JP3263118B2 - Engine cylinder head structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head structure for an engine, and more particularly to a cylinder head structure for an engine in which a camshaft drives a suction valve and an exhaust valve via a rocker arm.

[0002]

2. Description of the Related Art In an engine in which intake and exhaust valves are driven by a camshaft via a rocker arm, a clearance between the intake and exhaust valves or the camshaft and the rocker arm (hereinafter referred to as valve clearance). It is necessary to appropriately adjust
Japanese Patent Application Publication No. 06-2006 discloses that a base end portion of a rocker arm having a distal end portion abutting on a valve shaft head is swingably supported by an eccentric bush rotatably fitted to a rocker arm shaft while being eccentric to the rocker arm shaft. At the same time, a hydraulic clearance adjusting mechanism (hereinafter, referred to as HLA) having a plunger that protrudes and retracts by hydraulic pressure is disposed at a position lateral to the camshaft direction with respect to the rocker arm shaft. A configuration is shown in which the plunger is disposed so as to be in contact with a receiving portion extending in the direction. According to this, the eccentric push pivots on the rocker arm shaft as an axis in balance with the pressing force of the plunger acting via the receiving portion, so that the support position of the rocker arm changes, and the rocker arm becomes a valve. The state is automatically adjusted to a zero rush state in which the shaft head and the camshaft are in close contact with each other.

[0003]

However, in the prior art described in the above-mentioned publication, an HLA for changing the support position of the rocker arm is provided on the cylinder head. Therefore, there is a problem that the design of the cylinder head needs to be changed in order to supply, and the production cost increases. Moreover,
Since the HLA is disposed on the opposite side of the camshaft with respect to the rocker arm shaft, there is a problem that the size of the engine in the width direction is increased.

The present invention addresses the above-described problem in an engine in which a camshaft drives an intake and exhaust valve through a rocker arm, and adjusts valve clearance by changing the support position of the rocker arm. Adjustment means for installing the cylinder head without changing the structure of the cylinder head.

[0005]

That is, a cylinder head structure for an engine according to the invention of claim 1 of the present application (hereinafter referred to as a first invention) drives a suction and exhaust valve by a camshaft via a rocker arm. In the engine, a rocker arm shaft is eccentrically mounted on an eccentric member which is rotatably fitted to the rocker arm shaft. The bearing member for supporting the shaft is connected by a connecting member arranged along the direction in which the camshaft is disposed, and the connecting member is provided with adjusting means for rotating the eccentric member to change the support position of the rocker arm. And lock
Arrange the camshaft above the car arm and
A connecting member is arranged above the rocker arm shaft, and
The connecting member is provided with the adjusting means, and the shaft of the eccentric member is further provided.
That project from the side of the camshaft toward the camshaft
A part is provided, and the adjusting means is in contact with the upper surface side of the receiving part .

[0006]

The invention of claim 2 of the present application (hereinafter referred to as the
In the cylinder head structure for an engine according to the second aspect of the invention, the adjusting means of the first aspect of the invention is threadably engaged with the connecting member such that the distal end thereof is in contact with the receiving portion provided on the eccentric member. and the adjustment screw, while composed of a screwed lock nut on the adjustment screw, characterized by being arranged toward the operating portion of the adjusting screw upwards.

On the other hand, the invention of claim 3 of the present application (hereinafter referred to as third invention)
The cylinder head structure of the engine according to the invention)
Wherein the adjusting means in the first shot bright, while adopting the hydraulic clearance adjusting mechanism having a plunger which operates forward and backward by oil pressure, that the mechanism is arranged so that the plunger is in contact against the Uketamawatome portion of the eccentric member And

The invention of claim 4 of the present application (hereinafter referred to as the
An engine cylinder head structure according to a fourth aspect of the invention is characterized in that the connecting member according to the first to third aspects is provided between the cylinder head and the separated lower bearing member.

