FR2797091A1 - CONTACTOR FOR A MOTOR VEHICLE STARTER COMPRISING ELECTRICAL GROUNDING MEANS IN THE REST POSITION AND STARTER PROVIDED WITH SUCH A CONTACTOR - Google Patents

Abstract

Contactor (10) for a motor vehicle starter, of the type comprising a movable contact (44) capable of being moved in translation, between a rest position in which the contact (44) bears against a fixed conductive element connected to a pole mass (16) of the vehicle, and an active position, of the type in which means are provided which, when the movable contact (44) is in the rest position, make it possible to establish an electrical contact between the supply terminal (30) and the electrical ground via the movable contact (44), characterized in that it comprises a sealing partition (98) which separates two compartments inside a support block (26) , and in that said contact means which electrically connect the movable contact (44) to the pole mass (16), when it is in the rest position, is a metallic connection (118) which passes through the sealing partition ( 98).

Description

"Contactor for a motor vehicle starter comprising means for

  electric grounding in rest position and starter provided with such a contactor "The invention relates to a contactor for a motor vehicle starter comprising means for electrically grounding

  rest position and a starter fitted with such a contactor.

  The invention relates more particularly to a contactor for a motor vehicle starter, of the type comprising a movable contact capable of being moved in translation, by a control rod belonging to control means, between a rest position in which the contact is resting against a fixed conductive element connected to a polar mass of the vehicle and towards which it is biased by elastic return means, and an active position, in which the movable contact establishes the electrical connection between a current input terminal, connected to the positive terminal of the vehicle battery, and a starter motor supply terminal, of the type in which means are provided internal to the contactor which, when the movable contact is in the rest position, make it possible to establish an electrical contact between the supply terminal and the electrical ground of the vehicle by means of the movable contact, and of the type in which el the elastic return means are arranged between the movable contact and a block of

  terminal support made of insulating material.

  It is known to provide for the electrical grounding of the motor supply terminal as soon as the contact established by the contact is interrupted.

mobile.

  Indeed, such an arrangement allows effective braking and

  starter motor rotor speed.

  Thus, the starter motor, which has an inductor winding and an induced winding electrically connected in series, finds itself in an electrical short circuit when the supply terminal is

  vehicle electrical ground.

  The starter motor rotor is then braked by auto-

  induction. To ensure correct operation of this device, it is necessary that the grounding of the power supply terminal is interrupted when the starter motor is operated, otherwise the

cause a short circuit.

  In French patent application No. 95.07046, it is proposed to connect the starter motor supply terminal to the starter ground. This connection is made by the movable contact of the contactor. In the rest position it is connected to the motor supply terminal and it

  is in direct contact with the electrical ground of the contactor.

  Furthermore, the starter contactor does not always have

good water tightness.

  When the vehicle is driven on a wet roadway, splashing water can get inside the switch. In addition, given the position of the starter switch near the engine, the temperature inside the starter is relatively high, generally close to 90 C. The combination of heat and

  humidity in the contactor has several disadvantages.

  The pieces which are made of copper are covered with a thin film of black oxide which has the property of being insulating and which, by

  Therefore, prevents electrical contact between the different parts.

  The starter contactor may then be unusable.

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

function.

  In addition, it is advantageous to use electronic circuits for controlling the supply of the contactor winding. Such electronic circuits make it possible to have perfect control of the displacement of the movable core of the contactor, displacement which has the consequence, on the one hand, of causing the supply of the electric motor to the starter and, on the other hand, of causing the meshing. a starter gear with

  a ring gear of a heat engine of the motor vehicle.

  It is possible to arrange the electronic circuit outside the contactor, but it is preferable to integrate it inside the front cover

  of the contactor so as to reduce the total size thereof.

  Electronic circuits are also very sensitive to dust, humidity, and metallic particles which can create

  electrical connections between the different tracks of the circuit.

  Sealing is then achieved by the polar mass on the one hand, by the contact of its outer circumference with the cylinder block or the terminal support block and, on the other hand, at the level of the annular bore

  allowing the passage of the control rod.

  In some contactors, the electronic card is arranged in a compartment of the cover which is delimited by the polar mass and a watertight partition o which increases the tightness in the

  hood compartment including terminal contact heads.

