JP2724738B2 - Balancer shaft drive for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Industrial Application Field The present invention relates to a first case in which a balancer shaft having an eccentric weight portion is rotatably supported by an engine body and attached to the engine body. A gear chamber is formed between the member and a second case member attached to the first case member, and a driven gear fixed to one end of the balancer shaft is rotatable with the second case member in parallel with the balancer shaft. A drive gear provided at an inner end of the supported rotating shaft and meshing with the driven gear is housed in the gear chamber, and an outer end of the rotating shaft protruding from the second case member is cranked through a winding transmission system. The present invention relates to a balancer shaft driving device for an internal combustion engine that is linked to and connected to a shaft.

(2) Conventional Technology Conventionally, a driven gear fixed to a balancer shaft and a drive gear provided on a rotary shaft interlocked with and connected to a crankshaft mesh with each other in a gear chamber to drive the balancer shaft. Such an apparatus is known, for example, from Japanese Utility Model Application Laid-Open No. 56-60842.

(3) Problems to be Solved by the Invention In such a device, lubricating oil is supplied to the rotating shaft support of the second case member, and the lubricating oil flows into the gear chamber from the support. When the lubricating oil is filled in the gear chamber, the driving gear and the driven gear that mesh with each other operate while stirring the lubricating oil,
Power increases due to stirring resistance. For this reason, in the above-mentioned prior art, the above problem is solved by disposing a lubricating oil discharge hole communicating with a lower portion in the gear chamber. However, since the gear chamber is closed, if the lubricating oil is discharged from the lubricating oil discharge hole, the pressure in the gear chamber is reduced, and it is difficult to discharge the lubricating oil smoothly.

The present invention has been made in view of such circumstances,
An internal combustion engine that smoothly discharges lubricating oil from the gear chamber to prevent an increase in power due to agitation of the lubricating oil in the gear chamber, and that further reduces the size of the first case member and simplifies the structure of the engine body. It is an object of the present invention to provide a balancer shaft driving device.

B. Configuration of the Invention (1) Means for Solving the Problems According to a first aspect of the present invention, there is provided a balancer shaft having an eccentric weight portion rotatably supported by an engine body. A gear chamber is formed between a first case member attached to a side wall of the engine body and a second case member attached to the first case member, and a balancer shaft is inserted into the side wall of the engine body. Are provided so as to communicate with the inside of the engine body, and the first holes corresponding to the insertion holes are provided.
The case member is provided with a bearing hole that supports an end of the balancer shaft protruding from the insertion hole, and a driven gear fixed to one end of the balancer shaft protruding into the gear chamber through the bearing hole; A drive gear, which is provided at an inner end of a rotation shaft rotatably supported by the second case member and is meshed with the driven gear, is housed in the gear chamber, and the rotation shaft protrudes from the second case member. A balancer shaft driving device for an internal combustion engine having an outer end interlocked and connected to a crankshaft via a winding transmission system, wherein a first case member has a lubricating oil discharge that communicates a lower portion in a gear chamber into the engine body. A hole and an air introduction hole which is open above the lubricating oil discharge hole and has one end opened in the gear chamber and the other end directly connected to the insertion hole, and the air introduction hole is provided for the drive gear and the driven gear. No. 1 near the meshing part It is formed on the scan element.

According to the second aspect of the present invention, an oil seal is provided between an outer end of the second case member and the rotating shaft, and an oil passage having one end communicating with an inner part of the oil seal is provided. The other end of the oil passage formed in the second case member is opened at a lower portion in the gear chamber so as to face the lubricating oil discharge hole.

