JP6923315B2 - Tortional damper - Google Patents

Description

The present invention relates to a torsional damper that is mounted on a rotating shaft such as a crankshaft or a camshaft of an engine of a vehicle or the like to absorb the torsional vibration of the rotating shaft.

A torsional damper that transmits the rotation of a rotating shaft such as a crankshaft or camshaft of a vehicle engine to a driven device has a damper hub attached to the rotating shaft and an inertial ring arranged in the radial direction of the damper hub. A rubber member is interposed in the gap between the outer peripheral surface of the damper hub and the inner peripheral surface of the inertial ring.

The rubber member mounted between the damper hub and the inertial ring reduces the torsional vibration of the rotating shaft that occurs while the vehicle is running, prevents damage to the rotating shaft, and reduces the noise and vibration of engine vibration. It is an important member that plays a role.

Patent Document 1 discloses a rubber member for a damper obtained by cross-linking a rubber composition containing ethylene / propylene rubber and having a loss coefficient (tan δ) of more than 0.35 at −40 ° C. to 150 ° C.

Patent Document 2 vulcanizes a rubber member using ethylene propylene diene rubber (EPDM) as a main material and set so that the temperature dependence of the loss coefficient is within 15% per temperature change at 50 ° C. A bonded rubber damper device is disclosed.

Patent Document 3 discloses an EPDM composition for a torsional damper that is crosslinked with a hub of the torsional damper and an inertial ring and exhibits excellent heat resistance even in a high temperature atmosphere of about 120 ° C. to 140 ° C.

Japanese Unexamined Patent Publication No. 2007-090773 Japanese Unexamined Patent Publication No. 11-210832 Patent No. 4140415

In order to improve the durability of the torsional damper, it is an issue to suppress the temperature rise of the rubber member when the engine of the vehicle or the like is operating. However, the conventional rubber member applied to the torsional damper is a vehicle or the like. The temperature rise during engine operation was large, which was a factor that hindered the improvement of the durability of the torsional damper.

An object of the present invention is to provide a torsional damper having improved durability by suppressing a temperature rise of a rubber member.

A brief description of typical inventions disclosed in the present application is as follows.

The present invention is a torsional damper having a damper hub attached to a rotating shaft and rotating integrally with the rotating shaft, and an inertial ring attached to the damper hub via a rubber member. The rubber member is a torsional damper. The rubber member is made of a rubber composition in which the polymer is only EPDM, and the rubber member mounted between the damper hub and the inertial ring continuously attaches the torsional damper to the torsional damper at a resonance frequency of 400 Hz and a vibration amplitude of ± 0.05 °. The loss coefficient (tan δpi) at a surface temperature of 60 ± 5 ° C. when vibrated was 0.27 or more, and the torsional damper was continuously vibrated at a resonance frequency of 400 Hz and a vibration amplitude of ± 0.05 °. The maximum surface temperature (Tmax) of the rubber member at that time represents a coefficient in the range of −46.9 to -60.4 in the following equation Tmax = α × ln (tanδpi) + β ≦ 100 (in the equation, α represents a coefficient in the range of −46.9 to -60.4). , Β represents a coefficient in the range of +9.4 to +27.7).

Among the inventions disclosed in the present application, the effects obtained by representative ones will be briefly described as follows.

According to the present invention, it is possible to suppress a temperature rise of the rubber member mounted between the damper hub and the inertial ring, so that it is possible to provide a torsional damper with improved durability.

It is a perspective view which shows the torsional damper which is one Embodiment of this invention. It is a partially cutaway perspective view of the torsional damper shown in FIG. It is a figure explaining the method of measuring the twist angle of the rubber member attached to a torsional damper. It is a figure which shows the relationship between the amount of carbon black contained in the rubber composition constituting the rubber member of the torsional damper shown in FIG. 1 and a loss coefficient (tan δi). It is a partially cutaway perspective view which shows the assembly method of the torsional damper shown in FIG. It is an enlarged view (average compression ratio explanatory view) of the main part of a torsional damper shown in FIG. It is a figure which shows the measuring method of the surface temperature of the rubber member attached to a torsional damper.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a torsional damper according to an embodiment of the present invention, and FIG. 2 is a partially cutaway perspective view of the torsional damper shown in FIG.

