JPH02212641A - Balancer shaft driven device for internal combustion engine - Google Patents

Abstract

PURPOSE:To ensure an effective contact width even when unevenness in size precision and axial relative movement between two gears occur by a method wherein a margin width wide enough to allow other tooth width is provided for the one of the tooth widths of a drive gear on the rotary shaft side and a driven gear on the balancer shaft side. CONSTITUTION:A second wrapping transmission system T2 rotationally drives a balancer shaft 21 through a driven pulley 37 for reverse drive, a driven gear 40, and a driven gear 41 by means of a timing belt 39 by rotation of a crank shaft togetherwith a driven pulley. The drive gear 40 is integrally fixed on a rotary shaft 44 togetherwith the driven pulley 37, and engagement therebetween is effected such that a tooth width D1 of the drive gear provides margin widths D2a and D2b for a tooth width D2 of the driven gear 41 secured to the one end of the balancer shaft 21. This constitution enables ensurance of an effective contact width even when unevenness in size precision and axial relative movement between the two gears occur, and permits prevention of the increase of a friction amount of a tooth surface and the generation of noise.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Field of Application The present invention is characterized in that a balance support having an eccentric weight portion is rotatably supported on an engine body, and the balancer is attached to a case member attached to the engine body. A driving gear is provided at one end of a rotating shaft that is rotatably supported parallel to the shaft, a driven gear that meshes with the driving gear is fixed to the balancer shaft, and the other end of the rotating shaft is connected to the rotating shaft via a wrapped transmission system. The present invention relates to a balancer shaft drive device for an internal combustion engine that is interlocked and connected to a crankshaft.

(2) Prior art Conventionally, such a device has been used, for example, in U.S. Pat.
It is publicly known from the publication No.

(3) Problems to be Solved by the Invention In the prior art, a drive gear and a driven gear that have the same tooth width along the axial direction are meshed. However, there is a possibility that the driving gear and the driven gear may slightly shift in the axial direction, and if they shift, as mentioned above, if the tooth width is kept the same, the effective inner width will decrease, and the amount of wear on the tooth surface will decrease. may become larger, or abnormal noises may occur due to scratches that tend to occur at the corners of the teeth.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a balancer shaft drive device for an internal combustion engine that can always ensure an effective internal width of a driving gear and a driven gear.

+3. Arrangement of the Invention (1) Means for Solving the Problems According to the first feature of the present invention, the tooth width along the axial direction of the driving gear and the overlapping J gear has a width within the tooth width of the other side. A margin width is provided that accommodates the tooth width along the axial direction of the gear.

According to a second feature of the present invention, the driving gear and the driven gear are formed by integrating a gear body made of a material with a high Young's modulus with a cylindrical tooth portion made of a +4 material with a low Young's modulus.

(2) Effect 1] According to the above configuration, even if the driving gear and the driven gear move relative to each other in the axial direction, the effective inner width of both gears is ensured.

Further, according to the second feature, the gear body made of a material with a high Young's modulus has the strength to cope with the stress applied to the driving gear and the driven gear due to the bending stress applied to the rotating shaft from the wrapped transmission system. The teeth made of a material with a low Young's modulus can suppress the noise caused by meshing.

(3) Example Hereinafter, an example in which the present invention is applied to a DOHC type in-line four-cylinder internal combustion engine will be explained with reference to the drawings. First, in FIGS. 1, 2, 3, and 4, The engine body E is composed of a cylinder head 2 connected to the upper part of a cylinder block 1, an oil pan 3 at the lower part of the cylinder block, and a head cover 4 at the upper part of the cylinder head 2. be combined.

The cylinder block 1 includes an upper cylinder barrel portion 1a and a lower crankcase portion 1b, and is made of aluminum alloy. In the cylinder barrel part 1a,
Four cylinder bores 5 arranged in series are provided, and screws and screws 6 are slidably fitted into these cylinder bores 5, respectively. In addition, a plurality of journal bearings 7 are provided in the crankcase portion 1b at intervals along the arrangement direction of each cylinder bore 5, and each journal bearing is fixed to the surface of each journal bearing. bearing cap 8... and each of the journal bearings 7...
The crankshaft 9 is rotatably supported by the crankshaft 9, and the crank pins 9a of the crankshaft 9 and the respective pistons 6 are connected via connecting rods 10. Further, each of the bearing caps 8... is connected to the bridge member 1.
1 are connected together.

