JP2003056320A - Valve system mechanism of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent incorrect assembly of an actuator of a variable valve timing device by improving the degree of layout freedom of a cam chain tensioner. SOLUTION: The valve system mechanism 20 of an engine has a timing chain 42, a cam chain, can chain tensioner 50B and an actuator 64B of a variable valve timing device 62. The timing chain 42 is wound around a crank sprocket and an intermediate sprocket, a cam chain is wound around an intake/ exhaust cam sprocket and an intermediate shaft cam sprocket. The cam chain tensioner 50B applies constant tension to this cam chain, and the actuator 64B of the variable valve timing device 62 makes either of an intake/exhaust cam shaft 22B or 24B change the rotation phase for the crankshaft. In this valve mechanism 20 of the engine, the cam chain tentioner is disposed on the inner side of a chain line of a cam chain 44B and is attached to a cylinder head 6B with a mounting bolt. Also a clearance groove for a tool is formed, which is used when a mounting bolt is secured to the outer periphery of the actuator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine valve mechanism, and more particularly to a cam chain tensioner which can be mounted on a portion which is difficult to mount due to interference with an actuator of a variable valve timing device. The present invention relates to a valve operating mechanism for an engine, which can increase the flexibility of layout of a tensioner and prevent erroneous assembly of an actuator of a variable valve timing device.

[0002]

2. Description of the Related Art An engine mounted on a vehicle is provided with a valve mechanism for opening and closing intake / exhaust valves. As a valve operating mechanism of an engine, there is one shown in FIG. In FIG. 9, 102 is an engine, 104 is a cylinder block, 1
Reference numeral 06 is a cylinder head. The valve mechanism 108 of the engine 102 is provided with a crank sprocket on a crank shaft (not shown) pivotally supported on the cylinder block 104, and an intake / exhaust cam shaft 110 pivotally supported on the cylinder head 106.
・ 112 intake and exhaust cam sprocket 114 ・ 1 respectively
16, an intermediate shaft 118 attached to the cylinder head 106 is provided with an intermediate sprocket 120 and a cam sprocket 122.

The engine 102 includes a crank sprocket, an intermediate sprocket 120, and a timing chain 1.
Intake / exhaust cam sprocket 11
A cam chain 126 is provided by being wound around the 4.116 and the sprocket 122 for cam. Also, the engine 102
Is provided with a cam chain tensioner 128 that applies a constant tension to the cam chain 126. The cam chain tensioner 128 is disposed inside the chain line (chain traveling locus) of the cam chain 126 and between the intake cam shaft 110 and the intermediate shaft 120.

The cam chain tensioner 128 is provided on the tensioner main body 130 so as to hold a pusher body 132 so as to be able to move forward and backward toward the cam chain 126, and to push the pusher body 132 toward the cam chain 126. A force imparting means (not shown) is provided on the tensioner body 130. The cam chain tensioner 128 mounts the tensioner main body 130 to the cylinder head 106 with mounting bolts 134.
The mounting bolts 138 are mounted by the mounting bolts 138 and are mounted on the cylinder head 106 to support the intermediate sprocket 120 and the cam sprocket 122.

The valve mechanism 10 of the engine 102 is also used.
8 is a variable valve timing device 140 for changing the rotational phase of either the intake / exhaust cam shaft 110 or 112, or the intake cam shaft 110 in the figure, with respect to the crankshaft.
Actuator 142 is provided. The actuator 142 is mounted on the intake cam shaft 110, and a vane chamber (not shown) which is mounted on the intake cam sprocket 114 and is mounted on the intake cam sprocket 114 so as to be rotatable relative to the rotor, and which expands and contracts between the rotor and the rotor. No)
And a housing 144 for partitioning.

