JP5310657B2 - Balancer device for internal combustion engine - Google Patents

Description

  The present invention relates to a balancer device for an internal combustion engine, and more particularly to a balancer device for an internal combustion engine in which a balancer housing that rotatably supports a pair of balance shafts is formed integrally with an engine block.

  In general, in a multi-cylinder internal combustion engine, for example, an imbalance occurs in the rotational balance of the crankshaft due to the secondary inertia force generated by the reciprocating motion of the piston in the vertical direction, and this causes the vertical vibration in the internal combustion engine. Occurs. For this reason, the internal combustion engine is provided with a balancer device that suppresses vibrations of the internal combustion engine.

  In the balancer device, two balance shafts provided with eccentric balance weights are rotatably supported by a balancer housing mounted so as to be located in the oil pan at the lower part of the crankcase, and in the oil pan. The balancer housing is covered so that the stored oil and the oil flowing down from the cylinder block do not come into contact with each other.

  In the balancer device having such a configuration, when the internal combustion engine is started, the balance shaft is rotated at a speed twice the rotation speed of the crankshaft by the rotational driving force of the crankshaft. The secondary inertia force of the internal combustion engine is removed to reduce the vibration of the internal combustion engine.

  In addition, there is a balancer device in which a balancer housing is formed integrally with a crankcase. In this balancer device, the balancer housing is formed integrally with the crankcase via a connecting portion such as a rib (for example, , See Patent Document 1).

  By the way, the oil which lubricated the lubrication part of the internal combustion engine is recirculated from the cylinder block to the oil pan through the crankcase. Since the balancer housing is interposed between the crankcase and the oil pan, in the balancer housing formed integrally with the crankcase, the balancer housing is connected between the connecting portion connecting the balancer housing and the crankcase. The oil dropped from the cylinder block through the crankcase is returned to the oil pan.

  Generally, the amount of oil that lubricates the lubrication part of the internal combustion engine is large, and it is necessary to efficiently recirculate the oil that lubricated the lubrication part to the oil pan. For this reason, in order to return a large amount of oil through the connecting portions, it is necessary to increase the interval between the connecting portions, that is, to increase the oil passage area.

  However, in order to increase the oil passage area, it is necessary to secure the oil passage area by, for example, reducing the width of the connecting portion, so that the rigidity of the connecting portion is reduced and the balancer device is sufficiently attached to the crankcase. There is a possibility that it cannot be supported with sufficient strength.

  In order to prevent the rigidity of the connecting portion from being lowered, the balancer housing has a balance shaft bearing portion that rotatably supports the balance shaft, and a crankcase and an oil pan communicate with the balance shaft bearing portion. Some have return holes (see, for example, Patent Document 2).

  In Patent Document 2, the return hole is formed in the balance shaft bearing portion instead of forming the return hole between the connection portions, thereby preventing the rigidity of the connection portion from being lowered. The oil dripped from the crankcase can be recirculated from the return hole.

JP 2002-250399 A Japanese Utility Model Publication No. 3-59432.

  However, in the balancer device described in Patent Document 2, since the return hole is formed in the balance shaft bearing portion, the oil dropped from the crankcase collides with the balance shaft and then returns from the return hole to the oil pan. Since the oil is recirculated, the agitation resistance of the balance shaft increases, and the oil bounced off from the balance shaft scatters to the peripheral members such as the crankshaft, thereby increasing the agitation resistance of the peripheral members such as the crankshaft. There was a problem of letting it go.

  The present invention has been made to solve the above-described conventional problems, and it is possible to achieve both improvement in rigidity of the connecting portion and improvement in oil circulation performance while reducing agitation resistance of the balance shaft. An object of the present invention is to provide a balancer device for an internal combustion engine.

