JPS6314128Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a crank pulley that reduces vibration and noise emitted from the crank pulley of an engine.

Vibration and noise, which affect the quality of automobiles, especially their comfort, must be kept as low as possible. This idea is
In particular, the purpose is to reduce vibration noise from the engine, which is the largest source, such as vibration noise generated by transmission through the crank pulley.

First, the generation of vibration noise from a conventional crank pulley will be explained with reference to FIGS. 1 and 2.

In FIG. 1, 1 is a crankshaft, and 2 is a main journal supported by a bearing portion of a cylinder block. 3 is a crank arm, 4 is a crank pin, and the large end of the connecting rod is attached here. 5 is a balance weight for canceling a part of the centrifugal force of the crank arm 3 and crank pin 4. 6
A crank pulley is attached to the tip of the crankshaft 1, and drives an alternator, water pump, etc. with a fan belt (not shown). Note that a flywheel (not shown) is connected to the other end of the crankshaft 7.

In such conventional crank pulleys, the crank pulley 6 itself was a single membrane surface, so when the crank pin 4 was at the top dead center (or bottom dead center), the crankshaft 1 could move up and down. It was vibrating in the direction, causing coupled vibration with the crankshaft 1. FIG. 2 schematically shows this situation. That is, the crankshaft 1 is connected to the crank pin 4
When it is at the top dead center (or bottom dead center) position, it tends to vibrate in the vertical direction, and the crank pulley 6 is shaken by this, causing vibration. As a result, the crank pulley 6 reduces the frequency that is dominant in engine noise (1200
The problem was that they emitted high-level noise (around Hz).

This idea was created by focusing on these conventional problems, and when the crank pin is at the top dead center (or bottom dead center) position, the inertia that is balanced between the top and bottom of the crank pulley. The purpose is to solve the above problems by adding mass.

This invention will be explained below based on the drawings.

FIG. 3 is a diagram showing an embodiment of this invention.
First, to explain the configuration, 1 and 6 are the crankshaft and crank pulley, respectively, 7 is the inertial mass,
In other words, it is a weight, and it is fixed with a bolt 8 to a predetermined position on the outer peripheral end surface of the back side of the crank pulley 6, that is, the top dead center (or bottom dead center) of the crank pin 4.
are attached to the outer peripheral end surfaces of the upper and lower ends of the crank pulley 6. Therefore, in the case of 6 cylinders, a total of 6 pieces can be attached, and in the case of 4 cylinders, a total of 2 pieces can be attached. Of course, the weight 7 is attached after ensuring dynamic balance. Although the weight 7 shown in FIG. 3 has an arcuate shape, it may have any other suitable shape.

FIG. 4 is a sectional view showing a state in which the weight 7 is attached with a bolt 8. In addition, the weight 7 may be attached by welding or the like, as shown in FIG.

In any case, weight 7 is crank pulley 6
It is best to install it as far away from the center as possible to increase the moment of inertia.

Next, the effect will be explained.

The crankshaft 1 is coupled to the vibration in the vertical direction (in the plane including the crank pin 4 shown in FIG. 2) at the top dead center (or bottom dead center) position of the crank pin 4, and the crank pulley 6 is Even if the crank pulley 6 vibrates, the vibration of the crank pulley 6 itself is reduced by the inertial force of the weights 7 at the upper and lower ends of the crank pulley 6. This situation is shown in FIG. Therefore, the noise in the dominant frequency range of the engine noise radiated from the crank pulley 6 is significantly reduced.

7a and 7b show another example of attaching the weight 7, in which the weight (inertial mass) portion 10 is effectively mounted on the front and rear recesses of the V-belt groove of the crank pulley 6.
a and 10b are provided integrally. This has the advantage of extremely high productivity.

As explained above, this idea is based on the crank pin at the positions corresponding to the top dead center and bottom dead center of the crank pin.
Since the structure is such that an inertial mass is added to each pulley's outer peripheral end surface, the vibration of the crank pulley that is coupled with the vibration in the vertical direction of the crankshaft (in the plane containing the crank pin as shown in Figure 2) is reduced. is significantly reduced by the inertial force of the inertial mass, resulting in the effect that the resulting noise can also be significantly reduced.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing the conventional crank pulley and crankshaft assembly state, Figure 2 is a diagram showing the coupled vibration of the crankshaft and crank pulley, which has been a problem in the past, and Figure 3 is a diagram showing this problem. FIG. 4 is a partial sectional view of the weight shown in FIG. 3 attached, FIG. 5 is a partial sectional view showing another example of how the weight is attached, and FIG. Figures 7a and 7b, which are diagrams for explaining the effects of the invention, are a partial side sectional view and a partial front view showing still another example of mounting the weight of this invention. In the figure, 1 is a crankshaft, 2 is a main journal, 4 is a crank pin, 6 is a crank pulley, 7 is a weight, and 8 is a bolt.

Claims (1)

[Scope of utility model registration request] In a crank pulley attached to the tip of the crankshaft of a reciprocating engine, there is inertia at a position corresponding to the top dead center and bottom dead center of the crank pin of the crankshaft, and around the circumference of the outer peripheral end surface of the crank pulley. A crank pulley characterized by having different masses.