JP7377696B2 - torsional damper - Google Patents

Description

The present invention relates to a torsional damper.

A torsional damper (hereinafter also referred to as TVD) is attached to the tip of the crankshaft and has the function of reducing torsional vibration of the crankshaft through the action of a rubber ring fitted between the hub and the vibration ring (mass). It is a product that provides
In addition, the TVD may also function as a crank pulley that transmits power to auxiliary equipment (alternator, air conditioner, water pump) via a belt.

When the torsional vibration of the crankshaft approaches or exceeds the resonance range, relative vibration occurs in the torsional direction between the hub of the TVD and the vibration ring, and the rubber ring of the TVD generates heat. As a result, if the temperature exceeds the heat resistance temperature of the rubber ring, the rubber ring may be damaged.

As a conventional method related to this, for example, the method described in Patent Document 1 can be mentioned.
Patent Document 1 discloses a torsional damper that includes a damper hub that is attached to a rotating shaft and rotates integrally with the rotating shaft, and an inertia ring that is attached to the damper hub via a rubber member, The member is made of a rubber composition containing EPDM as a main component, and the rubber member installed between the damper hub and the inertia ring has a loss coefficient (tan δpi) of 0 when the surface temperature is 60±5°C. .27 or higher, and the maximum surface temperature (Tmax) of the rubber member during continuous vibration at the resonance point of the torsional damper is expressed by the following formula: Tmax=α×ln(tanδpi)+β≦100 (in the formula , α represents a coefficient in the range of −46.9 to −60.4, and β represents a coefficient in the range of +9.4 to +27.7). It also states that such a torsional damper can suppress the temperature rise of the rubber member installed between the damper hub and the inertia ring, so it is possible to provide a torsional damper with improved durability. has been done.

JP2018-96455A

However, even with the torsional damper described in Patent Document 1, the temperature of the rubber ring may rise due to heat generation depending on its structure.

The present invention aims to solve the above problems. That is, an object of the present invention is to provide a torsional damper having a structure in which the rubber ring is extremely unlikely to be damaged due to heat generation.

The present inventor focused on the structure of a torsional damper on the premise that heat generation is unavoidable as a result of thermal energy being applied to a TVD. We then conducted extensive research into the structure of a torsional damper that would prevent the temperature of the rubber ring from rising even when it generated heat.
As a result, they discovered that a torsional damper with a specific structure makes it difficult for the temperature of the rubber ring to rise, and the present invention was completed.

The present invention includes the following (i) to (iv).
(i) a hub fixed to a rotating shaft and having an outer peripheral surface on a circumference centered on the rotating shaft;
an annular vibration ring having an inner peripheral surface having a diameter larger than the outer peripheral surface of the hub on a circumference centered on the rotation axis;
The loss coefficient ( a rubber ring whose tan δ) is 0.18 or more;
Equipped with
When subjected to the resonance point tracking method, the maximum temperature (Tmax) reached at the surface of the rubber ring during continuous vibration at the resonance point and the wall thickness (e) of the hub fitting part are:
Formula (1): Tmax≦-7.3e+141.1
Formula (2): 2.9≦e
A torsional damper that satisfies the following.
(ii) When subjected to the resonance point tracking method, the maximum temperature (Tmax) reached at the surface of the rubber ring during continuous vibration at the resonance point and the wall thickness (e) of the hub fitting part are:
moreover,
Formula (3): Tmax≧-30.0e+195.0
The torsional damper described in (i) above, which satisfies the following.
(iii) When subjected to the resonance point tracking method, the maximum temperature (Tmax) reached at the surface of the rubber ring during continuous vibration at the resonance point and the wall thickness (e) of the hub fitting part are:
moreover,
Formula (4): Tmax≧20e-30.0
The torsional damper described in (i) or (ii) above, which satisfies the following.
(iv) The above formula (2) is formula (2'): 2.9≦e≦8
The torsional damper according to any one of (i) to (iii) above, which satisfies the following.

According to the present invention, it is possible to provide a torsional damper having a structure in which the rubber ring is extremely unlikely to be damaged due to heat generation.

