FR3089570A1 - Electric starter for internal combustion engine equipped with a dust protection system - Google Patents

Abstract

The invention relates to an electric starter for a heat engine, in particular for a motor vehicle, comprising: - an electric machine (130) comprising an internal shaft (140) movable in rotation, a rotor (132) carried by the internal shaft and a stator (131) mounted around the rotor, the internal shaft driving an output shaft (120) by means of a reduction unit (190), and - a dust-proof system (200) mounted between the electric machine (130 ) and the reduction unit (190) and comprising at least one rotating deflector (210), integral with the internal shaft (140) so as to protect the reduction unit from dust transmitted by the electric machine Figure for the abstract: Figure 3A

Description

Description

Title of the invention: Electric starter for thermal engine equipped with a dust-proof system

Technical area

The present invention relates to an electric starter of a heat engine in which a dust-proof system is mounted between the electric machine and the reduction unit.

The invention finds applications in the field of motor vehicles and, in particular, in the field of vehicles whose starter is equipped with a speed reducer assembly by planetary gear.

Prior art

In a manner known per se, the role of a starter is to give the impulse necessary to start the combustion engine of a vehicle. For this, the starter comprises an electric machine electromagnetically controlled and mechanically connected to the heat engine.

An example of a starter according to the prior art is shown, in a schematic view in longitudinal section, in Figure 1. The starter 10 comprises a friction starter 11 provided with a drive pinion 12 mounted movable in translation on an output shaft 20, or drive shaft. The launcher 11 can pass from a rest position in which the drive pinion 12 is disengaged from a crown 15 for starting a combustion engine to an active position in which the drive pinion 12 engages with the starting crown 15, and vice versa a.

For this purpose, the starter 10 comprises an electric machine 30 composed of a stator 31 and a rotor 32 mounted coaxially. The stator 31 surrounds the rotor 32, which is mounted on an internal shaft 40, or rotor shaft, inside a cylinder head 50. The cylinder head 50 is integral with a support 60 of the starter intended to be fixed on a fixed part of the motor vehicle. The stator 31 comprises, for example, an inductor winding or magnets distributed on the internal face of the stator yoke 36. The rotor 32, mounted on the internal shaft 40, comprises a pack of sheets provided with grooves for mounting electrical conductors in the form of pins. These conductors are interconnected to form a rotor winding in connection with conductive blades belonging to a collector 33 secured to the internal shaft 40 and cooperating with brushes 34. The output shaft 20, positioned longitudinally along the same axis X that the internal shaft 40 has its front end mounted to move in rotation in a front bearing 70. The internal shaft 40 has its rear end mounted in a bearing of a rear bearing 80, of which is attached a brush holder 35 .

The starter 10 further comprises a reduction unit 90, mounted between the internal shaft 40 and the output shaft 20, one end of which is connected to the internal shaft 40 and the other end of which is connected to the output shaft 20. The reduction assembly 90 is a planetary gear comprising a cylindrical ring 91 internally toothed and immobilized in rotation. The teeth of the crown 91 mesh with satellite pinions mounted for rotation about axes carried by a transverse plate 92 secured to the rear end of the output shaft 20.

The starter 10 further comprises a system for moving the launcher 11 to move said launcher from its rest position to its active position and vice versa. This movement system comprises an electromagnetic contactor 13 extending parallel to the electric machine 30 and a control lever 14 in the form of a fork. The group of brushes 34 is provided for the electrical supply of the winding of the rotor 32. At least one of the brushes 34 is electrically connected to the starter ground, for example the support 60, and at least another of the brushes 34 is electrically connected to an electrical terminal 18 of the contactor. The brushes 34 rub against the blades of the collector 33 when the rotor 32 is rotating. The contactor 13 comprises, in addition to the terminal 18 connected to the brush, a terminal 16 intended to be connected to a positive electrical supply of the vehicle, for example a battery.

