JP2000314450A - Damper device - Google Patents

Abstract

(57) [Problem] To provide a damper device for torsional vibration reduction excellent in durability and reliability. The damper device is mounted on a rotary shaft, such as a crankshaft of an engine, where torsional vibration occurs, and has a casing having a U-shaped cross section, and is liquid-tightly mounted on an open end of the casing. An annular cover, an annular inertial body housed in a closed space inside the casing and the annular cover,
In a viscous damper made of silicone oil sealed in the closed space, a large number of cooling fins are provided on the outer surface of the casing and are extended in the radial direction, separated by grooves having both ends opened in the radial direction. Each cooling fin has
On the same circumference centered on the rotation axis, a substantially circular or elliptical boss portion swelling in the groove is provided, and a balance hole for statically balancing the casing is drilled in the required boss portion. I do. The ratio W / H of the groove width W and the height H of the cooling fin in the radial center portion of the cooling fin is set to 1.0 to 2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper device mounted on a rotating shaft that generates torsional vibration, such as a crankshaft of a vehicle engine, to reduce torsional vibration.

[0002]

2. Description of the Related Art Conventionally, as a damper device mounted on a crankshaft of an engine to reduce torsional vibration, a casing fixed to a rotating shaft, rotating integrally with the rotating shaft, and having an annular groove in an outer peripheral portion; An annular cover mounted at the open end of the annular groove of the casing and forming an annular closed space in cooperation with the annular groove, and inserted into the annular closed space with a small gap between the inner wall surface thereof; In a so-called viscous damper having a high-viscosity liquid, usually silicone oil between the annular closed space and the inertial ring, a large number of radially extending outer surfaces of the casing are provided. For example, Japanese Patent Application Laid-Open No. 6-264973 discloses a damper device that is provided with cooling fins and is intended to prevent early deterioration of enclosed silicone oil due to high temperature. (Hereinafter, in some cases, the device described in the above publication is referred to as a previously proposed damper device.)

An outline of the structure of the above-mentioned proposed damper device is as follows.
Referring to the cross-sectional view of FIG. 11 and the partial front view of FIG. 12, a damper device generally indicated by reference numeral 10 includes an annular casing 12 having a U-shaped cross section, and a radially inner portion of the casing. On the peripheral wall, the casing 12
1 provided with a plurality of bolt holes 14 through which mounting bolts for coaxially fixing the shaft to an engine crankshaft are inserted.
6 are integrally formed. An annular cover 18 is fixed to the annular opening end of the casing 12 in a liquid-tight manner by fixing means such as caulking or welding. The annular closed space 20 having a substantially rectangular cross section is limited by the casing 12 and the annular cover 18.
An annular inertial body 2 made of an iron-based material such as cast iron with a small gap between the casing 12 and the inner wall surface of the annular cover 18.
2 are inserted so as to freely rotate relative to each other.

[0004] The inertial body 22 is supported in an annular closed space 20 via a bearing member 24 made of an appropriate resin material. In the small gap between the outer peripheral surface,
A highly viscous liquid, usually silicone oil, is sealed and filled. As shown in FIG. 12, a plurality of cooling fins 26 extending in the radial direction are provided on the outer surface of the casing 12, and radially outer or inner ends of the cooling fins (the former in the figure). Are connected to an annular partition wall 28, and grooves 30 are formed between the cooling fins 26 so that the cooling air flows radially outward. Further, the partition wall has a balance hole 32 for taking a static balance of the casing 12 as a rotating body.
If necessary, an appropriate number of holes are formed at appropriate positions on the circumference.

