JP2000054912A - Structure of cylinder head cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder head cover capable of restricting generation of vibration accompanied with actuation of engine. SOLUTION: A plate-like rib 8 is provided at a generally central part in a longitudinal direction of a head cover main body in an upper surface of the head cover main body, and the rib 8 connects two projections 3. Since the rib 8 connects the two projections 3, rigidity of the two projections 3 in a swinging direction (width direction) becomes large. Accordingly, the two projections 3 are restrained from swinging accompanied with vibration of engine, whereby vibration of a cylinder head cover is reduced to reduce a radiation sound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a cylinder head cover used in a twin cam type four-stroke engine.

[0002]

2. Description of the Related Art Generally, a cylinder head cover mounted on a cylinder block is provided with a cylinder head cover to cover a camshaft. The shape of the cylinder head cover is different between the case of one camshaft and the case of two camshafts. Generally, the former is classified as a single cam type cylinder head cover, and the latter is classified as a twin cam type cylinder head cover. The single cam type cylinder head cover 1A has a substantially rectangular parallelepiped box shape as shown in FIG.

A twin cam type cylinder head cover 1 has a head cover body 2 having a substantially rectangular shape in plan view (see FIG. 18) and, as shown in FIG. 17, both side portions of the head cover body 2 in the width direction (horizontal direction in FIG. 17). In a longitudinal direction (FIG. 18) which is formed so as to protrude from the inside to the outside.
(A left-right direction). As described above, since the two convex portions 3 are provided so as to be pushed outward from the inside, two concave portions 4 extending in the longitudinal direction of the head cover main body 2 are formed inside. The two recesses 4 are provided with a camshaft having a cam for an intake valve (not shown) (camshaft for an intake valve) and a camshaft having a cam for an exhaust valve not shown (a camshaft for an exhaust valve).
Are stored respectively.

As shown in FIGS. 18 and 19, a twin cam type cylinder head cover 1 has a portion (hereinafter referred to as a cam pulley cover for convenience) which covers a cam pulley (not shown) on one side in the longitudinal direction (left side in FIG. 18). 20 is additionally provided in a cover main body having a substantially rectangular shape in plan view, or as shown in FIG.
Some types do not have a. 18 and FIG.
In FIG. 9, reference numeral 6 denotes an ignition plug arrangement portion (ignition plug arrangement portion) 6 not shown.

[0005] By the way, the cylinder head cover (1A,
1) generates radiated sound when excited by engine vibration. In particular, when the natural frequency of the cylinder head cover (1A, 1) matches the resonance frequency, the vibration level increases. For example, in the case of a four-cylinder engine, the number of revolutions is 6000r
The resonance frequency at pm is 200 Hz, and if the natural frequency is 200 Hz, the vibration becomes extremely large at a rotation speed of 6000 rpm.

Here, the vibration of the cylinder head cover (1A, 1) will be described with reference to FIGS. Cylinder head cover (1A, 1)
First exhibits a mode D in which the upper surface of the cylinder head cover 1A vibrates up and down (hereinafter, appropriately referred to as a vertical vibration mode) according to the engine vibration. 21 and FIG.
2 and FIG. 23 and FIG. 24 show how the twin cam type cylinder head cover 1 vibrates. ). The vibration of the upper surface of the cover radiates the vibration sound of the engine and the sound of the timing chain to the outside of the engine. The twin cam type cylinder head cover 1
Has two convex portions 3 as described above,
In addition to the above-described vertical vibration of the upper surface of the cover, FIGS.
As shown in FIG. 6, a mode E unique to the twin cam type in which each projection 3 swings in the width direction (hereinafter, appropriately referred to as a swing mode) E is exhibited.

In order to avoid a situation in which the vibration of the cylinder head cover becomes extremely large as described above, the natural frequency is shifted to a value other than the normal rotation speed (for example, in the case of a four-cylinder engine, the resonance speed is set at 10,000 rpm and The frequency is 333 Hz, and the natural frequency is set to a value exceeding 333 Hz.), Or the vibration amplitude of the cylinder head cover is reduced. In this measure, for example, the thickness of the cylinder head cover is increased, or a reinforcing rib is provided inside the cylinder head cover.