The torsional damper 10 of the present embodiment is attached to the tip of the crankshaft of an engine of a vehicle or the like, and is used to transmit the rotation of the crankshaft to a driven device such as an alternator or a power steering. A damper hub 11, an inertial ring 12, and an annular rubber member 13 are provided.

The damper hub 11 has a disc portion 11a extending in the radial direction and a boss portion 11b integrally provided in the radial central portion thereof, and the boss portion 11b is fastened to the tip of the crankshaft and is centered on the central axis C. It is driven to rotate. The damper hub 11 is made of cast iron such as FC250 and FCD450.

The inertial ring 12 is arranged on the outer side of the damper hub 11 in the radial direction, and a pulley groove 12a on which a belt is hung is provided on the outer peripheral surface thereof to form a pulley for power transmission. The inertial ring 12 is made of cast iron such as FC250.

The rubber member 13 mounted between the damper hub 11 and the inertial ring 12 is inserted into the gap between the outer peripheral surface coaxial with the central axis C of the damper hub 11 and the inner peripheral surface of the inertial ring 12 facing the outer peripheral surface. It reduces the torsional vibration of the crankshaft that occurs while the vehicle is running, prevents damage, and reduces the noise and vibration of the engine vibration.

The present inventors discuss the relationship between the calorific value of the rubber member 13 after mounting the torsional damper and the loss coefficient (tanδpi) at 60 ° C. in order to suppress the temperature rise of the rubber member 13 when the engine of a vehicle or the like is operating. As a result of diligent studies, it was found that the rubber member having a large loss coefficient (tan δpi) has a small calorific value of the rubber member itself. The reason and experimental results will be described below.

In the following, the loss coefficient of the rubber member 13 after mounting the torsional damper at 60 ° C. is tanδpi, the loss coefficient of the rubber member 13 after mounting the torsional damper at 120 ° C. is tanδph, and the rubber member 13 before mounting the torsional damper. The loss coefficient at 60 ° C. is described as tanδi, and the loss coefficient of the rubber member 13 before mounting the torsional damper at 120 ° C. is described as tanδh.

<Relationship between loss factor (tan δpi) and twist angle (θts) of rubber member>
First, the torsional damper 100 is attached to the jig 101 corresponding to the crankshaft of the engine as shown in FIG. 3, and the two acceleration sensors 102 and 103 attached to the jig 101 and the torsional damper 100 are used. The twist angle of the rubber member mounted on the torsional damper 100 was measured. As the rubber member of the torsional damper 100, the rubber member of the present invention and the rubber member of the comparative example are used, and the twist angle (θts) of a total of four types of rubber members containing EPDM as the main component is measured by the resonance point tracking method. bottom. The results are shown in Table 1.

<Measurement conditions>
・ Vibration amplitude: ± 0.35 × 10 ^-3 rad (± 0.02 °)
・ Sweep speed: 100Hz / min

Further, the loss coefficient (tan δpi) of the above-mentioned four types of rubber members is measured by the measurement method described in the examples described later, and the twist angle (θts) of the rubber member and the loss coefficient (tan δpi) at the rubber member surface temperature of 60 ° C. Table 2 plots the relationship with.

Generally, when vibration energy is applied to a viscoelastic body with large internal damping such as a rubber member, a part of this energy is stored as elastic energy, and the remaining energy becomes heat due to vibration damping, and the temperature of the viscoelastic body. To raise.

Here, it is known that the work per unit volume performed by the external force for one cycle of vibration is equal to the amount of heat (Q) per unit volume obtained by the system. At this time, the amount of heat (Q) is represented by the following formula (1).

