JPH06147268A - Torque cam damper - Google Patents

Abstract

PURPOSE:To absorb twist vibration of high torque by providing cam means and a resilient member to exert energization thereon and varying the bassetite load of the resilient member through axial movement of a ball support member by means of the centrifugal force of a ball according to the number of revolutions. CONSTITUTION:When high torque is exerted on an input flange 2 and a fluctuation in a rotation force high enough to be against the energization force of a resilient member 14 is produced, a drive cam 4 is momentarily displaced in a rotation direction and axially slid so that a gap between a cam 4 and driven cams 10 and 11 is increased. Since, in this case, the cam 11 is under contact with a fixing member 26a, it is not slid in an axial direction but the cams 4 and 10 are slid in a direction in which the resilient member 14 is compressed. Thus, a fluctuation in a rotation force is absorbed by means of the resilient member 14 and rapid twist vibration doe not occur. The bassettite load of the resilient member 14 is raised by a twist characteristic varying means 22 according to the increase of rotation. A buffering mechanism operated even through a low rotation torque fluctuation when the number of revolutions of low is operated to suppress actuation of buffering operation in a high number of revolutions region when a rotation torque fluctuation is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for damping torsional vibration of a propeller shaft, and more particularly to a torque cam which converts rotational fluctuation of torsional vibration into axial fluctuation by using a cam and absorbs vibration due to rotational fluctuation. Regarding dampers.

[0002]

2. Description of the Related Art Conventionally, a dynamic damper using rubber as a damper of a propeller shaft is known, but the effect of absorbing vibration is obtained only at a certain frequency. In addition, a viscous damper using a viscous fluid has a large outer diameter due to its structure and is always slippery, resulting in poor efficiency and being unable to be mounted on the propeller shaft portion.

The torque fluctuation damping device disclosed in Japanese Patent Laid-Open No. 61-171935 converts the fluctuation of the rotational torque into a fluctuation of the cam member in the axial direction through a cam mechanism, thereby rotating the torque to the outer cylinder. Although it is intended to buffer the transmission of fluctuations, this is for a two-wheeled vehicle, and it was difficult to cope with high torque rotation fluctuations. That is, in order to cope with the high torque rotation fluctuation of a four-wheel vehicle, the outer diameter dimension must be increased, and there is no rotation torque fluctuation absorbing device that can be mounted on the current propeller shaft of a four-wheel vehicle.

[0004]

Therefore, as a countermeasure against torsional vibration, the present invention can absorb the torsional vibration of high torque without increasing the outer diameter of the device and can cope with a wide range of frequencies. An object of the present invention is to provide a torque cam damper which has a damping effect of torsional vibration and has a variable torsional characteristic corresponding to the number of rotations.

[0005]

In order to solve the above-mentioned problems, the present invention transmits the rotational torque fluctuation to the outer cylinder by converting the fluctuation of the rotational torque applied to the center shaft into the axial fluctuation by the cam means. In the torque cam damper for buffering the torque, cam means axially engaged and arranged via a rotating body and elastic members for urging toward the cam means are provided, and the cams are provided on both sides in the axial direction of the elastic member. Means for engagingly arranging, a ball, a ball support member having a cam surface that abuts at least one surface of the ball and movably arranged in the axial direction, and a ball holding member for movably holding the ball in the radial direction. A twist characteristic varying means comprising a member,
A torque cam, characterized in that a torsion characteristic varying means for varying the spring set load of the elastic member according to the rotational speed through axial movement of the ball supporting member in accordance with the centrifugal force applied to the ball is provided. Provide a damper.

Further, the cam means comprises a driving cam, a rotating body and a driven cam, and the driven cam via the rotating body engages with both sides of the driving cam in the axial direction. A torque cam damper characterized by being arranged.

The drive cam rotates integrally with the center shaft so as to be rotatable relative to the outer cylinder within a predetermined angle, and a stopper is provided to prevent relative rotation between the drive cam and the outer cylinder. Provided is a torque cam damper characterized by having a play angle of the predetermined angle between the drive cam and the outer cylinder.

Further, there is provided a torque cam damper in which a plurality of the twist characteristic varying means are provided in series in the axial direction.