[0008]

However, increasing the wall thickness as described above causes an increase in weight, which is disadvantageous to engine performance and fuel efficiency. Further, there is a valve operating system component such as a camshaft inside the cover, and there is a risk of interference, and it is difficult to set the height and arrangement of the reinforcing ribs satisfactorily.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a structure of a cylinder head cover that can suppress generation of vibrations due to operation of an engine.

[0010]

According to the first aspect of the present invention,
A twin cam type cylinder including a head cover body having a substantially rectangular shape in a plan view, and two longitudinally extending protrusions formed on both sides on the width direction side of the head cover body so as to protrude from inside to outside. In the structure of the head cover, a connecting member for connecting the two convex portions is provided. According to a second aspect of the present invention, in the first aspect, the connecting member is provided at a substantially central portion in a longitudinal direction of the head cover body. According to a third aspect of the present invention, in the configuration of the first aspect, the connecting member includes a plurality of members arranged along a longitudinal direction of the head cover body.

[0011] The invention according to claim 4 is the invention according to claims 1 to 3.
Wherein the connecting member is a plate-shaped rib suspended from the head cover body. According to a fifth aspect of the present invention, in the configuration according to any one of the first to third aspects, the connecting member is a bridge portion formed so as to bridge the two convex portions. According to a sixth aspect of the present invention, in the configuration according to any one of the first to third aspects, the connecting member is a connecting plate member separate from the convex portion provided to bridge the two convex portions. It is characterized by the following. According to a seventh aspect of the present invention, in the configuration according to any one of the first to third aspects, the connecting member is a tubular member. According to an eighth aspect of the present invention, in the configuration of the seventh aspect, the tubular member is also used as a blow-by gas passage.

According to a ninth aspect of the present invention, in the configuration of the first aspect, the connecting member is a stiffener plate made of a rigid material fixed to the two convex portions so as to cover the upper surface of the two convex portions. There is a feature.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a cylinder head cover according to a first embodiment of the present invention will be described below with reference to FIGS. In this case, the cylinder head cover 1 is a twin cam type and is used for a four-cylinder engine. 1 and 2, a cylinder head cover 1 has a head cover body 2 having a substantially rectangular shape in a plan view and a longitudinal direction formed on both sides on the width direction side of the head cover body 2 so as to protrude from inside to outside. And two convex portions 3 extending in the direction of the arrow. As described above, since the two convex portions 3 are provided so as to be pushed out from the inside to the outside, two concave portions 4 extending in the longitudinal direction of the head cover main body 2 are formed inside. The two concave portions 4 accommodate a cam shaft for an intake valve (not shown) and a cam shaft for an exhaust valve (not shown), respectively. In FIG. 1, reference numeral 5 denotes a cam pulley cover for accommodating a cam pulley (not shown), and reference numeral 6 denotes a spark plug arrangement portion. Four ignition plug arrangement parts 6 are provided corresponding to four cylinders.

Since the two convex portions 3 are formed as described above, a groove 7 extending in the longitudinal direction of the head cover main body 2 is formed between the two convex portions 3 on the upper surface of the head cover main body 2. Further, a plate-like rib (connecting member) 8 is vertically provided at a substantially central portion in the longitudinal direction of the head cover main body 2 on the upper surface portion of the head cover main body 2.
The two convex portions 3 are connected. In this case, the bottom side of the groove 7 is set lower on the end side (the end side in the longitudinal direction) of the groove 7 than the portion where the rib 8 is provided, so that water can be drained well. ing.

In the first embodiment configured as described above, since the ribs 8 connect the two convex portions 3, the rigidity of the two convex portions 3 in the swinging direction (width direction) increases. . Therefore, the two convex portions 3 are prevented from exhibiting the swing mode E (see FIG. 25) due to the engine vibration, and the vibration of the cylinder head cover 1 is reduced accordingly, and the radiation noise is reduced. be able to.

