WO2022239185A1 - Final drive - Google Patents

Abstract

This final drive comprises: a differential device including a casing that can rotate by being provided with a ring gear meshing with a shaft, and side gears accommodated in the casing and coupled to respective axles; a clutch member accommodated in the casing and locked to the casing by linking with one of the side gears; an actuator disposed outside of the casing; and a housing. The actuator is provided with: a rotatable action member which can move in the direction of the clutch member and is drivingly coupled to the clutch member; a motor that is gear-coupled to the action member and rotates the action member; a counter member brought into contact with the action member; and a cam structure that converts the rotation of the action member relative to the counter member into motion in the axial direction and causes the clutch member to delink from/link to one of the side gears. The housing surrounds the differential device, the action member, and the counter member, and prevents rotation of the counter member.

Description

final drive

The following disclosure relates particularly to a final drive that is compact in the width direction.

As is well known, for example, in a rear wheel drive (FR) type automobile, the torque generated by the engine and/or motor is transmitted from the transmission to the final drive via the propeller shaft. The final drive contains a differential gear set that differentially distributes the transmitted torque to the right and left drive wheels.

A final drive may also include a clutch and its actuator for purposes such as limiting the differential of the differential gear set or cutting torque transmission to the drive wheels.

Patent Document 1 discloses an example of a device in which the entire actuator is inside a housing, and Patent Documents 2 and 3 disclose examples of a device in which a motor is placed outside and an internal clutch is operated by a cam mechanism.

Japanese Patent Application Publication No. 2017-067257 International Patent Application Publication WO2017/060963A1 Japanese Patent Application Publication No. 61-130646

Relatively lightweight vehicles, such as three-wheeled scooters, golf carts, microcars or buggies, have no choice but to narrow the distance between the left and right drive wheels. If the width of the final drive intervening between them is large, it will reduce the room for the axle to swing. In other words, how to make the final drive compact in the width direction is an important technical issue, especially in light vehicles. What is disclosed below was created in view of such problems.

According to one aspect, the final drive for transmitting torque input to a shaft directed toward a first axis to a pair of axles directed toward a second axis includes a ring gear meshing with the shaft. a differential device comprising: a casing rotatable about a second axis; side gears housed in the casing and respectively coupled to the axles; and an actuator located outside the casing, the actuator being a flat plate oriented at least partially perpendicular to the second axis and rotatable about the second axis. an action member movable in the direction of the second axis, the action member drivingly coupled to the clutch member; a motor gear coupled to the action member for rotating about the second axis; A counter member partially oriented perpendicular to said second axis and abutting against said action member, and for converting rotation of said action member relative to said counter member into movement in the direction of said second axis. an actuator having a cam structure that disengages the clutch member from one of the side gears; and a housing that surrounds the differential device, the action member, and the counter member and prevents the counter member from rotating. Prepare.

FIG. 1 is a schematic diagram showing the basic configuration of a rear-wheel drive vehicle. FIG. 2 is a perspective view showing the inside of the final drive partly cut away according to the present embodiment. FIG. 3 is a longitudinal sectional view of the final drive. FIG. 4 is an exploded perspective view of the actuator. FIG. 5 is a perspective view of the differential, primarily showing the portion where the actuator and clutch member are coupled; FIG. 6 is a cross-sectional view of the action member and the counter member along the circumferential direction, explaining the operation of the actuator.

Several exemplary embodiments are described below with reference to the accompanying drawings. It should be especially noted that the drawings are not necessarily drawn to scale and therefore the dimensional relationships to each other are not limited to those shown.

The final drive according to this embodiment can be used to drive the rear wheels of light vehicles such as three-wheeled scooters, golf carts, microcars or buggies, but of course also for front wheel drive and four wheel drive (4WD) vehicles. alternatively, it can be applied to other drive types. 1 and 3, the top of the drawing is the front F with respect to the vehicle, and the right and left of the drawing are right R and left L, respectively. However, in FIG. 2, the lower right of the figure is the front F. Of course, front and back and right and left can be arbitrarily exchanged.

Referring to FIG. 1, vehicle 1 generally includes engine/motor 3 and transmission 5 . Part of the torque produced by the engine/motor 3 may be distributed to both front wheels via the transmission 5 and another part is extracted via the power transfer unit 7 to the propeller shaft 9 and via the final drive 11. are distributed to both rear wheels 17R and 17L.

The rear wheels 17R, 17L are normally able to float with respect to the vehicle body in order to absorb the unevenness of the road surface. In order to allow the rear wheels 17R and 17L to float, for example, constant velocity joints 25 are interposed in the axles 19R and 19L, respectively, so that the axles 19R and 19L can oscillate about these fulcrums. If the final drive 11 is compact in the width direction, the distance between the fulcrums can be made longer, which is advantageous in securing the room for swinging of the axles 19R and 19L. Such an advantage is particularly advantageous for lightweight vehicles, since a sufficient span between the rear wheels 17R and 17L cannot be obtained in such vehicles.

