The present invention relates to an apparatus for transmitting torque from a driving shaft to a driven shaft, particularly an crverxunning clutch, which comprises

at least one part, located within the clutch body, fitted with an internal engaging surface, whose center line deviates from the center line of the driving shaft, and with an external engaging surface, whose center line combines with the center line of the driving shaft.

at least one engaging element, the first one on the driving shaft, which, at least when the clutch body is in the engaging position, engages with the internal engaging surface of the part within the clutch body, while said engagement makes the external engaging surface of the part within the clutch body engage with the internal engaging surface of the clutch body, and

at least one engaging element, the second one on the driving shaft, which, when the clutch body is in the disengaging position, engages with the part within the clutch body, and vfaich engaging element, when the clutch body is in the engaging position, is disengaged from the part within the clutch body-

Torque is conventionally transmitted f an a driving shaft to a driven shaft by means of various couplings and clutches. Among mechanical couplings and clutches, in which category the present invention can be classified, we know for instance rigid couplings, movable couplings, flexible couplings, releasing clutches and self-acting clutches. For instance the Finnish Patent No. 55565

describes a device for transmitting torque from a driving shaft to a driven shaft, which device, depending cn its purpose, may act as a releasing clutch, flexible cxupling or a movable coupling. Gener¬ ally speaking, a device in accordance with said publication may act as a mechanical stepless clutch. Said device comprises a clutch body, in which there is a part with an internal tooth ring, which part engages with the clutch body in an engaging situation. On the driving shaft there is a gear that nk≥shes with the internal tooth ring. The internal tooth ring is installed eccentrically with regard to the driving shaft so that vfaen the driving shaft is turned, the gear on the shaft forces the part with the tooth ring move in the direction of the radius of the shaft and engage with the clutch body.

in e device in accordance with said publication there is also another engaging element, with which the device can be engaged in such a way that torque is not transmitted fran the driving shaft to the clutch body; thence torque is not transmitted from the driving shaft to the driven shaft. However, the function of this second engaging element is not automated but has to be engaged separately. Therefore a device in accordance with the publication 55565 cannot work as an automatic csverxunning clutch; instead, for this purpose it has to be fitted with engaging elements, with which the connection can be disengaged.

Accordingly, it is the object of the present invention to provide an apparatus for trar_-_π_itting torque from a driving shaft to a driven shaft, which apparatus may work both as a mechanical stepless clutch and an σve_-_π_nr_ing clutch. An additional object of this - invention is to provide such an apparatus for transmitting torque frαn a driving shaft to a driven shaft whose design is simple and which is not technically difficult to ____nufacture.

The objects of the invention are attained by an apparatus whose principal characteristic feature is that said second engaging element is arranged onto the driving shaft to be moved by ceπtri-

fugal force so that at a certain or higher rotating speed of the driving shaft said second engaging element is arranged to engage with the part within the clutch body, and at a lower rotating speed of the driving shaft said second engaging element is arranged to be disengaged from the part within the clutch body.

Several advantages are attained by an apparatus in accordance with the invention for transmitting torque frαn a driving shaft to a driven shaft, among them the facts that the apparatus is simple and cheap to manufacture, that it can function both as a stepless mechanical clutch and as an over__ur_ning clutch, that it is reliable and virtually non-wearing. The apparatus has a very wide sphere of application as it can be used for instance as a motor vehicle clutch as well as an industricϋ. clutch.

The invention will be described in detail below, with reference to the figures in the ac∞mpanying drawings which illustrate a favour¬ able embodiment of an apparatus in accordance with the invention.

Fig. 1 is a schematic cross section of an embodiment of an apparatus in accordance with the invention.

Fig. 2 shows section view II-II in Fig. 1.

Fig. 3 shows section view III-III in Fig. 1.

Fig. 4 shows a partial section view of another embodiment of the invention.

