EP0780866B1 - Rotating electric switch for control panel, in particular for car heating, ventilation and/or climatisation devices - Google Patents

Description

The invention relates to electrical switches, and including power switches for control of an electric motor of a motor-fan unit of a heating, ventilation and / or air conditioning system motor vehicle, as described in the preamble to the claim 1 (GB-A-837,433 for example).

Such a switch is generally used to control an electrical device, such as an electric motor of a motor-fan unit. At each position of the body turning point corresponds to a given current intensity intended to power the motor to rotate the blades of the motor-ventilator group according to different speeds.

In some 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 a position intermediate. Such a situation usually causes a durable short circuit which can seriously damage the engine and / or cause circuit lights.

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

The invention provides for this purpose an electric switch rotary as defined in claim 1.

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

Generally, the vertices of the notches are positioned in correspondence of the middle of the space separating the tracks neighboring primaries, which can increase the probability to have a short circuit when the immobilization means are stuck at the top of a notch.

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

Particularly advantageously, the immobilization means include a housing integral with the element rotating and having an open front face, facing the notch device, a spring housed in the housing and supported by a rear end on a rear face of this one, and a ball housed at least partially in the housing, resting on a front end of the spring and diameter significantly less than the distance between the summits of neighboring notches to authorize its immobilization, under stress, between these, when the rotating body is in one of the predefined positions.

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

We thus create an empty area (so-called lost or dead area) with variable geometry, but with constant surface, for the lost stroke, this zone being substantially rectangular when the two flats are parallel, and substantially triangular when the two flats are in abutment one against each other.

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

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

Preferably, the auxiliary immobilization means is an elastic blade installed substantially perpendicularly to the rotating body and close to it, and having in the central part a domed shape appreciably homologous to that of the housing of the body turning.

• 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 does part of a control panel 1 which can, for example, used to control a heating and ventilation device and / or air conditioning of a motor vehicle (not shown on the face).

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

The rotating body 2 is integral, in its upper part a rotary button type control member 3 positioned with free rotation, for example by clipping, in a orifice 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 plate support 7 secured to the wall 4 and produced in a electrically insulated material. The positioning is achieved, for example, by a snap 8 and by a small radial annular extension 9 of the rotating body 2 which strengthens the stabilization of the rotating body.

The switch body is thus perfectly maintained by the guides formed by the orifices in wall 5 and the support plate 7, as well as by the extension of stabilization 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 legs 12 are by example of flexible copper strips.

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

These pads are intended to establish electrical connections between a feed track 13 and one of the tracks primary 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 below pads 10 and 11 and their respective paths.

The feed track 13 forms a strip of general shape circular of which one of the contours occupies more than half of 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 part complementary to the annular area occupied by the runway primary. Each track is independent and electrically isolated from its two neighbors. They can be among two, three, four or more if necessary.

The electric motor of the blower is connected to the different primary tracks 14 via resistors different values allowing, depending on the position of the body turning 2, to force said motor to rotate at a speed chosen by the user.

To ensure that no current is supplied to the electric motor, this which corresponds to the "rest" or "0" position of the switch, it is necessary that the bearing surface of each stud 10 and 11 either on the feed track 13. On the other hand, for that a current supplies the motor, it is necessary that the bearing surface of one of the studs 11, either on the track supply 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 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 includes for this purpose an opening 17 allowing the passage of the intermediate part 15 of the rotating body, which preferably has a shape in this place cylindrical circular with flat 18 (see figure 2). This flat 18 is made 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 body rotating 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 area greater than that occupied by the cross section of the intermediate part 15 of the rotating body 2. The excess area forms a lost or dead area 25 in which the rotating body can rotate freely, relatively disc, over a limited angular portion  (figure 2B).

In order to be able to immobilize the rotating body 2 in its predefined positions, means of immobilization are provided carried by the disc 16 and adapted to cooperate with a circular notch device 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 others on a portion of a circle some distance from the disc 16. The space between neighboring notches delimits an area immobilizer 26 intended to immobilize the means of fixed assets in correspondence with predefined positions of the rotating body.

These immobilization means are preferably carried out under the shape 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 thereof. Her rear face is substantially parallel to the flat 19 of the disc 16 and located in the same "half" of disc as said flat. It has an open front face, facing of the notch device to allow the passage of the ball 24.

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

Of course, the spring and the ball can be free one relative to the other and / or relative to the housing.

The distance between the rear face of the housing 22 from the intersection area 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 areas 26. Consequently, the distance between vertices S of notches is greater than the diameter ball 24.

To further strengthen the immobilization of the ball in immobilization zones 26, the body is provided turning 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 means immobilizer 29 fixed relative to the wall 4.

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

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

Of course, the accommodation can be directly made in the rotating body if it 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. In consequence, when the rotary knob 3 is in the position "0" or "rest", the ball 24 is immobilized in the zone 26-0 and the two studs are on the supply track 13. When the rotary button 3 is in one of the positions "i" (i = 1 to N, N being the maximum number of positions of engine operation), the ball 24 is immobilized in zone 26-i, pad 11 is on the supply track 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 than at a position of the ball in the center of an immobilization zone 26 corresponds to the positioning of the pad 10 on a end zone 31 of a primary track. This zone end may be on one side of a track or on the side opposite. So when the ball 24 is at the top S a notch 20, the pad 10 cannot be between two tracks neighboring primaries, which could cause short circuits.