1 is a schematic perspective view illustrating an embodiment of a torsional damper of the present invention. FIG. 2 is a schematic cross-sectional perspective view of the torsional damper shown in FIG. 1. FIG. FIG. 2 is a schematic cross-sectional perspective view for explaining a method of manufacturing the torsional damper shown in FIG. 1. FIG. FIG. 2 is a schematic cross-sectional perspective view of a torsional damper subjected to a resonance point tracking method. It is a graph showing an example of the surface temperature of a rubber ring when a resonance point tracking method is performed. It is a graph showing the relationship between the hub fitting portion wall thickness (mm) and the maximum temperature reached at the rubber ring surface (Tmax).

<Example of torsional damper>
The present invention will be explained.
The present invention provides a hub that is fixed to a rotating shaft and has an outer peripheral surface on a circumference centered on the rotating shaft, and a hub that has a diameter larger than the outer peripheral surface of the hub on the circumferential surface centered on the rotating shaft an annular vibrating ring having an inner circumferential surface; the rubber composition is present in a compressed state between the outer circumferential surface of the hub and the inner circumferential surface of the vibrating ring; the rubber composition has EPDM as a main component; a rubber ring having a loss coefficient (tan δ) of 0.18 or more when Torsional where the maximum surface temperature (Tmax) and the wall thickness of the hub fitting part (e) satisfy formula (1): Tmax≦-7.3e+141.1, formula (2): 2.9≦e It is a damper.
Such a torsional damper is also referred to below as "the torsional damper of the present invention".

First, the torsional damper of the present invention will be explained using FIGS. 1 and 2.
FIG. 1 is a schematic perspective view illustrating an embodiment of the torsion damper of the present invention, and FIG. 2 is a schematic cross-sectional perspective view of the torsion damper shown in FIG.

The torsional damper 1 of the embodiment illustrated in FIGS. 1 and 2 can be used by being attached to the tip of the crankshaft of an engine of a vehicle or the like. The torsional damper 1 has the function of absorbing torsional resonance of the crankshaft and suppressing engine vibration and noise. Furthermore, it may also serve as a drive pulley (crank pulley) that transmits power from the rotation of the crankshaft to auxiliary equipment via a belt.

The torsional damper 1 includes a hub 3, a vibration ring 5, and a rubber ring 7.

The hub 3 includes a boss portion 31, a stay portion 33, and a rim portion 35.
The boss portion 31 is provided at the center of the hub 3 in the radial direction. The boss portion 31 is fixed to the tip of a crankshaft (rotating shaft), and the hub 3 is driven to rotate around the rotating shaft X.
The stay portion 33 extends from the boss portion 31 in the radial direction.
The rim portion 35 is provided on the outer peripheral side of the stay portion 33. The rim portion 35 has a cylindrical shape, and the vibration ring 5 is connected to the outer peripheral side of the rim portion 35 via a rubber ring 7.
The outer peripheral surface of the rim portion 35 exists on a circumference centered on the rotation axis X.

Each of the boss portion 31, the stay portion 33, and the rim portion 35 can be formed using a metal material such as cast iron as a raw material.
In addition, each of the boss portion 31, the stay portion 33, and the rim portion 35 is preferably made of flake graphite cast iron, spheroidal graphite cast iron, hot rolled steel plate for automobile structures, or the like. Examples of flake graphite cast iron include FC100, FC150, FC200, FC250, FC300, FC350, and the like. Examples of spheroidal graphite cast iron include FCD350-22, FCD350-22L, FCD400-18, FCD400-18L, FCD400-15, FCD450-10, FCD500-7, FCD600-3, FCD700-2, FCD800-2, FCD400- 18A, FCD400-18AL, FCD400-15A, FCD500-7A, FCD600-3A, etc. Examples of rolled steel plates for automobile structures include SAPH310, SAPH370, SAPH410, SAPH440, and the like.

The vibration ring 5 is arranged radially outward of the hub 3. The inner peripheral surface of the vibration ring 5 has a larger diameter than the outer peripheral surface of the hub 3. This inner circumferential surface exists on a circumference centered on the crankshaft (rotation axis X).
Further, a pulley groove 51 on which a belt is applied is provided on the outer peripheral surface of the vibrating ring 5. The pulley groove 51 functions as a pulley for power transmission.