  The presence of these sealing means and in particular of the sealed compartment makes electrical contact between the

  moving contact and the earth of the contactor.

  The object of the invention is therefore to propose a contactor comprising a sealed compartment in which electronic circuits are placed and a device for grounding the supply terminal. The invention provides a contactor of the type seen above, characterized in that it comprises a sealing partition which separates, in a space delimited inside the support block, a sealed front compartment in which the terminals and the contact plate, and a sealed rear compartment, in which an electronic circuit is arranged, and in that said contact means which electrically connect the movable contact to the pole ground, when it is in the rest position, is a metal connection which passes through the sealing partition. According to other characteristics of the invention - the sealing partition has a transverse wall of radial orientation and an axial barrel which is crossed by the control rod and which comprises a front axial annular section and a rear axial annular section connected by a transverse annular face; - The so-called transverse annular face has an axial hole to allow the passage of the metal connection; the metal connection comprises a rear annular base which is axially crossed by the rear axial annular section and which is interposed axially between said transverse annular face and the pole mass, and comprises a tongue which extends axially forward from the rear annular base through the axial barrel and the front free end of which is in contact with the movable contact when it is in the rest position; - The sealing partition is made by molding in an electrically insulating material, and in that the metal connection is embedded in the sealing partition so that its faces which ensure the electrical contact between the pole ground and the contact mobile are o free from all traces of material that could affect electrical contact; - The transverse annular face comprises a peripheral lip which cooperates with a radial surface before the polar mass; - A seal is placed on the rear radial end of the rear axial annular section so as to seal between a rear section of the control rod and the sealing partition during

movements of the mobile contact.

  The invention also provides a starter comprising a

  contactor in accordance with the teachings of the invention.

  Other characteristics and advantages of the invention will appear

  on reading the following detailed description for understanding

  which should be attached to the accompanying drawings in which: - Figure 1 shows a contactor according to the prior art which is illustrated in axial section; - Figure 2 is a view similar to that of Figure 1 which shows a contactor according to the invention and on which the movable contact in the rest position allows grounding of the power supply terminal of the contactor; - Figure 3 shows an exploded view of the bulkhead and the metal connection; - Figure 4 shows an axial section view of the partition

  waterproof with its embedded metal connection.

  FIG. 1 represents a starter contactor 10 according to the state of the art. It comprises a cylindrical casing 12 in which is mounted an annular winding 14 which, when it is traversed by an excitation current, causes an axial magnetic flux in the contactor, in particular thanks to a polar mass 16. The winding 14 is then

  likely to cause axial displacement of a movable core 18.

  The movable core 18 is thus capable of sliding between a rear rest position in which it projects axially through a first axial end 20 of the contactor 10, and an active front position in which, under the effect of the magnetic field induced by the

  winding 14, it is almost entirely received inside the winding 14.

  A helical compression spring 22 resiliently recalls the

  movable core 18 towards its rest position.

  The casing 12 of the contactor 10 is closed at its second opposite axial end 24 by a block 26 for supporting the terminals 28, 30 provided

  for the electric supply of the starter motor (not shown).

  The support block made of insulating material 26 comprises a cylindrical annular skirt 32 which allows its centering and its fixing to the end 24 of the casing 12 of the contactor 10, and a transverse bottom 34 which

axially closes contactor 10.

  Advantageously, the support 26 is made of plastic.

  Terminals 28, 30 are substantially diametrically opposite

  on the bottom 34, on either side of the axis of symmetry of the contactor 10.

  The terminals 28, 30 each have a contact head 36, 38 arranged inside the contactor 10, against the transverse bottom 34 of the support block 26, and a connection pad 40, 42, partly threaded and which extends axially through the transverse bottom 34 so as to

  lead to the outside of contactor 10.

  The first terminal 28 is provided to be connected to the positive terminal (not shown) of a vehicle storage battery and the second terminal 30 is provided to receive a power cable

  (not shown) of the starter motor.

  The support block 26 is made of insulating material. It is fixed, by

  example by crimping, at the end 24 of the contactor 10.

