JP2018197572A - Torsional damper - Google Patents

Abstract

To provide a torsional damper capable of suppressing generation of abrasion powder and improving durability even when a rubber member having high damping characteristics is used.SOLUTION: A torsional damper 1 is characterized in that a loss coefficient (tanδpi) of a rubber member at a surface temperature 60±5°C of the rubber member upon torsional damper resonance is larger than 0.23, shear strain of the rubber member in such a state as to be press-fitted into the torsional damper is larger than 35% and is less than 60%, surface roughness of a gap part 5 between a hub outer peripheral face 25A and an inertia ring inner peripheral face 3A is 4 to 30 μm, and an abrasion reduction area 53 having surface roughness smaller than those of the hub outer peripheral face 25A and the inertia ring inner peripheral face 3A which form a main compression gap part 51 is provided on the hub outer peripheral face 25A and the inertia ring inner peripheral face 3A which form an inclination gap part 52 at a press-fitting inlet side of the rubber member 4.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a torsional damper that is attached to a rotating shaft such as a crankshaft or a camshaft of an engine and absorbs torsional vibration of the rotating shaft.

  Conventionally, a torsional damper is attached to one end of a rotary shaft such as a crankshaft or a camshaft of an engine mounted on a vehicle in order to absorb torsional vibrations generated by rotational fluctuation of the rotary shaft. Generally, a torsional damper mounted on an engine crankshaft is used as a damper pulley, and transmits a part of engine power to an engine accessory via a power transmission belt.

  This torsional damper has a hub to which the tip of the crankshaft is attached to a boss portion, and an inertia ring disposed radially outward with respect to the hub, and includes a hub outer peripheral surface and an inertia ring inner peripheral surface. A rubber member is inserted in the gap. This rubber member serves to reduce the torsional vibration of the rotating shaft that occurs during traveling of the vehicle to prevent the rotating shaft from being damaged, and to reduce the vibration transmitted from the engine and the noise generated by the vibration. At this time, the rubber member inserted between the inertia ring and the hub undergoes a torsional movement that is shifted in the circumferential direction between the inertia ring and the hub. At this time, if the load due to the torsional vibration applied to the rubber member exceeds a certain level, the rubber member cracks. In particular, it is known that durability is lowered when a high damping rubber member is used.

  For example, in Patent Document 1, a cylindrical surface portion and a tapered stress relieving portion are provided on the outer peripheral surface of the hub, and a cylindrical surface portion facing the cylindrical surface portion on the inner peripheral surface of the mass body arranged on the outer peripheral side of the hub. It is disclosed that a taper-like stress relaxation part is provided opposite to the stress relaxation part, and an elastic body made of a rubber-like elastic material is press-fitted between the hub and the mass body from one axial direction. In Patent Document 1, a smooth surface that does not have unevenness is provided in a portion of the elastic body that is in contact with the stress relaxation portion, and the elastic body is prevented from swelling when the elastic body is press-fitted. A technique is disclosed in which unevenness for retaining an adhesive or lubricating oil is provided in a portion in contact with the surface portion to achieve a strong connection.

  Patent Document 2 discloses a fitting type damper in which a polymer elastic body such as rubber is press-fitted from one axial direction between a hub made of metal parts and the mass body, and includes a hub and / or a mass body. The surface roughness of the metal surface to which the polymer elastic body is fixed is 5 to 50 μm Rz, and is used as an anti-slip agent between the hub and the polymer elastic body and / or between the mass body and the polymer elastic body. A technique for realizing a damper having a high fixing force by fixing an organosilane is disclosed.

  Furthermore, Patent Document 3 discloses that an outer peripheral surface of a hub into which an annular elastic body is press-fitted and an annular mass body are provided for the purpose of providing a torsional damper having durability without vibration-proof characteristics changing over a long period of time. A gap formed between the circumferential surface and the circumferential surface has a main gap that holds the annular elastic body in the axial center in a compressed state, and at least one end of both axial ends is larger than the main gap. It is disclosed that a sub-gap part that has a gap and forms a compressive force holding part that holds the end part in a compressed state is provided at the end part of the annular elastic body.

  Further, in Patent Document 4, a torsional damper that obtains a dynamic vibration absorption effect by resonance of a spring-mass system has a hub and a mass for the purpose of improving the damping performance without depending on the mass increase of the mass body. It is disclosed that a sliding bearing is slidably contacted between at least one of the hub and the mass body between the bodies.

JP-A-11-44344 JP 2011-263423 A JP 2010-151217 A JP-A-2015-38366

  By the way, in order to improve the dynamic vibration absorption effect of this type of torsional damper, it is effective to increase the mass of the inertia ring. Therefore, the use of rubber members having high damping characteristics has been studied.

  However, in consideration of press-fit workability, when a taper part that gradually reduces the amount of compression is formed at the end of the press-fit side in the axial direction, rubber with a low amount of compression sandwiched between the end of the press-fit side When a constant constant load is applied to the edge of the member, the rubber member having high damping characteristics becomes prominent due to friction caused by rubbing against the surface of the hub or inertia ring. The durability of the deteriorated. In addition, torsional vibration can be reduced by using a rubber member having a high damping characteristic, but the wear resistance of the rubber member is reduced by an additive added to increase the damping. If the surface is rubbed against a large uneven surface, the generation of wear powder increases.

  For this reason, there has been a demand from the market for the development of a torsional damper that can suppress the generation of abrasion powder and improve the durability of the rubber member even when a rubber member having high damping performance is used. .

  Therefore, the inventors of the present invention have provided the following torsional dampers as a result of intensive studies. That is, the torsional damper according to the present invention includes a hub that is fixed to a rotating shaft and has an outer peripheral surface that is substantially concentric with the rotating shaft, and an inner periphery that is opposed to the outer peripheral surface of the hub and is substantially concentric with the outer peripheral surface. An inertia ring having a surface, a hub outer peripheral surface, and a rubber member press-fitted into a gap between the inertia ring inner peripheral surface, the rubber member at the time of torsional damper resonance Rubber member in which the loss factor (tan δpi) of the rubber member at a surface temperature of 60 ± 5 ° C. is greater than 0.23 and is press-fitted into the torsional damper as measured by the total load torque of the auxiliary machine at a high temperature A main compression gap portion that compresses and holds the rubber member formed by the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring, and the hub. The main compression includes an outer peripheral surface end portion and an inertia ring inner peripheral surface end portion, and an inclined gap portion that inclines in a direction in which the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring are separated from each other toward the end surface. The surface roughness of the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring forming the gap portion and the inclined gap portion is 4 μm or more and 30 μm or less, and the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring forming the inclined gap portion And a friction reduction region having a smaller surface roughness than the outer peripheral surface of the hub forming the main compression gap and the inner peripheral surface of the inertia ring.

  In the torsional damper according to the present invention, the surface roughness of the hub outer peripheral surface and the inertia ring inner peripheral surface of the friction reduction region is 4 μm or more and 15 μm or less, and the hub outer surface other than the friction reduction region and the inertia ring The surface roughness of the inner peripheral surface is preferably greater than 15 μm and 30 μm or less.