The valve operating mechanism 108 of the engine 102 has an intake / rotating mechanism in which the rotation of a crankshaft (not shown) pivotally supported by the cylinder block 104 is pivotally supported by the cylinder head 106 via a timing chain 124 and a cam chain 126. It is transmitted to the exhaust cam shafts 110 and 112 to drive an intake / exhaust valve (not shown). In addition, the valve mechanism 108
Changes the rotational phase of the intake camshaft 110 with respect to the crankshaft by means of the actuator 142 of the variable valve timing device 140 provided on the intake camshaft 110.
The opening / closing timing of the exhaust valve (not shown) is changed.

As a valve operating mechanism for such an engine,
There is one disclosed in Japanese Patent Laid-Open No. 1998-280604. What is disclosed in the publication is that the cam chain tensioner is arranged inside the cam chain,
The tensioner body has a cylinder head mounting boss that is mounted on the cylinder head inside the cam chain with mounting bolts, and an intermediate shaft mounting boss that is mounted with an intermediate shaft mounting nut on the intermediate shaft mounting bolt of the intermediate shaft. Is.

[0008]

By the way, as shown in FIG.
In the valve operating structure 108 of the engine 102 shown in FIG. 5, the tightening position of the mounting bolt 134 to the cylinder head 106 of the cam chain tensioner 128 is variable valve timing device 1.
It is located close to the 40 actuators 142.

For this reason, the cam chain tensioner 128
When mounting the tensioner body 130 to the cylinder head 106 with the mounting bolts 134, the mounting bolts 134
The tool (not shown) used for tightening the cam may interfere with the housing 144 of the actuator 142, and the tightening may be hindered to make it impossible to mount the cam chain tensioner 128. As a result, the mounting position may be changed. Therefore, there is an inconvenience that the degree of freedom in layout is hindered.

Further, when the mounting position of the mounting bolt 134 is changed to a position where interference with the actuator 142 can be avoided and the cam chain tensioner 128 is mounted, the tightening balance is impaired and sufficient mounting strength is obtained. There is a problem in that it is difficult to secure it, and it is necessary to increase the number of tightening points by the mounting bolts, which causes an inconvenience of increasing the number of parts and the number of assembling steps.

[0011]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a crank sprocket on a crank shaft which is axially supported by a cylinder block of an engine,
Intake / exhaust cam sprockets are provided on the intake / exhaust cam shafts that are axially supported by the cylinder head of the engine, and intermediate sprockets and cam sprockets are provided on the intermediate shaft that is attached to the cylinder head. A timing chain is wound around the sprocket, a cam chain is wound around the intake / exhaust cam sprocket and the cam sprocket, and a cam chain tensioner is provided to give a certain tension to the cam chain. In a valve operating mechanism of an engine in which an actuator of a variable valve timing device that changes a rotation phase with respect to the crankshaft is provided on either one of the camshafts, the cam chain tensioner is arranged inside a chain line of the cam chain, Cam chain tension The is characterized in that provided by forming a relief groove of the tool that is used when tightening the mounting bolts to the outer periphery of the actuator provided with attached by a mounting bolt to the cylinder head.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An engine valve operating mechanism of the present invention has a cam chain tensioner disposed inside a chain line of a cam chain, the cam chain tensioner being mounted on a cylinder head with mounting bolts, and a variable valve. By forming an escape groove for the tool used when tightening the mounting bolt on the outer periphery of the actuator of the timing device, the tightening position of the mounting bolt to the cylinder head of the cam chain tensioner should be close to the actuator. Even if it is, it is possible to prevent the tool used for tightening the mounting bolt from interfering with the actuator due to the relief groove of the actuator.Also, when tightening the mounting bolt of the cam chain tensioner, this mounting bolt and variable valve Relief groove of timing device actuator It is necessary to match, it is possible to check the correctness of the assembly position of the actuator of the variable valve timing device.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment of the present invention. In FIG. 5, 2 is an engine. In this engine 2, first and second cylinder heads 6A and 6B are mounted on the upper portion of a cylinder block 4, respectively, and first and second head covers 8A and 8B are provided on the upper portions of these first and second cylinder heads 6A and 6B. The first and second cylinder banks 10A and 10B are arranged in a V shape by being attached, and a space 12 is formed between the first and second cylinder banks 10A and 10B.

