JPH03260303A - V-type engine camshaft drive mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a camshaft drive mechanism for a V-type engine, and in particular, it is possible to reduce the diameter of each side cam gear without reducing the diameter of the crank gear, and also to avoid unnecessarily large diameters. This invention relates to a camshaft drive mechanism for a ■-type engine that can be configured without causing

[Conventional technology]

Engines that are internal combustion engines include in-line, opposed, and V-type engines, depending on the arrangement of cylinders. An example of a V-type engine in which cylinder banks on each side are arranged in a 7-shape is shown in FIG. In the figure, 102 is a V-type engine, 104-1 is one cylinder bank, and 10
4-2 is the other side cylinder bank. V type engine 10
2, a negative side bank cylinder 10B-1 and an other side bank cylinder 108 are respectively attached to the 7-shaped cylinder block 106.
-2 and each side bank cylinder 10B
Radar 11 to the - side cylinder at the top of -1 and 108-2 respectively.
The cylinder banks 104-1 and 104-2 are arranged in a V-shape.

A bearing cap 112 is attached to the lower part of the cylinder block 106, and one crankshaft 114 is pivotally supported by the cylinder block 106. Note that an oil pan 116 is attached to the lower part of the bearing cap 112.

Each of the side bank cylinders 10B-1 and 108-2 includes:
Pistons 11B-1 and 118-2 are provided, respectively, and are connected to the one crankshaft 114 by connecting glands 120- and 120-2 on each side.

The cylinder heads 110-1 and 110-2 on each side include
Each side intake port 122-1, 122-2 and each side exhaust boat 124-1, 124-2 are provided, which communicate with each bank cylinder 10B-1, 108-2, respectively, and each side intake port 122-1, 124-2 is provided. 122-2 and each side intake valve 126-1/l which opens and closes each side exhaust boat 124-1/124-2, respectively 26-2 and each side exhaust valve 128-
1.128-2 is provided. Each side intake port 12
2-1 and 122-2 are cylinder banks 104-1 on each side.
- Provided on the side approaching the space 130 between 104-2,
An intake device (not shown) disposed in this space 130 is communicated with the space 130 . In addition, each side exhaust boat 124-1, 124
-2 is provided on the side away from the space 130 and communicates with an exhaust device (not shown).

Each side cylinder head 110-1, 1102 includes each side intake valve 126-1, 126-2 and each side exhaust valve 128.
-1/128-2 Each tilting valve mechanism 132- opens and closes
1.132-2 is provided. Each tilting valve mechanism 132-1
・132-2 is the cylinder head 11 (1-1, 1
One camshaft 134-1 on each side is pivotally supported by 10-2.
・134-2 and pivots on each side 136-1 and 136-2
The intake valves 126-1 and 126-2 on each side are swung around the fulcrum.
Swing type Rofka arm on each side that opens and closes 138-1
・13B-2 and each rocker shaft 140-1 and 14
The exhaust valves 128-1 and 12 on each side are swung around 0-2 as a fulcrum.
Two rocker arms 142 on each side that drive opening and closing of 8-2
-1・142-2. Therefore, each of the retracting valve mechanisms 132-1 and 132-2 has a single camshaft 134-1 and 134-2 on each side, respectively, to each side intake air of seven doors 110-1 and 110-2 to each side cylinder. Valve 126-1
・It opens and closes 126-2 and each side exhaust valve 128-1, 128-2, and each side cylinder bank 104-
They are arranged symmetrically across the space 130 between 1 and 104-2. Further, each side cylinder head 110-1
・In 110-2, each tilting valve mechanism 132-1, 132-
Each side head cover 144-1, 144-2 covers 2.
has been established.

In such a type engine 102, normally each side camshaft 134- of each tilting valve mechanism 132-1, 132-2 is
1/134-2 is driven by a timing belt and chino. In this case, each tilting valve mechanism 132-1, 13
The respective side camshafts 134-1 and 134-2 of 2-2 are rotationally driven in the same direction as the crankshaft 114 (for example, in the direction of arrow A).

Alternatively, as disclosed in Utility Model Application Publication No. 56-4605,
There is a V-type engine in which each side camshaft of each tilting valve mechanism is driven by a gear train. The camshaft drive mechanism disclosed in this publication has an intermediate gear train and a reduction gear train on each side that mesh the cam gears on each side with the crank gear, respectively, which are arranged symmetrically with respect to the cylinder banks on each side of the type engine. The side camshaft is driven to rotate in the same direction as the crankshaft.

