JP3275774B2 - Engine cam cap 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 cam cap structure of an engine which forms a part of a camshaft bearing of an engine.

[0002]

2. Description of the Related Art Internal combustion engines (engines) for automobiles
In general, an intake port and an exhaust port communicating with a combustion chamber are provided on both sides of a cylinder head, and an intake valve and an exhaust valve are provided at the intake port and the exhaust port, respectively. Therefore, when the engine is driven, the intake and exhaust ports are opened and closed with respect to the combustion chamber by moving the intake and exhaust valves up and down. Then, by driving the intake valve and the exhaust valve, suction of the air-fuel mixture from the intake port into the combustion chamber and discharge of the combustion gas from the combustion chamber to the exhaust port are performed.

The intake valve and the exhaust valve are driven by an intake valve camshaft and an exhaust valve camshaft. FIG. 5 shows a cross section showing a schematic structure of a general DOHC engine.

As shown in FIG. 5, an intake port 3 and an exhaust port 4 communicating with the combustion chamber 2 are provided on both sides of the cylinder head 1, and a communicating portion between the intake port 3 and the exhaust port 4 and the combustion chamber 2 is provided. The front ends of the intake valve 5 and the exhaust valve 6 face. Therefore, when the intake valve 5 and the exhaust valve 6 are driven up and down, the combustion chamber 2 and the intake port 3 and the exhaust port 4 are opened and closed.

A cam chamber 20 is provided in the upper part of the cylinder head 1. In the cam chamber 20, a camshaft 7 for an intake valve and a camshaft 8 for an exhaust valve, which are parallel to each other, are arranged. An intake cam 9 and an exhaust cam 10 each having a predetermined lift amount are integrally formed. The intake valve camshaft 7 and the exhaust valve camshaft 8 are rotatably supported in the respective cam chambers 20 by a plurality of cam caps 11.

Further, rocker arms 12 and 13 are mounted on the cylinder head 1, and the rocker arms 12 and 13 are connected to the lash adjuster 1 by an intake cam 9 and an exhaust cam 10.
It swings around the fulcrum points 4 and 15. The leading ends of the rocker arms 12 and 13 are in contact with the upper ends of the intake valve 5 and the exhaust valve 6, and the rocker arms 12 and 13 can swing to drive the intake valve 5 and the exhaust valve 6 up and down. Reference numeral 16 in the drawing denotes a plug hole for mounting an ignition plug. A rocker cover 24 is provided on the cylinder head 1 so as to cover the upper part of the cam chamber 20.

A cam shaft sprocket (not shown) is fixed to one end of each of the intake valve cam shaft 7 and the exhaust valve cam shaft 8, and a timing belt is looped between each cam shaft sprocket and the crank shaft sprocket. ing. Therefore, each camshaft sprocket rotates in synchronization with the rotation of the crankshaft sprocket, and the intake valve camshaft 7 and the exhaust valve camshaft 8 can be driven to rotate.

[0008]

In the above-described conventional engine, a camshaft 7 for an intake valve and a camshaft 8 for an exhaust valve are provided in a lower semicircular portion for bearing formed on the upper surface of the cylinder head 1. A plurality of cam caps 11 on which the upper semicircular portions for bearings are formed are mounted from above the respective camshafts 7 and 8, and the respective cam caps 11 are fixed to the cylinder head 1 by bolts. . Therefore, the lower semicircular portion of the cylinder head 1 and the upper semicircular portion of the cam cap 11 rotatably support the intake valve camshaft 7 and the exhaust valve camshaft 8.

However, since the intake valve camshaft 7 and the exhaust valve camshaft 8 have predetermined lengths, the respective camshafts 7, 8 are supported by the respective cam caps 11 at a plurality of positions in the long direction. I have. Therefore, there is a problem that the assemblability of the cam cap 11 is not good. In addition, since it is necessary to secure sufficient support rigidity for each of the camshafts 7 and 8, it is necessary to increase the size of the cam cap 11 and the fixing bolt.

Therefore, a plurality of cam caps are integrally connected by a beam or the like to form a frame, and this integral cam cap is fixed to the upper surface of the cylinder head, so that the intake valve cam shaft 7 and the exhaust valve It is considered that the camshaft 8 is rotatably supported.

