JPH07127478A - Timing chain case structure for four-cycle engine - Google Patents

Abstract

PURPOSE:To facilitate maintenance of a chain tensioner and to mount a related part with high rigidity by a method wherein mating surfaces with a chain cover at the side of a cylinder block are formed so that a difference in a level therebetween is formed in the lateral direction of a cross section. CONSTITUTION:A timing chain case comprises the side of the cylinder block 15 of a four-cycle engine; and a chain cover 16 with which the side of the cylinder block is covered. In this case, mating surfaces 15a and 15b with the chain cover 16 situated to the side of a cylinder block 15 are formed such that a difference in a level therebetween is produced in the lateral direction of a cross section. A support part 15c to support a mounting part below an alternator is integrally protruded from the side of one mating surface 15a. Further, a mounting hole 15e for fixing a push rod cylinder is drilled below the support part 15c so that a push rod to push a tension arm 72a is maintainably installed from the outside.

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 timing chain case defined by a side surface of a cylinder block of a 4-cycle engine and a chain cover covering the side surface of the cylinder block.

[0002]

2. Description of the Related Art In a four-cycle engine, a timing chain (or a timing belt) for transmitting the rotation of a crankshaft to a camshaft of a valve at a constant ratio in order to open and close a valve arranged at the upper part of the engine. Therefore, on the side surface of the cylinder block, there is a sprocket fixed to the crankshaft,
A chain (or a toothed belt) for meshing with the sprocket and transmitting the rotation of the crankshaft to the camshaft above the engine is arranged.

The timing chain (hereinafter, the same applies to the timing belt) is also provided with a tensioner for preventing the chain from swinging and at the same time automatically adjusting the extension due to long-term use. A chain cover for covering the chain is attached to the inside of the case, and the chain is housed in a case defined by them, and the rotation of the crankshaft is further extended to the outside of the chain cover such as an alternator or a cooling fan. A pulley and a belt for transmitting to the rotating shaft are arranged.

[0004]

By the way, in the above-mentioned four-cycle engine, when the push rod cylinder of the tensioner is installed on the chain cover in order to enable maintenance of the tensioner from the outside, the mounting rigidity of the chain cover is reduced. In addition, the tensioner is directly affected by the swing of the chain cover due to engine vibration, as the relative positional relationship between the push rod supported on the chain cover side and the tension arm pivotally mounted on the cylinder block side becomes lower. There is a problem that it has a bad influence on the function of preventing the swing of the chain and automatically adjusting the elongation of the chain.

An object of the present invention is to eliminate the inconvenience of the conventional timing chain case of a four-cycle engine, and more specifically, the timing defined by the side surface of the cylinder block and the chain cover. The purpose of the structure of the chain case is to enable maintenance of the tensioner from the outside of the chain cover and to attach the push rod cylinder of the tensioner to the cylinder block with high rigidity.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems and to achieve the object, the present invention provides a timing chain case defined by a cylinder block side surface of a 4-cycle engine and a chain cover covering the cylinder block side surface. In the structure, the mating surface on the side surface of the cylinder block with the chain cover is formed so as to form a step in the left-right direction of the cross section.

[0007]

[Operation] According to the above configuration, the push rod cylinder is fixedly installed on the cylinder block so that the end of the cylinder block is outside the timing chain case on the side of the convex side of the mating surface. As a result, the tensioner can be maintained from the outside of the chain case regardless of the chain cover, and the push rod cylinder can be attached with high rigidity.

Since the push rod and the tension arm of the tensioner are installed on the cylinder block side, the vibration of the chain cover due to the vibration of the engine does not affect the relationship between the tensioner and the chain.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A timing chain case of the present invention will be described below with reference to the drawings by an embodiment of a multi-cylinder four-cycle engine of an automobile.

FIG. 1 shows the arrangement of accessories for the multi-cylinder engine when viewed from the direction of the cylinder row. In the vicinity of the engine 1, an alternator 2, a power steering pump 3, and an air conditioner compressor are provided. Accessories such as 4 are arranged, and the respective rotary shafts 21, 31, 41 for operating these accessories and the crankshaft 11 of the engine are the rotary shafts of the water pump 5 attached to the engine 1. Along with 51, it is configured so as to be interlocked by one belt 7 that is wound around each pulley 12, 22, 32, 42, 52 provided on each, and oil having a filter portion below the engine 1 A cooler 8 is attached.

