KR100570723B1 - V-shaped internal combustion engine - Google Patents

Abstract

First and second gears are interposed between the first and second endless power transmission belts and the crankshaft 7, respectively, which drive the cam shafts of the cylinder heads of the V-shaped cylinder banks, respectively. A pair of balancer shafts in a position symmetrical with respect to the separation plane acting as a center, where the upper and lower blocks of the cylinder block are spaced from each other from a horizontal plane passing through the center of the crankshaft such that the axes of the balancer shaft pair are parallel to the crankshaft. Is placed. The crankshaft and the balancer shaft on the lower block side are connected to each other by a third endless power transmission belt. The balancer shafts are connected to each other by a third gear so that the balancer shaft pairs are driven to rotate in opposite directions to each other. Thus, the first and second endless power transmission belt and the third endless power transmission belt are prevented from overlapping each other in the axial direction of the crankshaft. In particular, each endless power transmission belt and each gear are each disposed on a respective plane crossing at right angles to the axis of the crankshaft, thereby preventing the engine from extending in the axial direction of the crankshaft.

Description

V-shaped internal combustion engine

1 is a plan view of the crank pulley side of the V-type internal combustion engine according to the present invention.

2 is an enlarged view of a main part of FIG. 1;

3 is an enlarged view of another main part of FIG. 1;

4 is an enlarged view of still another main part of FIG. 1;

<Explanation of symbols for the main parts of the drawings>

1: upper block 2: lower block

3: oil pan 4a, 4b: cylinder head

5a, 5b: Camshaft 6a, 6b: Head cover

7: crankshaft 8: compressor

9: generator 10: crank sprocket

11: Drive pinion 12a, 12b: Deceleration driven pinion

13a, 13b: Sprocket 14a, 14b: Cam Sprocket

15a, 15b, 19: Silent chain 16a, 16b: Balancer shaft

17 balancer shaft sprocket 18 pump pump

20a, 20b: gear 22-24: chain tensioner

25-28: Chain Guide E: Engines

The present invention relates to a V-type internal combustion engine, and more particularly, to an internal combustion engine having a balancer device that cancels secondary vibromotive force.

Conventionally, each includes a timing chain for connecting a sub-chain for driving a balancer device, an oil pump, a water pump and the like and a valve cam on a cylinder head and a crankshaft for driving it (for example, Japanese Unexamined Patent) Published So 62-233423 Many institutions have been proposed.

For example, in a four-cycle V-shaped 8-cylinder engine with banks forming a 90-degree angle (formed between the V-shaped banks of cylinders), a planar crank with the center of the plane crankshafts of all crank pins is in the same plane. The operation cycles of the two cylinder banks are shifted 180 degrees, with alternating explosions occurring in each cylinder bank. According to this configuration, the planar crank configuration has the advantage of achieving high power because it does not cause any interference and explodes in one bank of banks at regular intervals. On the other hand, in a V-shaped eight-cylinder engine employing a planar crank, secondary imbalance is generated by the inertial force generated by the reciprocating motion of the engine. While the secondary imbalance is occurring, the direction of inertial force generated in this way becomes similar to the inertial force generated when the conventional tandem four-cylinder engine is horizontal when the engine is viewed as a whole. Therefore, the imbalance described above employs the theory of secondary balancers for conventional tandem four-cylinder engines, dividing the banks forming the angles and placing them in positions symmetrical with respect to the horizontal plane acting as the center passing through the center of the crankshaft. It can be compensated by rotating the two balancer shafts in opposite directions to each other (see Japanese Unexamined Patent Publication No. Hei 8-193648).

When providing the balancer described above in a V-type eight cylinder engine employing a flat crank, as shown in Japanese Unexamined Patent Publication No. Hei 8-193648, it is actually the lower part of one of the cylinder heads to be driven by a subchain. Install the balancer on the side.

On the other hand, since the two cylinder heads are relatively largely spaced apart from each other by a V-shaped engine having a bank that forms a 90 degree angle, the crankshaft and the respective cylinder heads for each endless power transmission timing belt are usually Install in between. In this case, the balancer is naturally arranged so as not to interfere with the endless power transmission timing belt. However, when the balancer is driven by the chain, the driver chain must be arranged so as not to interfere with the endless power transmission timing belt.

