Torsion spring type damper disc

A damper disc having torsion springs in series in window holes formed in the input side plate and outlet plate, a support structure disposed between the torsion springs composed of a pair of spring receiving members rotatably linked by a hinge part, and a sub-torsion spring compressively disposed between the spring receiving members and hinged apart with an annular linkage element for preventing outward projection in a radial direction by centrifugal force.

DESCRIPTION 
1. Technical Field 
This invention relates to a damper disc having plural torsion springs 
arranged in series in one window hole. 
2. Background Art 
This kind of damper disc has two torsion springs disposed in series in a 
window hole in order to maintain a wide torsional angle range. A support 
member is intervening between the torsion springs in a manner free to move 
in the circumferential direction. 
The present applicant, in the damper disc of the spring series type, as 
mentioned above, previously developed a structure of linking floats with 
an annular linkage element to prevent the support members from projection 
outward in the radial direction by centrifugal force, and filed 
applications (the Japanese Utility Model Applications Sho. 63-38836, Sho. 
63-84777). 
In the conventional damper disc, as shown in FIG. 6, herein, a support 
member 55 occupies a relatively large space in a window hole 16. The space 
in the window hole 16 can not be used economically and effectively even if 
the window hole 16 is formed in an extended circumferential length in 
order to obtain wide torsional ranges. 
OBJECT OF INVENTION 
An object of the invention is to increase the number of springs disposed in 
series in a window hole, to maintain a wider torsional angle range, or 
increase the energy generated in the damper area, by effectively utilizing 
the space for disposing the support member for disposing sub-torsion 
springs. 
DISCLOSURE OF THE INVENTION 
Technical Means 
In order to accomplish above object, the invention presents a damper disc 
forming plural window holes, respectively, in a pair of input side plates 
and an output plate placed between the side plates, and disposing torsion 
springs in series in the window holes in a manner free to compress in the 
circumferential direction. Two torsion springs are disposed before and 
after in the circumferential direction in the window hole, and a spring 
support structure movable in the circumferential direction is intervening 
between the two torsion springs. A pair of spring receiving members, as 
spring support structure, are rotatably linked, through a hinge part, so 
that the gap in their circumferential direction may be freely reduced. A 
sub-torsion spring is compressively disposed between the two spring 
receiving members, thereby supporting each hinge part to an annular 
linkage element. 
Operation of the Invention 
When the input side plates are twisted to the output plate, while 
traveling, the gap of the two spring receiving members is reduced, and the 
sub-torsion spring is compressed. In succession, or at the same time, the 
two series torsion springs, at both sides, are compressed. In the 
cmpression stroke of the two torsion springs, the support structure moves 
in the circumferential direction. 
At this time, each support structure has the internal circumferential end 
portion linked integrally by the annular linkage element, so that it will 
not contact with the peripheral edge of the window hole by projecting 
outward in the radial direction due to centrifugal force.

BEST MODE FOR CARRYING OUT THE INVENTION 
In FIG. 2 showing a longitudinal sectional view of a damper disc according 
to the invention (a sectional view of II--II of FIG. 1), an output spline 
hub 1 is fitted with spline to an output shaft (not shown), and a flange 
(output plate) 2 extending outward in the radial direction. On both sides 
of the flange 2, in its axial direction, a pair of input side plates 3 are 
disposed and are coupled together with rivets 8 at their outer 
circumferential end portions. At the outer circumferential end portion of 
one side plate 3, plural cushioning plates 5 are affixed. Input facings 6 
are affixed to opposite sides of cushioning plates 5. The input facings 6 
are placed, for example, between flywheel and pressure plate, and a 
rotating force is applied. 
Between the inner circumferential side part of both side surfaces of the 
flange 2 and the inner circumferential side part of each side plate 3, 
annular friction members 10 are disposed. Between one friction member 10 
and the side plate 3, a holding plate 11 and a belleville spring 12 are 
disposed. 
A torsion spring window hole 16 is formed in the flange 2. Correspondingly, 
a torsion spring window hole 17 is also formed in side plates 3. Torsion 
springs 18 are disposed in the window hole 16, 17 in a manner free to 
compress in the circumferential direction. 
