JP5611776B2 - Elastic joint - Google Patents

Description

  The present invention relates to an elastic joint that is interposed between a drive shaft and a driven shaft mainly in an automobile or the like, and is used to transmit rotational torque while absorbing vibration, torsion and the like between the two.

  An elastic coupling (flexible coupling) having a vibration damping function is used as a coupling for transmitting rotational torque from a drive shaft to a driven shaft in a power transmission portion such as a drive shaft and a propeller shaft of an automobile.

  As such an elastic joint, a plurality of cylindrical driving side connection elements connected to the driving shaft and a cylindrical driven side connection element connected to the driven shaft are alternately arranged on the same circumference. An endless fiber cord bundle is wound between adjacent drive side connection elements and driven side connection elements, and these connection elements and fiber cord bundles are embedded in a rubber-like elastic material. (For example, see Patent Documents 1 to 4 below).

  Conventionally, as the fiber cord constituting the fiber cord bundle, a double yarn in which two single yarns are usually twisted is used, and both the number of upper twists and the number of lower twists are 30 to 40 times / 10 cm. Something is used.

Japanese Patent No. 4114056 JP 2009-264554 A JP 2010-1926 A JP 2010-25282 A

  With recent increases in output and performance of automobiles, it is required that elastic joints transmit higher rotational torque. In order to transmit a high torque, it is necessary to increase the number of windings of the fiber cord.

  The present invention has been made in view of the above, and an object thereof is to provide an elastic joint capable of improving the vibration isolation performance.

  The present inventor has found that the dynamic spring constant in the high frequency region of the elastic joint can be reduced by increasing the number of twists of the fiber cord used for the elastic joint. The present invention is based on such knowledge.

That is, in the elastic joint according to the present invention, a plurality of drive side connection elements connected to the drive shaft and a plurality of driven side connection elements connected to the driven shaft are alternately arranged on the same circumference. A fiber cord bundle is spanned between each adjacent connection element by winding a fiber cord between the matching drive side connection element and the driven side connection element, and the drive side and driven side connection elements and the fiber cord bundle In the elastic joint formed by embedding in a rubber-like elastic material, as the fiber cord, a plurality of lower twisted yarns obtained by twisting a synthetic fiber filament bundle with a lower twist number of 50 times / 10 cm or more , The present invention is characterized in that a twisted yarn is used which is twisted at an upper twist number of 50 times / 10 cm or more in the direction opposite to the twist direction.

  According to the elastic joint of the present invention, by setting the upper twist number of the twisted yarn used as the fiber cord higher than the conventional one, it is possible to reduce the dynamic spring constant in the high frequency region, and therefore the vibration proof performance. Can be improved. Therefore, for example, when the number of windings of the fiber cord is increased to enable high torque transmission, deterioration of the dynamic spring constant can be suppressed, so that both high torque transmission performance and vibration isolation performance can be achieved. .

It is a front view of the elastic coupling which concerns on embodiment. It is sectional drawing of the II-II line of FIG. It is sectional drawing of the III-III line | wire of FIG. It is sectional drawing of the IV-IV line of FIG. It is a partially expanded view of a fiber cord. It is a graph which shows the dynamic spring characteristic of an Example and a comparative example. It is a graph which shows the fiber cord tensile strength and dynamic spring constant of an Example and a comparative example.

  Next, embodiments of the present invention will be described with reference to the drawings.

  1-4 shows an elastic joint 10 according to the embodiment. The elastic joint 10 is interposed in a connecting member of a driving shaft such as a drive shaft of an automobile and a driven shaft. The driving side connecting element 12 is attached to the driving shaft, while the driven side connecting element 14 is driven. A coupling for transmitting rotational torque from the drive shaft to the driven shaft while absorbing vibration by being attached to the shaft.

  The drive side connection element 12 and the driven side connection element 14 are cylindrical members, and three of these are alternately arranged at equal intervals on the same circumference. Specifically, the connecting elements 12 and 14 are arranged such that the respective axis centers are parallel to each other and are parallel to the center of the circle. The drive side connection element 12 and the driven side connection element 14 have the same structure, and are fastened to the inner periphery of the collar 16 made of metal or resin such as aluminum metal such as aluminum or its alloy. The inner cylinder 18 is made of a metal such as iron that is press-fitted in a fitted state. The inner cylinder 18 is connected to the end of the drive shaft and the end of the driven shaft. A plurality of flanges 16 </ b> A project from the outer peripheral surface of the collar 16 so that fiber cord bundles 20 and 22, which will be described later, can be housed and held at predetermined positions and wound states.