The vibration ring 5 can be molded using a metal material such as cast iron as a raw material.
Moreover, it is preferable that the vibration ring 5 is made of flaky graphite cast iron. This is because flake graphite cast iron has an excellent ability to absorb vibrations and also has excellent wear resistance. Examples of flake graphite cast iron include FC100, FC150, FC200, FC250, FC300, FC350, and the like.

The rubber ring 7 is inserted into the gap between the outer peripheral surface of the hub 3 and the inner peripheral surface of the vibration ring 5. The rubber ring 7 plays the role of reducing torsional vibration of the crankshaft that occurs while the vehicle is running, thereby preventing damage, and reducing noise and vibration caused by engine vibration.

The rubber ring 7 is made by vulcanizing and molding a rubber composition mainly composed of ethylene-propylene-diene ternary copolymer (EPDM) and preferably containing carbon black and process oil into a cylindrical shape or the like by a conventionally known method. You can get it by doing
The rubber composition preferably contains EPDM in an amount of 10 to 60% by mass or more, more preferably 15 to 55% by mass, more preferably 20 to 50% by mass, and even more preferably 30 to 50% by mass. preferable.
Further, carbon black is preferably used in an amount of 40 to 130 parts by weight, more preferably 50 to 100 parts by weight, and even more preferably 60 to 80 parts by weight based on 100 parts by weight of EPDM.
Here, the rubber composition may contain zinc white, stearic acid, an anti-aging agent, a peroxide, a crosslinking agent, and the like.

The rubber ring 7 has a loss coefficient (tan δ) of 0.18 or more, preferably 0.18 to 0.40, and preferably 0.19 to 0.35 when the surface temperature is 60 ± 5 ° C. It is more preferably 0.20 to 0.28.

Here, the loss coefficient (tan δ) when the surface temperature is 60±5° C. means a value obtained by measurement by a resonance point tracking method (natural frequency measurement) using a high frequency vibration tester. Note that measurements using the resonance point tracking method shall be performed under the following conditions.
・Excitation amplitude: ±0.05deg
・Phase during excitation: -90deg
・Ambient temperature: 23±3℃
・Rubber surface measurement method: Non-contact surface thermometer

<Manufacturing method>
The method of manufacturing such a torsional damper of the present invention is not particularly limited.
For example, it can be manufactured by the following method.
First, a hub 30 and a vibration ring 50 as shown in FIG. 3 are prepared, and a torque improving liquid is applied thereto by means such as spraying. As the torque improving liquid, a solution in which a silane coupling agent is mainly dissolved in a hydrocarbon solution (solvent) such as toluene or xylene can be used. It is preferable that the torque improving liquid be applied to the parts of the hub 30 and the vibration ring 50 that come into contact with the rubber ring 70, that is, the inner peripheral surface of the vibration ring 50 and the outer peripheral surface of the rim portion of the hub 30.
Then, as shown in FIG. 3, a rubber ring coated with a fitting liquid is press-fitted into the gap (gap portion 80) between the hub 30 and the vibration ring 50 using a press-fitting jig such as a press machine. Here, it is preferable that the width of the gap 80 is narrower than the thickness of the rubber ring 70. Specifically, the thickness of the rubber ring 70/width of the gap 80 is preferably about 0.6 to 0.9.
In the torsional damper of the present invention, the rubber ring exists in a compressed state between the outer peripheral surface of the hub and the inner peripheral surface of the vibration ring.

<Study of the structure of the torsional damper that affects the temperature of the rubber ring>
The present inventor has developed various torsional structures with different vibrating ring wall thicknesses (a), fitting widths (b), rubber thicknesses (c), fitting diameters (d), and hub fitting portion wall thicknesses (e). We prepared a damper and examined its effect on the temperature of the rubber ring.

Here, the vibration ring wall thickness (a) means the thickness of the vibration ring 5 in the radial direction (direction perpendicular to the rotation axis X), as shown in FIG. As in the embodiment shown in FIG. 2, when the vibration ring wall thickness (a) is not constant in the radial direction of the vibration ring 5, the thickness in the radial direction of the vibration ring 5 is measured at 10 randomly selected points. , and the value obtained by averaging them is defined as the vibration ring wall thickness (a).