(In the equation, τ (t) is the shearing force as an external force, A is the shear section area, h is the shear thickness, and u is the displacement of the viscoelastic body.)
When du (t) in the above equation (1) is expressed using the shear strain dγ (t), the following equation (2) is derived.

(In the formula, G "(ω, T) is the loss shear modulus, γ is the shear strain, ω is the angular frequency, and T is the temperature.)
Further, in general, the loss coefficient (tan δ) is expressed by the following equation (3).

(In the formula, G'(ω, T) represents the shear modulus)
Therefore, from the above equations (2) and (3), the amount of heat (Q) is finally expressed by the following equation (4).

(In the equation, f represents frequency and γ represents shear strain.)

As shown in Table 2, it can be seen that the twist angle (θts) of the rubber member after mounting the torsional damper decreases as the loss coefficient (tan δpi) of the rubber member at a surface temperature of 60 ° C. increases. In particular, as can be seen from Table 2, a clear negative correlation is observed between the twist angle of the rubber member and the loss coefficient (tan δpi) at the surface temperature of the rubber member at 60 ° C., which is shown by the following equation. I understood.

Twisting angle of rubber member (θts) = α × ln (tanδpi) + β
However, the coefficient in the range of α = -0.239 to -0.245 β = the coefficient in the range of -0.0653 to -0.0753 The coefficient of α and β is the measurement error of the rubber twist angle (± 0.005). °) And the coefficient resulting from the measurement error (± 0.005) of the loss coefficient (tan δpi).

As described above, the twist angle (θts) of the rubber member and the loss factor (tan δpi) at the surface temperature of the rubber member at 60 ° C. have a negative correlation. That is, it means that the larger the loss coefficient (tan δpi) at the surface temperature of the rubber member is 60 ° C., the smaller the shear strain γ and the smaller the energy given to the torsional damper, and as a result, the above equation (4) Therefore, it can be estimated that the larger the loss coefficient (tan δpi), the smaller the amount of heat (Q), and as a result, the smaller the temperature rise.

Therefore, the present inventors discuss the relationship between the loss coefficient (tan δpi) at the surface temperature of the rubber member at 60 ° C. after mounting the torsional damper and the maximum surface temperature reached when the surface maximum temperature of the rubber member becomes a steady state. , The following examination was conducted.

<Relationship between the loss factor (tan δpi) and the maximum surface temperature (Tmax) at a surface temperature of 60 ° C. of the rubber member>
Using the resonance point tracking method described in Examples described later, the maximum surface temperature of two typical rubber members (the product of the present invention and the product of Comparative Example shown in Table 1) having different loss factors (tan δpi) is not set. It was measured using a contact surface thermometer. The results are shown in Table 3.

As can be seen from Table 3, the surface temperature of the rubber member becomes a steady state at least 30 minutes after the start of the test.

Further, Table 4 shows a plot of the relationship between the loss coefficient (tan δpi) at a surface temperature of 60 ° C. and the loss coefficient (tan δph) at 120 ° C. and the maximum temperature reached on the surface of the rubber member.

In the surface temperature measurement, as shown in FIG. 7, the torsional damper 100 is set directly on the high-frequency torsional vibration tester, and the resonance point, which is the resonance frequency, is continuously tracked (resonance point tracking method) as described below. Measured with a non-contact surface thermometer under the conditions.

<Measurement conditions>
・ Vibration amplitude: ± 0.05 °
-Resonance frequency: 400Hz (+ 0Hz to -30Hz)
Here, the resonance frequency is measured under the following measurement conditions by using the resonance sweep method (natural frequency measurement) by a high-frequency torsional vibration tester. The resonance frequency error (+ 0 Hz to −30 Hz) is an error in which the resonance frequency fluctuates with the passage of the test time.