  An endless fiber for reinforcement formed by winding a fiber cord made of a synthetic fiber such as a polyester fiber in a loop in a multilayered manner between adjacent drive side connection elements 12 and driven side connection elements 14 Cord bundles 20 and 22 are wound around.

  Specifically, an endless drive side fiber cord bundle 20 is bridged between each of the three drive side connection elements 12 and the driven side connection element 14 adjacent to the rear side in the rotation direction R at the time of driving. Has been passed. Further, endless driven side fiber cord bundles 22 are bridged between each of the three driving side connection members 12 and the driven side connection member 14 adjacent to the front side in the rotational direction R at the time of driving. ing.

  Here, the rotation direction R is the rotation direction of the elastic joint 10 at the start of driving due to vehicle start or the like or during normal driving rotation. In the elastic joint 10, at the time of such driving, a large tensile force acts between each driving side connecting element 12 and the driven side connecting element 14 on the rear side in the rotation direction R, so that the driving side fibers stretched between them. The number of cords of the cord bundle 20, that is, the cross-sectional area of the cord bundle, is set to be larger than the number of cords of the other driven side fiber cord bundle 22, that is, the cross-sectional area of the cord bundle.

  In the present embodiment, the drive side fiber cord bundle 20 is arranged in the axial center of each connection element 12, 14 and the driven side fiber cord bundle 22 is connected to each connection element 12, by the flange 16 A provided on the outer peripheral surface of the collar 16. 14 are respectively wound around the outer peripheral surface of the collar 16 in a divided manner at both ends in the axial direction.

  The drive side connection elements 12, the driven side connection elements 14, the drive side fiber cord bundles 20, and the driven side fiber cord bundles 22 are at least inner holes of the connection elements 12, 14, that is, inside the inner cylinder 18. The rubber-like elastic material 24 is embedded in the rubber-like elastic material 24 by molding (here, rubber vulcanization molding) so that the hole is exposed to the outside.

  That is, the rubber-like elastic material 24 is set after the connection elements 12 and 14 are set in a predetermined mold and the fiber cord bundles 20 and 22 are wound around the connection elements 12 and 14, or The fiber cord bundles 20 and 22 are wound around the connecting elements 12 and 14 and set in a predetermined mold, and then a rubber material is injected into the mold and vulcanized to integrally vulcanize and mold. The

  The elastic joint 10 has a substantially rectangular cross section as shown in FIG. 4 and a substantially polygonal shape (here, approximately six in the axial direction of the elastic joint) when viewed from the front as shown in FIG. It is integrally formed so as to form a (round) ring. Specifically, the elastic joint 10 includes a hexagonal outer peripheral surface 26 having the embedded portions of the connection elements 12 and 14 as apexes, and a hexagonal inner peripheral surface 28 having the embedded portions of the connection elements 12 and 14 as apexes. Thus, a substantially hexagonal ring is formed. In this example, more specifically, the outer peripheral surface 26 is formed with rounded corners corresponding to the apexes of the hexagon.

  In the middle part of the rubber-like elastic material 24 between the adjacent connection elements 12 and 14, the durability is improved by increasing the free length of the surface against the elastic deformation of the rubber-like elastic material 24 and improving the cooling effect. In order to achieve this, a hole 30 that sinks in the axial direction (thickness direction) of the elastic joint is formed with the thin film 32 remaining on one end side in the axial direction as shown in FIGS.

  In the elastic joint 10 of the present embodiment, as the fiber cords 34 constituting the fiber cord bundles 20, 22, two twisted yarns 36, 36 formed by twisting a synthetic fiber filament bundle are 45 times / 10 cm or more. A twisted yarn twisted by the number of upper twists is used (see FIG. 5). The twisted yarn is a double yarn formed by drawing two lower twisted yarns 36, 36 that are twisted in the same direction and twisting them together by twisting in the direction opposite to the twisted direction of the lower twisted yarn 36. Specifically, the lower twisted yarn 36 is obtained by left-twisting (Z-twisting) a bundle of synthetic fiber filaments, and the fiber cord 34 is formed by right-twisting (S twisting) two lower twisted yarns 36 and 36. . In this way, twisting and the like of the fiber cord 34 can be prevented by reversing the lower twist and the upper twist. The number of the lower twisted yarns constituting the fiber cord 34 is preferably two as shown in the drawing from the viewpoint of cost and performance, but may be three or more.

