GB2098286A - Hub clutch for use in vehicle four wheel drive - Google Patents

Abstract

Engagement hub 1, splined at 3 to axle end, is selectively clutched to drive wheel hub 9, by ring 16 which is toothed to slide in internal grooves in wheel hub 9, merely by engaging four wheel drive. The transmitted torque causing balls, engaging axial grooves in hub 1 and race 22, to be carried axially by a cage 27 having camming recesses. The resulting axial movement of race 22 being transmitted to ring 16 by biconical springs the ensuing leftward movement of ring 16 causing internal clutch teeth to engage with external clutch teeth of engagement hub 1. Wheel hub 9 is supported on the axle by an inwardly directed flange 8 engaging a bush (7) mounted on the hub 1. <IMAGE>

Description

SPECIFICATION Vehicle front wheel release device As is known to those skilled in the art, there exist vehicles which are equipped with four-wheel drive. This kind of drive can be provided with a mechanical device designed to release or allow for free-wheeling of the front wheels, which device is fitted to the hub of each vehicle front wheel, where it is solidary with the. traction shaft end and, as the very name implies, has the function of releasing the front wheels from the front wheel drive shaft system since the rotating movements of the front wheels, applied to the front wheel drive, are transmitted to the vehicle gearbox, as when the vehicle is set in motion, all components of the front wheel drive located between the gearbox and the wheels are also set in motion, independently from the fact that said front wheel drive is connected or not.

The utilization of the front wheel drive device in four-wheel drive vehicles allows for a considerable reduction in fuel consumption since a portion of the power generated by the engine will not be wasted in moving all those components of the front drive between the wheels and the vehicle gearbox when such drive need not be used.

There exist at present automatic and manual devices to release the front drive but the automatic ones have the disadvantage of not allowing for engine braking, while the manual ones have the inconveniency of requiring that one should leave the vehicle to lock or release the front drive which is not always feasible depending on the terrain conditions where the vehicle is moving.

The inconveniencies existing with the known systems are entirely eliminated with the present improvement, which consists of a free wheel that enables the vehicle to have motor braking effect and provides fully automatic locking and release, that is, it permits activation of the front drive through the gearbox auxiliary lever as is normally done inside the vehicle; upon which the free wheel is automatically engaged upon movement of the vehicle. In order to disengage the device it is sufficient to release the front wheel drive through said lever and then move the vehicle slightly in a direction contrary to that of its previous movement; upon this operation, the free wheel disengages itself. In this manner, there is fully automatic engagement and disengagement of the device, whether the traction is towards the front or the rear.

For a clear understanding of the present invention references will be made to the appended drawings, where figure 1 is a side view in longitudinal section of the device in the engaged and disengaged position, that is, starting from the centreline and downwards, a half section in the engaged position; the figures 2 and 2A illustrate the entire set in exploded perspective; the figures 3, 4, 4A illustrate the present invention according to a small alternative construction, figure 3 being a side view in longitudinal section of the device in engaged and disengaged position, that is, from the centreline and upwards in disengaged position, and from the centreline downwards in engaged position; and figures 4 and 4A illustrate the entire assembly in exploded view, according to the alternative embodiment.

The present Patent of Invention refers to-a vehicle front wheel release device which, according to one first constructive embodiment (figures 1, 2 and 2A) is composed of a cylindrical, internally grooved engagement hub (1) which is coupled to the externally grooved end of the traction shaft (2) of the vehicle front drive transmission system, while the end of said hub (1) is provided with a pair of properly spaced apart annular grooves (4) to receive a lock ring (5) and two sliding rings (6) between which is located a bushing (7); and between ring (6) and said bushing (7) is a diametral constriction (8) which projects normal to the inner diameter and the free end of the body (9) which configurates a support for the entire assembly; the free end of which body is closed by a cap (10) provided with a seal ring (11) fixed by bolts, while the opposite end is provided with orifices (12) through which the same is fixed to the outer assembly (13) of the vehicle wheel hub.

