EP0278199B1

EP0278199B1 - Improvements in vehicle window drive systems

Info

Publication number: EP0278199B1
Application number: EP87500038A
Authority: EP
Inventors: D. Antonio Romero Magarino
Original assignee: Dispositivos de Accesorios de Puertas SA
Current assignee: Dispositivos de Accesorios de Puertas SA
Priority date: 1986-06-19
Filing date: 1987-06-17
Publication date: 1994-09-07
Anticipated expiration: 2007-06-17
Also published as: EP0278199A3; DE3750508T2; DE3750508D1; EP0278199A2

Description

This invention relates to an elastic torque transmitter used in combination with vehicle window drive systems, for example, within this field, it is interesting for the starting or blocking of a determined torque to be carried out progressively so that the transmitter element and motor do not suffer when turning either clockwise or anticlockwise during their operation.
In the conventional mechanisms known for this purpose, spiral compression springs, or elastic items made of natural or synthetic rubber are normally used to regulate the circular damping. With these, the angle in which the damping is carried out is centred on values of little importance, and in which the smoothness required in the starting of the elements is not produced.
A known device of this type is United States Patent A-3,984,998 Rokagos, which provides a spring and a toothed pinion mounted on the general shaft of the assembly.
This patent deals with an elastic torque transmitter that turns in both directions, which has a very smooth starting together with a high torque damping in the presence of any blocking in the transmission system and without any axial effects being produced on the turning shaft. This object is achieved by an elastic torque transmitter according to claim 1
Another aim of the patent is that of providing an extensive range of torques to transmit between high-power transmissions to micromechanisms.
The transmitter is based on a simple mechanism able to transmit a determined torque in terms of the initial tension of a special, spiral spring which is previously calculated in relation to the torque to be developed while in operation, it is also possible for the transmitter to absorb an increase in the said operating torque, due to either brusque starting or an obstacle that means an impediment for the turning of the assembly, becoming an indispensable item as a damping element.
The invention is mainly centred, and it is made up of a crown, for example a coupling flange to the drive unit, a sheave or toothed pulley, a crown wheel or sprocket ... etc., with the hollow interior of this crown wheel having an integral circular ring which juts out into this interior part, this ring being provided with a dragging sector of a variable angular value, which extends a certain amount towards the centre of the crown for patent clarification, the variable angular value of the crown sector will be called (a).
Two shoes in the form of a circular sector are supported by their outer surface in the circular ring of the crown wheel and supported by one of their ends on the sides of the dragging sector. The two shoes do not take up the whole of the circular ring, so that their opposite ends which are not supported on the circular sector, are situated at a certain distance from each other.
A circular spring is housed in the interior of the shoes, with the ends of the projection being lodged in recesses in their interior. The spring has a natural tendency to operate on the shoes, so that the shoes rest on the dragging sector and the other ends of shoes become situated at an angular distance due to the action of the circular spring; a distance that will be called (b).
The above-mentioned crown whell has grooves on both sides of the circular ring and dragging sector, in which two interconnected circular bodies are housed, in such a way that the crown turns freely between the said similar bodies, as the three elements are positioned according to a same, single shaft, so that each one of the circular bodies fits into the corresponding groove of the crown at both sides of the circular ring.
The circular bodies are provided in their turn with grooves carried out in opposite directions, with relation to each other, so that they become face to face when they are housed in the grooves of the crown wheel, forming and internal hollow which holds the circular ring, the circular spring and the two shoes, Both grooves of the cylindrical bodies are also provided with rectangularly-shaped projections whose base is identical to the dragging sector of the crown wheel where the shoes rest.
Apart from this, the two circular bodies are related to each other, as was mentioned earlier. One of the circular bodies has a hollow axial projection in which the circular spring is supported and which culminates in a truncated cone portion that is partially slotted in an axial direction along all its circular contour.
The other cylindrical body extends, also axially, into a neck that receives the projecting part of the other body, with a wall that meets the front of the other body and a circular housing that receives the truncated cone portion of it, so that like this both circular bodies become joined together solidly.
The circular spring that was mentioned earlier can be formed of one or several spirals of steel wire, with its ends directed towards the outer part of the spiral and loops in an axial direction and towards the interior, so that its stress is carried out in the perpendicular turning plane, without any axial stress being established. However, they could also be radially placed towards the exterior.
By the effect of the initial tension of the spring, the shoes and the dragging sector of the crown wheel are intimately joined, and this initial tension is what determines the initial minimum torque to be transmitted, with an angular separation (b) between the ends of the spring.
If we consider the cylindrical bodies to be fixed and we turn the crown wheel in either direction, we submit the two cylindrical bodies to a minimum drag torque which is what corresponds to the one determined by the spring and, therefore, we can move it with this value, without the angle (b) of the spring being altered.
However, if a greater initial torque should be required, for example, in starting, the supplementary energy stored in the spring can be used up to a maximum value in which angle (b) is equal to zero.
In these movements, one of the shoes is blocked by the rectangular projections of the two cylindrical parts, while the other slides along the grooves in them, whether the movement is to the right or to the left.
Identical effects are produced if during the course of any normal turning movement the transmitter meets an obstacle, which might be, for example, an overload at a stroke end, etc.
Obviously, the circular damping is always carried out within the angle (b) of the ends of the spring, and its extent is in terms of the angles (a) covered by the dragging sector of the crown and the angular sector (c) covered by the shoes themselves.
In practice, a certainly wide value can be arranged for angle (b), which represents a very considerable value with respect to presently used mechanisms, in which spiral compression springs or elastic elements of natural or synthetic rubber are used.
On the other hand, in the mechanism that recommends the invention, the sliding friction of the shoes on the grooves or slots means that the transmission of the circular movement is carried out uniformly and therefore without oscillations.
All that has been mentioned up to now, together with other details of the invention, is pointed out in relation with the adjoinging pages of drawings, in which they are represented as follows:

