GB2229502A - Self-locking differential unit - Google Patents
Self-locking differential unit Download PDFInfo
- Publication number
- GB2229502A GB2229502A GB9004577A GB9004577A GB2229502A GB 2229502 A GB2229502 A GB 2229502A GB 9004577 A GB9004577 A GB 9004577A GB 9004577 A GB9004577 A GB 9004577A GB 2229502 A GB2229502 A GB 2229502A
- Authority
- GB
- United Kingdom
- Prior art keywords
- differential
- gears
- output
- engaging
- axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 125000006850 spacer group Chemical group 0.000 claims description 6
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 238000005755 formation reaction Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims 1
- 230000009699 differential effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 230000005764 inhibitory process Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H48/00—Differential gearings
- F16H48/20—Arrangements for suppressing or influencing the differential action, e.g. locking devices
- F16H48/28—Arrangements for suppressing or influencing the differential action, e.g. locking devices using self-locking gears or self-braking gears
- F16H48/285—Arrangements for suppressing or influencing the differential action, e.g. locking devices using self-locking gears or self-braking gears with self-braking intermeshing gears having parallel axes and having worms or helical teeth
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H48/00—Differential gearings
- F16H48/06—Differential gearings with gears having orbital motion
- F16H48/10—Differential gearings with gears having orbital motion with orbital spur gears
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H48/00—Differential gearings
- F16H48/06—Differential gearings with gears having orbital motion
- F16H48/10—Differential gearings with gears having orbital motion with orbital spur gears
- F16H48/11—Differential gearings with gears having orbital motion with orbital spur gears having intermeshing planet gears
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H48/00—Differential gearings
- F16H48/06—Differential gearings with gears having orbital motion
- F16H48/10—Differential gearings with gears having orbital motion with orbital spur gears
- F16H2048/106—Differential gearings with gears having orbital motion with orbital spur gears characterised by two sun gears
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Retarders (AREA)
Description
1 GMD/8817OGB1 DIFFERENTIAL UNIT This invention relates to a differential
unit comprising a differential carrier, drivable for rotation about an axis, and output gears supported within the carrier and rotatable relative thereto about said axis, the diameters of the output gears being different from one another. Such a differential unit distributes torque unequally between the two output gears by virtue of their different diameters, and is therefore useful, for example, as a centre (inter-axle) differential in a four wheel drive vehicle, where such unequal torque distribution may be desirable.
An example of such a differential unit is disclosed in International Published Patent Application W087/00900. In this differential unit there are provided differential gears within the differential carrier, half of which differential gears engage one of the output gears and half of which engage the other output gear, being axis-parallel thereto. A connection between the respective differential gears is provided by two worm gears, between which there exists a parallel force-fitting connection, disposed in a space axially between the output gears, the axes of the worm gears being spaced from the axes of the output gears and of the differential gears. The teeth of the worm gears require the differential gear teeth to be designed accordingly, and since they extend into the region of engagement with the output gears these also have to be designed with the same type of teeth. The friction in the engagement between the differential gears and the worm gear causes the differential to have a slip-limiting or partial locking effect, to prevent 2 complete loss of traction at one of the driven axles, as is desirable in a four wheel drive vehicle.
The above described differential has a number of disadvantages. Because of the shape of their teeth, the gears used are relatively expensive to produce. Disposing the worm gear between the output gears increases the length of the differential unit to undesirable proportions. The design permits the use only of four differential gears with two worm gears, and thus the torque capacity is limited with the result that the teeth and thus the diameter of the differential gears have to be large, so that the diameter of the unit also is disadvantageously large.
It is broadly the object of the present invention to provide a differential unit in which the above disadvantages are overcome or reduced, i.e. it desirably should be of small dimensions, and be produceable at reasonable cost.
According to the present invention, we provide a differential unit comprising: a differential carrier drivable for rotation about an axis; first and second output gears supported within the carrier and rotatable relative thereto about said axis, the output gears being of different diameters from one another; and a plurality of differential gears supported in recesses in the differential carrier for rotation about axes parallel to said axis, and establishing a driving connection between said output gears for differential rotation thereof inhibited by friction between the 1 3 differential gears and their recesses in the differential carrier.
By providing the differential unit with differential gears disposed parallel to the axis of the carrier and output gears, it is possible to arrange a large number of the differential gears circumferentially around the unit, so that the overall diameter of the unit is kept to a minimum. Further, the output gears can be disposed close together, so that the length of the unit is kept to a minimum. Supporting the differential gears in the recesses in the carrier not only has the effect that friction provides the required inhibition of the differential action thereof, but reduces the space required because there is no need for any bearings supporting the differential gears.