In a general engine assembly process, a cylinder head is attached to a cylinder block.
With the camshaft for the intake valve and the camshaft for the exhaust valve rotatably supported by the cylinder head and the plurality of cam caps, the camshaft sprocket and the crankshaft sprocket are fixed to one end of each camshaft and the crankshaft, respectively. ing. In order to fix the camshaft sprocket to one end of the camshaft, the camshaft sprocket is fitted to one end of the camshaft and fixed by screwing a nut. In this case, as shown in FIG.
7 are integrally formed, and the tool T is engaged with the hexagonal portion 17 and the tool is also engaged with a nut (not shown). Then, with the nut stopped, turn the tool T
By rotating the camshaft 8 using a screw, the screw portion of the camshaft 8 and the nut are screwed together,
Was connected to a camshaft sprocket.

However, as described above, when an integrated cam cap is used to improve the assemblability of the cam cap and increase the support rigidity, the allowable rotation range of the tool for rotating the cam shaft is restricted. I will. That is, the integral cam cap is provided with side walls on both sides of a cap portion having an upper half portion for supporting the camshaft. When the tool T is engaged with the hexagonal portion of the camshaft, the tool T This side wall is located before and after the rotation direction of T. Therefore, when the camshaft 8 is rotated, the tool T comes into contact with the side wall, and there is a problem that the tool T cannot rotate by a predetermined angle.

In particular, a direct injection type engine in which high-pressure fuel is directly injected into the combustion chamber and intake air is drawn into the combustion chamber from an upright intake port, and the fuel and air are mixed and ignited in the combustion chamber. In this case, a rocker cover is mounted on the upper surface of the integral cam cap, and an intake port is mounted. Therefore, it is necessary to secure a mounting surface for the rocker cover and a mounting surface for the intake port on the upper surface of the integrated cam cap. A flange having a predetermined area is provided at the center of the integrated cam cap. For this reason, it becomes more difficult to insert the tool from above the integrated cam cap, resulting in poor workability.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an engine cam cap which facilitates positioning of a camshaft in a rotating direction and improves workability of assembling a mounting member to the camshaft. The purpose is to provide a structure.

[0015]

In order to achieve the above-mentioned object, in the engine cam cap structure according to the first aspect of the present invention, an upper half portion of the camshaft bearing is formed above the cylinder head. It has an integral cam cap, this
When a pair of side walls are provided on both sides of the
A flange portion is provided at the center, and a pair of side walls and a flange portion are provided.
Camshaft for intake valve and camshaft for exhaust valve
To form a recess with a predetermined width on the camshaft.
Opening on the camshaft side corresponding to the hexagonal part
Is provided . Therefore, by using the concave portion, a tool can be inserted into the integrated cam cap to position the camshaft in the rotational direction, and a mounting member such as a camshaft sprocket connected to the camshaft can be easily formed. Can be assembled.

In the cam cap structure for an engine according to the second aspect of the present invention, the side walls of the integral cam cap have substantially the same thickness along the axial direction of the cam shaft. Therefore, the concave portion can be provided without lowering the strength of the vertical wall, and the strength of the integral cam cap and the cylinder head can be increased.

Further, in the cam cap structure for an engine according to the third aspect of the present invention, the cam cap is mounted above the cylinder head.
Camshaft with the upper half of the
A pair of side walls on both sides of this integral cam cap.
And a flange in the center, and a pair of side walls
For intake valve camshaft and exhaust valve between flanges
Position the camshaft and insert a concave
On the camshaft side corresponding to the hexagon formed in the shaft
It is open and provided on the flange. Therefore, this recess
Use to insert a tool inside the integrated cam cap
Position in the rotation direction of the camshaft.
The camshaft sprocket connected to this camshaft
A mounting member such as a socket can be easily assembled.
In the engine cam cap structure according to the fourth aspect of the present invention,
The part is formed on the lower surface of the flange part. Therefore, franc
Prevents the width of the upper surface of the joint from becoming narrower and secures a sealing surface
it can.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an exploded perspective view of a V-type six-cylinder in-cylinder injection engine showing a cam cap structure of an engine according to an embodiment of the present invention. FIG. 2 is a longitudinal section of a cylinder head portion of the engine. A plan view of the cam cap plate showing the inside of the engine, and FIG. 4 shows a cross section taken along line IV-IV of FIG. 3 showing an engagement state between the tool and the hexagonal portion of the cam shaft.

As shown in FIG. 1, the engine of the present embodiment is a V-type six-cylinder DOHC gasoline engine having three cylinders on one bank, which directly injects high-pressure fuel into a combustion chamber and at the same time through an upright intake port. An in-cylinder injection engine in which intake air is sucked into a combustion chamber and an air-fuel mixture obtained by mixing fuel and air is ignited in the combustion chamber. Each structure shown in FIGS. 2 to 4 is for the cylinder head of the left bank.

