JP2014173450A - Crank bearing structure of engine - Google Patents

Abstract

A crank hitting sound generated when a main journal hits a journal bearing portion is reduced.
An oil reservoir chamber 11 is formed in a journal bearing portion 2R that pivotally supports a main journal 4a of a crankshaft 4 via a main metal 3R, and an inlet of an oil inflow passage 11a communicating with the oil reservoir chamber 11 is formed. And the outlet of the oil outflow passage 11b are opened to the downstream side and the upstream side across the portion of the bearing surface 2a where the main journal 4a strikes. Lubricating oil staying in the oil reservoir 11 is supplied to the oil groove 3a of the main metal 3R according to the rotation of the main journal 4a, and the vibration when the main journal 4a strikes the main metal 3R by the supplied lubricating oil. Rank energy is reduced by converting energy into kinetic energy and thermal energy.
[Selection] Figure 4

Description

  The present invention relates to a crank bearing structure for an engine in which a crank hitting sound generated when a journal portion provided on a crankshaft is pressed against a bearing metal is reduced.

  As is well known, an engine mounted on a vehicle such as an automobile widely uses a cylinder block cast from an aluminum alloy in order to reduce the weight. The cylinder block is provided with a plurality of journal bearings, and each journal bearing supports a crankshaft rotatably via a bearing metal. This crankshaft is often formed using an iron-based material.

  When the engine is operating, both the journal bearing and the crankshaft are thermally expanded by heat generated by combustion of the air-fuel mixture in the cylinder. At that time, the bearing metal mounted on the bearing surface of the journal bearing part due to the difference in thermal expansion coefficient between the journal bearing part formed integrally with the cylinder block made of aluminum alloy and the journal part made of iron-based material. And the outer circumference of the journal portion (bearing gap) increases. Since the crankshaft converts the reciprocating motion of the piston into a rotational motion, during the combustion stroke, the journal portion is momentarily pressed (impacted) against the surface of the bearing metal due to the combustion pressure acting on the piston. A sound (so-called crank hitting sound) is generated.

  Since this crank hitting sound causes noise and vibration when the vehicle travels, various measures have been conventionally taken. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-1099), the bearing clearance is always properly maintained by casting a plurality of iron-based materials having a low thermal expansion coefficient at predetermined intervals into the journal bearing portion. Techniques that can be used are disclosed.

JP 2004-1099 A

  However, the technique disclosed in the above-described document has a problem that the manufacturing process becomes complicated because an iron-based material having a low thermal expansion coefficient needs to be cast one by one when casting the cylinder block.

  In addition, when machining the bearing surface of the journal bearing portion, the pre-cast iron-based material is also machined at the same time, but each iron-based material is thin and easily deformed elastically during processing. There is a problem that the number of processing steps of the bearing surface increases.

  In view of the above circumstances, an object of the present invention is to provide a crank bearing structure for an engine that is easy to manufacture and post-process and can reduce cranking noise.

  The present invention is attached to a crankshaft that converts a reciprocating motion of a piston into a rotational motion, a journal bearing portion that is provided on a cylinder block side and supports a journal portion of the crankshaft, and a bearing surface of the journal bearing portion. In the crank bearing structure of an engine provided with a bearing metal, an oil reservoir chamber for retaining lubricating oil is formed in the journal bearing portion, and an oil inflow passage and an oil outflow communicating the oil reservoir chamber with the bearing surface A passage is formed, and the inlet of the oil inflow passage and the outlet of the oil outflow passage are opened to the downstream side and the upstream side across the portion of the bearing surface where the journal portion hits. It is characterized by being.

