JPH08254155A - Locker cover structure of internal combustion engine - Google Patents

Abstract

PURPOSE: To provide a locker cover structure of an internal combustion engine using parts in common with each other, small in space to remove a locker cover, and suitable for a cab over truck. CONSTITUTION: A locker cover 12 mounted on a cylinder head 11 is of three- division structure consisting of three parts comprising a lower case 27 arranged at the upper part of the cylinder head 11 in such a manner to surround a valve system mechanism 20; an upper case 28 mounted on the upper end part of the lower part 27; and a cover 29 mounted on the upper end part of the upper case 28 in such a manner to close the case 28. The use of parts in common with the locker cover 12 of a base engine and reduction of a space for removal are made compatible with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker cover structure for an internal combustion engine in which a rocker cover is provided above a cylinder head so as to close the circumference of the cylinder head.

[0002]

2. Description of the Related Art In a cab over truck, an engine, for example, a diesel engine 2 (internal combustion engine) is mounted below a cab 1 as shown in FIG. In the cab over truck, a tilt mechanism 3 is usually adopted so that the engine can be easily maintained, and the chassis 4 can be tilted forward with the front end of the entire cab as a fulcrum.
Mounted on.

For example, in the mounting structure on the front side of the cab 1, front ends of a pair of cab frames 5 and 5 (members extending in the front-rear direction of the vehicle body) located under the cab 1, and a main frame 6 constituting a chassis. , 6 (members extending in the front-rear direction of the vehicle body) are rotatably connected via a hinge mechanism 7 so that the entire cab can be rotated forward, and the hinge mechanism 7 displaces the cab 1 forward. A combination of 8 structures is used.

Further, the rear side mount structure of the cab 1 is provided with a cab bridge 9 formed in a substantially U shape in a vertical shape so as to straddle between the portions of the main frames 6 and 6 corresponding to the rear end of the cab. The structure in which the rear side of the cab 1 is supported and a mechanical lock 10 is provided between the cab 1 and the horizontally extending member portion 9a of the cab bridge 9 is used. The rear side of the cab 1 mounted on is locked or unlocked. 9 shows a hydraulic mechanical lock 10 in which a striker 10a is provided in the cab 1 and a hydraulic latch 10a is provided in the cab bridge 9, for example.

Since the diesel engine 2 mounted on such a cab over truck has a long overall length, it is usually
As shown in FIG. 10, the rear portion is arranged immediately below the cab bridge 9 and is mounted between the main frames 6 and 6.

[0006]

By the way, in the diesel engine 2 mounted on a truck, various mechanisms have been provided in the engine body in order to improve the performance of the vehicle. In addition to valve train components (not shown), a device such as a compression release brake mechanism (engine brake assisting means) is mounted on the upper portion of the cylinder head 11 and accommodated in the rocker cover 12, which is a manifestation thereof. .

When such a separate device is installed in the rocker cover 12, the height of the cylinder head may change, and the total height of the engine may be higher than that of the base engine. When placed on the side).

In such a diesel engine 2, the gap S between the rocker cover 12 and the cab bridge 9 is narrower than ever, because the rocker cover 12 having a large height must be adopted.

In a cab over truck equipped with such a diesel engine 2, it becomes difficult to secure a space necessary for removing the rocker cover 12 (because the gap S becomes small and the height dimension of the rocker cover 12 becomes large). There is a problem that the cab bridge 9 becomes an obstacle and it becomes difficult to remove the rocker cover 12 from the cylinder head 11.

Therefore, it is conceivable to increase the height of the cab bridge 9 or lower the engine mount position. However, this inevitably causes the vehicle height of the truck to be unnecessarily high and the ground clearance to be low.

Moreover, since the rocker cover 12 having the increased height is a component which is completely separate from the rocker cover attached to the base engine, there is a disadvantage that the cost is considerably increased. is there.

Therefore, there is a demand for a technique capable of handling the rocker cover 12 without causing unnecessary trouble. In the figure, 13 is a cylinder block of the diesel engine 2, 14 is an oil pan, and 15 is a front wheel (steering wheel).

The present invention has been made in view of the above circumstances, and an object thereof is to provide a high cylinder head in which the space for removing the rocker cover can be small while sharing the parts of the rocker cover. An object is to provide a suitable rocker cover structure for an internal combustion engine.

