FR2929365A1 - Self braking differential for motor vehicle, has multi-disk friction element arranged between two coaxial side gear outlet shafts and case, and integrated with case and shaft using splines - Google Patents

Abstract

The differential has a case (1) rotating on two bearings (2, 3) driven by a conical or cylindrical toothed crown (5) of a flange (6) carrying a bearing (4). Two coaxial side gear outlet shafts (7, 8) rotate on bores in the case and the flange. Satellites pinions rotate on an axle (10) integrated with the case. A multi-disk friction element is arranged between the shaft and the case and is integrated with the case and the shaft using splines.

Description

The present invention relates to a differential with output shafts creating a torque of greater force than the resisting torque.

The differentials consist of gears that transmit to a rotating shaft, a movement of speed equivalent to the source or the difference of the speeds of the other two movements. More particularly, it is a transmission mechanism of the engine torque to the drive wheels which allows these wheels to rotate at different speeds in turns.

In this invention, this characteristic is obtained by a friction torque produced between two components rotating at different speeds in contact by surfaces subjected to an axial force generated by inclined ramps transmitting a torque between two components rotating at the same speed. The components linked by the friction torque are a sun gear and either the differential housing or the other sun gear. The inclined ramps may be teeth that rotate the satellites and planetary gears. They may be specially designed two-component binder teeth. It follows from the principle of generating the force exerted on the friction surfaces that the friction torque is proportional to the torque transmitted by the differential. This torque is called self-braking torque.

The friction surfaces may be specially configured or multiplied in successive multi-disk friction elements to provide the desired frictional torque. The number of disks is an adjustment parameter of the characteristics of the friction element, as well as the pressure angle of the ramps generating the working force.

An active element, external to the differential can be implemented to increase, if necessary, depending on the circumstances, the force exerted on the friction surfaces and thereby the degree of self-braking.30 The auto-braking function can be produced either by the differential itself by its internal components, or by a separate mechanism, specific, arranged on one or both output trees.

Figures 1 to 4 of plate 1/7 show the differential in its simplest version with external elements to increase the degree of self-braking.

Figures 5 to 13 of the boards 2/7, 3/7 and 4/7 represent other cases in which only the force generated by meshing satellites - planetary is used to compress the friction surfaces.

Figures 14 to 22 of the boards 5/7 and 6/7 show cases in which there is a pair of components connected by a coupling gear generating the working force.

Figure 23 of the board 7/7 shows a separate mechanism, embedded on a conventional differential ensuring self-braking.

Figures 1 to 4 of Plate 1/7 show the basic differential of the invention. It is a bevel gear differential, consisting externally of a main housing (1) containing the mechanism, rotating on two bearings (2 and 3), driven by the crown (5) closed by the flange (6). which possibly comprises the replacement bearing (4) (3) and internally two planetary output shafts (7 and 8) meshing with the satellites (9), which rotate on the axis (10) integral with (1).

On the upper part of Figure 1 on the left, the sun gear (8) has on its large diameter, opposite to its teeth, a spherical range coincides with that used to support the satellites. If a is the average angle that the spherical bearing 30 makes with the differential axis, the friction torque is increased in the ratio 1 / cos a.

On the upper part of FIG. 1 (7) comprises a fluted bearing on which is fitted the flange (11) interposed between (6) and (7). (11) has a rim surrounding the outside of (7) whose outer spherical or conical shape is supported on a conjugate form made on (6). A washer (12) inserted between (7) and (11) of thickness e selected mounting, adjusts the meshing game satellites (9) with the sun gear (7). The average pressure angle that the generatrix of the sphere or cone with the axis of (7) increases the useful force in the ratio 1 / cos a. This angle has, associated with the pressure angle b of the meshing gear, a force adjustment parameter.