  According to the present invention, an oil reservoir chamber is formed in the journal bearing portion, and the downstream of the portion where the journal portion collides between the inlet of the oil inlet passage communicating with the oil reservoir chamber and the outlet of the oil outlet passage. Since the structure is merely opened on the side and the upstream side, casting work and post-processing are not required, and manufacturing and post-processing are facilitated. Further, when the journal portion rotates, the lubricating oil discharged from the outlet of the oil outflow passage to the bearing surface passes through a portion where the journal portion strikes, and a part of the lubricating oil is discharged from the inlet of the oil inflow passage to the oil reservoir chamber. In this case, the vibration energy generated when the journal part hits the bearing surface of the journal bearing through the bearing metal is converted into kinetic energy and heat energy by this lubricating oil. The hitting sound can be reduced.

Sectional drawing which looked at schematic structure of the engine by a 1st embodiment from the back Sectional plan view of the journal bearing that supports the main journal of the crankshaft Same perspective view of main metal Same as above, IV-IV sectional view of FIG. The same shows the pressure sensing valve, (a) is a sectional view when the valve is closed, (b) is a sectional view when the valve is opened. The thermo valve is shown, (a) is a sectional view when the valve is closed, (b) is a sectional view when the valve is opened Sectional drawing equivalent to FIG. 4 by 2nd Embodiment

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
1 to 6 show a first embodiment of the present invention. Reference numeral 1 in FIG. 1 is a cylinder block, and a cylinder block of a horizontally opposed engine is illustrated in the drawing.

  The cylinder block 1 is made of an aluminum alloy and is divided from the center into left and right bank blocks 1L and 1R. The bank blocks 1L and 1R are integrally formed with a plurality of left and right journal bearing portions 2L and 2R each having a semicircular bearing surface 2a at the center. A pair of main metals (bearing metals) 3L and 3R are mounted on the bearing surfaces 2a of the left and right journal bearing portions 2L and 2R, respectively.

  The main journal 4a as the journal portion of the crankshaft 4 is the main metal 3L as the bearing metal on the bearing surface 2a of the pair of left and right journal bearing portions 2L and 2R that are circular when the left and right bank blocks 1L and 1R are joined. , 3R. The crankshaft 4 is made of an iron-based material, and as shown in FIG. 2, a crankpin 4c is integrally formed with the main journal 4a via a crank arm 4b. Further, a piston 6 is connected to the crank pin 4c via a connecting rod 5, and the piston 6 is inserted into a cylinder bore 7 formed in the left and right bank blocks 1L and 1R so as to be reciprocally movable. The main journal 4a supports both sides of the crank pin 4c. Therefore, in the case of a four-cylinder engine, the main journal 4a is formed at five positions with the crank pin 4c interposed therebetween.

  Further, as shown in FIG. 3, each main metal 3L, 3R is formed with an oil groove 3a at the center in the width direction of the inner peripheral surface, and oil holes 3b are formed in the oil groove 3a at predetermined intervals. ing. The oil hole 3b is formed at a position corresponding to an inlet of an oil inflow passage 11a and an outlet of an oil outflow passage 11b opened in bearing surfaces 2a of left and right journal bearing portions 2L and 2R described later. ing. In the assembled state, the oil holes 3b, the inflow port of the oil inflow passage 11a, and the outflow port of the oil outflow passage 11b are disposed at substantially the same position, and thus the reference numerals attached to the inflow port and the outflow port are omitted. .

  Although not shown, the main journal 4a has an oil passage penetrating in the radial direction. Lubricating oil pressurized by an oil pump (not shown) is supplied to the oil passage and ejected in the axial radial direction. The

  As shown in FIG. 2, an oil reservoir chamber 11 for retaining lubricating oil is formed in a pair of left and right journal bearing portions 2L and 2R that pivotally support each main journal 4a. An oil inflow passage 11a and an oil outflow passage 11b communicating with the bearing surface 2a are formed. FIG. 4 shows the journal bearing portion 2R of the right bank block 1R. The oil reservoir chamber 11 formed in the left journal bearing portion 2L, and the oil inflow passage 11a and the oil outflow passage 11b are point-symmetric with respect to the right journal bearing portion 2R and the dividing surfaces of the left and right bank blocks 1L and 1R. Since the structure is the same and the structure is the same, the drawings are omitted. Further, the crankshaft 4 shown in the present embodiment rotates in the clockwise direction as viewed in the drawing of FIG. 4, and therefore, the lubricating oil flows between the main journal 4 a and the main metals 3 </ b> L and 3 </ b> R. It flows along the clockwise direction that is the direction of rotation.