As shown in FIG. 4, the fitting width (b) means the length of the rim portion 35 of the hub 3 in the direction of the rotation axis X. When the fitting width (b) is not constant in the rotation axis X direction, the length of the longest part of the rim portion 35 of the hub 3 in the rotation axis X direction is defined as the fitting width (b).

As shown in FIG. 4, the rubber thickness (c) means the thickness of the rubber ring 7 in the radial direction (direction perpendicular to the rotation axis X). As in the embodiment shown in FIG. 2, when the rubber thickness (c) is not constant in the radial direction of the rubber ring 7, the thickness in the radial direction of the rubber ring 7 is measured at ten randomly selected points, and The value obtained by averaging the values is defined as the rubber thickness (c).

The fitting diameter (d) means the diameter of the outer peripheral surface of the rim portion 35 in the hub 3, as shown in FIG. Moreover, the fitting diameter (d) shall mean the shortest diameter among the diameters (outer diameters) of the outer peripheral surface of the rim portion 35. Therefore, when the rim portion 35 meanders in the direction of the rotation axis X as in the embodiment shown in FIG. 2, the point closest to the rotation axis shall mean the diameter at the center point in the direction).

The hub fitting portion wall thickness (e) means the thickness of the rim portion 35 of the hub 3 in the radial direction (direction perpendicular to the rotation axis X), as shown in FIG. Here, the hub fitting portion wall thickness (e) means the thickness of the portion of the rim portion 35 other than the portion connected to the stay portion 33. In addition, as in the embodiment shown in FIG. 2, when the hub fitting part wall thickness (e) is not constant in the direction perpendicular to the rotation axis The thickness of the rim portion 35 in the radial direction (excluding the portion connected to the stay portion 33) at the point is measured, and the value obtained by averaging these values is defined as the hub fitting portion wall thickness (e).

The present inventor has developed the embodiment shown in FIG. Torsional dampers having various structures with different e) were prepared, each torsional damper was subjected to the resonance point tracking method described above, and the maximum temperature (Tmax) reached at the surface of the rubber ring at that time was measured. Note that the measurement of the maximum surface temperature (Tmax) of the rubber ring using the resonance point tracking method shall be performed under the following conditions.
・Excitation amplitude: ±0.05deg
・Phase during excitation: -90deg
・Test time: Until the surface temperature of the rubber ring reaches saturation ・Ambient temperature: 23±3℃
・Rubber surface measurement method: Non-contact surface thermometer

While performing such a resonance point tracking method, the surface temperature of the rubber ring of the torsional damper was measured using a non-contact surface thermometer.
An example of the measurement results is shown in FIG.
As shown in FIG. 5, the surface temperature of the rubber ring (vertical axis in FIG. 5) gradually increases from the start of the test, and saturates after about 30 minutes.
The surface temperature of the rubber ring at the time of saturation was defined as the maximum temperature (Tmax) reached by the surface of the rubber ring in the torsional damper having that structure.

As described above, the present inventor has determined that the vibration ring wall thickness (a), fitting width (b), rubber thickness (c), fitting diameter (d), and hub fitting portion wall thickness (e) are different. Torsional dampers with various structures were subjected to a resonance point tracking method, and the maximum temperature (Tmax) reached at the surface of the rubber ring was measured.
It was also found that the maximum temperature reached at the surface of the rubber ring (Tmax) strongly depends on the wall thickness (e) of the hub fitting part, and that the temperature of the rubber ring does not rise in the region shown in FIG.
The area is expressed as follows.
Formula (1): Tmax≦-7.3e+141.1
Formula (2): 2.9≦e

The plot in Figure 6 shows the relationship between the wall thickness of the hub fitting part (e, unit: mm) and the maximum temperature reached at the surface of the rubber ring (Tmax, unit: °C), which was actually measured using the resonance point tracking method described above. This is data showing. The data are shown in Table 1.

As shown in FIG. 6, in the region expressed by formula (1) and formula (2), the maximum temperature (Tmax) reached at the surface of the rubber ring is lower than 120°C. Here, the rubber ring used in the present invention is made of a rubber composition containing EPDM as a main component, and has a loss coefficient (tan δ) of 0.18 or more when the surface temperature is 60±5°C. If the maximum surface temperature (Tmax) of such a rubber ring is 120° C. or lower, it will not be easily damaged.