In the first embodiment, the case where the connecting member is the rib 8 has been described as an example. Alternatively, as shown in FIGS. 3 and 4, the two convex portions 3 are bridged. The structure of the cylinder head cover (the second embodiment of the present invention) may be configured by using a bridging portion (connecting member) 9 integrally formed with the convex portion 3 (head cover main body 2). As shown in FIG. 9, the structure of the cylinder head cover is provided by using a connecting plate (connecting member) 10 which is provided so as to bridge the two convex portions 3 and is separate from the convex portions 3 (third embodiment of the present invention). 10), or as shown in FIGS. 10 to 12, a cylindrical member (connecting member) 11 connecting two convex portions 3 and also serving as a blow-by gas passage.
May be used to configure the structure of the cylinder head cover (the fourth embodiment of the present invention).

In the second embodiment (FIGS. 3 and 4),
Since the bridging portion 9 connects the two convex portions 3, the rigidity of the two convex portions 3 in the swing direction (width direction) increases. Therefore, the two convex portions 3 are caused to swing in the swing mode E due to the engine vibration.
(Refer to FIG. 25) is suppressed, and the vibration of the cylinder head cover 1 is reduced accordingly, and the radiation noise can be reduced.

The connecting plate 10 of the third embodiment (FIGS. 5 to 9) has a predetermined length (a length that can be placed on the two projections 3) as shown in FIGS. It is roughly composed of a substantially rectangular connecting plate material main body 10a and plate-like legs 10b of a predetermined length vertically provided on both sides of the connecting plate material main body 10a. A hole 10c into which an attachment member (not shown) for the protrusion 3 such as a bolt is inserted is formed at an end of the connection plate material body 10a. In this connecting plate 10, the leg 10b is inserted into the groove 7, the connecting plate main body 10a is cross-linked to the two convex portions 3, and the mounting member inserted into the hole 10c is engaged with the convex portion 3. To connect the two convex portions 3.

In the third embodiment, since the two convex portions 3 are connected by the connecting plate 10, the two convex portions 3 are connected.
The rigidity in the swing direction (width direction) is increased. For this reason,
The two convex portions 3 are moved in the swing mode E (FIG. 2) due to the engine vibration.
5) is suppressed, the vibration of the cylinder head cover 1 is reduced accordingly, and the radiation noise can be reduced.

In the first to third embodiments, the connecting members (the ribs 8, the bridging portions 9, and the connecting plate 10) are provided substantially at the center of the head cover body 2, and the rigidity of the two convex portions 3 is improved. Can be achieved in a well-balanced manner. The present invention relates to a connecting member (rib 8, bridge portion 9, connecting plate 1).
0) is not limited to being provided in the substantially central portion of the head cover main body 2 as described above, and a connecting member (rib 8, bridging portion 9, connecting plate 10) is provided on the end side of the head cover main body 2. Alternatively, the rigidity of the two convex portions 3 may be improved.

Further, in the above-described embodiment, the case where the number of the connecting members (the ribs 8, the bridging portions 9, and the connecting plate 10) is one is exemplified. However, the present invention is not limited to this. ,
The bridge portion 9 and the connecting plate 10 may be provided to further improve the rigidity (that is, for example, in the first embodiment, the case where one rib 8 is used is taken as an example. 8 may be provided two or more.)

Fourth Embodiment (FIGS. 10 to 12)
The cylindrical member 11 is disposed on the bottom surface of the groove 7 on the end side of the head cover main body 2, and both ends are connected to the two convex portions 3. The cylindrical member 11 has two recesses 4 at its both ends.
(Where the camshaft is housed) and, furthermore, it communicates with the inside of the crankcase (not shown), and communicates with the intake system (not shown) through a passage (not shown). It serves as a return passage (blow-by gas passage).

In the fourth embodiment, since the two convex portions 3 are connected by the cylindrical member 11, the rigidity of the two convex portions 3 in the swing direction (width direction) increases. Therefore, the two convex portions 3 are prevented from exhibiting the swing mode E (see FIG. 25) due to the engine vibration, and the vibration of the cylinder head cover 1 is reduced accordingly, and the radiation noise is reduced. be able to.

