JPH03160118A - Crankshaft supporting structure of engine - Google Patents

Abstract

PURPOSE:To facilitate assembly by supporting the end of a crankshaft on a side opposite to a flange molded side by a ball bearing and forming an outer- facing flange as a separate unit for the crankshaft, in the case of supporting structure of the crankshaft on one end of which the outer-facing lange is provided. CONSTITUTION:A crankcase 2 is formed of upper and lower cases 66, 67, vertically divided with the axial center of a crankshaft 3 bordering, while provided with right and left outer walls 61, 62 and a pair of right and left intermediate walls 63, 64, when the crankshaft 3 is rotatably supported to the crankcase 2, a shaft end in an opposite side to the right side shaft end of a main shaft 69 of the crankshaft 3 is supported to the left side outer wall 61 by a ball bearing 74 possible to support-receive thrust force. While the right side shaft end of the main shaft 69 is supported to the right side outer wall 62 by a needle bearing 75 possible to resist a heavy load in a radial direction. Further each main shaft 69, positioned between respective crank arms 72, is supported to the intermediate walls 63, 64 by needle bearings 76. An outer-facing flange 83 as a separate unit is fixed to the right side shaft end of the main shaft 69.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention relates to a horizontal crankshaft support structure for an engine. (Prior Art) The crankshaft of an engine is normally supported at both ends by bearings relative to the crankcase, but since a thrust force acts on the crankshaft, one of the two bearings receives this thrust force. It is necessary to make it possible. For this reason, conventionally, one of the two bearings is a needle bearing, and the other is a ball bearing that receives the above thrust force. Additionally, in this case, the needle bearing or ball bearing is fitted onto the outside of the crankshaft to support the crankshaft. On the other hand, an outward flange for screwing the flywheel is usually attached to one end of the crankshaft of an automobile engine. (Problems to be Solved by the Invention) However, due to the structure of the ball bearing, it is difficult to make the inner race and the outer race into half shapes. For this reason, if an outward flange is formed at each end of the crankshaft as described above, this outward flange will become an obstacle, making it difficult to fit the ball bearing externally onto the end of the crankshaft. There's a problem. Therefore, it may be possible to support the shaft end of the crankshaft on the opposite side from where the outward flange is formed using a ball bearing. However, in this case, when the crankshaft receives a thrust force from the outward flange side, this thrust force is applied over almost the entire crankshaft from the outward flange side to the ball bearing. Therefore, this is not desirable in terms of the strength of the crankshaft. (Object of the Invention) This invention was made in view of the above-mentioned circumstances, and therefore, one of the two bearings for supporting the crankshaft at both ends is a ball bearing, and one end of the crankshaft is When an outward flange is formed on the flange, the ball bearing can be easily aligned outwardly with respect to the shaft end of the crankshaft, and even if the crankshaft receives thrust force from the outward flange side, this thrust force The purpose is to prevent load from being applied to the entire shaft. (Structure of the Invention) The feature of this invention for achieving the above object is that the crankshaft is supported at both ends with respect to the crankcase by needle bearings and ball bearings, and each end of the crankshaft is directed outward. In the engine crankshaft support structure with a molded flange, the shaft end of the crankshaft on the side where the outward flange is molded is supported by a ball bearing, and the outward flange is formed separately from the crankshaft. ．． (Function) The effect of the above configuration is as follows, when the crankshaft 3 is supported at both ends with respect to the crankcase 2 by the ball bearing 74 and the double bearing 75, and -rQ of the same crankshaft 3 is supported at both ends. In the case where the outward flange 83 is molded at the end, one of the ball bearings 74 and the needle bearings 75