In such a type of starter, the electric machine 30, and in particular the brushes 34, generates dust which is transmitted, by the different sets of rotations and translations, inside the epicyclic train of the reduction unit 90. However, this dust pollutes the grease present in the reduction unit, which generates various problems such as, for example, the loss of mechanical power in the reduction unit, the reduction in the lubricating power of the grease and the acceleration of wear of the planetary gear parts.

Starter manufacturers have proposed seals of the type intended to prevent the passage of dust in the reduction unit. One of these devices is shown in Figures 2A and 2B. This device is a seal 93 mounted at the inlet of the reduction unit 90, just before the cylindrical crown 91. However, such a seal does not constitute a sufficient barrier to protect the reduction unit from dust because the dust accumulates on the joint eventually penetrate inside the cylindrical crown.

Summary of the invention

To respond to the problems mentioned above relating to the penetration of dust inside the reduction unit, the applicant proposes a dust-proof system mounted upstream of the starter reduction unit to prevent dust from d '' until reaching the reduction unit.

According to a first aspect, the invention relates to an electric starter for a heat engine, in particular for a motor vehicle, comprising an electric machine comprising an internal shaft movable in rotation, a rotor carried by the internal shaft and a stator mounted around the rotor, the internal shaft driving an output shaft via a reduction unit. This starter is characterized by the fact that it comprises a dust-protection system mounted between the electric machine and the reduction unit and comprising at least one rotating deflector, integral with the internal shaft so as to protect the reduction unit from dust. transmitted by the electric machine.

Such a starter has the advantage of preventing the dust generated by the electric machine from entering the reduction unit.

Advantageously, the anti-dust system further comprises a first stationary deflector, integral with the stator of the electric machine.

The interaction of the rotating deflector and the stationary deflector further improves protection against dust.

The starter according to the invention may include one or more of the following characteristics:

- The first stationary deflector is fixed to a cylinder head of the starter.

- The first stationary deflector is secured to the magnet positioning clips of the stator and forms, with said clips, a single piece.

- The clips have an end opposite to one end fixed on the deflector, closed to prevent the passage of dust. The obturation can be obtained by folding the clip.

- the anti-dust system includes a second stationary deflector, secured to a fixed part of the reduction unit.

- the rotating deflector and at least one of the stationary deflectors are in interaction so that the rotating deflector repels dust and the stationary deflector collects said dust.

- the rotating deflector is a sheet metal part of a substantially conical shape hollowed out at its center and mounted tightly around the internal shaft.

- The sheet metal part comprises, at the edge of the recessed area, an inner clamping ring.

- The sheet metal part has, at the edge of the recessed area, fixing claws.

- The portion of substantially conical shape of the sheet metal part is extended radially by a flat crown, one face of which is crenellated.

- The first stationary deflector is a sheet metal part in the form of a hollow crown.

- The sheet metal part has, on its inner contour, a plurality of fixing claws.

- the second stationary deflector is a sheet metal part of a substantially conical shape hollowed out at its center and extended radially by a flat crown, the conical part of said part being free around the internal shaft.

- the flat crown of the sheet metal part has a notched area extending between the conical part and a fixing ring.

- the notched area of the second stationary deflector is adapted to fit into the crenellated face of the rotating deflector.

- The flat crown of the sheet metal part has two flat concentric zones, separated by an accordion zone.

- Each of the sheet metal parts forming the rotating and stationary deflectors are produced by stamping.

- the anti-dust system has dust evacuation openings made in the starter cylinder head.

According to a second aspect, the invention relates to an electric starter for a heat engine, in particular for a motor vehicle, comprising an electric machine comprising an internal shaft movable in rotation, a rotor carried by the internal shaft and a stator mounted around the rotor, the internal shaft driving an output shaft via a reduction unit. This starter is characterized by the fact that it includes a dust-proof system mounted between the electric machine and the reduction unit and comprising at least one stationary first deflector, integral with the stator of the electric machine and protecting the reduction unit from dust. transmitted by the electric machine.

Advantageously, the anti-dust system further comprises a rotating deflector, integral with the internal shaft.