However, when each of the camshafts 134-1 and 134-2 is rotated in the same direction as the crankshaft 114 (for example, in the direction of arrow A), as shown in FIG.
An example of the cam surface 146 of one side cam shaft 134-1 pivotally supported by
-1 is an example of the seesaw two rocker arm 142-1 that drives the - side exhaust valve 12B-1 to open and close the slipper surface 148-
1 from the distal end side toward the fulcrum side, buckling deformation occurs on the negative side slipper surface 148-1, making it difficult to obtain an accurate valve lift amount.

Therefore, as shown in FIG. 4, a crank gear 150 is provided on the crankshaft 114 supported by the cylinder block 106, and each side cylinder bank 104-1, 104-
Each side cam gear 152-1, 152-2 is provided on each side camshaft 134-1, 134-2 which is rotatably supported by each side cylinder head 110-1, 110-2 of 2, and each side camshaft 13
The respective side cam gears 152-1 and 134-2 are connected to the crank gear 150 in order to rotate the cam gears 152-1 and 134-2 in opposite directions.
152-2 to intermediate gear trains 154-1 and 154- on each side, respectively.
There is a camshaft drive mechanism that is provided in mesh with each other through two.

According to such a camshaft drive mechanism, each side camshaft 134
-1 and 134-2 in opposite directions (arrow A direction and arrow B direction), for example, as shown in FIG. The m cam surfaces 146-1 of the m camshafts 134-1 that are rotationally driven rotate the slipper surface 148-1, an example of the seesaw rocker arm 142-1, which drives the opening and closing of the exhaust valve 128-1, from the fulcrum side. This allows the slipper surface 14B-1 to cross over toward the tip end, thereby making it possible to obtain an accurate valve lift amount without causing buckling deformation on the slipper surface 14B-1.

[Problem that the invention seeks to solve]

However, the side cam gears 152-1 and 152-2 of each side camshaft 134-1 and 134-2 are driven to rotate at 1/2 the rotation speed of the crank gear 150 of the crankshaft 114. Therefore, each side cam gear 152-
There is a problem that the diameter of 1.152-2 becomes large. For this reason, each side head cover 144-1, 144-2 that covers each tilting valve mechanism 132-1, 132-2 of each side cylinder head 110-1, 110-2 must be enlarged, As a result, as shown in FIG. 4, the area around the cylinder head becomes larger, and the distance H from the lower end of the cylinder block 106 to the upper end of each side hend force bar 144-1, 144-2 increases, resulting in an increase in engine height. This leads to an increase in the number of particles, which is disadvantageous in terms of installation in a vehicle.

In order to eliminate this inconvenience, each side cam gear 152-
When the diameter of 1.152-2 is reduced, the crank gear 15
The diameter of 0 will be reduced at a rate twice that. For this reason, the number of engagements of the teeth increases, which causes damage to the tooth surfaces and shortens the service life. Furthermore, when the diameter of the crank gear 150 is reduced, as shown in FIG.
This makes it difficult to form the crank gear 150 separately from the crankshaft 114 and mount it on the crankshaft 114, and the crank gear 150 must be integrally machined with the crankshaft 114. Therefore, there is an inconvenience that gear cutting becomes difficult, and if the crank gear 150 is damaged, it must be replaced together with the crankshaft 114.
This has the disadvantage of reducing maintainability.

In addition, the camshaft drive mechanism using the gear train disclosed in the above-mentioned publication has an intermediate gear train and a reduction gear train on each side that mesh the cam gears on each side with the crank gear, respectively, symmetrically with respect to the cylinder banks on each side of the V-type engine. Since the camshaft drive mechanism is disposed in the camshaft, there is an inconvenience that the camshaft drive mechanism becomes unnecessarily large.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to reduce the diameter of each side cam gear without reducing the diameter of the crank gear, and to reduce the size of the cylinder head surrounding area of a V-type engine without increasing the size unnecessarily. This reduces the height of the engine, which is advantageous when mounted on a vehicle, reduces damage to the crank gear and extends its life, and facilitates gear cutting of the crank gear. The object of the present invention is to realize a camshaft drive mechanism for a ■-type engine that can improve maintainability.