At one axial end of the crankshaft 9, an oil pump 12 driven by the crankshaft 9 is disposed on the outer side wall 1c of the cylinder block 1. This oil pump I2 includes a rotor 14 fixed to a crankshaft 9 within a pump case 13 attached to the side wall outer surface 1c of the cylinder block 1.
A leaner 17 is connected to the oil tank 1 through a suction pipe 16 to a suction port 15 provided in the pump case 13 . Also pump case 13
A discharge port 18 provided in the cylinder block 1 is connected to a lubricating oil passage 19 formed in the cylinder block 1 parallel to the crankshaft 9 . The other axial end of the crankshaft 9 projects slightly 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).

Referring to FIGS. 5 and 6 together, above the crankshaft 9 there are first and second balancer shafts 21 located at substantially symmetrical positions with respect to a vertical plane passing through the axis of the crankshaft 9. ．． 2
2 is rotatably arranged parallel to the crankshaft 9.

These balancer shafts 21 and 22 suppress secondary vibrations of the engine, and are inserted into the cylinder block 1 with one axial end protruding from the side wall outer surface 1c of the cylinder block 1. Both balancer shafts 21 and 22 have an eccentric portion 21 spaced apart from each other near the other end in the axial direction.
a, 21b; 22a, 22b, and the cylinder block 1 is provided with a pair of bearing holes 23 and 24 that support a portion of the first balancer shaft 21 near the other end in the axial direction, and A pair of bearing holes 25 and 26 that support a portion of the shaft 22 that is closer to the other end in the axial direction, and a bearing hole 2 that supports a portion of the second Haranza shaft 22 that is closer to one end in the axial direction.
7 is provided.

One end of the crankshaft 9 protrudes from the pump case 13 of the oil pump 12, and the first drive pulley 28 of the first winding transmission system T1 is attached to the protruding end of the crankshaft 9.
is fixed, and the second drive pulley 29 of the second winding transmission system T2 is fixed to the side farther from the cylinder block I than the first drive pulley 28, and both drive boots IJ28,
29 is rotationally driven in the direction shown by the arrow in FIG.

The first winding transmission system T1 includes an intake side valve cam 30 rotatably supported on the cylinder head 2 in parallel with the crankshaft 9 to drive the intake side valve mechanism, and an exhaust side valve mechanism. The cylinder head 2 is parallel to the crankshaft 9 for driving.
This is a timing transmission system for driving an exhaust side valve drive camshaft 31 rotatably supported by the cylinder block 1, and a water pump 32 attached to the side wall outer surface 1c of the cylinder block 1.
Drive boob IJ28, camshaft drive driven pulleys 33, 34 fixed to both camshafts 30, 31, respectively, water pump drive driven boob IJ35 fixed to pump shaft 32a of water pump 32, and each pulley 28. .33,
34. , 35, and a first timing belt 36 as an endless first transmission band.

In addition, the second winding transmission system T2, the first and second balancer shafts 2
1.22, which includes a second drive pulley 29, a driven booby IJ37 for reverse rotation that is interlocked and connected to the first balancer shaft 21, and a forward rotation drive that is fixed to the second balancer shaft 22. Drive driven pulley 38 and each boolean l729,
37. Endless second timing hell 1- suspended from 38
It consists of 39.

Referring to FIGS. 7 and 8 together, a gear case 42 serving as a 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 Haranza shaft 21. That is, the gear case 42 is
It is attached to the cylinder block 1 together with the pump case 13 by bolts 43. Said reverse drive driven boob IJ
37, the gear case 4 is parallel to the first paranza shaft 21.
A gear case 42 of a rotating shaft 44 rotatably supported by
It is fixed to the protruding end from. Moreover, the first balancer shaft 21
One end protrudes into the gear case 42 while being rotatably supported by the pump case 13.
3 and the gear case 42, a driven gear 41 fixed to the end of the balancer shaft 21 and a drive gear 40 provided at the inner end of the rotating shaft 44 are meshed with each other. Therefore, the power from the reverse drive driven pulley 37 is transmitted to the first balancer shaft 21 via the gears 4041 that mesh with each other. That is, both balancer shafts 21, 22 are driven to rotate in opposite directions.

