and the volume of the high pressure chamber 190 increases. Oil is immediately supplied from the reserve chamber 180 to the increased volume.

At this time, the plunger 140 can move only the amount of backlash in the backward direction by the action of the ratchet 194.

When the engine is stopped, the plunger 14 of the chain adjuster 130 is changed depending on the position of the camshaft.
Although a force to retract 0 works, it prevents the plunger 140 from retracting. In other words, it is possible to prevent the tooth jumping of the chain and the rumble noise of the chain at the time of restart.

However, a ratchet is usually used for the conventional chain adjuster of the type that uses both spring force and hydraulic pressure. The ratchet, which works when the chain is extended, prevents the plunger from retracting. When the ratchet moves one notch in the direction in which the chain is stretched, the tension may become stronger due to the temperature of the engine and the like. In other words, the movement is blocked by the ratchet claws even when trying to move backward.

As a result, the tension state of the chain becomes overtension, the noise generated from the chain becomes large, the useful life of the chain is shortened, and it is economically disadvantageous.

When the ratchet is removed as a measure against noise, when air is mixed in the high pressure chamber, the chain becomes too loose and the chain violent noise occurs, which causes noise and the plunger bottoms out against the body. There is the inconvenience that sound may be produced.

Further, there is a conventional chain adjuster as shown in FIG. The chain adjuster 230 disclosed in FIG. 7 has a structure in which a cylindrical ball seat 296 is arranged on a check ball 286 and oil passes through the ball seat 296.

Similar to the chain adjuster 130 described with reference to FIG. 6, the chain adjuster 230 is a type of chain adjuster that uses both spring force and hydraulic pressure, and is the same as the chain adjuster 130 described with reference to FIG. However, the description of the inconvenience is omitted here.

[0018]

Therefore, according to the present invention, in order to eliminate the above-mentioned inconvenience, a crank sprocket mounted on a crankshaft of an engine and first and second crankshafts respectively mounted on a first camshaft and a second camshaft. 2 A chain adjuster that winds a cam sprocket and applies a tensioner to this chain to apply proper tension to the chain is used. It is characterized in that it has a sliding plunger, a spring arranged to urge the plunger in the protruding direction in the body, and a damper formed of a member capable of adjusting repulsive force.

[0019]

According to the invention as described above, when the plunger of the chain adjuster projects due to the urging force of the spring and the repulsive force of the damper, the plunger presses the tensioner against the chain to give proper tension to the chain,
By not using hydraulic pressure, it is not necessary to secure an oil passage, and it is not necessary to machine oil holes in the cylinder block and cylinder head, which reduces the machining process and cost.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 3 show a first embodiment of the present invention. In FIG. 3, 2 is a 4-cycle engine mounted on an automobile (not shown), 4 is a cylinder head,
6 is a cylinder block, and 8 is a lower case.

The engine 2 includes a cylinder head 4 and
It has a cylinder block 6 mounted on the lower surface of the cylinder head 4 and a lower case 8 mounted on the lower surface of the cylinder block 6.

A crankshaft 10 is axially supported by the lower surface of the cylinder block 6 and the lower case 8, and two first and second camshafts 12, 14 are axially supported by the upper surface of the cylinder head 4. .

A crank sprocket 16 is attached to one end of the crankshaft 10, that is, a front surface side which is one side of the engine 2, and the first and second camshafts 12 and 14 are provided with first and first crankshafts, respectively. Two cam sprockets 18 and 20 are mounted respectively, and a timing chain 22 is wound around the crank sprocket 16 and the first and second cam sprockets 18 and 20.

Further, the tension side of the chain 22, that is, FIG.
, The first guide portion 24 is arranged near the outside of the chain 22 on the right side, and the second guide portion 26 is arranged between the first and second cam sprockets 18 and 20 and near the outside of the chain 22. A tensioner 28 is disposed on the loose side of 22, that is, in the vicinity of the outside of the chain 22 on the left side in FIG. 2, and the tensioner 28 is attached to the cylinder block 6 so as to be swingable about its lower end.

