JPH094464A - Internal combustion engine - Google Patents

Abstract

PURPOSE: To secure a large quantity of mass inside of the same space by enlarging the semi-circular outline of a balance weight out of the circular of both skirt parts so that the constant minimum clearance between a piston, a cylinder liner and the balance weight can be secured during the time when the balance weight between the specified angles is coming close to near the upper dead center of a rotating crank. CONSTITUTION: The narrowest clearance (k) formed between a central lower part 2a of a piston 2 and a central part 1b of a balance weight 1 can be maintained even between shoulder parts and the lower end 2b of both ends of the piston 2, and furthermore, even in the case where the balance weight is turned and a projecting expanded part 1a achieves the clearance part, the narrowest clearance can be maintained. Furthermore, even in the case where a crankshaft 4 is turned, the narrowest clearance can be maintained between the lower ends 2b of both ends and the projecting expanded part 2b. The projecting expanded parts 1a are formed in both skirt parts of the balance weight 1. With this structure, in comparison with the conventional balance weight, a larger balance weight can be secured in the same space.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in an internal combustion engine such as a diesel engine, makes the shape of the balance weight large without massing the space and improves the shape of the push rod, valve arm chamber and oil pan. It is a thing.

[0002]

2. Description of the Related Art The prior art for the invention of claim 1 is shown in FIGS. 5 and 6 as disclosed in, for example, Japanese Patent Laid-Open No. 61-248936. That is, conventionally, with the rotation of the crankshaft 4, the balance weight 1 '
It was known that the gap between the cylinder 3 and the piston 2, which are the interferences, changed little by little, but it was a troublesome work to calculate the change and draw it in a drawing. For ease of design, the arc was set to have the center of the crankshaft 4 as the center position. In this case, the gap was changed with the rotation of the crankshaft 4, and a useless gap was generated more than necessary.

The prior art for the invention of claim 2 is shown in FIG.
1 is shown. That is, in the conventional balance weight, the corner recess 11a on the balance weight 11 side, which corresponds to the corner 5b of the balance weight mounting seat 5a protruding from the crankshaft, has two small radius arcs and a straight line connecting them. It was constituted by the combination of. In the case of this configuration, since it is a combination of a plurality of shapes, it cannot be said that the structure is simple. When the mass of the arm portion 11c of the balance weight 11 becomes large, the inertial force cannot be endured due to its strength, and cracks occur. Further, conventionally, there is also a structure in which the corner recess 11a is not provided. In this case, since the size and shape of the balance weight 11 are limited,
The mass of the balance weight could not be increased.

The prior art for the invention of claim 3 is shown in FIG.
As shown in FIG. 3, there is a structure in which the roller tappet 10 is arranged right above the camshaft 8 and the center line of the vertical reciprocation of the roller tappet 10 passes through the center of the camshaft 8. For example, it is like the technique described in Japanese Patent Laid-Open No. 7-54616. However, in this case, since the distance between the air supply valve or the exhaust valve and the push rod becomes wide, the air supply valve arm or the exhaust valve arm becomes long and the valve arm chamber 28 becomes large. It was. Further, as shown in FIG. 14, in the case of the conventional technique, there is a method of separately providing the swing arm 15 to absorb the gap generated between the push rod and the cam shaft. Since the number of parts of the arm 15 is increased, there is a problem that the number of parts is increased. Further, there is a conventional technique as shown in FIG. In this case, the roller tappet 10 is configured to reciprocate up and down on an inclined line passing through the center of the camshaft 8. However, in the case of this conventional technique, since the hole of the tappet guide 16 and the roller tappet are inclined, there is a problem that the cost is increased due to the processing of the inclined hole.

The prior art for the invention of claim 4 is the technique described in Japanese Examined Patent Publication No. 3-72833, and FIG.
There was a technique as disclosed in 8. However, in the case of the above conventional technique, the position of the supply / exhaust valve, the position of the push rod, the position of the fuel injection pump, etc. are preferentially determined, and the supply / exhaust valve arm then connects the dots. Therefore, the setting procedure has been performed in which the shape is determined. Therefore, the air supply valve arm 12 and the exhaust valve arm 22 have completely different shapes, and there is no idea that they are commonly used.

