JP3275773B2 - 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. 7 shows a cross section showing a schematic structure of a general DOHC engine.

As shown in FIG. 7, 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 section 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, a cylinder head is mounted on an upper portion of a cylinder block. A camshaft for an intake valve and a camshaft for an exhaust valve are mounted on an upper surface of the cylinder head. Is fixed, and a rocker cover is further fixed on the cam cap. In such an engine assembling process, a cylinder head assembly having a camshaft, a valve, and the like mounted thereon is generally mounted on a cylinder block assembly having a crankshaft, a piston, and the like mounted thereon. The two were fixed by inserting a tool from above the assembly and fastening the fixing bolts, and finally the rocker cover was attached.

However, as described above, when an integral cam cap is used to improve the assemblability of the cam cap and to increase the support rigidity, the cylinder head assembly has a state in which the integral cam cap is fixed on the upper part. With this, it is fixed to the cylinder block assembly. In this case, a tool is inserted from above the cylinder head assembly to fasten the fixing bolts. However, since the integral cam cap occupies a large space above the cylinder head as compared with the conventional cam cap, this ratio is large. There is a problem that a tool cannot be inserted from above to the fixing bolt because the integral cam cap is in the way.

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 the mounting seal surface of the rocker cover and the mounting seal surface of the intake port on the upper surface of the integrated cam cap, and this integrated cam cap closes the upper space of the cylinder head. The fixing bolt tool could not be inserted from above the integrated cam cap. Therefore, conventionally, the cylinder head is fixed to the cylinder block, and then the camshaft is mounted on the upper surface of the cylinder head, and then the integral cam cap is attached to the cylinder head, so that the assembling workability is not good. Was.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a cam cap structure of an engine in which the workability of assembling a cylinder block and a cylinder head is improved.

[0015]

To achieve the above object, according to an aspect of, the cam cap structure of the engine of the invention of claim 1, on both sides of the central portion of the integrated cam cap that is fixed above the cylinder head, the cylinder An insertion portion for a first fixing member for fixing the head to the cylinder block is provided, and an integral cam cap is provided around the insertion portion.
Notches are provided on both side surfaces at the center of the . Therefore, when the cylinder head to which the integral cam cap is fixed is fixed to the cylinder block, a tool can be inserted into the cylinder head from the notch of the insertion portion to operate the first fixing member, and the cylinder with respect to the cylinder block can be operated. The head can be easily mounted.

In the engine cam cap structure according to the second aspect of the present invention, a plurality of ports are fastened to the upper surface of the central portion of the integral cam cap along the axial direction of the cam shaft via a gasket. The notch is provided at a position corresponding to between the ports in the axial direction of the camshaft. Therefore, the notch can be formed without affecting the sealing performance of the gasket of the plurality of ports .

[0017]

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. 4 shows a plan view of a cam cap plate showing the inside of the engine, FIG. 4 shows a plan view of a rocker cover, FIG. 5 shows a plan view of a seal member, and FIG. 6 shows a vertical cross section of a cylinder head showing a mounted state of the cylinder head.

As shown in FIG. 1, the engine of the present embodiment is a V-type 6-cylinder DOHC gasoline engine having three cylinders on one bank, which directly injects high-pressure fuel into a combustion chamber and also has an intake port which stands upright. 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 of the structures shown in FIGS. 2 to 6 is for the cylinder head of the left bank.

As shown in FIG. 1 and FIG.
The pair of cylinder heads 33 on the right bank side and the left bank side are fixed to the cylinder block 32 by a plurality of fixing bolts 81 (see FIG. 6) as first fixing members, respectively. Is fixed. An intake valve camshaft 35 and an exhaust valve camshaft 36, which are parallel to each other, are provided on each cylinder head 33, respectively.
The cam cap plate 34 is rotatably held.

A cam sprocket 3 is provided at one axial end of each 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.

A rocker cover 42 is floatingly supported on the upper surface of the cam cap plate 34 via a seal member 63. The rocker cover 42 is provided with a blow-by gas outlet 43. 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 to the combustion chamber 44.
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 rocker arm 5 is mounted on the cylinder head 33.
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 fixing bolts 82 and 83 as second fixing members with the 36 interposed therebetween. And this cam cap plate 3
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 each cylinder for each cylinder, and the intake manifold 54 is fixed to the central portion 56 as described above. The intake manifold 54 has an intake hole 53
Through 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.

A plurality of insertion portions 84 for fixing bolts 81 are provided in the intake cam chamber 49 and the exhaust cam chamber 50 of the cam cap plate 34. This insertion portion 84
Is a tool 8 for rotating the fixing bolt 81 from above the cam cap plate 34 when the cylinder head 33 is fixed to the cylinder block 32 by the fixing bolt 81.
5 is to be inserted. Accordingly, each of the insertion portions 84 is provided on both sides of the central portion 56 of the cam cap plate 34 so as to correspond to the position of the fixing bolt 81, so that the tool 85 can be easily inserted to the lower portion of the cylinder head 33. Notches 86 are formed in the peripheral portion of each insertion portion 84, that is, on both wall surfaces of the central portion 56 of the cam cap plate 34.