Accordingly, the pulley or sprocket must be tripled on the crankshaft, and the engine tends to extend in the axial direction of the crankshaft. This is the first problem of the prior art.

However, normally, the guide for valve cam drive timing chain and the guide for sub chain are provided separately. In this case, the chains are separated so as not to interfere with each other, and the chain guides need to be unnecessarily large in order to fix the support for them, which results in a problem that the size of the engine becomes large and heavy. This is the second problem of the prior art.

The present invention is intended to solve the inherent problems of the prior art.

It is an object of the present invention to provide a V-type internal combustion engine having a balancer device that can be minimized to be mounted on a mass production vehicle.

According to the present invention, the above object is to provide a V-type internal combustion engine having a balancer device,

Crankshafts;

A V-shaped cylinder bank having a bank forming an angle of 90 degrees;

A first endless force transmission belt for driving a first camshaft member installed on the cylinder head of one of the V-shaped cylinder banks;

A first gear interposed between the first endless power transmission belt and the crankshaft;

A second endless power transmission belt for driving a second camshaft member installed on a cylinder head of another bank of the V-shaped cylinder banks;

A second gear interposed between the second endless power transmission belt and the crankshaft;

A pair of balancer shafts that rotate in opposite directions and extend in parallel to the crankshaft;

A pair of third gears driving each of the pair of balancer shafts; And

A third power transmission belt connecting one of the crankshaft and the balancer shaft, the third power transmission belt being disposed at a position outside the area in contact with the first and second endless power transmission belts on a plane perpendicular to the axial direction of the crankshaft; It is achieved by a V-type internal combustion engine.

In the above arrangement, the crankshaft comprises a planar crank in which the axial centers of all the crankpins of the cylinders concerned lie in a common plane, wherein the V-shaped cylinder bank has an upper block and The lower block includes a cylinder block spaced apart from each other, one of the balancer shaft pair disposed on the lower block side is connected to the crankshaft through the third endless power transmission belt, and the upper block side The other one of the balance shaft pairs is preferably connected to the one of the balance shaft pairs by being geared to each other with the third gear pair such that the balance shaft pairs rotate in opposite directions.

The object can also be achieved by a V-shaped engine balancer device with a planar crank installed with a bank in which the centers of all crank pins are in the same plane and form a 90 degree angle, according to a first aspect of the invention, wherein Each of the first and second gears 12 is interposed between the first and second endless power transmission belts (chains 15) that drive the camshaft and the crankshaft 7 on the cylinder head of each of the V-shaped cylinder banks, respectively. Center the crankshaft 7 so that the axes of the pair of balancer shafts 16a, 16b are parallel to the crankshaft 7 so that the balancer shafts 16a, 16b are rotated in opposite directions. A pair of balancer shafts 16a, 16b is installed at a position symmetrical with respect to the separation plane acting as a center, in which the upper block 1 and the lower block 2 of the cylinder block are spaced from each other from the horizontal plane passing therethrough, and the crank The balancer shaft 16b on the shaft 7 and the lower block 2 are connected to each other by a third endless power transmission belt (chain 19), and the balancer shaft 16b and the upper block on the lower block 2 side The balancer shafts 16a on the side are connected to each other by the third gears 20a and 20b so that the pair of balancer shafts 16a and 16b are driven to rotate in opposite directions to each other. According to this configuration, the first and second endless power transmission belts for driving the balancer shaft are prevented from overlapping each other in the axial direction of the crankshaft, whereby the extension of the engine in the axial direction of the crankshaft can be prevented. . In particular, by arranging the first to third power transmission belts on a plane perpendicular to the axis of the crankshaft, and providing the first to third gears on a plane perpendicular to the axis of the crankshaft, the crank Elongation of the engine in the axial direction of the shaft can also be prevented. Moreover, the balancer shaft on the upper block 1 side of the tension side of the third power transmission belt can be minimized and the relative phase angle error between the crankshaft 7 and both balancer shafts 16 can be minimized. And a guide for the first power transmission belt and its support 28a between the balancer shaft 16a on the upper block 1 and the tension side of the third power transmission belt (chain 19). By providing the member 28a, the invalid space can be efficiently used.