As the prior art for the invention of claim 5, there is the prior art as shown in Japanese Utility Model Publication No. 34-17512 and as shown in FIG. However, in the prior art, the capacity of the oil pan is inevitably small, and if the capacity of the oil pan 18 is increased, the height of the oil pan 18 increases and the overall height of the internal combustion engine increases. It was. Further, the bolt 2 for fixing the oil pan 18 and the cylinder block B together.
Since 3 is screwed from the lower side to the upper side, there is a problem that the assembling work is difficult.

[0007]

According to the present invention of claim 1, the piston 2, the cylinder 3 and the balance weight 1 are provided.
The gap between and is determined in detail over the rotation of the crankshaft 4, and is the narrowest gap k at all rotation angles of the crankshaft 4.

According to the second aspect of the present invention, the shape of the corner recess 11a of the balance weight 11 is simple and compact, and even if the mass of the arm portion 11c of the balance weight 11 is large, it is cracked. It is configured to prevent the occurrence of. Further, the size and shape of the balance weight 11 are not limited by this configuration, and the mass of the balance weight is increased.

According to the third aspect of the invention, the space between the air supply valve or the exhaust valve and the push rod is reduced to reduce the valve arm chamber. Further, the space between the air supply valve arm 12 or the exhaust valve arm 22 and the push rod 14 is made small without requiring any separate parts such as the swing arm 15. In addition, the hole of the tappet guide 16 that is processed diagonally,
It is configured so that the roller tappet 36 that obliquely moves up and down is unnecessary.

In the invention of claim 4, the air supply valve arm 12
By making the parts of the exhaust valve arm 22 and the exhaust valve arm 22 have the same shape,
This is to reduce the number of parts.

In the invention of claim 5, the oil pan 1
8 is increased, but the height of the internal combustion engine is not increased, and the cylinder block B and the oil pan 1 are
It is easy to assemble and disassemble with 8 by screwing the bolt 23 from above.

[0012]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. According to the first aspect, in the balance weight fixedly mounted on the crankshaft of the internal combustion engine, even if the crankshaft rotates, the balance weight is within ± 90 degrees before and after top dead center.
While the balance weight is approaching, the outer shape of the semicircular arc portion of the balance weight is expanded outside the arc so that the minimum clearance between the piston and the balance weight and between the cylinder liner and the balance weight is constant. It has a curved shape.

According to another aspect of the present invention, the balance weight fixedly mounted on the crankshaft of the internal combustion engine is fixed to the balance weight mounting seat protruding from the crankshaft. The corner recess for avoiding the interference with is formed by cutting a circular arc shape having an arc having a large radius.

In the third aspect, the camshaft is supplied and
With the configuration that the valve arm and the camshaft, which are located lower than the exhaust valve and are located above, are connected by a push rod, make the roller tappet that contacts the cam on the camshaft eccentric from the center of the camshaft. The roller tappet is reciprocated on a center line parallel to the cylinder center.

In the present invention, the camshaft is supplied and
In a configuration in which the valve arm and the cam shaft, which are arranged at a position lower than the exhaust valve and are arranged above, are connected by a push rod, the cam position on the cam shaft is set to
The exhaust cam and the fuel cam are arranged in this order, and the valve arm shaft is arranged in parallel with the cam shaft, so that both the intake valve arm and the exhaust valve arm can be used.

According to a fifth aspect of the present invention, at the mounting portion of the cylinder block and the oil pan of the internal combustion engine, an oil pan mounting seat projecting from the outer surface of the cylinder block is provided in the lower portion of the cylinder block, and the upper surface of the oil pan is provided. Also,
Provide the cylinder block mounting upper plate, and insert the bolt from the upper surface of the oil pan mounting seat on the cylinder block side,
It is screwed to the cylinder block mounting upper plate on the oil pan side.