[0009]

In the torque cam damper of the present invention, since the cam means are provided on both sides of the elastic member and the amount of contraction of the length of the elastic member can be increased, the torsion of high torque can be achieved without increasing the outer diameter of the device. In addition to a vibration absorbing action against the vibration, a centrifugal force acts radially on the balls of the torsion characteristic varying means during rotation to move the ball support member in the axial direction, thereby pressing the elastic member. By increasing the spring set load in response to an increase in the number of revolutions and making the torsional characteristics variable, the buffering operation of the torque cam damper is restrained against a low rotational torque fluctuation in the high revolution region.

Further, in the cam means according to the second aspect of the present invention, a rotating body and a driven cam are provided on both sides of the driving cam, and since there are two rotating bodies, a simple driving cam,
It is possible to cope with high-torque torsional vibration as compared with a cam means including a rotating body and a driven cam.

According to the third aspect of the invention, since the drive cam can rotate in the circumferential direction only within the range of the play angle, it is not necessary to provide a dedicated stopper means.

Further, by providing a plurality of the twisting characteristic varying means in the axial direction, the increase (offset) of the spring set load corresponding to the rotational speed can be further increased while the radial dimension remains the same. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment of a torque cam damper of the present invention.
5 to 5 and will be described in detail. As the rotating body of the torque transmitting cam means, a ball, a roller bearing roller (preferably a barrel type or a taper type) or the like can be used, but the one using a ball is an example.

The torque cam damper 1 of the present invention is fixed, for example, downstream of the propeller shaft in the perspective view of the drive system shown in FIG.

In the sectional view of the present invention shown in FIG. 1, a propeller shaft (not shown) is connected to an input flange 2, and the input flange 2 is spline-fitted with a center shaft 3. The center shaft 3 has a spline. Fitted drive cams 4, 5 are provided. The drive cams 4 and 5 are substantially circular members whose central portion is hollowed out and have a structure capable of sliding in the axial direction.

A plurality of concave surfaces are formed on a part of both side surfaces in the axial direction of the drive cams 4, 5 at equal intervals in the circumferential direction, and substantially spherical balls 6, 7, 8, 9 are formed on the concave surfaces. The driven cams 10, 11, 12, which are in contact with each other, and whose surfaces contacting the balls 6 to 9 are concave on the opposite sides of the drive cams 4 and 5 via the balls 6 to 9,
13 is provided, and the driven cams 10 to 13 are substantially circular members whose central portion is hollowed out. Among the four driven cams, the two driven cams 10 and 12 are slidable in the axial direction.

On both sides of the drive cam 4, the ball 6 and the driven cam 10 and the ball 7 and the driven cam 11 are arranged symmetrically with the center plane orthogonal to the axis of the drive cam 4 as a center line. 8 and the driven cam 12 and the ball 9 and the driven cam 13 are arranged symmetrically with the drive cam 5 as the center line. The balls 6 to 9 are held in the radial direction by ring-shaped ball holding members 4c and 4d that form a band in the circumferential direction.

The slidable driven cam 10 is an elastic member case 1 made of a hollow and annular substantially cylindrical member having elastic members 14a and 14b such as coil springs inside.
5 is in contact with the axial end face of 5, and the elastic member case 15 is
Two annular substantially cylindrical portions 15 whose openings face each other
a, 15b, and the outer circumference of one cylindrical portion 15b is slidably in contact with the inner circumference of the other cylindrical portion 15a so that it can expand and contract in response to the compression movement of the elastic member.

By the elastic member 14 provided in the elastic member case 15, the balls 6 and 7 and the driven cam 1 are provided.
Reference numerals 0 and 11 are pressed against the drive cam 4, and the balls 8 and 9 and the driven cam 12, which are similarly arranged on the opposite side of the elastic member case 15 on the rotating shaft,
13 is also pressed against the drive cam 5.

The outer circumferences of the driven cams 10 to 13 are engaged with the outer cylinder 16 by serration, and the outer cylinder 16 having a substantially cylindrical shape is held by the bearing 2a so as to be rotatable in the circumferential direction with respect to the input flange 2. ing. An output flange 17 fixed to the right end of the outer cylinder 16 by welding.
b is provided, and the output flange 17b is a substantially circular member having a structure that closes one end of the present apparatus having a cylindrical shape. A differential device (not shown) is connected to the output flange 17b via a shaft to drive the rear wheels.

The balls 6-9 and the elastic member 14 are
A plurality of members are arranged at equal intervals in the circumferential direction. The balls 6 to 9 are arranged as shown in the ball layout diagram of FIG. 2, and the elastic member 14 in the elastic member case 15 is
It is arranged as shown in FIG.