Furthermore, in the above-described configuration of the present invention, for example, the balancer is connected by connecting the crankshaft 7 with one of the balancer shafts installed in a 4-cycle V-shaped 8-cylinder engine having a flat crank and having a bank having an angle of 90 degrees. A balancer shaft drive subchain 19 for driving one of the shafts 16 and a cam drive timing chain 15 for driving the cam for opening and closing the intake or exhaust valves face each other on their tensioning sides. It is preferable that the guide member 28 and the guide member 25 for each chain are integrated with each other.

Moreover, the cam drive timing chain 15 for driving the balancer shaft drive subchain 19 and the cam for opening and closing the intake or exhaust valves is arranged on the same plane perpendicular to the axis of the crankshaft 7. The guide member 28 and guide member 25 for each chain are integrated with each other, thereby reducing the number of guide members for the chain and sharing the support for the guide member. This prevents the guide member from growing in the axial direction of the crankshaft. Moreover, since there is no torsional load applied from the chain to the guide member, that is, the load applied from the chain is directed to occur only in the same plane, the durability of the guide member can be improved. Moreover, the integrated guide members 25, 28 are mounted on the shaft of the balancer shaft supported on the cylinder block on the balancer shaft drive subchain 19 at the end of the balancer shaft, whereby the guide member is the shaft of the balancer shaft. It can be installed by effectively using the space with respect to, and oil can be supplied to the subchain from the balancer shaft side through these guide members. The subchain can be used not only to drive the balancer device but also to drive oil pumps, water pumps and the like.

According to the above-mentioned preferable structure, it is possible to provide the V type internal combustion engine provided with the sub chain which can be made small and light in size.

Furthermore, in the above-described configuration according to the present invention, a pair of driven pinions 12a, 12b installed in each cylinder bank are simultaneously geared to the drive pinion 11 coupled to the crankshaft 7 so that the crankshaft Is transmitted to the camshaft for opening and closing the intake valve or the exhaust valve, and the pair of driven pinions are driven by the pinion of the pair of driven pinions in a state in which the gear engagement is half a pitch shift between the driven pinions. There is an advantage in that a cam drive structure is provided which is geared in engagement with the gear.

According to this configuration, since the phases in which the driven pinion engages the drive pinion with the driver pinion in both cylinder blocks are shifted by half pitch between each other, and the wavefront of the generated interlocking noise is shifted accordingly, the interlocking noise from each cylinder bank is reduced. The noise level when synthesized can be suppressed to a low level.

Furthermore, in the above-described configuration according to the present invention, a pair of driven pinions 12a, 12b installed in each cylinder bank are simultaneously geared to the drive pinion 11 coupled to the crankshaft 7 so that the crankshaft Rotational force is transmitted to the camshaft for opening and closing the intake valve or the exhaust valve, and the winding power transmission means interposed between the driven pinion and the camshaft includes the chain 15 and the sprockets 13 and 14 or the belt with teeth. The sprockets 13a, 13b or toothed pulleys, which include a pulley and are integrally provided in each of the pair of driven pinions, have sprockets or toothed pulleys with a chain or toothed belt. There is an advantage in that the cam drive structure is provided in which the sprockets 13a and 13b or the toothed pulley are installed to mesh with the chain 15 or the toothed belt while the wheel engagement is half pitched between each other. .

According to this configuration, the phase in which the sprocket or toothed pulley meshes with the chain or toothed belt in the two cylinder banks is shifted half a cycle, and the wavefront of the generated interlocking noise is shifted accordingly. The noise level when the interlocking noise is synthesized can be suppressed to a low level. Furthermore, the sprocket or toothed pulley is connected to the chain or toothed belt with the gear engagement in one of the banks of cylinders shifted half a pitch from the gear engagement in the other bank when the interlocking noise is high at the beginning of the gear engagement. Even if the gear is engaged, the noise level can be further reduced if this half pitch shifted gear engagement is placed towards its end.