[0017]

Next, the operation will be described. According to the invention of claim 1, in one revolution of the crankshaft, the narrowest gap k between the balance weight and the interfering substances such as the cylinder 3 and the piston 2 at the angle of each crankshaft 4 is made substantially constant.
It is possible to secure a larger mass in the same space as compared with the conventional balance weight. Further, it becomes possible to secure the largest mass of the balance weight in the crank space of the limited space, and the outer peripheral shape of the balance weight can be made compact. Further, it is possible to secure a large mass of the balance weight in the limited space of the crank chamber by using the same material.

According to the second aspect of the present invention, the shape of the corner recess 11a of the balance weight 11 is changed to the balance weight 1
The inner fixed seat 11b of No. 1 and the balance weight mounting seat 5a protruding from the crankshaft are in contact with a line one step lower than the joining surface, and are formed into an arc of a large radius that passes through the end of the mounting surface. 1 is more on the joint surface than on the tangent line
Since it is stepped, it is easy to process the surface of the inner fixed seat 11b. Further, it is possible to avoid interference between the corner portion 5b of the balance weight mounting seat 5a protruding from the crankshaft and the corner recess 11a. Also, the corner recess 1
It is also possible to improve the strength against cracking in the portion 1a. Also, the weight of the balance weight can be maximized in a minimum space. As a result, by increasing the mass of the balance weight, the efficiency of canceling the vibration of the internal combustion engine is improved. Further, with respect to the mass of the balance weight thus increased, it is possible to form the corner recess 11a in which cracking does not occur.

According to the third aspect of the present invention, the push rod 14 is eccentrically arranged on the center side of the cylinder block B, the intake valve arm 12 and the exhaust valve arm 22 are downsized, and the valve arm chamber 28 is formed. Is generated. In addition, it is not necessary to provide separate parts such as the swing arm 15,
This avoids an increase in the number of parts and contributes to cost reduction. Further, since the roller tappet 36 is slanted with respect to the center line of the cylinder block B and moves up and down, it is not necessary to machine the guide hole of the tappet guide 16 and the machining is facilitated.

According to the invention of claim 4, in the internal combustion engine, the intake valve arm 12 and the exhaust valve arm 22 can be used as the same component. As a result, the number of parts can be reduced, the cost can be reduced, and the mistake in assembling the internal combustion engine can be prevented.

According to the fifth aspect of the invention, the amount of lubricating oil in the oil pan 18 can be increased without increasing the height of the internal combustion engine. Further, since the bolt 23 can be screwed from above, assembly and disassembly is facilitated.

[0022]

EXAMPLES Next, examples will be described. FIG. 1 is a front view showing a structure of the present invention in which both hem portions of a balance weight 1 formed in a semi-arcuate shape are inflated and projected more than a semicircle, and FIG. 2 is a shoulder of the balance weight 1 when the crankshaft 4 rotates slightly. The front view of the state in which the narrowest gap k is formed between the portion 1c and the lower end portions 2b of both ends of the piston 2, FIG. 3 shows that the crankshaft 4 further rotates,
The front view of the state where the narrowest gap k is formed at the position 1d just before the projecting expansion part 1a, FIG. 4 is the front view of the state where the narrowest gap k is formed in the projecting expansion part 1a, and FIG. FIG. 6 is a front view of the balance weight 1 ′ of the conventional balance weight 1 ′ having a semicircular arc shape along the circumference. FIG. 6 shows the conventional balance weight 1 ′ having the narrowest gap k between the shoulder portion 1 c and the lower end portions 2 b of both ends.
It is a front view of the state which rotated to the position which comprises.

The invention of claim 1 will be described in detail with reference to FIGS. The piston 2 is fitted inside the cylinder 3 and slides up and down. The vertical movement of the piston 2 due to the explosive combustion is converted into the rotational force of the crankshaft 4 by the piston pin 6 and the connecting rod 7. A portion of the crankshaft 4 to which the connecting rod 7 is pivotally connected is eccentric with respect to an axis of the crankshaft 4 on which the bearing is supported, and a balance weight mounting seat is provided on a side opposite to the connecting portion of the connecting rod 7. 5a is provided. The inner fixed seat of the balance weight 1 is brought into contact with the surface of the balance weight mounting seat 5a and fixed by a bolt.

