EP0920045A1 - Magnet swtich for a starter with a sealed partition wall - Google Patents

Abstract

The invention relates to a starter contactor (10) in which a fixed magnetic core (24) is arranged and a coil (14) in the center of which a core (16) moves to act on a rod (20), one section of which (28) carries a contact (30) intended to establish contact between two terminals (32, 34), of the type in which the fixed core (24) delimits a chamber (42) and a chamber (40) and of the type in which the fixed core (24) comprises a cavity (44) in which is received a section of the rod (20), characterized in that it comprises a sealing partition (48) comprising a transverse plate (50), in abutment against the front face of the fixed core (24), which is extended by a flange (52) which cooperates sealingly with the cover (36), and comprising a central part (54) whose shape is complementary to that of the cavity central (44) with which it cooperates sealingly. <IMAGE>

Description

The present invention relates to a contactor vehicle internal combustion engine starter automobile.

More particularly, the invention relates to a contactor for a motor vehicle starter of the type comprising a housing in which a core is arranged fixed magnetic and a coil in the center of which a core mobile moves axially to act on a rod mobile control, a rear section of which is guided by axial sliding in an axial hole of the fixed core and one of which front section carries a movable contact intended to establish a electrical contact between two fixed terminals which extend axially through a front cover which is crimped into the housing, of the type in which the fixed core delimits a chamber rear, in which the moving core moves, and a front chamber in which the movable contact is arranged and the terminals, and of the type in which the front face of the fixed core has a cylindrical central cavity into which is received an intermediate section of the control rod comprising an external radial collar on which a spring for retaining the movable contact is in axial support and the rear part is of shape complementary to that of the bottom of the cavity which extends through the rod guide hole.

The role of this contactor is to establish contact between the two fixed terminals via the mobile contact. However, it may happen that this function does not can no longer be achieved.

Indeed, the starter contactor does not have always a good water tightness and, when the vehicle rolls on wet pavement, splashing water can get inside the contactor. Furthermore, being given the position of the starter switch near the engine, the temperature inside the starter is relatively large, generally close to 90 ° C, La combination of heat and humidity in the contactor has several drawbacks.

First of all, due to the heat and humidity, the pieces which are made of copper are covered with a fine black oxide film which has the property of being insulating and which, therefore, prevents electrical contact between different rooms. The starter switch is then unusable.

Humidity also has the effect of oxidizing the other metal parts such as for example springs, washers, magnetic circuits, etc. Salts from oxidation of these parts can hinder and even block displacements of the movable contact and its rod command which can no longer properly ensure its function.

Water penetration into the contactor can take place in different places. The majority of penetrations are made by the crimping area of the front cover to the front end of the switch housing. However others water droplets can also get inside the contactor through the rear chamber of the movable core, in particularly thanks to the play that exists between the mobile core and the internal walls of the contactor. Then the water particles enter the front chamber of the contactor along the control rod by the radial clearance that exists between the control rod command and the fixed core.

To solve the first part of the problems seal, i.e. the seal between the front cover and the contactor housing, it is already known to use a cord seal deposited on the crimping of the cover by the part front of the case, or use a rubber seal placed either between the front cover and the housing, or between the front cover and the fixed core of the contactor.

However, these devices are likely to deteriorate over time and in particular due to differences in coefficient of expansion between materials of different components that can cause faults and deformations creating passages through which water can seep inside the contactor.

To solve the second part of the problem sealing, namely between the two chambers of the contactor, and more particularly to prevent water from entering the contactor chamber, solutions such as a seal O-rings located on the control rod have already been proposed.

But these provisions cause on the one hand braking of the control rod, and therefore impede the movements of the mobile contact, and they also cause degradation of the seal, particles from this wear risking deteriorating the operation of the contactor placing between the fixed terminals and the movable contact, and forming an insulating film preventing electrical contact between the terminals.

To solve these various problems, the invention offers a starter switch in which are arranged a fixed magnetic core and a coil in the center of which a nucleus moves to act on a rod, a section of which carries a contact intended to establish contact between two terminals, of the type in which the fixed core delimits two chambers and of the type in which the fixed core has a cavity in which a section of the rod is received, characterized in that it has a sealing partition between the two chambers with a transverse orientation plate radial, in axial abutment against the front face of the fixed core, which is extended at its periphery by an oriented axial flange forward perpendicular to the cooperating plate sealingly with a rear face of the front cover of the contactor, and comprising a tubular central part which extends axially backwards whose shape is complementary to that of the central cavity of the fixed core with which it cooperates tightly.

