DE2857334A1 - Variable ratio conical pulley belt transmission - alters axial pressure on pulley discs to maintain selected ratio irrespective of torque - Google Patents

Abstract

The continuously variable ratio transmission comprises a driving and a driven shaft each carrying a fixed and an axially slidable conical pulley disc connected by an endless belt. The drive disc is slidable via a ratio-adjusting member acting on a pressure ring and balls to engage a conical surface. The balls are movable in axial slots and the axial pressure is varied as a function of transmitted torque to maintain the selected ratio independent of load variations. A similar pressure arrangement is provided at the driven disc but the balls are spring-loaded in the radially inward direction.

Description

Regulating pulley gear with a setting wheel

with screw thread The invention relates to a continuously adjustable I <pulley gear according to the generic term of the M-claim.

These well-known bevel gearboxes work according to the current one State of the art very satisfactory. On the other hand, they belong to the non-positive ones Transmission means with the fundamental disadvantage that this one more or less have a large deviation in the set ratio when starting from it burdened differently by a certain translation, d. H. different great achievements through them. This has to be compared to positive working The reason for transmission is that there is slippage between the chain and the pulleys is available. fit this; Slippage is not the slipping of the transmission medium meant, that can occur here with sudden torque surges. Rather is with this Slippage meant that the looping means when passing through the respective Conical pulley pair does not revolve over a constant radius, but this radius changes, depending on whether it occurs from the unloaded side to ije loaded (downforce) or whether it rotates from the loaded side to the unloaded side (drive). This change in radius causes the belt to wander radially during the passage through the pair of conical disks. This slip, explained in this way, is approaching egg falling characteristic, which means that the gearbox at a certain gear ratio setting rrit increasing size of the transmitted torque to lower abortion numbers goes there.

The other, the ratio characteristic (ideal curve: set Ratio constant over the entire permissible load range) influencing variable are the ones that cannot be completely excluded in any gearbox as in technology at all Elasticity of the loaded components, such as the supporting mechanical or hydraulic or mechanical-hydraulic transmission organs, even if one would overdimension these loaded parts completely, resulting in an uneconomical one Transmission would lead, one could not completely rule out these elasticities. These elasticities now lead to a further change in the course of the gear ratio curve. However, this change may be the above in connection with the Supplement, partially cancel or even overcompensate the falling characteristic curve mentioned above, which depends on the gear construction and type. It is above all the last-mentioned overcompensation is always undesirable because then the transmission with increasing load to higher output speeds goes towards what to be driven against Mass causes an increasing overload of the drive and torsional vibrations can lead. It is therefore generally desirable to use the gear ratio curve at to have a course that is at least a little falling. This easily falling However, the characteristic curve does not result automatically with different gear types, Sonfedern ran soot depending on the need for the application of the transmission Select a gearbox that has roughly the same characteristic curve as the user needed.

The object of the invention is therefore to provide the conical pulley gear Modify and / or add to the initially mentioned type so that a desired translation characteristic can be achieved constructively without much closer, which also in particular a possibility should be given to exclude increasing ratio characteristics. Based on the well-known transmission with its structural peculiarity, a basic possibility to be indicated, which with relatively simple means The correction and / or the desired setting of the transmission characteristic curve is permitted. The measures should at most affect the cost of the transmission in have a practically insignificant scope and represent simple designs.

The invention is based on the knowledge that by torque-proportional, that is, load-dependent actuation processes of a very small order of magnitude, i.e. in the range of often only a few 1/110 mm, both due to translation changes Elasticities as well as the slip can influence, so that then in the Sum of the required gear ratio is achieved.

Based on this, the object is achieved according to the invention in the measures according to the characteristics of the claim.

This also provides a torque-dependent pressing device provided on the output side of the otherwise purely mechanical transmission, the However, through very simple measures to a series of correction devices for the Ratio characteristic is converted. The measures according to the invention So it is possible by only a very minor three directly dependent reversal shift the relevant interchangeable disc the deviations from the gain side gear ratio characteristics @@ her ausbere @@@@ tet.

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@@@@@@ vie the elasticizer from gears @@ eden @ eit @ erzi @@@ lich individually the advantage, @etzdere lieder e @@@@@@ rast @@@@@ stage r @ ä @ tf er - @@ @rl. @r @@@@ - @@@@@@@@ ret @ than the @ places and desired translation is subject.

On the other hand, this has the advantage that now for all applications this transmission can also be used.

