JP2015108395A - Damper pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damper pulley which can prevent adhesion with a crank shaft, and can easily perform attachment/detachment.SOLUTION: A damper pulley 10 comprises: a hub 1 which is composed of a cylindrical boss part 1a, a hub side face part 1b extending to the outside of a radial direction from the boss part 1a, and a cylindrical rim part 1c arranged at an external peripheral side of the hub side face part 1b in the radial direction; and a damper mass 2 which has a pulley groove part 2b at an external peripheral face, and is attached to the rim part 1c via an elastic body 3. A tip part 9c of a crank shaft 9 is made to penetrate the boss part 1a, and the tip part 9c of the crank shaft 9 is fastened to an end face of the boss part 1a with a set bolt 7. In the set bolt 7, a recess 7b is formed at a seat face 7a, and the tip part 9c of the crank shaft 9 which penetrates the boss part 1a is positioned at the end face of the boss part 1a, or positioned while slightly protruding from the end face of the boss part 1a, and fastened in a state that a clearance e in an axial direction is formed between the seat face 7a of the set bolt 7 and the tip part 9c of the crank shaft 9.

Description

  The present invention relates to a damper pulley that is attached to a rotating shaft such as a crankshaft of an automobile engine and attenuates torsional vibration.

  A reciprocating engine, which is an internal combustion engine, is used as a driving force of an automobile, and this engine employs a system that converts a reciprocating motion of a piston into a rotational motion by a crankshaft. The crankshaft is rotated with rotational fluctuations (torque fluctuations) because rotational forces due to the explosion force and inertial force of each cylinder of the engine periodically act on the crankshafts. The rotation of the crankshaft is used not only for driving force but also for rotationally driving auxiliary equipment such as a water pump and an air conditioner compressor. For this reason, a damper pulley in which a damper function is added to a pulley that transmits the rotational power of the crankshaft to an auxiliary machine is used as one of the dampers that reduces vibrations caused by rotational fluctuations of the crankshaft. The rotation of the crankshaft is transmitted by winding a belt around a damper pulley attached to the tip and a pulley attached to the accessory.

  This damper pulley has a cylindrical boss provided at the outer peripheral end of the hub side surface, a hub side surface extending radially outward from the boss, and a cylindrical boss portion through which the tip of the crankshaft is inserted. And a damper mass having a pulley groove portion on the outer peripheral surface and attached to the rim portion via an elastic body. The boss portion is rotatably supported by a support portion of the front cover via an oil seal, and the inside of the front cover is sealed in a liquid-tight manner by an oil seal. A rubber material is generally used for the elastic body, and the torsional vibration accompanying the rotation input from the crankshaft to the hub is damped by the viscous effect of the elastic body. Also, the spring effect of the elastic body is used to attenuate the vibration system composed of the damper mass and the elastic body by the resonance of the crankshaft, and exhibits the vibration damping effect together with the damping due to the viscous effect.

  By the way, since the damper pulley may be detached, for example, during engine maintenance, the damper pulley can be easily detached. For example, Patent Document 1 discloses a damper pulley in which a tip end portion of a crankshaft is inserted into a boss portion of a damper pulley, and the tip end portion of the crankshaft is fastened to an end surface of the boss portion with a set bolt. As shown in FIG. 2, the damper pulley 100 can be easily detached by fastening and releasing the set bolt 107.

JP 2011-252567 A

  The damper pulley 100 is configured such that when the set bolt 107 is fastened, the distal end portion 109c of the crankshaft 109 is positioned on the inner peripheral surface of the boss portion 101a that is retracted in the axial direction from the end surface of the boss portion 101a. This is because if the front end portion 109c of the crankshaft 109 protrudes from the end surface of the boss portion 101a, the crankshaft 109 interferes with the seat surface of the set bolt 107 and cannot be fastened.

  On the other hand, while the engine is driven and the crankshaft 109 rotates, the crankshaft 109 constantly vibrates. Due to the vibration of the crankshaft 109, the tip portion 109c of the crankshaft 109 may contact the inner peripheral surface of the boss portion 101a, and a metallic bond (adhesion) may occur on this contact surface. The damper pulley 100 that has adhered to the crankshaft 109 cannot be easily detached even if the set bolt 107 is released, and the crankshaft 109 may be damaged if it is forcibly detached. There was a problem that it took time and effort.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a damper pulley that prevents adhesion to the crankshaft and can be easily detached.

