JP3075039B2 - Tightening structure of cylinder head cover - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tightening structure for a cylinder head cover, and more particularly, to two parallel intake and exhaust camshafts disposed on an upper portion of a cylinder head and a timing chain at one end of the intake camshaft. The present invention relates to a tightening structure of a cylinder head cover that surrounds a timing chain wound around a sprocket, and a cam chain wound around an intake cam and an exhaust cam sprocket provided on an intake cam and an exhaust cam shaft, respectively.

[0002]

2. Description of the Related Art In an engine, there is provided a valve operating system in which a camshaft is disposed above a cylinder head, a cam housing for supporting the camshaft is provided, and the cam housing is fixed to the cylinder head by a housing mounting bolt. Provided.

As the valve train 112, for example, as shown in FIG. 5, there is one provided in the engine 102. That is, as shown in FIG. 5, in the valve train 112, an intake camshaft 114 and an exhaust camshaft 116 are disposed in parallel above the cylinder head 106.
Of the first intake cam housing 13
4. Each of the exhaust journal portions of the exhaust camshaft 116 is pivotally supported by the first exhaust cam housing 138, the second exhaust cam housing 140, and the like.

The first and second intake cam housings 13
4, 136 are two intake housing mounting bolts 144
At two points on the cylinder head 106.

Similarly, the first and second exhaust cam housings 1
38, 140 are two exhaust housing mounting bolts 14
6 support two points on the cylinder head.

Further, a timing chain sprocket 124 is fixedly mounted on the intake camshaft 114 at one end of the intake camshaft 114, and an intake cam sprocket 118 is provided between the first intake cam housing 134 and the second intake cam housing 136. Is fixed.

The exhaust camshaft 116 has an exhaust cam sprocket 1 corresponding to the intake cam sprocket 118.
20 are provided.

[0008] A cam chain 128 is wound around the intake cam sprocket 118 and the exhaust cam sprocket 120.

The timing chain sprocket 124
, A timing chain 126 is wound.

Further, as disclosed in Japanese Utility Model Laid-Open Publication No. 56-27342, a plastic cylinder head cover is provided with nuts for fixing the cover main body to the cylinder head with bolts and nuts at a plurality of positions on the peripheral edge of the cover main body. In a plastic cylinder head cover with a seat formed, a plurality of concave portions that are inwardly depressed are formed on the peripheral edge of the cover body at appropriate intervals, and a horizontal rib that is bridged between opposing side walls of the concave portion is provided at a height of the cover body. It is located in the middle part of the direction and is installed in the cylinder head on the horizontal rib, the horizontal rib is used as a nut tightening seat, and the nut tightening force is distributed to the lower end mating surface of the cover body of the adjacent nut tightening seat In some cases, the pressure distribution is distributed over the lower end mating surface of the cover body to average the surface pressure distribution over the entire lower end mating surface of the cover body.

[0011]

In the conventional engine, as shown in FIGS. 5 and 6, an intake side stud bolt for the cylinder head cover 122 is provided outside the second intake cam housing 136 to which the intake cam shaft 114 is attached. 1
50A, and an exhaust-side stud bolt 150B for the cylinder head cover 122 is provided outside the second exhaust cam housing 140 to which the exhaust cam shaft 116 is attached.

The cylinder head cover 122
Are stud bolts 150A, 15
0B was fixed to the intake side and exhaust side nuts 152A and 152B.

As a result, the chain sound generated when the timing chain 126 and the cam chain 128 are driven diverges to the outside via the cylinder head cover 122, causing noise, which is disadvantageous in practical use.

Further, since the cylinder head cover 122 is vibrated by the vibration generated when the timing chain 126 and the cam chain 128 are driven, the sealing performance of the gasket 156 disposed between the cylinder head cover 122 and the cylinder head 106 is improved. There is a possibility that the oil may leak and oil leakage may occur, which is disadvantageous in practical use.

In order to avoid the above-mentioned inconveniences, there are measures to increase the thickness of the cylinder head cover 122 and to add a reinforcing rib (not shown) in order to improve the rigidity of the cylinder head cover 122. However, there is a disadvantage that the weight of the engine 102 is increased, which is disadvantageous in practical use, increases production cost, and is economically disadvantageous.

[0016]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides two parallel intake and exhaust camshafts disposed above a cylinder head, and one end of the intake camshaft. In the cylinder head cover surrounding the timing chain wound around the timing chain sprocket and the cam chains wound around the intake and exhaust cam sprockets respectively provided on the intake and exhaust cam shafts, the timing chain and cam chain are abbreviated. An intermediate portion is provided with a mounting portion for a cylinder head cover for mounting the cylinder head cover to the cylinder head.

[0017] Also, 2 is disposed above the cylinder head.
The parallel intake and exhaust camshafts, the timing chain wrapped around the timing chain sprocket at one end of the intake camshaft, and the intake and exhaust cam sprockets provided on the intake and exhaust camshafts, respectively. In the cylinder head cover surrounding the cam chain, an intake cam housing for holding an intake cam shaft is provided at a substantially intermediate portion between the timing chain and the cam chain at the upper portion of the cylinder head, and stud bolts are provided to attach the cylinder head cover to the intake cam housing. A cylinder head cover mounting portion having a nut engaged with the stud bolt from the outside of the cylinder head cover is provided.

