JPH0310363Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a structure for preventing the ingress of sewage into a belt cover of an engine. Specifically, by providing a buttful portion extending forward from the oil pan, the belt cover of the engine is provided with a buttful portion extending forward from the oil pan. This invention relates to a device for preventing infiltration of sewage into a belt cover that partially covers the belt cover.

[Conventional technology]

2. Description of the Related Art A timing belt that communicates with a crankshaft and a camshaft in an engine of an automobile or the like is desirably covered with a cover or the like to prevent foreign matter such as sewage or mud from adhering to it. That is, since the timing belt moves at high speed while the vehicle is running, foreign matter is likely to get caught between it and the sprocket. If such foreign matter gets caught, the sprocket and belt will be damaged, and the life of the belt will be significantly shortened. Furthermore, if moisture adheres to the belt, the belt will swell and its tensile force and strength will decrease, causing trouble in the interlocking operation between the crankshaft and the camshaft, or causing the belt to break. Particularly in cold regions, moisture adhering to the belt may freeze and the belt may no longer be able to perform its functions. Therefore, belt covers have conventionally been used to protect this timing belt portion. An example of such a cover device is
It is described in Japanese Utility Model Application Publication No. 52-42980.

[The problem that the idea attempts to solve]

For engines that have a pulley attached to the front of the sprocket that drives the above-mentioned timing belt with power from the crankshaft, the pulley is installed so that the pulley can drive the belt that operates the auxiliary equipment such as the water pump. The cover around the mounting part is cut out.

Therefore, it is not possible to provide a cover to cover the timing belt completely without any gaps, and the area that cannot be covered is the lower part of the engine, where sewage and mud splashed up while driving are trapped. It will seep into the interior from some parts. Particularly in engines where the sprocket that drives the timing belt is installed close to the seal flange of the oil pan, foreign matter such as sewage and mud can pass through the bottom of the oil pan and cause damage to the cylinder block, oil pump casing, and pulleys. It penetrates into the timing belt part through the small gap between the parts. As a result, as mentioned above, the sprocket and belt may be damaged, and the life of the belt may be significantly shortened.
Alternatively, a problem may occur in which trouble occurs in the interlocking operation between the crankshaft and the camshaft.

By the way, Japanese Utility Model Publication No. 55-172629 discloses that a protrusion is provided on the lower front surface of the cylinder block, the protrusion is formed into an upwardly opening circular arc, and the crankshaft sprocket on which the timing belt is stretched is attached to the circular arc. An engine that covers the lower half of the engine is described. Therefore, it is possible to cover approximately the lower half of the rear surface of the crank pulley on which the accessory drive belt, which is coaxially attached to the crankshaft sprocket, is stretched.

However, the arc-shaped protrusion is formed integrally with the engine body. Since the engine body is usually manufactured by casting, it is not easy to mold the protrusions mentioned above at the same time, and if they are integrally molded, the engine body will become relatively bulky and the weight of the engine body will increase. It gets bigger.
Therefore, the above-mentioned protrusion must be prepared as a separate part, which has the disadvantage of increasing the number of parts and the labor involved in assembling the engine, such as mounting and fixing the protrusion on the cylinder block or the like.

On the other hand, Japanese Utility Model Application Publication No. 52-90612 describes an example in which a flywheel provided at the rear of the engine body is covered by a wheel cover portion.
The wheel cover part is integrated into the crankcase. However, the flywheel itself is not connected to any other transmission system via a timing belt or the like, and the wheel cover does not require any cutout. Furthermore, the flywheel is provided at the rear of the engine body, and its positional conditions with respect to infiltration of sewage and foreign matter are much easier than for sprockets and pulleys that are provided at the front. Furthermore, since the wheel cover is formed separately and is integrated with the crankcase by bolting, bolt holes are required between the joint and the crankcase, and both joints must have sufficient strength. required. Therefore, the joint portions of both the wheel cover portion and the crankcase must be formed thick, which increases the weight, requires more processing steps, and increases costs.