Conventionally, as shown in FIGS. 5 and 6, the balance weight 1 is constructed with a perfect circle centering on the crankshaft 4 as the outer circumference. But in this case,
As shown in FIG. 6, when the crankshaft 4a at the portion where the connecting rod 7 is pivoted about the shaft center of the crankshaft 4, the center of the balance weight 1 is the center of the crankshaft 4, but the connecting rod 7 Since the pivot portion is the crankshaft 4a, the rising speed of the piston 2 is different, and the gap between the central lower portion 2a of the piston 2 and the outer circumference of the balance weight 1 is not constant. Conventionally, it has been difficult to calculate all the change in the gap amount between the movement amount of the piston 2 and the outer circumference of the balance weight 1, so that an arc centered on the crankshaft 4 is simply provided. As a result, the balance weight 1 was designed. In the present invention, the gap between the crankshaft 4 and the outer circumference of the balance weight 1 can be calculated in detail at all positions by using a design method by a computer, and accordingly, the narrowest gap is obtained. The gap k is configured to be maintained at all positions.

According to such a design, as shown in FIG.
The narrowest gap k formed by the lower central portion 2a of the piston 2 and the central portion 1b of the balance weight 1 can be maintained between the shoulder portion 1c and the lower end portions 2b of the piston 2 as shown in FIG. As shown in FIG. 3, the narrowest gap k can be maintained even when it further rotates to reach the position 1d just before the protruding inflating portion 1a. Further, the crankshaft 4 is further rotated so that the narrowest gap k is formed between the lower end portions 2b on both ends and the projecting expansion portion 1a as shown in FIG. When designed for such a purpose, the protruding inflated portions 1a are formed at both hem portions of the balance weight 1 from the conventional round shape.

FIG. 7 shows an inner fixed seat 11b of the balance weight 11 for fixing the balance weight 11 fixed on the crankshaft of the internal combustion engine to the balance weight mounting seat 5a protruding from the crankshaft. FIG. 8 is a front view showing a shape in which a corner recess 11a for avoiding interference with the corner of the balance weight mounting seat 5a is cut into an arc shape having an arc having a large radius.
Is a front view showing a state where the inner fixed seat 11b of the balance weight 11 is fixed to the balance weight mounting seat 5a of the crankshaft 4, FIG. 9 is a front view showing a state where the balance weight 11 is processed by the machine tool M, and FIG. The corner recess 11a
FIG. 11 is an enlarged view of a shape obtained by scooping out an arc shape configured by an arc having a large radius, FIG.
FIG. 6 is an enlarged view of a configuration in which a shape having two small radii is scooped out.

Next, the invention of claim 2 will be described with reference to FIGS. 7 to 10. Conventionally, as shown in FIG. 11, an arc having a small radius r2 and an arc having a small radius r1 are connected by a straight line portion s to form a corner recess 11a. On the other hand, in the present invention, the shape of the corner recess 11a of the balance weight 11 is set to be more than that of the joint surface between the inner fixed seat 11b of the balance weight 11 and the balance weight mounting seat 5a protruding from the crankshaft. Touch the lower line,
It is configured as an arc having a large radius that passes through the end of the mounting surface.

With this structure, since the joint surface is one step higher than the tangent line of the arc, the inner fixed seat 11
This makes it easy to machine the b-side. In addition, the corner portion 5b of the balance weight mounting seat 5a protruding from the crankshaft,
It is possible to avoid interference with the corner recess 11a. Further, it is possible to improve the strength against cracking in the corner recess 11a. Thereby, the mass of the balance weight can be maximized in the minimum space. Also,
By increasing the mass of the balance weight, the efficiency of canceling the vibration of the internal combustion engine is improved. Further, with respect to the mass of the balance weight thus increased, it is possible to form the corner recess 11a in which cracking does not occur.

