JP6438309B2 - Torsional damper - Google Patents

Description

  The present invention relates to a torsional damper attached to a rotating shaft such as a crankshaft of an automobile engine, for example.

  The pulley attached to the end of the crankshaft of an automobile engine has a torsional vibration reduction function to prevent the occurrence of problems due to torsional vibration (vibration in the rotational direction) that occurs on the crankshaft as the engine is driven. That is, a torsional damper is configured. This type of torsional damper is equipped with a dynamic vibration absorber consisting of a rubber elastic body and a mass body. The resonance frequency of this dynamic vibration absorber is tuned to a vibration frequency region where the torsional amplitude of the crankshaft is maximized. The vibration displacement due to the resonance of the part is generated in the opposite direction to the input vibration, thereby exhibiting a vibration damping effect that reduces the peak of the torsional amplitude of the crankshaft.

  In particular, when the amplitude of the torsional vibration of the crankshaft is large, use a double mass damper with two sets of dynamic vibration absorbers with different resonance frequencies instead of a single mass damper with one set of dynamic vibration absorbers. The torsional vibration is reduced.

  FIG. 4 shows an example of a conventional double-mass type torsional damper, that is, a hub 300 attached to the shaft end of a crankshaft (not shown) in an inner peripheral boss portion 301 and a concentric outer peripheral side of the hub 300. The first dynamic vibration absorber having a structure in which the annular mass body 101 arranged on the elastic member is elastically connected via a first elastic body 102 made of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity). The second mass body 201 concentrically arranged along with the first dynamic vibration absorbing portion 100 on the outer peripheral side of the portion 100 and the hub 300 via the second elastic body 202 made of a rubber-like elastic material A second dynamic vibration absorber 200 having an elastically connected structure is provided.

  As shown in FIG. 5, the conventional double mass type torsional damper has a crankshaft of a crankshaft driven by a first dynamic vibration absorber 100 whose torsion direction resonance frequency is tuned to a frequency f1 of a peak p1 of the crankshaft torsion amplitude. The torsional amplitude peak p1 is divided into two amplitude peaks p2 and p3 having smaller amplitudes, and the second dynamic vibration absorber tuned to the frequency f2 of the amplitude peak p2 out of the divided amplitude peaks p2 and p3. By 200, the amplitude peak p2 is further divided into two amplitude peaks p4 and p5 having smaller amplitudes. As this type of double-mass type torsional damper, for example, one disclosed in Patent Document 1 is disclosed.

Japanese Utility Model Publication No. 60-1

  However, according to the conventional double mass type torsional damper, the second dynamic vibration absorber 200 can reduce only one of the amplitude peaks p2 and p3 divided by the first dynamic vibration absorber 100. is there.

  Further, in order to reduce the other amplitude peak (p3 in the illustrated example), it is conceivable to further provide a third dynamic vibration absorber to form a triple mass type. In this case, the weight of the torsional damper is considered. Not only becomes heavy as a whole, but also increases the installation space.

  The present invention has been made in view of the above points, and the technical problem is that it is possible to obtain the same vibration reduction effect as that of the triple mass type without increasing the weight and the installation space. To provide a torsional damper.

  As a means for effectively solving the technical problem described above, a torsional damper according to the invention of claim 1 is arranged concentrically on a hub attached to a shaft end of a crankshaft and on an outer peripheral side of the hub. A first dynamic vibration absorber having a structure in which an annular mass body is connected to be displaceable in a circumferential direction via a first elastic body made of a rubber-like elastic material; and a circumferential direction disposed on the outer peripheral side of the hub A plurality of piece-like mass bodies are connected to the hub via a second elastic body made of a rubber-like elastic material so as to be displaceable in the radial direction and the circumferential direction, and the torsional direction resonance frequency is the first dynamic frequency. A second dynamic vibration absorber tuned to a frequency lower than the resonance frequency in the torsional direction of the dynamic vibration absorber, and provided on the outer periphery of the fragmented mass body so as to face the inner peripheral surface of the annular mass body in the radial direction. The inner circumferential surface of the annular mass body by centrifugal force A frictional engagement portion capable of frictional engagement, and a torsional direction resonance frequency when the first dynamic vibration absorption portion and the second dynamic vibration absorption portion are connected in parallel with each other via the friction engagement portion. The first dynamic vibration absorber is tuned to a higher frequency side than the torsional direction resonance frequency.

