GB2049073A - Continuously-variable ratio transmission - Google Patents
Continuously-variable ratio transmission Download PDFInfo
- Publication number
- GB2049073A GB2049073A GB7910437A GB7910437A GB2049073A GB 2049073 A GB2049073 A GB 2049073A GB 7910437 A GB7910437 A GB 7910437A GB 7910437 A GB7910437 A GB 7910437A GB 2049073 A GB2049073 A GB 2049073A
- Authority
- GB
- United Kingdom
- Prior art keywords
- layshaft
- drive
- gear
- coupling
- 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
- 230000005540 biological transmission Effects 0.000 title claims abstract description 24
- 230000008878 coupling Effects 0.000 claims abstract description 19
- 238000010168 coupling process Methods 0.000 claims abstract description 19
- 238000005859 coupling reaction Methods 0.000 claims abstract description 19
- 230000007246 mechanism Effects 0.000 claims abstract description 13
- 238000002485 combustion reaction Methods 0.000 claims abstract description 5
- 239000012530 fluid Substances 0.000 claims abstract description 5
- 230000007935 neutral effect Effects 0.000 description 1
Classifications
-
- 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
- F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
- F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
- F16H37/021—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings toothed gearing combined with continuous variable friction gearing
-
- 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
- F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
- F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
- F16H9/04—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes
- F16H9/12—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transmission Devices (AREA)
- Structure Of Transmissions (AREA)
- Transmissions By Endless Flexible Members (AREA)
Abstract
A continuously variable ratio transmission for use in a vehicle powered by an internal combustion engine incorporates a fluid coupling and a variator input section 14 coaxial with the engine. The variator output 16 and a differential unit 29 are both arranged on a second axis but are not coupled directly together. The output sheave carries two gears which mesh with two further gears rotatable independently on a layshaft 22. A clutch or synchromesh mechanism connects either of the layshaft gears selectively for rotation with the layshaft. A final drive gear 27 on the layshaft drives the differential unit which in turn drives the front wheels of a front wheel drive car. <IMAGE>
Description
SPECIFICATION
Variable ratio transmission mechanisms
The invention relates to variable ratio transmission mechanisms. The invention is particularly concerned with continuously variable transmission mechanisms for use as the main drive transmission in a vehicle powered by an internal combustion engine.
There is a continuous pressure in the automotive industry and particularly in connection with small front wheel drive cars to provide an increased space within the vehicle without increasing the overall dimensions. This in turn results in a pressure towards compact engine and transmission units and to engine and transmission units which as a whole have a shape which can conveniently be fitted into a space available such as the space between the two front wheels of the vehicle.
The present invention is concerned with the provision of a continuously variable ratio transmission which assists in the provision of a compact and suitably shaped engine-transmission unit. The transmission is of the kind which incorporates a variator. A variator is constituted by a pair of sheaves, each in the form of an adjustable
V-pulley, and a flexible friction drive belt or chain interconnecting the two sheaves. Adjustment of the effective diameters of the sheaves by axial adjustment of the relative positions of the two pulley halves of the sheaves, varies the transmission ratio.
According to the present invention there is provided a continuously variable transmission mechanism for use in a vehicle powered by an internal combustion engine for incorporating a variator input sheave on a first axis co-axial with the engine, an output sheave on a second axis parallel to the first axis, a differential unit co-axial with the output sheave, a layshaft parallel to the second axis and a reduction drive from the output sheave via the layshaft to the differential unit.
Preferably there is a coupling member co-axial with the engine for coupling the drive from the engine to the variator.
Preferably there is a direct drive path from a gear rotatable with the output sheave to a gear on the layshaft for the reduction gear drive, an alternative drive from a gear rotatable with the output sheave~through a reversing idler gear to a gear on the layshaft to establish a reverse drive and means for selectively engaging either the reduction or the reverse drive.
Preferably the coupling is a fluid coupling.
However, as an alternative, a different form of coupling such as a friction clutch may be used and the friction clutch may be controlled centrifugally or otherwise.
An embodiment of the invention will now be described by way of example only with reference to the accompanying drawing which is a diagrammatic cross section through one form of transmission mechanism.
The continuously variable ratio transmission mechanism shown in the drawing is intended for use as the main drive transmission of a car powered by an internal combustion engine. The engine, not shown, is arranged with its crank shaft axis co-axial with an input shaft 11 to the transmission with the engine immediately to the left (as shown) of the transmission. The input shaft 11 is selectably connectable by means of a friction clutch 12 and a further shaft 13 to the input sheave 14 of a variator 15. As an alternative to the friction clutch 12, a different form of coupling such as a fluid coupling may be used.
The variator 1 5 also incorporates an output sheave 1 6 which is arranged on a second axis parallel to but displaced from the first axis of the engine and input sheave. A frictional drive band 1 7 interconnects the input and output sheaves with a drive ratio depending on the settings of the two sheaves.
The output sheave 1 6 is carried on a sleeve 1 8 which carries a forward drive gear 1 9 and a reverse drive gear 21. A layshaft 22 is offset from the second axis of the output sheave and is arranged generaily between the first and second axes, but possibly offset slightly from their common plane, with a view to limiting the exterior dimensions of the transmission mechanism. The forward gear 1 9 meshes with a first layshaft gear 23 which is rotatable freely on the layshaft 22.
The reversing gear 21 meshes with a reversing idler gear 24 which in turn meshes with a second layshaft gear 25 which is also rotatable freely on the layshaft.
