WO1980002729A1

WO1980002729A1 - Friction wheel device for transmitting,with a continuously variable speed ratio,a rotary motion between two coaxial shafts

Info

Publication number: WO1980002729A1
Application number: PCT/AT1980/000016
Authority: WO
Inventors: R Falkner
Original assignee: R Falkner
Priority date: 1979-06-01
Filing date: 1980-05-23
Publication date: 1980-12-11
Also published as: ATA399679A; IT1149967B; EP0029435A1; AT360811B; IT8022476A0; IT8021940V0; FR2458008A1

Abstract

On a drive shaft (1) there is mounted a drive member (2) which is integral in rotation with this shaft, but radially and axially displaceable; a disk (3) is rotatingly mounted on the driving member (2) through a roller bearing (21) and carries a friction ring (4) presenting four conical transmission surfaces (30, 31). The transmission surfaces (30) of the friction ring (4) roll on the transmission surfaces (33) of two friction crowns (7, 8) of a friction wheel (6) integral with the casing and the transmission surfaces (31) roll on transmission surfaces (34) of two friction crowns (10, 11) of a second friction wheel (9) mounted on the driven shaft (12), concentrically to the friction wheel (6). The spacing of the friction crowns (7, 8) respectively (10, 11) is variable. During the rotation of the driving shaft (1) the friction ring (4) effects a slow oscillating motion about the driving shaft (1) and transmits this motion to the frictional wheel (9). The two transmission fields are onset by 180 . The excentricity is adjustable between a maximum and O, which allows a reduction up to the infinite.

Description

Friction gear for the continuously variable transmission of a rotary movement between two coaxial shafts

The invention relates to a friction to the infinitely variable transmission of a rotary movement between a driving shaft and a coaxial ^'n output shaft, with a housing-fixed concentric friction wheel having two spaced ih¬ rem axial distance variable Reibkränze each with a transfer surface, and with a in the transmission surface rolling friction ring, which is rotatably mounted on a rotating and radially displaceable driver with the drive shaft, and with an output member between the friction ring and the output shaft.

Characteristic of the known prior art

Such a transmission can be found, for example, in AT-PS 222.966. It has a very large area of application and can in particular also be used wherever, in addition to the requirement for a continuously variable reduction ratio which can be set precisely to infinity, there is only little space available for the installation of the transmission.

However, the known transmission has constructive weaknesses in the transmission of the rotary movement between the radially adjustable friction ring, which is therefore variable in its eccentricity, and the output shaft, which takes place by means of a hollow wobble shaft coupling as the output member. Only when the reduction ratio is infinite does the hollow wobble shaft coupling run concentrically with the output shaft, while in any other position it wobbles, which results in a double cardan joint connection with the friction ring and the output shaft. The radial adjustment of the friction ring inevitably takes place towards the drive shaft by the approach of the two friction rings of the friction wheel fixed to the housing, away from the drive shaft by means of a spring which is prestressed between the drive shaft and the driver. It has been shown that in the transmission of particularly high torques, the spring inserted between the drive shaft and the driver cannot, in particular, exert the necessary contact pressure of the friction ring on the friction wheel if uneven loads occur.

Object of the invention

The invention has now set itself the task of improving the known transmission in its output part and to eliminate a swash shaft coupling with all the disadvantages inherent in it. Furthermore, in a preferred embodiment, an inevitable radial displacement of the driver in both directions is also to be achieved.

State the nature of the invention

According to the invention, this object is achieved in that a second friction wheel, which is concentrically arranged on the output shaft, is provided as the output member, with two friction rings which can be changed in axial distance from one another, each with a transmission surface, on which the friction ring rolls along a second conical transmission surface , wherein the transmission ranges between the friction ring and the first outer and the second inner friction wheel are offset from one another by 180.

The offset of the transmission range by 180 is known from gear transmissions with an eccentrically double-toothed intermediate member, for example from US Pat. No. 546,249.

The eccentrically changeable friction ring is now, on the one hand, as in AT-PS 222.966, with its outward-facing transmission surface in the housing-fixed, concentrated trical friction wheel, but on the other hand, due to the solution according to the invention, it is also forced with its inwardly directed transmission surface into the concentric friction wheel connected to the output shaft. The transmission of the rotational movement between the radially and thus eccentrically shifting friction ring and the second concentric friction wheel takes place directly without an intermediate member, and the axial distance change of the friction rings of the second friction wheel is achieved by its axial coupling with the first outer friction wheel.