In the lower part of FIG. 1, a friction element (17) consists of a pair of disks fitted by means of splines, one on the sun gear (7a), the other on the housing (1). bis), interposed between (7a) and the flange (6a) and which triples the friction torque acting on (7) relative to (1). The discs can be multiplied at will to obtain the desired friction torque. They can be assembled in a single element as shown or be distributed between two elements, the other of which is: disposed on the opposite planetary output shaft (8). This solution is not represented.

On the upper part of Figure 1 is shown, fixed on the housing of the differential, an electromagnet (13). It is implanted coaxially with the output shaft (7) and at a gap distance of the plate (14) secured to (7) by the annular nut (15) screwed in the axis of (14) and forcing it on two half-conical rings (16) inserted in a groove made on (7).

The electromagnet (13) when energized attracts the plate (14) which exerts a complementary force on the internal friction surfaces producing the self-braking. The powering on is triggered according to the circumstances automatically or not, the value of the voltage of the same.30 On the lower part of Figure 1 is shown a rotating stop board on the output shaft (7). The latter (18) abuts on the elastic ring (19) inserted in a groove made on (7a). The outer ring is fitted into a plate (20) on which the additional force can be exerted by an external actuator, not shown, which is controlled as (13).

FIG. 2 shows two meshing gears between satellites (9) and planetary gears (7 and 8). On the left, a standard toothing with a pressure angle b of 20 degrees, on the right, a toothing with a pressure angle of 45 degrees.

The increase in the effective force for an identical tangent effort is 2.5 (relative to tangents b). The angle b is a force adjustment parameter.

The different versions or options shown in FIGS. 1 and 2 are independent of one another. In order to balance the forces exerted externally on the differential, the active elements (13) and (20) can be duplicated symmetrically on each of the output shafts.

FIGS. 3 and 4 show, in addition to FIG. 1, a jumper having: as a function of securing the satellite axis of the main housing. The latter (21) consists of a parallelepipedal portion (22) terminated by ramps (23), a flexible arch (24) terminated by a lug (25). The portion (22) is inserted on the protruding portion of (10) in a notch perpendicular to the axis, against a shoulder (26) of the housing (1). (23) and (25) facilitate placement. (24) is forced on (10) and holds (21) in place. The radial interface between (21) and (1) may be flat or cylindrical. Two jumpers, under the conditions described are necessary to fully secure (10) of (1). Alternatively, an axial groove (27) may be provided on (1) together with (10), the portion (22). In this case, only one jumper is needed.

Figure 5 of Plate 2/7 shows a connection of the friction element to the housing via the satellite axis. The latter (10) is fitted into the radial bore of a hub disk (31) which has an axial grooved tail (32) passing through the sun gear (33) and which is connected to the inside of the friction element. (17). (33) has a splined skirt internally bonded to the outside of the friction element (17) and the output shaft (34) by its head (35). The upper part of Figure 5 corresponds to the case of two satellites.

The lower part of FIG. 5 corresponds to the case of a number of satellites that can be greater than two. A satellite gate (36) has a hub (37) and a fluted tail (38) similar to (32) and the same function. The drive (36) is performed by the arms (39) on the end of which is fixed by a screw (41), a nut (40) on the left, or (40) on the right, fitted in a radial bore of the housing. The nut (40) provides only the drive of (39) and the satellite (42) is supported on a spherical bearing of the housing. The nut (40 bis) further provides radial plane support of the satellite (42 bis).

Figure 6 of the board 3/7 upper part shows the drive of a satellite gate brace (45) with the cylindrical protruding ends of its arms (46). These are engaged in radial bores (47) shared between the housing 20 (1) and the sleeve (48) symmetrically to their axis. (45) may comprise a fluted tail (49) identical to (32) and (38) and of the same function.

Figure 6 below and 8 show a variant in which the protruding ends of the arms (46 bis) of the spider (45 bis) are cut in tenons engaged in notches (47 bis) made on the skirt of the flange (52) wearing the crown (5). The mechanism is closed by the open housing (57) through which the torque does not pass.