  In the above configuration, in the low-speed rotation range where the rotation speed is less than a predetermined value, the friction engagement portion provided on the outer periphery of the fragmented mass body is in a non-contact state with the inner peripheral surface of the annular mass body. The vibration absorber and the second dynamic vibration absorber have a torsional direction resonance frequency independent from each other, and the first dynamic vibration absorber reduces the torsional vibration of the crankshaft in a predetermined frequency range, and the second dynamic vibration absorber Can reduce the torsional vibration of the crankshaft on the lower frequency side. Further, in a high-speed rotation range where the rotation speed is a predetermined value or more, the friction engagement portion provided on the outer periphery of the fragmented mass body is frictionally engaged with the inner peripheral surface of the annular mass body by centrifugal force. The dynamic vibration absorbing portion and the second dynamic vibration absorbing portion are connected to each other in parallel via the friction engagement portion, and the crankshaft is located on the higher frequency side than the torsional direction resonance frequency of the first dynamic vibration absorbing portion. Torsional vibration can be reduced.

  A torsional damper according to a second aspect of the present invention is the configuration described in the first aspect, wherein the torsional direction resonance frequency of the first dynamic vibration absorber is tuned to a frequency region in which the amplitude peak in the torsional direction of the crankshaft is obtained. And the torsional direction resonance frequency of the second dynamic vibration absorber is tuned to a frequency region of an amplitude peak on the low frequency side among the amplitude peaks divided into two by the first dynamic vibration absorber, The torsional direction resonance frequency when the dynamic vibration absorbing portion and the second dynamic vibration absorbing portion are coupled to each other via the friction engagement portion is divided into two amplitude peaks by the first dynamic vibration absorbing portion. Among them, it is tuned to the frequency region of the amplitude peak on the high frequency side.

  According to the above configuration, the torsional amplitude peak of the crankshaft is reduced by the first dynamic vibration absorber, and the amplitude peak on the low frequency side among the divided amplitude peaks is reduced by the second dynamic vibration absorber. The amplitude peak on the high frequency side is caused by the first dynamic vibration absorber and the second dynamic vibration absorber connected in parallel with each other by frictionally engaging the friction engagement portion with the inner peripheral surface of the annular mass body. Reduced.

  A torsional damper according to a third aspect of the present invention is the structure described in the first or second aspect, wherein the frictional engagement portion is formed of a rubber-like elastic material integrally joined to the outer periphery of the fragmentary mass body. Is.

  According to the above configuration, in addition to the large frictional engagement force of the frictional engagement portion made of a rubber-like elastic material, the centrifugal mass acting on the annular mass body causes a gap between the annular mass body and the inner peripheral surface of the annular mass body. Since the frictional engagement portion is compressed and the spring constant increases, the first dynamic vibration absorption portion and the second dynamic vibration absorption portion are securely connected via the friction engagement portion, and the friction engagement portion Can be prevented from being hit by the contact between the annular mass body and the inner peripheral surface of the annular mass body, and can be prevented from being hit by the first dynamic vibration absorbing portion and the second dynamic vibration absorbing portion.

  According to the torsional damper according to the present invention, the first dynamic vibration absorbing portion and the second dynamic vibration absorbing portion can be connected in parallel with each other via the friction engagement portion by centrifugal force, so that weight and mounting The vibration reduction effect in a wide frequency range similar to that of the triple mass type torsional damper can be obtained without increasing the space.

It is the figure which looked at preferable embodiment of the torsional damper which concerns on this invention from the extension direction of the axial center O. FIG. It is sectional drawing cut | disconnected and shown by the II-O-II 'line | wire in FIG. It is a diagram which shows the characteristic of the torsional damper which concerns on this invention. FIG. 6 is a half cross-sectional view showing an example of a conventional double mass type torsional damper cut along a plane passing through an axis O; It is a diagram which shows the characteristic of the conventional double mass type torsional damper.

  A preferred embodiment of a torsional damper according to the present invention will be described below with reference to FIGS.

  The torsional damper shown in FIGS. 1 and 2 includes a hub 4 attached to a shaft end of a crankshaft (not shown), a first dynamic vibration absorber 1 and a first dynamic vibration absorber 1 arranged concentrically on the outer peripheral side of the hub 4. The second dynamic vibration absorbing portion 2 and the friction engagement portion 3 capable of connecting the first dynamic vibration absorbing portion 1 and the second dynamic vibration absorbing portion 2 in parallel with each other by centrifugal force.

