FR2858368A1 - Starter for driving internal combustion engine, has belt and pulley rotatably mounted on shaft section that has front free end carried by arm that is integrated to support unit, and moving unit having rear wheel - Google Patents

Abstract

The starter has a belt and a pulley (80) that is driven in rotation by an electric motor (16) and rotatably mounted on a section of a shaft. The pulley extends towards the front at an interior of a support unit (200). A front free end of the section is carried by an arm (206) that is integrated to the support unit. A moving unit (28) has a rear wheel that drives a front drive pinion.

Description

i

    FIELD OF THE INVENTION The present invention relates to a starter system, also known as a starter, for driving a motor vehicle internal combustion engine by means of a belt.

  A known system of this type, for example from US-A-6,378,479, generally consists of an electric machine which drives a pulley which drives a belt which drives another pulley integral with the crankshaft of the combustion engine.

  The electric machine may be reversible by operating as an electric motor to cause the engine to start, and operating as a current generator when the engine has started.

  This type of belt starter has drawbacks.

  In this type of starter, the pulley continuously rotates under the action of the belt which, as soon as the thermal engine has started, is itself driven continuously in scrolling.

  The pulley is itself rotatably connected to the electric motor by means of a freewheel device and or by means of a clutch device whose characteristic is to be disengaged once the engine has started.

  Whatever the technology adopted for the clutch device, the latter, as well as the permanent rotation of the pulley require to ensure excellent guidance in rotation of the pulley to ensure the reliability of the starter.

  Indeed, when the pulley is arranged outside, it is generally arranged, cantilevered, at the free end before the shaft passing through it, and this outside the system, it is that is to say, in particular outside the housing or casing which houses all the components of the system, and in particular the electric motor, the transmission or reduction system, interposed between the electric motor and the pulley, and for example a freewheel mechanism and a contactor for the start control.

  The forces applied at the level of the different bearings or other means of rotation guidance are very important and require in particular to use large bearings that are able to withstand the forces applied permanently and this with a very high rotation speed due to the significant revolutions of the engine.

  In addition, because of the overlap of all or part of the clutch device and the electric motor shaft, or the transmission output shaft of the transmission interposed between the electric motor and the pulley, the bearings do not can be fitted only on a large diameter of the pulley.

  This results in significant costs and space, reduced reliability and durability, large bearings that are very resistant to high speed loads, for example of the order of 2000 to 18,000 revolutions per minute depending on the engine speed. thermal.

  In order to overcome these drawbacks, the invention proposes a starting system for driving a motor vehicle engine by means of a belt and at least one pulley driven in rotation by an electric motor. of the type in which the pulley: - is rotatably mounted on a section of a shaft which extends axially inside the pulley; and extends axially forward, at least in part, to the outside of a support element of generally tubular shape, characterized in that the free end before the shaft section is carried by a arm secured to the support member.

  Thanks to the presence of the reinforcement arm, the pulley is no longer mounted cantilever.

  According to other features of the invention - the arm comprises at least one first branch which extends axially forwardly from the support member and which is extended by a second branch of radial orientation which carries said free end before tree section; the arm is made in one piece with the support element; the arm is an element attached to the support element; the arm comprises at least one hole or a slot for the passage of a screw or a bolt for fixing the starter system, in particular on the engine block. a heat engine; said forward free end of the shaft section is rotatably mounted in a bore of the arm, and in that said shaft section is the front end section of a drive shaft rotatably connected with the armature shaft of the electric motor; said bore is a blind bore in which said forward free end of the shaft section is rotatably mounted with the interposition of rolling elements, in particular of needles; said forward free end of the shaft section is fixed on the arm, and said shaft section rotatably receives the front end section of a drive shaft connected in rotation with the motor armature shaft electric; said free front end of the shaft section is mounted screwed into a threaded bore of the arm; said drive shaft is connected to the armature shaft of the electric motor via at least one speed reducer, in particular of the epicyclic gear type; - A freewheel is interposed in the kinematic chain 30 between the armature shaft of the electric motor and pulley; - The freewheel is mounted axially movable relative to the axially fixed pulley; - The freewheel is slidably mounted axially on a splined section of the drive shaft; - The freewheel is integrated in the axially fixed pulley body; the axially fixed pulley is rotatably connected to a coaxial motion output member which belongs to a rotational coupling mechanism and which is capable of being rotatably connected to a movement input element of the mechanism coupling means which is rotatably connected with said drive shaft rotatably connected to the armature shaft of the electric motor, and there is provided control means for the coupling mechanism; said control means are capable of axially displacing one of the two elements of the coupling mechanism with respect to the other towards an active position to temporarily cause their coupling and thus to bind the rotating pulley with the drive shaft .

