JPH0651609U - Crankshaft pulley - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the cost because the moment of inertia is small and the amplitude of torsional vibration of the crankshaft is not increased, and the strength is required. [Structure] A pulley 4 attached to a connecting shaft portion 2 at one end of a crankshaft 1 for driving an auxiliary machine or the like in an engine.
In the above, the boss portion 5 fitted to the connecting shaft portion 2 of the crankshaft 1 and fastened and fixed by the fixing bolt 16 screwed to the shaft center portion of the connecting shaft portion 2 is made of a steel material, and the pulley portion 6 is used.
Are made of a material having a low specific gravity.
And the pulley portion 6 are connected by screwing screws 8 and 9 or other connecting means.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a crankshaft pulley which is attached to one end of a crankshaft in an engine and drives auxiliary machinery and the like.

[0002]

[Prior art]

 Conventionally, in order to drive the cam shaft and accessories of an engine, as shown in FIG. 5, a sprocket 33 for driving a cam shaft and a pulley for driving an accessory are attached to a connecting shaft portion 32 at one end of a crank shaft 31. 34 and the like are fitted and fixed. Specifically, the half-moon key groove 35 is formed in the fitting portion of the sprocket 33 and the pulley 34 in the connecting shaft portion 32, and the half-moon key 36 is fitted in the sprocket 33 and the boss of the pulley 34. The portion 38 is fitted to the connecting shaft portion 32, and the fixing bolt 39 in which the head contact plate portion 40 is engaged with the outer end surface of the pulley 34 is screwed to the shaft core portion of the connecting shaft portion 32. The pulley 34 and the sprocket 33 are fastened and fixed, and an oil seal 41 is fitted on the outer circumference of the boss portion 38 of the pulley 34. The pulley 34 is usually made of a steel material.

Further, the pulley 34 made of a steel material has a large inertial force, which causes a problem that the amplitude of torsional vibration with respect to the crankshaft 31 is increased. As disclosed in Japanese Patent No. 15861 and Japanese Utility Model Application Laid-Open No. 64-553 62, and shown in FIG. 5, a damper pulley structure in which an elastic body 42 is interposed between a boss portion and a pulley portion is adopted, and twisting is performed. It is known to absorb vibration.

[0004]

[Problems to be solved by the device]

 However, if the damper pulley structure is adopted for the pulley 34 as described above, there is a problem that the cost becomes high because the structure is complicated.

In order to reduce the moment of inertia of the pulley 34, it may be considered that the pulley 34 is made of an aluminum material or the like having a small specific gravity. However, the fixing bolt 39 is loosened due to a problem in strength, particularly the insufficient strength of the boss portion 38. However, there is a problem that it may not be put to practical use.

In view of such conventional problems, the present invention provides a low cost crankshaft pulley that has a small moment of inertia and does not increase the amplitude of torsional vibration of the crankshaft and has the required strength. The purpose is to do.

[0007]

[Means for Solving the Problems]

 The present invention relates to a crankshaft pulley which is attached to one end of a crankshaft for driving an auxiliary machine or the like in an engine, is fitted to one end of the crankshaft, and is screwed to the axial center part of the one end of the crankshaft. The boss portion fastened and fixed with the fixing bolts is made of a steel material, and the pulley portion is made of a material having a low specific gravity. The boss portion and the pulley portion are connected to each other.

[0008]

[Action]

 According to the present invention, the pulley part, which has a large turning radius and greatly influences the moment of inertia, is made of a material having a low specific gravity, and the boss part, which has a small turning radius and has a small influence on the moment of inertia, is made of a steel material. Since the overall moment of inertia can be reduced and the amplitude of the torsional vibration of the crankshaft can be reduced, and the boss is made of a steel material, sufficient strength can be ensured and there is no risk of loosening the fixing bolts. Since the pulley portion and the boss portion are connected to each other, the structure is simple and the manufacturing cost is low.

[0009]

【Example】

 Hereinafter, a first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 1 is a crankshaft, and a sprocket 3 for a camshaft drive chain and a pulley 4 for driving a cooling fan or a compressor for a cooler are attached to a connecting shaft portion 2 provided at one end of the crankshaft. Are fitted and fixed.

The sprocket 3 is disposed in contact with the step surface 2 a at the base end of the connecting shaft portion 2. The pulley 4 is composed of a boss portion 5 made of a steel material and a pulley portion 6 made of cast aluminum alloy, and the boss portion 5 is arranged in contact with the sprocket 3. A protruding step portion 7 is provided at an intermediate portion of the outer peripheral surface of the boss portion 5, and an outer peripheral surface on the tip end side of the connecting shaft portion 2 with respect to the protruding step portion 7 is provided in a direction opposite to the rotation direction of the crankshaft 1. A male screw 8 is formed, and a female screw 9 formed on the inner peripheral surface of the pulley portion 6 is screwed into the male screw 8 to connect the boss portion 5 and the pulley portion 6. The V-groove portion of the pulley portion 6 is subjected to a surface hardening treatment or a heat treatment as needed to prevent wear. An oil seal 11 attached to the crankshaft penetrating portion of the chain cover 10 is fitted on the outer peripheral surface of the boss portion 5 on the proximal end side of the connecting shaft portion 2 to seal the inside of the chain cover 10.