  In the fiber cord 34, it is important to set the number of upper twists to 45 times / 10 cm or more as described above. Generally, in filament yarns, the tensile strength decreases as the number of twists increases. Therefore, it is considered that the number of twists is set to be large in the conventional fiber cords used for elastic joints that require high torque transmission performance. It was not done. The inventor has increased the number of upper twists to 45 times / 10 cm or more with respect to such technical common sense, thereby reducing the tensile strength of the fiber cord more than the amount of reduction in the twist direction (rotation direction R) of the elastic joint. It was found that the dynamic spring constant can be reduced. The reason why the dynamic spring constant can be reduced in this way is considered to be that hysteresis loss due to the movement of the fiber by the increase in the number of twists when the fiber cord is pulled increases. The number of upper twists is more preferably 48 times / 10 cm or more from the viewpoint of the effect of reducing the dynamic spring constant. Regarding the upper limit of the number of upper twists, considering the function of the fiber cord 34, it is desirable that the tensile strength is high with respect to the load in the tensile direction (rotational torque at the elastic joint 10) and that the upper cord is appropriately stretched. Elongation increases by increasing the number of twists, but if it is twisted too much, it will no longer extend and the tensile strength will decrease. Moreover, when it twists too much, it will become the tendency for the reduction effect of a dynamic spring constant to blunt. Therefore, from these balances, the number of upper twists is preferably 55 times / 10 cm or less, more preferably 52 times / 10 cm or less.

  The number of twists of the fiber cord 34 (that is, the number of twists of the twisted yarn 36) is also preferably 45 times / 10 cm or more. By setting the number of twists high in this way, the effect of reducing the dynamic spring constant can be obtained. Can be improved. The lower limit of the number of lower twists is more preferably 48 times / 10 cm or more. The upper limit of the number of lower twists is preferably 55 times / 10 cm or less, more preferably 52 times / 10 cm or less. The number of lower twists and the number of upper twists are preferably set to be the same in order to reduce the occurrence of snar, that is, the difference between the number of upper twists and the number of lower twists is preferably set to 2 times / 10 cm or less.

  Examples of the synthetic fiber filaments constituting the fiber cord 34 include polyester fiber, nylon fiber, aramid fiber, carbon fiber, rayon fiber, acrylic fiber, and polyvinyl chloride fiber. Among these, it is particularly preferable to use a polyester fiber.

  The fineness of the lower twisted yarn 36 constituting the fiber cord 34 is preferably 1000 to 2000 tex (tex) in order to exhibit high torque transmission performance in the elastic joint. Further, the fineness of the twisted yarn (fiber cord 34) formed by twisting them is preferably 2000 to 4200 tex. Further, the outer diameter (thickness) of the fiber cord 34 is preferably 0.4 to 1.0 mm.

  The fiber cord 34 preferably has a twist angle θ of 30 ° to 60 ° with respect to the yarn axis S on the surface of the twisted yarn. Here, the twist angle θ is an average value of twist angles measured at arbitrary 10 locations. By setting such a twist angle θ, it is possible to improve the effect of reducing the dynamic spring constant in the elastic joint while suppressing a decrease in tensile strength. That is, if the twist angle θ is less than 30 °, the effect of reducing the dynamic spring constant may be insufficient. Conversely, if the twist angle θ exceeds 60 °, the decrease in tensile strength may be too great. The twist angle θ is more preferably 45 ° to 55 °. The twist angle θ is set based on the thickness (fineness) and the number of twists of the lower twisted yarn 36 to be twisted. If the same fineness, the twist angle θ increases as the number of twists increases, and if the same twist number, the fineness increases. As the twist angle θ increases, the twist angle θ increases.

  The number of turns of the fiber cord 34 wound between the adjacent drive side connection element 12 and the driven side connection element 14 is not particularly limited, but is 180 to 200 in the drive side fiber cord bundle 20. The driven fiber cord bundle 22 is preferably 120 to 140 times. Since the dynamic spring constant of the elastic joint can be reduced by increasing the number of twists of the fiber cord 34 as described above, even if the number of windings is increased compared to the prior art in order to enable high torque transmission It is possible to prevent the performance from deteriorating. Therefore, it is possible to achieve both durability against high rotational torque and vibration-proof performance.