  Other features and advantages of the invention will appear on reading the description which follows for the understanding of which in reference to the accompanying drawings in which: - Figure 1 is a partial axial sectional view of a mode embodiment according to the state of the art of a starter pulley starter system in which the latter is rotated by the electric motor via a freewheel mechanism and a disengageable device; FIG. 2 is a view similar to that of FIG. 1 which illustrates a first embodiment of the invention in which the reinforcing arm, or carrying arm, is made in one piece with the support element; FIG. 3 is a diagrammatic perspective view of three-quarter front of the starting system of FIG. 2 with a section of the belt and a tensioning roller; FIG. 4 is a view similar to that of FIG. illustrates a second embodiment of the invention in which the reinforcing arm, or carrying arm, is made in one piece with the support member; FIG. 5 is a perspective view similar to that of FIG. 3, which illustrates a third embodiment in which the reinforcing arm, or carrying arm, is made in the form of an insert on the element of FIG. support; FIG. 6 is a partial view similar to that of FIG. 4 which illustrates a fifth embodiment of the invention according to which the freewheel mechanism is integrated with the pulley.

  In the following description, elements or

  identical, similar, or similar components will be designated by the same reference numerals.

  Without limitation, we will adopt front-back orientation 15 from left to right according to the orientation figure.

  The starting system for driving a heat engine, or starter, illustrated in FIG. 1 comprises an output shaft 12 or drive shaft which is rotated by the armature shaft 14 of a electric motor 16, here by means of two rear planetary gears 18 and before 19 cascaded or series, that is to say so that their reduction rate is increasing.

  The output shaft 12 and the armature shaft 14 are coaxial axis X1.

  The rear free end 20 of the output shaft 12 is guided in rotation by a rear bearing 24, with the interposition of a rear guide sleeve 25.

  A movable assembly 28 includes a rear freewheel 30 which drives a front gear 32. The movable assembly 28 is mounted to slide axially on a splined intermediate section 34 of the output shaft 12 so as to be integral with the latter in rotation. .

  The starter 10 also comprises an electromagnetic contactor 62, of general design known in the field of motor vehicle starters, including a movable magnetic core 64, whose displacements are caused by a coaxial annular winding or winding 65 of axis X2 parallel to the X1 axis, control the axial displacement of the moving assembly 28 by means of a lever 66 which is pivotally mounted about an intermediate axis Y orthogonal axes X1 and X2.

  The movable core 64 acts on the upper end 68 of the lever 66 as it moves rearwardly through the solenoid 65 so as to cause a corresponding axial movement back and forth from the lower end 70 lever which is here shaped fork to act on the moving assembly 28.

  The contactor 62 is energized to cause both the axial displacement of the moving assembly 28 forward and the starting of the electric motor 16.

  The electric motor 16 rotates the armature shaft 14. The latter transmits this rotational movement to the output shaft 12 via the two consecutive reducers 19 and 18.