[Means for solving problems]

In order to achieve this object, the present invention provides a crank gear on a crankshaft pivotally supported by a cylinder block of a V-type engine, and each side of each cylinder bank of the V-type engine is pivotally supported by a cylinder head on each side. A type engine in which a camshaft is provided with a cam gear on each side, and the cam gear on each side is meshed with the crank gear via an intermediate gear train on each side to drive the camshaft on each side to rotate in opposite directions. In the camshaft drive mechanism, a reduction gear train is provided which meshes with the crank gear and the intermediate gear trains on each side to reduce and transmit driving force, and the reduction gear train is connected to the crank gear and the intermediate gear trains on each side. It is characterized by being biased toward one of the banks.

[Effect]

According to the configuration of the present invention, there is provided a reduction gear train that meshes with the crank gear and the intermediate gear trains on each side to reduce and transmit the driving force, and also connects this reduction gear train to the crank gear and the intermediate gear train on each side. By arranging the cam gears biased to one side, it is possible to reduce the diameter of the cam gears on each side without reducing the diameter of the crank gear due to deceleration of the driving force by the reduction gear train. It is possible to construct a camshaft drive mechanism that can reduce the driving force by the reduction gear train without any problems.

〔Example〕

Next, embodiments of the present invention will be described in detail based on the drawings.

1 and 2 show an embodiment of the invention. In FIG. 1, 2 is a type engine, 4-1 is a cylinder bank on one side, and 4-2 is a cylinder bank on the other side. ■ Type engine 2 is at the top of the character -shaped cylinder block 6 -Example cylinder head 8-1 and other side cylinders.
Equipped with -2, each cylinder bank 4-1 and 4-2 ■
arranged in a letter shape.

A bearing cap 10 is attached to the lower part of the cylinder block 6, and one crankshaft 12 is pivotally supported by the cylinder block 6. In addition, bearing cap 10
An oil pan 14 is assembled at the bottom of the.

The respective side cylinder heads 8-1 and 8-2 are provided with respective tilting valve mechanisms 16-1 and 16-2 for opening and closing respective side intake valves and respective side exhaust valves (not shown). Each of the tilting valve mechanisms 16-1 and 16-2 is connected to a cylinder on each side by rads 8-1 and 8.
One camshaft 18-1 and 18 on each side, each pivotally supported by -2.
-2 opens and closes each side intake valve and each side exhaust valve (not shown) of each side cylinder head 8-1 and 8-2 via a swing type rocker arm and a seesaw type rocker arm, and each side cylinder bank 4- They are arranged symmetrically across the space 20 between 1 and 4-2. In addition, each tilting valve mechanism 16-1 and 8-2 to each side cylinder are
1. Each side head cover 22-1, 2 that covers Yellow 2
2-2 is provided.

In this V-type engine 2, a crank gear 24 is provided on a crankshaft 12 which is rotatably supported by a cylinder block 6, and is rotatably supported by cylinder heads 8-1 and 8-2 on each side of cylinder punctures 4-1 and 42, respectively. Each side cam shaft 18-1, 18
-2 is provided with respective side cam gears 26-1 and 26-2, and each side cam gear 26-1 is provided on the crank gear 24 in order to drive the respective side cam shafts 18-1 and 18-2 to rotate in mutually opposite directions.・
26-2 are provided in mesh with each other through respective intermediate gear trains 28-1 and 28-2.

In such a camshaft drive mechanism of the V-type engine 2,
Crank gear 24 and intermediate gear trains 28-1 and 28-2 on each side
a reduction gear train 30 that is meshed with the
, and the reduction gear train 30 is arranged so as to be biased toward either side of the cylinder banks 4-1 and 4-2 with respect to the crank gear 24.

To be more specific, in this embodiment, the one-side intermediate gear train 2B-1 of the respective side intermediate gear trains 28-1 and 28-2 is composed of one one-side first intermediate gear 2B-1a. . The intermediate gear train 28 on the other side of each side intermediate gear train 28-1, 28-2
-2 is the other side first intermediate gear 28- in this embodiment.
2a and the other second intermediate gear 28-2b.