In this way, sealing is achieved for both main sources of water penetration into the contactor, and the moving contact chamber is isolated from any humidity ambient.

• la collerette avant de la cloison est montée à force dans un logement complémentaire du capot avant du contacteur pour assurer l'étanchéité radiale extérieure entre la chambre du contact mobile et la chambre du noyau mobile ;
• la longueur axiale de la collerette de la cloison d'étanchéité est supérieure à la profondeur du logement, afin de réaliser l'étanchéité par écrasement du bord avant de la collerette ;
• la partie tubulaire de la cloison d'étanchéité possède une extrémité arrière en forme de tronc de cône, complémentaire de la forme de la cavité centrale du noyau fixe, sur laquelle le collet de la tige de commande est en appui axial pour assurer l'étanchéité radiale intérieure entre la chambre du contact mobile et la chambre du noyau mobile ;
• l'extrémité arrière de la partie tubulaire de la cloison d'étanchéité comporte une lèvre annulaire dont le diamètre interne est inférieur au diamètre externe d'un collet radial de la tige de commande qui prolonge l'extrémité arrière du collet pour réaliser l'étanchéité entre les deux chambres ;
• la cloison d'étanchéité est moulée en matière plastique;
• la cloison d'étanchéité est réalisée dans la même matière plastique que le capot avant du contacteur pour éviter des défauts dus à la dilatation.

According to other characteristics:

• the front flange of the partition is forcibly mounted in a complementary housing of the front cover of the contactor to ensure the external radial seal between the chamber of the movable contact and the chamber of the movable core;
• the axial length of the collar of the sealing partition is greater than the depth of the housing, in order to achieve sealing by crushing the front edge of the collar;
• the tubular part of the sealing partition has a rear end in the form of a truncated cone, complementary to the shape of the central cavity of the fixed core, on which the collar of the control rod is in axial support to ensure sealing inner radial between the movable contact chamber and the movable core chamber;
• the rear end of the tubular part of the sealing partition has an annular lip whose internal diameter is less than the external diameter of a radial collar of the control rod which extends the rear end of the collar to achieve sealing between the two rooms;
• the bulkhead is molded from plastic;
• the sealing partition is made of the same plastic as the front cover of the contactor to avoid faults due to expansion.

• la figure 1 est une vue en coupe longitudinale d'un contacteur de démarreur avec des moyens d'étanchéité conformes aux enseignements de l'invention ;
• la figure 2 est une vue en section longitudinale de la cloison d'étanchéité ;
• la figure 3 est une vue de face de la cloison d'étanchéité selon la flèche F3 de la figure 1; et
• la figure 4 est une vue partielle en section de la partie centrale tubulaire de la cloison, traversée par la tige de commande.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

• Figure 1 is a longitudinal sectional view of a starter switch with sealing means according to the teachings of the invention;
• FIG. 2 is a view in longitudinal section of the sealing partition;
• Figure 3 is a front view of the sealing partition according to arrow F3 of Figure 1; and
• Figure 4 is a partial sectional view of the tubular central part of the partition, crossed by the control rod.

In the following description, similar elements, similar or identical are designated by the same numbers reference.

FIG. 1 represents a starter contactor 10 (not shown) of a vehicle internal combustion engine automobile.

This contactor 10 comprises a metal housing 12 in which coils 14 are arranged. These coils 14 control the axial displacement of a movable core 16 of which one end is connected to a pivoting lever (not shown) which acts on the starter launcher. The other front end 18 of the movable core 16 acts on a control rod 20 by thrust through a hole 22 of a fixed magnetic core 24 in which the rear part of the rod 20 is mounted sliding axially.

The control rod 20 can therefore be pushed axially towards the front by its rear section 26 and it carries, on its opposite front section 28, a movable contact 30, mounted sliding on the control rod 20.