  In the torsional damper according to the present invention, the radial average compression ratio of the rubber member represented by the following formula (1) is defined by the average compression ratio of the main compression gap and the average compression ratio of the inclined gap. The main compression gap is preferably 30% or more and 40% or less, and the inclined gap is preferably 10% or more and 20% or less.

ただし、ｔ_０：圧入前のゴム部材の厚み
ｔ_ｎ：空隙部に圧入したときの各領域におけるゴム部材の厚み
Ｌ_０：トーショナルダンパの幅方向の長さ
Ｌ_ｎ：空隙部の各領域の幅方向の長さ
ｎ：圧縮率が異なる領域の数であり、２〜７までの整数。

However, t _0: thickness t n of the rubber member before _press-: thickness of the rubber member in each region when pressed into the gap portion L _0: the width direction of the torsional damper length L _n: each region of the air gap Length in the width direction n: the number of regions having different compression ratios, and an integer from 2 to 7.

  In the torsional damper according to the present invention, it is preferable that an inclination angle of the inclined gap portion is 25 ° or more and less than 40 °.

  The rubber member used for the torsional damper according to the present invention preferably has an elongation percentage of more than 34% and less than 62% when a tensile stress of 1.4 MPa is applied to the rubber member before press fitting a plurality of times.

  The torsional damper according to the present invention has a loss coefficient (tan δph) of the rubber member at a surface temperature of 120 ± 5 ° C. at the time of resonance of the torsional damper of 0.21 or more. Loss coefficient (tan δph) of the rubber member at a surface temperature of 120 ± 5 ° C. and loss coefficient (tan δpi) of the rubber member at a surface temperature of the rubber member at torsional damper resonance of 60 ± 5 ° C. Loss factor ratio (tan δph / tan δpi) is preferably 0.66 or more.

  In the torsional damper according to the present invention, the loss factor (tan δi) at 60 ° C. of the rubber member before press-fitting is 0.39 or more, and the loss coefficient (tan δh) at 120 ° C. and the loss coefficient (tan δi) at 60 ° C. The loss factor ratio (tan δh / tan δi) is preferably 0.87 or more.

  The rubber member used for the torsional damper according to the present invention preferably has a modulus at 50% elongation of the rubber member before press-fitting is greater than 1.28 MPa and less than 1.82 MPa.

  In the torsional damper according to the present invention, the rubber member before press-fitting is obtained by vulcanization molding of a rubber composition, and the rubber composition is 100 parts by weight or more of EPDM with respect to 100 parts by weight of EPDM, Preferably, 40 parts by weight or more of process oil is added, and the polymer fraction of the EPDM is 20% by weight or more and 40% by weight or less.

  In the rubber composition of the present invention, the iodine adsorption amount of the carbon black is preferably 70 mg / g or more and 185 mg / g or less.

Further, the rubber composition of the present invention preferably has DBP oil absorption of the carbon black is less than 40 cm ^3/100 g or more 120 cm ^3/100 g.

  According to the present invention, even when a rubber member having high damping characteristics that easily wears is used, the surface roughness of the inclined gap portion of the gap portion formed in the gap portion between the hub and the inertia ring is such that the rubber member is Since it is smaller than the main compression gap portion to be compressed and held, it is possible to remarkably suppress the generation of wear powder caused by the rubber member rubbing against the inclined gap portion. As a result, it is possible to improve the durability of the torsional damper, and at the same time, torsional vibration can be reduced by using a rubber member having a high damping characteristic, so that the weight of the torsional damper can be reduced.

It is a perspective view of the torsional damper as an embodiment to which the present invention is applied. FIG. 2 is a partially broken perspective view of the torsional damper of FIG. 1. It is a partially broken perspective view of a torsional damper before press-fitting a rubber member. It is a partial expanded sectional view of the torsional damper of FIG. It is a partial expanded sectional view of FIG. It is a durable performance characteristic diagram of the torsional damper of an Example and a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a perspective view of a torsional damper 1 as an embodiment to which the present invention is applied, FIG. 2 is a partially cutaway perspective view of the torsional damper of FIG. 1, and FIG. 3 is a portion of the torsional damper 1 before press-fitting a rubber member FIG.

  A torsional damper according to the present invention is attached to one end of a rotating shaft (not shown) such as a crankshaft or a camshaft of an engine or the like mounted on a vehicle or the like, and absorbs torsional vibration generated by rotational fluctuation of the rotating shaft. Is. The torsional damper can transmit a part of the engine power transmitted to the engine accessory via the rotating shaft by mounting a belt (not shown) for power transmission.

  The torsional damper 1 according to the present embodiment is fixed to a rotating shaft, and has a hub 2 having an outer peripheral surface that is substantially concentric with the rotating shaft, and an outer peripheral surface that faces the outer peripheral surface of the hub 2 and is substantially concentric with the outer peripheral surface. Inertial ring 3 having an inner peripheral surface, an outer peripheral surface of hub 2 and an annular rubber member 4 press-fitted in a gap between the inner peripheral surface of inertia ring 3.

  Specifically, the hub 2 is formed on the outer periphery of the boss portion 21 to which the tip of the rotating shaft is fixed, the disk-shaped flange portion 24 extending from the boss portion 21 in the outer diameter direction, and the flange portion 24. And a cylindrical portion 25 extending in the axial direction of the rotating shaft, and these are integrally formed of a metal material such as cast iron or a resin material such as phenol resin. As cast iron which comprises hub 2, FC250, FCD450, etc. can be used, for example. The boss portion 21 of the hub 2 is formed with a shaft hole 22 into which the tip of the rotating shaft is inserted and fixed, and a key groove 23. By fastening the tip of the rotating shaft to the boss portion 21, the hub 2 is The rotary shaft is driven to rotate about the central axis C of the rotary shaft. In the present embodiment, the outer peripheral surface 25A of the cylindrical portion 25 of the hub 2 corresponds to the outer peripheral surface that is substantially concentric with the rotating shaft in the present invention.

  The inertia ring 3 is made of a metal material such as cast iron or a composite material of a metal and a resin like the hub 2 and has a predetermined mass so that the torsional damper 1 obtains a predetermined dynamic vibration absorption effect. Yes. As cast iron constituting the inertia ring 3, for example, FC250 or the like can be used. The outer peripheral surface 3B of the inertia ring 3 is formed with a pulley groove 3C on which a belt (not shown) for power transmission to the engine auxiliary machine is hung, and constitutes a power transmission pulley. The inertia ring 3 has a cylindrical shape extending in the axial direction of the rotating shaft, and the inner diameter of the inertia ring 3 is larger than the outer diameter of the hub 2 by a predetermined dimension. By arranging the inertia ring 3 coaxially with the hub 2, the inertia ring inner peripheral surface 3A and the outer peripheral surface 25A of the cylindrical portion 25 of the hub 2 (hereinafter simply referred to as the hub outer peripheral surface 25A) are defined. , Having a predetermined interval and being substantially concentric. As shown in FIG. 3, the gap between the inertia ring inner peripheral surface 3 </ b> A and the hub outer peripheral surface 25 </ b> A is a gap portion 5 into which the rubber member 41 is press-fitted.

