CA1048813A

CA1048813A - Torque converter transmissions

Info

Publication number: CA1048813A
Application number: CA75240750A
Authority: CA
Inventors: Randle L. Abbott
Original assignee: GKN Transmissions Ltd
Current assignee: GKN Automotive Ltd
Priority date: 1974-11-26
Filing date: 1975-11-26
Publication date: 1979-02-20
Also published as: DE2552880A1; IT1051285B; GB1476950A

Abstract

ABSTRACT OF THE DISCLOSURE
An automatic transmission in the form of the combination of a geared torque converter and a duplex epicyclic gearset com-prising first and second co-axial sun gears, an annulus gear, a planet carrier carrying a first set of planet gear meshing with the first sun gear and the annulus gear and a second set of plan-et gears meshing with the second sun gear and with the planet gears of the first set. The arrangement is such that the duplex gear set provides high and low and forward and reverse ranges and a direct drive can be obtained by engaging a lock-up clutch.

Description

16~4881~

This invention relates to the combination of a hydrokinetic torque ccnverter with epicyclic gearing. Such a combination finds application as an automotive transmission between a prime mover and a final drive.
More specifically, the invention is concerned with the com-bination of a geared torque convertex with a duplex epicyclic gear set. When we refer to a geared torque converter we mean a hydro-kinetic torque converter including at least three elements viz an impeller, a turbine and a reaction member, the torque converter be-ing associated with one or more simple epicyclic gearsets (i.e. agearset including an annulus gear, a sun gear and at least two plan-et gears meshing with the annulus and sun gears) such that at least two elements of the torque converter are connected together through the gearset or gearsets so as to change the rotational speed of one of the connected elements of the converter, as compared with the speed of said one element if not so connected, in order to change ~ -the fluid flow characteristics and hence the performance of the con-verter. The geared torque converter will have an input to the im-peller, either directly or through a gearset, and an output from the turbine or turbines again directly or through a gearset.
It is an object of the invention to provide an improved com-bination of geared torque converter and epicyclic gearing.
According to the invention we provide the combination of:
(1) a geared torque converter; (2) a duplex epicyclic gearset co- -axial with the gearset or gearsets of the geared torque converter -and comprising first and second co-axial sun gears, an annulus gear, a planet carrier carrying a first set of planet gears meshing with the first sun gear and the annulus gear and a second set of planet gears meshing with the second sun gear and with the planet gears of the first set; (3) a first brake operable to hold one of the sun ' ',, ' ,: . , ', : ' ', ' ' :. ~-. . : "' ' ' . . ,. : ' ~ .

1i~)48~3 gears stationary; (4) a connection between the other sun gear and the output of the geared torque converter; (5) a second brake oper-able to hold the annulus gear stationary thus to enable forward and reverse rotation of the planet carrier to be obtained and; (6) a lock-up clutch for clutching together two members of the duplex epicyclic gearset to lock-up said gearset.
The geared torque converter will give at least one range of operation, normally at least two because a further lock-up clutch is normally provided between the turbine and the impeller to give a direct drive through the converter. The duplex epicyclic gearset will give the possibility of having high and low ranges and forward and reverse rotation. The high and low ranges will be given by the first brake and the lock-up clutch. When the first brake is operated to hold one of the sun gears stationary the planet carrier will be driven at planetary ratio. When the lock-up clutch of the duplex epicyclic gearset is operated the gearset is locked up and will give a direct drive through the gearset thus giving a higher range or higher set of ranges.
Preferably the geared torque converter is itself arranged to give a number of ranges, for example, two ranges and direct drive and the duplex epicyclic gearset will superimpose on these ranges a high and a low ratio. Reverse rotation of the planet carrier of the duplex epicyclic gearset is obtained by operation of the second brake to hold the annulus of said gearset stationary.
Preferably, the first brake is operable to hold the first sun gear stationary and the second sun gear is connected to the output of the geared torque converter. Preferably, also, the lock-up clutch is operable between the first and second sun gears.
The invention will now be described in detail by way of example with reference to the accompanying drawings in which:-1~488~3 Figures 1 to 5 are diagrams illustrating five differentembodiments of the invention; and Figure 6 is a diagram in tubular form illustrating various types of known geared torque converters which may be used in the invention.
Referring first to Figure 1, a torque converter is indicated generally at 10, a simple epicyclic gearset at 11 and a duplex epi-cyclic gearset at 12.
The torque converter comprises an impeller 14, a turbine 15 10 and a reaction member 16. The impeller 14 is connected to the input 17 and there is a direct drive clutch 18 between the turbine and the impeller. The reaction member 16 is connected to the annulus gear 19 of the epicyclic gearset 11 and the turbine 15 is connected to the sun gear 20 of the gearset 11. One of the planet gears is indicated at 21 and is carried by a planet carrier 22.
The duplex epicyclic gearset 12 comprises a first sun gear 23, a first set of planet gears, one of which is indicated at 24, and an annulus gear 25. The gearset 12 also includes a second sun wheel 26 ~
which is connected to the turbine 15 of the torque converter and the ~-20 sun gear 20 of the gearset 11 and a second set of planet gears, one of which is indicated at 27, which mesh with the sun gear 26 and the planet gears 24. The first and second sets of planet gears 24 and 27 are carried by a planet carrier 28 which provides the output of the combination.
A lock-up clutch 29 is provided between the two sun gears 23 and 26 and when operated it locks up the duplex gearset 12 so as to give direct drive through the gearset.
The combination is provided with a number of brakes. Thus there is a brake indicated at 29a for the planet carrier 22 of 19 30 of the gearset. There is a brake indicated at 31 for the first 3 :