Further, the invention of claim 5 of the present application (hereinafter referred to as the
According to a fifth aspect of the present invention, there is provided a cylinder head structure for an engine, wherein a lower bearing member separated from the cylinder head according to the fourth aspect is provided in an engine having three or more intake valves or exhaust valves per cylinder. I do.

[0011]

According to the above construction, in any of the first to fifth aspects of the invention, the rocker supported by the eccentric member is rotated by rotating the eccentric member rotatably fitted to the rocker arm shaft. Since the adjusting means for changing the support position of the arm is provided on the connecting member for connecting the bearing member of the camshaft, it is possible to install this kind of adjusting means without particularly changing the structure of the cylinder head. As a result, the structure is simplified, and the rigidity of the bearing member supporting the camshaft is also improved.

According to the first aspect of the present invention, the connecting member for connecting the bearing member is arranged above the rocker arm shaft provided with the eccentric member, and the connecting member is provided with the adjusting means. The means can be installed compactly. In addition, since the camshaft is arranged above the rocker arm, an end pivot type rocker arm can be employed, and there is a benefit that the valve train is lightened.

According to the second aspect of the present invention, since the connecting member is disposed above the rocker arm shaft, and the adjusting screw is attached to the connecting member with the operation portion facing upward, the manual operation is performed. There is an advantage that the adjustment operation can be easily performed.

According to the third aspect of the present invention, since the hydraulic gap adjusting mechanism having the plunger which moves forward and backward by hydraulic pressure is used as the adjusting means, the work of adjusting the support position of the rocker arm by rotating the eccentric member is performed. Will be automated.

According to the fourth aspect , since the connecting member is provided on the lower bearing member separated from the cylinder head, the rigidity of the bearing member is improved.

Further, according to the fifth invention, in an engine having three or more intake valves or exhaust valves per cylinder, a lower bearing member separated from a cylinder head is provided, and the lower bearing member is connected to a camshaft. By connecting via a connecting member along the disposition direction, even when the support portion of the camshaft cannot be provided integrally with the cylinder head, the adjusting means can be made compact while securing the bearing rigidity of the camshaft. Can be installed.

[0017]

Embodiments of the present invention will be described below.

As shown in FIGS. 1 and 2, the engine 1 has a cylinder block 2 in which a plurality of cylinder bores 5 are arranged in a row, and a cylinder head 3 installed above the block 2. The head 3 is on both sides
A piston fixed to the cylinder block 2 via a head bolt 4 screwed into the cylinder block 2 from above, and an inner peripheral surface of the cylinder bore 5 in the cylinder block 2 and a piston slidably inserted in the cylinder bore 5. A combustion chamber 7 is defined by an upper surface of the cylinder 6 and a ceiling recessed above the cylinder head 3. The cylinder head 3 is provided with an intake port 8 communicating from one side to the combustion chamber 7 and an exhaust port 9 communicating from the other side to the combustion chamber 7. 9 are provided with intake and exhaust valves 10 and 11 for opening and closing an opening to the ceiling surface of the combustion chamber. Of these, the intake valve 10
As shown in FIG. 2, three cylinders are provided for each cylinder along the cylinder row direction. Although not shown, two exhaust valves 11 are provided for each cylinder along the cylinder row direction.

Then, as shown in FIG.
0, a valve shaft 10 that is connected to the valve body 10a and extends upward.
b, and a spring retainer 12 is provided near the valve shaft head 10c penetrating the cylinder head 3, and a valve spring 13 is interposed between the retainer 12 and the upper surface of the cylinder head. ing. Also,
The exhaust valve 11 also has an upwardly extending valve shaft 11b connected to the valve body 11a.
A spring retainer 12 is provided in the vicinity of the valve shaft head 11c that penetrates the valve shaft, and a valve spring 13 is interposed between the retainer 12 and the upper surface of the cylinder head.

On the other hand, first and second camshafts 15 and 16 are arranged above the cylinder head 3 inside the rocker cover 14 at positions corresponding to the intake and exhaust valves 10 and 11.