  In order to achieve the above object, a balancer device for an internal combustion engine according to the present invention is (1) interposed between an engine block and an oil pan, and an outer peripheral portion is connected to the engine block via a connecting portion. The balancer housing formed integrally with the engine block, and a pair of balance shafts that are rotatably provided in the balancer housing and to which the rotational power of the crankshaft is transmitted. A balancer device for an internal combustion engine in which an oil passage for communicating the engine block and the oil pan is formed in a space surrounded by the block and the balancer housing, wherein at least one of the connecting portions includes the engine block And the oil pan is formed with a communication hole that communicates with the oil pan.

  This balancer device for an internal combustion engine has a balancer housing formed integrally with the engine block by connecting the outer peripheral portion to the engine block via the connecting portion, and is surrounded by the connecting portion, the engine block, and the balancer housing. In addition to the formation of an oil passage for communicating the engine block and the oil pan in the space to be communicated, a communication hole for communicating the engine block and the oil pan is formed in at least one of the connecting portions. A hole can be formed in the outer periphery of the balancer housing.

  For this reason, the oil dripped from the engine block does not collide with the balance shaft and is returned to the oil pan, thereby preventing an increase in stirring resistance of peripheral members of the balance shaft such as the balance shaft and the crankshaft. Can do.

  In addition to the oil passage, oil dropped from the engine block can be returned to the oil pan through the communication hole formed in the connecting portion, so that the oil passage area is reduced without reducing the rigidity of the connecting portion. Can be increased.

  As a result, the rigidity of the connecting portion can be improved and the balancer housing can be firmly supported by the cylinder block, the mounting strength of the balancer device can be improved, and the oil circulation performance can be improved.

  In the balancer device for an internal combustion engine according to the above (1), (2) the connecting portion is configured to increase in width from the balancer housing toward the engine block.

  In the balancer device of the internal combustion engine, since the connecting portion is configured to increase in width as it goes from the balancer housing to the engine block, the rigidity of the connecting portion between the engine block and the connecting portion can be increased. The mounting strength can be further improved.

  In the balancer device for an internal combustion engine according to the above (2), (3) the connecting portion is configured to have a lateral width that increases from the balancer housing toward the engine block, and the communication hole includes the communication hole. It is comprised from what is formed in the said connection part so that it may be biased to the engine block side.

  This internal combustion engine balancer device is configured such that the lateral width of the connecting portion increases from the balancer housing toward the engine block, and the communication hole is formed in the connecting portion so as to be biased toward the engine block. A communication hole can be formed at the site of the wide connecting portion. For this reason, the opening area of the communication hole can be increased without reducing the strength of the connecting portion, and both the improvement of the rigidity of the connecting portion and the improvement of the oil circulation performance can be efficiently achieved.

  In the balancer device for an internal combustion engine according to the above (1) to (3), (4) a part of an oil supply pipe for supplying oil to a lubrication site of the internal combustion engine is inserted into at least one of the connecting portions. It is composed of what will be done.

  In this internal combustion engine balancer device, since at least one of the connecting parts is inserted with a part of an oil supply pipe for supplying oil to the lubrication part of the internal combustion engine, the connecting part can be reinforced by the oil supply pipe. And the strength of the connecting portion can be improved.

  In addition, since a part of the oil supply pipe is inserted into the connecting part instead of the oil passage, the oil passage area can be prevented from being reduced by the oil supply pipe, and the oil circulation performance is improved. Can be made.

  (1) The balancer device for an internal combustion engine according to (1) to (4), wherein (5) the crankshaft is provided on a shaft portion and the shaft portion, and is arranged separately in the axial direction of the shaft portion. And a plurality of large-diameter rotating parts having a diameter larger than the diameter of the shaft part, and among the communication holes, the opening area of the communication hole located radially outward of the large-diameter rotating part is formed small. In addition, the communication hole is formed to have a large opening area located radially outward of the shaft portion.