If only a small inhibition or restriction of the differential action of the unit is required, the differential gears may have straight teeth, i.e. be simple parallel spur gears. If, however, a greater restriction of the differential action is required, helical gears may be utilised.
As far as the disposition of the output gears and differential gears is concerned, there is a choice of different configurations.
In a first embodiment, an even number of differential gears may be disposed in pairs arranged circumferentially about the unit, each pair comprising axially offset differential gears engaging each other and respectively engaging the output gears.
4 This design permits the smallest possible distance between the output gears, whose end faces may even rest against each other. A similar design, but not incorporating unequal torque distribution, is known from US 3,706,239.
In a second embodiment, based on the same principles, an even number of the differential gears may be disposed circumferentially about the axis, with alternate ones of the differential gears engaging one of the output gears and the other alternate ones engaging the other output gear, each differential gear engaging the two adjacent differential gears. In other words, the differential gears have "full circle" engagement with one another. In this embodiment, the self-inhibiting effect which resists differential action between the output gears is reduced, because each differential gear is subject to the opposing tooth forces of the adjacent differential gears. A differential unit which such full circle engagement between the differential gears is known from GB-1 099 717, but not with an unequal torque distribution.
Both embodiments of differential unit, especially the first above mentioned, have advantages in that the torque distribution can be relatively freely selected in accordance with the selected sizes of the output gears.
The differential carrier is preferably in two parts, divided in a plane transverse to said axis, generally between the output gears.
In a modification, the differential gears may be of 30 stepped diameter.
1 - A spacer member may be provided in the differential carrier between the output gears, having outwardly extending formations which form part of or complements the recesses in the carrier within which the differential gears are supported.
The invention will now be described by way of example with reference to the accompanying drawings, of which:- Figure 1 shows a first embodiment of differential unit according to the invention, Figure 1A being a transverse section on the stepped section line A-B of Figure 1B, and Figure 1B being a longitudinal section along the line C-D of Figure 1A; Figure 2 shows a further e;.-,bodiment of differential is unit according to the invention, Figures 2A and 2B being sections as Figures 1A and 1B.
Referring firstly to Figures 1A and 1B of the drawing, the differential there illustrated comprises a differential carrier 7 comprising two housing halves 8, 9 held together by bolts 10. Within the carrier 7 are disposed first and second output gears 1, 2, which are supported within the carrier for rotation about a common axis indicated at 12. The output gears have splined bores for torque transmitting engagement with respective output shafts which would extend in opposite directions along the axis 12, out of the differential carrier 7. It will be appreciated that as used in a motor vehicle, the carrier 7 would itself be supported for rotation about the axis 12, and would be arranged to be driven by e.g. a drive element engaging the flanged part of the housing half 8 through which the bolts 10 extend.
6 The housing halves 8, 9 define recesses in which are disposed differential gears. An even number (in this case eight) of differential gears are disposed in pairs, spaced circumferentially about the axis 12. There are four differential gears 3 disposed in respective recesses 5 in the housing half 8, engaging the output gear 1. There are four differential gears 4 disposed in recesses 6 in the housing half 9, engaging the output gear 2. The gears 3, 4, in each pair are axially offset from one another and mesh with one another as seen in the drawings. Because of the different diameters of the output gears, the differential gears 4 are disposed on a pitch circle of larger diameter than the differential gears 3.
Between the output gears 1, 2 there is disposed a spacer member 11, which has radially outwardly extending formations which provide part of the recesses wherein the differential gears 3, 4 are constrained. The differential gears overlap axially in the region of the spacer member 11.
Referring now to Figures 2A and 2B of the drawings these show a differential unit which differs from that of Figures 1A and IB in respect of the arrangement of the differential gears. The construction of the differential carrier is generally as that of Figure 1, and will not be described again in detail. The same reference numerals are used for parts corresponding to those appearing in Figure 1. As in Figure 1, the output gears 1, 2 are of different diameters.
The differential unit of Figure 2 comprises an even number of differential gears 3, 4 meshing with the output gears 1, 2 respectively. The differential gears 4 are of 7 larger diameter than the differential gears 3, and each differential gear 4 meshes with the two circumferentially adjacent differential gears 3. Similarly each differential gear 3 meshes with the two circumferentially adjacent differential gears 4. The spacer member 11 is considerably smaller in this embodiment than in the embodiment of Figure 1.