It is therefore preferably provided that one friction ring of both friction wheels is axially displaceable, with both friction rings being assigned a common displacement device and an axial roller bearing being arranged between them.

for the inevitable radial adjustment of the driver in both directions, d. H. To change its eccentricity, it is further provided in a preferred embodiment that the driver of the friction ring is assigned an axially displaceable adjusting device, the axial displacement of which moves the driver radially via the articulated lever.

Advantageously, at least one compensating body can be coupled to the articulated levers, which is displaced radially opposite the driver by the adjusting device in order to balance the driver at least statically.

The inventive design of the friction gear also has the further advantage that the mass of the eccentrically variable components is restricted to the friction ring, so that a smaller one is used to compensate for the changing imbalance. counter-changeable balancing mass is required. In addition, the design according to the invention offers the possibility of providing the balancing weights axially on both sides of the friction ring, so that not only a static but also a dynamic balancing. tion can be reached.

OMPI A preferred embodiment of the ^~ invention also avoids large extent the occurrence of tilting moments and thus uneven loads on the Ubertragungsflachen in that the plane of symmetry of the two friction wheels and the friction ring are together.

Description of the drawing figures

The invention will now be described in more detail with reference to the figure of the accompanying drawings in two exemplary embodiments, without being limited thereto.

Show it:

Fig. 1 shows a longitudinal section through a first exemplified embodiment ^"of the invention;

Figure 2 is a longitudinal section through a second game Ausführungsbei.

3 shows the arrangement and position of the counterweights with the friction ring in a central position;

4 shows their arrangement and position with the eccentric position of the friction ring;

Figure 5 shows a longitudinal section through a third game Ausführungsbei.

Fig. 6 is a section along the line VI - VI of Fig. 5; U.N

7 shows a longitudinal section through a fourth exemplary embodiment.

Description of preferred embodiments

1 has a

θλ Drive shaft 1 and a coaxial output shaft 12. A driver 2 is connected in a rotationally fixed manner to the drive shaft 1, but its eccentricity and preferably also axially adjustable. For this purpose, the drive shaft 1 in the area of the driver 2 has a square section 17 which penetrates a recess 18 of the driver 2. The recess 18 has the same width, but a greater length than the square section 17, so that the driver 2 can be displaced in the longitudinal direction of the recess 18. The driver 2 is surrounded by a radial roller bearing 21 on which a cranked disc 3 is rotatably mounted. A friction ring 4 is fastened to the side of the disk 3, said friction ring having four conical transmission surfaces 30, 31 and having a convex octagonal cross section. The two outwardly directed conical transmission surfaces 30 engage between two friction rings 7, 8 of a first, outer friction wheel 6 connected non-rotatably to the housing 5, whereby they interact in one area with the transmission surfaces 33 of the friction rings 7, 8 . The distance between the two friction rings 7, 8 can be changed, which is achieved by axially displacing a friction ring 8.

The two other, inwardly directed, conical transmission surfaces 31 of the friction ring 4 engage in between two friction rings 10, 11 of a second, inner friction wheel 9, which can also be changed at a distance from one another, the transmission surfaces 31 being in a region offset by 180 cooperate with the transmission surfaces 34 of the friction rings 10, 11. In the embodiment shown, in turn a friction ring 10 is axially fixed and the second friction ring 11 is designed to be axially displaceable, the second friction ring 11 being axially displaceable but non-rotatably mounted on a cranked part of the second friction wheel 9.

The second friction wheel 9 is non-rotatably connected to the output shaft 12. The plane of symmetry of both Reib¬ et! R £ Λ o:. * Vι 7- ... ^ 7? Δ ^~~ - wheels 6, 9, and the friction ring 4 lie in one another, so that tilting moments are almost excluded.

The two axially displaceable friction rings 8, 11 are adjustable by a common displacement device 14, 15, 16, an axial roller bearing 13 being arranged between the two friction rings 8, 11, since they rotate relative to one another. The displacement device has an adjusting ring 15 which can be rotated on a thread 14 of an annular extension 32 which is fixed to the housing and surrounds the output shaft 12. The adjusting ring 15 acts on a plurality of pressure bolts 16 which are axially displaceable in the bores 28 of the housing sides 29 and abut on the displaceable friction ring 8 of the outer friction wheel 6 fixed to the housing. The rotation of the adjusting ring 15 brings about a common change in the spacing between the friction rings of the two friction wheels 6, 9.