In the embodiment shown in Figs 1 to 3 the driving shaft is referred to by 11 and the driven shaft is referred to by 12. The center line of the driving shaft 11 is referred to by 13. The apparatus in accordance with the invention comprises a clutch body 10, within which there are, in this embodiment, two eccentric parts 14 and 14a. The part 14 has an internal engaging surface 24, whose center line deviates frαn the center line 13 of the driving shaft 11.

Similarly the part 14a has an internal engaging surface 24a, whose center line also deviates from the center line 13 of the driving shaft 11. In this embodiment the internal engaging surfaces of the parts 14 and 14a are internal cylindrical surfaces, within which needle rings 22 and 22a, respectively, are arranged. The clutch body 10 has an internal engaging surface 20, within which the parts 14 and 14a are installed. The parts 14 and 14a have external engaging surfaces 21 and 21a, respectively. Between the internal engaging surface 20 of the clutch body 10 and the external engaging surfaces of the parts 14 and 14a there is a clearance, which enables the parts 14 and 14a to rotate within the clutch body 10. The space within the clutch body 10 is filled with oil, and the clutch body 10 is of course sealed to prevent oil from leaking out.

in the embodiment of Figs 1 to 3, the two first engaging elements 17 and 17a are installed on the driving shaft 11, which engaging elements, in accordance with the invention, are cylindrical surfaces machined onto the shaft 11 with center lines deviating from the center line 13 of the driving shaft 11. The center line of the first engaging element 17 within the part 14 combines, in the situation illustrated in the figures, with the center line 16 of the internal engaging surface of the part 14, and the center line of the first engaging element 17a within the part 14a combines with the center line 16a of the internal engaging surface 24a of the part 14a. The first engaging elements 17 and 17a have external engaging surfaces 27 and 27a, which, at least when the apparatus is in the engaging position, form, by means of needle rings 22 and 22a, a connection between the internal engaging surfaces 24 and 24a of the parts 14 and 14a. The driving shaft 11 has also another engaging element 18, which in the embodiment illustrated in the figures is a pin loaded by a spring 19. For the coupling pin 18, a suitable slot 28 has been shaped to the part 14a located within the clutch body 10. When the clutch body 10 is disengaged, the coupling pin 18 is engaged with the part 14a within the clutch body 10, but disengaged from the part 14a when the clutch body 10 is in the engaging position. For this purpose the coupling pin 18

is equipped with the spring 19 that pulls the coupling pin 18 from the slot when the clutch body 10 is in the engaging position.

In the em__odir_ent shown in Figs 1 to 3, a flange 30 has been ma¬ chined an the shaft 11 between the first engaging elements 17 and 17a for separating the parts 14 and 14a and the needle rings 22 and 22a from each other. It should however be realized that the two first engaging elements are not necessarily required in an apparatus in accordance with the invention, the apparatus will work with one first engaging element only. Then of course the flange 30 is also unnecessary. On the other hand, an apparatus in accordance with the invention may also have more than two first engaging elements. On the shaft 11 there may of course also be more than one coupling pin 18 and spring 19. As shown in Fig. 1, the driving shaft 11 is supported to the clutch body 10 by means of bearings 32 and 34, of which the first one 32 is a ball bearing and the second one 34 is a roller bearing. The driving shaft 11 may as well be supported by any conventional means.

An apparatus in accordance with the invention (Figs 1 to 3) func¬ tions as follows. When the driving shaft 11 is rotated, the parts 14 and 14a within the clutch body 10 engage, due to the influence of the first engaging elements 17 and 17a, with the internal en¬ gaging surface 20 of the clutch body 10. This is so because there are the needle rings 22 and 22a between the external engaging surfaces 27 and 27a of the first engaging elements 17 and 17a and __ntern_-l engaging surfaces 24 and 24a of the parts 14 and 14a within the clutch body 10, said needle rings 22 and 22a enabling the first engaging elements 17 and 17a to rotate with respect to the parts 14 and 14a within the clutch body 10. As the first en¬ gaging elements 17 and 17a are eccentric with respect to the driving shaft 11, they, when turning around, move the parts 14 and 14a within the clutch body 10 outwards in the direction of the radius. Then the external engaging surfaces 21 and 21a of the parts 14 and 14a within the clutch body 10 contact the internal engaging surf ce 20 of the clutch body 10 resulting in engagement.