  When the piston 6 into which the cylinder bore 7 of the left bank block 1L is inserted is in the combustion stroke, and the piston 6 is pushed down by the combustion pressure, the main journal 4a presses (impacts) the right journal bearing portion 2R with a high pressing force Fc. ) The inlet of the oil inflow passage 11a and the outlet of the oil outflow passage 11b are located between the downstream side and the upstream side across a portion where the main journal 4a strikes the main metal 3R mounted on the right journal bearing portion 2R. Opened in the bearing surface 2a.

  A pressure check valve 12 is interposed in the oil inflow passage 11a, and a thermo valve 13 is interposed in the oil outflow passage 11b. FIG. 5 illustrates the pressure check valve 12 and FIG. 6 illustrates the thermo valve 13.

  This pressure check valve 12 opens when the pressure of the lubricating oil flowing into the oil inflow passage 11a from the oil groove 3a of the main metal 3L, 3R through the oil hole 3b becomes a predetermined value or more, as shown in FIG. As shown, the check ball 12a and a spring 12c that presses the check ball 12a against the upstream valve seat 12b. When the lubricating oil pressure is low, the check ball 12a is pressed against the valve seat 12b by the urging force of the spring 12c to close the valve, as shown in FIG. When hydraulic pressure is generated in the passage 11a, the spring 12c is moved backward by the pressing force as shown in FIG.

  The thermo valve 13 is opened when the temperature of the lubricating oil staying in the oil reservoir 11 is not less than a predetermined temperature (for example, 120 ° C.), and is formed in a disk shape as shown in FIG. The bimetal 13a has a valve body 13b fixed at the center of the bimetal 13a, and the outer periphery of the bimetal 13a is supported by the annular groove 13c. When the temperature of the lubricating oil staying in the oil reservoir 11 is lower than a set temperature (for example, 120 ° C.), the bimetal 13a has the valve body 13b on the downstream side of the oil outflow passage 11b as shown in FIG. It sits on the formed valve seat 13d and closes it. On the other hand, when the temperature of the lubricating oil staying in the oil reservoir 11 becomes higher than the set temperature, the bimetal 13a is reversed and the valve body 13b is opened as shown in FIG. 6 (b).

  Next, the operation of the present embodiment having such a configuration will be described. When the engine is stopped and the oil pump is stopped, no hydraulic pressure is generated between the main journal 4a and the oil groove 3a formed in the main metal 3L, 3R. Therefore, the left and right journal bearings 2L, 2R As shown in FIG. 5A, the pressure check valve 12 interposed in the oil inflow passage 11a communicating with the formed oil sump chamber 11 receives the urging force of the spring 12c as shown in FIG. The valve seat 12b is pressed to close the valve. In addition, when the engine is cold due to the parking for a long time, the lubricating oil staying in the oil reservoir 11 is also cold, so that the bimetal 13a of the thermo valve 13 causes the valve body 13b to move as shown in FIG. The valve seat 13d is pressed to close the valve.

  Thereafter, when the engine is started and hydraulic pressure is generated in the oil groove 3a of the main metal 3L, 3R by the lubricating oil discharged from the oil pump, the hydraulic pressure flows into the oil inflow passage 11a through the oil hole 3b. Then, as shown in FIG. 5 (b), the spring 12c of the pressure check valve 12 interposed in the oil inflow passage 11a is pressed and retracted, and the check ball 12a is opened to enter the oil reservoir chamber 11. Lubricating oil flows in and the oil reservoir 11 is filled with lubricating oil.