The drive gear 40 includes a gear body 40a that is integrally provided on the inner end of the rotating shaft 44, and a tooth portion 40b that is press-fitted and fixed to the gear body 40a. The gear body 40a has a rotating shaft 44
It is integrally molded with a material having a high Young's modulus, such as chromium molybdenum (SCM).
0b is made of a material having a lower Young's modulus than the material of the gear body 40a, such as synthetic resin, cast iron, or iron-based sintered material, and is formed into a cylindrical shape with teeth on the outer peripheral surface.

The driven gear 41 includes a gear main body 41 fixed to the end of the first balancer shaft 21, and a tooth portion 41b press-fitted into the gear main body 41a. The gear body 4]a is made of a material having a high Young's modulus, such as chromium molybdenum steel (SCM), and has a cylindrical shape.
It is formed into a cylindrical shape with teeth on the outer peripheral surface using a material having a lower Young's modulus than that of the material.

Further, the tooth width D1 along the axial direction of the driving gear 40 is the same as that of the driven gear 4.
The tooth width D2 along the axial direction of the driven gear 41 is set larger than the tooth width D1. Moreover, the tooth width 1)
2b, margin width D2a on both sides of the tooth width corresponding to the tooth width D1;
D2b is set to exist.

Referring also to FIG. 9, a support shaft 45 parallel to the crankshaft 9 is implanted in the cylinder block 1 on both sides of the crankshaft 9. The support shaft 45 has a large diameter threaded portion 45a on the base end side and a threaded thread 45c having a smaller diameter than the large diameter threaded portion 45a.
A shaft portion 45b having a distal end thereof is coaxially connected via a flange portion 45d, and the flange portion 45
d in contact with the side wall outer body 1c, and the large diameter threaded portion 45
It is installed in the cylinder block 1 by screwing the parts a.

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

In the 10th and 11th figures, the first tensioner 46
, a plurality of balls 50 are interposed between an inner ring 48 supported by a shaft portion 45b of a support shaft 45 and an outer ring 49 in sliding contact with the outer surface of the first timing heald 36. A ring-shaped support member 51 press-fitted onto the outer surface of the base end has a pair of protrusions 51. a and 51b project outward on one diameter line. One protrusion 51a has a support hole 5.
A shaft 53 is fixed to the cylinder block 1 by penetrating the support hole 52, and the first tensioner
6 is swingably supported. The inner ring 48 has an arc-shaped elongated hole 54 centered on the shaft 53, and the shaft portion 4.5b of the support shaft 45 is inserted through the elongated hole 54. Further, 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, and the spring force of the first tension spring 55 causes the first
The outer ring 49 of the tensioner 46 is connected to the first timing heald 3.
6 from the outside, thereby applying a constant tension to the first timing belt 36.

The second tensioner 47 has a plurality of balls 5 between an inner ring 56 and an outer ring 58 that is in sliding contact with the second timing belt 39.
7 is interposed. Further, one end of a tension arm 59 which is rotatably supported by a shaft 60 fixed to the cylinder block 1 parallel to the crankshaft 9 is connected to the inner ring 56.
is fixed to.

Furthermore, an arc-shaped elongated hole 61 centered on the shaft 60 is bored in the center of the inner ring 56, and the shaft portion 45b of the support shaft 45 is inserted into the elongated hole 61. Further, a second tension spring 62 is stretched between the other end of the tension arm 59 and the cylinder block 1, and the spring force of the second tension spring 62 causes the outer ring 58 to be attached to the second timing heald 39 from the outside. The second timing belt 39 is pressed against the second timing belt 39, thereby applying a certain tension to the second timing belt 39. In this second tensioner 47, the width of the outer ring 58 is the same as that of the first tensioner 4.
The width is set smaller than the width of the outer ring 49 in No. 6.

Thus, the first timing belt 36 in the first winding transmission system T1 connects the loosened side between the first drive pulley 28 and the water pump driving driven pulley 35 to the first tensioner 46.
As the gear case 42 is pressed from the outside toward the inside, it curves deeply inward, and the gear case 42 is disposed in the empty space created by the curve. Moreover, the angle α between the direction in which the first timing belt 36 is pressed by the first tensioner 46 and the direction in which the second timing heald 39 is pressed by the second tensioner 47 is set to 90 degrees or more, preferably 120 degrees or more, for example 130 degrees. Ru.