(2) Operation According to the configuration of the first feature, the lubricating oil that has flowed into the gear chamber is lubricated while avoiding a state where the gear chamber is depressurized by introducing air from the upper air introduction hole. It is discharged smoothly from the oil discharge hole. Moreover, since the air introduction hole is disposed near the meshing portion of the drive gear and the driven gear, where an empty space is relatively likely to be formed in the first case member, the air introduction hole does not affect the outer shape of the first case member, and thus is sufficiently provided. A large diameter air introduction hole can be easily provided in the first case member. Further, since the air introduction hole is provided in the first case member so as to directly communicate with the insertion hole for inserting the balancer shaft on the side wall of the engine main body, it is not necessary to provide a special hole in the engine main body. Becomes

According to the second feature of the present invention, in particular, the lubricating oil that has flowed out from the bearing surface between the second case member and the rotating shaft toward the oil seal is formed by the oil passage of the case member, the lower portion in the gear chamber, and the lubricating oil. It is discharged smoothly through the discharge hole.

(3) Embodiment Hereinafter, an embodiment in which the present invention is applied to a balancer shaft driving device of a DOHC type in-line four-cylinder internal combustion engine will be described with reference to the drawings. First, FIGS. 1, 2, 3 and 4
In the figure, an engine body E is configured by connecting a cylinder head 2 to an upper portion of a cylinder block 1, an oil pan 3 is connected to a lower portion of the cylinder block 1, and a head cover 4 is connected to an upper portion of the cylinder head 2. You.

The cylinder block 1 has an upper cylinder barrel portion 1a.
And a lower half crankcase portion 1b made of an aluminum alloy. The cylinder barrel portion 1a is provided with four cylinder bores 5 arranged in series, and a piston 6 is slidably fitted in each of the cylinder bores 5. A plurality of journal bearings 7 are spaced from each other along the direction in which the cylinder bores 5 are arranged in the crankcase portion 1b, and a bearing cap 8 fixed to the lower surface of each journal bearing 7 is provided. A crank shaft 9 is rotatably supported by the journal bearings 7. The crank pins 9 a of the crank shaft 9 are connected to the pistons 6 via connecting rods 10. The bearing caps 8 are integrally connected by a bridge member 11.

At one axial end of the crankshaft 9, the cylinder block 1
An oil pump 12 driven by the crankshaft 9 is disposed on the outer surface 1c of the side wall of the vehicle. The oil pump 12 includes a pump case 13 as a first case member attached to the side wall outer surface 1c of the cylinder block 1 and a rotor 14 fixed to the crankshaft 9 housed therein. An oil strainer 17 is connected to the suction port 15 provided through a suction pipe 16. Also pump case 13
Is connected to a lubricating oil passage 19 formed in the cylinder block 1 in parallel with the crankshaft 9. The other axial end of the crankshaft 9 slightly projects from the other end side wall of the cylinder block 1, and a transmission is connected to the other end of the crankshaft 9 via a clutch (not shown).

5 and 6, the crankshaft 9
A first balancer shaft 21 and a second balancer shaft 22 are arranged at positions substantially symmetrical with respect to a vertical plane passing through the axis of the crankshaft 9 so as to be rotatable in parallel with the crankshaft 9. These balancer shafts 21 and 22 are for suppressing secondary vibration of the engine, and are inserted through the cylinder block 1 while projecting one axial end from the side wall outer surface 1c of the cylinder block 1. Thus, both balancer shafts 21 and 22 are eccentric weight portions 21a and 21 spaced apart from each other near their other ends in the axial direction.
b; 22a, 22b, the cylinder block 1 is provided with a pair of bearing holes 23, 24 for supporting a portion near the other end in the axial direction of the first balancer shaft 21; A pair of bearing holes that support the portion near the other end in the axial direction
Bearing holes 27 are provided for supporting portions of the second balancer shaft 22 near one end in the axial direction.

One end of the crankshaft 9 is a pump case of the oil pump 12
The first drive pulley 28 of the first winding transmission system T1 is fixed to the protruding end of the crankshaft 9 and is closer to the cylinder block 1 than to the first drive pulley 28. The second drive pulley 29 of the second winding transmission system T2 is fixed to the side going away, and both drive pulleys 28, 29 are driven to rotate in the directions indicated by arrows in FIG.