As shown in FIG. 1, the ball 19 is a ball support member 2 which is axially slidably connected to an outer cylinder 16.
0 is in contact with at least one cam surface 20a,
It is held by a holding member 21 ′ that surrounds the center shaft 3. The ball holding member 21 holds the ball 19 movably in the radial direction.

The torque cam damper of the present invention having the above-described structure has the following actions. That is, the rotational torque transmitted from the transmission to the propeller shaft is input to the input flange 2 of the present device, and the rotational torque input to the input flange 2 is applied to the center shaft 3 and the drive cam 4, which are serrated.
5 is transmitted.

The drive cam 4 is driven by the axial biasing force of the elastic member 14 provided in the elastic member case 15.
Since the balls 5, 6 to 9 and the driven cams 10 to 13 are pressed against each other, the rotational force applied to the drive cams 4 and 5 is transmitted to the driven cams 10 to 13 via the balls 6 to 9 and is spline-coupled. It is transmitted to the cylinder 16 and output to the differential device that drives the rear wheels through the output flange 17b.

As shown in the sectional view of FIG. 5A, when the propeller shaft is rotating with a constant rotational force, the balls 6, 7 are driven by the drive cam 4 and the driven cam by the urging force of the elastic member 14. Cam surface 4 which is each concave surface of 10 and 11
It is engaged with the center of a, 10a, 11a.

However, if a high torque is applied to the propeller shaft due to sudden acceleration and the rotational force fluctuates against the urging force of the elastic member 14, as shown in FIG. The drive cam 4 and the driven cams 10 and 1 are driven by the rolling action of the balls 6 and 7 in the rotating direction for a moment.
It is slid in the axial direction so that the gap with 1 becomes large. At this time, the driven cam 11 is not slid in the axial direction because the end surface of the driven cam 11 is in contact with the fixed member 26a locked to the outer cylinder, and the drive cam 4 and the driven cam 10 slide in the direction in which the elastic member 14 is compressed. To do. Similarly, the drive cam 5, the balls 8 and 9 and the driven cams 12 and 13 provided on the opposite side of the elastic member 4 operate in the same manner.

Therefore, a large momentary fluctuation of the rotational force is not transmitted to the outer cylinder 16 but absorbed by the elastic member 14 as its compression energy, the fluctuation of the rotational force is buffered, and the rotational torque is changed. The vibration and noise transmitted to the vehicle can be reduced because the vibration is smoothly transmitted to the outer cylinder 16 and no sudden torsional vibration occurs. Conversely, when rotational vibration due to sudden braking etc. occurs from the output flange side (but in the opposite direction), the rotational vibration from the output side is absorbed in the same way, and the smoothed torque change on the input side. Is transmitted. The relationship is conceptually shown in FIG.

Further, the twisting characteristic changing means 22 is held on the right end surface of the elastic member case 15 so as to be slidable in the axial direction with respect to the outer cylinder 16 via serrations and being positionally restrained in the circumferential direction. The ball 19 is held by a holding member 21 ′ that abuts on both sides of the ball supporting member 20 held by the outer cylinder 16 and surrounds the center shaft 3. The ball contact surface 20a of the ball support member 20 forms a tapered cam surface whose interval is narrowed radially outward.

At the time of rotation, the centrifugal force acting on the ball 19 in the radial direction increases in proportion to the increase in the number of rotations. Therefore, in the high rotation speed region, the ball 19 causes the ball support member 20 to rotate about its axis. A force that spreads in a parallel direction acts.

At this time, the ball support member 20 is expanded and the elastic member case 15 arranged on the left side in FIG.
Will be pressed in the axial direction.

For this reason, the elastic member 1 responds to the increase in rotation.
The spring set load of 4 (14a, 14b) is increased, and the buffering mechanism that operates even at low rotational torque fluctuations at low rotational speeds, and the buffering operation at small rotational torque fluctuations at high rotational speeds can operate. Be deterred.

In FIG. 8, the characteristic curve of the torsional angle versus the torsional torque, which is provided with the torsional characteristic changing means 22 of the present invention, is conceptually plotted by a broken line. In the figure, the solid line is a plot of the characteristic curve of twist angle versus twist torque of the present invention without the twist characteristic varying means 22.