The eccentric arrangement of the friction ring 4 causes an oscillating movement of the friction ring 4 when the drive shaft 1 is rotated, the outer transmission surfaces 30 of which roll on the transmission surfaces 33 of the friction rings 7, 8 of the outer friction wheel 6, line contact being provided on both sides. The necessary contact pressure is achieved by a device for increasing the eccentricity, which is formed in the embodiment shown in FIG. 1 by a spring 19 which is inserted into the recess 18 of the driver 2, and radially on the square portion 17 of the drive shaft 1 supports. Instead of the spring 19, other parts can also be provided, for example a hydraulically extendable component, an axially displaceable pulling wedge, the movement of the pulling wedge being able to be coupled with the movement of the friction rings or the like 5 and 6 are described. The use of a spring 19 has the advantage in the transmission of not too great torques and uniform loading that the spring, which increases with increasing compression, is reduced by a suitable choice of spring the eccentricity increasing torque to be transmitted is approximately equal.

The movement of the oscillating friction ring 4 is simultaneously transmitted directly to the second, inner friction wheel 9 in the same way, the transmission surfaces 31 of the friction ring 4 rolling on the transmission surfaces 34 of the friction wheel 9. There are therefore no further drive links, and the mass of the eccentrically moving components remains limited on the disk 3 with the friction ring 4.

With the position of the friction ring 4 shown in FIG. 1, an average reduction ratio can be achieved. An enlargement of its distance from the housing side wall 29 which can be achieved by turning the adjusting ring 15 simultaneously increases the distances between the

^• Friction rings 7, 8 and 10, 11 of the two friction wheels 6, 9. The spring 19 increases the eccentricity of the driver 2 and the disk 3, and thus also the friction ring 4, and the friction rings 7, 8 and 10, 11 apart moves, while at the same time providing the necessary pressure on both the outer and the inner friction wheel. There is a slight axial displacement of the friction ring 4. The increase in the eccentricity leads to a reduction in the reduction ratio, which is inversely proportional to the difference in diameter of the outer friction wheel 6 and the friction ring 4.

An approach of the respective friction rings 7, 8 or 10, 11 by turning the adjusting ring 15 presses the friction ring 4 inwards against the spring 19 and reduces its eccentricity. In the extreme case, the eccentricity is zero

Friction ring 4 is encompassed along its entire circumference by both the friction rings 7, 8 and the friction rings 10, 11, so that any relative movement between the three parts is excluded. Since the driver 2 in this case ^ is arranged exactly centrally on the drive shaft 1, this runs freely in the radial roller bearing 21, and the Dre movement of the driver 2 is not transmitted to the disc 3. In this case, the reduction ratio is infinite.

In order to compensate for the unbalance of the changing eccentricity, compensating bodies 23 which can be moved in opposite directions are provided. 3 and 4, the arrangement of the compensating body is shown in the two limit positions. 3 shows the position in which the infinite reduction ratio is given, ie in which there is no imbalance in the driver 2. The compensating bodies 23 are arranged symmetrically to the longitudinal axis of the recess 18 of the driver 2 on levers 22 which cross each other and have elongated holes 25. A displacement of the driver 2 into the position shown in FIG. 4 causes an opposite movement of the two compensating bodies 23 and thus a static balancing of the driver. Dynamic balancing is achieved in that the compensating bodies 22 are arranged axially on both sides of the driver 2.

A slightly different embodiment is shown in FIG. 2, in which the friction ring 4 and the axially fixed friction rings

7, 10 of the friction wheels 6, 9 have radially flat boundary surfaces. In this embodiment, the friction ring 4 is not axially shifted when changing its eccentricity.

The transmission surfaces 30, 31, 33, 34 are the same as in FIG. 1, as are the displaceable friction rings

8, 11. Pins 26 projecting outward through threaded-section-like slots 27 in the housing 5, which are arranged in the friction ring 8 of the outer friction wheel 6, project outward. For easier operation, handle parts (not shown) or an adjusting ring can also be arranged on the pins 26. This version has a shorter length of the transmission. For reading the set

"gTjRE

OMP A reduction scale can be provided along the adjusting ring.