As shown in FIG. 1 and FIG.
The pair of right and left bank cylinder heads 33 is fixed to the cylinder block 32, and a cam cap plate 34 as a beam member is fixed to each cylinder head 33. Each cylinder head 33
A camshaft 35 for an intake valve and a camshaft 36 for an exhaust valve, which are parallel to each other, are provided, and are rotatably held by the cam cap plate 34.

The cam sprocket 3 is provided at one axial end of the intake valve camshaft 35 and the exhaust valve camshaft 36.
7, and a crank sprocket 40 is fixed to one end of the crankshaft 39. And
A timing belt 41 is wound around the cam sprockets 37 and 38 and the crank sprocket 40. Accordingly, when the engine 31 operates and the crankshaft 39 rotates, the intake valve camshaft 35 and the exhaust valve camshaft 36 rotate synchronously via the crank sprocket 40, the timing belt 41, and the cam sprockets 37, 38. be able to. The cam sprockets 37 and 38, the crank sprocket 40, and the timing belt 41 are covered with a timing belt cover 70 divided into three parts, respectively.
Is held in close contact with the end face of the rocker cover 42 fixed to the cam cap plate 34.

On the upper surface of the cam cap plate 34, a rocker cover 42 is floatingly supported via a seal member 63, and the rocker cover 42 is provided with an outlet 43 for blow-by gas. That is, the upper space of the cylinder head 33 formed between the cylinder head 33, the cam cap plate 34, and the rocker cover 42
And can be connected to the intake system via the. Therefore, the blow-by gas leaked into the cylinder block 32 is sent from the outlet 43 to the intake system through the upper space of the cylinder head 33, mixed with fresh air, and flows into the combustion chamber again, thereby enabling combustion. ing.

An intake port 45 and an exhaust port 46 are connected to a combustion chamber 44 formed in the cylinder head 33, and the combustion chamber 44 of the intake port 45 and the exhaust port 46 is connected.
The leading ends of the intake valve 47 and the exhaust valve 48 face the communicating portion with. Therefore, by driving the intake valve 47 and the exhaust valve 48 up and down, the combustion chamber 44 and the intake port 45 and the exhaust port 46 are opened and closed. The intake port 45 stands upright and opens to the intake hole 53 in the central portion 56 of the cam cap plate 34, and the exhaust port 46 opens to the side of the cylinder head 33. A flange 55 of an intake manifold 54 is rigidly connected to an upper surface of a central portion 56 of the cam cap plate 34 via a gasket 91, and the intake manifold 54 communicates with an intake hole 53.

An intake cam chamber 49 and an exhaust cam chamber 50 are formed independently on both sides of the cam cap plate 34 with the central portion 56 interposed therebetween. The intake valve camshaft 35 and the exhaust valve camshaft 36 are provided. The intake valve camshaft 35 and the exhaust valve camshaft 36 are integrally formed with an intake cam 51 and an exhaust cam 52 having a predetermined lift amount for each cylinder.

The cylinder head 33 has a rocker arm 5
The rocker arms 57, 58 are pivoted about the lash adjusters 59, 60 by the intake cam 51 and the exhaust cam 52.
The tip of the rocker arms 57 and 58 is connected to the intake valve 4.
When the rocker arms 57 and 58 swing in contact with the upper ends of the exhaust valve 48 and the exhaust valve 48, the intake valve 47 and the exhaust valve 48 can be driven up and down.

Here, the cam cap plate 34 will be described in detail. As shown in FIGS. 2 and 3, the cam cap plate 34 has a frame shape and has a cylinder head 22.
A plurality of cap portions 61 fixed to the upper side and integrally provided in the respective cam chambers 49 and 50 are provided with respective camshafts 35 and
The camshafts 35 and 36 can be rotatably supported by being fixed to the support portion of the cylinder head 33 with the 36 interposed therebetween. A plug mounting hole 62 for mounting a spark plug and a pair of intake holes 53 are provided in the central portion 56 of the cam cap plate 34 for each cylinder, and the intake manifold 54 is provided in the central portion 56 as described above.
Is fixed, the intake manifold 54 is connected to the intake hole 5.
3, and is connected to the intake port 45.

On the upper surface of the cam cap plate 34, a rocker cover 42 is floatingly supported via a seal member 63. That is, the rocker cover 42 is floatingly supported on the cam cap plate 34 on the main body side of the engine 31, and the intake manifold 54 is rigidly connected through the center of the rocker cover 42.