  A movable contact 44, consisting of a plate, is capable of being moved axially inside the space 45 delimited by the annular wall 32 and the bottom 34 of the support block 26, between a rear rest position in which it bears against the pole ground 16 of the contactor 10 and an active front position in which the movable contact 44 bears simultaneously against the heads 36, 38 of the terminals 28, 30 so as to establish between these two terminals 28, 30 an electrical connection which supplies the starter motor with electric current from the vehicle's storage battery. The axial movement of the movable contact 44 is controlled by a control rod 46, which is guided axially in the polar mass

  16, and whose movements are controlled by the movable core 18.

  In known manner, the movable contact 44 is slidably mounted on

the control rod 46.

  The control rod 46 drives the movable contact 44 from its rest position to its active position by means of a contact spring 48 which bears on one side against a shoulder 50 of the control rod 46 and the other side against the rear transverse face 52 of the movable contact 44. When the contact 44 is in the rest position, the rear transverse face 52 is in axial support towards the rear against the

polar mass 16.

  This constructive arrangement, combined with mounting with radial clearance of movable contact 44 on the control rod 46, allows slight swiveling of the movable contact 44 and thus ensures perfect electrical contact against the heads 36, 38 of the terminals 28, 30, even in the case where these

show uneven wear.

  A return spring 54 allows to bring back the control rod

  46 and the movable contact 44 in the rest position.

  The return spring 54 is supported at the bottom of a cylindrical housing 55 arranged at the center of the transverse bottom 34 of the block 26 and it axially urges a metal washer 56 which is pressed against a second shoulder 58 of the control rod 46 and against the front transverse face 60 of the movable contact which also cooperates with the

terminals 28, 30.

  The metal washer 56 is fixed axially on the control rod 46 against the shoulder 58 by a claw washer 62 which is

  press-fitted onto the axial end 64 of the control rod 46.

  To connect the power supply terminal 38 to the electrical ground of the vehicle via the movable contact 44, a piece of cut and folded sheet metal 66 is provided which has an end 68 interposed between the contact head 38 of the terminal 30 and the transverse bottom 34, which has a connecting strip 70 which extends axially along the internal face 72 of the annular wall 32 of the support block 26, and which has a second end 74 curved radially inwards. When movable contact 44 is in contact with the pole ground 16, the second curved radial end 74 is intended to cooperate

  with the rear transverse face 52.

  A transverse insulating plate 76 made of insulating material makes it possible to avoid any contact between the curved end 74 and the polar mass

1o 16.

  This plate 76 is pierced in its center with a hole 78 for the passage of the control rod 46 and it also includes a bore 80 through which extends axially a protuberance 82 of the polar mass 16 intended to come into contact with the transverse face

rear 52 of movable contact 44.

  The protrusion 82 is located transversely in the same plane as the curved end 74 of the lug 66 so as to allow the movable contact 44 to be, in the rest position, simultaneously bearing against the protrusion 82 of the polar mass 16 and against the curved portion 74 of the tab 66 so as to make the electrical connection between the power supply terminal 30 and the electrical ground of the vehicle.

  FIG. 2 represents a contactor according to the invention.

  As can be seen more particularly in FIG. 2, the movable contact 44 and the contact heads 36 and 38 are received in a front compartment 90 of the support block 26 which is substantially of parallelepiped shape, while a rear compartment 92 of the support block 26, of generally cylindrical shape, allows the support block 26 to be joined

with the casing 12 of the contactor 10.

  In known manner, the contactor 10 comprises a printed circuit board 94 which extends in a transverse plane and which is received inside the rear compartment 92 of the support block 26. The printed circuit board 94 carries an electronic circuit for command of

  the supply of the field winding 14.

  3s The rear compartment 92 is delimited axially inside the support block 26 on the one hand, at the front, by a transverse wall 96 belonging to a sealing partition 98 and, on the other hand, at the rear , by the polar mass 16. The sealing partition 98 is shown in detail

in Figures 3 and 4.

  Advantageously, the sealing partition 98 is produced by molding in plastic material, this material having various advantages such as a low cost price, a low weight for the partition, and it can undergo without gravity small deformations thereby allowing a force insertion. The seal is obtained by the

material deformation.

  Advantageously, the sealing partition 98 is made of the same material as the support block 26, in order to avoid the problems caused by the differences in expansion which may take place and which

  can cause deformation through which water can seep.