The reduction gear train 30 includes two reduction gears, a large-diameter first reduction gear 30a and a small-diameter second reduction gear 30b.
2 are aligned with each other, and the axis 32 is biased toward one of the cylinder banks 4-1 and 4-2, for example, toward the cylinder bank 4-1. In this case, in the V-type engine 2, for example, the axial direction end surface 34-1 of the other cylinder bank 4-2 is compared to the axial end surface 34-1 of the cylinder bank 4-1.
2 will be installed protrudingly. Therefore, a reduction gear train is provided on the axial direction side end surface 34-1 of the one side cylinder bank 4-1, which is located on the axially inner back side with respect to the axial direction side end surface 34-2 of the other side cylinder bank 4-2. 30, the reduction gear train 30 can be arranged without unnecessary protrusion. Moreover, by reducing the driving force by this reduction gear train 30, the diameter of the crank gear 24 can be increased without reducing the diameter thereof, and the cam gears 26-1 and 26-2 on each side are provided with reduced diameters.

These gears mesh as shown below.

The crank gear 24 includes, for example, a cylinder bank 4-1.
The large-diameter first reduction gear 30a of the reduction gear train 30, which is arranged biased to the side, is provided in mesh with the first reduction gear 30a.

The small-diameter second reduction gear 30b of the reduction gear train 30 includes, for example, an intermediate gear train 2 disposed on the cylinder bank 4-1 side.
An example of 8-1 is provided in mesh with the first intermediate gear 2B-1a.
-1 side cam gear 26-1 meshingly provided.

The small diameter second reduction gear 30b of the reduction gear train 30 includes:
Further, the other side first intermediate gear 2B-2a of the other side intermediate gear train 28-2 disposed on the other side cylinder bank 4-2 side is provided in mesh with the other side first intermediate gear 2B-1a. The other side second intermediate gear 28-2b is provided in mesh with the other side second intermediate gear 2B-2b, and the other side second intermediate gear 2B-2b is provided in mesh with the other side cam gears 26-2 of the other side camshaft 18-2.

As a result, when the crank gear 24 is rotated, for example, in the direction of the arrow, the driving force that is decelerated and transmitted by the reduction gear train 30 is transmitted to the one-side cam gear 26- through the negative intermediate gear train 28-1. 1 in the direction of arrow B, and the other side cam gear 26-2 is rotated in the direction of arrow A via the other side intermediate gear train 28-2.

Therefore, each side camshaft 18-1 and 18-2 can be rotationally driven in mutually opposite directions (arrow A direction and arrow B direction). As a result, for example, each side cylinder bank 4-
Each tilting valve mechanism 16-1 is located across the space 20 between 1 and 4-2.
・One camshaft 18 on each side, in which the camshafts 16-2 are arranged symmetrically and are supported by the cylinder heads 8-1 and 8-2 on each side, respectively.
-1. Each side cylinder head a-i-B by 18-2
- When opening and closing each side intake valve and each side exhaust valve (not shown) in 2 through the swing type port 7 arm and the seesaw type rocker arm, the slipper surface of the seesaw type rocker arm can be prevented from buckling deformation. Therefore, it is possible to obtain an accurate valve lift amount.

In addition, the crank gear 24 and intermediate gear trains 28-1 and 28-2 on each side
A reduction gear train 30 is provided which meshes with the cylinder bank 8-2 and transmits the driving force at a reduced speed.
Since the crank gear 2 is biased toward one side of the cylinder bank 4-1 in this embodiment, the driving force of the reduction gear train 30 is decelerated.
The diameter of the cylinder bank 4-2 can be increased without reducing the diameter of the cylinder bank 4-2, and the diameter of the cam gears 26-1 and 26-2 on each side can be reduced.
A reduction gear train 3 is disposed on the axially side end surface 34-1 of the one side cylinder bank 4-1, which is located on the inner back side in the axial direction with respect to the cylinder bank 4-1.
By arranging 0, the reduction gear train 30 can be arranged without needlessly protruding, and a camshaft drive mechanism is constructed in which the driving force can be reduced by the reduction gear train 30 without unnecessarily increasing the size. be able to.

For this reason, the head covers 22-1 and 22-2 on each side, which enclose the tilting valve mechanisms 16-1 and 16-2 of the cylinders 4-1 and 4-2 on each side, can be made smaller. The area around the cylinder head can be made smaller, the distance H' from the lower end of the cylinder block 6 to the upper end of each side hand force par 22-1, 22-2 can be made small, and the height of the engine can be reduced. This can be advantageous in mounting.