In the embodiment according to FIG. 5, on the one hand, the radial, eccentric adjustment of the driver 2 is inevitably shown in both directions by its own adjustment device 36 to 40, and on the other hand, the displacement devices 14 to 16 or 26, 27 shown in FIGS. 1 and 2 Return springs 35 replaced. With otherwise the same structure of the gearbox and the same arrangement of the two concentric friction wheels 6, 9 and the radially displaceable friction ring 4, the adjusting device 36 to 40 on the drive shaft side of the housing 5 is for the radial adjustment of the driver 2 of the friction ring 4 arranged. In this embodiment, the housing side wall 51 is provided with a hollow cylindrical extension 45 which is coaxial with the drive shaft 1 and which carries an external thread 40. A ^• adjusting ring 36 is rotatable -on the thread 40 and presses on Anpreßbolzen 37, which penetrate the housing side wall 51 durch¬, to a stationary printing plate 38. The square portion 17 of the drive shaft 1 is opposite the Ausfüh¬ approximately embodiments of FIGS. 1 and 2 extended on both sides over the driver 2, an intermediate plate 39 being rotatably and axially displaceable on the part of the square section 17 facing the housing side wall 51 and a compensating body 42 being rotatably and axially and also radially displaceable thanks to a recess 53. The recess 53 has the same width as the square section 17, but a longer length in comparison. An axial roller bearing 43 is provided between the stationary pressure plate 38 and the intermediate plate 39 rotating with the drive shaft, and a pressure bearing 44 is inserted between the intermediate plate 39 and the compensating body 42. The thrust bearing 44 serves to reduce the friction between the coaxial intermediate plate 39 and the radially displaceable compensating body 42, and can for example consist of balls or rollers held in a cage, not shown, the grooves 52 running in the radial displacement device roll away. The compensating body 42 serves for balancing the driver 2 and is therefore radially displaceable in opposite directions. In order to transfer the pressure exerted by the adjusting device 36 to 40 on the compensating body 42 radially to the driver 2 and the compensating body 42, four articulated levers 41 are provided, each of which forms a parallel gram link. To accommodate the articulated lever 41, the compensating body 42 is provided with two slots which run parallel to the longer side of the recess 53, one slot being provided on each side of the recess 53. Two hinge axes 48 pass through the equalizing body 42 parallel to the shorter side of the recess 53 and form the bearings for the articulated levers 41 arranged in pairs. Two opposing articulated levers 41 are further connected in the middle by a guide pin 47, in a longitudinal slot 46 of the square portion 17 axially slidably sin the other ends of the two-armed articulated levers 41 are in the same way in the driving element 2 stored, ^~ ie of ^"Fig. 6 is seen more clearly. also, the carrier 2 has zw slots 50, which extend parallel and on both sides of the longer side of the recess 18 in the driver 2. The ends of the two-armed articulated lever 41 are mounted in articulated axes 49 which extend parallel to the shorter side of the recess 18 through the driver 2. An axial pressure on the Compensating body 42 moves the guide pin 47 in the longitudinal slot 46. Since the friction rings 30, 31 of the friction ring 4 - on the friction rings 33, 34 of the Rei wheels 6, 9 are present, the free axial displaceability of the disk 3 connected to the friction ring 4 with 2 is not given. The articulated levers 41 are therefore rotated about the guide bolts 47, as a result of which the driver 2 on the one hand and the compensating body 42 on the other hand are displaced radially, but in opposite directions In order to achieve dynamic balancing of the driver 2 and the disk 3 carrying the friction ring 4, a further, equally designed compensating body 42 is preferably arranged on the part of the square section 17 of the drive shaft 1 facing the output shaft 12, which also has a pair of equalizing bodies 42 arranged articulated lever 41 is connected to the Mitneh¬ mer 2, which are also guided on the driver in the slots 50 and are mounted on the hinge axes 49. These articulated levers 41 are also provided with guide bolts 47, which are also axially displaceably guided in the longitudinal slot 46 of the square section 17.