  In this way, the front compartment 90 of the support block 26 is delimited axially, at the rear, by the transverse wall 96 of the sealing partition 98 and, at the front, by the bottom 34 through which extend axially outwards, the threaded cylindrical body of each of the

terminals 28, 30.

  Thus, the control rod 46, which connects the movable magnetic core 18 to the movable contact 44, axially passes through the rear compartment 92 of the support block 26, in particular passing through the polar mass

  16 through an axial bore 110 thereof.

  The polar mass 16 is fixed to the cylindrical casing 12 so as to

  prevent water from entering the rear compartment 92.

  The sealing partition 98 comprises a substantially tubular axial barrel 100 which makes it possible to make the rear compartment 92 substantially sealed with respect to the front compartment 90 of the support block 26 and with respect to the central bore of the coil body in which the

mobile magnetic core 18.

  The axial barrel 100 has the form of a stepped cylindrical tube which delimits an internal bore 102 and which consists of a front axial annular section 106 and a rear axial annular section 108. The diameter of the front axial annular section 106 is greater than that of the section

rear axial annular 108.

  The front axial annular section 106 and the rear axial annular section 108 of the barrel 100 are delimited axially and are connected by a transverse annular face 112 turned towards the rear. The rear axial annular section 108 is intended to be received inside the bore 110 of the pole piece 16 with which it cooperates in a sealed manner. As can be seen in FIGS. 2 and 3, the internal bore 102 of the axial shaft 100 opens axially forwards, in the front compartment 90 of the support block 26, and rearwards, in the bore 110 of the polar mass 16, so that the internal bore 102 of the barrel 100 forms an axial passage connecting the internal bore of the coil body to the

o0 front compartment 90.

  In a first embodiment, a metal connection 118 is inserted in the watertight partition 98. The metal connection 118 ensures the electrical contact between the pole ground 16 and the contact

  mobile 44 when it is in the rest position.

  Advantageously, the material of the metal connection 118 is chosen so that it constitutes sufficient electrical resistance to not

  not produce too sudden braking of the starter rotor 10.

  The metal connection 118 consists of a tongue 120 and a rear annular base 122 whose outside diameter is

  less than the outside diameter of the rear axial annular section 108.

  The tongue 120 extends, from the rear annular base 122,

  axially forwards through internal bore 102.

  The internal bore 102 comprises, on a longitudinal generatrix, a groove 124 which extends axially from the transverse wall 96 to the transverse annular face 112 which it crosses. It allows the passage of the tongue 120 of the metal connection 118 in the

  sealing partition 98 without protruding into the internal bore 102.

  The tongue 120 is mounted in the groove 124. A free front end 126 of the tongue 120 which protrudes axially towards the front of the transverse wall 96, is folded radially so as to extend along the rear transverse face of the wall 96 to ensure electrical contact with the movable contact 44 when the latter is in the rest position. The rear annular base 122 is crossed axially by the rear axial annular section 108. It provides electrical contact with the pole piece 16. For this purpose, the annular base 122 is at least flush with the face 112 so that its face transverse annular

  rear may be in electrical contact with earth 16.

  The transverse annular face 112 of the watertight partition 98 has on its circumference a peripheral sealing lip 128 which extends axially over a length greater than the thickness of

the annular base 122.

  When mounting the starter 10 a front transverse face of the rear annular base 122 is in axial abutment against the transverse annular face 112 and the lip 128 then protrudes axially from the surface

  1o rear of the rear annular base 122.

  Then, the rear axial annular section 108 is introduced axially towards the rear in the bore 110 of the polar mass 16 until a rear face of the annular base 122 comes into contact with the front radial surface of the mass polar 16. The lip 128 is then compressed against the polar mass 16. It thus seals the rear compartment 92. The deformation of the sealing lip 128 is limited by the axial bearing of the base

  rear annular 122 against the polar mass 16.

  Advantageously, a seal, such as a flexible annular lip, is placed around the rear radial end of the rear axial annular section 108. The internal diameter of this seal is less than the inside diameter of the rear axial annular section 108. L radial sealing is thus improved in particular during displacement of the rod

46.

