JPH054592Y2 - - Google Patents

Description

[Detailed description of the invention] "Field of industrial application" The present invention relates to a torsional damper that is attached to the tip of the crankshaft of an internal combustion engine to alleviate torsional vibration of the crankshaft, and in particular relates to a torsional damper that is attached to the tip of the crankshaft of an internal combustion engine to alleviate torsional vibration of the crankshaft. The heat resistance or aging resistance of the elastic body provided between the two is improved.

"Prior Art" Generally, a torsional damper installed in an internal combustion engine has a disc weight attached to a plate attached to the crankshaft via an elastic body.
By converting the torsional vibration of the crankshaft into internal heat generation in the elastic body, the torsional vibration is alleviated. The exposed portions of the elastic bodies used in torsional dampers are vulnerable to ozone and are susceptible to thermal deterioration due to high temperature atmospheres and radiant heat. Therefore, in order to prevent thermal deterioration, it is known that a thin heat-resistant protective rubber layer is applied to the outer periphery of the elastic body (Utility Model Publication No. 45644/1983).

``Problems to be Solved by the Invention'' Recently, there has been a trend in automobiles to increase their output or make their engine rooms smaller, and the parts where torsional dampers are installed are more likely to become hot. In the elastic body applied to a conventional torsional damper, the surface that joins the torsional plate and the disc weight is not exposed to the outside, but the inner and outer peripheral edge portions of the elastic body are exposed.

For this reason, the elastic body of the torsional damper in a high-temperature atmosphere becomes hot, and the parts exposed to the outside are exposed to radiant heat and undergo thermal deterioration.Especially, the outer peripheral edge of the elastic body, which has a high peripheral speed when the torsional damper rotates, There were problems such as high temperatures, which affected the vibration relaxation characteristics and accelerated thermal deterioration.

Conventionally, there are devices in which a heat-resistant protective rubber layer is attached to the outer periphery of the elastic body, but in that case, the protective rubber layer is thin and cannot sufficiently prevent heat transfer to the elastic body. Even if the outer periphery of the elastic body was covered with a protective rubber layer, thermal deterioration of the outer periphery of the elastic body could not be prevented.

Therefore, the present invention makes it difficult for the high temperature near the engine to be transmitted to the outer circumference of the elastic body of the torsional damper, prevents radiant heat from hitting the outer circumference of the elastic body, maintains vibration damping of the elastic body, and prevents thermal deterioration. The purpose is to prevent.

``Means for Solving the Problems'' The present invention achieves the above object in a torsional damper in which a disk weight is superimposed on the surface of a disk-shaped plate attached to the crankshaft of an internal combustion engine via an elastic body. This has been achieved.
Therefore, an annular cover with a U-shaped cross section is made of heat-resistant rubber or synthetic resin, and the U-shaped cross section of the annular cover covers the entire outer peripheral edge of the torsional damper. Both ends were fixed to a disc weight or a disc-shaped plate.

"Operation" The torsional damper of the above means is attached to the crankshaft of an internal combustion engine, and is adapted to rotate together with the driving of the internal combustion engine. During this rotation, the torsional vibration of the crankshaft is alleviated by the elastic body and disc weight. In addition, the outer peripheral edge of the torsional damper is covered with a U-shaped cross section of an annular cover made of rubber or synthetic resin, so high temperatures are difficult to be transmitted to that part, and radiant heat is blocked.
The relaxation properties of the elastic body are not affected and thermal deterioration is also prevented.

Furthermore, even if the damper is of a type in which two disc weights are provided, the annular cover that covers the outer periphery of the damper can be elastically deformed, so that the relaxation characteristics provided by both disc weights are not impaired.

"Example" An example in which the present invention is applied to a two-layer damper will be described.

The disc-shaped plate 1 of the torsional damper is
It is designed to be attached to the crankshaft K of an internal combustion engine by passing a bolt through the through hole 1a, and an annular disc weight is attached to the plate 1 through elastic bodies 2 and 2' formed in an annular shape from rubber, synthetic resin, etc. on both sides of the plate 1. 3 and 3' are attached. When the torsional damper rotates, the elastic bodies 2 and 2' convert the vibration energy of the crankshaft K into thermal energy to provide a relaxing effect.

In the case of this embodiment, the elastic bodies 2, 2' are formed to gradually become thicker toward the outside in the radial direction, so that the strain rate of the elastic bodies becomes uniform over the entire range. Further, the outer surfaces of the disc weights 3, 3' are made perpendicular to the axial direction of the crankshaft so that the rotation space of the torsional damper does not become large.

The entire outer periphery of the torsional damper is covered with an annular cover 4 made of heat-resistant rubber or synthetic resin to prevent radiant heat from hitting the outer periphery of the elastic bodies 2, 2'. As shown, an air layer is interposed between the inner surface of the annular cover and the elastic bodies 2, 2'. The outer periphery of the annular cover 4 has a U-shaped cross section, and an annular protrusion 4a is provided on the inner wall at both ends.
is provided, and this protrusion 4a is engaged with an annular groove 5 provided on the outer surface of each disc weight 3, 3'.
An annular cover 4 is fixed.

Note that the annular cover 4 is the disk weight 3, 3'.
It is preferable to limit the portion covering the outer surface of the torsional damper to a portion as close to the outer peripheral edge of the torsional damper as possible so that the heat generated by the elasticity 2, 2' can be dissipated. Further, as a method of fixing the annular cover 4, a plurality of protrusions may be provided instead of the annular protrusion 4a, and holes for engaging the protrusions may be provided on the outer surface of the disc weights 3, 3', or by adhesive bonding, It may also be secured with screws, etc.

The inner periphery of the annular elastic body 2, 2' has a lower circumferential speed than the outer periphery and is less exposed to radiant heat, so the inner periphery is less susceptible to aging than the outer periphery. Therefore, even if the annular cover 4 is provided only on the outer peripheral edge of the elastic bodies 2, 2', durability can be considerably increased.
The inner circumferential edge of 2' may be covered with a cover in the same manner as described above. In that case, the elastic body 2,
2' is covered, and its both ends are fixed to the disc weights 3, 3' and the plate 1 to prevent radiant heat etc. from hitting the inner peripheral edge.

In the above embodiment, a two-layer damper has been described, but the heat-resistant annular cover 4 can be applied to a single-layer damper as well. In that case, the annular cover 4
Both ends of the U-shaped section are fixed to the disc weight 3 and the disc-shaped plate 1.

``Effects of the invention'' In this invention, the exposed part of the elastic body used in the torsional damper is covered with an annular cover made of heat-resistant rubber, etc., so high-temperature heat is difficult to be transmitted to the outer periphery of the elastic body, and radiant heat is can be prevented from hitting the outer periphery of the elastic body. Therefore, the torsional vibration relaxation characteristics of the elastic body are less likely to be impaired, and thermal deterioration is also less likely to occur.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the torsional damper of the present invention, and FIG. 2 is a front view of the torsional damper. 1... Plate, 2... Elastic body, 3... Disk weight, 4... Annular cover.

Claims (1)

[Scope of utility model registration request] In a torsional damper, in which disc weights are stacked and mounted on the surface of a disc-shaped plate attached to the crankshaft of an internal combustion engine, via an elastic body, an annular cover whose outer periphery is U-shaped in cross section is made of heat-resistant rubber or synthetic resin. The torsion is characterized in that the annular cover has a U-shaped cross section that covers the entire outer peripheral edge of the torsional damper, and both ends of the U-shaped cross section of the annular cover are fixed to a disc weight or a disc-shaped plate. Yonal damper.