Among them, the first camshaft 15 is provided on a lower bearing member 17 erected between the left and right support walls 3a, 3b erected on the upper surface of the cylinder head and on the upper surface thereof. The flanges 1 at both ends of the cam cap 18 are supported by a bearing with the cam cap 18.
8a, 18b from above through the support walls 3a, 3b
The lower bearing member 17 is mounted together with the cam cap 18 on the cylinder head 3 by the mounting bolts 19 and 19 screwed to the cylinder head 3.
It is fixed to.

Here, as shown in FIG. 2, the head bolts 4 are arranged in the cylinder row direction so as to avoid the cylinder bores 5. On both sides of the head bolts 4, allowances for inserting and removing the head bolts 4 are provided. The supporting walls 3a and 3b are provided to support the lower bearing member 17 or the cam cap 18 in a state where the lower bearing member 17 or the cam cap 18 is in the extended state. That is, when the first camshaft 15 is mounted, it is mounted in the following procedure.

First, the head bolt 4 is connected to the cylinder head 3
, And screwed into the cylinder block 2, and the lower bearing member 17 is placed on the support walls 3 a and 3 b from above. Next, the first camshaft 15 is connected to the lower bearing member 17.
The two mounting bolts 19, 19 are inserted between the flanges 18a, 18b at both ends of the cam cap 18 and the lower bearing member 17 so that the support walls 3a, 3b Into each screw.
Thereby, the cam cap 18 or the lower bearing member 17
Are integrated with the cylinder head 3.

As shown in FIGS. 3 and 4, a first rocker arm shaft 20 is disposed in parallel below the first camshaft 15 on the side opposite to the center of the combustion chamber. The eccentric bush 22 that swingably supports the cylindrical base end 21a of the intake rocker arm 21 provided corresponding to the first rocker arm shaft 2
It is rotatably fitted outside in a state eccentric to zero. As shown in FIG. 4, the intake rocker arm 21 is provided with an opening 23 in an arm 21 b extending from a cylindrical base end 21 a externally fitted to the eccentric bush 22. 2
3 is rotatably supported via a pin 25, and a contact end 21c which is in contact with the valve shaft head 10c of the intake valve 10 is provided at the tip of the arm 21b in a bent manner. Have been. Each of the intake rocker arms 21 is disposed below the first camshaft 15, and the roller 24 supported by the arm portion 21 b is connected to the first camshaft 15.
And the lower end of the same number of intake cams 26 provided at the front end, and a contact end portion 21c on the distal end side is connected to the valve shaft head 10 of the intake valve 10.
c.

On the other hand, the first rocker arm shaft 2
A connecting member 27 for connecting an end of the lower bearing member 17 on the opposite side of the center of the non-combustion chamber is provided above the first camshaft 15.
The connecting member 27 has a boss 27a at a position corresponding to the intake rocker arm 21.
Is formed, and an adjusting screw 28 is screwed to each boss portion 27a so as to be able to advance and retreat. As shown in FIG. 3, the adjusting screw 28 is connected to the boss 27a.
Is disposed in an inclined state, and the tip thereof is disposed in contact with a stopper 22 a protruding to the side of the eccentric bush 22, and an operating part 28 provided at the upper end thereof
A has a minus groove 29 formed therein. A lock nut 30 is screwed in the vicinity of the operation section 28a.

The ends of the lower bearing members 17 on the center side of the combustion chamber are also connected to each other via a connecting member 31 arranged along the first camshaft 15.

On the other hand, the second camshaft 16 also corresponds to FIG.
As shown in FIG. 7, the bearing is supported by a lower bearing member 32 installed between the left and right support walls 3c and 3d erected on the upper surface of the cylinder head and a cam cap 33 installed on the upper surface thereof. At the same time, the mounting bolts 19, 19 which penetrate through the flange portions 33a, 33b at both ends of the cam cap 33 from above and are screwed to the support walls 3c, 3d.
Thereby, the lower bearing member 32 is fixed to the cylinder head 3 together with the cam cap 33.