In the engine 2, a crankcase 14 is attached to a lower portion of a cylinder block 4 to rotatably support a crankshaft 16, an oil pump 18 is attached to a lower portion of the crankcase 14, and the crankcase 14 is covered so as to cover the oil pump 18. An oil pan (not shown) is attached to the bottom of the.

The engine 2 is provided with a valve mechanism 20 for driving intake / exhaust valves (not shown). Valve mechanism 20
The first intake / exhaust camshaft 2 on the first cylinder head 6A.
The second cylinder head 6B is provided by axially supporting 2A and 24A.
The second intake / exhaust cam shafts 22B and 24B are axially supported.

A crank sprocket 26 is attached to one end of the crankshaft 16 in the axial direction.
The first intake camshaft 22A has a first
The intake cam sprocket 28A is provided so as to be rotatable relative to the exterior. A first exhaust cam sprocket 30A is attached and provided on one end side in the axial direction of the first exhaust cam shaft 24A. A second intake cam sprocket 28B is provided on the one end side in the axial direction of the second intake cam shaft 22B so as to be relatively rotatable and externally mounted. A second exhaust cam sprocket 30B is attached and provided on one end side in the axial direction of the second exhaust cam shaft 24B.

The first intake cam shaft 22A is provided with a first intermediate sprocket 32A attached to the outside of the first intake cam sprocket 28A in the axial direction. An intermediate shaft 34 is attached to one end of the second cylinder head 6B in the axial direction so as to be located between the second intake / exhaust cam shafts 22B and 24B and the crank shaft 16. This intermediate shaft 3
No. 4 on the second side by means of an intermediate shaft mounting bolt 82B, which will be described later.
A second intermediate sprocket 32B and a second cam sprocket 36, which are attached to the second cylinder head 6B together with the cam chain tensioner 50B and are integrally formed, are axially supported. An idler shaft 38 is attached to one end of the cylinder block 4 in the axial direction so as to be positioned above the center in the width direction, and an idler sprocket 40 is pivotally supported on the idler shaft 38.

The crank sprocket 26, the first intermediate sprocket 32A, and the second intermediate sprocket 32B.
A timing chain 42 is wound around the idler sprocket 40 and the idler sprocket 40. The first cam chain 4 is attached to the first intake / exhaust cam sprockets 28A and 30A.
It is provided by winding 4A. A second cam chain 44B is wound around the second intake / exhaust cam sprockets 28B and 30B and the second cam sprocket 36.

The timing chain 42 is provided with a timing chain tensioner 46 for applying a constant tension, and a timing chain guide 48 for stabilizing traveling. The timing tensioner 46 and the timing chain guide 48 are attached to one end of the cylinder block 4 in the axial direction.

The first cam chain 44A is provided with a first cam chain tensioner 50A which gives a constant tension. The first cam chain tensioner 50A is attached and provided on one end side in the axial direction of the first cylinder head 6A. The second cam chain 44B is provided with a second cam chain tensioner 50B that applies a constant tension.
The second cam chain tensioner 50B is attached and provided on one end side in the axial direction of the second cylinder head 6B.

The engine 2 has a crankshaft 16
Of the crankshaft sprocket 26 of FIG.
The pump side sprocket 56 is attached to the pump shaft 54 of No. 8 and the pump driving chain 58 is wound around the pump driving sprocket 52 and the pump side sprocket 56.

The timing chain 42, the first cam chain 44A, the second cam chain 44B, the timing chain tensioner 46, the timing chain guide 4
8, the first cam chain tensioner 50A, the second cam chain tensioner 50B, the pump drive chain 58,
It is covered by the chain cover 60.