The first winding transmission system T1 includes an intake-side valve operating cam mechanism 30 that is rotatably supported by the cylinder head 2 in parallel with the crankshaft 9 to drive the intake-side valve operating mechanism, and an exhaust-side valve operating mechanism. An exhaust valve camshaft 31 that is rotatably supported by the cylinder head 2 in parallel with the crankshaft 9 to be driven, and a water pump that is mounted on the outer surface 1c of the side wall of the cylinder block 1
32, a first drive pulley 28, driven pulleys 33 and 34 for driving camshafts respectively fixed to both camshafts 30 and 31, and a pump shaft 3 of the water pump 32.
A driven pulley 35 for driving a water pump fixed to 2a,
And a first timing belt 36 suspended around each pulley 28, 33, 34, 35.

The second winding transmission system T2 includes first and second balancer shafts 21 and 2
2 is a transmission system for driving the second drive pulley 29.
The driven pulley 37 is connected to the first balancer shaft 21 and linked to the reverse drive, and the driven pulley 38 is provided to the second balancer shaft 22 for normal rotation. And an endless second timing belt 39.

8 and 9, a gear case 42 as a second case member that covers a part of the pump case 13 is attached to the pump case 13 at a portion corresponding to the first balancer shaft 21. Pump case 13 and gear case 42
A gear chamber 94 is formed therebetween. That is, the gear case 42
Is attached to the cylinder block 1 together with the pump case 13 by bolts 43. The reverse pulley driven pulley 37
Is fixed to a protruding end of the rotating shaft 44, which is rotatably supported by the gear case 42 in parallel with the first balancer shaft 21, from the gear case 42. Moreover, one end of the first balancer shaft 21 protrudes into the gear chamber 94 while being rotatably supported by the pump case 13. That is, the outer surface 1c of the side wall of the cylinder block 1
The first balancer shaft 21 is mounted on the pump case 13
A bearing hole 13a is provided for rotatably supporting one end of the first balancer shaft 21. The protruding end of the first balancer shaft 21 projects into the gear chamber 94 between the pump case 13 and the gear case 42 from the bearing hole 13a. . Thus, in the gear chamber 94, the driven gear 41 fixed to the end of the first balancer shaft 21 and the drive gear 40 provided integrally with the inner end of the rotary shaft 44 are meshed with each other. Therefore, power from the reverse rotation driven driven pulley 37 is transmitted to the first balancer shaft 21 via the gears 40 and 41 that mesh with each other. That is, both balancer shafts 21 and 22 are rotationally driven in mutually opposite directions.

Referring also to FIG. 9, a support shaft 45 parallel to the crankshaft 9 is implanted in the cylinder block 1 above the crankshaft 9. The support shaft 45 is provided with a large-diameter screw portion 45 on the proximal end side.
a and a shaft portion 45b having a male screw 45c smaller in diameter than the large-diameter screw portion 45a on the distal end side are coaxially connected via a flange portion 45d, and the flange portion 45d is brought into contact with the side wall outer surface 1c. The large-diameter threaded portion 45a is screwed into the cylinder block 1 so as to be in contact with the cylinder block 1.

The support shaft 45 has a first tensioner for adjusting the tension of the first timing belt 36 in the first winding transmission system T1.
46 is supported, and a second tensioner 47 for adjusting the tension of the second timing belt 39 in the second winding transmission system T2 is supported on an axially outer side of the first tensioner 46.

10 and 11, the first tensioner 46 is
A plurality of balls 50 are interposed between an inner ring 48 supported by a shaft portion 45b of the support shaft 45 and an outer ring 49 sliding on the outer surface of the first timing belt 36. The ring-shaped support member 51, which is press-fitted and fixed to the outer surface, has a pair of protrusions.
51a and 51b project outward on one diameter line. A shaft hole 52 is formed in one of the protrusions 51a.
The first tensioner 46 is swingably supported by a shaft 53 that penetrates through and is fixed to the cylinder block 1. Thus the inner ring
An arc-shaped long hole 54 centering on the shaft 53 is formed in the hole 48, and the shaft portion 45 b of the support shaft 45 is inserted into the long hole 54. In addition, the other end of the first tension spring 55 whose one end is engaged with the cylinder block 1 is engaged with the other protrusion 51b,
The outer ring 49 of the first tensioner 46 is pressed against the first timing belt 36 from the outside thereof by the spring force of the first tension spring 55, whereby a constant tension is applied to the first timing belt 36.