Between the tension side and the loose side of the chain 22,
That is, the chain adjuster 30 is provided inside the chain 22, and the tensioner arm 32 that connects the chain adjuster 30 and the tensioner 28 is provided. When the chain adjuster 30 is provided inside the chain 22, the chain adjuster 30 is provided. 30 later described plunger 4
The load direction, which is the pushing direction of 0, is arranged so as to be directed to the right side in FIG.

Then, one end side of the tensioner arm 32 is fixed to the tensioner 28 by a fixing bolt 34 from the surface side which is one side of the engine 2. At this time, the other end of the tensioner arm 32 is attached to the chain adjuster 30 via the pad 36.

Further, the chain adjuster 30 is provided with a body 38 formed in a cylindrical shape with a bottom, a plunger 40 sliding in the body 38, and a plunger 40 arranged in the body 38 so as to urge the plunger 40 in a protruding direction. Installed spring 42
And a damper 44 formed of a member capable of adjusting the repulsive force.

More specifically, the chain adjuster 30
The damper 44 is composed of two primary and secondary dampers 46 and 48 having different repulsive forces so that the repulsive force characteristics can be changed.

Then, the chain adjuster 30 is
As shown in FIG. 1, a body 38 formed in a cylindrical shape with a bottom, a plunger 40 sliding in the body 38, a spring 42 arranged in the plunger 40, and a spring 4
2 and a secondary damper 4 disposed on the bottom side of the body 38 and in contact with the spring 42 and the primary damper 46 via a plate 50.
It is composed of 8 and.

The primary and secondary dampers 46 and 48 are made of a member such as resin or rubber capable of adjusting the repulsive force, and the hardness of the secondary damper 48 is set to be large with respect to the primary damper 46. .

Reference numeral 52 is a cylinder head cover of the engine 2.

Next, the operation will be described.

When the plunger 40 of the chain adjuster 30 projects rightward in FIG. 3 by the urging force of the spring 42 and the repulsive force of the elastic restoring force of the primary damper 44, the tip of the plunger 40 pushes the pad 36,
The tensioner 28 is pulled in via the tensioner arm 32, and the tensioner 28 is pressed against the chain 22 to give proper tension to the chain 22.

When the plunger 40 retracts against the urging force of the spring 42 and the repulsive force of the primary damper 44, and the plunger 40 contacts the plate 50,
The repulsive force of the secondary damper 48 arranged on the bottom side of the body 38 acts, and as shown in FIG. 2, the repulsive force is increased by the secondary damper 48 having high hardness, and the forward force of the plunger 40 is increased. Is even larger.

As a result, when the plunger 40 of the chain adjuster 30 is operated, it is not necessary to secure an oil passage by not using hydraulic pressure, and it is not necessary to machine an oil hole in the cylinder block 6 or the cylinder head 4. The process and processing cost can be reduced, which is advantageous in practical and economical aspects.

Further, since the hydraulic pressure is not required for the operation of the plunger 40 of the chain adjuster 30, the oil pump performance can be lowered as compared with the conventional one.
It is possible to reduce mechanical loss and save fuel.

Further, since troubles such as clogging of oil holes can be prevented in advance, usability can be improved.

Furthermore, since the ratchet as in the prior art is unnecessary, the number of parts can be reduced, the cost can be reduced, and it is economically advantageous.

If the damper 44 is replaced, the repulsive force can be easily adjusted, which can contribute to the reduction of man-hours during engine development.

Further, since the operating range of the plunger 40 can be widened and the operating characteristics are changed, the noise from the chain 22 can be surely reduced.

FIG. 4 shows a second embodiment of the present invention. In the second embodiment, portions that perform the same functions as those in the first embodiment will be described with the same reference numerals.

