JP2005344699A - Separate type timing case (with cam chain and tensioner in one unit, timing belt and tensioner in one unit or built-in cam gear) - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine easy to disassemble, assemble and check. <P>SOLUTION: The timing case with the external engine, in which a timing chain, a belt or a gear is formed in one unit with a tensioner or a dislocation preventing device, is constructed to be easy to demount. It is of a set-in type to be easy to align when mounted. Thus, the dislocation is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an engine structure for simplifying assembling / disassembling of automobiles, motorcycles, etc., and performing work efficiently.

In the conventional engine structure, the chain or gear connecting position between the crankshaft and the camshaft is located in the engine, so it is necessary to provide a chain or gear passage inside the cylinder or cylinder head (especially for motorcycles). In addition, since it is necessary to provide a space for installing the cam chain tensioner in the engine, a single component tends to be large.
Further, when replacing the cam chain, there are many cases in which the crankshaft is removed, and it is not easy to disassemble the engine.

Hereinafter, the structure of a general engine (motorcycle) will be described as an example.
In FIG. 1, the cylinder structure of a general motorcycle 4-cylinder engine will be described. A side cam chain system is adopted in which the cam chain passes through the rightmost short in the case of this vehicle type. [Fig. 2] employs a method in which the cam chain passes through the center portion in the same manner, although it has four cylinders. FIG. 3 shows the simplest cam chain position of a single cylinder engine. (All are based on data from Honda Motor Co., Ltd.) Here, what is common in structure is that the passage of the cam chain is provided inside the engine.

  The conventional engine has a long structure that requires a long space from the crankcase to the cylinder head to pass the cam chain and cam gear. Particularly in heavy-weight multi-cylinder engines, increasing the crankcase width alone has led to considerable weight gain. In the case of a two-wheeled vehicle engine, there are many parts that need to be replaced due to an abnormal noise at the cam chain / tensioner interference part. However, since the replacement is not easy, the work cost is high. Also, minor problems such as oil bleed cannot be easily corrected. If the cam and crank can be connected more simply, maintainability will be improved to the same level as two cycles.

The purpose of the present invention is to make the cam chain (drive part of cam gear, timing belt, etc.) and the tensioner part an integral structure, which can be easily removed by external attachment, and to facilitate disassembly, replacement and assembly. As a result, it aims to further improve high output and low fuel consumption by simplifying and reducing the weight of the conventional engine structure.
In addition, it is possible to reduce the repair cost by improving maintainability, and by reducing the vehicle maintenance cost, anyone can easily receive maintenance, and as a result, aims to improve safety and comfort. is there.

Means to solve the problem

  Conventionally, many camshafts are equipped with a sprocket for the cam chain near the large end of the crankshaft ([FIG. 4]), but the chain cannot be replaced when the crankcase is closed. There is a side cover chain type with the cam chain arranged on the outermost side, and some external vehicles use timing belts, but all have a structure that must be disassembled into single parts when the engine is disassembled ( [FIG. 5]). In the present invention, the cam chain sprocket and the cam gear, which are normally arranged in the crankcase, are integrated with the tensioner device to be fitted into the outside of the crankcase.

  Regardless of the cam chain, cam gear, or timing belt, integrating with the tensioner unit eliminates the need for timing adjustment that has been troublesome in conventional assembly. This timing case, which can be easily attached and detached with a one-touch tension release device, has a structure with a subtensioner or guide that prevents the internal timing from shifting, and there is no displacement inside the case. A structure that only fits the alignment mark.

Since it is an external structure, oil lubrication is required for chain gear drive except for the belt, so one of the following structures shall be adopted.
1. Lubricate with part of engine oil lubrication (camshaft center hole or oil through bearing). (Type with dedicated lubrication path)
2. Type with oil pool in separate tensioner case. (With drain, level gauge or level window, filler port)
3. Type with only dry grease-up holes. (Chain grease only)
All shall be equipped with appropriate packings and seals, and shall be sealed except for the tube path that releases the thermal expansion pressure to the outside. (For oil bias prevention and noise reduction)

The invention's effect

  Engines can be broadly divided into the following five groups according to the structure in which each major part is divided into blocks ([Figure]). As a result, the number of blocks has been increased by one compared to the conventional type, and until the cylinder head is assembled, there is no need to assemble a timing chain, tensioner, slipper, etc. The size of the cylinder head can be made as small as two cycles and the weight can be reduced. Naturally, the working time can be reduced to less than half.

  Gaskets such as deterioration due to aging, deformation due to thermal expansion, etc., oil leakage of packings, repair of bleeding, repair of engine noise, and repair of engine noise are easy to check and check due to improved maintainability. Not only can it be done, but also the main components (parts exposed to high heat, etc.) can be reduced, contributing to the reduction of problems such as oil leaks.

Hereinafter, the structure will be described with reference to the drawings.
FIG. 7 illustrates a cam chain system and a belt drive structure. In FIG. 8, cam gear driving is described.
The structure of the engine body for attaching the timing case is shown in FIG. It is necessary to project the drive gear on the crank side and the shaft for driving the camshaft.
It should be noted that when this timing case is fitted to the engine side, an example of a structure that is aligned with a positioning mark or a special shape so that the cam timing is aligned with a one-touch structure is shown.

    Exploded view of water-cooled four-cylinder engine with side cam chain     Structure diagram of center cam chain type water-cooled four-cylinder engine     Exploded view of single cylinder engine     Diagram showing the structure of the crankshaft and cam chain of a typical water-cooled engine     Structural diagram on the camshaft side of a side cam chain engine     Comparison between the conventional type and the improved type (viewed from the back)     Comparison of conventional and improved models (view from above)     View from the side of the integrated timing case of the present invention (cam chain system)     View from the side of the integrated timing case of the present invention (cam gear system)     The figure showing the structure of the camshaft and crankshaft or crank side drive part for making an integrated timing case attachment easy.     Structure diagram for each system for oil lubrication of the chain or gear in the timing case.

Explanation of symbols

Fig.7-a Inlet cam sprocket (cam gear)
b Exhaust side cam sprocket (cam gear)
c Cam chain (same for belt drive)
d Cam chain tensioner and slider e Cam chain tensioner and slider f Upper cam chain tensioner (Sub-tensioner to prevent misalignment of a and b sprockets when the integral tensioner case of the present invention is attached / detached)
g Crank side (drive side) meshing gear h Timing case meshing gear j Structure that allows tensioner adjustment from the side of the case k Packing (for preventing oil leakage at the mating part)
Fig.8-a Intake side cam gear b Exhaust side cam gear c Cam drive gear d Crank driven gear e Crank gear f Packing

Claims (4)

  In automobile and motorcycle engines, the drive part that determines the valve timing of intake and exhaust is integrated with a removable cassette type, so that it does not pass through the cylinder or cylinder head so that it takes time to disassemble and assemble the engine. Structure to dramatically improve (cam chain, integrated type with belt tensioner function, separate type timing case). An engine having that structure.   It has a function to easily release tension of the tensioner when the cassette of the drive part is attached / detached. At that time, it has a function to prevent misalignment of the cam chain, timing belt, etc. (sub-tensioner or misalignment prevention guide Timing case.   When installing this cassette type timing case, it must have a positioning mark that makes positioning easy on the output shaft side and the valve side, or a matching part with a special shape.   For the chain lubrication method when the drive method is a chain or gear, one of the three methods of the oil supply method from the engine side, the completely separate oil pool method, and the grease up method from the outside is adopted .

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