4 supports the shaft end of the crankshaft 3 on which an outward flange 83 is formed. In this case, the outward flange 83 is formed separately from the crankshaft 3 and press-fitted into each shaft end of the crankshaft 3. Therefore, when attempting to attach the ball bearing 74 to the shaft end of the crankshaft 3, the ball bearing 74 is first fitted and attached to the shaft end of the crankshaft 3, and then the ball bearing 74 is attached to the end of the crankshaft 3. Outward flange 83
Just press-fit and install. Moreover, the above-mentioned pole bearing 74 has an outward flange 83.
Since the shaft end of the crankshaft 3 on the side is supported, even if the crankshaft 3 receives a thrust force from the outward flange 83 side, this thrust force is applied to the above-mentioned pole bearing 74 located on the outward flange 83 side. This will be supported by (Example) Hereinafter, an example of the present invention will be explained with reference to the drawings. In Figures 2 and 3, 1 in the figure is a two-stroke diesel engine for automobiles. Reference numeral 2 denotes a crankcase, and a crankshaft 3 is housed in a crank chamber 2a within this crankcase 2, and this crankshaft 3 is rotatably supported by the crankcase 2. Further, a cylinder block 4 is installed on the crankcase 2, and this cylinder block 4
A shilling head 5 is attached to the top. The cylinder block 4 is composed of three cylinders 7, and these cylinders 7 are arranged in parallel in the axial direction of the crankshaft 3. Further, a piston 8 is fitted into each of the cylinders 7 so as to be vertically slidable, and the piston 8 is connected to the crankshaft 3 by a connecting piece 9.6 In the cylinder 7, the cylinder head 5 and the piston 8 The space between the two is a combustion chamber l1, and a sub-combustion chamber l2 connected to this combustion chamber l1 is formed in the cylinder head 5. A globe lug 13 and a fuel injection valve l4 face the auxiliary combustion chamber 12. The crankcase 2 is formed with an air intake hole l7 corresponding to each cylinder 7, and each air intake hole l7 is provided with a reed valve l8 that only allows air to flow from the outside to the inside of the crankcase 2. It is provided. This reed valve
8 is composed of a valve body 20 having a valve hole 19, and an elastic thin plate-like valve body 21 that opens and closes the valve hole 19. An intake air manifold 23 connected to each of the air intake holes L7 is attached to the crankcase 2, and the upstream side of this intake air manifold 23 is connected to an air cleaner 25 via a single wooden cylindrical air intake pipe 24. R). A plurality of holes 27 are formed in the cylinder block 4, one end of which opens into the crankcase 2, and the other end of which opens into the combustion chamber 11. The other end is opened and closed by raising and lowering the piston 8. In the cylinder block 4, an exhaust hole 28 is formed for each cylinder 7, and each exhaust hole 28 is opened and closed as the piston 8 moves up and down. Further, an exhaust manifold 29 connected to each of the exhaust holes 28 is attached to the sill block 4, and this exhaust manifold 29 is connected to each of the exhaust holes 28.
A single exhaust pipe 30 is connected to the downstream side of the exhaust pipe 30. And when engine I is operating, piston 8 is up! Then, air is sucked into the crankcase 2 through the air cleaner 25, the air intake pipe 24, the intake air manifold 23, the closed valve 18, and the air intake hole 17 in this order. Then, this air is primarily compressed in the crank chamber 2a as the piston 8 descends, and then the scavenging hole 27
is sent into the combustion chamber l1. Next, the air sent into the combustion chamber I1 is compressed by the rise of the piston 8. Then, fuel is injected Q1 by the fuel injection valve 14 into the air which has become hot due to this compression, and an explosion occurs. 1} in the crank chamber 2a due to the lowering of the piston 8.
As noted in 1j, the primary compressed air flows through the scavenging hole 27.
When it is sent into the combustion chamber 1l through the
The combustion gas in the scavenging hole 27 has its own pressure and
and the air sent into the combustion chamber II through the exhaust hole 28, the exhaust manifold 29, and the exhaust pipe 30, that is, scavenging is performed.