  The rubber member 41 press-fitted into the gap portion 5 between the hub 2 and the inertia ring 3 described above reduces torsional vibration of a rotating shaft such as a crankshaft to prevent breakage, and vibration transmitted from the engine, This reduces the noise generated by. The present invention can exhibit the effect of suppressing the generation of wear powder, particularly when a high-damping rubber member excellent in vibration damping effect that easily causes wear is used as the rubber member. In the following description, the rubber member before press-fitting into the gap 5 is referred to as a rubber member 41, and the rubber member after press-fitting is described as 4.

  The torsional damper according to the present invention includes a main compression gap portion that compresses and holds the rubber member by the hub outer circumferential surface and the inertia ring inner circumferential surface, and the hub outer circumferential surface and the inertia as it goes to the end surface of the torsional damper. The inner circumferential surface of the ring is inclined so as to be gradually separated from each other, and the surface roughness of the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring forming the main compression gap and the inclined clearance is 10-point average roughness. (Rzjis) (JIS B0601-1994) 4 μm or more and 30 μm or less, and the hub outer peripheral surface and the inertia ring inner peripheral surface forming the inclined gap, and the hub outer peripheral surface and the inertia ring forming the main compression gap A friction reduction region having a surface roughness smaller than the surface roughness of the peripheral surface is provided.

  In this embodiment, as shown in FIGS. 3 and 4, the gap portion 5 formed between the hub outer peripheral surface 25 </ b> A and the inertia ring inner peripheral surface 3 </ b> A is a main compression gap portion that compresses and holds the rubber member 4. 51 and an inclined gap portion 52 for facilitating the press-fitting operation of the rubber member 41 into the gap portion 5.

The cross section of the main compression gap 51 described above may have a straight shape in which the distance from the rotation shaft is constant from one end to the other end in the press-fitting direction of the rubber member 4, as shown in FIG. The main compression gap 51 may have a concave shape that is recessed in the inner diameter direction or the outer diameter direction in the cross section of the central portion of the rubber member 4 in the press-fitting direction. When the concave shape is employed for the main compression gap 51, it is possible to effectively suppress the disadvantage that the rubber member 4 moves in the direction of coming out of the gap 5 between the hub 2 and the inertia ring 3 due to torsional vibration. . In the main compression gap portion 51 adopting such a cross-sectional shape, the compression rate of the rubber member 4 is not uniform but partially different. For example, as shown in FIG. 4, the main compression gap portion 51 includes areas L _{1 to} L ₃ having different compression ratios, and each area has a gap dimension indicated by t _{1 to} t ₃ . Therefore, as the compression rate of the rubber member 4 in the main compression gap 51 described above, a radial average compression rate calculated by a weighted average in consideration of a partial difference in compression rate was adopted. In the region comprising the recesses (in this case the region L _2), adopt a central thickness in the width direction of the region. This radial direction average compression rate can be expressed by the following formula (1).

ただし、ｔ_０：圧入前のゴム部材の厚み
ｔ_ｎ：空隙部に圧入したときの各領域におけるゴム部材の厚み
Ｌ_０：トーショナルダンパの幅方向の長さ
Ｌ_ｎ：空隙部の各領域の幅方向の長さ
ｎ：圧縮率が異なる領域の数であり、２〜７までの整数。

However, t _0: thickness t n of the rubber member before _press-: thickness of the rubber member in each region when pressed into the gap portion L _0: the width direction of the torsional damper length L _n: each region of the air gap Length in the width direction n: the number of regions having different compression ratios, and an integer from 2 to 7.

Here, one of specific examples when the expression (1) is used will be described with reference to FIG. In FIG. 4, the rubber member 4 press-fitted into the main compression gap portion 51 has thicknesses t ₁ , t ₂ , and t ₃ in the regions L _{1 to} L ₃ having different compression ratios. In the press-fitted rubber member, the thicknesses of the regions L ₄ and L ₅ are t ₄ and t ₅ , respectively. Here, it is assumed that t ₁ ≠ t ₂ ≠ t ₃ ≠ t ₄ ≠ t ₅ . Further, as shown in FIG. 3, the thickness of the rubber member 41 before press-fitting is t ₀ . The radial average compression ratio (%) at this time is shown in the following formula (2).

(Equation 4)
{((T ₀ −t ₁ ) / t ₀ ) × (L ₁ / L ₀ ) + ((t ₀ −t ₂ ) / t ₀ ) × (L ₂ / L ₀ ) + ((t ₀ −t ₃ ) / T ₀ ) × (L ₃ / L ₀ ) + ((t ₀ −t ₄ ) / t ₀ ) × (L ₄ / L ₀ ) + ((t ₀ −t ₅ ) / t ₀ ) × (L ₅ / L ₀ )} × 100 (2)

  At this time, the sum total from the first term to the third term of the above formula (2) is the radial average compression ratio of the main compression gap 51, and the sum from the fourth term to the fifth term is the sum of the inclined gap 52. It is a radial direction average compression rate. As described above, FIG. 4 shows a case where the number of regions having different compression ratios of the main compression gap portion 51 and the inclined gap portion 52 is five in total. In the present invention, when the main compression gap 51 has no recess and the entire main compression gap 51 is uniform, the number of regions having different compression ratios of the main compression gap 51 is n = 1. When the other one of the two inclined gaps 52 does not expand and the main compression gap 51 is formed to be extended, only the other of the inclined gaps 52 has a region having a different compression rate. In the region where the compression ratio of the inclined gap 52 is different, n = 1. Therefore, in such a case, the areas where the compression ratios of the main compression gap 51 and the inclined gap 52 are different are n = 2 in total, and the total number 2 of the areas with different compression ratios is the minimum value. Further, the region where the compression ratio of the main compression gap 51 is different is 3 in the state shown in FIG. 4, and the inclination when each of the two inclined gaps 52 expands with an inflection point. The number of regions having different compression ratios of the gap 52 is n = 2, and the inclined gap 52 is 4 at the maximum. Accordingly, the total number 7 of regions having different compression ratios, which is the sum of the main compression gap 51 and the inclined gap 52, is maximized.

  In addition, it is preferable that the radial direction average compression rate in the main compression gap | interval part 51 of the rubber member 4 mentioned above is 30% or more and 40% or less. By adjusting the amount of compression of the rubber member 4 press-fitted into the main compression gap 51 within a range of 30% or more and 40% or less, the rubber member 4 can be prevented from cracking and a sufficient pressure contact force is imparted. This is because the torsional movement of the member 4 can be prevented.

  The inclined gap 52 is formed at the end of the compression gap 51 in the press-fitting direction of the rubber member 4. The inclined gap 52 is not only the end on the side where the rubber member 4 is press-fitted. , May be provided at both ends. The inclined gap 52 is formed so that the end of the hub outer peripheral surface 25A in the press-fitting direction and the end of the inertia ring inner peripheral surface 3A in the press-fitting direction are end surfaces in the press-fitting direction, that is, the outer peripheral surface 25A. Each of the inclined surfaces 52A and 52B is inclined in a direction away from the inner peripheral surface 3A. The cross-sectional shape of the inclined surfaces 52A and 52B may be a flat surface or a curved surface.