  According to a first aspect of the present invention, there is provided a cylindrical boss portion through which a tip end portion of a crankshaft of an internal combustion engine is inserted, a hub side surface portion extending radially outward from the boss portion, and a diameter of the hub side surface portion. A hub comprising a cylindrical rim provided at the outer peripheral end in the direction, and a damper mass having a pulley groove on the outer peripheral surface and attached to the rim via an elastic body, and the crank on the boss In the damper pulley in which the tip end portion of the shaft is inserted and the tip end portion of the crankshaft is fastened to the end surface of the boss portion by a set bolt, the set bolt has a recess formed in a seating surface and is inserted through the boss portion. The front end portion of the crankshaft is positioned slightly projecting from the end surface of the boss portion or the end surface of the boss portion, and between the seat surface of the set bolt and the front end portion of the crankshaft. Characterized in that it is fastened in a state of forming an axial clearance.

  According to the invention of claim 1 configured as described above, in a state where the damper pulley is fixed to the crankshaft, the tip end portion of the crankshaft is located slightly protruding from the end surface of the boss portion or the end surface of the boss portion. Yes. Thereby, even if the crankshaft vibrates, the tip end portion of the crankshaft and the inner peripheral surface of the boss portion do not come into contact with each other, so that no adhesion with the crankshaft occurs. Therefore, it can remove | desorb easily by releasing | fastening the fastening of a set bolt. In addition, the recess formed on the seat surface of the set bolt forms a gap between the seat surface of the set bolt and the tip of the crankshaft. Therefore, when fastening the set bolt, the seat surface of the set bolt and the crankshaft It is possible to fasten securely without interfering with the front end portion.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing adhesion with a crankshaft, the damper pulley which can be removed easily can be provided.

It is side surface sectional drawing which shows the damper pulley which concerns on embodiment of this invention. It is side surface sectional drawing which shows the conventional damper pulley.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The damper pulley 10 of the present embodiment is attached to a crankshaft as a rotating shaft of an engine which is an internal combustion engine (not shown). As shown in FIG. 1, the damper pulley 10 includes a cylindrical boss 1a through which the tip 9c of the crankshaft 9 is inserted, a hub side 1b extending radially outward from the boss 1a, and a hub side. A hub 1 composed of a cylindrical rim portion 1c provided at the radially outer peripheral end of the portion, and a damper mass 2 having a pulley groove portion 2b on the outer peripheral surface and attached to the rim portion 1c via an elastic body 3. Prepare.

  The hub 1 is made of a metal material such as cast iron, and includes a boss portion 1a that is fixed to the tip end portion 9c of the crankshaft 9, a hub side surface portion 1b that extends radially outward from the boss portion 1a, and a boss portion 1a. It has a cylindrical rim portion 1c that extends to the front side (left side in FIG. 1) and is provided at the radially outer peripheral end of the hub side surface portion 1b.

  The damper mass 2 is made of a metal material such as cast iron, and a pulley groove portion 2b is formed on the outer peripheral surface for winding a belt and transmitting a rotational force to the auxiliary machine.

  The elastic body 3 is made of an elastic material such as EPDM (ethylene / propylene rubber), is formed in an annular shape, and is disposed between the inner peripheral surface 2a of the damper mass 2 disposed to face the outer peripheral surface 1d of the rim portion 1c, It is fitted with a predetermined compression allowance.

  The outer peripheral surface 1d of the rim 1c and the inner peripheral surface 2a of the damper mass 2 have a shape that undulates in the radial direction in order to suppress axial movement of the damper mass 2 and the hub 1 relative to the hub 1.

  A half-moon key 11 is formed on the inner peripheral surface of the boss portion 1 a, and the half-moon key 11 is fitted in a half-moon-shaped groove 9 a formed on the outer peripheral surface of the shaft portion of the crankshaft 9. The distal end portion 9c of the crankshaft 9 inserted through the boss portion 1a is located slightly protruding from the end surface of the boss portion 1a.

  A thread groove 9b is formed at the tip 9c of the crankshaft 9, and a set bolt 7 is screwed into the thread groove 9b. The set bolt 7 is composed of a hexagonal head and a threaded portion that engages with the thread groove 9b of the crankshaft 9, and the seat surface 7a has a recess 7b and an annular portion 7c formed around the cylindrical portion. .

