JP3582536B2 - Torque fluctuation absorption damper - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a torque fluctuation absorbing damper that absorbs and insulates the fluctuation of the transmission torque of the crankshaft due to each stroke of the engine when transmitting the power of the engine crankshaft to various auxiliary devices.
[0002]
[Prior art]
Conventionally, as shown in FIG. 2, this type of torque fluctuation absorbing damper has a torsion displacement (displacement in the direction around the axis) on the outer periphery of a hub 101 attached to the tip of an engine crankshaft via a bearing 102a. A coupling portion 102 having a structure in which pulleys 102b arranged freely and concentrically are connected via an elastomer member 102c is provided (for example, see Japanese Utility Model Application Laid-Open No. 63-68540). That is, a part of the power of the crankshaft is supplied to various auxiliary devices such as an alternator and a compressor through an endless belt (not shown) wound around the pulley 102b. The coupling part 102 absorbs and insulates the torque fluctuation between the pulley 102b and the pulley 102c by the torsional deformation of the elastomer member 102c, thereby smoothing the transmission torque from the pulley 102b.
[0003]
Further, on the outer periphery of the hub 101, a torsion damper portion 103 having a structure in which an annular mass body 103b is elastically connected via another elastomer member 103a is arranged in parallel. The torsion damper section 103 resonates so as to cancel the torsional vibration of the crankshaft in a predetermined frequency range, and exhibits a vibration damping function of reducing the torsional vibration itself of the crankshaft.
[0004]
Incidentally, the natural frequency in the torsional direction of the coupling portion 102 is determined by the fact that the inertial mass of the pulley 102b is large and the spring constant of the elastomer member 102c is lower than that of the elastomer member 103a of the torsional damper portion 103. It is considerably lower than the natural frequency in the torsional direction of the crankshaft.For example, since it is in the region below the frequency of the torque fluctuation of the crankshaft during idling, the crankshaft of The frequency of the torque fluctuation passes through the natural frequency range of the coupling section 102 in the torsional direction. If the pulley 102b is largely displaced in the torsional direction with respect to the hub 101 due to the resonance of the coupling portion 102 at this time, the elastomer member 102c may be damaged due to excessive deformation. Usually, a stopper 104 for limiting the relative displacement of the hub 101 and the pulley 102b in the torsional direction is provided. As shown in FIG. 3, the stopper 104 has a metal ring 104a fixed to the hub 101 and having irregularities on the outer periphery, and has a concave and convex fixed on the pulley 102b side and loosely fitted with the irregularities on the inner periphery. And a metal ring 104b.
[0005]
[Problems to be solved by the invention]
According to the above-described conventional torque fluctuation absorbing damper, the amount of vibration displacement of the pulley 102b due to resonance of the coupling portion 102, in other words, the amount of torsional deformation of the elastomer member 102c is determined by the interference between the irregularities of the metal rings 104a and 104b at the stopper 104. Because of the limitation to the predetermined range, a problem that a metal hitting sound occurs at the time of resonance is pointed out.
[0006]
The present invention has been made under the circumstances described above, and its main technical problem is to effectively prevent excessive deformation of an elastomer member without generating a tapping sound at the time of resonance of a coupling portion. Is to prevent it.
[0007]
[Means for Solving the Problems]
The technical problem described above can be effectively solved by the present invention.
That is, the torque fluctuation absorbing damper according to the present invention includes a coupling portion in which a pulley is connected to an outer periphery of a hub attached to a crankshaft of an engine via a first elastomer member so as to be capable of torsional displacement, and an inner periphery of the pulley. A structure in which the annular mass body is connected to the outer periphery of the hub via a second elastomer member arranged in the axial direction with the first elastomer member so as to be capable of torsional displacement, and has a natural frequency different from that of the coupling portion. And a viscous fluid sealed in a gap formed between the first elastomer member and the torsional damper portion and between the pulley side and the torsional damper portion.
In the present invention, more preferably, the gap is closely fitted to the inner peripheral surface of the pulley and extends radially along the side surface of the torsional damper portion; And a seal member slidably interposed therebetween. Further, the gap communicates with an intervening portion of the sliding bearing between the inner peripheral surface of the pulley and the outer peripheral surface of the annular mass body.
[0008]
[Action]
The increase in the amount of vibration displacement of the pulley when the coupling portion resonates in the torsional direction is caused by the difference between the pulley side that is repeatedly torsional displaced and the torsional damper portion that does not resonate at the resonance frequency of the coupling portion. It is suppressed by the damping action due to the viscous resistance of the viscous fluid subjected to shearing in the gap. In particular, a partition plate closely fitted to the inner peripheral surface of the pulley and extending radially toward the hub along the side surface of the torsion damper portion, and slidably slidably between the inner diameter of the partition plate and the hub. With the interposed seal member, the distance between the surfaces relatively displaced in the torsional direction on both sides of the gap can be reduced, the friction area with the viscous fluid can be increased, and the braking action by viscous damping can be enhanced. In addition, the sliding bearing is lubricated by connecting the gap to an interposed portion of the sliding bearing that supports the pulley concentrically on the outer periphery of the annular mass body of the torsional damper portion.