  In this balancer device for an internal combustion engine, the communication hole may be located radially outward of the large-diameter rotating part due to the positional relationship of the communication hole. At this time, when the oil dropped from the engine block is introduced into the communication hole located radially outward of the large-diameter rotating part, the oil that collides with the large-diameter rotating part rotating with a large centrifugal force is scattered. There is a possibility that oil may not be smoothly introduced into the communication hole due to interference with the oil introduced into the communication hole. For this reason, the opening area of the communication hole located radially outward of the large-diameter rotating part is formed small.

  On the other hand, the oil introduced into the communication hole located radially outward of the shaft portion is not interfered with by the oil scattered from the small diameter shaft portion. For this reason, the communication hole is formed by increasing the opening area of the communication hole located radially outward of the shaft portion by the amount corresponding to the reduction in the opening area of the communication hole located radially outward of the large diameter rotating part. It is possible to prevent the amount of oil returned to the oil pan from being reduced, and to secure a sufficient oil passage area in combination with the communication hole and the oil passage.

  ADVANTAGE OF THE INVENTION According to this invention, the balancer apparatus of the internal combustion engine which can aim at the improvement of the rigidity of a connection part and the improvement of the circulation performance of oil can be provided, reducing the stirring resistance of a balance shaft.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the balancer apparatus of the internal combustion engine which concerns on this invention, and is front sectional drawing of an internal combustion engine. It is a figure which shows one Embodiment of the balancer apparatus of the internal combustion engine which concerns on this invention, and is a perspective view of a balance shaft and a crankshaft. 1 is a view showing an embodiment of a balancer device for an internal combustion engine according to the present invention, and is a top view of a balancer housing and a crankcase. 1 is a diagram showing an embodiment of a balancer device for an internal combustion engine according to the present invention, and is a front sectional view of the periphery of the balancer device located in the lower part of the internal combustion engine. It is a figure which shows one Embodiment of the balancer apparatus of the internal combustion engine which concerns on this invention, and is side surface sectional drawing of the balancer apparatus periphery located in the lower part of an internal combustion engine. It is a figure which shows one Embodiment of the balancer apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the arrangement | positioning shape of the supply passage of oil.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a balancer device for an internal combustion engine according to the present invention will be described with reference to the drawings.
FIGS. 1-6 is a figure which shows one Embodiment of the balancer apparatus of the internal combustion engine which concerns on this invention.
First, the configuration will be described.
In FIG. 1, an engine 10 that is an internal combustion engine includes a cylinder block 11, a crankcase 16, an oil pan 17, and a cylinder head 25, and pistons are provided in a plurality of, for example, four cylinders 12 provided in the cylinder block 11. 13 is stored.

  Each piston 13 is connected to a crankpin 15a of a crankshaft 15 shown in FIG. 2 via a connecting rod 14, and oil (engine oil) is stored below a crankcase 16 in which the crankshaft 15 is housed. An oil pan 17 is attached. The crankcase 16 is attached to the lower part of the cylinder block 11.

  As shown in FIG. 2, the crankshaft 15 includes a counterweight 15m corresponding to each of the four crankpins 15a, a crank journal 15j between both ends in the axial direction and between the cylinders 12, and each crank journal is provided. 15j is rotatably supported on the crankcase 16 side.

  That is, the crankshaft 15 is provided with a counterweight 15m having a larger diameter than the crankpin 15a and the crank journal 15j between the crankpin 15a and the crank journal 15j.

  In the present embodiment, the counterweight 15m constitutes a large-diameter rotating part, and the crankpin 15a and the crank journal 15j constitute a shaft part.

  Further, a valve operating mechanism having an intake cam 26 and an exhaust cam 27 is provided at the upper part of the engine 10, and an injector 10a for injecting fuel into the intake passage 10i and an ignition are provided at the upper part of each cylinder 12, for example. A plug 10b is arranged. The plurality of injectors 10a corresponding to the plurality of cylinders 12 are respectively connected to delivery pipes (not shown) that supply fuel to the plurality of cylinders 12, and discharged from the fuel pump in the fuel tank to the delivery pipes. Fuel (for example, gasoline) is supplied through a predetermined fuel passage. A catalyst device 10c is disposed on the exhaust passage 10e.