The valve mechanism 20 is provided with a variable valve timing device 62. Variable valve timing device 6
2 is provided with a first actuator 64A for changing the rotation phase with respect to the crankshaft 16 on one of the first intake / exhaust cam shafts 22A, 24A, and on one of the second intake / exhaust cam shafts 22B, 24B. Second actuator 64B for changing the rotation phase with respect to the crankshaft 16
Is provided to divide the oil discharged from the oil pump 18 into advance oil and retard oil.
The chain cover 60 is provided with first and second oil control valves 66A and 66B for supplying the actuators 64A and 64B, respectively.

In this embodiment, the first intake camshaft 2
2A axially one end side, the first with respect to the crankshaft 16
A first actuator 64A for changing the rotation phase of the intake cam shaft 22A is provided. Further, in this embodiment, a second actuator 64B that changes the rotational phase of the second intake cam shaft 22B with respect to the crankshaft 16 is provided at one end side in the axial direction of the second intake cam shaft 22B.

As a result, the valve mechanism 20 of the engine 2
The rotation of the crankshaft 16 supported by the cylinder block 4 is supported by the first cylinder head 6A and the second cylinder head 6B via the timing chain 42 and the first and second cam chains 44A and 44B. 1 intake / exhaust cam shaft 22A / 24 and second intake / exhaust cam shaft 22B /
24B, the first intake / exhaust valve and the second intake /
An exhaust valve (not shown) is driven. In addition, this valve operating mechanism 1
08 of the first and second intake camshafts 22A and 22B relative to the crankshaft 16 by the first and second actuators 64A and 64B of the variable valve timing device 62 provided on the first and second intake camshafts 22A and 22B. The rotation phase is changed to change the opening / closing timings of the first intake / exhaust valve and the second intake / exhaust valve (not shown), respectively.

As shown in FIG. 1, the valve mechanism 20 applies a constant tension to the second cam chain 44B wound around the second intake / exhaust cam sprockets 28B and 30B and the second cam sprocket 36. The inside of the second cam chain tensioner 50B surrounded by the chain line (chain traveling locus) of the second cam chain 44B,
The second intake cam shaft 22B and the intermediate shaft 34 are positioned and arranged.

The second cam chain tensioner 50B is provided with a second tensioner body 68B having a substantially triangular frame shape.
A pusher 70B is provided on the tensioner main body 68B so as to be able to advance and retreat toward the second cam chain 44B, and the pusher 70B pushes the pusher 70B toward the second cam chain 44B to impart tension to the tensioner main body 68B. Providing means (not shown) is provided on the second tensioner body 68B.

The second cam chain tensioner 50B is for a second cylinder head which is located at two apexes of the second tensioner main body 68B having a substantially triangular frame shape and is attached to the second cylinder head 6B inside the second cam chain 44B. The mounting boss portions 72B and 74B are provided, and the intermediate shaft mounting boss portion 76B which is located at one vertex and is mounted on the second cylinder head 6B together with the intermediate shaft 34 by the intermediate shaft mounting bolt 82B described later is provided. ing.

The second cam chain tensioner 50B is provided with the second cylinder head mounting boss portions 72B and 74B of the second tensioner body 68B mounted on the second cylinder head 6B by the second cylinder head mounting bolts 78B and 80B, respectively. The intermediate shaft mounting boss portion 76B is mounted on the second cylinder head 6B together with the intermediate shaft 34 by the intermediate shaft mounting bolts 82B.

Further, as shown in FIGS. 2 to 4, the valve operating mechanism 20 is variable to change the rotational phase of the second intake cam shaft 22B with respect to the crankshaft 16 to one end side in the axial direction of the second intake cam shaft 22B. A second actuator 64B of the valve timing device 62 is provided. Second actuator 64
B is located close to the tightening position of the second cylinder head mounting bolt 78B of the second cam chain tensioner 50B.

The second actuator 64B is mounted on the second intake cam shaft 22B by a mounting bolt 84B, and is mounted on the second intake cam sprocket 28B so as to be rotatable relative to the second rotor 86B. The second housing 92B defines a second vane chamber 90B that is mounted by a bolt 88B and expands and contracts with the second rotor 86B.