[0009]
Further, since the coupling portion does not resonate when the torsional damper portion resonates, the damping due to the internal friction of the second elastomer member in the torsional damper portion also occurs in the torsional vibration damping of the crankshaft due to the resonance of the torsional damper portion. In addition, damping due to viscous resistance generated by the shearing of the viscous fluid between the pulley side of the coupling portion and the torsional damper portion torsionally displaced relative thereto is obtained.
[0010]
【Example】
FIG. 1 shows an embodiment of a torque fluctuation absorbing damper according to the present invention, which is cut along a plane passing through its axis. Reference numeral 1 denotes a hub attached to the shaft end of a crankshaft of an engine. On the outer periphery of the hub 1, a coupling portion 2 to which a pulley 22 is connected via a first elastomer member 21 so as to be capable of torsional displacement, and an annular mass body 32 via a second elastomer member 31 to be capable of torsional displacement. A torsional damper section 3 having a connected structure is provided.
[0011]
The hub 1 has a substantially L-shaped cross section having a radial portion 11 that is a portion to be attached to a crankshaft and an outer diameter cylindrical portion 12 extending from the outer diameter. A large-diameter V-pulley groove 22a and a small-diameter V-pulley groove 22b are formed on the outer peripheral surface of the pulley 22, and the inner peripheral surface of the pulley 22 correspondingly has a large-diameter on the V-pulley groove 22a side and the other. The V-pulley groove 22b side is formed in a stepped shape with a small diameter. The first elastomer member 21 has a sleeve 23 fitted on the outer peripheral surface of the outer cylindrical portion 12 of the hub 1 near the radial portion 11 and a large-diameter inner peripheral surface of the pulley 22 on the V-pulley groove 22a side. It is vulcanized and formed integrally with the fitted sleeve 24. The annular mass body 32 is disposed on the inner periphery of the pulley 22 on the side of the small-diameter V-pulley groove 22b, and the second elastomer member 31 is located on the side opposite to the radial portion 11 of the outer diameter cylindrical portion 12 of the hub 1. Is vulcanized and formed integrally between the sleeve 33 fitted on the outer peripheral surface near the end and the annular mass body 32. A sliding bearing 4 made of a synthetic resin material is slidably interposed between the opposed peripheral surfaces of the annular mass body 32 and the pulley 22.
[0012]
Between the hub 1 and the pulley 22 and between the first elastomer member 21 and the torsional damper unit 3, the inner surface of the annular mass body 32 and the second elastomer member 31 of the torsional damper unit 3 (the A partition plate 5 extending in the radial direction is arranged near the one elastomer member 21 side), and the outer diameter end of the partition plate 5 is closely fitted to the inner peripheral surface of the pulley 22. A seal member 6 slidable in the circumferential direction is interposed between the inner diameter end portion of the partition plate 5 and the outer diameter cylindrical portion 12 of the hub 1. An outer diameter portion of the annular mass body 32 is formed with a flange portion 32a extending to an outer diameter side between a radial step surface 22c formed on an inner peripheral surface of the pulley 22 and the partition plate 5.
[0013]
Between the pulley 22 side and the torsion damper portion 3, more specifically, a radial step surface 22c on the inner peripheral surface of the pulley 22, the partition plate 5 closely fitted to the large-diameter inner peripheral surface of the pulley 22, and the inner diameter thereof A narrow gap 7 in which a viscous fluid 8 is sealed is formed between the seal member 6 that seals between the end and the hub 1, and the annular mass body 32 including the flange 32 a and the second elastomer member 31. ing. One end of the gap 7 communicates with an intervening portion of the slide bearing 4, and the outside of the slide bearing 4 is fitted to the small-diameter inner peripheral surface of the pulley 22 and is slidable on the outer peripheral surface of the annular mass body 32. Is sealed by an oil seal 9 which is in close contact.
[0014]
In the figure, reference numeral 32b denotes an injection hole for the viscous fluid 8 into the gap 7, and 32c denotes a sphere formed by sealing the injection hole 32b after the injection of the viscous fluid 8.