  Specifically, the hub 4 includes a first hub member 41 and a second hub member 42 manufactured by casting a metal material or the like, and the first hub member 41 and the second hub member 42 are integrally coupled to each other. is there. Of these, the first hub member 41 has a boss portion 41a that is a fixed portion to the shaft end of the crankshaft on the inner periphery, an intermediate portion 41b that extends from the boss portion 41a to the outer diameter side, and an outer portion of the intermediate portion 41b. The second hub member 42 includes a disc portion 42a having a radially inner end integrated with the outer peripheral surface of one end of the boss portion 41a of the first hub member 41 by fitting or the like. The rim portion 42b extends in a cylindrical shape from the outer diameter end of the disk portion 42a.

  The first dynamic vibration absorbing portion 1 includes a metal sleeve 11 that is press-fitted to the outer peripheral surface of the rim portion 41 c of the first hub member 41 in the hub 4, and an annular mass body 12 that is concentrically disposed on the outer peripheral side thereof. And a first elastic body 13 which is integrally vulcanized (vulcanized and bonded) between the annular mass body 12 and the sleeve 11 with a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity). It consists of. That is, the first dynamic vibration absorbing portion 1 press-fits the sleeve 11 to the outer peripheral surface of the rim portion 41 c of the first hub member 41, thereby changing the annular mass body 12 into the first elastic body 13 and the sleeve 11. It has the structure connected with the hub 4 via the hub so that a circumferential displacement was possible.

  The annular mass body 12 in the first dynamic vibration absorbing portion 1 is manufactured by casting a metal material or the like, and the outer peripheral side of the rim portion 41 c of the first hub member 41 and the second hub member 42 in the hub 4. It has an axial length that surrounds both the outer peripheral sides of the rim portion 42b. Further, a poly V groove 12a is formed on the outer peripheral surface of the annular mass body 12, and an endless belt (not shown) is wound around it.

  Here, in the characteristic diagram shown in FIG. 3, a is a characteristic line indicating the torsional vibration characteristics of the crankshaft when no torsional damper is attached, and b is a single mass type torsional damper, that is, the first dynamic damper. 3 is a characteristic line showing the vibration characteristics when the torsional damper having only the dynamic vibration absorber 1 is attached, and c is a characteristic line showing the vibration characteristics when the torsional damper of the illustrated embodiment is attached. The torsional direction resonance frequency of the first dynamic vibration absorber 1 is determined by the torsional direction resonance frequency of the crankshaft by the circumferential shear spring constant of the first elastic body 13 and the circumferential inertial mass of the annular mass body 12. In other words, it is tuned to a frequency f1 that becomes an amplitude peak p1 in the vibration characteristic a shown in FIG.

  The second dynamic vibration absorbing portion 2 is located on the outer peripheral side of the rim portion 42b of the second hub member 42 in the hub 4 and near one end of the annular mass body 12 in the first dynamic vibration absorbing portion 1 (closer to the left end in FIG. 2). A plurality of pieces (4 in the example shown in FIG. 1) in the form of circular arcs of the same shape and the same size, which are arranged on the inner peripheral side and are formed by cutting the metal ring at equal intervals in the circumferential direction, Each piece-like mass body 21 and the second elastic body 22 integrally vulcanized (vulcanized and bonded) with a rubber-like elastic material between the outer peripheral surfaces of the rim portions 42b of the second hub member 42 are configured. Is done. That is, the second dynamic vibration absorber 2 has a structure in which each piece-like mass body 21 is connected to the hub 4 via the second elastic body 22 so as to be displaceable in the circumferential direction and the radial direction.

  The second elastic body 22 has a shape separated in the circumferential direction through the slit 2a at a position between the fragmentary mass bodies 21 and 21 adjacent to each other in the circumferential direction. For this reason, each piece-like mass body 21 can be displaced in the radial direction against the tensile elasticity of the second elastic body 22 by a centrifugal force acting during rotation.

  The torsional direction resonance frequency of the second dynamic vibration absorber 2 is determined by the first dynamic vibration absorber 1 by the circumferential shear spring constant of the second elastic body 22 and the circumferential inertia mass of the fragmented mass body 21. Is tuned to a frequency range lower than the torsional direction resonance frequency f1, and, as shown in detail in FIG. 3, the first dynamic vibration absorber 1 divides the crankshaft torsional amplitude peak p1 into a small amplitude peak p2. , P3 are tuned to the frequency f2 of the amplitude peak p2 on the low frequency side.