In FIG. 1, window holes 16, in the flange 2, are formed at three positions 
at equal intervals in the circumferential direction. Two torsion springs 
18 are compressively disposed in series, before and after in the 
circumferential direction, in each window hole 16. Between the front and 
rear torsion springs 18, in the window hole 16, a support structure 20 is 
disposed movably in the circumferential direction. This torsion spring 18 
is of master-slave spring type, with a slave spring 19 provided inside. 
The window holes 17, in the side plates 3, are formed at three positions at 
equal intervals in the circumferential direction, corresponding to the 
arrangement of the window holes 16 in the flange 2. 
The support structure 20 is composed of a pair of front and rear spring 
receiving members 22, spaced in the circumferential direction. The inner 
end portions, in the radial direction, of each spring received member 22 
mutually extend to the opposite side members. At their front ends, pin 
boss parts 21 parallel to each output shaft center, are formed integrally 
on each of the side members. The pin boss parts 21 are fitted to a common 
pin 25, rotatably linking spring receiving members 22. By this rotation, 
the circumferential gap of the two spring receiving members 22 can be 
reduced. 
Three pins 25, one for each support structure, are supported on an annular 
linkage element 30 coaxial with the clutch shaft center, so that the 
support structures 20, at three positions, can move in the circumferential 
direction, simultaneouly by the same angle, without pojecting outward in 
the radial direction. 
Between spring receive members 22, a sub-torsion spring 21 is disposed 
compressively in the circumferential direction. In this embodiment, the 
sub-torsion spring 27 has a weaker spring force than the front and rear 
torsion springs 18 so as to act as the damper member of the first stage. 
FIG. 3 shows a perspective view of the support structure 20, in which each 
spring receive member 22 is formed in a circular shape so as to support 
the entire end portion of the torsion spring 18, a cylindrical protrusion 
26 is formed in the middle part to project mutually to the opposite side 
of the confronting spring receiving member, and partially arc-shaped 
stopper/spring guide part 28 extending mutually to the opposite side 
member is integrally formed at the outer end portion in the radial 
direction. 
The operation is described below. By the increase of rotating torque, when 
the side plates 3 are twisted to the side of the rotating direction R in 
the FIG. 1, for example, with respect to the flange 2, the spring 
receiving members 22 of each support structure 20 rotate about the pin 25 
to approach each other, thereby compressing the sub torsion spring 27 as 
the first stage. When the stopper/spring guide parts 28 of each spring 
receiving members 22 abut against each other, further compression of 
sub-torsion spring 27 is terminated, and the front and rear torsion 
springs 18 are compressed as the second stage. In the compression stroke 
of the torsion spring 18, the support structure 20 in FIG. 1 moves in the 
direction of rotation R. By adjusting the set load of the springs 18, 27, 
three springs 18,27 can be compressed in the first stage, and only two 
torsion springs 18 can be compressed in the second stage. 
In said torsion action, as the friction member 10, FIG. 2 makes contact, 
hysteresis torque is built up. Because the three support structures 20 are 
linked by the annular linkage members 30, they do not project outward in 
the radial direction. 
OTHER EMBODIMENTS 
FIG. 4 relates to an example of applying the invention to a so-called split 
hub type damper disk, that is, the flange (output plate) 2 of the spline 
hub is divided into an inner flange part 2a and an outer flange part 2b. 
In the inner flange part 2a, a window hole (notch) 36 for the first stage 
is formed, and a bifurcate expanding part 2c is formed in the inner end 
part of the outer flange part 2b so as to cover the both sides in the 
axial direction of the inner flange part 2a. A window hole 37 for the 
first stage corresponding to the window hole 36 in the inner flange part 
2a is formed in expanding part 2c. 
In the window holes 36, 37, first stage torsion springs 38 of small spring 
contact are disposed compressively in the circumferential direction. 
In the inner edge of the outer flange part 2b and outer edge of the inner 
flange part 2a, a convex part 51 and a concave part 50 mutually engagable 
with each other, are formed at a spacing in the circumferential direction. 