Moreover, the present invention simultaneously engages a pair of driven pinions (12a, 12b) installed in each cylinder bank with a drive pinion (11) coupled to the crankshaft (7) so that the rotational force of the crankshaft is intake valve or The pair of driven pinions are transmitted to the camshaft pins, and the pair of driven pinions are transmitted to the camshaft 5 while the pair of driven pinions are shifted by half a pitch between the gear pinions of the actuator pinions. The pair of driven pinions are wheel-engaged and the wound power transmission means interposed between the driven pinions and the camshaft includes a chain 15 and sprockets 13 and 14 or a toothed belt and a toothed pulley. The sprockets 13a and 13b or the toothed pulleys integrally provided in each of the pair of driven pinions are provided with a chain or a toothed belt. Sprocket or toothed pulleys are installed such that the sprocket or toothed pulley is meshed with the chain or toothed belt with the gear meshing half-shifted from each other, and the angle of assembly marking for regulating the angle of assembly for each cylinder bank (47) ) Provides a four-cycle V-type engine cam drive structure mounted on the gear assembly 46 with sprockets or toothed pulleys integrally mounted on the driven pinion.

According to this configuration, since the gear engagement phases in both cylinder banks are shifted by half pitch between each other, and the wavefront of the generated interlocking noise is shifted accordingly, the noise level when the interlocking noise is synthesized from each cylinder bank is kept at a low level. It can be suppressed and misassembly can be avoided so that a certain gear engagement state can be surely realized. That is, even if it is possible to realize the engagement of the driven pinion with the above-described actuator pinion by assembling the respective gears on the swing shaft arranged to satisfy the predetermined condition, the positional relationship of the sprocket or toothed pulley is If the driven pinions provided integrally are influenced by the assembling angles when assembled, and if they are assembled incorrectly, the above-mentioned predetermined gear engagement state cannot be realized. In order to cope with this, as described above, by assembling the assembly angle mark on the gear assembly for each cylinder bank, erroneous assembly can be avoided. In addition, the gear assembly can be shared between each cylinder bank, which has the advantage of keeping many types of component increase at a low level.

According to this configuration, it is possible to provide a cam drive structure configured to eliminate the risk of generating a high level of noise, respectively, from a reduction mechanism provided independently of a pair of cylinder banks of a 4-cycle V-shaped engine.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an elevational view of the crank pulley side of a four cycle V-shaped 8 cylinder engine applied to the present invention.

The engine (E) has an upper block (1) provided with a pair of cylinder banks having an inclination angle of 90 degrees, a lower block (2) coupled to a lower side of the upper block (1), and a lower side of the lower block (2). It includes an oil pan (3) coupled to the cylinder head (4a, 4b) respectively coupled to the upper side of both cylinder banks of the upper block (1). Moreover, two camshafts 5a and 5b are provided on each cylinder. These camshafts 5a and 5b are covered with head covers 6a and 6b respectively coupled to the upper sides of the cylinder heads 4a and 4b.

The crankshaft 7 is supported on the mating surface between the upper block 1 and the lower block 2 by a main bearing, as in a known engine.

An air conditioner compressor 8 is mounted on the upper block 1 on the right side of the crankshaft 7, and an alternator 9 is mounted on the lower block 2 on the left side of the crankshaft 7. do. These compressors 8 and generators 9 are connected to the crankshaft through a belt / pulley mechanism not shown in the drawings.

The crank sprocket 10 is inserted and fixed on the crankshaft 7 at a position inside the axis of the crank pulley, and the driver pinion 11 is at a position inside the axis of the crank sprocket 10 at the crankshaft 7. Insertion is fixed.

The two deceleration driven pinions 12a, 12b are simultaneously engaged with the cog wheels of the driver pinion 11, each of which is a plane that divides the banks that form an angle and penetrates the center of the crankshaft. It acts as first and second gears which are installed at positions which are laterally symmetrical. The small sprockets 13a and 13b are integrally mounted on the driven pinions 12a and 12b and each of the silent chains 15a and 15b serving as the first and second endless power transmission belts are each of these small sprockets. (13a, 13b) and cam sprockets (14a, 14b), each of the cam sprockets (14a, 14b) are two camshafts (5a, 5b) of each of the cylinder banks to drive the camshaft It is installed to be wound on. By doing so, the rotational force generated by the crankshaft 7 can be transmitted to the two camshafts 5a and 5b of both cylinder banks.