In the above-mentioned damper device, since the outer end (or inner end) of the cooling fin 26 is partitioned by the annular partition wall 28 and acts as a weir, the inside of the groove 30 is rotated by the centrifugal force when the casing 12 rotates. The flow rate of the cooling air flowing in the radial direction is small, and the number of the cooling fins 26 is small and the cooling fins 26 are arranged at an interval of 22.5 degrees with respect to the central angle, and are only 16 on the entire circumference, The width W in the circumferential direction of the groove 30 at the radial center portion of the cooling fin 26 is extremely large with respect to the height H, and the ratio W / H is approximately 4.5, which is very large. For reasons such as a small total heat exchange surface area, the casing 12
Has a small heat radiation capability, the characteristics of the encapsulated silicone oil deteriorate relatively early, and the durability and reliability of the damper device 10 are insufficient. Further, since the outer end or the inner end of the cooling fin 26 is connected by the annular partition wall 28, there is an advantage that the balance hole 32 can be formed at low cost by drilling in order to remove unbalanced weight, Since the partition wall 28 other than the portion where the balance hole 32 is provided becomes useless, the weight of the damper device 10 as a whole increases, and the vibration suppression function is deteriorated due to the increase in the useless weight.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned various problems of the above-described proposed damper device, has excellent heat radiation performance, and therefore can prevent early deterioration of a high-viscosity liquid such as silicone oil enclosed therein. It can be effectively prevented to improve durability and reliability. In addition, it is lightweight and can easily perform the balancing work required as a high-speed rotating body at low cost. It is a main object to provide a viscous damper device having excellent functions.

[0007]

SUMMARY OF THE INVENTION The present invention has been devised to achieve the above object, and comprises a casing fixed to a rotating shaft, integrally rotating with the rotating shaft, and having an annular groove in an outer peripheral portion. An annular cover attached to the open end of the annular groove of the casing and forming an annular closed space in cooperation with the annular groove;
An annular inertial body inserted into the annular space with a small gap between the inner wall surface thereof, a high-viscosity liquid sealed in a gap between the annular closed space and the inertial body, and an outer surface of the casing. And a plurality of cooling fins formed extending in the radial direction and having both inner and outer ends opened, and a plurality of cooling fins formed in the circumferential direction by the grooves. The present invention proposes a damper device characterized in that boss portions protruding in grooves are formed.

In the present invention, the boss portion of the cooling fin is disposed on the same circumference around the rotation axis, and the height of the cooling fin from the bottom of the groove is H. When the width of the groove at the radial center position of the cooling fin is W, it is preferable that W / H = 1.0 to 2.0.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be specifically described below with reference to FIGS. (Note that
The same reference numerals are used for members and portions that are substantially the same as or correspond to the already proposed damper device shown in FIGS. 11 and 12. First, in the first embodiment shown in the sectional view of FIG. 1 and the partial front view of FIG. 2, an annular closed space 20 in which the inertial body 22 is to be accommodated is formed in cooperation with the annular cover 18. A large number of cooling fins 26 extending in the radial direction are provided on the outer surface of the casing 12 to be formed, and grooves 30 are provided between the cooling fins 26 with radially open inner and outer ends. I have. The cooling fins 26 extend from the inner radius R ₁ over the outer radius R _2, the radial center position,
That is, the height H of the groove width W and the cooling fins 26 of the groove 30 on the circumference of a radius R _3, in the operating state in which the casing 12 is rotating, the grooves 30 as possible in a large amount of the cooling fluid or atmosphere A sufficiently large heat dissipation area mainly composed of the surfaces of the cooling fins 26 and the grooves 30 is ensured in which air flows, and is preferably manufactured as an aluminum alloy casting (of course, it may be made of cast iron or the like). In consideration of the manufacturing technology of the casing 12 (such as manufacturing a sound casting having no casting defects such as cavities within a reasonable cost range), the ratio of W / H is 1.0 to 2.0. Set to range.