Thereafter, the above steps are repeated, and the power of the engine 1 is outputted via the crankshaft 3. In the above configuration, when the engine 1 is operated, air is drawn into the crank chamber 2a through the air intake pipe 24 as described above, and an adjustment device 34 is provided to adjust the amount of intake air. This adjustment device 34 reduces the amount of intake air when the engine 1 is under low load, and prevents the amount of intake air from becoming excessive with respect to the amount of fuel injected from the fuel injection valve l4. do. The adjustment device 34 includes an on-off valve 36 for adjusting the opening degree of the air intake passage 4l, and a stepping motor 37 as an actuator for opening and closing the on-off valve 36. Further, the on-off valve 36 has a cylindrical valve body 38 interposed in the middle of the air intake pipe 24. This valve body 38 has the same diameter as the air intake pipe 24,
It is connected to each air suction pipe 24 by a joint tube 40, and the inside thereof communicates with the inside of the air suction pipe 24, forming an air suction passage 41. A valve shaft 42 that crosses the air intake passage 41 is rotatably supported on the valve body 38, and a butterfly type valve body 43 is attached to the valve shaft 42. One end of the valve shaft 42 is connected to the valve body 38
A housing 44 protruding from the valve shaft 42 and covering one end of the valve shaft 42 is removably screwed to the valve body 38, and the stepping motor 37 is housed within the housing 44. A large gear 49 attached to one end of the valve shaft 42 meshes with a small gear 48 attached to the stepping motor 37, which means that the power of the stepping motor 37 is decelerated and transmitted to the valve shaft 42. It looks like this. In addition, an integral cover 50 that covers the small gear 48 and the large gear 49 is removably screwed to the housing 44. In FIG. 3, 53 to 55 all indicate sensors, of which 53 54 is a sensor for detecting the rotation speed of the engine l; 54 is a sensor for detecting the amount of fuel injected by the fuel injection valve 14; and 55 is a sensor for detecting the temperature of cooling water for cooling the cylinder block 4 and cylinder head 5. be. An electronic control means 56 is provided to operate the stepping motor 37 by inputting the output signals of the sensors 53 to 55. When it is determined that the engine 1 is under low load based on the outputs of the sensors 53 to 55. T! The single-child control means 56 operates the stepping motor 37, thereby rotating the valve body 43 in a direction to close the air intake passage 41. That is, this reduces the amount of intake air passing through the air intake passage 41, and prevents the amount of intake air from becoming excessive during this low load period. The support structure of the crankshaft 3 relative to the crankcase 2 will be explained with reference to FIGS. 1 and 3. The crankcase 2 has a left side outer wall 61 located on its left side (as viewed in the direction of FIG. 1, hereinafter referred to as the same).
It has a right side outer wall 62 and a pair of left and right intermediate walls 63 and 64. The crankcase 2 is horizontally composed of an upper case 66 and a lower case 67, which are divided into upper and lower parts with the axis of the crankshaft 3 as a border.
67 are screwed together. Further, along with this division, each of the walls 6l to 64 is also divided into upper and lower parts. On the other hand, the crankshaft 3 includes a main shaft 69, three crank bins 7l connected to the large ends 70 of the respective connecting rods 9, and crank arms 72 interposed between the main shaft 69 and the crank bins 7l, respectively. It consists of two parts, which are integrally molded. The right shaft end of the main shaft 69 is a ball bearing 7 that can receive thrust force.
4 is supported on the right side outer wall 62, while the same main shaft 69
The left shaft end of the shaft is supported on the left II+ outer wall 61 by a needle bearing 75 that can withstand particularly heavy loads in the radial direction. Further, each main shaft 69 located between each crank arm 72 is connected to the needle bearing 75, respectively.
It is supported on the intermediate wall 63, 64 by other needle bearings 76, 76 with the same specifications as the one. In the above case, each of the needle bearings 75 and 76 has a half-shape that can be divided into upper and lower parts.
It is said that the diameter is smaller than the part where it is externally fitted, and here there is a booley 78 that drives the auxiliary equipment of engine 1 and the camshaft.
．． 79 and spacer 80 are removably fixed with bolts 8l. On the other hand, an outward flange 83 is formed at each right end of the crankshaft 3, and a flywheel 84 is detachably screwed to this outward flange 83 with bolts 85. Note that the flywheel 84 is connected to a power transmission device via a clutch. In the above case, the outward flange 83 is formed separately from the right end of the crankshaft 3, and the outward flange 83 is fixed to each end of the right end of the crankshaft 3 by press fitting. Therefore, when assembling the ball bearing 74 to the right end of the crankshaft 3, first fit the ball bearing 74 onto the right end of the crankshaft 3 before press-fitting the outward flange 83 onto the crankshaft 3. Then, the outward flange 83 may be press-fitted. On the other hand, the needle bearing 7 for the crankshaft 3
5. When attempting to release the external fitting of 76, first loosen the screws that fasten the upper case 66 and lower case 67 to each other, and then move them both up and down relative to the crankshaft 3. Pull apart. Then, the radially outer sides of the needle bearings 75 and 76 are opened. Here, as mentioned above, each needle bearing 75.76
are each split in half, so although they are sandwiched from the left and right by the crank arm 72 and the outward flange 83, they can be easily removed from the main shaft 69 without being obstructed by these. Furthermore, when attempting to fit the needle bearings 75, 76 onto the crankshaft 3, the procedure may be reversed to that described above. In FIGS. 3 and 4, the large end 70 shown in iii is composed of a main body 87 and a cap 89 screwed to the main body 87 with a bolt 88. A crank bottle 7L is sandwiched between the rotary motor 7E. Furthermore, working holes 90 are formed on the lower surface of the crankcase 2 to correspond to the respective caps 89, and the bolts 88 can be screwed or loosened through the working holes 90, and This working hole 9
0 so that the cap 89 can be inserted and removed through it. Then, by removing the cap 89 in this way, the crankcase 2 can be moved between the upper case 66 and the lower case 67.
toward the top of each cylinder 7 without dividing into
Main body portion 87 of the large end portion 70 of the piston 8 or connecting rod 9
can be extracted in one piece. In addition, a cover integrated 92 that closes the working hole 90 can be freely opened and closed.
will be established. This cover unit 92 is detachably attached to the lower surface of the crankcase 2 with bolts 93. In the above case, the work hole 90 shown by the temporary line in FIG. 3 and the center left and right in FIG.
This shows the state with 2 removed. Although the above is based on the illustrated example, the engine 1 may be a gasoline engine, and may be a 4-cycle engine.

