JP2006316625A - Vibration reducer of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary balancer 42 for remarkably reducing weight of a balancer weight 50. <P>SOLUTION: In the secondary balancer 42, the balancer weight 50 having respectively predetermined mass is arranged on a pair of balancer shafts 48 for mutually rotating in the inverse direction at a speed of two times that of a crankshaft 24. This secondary balancer 42 is arranged in a just under position of a cam sprocket 40 in front of an angle more than a front wall 34 of an internal combustion engine 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration reduction device for an internal combustion engine including a balancer that reduces rotational vibration of the internal combustion engine.

2. Description of the Related Art In an internal combustion engine mounted on a vehicle, particularly an in-line multi-cylinder internal combustion engine, a secondary balancer is provided to reduce secondary vibration caused by piston reciprocation. As is well known, this secondary balancer has a pair of balancer shafts that rotate in opposite directions at a speed twice that of the crankshaft, and each balancer shaft is provided with a balancer weight having a predetermined mass. . Such a secondary balancer is conventionally arranged inside an internal combustion engine, and generally as described in Patent Document 1, it is easy to lubricate and has a relatively large space inside a crankcase or an oil pan. And was supported by a cylinder block and an oil pan using a ladder frame and a bracket.
JP 2003-130136 A

  Generally, in an internal combustion engine mounted on a vehicle, a transmission is connected to the rear of the internal combustion engine, and a power train including the internal combustion engine and the transmission is supported on the vehicle body side at several locations. Accordingly, the position of the center of gravity of the powertrain including the internal combustion engine is located relatively toward the rear of the engine, and is typically offset to the rear of the engine from the center position of the secondary inertia force of the crank rotation system of the internal combustion engine. . Since the moment of the secondary inertia force with respect to the center of gravity position appears as secondary vibration of the internal combustion engine, the mass of the balancer weight required to cancel this moment is also the position of the balancer weight, that is, the moment from the center of gravity position. Varies with arm length. Specifically, the mass of the balancer weight can be reduced as far as possible from the position of the center of gravity to the front of the engine.

  However, in the conventional layout in which the balancer weight is disposed inside the internal combustion engine as described above, the balancer weight requires a relatively large mass, and the balancer cannot be sufficiently reduced in size and weight. In addition, as described above, the configuration in which the balancer weight is disposed in the oil pan has a problem that the amount of lubricating oil that interferes with the rotating balancer weight and the like is large and the loss thereof is large.

  The present invention has been made paying attention to such points, and has as its main object to provide a novel vibration reduction device for an internal combustion engine that can significantly reduce the weight and size of a balancer.

  A balancer shaft that is arranged in parallel with the crankshaft of the internal combustion engine and rotates in conjunction with the crankshaft, and a balancer weight provided on the balancer shaft and having a predetermined mass is provided. At least the balancer weight is disposed in front of the engine with respect to the front wall of the internal combustion engine.

  According to the present invention, the balancer weight can be remarkably reduced in weight by disposing the balancer weight ahead of the front wall of the internal combustion engine, and thus the balancer can be significantly reduced in weight and size. .

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the present specification, the left-right direction of FIG. 1 that is the axial direction of the crankshaft 24 is the (engine) longitudinal direction La, and the up-down direction of FIG. 1 that is the reciprocating direction of the piston 12 is the (engine) vertical direction Lb. , The direction perpendicular to the paper surface of FIG. 1, which is a direction perpendicular to Lb, is referred to as (engine) width direction Lc, and the right side of FIG. The left side of FIG. 1 on the side and the opposite side is referred to as the (engine) front side. Further, components provided on the intake valve side and the exhaust valve side of the internal combustion engine 10, such as the camshaft 28, are appended with “I” after the reference numerals as necessary. The components on the exhaust valve side are denoted by “E” after the reference numerals.

  Referring to FIG. 1, an automatic transmission 2 is disposed on the rear side of an internal combustion engine 10 for a vehicle. A power train including the internal combustion engine 10 and the automatic transmission 2 is connected to an engine-side mounting 4 and a shift. It is supported on the vehicle body side at several places including the machine side mounting 6.

  The internal combustion engine 10 is an in-line four-cylinder type in which four pistons 12 are arranged in series along the longitudinal direction of the engine (cylinder row direction) La. A cylinder block 16 in which a (cylinder) 14 is formed, an oil pan 18 which is attached to the lower side of the cylinder block 16 and stores lubricating oil, a cylinder head 20 fixed on the upper side of the cylinder block 16, And a head cover 22 attached to the upper side of the cylinder head 20. A crankshaft 24 is rotatably supported on the cylinder block 16, and a crankpin of the crankshaft 24 and the piston 12 are connected by a connecting rod 26.