This idea was created in view of the above-mentioned problems.
Its purpose is to prevent foreign matter such as sewage or mud from entering the timing belt from near the pulley attachment area in engines where the pulley is attached to the front of the crankshaft sprocket.
By preventing the engine body from becoming bulky or heavy, it is possible to reduce machining man-hours and reduce costs.Also, without the need for separate parts, the number of parts can be maintained and the labor of assembling the engine can be reduced. An object of the present invention is to provide a structure for preventing the infiltration of sewage into a belt cover of an engine, which can reduce the amount of water intrusion into the belt cover of an engine.

[Means to solve the problem]

In the present invention, a pulley is attached to the front surface of a sprocket that drives a timing belt, the sprocket is provided in the oil pan close to a sealing flange portion of the engine body side casing, and a belt cover that covers the timing belt is attached to the pulley. Applicable to engines that have a cutout at the periphery to expose the lower half of the sprocket.

Its characteristics are as shown in Figure 1.
A buttful portion 8 that covers at least the lower half of the rear circumference of the pulley 6 together with the sprocket 2.
However, the oil pan 5 near the sprocket 2
It extends forward from the seal flange portion 5a and is formed in a semicircular arc shape.

[Effect]

A semi-circular buttful part is formed to extend forward of the oil pan and cover the circumference of the rear side of the pulley.This buttful part allows foreign substances such as sewage and mud to escape from the gap at the bottom of the oil pan. Infiltration is prevented. As a result, the timing belt will not swell, and foreign matter will not get caught between the timing belt and sprocket, which will prevent damage to the sprocket and timing belt, as well as problems with the interlocking of the crankshaft and camshaft. Ru. Furthermore, the buttful part is integrated with the oil pan, which reduces the number of parts and the associated assembly effort.

[Effect of idea]

According to the present invention, when a pulley is attached to the front of an engine such as an automobile and a sprocket for driving a timing belt is provided close to a seal flange of an oil pan,
Since a buttful portion is provided that extends forward from the oil pan and covers at least a portion of the circumference on the rear side of the pulley, this buttful portion prevents foreign matter from entering the interior from the portion where there is no belt cover. I can do it. Further, the buttful portion is integrated with the oil pan, and no separate parts are required, so that the engine body does not become bulky or heavy. Therefore, the number of man-hours for machining the cast product of the engine body is also reduced, and costs can be reduced. Furthermore, the effort required to assemble the engine can be reduced, which is extremely useful in practice.

〔Example〕

The present invention will be described in detail below based on examples thereof.

As shown in FIGS. 1 and 2, a sprocket 2 for driving a timing belt 1 is fixed to a crankshaft 3, and an oil pump 4 is provided adjacent to and surrounding the crankshaft 3. An oil pan 5 is provided at the bottom of the oil pump 4,
Lubricating oil stored in an oil pan 5 is supplied to the engine by an oil pump 4. On the front surface of the sprocket 2, a pulley 6 for driving auxiliary equipment such as a water pump 16 (see FIG. 4) is fixed to the crankshaft 3 integrally with the sprocket 2.

In order to seal the oil pan 5, a seal flange 5a is formed at the front end of the oil pan 5, and a seal member 7 is interposed between the oil pan 5 and the casing 4a of the oil pump 4. This casing 4
A is formed into a substantially semicircular arc shape so as to surround the lower half of the sprocket 2, and a seal flange portion 5a at the front end of the oil pan 5 extends forward.

A semicircular arc-shaped buttful portion 8 is formed along and surrounding the casing 4a and so as to at least partially cover the circumference of the boss portion on the rear side of the pulley 6. This semicircular arc-shaped buttful portion 8 forms a gap S between the casing 4a of the oil pump 4 and the back plate 9 provided on the back surface of the pulley 6.
It wraps around the area from below. A belt cover 10 that covers the timing belt 11 has a semicircular arc edge 10b such that its lower end surrounds the upper half of the boss portion of the pulley 6.

The above timing belt 1 is shown in FIGS. 3 and 4.
As shown in the figure, the lower part is suspended over a sprocket 2 fixed to the crankshaft 3, and the upper part is suspended over a sprocket 12 fixed to the camshaft 11 of the engine. They are linked at a ratio of 1:2. Note that 13 in the figure is a tension pulley.

