FR2620774A1 - MAGNETIC SENSOR STATOR, IN PARTICULAR FOR AN IGNITION DISTRIBUTOR FOR AN INTERNAL COMBUSTION ENGINE OF A MOTOR VEHICLE - Google Patents

Abstract

The stator 11 of the magnetic sensor 10 for an ignition distributor consists of a lower plate 12 having on its periphery a plurality of pole teeth 13, an upper plate 14 on which an articulation bearing 15 is fixed, a permanent magnet 16 of annular shape, disposed between the plates 12 and 14, and an articulation means by means of which a control rod 40 urged by a vacuum advance regulator provides an angular offset of the stator 11 as a function of the vacuum. Assembly means 17 and 17a, articulation 15 and 30 and axial retention are produced by overmolding of non-magnetic material.

Description

The invention relates to a magnetic sensor stator.

  for ignition distributor for combustion engine.

  motor vehicle internal, sensor of the type comprising a rotor driven in rotation by the distributor shaft whose polar disc is provided on its periphery with a plurality of polar teeth directed in the axial direction, a stator whose lower plate comprises on its periphery a plurality of pole teeth inside which the pole teeth of the rotor pass and an annular coil, arranged between the two rotor / stator support plates and held coaxially in the housing of the

ignition distributor.

  In a known embodiment, notably represented in the patent addition certificate FR-A-2 422 833, the stator of the magnetic sensor comprises, in addition to the lower plate, a permanent magnet of annular shape, magnetized in the axial direction of the distributor. ignition and arranged coaxially between the lower plate and an upper plate in the center of which is welded by brazing a cylindrical bearing which must pivot on the distributor shaft. The assembly of the stator assembly is carried out by non-magnetic rivets crossing the three elements

  main components of said stator.

  The stator is mounted to rotate freely and is held axially on the distributor shaft by means of stop rings such as circlips anchoring in appropriate grooves made in said shaft. The stator thus mounted is capable of being angularly offset as a function of the vacuum prevailing in the pipes of the internal combustion engine. This angular stress is provided by a vacuum advance regulator acting on the stator by means of a control rod. For this the zipper carries, at its free end an axis which is articulated in a plastic cushion arranged in the stator. It can be understood from the above that the assembly of the different constituent elements of the stator and its maintenance, free to rotate, on the distributor shaft requires a plurality of specific means and operations, incompatible with mass production such as especially that of

  automotive equipment for a given market price.

  The invention overcomes these drawbacks and for this purpose relates to a magnetic sensor stator for an ignition distributor for an internal combustion engine of a motor vehicle, a sensor of the type comprising: A rotor driven in rotation by the distributor shaft. polar disc is provided on its periphery with a plurality of polar teeth directed in

the axial direction.

  - A stator made up of a lower plate provided on its periphery with a plurality of polar teeth in front of which the polar teeth of the rotor pass, an upper plate on which is fixed a hinge bearing of the stator on the shaft of the distributor, of a permanent magnet of annular shape magnetized in the axial direction of the distributor and held by assembly means between the lower plate and the upper plate and an articulation means by means of which a control rod urged by a vacuum advance regulator provides an angular offset of the

  stator as a function of depression.

  - A coil of generally annular shape disposed between the lower plate of the stator and the rotor plate and held coaxially with the shaft in the casing of the distributor, characterized in that the means of assembly, articulation and its axial retention on the distributor shaft, are produced by overmolding of non-magnetic material on at least one of the elements

of the stator.

  The following description next to the drawings

  annexed will better understand the invention: - Figure 1 shows a longitudinal sectional view of an ignition distributor using a

  magnetic sensor according to the invention.

  - Figure 2 shows a longitudinal sectional view of the stator of the magnetic sensor made along line III-III of Figure 3. - Figure 3 shows a sectional view

  transverse along line II-II of Figure 2.