The planetary output shaft (55) is extended by a fluted shank (56) extending through the hub (45) and the sun gear (58), which terminates as (32), (38) or (49) and is engaged in the friction element (17) which links the two output shafts (55) 5 and (34). A doubled degree of self-braking is obtained with respect to the solution of binding an output shaft to the housing due to the ratio of speeds between (34; 1 and (55).

Figures 9 and 10 of the board 3/7 show a direct drive by splines of the satellite carrier (61) by the housing (62). (61) comprises arms or sectors (63) grooved on their periphery and nested in mating surfaces made on (62). The satellite carrier arms (64) are cantilevered on (61). Lei, spherical support bearings of the satellites can be machined by internal counterbore.

Figures 11 and 12 of the board 4/7 represent the means of accumulate sui single friction element, the axial reactions of the two planetary and thus double the self-braking effect. The sun gear (71) comprises a fluted skirt driving the output shaft (72) by its head (73), (73) having on its face opposite to (71), on a median radius an annular boss. (74) on which support the arms of a diaphragm (75) whose outer ends receive the thrust of (71) and that the inner ends return to the friction surfaces.

On the upper parts of Figures 11 and 12, said thrust is transmitted through, successively, the fluted nut (76) sliding in (71), stirrups (77) bypassing the axis of satellites (78) to the right two flats (79) and finally the sun gear (8). (8) in the figure directly on the flange (6) but it could naturally be interposed a friction element.

In the lower parts of FIGS. 11 and 12, the diaphragm (75) is replaced by a set of crooked lever (81) trapped in semicircular bottom radial housings made on the front face of the head (73a). ) of the output shaft (72a). The levers (81) receive at their outer end the thrust of the sun gear (71 bis) and return it by their inner end to the friction surfaces, here the friction element (17) via the axis (85) sliding in the grooves (71a) and having at the other end a plate (86) pushing (17) against the head (35) of the output shaft (34), and a fluted tail (87) bound inside (17). (17) is externally linked to the sun gear (8a) having a fluted skirt.

Figure 13 of the board 4/7 shows an asymmetrical differential that can be integrated into the transmission of a vehicle, between two pairs of drive wheels requiring different driving torque justified by loads, unequally distributed.

The upper part of the figure represents the case of a sun gear linked directly to the housing. The lower part the case in which the two planetary are linked.

The planetary left (91) and right (92) have a number of teeth in the ratio of couples to transmit. The satellites are embedded on a planet-carrier cross, the axes of the arms of which are arranged on the median cone of the teeth (91) and (92). The arms are driven by their protruding end cut in tenon by the skirt of the flange (95) which comprises the spherical bearing surface of the satellites and the driving notches. The configuration is identical to that of the figure (6) lower part to the angle near the satellite axes.

Figures 14 to 16 of plate 5/7 represent the first of the cases in which a specific toothing is created to generate the force exerted on the friction surfaces. The flange (115) carrying the drive ring, comprises a skirt which directly drives the satellite gate brace (117) by a toothing (116). (117) comprises arms or sectors (118) cut relative to (116) in a conjugate toothing. The flanks of the teeth can be machined according to a plane, a helicoid or involute of a circle. If the helicoid is the ideal of the practical considerations militate in favor of the involante. Indeed, the teeth can be machined on conventional machines for cutting bevel gears, such as a flat wheel. The pressure angle b determines, for a given tangential effort, the value of the useful axial component. It is a setting parameter of the degree of self-braking. (117) transmits the thrust received from (116) by the face (122) of its hub in contact with the sun gear (33) (upper part) or (8) (lower part).

In the lower part of FIG. 15, the sun gear (8) bears directly on the bottom of the casing (57) but a friction element can be interposed.

On the upper part of Figure 15, the sun gear (33) is connected to the output shaft (55) by the friction element (17) the satellite carrier arms (119) are false door. The satellites (120) are supported on washers (121) indexed on the end of the arms (119) cut for this purpose tenon and, marrying, outside the cylindrical shape of the bore of (57) and to inside, the flat bearing face of (120).