The belt cover 10 described above is disposed so as to cover the timing belt 1.
0 consists of an upper cover 10A forming an upper half and a lower cover 10B forming a lower half, as shown in FIG. The upper cover 10A completely covers the portion of the timing belt 1 that is stretched over the sprocket 12, and is provided along each of the casings of the head cover 14, cylinder head 15, and water pump 16, as shown in FIG.

The lower cover 10B is continuous with the upper cover 10A and covers the timing belt 1 from the water pump 16 to the oil pump 4 and the lower edge 17a of the half skirt forming the lower part of the cylinder block 17. This lower cover 10B surrounds the upper half of the back circumference of the pulley 6 attached to the front surface of the sprocket 2, and its lower end forms a semicircular arc edge 10b as described above. Therefore, the lower half of the timing belt 1 stretched over the sprocket 2 is not covered by the lower cover 10B and is exposed. This is stretched around a pulley 6 attached to the front of the sprocket 2.
This is so that the belt 18 for operating auxiliary equipment such as the water pump 16 can be driven.

The timing belt 1 is always driven by the sprocket 2 while the engine is rotating, and has an important role of interlocking the rotation of the crankshaft 3 with the camshaft 11. In particular, since the timing belt 1 is driven at high speed while the engine is running, the sprocket It is easy for foreign objects to get caught between 2 and 12. Therefore, in this example, as mentioned above,
The front of the seal flange 5a at the front end of the oil pan 5 is extended, and the casing 4 of the oil pump 4
A semi-circular buttful portion 8 is formed to surround the pulley 6 along the direction a and to cover the rear circumference of the pulley 6.
It is provided so as to wrap around and cover the gap S created between the pulley a and the back plate 9 provided on the back surface of the pulley from below.

Therefore, the buff-full portion 8 prevents foreign matter such as sewage and mud from entering the gap S from the lower part of the oil pan 5, as well as powdered snow flying under the vehicle body. As a result, foreign objects are no longer caught, which can damage the sprockets 2 and 12 and the timing belt 1, significantly shortening their lifespan, or cause trouble in the interlocking operation between the crankshaft 3 and camshaft 11. things won't happen.

In addition, in the above-mentioned example, the cylinder block and oil pan are joined to each other almost at the center of the crankshaft, and the seal flange at the front end of the oil pan faces the casing of the oil pump.
If the oil pump is not provided at that location, the seal flange may face the lower end surface of the cylinder block, and the same function can be achieved in that case as well. With this structure, there is provided something that extends forward from the oil pan and covers the circumference of the rear side of the pulley, so that the intended purpose can be achieved.

As can be seen from the explanation of the above examples, foreign matter that tries to enter the interior from the part where there is no belt cover is
This can be prevented by the buff-full portion. The buttful portion is integrated with the oil pan, and can prevent the engine body from becoming bulky or heavy. Therefore, the number of man-hours required for machining the cast product of the engine body can be reduced, making it possible to reduce costs. In addition, since no separate parts are required, the effort required to assemble the engine can be reduced.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the main parts of an embodiment of the engine belt cover sewage infiltration prevention structure of the present invention;
The figure is a front view showing the main parts with the pulley removed, Figure 3 is a front view of the timing belt attachment part,
FIG. 4 is a sectional view of the belt cover in an attached state, and FIG. 5 is a front view of the belt cover. 1... Timing belt, 2... Sprocket, 5... Oil pan, 5a... Seal flange section, 6... Pulley, 8... Buttful section, 10...
belt cover

Claims (1)

[Claims for Utility Model Registration] A pulley is attached to the front of a sprocket that drives a timing belt, and the sprocket is provided close to a sealing flange of an oil pan against a casing on the side of the engine body,
In an engine in which the belt cover that covers the timing belt is cut out at the periphery of the pulley and the lower half of the sprocket is exposed, the belt cover covers at least the lower half of the rear circumference of the pulley together with the sprocket. The department is
A sewage ingress prevention structure for an engine belt cover, characterized in that the belt cover is formed in a semicircular arc shape and extends forward from a seal flange portion of an oil pan adjacent to the sprocket.