JP2523416Y2 - Hydraulic plunger type chain tensioner - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chain tensioner in a power transmission mechanism using a chain, and more particularly to a maintenance-free chain tensioner in which a chain tension is always kept constant by a hydraulic plunger.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional example of such a hydraulic plunger type chain tensioner (Japanese Patent Laid-Open No. 61-171943). This example is an example applied to a valve drive mechanism of a four-cycle internal combustion engine, and FIG. 1 is a sectional view of a main part thereof.

A sprocket 02 fitted to a crankshaft 01
And a sprocket 04 fitted on the pair of valve operating cam shafts 03 respectively.
A tensioning slipper 06 is in sliding contact with the outside of the loose side of 05.

On the other hand, a bucket 09 is attached via a rivet 08 to a tensioner hanger 07 provided between a pair of sprockets 04.
The bucket 09 is a hollow structure formed by processing a sheet metal, has an opening that expands in a rectangular shape at the top, and has a hole that reduces the diameter in a circular shape at the bottom. The plunger body 011 of the hydraulic plunger 010 is fitted between the two rivets 08.

[0005] The spring 01 is placed on the upper part of the hydraulic plunger 010.
The plug 013 slidably fitted via 2
4 and abuts against one horizontal arm end of a bell crank 015 swinging about the center of the bell crank 015 to urge the bell crank 015 counterclockwise, and the other vertical arm end of the bell crank 015 is connected to the tensioner. It is connected to the slipper 06 via a pin 016.

Accordingly, the tensioner slipper 06 urges the cam chain 05 inward through the bell crank 015 by the protrusion of the hydraulic plunger 010 and the spring 012 to keep the tension of the cam chain 05 constant. .

[0007] The structure of the conventional example is as described above. Oil falling from the cam chain 05 or the like is collected and stored through an oil passage 07a formed in the tensioner hanger 07 and is stored in the plunger body 011 as necessary. The bucket 09 to be supplied is made by processing sheet metal.
The opening edge of the bucket 09 is not formed along the chain chamber wall surface.

[0008]

As described above, the upper opening edge of the bucket 09 does not extend along the wall surface of the chain chamber but is separated from the wall surface, so that the opening area is reduced by that amount and it becomes difficult to collect oil. Also, a large amount of oil that falls from the cam chain 05 or the like flows down the wall of the chain chamber through the oil passage 07a, and the opening edge of the bucket 09 is separated from the wall of the chain chamber. The oil that flows down and escapes to the oil pan without being collected.

It is difficult to keep the opening edge of the bucket manufactured by sheet metal working along the wall of the chain chamber at all times due to dimensional variations between the wall of the chain chamber and the bucket. So the oil passage of tensioner hanger 07
Although an oil passage is formed as in 07a to collect as much oil as possible, it takes time and cost for processing.

The present invention has been made in view of such a point.
The objective is to use a hydraulic plunger-type chain that can collect oil by making the bucket that supplies oil to the plunger body of the hydraulic plunger made of rubber, with the opening edge along the chain chamber wall surface. The point is to provide the tensioner at low cost.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a tension slipper which is always urged by a hydraulic plunger with a constant pressing force so as to slidably contact a power transmission chain and to maintain a constant chain tension. In a hydraulic plunger-type chain tensioner that automatically maintains pressure, a bucket for collecting and storing oil to supply oil to the plunger body of the hydraulic plunger is formed of rubber, and an upper opening edge of the bucket is formed along a chain chamber wall surface. This is a hydraulic plunger-type chain tensioner that is in contact.

Since the bucket is made of rubber, the opening area can be maximized by utilizing the elasticity of the bucket so that the upper opening edge comes into contact with and follows the wall of the chain chamber. The oil flowing down along the shaft can also be collected, and the oil falling from the chain or the like can be more reliably collected and supplied to the plunger body.

[0013]

[Embodiment] An embodiment of the present invention shown in FIGS. 2 to 5 will be described below. FIG. 2 is an overall side view of the motorcycle 1 applied in the present invention.

A main frame 3 is extended rightward and leftward from the head pipe 2, and a front fork 5 that supports a front wheel 4 at the lower end thereof is steerably supported by a handle 6 at the lower end of the head pipe 2. Main frame 3
The rear part of the swing arm 7 is connected to a pivot gusset 9, and a swing arm 7 is pivotally supported at the tip of the pivot gusset 9 by a pivot 8, and a rear wheel 10 is pivotally supported at the rear end of the swing arm 7. ing.