  The rubber-like elastic material forming the second elastic body 22 is molded so as to surround each piece-like mass body 21. That is, both end surfaces in the axial direction of each piece-like mass body 21 are covered with the elastic layer 22 a extending from the second elastic body 22, and the friction engagement portion 3 is formed by the elastic layer covering the outer peripheral surface of each piece-like mass body 21. Is formed. When the torsional damper is not rotated, the outer peripheral surface of the friction engagement portion 3 is close to and opposed to the inner peripheral surface 12b near the one end of the annular mass body 12 in the first dynamic vibration absorber 1 through a slight gap. When the rotational speed is equal to or higher than a predetermined rotational speed, the frictional engagement is brought into close contact with the inner peripheral surface 12b near one end of the annular mass body 12 in accordance with the radial displacement of the fragment mass body 21 due to centrifugal force. is there.

  And in the state which the outer peripheral surface of the friction engaging part 3 frictionally engaged with the inner peripheral surface 12b near the one end of the annular mass body 12, the fragmentary mass body 21 on which the centrifugal force acts acts between the annular mass body 12. The first dynamic vibration absorbing portion 1 and the second dynamic vibration absorbing portion 2 are connected in parallel to each other in the torque transmission direction via the friction engagement portion 3 that receives the compressive force. The engaging portion 3 also functions as an elastic body having a high spring constant by being pressed and compressed by the fragmentary mass body 21 that is about to be displaced in the outer diameter direction. Therefore, the torsional direction resonance frequency of the first dynamic vibration absorption unit 1 and the second dynamic vibration absorption unit 2 connected via the friction engagement unit 3 is the torsional direction resonance frequency of the first dynamic vibration absorption unit 1. As shown in FIG. 3, the first dynamic vibration absorber 1 preferably has a higher frequency out of the smaller amplitude peaks p2 and p3 divided by the first dynamic vibration absorber 1, as shown in FIG. It is tuned to the frequency f3 of the side amplitude peak p3.

  The torsional damper having the above-described configuration is fixed to the shaft end of the engine crankshaft by a bolt and a key (not shown) in the shaft hole of the boss portion 41a of the first hub member 41 in the hub 4, and rotates together with the crankshaft. It is what is done.

  When the frequency of the torsional vibration input through the hub 4 with the rotation of the crankshaft is in the vicinity of the frequency f1 that becomes the peak p1 of the torsional amplitude of the crankshaft, the torsional vibration with such a frequency is generated. In the generated rotation speed range, the frictional engagement portion 3 provided on the outer periphery of the fragmented mass body 21 in the second dynamic vibration absorption portion 2 has an annular mass body in the first dynamic vibration absorption portion 1 through a slight gap. 12 is not in contact with the inner peripheral surface 12b. For this reason, the first dynamic vibration absorber 1 whose torsion direction resonance frequency is tuned to the frequency f1 of the torsional amplitude peak p1 of the crankshaft resonates independently of the second dynamic vibration absorber 2, and the resonance The dynamic vibration absorbing action in which the torque is generated in the direction opposite to the torque of the input vibration reduces the crankshaft torsional amplitude peak p1 and divides it into two amplitude peaks p2 and p3 having smaller amplitudes.

  The torsional vibration frequency input via the hub 4 has an amplitude on the lower frequency side than the torsional amplitude peak p1 of the crankshaft among the amplitude peaks p2 and p3 divided by the first dynamic vibration absorber 1. When the frequency is near the frequency f2 at which the peak p2 is reached, the rotational speed corresponding to such a frequency is further on the low speed side than the rotational speed at which the torsional vibration at the peak p1 is generated. It is in a non-contact state with the inner peripheral surface 12 b of the annular mass body 12. Accordingly, the second dynamic vibration absorbing portion 2 whose torsional direction resonance frequency is tuned to the frequency f2 having the amplitude peak p2 resonates, and the fragment mass bodies 21 have the same shape and the same mass, so that they are continuous with each other. The amplitude peak p2 is reduced by the dynamic vibration absorption action in which the vibration is displaced in a translational manner and the torque due to the resonance is generated in the opposite direction to the torque of the input vibration, and two amplitudes with smaller amplitudes are further reduced. Divided into peaks p4 and p5.