Brief description of the drawings

Other advantages and characteristics of the invention will appear on reading the description, illustrated by the figures in which:

1. [Figure 1], already described, shows a longitudinal sectional view of a thermal engine starter according to the prior art;

2. The [Figure 2A] and [Figure 2B], already described, represent perspective views, respectively, of a reduction unit equipped with a dust seal and a dust seal according to the prior art;

3. [Figure 3A] shows a longitudinal sectional view of a thermal engine starter according to the invention;

4. [Figure 3B] shows a longitudinal sectional view of the part of the starter of Figure 3A in which is housed the anti-dust system;

5. [Figure 4A], [Figure 4B] and [Figure 4C] represent examples of a rotating deflector of the starter dust protection system according to the invention;

1. [Figure 5A], [Figure 5B], [Figure 5C] and [Figure 5D] show examples of a rotating deflector of the starter dust system according to the invention;

2. [Figure 6A], [Figure 6B], [Figure 6C] and [Figure 6D] show examples of a stationary deflector of the starter dust system according to the invention;

3. [Figure 7A], [Figure 7B], [Figure 7C], [Figure 7D] and [Figure 7E] show examples of a stationary deflector of the starter dust system according to the invention;

4. [Figure 8] and [Figure 9] show views in longitudinal section of other embodiments of the starter dust system according to the invention;

5. Figure 10] shows a partially exploded perspective view of an embodiment of the starter dust protection system according to the invention

The [fig. 11] shows a perspective view of an example of a starter cylinder head according to the invention.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT An exemplary embodiment of an electric starter for an internal combustion engine, equipped with a dustproof system located between the electric machine and the reduction unit, is described in detail below, with reference to the accompanying drawings. This example illustrates the characteristics and advantages of the invention. It is however recalled that the invention is not limited to this example.

In the figures, identical elements are identified by identical references. For reasons of readability of the figures, the size scales between the elements represented are not respected.

Figure 3A shows a sectional view of an electric starter according to the invention. The electric starter 100 - called simply a starter later comprises an electric machine 130 mounted around the internal shaft 140 and a reduction unit 190 mounted between the internal shaft 140 and the output shaft 120. The output shaft 120 and the internal shaft 140 are positioned longitudinally along the same axis X, the output shaft 120 having its front end mounted to move in rotation in the front bearing 170, the internal shaft 140 having its rear end mounted in the rear bearing 180. The reduction unit 190 is a planetary gear whose role is to adapt the torque between the internal shaft 140 and the output shaft 120.

The electric machine 130, the reduction unit 190 and all the other components of the starter 100 of the invention have an operation similar to that of the starter of the prior art except that the starter 100 of the invention comprises a system anti-dust repelling the dust generated by the electric machine 130 far from the entry of the reduction unit 190. In fact, in the starter of the invention, the anti-dust system 200, an example of which is shown in enlarged section in FIG. 3B, comprises at least one deflector, mobile or fixed, which makes it possible to move the dust away from the inlet of the reduction unit to avoid any accumulation of dust near said reduction unit 190.

In some embodiments, the anti-dust system 200 includes a rotating deflector 210 secured to the internal shaft 140. When the electric machine 130 is in operation, the internal shaft 140 drives the rotating deflector 210 in rotation, generating a centrifugal effect. As shown in FIGS. 3A, 3B and 5A to 5D, the rotating deflector 210 generally has a shape of a cone hollowed out at its center, that is to say of which the top has been topped. With the centrifugal effect, the conical shape of the rotating deflector 210 repels dust away from the inlet of the reduction unit 190.

In some embodiments, shown in particular in Figures 5B, 5C and 5D, the rotating deflector 210 has a first portion 211 in the form of a truncated cone and a second portion 212 in the form of a ring. This second portion 212 forms a clamping ring 212 mounted on the edge of the recessed area 214 of the first portion 211, in the reverse of the constricted area 216 of said first portion 211. This clamping ring 212 is adapted to be mounted clamped around of the internal shaft 140 and, thus, secure the rotating deflector 210 with the internal shaft 140.