  According to FIG. 1, the ignition distributor to which the invention is applied consists in a known manner of a shoemaker i surmounted by a flange bearing in the shape of a bell la at the top of which traverses and journals the shaft of the distributor driving in rotation a rotor 2 consisting of a sleeve 4 mounted to rotate freely on the shaft 3 and on which is fixed a polar disc 5 provided on its periphery with a certain number of polar teeth 6 corresponding to the number of cylinders to be ignited by the engine internal combustion. The sleeve 4 carries a feed plate 7 connected elastically to a support plate 8 integral in rotation with the shaft 7 by a feed regulator with centrifugal ignition which provides an angular offset of the feed plate 3 relative to the support plate 8 as a function of the speed of rotation of the shaft 3 and consequently of the

internal combustion engine.

  The polar teeth 6 pass during the rotation of the shaft 3, in front of corresponding polar teeth 13 arranged on the periphery of the lower plate 12 of the stator

  11 of the magnetic sensor designated as a whole by 10.

  Between the polar disc 5 of the rotor 2 and the lower plate 12 of the stator 11 is disposed a coil 20 of annular shape which is fixed coaxially to the shaft 3 by pinching its coil 21 between the boot 1 and the

  support flange 1a through a spacer 22.

  The stator 11 of the magnetic sensor 10, opposite FIGS. 2 and 3, comprises an upper plate 14. Between the lower plate 12 and the upper plate 14 is arranged, coaxially, a permanent magnet 16, which has the shape

  annular and flat, is magnetized in the axial direction.

  The upper plate 14 is capable of being articulated around the shaft 3 by means of a

level 15.

  According to a first embodiment, the bearing 15 is obtained by molding non-magnetic material such as plastic directly on the plate 14 (fig. 2). Polar teeth 14a are arranged on the upper plate, being directed axially along the shaft 3 towards the lower plate and embedded in the material

  non-magnetic component of the bearing 15.

  The polar teeth 14a are intended to direct the

  flow so that it goes through the tree 3.

  The pole teeth 14a can be attached and fixed by brazing to the upper plate 14 before overmolding the bearing 15 or else can be obtained directly by cutting and bending tabs in the central part of said upper plate 14 as shown in

the figures.

  The polar teeth 14a advantageously constitute

  means for anchoring the bearing 15 to the plate 14.

  Radially to the polar teeth 14a, notches 12a are formed on the periphery of the central opening 12b of the lower plate 12 in order to favor the passage of the magnetic flux in the determined main air gap

between the polar teeth 6 and 13.

  According to another characteristic of the invention, the assembly of the magnet 16 between the lower 12 and upper 14 plates of the stator 11 is produced by molding non-magnetic material directly in holes 17 passing through these various elements 12, 14, 16 and s flaring through countersinks 18 and 19 formed respectively on the external faces of said plates 12, 14 thereby making

by overmolding of the rivets 17a.

  According to another characteristic of the invention more particularly shown in Figures 1 and 2, at the free end 15a of the bearing 15 are arranged, arranged in a crown, anchoring lugs 15b which converge towards the axis of the bearing 15 of so as to be anchored elastically in an appropriate annular groove 3a formed in the shaft 3 for a determined axial position of the stator 11 relative to the rotor 2 corresponding to the position of the polar teeth 6 of the rotor 2 and the polar teeth 13 of the stator 11

one on the other.

  According to a variant of the invention, not shown in the drawings, the bearing 15 is obtained by overmolding the

  lower 12 and upper 14 plates assembled.

  Means of articulation of the stator 11 around the shaft 3 to provide an angular offset of the poles 13 of the stator as a function of the vacuum prevailing in the pipes of the internal combustion engine, consist in particular of a bearing 30 at the inside of which is housed

a spherical ball seat 31.

  The spherical seat 31 is adapted to receive elastically a ball joint 32 arranged at the end of a control rod 40 urged by a regulator to

depression (not shown).

  The bearing 30 has an external profile stepped so that its ends 33 and 34 which pass through corresponding holes 33a and 34a formed respectively in the upper plates 14 and lower 12 are of a diameter slightly smaller than its central part 35 remaining

crossing the magnet 16.