Judging from the position of the plot shown in Figure 6, if formula (3): Tmax≧-30.0e+195.0 is satisfied, the maximum temperature (Tmax) reached at the surface of the rubber ring is sufficiently low to cause damage. It is thought that there is no fear. Therefore, it is preferable that the torsional damper of the present invention satisfies formula (3).

Furthermore, judging from the position of the plot shown in Figure 6, if formula (4): Tmax≧20e-30.0 is satisfied, the maximum temperature (Tmax) reached at the surface of the rubber ring is sufficiently low and there is a risk of damage. It is thought that there is no such thing. Therefore, it is preferable that the torsional damper of the present invention satisfies formula (4).

Further, the vibration ring wall thickness (a) is 2.9 mm or more according to equation (2), but preferably 3.0 mm or more.
Further, the vibration ring wall thickness (a) is preferably 8.0 mm or less, more preferably 7.0 mm or less, more preferably 6.0 mm or less, and preferably 5.5 mm or less. More preferred.

In the torsional damper of the present invention described in detail above, the rubber ring is extremely unlikely to be damaged due to heat generation.
Conventionally, there have been proposals for suppressing heat generation in a rubber ring by adjusting the material of the rubber ring (for example, the torsional damper described in Patent Document 1).
However, as in the present invention, heat generation in the rubber ring can be suppressed by adjusting the structure of the torsional damper, specifically, the radial thickness of the rim portion of the hub (thickness of the hub fitting portion). Such a technical idea did not exist.
It can be said that the present invention is not an invention that a person skilled in the art could easily conceive of, as it not only shows the technical idea, but also uses specific mathematical formulas to show the range in which heat generation in the rubber ring can be suppressed. .

1 Torsional damper 3, 30 Hub 31 Boss part 33 Stay part 35 Rim part 5, 50 Vibration ring 51 Pulley groove 7, 70 Rubber ring X Rotating shaft

Claims (4)

a hub fixed to a rotating shaft and having an outer peripheral surface on a circumference centered on the rotating shaft;
an annular vibration ring having an inner circumferential surface having a larger diameter than the outer circumferential surface of the hub on a circumference centered on the rotation axis;
It exists in a compressed state between the outer peripheral surface of the hub and the inner peripheral surface of the vibration ring, and is made of a rubber composition containing EPDM as a main component , and is tested by a high frequency vibration tester to have an excitation amplitude of ±0. The surface temperature measured by a non-contact surface thermometer was obtained by resonance point tracking method (natural frequency measurement) under the following conditions: 05deg, excitation phase: -90deg, ambient temperature: 23±3°C. A rubber ring having a loss coefficient (tan δ) of 0.18 or more at 60±5°C;
Equipped with
The surface temperature of the rubber ring is measured by a non-contact surface thermometer using a high-frequency vibration tester under the conditions of excitation amplitude: ±0.05deg, phase during excitation: -90deg, and ambient temperature: 23±3°C. When subjected to a resonance point tracking method (natural frequency measurement) performed until the temperature reaches 60 ± 5 °C , the maximum temperature reached on the surface of the rubber ring (Tmax) [°C] during continuous vibration at the resonance point, The wall thickness of the hub fitting part (e) [mm] is
Formula (1): Tmax≦-7.3e+141.1
Formula (2): 2.9≦e
A torsional damper that satisfies the following. When subjected to the resonance point tracking method, the maximum temperature reached at the surface of the rubber ring (Tmax) [°C] during continuous vibration at the resonance point and the wall thickness of the hub fitting part (e) [mm] are as follows:
moreover,
Formula (3): Tmax≧-30.0e+195.0
The torsional damper according to claim 1, which satisfies the following. When subjected to the resonance point tracking method, the maximum temperature reached at the surface of the rubber ring (Tmax) [°C] during continuous vibration at the resonance point and the wall thickness of the hub fitting part (e) [mm] are as follows:
moreover,
Formula (4): Tmax≧20e-30.0
The torsional damper according to claim 1 or 2, which satisfies the following. The above formula (2) is formula (2'): 2.9≦e≦8
The torsional damper according to any one of claims 1 to 3, which satisfies the following.

Images