The feature of the second embodiment is that the damper 60 of the chain adjuster 30 is formed by primary and secondary dampers 62 and 64 having different repulsive forces, and at least the primary and / or secondary dampers. The point is that it has a laminated structure composed of two damper members.

That is, the damper 60 of the chain adjuster 30 is connected to the primary and secondary dampers 62, 62 having different repulsive forces.
When forming by 64, for example, the primary and secondary dampers 6
2 and 64 are respectively two damper members 62-1 and 62-2,
It is formed in a laminated structure composed of 64-1 and 64-2.

Further, the primary and secondary dampers 62, 64
Is formed of a member such as resin or rubber capable of adjusting repulsive force, and damper members 62-1 and 62-2 forming the primary damper 62 and damper members 64-1 and 64 forming the secondary damper 64. The hardness of the secondary damper 64 is set higher than that of the primary damper 62 by changing the hardness of -2 respectively.

By the way, when the plunger 40 of the chain adjuster 30 is operated, it is not necessary to secure the oil passage by not using the hydraulic pressure as in the case of the first embodiment, and the cylinder block and the cylinder head are not required. Since the oil hole machining is unnecessary, the machining process and machining cost can be reduced, which is practically and economically advantageous.

Also, since the hydraulic pressure is not required for the operation of the plunger 40 of the chain adjuster 30, the oil pump performance can be reduced as compared with the conventional one, as in the first embodiment. It is possible to reduce mechanical loss and save fuel.

Furthermore, since troubles such as clogging of oil holes can be prevented, the usability can be improved as in the case of the first embodiment.

Furthermore, by eliminating the need for a ratchet as in the prior art, the number of parts can be reduced and the cost can be reduced, as in the first embodiment.

Further, the damper 60 of the chain adjuster 30 is provided with primary and secondary dampers 62 and 64 having different repulsive forces.
When formed by, the primary and secondary dampers 62, 64 are respectively provided with two damper members 62-1, 62-2, 64-1, 6
By forming the laminated structure of 4-2, it becomes easy to adjust the repulsive force, which can contribute to reduction of man-hours during engine development.

Further, as in the case of the first embodiment described above, the operating range of the plunger 40 can be widened and the operating characteristics are also changed, so that noise from the chain can be reliably reduced. It is a thing.

FIG. 5 shows a third embodiment of the present invention.

The feature of the third embodiment is that the chain adjuster 30 is provided with a unique damper 70.

That is, the chain adjuster 30
As shown in FIG. 5, the body 38 is formed in a bottomed cylindrical shape.
A plunger 40 sliding in the body 38, a spring 42 arranged in the plunger 40, and a damper 70 arranged on the bottom side of the body 38 and contacting the spring 42 via a plate 50. The configuration consists of and.

By the way, when the plunger 40 of the chain adjuster 30 is operated, it is not necessary to secure the oil passage by not using the hydraulic pressure as in the first and second embodiments, and the cylinder block is not required. It is not necessary to machine oil holes in the cylinder head or cylinder head, and the machining process and machining cost can be reduced, which is practically and economically advantageous.

Further, since the hydraulic pressure is not required for the operation of the plunger 40 of the chain adjuster 30, the oil pump performance is lowered as compared with the conventional ones, as in the first and second embodiments. It is possible to reduce mechanical loss and save fuel consumption.

Furthermore, since troubles such as clogging of oil holes can be prevented in advance, the usability can be improved as in the first and second embodiments.

Furthermore, by eliminating the need for a ratchet as in the prior art, the number of parts can be reduced and the cost can be reduced as in the first and second embodiments.

Further, since the chain adjuster 30 is provided with the only damper 70, the structure can be simplified, and the repulsive force can be easily adjusted by replacing the damper 70, thereby reducing the number of man-hours during engine development. Can contribute to.

Further, similar to the first and second embodiments, the operating range of the plunger 40 can be widened and the operating characteristics are also changed, so that noise from the chain can be reliably ensured. It can be reduced.

The present invention is not limited to the above-mentioned first to third embodiments, but various application modifications are possible.