  The casing or housing 48 houses all the components of the starter which, for driving a heat engine (not shown), comprises a grooved pulley 80 which is here arranged outside the housing 48, and which is coaxial X1 axis with the drive shaft 12 whose front end portion 22 is guided in rotation by the pulley 80 with the interposition of a front ball bearing 82 arranged inside the axial bore 84 which passes through the tubular body 86 of the pulley 80 whose front section is grooved externally 88 to receive a belt 89.

  The rear portion 90 of the body 86 of the pulley 80 is of reduced diameter and is rotatably mounted in the housing or housing 48 through a rear ball bearing 92 which is received in a concave housing 94 formed in a housing. tubular front end 96 of a front element 200 of the casing or housing 48 which serves as a support including the contactor 62 and the motor unit consisting of the electric motor itself and its two reducers 18 and 19.

  The housing housing the engine block is immobilized in rotation in a known manner, for example by means of axial pins not shown, and the axial assembly is achieved by means of axial clamping screws 202.

  The design of the pulley 80 and the bearings 82 and 92 is such that the pulley 80 is axially fixed relative to the casing 48 along the axis X1.

  The starter 10 thus comprises, from rear to front, an axial stack, of axis X1, consisting of the electric motor 16 with its armature shaft 14, the two consecutive reducers 19 and 18, the moving element 28 with freewheeling 30 and the output pulley 80.

  The freewheel 30 forms the movable axial assembly 28 with its stepped tubular rear part and the front pinion 32 between which the rolling elements 29 of the freewheel 30 are interposed.

  The fork 70 of the lever 66 acts on the rear face of the stepped portion which, in its rear axial position of rest shown in FIG. 1, is axially supported by its rear annular axial end against a washer which bears axially towards the rear against an outer radial shoulder of the output shaft 12 which thus constitutes a rear stop of rest.

  The axial displacement towards the front of the moving element 28 with its front pinion 32 is limited by a forward axial stop 110 which is here a rod mounted on the shaft 12 by a resilient ring 112 mounted in a groove 116 of the tree 12.

  To constitute a controlled coupling mechanism in rotation, or clutch, with the pinion gear 32, the rear portion 90 of the inner bore 84 of the axially fixed pulley 80 is toothed internally with a group of teeth to form a ring gear internally. 118 in which the pinion 32 with its complementary teeth 120 can penetrate axially from rear to front under the action of the force applied to the moving element 28 by the fork 70.

  Thanks to the coupling mechanism 32-118, it is possible to separate the rotating pulley from the freewheel 30, and therefore from the drive shaft 12, which therefore does not operate continuously during very long periods of operation. and in a very restrictive environment such as that of a heat engine.

  The pinion gear 32 of the freewheel has teeth 120.

  The teeth 118 of the ring gear of the pulley 80 are complementary to the teeth 120.

  When the power supply of the linear actuator that constitutes the switch 62 is cut off, the return spring 67 of the movable core 64 recalls the moving element 28, via the lever 66, axially towards the rear against the stop back rest.

  When the combustion engine is started, the pulley 80 is continuously rotated at a speed of between 2,000 and 18,000 rpm, which is a function of the rotational speed of the engine, and the drive ratio between the crank pulley and the crankshaft. pulley 80 of the starter 10.

  When the clutch clutch 32, 118 is disengaged, only the pulley 80 and the bearings 82 and 92 rotate continuously. The other coaxial components of the starter 10 are not rotated.

  However, as explained in the preamble, the pulley 80 rotates continuously under the action of the belt 89, and the various bearing bearings are subjected to very large loads.

  According to the teachings of the invention, and as can be seen in particular in Figures 2 and 3, the free end 22 of the output shaft 12, which rotates from the pulley 80, no longer extends outside cantilever.

  Indeed, the front 200 support member belonging to the housing 48, comprises an arm 206 which extends generally axially forwardly.

  The arm 206 comprises a first horizontal axial branch 208 which extends from a front transverse face 201 of the support element 200, and which is extended by a second vertical radial branch 210, with advantageously a reinforcement rib 212 which extends in a vertical plane passing through the axis X1.