In FIG. 12, the camshaft 8 is connected to the supply / exhaust valve 1.
In a configuration in which the valve arm 12 and the cam shaft 8 disposed above the cam shaft 8 are connected to each other by a push rod 14, the roller tappet 10 that contacts the cam 9 on the cam shaft 8 is connected to the cam. FIG. 13 is a conventional cross-sectional view showing a configuration in which the roller tappet 10 is eccentric from the center of the shaft 8 and reciprocates on a center line parallel to the center of the cylinder 3. FIG. FIG. 14 is a front sectional view showing a structure in which the centers of FIG.
The center of the camshaft 8 and the center of the roller tappet 10 are eccentric to each other, and a front sectional view showing a structure in which a swing arm 15 is interposed in order to fill a gap therebetween, and FIG. 15 is a view showing another conventional technique. FIG. 7 is a front enlarged cross-sectional view showing a configuration in which the roller tappet 10 and the balance weight 11 are arranged toward the center of the camshaft 8, the tappet guide 16 is obliquely processed, and the roller tappet 36 is fitted in the hole. .

Next, the invention of claim 3 will be described with reference to FIGS. 12 to 15. In the present invention, the camshaft 8 is arranged in the camshaft chamber 26 provided inside the cylinder block B. The camshaft 8 includes
An air supply cam 9, an exhaust cam, and a fuel cam are provided in a protruding manner, and a roller tappet 10 is abutted on each cam.
The vertical movement by the cam of the roller tappet 10 is transmitted to the air supply valve arm 12 and the exhaust valve arm 22 in the valve arm chamber 28 by the push rod 14.

In the present invention, the roller tappet 10
And the center of the camshaft 8 are eccentric by a distance T. The push rod 14 itself that connects the roller tappet 10 and the air supply valve arm 12 is arranged in an inclined state, but the roller tappet 10 itself arranges the tappet guide 16 and the roller tappet 36 in parallel with the cylinder 3. By doing so, it is configured to move up and down on a line parallel to the cylinder 3. Therefore, the tappet guide 16, the roller tappet 36, and the push rod 14 are arranged in an angled state.

In FIG. 16, the supply / exhaust valve is arranged in parallel with the direction of the camshaft, the cam positions on the camshaft are arranged in the order of the supply cam, the exhaust cam, and the fuel cam, and the valve arm shaft 17 is cammed. A plan view of the air supply valve arm 12 and the exhaust valve arm 22 showing a configuration in which the air supply valve arm 12 and the exhaust valve arm 22 are arranged in parallel with the shaft, and FIG. FIG. 18 is a plan view of the valve arm 12 and the exhaust valve arm 22, and FIG. 18 is a plan view of the intake valve arm 12 and the exhaust valve arm 22 showing another conventional technique.

The invention of claim 4 will be described with reference to FIGS. Conventionally, as shown in FIGS. 17 and 18, the intake valve arm 12 and the exhaust valve arm 22 are formed in completely different shapes. However, in the present invention, as shown in FIG. 16, the air supply valve arm 12 and the exhaust valve arm 22 are made to completely coincide with each other. Further, the valve arm shafts 17 of the air supply valve arm 12 and the exhaust valve arm 22 are arranged in parallel with the direction of the cam shaft 8, and the cam positions on the cam shaft are arranged in the order of the air supply cam 9, the exhaust cam, and the fuel cam. are doing. As a result, the air supply valve arm and the exhaust valve arm can be used in common.

FIG. 19 is a top view of the oil pan 18 in which an oil pan mounting seat 20 projecting from the outer surface of the cylinder block B is provided in the lower portion of the cylinder block B at the mounting portion of the cylinder block B and the oil pan 18. Also,
The cylinder block mounting upper plate 19 is provided, and the bolt 2 is attached from the upper surface of the oil pan mounting seat 20 on the cylinder block B side.
20 is a front sectional view showing a configuration in which 3 is inserted and screwed into the cylinder block mounting upper plate 19 on the oil pan 18 side, FIG.
[FIG. 8] is a front sectional view showing a fixed portion between a conventional oil pan 18 and a cylinder block B.

The invention of claim 4 will be described with reference to FIGS. 19 and 20. In the present invention, the support foot 21 is separately projected from the cylinder block B. The oil pan mounting seat 20 projects from the lower portion of the cylinder block B toward the outer surface of the cylinder block B. A cylinder block mounting upper plate 19 projects from the oil pan 18 below the oil pan mounting seat 20. A bolt 23 is inserted from the upper surface of the oil pan mounting seat 20 and screwed into a female screw provided on the cylinder block mounting upper plate 19.