The inclined gap portion 52 compressively holds the end portion of the press-fitted rubber member 4 at both ends of the main compression gap portion 51. The radial compression ratio of the rubber member 4 by the inclined gap portion 52 is preferably 10% or more and 20% or less. Specifically, the radial average compression rate of the rubber member 4 by the inclined gap portion 52 is expressed by the above equation (1), similarly to the radial average compression rate of the rubber member 4 by the main compression gap portion 51 described above. It is preferable that it is 10% or more and 20% or less. As shown in FIG. 4, the inclined gap portion 52 in the present embodiment includes L _{4 to} L ₅ regions where the compression rate decreases outward, and each region is t _{4 to} t _5. It has the gap dimension shown in FIG. Since each region forming the inclined gap portion 52 expands toward the end face with a predetermined inclination, t ₄ and t ₅ are the thickness of the rubber member 4 at the center position in the width direction of each region. .

  At this time, the radial compressive force applied to the rubber member 4 at the end of the rubber member 4 can be increased by setting the average radial compressibility in the inclined gap portion 52 to 10% or more and 20% or less without setting the radial average compression rate to zero. The complete release can be avoided. As a result, a tensile load due to torsional movement is applied to the end of the rubber member 4 to reduce the friction generated between the inclined surfaces 52A and 52B constituting the inclined gap 52, and the end of the rubber member 4 is reduced. It is possible to suppress the inconvenience of generating wrinkles and causing cracks.

  Further, the inclination angle of the inclined surfaces 52A and 52B constituting the inclined gap portion 52, that is, the inclined surface 52A or 52B, and the hub outer peripheral surface 25A or the inertia ring inner peripheral surface 3A constituting the main compression gap portion 51. Is preferably 25 ° or more and less than 40 °. When the inclined surface 52A or 52B is a curved surface, as shown in FIG. 5, the angle θ is determined by the tangent D to the curved surface and the hub outer peripheral surface 25A or the inertia ring inner peripheral surface 3A constituting the main compression gap 51. Is the angle formed by. By setting the inclination angle of each of the inclined surfaces 52A and 52B within the range, the radial compression average of the rubber member 4 in the inclined gap 52 is secured while ensuring the compression area of the rubber member 4 by the main compression gap 51. It can be maintained in the range of 10% or more and 20% or less, and good press-fit workability of the rubber member 4 can be obtained.

  The surface roughness of the outer peripheral surface 25A of the hub and the inner peripheral surface 3A of the inertia ring that forms the gap 5 having the main compression gap 51 and the inclined gap 52 is 10-point average roughness (Rzjis) (JIS). B0601-1994) is 4 μm or more and 30 μm or less, and each of the inclined surfaces 52A, 52B constituting the inclined gap portion 52 has a surface roughness greater than that of the hub outer peripheral surface 25A and the inertia ring inner peripheral surface 3A constituting the main compression gap portion 51. Is provided with a small friction reduction region 53. Note that the friction reduction region 53 means a region where at least the press-fitted rubber member 4 is in close contact, and the friction reduction region 53 may extend over the entire slopes 52A and 53A. The surface roughness is adjusted by surface treatment such as machining or chemical treatment on the outer peripheral surface 25A of the hub or the inner peripheral surface 3A of the inertia ring made of a metal material, a resin material, or a composite material of metal and resin. be able to.

  In the present invention, specifically, the surface roughness of the hub outer peripheral surface 25A and the inertia ring inner peripheral surface 3A of the friction reduction region 53 is 4 μm or more and 15 μm or less in terms of 10-point average roughness (Rzjis) (JIS B0601-1994). The surface roughness of the hub outer peripheral surface 25A and the inertia ring inner peripheral surface 3A other than the friction reduction region 53 is preferably greater than 15 μm and less than 30 μm in terms of 10-point average roughness (Rzjis) (JIS B0601-1994).

  The outer peripheral surface 25A of the hub constituting the inclined gap portion 52, that is, the inclined surface 52A, and the inner peripheral surface 3A of the inertia ring, that is, the inclined surface 52B, the outer peripheral surface 25A of the hub constituting the main compression gap portion 51 and the inner periphery of the inertia ring. The surface of the inclined gap portion 52 is formed by forming a friction reduction region 53 that is smaller than the surface roughness of the surface 3A, for example, a ten-point average roughness (Rzjis) (JIS B0601-1994) of 4 μm to 15 μm. Becomes smooth. Thereby, the frictional resistance between the end portion of the rubber member 4 and the inclined surfaces 52A and 52B in the inclined gap portion 52 can be reduced, and the generation of wear powder of the rubber member 4 caused by the friction between these ends is remarkably suppressed. can do.

  The friction reducing region 53 described above is formed from the main compression gap 51 side to the inclined gap 52 rather than the boundary between the inclined gap 52 and the main compression gap 51 as shown in the partial enlarged view of FIG. Also good. In this case, for example, the friction reduction region 53 is formed closer to the main compression gap 51 than the position where the inclined gap 52 inclined in the direction of expansion from the end of the main compression gap 51 starts, for example, by the dimension d. The Rukoto. As a result, the inflection point where the surface roughness changes from the inflection point of the radial compression rate of the rubber member 4 in the main compression gap 51 and the inclined gap 52 is located closer to the main compression gap 51. The stress applied to the inflection point of the compression rate of the rubber member 4 can be dispersed toward the main compression gap 51. Therefore, cracking of the rubber member 4 due to local stress applied to the rubber member 4 can be more effectively avoided.

  The torsional damper 1 of the present invention has a high damping characteristic in which the loss coefficient (tan δpi) of the rubber member 4 having a surface temperature of 60 ± 5 ° C. during resonance of the torsional damper is greater than 0.23. For this reason, the outstanding vibration reduction effect is produced.

  The torsional damper 1 according to the present invention has a loss coefficient (tan δph) of the rubber member 4 at the surface temperature of 120 ± 5 ° C. at the time of resonance of the torsional damper of 0.21 or more. The loss factor (tan δph) of the rubber member 4 at a surface temperature of 120 ± 5 ° C. at the time of damper resonance and the rubber member 4 at a surface temperature of 60 ± 5 ° C. at the time of torsional damper resonance. The loss factor ratio (tan δph / tan δpi) with respect to the loss factor (tan δpi) is preferably 0.66 or more.

  The loss factor (tan δph) of the rubber member 4 when the surface temperature of the rubber member 4 is 120 ± 5 ° C. during the torsional damper resonance and the rubber member 4 when the surface temperature of the rubber member 4 is 60 ± 5 ° C. during the torsional damper resonance. The loss factor ratio (tan δph / tan δpi) to the loss factor (tan δpi) is an index representing the temperature dependence of the loss factor (tan δ). The loss factor ratio (tan δph) of the rubber member 4 at the time of use at a high temperature and the loss factor (tan δpi) of the rubber member 4 at the time of standard use is large (close to 1) from the use standard temperature. In the present invention, it means that the temperature dependence of the loss factor (tan δ) in the temperature range up to the high temperature is small, that is, the loss factor (tan δ) decreases with temperature change. The loss factor ratio (tanδph / tanδpi) between the loss factor (tanδph) of the rubber member 4 at a temperature of 120 ± 5 ° C and the loss factor (tanδpi) of the rubber member 4 at a surface temperature of 60 ± 5 ° C of the rubber member 4 is 0. Because it is above 66, the loss factor changes with the temperature change of the rubber member in the temperature range from 60 ° C to 120 ° C. Small order, over a range of high temperature side working temperature from using standard temperature, it is found to exhibit excellent vibration absorbing characteristics.