[0015]
In the torque fluctuation absorbing damper according to this embodiment, the natural frequency in the torsional direction of the coupling portion 2 is in the region below the frequency of the torque fluctuation of the crankshaft during the idle rotation of the engine, as described above. Since the torsional damper portion 3 is for absorbing torsional vibration of the crankshaft in a relatively high-speed rotation range, its natural frequency in the torsional direction is higher than that of the coupling portion 2. . Therefore, when the engine is started, in the process from cranking to idling, the coupling portion 2 resonates with the low-frequency torque fluctuation of the crankshaft, and the pulley 22 is largely displaced in the torsional direction with respect to the hub 1 by vibrating displacement. Although the amount of torsional displacement of the first elastomer member 21 increases, the torsional damper portion 3 does not resonate. Therefore, between the pulley 22 and the partition plate 5 that is repeatedly displaced in the torsional direction integrally therewith, The viscous fluid 8 in the gap 7 is subjected to shearing. At this time, the amplitude of the torsional displacement of the pulley 22 is suppressed by viscous resistance, and the amount of torsional displacement of the first elastomer member 21 is limited. Also, in a high-speed rotation region where the torsional damper unit 3 resonates and absorbs torsional vibration of the crankshaft, the coupling unit 2 does not resonate. In this case, too, the viscous fluid 8 in the gap 7 is subjected to shearing. Damping by viscous resistance of the viscous fluid 8 is obtained in addition to damping by internal friction of the second elastomer member 31 of the directional damper unit 3.
[0016]
The gap 7 in which the viscous fluid 8 is sealed has a narrow width between opposing surfaces on both sides thereof, and has a flange portion 32a formed on the annular mass body 32 and a radial step between the partition plate 5 and the pulley 22 on both axial sides thereof. Since the shape is largely folded in the radial direction by the surface 22c, the friction surface with the viscous fluid 8 is large. Therefore, a large damping force effective for suppressing the amplitude of the torsional displacement of the pulley 22 is obtained.
[0017]
The sliding bearing 4 made of a synthetic resin supports the pulley 22 on the outer periphery of the annular mass body 32 of the torsion damper unit 3 so as to be concentric and freely torsional displacement. The wear tends to increase. However, in this embodiment, the sliding bearing 4 is lubricated by the viscous fluid 8 sealed in the gap 7, so that it is less susceptible to wear and its durability is improved.
[0018]
【The invention's effect】
According to the present invention, the following effects are realized.
(1) When the coupling portion resonates in the torsional direction, the increase in the amount of vibration displacement of the pulley is suppressed by viscous damping action of the viscous fluid, so that the coupling portion does not generate interference noise as in the case where a stopper is provided. Large deformation of the first elastomer member is effectively prevented.
(2) The sliding bearing that concentrically supports the pulley on the outer periphery of the annular mass body of the torsional damper is lubricated with a viscous fluid, so that its durability is improved.
(3) Due to the viscous damping of the viscous fluid, the vibration damping force of the torsional damper part is improved.
[Brief description of the drawings]
FIG. 1 is a half sectional view showing an embodiment of a torque fluctuation absorbing damper according to the present invention by cutting along a plane passing through an axis thereof.
FIG. 2 is a half sectional view showing an example of a conventional torque fluctuation absorbing damper cut along a plane passing through an axis thereof.
FIG. 3 is a partial cross-sectional view showing the above-described conventional example cut along a line III-III in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hub 11 Radial direction part 12 Outer diameter cylindrical part 2 Coupling part 21 First elastomer member 22 Pulley 22a, 22b V pulley groove 23, 24, 33 Sleeve 3 Torsional damper part 31 Second elastomer member 32 Ring mass Body 4 Bearing 5 Partition plate 6 Seal member 7 Gap 8 Viscous fluid 9 Oil seal

Claims (3)

A coupling portion (2) in which a pulley (22) is connected to the outer periphery of a hub (1) attached to the crankshaft of the engine via a first elastomer member (21) so as to be capable of torsional displacement;
An annular mass body (32) arranged on the inner periphery of the pulley (22) is provided on the outer periphery of the hub (1) with a second elastomer member (31) arranged in the axial direction with the first elastomer member (21). A torsional displacement damper section (3) having a natural frequency different from that of the coupling section (2), wherein the torsionally damper section (3) is connected to the coupling section (2) through torsional displacement;
Sealed in a gap (7) formed between the first elastomer member (21) and the torsion damper part (3) and between the pulley (22) side and the torsion damper part (3). Viscous fluid (8),
A torque fluctuation absorbing damper comprising: The gap (7) enclosing the viscous fluid (8)
A partition plate (5) closely fitted to the inner peripheral surface of the pulley (22) and extending radially along the side surface of the torsion damper portion (3);
The torque fluctuation according to claim 1, characterized in that it extends between the inner diameter of the partition (5) and a sealing member (6) slidably interposed between the hub (1). Absorption damper. A sliding bearing (4) is interposed between the inner peripheral surface of the pulley (22) and the outer peripheral surface of the annular mass (32),
The torque fluctuation absorbing damper according to claim 1, characterized in that a gap (7) filled with a viscous fluid (8) communicates with an intervening portion of the sliding bearing (4).

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