  When the support block 26 is fixed to the casing 12 of the contactor, the sealing partition 98 is fixed axially between the support block 26 and the pole mass 16, so that the rear compartment 92 is isolated from the front compartment 90 and from the bore of the coil body. o The rear compartment 92, which is axially crossed by the barrel, is substantially annular, so that the printed circuit board 94 must also be annular. Therefore, it presents a central passage

for the barrel 100.

  As can be seen more particularly in FIG. 2, a rear section 116 of the control rod 46 is guided in axial sliding I in the rear axial annular section 108 of the internal bore 102

of the axial shaft 100.

  When the control rod 46 is in the rest position, the movable contact 44 is electrically connected to the terminal 38 by means of the second end 74 of the tab 66. It is supported on the free front end 126 of the tongue 120 itself in contact with the pole ground 16. The electrical contact is thus established between the

  38 head of terminal 30 and pole ground 16.

  In a second embodiment, the free front end 126 o of the tongue 120 and the rear annular base 122 of the metal connection 118 are preformed. The sealing partition 98 is overmolded around the metal connection 118 which constitutes an insert embedded in the partition 98. The contact faces of the free front end 126 and of the rear annular base 122 are free of any trace of material.

  insulating to ensure good electrical contact.

  The invention therefore allows good sealing of the front 90 and rear 92 compartments without electrical connections external to the contactor. A single additional small piece, the metal connection 118, is necessary to establish the grounding, and its realization in the form of a sub assembly with the partition

  imperviousness 98 simplifies assembly operations.

Claims (8)

  1. Contactor (10) for a motor vehicle starter, of the type comprising a movable contact (44) capable of being moved in translation, by a control rod (46) belonging to control means, between a rest position in which the contact (44) is in abutment against a fixed conductive element connected to a polar mass (16) of the vehicle and towards which it is biased by elastic return means (54), and an active position, in which the movable contact establishes the electrical connection between an input terminal (28) of the current 10, connected to the positive terminal of the vehicle battery, and a supply terminal (30) of the starter motor, of the type in which means internal to the contactor which, when the movable contact (44) is in the rest position, make it possible to establish electrical contact between the power supply terminal (30) and the electrical ground of the vehicle by means of the movable contact (44 ), and type in which the elastic return means (54) are arranged between the movable contact (44) and a support block (26) of the terminals (28, 30) made of insulating material, characterized in that it comprises a partition d sealing (98) which separates, in a space (45) delimited inside the support block (26), a sealed front compartment (90) in which the terminals (28, 30) and the contact plate ( 44), and a sealed rear compartment (92), in which an electronic circuit (94) is arranged, and in that said contact means which electrically connect the movable contact (44) to the pole ground (16), when it is in the rest position, are a   metal connection (118) which passes through the sealing partition (98).   2. Contactor according to the preceding claim, characterized in that the sealing partition (98) comprises a transverse wall (96) before radial orientation and an axial barrel (100) which is crossed by the control rod (46) and which comprises a front axial annular section (106) and a rear axial annular section (108) connected by a face transverse annular (112).   3. Contactor according to claim 2, characterized in that the so-called transverse annular face (112) has an axial hole for   allow passage of the metal connection (118).   4. Contactor according to any one of the claims   previous, characterized in that the metal connection (118) comprises a rear annular base (122) which is axially crossed by the rear axial annular section (108) and which is interposed axially between said transverse annular face (112) and the polar mass (16), and has a tongue (120) which extends axially forwards from the rear annular base (122) through the axial shaft (100) and the front free end (126) of which is in contact with   the movable contact (44) when in the rest position.   5. Contactor according to any one of claims 2 to 4,   characterized in that the sealing partition (98) is produced by molding in electrically insulating material, and in that the metallic connection (118) is embedded in the sealing partition (98) so that its faces which ensure the electrical contact between the pole ground (16) and the movable contact (44) are free from any trace of material which alter the electrical contact.   6. Contactor according to one of the preceding claims,   characterized in that the transverse annular face (112) has a peripheral lip (128) which cooperates with a radial surface before the polar mass (16).   7. Contactor according to any one of the claims   previous, characterized in that a seal is placed on the rear radial end of the rear axial annular section (108) so as to seal between a rear section (116) of the control rod (46) and the sealing partition (98) during movement of the movable contact (44).   8. Motor vehicle starter, characterized in that it   comprises a contactor according to any one of the claims previous.