<Measurement conditions>
・ Vibration amplitude: ± 0.85 × 10 ^-3 rad (± 0.05 °)
・ Sweep speed: 100Hz / min
By the way, in general, the resonance frequency (fn) of a torsional damper is
fn = (1 / 2π) × (k / Id) ^1/2
(Here, k: spring constant, Id: inertial mass).

Therefore, the resonance frequency can take various values depending on the inertial mass of the rubber member and the damper, which are spring constants, but the resonance frequency of the torsional damper used in this measurement was 400 Hz.

As a result, as shown in Table 4, a good negative correlation was observed between the loss coefficient (tan δpi) at the surface temperature of the rubber member at 60 ° C. and the maximum surface temperature of the rubber member. It was found that as the loss coefficient (tan δpi) at a surface temperature of 60 ° C. increased, the maximum temperature reached on the surface of the rubber member decreased. This means that as the loss coefficient (tan δpi) at the surface temperature of the rubber member at 60 ° C. increases, the shear strain γ (≈ twist angle) decreases, so that the energy given to the torsional damper decreases, and as a result, the energy given to the torsional damper decreases. From the above equation (4), it was possible to test the hypothesis that the amount of heat (Q) is small, and as a result, the temperature rise is small.

Further, the negative correlation between the loss coefficient (tan δpi) at the surface temperature of the rubber member at 60 ° C. and the maximum surface temperature of the rubber member is particularly good at the surface temperature of 60 ° C., and the loss coefficient (tan δpi) at the surface temperature of 60 ° C. ) And the maximum surface temperature (Tmax) of the rubber member, it was found that there is a relationship as shown in equation (5).

(In the equation, 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).

The coefficients α and β in the equation (5) are coefficients obtained from the measurement error of the loss coefficient (tan δpi) of ± 0.005 and the surface temperature measurement error of ± 5 ° C. Further, the maximum surface temperature (Tmax) means a temperature rise of the rubber member + an environmental temperature (23 ° C. in the case of Table 4).

On the other hand, a good correlation cannot be obtained between the loss coefficient (tan δph) at the surface temperature of the rubber member at 120 ° C. and the maximum surface temperature (Tmax). This is because the rubber cross-linking density of EPDM changes due to the characteristics of the EPDM rubber composition, for example, the additive added to improve the loss coefficient at high temperature, so that the loss coefficient on the high temperature side (120 ° C. in this case) is changed. It is considered that a good correlation between (tan δph) and the maximum surface temperature of the rubber member was not obtained.

When the surface temperature of the rubber member is higher than 100 ° C., the material physical properties (for example, tensile strength, modulus, etc.) of the rubber composition constituting the rubber member are lowered, and the durability is deteriorated. Therefore, the upper limit temperature was set to 100 ° C.

Next, the configuration of the rubber member 13 of the present embodiment will be described in detail.

The rubber member 13 of the present embodiment is obtained by vulcanizing a rubber composition containing ethylene, propylene, and diene ternary copolymer (EPDM) as a main component into a predetermined shape (cylindrical shape in this example) by a conventional method. It was made.

Further, there is a correlation between the amount of carbon black added to the rubber composition and the loss coefficient (tan δi) of the rubber member alone before mounting the torsional damper, and as shown in FIG. 4, the amount of carbon black The loss coefficient (tan δi) increases in proportion to the increase. Therefore, it is preferable to add 100 parts by weight or more of carbon black to 100 parts by weight of EPDM to the rubber composition.

Further, 50 parts by weight or more of the process oil is added to the rubber composition, and the polymer fraction of the EPDM is preferably 20% or more and 40% or less (see Table 6 of Examples described later).

From the viewpoint of durability, it is more preferable to add 140 parts by weight or more of carbon black and 70 parts by weight or more of process oil to 100 parts by weight of EPDM (see Table 6 of Examples described later). ).