  On the other hand, when the engine is operated, a large combustion pressure acts on the piston 6 in the combustion stroke, and this combustion pressure is transmitted to the crankshaft 4 via the connecting rod 5 so that the crankshaft 4 rotates. At that time, for example, when the piston 6 inserted through the cylinder bore 7 of the left bank block 1L is in the combustion stroke, the main journal 4a of the crankshaft 4 is formed in the right bank block 1R as shown in FIG. The main metal 3R mounted on the journal bearing portion 2R is pressed (impacted) with a strong pressing force Fc.

  Then, vibration energy due to the impact is propagated to the lubricating oil flowing between the main journal 4a and the main metal 3R, and this vibration energy is converted into the kinetic energy and heat energy of the lubricating oil. The temperature of the lubricating oil staying in the oil reservoir 11 is raised.

  When the temperature of the lubricating oil staying in the oil reservoir 11 exceeds a predetermined temperature (for example, 120 ° C.), as shown in FIG. 6B, a thermo valve 13 interposed in the oil outflow passage 11b. The bimetal 13a is inverted to open the valve body 13b. Then, the lubricating oil staying in the oil reservoir 11 is discharged from the outlet of the oil outflow passage 11b, and the discharged lubricating oil is rotated by the main journal 4a from the oil groove 3a formed in the main metal 3R. Along the portion where the pressing force Fc acts (impacts) (the position indicated by the arrow in FIG. 4) and flows toward the oil inflow passage 11a.

  A part of the oil flows into the oil reservoir chamber 11 from the inlet of the oil inflow passage 11a and is circulated. Therefore, when the engine is continuously operated, the main journal 4a hits the main metal 3R intermittently, and the vibration energy is converted into the kinetic energy and heat energy of the lubricating oil each time. As a result, the crank sound generated by the impact is reduced and the oil temperature of the lubricating oil staying in the oil reservoir 11 is raised.

  As described above, in the present embodiment, the oil inflow passage 11a is formed on the downstream side of the bearing surface 2a of the journal bearing portion 2R, with the portion receiving the impact from the main journal 4a, and the oil outflow passage 11b on the upstream side. Since it is formed, the lubricating oil retained in the oil reservoir 11 can be constantly supplied to the portion that receives the impact of the journal bearing portion 2R. As a result, the lubricating oil converts the vibration energy generated by the impact into kinetic energy and thermal energy, so that the crank hitting sound can be reduced. Further, since heat energy is generated by the impact, the lubricating oil at the time of start-up can be quickly heated, and fuel consumption can be improved by promoting warming up of the lubricating oil.

  Even if the bearing clearance becomes larger due to the difference in the thermal expansion coefficient between the cylinder block 1 and the crankshaft 4, and the crank behavior becomes larger accordingly, it is struck by the lubricating oil supplied from the oil reservoir 11 to the bearing clearance. Since the energy at the time of the collision is converted into kinetic energy and heat energy, the crank hitting sound can be greatly reduced even when shifting to a high load operation after the completion of warm-up.

  Thereafter, when the engine is stopped, the rotation of the crankshaft 4 stops, and the hydraulic pressure of the lubricating oil flowing through the oil groove 3a of the main metal 3R gradually decreases, so the pressure check valve 12 interposed in the oil inflow passage 11a. Is closed and the lubricating oil is held in the oil reservoir 11. Therefore, at the time of hot restart, the lubricating oil staying in the oil reservoir 11 can be quickly supplied to the oil groove 3a of the main metal 3R.

  In the present embodiment, the behavior of the right bank block 1R on the journal bearing portion 2R side has been mainly described. However, it is formed in the left bank block 1L when the piston 6 of the right bank block 1R is in the combustion stroke. The behavior when the main journal 4a collides with the journal bearing portion 2L is applicable by replacing the right journal bearing portion 2R described above with the left journal bearing portion 2L, and thus the description thereof is omitted.