  In the present invention, the shear strain of the rubber member 4 in a state where it is press-fitted into the damper is greater than 35% and less than 60%, and more preferably 45% or more and 55% or less. The shear strain of the rubber member 4 used here corresponds to a relative rubber strain, and in the present invention, it is a value measured by a torque obtained by multiplying the total load torque of the auxiliary machine at a high temperature by a certain safety factor. It is well known that the greater the shear strain, the higher the vibration damping performance. In the present invention, the rubber member 4 having a shear strain of greater than 35% and less than 60% under the above conditions is employed. Even if the rubber member 4 is used for a long period of time while ensuring the predetermined vibration absorption characteristics by setting the shear strain of the rubber member 4 in the range of more than 35% and less than 60% under the above conditions, the wear powder due to the rubber member breakage or rubber wear Occurrence and the like are less likely to occur, and the durability required as a torsional damper can be satisfied. Furthermore, by setting the shear strain of the rubber member 4 under the above conditions to be in the range of 45% or more and 55% or less, higher durability can be realized while ensuring predetermined vibration absorption characteristics.

  Further, the rubber member 41 used in the present invention has a loss coefficient (tan δi) at 60 ° C. of 0.39 or more, and the loss coefficient ratio (tan δh) between the loss coefficient (tan δh) at 120 ° C. and the loss coefficient (tan δi) at 60 ° C. / Tan δi) is preferably 0.87 or more. This is because using such a rubber member 41 for the torsional damper 1 exhibits excellent dynamic vibration absorption from the normal use temperature to a high temperature.

  Moreover, it is preferable that the rubber member 41 used in the present invention has a characteristic that the elongation percentage when the tensile stress of 1.4 MPa is applied to the rubber member 41 a plurality of times is greater than 34% and less than 62%. When the elongation is 34% or less, there is a problem that it is difficult to obtain a desired vibration absorption performance when mounted on a torsional damper. When the elongation is 62% or more, desired durability is obtained at a constant torque. This is because there is a problem that becomes difficult.

  Furthermore, the rubber member 41 used in the present invention preferably has a characteristic that the modulus at 50% elongation is greater than 1.28 MPa and less than 1.82 MPa. When the modulus at 50% elongation is 1.28 MPa or less, it becomes difficult to satisfy the durability required as a torsional damper, and when the modulus at 50% elongation is 1.82 MPa or more, rubber kneading is performed. This is because there is a problem that the property and vulcanization formability deteriorate.

  The rubber member 41 having the above-described characteristics can be realized by, for example, vulcanizing and molding a rubber composition mainly composed of ethylene / propylene / diene ternary copolymer (EPDM) or silicone. Specifically, a rubber composition in which 100 parts by weight or more of carbon black and 40 parts by weight or more of process oil are added to 100 parts by weight of EPDM is added to a predetermined shape (cylindrical in this embodiment) by a well-known method. It can be obtained by sulfur molding. The amount of carbon black greatly affects the loss factor (tan δ) of a rubber member obtained by vulcanizing and molding the rubber composition. When the amount is less than 100 parts by weight with respect to 100 parts by weight of EPDM, the rubber composition is vulcanized. The loss coefficient (tan δ) of the rubber member obtained by molding becomes small, and it becomes difficult to realize the high damping performance as described above.

  In the present invention, the EPDM polymer fraction of the rubber composition is preferably 20% by weight or more and 40% by weight or less. Here, the polymer fraction of EPDM is represented by the following formula (3).

(Equation 5)
EPDM polymer fraction (% by weight) = EPDM polymer parts by weight / total parts by weight × 100 (3)

  When the EPDM polymer fraction is less than 20% by weight, the tackiness of the rubber composition is increased, and the kneadability in the production process is deteriorated. When the EPDM polymer fraction is 40% by weight or more, the loss factor ( tan δ) falls below a desired value.

Moreover, the smaller the particle size of the carbon black contained in the rubber composition described above, the better. The smaller the particle size of the carbon black contained, the greater the loss factor (tan δ) of the rubber member obtained by vulcanization molding of the rubber composition. Moreover, the particle size of the carbon black becomes smaller as the iodine adsorption amount of the carbon black is larger. Therefore, it is preferable to use carbon black having an iodine adsorption amount in the range of 70 mg / g or more and 185 mg / g or less as the carbon black contained in the rubber composition. In addition, the carbon black has a larger structure and higher conductivity as the DBP (plasticizer: dibutyl phthalate) oil absorption of the carbon black increases. black, DBP oil absorption of 40 cm ^3/100 g or more 120 cm ^3/100 g is the use of carbon black in the following ranges preferred. in this way, obtained by vulcanizing a rubber composition comprising the carbon black When the rubber member is attached to the torsional damper, charging of the torsional damper can be prevented and durability can be improved.

  In addition, as a vulcanizing agent used for the rubber composition described above, a peroxide, a co-crosslinking agent, or the like can be used. Specifically, as the 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, ditert-butyl Peroxide, dicumyl peroxide, N-butyl-4,4-di (tert-butylperoxy) valerate, tert-butylcumyl peroxide and the like can be used.

  As the co-crosslinking agent, triallyl isocyanate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, quinone dioxime, 1,2-polybutadiene, and the like can be used.

  In addition to the components described above, the rubber composition can contain a process oil (mineral oil), a plasticizer, zinc white, zinc stearate, an anti-aging agent and the like as known rubber additives. .

  With the above configuration, when the torsional damper 1 is manufactured, the hub 2 and the inertia ring 3 are arranged substantially concentrically on a support base (not shown), and as shown in FIG. A cylindrical rubber member 41 is press-fitted into the gap 5. At this time, since the gap 5 is formed to be narrower than the thickness of the rubber member 41 in the radial direction, the rubber member 41 is pressed into the gap 5 while being compressed using a jig (not shown).

  Furthermore, in the present invention, an inclined gap portion 52 that is expanded outward is formed at the end portion in the press-fitting direction of the gap portion 5, so that the gap size is larger than that of the main compression gap portion 51. The rubber member 41 can be smoothly press-fitted along the inclined gap portion 52. In particular, the hub outer peripheral surface 25A and the inertia ring inner peripheral surface 3A forming the inclined gap 52 in the present invention have a surface roughness that is greater than that of the hub outer peripheral surface 25A and the inertia ring inner peripheral surface 3A forming the main compression gap 51. For example, a rubber member having a high damping characteristic that easily causes wear is used because the friction reduction region 53 is small, for example, a ten-point average roughness (Rzjis) (JIS B0601-1994) of 4 μm or more and less than 15 μm. Even in this case, it is possible to effectively suppress the occurrence of cracks in the rubber member 4 due to wrinkles and the like during press-fitting work, and by using a rubber member having an excellent vibration damping effect, the vibration damping effect It is possible to realize a torsional damper that is excellent in durability and high durability.