The outer periphery of the second housing 92B of the second actuator 64B is used for tightening the second cylinder head mounting bolt 78B of the second cam chain tensioner 50B, which is adjacent thereto, as shown in FIGS. A relief groove 94B for a tool (not shown) is formed and provided.
The relief groove 94B is formed and provided in a shape along the outer peripheral edge of the operation area S of the tool that is rotated when tightening the second cylinder head mounting bolt 78B, and the tightening direction. It is formed so as to extend to.

The relief groove 94B is for the second cylinder head of the second actuator 64B which is rotationally positioned at the specified position when the second actuator 64B is rotationally positioned at the specified position of the rotational phase with respect to the crankshaft 16. It is formed and provided at a position facing the tightening position of the mounting bolt 78B. Further, the escape groove 94B is formed so as to be located between the adjacent second vane chambers 90B of the second actuator 64B.

Next, the operation will be described.

The valve operating mechanism 20 of the engine 2 is provided with a crank sprocket 26 on a crank shaft 16 supported by a cylinder block 4, and a first and second cylinder head 6A.
.First intake / exhaust cam shafts 22A and 24 which are pivotally supported by 6B
A and the first intake / exhaust camshafts 22B and 24B are respectively provided with the first
The intake / exhaust cam sprocket 28A / 30A and the second intake / exhaust cam sprocket 28B / 30B are provided to
The intake camshaft 22A is provided with a first intermediate sprocket 32A, and the intermediate shaft 34 is attached to the first cylinder head 6A.
Is provided with a second intermediate sprocket 32B and a second cam sprocket 36.

The valve operating mechanism 20 includes the crank sprocket 2
6, the first intermediate sprocket 32A and the second intermediate sprocket 32B are provided by winding the timing chain 42, and the first intake / exhaust cam sprocket 28A, 30A is provided by winding the first cam chain 44A. The first and second cams which provide a constant tension to the first and second cam chains 44A and 44B by winding the second cam chain 44B around the intake / exhaust cam sprockets 28B and 30B and the second cam sprocket 36. Chain tensioner 50A
50B is provided for the first and second intake / exhaust cam shafts 22A / 2.
4A is provided with first and second actuators 64A and 64B of the variable valve timing device 62 that changes the rotational phase with respect to the crankshaft 16.

In the valve mechanism 20 of the engine 2, the second intake cam sprocket 28B is provided on the second intake cam shaft 22B when it is assembled, and the second exhaust cam shaft 2 is also provided.
4B, the second exhaust cam sprocket 30B is attached, and the second intake / exhaust cam sprocket 28B / 30B and the second cam sprocket 36 are connected to the second cam chain 44.
B is wound around, the second rotor 86B of the second actuator 64B is attached to the second intake cam shaft 22B, and the second housing 92B is attached to the second intake cam sprocket 28 screw. 2nd cam chain tensioner 50 inside the chain line of
B is provided, the second cam chain tensioner 50B is provided by being attached to the second cylinder head A by the second cylinder head mounting bolts 78B and 80B, and the second cam chain tensioner 50B is also attached to the intermediate shaft 34 by the intermediate shaft mounting bolt 82B. It is attached to the cylinder head 6B.

The second of the second cam chain tensioner 50B
On the outer periphery of the second housing 92B of the second actuator 64B of the variable valve timing device 62, which is close to the tightening position of the cylinder head mounting bolt 78B, there is a tool used when tightening the second cylinder head mounting bolt 78B. The escape groove 94B is formed and provided.

As a result, the valve mechanism 2 of the engine 2 is
Even if the tightening position of the mounting bolt 78B for the second cylinder head of the second cam chain tensioner 50B is close to the second actuator 64B, the second value is 0 due to the escape groove 94B formed on the outer periphery of the second actuator 64B.
The tool used for tightening the cylinder head mounting bolt 78B can be prevented from interfering with the second actuator 64B, and the tool can be operated in the operation area S to tighten the second cylinder head mounting bolt 78B. it can.