The intake cam chamber 49 of the cam cap plate 34 has a predetermined width in the axial direction at the central portion 56 on one side wall and the other side in the axial direction of the intake valve camshaft 35. Recesses 81, 8 opening on the camshaft 35 side
2 are provided. That is, each of the intake valve camshaft 35 and the exhaust valve camshaft 36 has
Hexagonal portions 83 and 84 are formed, and the intake cam chamber 4
Recesses 81 and 82 having a width slightly larger than the thickness of the tool 85 are provided at positions corresponding to the hexagonal portions 83 on the ninth side. As shown in FIG. 4, the recesses 81 and 82 allow a tool 85 to be inserted into the intake cam chamber 49 of the cam cap plate 34, and allow a predetermined angle of rotation while the tool is engaged with the hexagonal portion 83. It is for doing. for that reason,
The concave portion 81 is formed by expanding the side wall 86 of the cam cap plate 34 outward only by that portion, and has substantially the same thickness along the axial direction of the camshaft 35. That is, by making the side wall thickness the same, the side wall strength is improved, and the width of the sealing surface with the rocker cover 42 that covers the upper surface of the cam cap plate 34 can be secured. Further, the concave portion 82 is formed by cutting out the lower surface of the flange portion 87 of the central portion 56 of the cam cap plate 34 so that the width of the upper surface of the flange portion 87 is not narrowed, and the concave portion 82 is formed with the sealing surface of the seal member 63 of the rocker cover 42. The seal surface of the gasket 91 of the intake manifold 54 is secured.

Therefore, as shown in FIG. 4 (a), the tool 85 can be inserted into the intake cam chamber 49 from above the cam cap plate 34 by the concave portions 81 and 82 of the cam cap plate 34, and the cam can be easily formed. It can be engaged with the hexagonal portion 83 of the shaft 35. Also, as shown in FIG. 3, the camshaft sprocket 37 is fitted to one end of the camshaft 35 and a nut 88 is screwed into the camshaft 35, and the nut 88 is prevented from rotating by a tool (not shown). As shown in (), when the tool 85 engaged with the hexagonal portion 83 is rotated, a large permissible rotation angle of the tool 85 can be secured by the concave portions 81 and 82.

As described above, in the cam cap structure of the engine according to the present embodiment, the recesses 81, 81 are formed in the side wall 86 and the flange 87 of the intake cam chamber 49 of the cam cap plate 34.
By providing the camshaft 35, the tool 85 can be easily inserted into the intake cam chamber 49 from above the cam cap plate 34 by using the recesses 81 and 82.
Can be engaged with the hexagonal portion 83 of the camshaft, and a large permissible rotation angle of the tool 85 is secured by the concave portions 81 and 82. The camshaft sprocket 37 is fitted to one end of the camshaft 35. Nut 8
By rotating the tool 85 in a state where the nut 8 is screwed and the nut 88 is prevented from rotating by the tool, the camshaft sprocket 37 can be easily connected.

In the cam cap structure of the engine according to the present embodiment, the side wall 86 of the cam cap plate 34 has substantially the same thickness along the axial direction of the camshaft 35 even if the recess 81 is formed. 34
The strength of the cover does not decrease and the low or cover 42
Seal surface can be secured. Further, by forming the concave portion 82 by cutting out the lower surface of the flange portion 87 of the cam cap plate 34, the width of the upper surface of the flange portion 87 does not become narrow, and the rocker cover 42 and the intake manifold 5
4 seal surface can be secured. The hexagonal portion 83 of the intake valve camshaft 35 is provided on the cam cap plate 34.
By providing the concave portions 81 and 82 corresponding to the above, the engagement between the tool 85 and the hexagonal portion 83 becomes easy. The hexagonal portion 83 and the concave portions 81 and 82 of the intake valve camshaft 35 may be displaced in the axial direction of the camshaft 35 as long as the tool 85 can be easily attached and detached.

As an engine to which the above-described cam cap structure of the engine of the present invention is applied, as in the above-described embodiment, high-pressure fuel is directly injected into the combustion chamber, and the intake air sucked from the intake port and the internal combustion chamber are used. It is not limited to the direct injection type V6 cylinder DOHC engine that mixes and ignites the air-fuel mixture. The intake port and the exhaust port are opened to the side of the cylinder head to inject fuel into the intake passage. It is also possible to apply to an engine. Further, the state of the cylinder is not limited to the V-type six-cylinder, but may be applied to an engine other than the above-described embodiment, such as an in-line six-cylinder or an in-line four-cylinder engine.