  Further, the rubber member 4 press-fitted into the gap portion 5 between the inertia ring 3 and the hub 2 causes a torsional movement that is shifted in the circumferential direction between the inertia ring 3 and the hub 2. Since the main compression gap 51 is compressed and held by the hub outer peripheral surface 25A and the inertia ring inner peripheral surface 3A, torsional movement is suppressed. In particular, in the present invention, the surface roughness of the outer peripheral surface 25A of the hub and the inner peripheral surface 3A of the inertia ring in the main compression gap 51 other than the friction reduction region 53 described above is the inclined surfaces 52A, 52B constituting the inclined gap 52. By setting a larger roughness, for example, a ten-point average roughness (Rzjis) (JIS B0601-1994) to be larger than 15 μm and not larger than 30 μm, the rubber member 4 and the outer peripheral surface 25A and the inner peripheral surface 3A in the main compression gap 51 are formed. Therefore, the torsional movement can be suppressed.

  Further, the surface roughness of the friction reduction region 53 formed in the inclined gap portion 52 of the gap portion 5 between the hub 2 and the inertia ring 3 is smaller than that of the main compression gap portion that compresses and holds the rubber member 4, for example, ten points. The average roughness (Rzjis) (JIS B0601-1994) is 4 μm or more and 15 μm or less. Therefore, even if the rubber member 4 held in the inclined gap 52 is twisted and moved, the inclined surfaces 52A and 52B constituting the inclined gap 52 and the rubber member 4 are rubbed and worn out. It can be remarkably solved. For this reason, even when a rubber member having a high damping characteristic that easily causes wear is used, wear powder is generated by friction between the rubber member 4 and the inclined surfaces 52A and 52B constituting the inclined gap portion 52. The inconvenience which generate | occur | produces can be suppressed effectively, and the inconvenience which a crack and a crack generate | occur | produce in the said rubber member 4 can be suppressed remarkably simultaneously.

  Examples of the present invention will be described below.

1. Production and evaluation of rubber member for torsional damper (1) Adjustment process of rubber composition In Examples 1 to 3, first, 100 parts by weight of EPDM was put into a Banbury mixer and masticated at a rotational speed of 40 rpm for 1 minute. , 140 parts by weight of carbon black, 70 parts by weight of process oil, 5 parts by weight of zinc oxide, 1 part by weight of zinc stearate and 2 parts by weight of anti-aging agent were added and kneaded for 2 minutes, and further kneaded for 1 minute, Was removed from the Banbury mixer. Subsequently, the kneaded product taken out was wound around a 12-inch roll with a roll interval of 5 mm and formed into a sheet, and the formed dough was left at room temperature for 12 hours or more. Here, carbon black is the iodine adsorption amount 110 mg / g, DBP oil absorption amount using carbon black as a 70cm ^3/100 g. Incidentally, the iodine adsorption of ± 7 mg / g, DBP oil absorption has a tolerance of ± ^7cm 3 / 100g.

  Next, the above-mentioned dough is wound around a 6-inch roll with a roll interval of 4 mm, and 3.5 parts by weight of 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane as a peroxide and a co-crosslinking agent. After kneading 2 parts by weight of trimethylolpropane trimethacrylate as above, turning back and forth 3 times each, rounding 5 times, and then forming into a sheet.

  Example 1 and Example 2 had the same conditions except that the EPDM used was different. That is, the commercially available EPDM used was different in ethylene weight ratio and oil-extended oil amount. In Example 1, oil-extended EPDM was used, and in Example 2, non-oil-extended EPDM was used. Example 3 was the same as Example 1 except that 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane as a peroxide was 2.5 parts by weight. The composition ratios and EPDM polymer fractions of the rubber compositions of Examples 1 to 3 are shown in Table 1 described later together with the evaluation. At this time, the amount of process oil to be added was adjusted in consideration of the amount of oil-extended oil contained in commercially available EPDM, and the above-mentioned weight ratio was obtained.

  Specifically, the EPDM in Example 1 was prepared by mixing a first grade having an ethylene weight ratio of 55% or less and an oil-extended grade having an oil-extended oil amount of 40 parts by weight or more to an ethylene weight ratio of 58%. At this time, the relationship between the respective weight parts of the first grade (1G), the oil-extended grade (OG), and the process oil amount (PO, the amount obtained by subtracting the oil contained in the oil-extended grade polymer) is as follows. .

  That is, when the addition amount (parts by weight) of the first grade (1G) is A, and when the total weight part of the polymer and oil-extended oil is D when the oil-extended grade EPDM polymer used is 100 parts by weight, the oil The addition amount (parts by weight) B of the spreading grade (OG) is (100−A) × D / 100. Moreover, the addition amount (parts by weight) C of the process oil when the oil-extended grade (OG) is used is (process oil addition amount when the oil-extended EPDM is not used) − (A + B−100). Here, when blending and using oil-extended EPDM grades, it is converted so that the total of EPDM polymer of the first grade and EPDM polymer excluding oil-extended oil of oil-extended EPDM grade is 100 parts by weight. Show.

  Thus, by using an oil-extended grade polymer, the amount of process oil added during kneading can be suppressed, the dispersibility of carbon black can be improved, and the tensile strength and elongation can be improved.

(2) Rubber composition vulcanization step Next, the dough obtained in the above rubber composition adjustment step is housed in a mold, and press vulcanized at 180 ° C for 10 minutes to give a rubber having a thickness of 2 mm. A sheet was prepared, and further heat-treated for 6 hours in a thermostatic bath at 150 ° C.

  Moreover, the rubber member (test piece) of the comparative example 1 and the comparative example 2 which are shown in Table 1 by the same method except having changed the composition ratio of the torsional damper rubber composition was produced. The rubber compositions before vulcanization used in Examples 1 to 3 and Comparative Examples 1 to 2 are referred to as Composition 1 to Composition 3 and Comparative Composition 1 to Comparative Composition 2, respectively. Moreover, the rubber member formed by carrying out the vulcanization molding by the composition 1-the composition 3, the comparative composition 1-the comparative composition 2, and the test piece 1-the test piece 3, the comparative test piece 1-the comparative test piece 2 and To do. In Comparative Example 2, 3.5 parts by weight of a peroxide (dicumyl peroxide) different from Examples 1 to 3 and Comparative Example 1 was used.