A second rocker arm shaft 34 is arranged in parallel below the second camshaft 16 at the center of the combustion chamber. Also in this case, each exhaust valve 11
The eccentric bush 22 that swingably supports the base end side of the exhaust rocker arm 35 provided corresponding to
The rocker arm shaft 34 is rotatably fitted to the rocker arm shaft 34 in an eccentric state. And each rocker arm 3 for exhaust
5 is disposed below the second camshaft 16, and a roller 24 supported at an intermediate portion of the second camshaft 16 is
6 are in contact with the lower surfaces of the same number of exhaust cams 36 provided in the same.

The second rocker arm shaft 3
A connecting member 37 for connecting an end of the lower bearing member 32 on the center side of the combustion chamber is disposed along the second camshaft 16 above the lower bearing member 32, and an adjusting screw 28 is connected to the connecting member 37. It is screwed forward and backward freely.
In addition, the end of the lower bearing member 32 on the opposite side to the center of the combustion chamber is also connected to each other via a connecting member 38 arranged along the second camshaft 16.

According to such a configuration, for example, as shown in FIG. 5, when the valve clearance on the intake valve side becomes excessive, the valve clearance is adjusted in the following procedure.

That is, after the lock nut 30 screwed to the adjustment screw 28 is loosened, a clearance gauge 39 is inserted between the valve shaft head 10c of the intake valve 10 and the intake rocker arm 21, for example. Then, for example, a minus screwdriver is fitted into the minus groove 30 of the operation section 28a, and the adjustment screw 28 is rotated clockwise. Then, the adjusting screw 28 moves downward, and accordingly, the eccentric bush 22 rotates clockwise about the first rocker arm shaft 20 as an axis. Therefore, the cylindrical base end 21 a of the intake rocker arm 21 fitted to the eccentric bush 22 rotates upward with the contact end 21 c contacting the gap gauge 39 as a fulcrum. Then, as shown by a chain line in the figure, when the roller 24 comes into contact with the intake cam 26, the lock nut 30 is tightened, and the adjustment operation is completed.

Of course, for the exhaust valve 11, the same operation is performed to adjust the valve clearance.

Next, a second embodiment of the present invention will be described with reference to FIG.

That is, in this embodiment, a connecting member 40 for connecting the flange portion 18a at one end of the cam cap 18 is provided above the first rocker arm shaft 20 supporting the intake rocker arm 21. 15 are arranged. And this connecting member 4
0, a boss 40a is provided at a position corresponding to the intake valve 10, and a plunger 41 is provided on the boss 40a.
The HLA 42 is incorporated so as to be in contact with the receiving portion 22a provided in the HLA 2. An oil passage 45 is formed between an oil gallery 43 formed on the connecting member 40 and an oil chamber 44 formed on the back of the HLA 42.

The flange 18b on the other end of the cam cap 18 is also connected to each other via a connecting member 46 arranged along the first camshaft 15.

According to such a configuration, when a gap is formed between the intake rocker arm 21 and the intake cam 26, the plunger 41 of the HLA 42 protrudes to rotate the eccentric bush 22 to rotate the rocker arm. 21 is raised, and the roller 2 of the arm 21 is raised.
4 is brought into contact with the intake cam 26 to automatically adjust the state to zero rush.

Of course, an HLA may be installed by providing a connecting member for connecting the lower bearing member 17.

[0038]

As described above, according to the present invention, the supporting position of the rocker arm supported by the eccentric member is changed by rotating the eccentric member rotatably fitted on the rocker arm shaft. Since the adjusting means is provided on the connecting member for connecting the bearing member of the camshaft, this kind of adjusting means can be installed without particularly changing the structure of the cylinder head, and the configuration is simplified. In addition, the rigidity of the bearing member that supports the camshaft is improved.

According to the first aspect of the present invention, the connecting member for connecting the bearing member is disposed above the rocker arm shaft provided with the eccentric member, and the connecting member is provided with the adjusting means. The means can be installed compactly. In addition, since the camshaft is arranged above the rocker arm, an end pivot type rocker arm can be employed, and there is a benefit that the valve train is lightened.

