JP2022155117A - crank pulley - Google Patents

Abstract

To suppress abnormal noise which is emitted from a crank pulley resulting from vibration of a rotating crank shaft.SOLUTION: A crank pulley includes: a pulley body; and a set bolt which fixes the pulley body to an end of a crank shaft. The set bolt includes: an elastic member provided at the interior; and a mass part supported by the elastic member. The mass part provided at the inner side of the elastic member may vibrate and vibrates so as to cancel out vibration occurring in the crank shaft to suppress abnormal noise emitted from the crank pulley.SELECTED DRAWING: Figure 1

Description

The present invention relates to crank pulleys.

2. Description of the Related Art Conventionally, a crank pulley for belt-driving accessories provided in an internal combustion engine is attached to the tip of a crankshaft provided in the internal combustion engine. The crank pulley includes a disk-shaped pulley body and a set bolt that secures this to the tip of the crankshaft. Crank pulleys sometimes generate noise when they operate. In order to reduce this noise, the pulley body is provided with a rubber frame or sound insulating plate, or the pulley body is filled with sound absorbing material (for example, , see Patent Document 1).

JP-A-7-269679

By the way, in an internal combustion engine, a bearing provided at the bottom of a cylinder block rotatably supports a crank journal of a crankshaft. A crankshaft converts the reciprocating motion of a piston within a cylinder provided within an internal combustion engine into rotary motion. At that time, a collision occurs between the crank journal and the bearing portion, which may cause the crankshaft to vibrate. When such vibrations of the crankshaft are propagated to the crank pulley, the crank pulley may generate abnormal noise. In the crank pulley disclosed in Patent Document 1, the pulley body is devised to reduce noise. It's not working.

Accordingly, an object of the invention disclosed in this specification is to suppress abnormal noise emitted from a crank pulley due to vibration of a rotating crankshaft.

A crankshaft disclosed in this specification includes a pulley body and a set bolt for fixing the pulley body to an end of the crankshaft, the set bolt including an elastic member provided therein and a and a supported mass.

INDUSTRIAL APPLICABILITY The invention disclosed in this specification can suppress abnormal noise emitted from a crank pulley due to vibration of a rotating crankshaft.

FIG. 1 is a cross-sectional view of a crank pulley according to an embodiment and a distal end portion of a crankshaft to which the crank pulley is mounted. FIG. 2 is a sectional view of the crank pulley of the embodiment and the distal end portion of the crankshaft with the crank pulley removed. FIG. 3(A) is a front view of the set bolt of the embodiment, and FIG. 3(B) is a side view of the set bolt of the embodiment. FIG. 4 is a sectional view taken along the line AA in FIG. 3(A).

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, etc. of each part may not be illustrated so as to completely match the actual ones. In some drawings, details may be omitted.

(embodiment)
First, a schematic configuration of a crank pulley 10 according to an embodiment will be described with reference to FIGS. 1 and 2. FIG. The crank pulley 10 has a pulley body 11 and a set bolt 12. - 特許庁The crank pulley 10 is fixed to a distal end portion 20a of a crankshaft 20 provided in an internal combustion engine mounted on a vehicle. The vehicle may be configured to run only by the internal combustion engine, or may be configured to run by switching between both the internal combustion engine and the motor for running the vehicle. Since the configuration of the internal combustion engine itself is a conventionally known general configuration, detailed description thereof will be omitted here.

The pulley body 11 has an annular rim portion 11a, a hub portion 11b arranged at the center thereof, and an arm portion 11c connecting the rim portion 11a and the hub portion 11b. A boss portion 11b1 is provided on the hub portion 11b. The boss portion 11b1 is provided with a recessed insertion portion 11d into which the tip portion 20a of the crankshaft 20 is inserted.

The crankshaft 20 has a crank journal 22 . Although only one crank journal 22 is shown in FIGS. 1 and 2 for convenience of explanation, the crankshaft 20 has crank journals at other positions along its axis AX. The crankshaft 20 is rotatably installed in the internal combustion engine by supporting these crank journals in bearings provided in the lower part of the cylinder block of the internal combustion engine.

A tip portion 20a of the crankshaft 20 is provided with a bolt hole 21 provided along the axis AX. The crank pulley 10 is fixed to the crankshaft 20 by screwing the set bolt 12 into the bolt hole 21 and tightening it in a state in which the tip portion 20a is inserted into the insertion portion 11d.