  Further, the frequency of torsional vibration input via the hub 4 is higher in amplitude than the peak p1 of the crankshaft torsional amplitude among the amplitude peaks p2 and p3 divided by the first dynamic vibration absorber 1. In the vicinity of the frequency f3 at which the peak p3 is obtained, in the high-speed rotation region corresponding to the frequency f3, the frictional force is increased due to an increase in the centrifugal force acting on the fragmentary mass body 21 of the second dynamic vibration absorber 2. The outer peripheral surface of the joint portion 3 is frictionally engaged with the inner peripheral surface 12b near one end of the annular mass body 12, that is, the first dynamic vibration absorbing portion 1 and the second dynamic vibration portion 3 are interposed via the friction engaging portion 3. The vibration absorbers 2 are connected in parallel to each other in the torque transmission direction. Then, the first dynamic vibration absorber 1 and the second dynamic vibration absorber 2 connected in this way resonate near the frequency f3, and the dynamic vibration generated by the resonance in the direction opposite to the torque of the input vibration. By the action, the amplitude peak p3 is reduced and further divided into two amplitude peaks p6 and p7 having smaller amplitudes.

  That is, according to the illustrated embodiment, the peak p1 of the torsional amplitude of the crankshaft is reduced by the first dynamic vibration absorber 1, and the amplitude peak on the low frequency side among the amplitude peaks p2 and p3 divided thereby. p2 is reduced by the second dynamic vibration absorber 2, and the amplitude peak p3 on the high frequency side is parallel to each other as the friction engagement portion 3 is frictionally engaged with the inner peripheral surface 12b of the annular mass body 12 by centrifugal force. It is reduced by the connected first dynamic vibration absorber 1 and second dynamic vibration absorber 2. Therefore, only the first dynamic vibration absorbing portion 1 and the second dynamic vibration absorbing portion 2 are provided without increasing the weight and mounting space as in the case of the triple mass type by providing the third dynamic vibration absorbing portion. The vibration can be reduced in the same wide frequency range (rotational speed range) as the triple mass type torsional damper.

  In addition, since both end surfaces in the axial direction of each piece-like mass body 21 in the second dynamic vibration absorber 2 are covered with the elastic layer 22a extending from the second elastic body 22, the first dynamic vibration absorber 1 and Even when the second dynamic vibration absorbing portion 2 resonates in the axial direction in different rotational speed ranges, the piece-like mass body 21, the rim portion 41c of the first hub member 41, and the sleeve 11 may be in metal contact. Therefore, damage due to metal contact can be prevented and the hitting sound can be reduced.

DESCRIPTION OF SYMBOLS 1 1st dynamic vibration absorption part 12 Annular mass 13 First elastic body 2 Second dynamic vibration absorption part 2a Slit 21 Fragment-like mass body 22 Second elastic body 22a Elastic layer 3 Friction engagement part 4 Hub

Claims (3)

  A hub attached to the shaft end of the crankshaft and an annular mass disposed concentrically on the outer peripheral side of the hub are connected via a first elastic body made of rubber-like elastic material so as to be displaceable in the circumferential direction. A first dynamic vibration absorber having a structure and a plurality of circumferential mass pieces arranged on the outer peripheral side of the hub are radially arranged on the hub via a second elastic body made of a rubber-like elastic material. And a second dynamic vibration absorber connected in a circumferentially displaceable manner, wherein the torsional direction resonance frequency is tuned to a lower frequency side than the torsional direction resonance frequency of the first dynamic vibration absorber, and the fragment A friction engagement portion provided on an outer periphery of the annular mass body and radially opposed to an inner circumferential surface of the annular mass body and capable of frictional engagement with an inner circumferential surface of the annular mass body by centrifugal force; The dynamic vibration absorption part and the second dynamic vibration absorption part are interposed through the friction engagement part. Torsional direction resonance frequency when connected in parallel to each other, torsional damper, characterized in that it is tuned from a high frequency side torsional direction resonance frequency of said first dynamic vibration absorbing portion.   The torsional direction resonance frequency of the first dynamic vibration absorber is tuned to a frequency region where the amplitude peak in the torsional direction of the crankshaft is obtained, and the torsional direction resonance frequency of the second dynamic vibration absorber is It is tuned to the frequency range of the amplitude peak on the low frequency side among the amplitude peaks divided into two by the vibration absorbing portion, and the first dynamic vibration absorbing portion and the second dynamic vibration absorbing portion are mutually connected via the friction engagement portion. 2. The torsional direction resonance frequency when coupled is tuned to a frequency region of an amplitude peak on a high frequency side among amplitude peaks divided into two by the first dynamic vibration absorber. The torsional damper described in 1.   The torsional damper according to claim 1 or 2, wherein the friction engagement portion is formed of a rubber-like elastic material integrally joined to the outer periphery of the fragment-like mass body.

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