Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
  • H02K5/173—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings
  • H02K5/1732—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings radially supporting the rotary shaft at both ends of the rotor
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/10—Casings or enclosures characterised by the shape, form or construction thereof with arrangements for protection from ingress, e.g. water or fingers
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K5/00—Casings; Enclosures; Supports
  • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
  • H02K5/12—Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas
  • H02K5/124—Sealing of shafts

Definitions

• the invention relates to an alternator for a motor vehicle.
• an alternator is a rotary electrical machine, which comprises a rotor secured to a shaft and a stator on each of which is produced an electrical winding.
• the rotor and stator are mounted in a housing.
• the stator has three windings so that the alternator is of the three-phase type.
• the alternator is of the hexaphase type.
• the alternator transforms a rotational movement of the rotor into an induced electric current at the stator.
• the alternator can also be reversible and constitute a motor which makes it possible to transform an electric current which passes through a winding of the stator into a rotational movement of the rotor.
• This reversible alternator is called an alternator-starter and makes it possible to transform mechanical energy into electrical energy and vice versa, in particular to start the engine of the motor vehicle or to constitute an auxiliary engine.
• the generator housing has a front bearing centrally provided with a housing delimited by a transverse wall for mounting a sealed ball bearing rotationally supporting the end, called the front end, of the shaft carrying a pulley secured in rotation of the shaft.
• a first spacer possibly in one piece with the pulley, is interposed between the pulley and the inner ring of the ball bearing.
• Water can get inside the housing. Water is generally charged with particles, see muddy, in particular in the case of motor vehicles of the 4x4 or heavy goods type. For this reason, the ball bearing has reinforced seals to improve its seal.
• the object of the present invention is, in the case of severe applications, to increase, in a simple and economical manner, the lifetime of the alternator without excessively increasing the size of the alternator.
• an alternator of the above-mentioned type is characterized in that the barrier against the penetration of water is in the form of a washer distinct from the first spacer and is, on the one hand crossed by the shaft and, d 'other hand, pressed against the inner ring of the ball bearing and in that the barrier is integral in rotation with the inner ring of the ball bearing and the pulley.
• the barrier is in contact with the internal ring of the ball bearing and creates an obstacle preventing the penetration of water into the bearing level so that the bearing seals can be more economical.
• the barrier is integral in rotation with the shaft so that it is economical; no friction lip on the shaft being to be expected. Because the barrier is in contact with the inner ring of the ball bearing, the first spacer is unchanged so that the barrier can be mounted at will. In addition, a small gap exists between the barrier and the adjacent seal of the bearing.
• an air movement occurs between the barrier and the adjacent seal of the bearing integral in rotation with the outer ring of the ball bearing because these two parts are rotatable with respect to one another. Water cannot therefore penetrate due to the movement of air. Thus, no fat or other paste is provided.
• the solution is economical and compact, especially axially, because the barrier is in the form of a washer.
• the alternator can therefore be subject to severe use and therefore be fitted to 4x4 or heavy goods vehicles.
• the barrier consists of an embodiment in a simple metal washer.
• the barrier is pinched at its internal periphery between the internal ring of the ball bearing and the first spacer.
• the axial size of the alternator is generally unchanged since the barrier may have a small thickness at its internal periphery.
• the barrier is an external part to the bearing, which makes the solution economical.
• a small axial clearance exists between the transverse wall of the front bearing and the barrier to avoid any contact or interference between two rotating parts with respect to each other and to make the barrier economical.
• the barrier extends radially to the vicinity of the inner periphery of the outer ring of the ball bearing, so that the annular space between the two rings of the bearing is well masked by the barrier without the the radial size of this barrier is important.
• a slight clearance therefore exists between the internal periphery of the outer ring and the external periphery of the barrier to allow air movement. This play can be increased so that the outer periphery of the barrier extends to the vicinity of the average diameter of the balls of the bearing. It all depends on the applications.