FIG. 21 shows an internal combustion engine in which a cylinder is arranged in a V-shape, and a communication drill hole 24 is provided in the cylinder head H in which valve arm lubricating oil inside the valve arm chamber on the upper surface of the cylinder head H is provided.
In order to return to the inside of the cylinder block B such as the camshaft chamber 26 by the communication cutout hole 25 provided in the cylinder block B, in the configuration in which the inclined groove 27 is provided on the upper surface of the cylinder head H, the inclination angle α of the inclined groove 27 is FIG. 22 is a front cross-sectional view showing a configuration in which the cylinder is configured to have an angle larger than half the V bank angle β, and FIG. 22 shows the push rod 14 in the valve arm chamber 28.
23 is a front cross-sectional view showing a conventional technique in which the push rod 14 through hole is used as a return oil passage for the valve arm lubricating oil by being housed inside. FIG. FIG. 4 is a front sectional view of a conventional technique that is configured as follows.

The route of lubricating oil in the internal combustion engine is as follows.
The technique described in Japanese Utility Model Publication No. 46-26643 was known. In the technique shown in FIG. 21, the inclined groove 27 is provided on the upper surface of the cylinder head H, and the inclined groove 2 is formed.
The bottom of 7 has a bottom surface with an inclination angle α. Further, the inclination angle α is configured to be larger than an angle β which is half the V bank angle of the cylinder. With this configuration, even when the lubricating oil stays inside the valve arm chamber 28, it always returns from the camshaft chamber 26 to the inside of the cylinder block B along the inclination angle α of the inclined groove 27. Of. In the case of a V type engine, the V bank angle of the cylinder is inclined to either side, so that the lubricating oil collects on this inclined side. In this case, if there is no inclination angle α, the lubricating oil cannot be guided to the communication drill hole 24 and the communication drill hole 25. According to the present invention, the cylinder head H can be used for both the left and right sides of the V-shape, and can also be used for the cylinder head H of the internal combustion engine of another in-line cylinder.

[0038]

Since the present invention is constructed as described above, it has the following effects. According to the first aspect of the invention, the narrowest gap k between the balance weight and the interfering substance such as the cylinder 3 and the piston 2 at the angle of each crankshaft 4 in one revolution of the crankshaft is made substantially constant. It is possible to secure a larger mass in the same space as compared with the conventional balance weight. Further, it becomes possible to secure the largest mass of the balance weight in the crank space of the limited space, and the outer peripheral shape of the balance weight can be made compact. Further, it is possible to secure a large mass of the balance weight in the limited space of the crank chamber by using the same material.

In the second aspect, the balance weight 1
The shape of the first corner recess 11a contacts a line one step lower than the joint surface between the inner fixed seat 11b of the balance weight 11 and the balance weight mounting seat 5a protruding from the crankshaft, and passes through the end of the mounting surface. By forming an arc having a large radius, the joining surface is one step higher than the tangent line of the arc, which facilitates the processing of the inner fixed seat 11b surface. Further, it is possible to avoid interference between the corner portion 5b of the balance weight mounting seat 5a protruding from the crankshaft and the corner recess 11a. Also, the corner recess 11a
It is also possible to improve the strength against cracking in the area. Thereby, the mass of the balance weight can be maximized in the minimum space. Further, by increasing the mass of the balance weight, the efficiency of canceling the vibration of the internal combustion engine is improved. Further, with respect to the mass of the balance weight thus increased, it is possible to form the corner recess 11a in which cracking does not occur.

According to the third aspect, the push rod 14 is eccentrically arranged on the center side of the cylinder block B, the intake valve arm 12 and the exhaust valve arm 22 are downsized, and the valve arm chamber is reduced. The effect that 28 becomes small occurs. Further, it is not necessary to provide a separate component such as the swing arm 15 and the increase in the number of components is avoided, which contributes to cost reduction. Further, it is not necessary to process the tappet guide 16 of the roller tappet 36 which is inclined with respect to the center line of the cylinder block B, which facilitates the processing.