[0034]

As described above in detail in the embodiment, according to the cam cap structure of the engine of the first aspect, the upper half of the camshaft bearing is formed by being placed above the cylinder head. Yes an integral cam cap
Then, a pair of side walls are provided on both sides of this integrated cam cap.
And a flange in the center, a pair of side walls and a flange
Camshaft for intake valve and camshaft for exhaust valve
Position the shaft and fit the camshaft
Opening on the camshaft side corresponding to the hexagon formed in
Te so provided in the side wall, by using the concave portion, it is possible to position the rotating direction of the cam shaft to facilitate insertion of the tool into the interior of the integral cam cap, such as a camshaft sprocket of binding to the camshaft Can easily be assembled in a short time, and as a result, the workability of assembling the mounting member to the camshaft can be improved.

According to the cam cap structure for an engine of the second aspect of the present invention, the side walls of the integral cam cap have substantially the same thickness in the axial direction of the cam shaft.
The concave portion can be provided without lowering the strength of the vertical wall, and the strength of the integral cam cap and the cylinder head can be improved.

According to the third aspect of the present invention, the engine cam cap structure is mounted above the cylinder head.
Integrated camshaft with the upper half of the camshaft bearing
With a pair of cam caps on both sides of this integral cam cap.
Provide a side wall and a flange at the center,
Camshaft for intake valve and exhaust between wall and flange
Position the valve camshaft and close the recess with the specified width.
Camshaft corresponding to the hexagonal section formed on the camshaft
Since it is open on the side and provided on the flange,
And easily insert the tool inside the integrated cam cap
Position in the rotation direction of the camshaft.
The camshaft sprocket connected to this camshaft
Can easily and quickly mount mounting members such as
it can. As a result, the attachment of the mounting member to the camshaft
The workability can be improved. Further, according to the cam cap structure of the engine of the invention of claim 4, the concave portion is formed by a flank.
Because it is formed on the lower surface of the flange, the width of the upper surface of the flange is narrow.
It is possible to secure the sealing surface while preventing the occurrence of the sealing.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a V-type six-cylinder direct injection engine showing a cam cap structure of an engine according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a cylinder head portion of the engine.

FIG. 3 is a plan view of a cam cap plate showing the inside of the engine.

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3 showing an engagement state between the tool and a hexagonal portion of the camshaft.

FIG. 5 is a cross-sectional view illustrating a schematic structure of a general DOHC engine.

[Explanation of symbols]

Reference Signs List 31 engine 33 cylinder head 34 cam cap plate 35 camshaft for intake valve 36 camshaft for exhaust valve 42 rocker cover 49 intake cam chamber 50 exhaust cam chamber 53 intake hole 54 intake manifold 56 central part 61 cam cap part 62 plug mounting hole 63 Sealing member 70 Timing belt cover 81, 82 Recess 83, 84 Hexagonal part 85 Tool 86 Side wall 87 Flange part 88 Nut 91 Gasket

Claims (4)

(57) [Claims] 1. A cylinder head mounted above a cylinder block of an engine and having a lower half of a camshaft bearing formed on an upper surface thereof, and a camshaft mounted above the cylinder head and formed on a lower surface thereof. comprising an integral cam cap upper half of the bearing is formed, the integrated cam
The cap is a pair of caps on both sides in the axial direction of the camshaft.
A side wall is provided, and the center of the pair of side walls is
A flange portion is provided along the axis of the shaft.
A camshaft for an intake valve between a pair of side walls and the flange portion
And a camshaft for the exhaust valve,
The camshaft has a recess having a predetermined width in the axial direction of the shaft.
Opening on the camshaft side corresponding to the hexagon formed in
Cam cap structure for an engine, characterized in that provided in the side walls and. 2. A cam cap structure for an engine according to claim 1, wherein a side wall of said integral cam cap has substantially the same thickness along an axial direction of said cam shaft. . 3. An engine mounted above an engine cylinder block.
And the lower half of the camshaft bearing is formed on the upper surface
And the cylinder head mounted above the cylinder head
And the upper half of the camshaft bearing on the lower surface.
And a formed integral cam cap.
The cap is a pair of caps on both sides in the axial direction of the camshaft.
A side wall is provided, and the center of the pair of side walls is
A flange portion is provided along the axis of the shaft.
A camshaft for an intake valve between a pair of side walls and the flange portion
And a camshaft for the exhaust valve,
The camshaft has a recess having a predetermined width in the axial direction of the shaft.
Opening on the camshaft side corresponding to the hexagon formed in
Cam cap structure for an engine, characterized in that provided in the flange portion by. 4. A cam cap for an engine according to claim 3.
In the structure, the concave portion is formed on a lower surface of the flange portion.
A cam cap structure for an engine.