Adjacent to the inner lock ring (5) the engaging hub (1) has a narrow toothed section (14) followed by a smooth section (1 5) both of which determine the "engaged/disengaged" positions, since therein works a ring (16) which establishes engagement between the traction shaft (3) and body (9); to that effect, said engagement ring (16) has a stitched inner surface (17) and the outer surface provided with lock teeth (18) which teeth coincide with the toothed section (14) of hub (1) while the lock teeth (18) coincide with the longitudinal grooves (19) provided inside the body (9) where an expansion spring (20) is provided which has an end supported in diametral constriction (8) while the other actuates said lock ring (16) which in turn has the outer teeth (18) drilled by orifice to lodge the rivets (21) which attach a set of biconical springs (21'), the ends of which are attached to the actuating disk (22), which has an outer diameter equal to that of the lock ring (1 6), the inner face of which configurates a racetrack (23) for balls (24) which also slide in longitudinal grooves (25) arranged in said engagement hub (1); and between the actuating disk (22) and the engagement hub (1) there is a cylindrical section (26) of a "cage" (27), a section provided with directional slots (cams) (28) basically in a "V" shape through which the balls (24) maintain the actuating disk (22) slidably interconnected with hub (1).Said "cage" (27) has the front end of the cylindrical section (26) with a diameter slightly larger (29) which end, in addition to configurating an abutment wall for the lock ring (30) introduced in the annular channel (31) of hub (1), also configurates a recess for the sintered bushing (32) inside which is a slide (33) where a drag spring (34) slides with its ends turned inwards (35), adapted inside a slot (36) of a hexagonal drag nut (37) which in turn is threaded to the end of a fixed sleeve (38) inside which operates said traction shaft (3) of the front wheel drive system; drag nut (37) locked by counter nut (39) and safety ring (40) provided with outer radial vanes configurating a lock, while the inner diameter is provided with a vane capable of fitting inside a slot (41) in the outer face of the fixed sleeve (38).

Operation The shaft sleeve (38) is the only fixed part of the assembly, and appears as a differencing element whereby it is possible to identify which parts are moving, whether the shaft (3), the wheel hub (13) or both, because in said sleeve (38) is fixed the drag nut (37) in which slot (36) are fitted the ends (35) of the drag spring (34) which turns, offering a certain resistance inside the sintered bushing (32) which in turn is firmly pressed inside the "cage" (27).

The front drive device being in the "disengaged" position, the wheel hub turns freely, while the shaft (3) and the engagement hub {1) remain stationary (front drive disengaged).

In that position, the entire set of body (9)/actuating disk (22)/biconicai springs (21 ')/engagement ring (16)/ and return spring (20) also turns around the engagement hub (1) supported on the bushing (7) and the balls (24), said locking ring (1 6) turning in a "neutral" position, that is, its inner teeth (17) revolve on the smooth section (15) of hub (1).

In order to engage the device it is sufficient to turn the shaft (3) by actuating the front wheel drive as is normally done from inside the vehicle, upon which the engagement hub (1) revolves solidarily with the traction shaft (3) and the drag spring (34) offers resistance to the "cage" (27) revolving motion which causes the balls (24) to run towards one of the ends of grooves (25) of engagement hub (1) carried by the slots (cames) (28) provided on the "cage" (27). Said balls (24) move the actuating disk (23) to the engagement position and the biconical springs (21') overcome the resistance of the return spring (20) as soon as the inner grooves (17) of the locking ring (16) engages the teeth (14) and consequently the outer teeth (18) of said ring (16) are locked inside the body (9).In that position, the wheel releasing device is connected or locked to the traction shaft (2), that is, the body (9) is solidary with engagement hub (1) which is solidary with shaft (3) of the vehicle's front wheel drive, When the vehicle changes direction, the actuating disk (22) disengages and again engages ring (16) on hub (1) as the balls will move from one side to the other in the groove (came) (28) of "cage" (27) passing through the disengagement position, as shown on figure 2; theA and B ends of groove (28) correspond to the engagement position; balls (24) being in theA position, when the vehicle changes direction, the balls (24) will automatically leave position A and move towards position B (disengagement); in that position the lock ring (16) is on the smooth section (15) of hub (1); after the balls (24) reach position B; they continue their course until they reach position C on slot (28), where the device is again engaged, when teeth (17) of ring (16) engage teeth (14) of hub (1).

