FR2926665A1 - Electromechanical switching relay useful in casing for controlling the heating of electric circuit, comprises armature carrying magnetic circuit excited by bobbin, movable plate supplied on armature, and flexible shock absorber element - Google Patents

Abstract

The electromechanical switching relay (1) comprises an armature (2) carrying a magnetic circuit (3) excited by a bobbin (4), a movable plate (5) supplied on the armature and induced by displacing a part by magnetic attraction and other part by a helicoidal spring mounted between the movable plate and armature, and a flexible shock absorber element axially connected between the armature and a coil of the spring. The helicoidal spring comprises a loop of fixed end engaged around a fixed spur transverse to the armature. The shock absorber element is a bushing engaged around the fixed spur. The electromechanical switching relay (1) comprises an armature (2) carrying a magnetic circuit (3) excited by a bobbin (4), a movable plate (5) supplied on the armature and induced by displacing a part by magnetic attraction and other part by a helicoidal spring mounted between the movable plate and armature, and a flexible shock absorber element axially connected between the armature and a coil of the spring. The helicoidal spring comprises a loop of fixed end engaged around a fixed spur transverse to the armature. The shock absorber element is a bushing engaged around the fixed spur. The bushing comprises a first radial face in axial support on the first coil of the spring, and a second lateral face in lateral support against the end loop of the spring. An independent claim is included for a casing for controlling the heating of an electrical component.

Description

The present invention relates to electromechanical relay control boxes for controlling the power transmitted to electrical components.

The invention relates more particularly, but not exclusively, to such electromechanical relay control boxes for controlling the supply of power resistors of an additional heater in a motor vehicle. In certain applications, particularly in the power supply control of the power resistors of an additional vehicle heater, an electromechanical relay control unit is used, the power circuit of the relay or relays being electrically connected between the power resistors of the additional heating and the positive terminal of the general power supply of the vehicle. Such a housing is placed generally just behind the dashboard, behind the passenger compartment of the vehicle. The problem is that the electromechanical relays periodically switch the electric power on the resistors of the additional heating, to regulate the heating of the passenger compartment. Whenever a relay switches, either to establish the power supply or to interrupt it, it produces mechanical vibrations that can be transmitted to the surrounding elements, either through the housing itself or via power connection means to the resistors of the additional heater or to the source of electrical power. These transmitted vibrations generate a noise perceptible by the user, noise that the user finds unpleasant or disturbing and should be eliminated. Associated with such a housing, there are generally connectors, for making plug-in connections, easily put in place or removed by simple plugging, for the connection on the one hand to the vehicle's electrical power source, and secondly to the external means of controlling the heating. In these cases, there are generally fuses capable of interrupting the power supply in case of overload or short circuit in the auxiliary heating system. These connectors and fuses are also capable of transmitting vibrations and noises. The source of noise resides in the structure itself of the electromechanical relays used, which comprise a movable plate capable of producing an impact vibration when it comes to the end of the switching stroke, and which comprise a helical spring of recall likely to vibrate after such a shock.

In particular, when switching the relay, the movement of the

moving plate is relatively fast and applies to the helical coil spring. The turns of the helical return spring vibrate at a resonance frequency specific to the spring. The vibration is essentially a longitudinal vibratory movement of the turns relative to each other, but may also have a transverse vibration component, and a vibration of the wire

spring itself. These vibrations continue for one to two seconds, and are audible. It is an acute resonance, producing a too high sound level and an unpleasant sound quality.

The problem proposed by the present invention is to devise means for substantially reducing the presence of vibrations in the

electromechanical relays themselves which are used in such a housing.

The invention simultaneously aims to design such means which are particularly simple, reliable and inexpensive, and which can be adapted to existing relays without substantially changing the structure and operation. These means are thus compatible with the requirements of

cost reduction in certain applications such as application to motor vehicles.

The invention also provides for the application of such means to the relays inserted in the power control boxes of an additional heater in a motor vehicle, thus enabling the reduction of sound vibrations.

generated and transmitted by such a housing.