Referring primarily to Figure 2, the final drive 11 comprises a housing 13 which is generally laterally oriented and drum-shaped. A jacket portion extends forward F from the housing 13 in the direction of the axis C1, and a shaft 21 pulled out from the jacket portion is rotatable around the axis C1. Shaft 21 receives input torque and differential 33 in housing 13 transfers torque about axis C2 which is non-parallel to axis C1 to axles 19R and 19L. Differential 33 distributes torque differentially when unlocked.

At its outer end, the shaft 21 can be fixedly provided with, for example, a companion flange, so that it can be drivingly connected with the propeller shaft 9 . Alternatively, splines or other coupling means may be provided in place of the companion flange.

A combination of the pinion gear 23 and the ring gear 31 is used to transmit torque from the shaft 21 to the differential device 33 . For torque transmission in different axial directions, these are usually, but not necessarily, spiral or hypoid gears. A pinion gear 23 may be integral with the inner end of the shaft 21 .

The differential device 33 has a casing 35 rotatable around the axis C2, and the ring gear 31 is coupled to the outer periphery of the casing 35. Coupling can be by fastening, welding, or other means. Through the pinion gear 23 and the ring gear 31, the differential device 33 receives torque around the axis C2 and rotates.

Referring to FIG. 3 in combination with FIG. 2, the casing 35 includes therein a differential gear set having side gears 37R and 37L for outputting torque to the axles 19R and 19L, respectively, and a gear between the side gears 37R and 37L. and a clutch member 43 for locking the differential.

The differential gear set may be a simple differential or a so-called limited slip differential (LSD). Also, in the examples shown in FIGS. 2 and 3, the differential gear set is of the bevel gear type, but other gear sets such as face gear type or planetary gear type can be used.

One of the side gears 37R, 37L, for example, the right side gear 37R, has dog teeth, and the clutch member 43 has corresponding dog teeth, which mesh with each other to lock the right side gear 37R to the casing 35, thereby locking the side gears 37R, 37L. lock the differential between Other coupling structures, such as a key and keyway combination, may be used in place of dog teeth.

4 in combination with FIGS. 2 and 3, the final drive 11 comprises a motor 39 and an actuator 41 to drive the clutch member 43. As shown in FIG. The motor 39 imparts rotary motion to the actuator 41 through the gear shaft 39G, and the actuator 41 converts the rotary motion into axial motion to drive the clutch member 43. As shown in FIG.

The actuator 41 is located within the housing 13 but outside the casing 35 and close to the clutch member 43 . The actuator 41 generally includes an action member 51 that is driven by the motor 39 to rotate around the axis C2, and a counter member 53 that abuts against the action member 53 and is prevented from rotating. A base member 59 may also be provided to position them with respect to the housing 13 .

The action member 51, the counter member 53, and the base member 59 are all obtained by punching a flat plate made of steel for machine structural use, for example, into an annular shape and cutting. One or both of the counter member 53 and the base member 59 comprise partially bent pawl structures for mutual engagement, and one or both of the action member 51 and the counter member 53 partially Although they are press-formed to have cam slopes 51C and 53C, they are generally relatively thin flat plates. Both are oriented substantially perpendicular to the axis C2, the action member 51 and the counter member 53 are in contact with each other, and the base member 59 is only slightly separated from them, so that the whole is very small in the direction of the axis C2. Dimensions.

The action member 51 is generally annular, as already mentioned, but a relatively limited portion of its outer periphery may extend slightly outward in the radial direction, for example, such a portion may be provided with a ring for engaging the gear shaft 39G. of gear teeth 51G. The action member 51 receives a driving force through the gear teeth 51G and rotates around the axis C2. Needless to say, both forward and reverse rotations are possible.

In the example shown in FIGS. 2 and 3, the motor 39 is fixed to the housing 13, its body protrudes outside the housing 13, and only the gear shaft 39G protrudes into the housing 13 and meshes with the gear teeth 51G. The arrangement of the motor 39 is not limited to this, and most of it may be inside the housing 13 . Alternatively, the motor 39 may be a hollow shaft motor that is coaxial with the axis C2 and surrounds the actuator 41 . In that case, the hollow shaft may be coupled to the outer circumference of the action member 51, or the hollow shaft and the action member 51 may be integrated.

The counter member 53 and the base member 59 are engaged with each other, thereby restricting movement in both the axial direction and the circumferential direction, or may be fixed. The base member 59 also engages or is secured to the housing 13 so that the entirety of them is prevented from rotating. Alternatively, as best shown in FIG. 2, a bracket 45 may extend from actuator 41 and engage housing 13 for detent.