Furthermore, there is also a correlation between the particle size of carbon black added to the rubber composition and the loss coefficient (tan δi) of the rubber member at 60 ° C. The smaller the particle size of carbon black, the more the loss coefficient (tan δi). Becomes larger.

In other words, the larger the iodine adsorption amount of carbon black, the smaller the particle size of carbon black and the larger the loss factor (tan δi) of the rubber member at 60 ° C. In addition, the larger the amount of DBP (plasticizer: Dibutyl phthalate) oil absorbed, the larger the structure of carbon black and the better the conductivity. Therefore, when the rubber member is attached to the torsional damper, it is torsional. It is possible to prevent the damper from being charged and at the same time to improve the durability.

Specifically, the carbon black added to the rubber composition preferably has an iodine adsorption amount of 70 mg / g or more and 150 mg / g or less, and a DBP oil absorption amount of 40 ml / 100 g or more and 120 ml / 100 g or less (see Table 5). ).

By the way, in addition to carbon black, the rubber composition contains a peroxide, a co-crosslinking agent and the like as a vulcanizing agent.

As a peroxide,
1,1-bis (tert-butylperoxy) cyclohexane,
2,5-Dimethyl-2,5-di (tert-butylperoxy) hexane,
2,5-Dimethyl-2,5-di (tert-butylperoxy) hexyne-3,
2,5-dimethyl-2,5-di (benzoylperoxy) hexane,
1,3-Di (2-tert-butylperoxyisopropyl) benzene,
Di-tert-butyl peroxide,
Dicumyl peroxide,
N-Butyl-4,4-di (tert-butylperoxy) valerate,
tert-butylcumyl peroxide,
Etc. can be used.

As a co-crosslinking agent
Triallyl isocyanate,
Ethylene glycol dimethacrylate,
Trimethylolpropane trimethacrylate,
Triallyl cyanurate,
Quinone dioxime,
1,2-polybutadiene,
Etc. can be used.

In addition to the above-mentioned components, the rubber composition contains well-known rubber additives (process oil (mineral oil), plasticizer, zinc oxide, zinc stearate, anti-aging agent, etc.).

In the torsional damper 10 of the present embodiment, after the rubber composition as described above is vulcanized to form an annular rubber member 13, the boss portion 11b of the damper hub 11 is in the vertical direction as shown in FIG. With the damper hub 11 and the inertia ring 12 arranged on a support base (not shown) so as to be It is manufactured by press-fitting the rubber member 13 into the gap portion 14. The parts manufactured in this way are called press-fit type torsional dampers.

When the rubber member 13 is press-fitted into the gap 14 between the damper hub 11 and the inertial ring 12, it is preferable that the rubber member 13 is press-fitted so that the average compressibility of the rubber member 13 is in the range of 10% to 40%. When the average compressibility of the rubber member 13 is less than 10%, the slip torque of the torsional damper 10 does not reach a desired value, and it becomes difficult for power to be transmitted to the belt. Further, if the average compressibility is larger than 40%, stress concentration on the rubber member 13 causes cracks in the rubber, which deteriorates the durability, which is not preferable.

Further, the average compressibility of the rubber member 13 is more preferably in the range of 10% to 30%. When the average compressibility is within this range, it is possible to suppress the generation of rubber wear powder due to friction with the inertial ring 12 or the damper hub 11, especially in the durability test, and good durability can be obtained. Further, the press-fitting property is improved, and stable dimensional accuracy can be realized.

Here, the compressibility of the rubber member 13 is the compressibility in the radial direction of the torsional damper, and the compressibility in the radial direction means that the thickness (t ₀ ) of the rubber member 13 in FIG. 5 before mounting is compressed by mounting. The thickness is (t ₁ ), and the radial compressibility is expressed by the equation (6).

By the way, when the rubber member 13 is inserted into the damper hub 11 and the inertia ring 12, the gaps between the damper hub 11 and the inertia ring 12 are not at regular intervals as shown in FIG. , It has a wide gap so that the rubber member 13 can be easily inserted.