. : - , . : , ~:, : .
.

1~8813 sun gear 23 and a brake at 32 for the annulus gear 25. In operation, the output of the geared torque converter, indicated at 33 may be driven from the input 17 in two ranges~ In the first range, the brake 29_ is engaged while the brake 30 and the lock-up clutch 17 are dis-engaged. In the second range, the brake 30 is operated while the brake 29a and the lock-up clutch 18 are disengaged. Direct drive can be obtained by engaging the clutch 18.
The output of the planet carrier 28 in each of the states of the geared torque converter can be varied by operation of the clutch 29 and the brake 31. When the clutch 29 is operated, the duplex gearset 12 is locked up and the planet carrier 28 will rotate at the same speed as the output 33. When the clutch 29 is disengaged and the brake 31 is engaged to hold the sun wheel 23 stationary then the planet carrier will rotate at a lower planetary ratio.
To obtain reverse, the brake 32 is operated while the clutch 29 and the brake 31 are disengaged.
It will be seen, therefore, that the duplex gearset 12 acts as an auxiliary on gear change arrangements with respect to the geared torque converter 10 and also gives the facility for reverse.
Referring now to Figure 2, the duplex epicyclic gearset is arranged as described in relation to Figure 1 and the same reference numerals have been used. However, in Figure 2 the torque converter is indicated at 39 and comprises an impeller 40 which is connected to the sun gear 41 of an epicyclic gearset 42, a reaction member 43 which is connected to the annulus gear 44 of the gearset 42 and a turbine 45 which is connected to the sun gear 26 of the gearset 12.
One of the planet gears of the gearset 42 is indicated at 46 and is ; carried on a planet carrier 47 which is associated with a brake 48.
The annulus gear 44 is associated with a brake 49 and there is a lock-up clutch 50 between the impeller 40 and the turbine 45.