Further, a key groove 12 is formed in the connecting shaft portion 2 in order to make the sprocket 3 and the pulley 4 and the crankshaft 1 in phase with each other, and the key groove 12 is engaged with the inner periphery of the sprocket 3 and the boss portion 5. The protruding ridges 13 and 15 are formed.

A screw hole for fixing is formed in the shaft core portion of the connecting shaft portion 2, and a fixing bolt 16 is screwed into the screw hole. The fixing bolt 16 is provided with a contact plate portion 17 that engages with the outer end surface 5 a of the boss portion 5 of the pulley 4. By fastening the fixing bolt 16 to the screw hole of the shaft center portion of the connecting shaft portion 2, the pulley 4 and the sprocket 3 are positioned between the base end step surface 2 a of the connecting shaft portion 2 and the contact plate portion 17 of the fixing bolt 16. The power is transmitted from the crankshaft 1 by the frictional force.

According to the above configuration, when the crankshaft 1 rotates, the sprocket 3 fixed to the connecting shaft portion 2 causes the camshaft to rotate in synchronization with the crankshaft 1. Similarly, the boss portion 5 of the pulley 4 fixed to the connecting shaft portion 2 is also driven, and the pulley portion 6 is driven through the screwing of the male screw 8 and the female screw 9 in the direction opposite to the rotation direction. Auxiliary devices such as a cooling fan and a compressor are driven.

According to the configuration of the pulley 4, the pulley portion 6 having a large turning radius and having a large influence on the moment of inertia is made of an aluminum alloy having a low specific gravity, and the turning radius is small and the influence on the moment of inertia is small. Since the boss portion 5 is made of a steel material, the overall moment of inertia can be reduced, the amplitude of torsional vibration of the crankshaft 1 can be reduced, and the boss portion 5 is made of a steel material. The strength is secured and there is no risk of the fixing bolt 16 coming loose. Further, since the pulley portion 6 and the boss portion 5 are connected by the screws 8 and 9 in the direction opposite to the rotation direction of the crankshaft 1, the structure is simple and the manufacturing can be performed at low cost.

Next, a second embodiment will be described with reference to FIG. In this embodiment, a timing belt pulley 18 is fitted and fixed to the connecting shaft portion 2 instead of the sprocket 3, and the crankshaft 1 and the cam shaft are interlockingly connected by a timing belt. The same pulley 4 as is used. Since the timing belt is used in this embodiment, the chain cover 10 is not provided.

Next, a third embodiment will be described with reference to FIG. In this embodiment, the coupling structure of the boss portion 5 of the pulley 4 and the pulley portion 6 is different from that of the first embodiment. That is, a flange portion 21 is provided on the outer circumference of the boss portion 5, the mounting plate portion 22 on the inner circumference of the pulley portion 6 is overlapped with the flange portion 21, and a plurality of circumferential positions are fastened and fixed by coupling bolts 23. There is.

In this embodiment, a sprocket 19 for driving a water pump, an oil pump, or the like is arranged between the base end step surface 2 a of the connecting shaft portion 2 and the sprocket 3.

In the above embodiments, the pulley portion 6 is made of aluminum alloy. However, it may be made of other lightweight metal such as magnesium or titanium, and further synthetic resin, ceramics, or the like. You may comprise with those composite materials.

[0020]

[Effect of device]

 According to the crankshaft pulley of the present invention, the pulley part having a large turning radius and having a large influence on the moment of inertia is made of a material having a low specific gravity, and the boss part having a small turning radius and a small influence on the moment of inertia is made of a steel material. Since it is configured, the moment of inertia of the whole can be reduced, the amplitude of torsional vibration of the crankshaft can be reduced, and since the boss part is made of steel material, sufficient strength can be secured and loosening of the fixing bolt occurs. There is no fear, and since the pulley part and the boss part are connected to each other, the structure is simple and it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mounted state of a crankshaft pulley according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a mounted state of a crankshaft pulley of a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a mounted state of a crankshaft pulley of a third embodiment of the present invention.

FIG. 4 is a sectional view of a conventional crankshaft pulley in a mounted state.

[Explanation of symbols]

 1 Crankshaft 2 Connection Shaft Part 4 Pulley 5 Boss Part 6 Pulley Part 8 Male Thread 9 Female Thread 16 Fixing Bolt 21 Flange Part 22 Mounting Plate Part 23 Coupling Bolt 25 Welding

Claims (1)

[Scope of utility model registration request] 1. A crankshaft pulley attached to one end of a crankshaft for driving an auxiliary machine or the like in an engine, fitted to one end of the crankshaft and screwed to an axial center of the one end of the crankshaft. The crankshaft pulley is characterized in that the boss portion fastened and fixed by the fixing bolts is made of a steel material, and the pulley portion is made of a material having a low specific gravity, and the boss portion and the pulley portion are joined together.