In addition, depending on the type of torsional damper, convex protrusions are provided in the left-right direction (on the paper surface) of the rubber member press-fitted near the center of the inner circumference of the inertial ring and the center of the hub to prevent the rubber member from coming off. ing.

As described above, when the rubber member is press-fitted into the torsional damper, the gap formed between the inner peripheral surface of the inertial ring and the outer peripheral surface of the hub is not constant. That is, as shown in FIG. 6, it has a gap distance as shown in t1 to t5. Therefore, the compressibility of the rubber member is partially different.

Therefore, the weighted average compression rate of the regions having different compression rates as shown in the equation (7) was used as the average compression rate.

However, t ₀ : thickness of the rubber member before press fitting
t _n : Maximum gap spacing when inserted (press-fitted) into different gaps
Thickness of rubber member
L ₀ : Width of torsional damper
L _n : Length of each gap in the torsional damper in the width direction
n: The number of regions having different compression rates, and is an integer from 1 to 5.

Note that t1 and t5 are gap distances at the center positions (L1 / 2, L5 / 2) of the inclined opening portions (L1, L5).

Further, if L5 does not have an inclined portion and is not opened, if t5 = t4, then n = 4. Further, there is a case where there is no convex portion in the central portion, and in that case, if t2 to t4 have the same void distance, n = 3.

In this way, regions with the same gap spacing are counted as n = 1, and if there are regions with different gap spacing, n gradually increases, and n can be up to 5 depending on the arbitrary gap spacing.

Further, from the viewpoint of improving the durability of the torsional damper 10, the rubber member 13 before mounting the torsional damper has a ratio (300) of the modulus (Mpa) at the time of 300% extension and the modulus (Mpa) at the time of 50% extension. It is desirable that the% elongation modulus / 50% elongation modulus) be 7.2 or more. When the ratio of the modulus at 300% elongation (Mpa) to the modulus at 50% elongation (Mpa) (modulus at 300% elongation / modulus at 50% elongation) is less than 7.2, an external force was applied. At that time, the distortion of the rubber member becomes large, and the rubber member may be damaged during durability.

As a method for manufacturing the torsional damper 10 of the present embodiment, in addition to the above-mentioned press-fitting method, vulcanization adhesion in which a damper rubber composition constituting a rubber member is injected into a gap between a damper hub 11 and an inertial ring 12 and heated. There is a law. Parts manufactured by the vulcanization bonding method are called vulcanization bonding type torsional dampers.

According to the vulcanization bonding method, the original characteristics of the rubber member are more likely to be exhibited as compared with the press-fitting method, but poor bonding is likely to occur, and adjustment is required to increase the bonding force with the damper hub 11 and the inertial ring 12. .. Since the rubber member is compressed by the press-fitting method, the original characteristics of the damper rubber composition are sacrificed to some extent, but there is an advantage that poor adhesion does not occur in the simple process of press-fitting.

(Example)
Next, examples of the present invention will be described.

<Manufacturing of rubber parts>
(Adjusting process of damper rubber composition)
First, 100 parts by weight of EPDM was put into a 3.5 liter Banbury mixer, and after kneading at a rotation speed of 40 rpm for 1 minute, 100 parts by weight of carbon black, 50 parts by weight of process oil, 5 parts by weight of zinc oxide, and 1 part of zinc stearate were added. A part by weight and 2 parts by weight of an antiaging agent were added and kneaded for 2 minutes, and after further kneading for 1 minute, the kneaded product was discharged from the Banbury mixer. Subsequently, the discharged kneaded product was wound around a 12-inch roll having a roll interval of 5 mm to form a sheet, and the molded dough was left at room temperature for 12 hours or more.