The insertion section 84 on the intake cam chamber 49 side and the insertion section 84 on the exhaust cam chamber 50 side are connected to the camshaft 3.
5, 36 are located on a straight line along the horizontal direction orthogonal to the axial direction. Further, the insertion portion 84 (notch portion 86)
Are arranged side by side in the axial direction of the camshafts 35 and 36, and their positions are provided corresponding to the respective ports formed by the respective intake manifolds 54. for that reason,
Insert each insertion portion 84 (notch portion 86) into the cam cap plate 3
4 on the side wall of the central portion 56,
, That is, the mounting surface of the intake manifold 54 becomes narrower.
Since the gasket 91 is located between the intake manifolds 54 in the axial direction of FIG. In this manner, the insertion portion 84 (the cutout portion 86) can be provided without impairing the connection sealing property between the intake manifold 54 and the cam cap plate 34 by the gasket 91.

Next, the rocker cover 42 and the sealing member 6
3 will be described in detail. As shown in FIGS. 1 and 4, the rocker cover 42 includes a first cover member 71 that covers the intake cam chamber 49 of the cam cap plate 34, and a second cover member 72 that covers the exhaust cam chamber 50 of the cam cap plate 34. Are provided individually. The ends of the first cover member 71 and the second cover member 72 on the side of the cam sprockets 37 and 38 are connected by a first connection portion 73. A sealing surface 74 is formed on a surface of the first connection portion 73 on the side of the cam sprockets 37 and 38 along an outer peripheral portion thereof.
Is fitted to the step portion of the first connection portion 73, and the end surface is attached in close contact with the sealing surface 74. That is, the sealing of the ends of the first cover member 71 and the second cover member 72 with respect to the timing belt cover 70 is performed by the sealing surface 74 of the first connection portion 73.
This makes it possible to form them flush. The intake cam chamber 49 and the exhaust cam chamber 50 of the engine 31 are separated from the cam sprockets 37 and 38 by the first connecting portion 73 being in close contact with the cam cap plate 34 via the seal member 63. It is in a state.

The opposite ends of the first cover member 71 and the second cover member 72 are connected by a second connecting portion 75, so that a predetermined rigidity is ensured. Since the respective ends of the first cover member 71 and the second cover member 72 are connected by the first connection portion 73 and the second connection portion 75, one rocker cover 42 is provided.
Is configured. Then, the first cover member 71 and the second
An intake manifold 54 is provided in a space 76 surrounded by the cover member 72, the first connection portion 73, and the second connection portion 75 so as to penetrate therethrough, and is rigidly connected to the cam cap plate 34.

The rocker cover 42 is floatingly supported by the cam cap plate 34 via a single sealing member 63. That is, as shown in FIG. 5, the seal member 63 is formed along the outer periphery of the intake cam chamber 49 and has an intake seal portion 77 interposed between the first cover member 71 and the cam cap plate 34, and an exhaust cam. An exhaust seal portion 78 is formed along the outer periphery of the chamber 50 and is interposed between the second cover member 72 and the cam cap plate 34. One end sides of the intake seal portion 77 and the exhaust seal portion 78 are connected by a first connection seal portion 79 interposed between the first connection portion 73 and the cam cap plate 34, and are connected to the intake seal portion 77. The other end sides of the exhaust seal portion 78 are connected by a second connection seal portion 80 interposed between the second connection portion 75 and the cam cap plate 34.

As described above, the seal member 63 is a single member in which both ends of the intake seal portion 77 and the exhaust seal portion 78 are connected by the first connection seal portion 79 and the second connection seal portion 80. Therefore, the first cover member 71,
Second cover member 72, first connection portion 73, second connection portion 75
Of the cam cap plate 34 to which the rocker cover 42 is attached can be kept uniform in the sealing height, and the sealing surface can be made uniform over the entire circumference. Therefore, even the engine 31 having the upright intake port 45 can support the first cover member 71 and the second cover member 72 with the sealing performance secured.

Further, in order to secure a plurality of insertion portions 84 for fixing bolts 81 in the sealing member 63, similarly to the above-described cam cap plate 34, each of the insertion portions 8 is provided.
4 around the notch 86 of the cam cap plate 34.
A curved portion 87 is formed corresponding to.