To achieve these and other objects, the invention provides an electromechanical switching relay for an electric circuit comprising a frame carrying a magnetic circuit excited by a coil, and comprising a movable plate hinged to the armature and biased in displacement. a part by

the magnetic attraction produced by the magnetic circuit and secondly by a helical return spring mounted between the movable plate and the armature, the relay comprising at least one damping element of flexible material engaged between the armature and at least one turn of the helical coil spring.

The damping element opposes the maintenance of the vibrations occurring in the return coil spring when switching the relay, both on opening and on closing. 524IFDFP.doc By the presence of a damping element of flexible material, the vibrations of the return coil spring are more quickly damped, and the generation of sound thus occurs for a greatly reduced duration. In practice, the duration of the sound emitted is reduced to a fraction of a second, which makes it much less noticeable and less unpleasant. According to an advantageous embodiment, the damping element of flexible material is engaged axially between the armature of the relay and an end turn of the return coil spring. The axial support is effective for the reduction of vibrations, the damping exerted on the end turn also having an effect on the movement of the intermediate turns of the return coil spring. Simultaneously, the axial support does not cause any friction movement between the damping element of elastomeric material and the end turn of the return coil spring, which avoids the progressive wear of the damping element and the progressive reduction of its efficiency. Also, the axial support does not affect the switching speed of the relay. Preferably, the return coil spring comprises a fixed end loop engaged around a transverse fixed lug of the armature, and the damping element of flexible material is a sleeve engaged around said transverse fixed lug of the armature.

In this way, the damping element has a particularly simple structure, the fixing is ensured by simple engagement on the transverse fixed lug of the armature that exists on the relays and which serves to fix the coil spring return. Generally, no modification is necessary to be able to engage the sleeve around the transverse fixed lug of the frame. In practice, the sleeve may comprise a first radial face bearing axially on the first turn of the return coil spring. The support of the damping element of flexible material is thus carried out on a turn of the return coil spring.

According to a preferred embodiment, the sleeve may comprise a lateral face in lateral support against the fixed end loop of the return coil spring. In this way, the damping element of flexible material ensures both the reduction of the longitudinal vibrations of the return coil spring, and also the reduction of the transverse vibrations of said spring.

According to another aspect, the invention provides for the application of such an electromechanical relay in an electric heater control box for a vehicle. The housing then contains at least one relay, usually several electromechanical relays.

According to an advantageous embodiment:

said at least one electromechanical relay is mounted on a relay support plate held on a caseback with the interposition of vibration damping pads,

the power input terminals and the power output connection tabs are held on the housing bottom, away from the relay support plate,

- The case bottom is shaped in a bowl with a peripheral lift defining an interior bowl space,

the relay support plate is disposed in a generally parallel orientation at the bottom of the housing and engaged in the interior space of the bowl,

- flexible conductors provide the electrical connection between the relays

electromechanical devices and the input and output connection means,

a flexible polymerized paste fills the volume between the relay support plate and the housing base.

It can be seen that the presence of the flexible polymerized paste, which fills the volume between the relay support plate and the housing base, makes it possible to obtain a very substantial reduction in the transmission of vibrations.

Tests carried out on the same control boxes with and without flexible polymerized paste showed a reduction of transmission of the vibrations of the order of 7 decibels.

These means are particularly simple, reliable and inexpensive, and are compatible with cost reduction requirements in certain applications such as application to motor vehicles.

These means are also compatible with component assembly operations by wave soldering of the pins of the components on a printed circuit.

Other objects, features and advantages of the present invention will become apparent from the following description of particular embodiments, with reference to the accompanying figures, in which:

FIG. 1 is a perspective view of an electromechanical switching relay provided with a damping element according to an embodiment of the present invention;

- Figure 2 is a side view of the relay of Figure 1, showing the damper element engaged between the armature and the return coil spring; Fig. 3 is a detail view of the damping element of Fig. 1;

FIG. 4 is a general perspective view of a control box according to an embodiment of the present invention, in partial section;

Figure 5 is a general perspective view of the control box of Figure 4 as viewed from the opposite side;

Figure 6 is a cross-section of the control box of Figure 1; FIG. 7 is an electrical block diagram of the control box of FIG. 4; and

Fig. 8 is a front view illustrating a fusible power output connection tab structure according to one embodiment of the present invention.