  The intake camshaft 28I and the exhaust camshaft 28E are direct-acting types provided with cams 30 that directly press and drive the valve lifters of the intake / exhaust valves, and the head of the piston 12 is parallel to the crankshaft 24. The cylinder head 20 extends in the cylinder row direction La and is rotatably supported between the cylinder head 20 and the head cover 22.

  A front cover 36 is attached to the front wall 34 of the internal combustion engine 10. The front wall 34 includes the cylinder block 16, the oil pan 18, the cylinder head 20, the head cover 22, and the like. A crank sprocket 38 fixed to the front end of the crankshaft 24 and a cam sprocket 40 fixed to the front end of the camshaft 28 are disposed in the front cover 36 formed between the front wall 34 and the front wall 34. Yes. A chain 32 for transmitting rotational power is wound around these sprockets 38 and 40. The rotational power of the crankshaft 24 is transmitted to the camshaft 28 through the endless chain 32, and the camshaft 28 rotates at half the speed of the crankshaft 24.

  As shown in FIGS. 1 to 4, in the first embodiment of the present invention, as a balancer that reduces and cancels vibrations of the internal combustion engine in front of the engine front wall 34 (to the left in FIG. 1), A secondary balancer 42 for reducing and canceling secondary vibration of the internal combustion engine is disposed. The secondary balancer 42 is supported by a pair of shaft supports 46 fixed to the front wall 34 of the cylinder head 20 by fixing bolts 44, and is rotatably supported by the shaft supports 46. And a pair of metallic cylindrical balancer shafts 48 extending along the direction La. A balancer weight 50 having a predetermined mass and a balancer side gear 52 are provided on the outer periphery of the balancer shaft 48.

  As shown in FIG. 2, the balancer shaft 48 and the balancer weight 50 are arranged inside the chain 32 and directly below the cam sprocket 40 of the pair of camshafts 28 and adjacent to each other in the engine width direction Lc. ing. That is, the intake side balancer shaft 48I is disposed obliquely below the intake camshaft 28I, and the exhaust side balancer shaft 48E is disposed obliquely below the exhaust camshaft 28E. That is, the secondary balancer 42 is disposed between the crankshaft 24 and the camshaft 28 in the engine up-down direction and closer to the engine upper side than the crankshaft 24 and closer to the camshaft 28.

  As shown in FIGS. 2 and 3, each cam sprocket 40 is fixed to the front end of the camshaft 28 protruding from the front wall 34 of the cylinder head 20 by a fixing bolt 54. A cam-side chain gear 56 around which the chain 32 is wound is provided on the outer periphery of each cam sprocket 40. A cam side gear 58 that meshes with the balancer side gear 52I is provided on the outer periphery of one intake cam sprocket 40I adjacent to the cam side chain gear 56I in the axial direction. These gears 58I and 52I constitute a gear train that transmits rotational power from one intake camshaft 28I to the corresponding intake-side balancer shaft 48I. These gears 58I and 52I are resin gears using a synthetic resin in order to reduce rattling noise called so-called rattling noise. Alternatively, a scissor gear may be used instead of the resin gear.

  As shown in FIG. 4, the pair of balancer side gears 52I and 52E mesh with each other, and rotational power is transmitted from the intake side balancer shaft 48I to the exhaust side balancer shaft 48E via these gears. Through these gears, both balancer shafts 48 rotate in opposite directions at a rotational speed twice that of the crankshaft 24.

  Referring to FIG. 3, an oil supply passage 60 formed over the cylinder head 20, the shaft support 46, and the like in the bearing portion between the outer peripheral surface of the shaft support 46 and the inner peripheral surface of the balancer shaft 48, which is a metal contact portion. Through which lubricating oil is supplied.

  The front cover 36 is integrally formed with a protrusion 62 that protrudes from the back side to the rear of the engine (the right side in FIG. 3). The protrusion 62 is disposed above the balancer 42 with a predetermined gap 64 therebetween, and has a semicircular arc shape that covers the balancer 42 above the engine.

  As shown in FIG. 2, in the meshing portion 53 where the balancer side gears 52 of two adjacent balancer shafts 48 mesh with each other, the rotational directions (tangential directions) 55I and 55E of the shafts 48 are set so as to be directed upward of the engine. A passage forming portion 66 through which blow-by gas can flow is set at an upper position of the meshing portion 53 as indicated by an arrow 70. In other words, the protrusion 62 is not provided above the meshing portion 53, that is, a notch-shaped passage forming portion 66 is formed in the protrusion 62.