  The upper free end of the vertical leg 210 comprises a sleeve or sleeve 214, of large axis X1, which internally delimits a blind bore 216 which rotatably receives the free end 23 of the front end portion 22 of the output shaft 12, with radial interposition of rolling elements which are here constituted by needles.

  Thus, the front end section 22 of the output shaft 12 is perfectly guided in rotation and carried by the arm 206.

  The front section 22-23 extends axially through the stepped tubular body of the pulley 80, the latter being rotatably mounted on the section 22 by means of a pair of adjacent ball bearings 82, similar to the bearing. ball 82 of Figure 1.

  The pair of bearings 82 further ensures the axial immobilization of the pulley 80 relative to the shaft 12-22, and therefore relative to the housing 48200-201.

  The other components of the starter system 10 are similar to those described above with reference to FIG. 1, and in particular with regard to the moving element 28 and the rotational coupling means formed by the pinion 32 with its teeth 120. , and the ring gear arranged at the rear axial end 90 of the body of the pulley 80, with its teeth 118 complementary to the teeth 120 of the pinion 32.

  As can be seen in particular in Figure 3, the arm 206 which supports the free end 22-23 of the output shaft 12 provides no hindrance to the path of the belt 89, nor to its mounting on the pulley 80 .

  Indeed, the arm 206 is dimensioned, with its two branches 208 and 210 and its reinforcing rib 212, so as to extend in a generally vertical plane below the pulley 80, considering FIGS. 2 and 3 and FIG. with a reduced transverse bulk (or thickness), which allows the two vertically oriented strands of the belt 89, on either side of the pulley 80, to be very close to one another.

  As can be seen in Figure 3, it is also possible to arrange a tensioner roller 218 whose large axis X3 is parallel to the axes X1 and X2.

  According to a known technology, the tensioning roller 218 can be manually or automatically adjustable and is integrated in the starter system 10 very easily because it can also be fixed or mounted in an adjustable manner on the support member 200.

  Thus, the winding angle of the belt 89 on the pulley is particularly important, thus enabling high stresses to be transmitted to the belt 89.

  The attachment means of the contactor 62 and the electric motor 16 on the support element 200, completed by the arm 206, are similar to those described above with reference to FIG. 1, in particular by cylindrical interlockings and fixing screws. of axial orientation such as the screws 202, completed by unrepresented centering pins of orientation parallel to the general axis of the system 10 and which make it possible in particular to angularly orient the components 16 and 62 with respect to the support 200.

  According to the second embodiment of the invention illustrated in FIG. 4, the front free end section 22 of the output shaft 12, and more particularly its free front end 23 and received, is guided in rotation in a blind bore 216 (with for example interposition of needles), which is formed in a sleeve or fixed sleeve 214 which is attached to the upper free end 5 of the vertical and radial branch 210 of the arm 206.

  For this purpose, the sleeve 214 extends axially forwardly by a cylindrical massive body 222 forming a hub which itself comprises a threaded front tail 224 which is mounted screwed and axially clamped in a tapping 226 of the branch 210.

  The blind bore 216 is thus formed in a rigid insert element 222 which, on the other hand, serves as a support for the crazy rotational mounting of the pulley 80 whose tubular body 86 is rotatably mounted on the cylindrical solid body 222 through a pair of ball bearings 82 which also ensure the axial immobilization of the pulley 80.

  The body 222 thus acts as a hub for the pulley 80 as well as for the free end 23 of the front end section 22 of the output shaft 12, the axial position towards the front of the latter relative to the hub. 222 being determined by its coming axial bearing forward against a ball 228 arranged in the blind bottom of the bore 216.

  It is possible to replace the needles by a self-lubricating bearing ring 218 since the only radial load at this level is the weight of the moving assembly 28, and in particular of the disengageable coupling mechanism 32-120 with its wheel. free 30.