(Effects of the Invention) According to the present invention, the crankshaft of the engine is supported at both ends with respect to the crankcase by a twenty-one dollar bear tongue and a ball bearing, and an outward flange is formed at each end of the same crankshaft. In the structure, the shaft end of the crankshaft in which the outward flange described in 42 is molded is supported by a ball bearing, and since the above outward flange is formed separately from the crankshaft, the ball bearing is supported at the shaft end of the crankshaft. When trying to install the
2. Install the ball bearing on the shaft end of the crankshaft with the ball bearing facing outward, and then install the outward flange on the end of the crankshaft. That is, since the outward flange is separate from the crankshaft, the ball bearing can be attached to the crankshaft without any problem, regardless of the provision of the outward flange.

In addition, since the above-mentioned pole bearing supports the shaft end of the crankshaft on the outward flange side, even if the crankshaft receives thrust force from the outward flange side, this thrust force will be located on the outward flange side. It is supported by the ball bearings mentioned above. Therefore, the thrust force is prevented from being applied to the entire crankshaft, which is beneficial for the strength of the crankshaft. (Margin below)

[Brief explanation of the drawing]

The figures show an embodiment of the invention, and Figure 1 is 1-1 in Figure 3.
2 is an overall plan view, FIG. 3 is a side sectional view, and FIG. 4 is a view taken along the line IV--IV in FIG. 1. l...Engine, 2...Crankcase, 3...Crankshaft, 74...Ball bearing, 75 Needle bearing, 83...Outward flan.

Claims (1)

[Claims] 1. In an engine crankshaft support structure in which the crankshaft is supported at both ends relative to the crankcase by needle bearings and ball bearings, and an outward flange is formed at each end of the above crankshaft, the above outward flange is formed. An engine crankshaft support structure in which the end of the side crankshaft is supported by a ball bearing, and the outward flange is formed separately from the crankshaft.