EP0780866A1 - Rotating electric switch for control panel, in particular for car heating, ventilation and/or climatisation devices - Google Patents

Abstract

The electrical switch has a mechanical rotating mechanism. The outer has a fixed set of triangular notches (20) set into the body. The inner is made up of a shaft (16) with an inner half circular element (15) leaving an upper gap (25) in the shaft inner. The shaft has a ball bearing protrusion (22) pushed by a spring (23) into the notch. The shaft construction acts as a dead latch preventing the peak position (5) from being held.

Description

The invention relates to electric switches, and in particular power switches for controlling an electric motor of a motor-fan unit of a heating, ventilation and / or air conditioning device of a motor vehicle.

This invention relates more particularly to a rotary electrical switch, of the type comprising a rotating body capable of being rotated about an axis under the action of a control member as well as immobilization means carried by the rotating body and suitable for cooperating with a notch device, of circular configuration and carried by a fixed support, to immobilize the rotating body in predefined positions.

Such a switch is generally used to control an electrical appliance, such as for example an electric motor of a motor-fan unit. Each position of the rotating body corresponds to a given current intensity intended to supply the motor with a view to rotating the blades of the motor-fan unit at different speeds.

In certain known devices, frictional forces are exerted on the rotating body, which increases its inertia and sometimes causes the immobilization means to stop in the vicinity of the top of a notch, in an intermediate position. Such a situation usually causes a long-lasting short circuit which can seriously damage the engine and / or cause circuit lights.

Consequently, an object of the invention is to provide an electrical switch, for a control panel, which does not does not have the drawbacks of rotary switches of the prior art.

The invention provides for this purpose a rotary electrical switch of the type described above, in which the immobilization means are part of an intermediate element integral in rotation with the rotating body with a limited angular movement defining a lost (or dead) stroke .

Thus, when the rotation of the rotating body is prohibited or severely limited, the intermediate element, which is integral with the immobilization means, can, thanks to the planned lost stroke, be decoupled from the rotating body and therefore rotate freely over a portion angular limited but sufficient to force the immobilization means to be released when said element reaches the lost end of travel. This avoids possible blockage of the immobilization means in an unstable position, for example at the top of a notch.

The switches of the type described further comprise, in known manner, at least a plurality of identical primary tracks, integral with a plane support perpendicular to the axis of rotation, electrically conductive and regularly spaced from each other, and at least one stud secured to the rotating body and intended to contact the primary tracks respectively when the rotating body is in one of the predefined positions. Furthermore, the space between two neighboring notches defines immobilization zones in correspondence with the predefined positions.

Generally, the tops of the notches are positioned corresponding to the middle of the space separating the neighboring primary tracks, which can increase the probability of having a short circuit when the immobilization means are blocked at the top of a notch .

This is why, in the proposed invention, the primary tracks are preferably positioned relative to the notched device so that each immobilization zone is placed in correspondence with an end zone of a primary track chosen from a first and a second end zones opposite to each other.

In a particularly advantageous manner, the immobilization means comprise a housing integral with the rotating element and comprising an open front face, opposite the notched device, a spring housed in the housing and bearing by a rear end on one face rear of the latter, and a ball housed at least partially in the housing, resting on a front end of the spring and of diameter substantially less than the distance separating the vertices from neighboring notches to allow it to be immobilized, under stress, between those here, when the rotating body is in one of the predefined positions.

In a preferred embodiment, the intermediate element is a disc which has a central opening of selected shape and suitable for allowing the passage of an intermediate part of the rotating body while allowing limited angular movement.

Preferably, the rotating body has in its intermediate part a circular cylindrical shape with a flat, said flat being made at a first distance from the axis of rotation, and the opening of the disc is of a shape adapted to that of the intermediate part of the body. turning with a flat located at a second distance from the axis of rotation, greater than the first distance.

An empty area (so-called lost or dead area) is thus produced with variable geometry, but with a constant surface, for the lost stroke, this area being substantially rectangular when the two flats are parallel, and substantially triangular when the two flats are in abutment l one against the other.

According to yet another characteristic of the invention, the rotating body comprises, upstream from its intermediate part, a circular cylindrical portion comprising on its periphery, in selected positions, a plurality of housings intended to cooperate with an auxiliary immobilization means to reinforce immobilization of the rotating body when the immobilization means are in an immobilization zone.

This arrangement notably reinforces the immobilization of the body rotating in the predefined positions.