  Furthermore, the fixed axial positioning of the pulley 80 with respect to the starting system 10, and in particular with respect to the support element 200-201, and much more precise than previously insofar as all the machining operations which determine this Axial position belong to arm 206-210 and hub 222.

  According to the first two embodiments of the invention which have just been described, the arm 206 is made integrally in one piece with the support element 200.

  However, in some cases, and particularly when the starter system is used in conjunction with a high displacement diesel engine which requires greater training efforts for its starting, the resistance to the forces (and especially to the bending in a vertical and axial plane) of the one-piece arm 206 may be insufficient, in particular because its transverse thickness is even smaller than the winding angle of the belt 89 around the pulley 80 is big.

  In this case, it may be necessary to use the solution according to the third embodiment shown in FIG. 5.

  In this embodiment, the arm 206 is made in the form of an insert on the support element 200, 201 and is particularly rigid insofar as, on the one hand, it can be made of thick sheet metal. cut and folded and, on the other hand, it comprises a third upper branch of axial and horizontal orientation 230 which extends axially rearwards from the upper end of the vertical branch 210.

  The arm 206 thus has a generally U-coated shape, the two horizontal parallel branches 208, 230 of which are fixed rigidly to the support element 200 by screws 232 and 234, respectively, which extend in a transverse direction, and by corresponding tightening nuts.

  As can be seen in FIG. 5, the arm 206 with its upper supplementary limb 230 then passes over the pulley 80 and the corresponding wound strand of the belt 89.

  Thus, the winding angle of the belt 89 around the pulley 80 is almost complete.

  The screws or studs 232, 234 may be constituted by screws or studs which are implanted in the engine block of the engine for mounting and fixing the starter system 10 and which pass through holes or arm lights, the tightening nuts being then doubled as shown in Figure 5 so as to allow mounting and independent clamping arms.

  The assembly and assembly operations of the system 10 can then be carried out in the following order: - mounting and preliminary fixing of the starting system on the heat engine, without the arm 206; - Set up the belt 89 on the pulley 80 - mounting the arm 206 and fixing thereof, after axial engagement of the free end 22-23 of the output shaft 12 15 in the corresponding blind bore. For this purpose, the horizontal branches 208 and 230 comprises horizontal lights or buttonholes not shown.

  This design also facilitates maintenance and repair operations, especially that of changing the belt 89 because it then becomes only necessary to disassemble the arm 206, the entire starter system 10, with its wiring and electrical connections. , remaining attached to the engine block.

  One of the advantages of the invention according to the various embodiments which have just been described lies in the fact that, thanks to the presence of the arm 206 which supports the free end of the shaft, it is possible to accommodating the guide bearings of the pulley 80 on the opposite side to the electric motor 16. As a result, the rear end portion of the pulley 80 is free and it is therefore possible to use it, in accordance with the embodiment of Figure 6, to arrange or integrate the free wheel 30.

  For this purpose, the rear tubular section 90 no longer has a ring gear, as before, but delimits radially outwardly a housing 236 which in particular receives the elements 29 of the freewheel 30 and all the other known components necessary for operation a freewheel classic.

  The radially inner ring 238 of the free wheel 30 is internally toothed with a series of teeth 118 so, in association with the teeth 120 of the pinion 32, to constitute the coupling mechanism of the jaw type to rotate the shaft output 12-34 with pulley 80.

  The moving element 28 is no longer constituted only by the pinion 32 which extends axially rearwardly by a tubular body 33 which allows the axial displacement of the pinion 32 to be controlled by means of the fork of the lever 66.

  The freewheel 30 integrated in the pulley 80 is closed axially rearwards by a plate 240 of radial orientation which belongs to a cover 242 which axially covers the rear tubular section 90 of the body of the pulley 80.

  It is thus possible to house lubricant in the free wheel to ensure the reliability and longevity of the free wheel mechanism.