Referring back to FIG. 4 in combination with FIGS. 2 and 3, as understood from the above description, the counter member 53 is prevented from rotating around the axis C2 and is restricted from moving in the direction of the axis C2. However, the action member 51 is rotatable around the axis C2 and also movable in the direction of the axis C2. A spring 55 can be utilized to appropriately urge the action member 51 toward the counter member 53 to keep it in constant contact therewith. The spring 55 can be elastically interposed between the action member 51 and the base member 59, for example. Alternatively, if possible, the spring 55 may be replaced by other suitable biasing means.

A transfer member 57 may be interposed therebetween in order to transmit the axial motion of the action member 51 to the clutch member 43 . The transfer member 57 may be engaged with the action member 51, such engagement permitting circumferential sliding, or ball bearings or the like may intervene to facilitate relative rotation. The connection between the clutch member 43 and the transfer member 57 can be made by, for example, a bolt 61, and a leg 57L extending from the transfer member 57 can be used for the bolt connection.

The clutch member 43 is generally a thick annular ring, one surface of which is connected to the action member 51 or transfer member 57, and the other surface of which is provided with dog teeth. Further, for example, on its outer periphery, it is provided with lugs 43L for coupling with the casing 35, and correspondingly, the casing 35 is provided with grooves that allow axial movement while engaging with the lugs 43L.

A spring 29 may be interposed between the clutch member 43 and the inner surface of the casing 35 in order to appropriately bias the clutch member 43 so that it is always connected to the side gear 37R. If possible, the spring 29 may be replaced by other suitable biasing means. In this example, the clutch member 43 is always connected to the side gear 37R, and is disconnected only when the actuator 41 is actuated. Alternatively, conversely, the clutch member 43 may always be disconnected from the side gear 37R and connected only when the actuator 41 is actuated. Since the actuator 41 can drive the clutch member 43 bi-directionally, either configuration can be easily realized depending on the direction in which the spring 29 biases.

5 in combination with FIGS. 2 through 4, one end of the casing 35 is provided with one or more through holes 35P through which the legs 57L of the transfer member 57 each reach the clutch member 43 through the through holes 35P and the bolts 61. and so on. The through hole 35P can be relatively small so that the strength and rigidity of the casing 35 are not compromised.

6 in combination with FIGS. 2 to 5, the combination of the action member 51 and the counter member 53 has a cam structure that converts the rotational motion of the action member 51 by the motor 39 into axial motion. One example is the cam slopes 51C and 53C already mentioned. The action member 51 and the counter member 53 may be provided with cam slopes 51C and 53C, respectively, or only one of them may be provided with the cam slopes and the other may be provided with a structure such as an opening for receiving the cam slopes. good. In any event, the action member 51 and the counter member 53 abut each other in the cam structure, preferably in surface contact with each other.

The cam slopes 51C and 53C are slopes integrally protruding from the action member 51 and the counter member 53, respectively, and are inclined in the circumferential direction around the axis C2. Needless to say, the direction in which the slopes protrude may be opposite to that in the drawing, and the inclination may also be in the opposite direction. When the action member 51 undergoes a circumferential rotational motion Rm, the cam slopes 51C and 53C guide the action member 51 to cause an axial motion M thereof.

In FIG. 6, the clutch member 43 remains connected to the side gear 37R at the solid line position, and the action member 51 disconnects the clutch member 43 when pushed up to the two-dot chain line position. At this time, the differential of the differential device 33 is allowed. As already described, the contact between them is maintained by the biasing force of the spring 55, so if the action member 51 rotates in the opposite direction, it returns from the position indicated by the two-dot chain line to the position indicated by the solid line. At this time, the differential of the differential device 33 is locked again.

As understood from the above description, the rotation angle of the motor 39 accurately reflects the axial movement of the clutch member 43. Using this, it may be determined whether the clutch is engaged or disengaged from the rotation angle of the motor 39 .

Referring back to Figures 2 and 3, at least the differential 33 and the actuator 41 are housed in the combination of the housing 13 and the cover 15 coupled thereto. The housing 13 and the cover 15 are separated and joined in the width direction (along the axis C2) rather than in the longitudinal direction (along the axis C1), in a so-called side cover type form. The housing 13 includes a main body portion 13B surrounding the differential device 33 and other elements, and a wall portion 13W integral therewith and covering the sides thereof. The wall portion 13W cannot be separated from the body portion 13B, but the cover 15 can be separated and covers the side surface opposite to the wall portion 13W. Wall 13W has an opening to receive the left axle (which, of course, could be the right axle), and cover 15 has an opening to receive the right axle (or left axle), but with both axles inserted. is blocked from the outside.