  On the other hand, as shown in FIGS. 1 to 5, a balancer device 18 is provided between the crankcase 16 and the oil pan 17, and the balancer device 18 is rotationally driven according to the rotation of the crankshaft 15. The balance shafts 19 and 20 and the balancer housing 31 that rotatably stores the balance shafts 19 and 20 are configured.

  As shown in FIGS. 2 and 3, driven gears 19a and 20a are fixed to the balance shafts 19 and 20, respectively. The driven gears 19a and 20a mesh with each other and have the same number of teeth. For this reason, the balance shafts 19 and 20 rotate at the same speed in opposite directions.

  A driven gear 19b is fixed to the balance shaft 19, and the driven gear 19b meshes with a drive gear 15b provided on the crankshaft 15. The number of teeth of the drive gear 15b and the driven gear 19b is set to 2: 1. Yes.

  For this reason, the balance shafts 19 and 20 rotate at twice the number of rotations of the crankshaft 15. As a method for transmitting the rotation of the crankshaft 15 to the balance shafts 19 and 20, a chain drive method, a belt drive method, or the like may be used in addition to the gear drive method.

  The balance shafts 19 and 20 are provided with balance weights 19c, 19d, 20b and 20c, and the balance weights 19c, 19d, 20b and 20c are formed in a semicircular shape with respect to the axis of the balance shafts 19 and 20. The center of gravity is formed in an eccentric state. Therefore, the balancer device 18 can suppress the vertical vibration and the booming noise caused by the secondary inertia force of the engine 10 by rotating the balance shafts 19 and 20 whose center of gravity is eccentric with respect to the rotation center.

  The balance weights 19c, 19d, 20b, and 20c may be formed separately from the balance shafts 19 and 20, and may be fastened to the balance shafts 19 and 20 with bolts or the like so as to be integrally rotatable.

  As shown in FIG. 6, an oil pump 21 is provided in the oil pan 17, and the oil pump 21 sucks oil stored in the oil pan 17 through an oil strainer 21a, and then opens an oil supply passage 22 through the oil strainer 21a. Via the main gallery 23 provided in the cylinder block 11.

  A plurality of oil supply passages 24 are branched from the main gallery 23, and the oil supply passages 24 supply the oil introduced into the main gallery 23 to the crank journal 15 j of the crankshaft 15. Therefore, the crank journal 15j is lubricated by the oil supplied from the oil supply passage 24.

  The oil supplied to the crank journal 15j is supplied between the connecting rod 14 and the crank pin 15a through holes formed in the radial direction and the axial direction of the crankshaft 15.

  The oil supplied to the main gallery 23 is supplied to the intake cam 26 and the exhaust cam 27 accommodated in the cylinder head 25, and the intake cam shaft that rotatably supports the intake cam 26 and the exhaust cam 27, respectively. 28 and a timing chain 30 that connects the exhaust camshaft 29 and the crankshaft 15.

  On the other hand, as shown in FIGS. 4 and 5, the balancer housing 31 includes a lower housing 32 and an upper housing 33, and the lower housing 32 is fastened and fixed to the upper housing 33 by bolts (not shown).

  As shown in FIG. 4, the lower housing 32 and the upper housing 33 are formed with bearing portions 32a, 32b, 33a, 33b, and the balance shafts 19, 20 are rotatable to the bearing portions 32a, 32b, 33a, 33b. It is supported by. Although the balance shaft 19 is not shown in FIG. 4, the balance shaft 19 is rotatably supported by the same bearing portions 32 a, 32 b, 33 a, and 33 b as the balance shaft 20.

  Further, oil passages 31a and 31b are formed in the bearing portions 32a, 32b, 33a and 33b, and the oil passages 31a and 31b are provided with oil through a branch passage 22a (see FIG. 6) branched from the oil supply passage 22. Is to be supplied. For this reason, the contact surfaces of the bearing portions 32a, 32b, 33a, 33b and the balance shafts 19, 29 are lubricated with oil.