  To prevent loss of the lubricant, especially by centrifugation, it is possible interposed a seal.

  With this embodiment, the starting system is more compact axially.

  In addition, in comparison with the previous embodiments, the mass of the moving element 28 is very small, which makes it possible to use a contactor 62 of smaller dimensions, which further contributes to a greater compactness of the system. starting 10 and a reduction in its total weight.

Claims (16)

  1. Starting system (10) for driving a motor vehicle engine by means of a belt (89) and at least one pulley (80) driven in rotation by an electric motor ( 16), of the type in which the pulley (80): - is rotatably mounted on a section (22, 222) of a shaft which extends axially inside the pulley (80); and - extends axially forward, at least in part, outside a support element (200), characterized in that the free front end (23, 224) of the shaft section ( 22, 222) is carried by an arm (206) integral with the support member (200).   2. System according to the preceding claim, characterized in that the arm (206) comprises at least one first leg (208) which extends axially forwardly from the support member (200) and which is extended by a second branch (210) of radial orientation which carries said forward free end (23, 224) of the shaft section (22, 222).   3. System according to one of claims 1 or 2, characterized in that the arm (206) is formed in one piece with the support member (200).   4. System according to one of claims 1 or 2,   characterized in that the arm (206) is an insert on the support member (200).   5. System according to any one of the preceding claims, characterized in that said free front end (23) of the shaft portion (22) is rotatably mounted in a bore (216) of the arm (206, 210, 214). , and in that said shaft portion (22) is the front end portion of a drive shaft (12) rotatably connected to the armature shaft (14) of the electric motor (16) .   6. System according to the preceding claim, characterized in that said bore (216) is a blind bore in which said free end (23) of the shaft portion (22) is rotatably mounted with the interposition of rolling elements ( 218), especially needles.   7. System according to any one of claims 1 to 4, characterized in that said free front end (224) of the shaft section (222) is fixed on the arm (206, 210, 226), and in that said shaft section (222) rotatably receives the front end portion (22, 23) of a drive shaft (12) rotatably connected to the armature shaft (14) of the electric motor ( 16).   8. System according to the preceding claim, characterized in that said free end (224) of the shaft portion (222) is mounted screwed into a threaded bore (226) of the arm (206, 210).   9. System according to any one of claims 5 to 8, characterized in that said drive shaft (12) is connected to the armature shaft (14) of the electric motor (16) via at least one speed reducer (18, 19), in particular of the epicyclic gear type.   10. System according to any one of claims 5 to 9, characterized in that a free wheel (30) is interposed in the kinematic chain between the armature shaft (14) of the electric motor (16) and pulley. (80).   11. System according to the preceding claim, characterized in that the free wheel (30) is mounted axially movable relative to the pulley (80) fixed axially.   12. System according to the preceding claim, characterized in that the free wheel (30) is slidably mounted axially on a splined section (34) of the drive shaft (12).   13. System according to claim 10, characterized in that the freewheel is integrated in the body (90) of the axially fixed pulley (80).   14. System according to any one of claims 5 to 13, characterized in that the pulley (80), axially fixed, is rotatably connected to a coaxial element (118) of movement output which belongs to a mechanism (32- 120, 118) and which is rotatable with a movement input member (32) of the coupling mechanism (32, 118) which is rotatably connected to said shaft (12). ) connected in rotation with the armature shaft (14) of the electric motor (16), and that there are provided means (62, 66) for controlling the coupling mechanism (32). 120, 118).   15. System according to the preceding claim, characterized in that said control means are capable of axially displacing one (32) of the two elements of the coupling mechanism (32, 118) relative to the other (118). to an active position to temporarily cause their coupling and thus link the pulley (80) in rotation with the drive shaft (12).   16. System according to claim 4, characterized in that the arm comprises at least one hole or a light for the passage of a screw or a stud for fixing the starter system, in particular on the engine block. a heat engine.