In order to disengage the device, it is sufficient to place the actuating lever on the appropriate positjon, disengaging the front wheel drive and move the vehicle in a direction opposite to its previous ride. The came (28) of "cage" (27) will make the balls move with actuator (22) from position A or C towards position B (disengaged) and with these the lock ring (16) is also displaced, disengaging the teeth (17) from teeth (14) of hub (1) not only by longitudinal movement of actuating disk (22) but also by expansion of the return spring (20) with which the shaft stops turning and fully releases the front wheels, as the return spring (20) maintains the locking ring (16) on the smooth section (15) of hub (1) and pressed against the "cage" (27) as long as shaft (3) is immobile.

In an alternative embodiment of said device, illustrated on figures 4 and 4A, the longitudinal grooves (25) of engagement hub (1) are eliminated, and replaced by an intermediate cage (42) of tubular shape, and to that purpose the engagement hub (3) after its toothed section (14) appears entirely smooth (43) and is provided at its end with a recessed step (44) followed by an annular groove (45) at the edge of which there is a locking outer recess (45); in that manner, said engagement hub (1) receives in its smooth section (43) said tubular cage (42) the penetration of which is limited by the annular projection (47) on the cage's inner face, which accurately fits on the step (44) of engagement hub (1); furthermore, said intermediate cage (42) is provided in its front end with diametral projections (48) located on opposite sides and on its wall with three oblong longitudinal openings (49) equally spaced apart inside which are located balls (50) maintained in position in the same manner as in the first embodiment, that is, by an actuating disk (22); and between the latter and the engagement hub (1), there is a cylindrical section (26) of an upper modified cage (27'), which section is provided with directional slots (cams) (28) basically'in a "V" shape through which balls (50) maintain the sliding actuating disk (22) mounted on engagement hub (1); and the front end of section (26) of cage (27') in addition to a diametral enlargement (29) is internally provided with a pair of radial projections (52) through which pass the points (48) of the intermediate cage (42), which points also oscillate inside slots (53) located in the inner side of an unlocking ring (54) which in its turn is solidary with the engagement hub (1) by means of an inner radial teeth (55) which in its turn fits to the external locking recession (46) of said hub (1) where the entire set is maintained by means of elastomeric ring (56) inside the annular groove (45) of said hub (1).

Inside the diametral enlargement (29) of upper cage (27') is assembled (see figure 4A) a set of clutches (57) composed of a reel (57') inside which is located an helical drag spring (58) the ends (58') of which are exposed and maintained supported against the ends formed by intersection (59) of the diametral enlargement wall (29) of upper cage (27'), and between the ends (58') of spring (58) is also end (60) projected normal to the outer edge of the unlocking ring (54).

As shown on figure 4A, the clutch set (57), through its inner thread (61) is assembled on fixed sleeve (38) inside which works said traction shaft (3) of the vehicle front wheel drive system; furthermore, on said fixed sleeve (38) is provided a keyway (62) to receive and lock an inner radial projection (63) of an intermediate washer (64) maintained between a counter-nut (65) and reel (57') which in turn is immobilized against rotating movement by means of bolts (66) with cemented ends which pass therethrough and are locked to the front face of said intermediate washer (64) since the latter cannot rotate due to the keyway that locks it to the sleeve (38).

As illustrated on figure 3, the stability of the assembly is achieved by bolt (67) threaded to the free end of said traction shaft (3) and therebetween are provided a pressure washer and a flat locking washer (68) the outer edge of which is supported by a recessing step (69) provided on the inner side of hub (1), maintaining it entirely immobilized against eventual longitudinal stresses.

Operation The operation of the device, according to the alternative embodiment, is similar to the first one, wherein the shaft sleeve (38) is the only fixed part of the assembly and appears as a differentiating element whereby it is possible to identify which parts are moving; whether the shaft (3), the wheel hub (13) or both; accordingly, there is attached to said fixed sleeve (38) the drag assembly (57) which spring (58) has its ends (58') fitted to the upper cage (27') to prevent the latter form revolving.

The front drive release device being in the disengaged position, the wheel hub (13) consequently rotates freely, while the shaft (3) and the engagement hub (1) are immobile (disengaged from drive). In that position, the entire assembly: body (9), actuating disk (22), biconical springs (21'), lock ring (16) and return spring (20) also rotate around the engagement hub (1) supported on bushing (7) and balls (50), while said lock ring (16) rotates in a "neutral" position, that is, its inner teeth (17) rotate on the smooth section (43).