The first winding transmission system T1 and the second winding transmission system T2 are covered by a side cover 65, and are connected to the support shaft 45.
The distal end thereof passes through the xide cover 65 and projects outward. Moreover, a nut 66 that is screwed onto the male threaded portion 45c at the tip of the support shaft 45 and comes into contact with the inner ring end surface of the second tensioner 47 is rotatably engaged with the Zide copper 65.
The nut 66 can be rotated from outside the side cover 65. Then, by tightening the nut 66, the first
The inner rings 48.degree. 56 of the second tensioners 46, 47 are movable relative to each other in a plane perpendicular to the axis of the support shaft 45 and abut against each other.

A rotating ring 67 that protrudes outward from the side cover 65 is fixed to the crankshaft 9, and a third drive pulley 68 of the third winding transmission system T3 is attached to the axially inner side of the rotating ring 67. and the fourth winding transmission system T4
A fourth drive pulley 69 is integrally provided on the axially outer side.

The third winding transmission system T3 is a transmission system for driving the AC generator 70 and air conditioner compressor 71 attached to the cylinder block I, and is fixed to the third drive pulley 68 and the input shaft of the AC generator 70. The driven pulley 72 for driving the AC generator 72, the driven pulley 73 for driving the combination type fixed to the input shaft of the air conditioner combiner 710, and each pulley [i8, 72 .
The fourth winding transmission system T4 is a transmission system for driving the power steering hydraulic pump 75 attached to the cylinder head 2. A fourth drive boo 1J69 and a hydraulic pump drive FJ fixed to the input shaft of the hydraulic pump 75.
It is composed of a J driven boob IJ76 and an endless belt 77 that is suspended around both pulleys 69 and 76.

Next, to explain the configuration of the lubrication oil supply system, an oil pump 12 is connected to the lubrication oil passage 19 provided in the cylinder block 1.
The lubricating oil supplied from the oil filter 80 is guided to an oil filter 80 attached to the side surface of the cylinder block 1 at a portion corresponding to the journal bearing 7 located between the two inner cylinder bores 5, 5 along the arrangement direction. Furthermore, the cylinder block 1 includes an oil passage 81 that guides the lubricating oil from the oil filter 80 upward toward the valve mechanism side, and an oil passage 82 that guides the lubricating oil downward.
and are drilled.

On the other hand, the bridge member 11 that interconnects the bearing caps 8... has a central oil passage 83 corresponding to the crankshaft 9.
and each balancer shaft 21, 22 on both sides of the central oil passage 83.
Side oil passages 84 and 85 respectively corresponding to the lateral oil passages 84 and 85 are bored parallel to the crankshaft 9.

In addition, each of the oil passages 83 and 8 is provided in the bridge portion + and I'll.
A communication oil passage 86 for communicating the oil passages 83 to 85 with each other is bored at a longitudinally intermediate portion of each of the oil passages 83 to 85 so as to be orthogonal to each of the oil passages 83 to 85.

The bridge member 11 and each bearing cap 8...
In order to supply lubricating oil to the supporting portion of the crankshaft 9, oil supply passages 87 are formed, each extending upward and communicating with the central oil passage 83 at its lower end. Also, the bearing hole 23.2 of the balancer shaft 21
4, the bridge member 11, the bearing cap 8, and the cylinder block 1 have a lower end connected to a side oil passage 84.
Oil supply passages 88 and 88 are drilled to communicate with the upper ends of the bearing holes 23 and 24, respectively. An oil supply passage 89 that communicates with the side oil passage 84 extends downward and is bored, and the oil supply passage 89 communicates with an oil supply passage 90 that is bored in the pump case 13 .

This oil supply path 90 is connected to the balancer shaft 2 in the pump case 13.
1 bearing part, and also communicates with the rotary shaft 44 bearing part in the gear case 42. Bearing hole 2 of balancer shaft 22
5, 26, and 27, the bridge member 11,
The bearing cap 8 and the cylinder block 1 have a lower end communicating with the side oil passage 85 and an upper end communicating with the bearing hole 25,
26 and 27, respectively, are drilled therein.

Oil passage 82 that guides lubricating oil from oil filter 80 downward
For example, the portion corresponding to the bearing hole 24 communicates with the intermediate portion of the oil supply passage 88 , and therefore the lubricating oil from the oil filter 80 flows through the oil supply passage 88 to each oil passage 83 , 84 . , 85.

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

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 heald 39 connected to the second winding transmission system T2 is supported by a common support shaft 45, the tensioner arrangement can be made compact. can. Moreover, in the first winding transmission system T1, the valve drive camshaft 30 requires a large amount of driving force.
31 and water pump 32, the second
Although a larger driving load acts on the wrapped transmission system T2, since the first tensioner 46 is supported by the support shaft 45 with the first tensioner 46 axially inward than the second tensioner 47, the support shaft 4
The load applied to the tip side of 5 can be minimized.