In the fourth embodiment, the cylindrical member 11
Also serves as a blow-by gas passage. Therefore, compared to a case where a separate blow-by gas passage is provided, the arrangement space is reduced by an amount corresponding to the use of the blow-by gas passage, and the apparatus can be made more compact. In the fourth embodiment, the case where the tubular member 11 is provided on the end side of the head cover main body 2 is described as an example. However, the tubular member 11 may be provided at the center instead. Further, a plurality of tubular members 11 may be provided. Note that the tubular member 11 may be configured to be used for improving the rigidity of the two convex portions 3 without also serving as the blow-by gas passage.

Next, the structure of a cylinder head cover according to a fifth embodiment of the present invention will be described with reference to FIGS. In the fifth embodiment, in addition to the cylinder head cover 1 composed of the head cover main body 2 and the two convex portions 3, a rectangular shape substantially along the head cover main body 2 is formed, and the head cover main body 2 (the convex portion 3) is formed. A stiffener plate (connecting member) 12 having greater rigidity,
A fixing member such as a bolt (not shown) for fixing the stiffener plate 12 to the head cover main body 2 is provided.

The stiffener plate 12 has one side (the upper side in FIGS. 13 and 14) and the other side (the lower side in FIGS. 13 and 14) in the width direction on the upper surface of the two projections 3 respectively. It is placed on the head cover main body 2 while being placed. Four rectangular notches 12a are provided on one side (the upper side in FIGS. 13 and 14) of the stiffener plate 12 in the width direction.
Are formed, so that the four spark plug arrangement portions 6 can be exposed from the notches 12a. Also,
One side of the stiffener plate 12 in the width direction (FIG. 1)
Holes 12b into which fixing members are inserted are formed at the ends of the upper side of FIG. 3, FIG. 14) and the other side (lower side of FIG. 13, FIG. 14), and the stiffener plate 12 covers the two convex portions 3. In this state, it is fixed to the two convex portions 3 (head cover main body 2) by the fixing member.

In the fifth embodiment configured as described above, since the two convex portions 3 are connected by the stiffener plate 12, the rigidity of the two convex portions 3 in the swinging direction (width direction) increases. . Therefore, the two convex portions 3 are prevented from exhibiting the swing mode E (see FIG. 25) due to the engine vibration, and the vibration of the cylinder head cover 1 is reduced accordingly, and the radiation noise is reduced. be able to. Further, since the stiffener plate 12 covers the two convex portions 3 and water is prevented from entering the groove 7, the groove 7
There is no need to provide a slope for draining the bottom surface of the device, so that the number of production steps can be reduced, and the productivity can be improved accordingly.

The radiation sound characteristics of the fifth embodiment described above and the prior art cylinder head cover 1 without the stiffener plate 12 were determined by analysis. Embodiment), and the results shown by the solid line (prior art) were obtained. Although there are three peaks on the solid line, the left two peaks indicate the vertical vibration mode D and the third (right) peak indicates the swing mode E. On the other hand, although the dotted line has two peaks indicating the vertical vibration mode D, the swing mode E corresponding to the third peak of the solid line does not exist, and the fifth embodiment is more favorable. It was confirmed that the generation of the swing mode E was suppressed, and the radiation sound could be reduced.

In the present embodiment, since the stiffener plate 12 has greater rigidity than the head cover body 2 (projection 3), the two projections 3 connected via the stiffener plate 12 are provided. The rigidity in the width direction (oscillation direction) is increased by that much, but the present invention is not limited to this, and the rigidity is improved by connecting the stiffener plate 12 made of a rigid material to the two convex portions 3. You may do so.

[0030]

According to the present invention, the structure of the cylinder head cover constructed as described above is employed.
Since the two convex portions are connected, the rigidity of the two convex portions in the swing direction (width direction) increases. For this reason, it is possible to suppress the two convex portions from exhibiting the swing mode due to the engine vibration, and accordingly, the vibration of the cylinder head cover is reduced, and the radiation noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a structure of a cylinder head cover according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view showing a structure of a cylinder head cover according to a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a plan view showing a structure of a cylinder head cover according to a third embodiment of the present invention.