In the region where the ratio W / H exceeds 2.0,
Insufficient cooling effect due to insufficient heat radiation area, W / H
Is less than 1.0, the arrangement pitch of the cooling fins 26 is too small with respect to the fin height H, so that a sufficient flow rate of cooling air cannot be obtained, and it is difficult to obtain a sound cast product. Is advantageous. As an example, in the illustrated embodiment, 36 cooling fins 26 are provided on the entire circumference at equal intervals of 10 degrees with respect to the central angle. However, dampers mounted on a crankshaft of a normal truck diesel engine are used. In the case of the device 10, it is appropriate that the number of the cooling fins 26 is in the range of 28 to 48 (about 12.9 degrees to 7.5 degrees as the central angle) from the viewpoint of manufacturing technology and heat radiation performance. Grooves 30 are provided near the radial outer periphery of each cooling fin 26.
A substantially circular boss portion 34 which protrudes inward and partially narrows the groove width is disposed on the same circumference around the rotation axis OO, and the boss portion is not attached to the casing 12. Drill hole 3 for static balance when equilibrium weight is present
2 are drilled as needed.

FIG. 3 is a partial front view similar to FIG. 2, showing a casing 12 of a damper device 10 showing a second embodiment of the present invention. In this embodiment, except for the point that the boss portion 34 provided on the cooling fin 26 and bulging into the groove 30 is formed in a shape of an elliptical shape in the radial direction, other configurations are the same as those of the first embodiment. Is substantially the same as FIG. 4 is a partial front view of a casing 12 showing a third embodiment of the present invention. In this embodiment, the cooling fins 26
Boss portion 34 substantially forms a circular provided is that it is located slightly inward from the central portion, that the radius R ₃ radial length of the cooling fins 26 is present in the first embodiment, other The configuration is substantially the same as that of the first embodiment. The second
In both the third embodiment and the third embodiment, the boss portions 34 are arranged on the same circumference around the rotation axis OO, and are provided so that the boss portions 34 themselves do not form an unbalanced weight.

A plurality of cooling fins 26 extending in the radial direction are provided on the outer surface of the casing 12 in common with the first, second and third embodiments, and grooves 30 formed between the cooling fins 26 are provided. However, since the respective radially inner and outer ends are opened to form a continuous passage in the radial direction, the radially outer end portion or the inner portion of the cooling fin is formed as in the above-described damper device. Compared to the case where the partition wall connecting the end portions is provided, the flow rate of air flowing radially outward in the groove 30 due to the centrifugal force accompanying the rotation of the casing 12 is increased, and the cooling fin 26 is provided in the groove 30. The boss portion 34 is provided on the boss portion 34, and the shape of the passage of the groove 30 changes at the portion of the boss portion 34, so that a vigorous vortex that is favorable for heat transfer is generated. H
By setting the width W of the groove 30 at the radial center of the cooling fin in the range of W / H = 1.0 to 2.0, excellent heat radiation performance can be obtained.

FIG. 5 shows that the heat transfer coefficient of the damper device 10 when the cooling fin 26 is not provided on the outer surface of the casing 12 is α _0, and the heat transfer coefficient when the cooling fin 26 is provided is α
Α / α ₀ is plotted on the vertical axis, and the cooling fins 26 are plotted on the horizontal axis.
FIG. 5 is a diagram showing the relationship between the width W of the groove 30 and the height H of the fin at the center in the radial direction W / H. Curve _{X 1} indicated by the solid line in the figure shows the damper device of the first embodiment, while an α / α ₀ = 1.45~1.65, curve _{X 2} indicated by a dotted line in the figure As shown in FIG.
The outer peripheral portion of the show the case in which the partition wall 28, α / α ₀
= 1.15 to 1.3, and it is clear that the heat transfer coefficient of the damper device of the first embodiment is significantly improved over the damper device of the previously proposed damper device. Further, it is clear that the heat transfer coefficient is excellent in the region where the W / H is 1.0 to 2.0 in any of the curves X ₁ and X ₂ . Note that α / α ₀ of the damper device 10 according to the second and third embodiments is substantially equivalent to that of the first embodiment, and in the damper device already proposed, the inner end of the cooling fin 26 has an annular shape. When connected by a partition wall, α / α ₀ was found to be located between the curves X ₁ and X ₂ .