  As shown in FIGS. 3 and 5, the upper housing 33 is connected to the crankcase 16 via four ribs 34 to 37 as connecting portions, and the upper housing 33 is formed integrally with the crankcase 16. Has been.

  Specifically, the crankcase 16 and the upper housing 33 are made of aluminum, aluminum alloy, or the like, and are integrally formed by casting or the like. In the present embodiment, the cylinder block 11 and the crankcase 16 constitute an engine block.

  Since the lower housing 32 is fastened and fixed to the upper housing 33, the balancer housing 31 including the lower housing 32 and the upper housing 33 is formed integrally with the crankcase 16.

  An oil pan 17 is fastened and fixed to the opening peripheral edge portion 16a of the crankcase 16 with a bolt or the like, and the cylinder block 11 is attached to the opening inner edge portion 16c of the inner peripheral portion 16b of the crankcase 16. Installed.

  As shown in FIG. 3, the ribs 34 to 37 have a lateral width that increases from the upper housing 33 toward the inner peripheral portion 16 b of the crankcase 16. The width has increased.

  An oil passage 38 is formed in a space surrounded by the ribs 34, 35, the inner peripheral portion 16 b of the crankcase 16 and the outer peripheral portion of the balancer housing 31, and this oil passage 38 connects the crankcase 16 and the oil pan 17 to each other. Communicate.

  An oil passage 39 is formed in a space surrounded by the ribs 36 and 37, the inner peripheral portion 16 b of the crankcase 16 and the outer peripheral portion of the balancer housing 31, and the oil passage 39 is connected to the crankcase 16 and the oil pan 17. And communicate with.

  On the other hand, the ribs 35, 36, 37 are formed with communication holes 35a, 36a, 37a penetrating in the vertical direction of the ribs 35, 36, 37. The communication holes 35a, 36a, 37a are formed of ribs 35, 36, 37a. The crankcase 16 and the oil pan 17 communicate with each other by opening from the upper surface to the lower surface of 37. In FIG. 3, the communication holes 35a, 36a, and 37a are indicated by hatching.

  The communication holes 35a and 37a are provided facing each other across the axial direction of the crankshaft 15, and the opening area of the communication holes 35a and 37a is larger than the opening area of the communication hole 36a.

  Although not shown in the present embodiment, the communication holes 35a and 37a are located radially outward of the counterweight 15m located at one end of the crankshaft 15, and the communication hole 36a The crank pin 15a located at the other end of the shaft 15 is located radially outward.

  The communication holes 35a, 36a, and 37a are formed in the ribs 35, 36, and 37 so as to be biased toward the inner peripheral portion 16b of the crankcase 16, and are located in wide portions of the ribs 35, 36, and 37. ing.

  A part of the oil supply pipe 40 is inserted through the rib 34, and the oil supply passage 22 is defined by the inner peripheral portion of the oil supply pipe 40. Therefore, the rib 34 constitutes a part of a path for routing the oil supply pipe 40 that supplies the oil discharged from the oil pump 21 to the main gallery 23. In FIG. 3, the oil supply pipe 40 is indicated by hatching.

  In the engine 10 including the balancer device 18 having such a configuration, a part of the oil supplied from the oil pump 21 to the oil supply passage 22 of the oil supply pipe 40 is supplied from the main gallery 23 to the oil supply passage 24. The other oil is supplied from the main gallery 23 to the intake cam 26, the exhaust cam 27, the timing chain 30, and the like.

  The oil supplied to the crankshaft 15, the intake cam 26, the exhaust cam 27, the timing chain 30 and the like falls in the cylinder block 11 and the crankcase 16 by its own weight, and then the oil passages 38 and 39 and the communication holes 35a and 36a. , 37a to the oil pan 17.