  Next, the characteristic configuration and operational effects of the present embodiment will be described. Referring to FIG. 1, the center position 78 of the secondary inertia force (secondary vibration component) of the crank rotation system of the internal combustion engine 10 is located substantially at the center of the internal combustion engine 10 in the engine longitudinal direction La. The power train including the internal combustion engine 10 and the automatic transmission 2 is supported on the vehicle body side by the engine side mounting 4 and the transmission side mounting 6. Therefore, in general, the center of gravity position 76 of the powertrain is offset or biased toward the rear side of the engine (the right side in FIG. 1) as compared with the center position 78 of the secondary inertia force.

  Since the moment of the secondary inertia force (the center position 78) with respect to the center of gravity position 76 appears as the secondary vibration of the internal combustion engine 10, the mass of the balancer weight necessary to cancel this changes with the distance from the center of gravity position 76. In other words, the weight of the balancer weight can be reduced as the balancer weight is moved further forward of the engine.

  In the comparative example as the prior art, a balancer weight 74 is accommodated in the oil pan 18 (see FIG. 1). On the other hand, in the present embodiment, the entire balancer 42 including the balancer weight 50 is disposed in front of the engine with respect to the front wall 34 of the internal combustion engine 10. Therefore, with respect to the secondary balancer in which the pair of balancer shafts 48 rotate in opposite directions at twice the rotational speed of the crankshaft 24, in this embodiment, the balancer weight 50 is sufficiently arranged in front of the engine. As a result, in this embodiment, the weight of the balancer weight 50 can be reduced to, for example, half or less as compared with the comparative example. Thus, since the balancer weight 50 can be remarkably reduced in weight, the entire balancer 42 can be remarkably reduced in weight and size. For this reason, for example, the shaft support 46 can be reduced in size and weight, and with such weight reduction, the driving horsepower can be reduced, and the load and load on the gear and the like can be remarkably reduced.

  The balancer 42 is between the camshaft 28 and the crankshaft 24, and is closer to the upper part of the engine closer to the camshaft 28 than the crankshaft 24, more specifically, at a position directly below the pair of camshafts 28. Has been placed. Thus, since the balancer 42 itself is small and the balancer 42 can be disposed in the vicinity of the camshaft 28 having a relatively large space, the engine mountability of the balancer 42 is significantly improved. Further, since the balancer 42 is disposed at a position avoiding the oil pan 18, compared with the case where the balancer weight 74 (see FIG. 1) is disposed in the oil pan 18 as in the comparative example, the balancer 42 is not Interference can be greatly reduced, and friction caused by this lubricating oil can be greatly reduced. In particular, since the friction at the start of the cryogenic temperature is greatly reduced, it is possible to reduce the output and the size of the starter that rotationally drives the crankshaft at the start.

  The balancer side gears 52 that mesh with each other are provided on the pair of balancer shafts 48. The pair of balancer side gears 52 can reliably rotate the balancer shafts 48 in opposite directions with a simple structure. The one balancer side gear 52I meshes with a cam side gear 58 provided on one of the intake camshaft and the exhaust camshaft 28I. That is, one balancer side gear 52I meshes with both the other balancer side gear 52E and the cam side gear 58, and simplification of the gear mechanism from the camshaft to both balancer shafts is achieved.

  As shown in FIG. 2, the cam side gear 58 is provided on the outer periphery of the cam sprocket 40 around which the power transmission chain 32 is wound, that is, adjacent to the gear 56 around which the chain 32 is wound in the axial direction. It is arranged on the outer periphery of the cam sprocket 40. Thus, by providing the cam side gear 58 in the existing cam sprocket 40, effects such as weight reduction, size reduction, and space saving can be obtained.

  The balancer 42 is housed and disposed inside a front cover 36 attached to the front wall 34 of the internal combustion engine 10, and a protrusion 62 protruding from the back surface of the front cover 36 is disposed above the balancer 42. The protrusion 62 can effectively suppress the oil mist from being scattered by the rotating balancer 42.

  As shown in FIG. 2, the rotation directions 55I and 55E of the pair of balancer side gears are set so as to be directed upward of the engine at the portion 53 where both gears mesh with each other. A passage forming portion 66 through which gas can flow is formed. That is, the passage forming portion 66 is notched in the protrusion 62 so as to release the upper portion of the meshing portion 53. Therefore, as shown by an arrow 70 in FIG. 2, blow-by gas generated from the crankcase on the lower side of the engine is actively guided to the head cover side above the engine using the rotations 55I and 55E of the two balancers. Oil deterioration can be suppressed. Further, as indicated by an arrow 72, the lubricating oil can be returned from the engine upper side toward the engine lower side through the passage forming portion 66. That is, the passage forming portion 66 constitutes a part of the oil dropping path from the cylinder head 20 side to the oil pan 18 side.