• the barrier is installed thanks to a reduction in thickness which the transverse wall of the front bearing comprises below the outer ring of the ball bearing, so that the available space is used without increasing the size. .
• an additional barrier against the penetration of water is crossed by the rotor shaft and is mounted on the side of the ball bearing opposite the first barrier, being pressed against the inner ring of the ball bearing.
• This additional barrier is integral in rotation with the inner ring of the ball bearing and the pulley.
• the additional barrier is constructed in the image of the first barrier so that the same advantages are found in particular with regard to the axial bulk and an air movement between the additional barrier and the adjacent seal of the bearing.
• the barrier additional is clamped at its internal periphery between the internal ring of the ball bearing and a second spacer interposed axially between the internal ring of the ball bearing and a plate secured to the rotor shaft and belonging to a pole wheel that includes the rotor.
• This barrier is therefore independent of the bearing.
• the additional barrier and in the form of a washer and consists, in one embodiment, of a simple metal washer.
• the two barriers each in the form of a metal washer, advantageously consist of a foil by definition of thin thickness.
• the foils have in one embodiment a thickness of 0.3 mm so that they have good rigidity, while minimizing the increase in the axial size of the alternator.
• the pinch solution is preferable from this point of view.
• the consumption of barrier material is minimal.
• the invention takes advantage of the labyrinth existing between the first spacer and the transverse wall of the front bearing to seal the latter using the first barrier.
• FIG. 1 is a view in axial half-section of an alternator produced according to the invention.
• This figure shows a multi-phase alternator, here three-phase, for a motor vehicle mainly consisting of a metallic casing 12 in two parts 15, 17 connected to the mass of the motor vehicle and internally carrying two main members which are a stator 14 and a rotor 16 as described for example in document US A 527 605 (EP B 0 515 259) to which reference will be made for more details.
• the parts 15, 17 therefore comprise lugs for their attachment to a fixed part of the vehicle.
• the stator 14 surrounds the rotor 16, which is integral with a rotor shaft 18 on the rear end of which two slip rings 20 are fixed, while a pulley 30 is integral with the front end of the shaft 18.
• This pulley here grooved, is intended to receive a belt of complementary shape forming part of a movement transmission device driven by the internal combustion engine of the motor vehicle.
• the stator 14 is composed of a cylindrical body 22 which is here mainly constituted by an axial stack of transverse sheets of soft iron.
• the inner annular face of the body 22 has axial grooves, which extend radially outward and which receive axial strands of electrical windings 32.
• the grooves are open inwardly being semi-closed as visible for example in the document FR A 2 603 429.
• Each electric coil 32 is for example constituted by the winding in turns of an electrically conductive element, here a copper wire, which is coated with at least one layer of electrically insulating material, for example a polyester in two layers one of the polyide type, the other of the polyamide imide type.
• the axial strands are extended by transverse junction strands which form buns (not referenced) extending projecting on either side of the body 22 of the stator 14, in accordance with FIG. 1.
• conductors in the form of bars are used, such as pins generally in the shape of a U, of circular or rectangular section, mounted in the axial grooves of the stator 14 as described in document WO-92/06527 .
• conductors in the form of bars are used, such as pins generally in the shape of a U, of circular or rectangular section, mounted in the axial grooves of the stator 14 as described in document WO-92/06527 .
• four electrically conductive elements are mounted radially with superposition by groove as described in application FR 01 04770 filed on 04/20172001 and published under the number FR A 2 820 896 or in application FR A 2 819 117.
• the rotor 16 is here a claw rotor provided with an electric coil 62 of cylindrical excitation, which is mounted between two metal plates 64 and 66 each having claws at their outer periphery, which extend axially in the direction of the other plate 66 and 64.
• the ends of the winding 62 are connected to the rings 20 in known manner by wire connections.
• the plates 66, 64 are here extended at their internal periphery by a cylindrical portion to carry the coil 62.