The rotating deflector 210 can be, for example, made of stamped sheet metal, as shown in Figure 5D, or by machining, as shown in Figure 5C. Depending on the manufacturing method chosen, the internal zone of the portion 211 in the form of a truncated cone can be hollow or solid, with a smooth or crenellated surface.

According to a variant shown in section in particular in Figures 8 and 9, the portion 211 in the form of a truncated cone is extended radially by a discharge crown 218 extending, for example, to the end of the diameter of the rotor 132. The surface of this evacuation ring 218 can be smooth or crenellated, as explained in more detail below.

As shown in Figure 5A, the rotating deflector 210 is mounted on the internal shaft 140 so that the flared base 215 of the portion in the form of a truncated cone 211 is directed towards the reduction unit 190, the area constricted 216 of the truncated cone-shaped portion 211 being directed towards the rotor 132 of the electric machine 130. With such an assembly, the rotating deflector 210, under the effect of the rotation, evacuates the dust coming from the electric machine 130 and passing through the rotor 132 and the internal shaft 140 away from the internal shaft 140 and therefore from the inlet of the reduction unit 190.

Alternatively, the internal rotation shaft 140 has a circular protrusion 141 around which the clamping ring 212 is fixed. This makes it possible to guarantee good sealing.

In certain embodiments, shown in particular in FIGS. 4A, 4B and 4C, the rotating deflector 210 comprises a portion 211 in the form of a truncated cone and an attachment zone 213. The portion 211 in the form of a truncated cone can be identical to the portion 211 of FIGS. 5A-5D. The attachment zone 213, located at the edge of the constricted zone 216 of said portion 211, comprises a plurality of claws distributed over the contour of the constricted zone and adapted to grip the internal shaft 140. These claws of the zone grip 213 can take the form, for example, of the claws of a Grifaxe® washer.

In some embodiments, the anti-dust system 200 includes a first stationary deflector 220, integral with the stator 131 of the electric machine 130. An example of this first stationary deflector 220 is shown in Figures 6A, 6B and 6C . This first stationary deflector 220, also called a fixed baffle, has the shape of a crown fixed on a fixed part of the electric machine 130, for example on the cylinder head 150, and closing the passage between the stator 131 and the rotor 132 of the electric machine. 130. In fact, as shown in FIG. 6A, the stator 131 comprises permanent magnets 154 distributed over the internal contour of the cylinder head 150 and fixed to said cylinder head 150 by clips 155. The rotor 132 being mounted movable inside of the stator 131, there is a path 137, between the rotor 132 and the magnets 154 and the staples 155 of the stator, through which pass the dust generated by the brushes of the electric machine 130. In the embodiments of FIGS. 6A-6C , the fixed baffle 220 is mounted on the cylinder head 150 so as to close the path 137 and prevent the dust from passing, via the path 137, to the reduction unit 190.

In the examples of Figures 6B and 6C, the fixed baffle 220, for example made of stamped aluminum sheet, has a hollow washer 221 and a plurality of fixing lugs 222 distributed over the outer contour of said hollow washer 221. The fixing lugs 222 ensure the fixing of the fixed baffle 220 on the cylinder head 150. These fixing lugs can, for example, be claws crimped at the end of the stator, in the housings dedicated to staples 155 of the cylinder head 150. The fixed baffle 220 is mounted at the end of the stator 131 with its curved face 221 opposite the path 137 so that the dust passing through said path 137 is stored inside the fixed baffle 220.

In one embodiment shown in Figure 6D, the fixed baffle 220 is mounted directly on the clips 155 for fixing the magnets 154 of the stator 131. In this embodiment, the fixed baffle 220 includes a hollow washer 221 equipped a plurality of staples 155 distributed along the outer contour of said hollow washer 221. This fixed baffle 220, for example made of stamped aluminum sheet, is mounted axially in the stator 131 so that each staple 155 is housed between two magnets 154 and that its curved face is opposite the path 137 of dust transit. The fixing of the staples in the cylinder head 150 ensures the fixing of the fixed baffle 220. This fixed baffle 220 has an additional advantage compared to the embodiments of FIGS. 6A-6C, namely the ease of mounting in the stator 131.