According to the fourth aspect, the intake valve arm 12 and the exhaust valve arm 22 can be used as the same component in the internal combustion engine. This allows
The number of parts can be reduced, the cost can be reduced, and the mistake in assembling the internal combustion engine can be prevented.

According to the fifth aspect of the invention, the amount of lubricating oil in the oil pan 18 can be increased without increasing the height of the internal combustion engine. Further, since the bolt 23 can be screwed from above, assembly and disassembly is facilitated.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration of the present invention in which both hem portions of a balance weight 1 configured in a semi-arcuate shape are expanded and inflated more than a semicircle.

FIG. 2 is a front view of a state in which the crankshaft 4 rotates slightly to form the narrowest gap k between the shoulder portion 1c of the balance weight 1 and the lower end portions 2b of both ends of the piston 2.

FIG. 3 is a front view of a state in which the crankshaft 4 is further rotated and a narrowest gap k is formed at a position just before the protruding inflating portion 1a.

FIG. 4 is a front view showing a state in which the narrowest gap k is formed in the projecting expansion section 1a.

FIG. 5 is a front view of a conventional balance weight 1 ′, which is configured in a semicircular arc shape along a circumference.

FIG. 6 is a front view of a conventional balance weight 1'rotated to a position where a shoulder portion 1c and lower end portions 2b of both ends constitute a narrowest gap k.

FIG. 7 is a balance weight mounting projecting from the crank shaft at an inner fixed seat 11b of the balance weight 11 for fixing the balance weight 11 fixedly mounted on the crank shaft of the internal combustion engine to the balance weight mounting seat 5a projecting from the crank shaft. FIG. 6 is a front view showing a shape in which a corner recess 11a for avoiding interference with a corner of the seat 5a is cut into an arc shape constituted by an arc having a large radius.

FIG. 8 is a front view showing a state in which an inner fixed seat 11b of the balance weight 11 is fixed to a balance weight mounting seat 5a of the crankshaft 4.

FIG. 9 is a front view showing a state where the balance weight 11 is processed by the machine tool M.

FIG. 10 is an enlarged view of a shape in which the corner concave portion 11a is cut into an arc shape formed by an arc having a large radius.

FIG. 11 is an enlarged view of a configuration in which the corner recess 11a is cut into a shape having two small radii.

FIG. 12 shows a structure in which the cam shaft 8 is arranged at a position lower than the supply / exhaust valve 13, and the valve arm 12 and the cam shaft 8 arranged above are connected by a push rod 14 on the cam shaft 8. FIG. 3 is a front cross-sectional view showing a configuration in which a roller tappet 10 that contacts the cam 9 is eccentric from the center of the cam shaft 8 and the roller tappet 10 reciprocates on a center line that is parallel to the center of the cylinder 3.

FIG. 13 is a front cross-sectional view showing a configuration in which the center of the camshaft 8 and the center of the roller tappet 10 are aligned with each other, which is a conventional technique.

FIG. 14 is a view showing another conventional configuration, in which a swing arm 15 is interposed in order to eccentrically center the cam shaft 8 and the center of the roller tappet 10 and to fill a gap therebetween. Front sectional view.

FIG. 15 is a view showing another conventional technique, in which the roller tappet 10 and the balance weight 11 are arranged toward the center of the camshaft 8 and the roller tappet 36 is fitted on the tappet guide 16 which is obliquely arranged. The front expanded sectional view shown.

FIG. 16 is a view in which the supply / exhaust valve is arranged in parallel with the direction of the camshaft, the cam position on the camshaft is arranged in the vicinity of the supply cam / exhaust cam / fuel cam, and the valve arm shaft 17 is used as the camshaft. FIG. 3 is a plan view of a portion of the intake valve arm 12 and the exhaust valve arm 22 showing a configuration in which the intake valve arm 12 and the exhaust valve arm 22 are arranged in parallel and can be used in common.

FIG. 17 shows an intake valve arm 12 and an exhaust valve arm 22 showing a conventional technique.
Plan view of the portion of FIG.

FIG. 18 is a plan view of an intake valve arm 12 and an exhaust valve arm 22 showing another conventional technique.