Figures 17 to 20 of the board 6/7 show the case in which the specific toothing 15 generating the useful effort is made on a housing or cage door intermediate satellites.

In the lower part of FIGS. 17 and 18, the flange (115) drives, through its toothing (116), the open intermediate planet carrier (103) which has a bottom (104) bearing on the friction element (17). pressed on the bottom of the housing (57) and a fluted skirt (105) bound to the outside of the friction element (17). The case corresponds to two satellites.

At the top of FIG. 17, 19 and 20, (103) is replaced by an annular gate (111) which transmits the useful force generated by (116) to the satellite gate (107) by the end. protruding from its arms (108) cut flattened tenon by its notches conjugate according to Figure 19. Alternatively, the thrust can be transmitted and the tangent force by the semi cylindrical bottom of the notch on the cylindrical end arm (108) according to figure 20. the thrust is transmitted to the friction surfaces by the face (109) of the hub (107). The friction element (17) is arranged according to previously described variants.

Figures 21 and 22 of the board 6/7 show a specific toothing generating the useful force interposed between a sun gear and its corresponding output shaft.

On the upper part of FIG. 21, the sun gear (125) has a face gear (126) of the kind (116) opposite to its meshing gear and nested in a conjugate toothing made on the head (128) of the output shaft (127). (125) is supported axially on the hub disc (129) which is supported on the sun gear (8) which bears on the bottom of the housing (1a). The friction element. (17) is interposed between (128) and the flange (6), and internally bonded to (127) and externally to (1a).

On the lower part of. 21, the friction element (17) is disposed inside the grooved skirt of the sun gear (131) subjected to the thrust of an intermediate disk (132) which is connected to the output shaft (128). bis). As an alternative to the toothing (126) is shown a ring of balls (133) coupling. These are trapped between (132) and (128 bis) in conical cells whose cone contact angle b determines the useful axial force compressing the friction surfaces. The other provisions correspond to descriptions already made.

Figure 23 of the board 7/7 shows a housing containing a mechanism ensuring the self-braking function and reported on a conventional differential that can remain standard. Only the flange (14) bearing or not bearing is specific. It comprises a splined hub and threaded on which is fixed by the nut (149) the housing (147). The planetary output shaft (140) exiting the differential has at its emerging end a corrugated seat nested in, successively, the inside of the friction element (17) and the disc (142). (142) has on the right side a coupling face toothing in which is engaged a conjugate toothing made with the head (145) of the true output shaft (144) guided in a bore of the flange (148) fixed on (147) . The coupling gear, transmitting the torque from (140) to (144), moves away from each other (142) and (145). (142) presses the friction element (17) against a shoulder (147) to which its exterior is bonded. (145) is pressed against the flange (148). From these two actions results self-braking. A lid (148) closes (147). The seal (150) is carried by the housing (151) fixed to the differential housing. 10 15 20 25 30

Claims (1)