In each of the above described embodiments of differential unit, differential rotation between the output gears is inhibited by friction between the differential gears and the recesses in the differential carrier wherein they are disposed. The output and differential gears may be simple spur gears with axis-parallel teeth, or may be helically toothed if a greater inhibiting effect is required.
is 8
Claims (8)
1. A differential unit comprising: a differential carrier drivable for rotation about an axis; first and second output gears supported within the carrier and rotatable relative thereto about said axis, the output gears being of different diameters from one another; and a plurality of differential gears supported in recesses in the differential carrier for rotation about axes parallel to said axis, and establishing a driving connection between said output gears for differential rotation thereof inhibited by friction between the differential gears and their recesses in the differential carrier.
2. A differential unit according to Claim 1 comprising an even number of differential gears disposed in pairs which pairs are spaced circumferentially about said axis, each pair comprising axially offset differential gears engaging each other and respectively engaging the output gears.
3. A differential unit according to Claim 1 comprising an even number of differential gears disposed circumferentially about said axis, alternate ones of said differential gears engaging one of the output gears and the other alternate ones of the differential gears engaging the other output gear, each differential gear engaging the two adjacent differential gears.
4. A differential unit according to Claim 3 wherein the differential gears engaging with one of the output gears are of different diameter from the differential gears engaging the other output gear.
9
5. A differential unit according to Claim 1 wherein the differential gears engaging one of the output gears are disposed on a pitch circle of different diameter from the differential gears engaging the other output gear.
6. A differential unit according to Claim 1 wherein the differential carrier is divided in a plane transverse to said axis and between the output gears.
7. A differential unit according to Claim 6 wherein a spacer member is provided between the output gears, said spacer member having outwardly extending formations which provide part of the recesses wherein the differential gears are supported.
8. A differential unit substantially as hereinbefore described with reference to Figure 1 or Figure 2 of the accompanying drawings.
Published 1990 a., The Paten 0t2ce-Stae House 66-1 High Holbozr., Londor. WC1R 4TP. Fi--ther cop;es may be obtained frorn The Patent 0J11ce Sales Branch. S Mary Cray. Orpington. Kent BR5 3RD. Printed by Mwtiplex techniques ltd. St Mary Cray. Kent, Con. 1!87
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3906650A DE3906650A1 (en) | 1989-03-02 | 1989-03-02 | DIFFERENTIAL GEARBOX |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9004577D0 GB9004577D0 (en) | 1990-04-25 |
| GB2229502A true GB2229502A (en) | 1990-09-26 |
| GB2229502B GB2229502B (en) | 1993-01-20 |
Family
ID=6375347
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9004577A Expired - Fee Related GB2229502B (en) | 1989-03-02 | 1990-03-01 | Differential unit |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH02266142A (en) |
| DE (1) | DE3906650A1 (en) |
| FR (1) | FR2643962B1 (en) |
| GB (1) | GB2229502B (en) |
| IT (1) | IT1241422B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992012361A1 (en) * | 1991-01-09 | 1992-07-23 | Group Lotus Plc | Differential unit |
| US5147252A (en) * | 1988-06-15 | 1992-09-15 | Group Lotus P/C | Differential unit |
| US5194054A (en) * | 1990-04-25 | 1993-03-16 | Viscodrive Gmbh | Differential drive |
| US5484348A (en) * | 1991-08-14 | 1996-01-16 | Lotus Cars Ltd. | Differential unit |
| US5518464A (en) * | 1992-12-18 | 1996-05-21 | Tochigi Fugi Sangyo Kabushiki Kaisha | Torque divider |