• a cylindrical core is mounted on the shaft 18 and is interposed between the two plates to carry the coil 62.
• Each plate assembly -griffes constitutes a polar wheel here in magnetic steel.
• Each pole wheel is fixed to the shaft by means of knurled parts of this shaft 18.
• each plate 64,66 carrying a fan respectively 102,104 adjacent to the part 15,17 concerned of the casing.
• Each part 15, 17 of casing 12 is perforated for air circulation and centrally carries a ball bearing 26, 28 for support for rotation of the front and rear ends of the shaft 18 respectively.
• the front bearing 15 the one adjacent to the pulley 30
• the rear bearing 17 carries an arrangement 23 for rectifying the alternating current produced by the stator and a brush holder 25, the brushes of which cooperate with slip rings 20.
• the rectifying arrangement 23 comprises the rear bearing 17 carrying the so-called negative diodes, a positive metallic radiator carrying the so-called positive diodes and a connector interposed between the rear bearing and the positive radiator, in particular for connecting the diodes as described in document FR A 2 734 425 to which reference will be made for more details.
• the front 15 and rear 17 bearings are metallic, here based on aluminum, being of hollow form delimited by a transverse flange carrying the ball bearing 26, 28 concerned and by a peripheral rim of axial orientation, one of which is here internally.
• the bearing 17 also has a shoulder so that the body 22 is clamped between the two shoulders of the bearings 15,17.
• the flanges and the flanges in known manner, have openings for air circulation inside the machine generated by the rotation of the fans 102, 104.
• the flanges have air outlet openings facing the axial ends of the windings 32, called the chignon, extending in axial projection relative to the body 22 of the stator 14, while the flanges have air inlet openings facing the blades of the fans 102, 104.
• These bearings are connected to fixing using screws or tie rods as visible for example in Figure 1 of the aforementioned document EP B 0 515 259.
• a single fan is installed outside at the level of the pulley.
• the bearings 15, 17 are provided internally with channels for circulation of a coolant, such as the coolant of the engine of the motor vehicle.
• the pulley 30 is internally hollow for housing the threaded front end 40 of the shaft 18, a nut 41 and a support washer 42 interposed between the transverse bottom 43 of the pulley 18 and the nut 41 screwed onto the threaded end 40.
• the washer 42 is eliminated the nut 41 having a base, which replaces the washer 42.
• the bottom 43 is perforated centrally, as well as a first annular spacer 44 and a second annular spacer 45 , for passage of the shaft 18.
• the inner ring 50 of the ball bearing 26 is clamped on a smooth portion of the shaft 18; the spacers 44,45 being mounted on either side of this ring 50.
• the outer ring 51 of the bearing 26 is mounted in a housing formed at the internal periphery of the transverse flange 19 of the front bearing 15, that is to say centrally in the front bearing 15.
• the housing belongs to a cylindrical central core 200 of the front bearing 15, constituting a hub.
• the core 200 delimits at its external periphery the air inlet openings of the bearing 15 and is projecting axially in the direction of the rotor 16.
• the housing is delimited by an annular bearing of axial orientation 52 extended radially inwards by a wall transverse 53 surrounding the first spacer 44 with little play.
• the bearing 52 and the wall 53 internally delimit the core 200.
• the front face of the ring 51 is supported on the external periphery of the portion 53, while the rear face of the ring 51 is in contact with a retaining plate 55 of rectangular shape, as a variant in the shape of a washer, fixed by countersunk head screws (not referenced) on the flange 19, more specifically on axially and radially projecting arms of the core 200, above the bearing surface 52 in contact with the external periphery of the external ring 51.
• the range 52 is therefore a mounting range and the ring 51 is clamped axially between the part 55, serving to axially wedge the ring 51 in one direction, and the wall 53 axially wedging the ring 51 in the other direction.
• the rectangular shape of the holding plate 55 saves material and does not block the air inlets of the bearing 15.