1~)48~3 In this arrangement, the low range of the geared torque converter 39, 42 is obtained by applying the brakes 48 while the brake 49 and clutch 50 are released, the second range is obtained by applying the brake 49 while the brake 48 and clutch 50 are re-leased and the direct drive is obtained by locking up the torque converter by means of the clutch 50. The operating of the duplex gearset is as described in relation to Figure 1.
In Figure 3, again the duplex gearset 12 is the same as in Figures 1 and 2 and is indic~ted by the same reference numerals.
In Figure 3, the gearset of the geared torque converter is indicated at 51 and is placed in front of the torque converter which is in-dicated at 52. Thus the annulus 53 of the gearset 51 is connected to the impeller 54 of the torque converter, the sun gear 55 of the ; gearset 51 is connected to the turbine 56 and to the second sun gear 26 of the gearset 12. One of the planet gears of the gearset 51 is indicated at 57 and this is carried on a planet carrier 58 which provides the input and there is a lock-up clutch 59 between the planet carrier 58 and the turbine 56. The torque converter includes a reaction member 60 which is connected through a one way clutch 61 to a fixed abutment 62.
In this arrangement, the geared torque converter i.e. the first gearset 51 and the torque converter 52 only give one range andidirect drive. There is direct drive when the clutch 59 is en-gaged and an indirect range when it is not. The duplex gearset 12 operates as described above.
Referring now to Figure 4, this shows a further arrangement in which the geared torque converter comprises the torque converter 63 and a gearset 64. The torque converter comprises an impeller 65 which is connected to the input, a turbine 66 which is connected to the planet carrier 67 of the gearset 64 and a reaction member 68 ,, ' ~ ' ' ' 8813 ::
which is connected through a one-way clutch 69 to the sun gear 70 of the gearset 64. The annulus gear 71 of the gearset 64 is con-nected to the second sun gear 26 of the duplex gearset 12. One of the planet gears of the gearset 64 is indicated at 72. There is a lock-up clutch 73 between the impeller 65 and the turbine 66. As in Figure 3, the geared torque converter gives one indirect range when the clutch 73 is not engaged and direct drive when the clutch 73 is engaged. The duplex gearset 12 operates as described above.
Referring now to Figure 5, the torque converter is indicated 10 at 74 and comprises an impeller 75 which is connected to the input, a turbine 76 which is connected to the annulus gear 77 of the gear-set 78 and two reaction members the first of which, 79, is connected to the sun gear 80 of the gearset 78, and the second reaction member 81 is connected through a one-way clutch 82 to an abutment 83. One of the planet gears of the gearset 78 is indicated at 84 and is mounted on a planet carrier 85 which has associated therewith a brake 86.
The reaction member 79 has associated therewith a brake 87 and there is a lock-up clutch 88 between the turbine and the impeller.
The geared torque converted consisting of the torque converter 20 74 and the gearset 78 can be operated in two ranges and direct drive.
In the first range the brake 86 is engaged while the brake 87 and t clutch 88 are disengaged, in the second range the brake 87 is engaged ~, while the brake 86 and clutch 88 are disengaged and, in direct drive, the direct lock-up clutch 88 is engaged. The duplex gearset 12 op-erates as described above.
Figure 6 shows in tubular form various known types of geared ~ torque converter which can be associated with a duplex epicyclic - gearset such as 12 referred to above to give a geared torque con-verter and duplex epicyclic gearset in accordance with the present 30 invention. When used in this manner the output from the geared torque :

.....
~148813 converter will be connected to one of the sun wheels of the duplex gearset 12. The letters A, P and S as used in Figure 6 denote the annulus, planet and sun gears of the arrangements respectively and the letters I, T, R and C denote the impellers, turbines, reaction members and one way clutches of the arrangements. The arrangements shown in line X of Figure 6 are what are known as "input coupled", the arrangements shown in line Y gives a simultaneous input to out-put connection, and the arrangements shown in line Z are what are known as "output coupled".
~10 The use of a duplex epicyclic gearset in combination with a geared torque converter extends the range of operation of the geared torque converter without adding a larger number of parts to the com-bination. Thus it is only necessary to have two brakes, the brakes 31 and 32 and a single lock-up clutch 29. This saves the further clutch which would be required if two epicyclic gearsets were used in place of the duplex gearset. Moreover, the duplex gearset saves one annulus gear as compared with an arrangement in which two epi-cyclic gearsets are used in combination with a geared torque con-verter to give the flexibility of operation thereof.

." ~ .

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. The combination of:
(i) a geared torque converter;
(ii) a duplex epicyclic gearset comprising first and second co-axial sun gears, an annulus gear, a planet carrier carry-ing a first set of planet gears meshing with the first sun gear and the annulus gear and a second set of planet gears meshing with the second sun gear and with the planet gears to the first set;
(iii) a first brake operable to hold one of the sun gears stationary;
(iv) a connection between the other sun gear and the output of the geared torque converter;
(v) a second brake operable to hold the annulus gear stationary thus to enable forward and reverse rotation of the plan-et carrier to be obtained and;
(vi) a lock-up clutch for clutching together two members of the duplex epicyclic gearset to lock-up said gearset.

2. The combination according to Claim 1 in which the first brake is operable to hold the first sun gear stationary and the second sun gear is connected to the output of the geared torque converter.

3. The combination according to Claim 1 in which the lock-up clutch is operable between the first and second sun gears.

4. The combination according to Claim 1 in which the torque converter is arranged to give a number of ranges.

5. The combination according to Claim 4 in which the torque con-verter is provided with a further lock-up clutch between the tur-bine and impeller, said further lock-up clutch being arranged to give a direct drive when said first lock-up clutch is engaged.