Claims 1: Self-braking differential characterized in that a sun gear (7 or (8) bears, to withstand the axial force resulting from its meshing with the satellites, on a spherical or conical rubbing surface. surface may be the same as that used to support the satellites Flange side (6) closing the housing, the friction surface may be carried on a friction element consisting of a flange (11) having a spherical or conical bearing, secured of the sun gear (7) by splines The adjustment parameters of the self-braking torque are the pressure angles α of the friction surface and b of the gear teeth Claim 2: Self-braking differential according to Claim 1 characterized in that the friction element consists of discs secured by means of internal and external splines, alternately, sun gear (7a) and housing (1a). Self-locking frame according to Claims 1 and 2, characterized in that an output shaft (7) receives a plate (14) rotating at an air gap distance from an electromagnet (13) external to the differential, making it possible to increase depending on the circumstances the force exerted on the friction surfaces by energizing the electromagnet. Claim 4: Self-braking differential according to Claim 1, characterized in that the axis of the satellites (10) is secured to the housing (1) by means of a jumper (21) consisting of a parallelepipedal portion (22) terminated by ramps. (23), a flexible arch (24) terminated by a lug (25), the portion (22) is inserted on the protruding portion in a notch perpendicular to the axis, against a shoulder (26) of the housing (1). ), the lug (25), the jumper (21) in place, in these conditions secures the axis of the satellites (10) with the housing (1). Claim 5: Self-braking differential according to Claim 1, characterized in that the sun gear (33) has an internally splined skirt bound to the outside of the friction element (17) and to the head (35) of the output shaft. (34), (17) being interposed between (33) and (35), the interior of (17) being connected to the fluted tail (32) therethrough (33) and part of the hub disc (31) traversed by the satellite axis (10). Claim 6: Self-braking differential according to Claim 1, characterized in that a satellite gate (36) comprises a hub (37) and a fluted tail (38) similar to (32) with a drive carried out by the arms (39) receiving , fixed by means of a screw (41), a nut (40) on the left, fitted in a radial bore of the housing (40 bis) can, on the right, ensure the radial support of the satellite (42 bis). Claim 7: Self-braking differential according to Claim 1, characterized in that the sun gear (55) comprises a fluted shank (56) crossing in its axis the spider (45a) and the sun gear (58), bound to the interior of the friction element (17), the outside of which is connected to the sun gear (58). Claim 8: Self-braking differential according to Claim 1, characterized in that a satellite gate brace (45) is driven by the cylindrical protruding ends of its arms (46) engaged in radial bores shared between the housing (1) and the sheath. (48) symmetrically to their axis, (48) being interposed between the housing and the flange (6) closing it. Claim 9: Self-locking differential according to Claim 1, characterized in that the spider (45a) or (45b) is driven by the protruding ends of the arms (46a) or (46b) cut into tenons engaged in notches ( 47a) made on the skirt of the flange (52) or (95) carrying the ring (5), the arms (46a) being arranged on a plane, the arms (46b) being arranged on a cone. Claim 10: Self-braking differential according to Claim 1, characterized in that the means for accumulating on the friction element, the axial reactions of the two planetaries is obtained by a diaphragm (75) or a set of levers (81) taking support on the head (73) or (73 bis) of the output shaft (72) or (72a) and returning the thrust received from the sun gear (71) or (71a) on the sun gear (8) or (8a) by the intermediate sliding elements (76) (77) (85) coaxial. Claim 11: self-locking differential according to claim 1 characterized by a flange (115) carrying the drive ring, comprises a skirt which directly drives the satellite gate brace (117) by means of a toothing (116) made on arms or sectors (118) cut relative to (116) according to a conjugate toothing. Claim 12: Self-braking differential according to Claim 1, characterized in that the flange (115) drives, by means of its toothing (116), either the open intermediate satellite carrier (103) which comprises a bottom (104) bearing on the element friction (17), or the annular cage (11) which transmits thrust via the spider (107). Claim 13: Self-braking differential according to Claim 1, characterized in that the sun gear (125) has a face toothing (126). opposed to its meshing gear, and which fits into a conjugate toothing made on the head (128) of the output shaft (127) which presses the friction element (17) against the flange (196). Claim 14: Self-braking differential according to Claim 1, characterized in that an intermediate disc (132) connected to the sun gear (131) drives the output shaft (128a) and compresses against the bottom of (131) the element of friction (17) internally linked to the sun gear (8a) extended by a fluted tail crossing the satellite prot. Claim 15: Self-braking differential according to Claim 1, characterized in that the toothing (126) is replaced by a ring of balls (133) trapped in conical cells made of. vis-à-vis the sun gear and the output shaft, possibly through a disc (132). Claim 16: Self-braking differential according to Claim 1, characterized in that the mechanism. self-braking device is contained in a housing (107) integral with a differential closing flange (141) and consisting of a disk (142) splinedly connected to the output shaft (140) driving through a set of teeth coupling the output shaft (144) by its head (145). (142) and (145) bear axially on (147) and the flange (148) closing (147), a friction element can be interposed between (142) and (147), respectively connected to (140) and (147). ).