[0018]

According to the invention as described above, the cylinder head cover is attached to the cylinder head by the cylinder head cover attaching portion provided substantially at the intermediate portion between the timing chain and the cam chain.

An intake cam housing disposed at a substantially intermediate portion between the timing chain and the cam chain at the upper portion of the cylinder head by a cylinder head cover mounting portion having a stud bolt and a nut engaged with the stud bolt from the outside of the cylinder head cover. With a cylinder head cover.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 4 show an embodiment of the present invention. In FIG. 2, reference numeral 2 denotes an engine. The engine 2 has a cylinder head 6 mounted on an upper part of a cylinder block 4.

A crankshaft 8 is supported at a lower portion of the cylinder block 4. A crank sprocket 10, which is a driving sprocket, is fixedly attached to one end of the crank shaft 8.

Above the cylinder head 6, intake and exhaust camshafts 14, 16 are arranged in parallel at both ends of the upper portion to constitute the valve train 12, that is, in parallel. Intake and exhaust cam sprockets 18 and 20 are fixedly attached to the intake and exhaust camshafts 14 and 16. The cylinder head 6 is provided with a cylinder head cover 22.

At one end of the intake camshaft 14, a timing chain sprocket 24 is mounted.

The crank sprocket 10 and the timing chain sprocket 24 have a timing chain 2
6 is provided by winding.

A cam chain 28 is wound around the intake cam sprocket 18 and the exhaust cam sprocket 20.

An oil pump chain sprocket 30 having substantially the same diameter as the crank sprocket 10 is provided at one end of the crankshaft 8.

The oil pump chain 32 wound around the oil pump chain sprocket 30 is connected to an oil pump sprocket (not shown) of an oil pump (not shown).
It is wound around.

The valve train 1 above the cylinder head 6
2, each journal portion of the intake camshaft 14 is supported by a first intake cam housing 34, a second intake cam housing 36,... Sequentially from one end side, as shown in FIGS.

Each of the journal portions of the exhaust camshaft 16 is also supported by a first exhaust cam housing 38, a second exhaust cam housing 40,... .

The timing chain sprocket 24
Are fixedly mounted at the extreme end on one end side of the intake camshaft 14 by sprocket mounting bolts 42. Further, the intake cam sprocket 18 is provided in the first intake cam housing 3.
It is fixed to the intake camshaft 14 between the fourth and second intake cam housings 36.

The exhaust cam sprocket 20 is fixed to the exhaust cam shaft 16 between a first exhaust cam housing 38 and a second exhaust cam housing 40 at a position corresponding to the intake cam sprocket 18.

The first intake cam housing 34 at one end of the intake cam shaft 14 is supported at three points on the cylinder head 6 by intake housing mounting bolts 44.

The two ends of each of the second intake cam housings 36, which support the other journal portions of the intake cam shaft 14, are supported at two points by intake housing mounting bolts 44, respectively.

Each end of each of the first and second exhaust cam housings 38, 40 ... which supports the exhaust cam shaft 16 is supported at two points by exhaust housing mounting bolts 46, respectively.

A cylinder head cover 2 is provided at a substantially intermediate portion between the timing chain 26 and the cam chain 28.
A cylinder head cover mounting portion 48 for mounting the cylinder head 2 to the cylinder head 6 is provided.

More specifically, the cylinder head cover 2 is provided substantially at the center of a first intake cam housing 34 which is an intake cam housing disposed substantially at an intermediate portion between the timing chain 26 and the cam chain 28 above the cylinder head 6.
A mounting portion 48 for a cylinder head cover having a stud bolt 50 and an engaging nut 52 from the outside of the cylinder head cover 22 to the stud bolt 50 for mounting the stud bolt 2.
Is provided.

A hole 54 through which the stud bolt 50 is inserted is formed in the cylinder head cover 22 at a position corresponding to the stud bolt 50.

Reference numeral 56 denotes a cylinder head cover 2
Gasket disposed between the cylinder head 2 and the cylinder head 6, 58
Is a chain cover.

Next, the operation of this embodiment will be described.

When the timing chain 26 rotates with the rotation of the crank sprocket 10 fixed to the crankshaft 8, the intake camshaft 14 rotates via the timing chain sprocket 24.

The rotation of the intake cam sprocket 18 fixed to the intake cam shaft 14 causes the cam chain 28 to rotate.
Is rotated, the exhaust camshaft 16 is rotating via the exhaust cam sprocket 20.

Further, the cylinder head cover 22 is substantially intermediate between the timing chain 26 and the cam chain 28 by a cylinder head cover mounting portion 48 having a stud bolt 50 and a nut 52 engaged with the stud bolt 50 from outside the cylinder head cover 22. It is attached to a first intake cam housing 34 disposed at the site.