FIG. 2 shows the engine 1 in FIG. 1, in which a cylinder head 14 provided with a head cover 13 on the top and a cylinder block 15 whose side surface is covered by a chain cover 16 (in this embodiment, this portion is (Comprising a cylinder block body and a crankcase), and an oil pan 17 installed below the cylinder block 15.
The timing chain case is defined between the side surface of the cylinder block 15 and the chain cover 16, and the water pump 5 is attached to the surface of the chain cover 16.

FIG. 3 shows a state in which the chain cover 16 is removed from the engine 1 shown in FIG.
On the side surface of the cylinder block 15, an inlet port 18 for introducing cooling water to the water pump 5 and an opening portion 19 for introducing cooling water to the water jacket of the cylinder block are opened above the side surface of the cylinder block 15. Oil passage 83 for introducing oil into the oil cooler 8
In the space defined by the timing chain case, the sprocket 60 fixed to the crankshaft 11 and the chain engaging teeth provided in parallel with the sprocket 60 mesh with each other. 61 and 62 are arranged.

The chain 61 is an intake camshaft 64 of a five-valve twin cam (not shown) having three intake valves and two exhaust valves per cylinder arranged in the upper part of the engine.
And a lower chain of a two-stage timing chain for transmitting the rotation of the crankshaft 11 to the exhaust camshaft 65 and rotating each camshaft 64, 65 by the upper chain 68 via the intermediate rotation shaft 67. The chain 62 is a rotary shaft 6 of an oil pump (not shown) installed in an oil pan 17 under the engine.
3 for transmitting the rotation of the crankshaft 11.

Each cam shaft 64, 6 of this twin cam valve
For the two-stage timing chain for rotating 5, the tensioner 71 is installed in the cylinder head 14 in the upper chain 68, and the tensioner 72 is installed in the cylinder block 15 in the lower chain 61 so that they can be maintained from the outside. Has been done.

The intake camshaft 64, the exhaust camshaft 65 and the intermediate rotary shaft 67 are arranged with respect to the center line passing through the crankshaft 11 in order to secure a space for installing the tensioner 71 in the cylinder head 14. The tensioner 71 is slightly displaced from the normal direction in the opposite direction.

Further, as shown in FIG. 2, when the side surface of the cylinder block 15 is covered with the chain cover 16, the outer surface of the chain cover 16 serving as the outer housing of the timing chain case has a turbine. The cover member 50 in which the respective parts for forming the housing 53, the cooling water passage 54 to the water jacket opening 19 and the cooling water passage 55 to the oil cooler 8 are integrated is fixed by bolts, so that the water A pump 5 is attached.

As shown in FIG. 5, the water pump 5 has a housing portion having a chain cover 1.
6 is integrally formed with the turbine housing 6, and the housing portion is covered with a cover member 50 to form a turbine housing 53 and cooling water passages 54 and 55 following the turbine housing 53. 5
7 will be installed, and the rotating shaft 51 of the turbine 57 will be installed.
Is extended to the outside of the cover member 50, and a pulley 52 for interlocking with the rotation of the crank shaft 11 of the engine 1 is attached to the tip of the cover member 50 to circulate the cooling water as shown in FIG. It is what makes me.

The cooling water passage 5 of the water pump 5
As for the inflow passage of the cooling water from the oil cooler 5 to the oil cooler 8, as shown in FIG. 6, from the end of the cooling water passage 55 formed by the chain cover 16 and the cover member 50 to the chain cover 16. Passed through passage 55b
The cooling water is introduced into the oil cooler 8 from the cooling water introduction part 81 of the oil cooler 8 via the.

The cooling water passage 55 to the oil cooler 8 of the water pump 5 is not limited to the one formed by the chain cover 16 and the cover member 50 as in the above embodiment, but is shown in, for example, FIG. As shown in FIG. 9, the cooling water passage 55 to the oil cooler 8 is integrally formed on the back side of the chain cover 16, or as shown in FIG.
By forming 5 on the cylinder block 15 itself, it is possible to integrally form the components of the engine without using a member such as a hose.

In any case, the mating surfaces 15a and 15b on the side surface of the cylinder block 15 with the chain cover are formed so as to have a step in the horizontal direction of the cross section, and the chain cover 16 portion on the mating surface 15b side is formed. Since the water pump 5 is formed, the water pump 5 does not project much from the side surface of the cylinder block 15 as compared with the case where the mating surface of the cylinder block side surface and the chain cover are formed flush with each other. Can be installed.

FIG. 9 shows a mount bracket 9 for fixing the engine 1 to the vehicle body and a mounting portion of the engine 1 for the mount bracket 9. The mount bracket 9 extends over both the cylinder head 14 and the cylinder block 15. The fixing portions 90a, 90b, 90 for fixing to the vehicle body mounting portion 91 and the respective portions 10a, 10b, 10c, 10d of the engine 1 by bolts.
c and 90d are provided, and the alternator 2
Fixing portion 9 for fixing the mounting portion 24 above the vehicle with bolts
Two are provided.