A fuel tank 11 is supported on the upper portion of the main frame 3, and a seat is provided behind the fuel tank 11.
12 are arranged. An engine 20 is suspended below the main frame 3 by an engine hanger 13 and the pivot gusset 9.

The engine 20 is a horizontal V-type four-cylinder engine. FIG. 3 shows a valve drive system of the engine 20. A crankcase is formed by a vertically divided cylinder block 21 and a lower crankcase 22, and a front cylinder head 23 is connected to an obliquely forward opening of the cylinder block 21 and a pair of left and right fronts projecting obliquely forward inside the cylinder block 21. The cylinder is accommodated, and the front head cover 24 covers the upper part. Similarly, a rear cylinder head 25 is connected to an obliquely rear opening of the cylinder block 21 to receive a pair of left and right rear cylinders, and a rear head cover 26 covers an upper part.

The valve drive mechanism is arranged in a cam chain chamber 76 on the left side of the cylinder along the left side walls of the cylinder block 21, cylinder heads 23, 25 and head covers 24, 26.

V formed by the front and rear cylinder heads 23 and 25
The crankshaft 30 is located at the center bending part of the
A timing gear 31 is fitted to 30 and the timing gear 31
The idle gears 32 and 33 mesh with the idle gears 32 and 33.
The idle sprockets 34 and 35 are provided coaxially with the sprocket. On the other hand, a pair of camshafts 36, 36, 37, and 37 are provided so as to be oriented in the left-right direction and covered by the head covers 24 and 26, respectively. , 38, 39, 39 are fitted.

A cam chain 40 is bridged between the front cam sprockets 38, 38 and the idle sprocket 34, and the rear cam sprockets 39, 39 and the idle sprocket 35
And a cam chain 41 is bridged between them.

Therefore, in FIG. 3, the rotation of the crankshaft 30 in the counterclockwise direction is
The idle sprockets 34 and 35 are rotated clockwise by the engagement of the gears 2 and 33. The rotation of the idle sprockets 34 and 35 is achieved by rotating the cam shafts 36 and 37 clockwise at predetermined timings via the cam chains 40 and 41. become.

The front and rear valve drive mechanisms have the same structure, and a chain guide 4 slidingly contacting the outer surfaces of the cam chains 40 and 41 is provided on the tight side of the cam chains 40 and 41 (right side in FIG. 3).
2 and 43 are provided, and chain guides 44 and 45 are provided inside the head covers 24 and 26 between the cam sprockets 38 and 38 and between the cam sprockets 39 and 39, respectively.
It comes into sliding contact with the outer surfaces of 40 and 41.

Then, the loose side of the cam chains 40 and 41 (FIG. 3)
On the left side, tensioner slippers 46 and 47 are pivotally supported at one ends by pivots 48 and 49, and are swingably provided.
It keeps the tension of 0,41.

The chain tensioner using the tension slippers 46 and 47 is a maintenance-free automatic tensioning device, and its structure will be described with reference to an enlarged view of the front chain tensioner (FIG. 4).

Inside the cam chain 40, a hydraulic plunger 50 is slidably fitted to a plunger body 54 at substantially the center of the three sprockets 34, 38, 38.
The plunger body 54 is provided with a pivot 56 projecting from the front cylinder head 23 at the lower end of the cylinder opening upward.
The plunger 50, which is pivotally supported at the rear and is directed obliquely upward and rearward, is inserted into the plunger body 54 from above by closing the upper opening portion with a plug 52 to form a cylindrical space inside. 50a is formed.

A tensioner arm 60 is rotatably connected to a plunger 52 fitted in an upper end opening of the plunger 50 via a joint pin 58, and the tensioner arm 60 extends below the joint pin 58. The lower end is connected to the vicinity of the free end of the tension slipper 46 via a joint pin 62.

The tensioner arm 60 has a shape in which rear end edges of a pair of left and right plate members are connected by a connecting portion 60a. The connecting portion 60a is provided with a guide pin 64 projecting from a predetermined position of the cylinder block 21. To the tensioner arm 60 by the guide pin 64.
And is prevented from falling backward, and is regulated to move along the guide pin 64.

In the plug 52 fitted to the upper end of the hydraulic plunger 50, the flange 52a is in contact with the upper opening end face of the plunger body 54 and extends further outward from the opening end face. A plunger spring 66 is interposed between the opening end surface and the plunger spring 66 to urge the hydraulic plunger 50 upward.