In the process of assembling the engine having the above-described configuration, as shown in FIG. 1, a cylinder block 32 is previously assembled with a crankshaft 39 and a piston (not shown) to form a cylinder block assembly. , Cylinder head 33, two camshafts 35 and 36, cam cap plate 34 and each valve 4
The cylinder head assembly is obtained by assembling the components 7, 48 and the like. Then, two sets of cylinder head assemblies (cylinder heads 33) are placed on the cylinder block assembly (cylinder block 32), and as shown in FIG. Then, the fixing bolt 81 is fastened by inserting the tool 85.

At this time, the cam cap plate 34 corresponding to each fixing bolt 81 is provided with an insertion portion 84 having a notch 86, and by using this insertion portion 84, the tool 85 can be easily moved to the cylinder. The cylinder head assembly (cylinder head 33) can be securely fixed to the cylinder block assembly (cylinder block 32) by rotating and fastening the fixing bolt 81 to the lower part of the head 33. Can be. Finally, the rocker cover 42 is attached to the upper part of each cylinder head assembly (cylinder head 33) via the seal member 63.

As described above, in the cam cap structure of the engine according to the present embodiment, when the cylinder head assembly (cylinder head 33) is mounted and fixed on the cylinder block assembly (cylinder block 32), 85 can be inserted from above the cam cap plate 34 to the lower portion of the cylinder head 33 using the insertion portion 84, and the tip of the tool 85 can be engaged with the fixing bolt 81, and the fixing bolt 81 is rotated by the tool 85. The cylinder block assembly (cylinder block 32)
In addition, each cylinder head assembly (cylinder head 33) can be easily and reliably fixed in a short time.

Further, in the cam cap structure of the engine according to the present embodiment, the opposed insertion portions 84 on the intake cam chamber 49 side and the exhaust cam chamber 50 side are located between the ports of each intake manifold 54, and The camshafts 35 and 36 are provided on a straight line along a horizontal direction orthogonal to the axial direction. Therefore, the rocker cover 4
Since the curved portion 87 is formed on the second seal member 63, even if the outer shape of the gasket 91 corresponding to the curved portion 87 is notched, the sealing performance of the connection portion between the intake manifold 54 and the cam cap plate 34 by the gasket 91 is improved. Do not spoil. Further, transmission of vibration of the intake manifold 54 can be prevented without interference between the seal surface of the rocker cover 42 and the seal surface of the intake manifold 54.

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 drawn 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.

[0040]

As described above in detail in the embodiment, according to the engine cam cap structure of the first aspect of the present invention, on the both sides of the central portion of the integral cam cap fixed above the cylinder head, An insertion portion for a first fixing member for fixing the cylinder head to the cylinder block is provided, and an integral cam cap is provided around the insertion portion.
Notches are provided on both sides of the center of the cap, so when the cylinder head is fixed to the cylinder block with the integrated cam cap fixed to the cylinder head, insert a tool from above the integrated cam cap. notch parts can be inserted into the cylinder head with the first fixing member to easily operate can be fixed in a short time with ease cylinder head to the cylinder block, a cylinder block and a cylinder head Can be improved.

According to the cam cap structure for an engine of the second aspect of the present invention, a plurality of ports are fastened to the upper surface of the central portion of the integrated cam cap along the axial direction of the cam shaft via a gasket. In the case of the engine structure described above, the notch is provided at a position corresponding to each port in the axial direction of the camshaft, so that the notch is formed without affecting the sealing performance of the gasket of the plurality of ports. Can be.

[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 plan view of a rocker cover.

FIG. 5 is a plan view of a seal member.

FIG. 6 is a vertical cross-sectional view of the cylinder head showing a mounting state of the cylinder head.

FIG. 7 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 intake valve camshaft 36 exhaust valve camshaft 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 Seal member 70 Timing belt cover 71 First cover member 72 Second cover member 73 First connection part 74 Seal surface 75 Second connection part 76 Vacancy 77 Intake seal part 78 Exhaust seal part 81 Fixing bolt (first fixing means) 82 , 83 fixing bolt (second fixing means) 84 insertion part 85 tool 86 notch part 87 curved part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01L 1/04 F02F 1/00 F02F 1/24

Claims (2)

(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. An integral cam cap formed with an upper half of a bearing ;
Intake cam chamber and exhaust cam formed on both sides of the central part of the pump
A first fixing member inserted from above the integral cam cap to fix the cylinder head to the cylinder block; and a first fixing member inserted from above the integral cam cap and attaching the cylinder head to the cylinder head. And a second fixing member for fixing to the center of the integral cam cap .
An insertion portion provided on both sides of the portion for the first fixing member; and a peripheral portion of the insertion portion, the
A cam cap structure for an engine, comprising notches provided on both sides of a central portion . 2. The cam cap structure for an engine according to claim 1, wherein the engine includes a plurality of engine cam caps on a central upper surface of the integral cam cap along an axial direction of a cam shaft.
A structure in which the port is fastened via a gasket,
The cam cap structure for an engine, wherein the notch is provided at a position corresponding to between the ports in the axial direction of the camshaft.