• four screws are provided at the four corners of the plate 55 for fixing to the front bearing 15 using four screws which are screwed into tapped holes implanted here in the arms of the core 200 radially outside the mounting surface 52.
• the first annular spacer 44 is located axially between the bottom 43 of the pulley 30 and the inner ring 50 of the ball bearing 26.
• the rings 50,51 have tracks for the balls 54 interposed radially between the rings 50,51 .
• the bearing 26 is advantageously conventionally lubricated with grease and seals integral with the outer ring 51 are provided at each axial end of the bearing to prevent the grease from escaping so that the bearing 26 is sealed.
• a cage is provided for retaining the balls 54.
• the seals (not referenced) of the bearing 26 are represented by lines. These seals are set back with respect to the axial ends of the front bearing 26 which are larger in radial size than the rear bearing 28.
• the seals are integral with the outer ring 51 of the bearing and are in contact with the outer periphery of the inner ring 50.
• the first spacer 44 is of tubular shape having at its front end an annular rim of transverse orientation for contact with the bottom 43. As a variant, the first spacer is in one piece with the bottom 43 then thicker.
• the second spacer 45 is tubular in shape and is located axially between the inner ring 50 of the bearing 26 and the plate 64 of the adjacent pole wheel.
• the shaft 18 is shouldered at the rear face of the plate 66 of the other pole wheel.
• a barrier 70 against the penetration of water is located axially between the ball bearing 26 and the central transverse wall 53 of the front bearing 15.
• the barrier 70 is pressed against a characteristic of the invention against the inner ring 50 of the bearing.
• the barrier 70 according to another characteristic of the invention is crossed by the shaft 18 of the rotor 16 and is at the Figure 1 pinched at its inner periphery between the first spacer 44 and the inner ring 50 of the bearing 26 larger than the bearing 28 of the rear bearing 17 so that this barrier is integral in rotation with the inner ring 50, the pulley 30 and the rotor 16.
• the barrier 70 is in the form of a washer according to another characteristic of the invention.
• the barrier is fixed to the inner ring of the bearing and is therefore captive.
• the fixing is carried out by welding.
• the fixing is carried out by snap-fastening, the barrier comprising at its internal periphery legs or penetrating hooks each by snap-fastening in a depression formed at the internal periphery of the internal ring 50 in the vicinity of the axial end concerned of the ring 50 The depression is delimited by a projection, which is crossed by the tab or the hook during the latching operation.
• the hooks are connected to each other continuously.
• the barrier 70 is, on the one hand, in contact with the internal ring of the ball bearing by being pressed against it so as not to interfere with the adjacent seal of the bearing and, on the other hand, according to a characteristic, distinct from the spacer 44, which is not modified so that the solution is simple, economical and axially compact.
• the barrier 70 extends radially to the vicinity of the internal periphery of the external ring 51 of the bearing 26 to protect as much as possible the space between the two rings 50, 51.
• a small radial clearance therefore exists between the barrier and the outer ring 51 for air passage.
• the barrier extends to the vicinity of the mean diameter of the balls 54 so that the radial clearance is greater.
• the barrier 70 is installed by means of a reduction in thickness that the transverse wall 53 comprises below the outer ring 51 of the bearing 26 as visible in FIG. 1. This arrangement makes it possible not to increase the size of the 'alternator, while having a wall 53 sufficiently robust to support the front face of the ring 51. Here the thickness of the transverse wall 53 is reduced below the average diameter of the ring 51.
• the barrier 70 advantageously consists of a simple thin and economical metallic washer.
• This flat washer advantageously in the form of a foil, makes it possible not to overall increase the axial size of the alternator and not to modify the first spacer. The increase in size is therefore minimal.
• the barrier is well protected and is well maintained and immobilized by pinching or fixing on the internal ring.
• the washer 70 is, as a variant, at its external periphery slightly inclined in the direction of the wall 53.