The second tensioner 47 includes a plurality of balls 57 interposed between an inner ring 56 and an outer ring 58 slidably contacting the second timing belt 39. One end of a tensioner arm 59 pivotally supported by a shaft 60 fixed to the cylinder block 1 in parallel with the crankshaft 9 is fixed to the inner ring 56.
Moreover, an arc-shaped long hole 61 centering on the shaft 60 is formed in the center of the inner ring 56, and the shaft portion of the support shaft 45 is formed in the long hole 61.
45b is inserted. Further, a second tension spring 62 is stretched between the other end of the tension arm 59 and the cylinder block 1, and the outer ring 58 is attached to the second timing belt 39 from the outside by the spring force of the second tension spring 62. The second contact belt 39 is pressed, whereby a constant tension is applied to the second timing belt 39. In the second tensioner 47, the width of the outer ring 58 is set smaller than the width of the outer ring 49 in the first tensioner 46.

Thus, the first timing belt 36 in the first winding transmission system T1 is pressed inward from the outside by the first tensioner 46 on the loose side between the first drive pulley 28 and the driven pulley 35 for driving the water pump. As a result, the gear case 42 is deeply curved inward, and the gear case 42 is disposed in an empty space generated by the curved surface. Moreover, the first tensioner 46
The angle α formed by the pressing direction of the first timing belt 36 by the first tension belt 47 and the pressing direction of the second timing belt 39 by the second tensioner 47 is 90 degrees or more, preferably 120 degrees or more.
Set to 30 degrees.

The first winding transmission system T1 and the second winding transmission system T2 are covered by a side cover 65, and the tip of the support shaft 45 penetrates through the side cover 65 and protrudes outward. In addition, the nut 66 that is screwed into the male screw 45c at the tip of the support shaft 45 and abuts the inner ring end surface of the second tensioner 47 is a side cover.
The nut 66 is rotatably engaged with the nut 65 so that the nut 66 can be rotated from outside the side cover 65. Thus, the first and second tensioners 46, 47 are tightened by tightening the nut 66.
Inner rings 48 and 56 are in contact with each other so as to be relatively movable in a plane orthogonal to the axis of the support shaft 45.

A rotating wheel 67 protruding outward from the side cover 65 is fixed to the crankshaft 9, and a third driving pulley 68 of a third winding transmission system T <b> 3 is attached to the rotating wheel 67 on the inner side in the axial direction. And the fourth drive pulley 69 of the fourth winding transmission system T4 is integrally provided on the outer side in the axial direction.

The third winding transmission system T3 is a transmission system for driving the AC generator 70 and the air conditioner compressor 71 attached to the cylinder block 1, and includes a third drive pulley 68.
And a driven pulley 72 for driving the AC generator fixed to the input shaft of the AC generator 70, a driven pulley 73 for driving the compressor fixed to the input shaft of the compressor 71 for the air conditioner, and each pulley 68, 72, 73. Endless endless belt 74
It is composed of The fourth winding transmission system T4 is a transmission system for driving a power steering hydraulic pump 75 mounted on the cylinder head 2, and includes a fourth drive pulley 69.
And a driven pulley 76 for driving the hydraulic pump, which is fixed to the input shaft of the hydraulic pump 75, and an endless belt 77 suspended by the two pulleys 69, 76.

Next, the structure of the lubricating oil supply system will be described. The lubricating oil supplied from the oil pump 12 to the lubricating oil passage 19 provided in the cylinder block 1 is provided between the two inner cylinder bores 5 along the arrangement direction. The portion corresponding to the located journal bearing 7 is guided to an oil filter 80 attached to the side surface of the cylinder block 1. Moreover, cylinder flock 1
An oil passage 81 for guiding the lubricating oil from the oil filter 80 to the valve operating mechanism above and an oil passage 82 for guiding the lubricating oil downward are formed.