| US5647815A (en) * | 1995-09-05 | 1997-07-15 | Zexel Torsen Inc. | Differential with bias control |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4036014C2 (en) * | 1990-11-13 | 2001-07-05 | Truetzschler Gmbh & Co Kg | Device for producing a nonwoven fabric, e.g. made of chemical fibers, cotton, rayon and the like the like |
| DE4217784C2 (en) * | 1991-06-12 | 1994-02-17 | Viscodrive Gmbh | Differential gear |
| DE4223374C2 (en) * | 1992-07-16 | 1994-09-15 | Viscodrive Gmbh | Differential gear |
| US9347542B2 (en) | 2008-09-30 | 2016-05-24 | American Axle & Manufacturing, Inc. | Parallel-axis helical differential assembly |
| US20170175868A1 (en) * | 2015-12-16 | 2017-06-22 | Atieva, Inc. | Parallel Axis Epicyclic Gear Differential |
| FR3078295B1 (en) * | 2018-02-28 | 2020-01-24 | Psa Automobiles Sa | TORSEN TYPE DIFFERENTIAL DELIVERING DIFFERENT TORQUES ON TWO OUTPUT SHAFTS |
| DE102019100374B4 (en) * | 2018-11-28 | 2021-07-22 | Schaeffler Technologies AG & Co. KG | Spur gear differential gear with coupling planets that differ by profile shifting |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB622351A (en) * | 1947-03-14 | 1949-04-29 | Ralph Russell Randall | Non-equalizing torque differential transmission |
| GB1099717A (en) * | 1964-04-30 | 1968-01-17 | Illinois Tool Works | Spin limiting differentials |
| US3706239A (en) * | 1971-02-09 | 1972-12-19 | Boise Cascade Corp | Pinion differential mechanism having internal bias torque |
| WO1987000900A1 (en) * | 1985-07-31 | 1987-02-12 | Mechadyne Limited | Torque-apportioning differential mechanism for motor vehicles |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT2614B (en) * | 1899-05-20 | 1900-11-10 | Ludwig Czischek | |
| US3738192A (en) * | 1971-06-29 | 1973-06-12 | Illinois Tool Works | Limited slip differential mechanisms |
| US3792628A (en) * | 1972-07-03 | 1974-02-19 | Mack Trucks | Torque proportioning and spin limiting differential |
| GB1451358A (en) * | 1973-01-26 | 1976-09-29 | Aspro Inc | Limited slip differential with paired roller pinions |
| DE68910885T2 (en) * | 1988-06-15 | 1994-03-17 | Group Lotus Plc Norwich | Differential unit. |
-
1989
- 1989-03-02 DE DE3906650A patent/DE3906650A1/en active Granted
-
1990
- 1990-02-22 IT IT19454A patent/IT1241422B/en active IP Right Grant
- 1990-03-01 GB GB9004577A patent/GB2229502B/en not_active Expired - Fee Related
- 1990-03-02 FR FR9002682A patent/FR2643962B1/en not_active Expired - Fee Related
- 1990-03-02 JP JP2049693A patent/JPH02266142A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB622351A (en) * | 1947-03-14 | 1949-04-29 | Ralph Russell Randall | Non-equalizing torque differential transmission |
| GB1099717A (en) * | 1964-04-30 | 1968-01-17 | Illinois Tool Works | Spin limiting differentials |
| US3706239A (en) * | 1971-02-09 | 1972-12-19 | Boise Cascade Corp | Pinion differential mechanism having internal bias torque |
| WO1987000900A1 (en) * | 1985-07-31 | 1987-02-12 | Mechadyne Limited | Torque-apportioning differential mechanism for motor vehicles |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5147252A (en) * | 1988-06-15 | 1992-09-15 | Group Lotus P/C | Differential unit |
| US5194054A (en) * | 1990-04-25 | 1993-03-16 | Viscodrive Gmbh | Differential drive |
| US5342256A (en) * | 1990-04-25 | 1994-08-30 | Viscodrive Gmbh | Differential gear system |
| WO1992012361A1 (en) * | 1991-01-09 | 1992-07-23 | Group Lotus Plc | Differential unit |
| US5484348A (en) * | 1991-08-14 | 1996-01-16 | Lotus Cars Ltd. | Differential unit |
| US5518464A (en) * | 1992-12-18 | 1996-05-21 | Tochigi Fugi Sangyo Kabushiki Kaisha | Torque divider |
| US5647815A (en) * | 1995-09-05 | 1997-07-15 | Zexel Torsen Inc. | Differential with bias control |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3906650A1 (en) | 1990-09-13 |
| FR2643962A1 (en) | 1990-09-07 |
| GB9004577D0 (en) | 1990-04-25 |
| GB2229502B (en) | 1993-01-20 |
| IT9019454A0 (en) | 1990-02-22 |
| FR2643962B1 (en) | 1993-03-26 |
| JPH02266142A (en) | 1990-10-30 |
| IT9019454A1 (en) | 1991-08-22 |
| IT1241422B (en) | 1994-01-14 |
| DE3906650C2 (en) | 1992-10-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19960301 |