The alternator 2 has an upper mounting portion 24 fixed to the fixing portion 92 of the mount bracket 9 with a bolt, and a lower mounting portion 23 integrally formed on the cylinder block 15 to support the alternator. By being fixed to the fixing portion 15d of the portion 15c with the bolts, the engine 1 can be attached to the top and bottom of the portion as shown in FIG.

As a result, the lower mounting portion 23 of the alternator 2 has high mounting rigidity to the engine, and the upper mounting portion 24 is fixed to the vehicle body by the mount bracket 9, so that the vibration of the engine at that portion. The influence on the mounting state due to is reduced, and when the specification of the alternator 2 is changed, it can be dealt with by changing the mount bracket 9 accordingly.

In the engine 1 as described above,
As shown in FIG. 4, the mating surfaces 15a and 15b of the side surface of the cylinder block 15 with the chain cover are formed so as to have a step in the left-right direction of the cross section thereof. Face 15
A support portion 15c for supporting the mounting portion 23 below the alternator 2 is formed on the side of a so as to integrally project from the cylinder block 15.

Below the alternator support portion 15c, a push rod 72b for pressing the tension arm 72a of the tensioner 72 is installed on the cylinder block 15 from the outside, as shown in FIGS. 3 and 4. For this purpose, a mounting hole 15e for fixing the push rod cylinder 72C is formed through the cylinder block 15.

According to the above-described embodiment, the push rod cylinder 72c for accommodating the push rod 72b of the tensioner 72 has the mounting hole 1 formed in the thick portion below the alternator support portion 15c of the cylinder block 15.
Since it is fixed to the cylinder block 15e, the mounting rigidity of the portion is increased, and both the push rod 72b and the tension arm 72a of the tensioner 72 are attached to the cylinder block 15.
Since it is supported on the side, the swing of the chain cover 16 due to the vibration of the engine does not affect the relationship between the push rod 72b and the tension arm 72a.

Further, the tensioner 72 provided for the timing chain 61 is covered by the chain cover 16, but since the end of the push rod cylinder 72c projects outward from the timing chain case portion, the push rod 72b is provided. The maintenance can be performed from the outside without removing the chain cover 16.

Further, since the mating surfaces 15a and 15b on the side surface of the cylinder block 15 with the chain cover are formed so as to have a step in the horizontal direction of the cross section, they are formed on the chain cover 16 portion on the mating surface 15b side. The water pump 5 can be installed in such a state that it does not project much from the side surface of the cylinder block 15 as compared with the case where the side surface of the cylinder block and the mating surface of the chain cover are formed flush with each other.

Although one embodiment of the timing chain case structure of the four-cycle engine of the present invention has been described above, the present invention is applicable not only to the one using the timing chain but also to the one using the timing belt. Needless to say.

[0030]

According to the timing chain case structure of the four-cycle engine of the present invention as described above, the timing chain case defined by the side surface of the cylinder block and the chain cover can be maintained from the outside of the chain cover. The push rod cylinder of the tensioner can be attached to the cylinder block with high rigidity.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a side view showing an engine portion without accessories of the embodiment shown in FIG.

3 is a side view showing a state where a chain cover of the engine shown in FIG. 2 is removed.

FIG. 4 is a partial cross-sectional view taken along the line AA in FIG.

5 is a partial cross-sectional view taken along the line BB in FIG.

6 is a partial cross-sectional view taken along the line CC of FIG.

7 is an explanatory diagram showing a circulating state of cooling water by the water pump shown in FIG.

FIG. 8 is a side view of an engine portion showing another embodiment of the water pump.

FIG. 9 is a side view of an engine portion showing still another embodiment of the water pump.

FIG. 10 is an exploded side view showing a part of the mounting bracket of the embodiment shown in FIG. 1 and an engine for mounting the mounting bracket.

[Explanation of symbols]

1 Engine 15 Cylinder Block 15a Cylinder Block Aligning Surface with Chain Cover 15b Cylinder Block Aligning Surface with Chain Cover 16 Chain Cover

Claims (1)

[Claims] 1. A timing chain case defined by a side surface of a cylinder block of a four-cycle engine and a chain cover covering the side surface of the cylinder block, wherein a mating surface of the side surface of the cylinder block with the chain cover has a step in the lateral direction of its cross section. A timing chain case structure for a four-cycle engine, characterized in that it is formed to occur.