The upper block 1 and the lower block 2 are separated from each other in a horizontal plane passing through the center of the crankshaft 7, and two balancer shafts 16a and 16b having axes extending parallel to the crankshaft 7 are provided. It is rotatably supported at a position perpendicular to the separation plane.

The balancer shaft sprocket 17 is inserted and fixed on the balancer shaft 16b of the two balancer shafts 16a and 16b, and one end of this balancer shaft 16b is supported by the lower block side. The silent chain 19 acting as a third endless power transmission belt is mounted on the lower side of the balancer shaft sprocket 17, the crank sprocket 10, the lower block 2 to drive the balancer shaft. The pump balancer 18 fixed to an oil pump (not shown) is wound around them, whereby the lower balancer shaft 16b and the oil pump are configured to rotate in conjunction with the crankshaft 7.

The two balancer shafts are adapted to rotate in opposite directions at the same rotational speed through the gear meshing of the gears 20a and 20b acting as third gears, the gears 20a and 20b being the balancer shaft sprawlers. It is fixed on the balancer shaft inwardly on the axis of the kit 17 and has the same number of gear teeth, respectively.

The balancer shaft 16 is provided on the tension side of the silent chain 19 with respect to the rotational direction of the crankshaft 7. This makes it possible to minimize the relative phase angle error between the crankshaft 7 and the balancer shaft 16.

Here, each camshaft drive silence chain 15a, 15b is configured as described above to be driven by the crankshaft 7 (driver pinion 11) via the deceleration driven pinion 12a, 12b. Slightly spaced apart from the crankshaft 7, the silent chain 19 is wound around the balancer shaft 16b (balancer shaft sprocket 17) supported on the lower block side, so that the first endless power belt There is no risk that the silent chain 15a acting as an interlock with the silent chain 19 acting as a third infinite power transmission belt. As a result, it is possible to prevent the engine E from being elongated, especially in the axial direction of the crankshaft 7. In this configuration, the silent chains 15a and 15b and the silent chains 19 are arranged on a plane crossing at right angles to the axis of the crankshaft 7, and the driven pinions 12a and 12b and the gears 20a and 20b. ) Is arranged on a plane crossing at right angles to the axis of the crankshaft 7, so that the engine E can also be prevented from elongating in the axial direction of the crankshaft 7.

The chain tensioners 22 to 24 and the anti-runout chain guides 25 to 28, in which the pressing force is automatically adjusted by the hydraulic plunger, are connected to the cam sprockets 14a and 14b of each camshaft 5 of both cylinder banks. It is attached to the silent chains 15a and 15b which are wound and the silent chain 19 which is wound around the balancer shaft sprocket 17 and the pump sprocket 18, respectively. These chain tensioners 22 to 24 and the chain guides 25 to 28 are respectively bolted to the end face of the upper block 1, the lower block 2, the oil pan 3 and the cylinder head 4a on the crank pulley side. , 4b) respectively.

Here, the chain guide 28 and the support part 28a on the tension side of the silent chain 19 are provided between the tensioner side of the silent chain 19 and the balancer shaft 16a on the upper block side. This makes it possible to easily and effectively use the void space formed between the tensioner side of the silent chain 19 and the balancer shaft 16a on the upper block side, thus eliminating the need to enlarge the chain guide 28 unnecessarily.

Moreover, this chain guide 28 is integrated with the chain guide 25 for the silent chain 15a disposed on the side where the balancer shaft 16 is installed. This makes it possible to share at least two necessary supports, thereby reducing the number of components and the involved component assembly time. Moreover, these integrated chain guides 25 and 28 are configured to cover the balancer shaft 16a on the upper block side on which they are located, but their position in the axial direction of the crankshaft and the end of the balancer shaft 16a. Because of the coincidence, these chain guides can be arranged by effectively utilizing the space outside the end of the balancer shaft, and these chain guides can also be used as thrust bearings for the balancer shaft 16a. In this case, the need to add a thrust bearing element, such as a thrust plate, can be eliminated and this also serves to reduce the component count and increase in engine size.