On the other hand, a bridge member 11 for interconnecting the bearing caps 8 is provided with a central oil passage 83 corresponding to the crankshaft 9 and side portions corresponding to the balancer shafts 21 and 22 on both sides of the central oil passage 83, respectively. Oil passages 84 and 85 are formed in parallel with the crankshaft 9. The bridge member 11 includes the oil passages 83, 84, 85
Are connected to each other at a longitudinally intermediate portion of the oil passages 83 to 85 so as to be orthogonal to the oil passages 83 to 85.

Each of the bridge member 11 and each of the bearing caps 8 is provided with an oil supply passage 87 extending upward with a lower end communicating with a central oil passage 83 so as to supply lubricating oil to a support portion of the crankshaft 9. In the portions corresponding to the bearing holes 23 and 24 of the balancer shaft 21, the lower end of the bridge member 11, the bearing cap 8 and the cylinder block 1 is communicated with the side oil passage 84, and the upper end is connected to the bearing holes 23 and 24, respectively. Lubrication channels 88, 88 to communicate
And a bridge member 11, a bearing cap 8 and a cylinder block 1 at one axial end of the crankshaft 9.
An oil supply passage 89 having a lower end communicating with the side oil passage 84 is formed so as to extend vertically, and the oil supply passage 89 is connected to an oil supply passage 90 formed in the pump case 13. This oil supply passage 90 communicates with the balancer shaft 21 support portion of the pump case 13,
It also communicates with a rotating shaft 44 support in the gear case 42. In a portion corresponding to the bearing holes 25, 26, 27 of the balancer shaft 22, the bridge member 11, the bearing cap 8, and the cylinder block 1 have:
The lower end communicates with the side oil passage 85 and the upper end
Oil supply passages 91 communicating with 5, 26, and 27 are respectively formed.

Oil passage 82 for guiding lubricating oil from oil filter 80 downward
Is communicated with the intermediate portion of the oil supply passage 88 at a portion corresponding to the bearing hole 24.Therefore, the lubricating oil from the oil filter 80 is supplied to the oil passages 83, 84, 85 of the bridge member 11 through the oil supply passage 88.
Will be supplied.

Referring again to FIGS. 7 and 8, the second winding transmission system
The rotating shaft 44 to which the driven pulley 37 for reverse rotation drive of T2 is fixed,
The gear case 42 is rotatably supported via the cylindrical bearing metal 95. Lubricating oil is supplied from the oil supply passage 90 between the bearing metal 95 and the rotating shaft 44, and prevents the lubricating oil flowing out between the rotating shaft 44 and the bearing metal 95 from leaking from the axial outer end of the gear case 42. For bearing metal
The gear case 42 and the rotary shaft 44
An oil seal 96 is interposed therebetween.

The gear case 42 has one end communicating with the inside of the oil seal 96 and the other end opening at the lower part in the gear chamber 94.
An opening end of the oil passage 97 is opposed to a lubricating oil discharge hole 98 described later. Therefore, the lubricating oil flowing out from between the bearing metal 95 and the rotating shaft 44 to the oil seal 96 side is smoothly returned to the lower part in the gear chamber 94 through the oil passage 97, and further to the lubricating oil discharge hole 98 described later. It has become.

In addition, some lubricating oil directly flows into the gear chamber 94 from between the bearing metal 95 and the rotary shaft 44, and lubricating oil also flows into the gear chamber 94 from the portion where the first balancer shaft 21 is supported by the pump case 13. I do. In order to discharge the lubricating oil flowing into the gear chamber 94 in this manner, a lubricating oil discharge hole 98 communicating with a lower portion in the gear chamber 94 is formed in the pump case 13, and the lubricating oil discharge hole is also formed in the cylinder block 1. A lubricating oil discharge hole 99 is formed to connect the hole 98 to the inside of the cylinder block 1.