The movable contact 30 is substantially in the form of rectangular plate and it extends transversely to cooperate with two electrical terminals 32 and 34 of the circuit power and make electrical contact between they. The two electrical terminals 32 and 34 are fixed and they are carried by a front cover 36 whose annular edge rear is crimped into a front part 38 of the housing 12 of the contactor 10.

The contactor 10 also includes a return spring 35, arranged inside the front cover 36, substantially between contact terminals 32 and 34. This return spring 35 is used to push back the control rod 20 and therefore the movable contact 30, when the electrical contact between the terminals 32 and 34 must be interrupted, and when the control 20 is no longer pushed forward by the core mobile 16.

The control rod 20 also includes a section intermediate on which an external radial collar is arranged 27. This radial collar 27 has a front radial face 29 on which a retaining spring 31 is supported to urge the movable contact 30 towards the front of the control rod 20. The radial collar 27 also has a frustoconical rear face 33 which is inclined towards the axis of the rod.

The fixed core 24 delimits two chambers: a chamber front 40 in which are arranged the movable contact 30 and the electrical terminals 32 and 34, and a rear chamber 42 in which the movable core 16 moves axially.

The front face of the fixed core 24 has a cavity axial cylindrical unit 44, the bottom of which opens into the hole 22 for passage of the control rod 20. The hole 22 has a diameter smaller than that of the central cavity 44, and the connection between the hole 22 and the cavity 44 is ensured by a frustoconical part 46 of the cavity 44 which is inclined backwards and towards the X-X axis of contactor 10.

In a conventional contactor, the radial collar 27 of the control rod 20 is in rear axial support on the part inclined 46 of the central cavity 44 of the fixed core 24, by its complementary frustoconical part 33. The inclinations of the inclined part 46 and the rear face of the radial collar 27 are substantially the same so that the two elements are in mutual contact over the largest possible area.

In accordance with the teachings of the invention, the contactor 10 has an internal sealing partition 48.

As can be seen more particularly on the Figures 2 and 3, this sealing partition 48 comprises a transverse plate 50 of radial orientation with respect to the axis X-X of contactor 10. The transverse plate 50 is extended at its periphery by an axial flange 52, oriented towards the front perpendicular to the plate 50, and it comprises a tubular central portion 54 which extends axially towards the back. A rear end portion 56 of the central portion tubular 54 is inclined towards the axis, to define a section of general frustoconical shape.

As can be seen in Figure 1, the partition seal 48 is placed in the contactor 10 between the cover front 36 and the fixed core 24. The axial flange 52 of the partition 48 is arranged in a housing 58 on the rear face of the front cover 36 of the switch 10. Once in place, the sealing partition 48 is fixed to the front cover 36 so definitive by bonding, welding or crimping to prevent any intrusion of water into the chamber 40 of the mobile contact and achieve an external radial seal.

The length of the collar 52 makes it possible to increase the contact surface between the flange 52 and the side walls of the housing 58, which further promotes sealing between the chambers 40 and 42 and / or between chamber 40 of the contact mobile 30 and outside of contactor 10.

According to another embodiment, the partition seal 48 can be force fitted into housing 58. In this case, the axial length of the flange 52 can be greater than the depth of the housing 58 of the front cover 36, and the front end 53 of the collar is slightly crushed against the bottom of the housing 58, during the force-fitting of the sealing partition 48, thus effecting the sealing outer radial between the two chambers 40 and 42.

In order to limit the efforts for the crushing of the front end 53 of the flange 52, this front end 53 may have a protruding crush lip, which will crash more easily on the bottom of the housing 58, while ensuring the seal between the two chambers 40 and 42. This crushing lip can also be arranged in the bottom of the housing 58, for sealing between the chambers of the same way, by crushing the lip when setting by force of the sealing partition 48.

As we can see more particularly on the Figure 1, the sealing partition 48 is arranged transversely in the chamber 40 of the movable contact 30, in contact with the front face of the fixed core 24.

The tubular part 54 of the sealing partition 48 is in contact with the walls of the cylindrical cavity 44 of the core fixed 24. In particular, the inclined rear end part 56 of the bulkhead is in contact with the inclined part 46 of the cavity 44 of the fixed core 24 with which it cooperates tightly.