Therefore, the valve mechanism 20 interferes with the second actuator 64B of the variable valve timing device 62 which is close to the second cam chain tensioner 50B, so that the mounting bolt 78B for the second cylinder head of the second cam chain tensioner 50B. Of the variable valve timing device 62 due to interference with the second actuator 64B of the variable valve timing device 62 can be attached to a portion that is difficult to attach, and the layout of the layout can be improved. The degree of freedom can be increased.

In addition, since the valve mechanism 20 does not need to change the tightening position of the second cylinder head mounting bolt 78B to a position where interference with the second actuator 64B can be avoided, the tightening balance can be improved. There is no need to increase the number of tightening points by the second cylinder head mounting bolts 78B without causing a problem that it is difficult to secure sufficient mounting strength due to damage to the second cylinder head, which may increase the number of parts and the number of assembling steps. In addition, since it can be tightened at the optimum position, it is possible to secure a sufficient tightening force even if the second cylinder head mounting bolt 80B is omitted as shown in FIG. And the number of assembly steps can be reduced.

Further, the valve mechanism 20 of the engine 2
When tightening the second cylinder head mounting bolt 78B of the second cam chain tensioner 50B, the second cylinder head mounting bolt 78B and the relief groove 94B of the second actuator 64B of the variable valve timing device 62 are provided.
Since it is necessary to match with, it is possible to confirm whether the mounting position of the second actuator 64B of the variable valve timing device 62 is correct. Therefore, the valve mechanism 20 can prevent the erroneous assembly of the second actuator 64B of the variable valve timing device 62 when tightening the second cylinder head mounting bolt 78B of the second cam chain tensioner 50B. .

The relief groove 94B is provided with a second cylinder head mounting bolt 78 of the second actuator 64B which is rotationally positioned at a prescribed position of the rotational phase with respect to the crankshaft 16.
It is formed and provided at a position facing the tightening position of B.
Therefore, the escape groove 94B is provided with the second actuator 64B.
Can be used as an alignment mark for the
It is not necessary to form the alignment mark on the actuator 64B or the cylinder block 4, and the alignment can be easily performed.

The escape groove 94B is formed so as to be located between the adjacent second vane chambers 90B of the second actuator 64B. For this reason, the escape groove 94B has the second groove.
There is no interference with the second vane chamber 90B of the actuator 64B, and the function of the second actuator 64B is not impaired.

Further, the second cam chain tensioner 50
B is disposed inside the chain line of the second cam chain 44B and between the second intake cam shaft 22B and the intermediate shaft 34, and is attached to the second cylinder head 6B by the second cylinder head mounting bolts 78B and 80B. In addition to being attached, the second intermediate sprocket 32B and the second cam sprocket 36 are attached to the second cylinder head 6B together with the intermediate shaft 34 that pivotally supports the second intermediate sprocket 32B and the second cam sprocket 36. Therefore, the second cam chain tensioner 50B can be fastened together with the intermediate shaft 34 to be attached to the second cylinder head 6B, the number of parts and the number of assembling steps can be reduced, and the second cylinder head 6B can be firmly fixed. Can be fixed to.

FIG. 7 shows a second embodiment. In the valve mechanism 20 of the second embodiment, the second attachment boss 72B is provided on the second tensioner main body 68B of the second cam chain tensioner 50B which is close to the second actuator 64B of the variable valve timing device 62. Boss 72
A second cylinder head mounting bolt 78B for mounting B on the second cylinder head 6B is provided, and the operation range S of the tool (not shown) used when tightening the second cylinder head mounting bolt 78B is the second actuator. The second housing 92B of 64B does not come into contact with the outer peripheral edge of the second housing 92B.
The mounting boss portion 72B is formed so as to be inclined with respect to the second intake cam shaft 22B.

In the valve mechanism 20 of the second embodiment, the operation range S of the tool of the second cylinder head mounting bolt 78B of the second cam chain tensioner 50B, which is close to the second actuator 64B of the variable valve timing device 62, is set. , The second attachment boss 72B so as not to contact the second housing 92B of the second actuator 64B.
Since the tool is formed so as to be inclined with respect to 2B, it is possible to prevent the tool from interfering with the second actuator 64B, and operate the tool in the operation area S to mount the second cylinder head mounting bolt 78B. Can be tightened.