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

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

FIG. 2A illustrates the switch in its position of "rest". Ball 24 is immobilized in the immobilization zone 26-0 and pad 10 is on the feed track 13. In this position, the lost area 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 move from the position of rest at position "1", he enters the rotary button 3 and starts to rotate it clockwise watch, for example. Due to the presence of the lost area 25, the rotating body 2 begins to rotate freely, thus causing the stud 10 to the right but without drive the disc 16 and therefore the ball 24. When the body turning 2 comes to a stop on the flat 19 of the disc 16 (Figure 2B), said disc begins to be driven. The form of the lost area 25 is then substantially triangular. The bulge 30 of blade 29 is almost out of its housing 28.

The ball 24 then rises towards the top S of the notch 20 located to the right of 26-0 (Figure 2C). Assuming the rotating body would be blocked by friction, the ball 24 secured to disc 16 could not remain audit summit, because under the effect of the drive of the disc it is forced to fall into immobilization zone 26-1 from where it can no longer emerge since the rotation of the rotating body 2 brought about the immobilization of the bulge 30 in housing 28-1 (Figure 2D). The stud 10 is now on runway 14-1 and therefore the button rotary is in position "1".

To move to position "2", or any other position higher, the operation described above is repeated, or well we proceed in the opposite direction to return to the position "0".

By the symmetry of the switch, it is clear that it can work the same way when you impose on your body a rotation greater than 180 °. As a result, pads 10 and 11 are interchangeable.

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

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

Claims (7)

1. Rotary electrical switch for a control panel, in particular for a motor vehicle heating, ventilation or air conditioning device, of the type comprising a rotating body (2) able to be driven in rotation about an axis (XX) under the action of a control device (3), and immobilisation means (22-24) carried by the rotating body (2) and able to cooperate with a serrated device (20) with a circular configuration and carried by a fixed support (21), in order to immobilise the rotating body in predefined positions, the said-immobilisation means form part of an intermediate element (16) rotationally fixed to the rotating body (2) with a limited angular movement defining a dead travel, which makes it possible to decouple the rotating body from the immobilisation means, thus preventing any locking of the immobilisation means in an unstable position at the top (S) of the serration (20), because of friction generated on the rotating body, characterised in that the intermediate element (16) is a disc having a central opening (17) with a chosen shape able to allow the passage of an intermediate part (15) of the rotating body (2) whilst allowing the limited angular movement.
2. Switch according to Claim 1, in which there are provided at least a plurality of identical primary tracks (14), fixed to a support surface (7) perpendicular to the axis of rotation (XX), electrically conductive and evenly spaced apart from each other, and at least one stud (10) fixed to 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 adjacent serrations (20) defines immobilisation areas (26) in correspondence with predefined positions, and in which the primary tracks are positioned with respect to the serrated device so that each immobilisation area is positioned above an end area (31) of a primary track chosen from amongst first and second end areas opposite to each other.
3. Switch according to one of Claims 1 and 2, characterised in that the immobilisation means comprise a casing (22) fixed to the intermediate element (16) and comprising an open front face, opposite the serrated device (20), a spring (23) housed in the casing and bearing through a rear end on a rear face thereof, and a ball (24) at least partially housed in the casing, bearing on a front end of the spring and with a diameter substantially less than the distance separating the tops (S) of the adjacent serrations in order to allow its immobilisation, under stress, between these, when the rotating body is in one of the predefined positions.
4. Switch according to Claim 3, characterised in that the rotating body (2) has, in its intermediate part (15), a circular cylindrical shape with a flat (18), the said flat being produced at a first distance (D1) from the axis of rotation (XX), and in that the opening (17) in the disc (16) has a shape adapted to that of the intermediate part (15) of the rotating body with a flat (19) situated at a second distance (D2) from the axis of rotation (XX) greater than the first distance (D1).
5. Switch according to one of Claims 3 and 4, characterised in that the casing (22) is fixed to the periphery of the disc (16) in a radial position, its rear face being substantially parallel to the flat (19) on the disc (16) and situated in the same disc half as the said flat.
6. Switch according to one of the preceding claims, characterised in that the rotating body (2) comprises, upstream of its intermediate part (15), a circular cylindrical portion (27) comprising, on its periphery, in chosen positions, a plurality of housings (28) intended to cooperate with an auxiliary immobilisation means (29) in order to reinforce the immobilisation of the rotating body when the immobilisation means are in an immobilisation area.
7. Switch according to Claim 6, characterised in that the auxiliary immobilisation means (29) is an elastic blade installed substantially perpendicular to the rotating body and close thereto, and having, in a central part, a bulge (30) with a shape substantially similar to that of the housings (28) in the rotating body.

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