In order to engage the device it is sufficient to rotate shaft (3), that is, to engage the front drive, as is normally done from inside the vehicle, upon which the engagement hub (1) rotates solidary to shaft (3); The drag spring (58) will prevent rotation of cage (27') when it is compressed against the clutch reel (57'), which causes balls (50) to move towards one of the ends of longitudinal grooves (49) in the cylindrical cage (42) carried by slots (cams) (28) provided in cage (27'). Accordingly, balls (50) carry actuating disk (22) towards the engagement position (as illustrated on figure 3) and biconical springs (21) overcome the resistance of the return spring (20) as soon as the inner grooves (17) engage teeth (14) and consequently the external teeth (18) of said ring (16) are locked inside the body (9).

In that position, the wheel releasing device is engaged or locked to the traction shaft (3), that is, body (9) is solidary with the engagement hub (1), which is solidary with shaft (3) of the vehicle's front wheel drive.

When the vehicle changes its sense of direction, the actuating disk (22) disengages and again engages rings (16) of hub (1) as balls (50) will pass from one to the other side of slot (cam) (28) of cage (27), passing through the disengagement position.

When the balls (50) reach the end of the longitudinal slots, which characterises the unlocking position, the end (60) of the unlocking ring (53) abuts the drag spring (58) releasing the pressure thereof against the clutch reel (57') causing the drag spring (58) to rotate against the clutch ring (44).

In order to disengage the device; it is sufficient to place the front drive actuating lever in the disengaged position, move the vehicle first in the first direction and then in the opposite direction (approximately 30 cm, in both directions). The Cam (28) of cage (27') will cause balls (50) to move along with actuating disk (22) from position A or C to position B (disengaged) and with these the lock ring (16) is also displaced, disconnecting its teeth (17) from teeth (14) of the engagement hub (1) not only by longitudinal movement of the actuating disk (22) but also by expansion of return spring (20) now facilitated by the movement permitted by cylindrical cage (42) on engagement hub (1) upon which shaft (3) stops rotating, leaving the front wheels entirely released, since that return spring (20) maintains the lock ring (1 6) on the smooth section (43) of the engagement hub (1) and pressed against cage (27), as long as shaft (3) is stationary.

As above explained, it is evident the great functional advantage of the object of the patent, as it eliminates the inconveniencies found in devices to release wheels of vehicles provided with automatic engagement, which automatically engage when the vehicle is accelerated but also automatically disengage when the vehicle is decelerated, that is, the usual automatic systems known have operated in a manner similar to the clutches actuated by bicycle pedals, while the object of this patent allows for automatic engagement as is usual, and that engagement remains even upon deceleration of the vehicle, the disengagement being performed only upon disengagement of the four-wheel drive mechanism provided on the vehicle.

Claims (7)

Claims

1. A vehicle front wheel release device on fourwheel drive vehicles composed of cylindrical engagement hub (1) provided with internal grooves (2) which couples to the grooved end of traction shaft (3) of the vehicle's front wheel drive system, characterized in that said hub (1) is provided with a pair of annular grooves (4) duly spaced apart to receive lock ring (5) and two sliding rings (6) between which is located a bushing (7) while between ring (6) and said bushing (7) is a diametral constriction (8) projecting normal to the inner diameter and the free end of a body (9) which configurates a support for the entire assembly.

2. A vehicle front wheel release device according to the previous claim, characterized in that adjacent to the inner lock ring (5) the engagement hub (1) is provided with a toothed section (14) followed by a smooth section (15), a lodgement for ring (16) for engagement between the traction shaft (3) and body (9); and to such purposes, said lock ring (16) has a grooved inner surface (17) and the outer surface is provided with lock teeth (18), inner teeth (17) engageable with the toothed section (14) of hub (1) while the lock teeth (1 8) are engageable with longitudinal grooves (19) provided inside the body (9) where is located an expansion spring (20) one end of which is supported on diametral constriction (9) while the other end actuates on said locking ring (16) which in its turn is provided with outer teeth (18) drilled by a hole for attachment of rivets (21) which fix a set of biconical springs (21') the ends of which are attached to the actuating disk (22) with external diameter equal to that of the lock ring (1 6), the inner face of which configurates a racetrack (23) for balls (24) which also slide in longitudinal slots (25) arranged in said engagement hub (1); while between the actuating disk (22) and the engagement hub (1) there is a cylindrical section (26) of a "cage" (27), which section is provided with directional slots (cams) (28) basically in "V" shape through which the balls (24) maintain the actuating disk (22) slidably interconnected to hub (1).