As a result, the vibration and noise of the cylinder head cover 22 generated when the timing chain 26 and the cam chain 28 are driven can be reduced without increasing the weight and the manufacturing cost of the engine 2, and the cost can be kept low. This is economically advantageous and practically advantageous.

Also, by reducing the vibration of the cylinder head cover 22 generated when the timing chain 26 and the cam chain 28 are driven, the sealing property of the gasket 56 disposed between the cylinder head cover 22 and the cylinder head 6 is reduced. And oil leakage can be reliably prevented, which is practically advantageous.

[0046]

As is apparent from the above detailed description, according to the present invention, two parallel intake and exhaust camshafts arranged on the upper part of the cylinder head and a timing chain sprocket at one end of the intake camshaft. In the cylinder head cover that surrounds the timing chain wound around the cam chain and the intake and exhaust cam sprockets provided respectively on the intake and exhaust cam shafts, a cylinder is provided at a substantially intermediate portion between the timing chain and the cam chain. The cylinder head cover mounting part that attaches the head cover to the cylinder head is provided, so the vibration and noise of the cylinder head cover generated when the timing chain and cam chain are driven can be reduced without increasing the weight and manufacturing cost of the engine. It is more advantageous. Further, since the vibration of the cylinder head cover generated when the timing chain and the cam chain are driven is reduced, the sealing performance of the engine can be improved and oil leakage can be prevented, which is practically advantageous.

[0047] Also, 2 is provided above the cylinder head.
The parallel intake and exhaust camshafts, the timing chain wrapped around the timing chain sprocket at one end of the intake camshaft, and the intake and exhaust cam sprockets provided on the intake and exhaust camshafts, respectively. In the cylinder head cover surrounding the cam chain, an intake cam housing for holding an intake cam shaft is provided at a substantially intermediate portion between the timing chain and the cam chain at the top of the cylinder head, and a stud bolt and a stud are provided to attach the cylinder head cover to the intake cam housing. Since the cylinder head cover mounting portion having the nut engaged with the bolt from the outside of the cylinder head cover is provided, the vibration of the cylinder head cover generated when the timing chain and the cam chain are driven without increasing the weight and the manufacturing cost of the engine. And reduce noise Can, which is advantageous in practical use. Also,
By reducing the vibration of the cylinder head cover that occurs when the timing chain and cam chain are driven,
The sealability of the engine can be improved, and oil leakage can be prevented, which is practically advantageous.

[Brief description of the drawings]

FIG. 1 is a plan view of a cylinder head valve train showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view of the engine taken along line II-II of FIG.

FIG. 3 is a schematic sectional view of the engine taken along the line III-III of FIG.

FIG. 4 is a schematic bottom view of the cylinder head cover.

FIG. 5 is a plan view of a cylinder head valve train showing the prior art of the present invention.

FIG. 6 is a schematic sectional view of an engine.

[Explanation of symbols]

 2 Engine 4 Cylinder block 6 Cylinder head 8 Crankshaft 10 Crank sprocket 12 Valve train 14 Intake camshaft 16 Exhaust camshaft 18 Intake cam sprocket 20 Exhaust cam sprocket 22 Cylinder head cover 24 Timing chain sprocket 26 Timing chain 28 Cam chain 34 First intake Cam housing 36 Second intake cam housing 38 First exhaust cam housing 40 Second exhaust cam housing 42 Sprocket mounting bolt 44 Intake housing mounting bolt 46 Exhaust housing mounting bolt 48 Cylinder head cover mounting part 50 Stud bolt 52 Nut 54 Hole 56 Gasket 58 Chain Cover

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-189360 (JP, A) JP-A-63-83464 (JP, A) JP-A-2-267347 (JP, A) 27342 (JP, U) JP-A-2-85851 (JP, U) JP-A-59-68165 (JP, U) JP-A 60-173602 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F02F 7/00 F01L 1/02 F02F 1/24 F16M 1/026

Claims (2)

(57) [Claims] 1. An intake camshaft, two parallel intake and exhaust camshafts disposed on an upper portion of a cylinder head, a timing chain wound around a timing chain sprocket at one end of the intake camshaft, and an intake and exhaust camshaft. In a cylinder head cover surrounding the intake and exhaust cam sprockets provided respectively around the cam chain, a mounting portion for a cylinder head cover for mounting the cylinder head cover to the cylinder head is provided at a substantially intermediate portion between the timing chain and the cam chain. A tightening structure for a cylinder head cover. 2. The intake and exhaust camshafts, two parallel intake and exhaust camshafts disposed on an upper portion of the cylinder head, a timing chain wound around a timing chain sprocket at one end of the intake camshaft, and two intake and exhaust camshafts. In the cylinder head cover surrounding the intake and exhaust cam sprockets provided around the intake and exhaust cam sprockets, an intake cam housing for holding the intake cam shaft is provided at a substantially intermediate portion between the timing chain and the cam chain at the upper part of the cylinder head. And
A tightening structure for a cylinder head cover, comprising a cylinder head cover mounting portion having a stud bolt and a nut engaged with the stud bolt from the outside of the cylinder head cover to mount the cylinder head cover on the intake cam housing.