  The set bolt 7 is screwed into the thread groove 9b so as to be pressed against a stepped portion (not shown) of the crankshaft 9, and is clamped by the stepped portion of the crankshaft 9 by the fastening force of the set bolt 7. A damper pulley 10 is fixed to the crankshaft 9.

  As described above, the boss portion 1 a is fixed to the crankshaft 9 so as not to move in the axial direction and the rotational direction of the crankshaft 9, and rotates integrally with the crankshaft 9.

  With the damper pulley 10 fixed to the crankshaft 9, there is a slight radial gap between the outer peripheral surface of the shaft portion of the crankshaft 9 and the inner peripheral surface of the boss portion 1a. Further, the end surface of the boss portion 1a and the annular portion 7c of the seating surface 7a of the set bolt 7 are in contact with each other, and the tip end portion 9c of the crankshaft 9 is positioned facing the recess 7b of the seating surface 7a of the set bolt 7. . Thus, an axial gap e is formed between the seating surface 7 a of the set bolt 7 and the tip end portion 9 c of the crankshaft 9.

  The front cover 5 constitutes a part of an engine case. A support portion 5 a is formed on the front cover 5, and a boss portion 1 a of the hub 1 is rotatably supported on the support portion 5 a via an oil seal 8.

  Oil for lubricating the timing chain and the like circulates between the engine cylinder block (not shown) and the front cover 5, and the oil seal 8 is connected to the boss portion 1 a and the support portion 5 a of the front cover 5. By interposing between them, oil is prevented from leaking outside the front cover 5.

  According to the above configuration, as shown in FIG. 1, in the damper pulley 10, the torsional vibration accompanying the rotation of the crankshaft 9 is damped by the viscous effect of the elastic body 3. Further, due to the spring effect of the elastic body 3, the elastic body 3 is damped by resonance between the vibration system composed of the damper mass 2 and the elastic body 3 and the crankshaft 9. As described above, the rotation of the crankshaft 9 is transmitted from the hub 1 to the damper mass 2 via the elastic body 3, and is further wound around the pulley groove 2 b on the outer peripheral surface of the damper mass 2 (not shown). To be transmitted to the auxiliary machine.

  And even if the crankshaft 9 vibrates, since the front-end | tip part 9c of the crankshaft 9 and the internal peripheral surface of the boss | hub part 1a do not contact | abut the damper pulley 10, adhesion with the crankshaft 9 does not arise. Therefore, the damper pulley 10 can be easily detached by releasing the fastening of the set bolt 7.

  Further, an axial gap e is formed between the seat surface 7 a of the set bolt 7 and the tip end portion 9 c of the crankshaft 9 by the recess 7 b formed in the seat surface 7 a of the set bolt 7. Therefore, when the set bolt 7 is fastened, the seating surface 7a of the set bolt 7 and the tip end portion 9c of the crankshaft 9 do not interfere with each other and can be fastened securely.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims. For example, in this embodiment, although the recessed part is formed in the seat surface of a set bolt, you may combine a washer which formed the set bolt and the recessed part.

DESCRIPTION OF SYMBOLS 1,101: Hub, 1a, 101a: Boss part, 1b: Hub side part, 1c: Rim part,
1d: outer peripheral surface, 2,102: damper mass, 2a: damper mass inner peripheral surface,
2b: pulley groove portion 3, 103: elastic body, 5,105: front cover,
5a: support part, 106: washer, 7, 107: set bolt, 7a: bearing surface,
7b: recessed portion, 7c: annular portion, 8, 108: oil seal,
9, 109: crankshaft, 9a: groove, 9b: thread groove, 9c: tip portion,
10, 100: Damper pulley, 11: Half moon key

Claims (1)

A cylindrical boss portion through which a tip of a crankshaft of an internal combustion engine is inserted, a hub side surface portion extending radially outward from the boss portion, and a cylinder provided at a radially outer peripheral end of the hub side surface portion A hub having a rim-like shape, a pulley groove on the outer peripheral surface, and a damper mass attached to the rim via an elastic body, and the tip of the crankshaft is inserted into the boss. In the damper pulley in which the tip end portion of the crankshaft is fastened to the end surface of the boss portion by a set bolt,
The set bolt has a recess formed in a seat surface, and a tip end portion of the crankshaft inserted through the boss portion is positioned slightly projecting from an end surface of the boss portion or an end surface of the boss portion, and the set bolt A damper pulley, wherein the damper pulley is fastened in a state where an axial gap is formed between a seat surface of the crankshaft and a tip end portion of the crankshaft.

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