  This stepped shape of the pad 30 allows the

  axial maintenance of the latter in the thickness of the stator 11.

  The bearing can be produced by plastic molding and inserted, during the assembly of the stator,

  between the two lower 12 and upper 14 plates.

  Alternatively, the pad can be obtained by overmolding directly through said plates 12 and 14 assembled. It is obvious that modifications can be made to such an embodiment and its variants without departing from the scope of the invention, the number and the position of the polar teeth at the periphery of the rotor and of the stator will depend on the number of cylinders. of the internal combustion engine in question, and the overmolding operations of the assembly, articulation and axial retention means of the stator can be carried out

simultaneously or consecutively.

Claims (6)

  1) Magnetic sensor stator (10) for ignition distributor for internal combustion engine of motor vehicle, sensor (10) of the type comprising: - A rotor (2) rotated by the shaft (3) of the distributor whose polar disc (5) is provided on its periphery with a plurality of polar teeth (6) directed in the axial direction.   - A stator (11) consisting of a lower plate (12) provided on its periphery with a plurality of pole teeth (13) in front of which the pole teeth (6) of the rotor (2) pass, an upper plate ( 14) on which is fixed an articulation bearing (15) of the stator (11) on the shaft (3) of the distributor, of a permanent magnet (16) of annular shape magnetized in the axial direction of the distributor and maintained by assembly means between the lower plate (12) and the upper plate (14) and an articulation means by means of which a control rod (40) urged by a vacuum advance regulator provides an angular offset of   stator (11) as a function of the depression.   - A coil (20) of generally annular shape disposed between the lower plate (12) of the stator (11) and the plate (5) of the rotor (2) and held coaxially with the shaft (3) in the case (la) of the distributor, characterized in that the assembly means (17, 17a), and the articulation means (15, 30) and those of its axial retention (15a, 15b) on the shaft (3) of the distributor, are produced by overmolding of non-magnetic material on at least one of the constituent elements (12, 14 and 16) of the stator (11).   2) stator (11) of magnetic sensor (10) according to claim 1, characterized in that the means for assembling said stator (11) consist of holes (17) simultaneously passing through the lower (12) and upper plates ( 14) and the magnet (16) disposed between said plates (12,14), holes (17) flared by countersinks (18, 19) formed respectively on the external faces of the plates (12,14) and into which is injected   the non-magnetic material to form rivets (17a).   3) stator (11) of magnetic sensor (10), according to claim 1, characterized in that the articulation means consist of a bearing (15) having to pivot around the shaft (3) and which is obtained by overmolding directly in the open central part of the upper plate (14).   4) Magnetic sensor stator (11) (10), according to   claims 1 and 2, characterized in that the means   of articulation of the stator (11) around the shaft (3) consist of a bearing (15) which is obtained by overmolding through the central part of the lower (12) and upper (14) plates and the magnet (16) inserted between said plates (12) and (14).   ) Magnetic sensor stator (11) (10), according to   any one of claims 3 and 4, characterized in   that at one of the ends (15a) of the bearing (15) are provided anchoring pins (15b) arranged in a crown and which diverge inside said bearing (15) so as to be anchored elastically in an annular groove (3a) formed in the shaft (3) of the distributor for a determined axial position of the stator (11) relative to the rotor (4), corresponding to the position of the respective polar teeth (6, 17) of the rotor ( 2) and the stator (11), one at the level others.   6) stator (11) of magnetic sensor (10) according to claim 1, characterized in that the means of articulation of said stator (11) around the shaft (3) of the distributor as a function of the vacuum prevailing in the pipes of the internal combustion engine are constituted in particular by a bearing (30) of plastic material inside which is formed a spherical seat (31) adapted to receive the corresponding spherical ball joint (32) produced at the free end of the pull tab control (40) a vacuum regulator.   7) Magnetic sensor stator (11) (10), according to   claims 1, 2, 4, 5 and 6, characterized in that the   hinge assembly and holding means are   obtained simultaneously in the same molding operation.