Figure 1 is a base cross section of the torque transmitter of the patent.
Figure 2 is a view from the left of figure 4, in which the line marked as XX corresponds to figure 1.
Figure 3 is a perspective of the transmitter assembly.

As regards figures 1 to 3, the crown wheel (1) can be observed, with, for example, the copling flange for the drive unit, a rim pulley, a toothed crown, etc., which has in its hollow interior a circular nerve or ring (10) which provides a slideway (9), with two grooves (11) and (11') at both sides of the said ring (10).
This ring is interrupted by a dragging sector (3) which extends towards the geometrical centre of the crown wheel (1) with an (a) angle of variable value according to needs, In this sector (3), and specifically at its ends, the two shoes (4) and (4') are supported in the form of a circular segment of angular value (c), which on their insides (13) receive the spring (8), whose ends (16) and (16') are opportunely housed in portions (14) and (15) of the said shoes.
The two ends (16) and (16') of the spring (8) are to be found in an axial direction, as is clear, and this is why they are taken in perfectly in the shoes (4) and (4'). The outer surfaces of the shoes will slide opportunely on the slideway (9) once housed with the spring (8) in their interior, and with the ends (16) and (16') of the spring (8) being separated in an angle (c).
The grooves (11) and (11') of the crown wheel (1) receive the projections (17) and (17') of the two cylindrical bodies (2) and (2'), as is shown in figure 2. The projection (17) of body (2) has in its interior a slot or groove (7), in which is made a rectangularly shaped projection (6) of angular value equal to that of the sector (3) of the crown wheel (1). The projection (17') of part (2') has in its turn the slot or groove (7'), also provided with the projection (6') angularly coincident with the sector (3) of the crown wheel (1).
The two cylindrical bodies (2) and (2') are suitably integrated, thanks to the introduction of the dentated truncated cone projection (5) of the body (2) in the internal housing of body (2'), and of the projections (5) of body (2) over the slots (12) of body (2'), as male and female, as can be observed.
In figure 2 it can be observed how the projecting portion of the crown wheel, defined by the sector (3) and by the slideway (9), closes the gap produced between the two parts (2) and (2') and over the crown wheel (1), in which the crown wheel (1) turns freely between the said cylindrical parts.
The shoes are supported on the sector (3) and on the other projections (6) and (6'), of the same angular value as that of the two cylindrical bodies, by the effect of the initial tension of the spring (8), which determines, as has already been stated, the minimum initial torque to be transmitted, leaving the angle (b) between the ends of the spring as is shown in figure 1 in which the shoes are supported on the dragging sector (1) and on the projections (6) and (6') of the cylindrical parts (2) and (2'), which take in an angle (a).
The extent of the damping will depend on this angular value (a) and on the angular value (c) corresponding to the shoes, values which are open to modification in order to vary the characteristics of the assembly keeping the spring (8), the spring (8) can in turn have its characteristics varied in order to obtain additional modifications in regulation.
It should also be pointed out in figure 2 that the two grooves (7) and (7') of the cylindrical bodies become situated in a symmetrical fashion with respect to the plane XX shown in the said figure.
The two projecting ends (16) and (16') of the spring are housed in two recesses, which are not illustrated, in the positions (14) and (15) respectively of the shoes, in such a way that their fit is perfectly secure.