Therefore, the valve mechanism 20 can operate without interfering with the second actuator 64B of the variable valve timing device 62 without hindering the tightening of the second cylinder head mounting bolt 78B of the second cam chain tensioner 50B. Therefore, the second cam chain tensioner 64B can be attached to a portion that is difficult to attach due to the interference with the second actuator 64B of the variable valve timing device 62, and the degree of freedom of layout can be increased.

FIG. 8 shows a third embodiment. The valve mechanism 20 of the second embodiment includes a second tensioner on the second cylinder head mounting boss portion 72B of the second tensioner body 68B of the second cam chain tensioner 50B which is close to the second actuator 64B of the variable valve timing device 62. The side engagement protrusion 96B is formed and provided, and the second head side engagement recess 98B with which the second tensioner side engagement protrusion 96B is engaged is formed and provided in the second cylinder head 6B. The second tensioner-side engaging projection 96B is projected from the second tensioner main body 68B and is inclined from the second cylinder head mounting boss portion 72B side toward the second cylinder head mounting boss portion 74B side. The second tensioner side engagement surface 96B-P is formed and provided. The second head-side engagement recess 98B has a second tensioner-side engagement surface 96.
A second head side engagement surface 98B-P is formed so as to be inclined so as to engage with B-P.

In the valve mechanism 20 of the third embodiment, the second tensioner side engaging protrusion 96B of the second cam chain tensioner 50B and the second cylinder head 6B which are close to the second actuator 64B of the variable valve timing device 62. To engage the second head-side engaging recess 98B to attach the second cylinder head mounting boss 74B to the second starting mounting bolt 8
By attaching to the second cylinder head 6B by 0B, the second cam chain tensioner 50B can be attached without the need for the second cylinder head attaching bolt 78B, and the second cylinder head attaching boss portion 72 can be attached.
The second tensioner side engaging surface 96B- which is inclined from the B side toward the second cylinder head mounting boss portion 74B side.
By engaging P with the second head side engagement surface 98B-P, it is possible to support the reaction force with respect to the pushing force of the pushing body 70B.

Therefore, the valve mechanism 20 can allow the second cam chain tensioner 64B to be attached to a portion which is difficult to attach due to the interference with the second actuator 64B of the variable valve timing device 62, and the layout is free. The second cylinder head mounting bolt 78B and the tightening work can be eliminated, the number of parts and the assembly man-hour can be reduced, and the second pushing force of the pushing body 70B can be used. The position shift of the cam chain tensioner 50B can be prevented, the fluctuation of the tension of the second cam chain 44B can be prevented, and the looseness can be prevented.

[0052]

As described above, according to the engine valve mechanism of the present invention, even if the tightening position of the mounting bolt to the cylinder head of the cam chain tensioner is close to the actuator, the relief groove formed in the actuator is used. It is possible to avoid that the tool used for tightening the mounting bolt interferes with the actuator. For this reason, this valve operating mechanism can enable tightening of the mounting bolts of the cam chain tensioner without being hindered by interference with the actuator of the variable valve timing device that is close to the cam chain tensioner. The cam chain tensioner can be attached to a part that is difficult to attach due to interference with the product, which increases the degree of freedom in layout and the tightening position of the mounting bolt is set to a position where interference with the actuator can be avoided. Since there is no need to change it, there is no problem that the tightening balance is impaired and it becomes difficult to secure sufficient mounting strength, there is no need to increase the number of tightening points with mounting bolts, and the number of parts and assembly man-hours are increased. Does not increase.