• the washer carries at its external periphery a bead directed towards the wall 53 to minimize the space between the washer 70 and the wall and further prevent water penetration.
• the bead can be replaced by any suitable shape making it possible to reduce the clearance between the washer 70 and the wall 53.
• the washer 70 in a variant has reliefs in below its outer periphery to create baffles preventing water from passing through. The reliefs are directed opposite to the bearing.
• an additional barrier 80 crossed by the rotor shaft 16, is mounted on the side of the ball bearing 26 opposite the first barrier 70 to oppose the penetration of water between the two rings at the face rear of the bearing 26.
• the additional barrier 80 is pressed against the inner ring and is rotationally integral with the inner ring 50 of the ball bearing 26 and the pulley 30 like the barrier 70.
• the additional barrier 80 is in the form of a washer. .
• the additional barrier 80 is here pinched at its internal periphery between the internal ring 50 of the ball bearing 26 and the second spacer 45 interposed axially between the internal ring 50 balls 26 and the plate 64 secured to the shaft 18 of the rotor 16 and belonging to the adjacent pole wheel of the rotor 16.
• the washer 80 is captive by being fixed on the internal ring 50 in the same way as the barrier 70, for example by welding or snap-fastening. In all cases, the spacer 45 is not modified.
• the barrier extends to the vicinity of the mean diameter of the balls 54 so that the radial clearance is greater. This avoids any interference between this barrier 80 and the second seal that the bearing 26 includes between these two rings so as to oppose, serve at the outlet of the lubrication grease of the bearing while protecting at best the space between the two rings 50,51 and by promoting air movement between the barrier 80 and the adjacent seal of the bearing 26.
• the additional barrier 80 consists of a simple flat metal washer and thin for the same reasons as the washer 70.
• the axial size of the alternator is therefore increased to a minimum in a simple and economical manner.
• the foil-shaped washers 70, 80 have for example a thickness of 0.3 mm.
• the washer 80 has, as a variant, shapes at its outer periphery, such as a bead, and / or reliefs directed away from the bearing like the washer 70.
• the washer 80 is inclined at its outer periphery in the direction opposite the balls 54.
• FIG. 1 shows, due to the presence of the annular transverse rim of ⁇ spacer 44, a bearing shield of labyrinth between the first spacer 44, possibly integral with the pulley, and the central transverse wall 53 of the front bearing 15.
• This labyrinth is closed by the washer 70 so that the bearing 26 is well protected.
• at least one of the washers 70.80 is planar, the axial end concerned with the ring 50 extending in axial projection relative to the external ring 51.
• At least one of the washers 70.80 has an external part offset axially in the direction opposite to the bearing with respect to its internal periphery pinched between
• the washers 70.80 can have different heights or be the same height.
• barriers 70.80 are in contact with the internal ring of the ball bearing, which in a variant is with two rows of balls.
• the barriers are made of a material other than metallic.
• the alternator is of the reversible type and also constitutes a starter for starting the engine of the vehicle.
• This type of rotary electric machine called alternator-arrester above is described for example in the application FR 0103237 filed on 03/03/2001 and published under the number FR A 2 806 224.
• a target carrier is in this case interposed between the plate 66 and the rear bearing 28.
• the first spacer is in one piece with the pulley which, as a variant, is a possible solution.
• the alternator is devoid of brushes and is of the type described in document DE A 199 44 557 mentioned above.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Motor Or Generator Frames (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (4)

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• 2001
  • 2001-07-24 FR FR0109836A patent/FR2828028B1/fr not_active Expired - Fee Related
• 2002
  • 2002-07-22 BR BR0205794-8A patent/BR0205794A/pt not_active IP Right Cessation
  • 2002-07-22 EP EP02770044A patent/EP1410485A2/de not_active Withdrawn
  • 2002-07-22 WO PCT/FR2002/002600 patent/WO2003010872A2/fr not_active Ceased

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