In the embodiment illustrated in FIGS. 1 and 2, an electromechanical switching relay 1 for an electric circuit comprises an armature 2 carrying a magnetic circuit 3 excited by a coil 4. A movable plate 5 is

articulated on the frame 2 according to a joint 7, and carries a movable contact 6 adapted to cooperate with a fixed contact 6a to establish or interrupt the electrical power conduction of the relay 1.

Opposite the articulation 7, the movable plate 5 is extended by a movable pin 9. A helical return spring 8, in this case a tension spring,

is engaged between the movable pin 9 of the movable plate 5 and a fixed pin 10 of the frame 2. Thus, the return coil spring 8 tends to pivot the movable plate 5 so as to move away from one of the other the movable contact 6 and the fixed contact 6a. Conversely, the supply of the coil 4 generates in the magnetic circuit 3 a magnetic field which attracts the movable plate 5 and tends to bring one to the other

the movable contact 6 and the fixed contact 6a to put them in abutment on one another and thus ensure the passage of the electric power in the relay 1.

The helical return spring 8 comprises turns such as the end turn 8a, and comprises two end loops, namely a fixed end loop 8b and a movable end loop 8c.

The fixed end loop 8b is engaged around the fixed pin 10, while the mobile end loop 8c is engaged around the movable pin 9.

As already shown in Figures 1 and 2, a damping element 11 of flexible material is engaged between the armature 2 and the end turn 8a of the coil spring 8. In practice, the damping element

11 is engaged between the fixed pin 10 and the end turn 8a.

In the embodiment illustrated in Figures 1 to 3, the damping element 11 has a generally ring or sleeve shape, and is engaged around the transverse fixed pin 10 of the armature 2. In FIG. in practice, on the fixed lug 10, the fixed end loop 8b of the helical return spring 8 is first engaged, then the sleeve 11. The sleeve 11 has, in this example, a rectangular cross section with two faces main lateral generally flat and four radial faces generally flat. The sleeve 11 bears axially on the first turn 8a of the helical return spring 8 by a first radial face 11a. Simultaneously, the sleeve 11 has a lateral face 11b (FIG. 2) which bears laterally against the fixed end loop 8b of the helical spring of the return 8. Thus, the possible vibrations of the end turn 8a in the longitudinal direction of the helical return spring 8 are strongly damped by the sleeve 11 which remains in axial bearing by its radial face 11a against the end turn 8a. The axial damping exerted against the end turn 8a has a damping effect also on the vibration of the other turns of the helical return spring 8. The transverse or radial vibrations of the helical return spring 8 are damped by the sleeve 11 which remains in lateral support by its lateral face 11b against the fixed end loop 8b of the helical return spring 8. The adaptation of the sleeve 11 to the fixed pin 10 does not require modification of the relay 1 itself , and does not affect the operation of the relay. It is possible to give the passage 11c (FIG. 3) of the sleeve 11 a shape capable of ensuring a force retention of the sleeve 11 on the fixed lug 10. The sleeve 11 or damping element of flexible material may consist of an elastomeric material with good damping properties, for example NBR type synthetic rubber (copolymer of acrylonitrile and butadiene). The general structure of an electric heating control box 20 as shown in FIGS. 4 to 6 is now considered. For application to the control of the auxiliary heating of a motor vehicle, it is generally necessary to to control several distinct electrical resistances, making it possible to deliver several different thermal powers. For this, a housing according to the invention may comprise a plurality of electromechanical relays, a plurality of fuses each connected in series with one of the relays, and a plurality of output connection means. In the illustrated embodiment, the control box 20 comprises a housing bottom 21 which defines an inner housing which can be closed by an attached cover not shown in the figures. 411 - 'DEP.doc 7 In the housing of the housing 20 are placed three electromechanical relays 1, 1a and 1b, a power input connector 22 for connection to an external power supply, a control connector 28, three fuses respectively 31, 31a and 31b, and output connection tabs of

23. Among the power output connection tabs 23, there are first power output connection tabs 23a, 123a, 223a, and second power output connection tabs 23b, 123b, 223b.