This structural design of the adjusting device is suitable both for the embodiment shown in FIG. 5 with four conical transmission surfaces 30, 31 of the friction ring 4 and for an embodiment corresponding to FIG. 2 with only two such transmission surfaces. In the embodiment shown in FIG. 5, the change in the eccentricity, that is to say the radial displacement of the driver, is caused by "" the "tapered" transmission surfaces - - - - ^• also an axial displacement ^" ds""M'itτrehme_rs"."- When the adjusting device is actuated, the output body - shaft-side compensating body will remain virtually or even completely axially unchangeable and can only be adjusted radially 2, however, the driver 2 remains axially unchanged, and the two compensating bodies 42 are alternately axially displaced when the adjusting device is actuated.

5, a plurality of return springs 35 are prestressed between the housing side wall 29 and the displaceable friction ring 8 of the outer friction wheel 6 in order to reset the two displaceable friction rings 8, 11 of the friction wheels 6, 9.

In the illustration shown in FIG. 7, both the adjustment of the eccentricity of the friction ring 4 and the axial displacement of the friction rings 8 and 11 of the friction wheels take place 6, 9 inevitably in both directions. The displacement device 14 to 16 shown in FIG. 1 is adopted for the axial displacement of the friction rings 8, 11, and the adjustment device 36 to 40 shown in FIG. 5 is provided for the radial adjustment of the driver 2. The cone angles of the transmission surfaces 30, 31, 33 and 34, the angles of the articulated levers 41, and the pitches of the threads 14 and 40 can be matched to one another by experiments in such a way that the two adjusting rings 15 and 36 are coupled to one another and can be operated together. The resetting of the respective parts of the transmission which are not directly pressurized via the adjusting rings 15 or 36 takes place indirectly during the adjustment from the other adjusting ring 36 or 15, so that there is no need for any return spring and the contact pressure is not dependent on the spring.

The adjusting device 36 to 40 of FIG. 5 can be. of course, also combine with the displacement device according to FIG. 2. It is also possible to adjust the pressure plate ^~ 38 ~ in the figure; ~ 5 and- 7 in the manner de -Ver- position of the friction ring - 8- according to Fig. 2 au-szτrbxldenr The - pressure plate 38 can therefore be provided with pins which through thread-like slits in the housing- 5 protrude radially outwards.

The transmission according to the invention has a continuously variable reduction ratio in the case of a coaxial drive and output shaft and a particularly space-saving design, and is also particularly suitable for high torques and uneven loads thanks to the indirect power transmission via the friction ring. The infinite reduction eliminates the need for an additional clutch and provides special protection for the drive.

OMPI

Claims

Patent claims

1. Friction gear for the continuously variable transmission of a rotary movement between a drive shaft and a coaxial output shaft, with a concentric friction wheel fixed to the housing, which has two axially spaced friction rings, each with a transmission surface, at least one of which is conical. and with a friction ring rolling on the transmission surfaces, which is rotatably supported on a driver which rotates and is radially displaceable with the drive shaft, and with an output member between the friction ring and the output shaft, characterized in that a second drive element is used as the output member on the output shaft (12) concentrically arranged friction wheel (9) with two axially adjustable friction rings (10, 11) each with a transmission surface (34) is provided, on which the friction ring (4) along a second tapered Transfer surface (31) rolls, the transfer b areas between the friction ring (4) and the first, outer (6) and the second, inner friction wheel (9) are offset by 180 ° to one another.

2. Friction gear according to claim 1, characterized in that one friction ring (8, 11) of both friction wheels (6, 9) is axially displaceable, the two friction rings (8, 11) having a common displacement device (14-16 or 26, 27th ) and an axial roller bearing (13) is arranged between them.

3. Friction gear according to claim 1 or 2, characterized in that the driver (2) of the friction ring (4) is assigned an axially displaceable adjusting device (36 - 40), the axial displacement of which by means of the articulated lever (41) 2) shifts radially.

4. friction gear according to claim 3, characterized gekennzeich¬ net that the axially movable adjusting device

(36 - 40) at least one compensation body (42) coupled to the articulated levers (41) radially displaces in the opposite direction to the driver (2).

5. Friction gear according to one of claims 1 to 4, characterized in that all transmission surfaces (30, 31, 33, 34) of both friction wheels (6, 9) and the friction ring (4) are conical.

6. Friction gear according to one of claims 1 to 5, da¬ characterized in that the planes of symmetry of the two friction wheels (6, 9) and the friction ring (4) lie one inside the other.