The invention and its details are based on her illustrated embodiments explained in more detail. In the drawing show: Pig. 1 is a diagram showing the translation body correction according to the invention; Fig. 2 shows a mechanically supported gear with two opposing, firmly supported friction disks and two axially displaceable friction disks with pressure device on the drive side and device according to the invention on the drive side and ig. 3 and 4 enlarged, partially illustrated axial sections according to the cutting lines III-III and IV-IV in Figures 2 and 3, respectively.

Pig. 1 shows a diagram to illustrate the translation correction according to the invention. The horizontal line p shows the target ratio of the (drive. The ratio characteristic A transmission is then made up of the following components: 1. The slip and 2. the resilience of the supporting elements.

The slip always has a lowering effect on the output speed and results in a falling characteristic. This curve is undesirable if it is very pronounced and is due to the elasticities in the support depending on the gearbox construction reinforced. Then there is the characteristic curve a in Fig. 1. Or falling the characteristic curve due to the slip is reduced by the elasticities in the support or even overcompensated, which ultimately leads to a rising I characteristic curve according to b in Fig. 1 leads when the over translation increase due to the compliance is greater than the reduction in gear ratio due to the slippage.

As already mentioned at the beginning, this rising characteristic curve applies to everyone Pall undesirable. Therefore, one strives for an adjustment via the elasticity of the supporting organs in such a way that there is only a slightly falling gear ratio curve, as indicated in Fig. 1 with c. This weakly falling characteristic allows stable operation.

According to FIG. 2, a drive shaft 2 is located in a transmission housing 1 and an output shaft 3 rotatably mounted, which carry conical disks 4, 5 and 6, 7, which are non-rotatable against each other by parallel keys 8, 9. Here are the opposite Conical head washers 5, 7 axially firmly supported to the right against a shaft collar 10, 11, during the rotation transmission between the respective shaft and the conical disk 4 or 6 takes place by pressing devices 12, 13, as described by DE-PS 25 39 094 is known and will therefore not be described in more detail here.

The support rings 14 and 15 are against adjusting disks 16 and 17 via roller bearings supported. The adjusting disks have external teeth 18 and 19, with which a central Pinion 20 meshes, which can be rotated in the housing and actuated by an Iland wheel 21. When the handwheel 21 is turned, the adjusting disks 16 and 17 are opposed rotated, so dat -'.- them through the threads 22 and 23, via which they are rotatably mounted on the housing are, execute opposite travel ranges.

With this gear, the pressing device 12 provides the torque and gear-dependent pressure forces. In contrast, the pressing device 13 in this respect rendered ineffective by one of the spheres contained in it circumferential ring spring 24, which the balls radially inwardly in the grooves 25 of the pressing device urges. The strength of the springs can have a slight effect on the Pressure device 13 are set, which ensures that the slip-related The reduction in gear ratio and the effect of the elasticity of the gear parts are thus compensated be that again the desired gear ratio characteristic, for example the Characteristic curve c according to FIG. 1 results.

Fig. 3 shows an enlarged. partial sectional view according to FIG Line III-III in Fig. 2 and Pig. 4 shows a sectional view according to section line IV-IV in Fig. 3.

As can be seen in particular from FIG. 4, the annular springs 24 into segments 26, for example three on the scope, divided by radial pins 27 in support rings 15 and axial pins 28 in the Stfitzring 15 are supported radially.

Claims (1)

Claim Infinitely adjustable conical pulley gear with two conical disks each arranged on the input and output shaft and between them revolving transmission means, the conical disks each to res at least are indirectly non-rotatably connected to one another and to their shaft, furthermore two opposing cone disks as axially firmly supported disks are designed, while the other two are used to set and change the gear ratio axially displaceable and supported in the axial direction against a translation actuator and the displaceable conical pulley on the drive side via a rotating mechanical Pressure device for torque or torque and gear ratio dependent generation the contact pressure with pairs of inclined surfaces and co-operating WEelzkörper is supported in the form of balls, which in turn axially against the translation actuator is supported via a support ring, the inclined surface pairs as being essentially Grooves extending parallel to the shaft axis are formed, in which the effective Slope slope is changed over the channel length and in which the balls are substantially axially displaceable with the gear ratio, and at least a; 'cr Support surfaces of the support ring or the adjacent conical disk is designed as pointing to the respective channel wedge surface through which the through the incline of the slope exerted on the balls, radial forces in axial support forces are converted, characterized in that aGf the output side also such a pressing device (13) is arranged and there. the balls of this pressing device against a spring (24 ') which is to be loaded radially onto the gear shaft (3) are.