  Each balancer weight 50 has a substantially fan shape centered on the balancer shaft 48 when viewed in the axial direction shown in FIG. 2. In this embodiment, the balancer weight 50 has a disk shape that is approximately half the length in the circumferential direction. The weights of both balancer weights 50 and the center of gravity in the axial direction are set to be the same. Then, as shown in FIG. 4, the balancer weight 50I on one intake side has a plate-like shaft of the balancer weight 50E on the other exhaust side so that both balancer weights 50 partially overlap in the radial direction. It has sandwiching piece portions 88 located on both sides in the direction, and has a substantially U-shaped section, a substantially U-shaped section, and a channel shape. That is, the outer periphery of the plate-like balancer weight 50E is surrounded by the outer periphery of the balancer weight 50I having a channel shape with a predetermined gap. Accordingly, the balancer weights 50I and 50E can be disposed sufficiently close to each other while the center of gravity positions of the balancer weights 50I and 50E are matched in the axial direction, and space saving can be achieved.

  As described above, since the balancer 42 can be sufficiently reduced in weight, the gears 58I and 52I for transmitting rotational power to the balancer shaft can be resin gears using synthetic resin. Thereby, the rattling sound called a so-called rattling sound can be remarkably reduced. Further, a scissor gear may be used instead of the resin gear.

  In the embodiment described below, only differences from the above-described embodiment will be basically described, and the same components as those in the above embodiment will be denoted by the same reference numerals, and redundant description will be appropriately omitted.

  5 to 8 correspond to the first to fourth embodiments of the present invention, respectively. In any of the embodiments, the balancers 42, 42 </ b> A, 42 </ b> B, 42 </ b> C are arranged in front of the engine with respect to the front wall 34 of the internal combustion engine 10. In the first embodiment shown in FIG. 5, a pair of balancer weights 50 are arranged immediately below the pair of cam sprockets 40 as shown in FIGS.

  In the balancer 42A of the second embodiment shown in FIG. 6, a pair of balancer weights 50 are disposed immediately below the crank sprocket 38, and one exhaust side balancer side gear 52E of the balancer side gears 52E, 52I meshing with each other is a crank. By meshing with a crank side gear 80 provided on the sprocket 38, both balancer shafts 48I and 48E are set to rotate in opposite directions to each other at twice the speed of the crankshaft.

  In the third embodiment shown in FIG. 7, a balancer 42B is arranged just below the two cam sprockets 40, as in the first embodiment. However, the chain 32A wound around the crank sprocket 38 is wound around one exhaust side balancer shaft 48E of the pair of balancer shafts 48I and 48E instead of the cam sprocket 40 as in the first embodiment. Rotational power is transmitted from the side balancer shaft 48E to the other intake side balancer shaft 48I and the pair of camshafts 28 through an appropriate gear mechanism.

  In the balancer 42C of the fourth embodiment shown in FIG. 8, in addition to the first chain 32 wound around the crank sprocket 38 and the cam sprocket 40 as in the first embodiment, the crank sprocket 38 as in the third embodiment. And a second chain 32A wound around one exhaust-side balancer shaft 48E of the pair of balancer shafts 48I and 48E, and the rotational power of the crankshaft is transmitted to the balancer shaft via the second chain 32A. It is like that. According to this embodiment, the balancer 42C has a higher degree of freedom in layout than the one in which the balancer shaft is linked to the camshaft or crankshaft by a gear mechanism as in the first to third embodiments. As shown in FIG. 8, the balancer 42 </ b> C can be disposed at a substantially intermediate position spaced from both the crank sprocket 38 and the cam sprocket 40.

  In the secondary balancer, it is necessary to rotate the balancer shaft at a rotational speed twice that of the crankshaft. On the other hand, the camshaft rotates at half the rotational speed with respect to the crankshaft. Therefore, in the configuration in which the cam side gear and the balancer side gear are directly meshed as in the first embodiment, the configuration is simplified, but the gear ratio between the cam side gear and the balancer side gear is large, and the layout, etc. The application may be difficult.

