JPH0241301Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The invention relates to an engine belt drive device.
More specifically, the present invention relates to cooling measures for an accessory drive belt for transmitting the driving force of an engine drive shaft to an accessory.

(Prior Art) Generally, in an engine equipped with an auxiliary machine, an auxiliary drive belt is wound between the engine drive shaft and the driven shaft of the auxiliary machine on one side of the engine, and the drive shaft drives the auxiliary machine. The auxiliary equipment is driven via a drive belt.

(Problem that the invention aims to solve) However, when such an engine is mounted horizontally on the car body with its drive shaft facing left and right of the car body, the auxiliary drive belt faces the side of the car body. Due to the arrangement, it is difficult for the auxiliary drive belt to be exposed to the traveling wind, making it more likely to overheat.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and is designed to cool the accessory drive belt in a good manner, especially on the premise that the camshaft drive method of the engine is via a reduction gear.

That is, as an engine camshaft drive system, for example, as disclosed in Japanese Utility Model Application Publication No. 59-35603, in order to make the engine more compact,
Some devices have a reduction gear disposed between the drive shaft and the camshaft to keep the diameter of the camshaft pulley or sprocket small. In such a camshaft drive system via a reduction gear, a chain or a timing belt, etc. of the drive shaft side transmission part that transmits the driving force of the engine drive shaft to the reduction gear, and a camshaft that transmits the rotational force of the reduction gear to the camshaft. Because the chain or timing belt or the like of the side transmission section intersects with the reduction gear, one of the transmission sections is disposed outside the engine, and there is a misalignment in the position of both transmission sections in the drive shaft direction. By focusing on this positional discrepancy and appropriately arranging the two transmission parts and the accessory drive belt, a cooling passage for the accessory drive belt can be formed well, making the engine more compact. The objective is to cool the auxiliary drive belt well.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention is mounted horizontally with the drive shaft facing left and right of the vehicle body, and transmits the driving force of the drive shaft through a reduction gear. This assumes an engine that transmits the power to the camshaft. The camshaft side transmission section that transmits the rotational force of the reduction gear to the camshaft is disposed on the outer side of the engine than the drive shaft side transmission section that transmits the driving force of the drive shaft to the reduction gear, and is located on the camshaft side. The cover that covers the transmission section and the drive shaft side transmission section has an upper section that covers the camshaft side transmission section and a cover that covers the camshaft side transmission section that covers the engine. It protrudes outward, and the side surface of the upper section on the front side of the vehicle body is formed to be inclined toward the rear side of the vehicle body as it goes downward. Further, an accessory drive belt for transmitting the driving force of the drive shaft to the accessory is disposed below the upper part of the cover and on the outer side of the engine in the lower part.

(Function) With the above configuration, in the present invention, when the engine is mounted horizontally on the vehicle body, the side surface on the front side of the vehicle body in the upper part of the cover acts as a deflection plate, so that the running wind is directed to the vehicle body in the upper part of the cover. It is guided downward toward the rear of the vehicle body by the front side surface and hits the auxiliary drive belt below the upper stage, thereby cooling the auxiliary drive belt. Moreover, since it utilizes the deviation in the drive shaft side direction between the drive shaft side transmission section and the camshaft side transmission section that occurs due to the adoption of a reduction gear, the overall length of the engine is increased compared to a general engine with a reduction gear. Never.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

1 and 2 show a DOHC type engine equipped with a belt drive according to the invention.
This engine is mounted horizontally on a vehicle body so that its drive shaft (crankshaft) 3 faces in the left-right direction of the vehicle body (not shown). In FIGS. 1 and 2, 1 is a cylinder block, 2 is a cylinder head disposed on the cylinder block 1, and a crankshaft 3 as a drive shaft is supported at the bottom of the cylinder block 1. ing. On the other hand, camshafts 4 and 5 dedicated to intake and exhaust systems are supported on the upper part of the cylinder head 2 in parallel with the crankshaft 3, respectively.

Further, in the cylinder block 1, a reduction gear 6 is disposed between the crankshaft 3 and the camshafts 4 and 5 at the right end in the left-right direction of the vehicle body. The reduction gear 6 is an input side gear 6
A and an output gear 6b having half the number of teeth of the input gear 6a are directly connected to each other.

Further, gears 7, 8, and 9 having the same number of teeth are fixed to the right end of the crankshaft 2 and the right ends of the camshafts 4 and 5, respectively. A drive shaft chain 10 is connected between the gear 7 of the crankshaft 3 and the input gear 6a of the reduction gear 6.
is wound around to form the drive shaft side transmission section 11. On the other hand, a camshaft side chain 12 is wound between the output side gear 6b of the reduction gear 6 and each gear 8, 9 of the camshafts 4, 5 to constitute a camshaft side transmission section 13. The driving force is transmitted to the camshafts 4 and 5 via the reduction gear 6, so that the camshafts 4 and 5 are driven at one-half the rotation speed of the crankshaft 3.

Also, the output side gear 6b of the reduction gear 6 is located further outside the engine (on the left side in FIG. 2) than the input side gear 6a.
As a result, the camshaft side transmission section 13 is disposed further outward from the engine than the drive shaft side transmission section 11.

Furthermore, the cylinder block 1 is provided with the camshaft side transmission section 13 and the drive shaft side transmission section 1.
A cover 14 is attached to cover both of the transmission parts 11 and 13 to protect both the transmission parts 11 and 13. The cover covers the upper part 1 that covers the camshaft side transmission part 13.
4a is formed to protrude outward from the engine in correspondence with the camshaft side transmission section 13 which is disposed on the engine outward side with respect to the lower section covering the drive shaft side transmission section 11, and the upper section 14a is formed to protrude outward from the engine. The front side (right side in FIG. 1) is formed to be inclined toward the rear of the vehicle body as it goes downward so as to deflect the traveling wind downward.

Further, an alternator 15 and a water pump 16 are disposed on the engine outer side of the cover 14 and below the reduction gear 6, that is, below the upper section 14a. Pulleys 17, 18, and 19 are fixed to the driven shafts of the crankshaft 3, the alternator 15, and the water pump 16, respectively. 20 is wound around it, and the driving force of the crankshaft 3 is transmitted to the alternator 15 and water pump 16 via this accessory drive belt 20. As described above, the positional relationship is set such that the accessory drive belt 20 is disposed below the upper stage part 14a of the cover 14 and on the outer side of the engine in the lower stage part.

In addition, 21 and 22 are chains 10 and 12, respectively.
It is a chain tensioner that guides the

Therefore, in the above embodiment, the cover 1
Since the side surface of the upper stage part 14a of the cover 4 on the front side of the vehicle body acts as a deflection plate, the running wind is guided downward from the front side of the vehicle body to the rear side of the vehicle body by the side surface of the upper stage part 14a of the cover front side of the vehicle body. Since it hits the auxiliary drive belt 20 below the upper stage part 14a, it eliminates the insufficient cooling of the auxiliary drive belt 20 due to the horizontal placement of the engine, cools the auxiliary drive belt 20 well, and prevents its overheating as much as possible. can do.

In addition, since the cover upper part 14a is formed to protrude by taking advantage of the misalignment in the crankshaft direction between the drive side transmission section 11 and the camshaft side transmission section 13 caused by the adoption of the reduction gear 6, it can be used in a general engine with a reduction gear. The overall length of the engine does not increase compared to the camshaft 4, which uses a reduction gear 6.
Coupled with the reduction in diameter of the gears 8 and 9 of No. 5, the engine can be made compact.

In the above embodiment, the drive shaft side transmission section 11 and the camshaft side transmission section 13 are configured by a chain transmission mechanism, but they may also be configured by a belt transmission mechanism or other various wrap transmission mechanisms.

In addition to the DOHC type of the above example,
Of course, the present invention can also be applied to chains with reduction gears or belt transmissions in other types of engines such as SOHC types.

(Effects of the invention) As explained above, according to the engine belt drive device of the invention, in a horizontal engine in which the driving force of the drive shaft is transmitted to the camshaft via the reduction gear, the camshaft side transmission section The upper part of the cover covering the camshaft side transmission part and the drive shaft side transmission part is arranged to protrude in correspondence with the camshaft side transmission part, and the upper part of the cover covering the camshaft side transmission part and the drive shaft side transmission part is arranged on the front side of the vehicle body. The side surface is formed so that it slopes toward the rear of the vehicle body as it goes downwards, and an accessory drive belt that transmits the driving force of the drive shaft to the accessory is placed below the upper part of the cover, making it similar to the general case. Compared to engines with reduction gears, the overall length of the engine is not increased, and even when the engine is placed horizontally, the running air is deflected by the upper part of the cover and applied to the auxiliary drive belt, allowing the auxiliary drive belt to be cooled well. However, overheating can be effectively prevented.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a side view and FIG. 2 being a longitudinal sectional side view of FIG. 3... Crankshaft, 4, 5... Camshaft, 6... Reduction gear, 11... Drive shaft side transmission section, 13... Camshaft side transmission section, 14... Cover, 14a... Upper section, 15... Alternator, 16...Water pump, 20...Auxiliary drive belt.

Claims (1)

[Scope of utility model registration request] A camshaft that transmits the rotational force of the reduction gear to the camshaft in an engine that is mounted horizontally with the drive shaft oriented in the left-right direction of a vehicle body and that transmits the driving force of the drive shaft to the camshaft via a reduction gear. The side transmission section is arranged outward of the engine from the drive shaft side transmission section that transmits the driving force of the drive shaft to the reduction gear, and the cover that covers the camshaft side transmission section and the drive shaft side transmission section is arranged on the camshaft side transmission section. An upper stage part covering the side transmission part protrudes outward from the engine in correspondence with the camshaft side transmission part disposed on the engine outer side than a lower stage part covering the drive shaft transmission part, and the upper part covers the front side of the vehicle body. The side surface is formed to be inclined toward the rear of the vehicle body as it goes downward, and the drive force of the drive shaft is transmitted to the auxiliary equipment below the upper part of the cover and on the outer side of the engine in the lower part. A belt drive device for an engine, characterized in that an auxiliary drive belt is arranged.