[0014]

In order to achieve the above object, the invention set forth in claim 1 is to provide a rocker cover, which is provided at an upper part of a cylinder head of an internal combustion engine so as to surround valve operating system parts and has an open upper surface. A lower case, a frame-shaped upper case with an upper end attached to the upper end of the lower case having the same shape as the upper end of the lower case, and an upper end of the upper case so as to close the same. It has a three-part structure consisting of three parts, a cover and a cover, and is designed to share parts with the rocker cover of the base engine and to reduce the space for removal.

In addition to the above object, the invention described in claim 2 provides a lock cover structure suitable for a cylinder head having an increased height dimension by mounting an engine brake assisting means, in order to obtain a lock cover structure. The cylinder head of the above has a cylinder head structure in which the engine brake assisting means for releasing the pressure in the cylinder to assist the engine braking action is installed above the valve train system parts, and the upper case is used as the engine braking means. It has been arranged to surround.

In addition to the above object, the invention as set forth in claim 3 enables the oil separation structure to be used as it is even if the height of the cylinder head changes due to a change around the valve operating system parts on the upper part of the cylinder head. Therefore, the blow-by gas passage opening is provided in the lower case according to claim 1 or 2.

[0017]

According to the invention described in claim 1, since each part of the rocker cover whose height is increased is divided into a lower case, an upper case and a cover, a space required for removing the rocker cover is provided. As a low-high cover,
Similarly, a small work space is sufficient for removing parts such as the upper case.

Moreover, since the upper end of the upper case has the same shape as the upper end of the lower case, the rocker cover of the base engine is assembled by combining the lower case and the cover excluding the upper case. Becomes,
Only by changing the stacking of the upper case, it will be shared with the rocker cover of the base engine.

According to the second aspect of the present invention, in the case of the cylinder head having the engine brake assisting means, the upper case is arranged so as to surround the engine brake assisting means to form the rocker cover.

That is, the rocker cover structure is suitable for the cylinder head provided with the engine brake assisting means. According to the invention described in claim 3, even if the height of the cylinder head is changed due to the change around the valve operating system parts in the upper part of the cylinder head, the blow-by gas passage opening is attached to the lower case, and therefore, as it is. It is possible to use the oil separation structure.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in FIGS. However, in the present embodiment, the same parts as those described in the above-mentioned "prior art" and "problems to be solved by the invention" are designated by the same reference numerals, and the description thereof will be omitted. Now, different parts (main parts of the invention) will be described.

The present embodiment differs from the diesel engine described above in the rocker cover structure. The upper portion of the diesel engine 2 (internal combustion engine) including this rocker cover structure is shown in FIGS.

The structure of the upper portion of the diesel engine 2 will be described. Reference numeral 11 is a cylinder head, and 20 is a valve mechanism mounted on the cylinder head 11. The valve mechanism 20 uses the rocker arm 2 to detect displacement of a cam shaft (not shown) transmitted to the push rod 21, for example.
2. The structure of the overhead valve system is adopted in which the intake / exhaust valve 24 is transmitted through the rocker lever 23.
These valve operating system components constitute a valve operating system 25 having, for example, two valves on the intake side and two valves on the exhaust side per cylinder.

A compression release brake mechanism 26 (corresponding to engine brake assisting means) is provided above the cylinder head 11 as a device for enhancing the performance of the vehicle to release the pressure in the cylinder of the diesel engine 2 to assist the engine braking action. ) Is installed.

The component 26a constituting the compression release brake mechanism 26 is also disposed on the upper side of the rocker arm 22, and the height dimension of the cylinder head 11 is as shown in FIG. The height is higher than that of the cylinder head 11a of the base engine 2a shown in FIG. 7 (the cylinder head on which the compression release brake mechanism 26 is not mounted).

A rocker cover 12 having a high height is provided above the cylinder head 11 so as to surround the valve system 25 and the compression release brake mechanism 26. Unlike the conventional structure, the rocker cover 12 has a lower case 27 and an upper case 2 as shown in FIGS. 4 and 5.
The structure is divided into three parts such as 8 and cover 29.

Explaining the rocker cover structure, the lower case 27 is formed in a frame shape and is erected on the outer peripheral portion of the upper end of the cylinder head 11 by bolting.
The lower case 27 is composed of a wall having a low height, which is continuous along the circumferential direction of the cylinder head 11, for example, a peripheral wall made of aluminum.
Surrounding 5 from the surroundings.

An injection pipe 30 is penetrated through the lower case 27 as shown by a chain double-dashed line in FIG. 4, and an injection nozzle (not shown) installed at the center of the head of the cylinder through the injection pipe 30. ) To the fuel.