  In the present embodiment, the outer peripheral portion is connected to the inner peripheral portion 16 b of the crankcase 16 via the ribs 34 to 37, thereby having the balancer housing 31 formed integrally with the crankcase 16. 35, a space surrounded by the outer peripheral portion of the balancer housing 31 and the inner peripheral portion 16b of the crankcase 16 and a space surrounded by the ribs 36, 37, the outer peripheral portion of the balancer housing 31 and the inner peripheral portion 16b of the crankcase 16 respectively. In addition to forming the oil passages 38, 39, communication holes 35a, 36a, 37a for communicating the crankcase 16 and the oil pan 17 are formed in the ribs 35, 36, 37.

  For this reason, the communication holes 35a, 36a, and 37a can be formed in the outer peripheral portion of the balancer housing 31, and the oil dropped from the cylinder block 11 and the crankcase 16 collides with the balance shafts 19 and 20 to the oil pan 17. By preventing reflux, it is possible to prevent the stirring resistance of the balance shafts 19 and 20 from increasing.

  Further, oil colliding with the balance shafts 19 and 20 and rebounding from the balance shafts 19 and 20 does not scatter to the peripheral members of the balance shafts 19 and 20 such as the crankshaft 15, and the stirring resistance of the peripheral members increases. Can be prevented.

  In addition to the oil passages 38 and 39, oil dropped from the cylinder block 11 and the crankcase 16 through the communication holes 35a, 36a and 37a formed in the ribs 35, 36 and 37 can be returned to the oil pan 17. Therefore, the oil passage area can be increased without reducing the rigidity of the ribs 34 to 37.

  As a result, the rigidity of the ribs 34 to 37 can be improved and the balancer housing 31 can be firmly supported by the crankcase 16, the mounting strength of the balancer device 18 can be improved, and the oil circulation performance can be improved. be able to.

  Further, in the present embodiment, the ribs 34 to 37 are configured such that the lateral width increases from the balancer housing 31 toward the inner peripheral portion 16b of the crankcase 16, so that the inner peripheral portion of the crankcase 16 is increased. The rigidity of the connection part of 16b and the ribs 34-37 can be enlarged, and the attachment strength of the balancer apparatus 18 can be improved further.

  In the present embodiment, the communication holes 35a, 36a, 37a are formed in the ribs 35, 36, 37 so as to be biased toward the inner peripheral portion 16b of the crankcase 16, so that the wide ribs 35, 36, The communication holes 35a, 36a, 37a can be formed in the portion 37, the opening area of the communication holes 35a, 36a, 37a can be increased without reducing the strength of the ribs 35, 36, 37, and the ribs It is possible to efficiently achieve the improvement of the rigidity of 34 to 37 and the improvement of the oil circulation performance.

  In the present embodiment, the rib 34 is reinforced by the oil supply pipe 40 because a part of the oil supply pipe 40 that supplies oil to the crankshaft 15 that is the lubrication part of the engine 10 is inserted into the rib 34. And the strength of the ribs 34 can be improved.

  Further, since part of the oil supply pipe 40 is inserted into the rib 34 instead of the oil passages 38 and 39, it is possible to prevent the area of the oil passages 38 and 39 from being reduced by the oil supply pipe 40. It is possible to improve the oil circulation performance.

  Further, in the present embodiment, the opening area of the communication hole 36a located radially outward of the counterweight 15m is formed small, and the opening area of the communication holes 35a and 37a located radially outward of the crank pin 15a. Formed large.

  That is, when the communication hole 36a is positioned radially outward of the counterweight 15m due to the positional relationship of the communication holes 35a, 36a, 37a, the cylinder block is inserted into the communication hole 36a positioned radially outward of the counterweight 15m. 11 and the oil dropped from the crankcase 16 is introduced into the communication hole 36a because the oil that collides with the counterweight 15m rotating with a large centrifugal force and scatters to the oil introduced into the communication hole 36a. Oil may not be introduced smoothly. For this reason, the opening area of the communication hole 36a located radially outward of the counterweight 15m is formed small.