Therefore, the plunger 50 is configured so as to urge the tension slipper 46 to swing upward through the tensioner arm 60 by the plunger spring 66 to press the cam chain 40 inward to maintain the tension.

An orifice 50b is formed in the bottom wall of the lower end of the plunger 50 to provide a high-pressure chamber 68 formed between the closed end of the plunger body 54 and the bottom wall of the plunger 50, and the internal space 50a of the plunger 50. And the orifice 50b communicate with each other. A plunger check ball 70 is provided at the opening of the orifice 50b on the high pressure chamber 68 side so as to be able to contact and separate therefrom. One way is to allow the oil to flow from the internal space 50a to the high pressure chamber 68 from the internal space 50a and to block the flow in the opposite direction. Make up the valve.

A through hole 50c communicating with the internal space 50a is formed in a part of the upper side of the side wall of the plunger 50 inserted into the plunger body 54, and the side wall of the plunger body 54 corresponds to the through hole 50c. A long hole 54a, which is longer than the through hole 50c in the axial direction, is formed in a part of the upper part. Space 50a
Is in communication with the outside.

A bucket 72 is provided upright with the side wall of the plunger body 54 including the elongated hole 54a as a bottom wall.
The bucket 72 is made of rubber, and has a rectangular opening formed downward along the obliquely inclined side wall of the plunger body 54, and a lower opening edge 72a is baked along the cylindrical outer surface of the plunger body 54. It is fixed.

The bucket 72 has a side wall extending upward from the lower opening edge 72a while gradually increasing the left-right width and the front-rear width, and extending vertically upward from an appropriate height to form a large rectangular opening upward. An oil reservoir 74 is formed.

The upper end opening surface is horizontal, and the upper end opening edge 72
b has a gradually decreasing wall thickness and is open outward, and its left and right edges abut along the cylinder head side wall of the cam chain chamber 76 (see FIG. 5). The bottom wall of the bucket 72 is formed by an inclined side wall of the plunger body 54, and a long hole 54a is located below the bottom wall.

FIG. 5 is a sectional view taken along the line V--V in FIG. 4, showing a cylinder block 21 and a cam chain chamber formed along left outer walls 21a, 23a of a front cylinder head 23.
A valve train drive mechanism including the cam chain 40 and a hydraulic plunger type chain tensioner are provided in 76.

A bucket 72 having a lower end burned and fixed to the plunger body 54 is located in the cam chain chamber 76 between the left outer wall 23a and the inner wall 23b of the front cylinder head 23, and the upper opening edge 72b has both side walls. It contacts along 21a and 21b.

A cam chain is provided above the bucket 72.
The upper opening of the bucket 72 collects oil that falls from the cam sprocket 38 and the cam sprocket 38.

A tappet oil return passage 77 having an opening in the cam chain chamber 76 is formed in the front cylinder head 23 at a position above the upper opening edge 72b of the bucket 72, and tappet oil or a cam journal (not shown). The oil that has fallen from the cam chain chamber
It enters 76 and is collected in a bucket 72.

As described above, since the bucket 72 is made of rubber, the upper opening area can be increased to the extent that it comes into contact with the side wall of the cam chain chamber 76, so that the upper cam chain 40
In addition to increasing the area for collecting oil falling from the cam sprocket 38 and the upper opening edge 72b of the bucket 72 abutting along the side walls 23a and 23b of the cam chain chamber 76, the bucket 72 travels along the side walls 23a and 23b. Oil flowing down is also collected by the opening edge 72b.

There is a considerable amount of oil flowing down the side wall, and oil entering the cam chain chamber 76 from the passage 77 is considered to flow down the inner wall 23b. The amount of oil collected by the opening edge 72b is considerable, and the oil collection rate is several steps higher than in the past.

Since the bucket 72 is made of rubber,
The upper opening edge 72b can be easily abutted along the wall surface even if the wall surface is somewhat rough due to dimensional variations between the 23a and 23b and the casting surface.

The oil collected and stored in the oil reservoir 74 of the bucket 72 fills the internal space 50a of the plunger 50 through the long hole 54a and the through hole 50c, and the slack side of the cam chain 40 is further loosened. In this case, the hydraulic plunger 50 moves upward due to the resilient force of the plunger spring 66, and the movement of the hydraulic plunger 50 causes the pressure in the high-pressure chamber 68 to drop, thereby releasing the closing of the orifice of the plunger check ball 70, and the oil flowing into the orifice 50b Through the high pressure chamber
The pressure in the high pressure chamber 68 is increased again, and the plunger check ball 70 is again pressed against the opening of the orifice 50b to close the orifice 50b.