A blow-by gas passage opening 31 (hereinafter, simply referred to as an opening 31) is provided on a wall portion on one side in the left-right direction of the lower case 27 so as to be on the left side in FIG. The outer end of the opening 31 is connected to the intake system (not shown) of the diesel engine 2 or is open to the atmosphere via a blow-by gas outlet 32, a tube (not shown) and the like.

On the inner surface of the lower case 27, the opening 3
A cover member 33 for oil separation is integrally provided so as to cover the opening of No. 1, and the inner surface of the lower case 27 and the cover member 3 are provided.
A passage 34 is formed between the upper and lower ends of the opening 2 and the opening 31.

The blow-by gas that fills the rocker cover 12 is separated from the oil 34a by the passage 33 whose front surface is closed and whose upper and lower ends are open.
It has a structure that can lead to.

The upper case 28 is formed of, for example, an aluminum frame-shaped part having an open upper surface and a lower surface, and is stacked on the upper end of the lower case 27. Cover 29
Is formed of a synthetic resin member, for example, in the shape of a box that closes the upper opening of the upper case 28.

The cover 29 is stacked on the upper end of the upper case 28 so as to close the upper end opening of the upper case 28. And, the lower case 2 that overlaps these three layers
7, the upper case 28, and the cover 29 are connected to each other through the cover 29 from the upper side as shown in FIG.
Long bolt 3 that is screwed into the lower case 27 via 8
5, it is detachably fastened, and as shown in FIG. 4, the upper side of the cylinder head 11, that is, the valve operating system 25 and the compression release brake mechanism 26 are hermetically sealed.

The lower case 27 and the upper case 2 are provided by the pressing cylinder 36, which is a short cylinder inserted together with the bolt 35.
8. The three members of the cover 29 are fastened so that the lower case 27 and the upper case 28 are in close contact with each other, and the rubber member 37 made of rubber is interposed between the upper case 28 and the cover 29 so as to float (noise). (For the purpose of measures).

In the rocker cover structure, the upper case 28 surrounds the compression release brake mechanism 26 projecting above the valve train 6, and the upper end of the upper case 28 has the same shape as the upper end of the lower case 7a. The structure is adopted,
A cylinder head 11a (low cylinder head) in which only the valve operating system 25 as shown in FIGS. 6 and 7 is mounted.
In this case, the rocker cover 12 is assembled from the combination of the two parts of the lower case 27 and the cover 29, and the valve system 25 and the compression release brake mechanism 26 as shown in FIGS. 4 and 6 are mounted. In the case of the cylinder head 11 (high cylinder head), the rocker cover 12 can be assembled from a combination of three parts including a lower case 27, an upper case 28, and a cover 29.

That is, the lower case 27 and the cover 29 are used as common parts for both the cylinder head 11a and the cylinder head 11, so that the rocker cover 12 suitable for the engine can be constructed for each engine type.

Next, the operation of the rocker cover structure thus constructed will be described. Now, as shown in FIGS. 1 to 3, the diesel engine 2 is mounted between the main frames 6 and 6, and the rear portion of the engine is arranged immediately below the cab bridge 9.

At this time, since the diesel engine 2 has a high cylinder head by mounting the compression release brake mechanism 26, the gap S between the rocker cover 12 and the cab bridge 9 is narrow.

Here, for example, for maintenance of the engine,
It is assumed that the rocker cover 12 is removed. At this time, first, the bolts 35 fixing the upper case 28 and the cover 29 are pulled out upward to release the fixing of the upper case 28 and the cover 29.

After this, as shown by the chain double-dashed line in FIG. 1 and FIG. 8, the cover 29 constituting the uppermost stage of the rocker cover 12 is lifted up and guided to the gap S with the cab bridge 9.

At this time, since the height dimension is considerably reduced by adopting the divided structure, the cover 29 can be easily removed by utilizing the narrowed gap S for the working space.

Then, after the cover 29 is removed, the upper case 28 constituting the middle stage of the rocker cover 12 is similarly lifted upward to guide it into the gap S between the cab bridge 9 and the cover 29. As with the time, the space S is used as a work space to allow the upper case 28
Is easy to remove.

That is, since each part of the rocker cover 12 whose height is increased is divided into the lower case 27, the upper case 28 and the cover 29, the space required to remove the rocker cover 12 is as follows. Low high cover 2
9. Similarly, it is sufficient if the work space is small enough to remove parts such as the upper case 28.