The radial collar 27 of the control rod is therefore in back support, no longer as was known, on the fixed core 24, but on the inclined rear part 56 of the sealing partition 48 by its frustoconical part 33.

The internal radial seal between the chamber 40 of the movable contact 30 and the chamber 42 of the movable core 16 is provided by the inclined rear face 33 of the collar 27 of the rod control which is supported on the end part 56 inclined rear of the partition 48. Indeed, the spring 35 of control rod 20 reminder firmly hold it in the retracted position, and therefore, the radial collar 27 is resting on the partition 48 causing sealing.

According to another embodiment, the rear part 56 has a flexible annular lip, the internal diameter of which is less than the external diameter of a radial collar 60 which extends the radial collar 27 of the control rod 20 towards the back. The internal radial seal is thus improved, in particularly during movements of the control rod 20. When this is brought back to the position of rest by the return spring, the radial collar 60 spreads elastically the flexible annular lip of the partition sealing, preventing any particle of water from entering inside the chamber 40 of the contactor.

The sealing partition 48 is made of material plastic, this material having various advantages such as that a low cost price, a low weight for the partition, and it can undergo minor deformations without gravity and particular allowing a force insertion, the deformation of the material providing sealing.

Advantageously, the sealing partition 48 is made of the same material as the front cover 36, so avoid problems caused by differences in expansion which can take place and which can cause deformations through which water can infiltrate.

Claims (7)

Contactor (10) for a vehicle starter automobile of the type comprising a housing (12) in which are arranged a fixed magnetic core (24) and a coil (14) at the center of which a movable core (16) moves axially to act on a movable control rod (20), one of which rear section is guided in axial sliding in a hole axial (22) of the fixed core (24) and including a front section (28) carries a movable contact (30) for establishing contact electric between two fixed terminals (32, 34) which extend axially through a front cover (36) which is crimped into the housing (12), of the type in which the fixed core (24) defines a rear chamber (42), in which the movable core moves (16), and a front chamber (40) in which the movable contact (30) and terminals (32, 34), and of the type in which the front face of the fixed core (24) has a cylindrical central cavity (44) in which is received an intermediate section of the control rod (20) comprising an outer radial collar (27) on which a spring for maintaining the movable contact is in axial support and the rear part is of complementary shape to that of the bottom of the cavity (44) which extends through the guide hole (22) of the rod (20), characterized in that it comprises a partition sealing (48) between the two chambers (40, 42) comprising a transverse plate (50) with radial orientation, bearing axial against the front face of the fixed core (24), which extends its periphery by an axial flange (52) oriented towards the front perpendicular to the plate (50) which cooperates with sealingly with a rear face of the front cover (36) of the contactor (10), and comprising a tubular central part (54) which extends axially towards the rear, the shape of which is complementary to that of the central cavity (44) of the core fixed (24) with which it cooperates in a sealed manner. Contactor (10) according to claim 1, characterized in that the front flange (52) of the partition (48) is mounted by force in a complementary housing (58) of the front cover (36) of the contactor (10) to ensure the radial seal outside between the chamber (40) of the movable contact (30) and the chamber (42) of the movable core (16). Contactor (10) according to claim 2, characterized in that the axial length of the flange (52) of the partition sealing (48) is greater than the depth of the housing (58), in order to seal by crushing the front edge (53) of the collar (52). Contactor (10) according to any one of Claims 1 to 3, characterized in that the tubular part (54) of the sealing partition (48) has one end rear (56) in the shape of a truncated cone, complementary to the shape of the central cavity (44) of the fixed core (24), on which the collar (27) of the control rod (20) is in axial support to ensure internal radial sealing between the chamber (40) of the movable contact (30) and the chamber (42) of the movable core (16). Contactor (10) according to claim 4, characterized in that the rear end (56) of the tubular part (54) of the sealing partition (48) has an annular lip of which the internal diameter is less than the external diameter of a collar radial (60) of the control rod (20) which extends the rear end of the collar (27) for sealing between the two chambers (40, 42). Contactor (10) according to any one of previous claims, characterized in that the partition seal (48) is molded from plastic. Contactor (10) according to claim 6, characterized in that the sealing partition (48) is made in the same plastic as the front cover (36) of the contactor (10) to avoid defects due to expansion.

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