The distances between the center line 13. of the driving shaft 11 and the center lines 16 and 16a of the internal engaging surf ces 24 and 24a of the parts 14 and 14a within the clutch body 10 and the clearance between the external engaging surfaces 21 and 21a of the parts 14 and 14a and internal engaging surface 20 of the clutch body 10 determine how fast and flexibly the engagement occurs. If the clearance between the external engaging surfaces 21 and 21a and the internal engaging surface 20 of the clutch body 10 is selected sufficiently small, the contact angle between the parts 14 and 14a within the clutch body and the clutch body 10 can be made even larger than 180°. As, in the embodiment of Figs 1 to 3, there are two first engaging elements 17 and 17a, the contact angle can in this embodiment be when needed made as large as 360°.

T e function of an apparatus in accordance with the invention will now be described by way of an example with reference to Figs 1 to 3, in which the apparatus is installed in a car that has conven¬ tional clutch and transmission. An apparatus in accordance with the invention may be installed in a car for instance between the clutch and the transmission or after the transmission. An apparatus in accordance with the invention can naturally be used not only in motor veihicles but in all types of drive line systems. When the driving shaft 11 is turned, the eccentric first engaging elements

17 and 17a make the parts 14 and 14a within the clutch body 10 engage with the internal engaging surface 20 of the clutch body

10. The second engaging element 18 will now come at the slot 28. When the rotating speed increases, centrifugal force pushes the second engaging element 18 to slot 28. The spring 19 and the second engaging element 18 are so balanced that the second engaging element

18 is fully out for instance when the rotating speed of the driving shaft 11 is directly proportional to the idling speed of the engine. With this kind of arrangement, for instance always after an accel¬ eration, when the accelerator pedal is released and the drive is disengaged frαn the driving shaft 11, which brings the drive to the driven shaft 12, the other engaging element 18 penetrates into the slot 28 and stops parts 14 and 14b within the dutch body 10

1 in the neutral position so that the vehicle begins to coast.

In vehicle use the engine braking is always effected by pressing dcwn the clutch pedal. Then the rotating speed of the driving shaft 11 goes under the idling speed and the spring 19 pulls the second engaging element 18 in. As the drive is still on the driven shaft 12, parts 14 and 14b within the clutch body 10 are engaged with the engaging surface 20 of the clutch body 10 to the engine- braking side. ^" The second engaging element 18 is so dimensioned 0 that, in the retracted position, it remains under the inner peri¬ phery of the part 14a within the clutch body 10. Therefore in order to engage an apparatus in accordance with the invention in the _we-_runn__ng clutch position no special attachments or engaging elements are needed but the engagement takes place fully auto- ' matically.

Fig. 4 shows an alternative embodiment of an apparatus in accordance with the invention. In Fig. 4 the apparatus is installed on the clutch .shaft of a motor vehicle, but the apparatus may of course be used in association with any drive-line shaft. The embodiment shσwn in Fig. 4 is identical with the embodiment shown in Figs 1 to 3 in all respects except the a__r__ngement of the second engaging element 118. In the ernbodiment of Fig. 4 the second engaging element is composed of a coupling pin, for which a suitable slot 128 is

^ shaped to the part 114a within the clutch body 110. When the clut h body 110 is disengaged, the coupling pin 118 engages with the part 114a within the clutch body 110, but when the clutch body 110 engages, the coupling pin 118 is disengaged from the part 114a within the clutch body 110. When the driving shaft is turned, the