About the elastic joint 10 of the said embodiment, the number of upper twists and the number of lower twists of the fiber cord 34 were changed as shown in following Table 1, and the elastic joint of an Example and a comparative example was made as an experiment. However, Example 1 below is a reference example. The fiber cord 34 is obtained by first twisting a filament bundle made of polyester fiber filaments with the number of lower twists shown in Table 1, aligning two obtained lower twisted yarns, and lower twisting with the number of upper twists shown in Table 1. (The outer diameter (thickness) of the fiber cord is about 0.7 mm). About the obtained fiber cord, while measuring twist angle | corner (theta), tensile strength and breaking elongation were measured. Moreover, the elastic coupling 10 shown in FIGS. 1-4 was produced by the winding number shown in Table 1 using this fiber cord. About the obtained elastic coupling, the dynamic spring constant was measured. Each measuring method is as follows.

-Tensile strength, elongation at break: Measured by setting a fiber cord in a tensile tester and pulling the fiber cord at a distance between gauge points of 20 mm and a tensile speed of 30 ± 2 cm / min.

-Dynamic spring constant: A constant acceleration of 5G was applied to the elastic joint in the torsion direction, and the dynamic spring constant was measured in a frequency band of 15 to 500 Hz.

  The results are as shown in Table 1 and FIGS. Compared to Comparative Example 1 in which the number of upper twists and the number of lower twists are both 40 times / 10 cm, the dynamic spring constant in the high frequency region of 100 Hz is reduced in Examples 1 to 3 in which the number of twists is increased. Anti-vibration performance was improved. In particular, in Example 2 in which the number of upper twists and the number of lower twists were both 50 times / 10 cm, compared to Comparative Example 1, the dynamic spring while suppressing a decrease in tensile strength per fiber cord to about 5%. The constant was reduced by 10%.

  As shown in FIG. 6, when the dynamic spring constant of 100 to 500 Hz was compared between Example 2 and Comparative Example 1, the dynamic spring constant was reduced by about 10% over almost the entire region. On the other hand, although the tensile strength per fiber cord was reduced by about 5% as described above, durability was evaluated by repeatedly applying high torque (± 1500 Nm) in the rotational direction R to the elastic joint at 2 Hz. However, the durability as an elastic joint is at the same level as that of Comparative Example 1, and thus the vibration-proofing effect is enhanced without impairing the durability.

  In the above-described embodiment, the elastic joint 10 is configured by a total of six connection elements including the three drive side connection elements 12 and the three driven side connection elements 14, but the number of connection elements is limited to this. For example, a total of eight connection elements including four drive side connection elements and four driven side connection elements may be used. By increasing the number of connecting elements from six to eight, the durability against high rotational torque can be improved without increasing the outer diameter, so both high torque transmission performance and vibration isolation performance can be achieved at a higher level. be able to.

  The present invention can be particularly suitably used as a coupling having a vibration damping function for transmitting rotational torque from a drive shaft to a driven shaft in a power transmission portion such as a drive shaft and a propeller shaft of an automobile.

DESCRIPTION OF SYMBOLS 10 ... Elastic coupling 12 ... Drive side connection element 14 ... Drive side connection element 20 ... Drive side fiber cord bundle 22 ... Drive side fiber cord bundle 24 ... Rubber-like elastic material 34 ... Fiber cord 36 ... Lower twist yarn R ... Rotation direction S ... Yarn axis θ ... Twisting angle

Claims (2)

A plurality of drive side connection elements connected to the drive shaft and a plurality of driven side connection elements connected to the driven shaft are alternately arranged on the same circumference, and adjacent drive side connection elements and driven side connection elements A fiber cord bundle is spanned between adjacent connection elements by winding a fiber cord between them, and the drive side and driven side connection elements and the fiber cord bundle are embedded in a rubber-like elastic material. In elastic joints,
As the fiber cord, a plurality of lower twisted yarns obtained by twisting a synthetic fiber filament bundle with a lower twist number of 50 times / 10 cm or more are twisted 50 times / 10 cm or more in a direction opposite to the twist direction of the lower twisted yarn. An elastic joint characterized by using twisted yarns twisted together in numbers. Elastic joint according to claim 1, wherein the angle twist relative to the yarn axis in the surface of the twisting is 30 ° to 60 °.