FIG. 19 is a bottom view of the cylinder block B at the mounting portion of the cylinder block B and the oil pan 18, where an oil pan mounting seat 2 protruding from the outer surface of the cylinder block B is provided.
0 is provided, the cylinder block mounting upper plate 19 is also provided on the upper surface of the oil pan 18, and the bolt 23 is inserted from the upper surface of the oil pan mounting seat 20 on the cylinder block B side,
FIG. 3 is a front sectional view showing a configuration in which a cylinder block mounting upper plate 19 on the oil pan 18 side is screwed.

FIG. 20: Conventional oil pan 18 and cylinder block B
And FIG.

FIG. 21 is a diagram showing an internal combustion engine in which cylinders are arranged in a V-shape; the valve arm lubricating oil inside the valve arm chamber on the upper surface of the cylinder head H is communicated with the communication drill hole 24 provided in the cylinder head H; In the configuration in which the inclined groove 27 is provided on the upper surface of the cylinder head H in order to return to the inside of the cylinder block B such as the camshaft chamber 26 by the drill hole 25,
FIG. 6 is a front sectional view showing a configuration in which an inclination angle α of the inclined groove 27 is larger than an angle β which is half the V bank angle of the cylinder.

FIG. 22 is a front sectional view showing a conventional technique in which the push rod 14 is housed in the valve arm chamber 28 so that the push rod 14 through hole serves as a return oil passage for the valve arm lubricating oil.

23 is a front cross-sectional view of a conventional technique in which a valve arm lubricating oil collecting groove 30 having no inclination is formed on the upper surface of a cylinder head H. FIG.

[Explanation of symbols]

 B Cylinder block H Cylinder head α Inclination angle β Half of V bank angle of cylinder 1,11 Balance weight 1a Projection expansion part 2 Piston 3 Cylinder 4 Crankshaft 5 Crankshaft arm outer circumference 8 Camshaft 9 Cam 12 Air supply valve arm 13 Supply / Exhaust Valve 14 Push Rod 18 Oil Pan 26 Cam Shaft Chamber 28 Valve Arm Chamber 36 Roller Tappet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F16F 15/26 8917-3J F16F 15/26 B 15/34 8917-3J 15/32 G

Claims (5)

[Claims] 1. A balance weight fixedly mounted on a crankshaft of an internal combustion engine, wherein the piston and the balance weight are in contact with each other while the balance weight is approaching within about ± 90 degrees before and after top dead center even when the crankshaft rotates. Between the cylinder liner and the balance weight so that the minimum clearance between them is constant, the outer shape of the semicircular arc portion of the balance weight is such that both hem portions are expanded outside the circular arc. organ. 2. An inner fixed seat of a balance weight for fixing a balance weight fixedly mounted on a crank shaft of an internal combustion engine to a balance weight mounting seat projecting from the crank shaft, to prevent interference with a corner portion of the crank shaft mounting seat. An internal combustion engine, wherein the corner recesses to be avoided are formed by scooping out an arc shape formed by an arc having a large radius. 3. The camshaft is arranged at a position lower than the supply / exhaust valve, and the valve arm and the camshaft arranged above are connected to each other by a push rod so as to contact the cam on the camshaft. An internal combustion engine characterized in that a roller tappet is eccentric from a center of a camshaft, and the roller tappet is reciprocated on a center line parallel to a cylinder center. 4. In a structure in which a camshaft is arranged at a position lower than a supply / exhaust valve and a valve arm and a camshaft arranged above are connected by a push rod, An internal combustion engine characterized in that an air cam, an exhaust cam, and a fuel cam are arranged in this order, and a valve arm shaft is arranged in parallel with the cam shaft so that both the intake valve arm and the exhaust valve arm can be used. 5. An oil pan mounting seat projecting from an outer surface of the cylinder block is provided at a lower portion of the cylinder block in a mounting portion of the cylinder block and the oil pan of the internal combustion engine, and the cylinder block is also provided on an upper surface of the oil pan. An internal combustion engine characterized in that a mounting upper plate is provided, a bolt is inserted from the upper surface of an oil pan mounting seat on the cylinder block side, and the bolt is inserted into the cylinder block mounting upper plate on the oil pan side.