3. A vehicle front wheel release device according to the previous claim, characterized in that the "cage" (27) has the front end of the cylindrical section (26) with a slightly larger diameter (29) which configurates an abutment wall for lock ring (30) introduced in annular channel (31) of hub (1); also configurates a fitting for a sintered bushing (32) inside which is provided a slide (33) where a drag spring (34) slides with its ends turned inwards (35), fitted inside a slot (36) of an hexagonal drag nut (37) which in its turn is threaded to the end of a fixed sleeve (38) inside which operates the traction shaft (3) of the front wheel drive system; drag nut (37) duly locked and safety ring (40) provided with external radial vanes which configurate locking elements, while the inner surface is provided with a vane capable of fitting inside recession (41) on the outer face of fixed sleeve (38).

4. A vehicle front wheel release device where in an alternative embodiment of the device, and where the longitudinal grooves (26) of engagement hub (1) claimed in 2 have been eliminated, characterized in that they have been rep!aced by an intermediate cage (42) of tubular shape, and to that purpose the engagement hub (1) after the toothed section is entirely smooth (43) and is provided at the end with a recessed step (44) followed by an annular groove (45) in the edge of which there is an external lock recession (46), and said engagement hub (1) receives in its smooth section (43) said tubular cage (42) the penetration of which is limited by the annular projection (47) in the inner face of the cage, which fits on step (44) of the engagement hub (1); furthermore, said intermediate cage (42) is provided in its front end with diametral projections (48) located on opposite sides and on its wall with three longitudinal oblong openings (49) equally spaced apart inside which are located balls (50) maintained in position in the same manner as in the first embodiment, by an actuating disk (22); and between the latter and the engagement hub (1) there is a cylindrical section (26) of a modified upper cage (27'), which section is provided with directional slots (cams) (28) basically in a "V" shape through which balls (50) maintain actuating disk (22) slidably mounted on engagement hub (1), the front end of section (26) of cage (27') in addition to possessing a diametral enlargement (29) is internally provided with a pair of radial projections (51) opposite to each other, configurating slots (52) through which pass the ends (48) of intermediate cage (42), which ends also oscillate inside slots (53) located in the inner face of a disengagement ring (54) which in its turn is solidary with the engagement hub (1) by means of an inner radial tooth (55) which in its turn is fitted to the outer locking recession (46) of said hub (1) wherein the entire assembly is maintained, by means of elastomeric ring (56) inside annular groove (45) of said hub (1).

5. A vehicle front wheel release device according to claim 4, characterized in that inside the diametral enlargement (29) of upper cage (27') is assembled a clutch set (57) composed of a reel (57') inside which is located a helical drag spring (58) the ends of which (58') are exposed and maintained in support against the ends formed by intersection (59) of the diametral enlargement wall (29) of upper cage (27'), and between the ends (58') of spring (58) is further located an end (60) projected normal to the outer edge of the unlocking ring (54), the clutch set (57) through its inner thread (61) is assembled on fixed sleeve (38) inside which works said traction shaft (3) of the vehicle front wheel drive system; and further, in said fixed sleeve (38) is provided a keyway (62) to receive and lock an inner radial projection (63) of an intermediate washer (64) maintained between a counter-nut (65) and reel (57') which in its turn is immobilized against rotating movement by bolts (66) with cemented ends which pass therethrough and are attached to the front face of said intermediate washer (64) since the latter is prevented from rotating by keyway locking to the sleeve (38); the assembly's stabiiity is achieved by bolt (67) threaded to the free end of the traction shaft (3) and between both are a pressure washer and a flat lock washer (68) the outer edge of which is supported by a recessed step (69) provided on the inner surface of hub (1).

6. A vehicle front wheel release device according to the previous claims, whereby the mechanism obtained through the above claimed embodiment permits automatic engagement concurrently with engagement of the vehicle's front wheel drive system by employing same mechanism as those existing to that purpose, characterized in that said engagement remains coupled even upon deceleration of the vehicle, until disengagement of the four-wheel drive mechanism thereof.

7. Vehicle front wheel release device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.