JP6662060B2 - Crank pulley - Google Patents

Description

  The present invention relates to a crank pulley, and more particularly, to a crank pulley to which a damper device for reducing torsional vibration of a crankshaft is attached.

  2. Description of the Related Art Conventionally, a damper device that is mounted on a front end side of a crankshaft of an engine via a crank pulley and absorbs rotational fluctuation of the engine to reduce torsional vibration of the crankshaft has been put to practical use.

  As this type of damper device, for example, in Patent Document 1, an inertial body is accommodated in a casing main body fixed to a crank pulley, and a viscous liquid such as silicone oil is sealed in a gap between the casing main body and the inertial body. The structure is disclosed.

  Patent Document 2 discloses a damper in which an annular flange portion is formed on a crank pulley so as to protrude radially outward, and an inertia ring is integrally provided on a front surface of the flange portion via a rubber having a damper action. An apparatus is disclosed.

JP 2000-314450 A JP-A-59-81836

  By the way, the damper device self-heats by absorbing fluctuations in the rotation of the engine. However, if the temperature rises excessively, there is a problem that the durability is reduced. In particular, on the rear side of the damper device, many components are arranged, and since the fluidity of the air is poor, the heat radiation of the damper device tends to deteriorate. For this reason, if the fluidity of the air at the location cannot be ensured, the temperature of the damper device tends to rise excessively, and the durability may be easily reduced.

  Further, in the technique described in Patent Document 2 described above, a large number of ventilation holes for cooling the damper are provided in the crank pulley, but these ventilation holes are formed in a thick portion or a flange portion of the crank pulley at a long distance. Therefore, the rigidity of the crank pulley may be reduced.

  The disclosed technology aims to effectively suppress a rise in the temperature of the damper device.

  The disclosed technology is a crank pulley provided on a front end side of a crankshaft of an engine and to which a damper device is attached, wherein the first cylinder is formed in a cylindrical shape and an endless belt is wound around an outer cylindrical surface thereof. A second cylindrical portion formed in a cylindrical shape and projecting rearward from a rear end of the first cylindrical portion, and a damper device is fixed to a rear side edge thereof; and a second cylindrical portion. A third cylindrical portion, which is also formed in a small-diameter cylindrical shape, is provided to protrude rearward from a rear end of the second cylindrical portion, and has a rear end fixed to a front end of the crankshaft; A first ventilation hole formed through the cylinder wall of the cylinder portion from the inner cylinder surface to the outer cylinder surface to introduce air from inside the cylinder of the third cylinder portion to the back side of the damper device. It is characterized by.

  A plurality of bosses for inserting a bolt for fixing the third cylinder to the crankshaft are provided in the cylinder of the third cylinder, and the air inlet of the first ventilation hole is provided with the plurality of bosses. It may open between.

  The first ventilation hole may be formed by inclining its axis in a direction opposite or perpendicular to the rotation direction of the crank pulley.

  A cylindrical wall of the second cylindrical portion is formed so as to penetrate from the inner cylindrical surface toward the outer cylindrical surface, and is provided between the outer cylindrical surface of the second cylindrical portion and the damper device from within the second cylindrical portion. A second ventilation hole for introducing air into the space may be further provided.

  According to the disclosed technology, a rise in the temperature of the damper device can be effectively suppressed.

It is a typical sectional view showing the crank pulley and the damper device concerning one embodiment of the present invention. FIG. 1 is a schematic front view of a crank pulley according to an embodiment of the present invention as viewed from the front. It is a typical sectional view showing the crank pulley and the damper device concerning other embodiments of the present invention.

  Hereinafter, a crank pulley according to an embodiment of the present invention will be described with reference to the accompanying drawings. The same components are denoted by the same reference numerals, and have the same names and functions. Therefore, detailed description thereof will not be repeated.

  As shown in FIG. 1, a crank pulley 10 is fixed to a front end of a crankshaft 2 of the engine 1 by bolting. The crank pulley 10 has a substantially cylindrical shape whose outer diameter decreases stepwise from the front end to the rear end. More specifically, the crank pulley 10 has a front end side opened, a first cylindrical portion 11 in which a fan (not shown) is disposed in front of the first pulley 10, and a rear end protruding from the rear end of the first cylindrical portion 11. A second cylindrical portion 12 having a smaller diameter than the portion 11 and a third cylindrical portion 13 projecting rearward from a rear end of the second cylindrical portion 12 and having a smaller diameter than the second cylindrical portion 12. Have.

  A plurality of belt grooves 17 for winding an endless belt (not shown) are formed on the outer cylindrical surface of the first cylindrical portion 11. An annular flange portion 25 of a damper device 20 to be described later is fixed to a rear side surface of the second cylindrical portion 12 by bolting. A plurality of bosses 15 through which bolts 18 for fixing the crank pulley 10 to the crankshaft 2 are inserted extend in the third cylindrical portion 13 in the axial direction at predetermined intervals. A plurality of ventilation holes 14, which will be described in detail later, are formed through the cylindrical wall of the third cylindrical portion 13.