30 first engaging elements make the parts 114 and 114a within the clutch body 110 engage with the internal engaging surface of the clutch body 110. The second engaging element 118 then comes at the slot 128. Now centrifugal force pushes the second engaging element 118 into the slot 128. The second engaging element 118 may also be

35 loaded with a spring which helps to push the second engaging element into the slot 128. In order to return the second engaging element

118 into the retracted position, a longitudinal and concentric boring is shaped into the driving shaft 111, into which boring a spindle 152 is arranged. One end 154 of the spindle, the end on the side of the .second engaging element 118, has been shaped as a screw ^* pump. For preventing oil from l__aking the spindle 152 is of course sealed with respect to boring 150 for instance with an 0- ring seal 158. A radial boring 160, reaching from the axial boring 150 to the outer periphery of the driving shaft 111, is drilled to the opposite end of the driving shaft 111. In the embαiiment shown in Fig. 4 the spindle 152 reaches frαn the clutch, body 110 to the flyvdieel 162, to which the spindle 152 has been fastened with an appropriate element 156. Therefore the spindle 152 will always rotate at the same speed as the flywheel 162. The driving shaft 152 is supported in the nor∑ral way to the flywheel 162 with bearing 168. Against flywheel 162 there is a conventional motor vehicle clutch 166, and on the other side of the clutch there is a con¬ ventional clutch assembly 164.

When the vehicle starts moving the clutch 166 is engaged of course, whereat the driving shaft 111 and the spindle 152 rotate together . and at the same speed. The second engaging element 118 is now pushed by centrifugal force possibly assisted by a spring to the protruded position and into the slot 128. The slot 128 has a certain length in the direction of the periphery of the part 114a within the clutch body 110 as shown in Fig. 3. The second engaging element 118 is then able to move in the rotating direction with respect to slot 128, whereat the part 114a within the clutch body 110 (also the other part 114 within the clutch body 110) engages with the internal engaging surface 120 of the clutch body 110. The torque will then be directly transmitted frαn the driving shaft 111 to the driven shaft 112. When the driving shaft 111 is retarded, in other words when the driven shaft 112 becomes the driving shaft and the driving shaft 111 becomes the driven shaft, parts 114a and 114 within the clutch body 110 turn around to the driving direction of the vehicle, whereat the second engaging element 118 hits the edge of the slot 128 and prevents the parts 114 and 114a within

the clutch body 110 frαn engaging with the internal engaging surface 120 of the clutch body 110. Now the apparatus is disengaged, and torque is not transmitted from the driving shaft 111 to the driven shaft 112 or vice versa. When the drive is reengaged to the driving shaft 111, torque will again be transmitted frαn the driving shaft 111 to the driven shaft 112.

For engine braking with an apparatus in accordance with Fig. 4 the procedure is as follows. At first the clutch 166 is disengaged so that the rotating speed of the driving shaft 111 grows higher than the rotating speed of the flywheel 162. Ihe spindle 152 rotates at the same speed as the flywheel 162 so that there is a notable speed difference between the driving .shaft 111 and the spirdle 152. The screw pump shaped to the spindle 152 now creates a vacuum under the second engaging element 118, which vacuum pushes the second engaging element 118 to its inner position. The clutch body 110 is of course filled with oil in the same way as the clutch body 10 of Fig. 1. Therefore the screw pump 154 sucks oil frαn the end where the second engaging element 118 is and pushes it out of the boring 150 through the radial boring 160. When the second engaging element 118 has retracted into its inner position, the parts 114 and 114a within the clutch body 110 engage with the internal engaging surface of the clutch body 110. When the vehicle clutch 166 is now reengaged, the engine brakes the vehicle. The engine will brake until the rotating speed of the flywheel 162 is increased higher than the rotating speed of the driven shaft 112.

The invention has been described with reference to the figures of the accαrrpaπyir_g drawing by way of examples only. The invention is by no means restricted to the embodiments illustrated in the fig¬ ures; several other versions are possible within the framework of the iπventional idea as defined in the following claims.