As shown in FIG. 3 showing other main parts, the tensioning side of the timing chain 15 and the tensioning side of the silent chain 19 are disposed closely to each other. Due to this, the integrated chain guides 25 and 28 become small. The term "direct surface" as used herein means that the angle involved between the tension side of the timing chain 15 and the tension side of the silent chain 19 is less than 90 degrees.

Moreover, these integrated chain guides 25 and 28 are configured to cover the balancer shaft 16a disposed on the upper block side, but their positions coincide with the ends of the balancer shaft 16a in the axial direction of the crankshaft. Therefore, these chain guides can be used as thrust bearings for the balancer shaft 16a. In this case, the thrust plate may be omitted, and oil flowing out of the balancer shaft 16a may be supplied to the silent chain 19 through the integrated chain guides 25 and 28.

On the other hand, the chain guide 27 is configured to cover the upper surface of the pump sprocket 18. This prevents oil from being unnecessarily mixed up and spread by the pump sprockets 18 and the silent chain 19.

Thus, according to the present embodiment, a balancer shaft drive subchain for driving one of the balancer shafts installed in a 4-cycle V-shaped 8-cylinder engine, for example, employing a flat crank and having a bank having an angle of 90 degrees, and an intake valve Or a cam drive timing chain for driving a cam for opening and closing the exhaust valve faces each other on its tensioning sides, and their guide members are integrated with each other. This can reduce the number of components by reducing the number of guide members required for the chain, whereby the engine can be minimized. In addition, the support for the guide member can be shared, and the time required for component assembly can be reduced. Moreover, because the tensioning sides of each chain face each other, the guide member can also be minimized. Moreover, the balancer shaft drive subchain and the cam drive timing chain are arranged on the same plane perpendicular to the axis of the crankshaft so that the guide members for each chain are integrated with each other, thereby reducing the number of guide members for the chain. As described above, it is possible to reduce, not only to share the support for the guide member, but also to prevent the guide member from growing in the axial direction of the crankshaft. Also, since there is no torsional load applied from the chain to the guide member, that is, the load applied from the chain is directed to occur only in the same plane, the durability of the guide member can be improved. Moreover, the integrated guide member is installed on the shaft of the balancer shaft supported on the cylinder block on the balancer shaft drive subchain 19 at the end of the balancer shaft, whereby the guide member effectively spaces about the axis of the balancer shaft. It can be installed by use, and oil can be supplied to the subchain from the balancer shaft side through these guide members, which simplifies its structure.

As shown in detail in FIG. 4, the left and right driven pinions 12a, 12b are geared to the driver pinion 11 such that they are half pitch shifted in each cylinder bank with gear engagement with the driver pinion. The engagement of the left and right driven pinions 12a, 12b with the drive pinion 11 in such a half-pitch shift means that the gears of these driven pinions and the drive pinion are along a straight line a, b connecting the centers of the respective gears. It is obvious when comparing the engagement parts.

This gear engagement state can be realized by setting the relative mounting angles α (degrees) for mounting the driven pinions 12a and 12b to the driver pinion 11 as follows.

α = (n + 1/2) β

Where n is any integer. β is the same center angle as the tooth pitch of the driver pinion 11, and when the number of teeth of the driver pinion 11 is Z1, the center angle is obtained from the following equation.

β = 360 / Z1

In FIG. 4, the number Z1 of the driver pinions 11 is 36, the center angle β is 10 degrees, and the mounting angle α is 85 degrees (n = 8).

The gear assembly 46 in which the driven pinions 12a and 12b and the small sprockets 13a and 13b are integrally used is equally used on the left and right sides, and an assembly angle mark is engraved in the end face of the gear assembly. The letter R or L is attached to the assembly angle mark 47, and the assembly angle mark 47 with the R subscript is attached to the gear assembly 46 disposed on the right side when viewed from the driver's seat (left assembly in FIG. 4). And the assembly angle indicator 47 is placed at the point where the driven pinion 12 engages the gear pinion, and the gear assembly disposed on the left side when viewed from the driver's seat (assembly on the right side in FIG. 4). 46, the L-shaped assembly angle display 47 is attached, and the assembly angle display 47 is placed at the point where the drive pinion 12 meshes with the drive pinion.