Furthermore, since the crank gear 24 can be made larger in diameter instead of being made smaller, the number of teeth can be increased. For this reason,
The number of teeth meshing can be reduced, damage to the tooth surface can be reduced, and the service life can be extended.

Furthermore, since the crank gear 24 can be made larger in diameter instead of being made smaller in diameter, the crank gear 24 can be formed separately from the crankshaft, so as shown in FIG. It is possible to fit and mount the crank gear 24 on the shaft using the spline 36, and there is no need to integrally process the crank gear 24 with the crank shaft. Therefore, the gear cutting process can be facilitated and costs can be reduced, and if the crank gear 24 is damaged, only the crank gear 24 needs to be replaced, making it possible to improve maintainability.

〔Effect of the invention〕

As described above, according to the present invention, the diameter of the crank gear can be increased without reducing the diameter of the crank gear by reducing the driving force by the reduction gear train, and the diameter of each side cam gear can be reduced, and the diameter of the crank gear can be reduced, and the diameter of the cam gear on each side can be reduced, and the diameter of the crank gear can be reduced unnecessarily. It is possible to configure a camshaft drive mechanism that can reduce the driving force by the reduction gear train without causing damage.

For this reason, it is possible to downsize each side hemlock that encloses each tilting valve mechanism of each side cylinder head, and the area around the cylinder head can be downsized and the height of the engine can be reduced, which is advantageous when mounted on a vehicle. can do. Furthermore, since the crank gear can be made larger in diameter instead of being made smaller, the number of times the teeth engage can be reduced, damage to tooth surfaces can be reduced, and the life of the crank gear can be extended. Furthermore, since the diameter of the crank gear can be increased instead of being reduced in diameter, the crank gear can be formed separately from the crankshaft, and this separately formed crank gear can be mounted on the crankshaft. , there is no need to integrally process the crank gear with the crankshaft. Therefore, the gear cutting process can be facilitated and costs can be reduced, and if the crank gear is damaged, only the crank gear needs to be replaced, which improves maintainability.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the present invention, with Figure 1 being a front view of the camshaft drive mechanism of a ■-type engine, and Figure 2 being a half-sectional view of a crank gear formed separately from the crankshaft. . 3 and 4 show a conventional example, FIG. 3 is a half sectional view of a crank gear provided integrally with a crankshaft, and FIG. 4 is a front view of a camshaft drive mechanism of a V-type engine. 5 and 6 show a ■-type engine, FIG. 5 is an enlarged sectional view of a one-side valve operating mechanism provided in the cylinder head of an example of the ■-type engine, and FIG. 6 is a cross-sectional view of the ■-type engine. In the figure, 2 is a type engine, 4-1 is an example of a cylinder bank, 4-2 is an example of a cylinder bank on the other side, 6 is a cylinder block, 8-1 is an example of a cylinder head, 8-2 is an example of a cylinder head on the other side, and 12 is an example of a cylinder bank. Crankshaft, 16-1 is a valve mechanism on one side, 16-2 is a valve mechanism on the other side, 18-1 is an example of a camshaft,] 8-2 is a camshaft on the other side, 20 is a space, 22-1 is an example Hesode cover, 22-2 is the hend force bar on the other side, 24 is the crank gear, 26-1 is an example of a cam gear, 26-2 is an example of a cam gear on the other side, 28-1 is an example of an intermediate gear train, 28-2 is an example of a side intermediate gear Row 28-1.30 is a reduction gear train, 32 is an axis, 3
Reference numeral 4-1 is an axially-side end surface of the cylinder bank 4-1, and 34-2 is an axially-side end surface of the other cylinder bank 4-2.

Claims (1)

[Claims] 1. A crank gear is provided on the crankshaft that is supported by the cylinder block of the V-type engine, and each side cam gear is provided on each side camshaft that is supported by each side cylinder head of each side cylinder bank of the V-type engine. In the camshaft drive mechanism of a type engine, the camshafts are provided so that the camshafts on each side are meshed with the crankshaft via intermediate gear trains on each side, respectively, in order to drive the camshafts on each side to rotate in opposite directions to each other. A reduction gear train is provided that meshes with the gear and the intermediate gear train on each side to reduce and transmit driving force, and the reduction gear train is biased to one side of the cylinder bank on each side with respect to the crank gear. A camshaft drive mechanism for a V-type engine, which is characterized by being arranged as follows.