The power output connection tabs 23, in the mode of

illustrated embodiment, protrude from the bottom face of the housing bottom 21, while the control connector 28 is accessible from above, and the power input connector 22 is accessible from the rear face of the control box 20.

The three electromechanical relays 1, 1 a and 1 b are mounted on a

relay support plate 24 which is itself held on the caseback 21 with the interposition of three anti-vibration damping pads: in FIG. 4, two damping pads 25 and 26 are distinguished, whereas in FIG. rear shock absorber stud 27.

In practice, each of the damping pads such as the stud 25 comprises

a toroidal element 25a of elastomeric material, engaged along its periphery in a housing 25b integral with the housing base 21, and receiving in its central hole an axis 25c which is integral with the relay support plate 24.

In the illustrated embodiment, the relay support plate 24 is associated with a platen cover 24a, which encloses the relays 1, 1a and 1b.

The power input connector 22 includes a first power input terminal 22a and a second power input terminal 22b. The power input connector 22 is secured to the housing bottom 21, and is thus kept away from the relay support plate 24. Similarly, the power output connection tabs 23 are integral with the housing bottom 21, and are required to

the distance from the relay support plate 24.

Flexible conductors provide the electrical connection between the relays 1, 1a and 1b on the one hand and the input connection means 22 (the power input connector 22) and the output connection means 23 (the legs power output connection 23).

In practice, one of the power terminals of the relays 1, 1 a and 1 b is connected to a common relay track itself connected via a flexible braid 29b to the first power input terminal. 22a of the 41FDEP.doc 8 power input connector 22. Thus, the flexible braid 29b is one of the flexible conductors. The other power terminals of the relays 1, 1a and 1b are each connected to one of the power output connection tabs 23 via a flexible printed circuit 29a which is best seen in FIG. 6 in

chopped off.

The flexible conductors 29a and 29b prevent the transmission of vibrations between the relay support plate 24 and the housing base 21, parallel to the action of the damping pads 25, 26 and 27.

The housing bottom 21 is shaped in a bowl, with a rise

21a device that delimits a bowl interior space 21b (Figure 6).

As seen in Figure 6, the relay support plate 24 is disposed in generally parallel orientation to the housing bottom 21, and is engaged in the interior of the bowl 21 b.

A soft polymerized paste (shown in dotted lines) fills the volume

between the relay support plate 24 and the housing bottom 21. This flexible polymerized paste 30 very substantially reduces the transmission of vibrations from the relay support plate 24 to the housing base 21, and prevents sound resonance phenomena of the volume located between the relay support plate 24 and the housing base 21. In addition, the flexible polymerized paste 30 reduces the risks

water infiltration from the power resistors controlled by the control box 20, and thus reduces the risk of short circuit between the components contained in the control box 20 in case of failure of the peripheral sealing means.

Flexible polymerized paste 30 can also be used to improve the evacuation of calories to the outside atmosphere, if a material with good thermal conductivity is chosen.

The flexible polymerized paste 30 may be a silicone gel, obtained by mixing two liquid components which are poured into the interior of the bowl 21b, and which then come into contact with the facing faces simultaneously.

on the other side of the caseback 21 and the relay support plate 24. For example, the reference gel RTV 6166 available from Bayer Silicones can be used.

The fuses 31, 31a and 31b are each connected between a respective tab 23b, 123b or 223b of the power output connection tabs 23.

and a common fuse track 32 itself connected to the second power input terminal 22b of the power input connector 22. Among the power output connection tabs 23, there is a first power output connection tab 23a, which is connected to the first relay 1, and a second power output connection tab 23b which is connected to the fuse 31.