Further, the pump case 13 has a portion above the lubricating oil discharge hole 98 near the meshing portion of the two gears 40 and 41, for example, both the gears 40 and 41.
At a portion (see FIG. 2) corresponding to the engagement start position of 41, an air introduction hole 100 communicating with the gear chamber 94 is formed, and the air discharge hole 100 communicates with the cylinder block 1. That is, the first balancer shaft 21 is inserted into the side wall of the cylinder block 1 where the pump case 13 is to be mounted.
A communication hole 101 is formed coaxially with 3, 24, and the insertion hole 1 is formed.
01 is communicated with the air introduction hole 100.

Next, the operation of this embodiment will be described. The rotation of the crankshaft 9 drives the first to fourth winding transmission systems T1 to T4. As a result, in the first winding transmission system T1, the valve train camshafts 30, 31 are driven with a 1/2 reduction ratio with respect to the crankshaft 9, and the water pump 32 is driven. In the second winding transmission system T2, both balancer shafts 21, 22 are driven in opposite directions with a speed increase ratio of 2/1 with respect to the crankshaft 9.

Thus, a first tensioner 46 for adjusting the tension of the first timing belt 36 in the first winding transmission system T1,
Since the second tensioner 47 for adjusting the tension of the second timing belt 39 in the winding transmission system T2 is supported by the common support shaft 45, the arrangement of the tensioner can be made compact. Moreover, in the first winding transmission system T1, the valve operating camshafts 30 and 31 and the water pump 3
2 is driven, a larger driving load is applied than the second winding transmission system T2, but the first tensioner 46 is connected to the second tensioner.
Since the support shaft 45 is provided on the inner side in the axial direction than the support shaft 47, the load applied to the distal end side of the support shaft 45 can be minimized.

By setting the angle α between the pressing directions of the first and second tensioners 46 and 47 to 90 degrees or more, preferably 120 degrees or more, the load direction applied to the support shaft 45 can be shifted to reduce the overall load. , The first and second
In combination with the arrangement of the tensioners 46 and 47, the load on the support shaft 45 can be further reduced.

Further, since the load of the second winding transmission system T2 is smaller than the load of the first winding transmission system T1, the outer ring of the second tensioner 47 is
It is possible to make the width of 58 smaller than the width of the outer ring 49 of the first winding transmission system T1, thereby reducing the projecting amount of the support shaft 45 from the cylinder block 1 and contributing to the compactness of the entire engine. can do.

In addition, the lubricating oil flows into the gear chamber 94 in which the gears 40 and 41 meshed with each other to drive the first balancer shaft 21 in the reverse direction, but air flows into the gear chamber 94 from the upper air introduction hole 100. Since the lubricating oil is discharged from the lubricating oil discharge holes 98 and 99 below, the lubricating oil is discharged from the gear chamber 94.
The lubricating oil can be smoothly discharged from the gear chamber 94 without being hindered by the internal pressure reduction. Therefore, the agitation resistance of the lubricating oil by the two gears 40 and 41 can be kept extremely small, and the power for driving the first balancer shaft 21 can be kept small.

By the way, an empty space is formed in the pump case 13 near the meshing portion of the driving gear 40 and the driven gear 41, and the air introduction hole 100 is arranged in this empty space. Therefore, the pump case 1
Since the size 3 is not increased, and the air introduction hole 100 communicates with the insertion hole 101 of the cylinder block 1, it is not necessary to provide a special hole in the cylinder block 1.

C. Effects of the Invention As described above, according to the first aspect of the present invention, the first case member has a lubricating oil discharge hole for communicating a lower portion in the gear chamber with the engine body, and a lubricating oil discharge hole. Since an air introduction hole for communicating the inside of the gear chamber with the engine body is formed at the upper part, the lubricating oil is smoothly discharged from the gear chamber, the stirring resistance is reduced, and the power consumption can be reduced.

Moreover, since the air introduction hole is provided in the vicinity of the meshing portion of the driving gear and the driven gear, where an empty space is relatively likely to be generated in the first case member, the first case member itself can be sufficiently enlarged without particularly increasing the size. First large-diameter air inlet
It can be easily provided on the case member. Further, since the air introduction hole is provided in the first case member so as to directly communicate with the insertion hole for inserting the balancer shaft in the engine body side wall,
It is not necessary to provide a hole that communicates with the air introduction hole in the engine body, and the structure of the engine body can be simplified accordingly.