(3) Evaluation of rubber members (test piece 1 to test piece 3, comparative test piece 1 to comparative test piece 2) a) Evaluation of loss factor (tan δi, tan δh) and loss factor ratio (tan δh / tan δi) Loss at 60 ° C The coefficient (tan δi), the loss coefficient at 120 ° C. (tan δh), and the loss coefficient ratio between 120 ° C. and 60 ° C. (tan δh / tan δi) were measured according to JIS K6394 under the following conditions. The measurement results are shown in Table 1.
<Measurement conditions>
Measuring instrument: Viscoelastic analyzer YR-7130 manufactured by Ueshima Seisakusho
・ Deformation method: Tensile ・ Frequency: 100 Hz
・ Amplitude: ± 1%
・ Preload: 480mN
-Test piece shape: It collected from the sheet-like rubber member after vulcanization molding.
20mm (grip interval) x 4mm (width) x 2mm (thickness) strip-shaped piece

b) Evaluation of hardness Based on JIS K6253, the durometer A was used and the hardness of the rubber member was measured by the method read within 1 second. The measurement results are shown in Table 1.

c) Evaluation of Tensile Strength, Elongation Rate and Modulus According to JIS K6251, the modulus at 50% extension, the modulus at 300% extension, the modulus at 300% extension / the modulus ratio at 50% extension were measured. In addition, the shape of a test piece is dumbbell-shaped No. 5. The measurement results are shown in Table 1.

d) Elongation rate when stress is 1.4MPa (%)
Rubber elongation (%) was evaluated when repeated stress was applied multiple times under the following measurement conditions. The measurement results are shown in Table 1.
<Measurement conditions>
・ Tensile speed: 100 mm / min
Stress application method: after sweeping from 0 MPa to 1.4 MPa, returning to 0 MPa again, sweeping again to 1.4 MPa, and repeating this about 10 to 50 times.
-Specimen shape: Dumbbell shape No. 5 (conforms to JIS K 6251)

2. Manufacture and evaluation of torsional damper (1) Manufacture of torsional damper Rubber member for annular damper having the same composition as the rubber members (test piece 1 to test piece 3, comparative test piece 1 to comparative test piece 2) described above ( A rubber member 41) shown in FIG. 3 was prepared and press-fitted into the gap 5 between the hub 2 and the inertia ring 3 to produce torsional dampers of Examples 1a to 3a and Comparative Examples 1a to 2a.

  At this time, the hub 2 and the inertia ring 3 were made of the cast iron, phenol resin, or composite material of metal and resin described above. The average radial compression ratio of the rubber member 4 in the gap 5 between the hub 2 and the inertia ring 3 is 30% to 40% in the main compression gap 51 and 10% to 20% in the inclined gap 52. Adjusted. The inclination angle of the inclined gap portion 52 at this time is set to 25 ° to 35 °, and the ten-point average roughness of the hub outer peripheral surface 25A and the inertia ring inner peripheral surface 3A constituting the main compression gap portion 51 and the inclined gap portion 52 ( Rzjis) (JIS B0601-1994) were all in the range of more than 15 μm and 30 μm or less.

(2) Evaluation of torsional damper a) Evaluation of loss factor (tan δpi, tan δph) and loss factor ratio (tan δph / tan δpi) The loss factor (tan δpi), the loss factor (tan δph) of the rubber member 4 at a surface temperature of 120 ± 5 ° C., and the loss factor ratio (tan δph / tan δpi) are determined by a resonance sweep method (natural frequency) using a high-frequency vibration tester. Measurement) was performed under the following conditions using a non-contact surface thermometer. The measurement results are shown in Table 1.
<Measurement conditions>
・ Rubber member surface temperature: 60 ± 5 ℃, 120 ± 5 ℃
Excitation amplitude: ± 1.7 × 10 ⁻³ rad (± 0.1 °)
・ Sweep speed: 100Hz / min

b) Evaluation of shear strain (%) The shear strain (rubber strain during the durability test) (%) of the rubber member 4 is the amount of deformation in the circumferential direction of the annular rubber member when a constant amplitude is given. The value obtained by multiplying the value divided by the thickness by 100. In this example, the measurement was performed under the following test conditions. The vibration amplitude (load torque) under the following conditions is the total load torque applied to auxiliary equipment such as an air conditioner, alternator, and water pump connected to the pulley groove 3C (pulley part) of the torsional damper via a belt. It is a value obtained by multiplying the measured torque by a certain safety factor. The measurement results are shown in Table 1.
<Measurement conditions>
・ Ambient temperature: 100 ± 3 ℃
・ Excitation amplitude (load torque): ± 180 N / m
・ Excitation frequency: 10Hz

c) Evaluation of Constant Torque Durability The constant torque durability is evaluated by measuring the shearing force of the rubber member 4 up to 1.0 × 10 ⁷ times using a method for measuring the shear strain of the rubber member 4. The change in shear strain (%) was measured and confirmed. FIG. 6 shows a durability performance characteristic diagram of the torsional damper obtained in the evaluation of the constant torque durability. In Table 1 described above, the constant torque durability evaluation result is “◎” when there is no abnormality in the appearance of the rubber member 4 after the specified number of tests, and deformation is confirmed in the appearance of the rubber member 4 after the specified number of tests. “○” indicates that the rubber member 4 was damaged, and “X” indicates that the rubber member 4 was damaged by the specified number of tests.

d) Evaluation of rubber wear powder The rubber wear powder was evaluated under the following conditions, and the degree of occurrence of the rubber wear powder was visually confirmed.
<Measurement conditions>
-Rubber shear strain: ± 45% (rubber twist angle = ± 1.59 deg.)
・ Ambient temperature: 23 ± 3 ℃
・ Excitation frequency: 30Hz
・ Number of tests: 7.7 × 10 ⁶ times

  In Table 1 above, the result of the degree of rubber wear powder generation is “○” when the amount of wear powder adheres very little after the specified number of tests, and a small amount of wear powder adheres after the specified number of tests. “△” was used, and “×” was the case where a large amount of wear powder was confirmed after the prescribed number of tests.

e) Relationship between shear strain of rubber member press-fitted into torsional damper and rubber wear powder As shown in FIG. 6, the rubber member 4 of the torsional damper of Comparative Example 1a is Since the rubber member has a shear strain of 35%, almost no generation of wear powder was confirmed. Further, the rubber member of Comparative Example 2a using the rubber member 4 in which the shear strain of the rubber member 4 is 60% with respect to a constant load torque is broken before reaching the specified number of tests, and a large amount of wear powder is generated. Had occurred. On the other hand, since the shear strain of the rubber member of the torsional damper of Examples 1 to 3 has an appropriate rubber shear strain for a constant load torque of 45% to 55%, the specified number of tests The rubber member 4 was not broken until the end, but a small amount of rubber abrasion powder was generated.

  Therefore, in order to suppress the generation of rubber wear powder in the durability evaluation as much as possible, the rubber member 41 manufactured using the rubber composition of Examples 1 to 3 in Table 1 described above is pressed into the torsional damper. Ten points on the surfaces of the inclined surfaces 52A and 52B constituting the inclined gap portion 52 formed by the hub outer peripheral surface 25A of the torsional damper and the inner peripheral surface 3A of the inertia ring, which are considered to be the cause of the generation of rubber wear powder. The average roughness (Rzjis) (JIS B0601-1994) was changed from 4 μm to 15 μm, and the occurrence of rubber wear powder was examined. Table 2 below shows the results of a rubber wear powder confirmation test in which the surface roughness of each of the inclined surfaces 52A and 52B is changed. In Table 2, the meanings of the evaluation results of “◯”, “Δ”, and “×” of “Abrasion powder generation degree” are the same as those in Table 1.

  In Table 2, Comparative Example 3a to Comparative Example 5a are comparative for confirming the state of rubber friction powder generation by changing the surface roughness of the inclined gap portion 52, and are the same as those of Examples 1 to 3. The rubber member was used. Comparative Example 3a to Comparative Example 5a have the same radial average compression ratio and ten-point average roughness (Rzjis) (JIS B0601-1994) of Example 1a to Example 3a, and the inclined gap portion. The only difference is that the 10-point average roughness (Rzjis) (JIS B0601-1994) of each of the inclined surfaces 52A and 52B constituting 52 is set to 20 μm.