  Thus, according to the present embodiment, the oil reservoir chamber 11 is formed in the journal bearing portions 2L and 2R that pivotally support the main journal 4a of the crankshaft 4, and the oil inflow passage 11a that communicates with the oil reservoir chamber 11 is formed. And the outlet of the oil outflow passage 11b are opened to the downstream side and the upstream side across the portion where the main journal 4a strikes, and stays in the oil reservoir 11 at the portion where the impact occurs. Since the lubricating oil is positively supplied, vibration energy due to the impact can be converted into kinetic energy and heat energy by the supplied lubricating oil. As a result, it is possible to reduce the crank hitting sound generated by the impact, to promote the warm-up of the lubricating oil, and to improve the fuel efficiency.

  Further, the oil reservoir chamber 11, the oil inflow passage 11a, and the oil outflow passage 11b formed in the journal bearing portions 2L and 2R are simple in structure, do not require casting work, and facilitate post-processing, thereby reducing manufacturing costs. Can be achieved.

[Second Embodiment]
FIG. 7 shows a second embodiment of the present invention. In addition, about the component same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In this embodiment, the inlet of the oil inflow passage 11a is opened to the side facing the rotation direction of the main journal 4a, and the outlet of the oil outflow passage 11b is opened in a direction along the rotation direction of the main journal 4a. is there.

  Thereby, more lubricating oil can be made to flow in into the oil reservoir chamber 11 from the oil inflow passage 11a, and more lubricating oil can be discharged from the oil outflow passage 11b. A large amount of lubricating oil can be efficiently supplied from the reservoir chamber 11 to the oil groove 3a of the main metal 3R (3L), crank noise can be reduced efficiently, and early warm-up of the lubricating oil is promoted. be able to.

  The present invention is not limited to the above-described embodiments. For example, the engine to be applied is not limited to the horizontally opposed engine, but may be an inline engine or a V engine. In this case, the oil reservoir 11 is formed in a journal bearing portion (for example, a bearing cap) on the side facing the piston across the main journal.

1 ... Cylinder block,
1L ... Left bank block,
1R ... Right bank block,
2L ... left journal bearing,
2R ... right journal bearing,
2a ... bearing surface,
3L, 3R ... main metal,
4 ... crankshaft,
4a ... main journal,
6 ... Piston,
11 ... Oil reservoir,
11a ... oil inflow path,
11b ... Oil spill path,
12 ... Pressure check valve,
13 ... Thermo valve,
Fc ... Pressing force

Claims (5)

A crankshaft that converts the reciprocating motion of the piston into a rotational motion; a journal bearing portion that is provided on the cylinder block side and supports the journal portion of the crankshaft; and a bearing metal that is mounted on the bearing surface of the journal bearing portion; In the crank bearing structure of the engine comprising
An oil reservoir chamber for retaining lubricating oil is formed in the journal bearing portion, and an oil inflow passage and an oil outflow passage for communicating the oil reservoir chamber and the bearing surface are formed,
An engine characterized in that an inlet of the oil inflow passage and an outlet of the oil outflow passage are opened on the downstream side and the upstream side across the portion of the bearing surface where the journal portion hits. Crank bearing structure. 2. The crank bearing structure for an engine according to claim 1, wherein a pressure check valve that opens upon receiving the pressure of the lubricating oil from the bearing surface side is interposed in the oil inflow passage. The engine crank according to claim 1 or 2, wherein a thermo valve that opens when the temperature of the lubricating oil retained in the oil reservoir chamber is not less than a predetermined temperature is interposed in the oil outflow passage. Bearing structure. The crank bearing structure for an engine according to any one of claims 1 to 3, wherein the inlet is opened toward the flow of the lubricating oil with respect to the bearing surface. The crankshaft structure for an engine according to any one of claims 1 to 4, wherein the outlet is opened in a direction along the flow of the lubricating oil with respect to the bearing surface.

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