In FIG. 8, the torsional characteristic in which the spring set load is increased corresponding to the increase in the rotational speed by the above-mentioned torsional characteristic changing means 22 of the present invention is shown by a broken line as an example when the rotational speed is 2000 rpm. There is. In this case, as shown in the figure, in the high rotation speed region, the spring set load of the elastic member 14 increases, so that the shock absorber is provided in the region of small twist angle (that is, the lower region of the broken line in FIG. 8) corresponding to the low rotation torque fluctuation. Is not activated.

Since the torque cam damper of the present invention is provided with the cam means for converting the fluctuation of the rotational torque into the fluctuation in the axial direction at both ends of the elastic member 14, as compared with the case where one cam means is provided on one side. Therefore, it is possible to cope with twice the torque fluctuation. That is, for example, when the rotational angle deviation of the drive cam 4 due to the fluctuation of the rotational torque is the same, the amount of contraction of the elastic member 14 is doubled by providing the cam means on both sides,
This means that the drive cam 4 is twice as biased. In order to resist this urging force, it is necessary to double the torque fluctuation, and it is necessary to double the torque with the same rotation angle deviation, which means that the rotation angle range for absorbing the torsional vibration is limited to the same range. If it is assumed that the torque fluctuation is doubled, it means that the torque fluctuation can be absorbed twice.

According to the present invention, since the balls are provided at four places, a torque cam damper which can deal with a torque fluctuation four times that of one ball and is particularly effective for a four-wheel vehicle in which a high torque fluctuation occurs. Is.

FIG. 6 shows drive cams 4 and 5 provided with stopper means, and is a cross-sectional view showing a state of engagement between the drive cams 4 and 5 and the outer cylinder 16 (partial cross section DD 'in FIG. 1). ). Side wall surface 16a of the serration groove of the outer cylinder 16
Drive cam 4, which engages with a predetermined play angle α, α,
A stopper is formed between the outer periphery of the outer peripheral surface of the groove 5 and the serration protrusion. When the stopper abuts, the whole unit rotates together.
As a result, the device is protected against the rotational torque exceeding the allowable absorption torque range.

In the figure, the outer serration projections of the drive cams 4 and 5 and the serration groove of the outer cylinder 16 are provided with play angles α on their tooth surfaces, so that the propeller shaft rotates with a constant low rotational force. As shown in the figure, since the gaps on both sides of the tooth surface are the same, the rotational force from the propeller shaft is transmitted from the drive cams 4, 5 to the outer cylinder 16 without bidirectional twisting, and the drive is performed. Cam 4,
5 is transmitted to the driven cams 10 to 13 via the balls 6 to 9 and is transmitted to the outer cylinder 16.

When a high torque is applied to the drive cams 4 and 5, the drive cams 4 and 5 are displaced in the circumferential direction, but if the rotation is changed at that time, the balls are further displaced to some extent, and the elastic member is interposed therebetween. It stops where it is balanced by the compressive force of 14 and is locked there. When the drive cams 4 and 5 rotate too much, it is possible to prevent the balls 6 to 9 from coming out of the concave surface of the cam side surface due to the contact of the stoppers, and the drive cams 4 and 5 are provided with stopper means. As a result, there is no need to provide a dedicated stopper means, which helps reduce costs.

FIG. 7 shows a sectional view of an embodiment in which the angle of the cam surface contacting the balls 6 to 9 is gradually increased.

In the cam surface as shown in FIG. 7, the characteristics of torsion angle versus torsion torque are as shown in FIG. 8, and the ratio of the torsion torque to the torsion angle increases at each changing point of the cam surface angle. To go.

In the low torque rotation fluctuation, the amount of sliding of the cam in the axial direction is small, so the torsional vibration absorption by the elastic member 14 is small, but the torsional vibration absorption due to the high torque rotation fluctuation is large, and in the high torque region. It is possible to improve responsiveness in absorbing torsional vibration. The ratio of the torsional torque to the torsional angle increases with each change point of the cam surface angle.

FIG. 1 shows a structure in which one torsion characteristic varying means for the elastic member utilizing the centrifugal force composed of the ball 10, the ball supporting member 20, and the ball holding member 21 is provided in the axial direction. However, by providing a plurality of these in series in the axial direction, the spring set load can be increased while maintaining the same radial dimension.