  Therefore, in the fifth embodiment shown in FIGS. 9 and 10, an intermediate gear mechanism 82 for accelerating the balancer side gear 52I with respect to the cam side gear 58 provided on one intake camshaft is provided. . The intermediate gear mechanism 82 includes a first intermediate gear 84 that meshes with the cam-side gear 58 and a second intermediate gear 86 that meshes with the balancer-side gear 52I. Both gears 84 and 86 are arranged coaxially and are integrated. It is constituted so that it may rotate. The second intermediate gear 86 has a larger diameter than the first intermediate gear 84 and a large number of teeth (for example, four times).

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above embodiments, and includes various modifications and changes without departing from the spirit of the present invention. For example, although the cam side gear 58 is provided on the intake side cam sprocket 40I in the first embodiment, the cam side gear 58 may be provided on the exhaust side cam sprocket 40E.

The block diagram which shows simply the internal combustion engine to which the vibration reduction apparatus which concerns on this invention is applied. BRIEF DESCRIPTION OF THE DRAWINGS The front corresponding | compatible figure which shows the vibration reduction apparatus of the internal combustion engine which concerns on 1st Example of this invention. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. The front corresponding view which shows the layout of the said 1st Example typically. The front corresponding figure which shows typically the layout of 2nd Example of this invention. The front corresponding view which shows typically the layout of 3rd Example of this invention. The front corresponding view which shows typically the layout of 4th Example of this invention. The front corresponding view which shows typically the layout of 5th Example of this invention. FIG. 10 is a cross-sectional view taken along line XX in FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine 28 ... Cam shaft 32 ... Chain 34 ... Front wall 36 ... Front cover 38 ... Crank sprocket 40 ... Cam sprocket 42 ... Secondary balancer 48 ... Balancer shaft 50 ... Balancer weight 52 ... Balancer side gear 58 ... Cam side gear 62 ... Projection part 66 ... Passage formation part 82 ... Intermediate gear mechanism

Claims (11)

A balancer shaft disposed in parallel with the crankshaft of the internal combustion engine and rotating in conjunction with the crankshaft; and a balancer weight provided on the balancer shaft and having a predetermined mass;
The vibration reduction device for an internal combustion engine, wherein at least the balancer weight is disposed in front of the engine with respect to the front wall of the internal combustion engine.   2. The vibration reduction device for an internal combustion engine according to claim 1, wherein the balancer is a secondary balancer in which a pair of balancer shafts rotate in directions opposite to each other at twice the rotational speed of the crankshaft.   The vibration reduction device for an internal combustion engine according to claim 2, further comprising a balancer side gear that meshes with the pair of balancer shafts.   4. The vibration of the internal combustion engine according to claim 3, wherein the pair of balancer shafts are arranged side by side in the engine width direction and are arranged on the upper part of the engine in the vicinity of the camshaft that drives the intake and exhaust valves. Reduction device.   5. The vibration reduction device for an internal combustion engine according to claim 3, wherein one balancer side gear meshes with a cam side gear provided on one of the intake camshaft and the exhaust camshaft.   A cam-side gear provided on one of the intake camshaft and the exhaust camshaft, and an intermediate gear mechanism for accelerating one balancer-side gear with respect to the cam-side gear. 5. The vibration reduction device for an internal combustion engine according to 3 or 4. A chain for power transmission is wound around the crank sprocket of the crankshaft and the cam sprocket of the camshaft,
The vibration reducing device for an internal combustion engine according to claim 5 or 6, wherein the cam side gear is provided on an outer periphery of the cam sprocket. Each of the pair of balancer weights of the secondary balancer has a substantially fan shape centered on the balancer shaft.
The center of gravity of both balancer weights is set to the same axial position,
In addition, one balancer weight has clamping pieces located on both sides in the axial direction of the other balancer weight forming a plate shape so that both balancer weights partially overlap in the radial direction. Item 8. The vibration reduction device for an internal combustion engine according to any one of Items 3 to 7.   The secondary balancer is accommodated and disposed inside a front cover attached to the front wall of the internal combustion engine, and a protrusion protruding from the back surface of the front cover toward the engine rear side is disposed above the secondary balancer. 9. The vibration reduction device for an internal combustion engine according to claim 3, wherein the vibration reduction device is an internal combustion engine. The rotation direction at the portion where the pair of balancer side gears mesh with each other is set so as to be directed above the engine,
10. The vibration reducing device for an internal combustion engine according to claim 3, wherein a passage forming portion through which blow-by gas can flow is formed above the meshing portion of the engine.   The vibration reduction device for an internal combustion engine according to any one of claims 3 to 10, wherein the balancer side gear is a resin gear using a resin material.

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