Since the oil does not flow backward through the orifice 50b due to the plunger check ball 70, the plunger 50 moves upward each time the cam chain 40 is loosened, and swings the tension slipper 46 via the tensioner arm 60 to cause the cam chain to move. 40 tensions can be maintained automatically. Therefore, the large amount of oil collected by the bucket 72 means that the oil can be reliably supplied to the high-pressure chamber 68.

The chain tensioner in the rear valve drive mechanism has substantially the same structure, and the plunger
51, plug 53, plunger body 55, pivot 57, tensioner arm 61, guide pin 65, plunger spring
67, high pressure chamber 69, plunger check ball 71, bucket
Consists of 73.

However, the overall inclination is different, and the plunger 5
1. Since the plunger body 55 is also inclined obliquely downward and backward from the pivot 57 supporting the plug 53 of the plunger 51, the bucket 73 is fixed to the plunger body 55 by baking so as to have an opening upward.

In the case of the V-type engine as in the present embodiment, the front plunger body 54 and the rear plunger body 55 are inclined in the opposite directions, but are arranged at the same mounting angle with respect to the horizontal so that the front and rear plungers are arranged in front and rear. The same bucket 72 and bucket 73 can be used in common, and there is no need to increase the types of parts. That is, as shown in FIG.
Reverse the front and rear of the same shape bucket 7
Since the upper opening surface is made horizontal by fixing to both the buckets 2 and 73, buckets having the same shape can be commonly used.

In general, when a hydraulic plunger-type chain tensioner is adopted, since complicated oil holes such as thick oil supply passages such as blocks to be installed and holes for mounting a brazier body are not required, existing machining holes are not required. Even if a chain tensioner that does not have the automatic tension adjustment function is attached, it can be easily replaced with the maintenance-free chain tensioner of the present invention and has compatibility.

[0047]

According to the present invention, the bucket of the hydraulic plunger type chain tensioner is made of rubber and the upper opening edge is brought into contact with the wall of the chain chamber, so that the area of the upper opening is increased and the water flows down the wall. Oil can also be collected, and the oil can be collected more reliably.

The bucket can be easily attached to the plunger body by baking rubber, and even when applied to a V-type engine, an inexpensive maintenance-free chain tensioner can be provided by using the bucket in common in front and rear to keep the number of parts low. Can be offered.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a conventional hydraulic plunger type chain tensioner and an internal combustion engine.

FIG. 2 is an overall side view of the motorcycle to which the present invention is applied.

FIG. 3 is a cross-sectional view of a main part of a V-type engine mounted on the motorcycle.

FIG. 4 is an enlarged view of the main part.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... motorcycle, 2 ... head pipe, 3 ... main frame, 4 ... front wheel, 5 ... front fork, 6 ... steering wheel,
7 ... swing arm, 8 ... pivot, 9 ... pivot gusset, 10 ... rear wheel, 11 ... fuel tank, 12 ... seat,
13 ... engine hanger, 20 ... engine, 21 ... cylinder block, 22 ... lower crankcase, 23 ... front cylinder head, 24 ... front head cover, 25 ... rear cylinder head, 26 ... rear head cover, 30 ... crankshaft, 31
... Timing gear, 32,33 ... Idle gear, 34,35 ... Idle sprocket, 36,37 ... Cam shaft, 38,39 ... Cam sprocket, 40,41 ... Cam chain, 42,43,44,45 ...
Chain guide, 46, 47… Tensioner slipper, 48,
49… Pivot, 50,51… Plunger, 52,53… Plug,
54, 55 ... Plunger body, 56, 57 ... Pivot, 58 ... Joint pin, 60, 61 ... Tensioner arm, 62 ... Joint pin, 64, 65 ... Guide pin, 66, 67 ... Plunger spring, 68, 69 ... High pressure chamber , 70, 71 ... plunger check ball, 72, 73 ... bucket, 74 ... oil reservoir, 76 ... cam chain chamber.

Claims (1)

(57) [Scope of request for utility model registration] 1. A hydraulic plunger type chain tensioner in which a tension slipper constantly urged by a hydraulic plunger with a constant pressing force slides on a power transmission chain to automatically maintain a constant chain tension. A hydraulic plunger-type chain tensioner, wherein a bucket for collecting and storing oil for supplying oil to a plunger body is made of rubber, and an upper opening edge of the bucket is abutted along a wall of a chain chamber.