FIG. 6 is a perspective view showing the connecting plate member of FIG. 5;

FIG. 7 is a plan view showing the connecting plate of FIG. 5;

FIG. 8 is a front view showing the connecting plate member of FIG. 5;

FIG. 9 is a side view showing the connecting plate of FIG. 5;

FIG. 10 is a plan view showing a structure of a cylinder head cover according to a fourth embodiment of the present invention.

11 is a sectional view taken along the line AA in FIG.

FIG. 12 is a sectional view taken along the line BB of FIG. 10;

FIG. 13 is a plan view showing a structure of a cylinder head cover according to a fifth embodiment of the present invention.

FIG. 14 is a plan view showing the stiffener plate of FIG.

FIG. 15 is a diagram showing frequency-vibration velocity level characteristics for the fifth embodiment of FIG. 13 and the related art.

FIG. 16 is a sectional view schematically showing an example of a conventional single cam type cylinder head cover.

FIG. 17 is a sectional view schematically showing an example of a conventional twin cam type cylinder head cover.

FIG. 18 is a plan view showing an example of a twin cam type cylinder head cover having a cam pulley cover.

19 is a sectional view taken along line AA in FIG.

FIG. 20 is a plan view showing an example of a twin cam type cylinder head cover having no cam pulley cover.

FIG. 21 is a side view (width direction) schematically showing a vertical vibration mode of a single cam type cylinder head cover.

FIG. 22 is a front view (longitudinal direction) schematically showing the vertical vibration mode in FIG. 21;

FIG. 23 is a side view (width direction) schematically showing a vertical vibration mode of a twin cam type cylinder head cover.

24 is a front view (longitudinal direction) schematically showing the vertical vibration mode of FIG. 23.

FIG. 25 is a side view (width direction) schematically showing the swing mode of the twin cam type cylinder head cover.

26 is a front view (longitudinal direction) of the swing mode of FIG. 25 shown corresponding to the vertical vibration mode of FIG. 24;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head cover 2 Head cover main body 3 Convex part 8 Rib (connecting member) 9 Bridge part (connecting member) 10 Connecting plate (connecting member) 11 Tube member (connecting member) 12 Stiffener plate (connecting member)

Continued on the front page (72) Inventor Makoto Sugiura 300 Takatsukacho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd. (72) Inventor Kenji 300 300 Takatsukacho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd. F-term (reference) 3G024 AA72 BA05 BA24 DA03 DA10 DA18 FA00 FA02 FA05 FA14 GA26

Claims (9)

[Claims] 1. A head cover body having a substantially rectangular shape in a plan view, and a longitudinally extending protrusion formed on both sides of the head cover body in the width direction so as to protrude from inside to outside.
A structure of a twin cam type cylinder head cover having two convex portions, wherein a connecting member for connecting the two convex portions is provided. 2. The structure of a cylinder head cover according to claim 1, wherein the connecting member is provided at a substantially central portion in a longitudinal direction of the head cover main body. 3. The structure of claim 1, wherein the connecting member comprises a plurality of connecting members arranged along a longitudinal direction of the head cover body. 4. The connecting member according to claim 1, wherein the connecting member is a plate-shaped rib suspended from the head cover body.
The structure of the cylinder head cover according to any one of the above. 5. The connecting member according to claim 1, wherein the connecting member is a bridge portion formed so as to bridge the two convex portions.
4. The structure of the cylinder head cover according to any one of items 3 to 3. 6. The cylinder according to claim 1, wherein the connecting member is a connecting plate member provided separately from the two convex portions so as to bridge the two convex portions. Head cover structure. 7. The structure of the cylinder head cover according to claim 1, wherein the connecting member is a cylindrical member. 8. The structure of the cylinder head cover according to claim 7, wherein the cylinder member also serves as a blow-by gas passage. 9. The cylinder head cover according to claim 1, wherein the connecting member is a stiffener plate made of a rigid material fixed to the two convex portions so as to cover an upper surface of the two convex portions. Construction.