FIG. 9 shows the damping characteristic of the torsional vibration in the torque cam damper of the present invention. As shown in the figure, it has a damping effect for a wide range of frequencies, and the present invention is useful as a device for absorbing high-torque torsional vibrations.

[0044]

As described above, in the torque cam damper of the present invention, since the cam means is provided on both sides of the elastic member, the rotational torque can be transmitted in a well-balanced manner, and the outer diameter of this device can be increased. It is possible to absorb torsional vibration of high torque without any action, and at the time of rotation, centrifugal force acts on the ball in the radial direction to move the ball support member in the axial direction, and by pressing the elastic member, the spring set load is applied. Is provided to change the torsional characteristic, and has an advantage that the buffering operation of the torque cam damper can be suppressed against a low rotational torque fluctuation in the high rotational speed region.

Further, in the torque cam damper according to the second aspect of the invention, since the balls are arranged on both sides of the drive cam as the cam means and the number of balls is large, the torsional vibration of higher torque can be achieved without increasing the outer diameter dimension. Can be absorbed.

Further, in the torque cam damper according to the third aspect, since the rotation angle of the drive cam can be locked at a predetermined position, the device is protected against the rotation torque exceeding the allowable absorption torque range and the exclusive use. It is not necessary to provide the stopper means of the above, which helps reduce the cost.

Further, in the torque cam damper according to the fourth aspect, by providing a plurality of torsion characteristic varying means in the axial direction, the amount of increase in the spring set load corresponding to the number of revolutions while keeping the same radial dimension ( This has the advantage that the offset) can be further increased.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view taken along the line AA ′ in FIG. 2 showing an embodiment of a torque cam damper provided with a twisting characteristic varying means of the present invention.

FIG. 2 is a radial schematic configuration diagram showing the arrangement of balls in the present invention.

FIG. 3 is a horizontal cross-sectional view taken along the line CC ′ of FIG. 1, showing a schematic cross-sectional view showing the arrangement of elastic members in an elastic member case.

FIG. 4 is a perspective view of a drive system of a vehicle.

FIG. 5 is a B- showing the engagement arrangement of the cam means in the present invention.
B'sectional view.

FIG. 6 is a partial cross-sectional view taken along the line DD ′ in FIG. 1 of the drive cam provided with the stopper means according to the present invention.

FIG. 7 is an explanatory view showing the shape of a torque cam according to the present invention.

FIG. 8 is a characteristic diagram of twist angle versus twist torque in the present invention.

FIG. 9 is a diagram showing a first order frequency of meshing in the present invention versus a torsional vibration level of a gear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Torque cam damper of the present invention 2 Input flange 3 Center shaft 4, 5 Drive (driving) cam 6, 7, 8, 9 Ball (rotating body) 10, 11, 12, 13 Driven (driven) cam 14 Elastic member 15 Elastic Member case 16 Outer cylinder 17b Output flange 19 Ball 20 Ball support member 20a Cam surface 21 Ball holding member 22 Torsional characteristic varying means

Claims (4)

[Claims] Claim: What is claimed is: 1. A torque cam damper for buffering transmission of rotational torque fluctuation to an outer cylinder by converting fluctuation of rotational torque applied to a center shaft into axial fluctuation by a cam means. A cam means arranged in engagement with each other, and an elastic member urged toward the cam means, the cam means being arranged in engagement on both axial sides of the elastic member, and a ball and the ball. And a ball supporting member that has a cam surface that abuts on at least one surface thereof and that is movably arranged in the axial direction, and a ball holding member that movably holds the ball in the radial direction. And a torsion characteristic changing means for changing the spring set load of the elastic member according to the number of revolutions through axial movement of the ball support member in accordance with the centrifugal force applied to the ball support member. Torque cam damper. 2. The cam means comprises a drive cam, a rotating body and a driven cam, and the driven cam via the rotating body engages with both sides of the driving cam in the axial direction. The torque cam damper according to claim 1, wherein the torque cam damper is arranged. 3. The drive cam rotates integrally with the center shaft and is arranged to be rotatable relative to the outer cylinder within a predetermined angle, and a stopper for preventing relative rotation between the drive cam and the outer cylinder. The torque cam damper according to claim 1 or 2, wherein the torque cam damper has a play angle of the predetermined angle between the drive cam and the outer cylinder. 4. The torque cam damper according to claim 1, wherein a plurality of the twist characteristic varying means are arranged in series in the axial direction.