Also, the angle α formed by the pressing direction by the first and second tensioners/16.47 should be set to 90 degrees or more, preferably 120 degrees or more.
By setting it to -, the direction of the load applied to the support shaft 45 can be shifted and the overall load can be kept small. The load applied to 45 can be further suppressed.

Furthermore, the load on the second winding transmission system T2 is increased by the first winding transmission system T1.
Since the load is smaller than the load of It is possible to reduce the amount of protrusion and contribute to making the entire engine more compact.

Furthermore, the tooth width D2 of the driven gear 41 is provided with margins D2a and D2b that accommodate the tooth width D1 of the driving gear 40 within the tooth width D2, so that the driving gear 40 and the driven gear 11 can move relative to each other in the axial direction. However, the effective contact width of both gears 40, 4] can be ensured, and it is not necessary to strictly define dimensional accuracy. Furthermore, since both gears 40, 41 consist of gear bodies 40a, 4], a made of a material with a high Young's modulus, and tooth portions 40b, 41b made of a material with a low Young's modulus, they act in a direction perpendicular to the axis of rotation. While ensuring the strength against the bending stress of the gear bodies 40a, 41a, it is possible to suppress the generation of noise due to meshing as much as possible.

According to the first feature of the present invention as described in "C8 Effects of the Invention" (2), the tooth width along the axial direction of one of the driving gear and the driven gear has a width within the tooth width along the axial direction of the other gear. Since a margin is provided to accommodate the tooth width along the tooth, even if there are variations in dimensional accuracy or relative movement in the axial direction of both gears, the effective contact width is ensured and prevents increased wear on the tooth surface and generation of abnormal noise. can do.

According to the second feature of the present invention, the driving gear and the driven gear are formed by integrating a cylindrical tooth portion made of a material with a low Young's modulus into a gear body made of a material with a high Young's modulus. The gear body can have the strength to withstand the stress applied to the gear and the driven gear, while suppressing the generation of noise caused by meshing.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional side view, FIG. 2 is a view taken along the line ■-■ in FIG. 1, and FIG.
Figure 4 is a sectional view taken along the line ■-■ in the figure.
A cross-sectional view taken along the line V-IV, Figure 5 is a cross-sectional view taken along the ■-V line in Figure 3,
6 is a sectional view taken along the line VI-VI in FIG. 3, FIG. 7 is an enlarged sectional view taken along the line ■-■ in FIG. 3, FIG. 8 is an enlarged sectional view taken along the line ■-■ in FIG. 3, and FIG. is a sectional view taken along the line IX-IX in Figure 2, No. 10
The figure is a plan view of the 1st tensioner, and Figure 11 is the 10th x
It is a sectional view taken along the r-xi line. 9... Crankshaft, 21... Balancer shaft, 21a. 21b... Eccentric weight part, 40... Drive gear, 40a
41a... Gear body, 40b b... Teeth,... Driven gear, 42... Gear case as a case member, 44... Rotating shaft, DI. D2...Face width E...Engine body T2...Wrap transmission system Patent applicant Honda Motor Co., Ltd. Agent B1 Physician Ken Ochimu Takahide Tanaka Figures 9 and 10 11 Procedural amendment (formality) June 1, 1989, Japanese Patent Application No. 1-34455 Name of the invention Relationship with the case of person who amends the balancer shaft drive device of an internal combustion engine Patent applicant

Claims (2)

[Claims] (1) A balancer shaft having an eccentric weight part is rotatably supported by the engine body, and a drive gear is attached to one end of the rotary shaft which is rotatably supported in parallel to the balancer shaft by a case member attached to the engine body. A balancer shaft drive device for an internal combustion engine in which a driven gear that meshes with the drive gear is fixed to the balancer shaft, and the other end of the rotating shaft is interlocked and connected to the crankshaft via a winding transmission system. A balancer shaft drive device for an internal combustion engine, characterized in that the tooth width along the axial direction of one of the gear and the driven gear is provided with a margin that accommodates the tooth width along the axial direction of the other gear within the tooth width. . (2) The driving gear and the driven gear according to item (1), wherein the cylindrical tooth portion made of a material with a low Young's modulus is integrated with a gear body made of a material with a high Young's modulus. Balancer shaft drive device for internal combustion engines.