Therefore, the left and right small sprockets 13a and 13b are silent in the above-described configuration such that the left and right driven pinions 12a and 12b are engaged with the drive pinion so that the gear engagement is half pitch shifted in each cylinder bank. The phases of the driven pinions 12a, 12b and the phases of the small sprockets 13a, 13b are set so as to realize the gear engagement state which is half pitch shifted with respect to the chain 15, and the assembling angle display 47 is Attached to the gear assembly in each cylinder bank, the gear assembly 46 can be used in common for each cylinder bank, and an increase in the number of components can be suppressed. Noise levels can be suppressed to significantly lower levels. This half pitch shifted gear engagement is evident when comparing the gear engagement portions on radial straight lines c, d that intersect the centerlines on the side pulling the silent chain 15 shown in FIG. Furthermore, in FIG. 4, the number Z2 of driven pinions 12 is set to 45 and the number Z3 of small sprockets 13 is set to 25, thereby making the same position every 72 degrees. By setting the relative positional relationship between the two gears to be taken, it is possible to attach five assembly angle marks 47 to each gear assembly 46.

As described so far, according to the above embodiment, the phase of the gear engagement of the gear is shifted half a foot in both cylinder banks, and thus the wavefront of the gear engagement is shifted accordingly, so that when the interlocking noise is synthesized. The noise level can be suppressed to low levels. Therefore, this embodiment has an advantage in reducing noise from the engine.

Moreover, in the above configuration, the chain is used as an endless power transmission belt, but a belt may be used instead. In this case, the sprocket used by the above-mentioned structure can also be replaced by a pulley.

Moreover, although the subchain is used to drive the balancer device and the oil pump in the above-described operating mode, the application of the subchain is not limited to this and can also be used to drive the water pump and the like.

Although described in connection with a preferred embodiment of the present invention, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the present invention and, therefore, fall within the true spirit and scope of the present invention. All such changes and modifications are intended to be included in the appended claims.

Thus, according to the present invention, there is provided a balancer device for a V-type engine which is provided with a flat crank having a bank whose centers of all crank pins are in the same plane and form a 90 degree angle, wherein the first and second gears 12 are provided. Each is interposed between the first and second endless power transmission belts driving the camshaft and the crankshaft 7, respectively, on the cylinder head of each of the V-shaped cylinder banks, and the shafts of the pair of balancer shafts 16a, 16b. The upper block 1 and the lower block 1 of the cylinder block from a horizontal plane passing through the center of the crankshaft 7 so that they are parallel to the crankshaft 7 so that the balancer shafts 16a, 16b are rotated in opposite directions. The pair of balancer shafts 16a and 16b are installed at positions symmetrical with respect to the separation plane acting as a center where 2) is spaced apart from each other, and the balancer shaft on the crankshaft 7 and the lower block 2 is installed. 16b are connected to each other by a second endless power transmission belt, and the balancer shaft 16b on the lower block 2 side and the balancer shaft 16a on the upper block side are mutually connected by the third gears 20a and 20b. By being connected, the pair of balancer shafts 16a, 16b are driven to rotate in directions opposite to each other. According to this configuration, the first and second endless power transmission belts for driving the balancer shaft are prevented from overlapping each other in the axial direction of the crankshaft, thereby preventing the extension of the engine in the axial direction of the crankshaft. The complicated layout of the third endless power transmission belt can also be eliminated. In particular, by arranging the first to third power transmission belts on a plane perpendicular to the axis of the crankshaft, and installing the first to third gears on a plane perpendicular to the axis of the crankshaft, the crank Elongation of the engine in the axial direction of the shaft can also be prevented. Moreover, the balancer shaft on the upper block 1 side of the tension side of the third power transmission belt can be minimized and the relative phase angle error between the crankshaft 7 and both balancer shafts 16 can be minimized. And a guide member 28a for the first power transmission vent and the support 28a therebetween between the balancer shaft 16a on the upper block 1 and the tension side of the third power transmission belt. This makes it possible to efficiently use the invalid space.