The set bolt 12 will now be described in detail with reference to FIGS. 3 and 4. FIG. The set bolt 12 includes a head portion 12a and a shaft portion 12b connected to the head portion 12a along the axis AX. The head portion 12a has a flange portion 12a1 at the boundary portion with the shaft portion 12b. A threaded portion 12b1 is provided on the outer peripheral surface of the shaft portion 12b. The set bolt 12 has a damping mechanism mounting hole 13 drilled from the end face on the head 12a side toward the shaft portion 12b side along the axis AX. A damping mechanism 14 is press-fitted into the damping mechanism mounting hole 13 .

The damping mechanism 14 includes a rubber member 14a, which is an example of an elastic member, and a mass portion 14b. The rubber member 14 a is provided so as to cover the circumference of the mass portion 14 b and is provided so that its outer peripheral surface is in contact with the inner peripheral surface of the damping mechanism mounting hole 13 . The mass portion 14b is supported by the rubber member 14a in the damping mechanism mounting hole 13 by arranging the rubber member 14a around the mass portion 14b. A mass portion 14 b supported by an elastic and deformable rubber member 14 a can be displaced within the damping mechanism mounting hole 13 . Therefore, the mass portion 14b can vibrate within the head portion 12a and the shaft portion 12b, which are rigid bodies. The mass portion 14b can cancel the vibration propagated from the crankshaft 20 by vibrating. The hardness of the rubber member 14a, the weight of the mass portion 14b, and the installation position of the mass portion 14b can be appropriately set by adaptation experiments and simulations using an actual internal combustion engine. Specifically, the frequency of vibration occurring in the crankshaft 20 is analyzed, and these parameters are set so that the damping mechanism 14 can cancel the vibration. The material of the mass portion 14b can be appropriately selected from materials that can satisfy these conditions. The rubber member 14a can also be changed to another material that can appropriately vibrate the mass portion 14b, or the mass portion 14b can be supported by another elastic member such as a spring.

Returning to FIGS. 1 and 2, the crank pulley 10 is configured by inserting the distal end portion 20a of the crankshaft 20 into the insertion portion 11d and tightening the set bolt 12 having the washer 15 inserted through the shaft portion 12b. Fixed at 20. As a result, the head portion 12a and the shaft portion 12b of the set bolt 12 are integrated with the crankshaft 20 as a rigid body. As the internal combustion engine operates, the crankshaft 20 may vibrate when the crank journal 22 strikes a bearing portion of the internal combustion engine. Since the set bolt 12 is integrated with the crankshaft 20 , it vibrates in the same manner as the crankshaft 20 , but the mass portion 14 b vibrates independently of the vibration of the crankshaft 20 . As a result, the vibration of the crankshaft 20 and the vibration of the mass portion 14b can be canceled out. As a result, noise generated from the crank pulley 10 can be suppressed.

According to the crank pulley 10 of the present embodiment, the set bolt 12 that fixes the pulley body 11 to the tip portion 20a of the crankshaft 20 is provided with the damping mechanism 14, so the vibration of the crankshaft 20 is canceled. As a result, noise generated by the crank pulley 10 due to vibration of the crankshaft 20 is suppressed.

Normally, a water pump (WP) and an air conditioner (AC) provided in a vehicle are driven by a drive belt that is wound around a crank pulley 10, but these days, WP and AC are electrified, and drive belts are not used. Sometimes. For example, when the vehicle is a hybrid vehicle equipped with an internal combustion engine and a driving motor, the WP or AC may be electrified and the drive belt may not be used. In this case, it is conceivable to abolish the crank pulley 10 itself. However, even if the vehicle is a hybrid vehicle, in consideration of cost, the internal combustion engine may not be modified in any way and may be installed with the same specifications as a conventional vehicle that runs on only the internal combustion engine. In this case, the crank pulley 10 is installed as it is. As a result, the vibration of the crankshaft 20 can be canceled even in a hybrid vehicle.

The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to these, and various modifications of these examples are within the scope of the present invention, and furthermore, It is self-evident from the above description that many other embodiments are possible within the scope.

10 crank pulley 11 pulley body 11a rim portion 11b hub portion 11b1 boss portion 11c arm portion 11d insertion portion 12 set bolt 12a head portion 12a1 flange portion 12b shaft portion 12b1 screw portion 13 damping mechanism mounting hole 14 damping mechanism 14a rubber member 14b mass Part 20 Crankshaft 20a Tip 21 Bolt hole 22 Crank journal

Claims (1)

a pulley body;
a set bolt that secures the pulley body to the end of the crankshaft;
The set bolt includes an elastic member provided inside; a mass portion supported by the elastic member;
Crank pulley with

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