FIG. 7, which illustrates an electrical diagram according to a preferred embodiment of the invention, is now considered.

In this diagram, there is the first power input terminal 22a, the second power input terminal 22b, the first power output connection lug 23a and the second power output connection lug 22a.

power 23b.

There are also three relays 1, 1a and 1b, and three fuses 31, 31a and 31b.

The three relays 1, 1a and 1b have their respective first power circuit terminal connected to the same common relay track 40 which itself

is connected by the flexible braid 29b to the first power input terminal 22a. The respective second power circuit terminals of the relays 1, 1a and 1b are connected, via respective tracks of a flexible printed circuit 29a, to respective first power output connection tabs 23a, 123a and 223a.

The three fuses 31, 31a and 31b have a first terminal connected to a common fuse track 32 itself electrically connected to the second power input terminal 22b. The second terminals of the fuses 31, 31a and 31b are each respectively connected to one of the respective second power output connection tabs 23b, 123b and 223b.

The first electrical circuit comprises means for supplying a first output element between the respective first and second power output connection tabs 23a and 23b from the first and second power input terminals 22a and 22b. . The first power input terminal 22a and the first output connection leg of

power 23a form a first circuit branch 33a. Likewise, the second power input terminal 22b and the second power output connection pad 23b form a second circuit branch 33b. The first relay 1 and the first fuse 31 are traversed by the electric power current flowing in the circuit comprising the first and second circuit branches.

33a and 33b.

As seen in FIG. 7, according to this embodiment of the invention, the electromechanical relay 1 is electrically connected in series in the first circuit branch 33a, between the first input terminal of power 22a and the first power output connection pad 23a. The fuse 31, in turn, is electrically connected in series in the second circuit branch 33b, between the second power input terminal 22b and the second power output connection leg 23b. In this way, the inevitable heating of the fuse 31 is propagated by the solid electrical conductor which connects it to the second power output connection tab 23b. In the case where the control unit is associated with electric heating elements placed in the air conditioning air flow of the vehicle, the second power output lug 23b is subjected to the cooling air circulation which cools it, discharging the heat from the fuse 31. The possible heating of the main circuit of the relay 1 is discharged by the conductors, and is not cumulative with the heating produced by the fuse 31. This significantly reduces the localized heating of the circuit electrical, heating that can be seen in the architectures of known control boxes, in which the fuse is always found in series with the relay in the same circuit branch. Indeed, it occurs then, in the electrical connection between the fuse and the relay, additional heating, which is not removed by the electrical conductors.

The tests have shown that the localized heating of the electric circuit of a value up to more than 40 ° C. is thus reduced on control box structures 20 of the same size, one of which has an electric circuit. conventional fuse in series with the relays in the same branch of circuit, and the other comprises an electric circuit according to the invention, for an electric current of 25 A per lane (ie 75 A in total) and a room temperature at 20 ° C maximum interior temperatures of: - 178 ° C were measured for the conventional circuit case, the hottest point being the conductive track between the fuse and the relay, - 130 ° C for the case according to the invention, the hottest point being the working contact of a relay. The reduction of the heating is all the more necessary in the case where the electrical circuits are placed in a thermally insulating flexible polymerized paste, insofar as the polymerized paste 30, which reduces the phonic transmission, then also reduces venting the calories outwardly by conduction, and accentuates the heating.

It is understood that the cooling of the fuse 31 is even better than the thermal conduction is improved between the fuse 31 and the corresponding power output connection lug 23b. To further improve this cooling effect, it is possible to arrange for the fuse 31 to be in contact with the second power output connection tab 23b. Preferably, as illustrated in FIG. 8, the fuse 31 may consist of an intermediate portion 230b fuse, with reduced cross section, of the second power output connection lug 23b itself, said intermediate section 230b with section reduced reduction connecting two end sections 231 b and 232b which are themselves each mechanically secured to the housing 20. The present invention is not limited to the embodiments that have been explicitly described, but it includes the various variants and generalizations within the scope of the claims below.

