GB2138105A - Damper disc - Google Patents

Abstract

A damper disc includes a spring 12a compressed in an approximately circumferential direction and has a non-linear characteristic being interposed between a window hole 9 in an annular flange 3 of a spline hub 2 and window holes on two integrally formed side plates sandwiching freely rotatably the annular flange. The spring is made of plate or strip material such as of the coned disc 12b or volute type. The arrangement thereby provides a wide torsion angle by providing a torsion spring which affords a long compression stroke. <IMAGE>

Description

SPECIFICATION Damper disc This invention relates to a damper disc which is particularly but not exclusively suitable for a clutch disc for use in an automobile.

For a conventional torsion spring of a damper disc, it is known to provide a coil spring having a non-linear characteristic, two portions of which spring have different compression characteristics respectively, for instance, as shown in Fig. 1 of the accompanying drawings. However, the cross-section of a wire rod used for the coil spring is of circular configuration in the above conventional construction, so that there is a disadvantage that the compression stroke obtainable therewith is not sufficient for the spring to fully adapt to the increased torsion angles which tend to be used in such damper discs nowadays.

In consideration of the above problem, an object of this invention is to provide a damper disc which has a non-linear compression characteristic, using just a single spring to simplify the construction, and further to obtain a wide torsion angle by providing a torsion spring which affords a long compression stroke by using a spring made of plate or strip.

In order to accomplish the above object, in accordance with this invention, a spring, compressed in an approximately circumferential direction and provided with a non-linear characteristic, is interposed between a window hole on an annular flange of a spline hub and window holes on two integrally formed side plates sandwiching freely rotatably the annular flange from both sides.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a partial side view illustrating a conventional irregular pitch spring; Figure 2 is a part sectional side view illustrating a clutch disc employing a damper disc according to this invention; Fig. 3 is an enlarged fragmentary sectional view taken on the line Ill-Ill of Fig. 2; Figure 4 is a graph diagrammatically illustrating the torsion-angle/torsion-torque characteristic; Figure 5 is a sectional side view illustrating another embodiment; Figure 6 is a view similar to Fig. 5, but showing yet a further embodiment; and Figure 7 is a view similar to Figs. 5 and 6, but showing another embodiment.

Referring firstly to Fig. 2, this figure is a partially sectional vertical side view of a damper disc employed, for instance, in a clutch disc for use in a automobile. A splined hub 1 has, on its inner peripheral surface, a spline 2 fitting onto an output shaft (not shown) and has integrally, on its outer peripheral surface, an annular flange 3.

Hysteresis torque-generating portions 4 and 5, such as friction washers or the like, are disposed along the inner peripheries of both sides of the flange 3, and a pair of annular side plates 6 and 7 (namely a clutch plate and a retaining plate respectively) are disposed on opposite sides of the flange 3, sandwiching said torque generating portions 4 and 5.

Plural window holes 9, 10 and 11 (of which one each only is shown) are arranged at positions near to outer peripheries of the flange 3 and the two places 6 and 7 respectively with a spacing therebetween in the circumferential direction of the clutch disc.

The window holes 9, 10 and 11 oppose each other in the direction parallel to the centre axis of the output shaft (i.e. the lateral direction of Fig. 2), and a respective torsion spring 12 fits in each set of three window holes 9, 10 and 11. Each spring 1 2 is so disposed as to be compressed in an approximately circumferential direction, and the flange 3 and the two plates 6 and 7 are elastically interconnected through the spring 1 2. The outer peripheries of the two plates 6 and 7 are integrally connected by a stop pin 8. A cushioning plate 1 3 is fixed to the outer periphery of one side plate 6 (the clutch plate), and annular facings 14 are fastened to both sides of the plate 1 3.

Among the plural window holes 10 (similarly to the window hole 11), parts of window holes 1 Oa are shorter in length in the rotational direction than the window hole 9 as shown in Fig. 3, so that there exist distances L1, L2 in a free state between rotating directional end faces of a coil spring 1 2a (an example of the torsion spring 12) fitted in the window 10a and the window hole 9. On the otjer hand, a window hole lOb coincides with the window hole 9 in the free state viewing in the direction of Fig. 3, a plurality of coned disc springs 1 2b (an example of the torsion spring 12) aligned in a approximately circumferential direction is fitted alternately in the window holes 9, lOb, and coned disc springs 1 2b at both ends contact with both rotating directional end faces of the window holes 9 and 10b.

The operation of the damper disc is as follows. In Fig. 2, when the facing 14 is pressed against a flywheel (not shown) on an engine by means of a pressure plate (not shown in the figure) torque is transmitted from the flywheel through the facing 14, the plate 13, the plates 6 and 7, the spring 12, the flange 3, and the hub 1 to the output shaft.