For example, although the chain adjuster has been described in the embodiment of the present invention, it can be applied to a belt adjuster.

[0063]

As described above in detail, according to the present invention, the crank sprocket mounted on the crankshaft of the engine and the first and second cam sprocket mounted on the first and second camshafts, respectively, are wound. In a chain adjuster that provides a rotating chain and presses the tensioner against the chain to give proper tension to the chain, the chain adjuster has a cylindrical body with a bottom, a plunger that slides inside the body, and the inside of the body. Since it has a spring arranged to bias the plunger in the protruding direction and a damper formed of a member capable of adjusting the repulsive force, the hydraulic pressure is not used when operating the plunger of the chain adjuster. There is no need to secure an oil passage, eliminating the need to machine oil holes in the cylinder block or cylinder head. Working process and obtained by reducing the processing cost,
It is practically and economically advantageous. Moreover, since the hydraulic pressure is not required for the operation of the plunger of the chain adjuster, the oil pump performance can be reduced as compared with the conventional one, and mechanical loss reduction and fuel consumption saving can be realized. Furthermore,
Usability can be improved by preventing problems such as clogging of oil holes. Furthermore, the number of parts can be reduced by eliminating the need for a ratchet as in the past.
Cost can be reduced. Also, if the damper is replaced, the repulsive force can be easily adjusted, which can contribute to the reduction of man-hours during engine development. Further, since the operating range of the plunger can be widened and the operating characteristics are changed, the noise from the chain can be surely reduced.

[Brief description of the drawings]

FIG. 1 is a schematic enlarged sectional view of a chain adjuster showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a plunger advancing force and a plunger protrusion amount.

FIG. 3 is a schematic diagram of an engine.

FIG. 4 is a schematic enlarged sectional view of a chain adjuster showing a second embodiment of the present invention.

FIG. 5 is a schematic enlarged sectional view of a chain adjuster showing a third embodiment of the present invention.

FIG. 6 is a schematic enlarged cross-sectional view of a chain adjuster showing a first conventional technique of the present invention.

FIG. 7 is a schematic enlarged cross-sectional view of a chain adjuster showing a second prior art of the present invention.

[Explanation of symbols]

 2 engine 4 cylinder head 6 cylinder block 8 lower case 10 crankshaft 12 first camshaft 14 second camshaft 16 crank sprocket 18 first cam sprocket 20 second cam sprocket 22 timing chain 24 first guide portion 26 second guide portion 28 Tensioner 30 Chain adjuster 32 Tensioner arm 34 Fixing bolt 36 Pad 38 Body 40 Plunger 42 Spring 44 Damper 46 Primary damper 48 Secondary damper 50 Plate

Claims (4)

[Claims] 1. A chain for winding a crank sprocket mounted on a crankshaft of an engine and first and second cam sprockets mounted on first and second camshafts, respectively, is provided, and a tensioner is pressed against the chain. In the chain adjuster that applies proper tension to the chain, the chain adjuster has a bottomed cylindrical body, a plunger that slides in the body, and the plunger is biased in the body in the protruding direction. A chain adjuster characterized in that it has a spring arranged appropriately and a damper formed of a member capable of adjusting repulsive force. 2. The chain adjuster according to claim 1, wherein the damper of the chain adjuster is a damper composed of primary and secondary dampers having different repulsive forces so as to have a change in repulsive force characteristics. 3. The damper of the chain adjuster is a damper formed of primary and secondary dampers having different repulsive forces and having a laminated structure in which the primary and / or secondary damper is composed of at least two damper members. The chain adjuster according to claim 1 of the claims. 4. A body in which the chain adjuster is formed in a cylindrical shape with a bottom, a plunger sliding in the body, a spring arranged in the plunger, and a primary damper arranged in the spring. The chain adjuster according to claim 1, which is a chain adjuster configured to include a secondary damper disposed on the bottom side of the body and contacting the spring and the primary damper via a plate.