Preferably, the auxiliary immobilization means is an elastic blade installed substantially perpendicular to and close to the rotating body, and having in a central portion a bulge of shape substantially homologous to that of the housings of the rotating body.

• la figure 1 est un schéma illustrant un commutateur selon un mode de réalisation préférentiel de l'invention, dans une vue en coupe transversale;
• les figures 2A à 2D sont des schémas illustrant les positions relatives respectives de certains éléments principaux du commutateur de la figure 1, dans quatre positions différentes du corps tournant.

In the description which follows, given by way of example, reference is made to the appended drawings, in which:

• Figure 1 is a diagram illustrating a switch according to a preferred embodiment of the invention, in a cross-sectional view;
• FIGS. 2A to 2D are diagrams illustrating the respective relative positions of certain main elements of the switch of FIG. 1, in four different positions of the rotating body.

The electrical switch shown in Figure 1 is part of a control panel 1 which can, for example, be used to control a heating, ventilation and / or air conditioning device of a motor vehicle (not shown in the figure).

This switch comprises a rotating body 2 suitable for being driven in rotation about an axis XX by a user wishing to obtain a particular adjustment of an element of the device. In the following description, it will be considered that the element in question is the electric motor of the blower of a motor-fan unit. But that could be another electrically operated element.

The rotating body 2 is integral, in its upper part with a control member 3 of the rotary button type positioned with free rotation, for example by clipping, in an orifice provided in the wall 4 of the control panel 1. It is intended to take a plurality of predefined positions corresponding to markings of type "0", "1", ..., "N", on the upper face 5 of the wall 4.

The lower end 6 of the rotating body 2 is positioned with free rotation in an orifice formed in a support plate 7 secured to the wall 4 and made of an electrically insulated material. The positioning is carried out, for example, by a clip 8 and by a small annular radial extension 9 of the rotating body 2 which reinforces the stabilization of the rotating body.

The body of the switch is thus perfectly maintained by the guides formed by the orifices in the wall 5 and the support plate 7, as well as by the stabilization extension 9.

The lower part of the body supports, above the support plate 7, two radial lugs 12 electrically connected to each other, preferably diametrically opposite, and at the ends of which are fixed by crimping, respectively, at least one stud 10 or 11, electrically conductive. The radial lugs 12 are for example flexible copper strips.

Of course, the pads can be made by local conformation of the legs 12. But they can also be screwed or welded or even brazed. Likewise, stud supports (radial lugs 12) can take many other forms.

These pads are intended to establish electrical connections between a supply track 13 and one of the primary tracks 14 of a plurality of primary tracks. These tracks 13 and 14 are carried by the upper face of the support plate 7. They are electrically conductive, substantially coplanar and positioned in an arc of a circle below the pads 10 and 11 and their respective paths.

The feed track 13 forms a band of generally circular shape, one of the contours of which occupies more than half the circumference of the annular zone. It is connected to a current or voltage generator (not shown in the figure).

The primary tracks 14 are arranged on the complementary part of the annular zone occupied by the primary track. Each track is independent and electrically isolated from its two neighbors. They can be two, three, four or more if necessary.

The electric motor of the blower is connected to the different primary tracks 14 by means of resistors of different values making it possible, depending on the position of the rotating body 2, to force said motor to rotate at a speed chosen by the user.

So that no current is supplied to the electric motor, which corresponds to the "rest" or "0" position of the switch, it is necessary that the bearing surface of each pad 10 and 11 be on the supply track 13. On the other hand, for a current to supply the motor, it is necessary that the bearing surface of one of the pads 11 is on the supply track 13 and that the bearing surface of the other pad 10 or on one of the primary tracks 14.

In order to reduce the influence of friction due to the mode of positioning of the rotating body 2 and the rotary button 3, the invention provides a disc 16 mounted for free rotation around the intermediate part 15 of the rotating body. This disc comprises for this purpose an opening 17 allowing the passage of the intermediate part 15 of the rotating body, which preferably has in this location a circular cylindrical shape with a flat 18 (see Figure 2). This flat 18 is produced at a first distance D1 from the axis of rotation XX.

The opening 17 of the disc 16 is of a shape adapted to that of the intermediate part 15 of the rotating body with a flat 19 located at a second distance D2 from the axis of rotation XX. D2 being larger than D1, the opening 17 has a surface greater than that occupied by the cross section of the intermediate part 15 of the rotating body 2. The excess surface forms a lost or dead area 25 in which the rotating body can rotate freely, relative to the disc, over a limited angular portion θ (Figure 2B).