In some embodiments, the anti-dust system 200 comprises a second stationary deflector 230, integral with a fixed part of the reduction unit 190. Examples of this second stationary deflector 230 are shown alone, in the figures 7A and 7B, and mounted on the reduction unit, in FIGS. 7C to 7E. This second stationary deflector 230, also known as a reduction gear baffle, forms a cover suitable for fitting and enclosing at least part of the components 191 of the reduction gear assembly 190. This reduction gear baffle 230 is mounted on the reduction gear assembly 190, like a cover closing said reducing assembly. The gearbox baffle 230 can be mounted on the upstream face 192 of the gearbox assembly 190, for example, by force or else by interlocking and locking by means of locking elements 193 such as keys, distributed over the contour of the reducer assembly.

The gearbox baffle 230 may, for example, be a sheet metal part in the form of a conical chimney, which comprises a cone 231 hollowed out in its center and extended radially by a flat crown 232. The recess 234 of the cone 231 allows the gearbox baffle 230 to be traversed by the internal shaft 140 so that said gearbox baffle 230 is mounted free around said internal shaft.

In some variants, such as that shown in FIGS. 7A and 7C, the flat crown 232 has a flat zone 236 extended axially by an accordion zone 233, itself extended radially by a flat zone 235. The flat crown 232 thus comprises two concentric flat zones 235, 236, separated by an accordion zone 233 extending axially, in a direction substantially parallel to the internal axis 140. This concentric succession of plane zones 235, 236 and accordion zone 233 allow the gearbox baffle 230 covers the upstream face 192 of the gearbox assembly 190 in order to protect said gearbox assembly from dust.

In certain variants, the flat crown 232 of the gearbox baffle 230 comprises, as shown in FIGS. 7B, 7D and 7E, a notched zone 237 extending radially between the cone 231 and a fixing ring 238 and a flat area 235 extending radially beyond said fixing ring 238 and closing the upstream face 192 of the reduction unit. The fixing ring 238 can form the last notch of the notched zone 237, as in the example of FIG. 7D, or else extend axially, in a direction substantially parallel to the internal axis 140, as in the example of Figure 7E.

According to certain embodiments of the invention, at least two of the rotating and / or stationary deflectors, which have just been described, can be associated and interact to further improve the evacuation of dust. In fact, the rotating deflector 210 removes, by centrifugal effect, the dust from the entry zone of the reduction unit 190, that is to say from the zone close to the internal shaft 140. The fixed baffle 230 prevents the transit of dust through the spaces between the rotor 132 and the magnets of the stator 131. The reduction gear baffle 220 forms a dust retention barrier on the upstream face 192 of the reduction unit. The fact of combining two or three of these deflectors and baffles makes it possible to combine the effects of the removal of the dust upstream of the reduction unit 190 so that the dust cannot penetrate said reduction unit 190. A semi-exploded view of the junction zone of the electric machine 130 with the reduction unit 190 is shown in FIG. 10, in which the positioning of the three deflectors and baffles with respect to each other is shown.

Figure 8 shows, in a longitudinal sectional view, a variant of the association of three deflectors and baffles 210, 220, 230. In this variant, the fixed baffle 220 is as described above and the rotating deflector 210 and baffle of reducer 230 have shapes interacting with each other. More specifically, the rotating deflector 210 comprises a discharge crown 218 which extends radially from the flared base 215 of the truncated cone-shaped portion 211 over the entire length of the radius of the rotor 132, this discharge crown 218 allowing collect the repelled dust by centrifugation. In the example of FIG. 8, the evacuation ring 218 has a crenellated surface 219, on its face opposite the reduction unit 190. This crenellated surface 219 has the effect of making the dust trajectory more complex so that it these remain localized in the evacuation crown 218.