  On the other hand, the oil introduced into the communication holes 35a and 37a located radially outward of the crank pin 15a is not interfered with by the oil scattered from the small diameter crank pin 15a.

  For this reason, the opening area of the communication holes 35a and 37a positioned radially outward of the crank pin 15a is increased by the amount corresponding to the reduction of the opening area of the communication hole 36a positioned radially outward of the counterweight 15m. Therefore, it is possible to prevent a reduction in the amount of oil recirculated to the oil pan 17 through the communication holes 35a, 36a, 37a, and a sufficient amount of oil combined with the communication holes 35a, 36a, 37a and the oil passages 38, 39. A passage area can be secured.

  In the present embodiment, the balancer housing 31 is connected to the inner peripheral portion of the crankcase 16 via the ribs 34 to 37, but the balancer housing 31 is connected to the cylinder block 11 via the ribs 34 to 37. You may do it.

  In the present embodiment, the communication holes 35a, 36a, 37a are formed in the ribs 35, 36, 37. However, the communication holes may be formed in all of the ribs 34-37. Moreover, you may form a communicating hole in at least 1 or more of the ribs 34-37.

  Further, in the present embodiment, the ribs 34 to 37 are formed such that the lateral width increases from the upper housing 33 toward the inner peripheral portion 16b of the crankcase 16, but the inner periphery of the crankcase 16 extends from the upper housing 33. You may make it form the width | variety of the vertical direction of the ribs 34-37 large as it goes to the part 16b.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the balancer device for an internal combustion engine according to the present invention has an effect that it is possible to improve both the rigidity of the connecting portion and the oil circulation performance while reducing the stirring resistance of the balance shaft. Further, it is useful as a balancer device for an internal combustion engine in which a balancer housing that rotatably supports a pair of balance shafts is formed integrally with an engine block.

10 Engine (Internal combustion engine)
11 Cylinder block (engine block)
15 Crankshaft 15a Crankpin (shaft)
15j Crank journal (shaft)
15m counterweight (large diameter rotating part)
16 Crankcase (Engine block)
17 Oil pan 18 Balancer device 19, 20 Balance shaft 31 Balancer housing 34-37 Rib (connecting part)
35a, 36a, 37a Communication hole 38, 39 Oil passage 40 Oil supply pipe

Claims (5)

A balancer housing that is interposed between the engine block and the oil pan and has an outer peripheral portion connected to the engine block via a connecting portion, and a balancer housing that is formed integrally with the engine block, and the balancer housing A pair of balance shafts that are rotatably provided to transmit the rotational power of the crankshaft. The engine block and the oil pan communicate with each other in a space surrounded by the connecting portion, the engine block, and the balancer housing. A balancer device for an internal combustion engine in which an oil passage is formed,
A balancer device for an internal combustion engine, wherein a communication hole for communicating the engine block and the oil pan is formed in at least one of the connecting portions.   2. The balancer device for an internal combustion engine according to claim 1, wherein the connecting portion has a width that increases from the balancer housing toward the engine block. 3.   The connecting portion is configured to have a lateral width that increases from the balancer housing toward the engine block, and the communication hole is formed in the connecting portion so as to be biased toward the engine block side. The balancer device for an internal combustion engine according to claim 2, wherein the balancer device is an internal combustion engine.   4. A part of an oil supply pipe for supplying oil to a lubrication site of the internal combustion engine is inserted into at least one of the connecting parts. 2. A balancer device for an internal combustion engine according to 1. The crankshaft includes a shaft portion, and a plurality of large-diameter rotating portions that are provided on the shaft portion and are spaced apart in the axial direction of the shaft portion and have a diameter larger than the diameter of the shaft portion. ,
Among the communication holes, an opening area of a communication hole located radially outward of the large-diameter rotating part is formed small, and an opening area of a communication hole located radially outward of the shaft part is formed large The balancer device for an internal combustion engine according to any one of claims 1 to 4, wherein the balancer device is configured as described above.

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