In order to be able to immobilize the rotating body 2 in its predefined positions, immobilization means are provided carried by the disc 16 and adapted to cooperate with a device with circular notches 20 carried by a support 21 fixed relative to the wall 4.

The notch device comprises a plurality of notches or teeth 20 (or bulges) installed one next to the other on a portion of a circle at some distance from the disc 16. The space between neighboring notches delimits an immobilization zone 26 intended immobilizing the immobilizing means in correspondence with the predefined positions of the rotating body.

These immobilization means are preferably produced in the form of a housing 22 housing a spring 23 and a ball 24.

The housing 22 is fixed in a radial position on the periphery of the disc 16, for example in an opening of the latter. Its rear face is substantially parallel to the flat 19 of the disc 16 and located in the same "half" of the disc as said flat. It has an open front face, facing the notched device to allow the passage of the ball 24.

The ball is preferably secured to a front end of the spring 23, which is preferably fixed to the rear face of the housing 22 by its rear end.

Of course, the spring and the ball may be free from each other and / or from the housing.

The distance separating the rear face of the housing 22 from the intersection zone of neighboring notches is less than the empty distance of the spring added to the diameter of the ball, so that the ball is applied under stress against the notches 20. Furthermore , the diameter of the ball 24 and the space between vertices S of neighboring notches are chosen so that the ball is firmly immobilized between these notches in the immobilization zones 26. Consequently, the distance between vertices S of notches is greater to the diameter of the ball 24.

In order to further reinforce the immobilization of the ball in the immobilization zones 26, there is provided on the rotating body 2, upstream of the intermediate part 15, a radial extension in the form of a circular plate 27 and comprising on its periphery, in selected positions, a plurality of housings 28 intended to cooperate with an auxiliary immobilization means 29 fixed relative to the wall 4.

Preferably, the auxiliary immobilization means is an elastic blade 29 installed in a plane perpendicular to the rotating body and close to the latter. This blade 29 has, in a central part, a bulge 30 of shape substantially homologous to that of the housings 28.

The respective positions of the blade 29 and of the housings 28 are chosen so that in each predefined position of the rotating body 2 corresponding to an immobilization zone 26 is associated a housing 28 which cooperates with the bulge 30 of the blade 29.

Of course, the housings can be made directly in the rotating body if the latter has a circular cylindrical portion.

Each predefined position of the rotating body is associated with a positioning of the pads 10 and 11, and only one. Consequently, when the rotary button 3 is in the "0" or "rest" position, the ball 24 is immobilized in the zone 26-0 and the two studs are on the feed track 13. When the rotary button 3 is in one of the positions "i" (i = 1 to N, N being the maximum number of engine operating positions), the ball 24 is immobilized in the zone 26-i, the stud 11 is on the runway power supply and the pad 10 is on the primary track 14-i.

In order to avoid stopping the ball 24 at the top S of a notch 20, and this despite the improvements described above, the tracks are preferably placed so that at a position of the ball in the center d 'an immobilization zone 26 corresponds to the positioning of the pad 10 on an end zone 31 of a primary track. This end zone can be on one side of a track or on the opposite side. Thus, when the ball 24 is at the top S of a notch 20, the stud 10 cannot be between two neighboring primary tracks, which could cause short circuits.

It is clear that this arrangement of tracks is not compulsory. It represents only additional security.

The operation of such a switch will now be described with reference to FIGS. 2A to 2D, on which are shown, firstly, in the upper part, the positioning of the pad 10 relative to the tracks 13 and 14-1, d a second part, in the central part, a transverse section along the axis IIa-IIa of FIG. 1, of the intermediate part 15 of the rotating body 2, and a third part, in the lower part, a transverse section along the axis IIb-IIb of FIG. 1, of the circular plate 27.

Figure 2A illustrates the switch in its "rest" position. The ball 24 is immobilized in the immobilization zone 26-0 and the stud 10 is on the supply track 13. In this position, the lost zone 25 is substantially rectangular. The bulge 30 of the blade 29 is housed in the housing 28-0 of the plate 27.

When the user wishes to pass from the rest position to position "1", he grasps the rotary button 3 and begins to rotate it clockwise, for example. Due to the presence of the lost zone 25, the rotating body 2 begins to rotate freely, thus causing the stud 10 to the right but without driving the disc 16 and therefore the ball 24. When the rotating body 2 comes into abutment on the flat 19 of the disc 16 (FIG. 2B), the said disc begins to be driven. The shape of the lost area 25 is then substantially triangular. The bulge 30 of the blade 29 is almost out of its housing 28.