FIG. 6 shows the relationship between the number of cooling fins 26 and the temperature rise ΔT of the damper device in the first to third embodiments mounted on the crankshaft of the diesel engine for trucks. 9 shows a result of an investigation on a damper device. As shown by the curve Y in the figure,
When the number of cooling fins 26 is small and the heat radiation area is small, the amount of temperature rise is large. When the number of fins is in the range of 28 to 48, the amount of temperature rise is sufficiently low. Since the heat radiation effect of the increase in number becomes substantially constant, the casting mold of the casing 12 becomes complicated,
Considering the deterioration of casting quality, the number of cooling fins is 28 to 4
Eight ranges have been found to be advantageous.

In the damper device 10 of this type, the inertia body 22 is accommodated in the closed space 20 and silicon oil is sealed therein. When torsional vibration occurs, the inertia body 22 is not accompanied by shear deformation of the silicon oil. While casing 12
By rotating relative to the annular cover 18, the torsional vibration is reduced. At this time, the vibration energy absorbed by the silicon oil is converted into heat, and the heat is mainly transferred to the casing 12, the cooling fins 26, and the annular cover 18.
Therefore, the viscosity characteristics of the silicone oil and the viscosity change characteristics during long-term operation are important because the oil is radiated from the surface to the outside air.
Therefore, in the damper device 10 shown in the first to third embodiments, the viscosity is preferably 300,000 cst ± 10%.
(At 25 ° C.), dynamic shear modulus G ′ = 0.16 to 0.2 kgf / cm ² (related to the spring constant _Kd of the damper device), which is important for the vibration damping function, and dynamic viscosity coefficient μ. '=
(1.5-1.9) × 10 ⁻⁴ kgf. Preferably, silicone oil of s / cm ² (related to the damping coefficient C _d of the damper device) is used.

FIG. 7 shows a damper device, for example, FIGS.
2 shows the relationship between the viscosity of the silicone oil enclosed in the damper device 10 and the damper temperature rise ΔT (the average temperature rise of the casing 12 and the annular cover 18). As shown, the viscosity is 100,000 cst (at 25
° C) silicone oil has the largest temperature rise,
The temperature rise near cst (at 25 ° C) is the smallest,
In the case of 600,000 cst (at 25 ° C.) silicone oil, the amount of temperature rise shows a tendency to rise again. Accordingly, the silicone oil sealed in the damper device 10 is 300,000 cs.
The one having a viscosity of t ± 10% (at 25 ° C.) is optimal.
The results of examining the relationship between the dynamic shear modulus G ′ and the dynamic viscosity coefficient μ ′, which greatly affect the function of reducing the torsional vibration of the silicone oil sealed in the damper device 10, and the temperature of the silicone oil are shown in FIG. 8 and FIG. Silicone oil in the figure the curve _{S 1} in dotted lines 100,000 cst (at25 ℃), the solid curve _{S 2} 300,000 cst (AT25
Silicone oil ° C.), the curve _{S 3} of the dashed line 600,000 c
The silicon oil at st (at 25 ° C.) is shown. As shown in the above figures, 300,000 cst (at 25 ° C.) silicon oil exhibits the most stable characteristics in the entire region of the silicon oil temperature of 40 to 160 ° C. when the damper device 10 is in operation, Shear modulus G '= 0.
16-0.2 kgf / cm ² , dynamic viscosity coefficient μ ′ = 1.
5 to 1.9 × 10 ⁻⁴ kgf. s / cm ² is found to be an advantageous numerical range. Further, in FIG. 10, the vertical axis indicates the viscosity ratio of the silicone oil (the viscosity of the new silicone oil is assumed to be 100%), and the horizontal axis indicates the silicon oil temperature (that is, the ambient temperature + the temperature rise amount). The effect of temperature on the decrease in silicone oil viscosity was investigated. Dotted line in the figure is an allowable level of viscosity reduction of the silicone oil required in order to suppress the change in durability before and after the torsional vibration, the damper device 10 which points Z ₁ on the curve Z is according to the first embodiment It indicates the point Z ₂ denotes a damper device having no cooling fins. As shown in the figure, in the damper device 10 according to the first embodiment, since the viscosity at or above the allowable level is maintained even near the maximum temperature of the silicon oil during operation, there is little change in the effect of reducing the torsional vibration and the advantage of high stability. There is. Note that substantially the same results were obtained with the damper devices 10 according to the second and third embodiments.