Claims

Elastic torque transmitter of the type that have a spiral spring (8) and a crown wheel (1), characterized in that the crown wheel (1) is hollow on the inside and has an inner circular ring (10) from which an angular dragging sector (3) stands out, directed towards the centre of the crown wheel, of a variable angular value (a), in that this circular ring has two lateral grooves (11, 11') in which the heads of two hollow cylindrical bodies, male and female (2, 2'), are housed, coaxial with the crown wheel, with the heads of the said bodies having symmetrically opposed grooves (7, 7') over the ring of the crown wheel, from which the rectangular section projections (6, 6') of the same width as the dragging sector (3) of the crown wheel stand out, in that the male cylindrical body (2) has a neck (12) that projects out towards the other body, a neck that finishes in a thick dentated truncated cone (5), which houses itself inside the other neck of the female body (2') coming butt to butt with an internal face in the form of a circular crown and inserted into the circular hollow adjacent to the said face, in such a way that the crown (1), the heads of the male and female cylindrical bodies and the projecting neck of the female cylindrical body form between themselves a closed hollow in which two shoes (4) are situated, in the shape of a circular segment of a certain angular value, which has in its interior a circular spring (8) whose projecting ends are taken in by the two ends of the shoes and distanced from each other at a certain angle (b), while the other ends of the shoes are supported on the dragging sector (3) of the crown wheel and on the rectangular projections of the cylindrical bodies, with the possibility that the said shoes can slide along the grooves of the cylindrical bodies and the circular ring of the crown wheel, and in that the circular ring and the dragging sector of the said crown whell enter and turn freely between the male and female cylindrical bodies, with elastic torque being carried out in rotation, in both turning directions and without axial effects on the turning shaft.
Elastic torque transmitter, according to claim 1, characterized in that the heads of the cylindrical bodies are symmetrical with respect to a plane perpendicular to the shaft of the assembly that passes through the central area of the circular ring (10) of the crown wheel (1).
Elastic torque transmitter, according to claim 1, characterized in that the spring (8), which is preferably made of steel wire, has at least one spiral and its ends are preferably directed towards the outer part of the spiral and loops in an axial direction and towards the interior of the spring itself.
Elastic torque transmitter, according to claims 1 and 3, characterized in that the angular value (b) of separation between the ends of the spring (8) is variable in itself and by altering the angles (a) of the dragging sectors and (c) of the shoes.
Elastic torque transmitter, according to claims 1 and 4, characterized in that the dragging sector (3) of the crown wheel (1) and the rectangular projections (27, 27') of the two cylindrical bodies have a variable angular value (a).
Elastic torque transmitter, according to claims 1 and 4, characterized in that the angular value (c) of each one of the shoes is variable.
Elastic torque transmiter, according to claim 1, characterized in that the elastic torque in rotation, is carried out in both turning directions and without axial effects on the turning shaft.
Elastic torque transmitter, according to claims 1 and 3, characterized in that the free ends of the spring (8) are radially positioned towards the exterior from its centre.