Between the expanding part 2c of the outer flange part 2b and opposite 
sides of the inner flange part 2a, friction members 39 for the first stage 
with small frictional coefficient are disposed, and between the expanding 
part 2c and opposite side plates 3, friction members 40 for the second and 
third stages with large frictional coefficient are disposed. In this 
embodiment, the sub-torsion springs 27 are stronger than the first stage 
torsion springs 38, and are set, for example, at the same strength as the 
front and rear torsion springs 18. 
The outer structure is same as in the form in FIG. 1, and the same parts 
are indentified with the same members. 
The operation is described below. In the first stage (For example, when 
idling), the outer flange part 2b and side plates 3 are integrally twisted 
to the inner flange part 2a, for example, to the rotating direction R 
side, thereby compressing the first stage torsion springs 38. At this 
time, as the expanding part 2c of the outer flange part 2b and the first 
stage friction member 39 between the opposite sides of the inner flange 
part 2a contact with each other, a small hysteresis torque is built up. 
Changing from idling to low speed traveling, as the torsional torque 
increases, the concave part 50 of the inner flange part 2a and the convex 
part 51 of the outer flange part 2b join to couple the both flange parts 
2a, 2b into one body, and, in the second stage, the side plates 3 are 
twisted to the rotating direction R, thereby simultaneously compressing 
the three springs in series, that is the torsion spring 18 and 19 and 
sub-torsion spring 27. In the compression stroke of the second stage, the 
gap between the both spring receiving members 22 is narrowed, and the 
support structure 20 moves in the rotating direction R. At this time, as 
the side plates and the second stage friction member 40 in the expanding 
part 2c of the outer flange part 2b contact with each other, a relatively 
large hysteresis is generated. 
When the stopper/spring guide parts 28 of the both spring receiving parts 
22 abut against each other, further compression of the sub-torsion spring 
27 is over, and, in the third stage, only the front and rear torsion 
springs 18, 19 are compressed. In this process of the third stage, the 
spring constant of the three series springs is changed to the spring 
contact of two series springs, 18, 19 and therefore the spring strength is 
greater than in the second stage. 
FIG. 5 shows the torsional characteristic in the embodiment in FIG. 4, in 
which the axis of ordinates T denotes the torque, and the axis of 
abscissas relates to the torsional angle. The torsional angle 0 to 
.THETA.1 refers to the first stage, and .THETA.1 to .THETA.2 to the second 
stage, and .THETA.2 to .THETA.3 to the third stage. 
In the split hub type structure, as shown in FIG. 4, the sub torsion spring 
27, stronger than the first stage torsion spring 38, may be replaced by a 
spring weaker than the torsion spring 18 or the sub torsion spring 27 may 
be replaced by a spring stronger than the torsion spring 18. 
In both the first and second embodiments, final compression of the 
sub-torsion spring 27 occurs when the stopper/spring guide parts 28 of the 
spring receiving members 22 abut against each other, but sub-tension 
spring 27 may also be designed to finish the compression stroke by fully 
compressing the sub-torsion springs 27 before the guide parts 28 abut 
against each other. 
EFFECT OF THE INVENTION 
As decribed herein, the damper disc of the invention disposing springs in 
series in one window hole brings about the following effects: 
(1) A pair of spring receiving members 22 are rotatably linked together 
through a hinge part so that the gap in the circumferential direction may 
be reduced freely, as the support structure disposed between two front and 
rear torsion springs 18, and a sub-torsion spring 27 compressive in the 
circumferential direction and disposed between the two spring receiving 
members 22, so that the number of springs to be disposed in series in one 
window hole may be increased and wider torsional angle may be obtained. 
(2) The space within the support structure 20 is also used as the space for 
installing new sub-torsion spring 27, and it is not necessary to extend 
the circumferential length of the window hole 16 to extend the torsional 
angle, so that increase of size of damper disc and lowering of durability 
may be prevented. 
(3) Further when the torsional angle range is set the same as the torsional 
angle range of the conventional type of two springs in series, the 
increasing rate of the torsional torque is raised, and the energy 
generation may be increased. 
INDUSTRIAL APPLICATION 
The number of springs disposed in series is increased, a wider torsional 
angle is obtained, and compression operation is stabilized, so that it is 
ideal as an autmotive damper disk.