According to the second feature of the present invention, an oil passage having one end communicating with an inner portion of an oil seal provided between an outer end of the second case member and the rotating shaft is formed in the second case member. ,
The other end of the oil passage is opened at the lower part in the gear chamber so as to face the lubricating oil discharge hole, so that the lubricating oil flowing out from the bearing surface between the second case member and the rotating shaft to the oil seal side is removed from the oil passage. Thus, the oil can be smoothly discharged through the lower portion in the gear chamber and the lubricating oil discharge hole, so that oil leakage at the oil seal portion can be effectively prevented.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a longitudinal side view, FIG. 2 is a view taken along the line II-II of FIG. 1, and FIG.
FIG. 4 is a sectional view taken along the line III-III of FIG.
FIG. 5 is a sectional view taken along line VV of FIG. 3, FIG. 6 is a sectional view taken along line VI-VI of FIG. 3, and FIG. 7 is a sectional view taken along line VII of FIG.
8 is an enlarged sectional view taken along the line VIII-VIII in FIG. 3, FIG. 9 is a sectional view taken along the line IX-IX in FIG. 2, FIG. 10 is a plan view of the first tensioner, FIG. 11 is a sectional view taken along line XI-XI of FIG. 9: crankshaft, 13: pump case as first case member, 13a: bearing hole, 21: balancer shaft, 21a, 21b: eccentric weight, 40: drive gear, 41: driven gear, 42: second case Gear case as a member, 44 ... rotating shaft, 94 ... gear chamber, 98 ...
Lubricating oil discharge hole, 100: air introduction hole, 101: insertion hole, E: engine body, T2: winding transmission system

Continuation of the front page (56) References Practical application Microfilm (JP, U) Principal application Sho56: Photograph of the contents of the specification and drawings attached to the application of Japanese Patent Application No. 54-144398 (Japanese Utility Model Application No. 56-60841) Microfilm (JP, U) photographing the contents of the specification and drawings attached to the application form No. 98789 (Japanese Utility Model Application No. 58-4840)

Claims (2)

(57) [Claims] A first case member (13) rotatably supported on an engine body (E) having an eccentric weight portion (21a, 21b) and mounted on a side wall of the engine body (E). )
And a second case member (42) attached to the first case member (13), a gear chamber (94) is formed, and a balancer shaft (21) is inserted into the side wall of the engine body (E). The first case member (13) corresponding to the insertion hole (101) is provided from the insertion hole (101) so as to communicate with the inside of the engine body (E). A bearing hole (13a) for supporting an end of the projecting balancer shaft (21) is provided, and is fixed to one end of the balancer shaft (21) projecting into the gear chamber (94) through the bearing hole (13a). The driven gear (41) is provided at the inner end of a rotating shaft (44) rotatably supported by the second case member (42) in parallel with the balancer shaft (21) and meshes with the driven gear (41). Drive gear (4
0) is accommodated in the gear chamber (94), and the outer end of the rotating shaft (44) protruding from the second case member (42) interlocks with the crankshaft (9) via the winding transmission system (T2). And a balancer shaft driving device for an internal combustion engine, wherein the first case member (13) has a lubricating oil discharge hole (41) for communicating a lower portion in the gear chamber (94) with the engine body (E). 98) and an air introduction hole (100) having one end opened in the gear chamber (94) above the lubricating oil discharge hole (98) and the other end directly communicating with the insertion hole (101). The air introduction hole (100) is formed in the first case member (13) in the vicinity of the meshing portion of the driving gear (40) and the driven gear (41), and the balancer shaft driving of the internal combustion engine is performed. apparatus. 2. An oil seal (96) is provided between the outer end of the second case member (42) and the rotating shaft (44), and one end communicates with the inner part of the oil seal (96). An oil passage (97) is formed in the second case member (42), and the other end of the oil passage (97) in the gear chamber (94) is opposed to the lubricating oil discharge hole (98). The balancer shaft driving device for an internal combustion engine according to claim 1, wherein the device is opened at a lower portion of the shaft.