The ball 24 then rises in the direction of the apex S of the notch 20 situated to the right of 26-0 (FIG. 2C). In the event that the rotating body is blocked by friction, the ball 24 secured to the disc 16 could not remain at said top, because under the effect of the drive of the disc it is forced to fall into the immobilization zone 26-1 from which it can no longer emerge since the rotation of the rotating body 2 caused the doming to immobilize 30 in housing 28-1 (Figure 2D). The pad 10 is now on track 14-1 and therefore the rotary button is in the "1" position.

To move to position "2", or to any other upper position, the operation described above is repeated, or else proceed in the reverse direction to return to position "0".

By the symmetry of the switch, it is clear that it can operate in the same way when its body is forced to rotate more than 180 °. Consequently, the pads 10 and 11 are interchangeable.

Furthermore, the invention is not limited to the embodiment described above, but it embraces all the variants that a person skilled in the art may develop within the scope of the claims below.

Thus, the respective shapes of the opening of the disc and of the intermediate part of the rotating body could be completely different from those described, provided that they define a limited lost stroke.

Claims (8)

Rotary electrical switch for a control panel, in particular for a motor vehicle heating, ventilation and / or air conditioning device, of the type comprising a rotating body (2) suitable for being rotated about an axis (XX) under the action a control member (3), as well as immobilization means (22-24) carried by the rotating body (2) and adapted to cooperate with a notch device (20), of circular configuration and carried by a fixed support (21), for immobilizing the rotating body in predefined positions, characterized in that the immobilization means are part of an intermediate element (16) integral in rotation with the rotating body (2) with a limited angular movement defining a lost stroke, which makes it possible to decouple the rotating body from the immobilization means, thus avoiding possible blocking of the immobilization means in an unstable position at the top (S) of a notch (20), due to a rubbing t generated on the rotating body. Switch according to claim 1, in which at least a plurality of identical primary tracks (14) are provided, secured to a plane support (7) perpendicular to the axis of rotation (XX), electrically conductive and regularly spaced apart from one another. others, and at least one stud (10) integral with the rotating body and intended to contact the primary tracks respectively when the rotating body is in one of the predefined positions, and in which the space between two neighboring notches (20) defines immobilization zones (26) in correspondence with the predefined positions, characterized in that the primary tracks are positioned relative to the notched device so that each immobilization zone is placed above an end zone ( 31) of a primary track chosen from first and second end zones opposite one another. Switch according to one of claims 1 and 2, characterized in that the immobilization means comprise a housing (22) integral with the intermediate element (16) and comprising an open front face, facing the notch device (20 ), a spring (23) housed in the housing and supported by a rear end on a rear face thereof, and a ball (24) housed at least partially in the housing, supported on a front end of the spring and diameter substantially less than the distance separating the vertices (S) from neighboring notches to allow its immobilization, under stress, between them, when the rotating body is in one of the predefined positions. Switch according to one of claims 1 to 3, characterized in that the intermediate element (16) is a disc having a central opening (17) of a chosen shape suitable for allowing the passage of an intermediate part (15) of the body turning (2) while allowing limited angular movement. Switch according to claim 4, characterized in that the rotating body (2) has in its intermediate part (15) a circular cylindrical shape with flat (18), said flat being made at a first distance (D1) from the axis of rotation (XX), and in that the opening (17) of the disc (16) is of a shape adapted to that of the intermediate part (15) of the rotating body with a flat (19) located at a second distance (D2) of the axis of rotation (XX) greater than the first distance (D1). Switch according to one of claims 4 and 5, characterized in that the housing (22) is fixed on the periphery of the disc (16) in a radial position, its rear face being substantially parallel to the flat (19) of the disc (16) and located in the same half of the disk as said flat. Switch according to one of the preceding claims, characterized in that the rotating body (2) comprises upstream of its intermediate part (15) a circular cylindrical portion (27) comprising on its periphery, in selected positions, a plurality of housings (28) intended to cooperate with an auxiliary immobilization means (29) to reinforce the immobilization of the rotating body when the immobilization means are in an immobilization zone (26). Switch according to claim 7, characterized in that the auxiliary immobilization means (29) is an elastic blade installed substantially perpendicular to and close to the rotating body, and having in a central part a bulge (30) of form substantially homologous to that of the housings (28) of the rotating body.

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