  The damper device 20 includes a cylindrical casing member 22 having an annular concave portion 21 opened on one side surface, a cover member 23 for closing an opening side of the concave portion 21 to define an annular closed space, and a casing member 22. The annular flange 25 protrudes radially inward from the inner cylinder surface and has a plurality of bolt insertion holes (not shown), and is housed in a closed space defined by the recess 21 and the cover member 23. An annular inertia body 26 and a viscous fluid 27 such as silicone oil sealed in a gap between the outer peripheral surface of the inertia body 26 and the inner peripheral surfaces of the recess 21 and the cover member 23 are provided.

  In the damper device 20, the annular flange portion 25 is fastened and fixed to the rear side surface of the second cylindrical portion 12 by bolts. In the present embodiment, the outer diameter of the annular flange portion 25 is formed slightly larger than the outer diameter of the second cylindrical portion 12. That is, when the damper device 20 is attached to the crank pulley 10, a minute clearance C is secured between the inner cylindrical surface of the casing member 22 and the outer cylindrical surface of the second cylindrical portion 12.

  Next, details of the ventilation hole 14 according to the present embodiment will be described.

  The ventilation hole 14 is formed to penetrate the cylindrical wall of the third cylindrical portion 13 in the radial direction from the inner cylindrical surface 13A toward the outer cylindrical surface 13B. More specifically, the vent hole 14 has one opening 14A located between the bosses 15 of the inner cylindrical surface 13A, and the other opening 14B located on the outer cylindrical surface 13B behind the damper device 20. It is formed so that. As shown in FIG. 2, in a front view (front view) of the crank pulley 10, the vent hole 14 is formed such that an axis thereof is inclined in a direction opposite to or perpendicular to the rotation direction R of the crank pulley 10. It has been extended. That is, even when the air sent from the fan (not shown) disposed in front of the crank pulley 10 into the cylinder is not sufficient, the rotation of the crank pulley 10 causes the rear side of the damper device 20 to pass through the ventilation hole 14. Has been forcibly introduced.

  As described in detail above, according to the present embodiment, the third cylindrical portion 13 of the crank pulley 10 is formed with the ventilation hole 14 penetrating the cylindrical wall from the inner cylindrical surface 13A toward the outer cylindrical surface 13B. As a result, the air is forcibly introduced from the ventilation holes 14 to the rear side of the cover member 23 as the crank pulley 10 rotates. Thereby, the air on the back side of the damper device 20 flows, and the temperature of the damper device 20 can be effectively reduced, and the durability of the damper device 20 can be ensured. Further, since the plurality of ventilation holes 14 are formed in the cylindrical wall of the third cylindrical portion 13 at a short distance in the radial direction, the rigidity of the crank pulley 10 can be effectively prevented from decreasing.

  The present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the spirit of the present invention.

  For example, as shown in FIG. 3, the second cylindrical portion 12 of the crank pulley 10 may be further provided with a second ventilation hole 19 extending from the inner cylindrical inner surface 12A to the outer cylindrical surface 12B. By providing such a second ventilation hole 19, air is introduced into the minute clearance C between the inner cylindrical surface 22A of the casing member 22 and the outer cylindrical surface 12B of the second cylindrical portion 12, and the damper The cooling efficiency of the device 20 can be reliably improved.

  In addition, the damper device 20 is not limited to the above embodiment, and can be widely applied to other known damper devices.

Reference Signs List 1 engine 2 crankshaft 10 crank pulley 11 first cylindrical portion 12 second cylindrical portion 13 third cylindrical portion 14 vent hole 15 boss portion 18 bolt 19 second vent hole 20 damper device 21 concave portion 22 casing member 23 cover member 25 annular flange Part 26 inertia body 27 viscous fluid

Claims (3)

A crank pulley that is provided at a front end side of a crankshaft of an engine and to which a damper device is attached,
A first cylindrical portion formed into a cylindrical shape and having an endless belt wound around the outer cylindrical surface thereof;
A second cylindrical portion which is formed in a cylindrical shape, is provided to protrude rearward from a rear end of the first cylindrical portion, and has a damper device fixed to a rear side edge thereof;
A third cylinder, which is formed in a cylindrical shape smaller in diameter than the second cylinder part, is provided to protrude rearward from a rear end of the second cylinder part, and has a rear end fixed to a front end of the crankshaft. Department and
A first ventilation hole formed through the cylinder wall of the third cylinder portion from the inner cylinder surface toward the outer cylinder surface to introduce air from inside the cylinder of the third cylinder portion to the back side of the damper device; equipped with a,
A plurality of bosses for inserting bolts for fixing the third cylinder portion to the crankshaft are provided in the cylinder of the third cylinder portion, and the air inlet of the first ventilation hole is provided with the plurality of boss portions. A crank pulley that opens between the crank pulleys. 2. The crank pulley according to claim 1, wherein the first ventilation hole is formed by inclining its axis in a direction opposite or perpendicular to a rotation direction of the crank pulley. 3. The cylindrical wall of the second cylindrical portion is formed so as to penetrate from the inner cylindrical surface toward the outer cylindrical surface, and is formed between the outer cylindrical surface of the second cylindrical portion and the damper device from within the second cylindrical portion. 3. The crank pulley according to claim 1 , further comprising a second ventilation hole for introducing air into the space .

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