Claims (12)

1 - Electromechanical relay (1) for switching electrical circuits, comprising an armature (2) carrying a magnetic circuit (3) excited by a coil (4), and comprising a movable plate (5) hinged to the armature (2) and urged in displacement on the one hand by the magnetic attraction produced by the magnetic circuit (3) and on the other hand by a helical return spring (8) mounted between the movable plate (5) and the armature (2) , characterized in that it comprises at least one damping element (11) of flexible material engaged between the armature (2) and at least one turn (8a) of the helical return spring (8). 2 ù electromechanical relay (1) according to claim 1, characterized in that the damping element (11) of flexible material is engaged axially between the armature (2) and an end turn (8a) of the coil spring return (8). 3 - electromechanical relay (1) according to one of claims 1 or 2, characterized in that the return coil spring (8) comprises a fixed end loop (8b) engaged around a fixed lug (10) transverse the armature (2), and the damping element (11) of flexible material is a sleeve engaged around said fixed lug (10) transverse of the armature (2). 4 ù electromechanical relay (1) according to claim 3, characterized in that the sleeve (11) comprises a first radial face (11 a) bearing axially on the first turn (8a) of the return coil spring (8). 5 ù electromechanical relay (1) according to one of claims 3 or 4, characterized in that the sleeve (11) has a side face (11b) bearing laterally against the fixed end loop (8b) of the coil spring recall (8). Electric heating control unit (20), comprising at least one electromechanical relay (1) according to any one of claims 1 to 5. 7 ù Control box (20) according to claim 6, characterized in that: - the electromechanical relay (1) is mounted on a relay support plate (24) held on a housing bottom (21) with the interposition of damping pads anti-vibration device (25, 26, 27), - said electromechanical relay (1) is connected by flexible conductors (29a, 29b) to input connection means (22) and output connection means (23) . 8 ù Control box (20) according to one of claims 6 or 7, characterized in that: - the housing bottom (21) is shaped in a bowl, with a peripheral lift (21a) defining a internal bowl space (21b), - the relay support plate (24) is arranged in a generally parallel orientation to the housing base (21) and engaged in the internal bowl space (21b), - a flexible polymerized paste ( 30) fills the volume between the relay support plate (24) and the housing base (21). 9 - Control box (20) according to claim 8, characterized in that the flexible polymerized paste (30) is a silicone gel, which comes into contact with the facing faces one of the other of the bottom of the housing ( 21) and the relay support plate (24). Control box (20) according to any one of claims 6 to 9, comprising at least one electromechanical relay (1, 1a, 1b), at least one fuse (31, 31a, 31b), at least a first and a second power input terminals (22a, 22b), at least a first and a second power output connection tabs (23a, 23b), the first power input terminal (22a) and the first leg power output connection terminal (23a) forming a first circuit branch (33a), the second power input terminal (22b) and the second power output terminal (23b) forming a second circuit branch (33b) , the electromechanical relay (1) and the fuse (31) being traversed by the electric power current flowing in the circuit comprising the first and second circuit branches (33a, 33b), characterized in that: - the electromechanical relay (1) is electrically connected in series in the first circuit branch (33 a), between the first power input terminal (22a) and the first power output connection tab (23a), - the fuse (31) is electrically connected in series in the second circuit branch (33b), between the second power input terminal (22b) and the second power output connection tab (23b). 11 ù Control box (20) according to claim 10, characterized in that the fuse (31) is in contact with the second power output connection tab (23b). 12 ù control box (20) according to claim 11, characterized in that the fuse (31) consists of an intermediate section (230b) fusible reduced section of the second power output connection tab (23b) and -Even, said intermediate section (230b) reduced section connecting two sections 5241PDEP.doc end (231b, 232b) which are themselves each mechanically secured to the housing (20).