[0017]

As described above, the damper device according to the present invention comprises a casing fixed to a rotating shaft and integrally rotating with the rotating shaft and provided with an annular groove in an outer peripheral portion; An annular cover attached to the open end and forming an annular closed space in cooperation with the annular groove, and an annular inertial body inserted with a small gap between its inner wall surface in the annular space, A high-viscosity liquid sealed in a gap between the annular closed space and the inertial body, a plurality of grooves formed on the outer surface of the casing so as to extend in the radial direction, and having both inner and outer ends opened, and A plurality of cooling fins formed at intervals in the circumferential direction, wherein each of the cooling fins is formed with a boss portion swelling in the groove, and silicon sealed during the vibration damping operation. Excellent heat dissipation performance to dissipate heat of high viscosity liquids such as oil to the outside air It is possible to effectively prevent the early deterioration of silicon oil etc. and improve the durability and reliability of the damper device. Furthermore, it is possible to balance the casing easily and at low cost with light weight, and to reduce waste weight. There is an advantage that it is possible to provide a damper device with a small vibration damping function. In the present invention, the boss portion of the cooling fin is disposed on the same circumference around the rotation axis, and the height of the cooling fin from the bottom surface of the groove is H, and Assuming that the width of the groove at the radial center position of the cooling fin is W, by setting W / H = 1.0 to 2.0, there is an advantage that the heat radiation performance of the casing can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a partial front view as viewed from the direction of arrow II in FIG. 1;

FIG. 3 is a partial front view similar to FIG. 2, showing a second embodiment of the present invention.

FIG. 4 is a partial front view similar to FIG. 3, showing a third embodiment of the present invention.

FIG. 5 is a diagram showing the effect of the ratio of the width of the groove between the cooling fins to the height of the fins on the heat transfer coefficient in the present invention, in comparison with a damper device already proposed.

FIG. 6 is a diagram showing the relationship between the number of cooling fins and the amount of increase in the damper temperature in the present invention.

FIG. 7 is a diagram showing a relationship between a damper temperature rise amount and a viscosity of silicone oil sealed in the present invention.

FIG. 8 is a diagram showing the relationship between the dynamic shear modulus of silicone oil and the temperature of silicone oil.

FIG. 9 is a diagram showing a relationship between a dynamic viscosity coefficient of silicon oil and a silicon oil temperature.

FIG. 10 is a diagram showing a relationship between a silicone oil viscosity ratio and a silicone oil temperature.

FIG. 11 is a sectional view showing a damper device already proposed.

FIG. 12 is a partial front view as viewed from the direction of arrow XII in FIG. 11;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Damper apparatus, 12 ... Casing, 14 ... Bolt hole, 16 ... Flange part, 18 ... Circular cover, 20 ... Circular closed space, 22 ... Inertial body, 26 ... Cooling fin, 30 ...
Groove, 32: Balance hole, 34: Boss

Claims (2)

[Claims] A casing fixed to a rotating shaft and integrally rotating with the rotating shaft and provided with an annular groove in an outer peripheral portion; an annular ring mounted on an open end of the annular groove of the casing and cooperating with the annular groove. An annular cover forming an enclosed space, an annular inertial body inserted with a small gap between the inner wall surface of the annular space, and an annular inertial body sealed in the gap between the annular closed space and the inertial body. A plurality of high-viscosity liquids, a plurality of grooves formed on the outer surface of the casing, each extending in the radial direction, and a plurality of cooling fins formed in the circumferential direction and separated by the grooves; Wherein each of the cooling fins has a boss portion bulging into the groove. 2. The boss portion of the cooling fin is disposed on the same circumference around the axis of the rotation axis, the height of the cooling fin from the bottom surface of the groove is H, and 2. The damper device according to claim 1, wherein W / H = 1.0 to 2.0, where W is the width of the groove at the radial center position of the cooling fin. 3.