The engine valve operating mechanism of the present invention is
When tightening the mounting bolts for the cam chain tensioner,
Since the mounting bolt and the escape groove of the actuator of the variable valve timing device need to be aligned with each other, it is possible to confirm whether the mounting position of the actuator of the variable valve timing device is correct. Therefore, this valve mechanism can prevent erroneous assembly of the actuator of the variable valve timing device when tightening the mounting bolt of the cam chain tensioner.

[Brief description of drawings]

FIG. 1 is an enlarged front view of a cylinder head showing a first embodiment of a valve operating mechanism for an engine according to the present invention.

FIG. 2 is a schematic sectional view of an actuator and a cam chain tensioner.

FIG. 3 is a front sectional view of an actuator.

FIG. 4 is a side sectional view of an actuator.

FIG. 5 is a front view of a valve operating mechanism of the engine.

FIG. 6 is a front view of a cylinder head provided with a cam chain tensioner with reduced mounting bolts.

FIG. 7 is a schematic sectional view of an actuator and a cam chain tensioner showing a second embodiment.

FIG. 8 is a schematic sectional view of a cam chain tensioner showing a third embodiment.

FIG. 9 is a front view of a cylinder head showing a conventional example of a valve operating mechanism of an engine.

[Explanation of symbols]

2 engine 4 cylinder block 6A ・ 6B 1st ・ 2nd cylinder head 16 crankshaft 20 Valve mechanism 22A and 22B First and second intake camshafts 24A / 24B First and second exhaust camshafts 26 crank sprockets 28A / 28B First / second intake cam sprocket 30A ・ 30B 1st ・ 2nd exhaust cam sprocket 32A ・ 32B 1st ・ 2nd intermediate sprocket 34 Intermediate shaft 36 Sprocket for the second cam 40 idler sprocket 42 Timing chain 44A 1st cam chain 44B 2nd cam chain 46 Timing Tensioner 48 Timing Chain Guide 50A ・ 50B 1st ・ 2nd cam chain tensioner 62 Variable valve timing device 64A / 64B First / Second Actuator 66A / 66B First / Second Oil Control Valve 68B Second tensioner body 70B pusher 72B / 74B Second cylinder head mounting boss 76B Mounting boss for intermediate shaft 78B / 80B Second cylinder head mounting bolt 82B Intermediate shaft mounting bolt 86B Second rotor 90B Second Vane Chamber 92B Second housing 94B escape groove

Claims (4)

[Claims] 1. A crank sprocket is provided on a crank shaft axially supported by a cylinder block of an engine, and intake and exhaust cam sprockets are provided on intake and exhaust cam shafts axially supported by a cylinder head of the engine, respectively. An intermediate sprocket and a cam sprocket are provided on the intermediate shaft that is attached to the crankshaft, a timing chain is wound around the crank sprocket and the intermediate sprocket, and a cam chain is wound around the intake / exhaust cam sprocket and the cam sprocket. A cam chain tensioner that applies a constant tension to the cam chain is provided, and an actuator of a variable valve timing device that changes the rotational phase with respect to the crankshaft is provided on either one of the intake and exhaust camshafts. In the valve mechanism, the cam The cam chain tensioner is arranged inside the chain line of the chain, and the cam chain tensioner is mounted on the cylinder head by mounting bolts, and the clearance groove for the tool used when tightening the mounting bolts on the outer circumference of the actuator. A valve operating mechanism for an engine, characterized in that the valve operating mechanism is provided. 2. The relief groove is formed and provided at a position facing a tightening position of the mounting bolt of the actuator which is rotated at a specified position of a rotation phase with respect to the crankshaft. 1. The valve operating mechanism of the engine according to 1. 3. The engine valve operating mechanism according to claim 1, wherein the relief groove is formed so as to be located between adjacent vane chambers of the actuator. . 4. The cam chain tensioner is disposed inside the chain line of the cam chain and between any one of the intake / exhaust cam shafts and the intermediate shaft,
2. The cylinder head is mounted by mounting bolts, and is mounted on the cylinder head by mounting bolts together with an intermediate shaft for supporting the intermediate sprocket and the cam sprocket.
The valve operating mechanism of the engine according to.