According to the second aspect of the present invention, since the connecting member is disposed above the rocker arm shaft, and the adjusting screw is attached to the connecting member with the operation portion facing upward, the manual operation is performed. There is an advantage that the adjustment operation can be easily performed.

According to the third aspect of the present invention, since the hydraulic gap adjusting mechanism having the plunger which moves forward and backward by hydraulic pressure is used as the adjusting means, the work of adjusting the support position of the rocker arm by rotating the eccentric member is performed. Will be automated.

According to the fourth aspect of the invention, since the connecting member is provided on the lower bearing member separated from the cylinder head, the rigidity of the bearing member is improved.

Further, according to the fifth invention, in an engine having three or more intake valves or exhaust valves for one cylinder, a lower bearing member separated from a cylinder head is provided, and the lower bearing member is connected to a camshaft. By connecting via a connecting member along the disposition direction, even when the support portion of the camshaft cannot be provided integrally with the cylinder head, the adjusting means can be made compact while securing the bearing rigidity of the camshaft. Can be installed.

[Brief description of the drawings]

FIG. 1 is a sectional view of an upper part of an engine showing a first embodiment.

FIG. 2 is a partial plan view of the engine with a rocker cover removed.

FIG. 3 is a sectional view of an essential part taken along line AA of FIG. 2;

FIG. 4 is a fragmentary sectional view showing a part of the intake rocker arm cut away.

FIG. 5 is a schematic view showing the operation of the first embodiment.

FIG. 6 is a sectional view of a main part showing a second embodiment.

[Explanation of symbols]

 Reference Signs List 3 Cylinder head 10 Intake valve 11 Exhaust valve 15 First camshaft 17 Lower bearing member 18 Cam cap 20 First rocker arm shaft 21 Intake rocker arm 22 Eccentric bush 27 Connection member 28 Adjust screw 28a Operation unit 30 Lock nut 40 Connection Member 41 Plunger 42 HLA

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-96406 (JP, A) JP-A-1-71107 (JP, U) JP-B 64-1645 (JP, B1) JP-B-3 11361 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 1/20 F01L 1/18 F01L 1/26 F02F 1/24

Claims (5)

(57) [Claims] 1. An engine cylinder head structure in which a camshaft drives a suction and exhaust valve via a rocker arm, wherein the eccentric member is rotatably fitted to the rocker arm shaft so as to be rotatably fitted to the rocker arm shaft. The rocker arm has a base end portion swingably supported, and a bearing member for supporting a camshaft disposed above the cylinder head is connected by a connecting member disposed along the direction in which the shaft is disposed. Adjusting means for rotating the eccentric member to change the support position of the rocker arm, and disposing a camshaft above the rocker arm.
And a connecting member above the rocker arm shaft.
And the connecting member is provided with the adjusting means,
To the camshaft from the axial side of the eccentric member
The stopper is provided with a protruding part.
The cylinder head structure of the engine, wherein the adjusting means is in contact with the engine. 2. An eccentric member having a tip end provided on the eccentric member.
Threaded to the connecting member so that it can move back and forth while contacting the
Adjusting screw and the adjusting screw
And a lock nut screwed into the
The operating part of the adjustment screw is arranged upward
The engine cylinder according to claim 2, characterized in that:
Head structure. 3. A push-pull device for moving the adjusting means back and forth by hydraulic pressure.
A hydraulic clearance adjusting mechanism having a lancer,
Set the plunger so that the plunger contacts the receiving part of the eccentric member.
3. The device according to claim 1, wherein
The cylinder head structure for an engine according to any one of the above. 4. The connecting member is separated from the cylinder head.
2. The method according to claim 1, wherein the lower bearing member is provided between the lower bearing members.
The cylinder head of the engine according to claim 4.
Do structure. 5. A lower bearing member separated from a cylinder head.
And three or more intake or exhaust valves per cylinder
The engine according to claim 5, wherein the engine is provided.
Engine cylinder head structure.