The jacket portion protrudes forward F from the body portion 13B and is open at its front end. A bore in the jacket portion receives and supports the shaft 21 . The bore may be at least large enough to allow the pinion gear 23 to pass through, or may be sized to support a bearing unit that rotatably supports the shaft 21 .

When the cover 15 is separated from the housing 13, an opening appears to allow access to the interior of the main body 13B, through which the differential 33 and actuator 41 can be installed. The opening is large enough to allow the ring gear 31 to pass through, and the internal chamber is designed so that the ring gear 31 inserted through the opening can move along the axis C2 to the vicinity of the wall portion 13W. dimensioned.

The ring gear 31 is very close to the wall portion 13W, and the pinion gear 23 is slightly closer to the center than this and meshes with each other. When viewed from the wall portion 13W toward the cover 15 or along the axis C2, the wall portion 13W, the ring gear 31, the shaft 21 including the pinion gear 23, the clutch member 43, and the actuator 41 are arranged in this order. there is Further, when viewed along the axis C2, the casing 35 and the pinion gear 23 can be arranged so as to overlap each other. Such an arrangement is advantageous for miniaturizing the final drive 11 in the width direction.

The left end (or right end) 35L of the casing 35 is supported by the wall portion 13W, and the right end (or left end) 35R is supported by the cover 15. A ball bearing may be interposed in each to allow rotation, and of course, instead of the ball bearings, roller bearings or other bearing elements may also be used.

The openings may each have a fixed seal to prevent leakage of fluid, such as lubricating oil, from around each axle. The seals may be arranged radially inwardly of the bearings and may overlap each other in the direction of axis C2. Such an arrangement eliminates the need for a structure protruding in the direction of the axis C2 around the opening, ie, helps to reduce the size in the width direction.

As already mentioned, since the ring gear 31 is closer to the wall portion 13W than the shaft 21 including the pinion gear 23, there is a space left in the housing 13 closer to the cover 15, in which the actuator 41 is installed. can be placed. Since the actuator 41 is generally a combination of flat plates, it is very thin, and therefore the cover 15 does not need to protrude laterally in order to secure a space for housing the actuator 41 . The entire housing 13 including the cover 15 can be made compact in the width direction. Since the ring gear has the largest diameter of all the internal parts, it is expected that, according to common sense, it would be disadvantageous to make the housing smaller if the housing 13 were dimensioned so that it could be arranged in the innermost position. It's just around the corner. In this embodiment, such an unconventional arrangement is intentionally adopted to realize a compact configuration in the width direction. As already mentioned, the compact configuration in the width direction brings about various benefits, such as ensuring sufficient room for swinging of the axles 19R and 19L.

Also, with such an arrangement, the motor 39 can be retrofitted together with the cover 15 and assembly of the elements within the housing 13 is very easy.

On the other hand, in the arrangement according to this embodiment, the problem is how to mesh the pinion gear 23 and the ring gear 31 . This is because unlike the prior art, the pinion gear 23 cannot be arranged first and the ring gear 31 can not be meshed afterwards. In this embodiment, the ring gear 31 is arranged first, and the shaft 21 can be inserted through the opening of the jacket portion to be incorporated later, so that such a problem can be solved. For gear mesh adjustment, shaft 21 may be provided with a mesh adjustment mechanism.

Although several embodiments have been described, it is possible to modify or modify the embodiments based on the above disclosure.

Claims (4)

A final drive for transmitting torque input to a shaft oriented to a first axis to a pair of axles oriented to a second axis,
a differential device comprising: a casing having a ring gear meshing with the shaft and rotatable around the second shaft; and side gears housed in the casing and coupled to the axle, respectively;
a clutch member that is housed in the casing and connected to one of the side gears and locked to the casing;
An actuator arranged outside the casing,
an action member at least partially oriented perpendicular to said second axis, said action member being rotatable about said second axis and movable in the direction of said second axis, said clutch member an action member drivingly coupled to the
a motor coupled with a gear to the action member to rotate around the second axis;
a counter member, which is a flat plate oriented at least partially perpendicular to the second axis, abutting the action member;
an actuator comprising a cam structure that converts rotation of the action member relative to the counter member into motion in the direction of the second axis to disconnect the clutch member from one of the side gears;
a housing that surrounds the differential device, the action member, and the counter member and prevents the counter member from rotating;
final drive with The final drive of claim 1, wherein said cam structure is one or more cam ramps projecting integrally from one or both of said action member and said counter member in the direction of said second axis. The final drive of claim 2, wherein said cam ramp is circumferentially inclined about said second axis. The housing includes a wall through which one of the axles penetrates and a separable cover through which the other of the axles penetrates. From the wall toward the cover, the wall, the ring gear, the 2. The final drive of claim 1, wherein the order is the clutch member, the action member, and the cover.

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