  From Table 2, it can be grasped that the wear powder tends to decrease as the surface roughness of the inclined surfaces 52A and 52B constituting the inclined gap portion 52 is smaller. Therefore, by forming the inclined surfaces 52A and 52B constituting the inclined gap portion 52 so that the ten-point average roughness (Rzjis) (JIS B0601-1994) is 4 μm or more and 15 μm or less, a rubber member having a small shear strain is formed. It turns out that generation | occurrence | production of abrasion powder can be suppressed similarly to the case where it uses.

  From the above, the surface roughness of the inclined gap portion of the press-fitting inlet portion of the gap portion 5 is smaller than that of the main compression gap portion that compresses and holds the rubber member 4, for example, ten-point average roughness (Rzjis) (JIS B0601). -1994), the loss coefficient (tan δpi) at the surface temperature of the rubber member 4 at 60 ° C. during the damper resonance is 0.23 or more, and the shear strain of the rubber member 4 is 45% or more and 55. Even if it is a rubber member with a high damping characteristic of less than 10%, it is possible to effectively suppress the inconvenience that abrasion powder is generated due to friction with each inclined surface constituting the inclined gap portion, and the inconvenience that wrinkles and cracks are generated. It can be said that it can be remarkably suppressed. Thus, by smoothing the surface roughness of the inclined gap portion, it can be said that the predetermined vibration isolating characteristics can be maintained for a long period of time using a rubber member having a high damping characteristic that easily wears.

  In the above-described embodiment, the case where the torsional damper is attached to the crankshaft or the camshaft is described. However, the present invention is not limited to this, and torsional vibrations on various rotating shafts are described. It can be applied to reduce. Furthermore, the rubber member exhibiting high damping performance in the present invention can be used for various applications other than the torsional damper used in vehicles and the like.

  In the torsional damper according to the present invention, the surface roughness of the gap portion between the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring is 4 μm or more and 30 μm or less, and the surface roughness of the inclined gap portion of the gap portion is rubber. Since the surface roughness of the main compression gap that compresses and holds the member is smaller, wear in the inclined gap is less likely to occur, durability is better than conventional rubber members, and when using a rubber member with high damping characteristics Is particularly useful.

DESCRIPTION OF SYMBOLS 1 Torsional damper 2 Hub 3 Inertial ring 3A Inner peripheral surface 3B Outer peripheral surface 3C Pulley groove (pulley part)
4 Rubber member (after press fitting)
5 Gap part 21 Boss part 22 Shaft hole 23 Key groove 24 Flange part 25 Cylindrical part 25A Outer peripheral surface (hub outer peripheral surface)
41 Rubber member (before press fitting)
51 Main compression gap 52 Inclination gap 52A, 52B Inclined surface 53 Friction reduction region

Claims (11)

A hub that is fixed to the rotating shaft and has an outer peripheral surface that is substantially concentric with the rotating shaft; an inertia ring that is opposed to the outer peripheral surface of the hub and has an inner peripheral surface that is substantially concentric with the outer peripheral surface; A torsional damper including a rubber member press-fitted into a gap between the surface and the inner peripheral surface of the inertia ring,
The loss factor (tan δpi) of the rubber member at a surface temperature of 60 ± 5 ° C. at the time of resonance of the torsional damper is greater than 0.23, and the measurement is performed with the total load torque of the auxiliary machine at a high temperature. The shear strain of the rubber member when pressed into the torsional damper is greater than 35% and less than 60%,
The gap portion includes a main compression gap portion that compresses and holds the rubber member formed by the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring, and an end portion of the hub outer peripheral surface and an inner peripheral surface end portion of the inertia ring. Formed with an inclined gap portion inclined in a direction in which the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring are separated from each other toward the end surface;
The outer peripheral surface of the hub and the inner peripheral surface of the inertia ring that form the main compression gap portion and the inclined gap portion are 4 μm or more and 30 μm or less, and the outer peripheral surface of the hub and the inertia ring that form the inclined gap portion. A torsional damper comprising a hub outer peripheral surface forming the main compression gap portion and a friction reduction region having a smaller surface roughness than the inner peripheral surface of the inertia ring on the inner peripheral surface.   The surface roughness of the outer peripheral surface of the hub and the inner peripheral surface of the inertia ring in the friction reduction region is 4 μm or more and 15 μm or less, and the surface roughness of the outer peripheral surface of the hub other than the friction reduction region and the inner peripheral surface of the inertia ring is 15 μm. The torsional damper according to claim 1, wherein the torsional damper is larger than 30 μm. The radial average compression ratio of the rubber member represented by the following formula (1) is defined by the average compression ratio of the main compression gap and the average compression ratio of the inclined gap, and the main compression gap is 30. 3. The torsional damper according to claim 1, wherein the inclination gap is 10% or more and 20% or less.

However, t _0: thickness t n of the rubber member before _press-: thickness of the rubber member in each region when pressed into the gap portion L _0: the width direction of the torsional damper length L _n: each region of the air gap Length in the width direction n: the number of regions having different compression ratios, and an integer from 2 to 7.   The torsional damper according to any one of claims 1 to 3, wherein an inclination angle of the inclined gap portion is 25 ° or more and less than 40 °.   The torsional damper according to any one of claims 1 to 4, wherein an elongation rate when a tensile stress of 1.4 MPa is applied to the rubber member before press-fitting a plurality of times is greater than 34% and less than 62%. . The loss coefficient (tan δph) of the rubber member at a surface temperature of 120 ± 5 ° C. at the time of torsional damper resonance is 0.21 or more,
The loss factor (tan δph) of the rubber member when the surface temperature of the rubber member is 120 ± 5 ° C. during the torsional damper resonance and the rubber member when the surface temperature of the rubber member is 60 ± 5 ° C. during the torsional damper resonance 6. The torsional damper according to claim 1, wherein a loss factor ratio (tan δph / tan δpi) to a loss factor (tan δpi) is 0.66 or more.   The rubber member before press-fitting has a loss coefficient (tan δi) at 60 ° C. of 0.39 or more, and a loss coefficient ratio (tan δh / tan δi) between a loss coefficient (tan δh) at 120 ° C. and a loss coefficient (tan δi) at 60 ° C. The torsional damper according to any one of claims 1 to 6, wherein the torsional damper is 0.87 or more.   The torsional damper according to any one of claims 1 to 7, wherein a modulus at 50% elongation of the rubber member before press-fitting is greater than 1.28 MPa and less than 1.82 MPa. The rubber member before press-fitting is obtained by vulcanization molding of a rubber composition,
2. The rubber composition is added with 100 parts by weight or more of carbon black and 40 parts by weight or more of process oil with respect to 100 parts by weight of EPDM, and the polymer fraction of the EPDM is 20% by weight or more and 40% by weight or less. The torsional damper according to any one of claims 8 to 9.   The torsional damper according to claim 9, wherein the carbon black has an iodine adsorption of 70 mg / g or more and 185 mg / g or less. Torsional damper according to any one of the carbon black DBP oil absorption of 40 cm ^3/100 g or more 120 cm ^3/100 g or less is claim 8 according to claim 10.

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