Therefore, by adopting the split type rocker cover structure, the space for removing the rocker cover 12 can be small. Moreover, the shape of the upper end is lower case 27.
By adopting the upper case 28 having the same shape as the upper end of the base, as shown in FIGS. 6 and 7, the rocker of the base engine 2a (only the valve system 25 is mounted on the cylinder head 11a) is used. The cover 12 is a lower case 27.
The rocker cover 12 and the rocker cover 12a can be assembled simply by changing the stacking method of the upper case 28. That is, the rocker cover 12 is suitable for a high cylinder head while making the parts common.
Can be obtained.

Particularly, if the structure in which the upper case 28 is arranged so as to surround the compression release brake mechanism 26 is adopted,
The rocker cover structure is suitable for two types of engines, the cylinder head 11 having the compression release brake mechanism 26 mounted therein and the cylinder head 11a of the base engine 2a.

Moreover, in the structure in which the bolts 35 are inserted into the lower case 27, the upper case 28, and the cover 29 that are stacked and fastened, it is only necessary to change the long-length bolts 35 to the short-length bolts 35a. This brings the effect that the cover 29 can be fixed.

In addition, if the structure in which the opening 31 is provided in the lower case 27 is adopted, even if the height of the cylinder head 11 changes due to the change around valve operating system components, that is, the mounting of the compression release brake mechanism 26, blow-by gas is generated. Since the passage remains attached to the lower case 27, the oil separation structure can be used as it is, and the structure is also excellent in that the blow-by gas passage is shared.

In one embodiment, the present invention is applied to an engine in which the cylinder head 11 is elevated by mounting the compression release brake mechanism 26, but the invention is not limited to this, and other mechanisms and means are provided above the cylinder head 11. It goes without saying that the present invention can be applied even when mounted and the height becomes higher than the height dimension of the cylinder head 11a of the base engine 2a. Of course, the present invention can be applied to an engine (internal combustion engine) having a rocker cover other than a diesel engine.

[0049]

As described above, according to the first aspect of the present invention, the space for removing the rocker cover is small due to the split type rocker cover structure. Moreover, by using the upper case whose upper end portion has the same shape as the upper end portion of the lower case, it is possible to obtain a rocker cover suitable for a high cylinder head while achieving common parts.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, a rocker cover structure suitable for a cylinder head having an increased height dimension by mounting engine brake assisting means is obtained. be able to.

According to the third aspect of the invention, in addition to the effects of the first and second aspects of the invention, the height of the cylinder head is changed due to the change around the valve operating system parts on the upper part of the cylinder head. However, the oil separation structure can be used as it is.

[Brief description of drawings]

FIG. 1 is a perspective view showing a front side of a cab over truck to which a split type rocker cover structure according to an embodiment of the present invention is applied.

FIG. 2 is a side view of the cab overtrack.

FIG. 3 is a view of the cab overtrack as viewed from the rear side.

FIG. 4 is a cross-sectional view showing a structure of an engine upper part for explaining a rocker cover structure.

FIG. 5 is an exploded sectional view of the rocker cover structure.

FIG. 6 is a sectional view for explaining that parts of the rocker cover structure are made common.

FIG. 7 is a cross-sectional view for explaining around a rocker cover of a base engine in which only the valve train is mounted.

FIG. 8 is a sectional view for explaining a process when the split rocker cover structure is opened for engine maintenance.

FIG. 9 is a perspective view for explaining an engine mounting structure in a cab over truck.

FIG. 10 is a side view of the cab overtrack.

FIG. 11 is a view of the cab overtrack as viewed from the rear side.

[Explanation of symbols]

1 ... Cab 2 ... Engine
3 ... Tilt mechanism 9 ... Cab bridge 11 ... Cylinder head
12 ... Rocker cover 20 ... Valve mechanism 26 ... Compression release brake mechanism (engine brake auxiliary means) 27 ... Lower case 28 ... Upper case
29 ... Cover 31 ... Blow-by gas passage opening.

Claims (3)

[Claims] 1. A lower case, which is provided on an upper part of a cylinder head of an internal combustion engine so as to surround valve operating system parts, and whose upper surface is open, and an upper surface and a lower surface, which are attached to an upper end portion of the lower case. A frame-shaped upper case having an upper end having the same shape as the upper end of the lower case opened, and a cover attached to the upper end of the upper case so as to close the same. A rocker cover structure for an internal combustion engine. 2. The cylinder head is equipped with an engine brake assisting means for releasing the pressure in the cylinder to assist the engine braking action above the valve operating system part, and surrounds the engine brake assisting means. 2. The rocker cover structure for an internal combustion engine according to claim 1, wherein the upper case is disposed in the upper case. 3. The lower case is provided with an opening for a blow-by gas passage.
Alternatively, the rocker cover structure for an internal combustion engine according to claim 2.