Next, the above dough was wound around a 6-inch roll with a roll spacing of 4 mm to form a peroxide, 2.5 parts by weight of 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, and a co-crosslinking agent. As a result, 2 parts by weight of trimethylolpropane trimethacrylate was kneaded, cut back 3 times each on the left and right, and then rounded 5 times, and then formed into a sheet.

(Vulcanization process of damper rubber composition)
Next, the above sheet is set in a mold and press vulcanized at 180 ° C. for 10 minutes to prepare a rubber sheet having a thickness of 2 mm, and further heat-treated in a constant temperature bath at 150 ° C. for 6 hours. rice field.

Further, the rubber members of Examples 2 to 5 and Comparative Examples 1 and 2 shown in Table 6 were produced in the same manner as described above except that the composition ratio of the damper rubber composition was changed. However, in Examples 1 to 5, carbon black 1 in which the iodine adsorption amount and the DBP oil absorption amount were in the range shown by the broken line in Table 5 was used, and in Comparative Example 2, carbon black 2 was used.

<Evaluation of rubber members>
1. 1. Based on JIS K6394, the loss coefficient (tanδi) at 60 ° C., the loss coefficient (tanδh) and the loss coefficient ratio (tanδh / tanδi) of the rubber members of Examples 1 to 5 and Comparative Example 2 were determined according to the following conditions. Each was measured. The results are shown in Table 6.

Measuring instrument: Viscoelastic analyzer YR-7130 manufactured by Ueshima Seisakusho
Deformation method: Tensile frequency: 100Hz
Amplitude: ± 1%
Preload: 480mN
Specimen shape: Collected from the rubber member after vulcanization molding
20 mm (grasping interval) x 4 mm (width) x 2 mm (thickness) strip-shaped piece

2. Using a durometer A based on JIS K6253, the hardness of the rubber members of Examples 1 to 5 and Comparative Example 2 was measured by a method of reading within 1 second. The results are shown in Table 6.

3. 3. Tensile strength (Mpa), elongation (%) and modulus (modulus at 300% elongation, modulus at 50% elongation and theirs) of the rubber members of Examples 1 to 5 and Comparative Example 2 based on JIS K6251. Ratio) was measured. The results are shown in Table 6.

<Evaluation of press-fit type torsional damper>
1. 1. An annular rubber member (see rubber member 13 in FIG. 5) was produced using the rubber compositions of Examples 1 to 5 and Comparative Examples 1 and 2, and the average compressibility was 10 in the gap between the hub and the inertial ring. A torsional damper was manufactured by press-fitting at ~ 40%.

Next, the loss coefficient (tan δpi) of the rubber member mounted on the torsional damper (Examples 1 to 5, Comparative Examples 1 and 2) at a surface temperature of 60 ° C. and the loss coefficient of the rubber member at a surface temperature of 120 ° C. ( The tanδph) and the loss coefficient ratio (tanδph / tanδpi) were measured by the resonance sweep method (natural frequency measurement) using a high-frequency vibration tester.

<Measurement conditions>
-Rubber temperature: 60 ± 5 ° C, 120 ± 5 ° C
・ Vibration amplitude: ± 1.7 × 10 ^-3 rad (± 0.1 °)
・ Sweep speed: 100Hz / min

1. 1. Further, the maximum surface temperature of each rubber member at the time of continuous vibration at the resonance point of the torsional damper (Examples 1 to 5, Comparative Examples 1 and 2) (the resonance point tracking method described above) is not contacted. It was measured with a surface thermometer, and at the same time, the durability after a lapse of a predetermined time was evaluated by the same method. The results are shown in Table 6. Regarding the durability in Table 6, the rubber that was damaged before the lapse of the predetermined time is marked with "x", and after the lapse of the predetermined time, there is no abnormality in the appearance of the rubber part, but it is over the predetermined time. "○ (circle)" indicates that the physical property value of the rubber member has changed (for example, modulus), and "◎ (double circle)" indicates that the appearance of the rubber part has not changed after a predetermined period of time. ".