A further coupling 26 which may be a dog clutch arrangement with synchromesh or may be constituted by two cone clutches enables either the first layshaft gear 23 or the second layshaft gear 25 to be connected selectively to the layshaft 22. In an intermediate position, both gears 23 and 25 remain free to rotate on the layshaft.
The layshaft 22 also carries a final drive gear 27 which meshes with a ring gear 28 of a differential unit 29. The differential gear unit 29 is arranged to drive to output shafts 31 and 32 through universal joints 33 and 34 and the output shafts may drive the front wheels of a front wheel drive road vehicle.
In operation, to establish forward drive, coupling 26 is engaged with gear 23 to provide a forward drive path through the layshaftfrom the output sheave to the differential unit. The clutch
12 is then engaged to establish forward drive. The ratio of this drive is variable in the usual way by adjustment of the variator 1 5.
In order to engage reverse drive, coupling 26 is engaged with gear 27 instead of with gear 23 to establish a reverse drive path at a lower ratio than the forward reduction ratio between the output sheave 1 6 and the differential unit 29.
As an alternative to the coupling 26 for selective engagement of gears 23 and 25 to the layshaft 22, these gears may be fixed to the layshaft and a selective coupling provided between the sleeve 1 8 and each of gears 1 9 and 21.
If the friction clutch 12 is replaced by a fluid coupling, the intermediate position of coupling 26 in which both gears 23 and 27 remain free to rotate on the layshaft 22 is particularly useful because this provides the transmission with a neutral condition which is free of creep and allows the vehicle engine to run at high speed while the vehicle is stationary.
Claims (5)
1. A continuously variable ration transmission mechanism for use in a vehicle powered by an internal combustion engine and incorporating a variator input sheave on a first axis coaxial with the egine, an output sheave on a second axis
parallel to the first axis, a differential unit co-axial
with the output sheave, a layshaft parallel to the
second axis and a reduction drive from the output
sheave via the layshaftto the differential unit.
2. A transmission mechanism as claimed in
Claim 1 including a coupling member co-axial with the engine for coupling the drive from the engine to the variator.
3. A transmission mechanism as claimed in
Claim 1 or Claim 2 in which there is a direct drive path from a gear rotatable with the output sheave to a gear on the layshaft for the reduction gear drive, an alternative drive from a gear rotatable with the output sheave through a reversing idler gear to a gear on the layshaft to establish a reverse drive and means for selectively engaging either the reduction drive or the reverse drive.
4. A transmission mechanism as claimed in any preceding claim wherein the coupling is a fluid coupling.
5. A continuously variable transmission mechanism substantially as described with reference to and as illustrated by the accompanying drawing.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB7910437A GB2049073B (en) | 1979-03-24 | 1979-03-24 | Continuously-variable ratio transmission |
DE19803000270 DE3000270A1 (en) | 1979-03-24 | 1980-01-05 | CONTINUOUSLY ADJUSTABLE MOTOR VEHICLE TRANSMISSION |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB7910437A GB2049073B (en) | 1979-03-24 | 1979-03-24 | Continuously-variable ratio transmission |
Publications (2)
Publication Number | Publication Date |
---|---|
GB2049073A true GB2049073A (en) | 1980-12-17 |
GB2049073B GB2049073B (en) | 1982-12-08 |
Family
ID=10504119
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB7910437A Expired GB2049073B (en) | 1979-03-24 | 1979-03-24 | Continuously-variable ratio transmission |
Country Status (2)
Country | Link |
---|---|
DE (1) | DE3000270A1 (en) |
GB (1) | GB2049073B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3217548A1 (en) * | 1981-05-14 | 1983-02-17 | Mitsubishi Electric Corp | Power transmission device |
CN106195191A (en) * | 2015-05-29 | 2016-12-07 | 通用汽车环球科技运作有限责任公司 | There is infinitely variable speeds and finally drive the double-clutch speed changer of assembly |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3375381D1 (en) * | 1982-04-19 | 1988-02-25 | Nissan Motor | Method and apparatus for controlling reduction ratio of continuously variable transmission |
US4873879A (en) * | 1987-09-08 | 1989-10-17 | Borg-Warner Automotive, Inc. | Variable speed transmission |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2420062A1 (en) * | 1978-03-16 | 1979-10-12 | Renault | VARIATOR TRANSMISSION |
IT1159899B (en) * | 1978-07-13 | 1987-03-04 | Fiat Spa | TRANSMISSION UNIT FOR MOTOR VEHICLES |
-
1979
- 1979-03-24 GB GB7910437A patent/GB2049073B/en not_active Expired
-
1980
- 1980-01-05 DE DE19803000270 patent/DE3000270A1/en active Granted
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3217548A1 (en) * | 1981-05-14 | 1983-02-17 | Mitsubishi Electric Corp | Power transmission device |
CN106195191A (en) * | 2015-05-29 | 2016-12-07 | 通用汽车环球科技运作有限责任公司 | There is infinitely variable speeds and finally drive the double-clutch speed changer of assembly |
CN106195191B (en) * | 2015-05-29 | 2018-11-16 | 通用汽车环球科技运作有限责任公司 | Double-clutch speed changer with the final driving assembly of variable speed |
Also Published As
Publication number | Publication date |
---|---|
DE3000270C2 (en) | 1987-07-30 |
GB2049073B (en) | 1982-12-08 |
DE3000270A1 (en) | 1980-10-02 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |