JP2013155823A - Pulley for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water drops adhered to an outer surface of a crank pulley from flowing into a timing belt chamber from a through hole of a cover in an internal combustion engine wherein the crank pulley and a timing pulley are fixed to ends of a crank shaft.SOLUTION: A timing pulley is fixed to an outer peripheral part of an end 1a of a crank shaft 1, and a crank pulley 3 is fixed to an end surface of the crank shaft 1. A cover 6 is disposed between a timing belt 5 and the crank pulley 3, and the cover 6 includes a through hole 7 wherein the crank shaft 1 loosely fits. A surface of the crank pulley 3, which faces the cover 6, is formed with an annular groove 16, into which water drops W flow. The water drops W flow downward from the annular groove 16 to a part below the through hole 7, without flowing into a timing belt chamber S.

Description

  The present invention relates to a pulley disposed close to the outer surface of an engine body, such as a crank pulley that transmits the power of a crankshaft to accessories.

  In an internal combustion engine, a timing pulley (or sprocket) and an auxiliary machine driving crank pulley are fixed to one end of the crankshaft that protrudes outside the cylinder block, and a valve mechanism is provided for the timing pulley (or sprocket). A driving timing belt (or chain) is wound around the crank pulley, and an accessory driving belt is wound around the crank pulley.

  In this case, the crank pulley and the accessory drive belt are exposed to the outside, but the timing belt (or sprocket) and the timing pulley (or chain) are covered with a cover that forms part of the engine body, and the timing belt A chamber is formed, and the cover has a through hole into which the crankshaft fits with a margin.

  On the other hand, water droplets may adhere to the pulley, and as a technique for removing water adhering to the pulley there is disclosed Patent Document 1 that provides a drain hole communicating with the belt groove. Discloses that a drain hole is provided in a disk portion of a pulley made of sheet metal.

JP 2000-257701 A Japanese Utility Model No.58-118353

  For example, in the case of an internal combustion engine for a vehicle, water in the air may aggregate due to the engine being stopped, and the water droplets may adhere to the side surface of the crank pulley. In this case, there is no problem because the water droplets attached to the surface opposite to the engine body are blown off to the outside of the engine when the internal combustion engine is started. And may enter the timing belt chamber from the through hole provided in the cover. If the water adheres to the timing belt, abnormal noise may occur or the strength of the timing belt may decrease. There was a risk of rusting the member.

  However, Patent Documents 1 and 2 remove water adhering to the pulley, but cannot prevent water from entering the timing belt chamber. Therefore, conventionally, no countermeasure has been taken against water intrusion into the timing belt chamber.

  The present invention has been made to improve the current situation.

  The present invention relates to a pulley that is arranged in the state of being close to the outer surface of the engine body and is fixed to an end portion of a rotary shaft that protrudes laterally from a through hole provided in the engine body. In the configuration in which the disk-shaped part is fixed to the rotating shaft, and the disk-shaped part of the disk-shaped part is a part of the disk-shaped part. An annular groove into which water droplets that hang down along the outer surface of the disk-like portion enter a portion facing the outer surface of the engine body so as to be located outside the through hole provided in the engine body. It is characterized by that. The “pulley” of the present invention includes a sprocket around which a chain is wound.

  According to the present invention, even if water droplets adhere to the end face of the pulley facing the engine body, the water drops flow down the annular groove along the end face of the pulley, and flow down from the annular groove to the lower side of the through hole. Therefore, it is possible to accurately prevent a phenomenon such as water intrusion into the timing belt chamber, and to prevent troubles caused by water intrusion.

  In addition, although water droplets may adhere to the outer surface of the engine body, in the present invention, the water droplets flowing along the outer surface of the engine body are guided so as to enter the annular groove of the pulley. It is also possible to prevent water droplets from entering the belt chamber. In particular, when a flange (or rib) that enters the annular groove of the pulley is provided on the outer surface of the engine body as in the embodiment, water drops that fall down along the engine body can be accurately guided to the annular groove. This is suitable because it is possible to accurately prevent troubles caused by water droplets adhering.

It is a vertical side view of 1st Embodiment. (A) is a vertical side view of the second embodiment, and (B) is a vertical side view of the first embodiment.

(1). First Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. First, the first embodiment shown in FIG. 1 will be described. In FIG. 1, reference numeral 1 denotes a crankshaft, and portions near both ends of the crankshaft 1 are rotatably held by a pair of main journals provided in a cylinder block (not shown). One end and the other end of the crankshaft 1 are exposed to the outside of the cylinder block, and a main driving timing pulley 2 for driving the valve operating mechanism and an auxiliary machine are driven to one end portion 1a of the crankshaft 1 among them. The crank pulley 3 is fixed.

  The main driving timing pulley 2 is fixed to a collar 4 fitted to one end 1a of the crankshaft 1 by welding or key engagement, and the collar 4 is fixed to the crank pulley 3 by key engagement. A timing belt 5 for driving the valve mechanism is wound around the main driving timing pulley 2. Needless to say, the timing belt 5 is wound around the driven timing pulley on the side opposite to the main driving timing pulley 2.

  The main driving timing pulley 2 and the timing belt 5 are covered with a cover 6 that constitutes a part of the engine body, whereby a timing belt chamber S is formed between the cylinder block and the cover 6. The crank pulley 3 is arranged in the state close to the cover 6. The cover 6 has a through hole 7 into which the crankshaft 1 is fitted with a margin. Therefore, a certain amount of space is provided between the inner peripheral surface of the through hole 7 and the crankshaft 1.

  The crank pulley 3 is made of sheet metal, and has a cylindrical outer peripheral portion (cylindrical portion) 9 formed on the outer peripheral surface with a belt groove 9 a into which the accessory driving belt 8 is fitted, and the cover 6 among the end surfaces of the outer peripheral portion 9. It has a disk-like part (rim part) 10 integrally connected to a near end, and the inner peripheral part 10a of the disk-like part 10 is an end face of the collar 4 with a bolt 11 screwed into the crankshaft 1. It is held down and fixed.

  An annular first flange 12 projecting outward is formed on the inner peripheral portion of the through hole 7 in the cover 6, and an annular second flange 13 and third flange 14 are also formed on the outer side thereof. doing. The projecting dimension of the first flange 12 is larger than the projecting dimensions of the second flange 13 and the third flange 14 (the flange can also be referred to as a rib).

  A small-diameter cylindrical portion 15 that enters the inside of the cover 6 is formed in a portion of the crank pulley 3 that is radially inward of the through hole 7 of the cover 6, and is fixed to the crankshaft 1 at the tip of the small-diameter cylindrical portion 15. The inner peripheral portion 10a is integrally formed. By forming the small-diameter cylindrical portion 15, the disc-like portion 10 of the crank pulley 3 has a convex shape when viewed from the side, but for convenience, a portion (small-diameter) continuous to the outer peripheral portion 9 of the disc-like portion 10. The outer portion of the cylindrical portion 13) is referred to as an outer disc portion 10b.

  And the annular groove 16 opened in the direction of the cover 6 is formed by expanding the connection part of the outer side disc part 10b and the small diameter cylinder part 15 to the opposite side to the cover 6. FIG. Since the annular groove 16 is formed by sheet metal processing, the whole is rounded. Further, the inner portion of the annular groove 16 enters the rotation center side of the crank pulley 3, and therefore the inner diameter D <b> 1 of the annular groove 16 is smaller than the maximum outer diameter D <b> 2 of the small diameter cylindrical portion 15. Further, the tip of the first flange 12 in the cover 6 is located at the opening of the annular groove 16.

  In the above configuration, even if water in the engine room aggregates after the engine is stopped and water droplets W adhere to the side surface of the crank pulley 3 facing the cover 6, the water droplets W travel along the side surface of the disk-shaped portion 10. Then, it flows down into the annular groove 16 and flows down from the annular groove 16. In addition, since the tip of the first flange 12 is located at the opening of the annular groove 16, even if a water droplet adheres to a portion of the outer surface of the cover 6 that is above the through hole 7, the water droplet remains in the first flange 12. Then, it flows down to the annular groove 16 and flows down from the annular groove 16 to the lower side of the through hole 7.

  Therefore, even if water droplets adhere to the crank pulley 3 or the cover 6, the water droplets do not enter the timing belt chamber S. If the small-diameter cylindrical portion 15 is formed in the disc-like portion 10 as in the present embodiment, the crank pulley 3 can be brought as close to the cover 6 as possible without increasing the length of the crankshaft 1, and the disc-like shape is used. There is an advantage that the rigidity of the portion 10 can be increased.

(2). Other Embodiments / Others In the second embodiment shown in FIG. 2A, the annular groove 16 is formed by forming a tapered annular rib 18 on the outer surface of the disc-like portion 10. . The annular rib 18 is tapered (funnel shape) so that the outer diameter increases toward the tip. In this embodiment, the annular rib 18 is arranged outside the first rib 12 of the cover 6, but the annular rib 18 may be arranged inside the radius of the first rib 12 of the cover 6. Further, in both the present embodiment and other embodiments, the disc-like portion 10 may be simply a flat plate shape without providing the small-diameter cylindrical portion 15, or may be provided with a small-diameter cylindrical portion protruding on the opposite side to the cover 6. Is possible.

  In the third embodiment shown in FIG. 2 (B), when the small-diameter cylindrical portion 15 is provided in the disc-shaped portion 10, the plate-shaped washer 19 is overlapped on the inner peripheral portion 10 a inside the small-diameter cylindrical portion 15. A groove 16 is formed. The dish-shaped washer 19 is in an attitude that opens toward the small-diameter cylindrical portion 15. The dish-shaped washer 19 may be fixed to the disk-shaped part 10 by welding or the like, or may be disposed inside the disk-shaped part 10 during assembly of the internal combustion engine (they are integrally formed on the disk-shaped part 10). Is also possible.) In addition, it is preferable to align the outer periphery of the disc part 19 in the same position as the front-end | tip of the 1st flange 12 in the cover 6 (If the 1st flange 12 is formed in the taper shape extended toward the crank pulley 3, More preferred).

  The present invention can be embodied in various ways other than the above-described embodiment. For example, the application target is not limited to the crank pulley, and the present invention can also be applied to an idle pulley around which an auxiliary machine driving belt is wound. Needless to say, the pulley need not be a sheet metal product, and may be a cast product. A plurality of annular grooves may be formed in one pulley.

  The present invention can be embodied in a pulley for an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Crankshaft 2 Main drive timing pulley 3 Crank pulley 5 Timing belt 6 Cover which comprises a part of engine body 7 Through-hole 9 Outer peripheral part 10 Disc-like part 10a Inner peripheral part 10b Outer disc part 12-14 Annular flange 15 Small diameter cylinder part 16 Annular groove 16
S Timing belt chamber W Water drop

Claims (1)

A pulley that is arranged in the state of being close to the outer surface of the engine body and is fixed to an end of a rotating shaft that protrudes laterally from a through hole provided in the engine body,
In a configuration comprising an outer peripheral portion around which a belt is wound and a disc-like portion provided integrally with the outer peripheral portion, and the disc-like portion is fixed to the rotating shaft.
An annular groove is formed in a portion of the disk-shaped portion that faces the outer surface of the engine body so that water drops that fall along the outer surface of the disk-shaped portion enter.
Pulley for internal combustion engine.

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