Claims (11)

In a V-type internal combustion engine having a balancer device, Crankshafts; A V-shaped cylinder bank having a bank forming an angle of 90 degrees; A first endless force transmission belt for driving a first camshaft member installed on the cylinder head of one of the V-shaped cylinder banks; A first gear interposed between the first endless power transmission belt and the crankshaft; A second endless power transmission belt for driving a second camshaft member installed on a cylinder head of another bank of the V-shaped cylinder banks; A second gear interposed between the second endless power transmission belt and the crankshaft; A pair of balancer shafts that rotate in opposite directions and extend in parallel to the crankshaft; A pair of third gears driving each of the pair of balancer shafts; And A third power transmission belt connecting one of the crankshaft and the balancer shaft, the third power transmission belt being disposed at a position outside the area in contact with the first and second endless power transmission belts on a plane perpendicular to the axial direction of the crankshaft; V-type internal combustion engine comprising a. The crankshaft of claim 1, wherein the crankshaft comprises a planar crank in which the axial centers of all crankpins of the cylinders concerned lie in a common plane, The V-shaped cylinder bank includes a cylinder block spaced apart from each other the upper block and the lower block with respect to the horizontal plane passing through the center of the crankshaft, One of the balancer shaft pairs disposed on the lower block side is connected to the crankshaft through the third endless power transmission belt, The other shaft of the pair of balance shafts disposed on the upper block side is connected to the one of the pair of balance shafts by being meshed with the third gear pair so that the balance shaft pairs rotate in opposite directions. V-type internal combustion engine. According to claim 1 or 2, wherein the first to third power transmission belt is disposed in a first plane that crosses at right angles to the axis of the crankshaft, And the first to third gears are disposed on a second plane crossing at right angles to the axis of the crankshaft. The shaft according to claim 1 or 2, wherein one of the balance shafts disposed on the upper block side is disposed on the tension side of the third power transmission belt, The engine further comprises a guide member for guiding the third power transmission belt and supported by a support disposed between the balancer shaft on the upper block side and the tension side of the third power transmission belt. Type internal combustion engine. The said power side of the said 3rd power transmission belt faces the tension side of the said 1st power transmission belt, The said guide member is the said 1st power transmission belt and the said 3rd power transmission belt. And guide members are disposed on the tension side of the first power transmission belt and on the tension side of a third power transmission belt. The guide of claim 1 or 2, wherein the tension side of the third power transmission belt and the tension side of the first power transmission belt are disposed in a third plane perpendicular to the axis of the crankshaft, and the guide The member guides both the first power transmission belt and the third power transmission belt, and the guide member is disposed on the tension side of the first power transmission belt and also on the tension side of the third power transmission belt. V-type internal combustion engine. 6. The V-shaped internal combustion engine as claimed in claim 5, wherein the guide member is installed at a position intersecting an axis of one of the pair of balancer shafts disposed on the third power transmission belt. 8. The V-type internal combustion engine according to claim 7, wherein the guide member receives a thrust force of one of the balancer shafts. 2. The crankshaft of claim 1, wherein the crankshaft is coupled to a drive pinion geared to both the first and second gears such that the first and second gears have a half-pitch shift of the gear engagement to the drive pinion. The V type internal combustion engine characterized by the above-mentioned. 10. The method of claim 9, wherein each of the first and second gears comprises one of a scribing and toothed pulley, each of the first and second power transmission belts comprising one of a chain and a toothed belt, One of the sprocket and the toothed pulley is one of the chain and the toothed belt such that one of the sprocket and the toothed pulley is shifted half a pitch between the gear engagement with one of the chain and the toothed belt. Gears mesh with one, The assembly angle indication for regulating the assembly angle for each cylinder bank is characterized in that one of the sprocket and the toothed pulley is provided on a gear assembly which is integrally installed with one of the first and second gears. V-type internal combustion engine. The crankshaft of claim 1, wherein the crankshaft is connected to a driver pinion that is in gear engagement with the first and second gears. Each of the first and second gears comprises one of a sprocket and a toothed pulley, Each of the first and second power transmission belts includes one of a chain and a toothed belt, One of the sprocket and the toothed pulley is one of the chain and the toothed belt such that one of the sprocket and the toothed pulley is shifted half a pitch between the gear engagement with one of the chain and the toothed belt. V-shaped internal combustion engine, characterized in that the gear meshed with one.

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