As shown in Table 6, it was found that the torsional dampers of Examples 1 to 5 exhibited good durability by suppressing the temperature rise of the rubber member.

Although the torsional damper of the present invention has been described in detail above, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the gist thereof. For example, the torsional damper of the present invention can be applied to reduce torsional vibration not only in crankshafts of automobiles, construction machines, ships, etc., but also in various rotating shafts such as engine camshafts, and has an outer peripheral surface. It can also be applied to a torsional damper having a type of inertial ring in which a pulley groove is not formed, a torsional damper having a hub having no boss portion, and the like.

10 Tortional damper 11 Damper hub 11a Disc part 11b Boss part 12 Inertia ring 12a Pulley groove 13 Rubber member 14 Gap part 100 Tortional damper 101 Jig 102, 103 Accelerometer

Claims (4)

A damper hub that is attached to the rotating shaft and rotates integrally with the rotating shaft,
An inertial ring attached to the damper hub via a rubber member,
It is a torsional damper with
The rubber member is made of a rubber composition in which the polymer is only EPDM.
The rubber member mounted between the damper hub and the inertial ring has a surface temperature of 60 ± 5 ° C. when the torsional damper is continuously vibrated at a resonance frequency of 400 Hz and a vibration amplitude of ± 0.05 °. Loss coefficient (tan δpi) is 0.27 or more,
The maximum surface temperature (Tmax) of the rubber member when the torsional damper is continuously vibrated at a resonance frequency of 400 Hz and a vibration amplitude of ± 0.05 ° is calculated by the following equation.
Tmax = α × ln (tanδpi) + β ≦ 100
(In the equation, 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).
A torsional damper that meets the requirements. A damper hub that is attached to the rotating shaft and rotates integrally with the rotating shaft,
An inertial ring attached to the damper hub via a rubber member,
It is a torsional damper with
The rubber member is made of a rubber composition in which the polymer is only EPDM.
The rubber member before being attached to the damper hub has a ratio of the modulus at 300% elongation to the modulus at 50% elongation of 7.2 or more.
The rubber member mounted between the damper hub and the inertial ring has a surface temperature of 60 ± 5 ° C. when the torsional damper is continuously vibrated at a resonance frequency of 400 Hz and a vibration amplitude of ± 0.05 °. The loss factor of time (tan δpi) is 0.27 or more,
The maximum surface temperature (Tmax) of the rubber member when the torsional damper is continuously vibrated at a resonance frequency of 400 Hz and a vibration amplitude of ± 0.05 ° is calculated by the following equation.
Tmax = α × ln (tanδpi) + β ≦ 100
(In the equation, α represents a coefficient in the range of -46.9 to -60.4, and β is +9.4 to +27.7.
Represents the coefficient of the range)
A torsional damper that meets the requirements. In the torsional damper according to claim 1 or 2.
The rubber member before mounting the torsional damper is a vulcanized molded rubber composition.
Wherein the rubber composition to the EPDM100 parts, the loss factor (tanδi) affecting carbon black only 100 parts by weight or more, more process oil 50 parts by weight are added respectively,
A torsional damper in which the polymer fraction of EPDM, which is the ratio of parts by weight of EPDM to the total weight of the rubber composition, is 20% or more and 40% or less. In the torsional damper according to any one of claims 1 to 3,
The rubber member has a gap formed by the damper hub and the inertial ring.
The gap portion has a plurality of gap intervals and has a convex gap portion in at least a part of the gap portion, and the rubber member is press-fitted into the gap portion in the radial direction of the rubber member after press-fitting. The average compression ratio of is a torsional damper expressed by the following formula.

However, t0: thickness of the rubber member before press fitting
tun: Thickness of rubber member when inserted (press-fitted) into different voids
L0: Width of torsional damper
Ln: Length of each gap in the torsional damper in the width direction
n: The number of regions having different compression rates, and is an integer from 1 to 5.

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