In the example of Figure 8, the slots of the crenellated surface 219 have shapes and dimensions corresponding to the notched area 237 of the regulator baffle 230. Indeed, in this example, the notched area 237 and the crenellated surface 219 are inserted into one another to further complicate the trajectory of the dust and collect said dust in the interstices 217.

Figure 9 shows, in a longitudinal sectional view, another variant of the association of two of the deflectors and baffles 210, 220, 230. In this variant, the rotating deflector 210 comprises a discharge crown 218 such as described above. This discharge crown 218 extends radially from the flared base 215 of the truncated cone-shaped portion 211 over the entire length of the radius of the rotor 132. In this variant, and as described above, the regulator baffle 230 comprises a notched area 237, the notches of which have shapes and dimensions corresponding to the crenellated surface 219 of the evacuation crown 218. The regulator baffle 230 further comprises a fixing ring 238 which extends axially up to the air gap 133 separating the rotor 132 from the stator 131 so as to close the path 137 for the transit of dust. By the specific shape of the regulator baffle 230, this embodiment makes it possible to obtain an effect similar to that of the embodiment of FIG. 8, with only two baffles and baffles.

In some embodiments described above, and in particular in the embodiments of Figures 3A, 3B and 8, it is possible to evacuate the dust received by the deflectors and baffles 210, 220, 230 outside the starter. For this, the starter cylinder head 150 is provided with one or more through holes 151, as shown in FIG. 11. These through holes 151, of various shapes and sizes, are produced in the cylinder head, for example, at right fixed baffle 220, between said fixed baffle 220 and the reduction baffle 230. These through holes 151 allow, when the internal shaft 140 is in rotation, to evacuate the dust subjected to the centrifugal effect out of the starter.

Although described through a certain number of examples, variants and embodiments, the starter according to the invention includes various variants, modifications and improvements which will be obvious to those skilled in the art, it being understood that these variants, modifications and improvements are part of the scope of the invention

Claims (1)

Claims [Claim 1] Electric starter for a heat engine, in particular for a motor vehicle, comprising an electric machine (130) comprising an internal shaft (140) movable in rotation, a rotor (132) carried by the internal shaft and a stator (131) mounted around the rotor , the internal shaft driving an output shaft (120) by means of a reduction unit (190), characterized in that it comprises a dustproof system (200) mounted between the electric machine (130) and the reduction unit (190) and comprising at least one rotating deflector (210), integral with the internal shaft (140) so as to protect the reduction unit from dust transmitted by the electric machine. [Claim 2] Starter according to claim 1, characterized in that the anti-dust system (200) further comprises a first stationary deflector (220), integral with the stator (131) of the electric machine. [Claim 3] Starter according to either of Claims 1 and 2, characterized in that the dust-protection system (200) comprises a second stationary deflector (230), integral with a fixed part of the reduction unit (190). [Claim 4] Starter according to any one of Claims 1 to 3, characterized in that the rotary deflector (210) is a sheet metal part of a substantially conical shape (211) hollowed out at its center and mounted tightly around the internal shaft ( 140). [Claim 5] Starter according to claim 4, characterized in that the sheet metal part comprises, at the edge of the recessed area, a plurality of fixing claws (213). [Claim 6] Starter according to any one of claims 2 to 5, characterized in that the first stationary deflector (220) is a sheet metal part in the form of a hollow crown (221). [Claim 7] Starter according to any one of Claims 2 to 6, characterized in that the first stationary deflector (220) is fixed to a cylinder head (150) of the starter. [Claim 8] Starter according to any one of Claims 2 to 6, characterized in that the first stationary deflector (220) is integral with staples (155) for positioning the stator magnets (131) and forms, with said staples, a single room. [Claim 9] Starter according to any one of Claims 3 to 8, characterized in that the second stationary deflector (230) is a sheet metal part of a substantially conical shape (231) hollowed out at its center and extended radially by a flat crown (232), the conical part of said part being freely mounted around the internal shaft (140). [Claim 10] Starter according to any one of claims 1 to 9, characterized in that the anti-dust system (200) comprises openings (151) for evacuating the dust produced in the cylinder head (150) of the starter.