Here, if a torsion torque is produced in the direction of the arrow X1 of Fig. 3, for example, due to engine torque vibration in the facing 1 4 in relation to the splined hub 1; then the side plate 7 applied with the torque in the direction of the arrow Xl of Fig. 3 will rotate (deflect) in the direction of X, in relation to the flange 3; thus compression of the coned disc spring 1 2b will be commenced first. This compression only of the coned disc spring 12bwill continue until spacing L, vanishes to cause the coil spring 1 2a to contact with the window hole 9, and the characteristic of torsion-angle A torsion-torque T therebetween will be such as the curve between 0 and e1 in Fig. 4.In particular, the characteristic curve perculiar to the coned disc spring is presented in this range, and the torsion torque does not increase so much as compared with an increase in the torsion angle.

When the distance L, of Fig. 3 vanishes to cause the spring 1 2a contact with the window hole 9, the spring 1 2a will become compressed in addition to the compression of the coned disc spring 12b, and the characteristic of torsion-angie A/torsion-torque T will be such as the curve between Oi and 62 in Fig.

4. Further, at the torsion angle 92, the stop pin 8 of Fig. 3. contacts with an outer peripheral notch 3a of the flange 3 to unite the side plate 7 and the flange 3 into a unit.

Since the coned disc spring 1 2b is used here as the torsion spring 12 compressed at the first stage, its thickness is small as compared with the case where only an ordinary coil spring composed of a wire rod having a circular section is used, and moreover a larger compression stroke is obtainable by that margin. Consequently, the window holes 9 and lOb can be made smaller so that strengths of the side plate 7(6) and the flange 3 can be secured.

Incidentally, when the side plate comes back from the maximum torsion angle H2, it functions in the reverse order to present the same characteristic. When the side plate rotates in the direction opposite to the arrow X, in Fig. 3, the same characteristic as rotating in the direction of the arrow X, is presented except that the plate functions to lessen the distance L2 in place of L1. Further, when the damper disc is distorted, a hysteresis torque will be produced to absorb torque vibration due to friction on surfaces of the hysteresis torque generating portions 4, 5 of Fig. 2.

However, an indication of the hysteresis torque is omitted in Fig. 4.

As described above, according to this invention, the spring made of plate or strip (for example the coned disc spring 1 2b) compressed in the approximately circumferential direction and having a non-linear characteristic is interposed between the window hole 9 on the annular flange 3 of the spline hub 1 and the window holes lOb on two integrally formed side plates 6 and 7 sandwiching, freely rotatably, the annular flange 3 from both sides, so that not only is the non-linear compression characteristic obtainable with one kind of a spring to simplify the construction, but the compression stroke can be taken long.

Therefore, the present invention has the advantages that the torsion angle can be enlarged without widening the window holes 9 and 1 0b and that the torque vibration adsorption characteristic can be improved and plate strengths can be maintained.

According to the above embodiment, there is an advantage that the adbsorption characteristic of a fine torque vibration can be improved because an increase of torsion torque in a low torsion angle region can be confined by utilizing the compression characteristic of the coned disc spring 1 2b.

When embodying this invention, the coned disc spring 1 2b may be compressively fitted in the window hole 1 0a as shown in Fig. 3 and the coil spring 1 2a may be compressively fitted in the window hole lob. In this instance, the compression characteristic peculiar to the coned disc spring 1 2b will be exhibited when the torsion angle becomes large. Further, when the torsion spring is composed only of the coned disc spring 1 2b excluding the coil spring 1 2a, a further complex torsionangle A/torsion-torque T characteristic may be obtained. Moreover, the coil spring 1 2a and the coned disc spring 1 2b may be combined together to be fitted in a set of the window holes 9, 10, 11 as shown in fig. 5.

In this instance, the coned disc spring 1 2b may also be assembled therein as shown in Fig. 6.

Furthermore, a volute spring 1 5 as shown in Fig. 7 may be fitted in a set of the window holes 9, 10 and 11 through the means of receiver seats 1 6 and 1 7 and the coil spring 12a.

Claims (4)

1. A damper disc including a spring compressed in an approximately circumferential direction and having a non-linear characteristic said spring being interposed between a window hole on an annular flange of a spline hub and window holes on two integrally formed side plates sandwiching freely rotatably, the annular flange from both sides.

2. A damper disc as claimed in claim 1, wherein the spring comprises a coned disc spring.

3. A damper disc as claimed in claim 1, wherein the spring comprises a combination of a coned disc spring or a volute spring and a coil spring.

4. A damper disc substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.