FR2681118A1 - Automatic gear-change device with parallel shafts and double drop-down in gears, particularly for a motor vehicle - Google Patents

Abstract

Automatic gear change device with stepped ratios in particular for a vehicle comprising, inside a housing (18), a first input shaft or shaft 0 which receives the engine torque via a torque converter (1) and supports an epicyclic gear train (4) made up of several elements including a sun gear (3), a planet carrier (7) and a ring gear (5), a second shaft or output shaft (10) not coaxial with the first shaft (2), which receives the engine torque from it via a first or a second lowering of gears (16, 11; 17, 13) and at least one clutch (9, 12, 8 ) and immobilization means (14, 15) which control the various ratios, characterized in that a first element of the train (4) is always coupled, by a direct connection, with the engine and / or the converter torque (1).

Description

AUTOMATIC GEAR CHANGE DEVICE
WITH PARALLEL SHAFTS AND DOUBLE DESCENT
GEARS. ESPECIALLY FOR VEHICLE
AUTOMOTIVE.

The present invention relates to the technical field of automatic gearboxes with stepped ratios, comprising two parallel shafts and a double descent of gears from the first shaft to the second shaft, in particular for a motor vehicle, the different ratios of which are obtained by putting in action of hydraulic receivers such as clutches and brakes.

 it is known to use a simple or complex planetary gear mechanism for this purpose, and to have one or more clutches on the inputs of the train. According to this arrangement, illustrated in particular by patent application No. 91-07771 of the applicant, not published to date, the train is uncoupled from the engine and / or from the converter when no clutch is tightened.

The major problems associated with this type of gearbox are problems of space, noise and efficiency, due in particular to excessive speeds of rotation of the planetary gear elements, between them, or vis-à-vis the organs of ordered.

To overcome these drawbacks, the invention proposes a new architecture of an automatic gearbox with stepped ratios, and a particular arrangement of the hydraulic receivers with respect to the planetary gear.

This invention relates to an automatic gear change device with stepped ratios, in particular for a vehicle, comprising in a casing, a first shaft or input shaft which receives the engine torque via a torque converter and supports a train. epicycloidal consisting of several elements including a planetary, a satellite carrier and a crown, a second shaft or output shaft not coaxial with the first which receives the driving torque of the input shaft via a first or a second descent of gears, and at least one clutch and one immobilization means which control the various ratios. This device is characterized in that a first element of the train is always coupled, by a direct connection, with the motor and / or the torque converter.

According to one embodiment of the invention, a first and a second clutch make it possible to secure respectively a second and a third element of the planetary gear with the first and the second output of the movement from the first shaft to the second shaft, on the corresponding ratios.

According to one embodiment of the invention, the first and the third element of the planetary gear are connected by a third clutch, the tightening of which requires the planetary gear to turn in block on the corresponding ratios.

According to one embodiment of the invention, the first element of the planetary gear train is constituted by the planet gear thereof, while the second and the third element of the planetary gear train are constituted respectively by the planet carrier and the crown.

According to one embodiment of the invention, all of the clutches and of the immobilization means are carried by the first shaft.

According to one embodiment of the invention, the first and the second clutch are carried by the second shaft.

According to one embodiment of the invention, two immobilization means make it possible to immobilize respectively, relative to the casing, the satellite carrier and the crown, and to obtain in combination with the first, the second and the third clutch, four forward and one reverse gear.

According to one embodiment of the invention, the first forward gear ratio is obtained by tightening the first clutch and the second immobilization means.

According to one embodiment of the invention, the second forward gear ratio is obtained by tightening the first and the second clutch.

According to one embodiment of the invention, the third forward gear ratio is obtained by tightening the first and the third clutch.

According to one embodiment of the invention, the fourth forward gear is obtained by tightening the second and the third clutch.

According to one embodiment of the invention, the reverse gear is obtained by tightening the second clutch and the first immobilization means.

According to one embodiment of the invention, this device comprises a single immobilization means making it possible to immobilize the planet carrier relative to the casing and to obtain, in combination with the first, the second and the third clutch, three forward gears and a reverse gear, the control of which corresponds respectively to the second forward gear, to the third forward gear, to the fourth forward gear, and to the reverse gear, of a corresponding device comprising two means of immobilization.

The invention will be better understood on reading the following description of an embodiment thereof, in conjunction with the appended drawings in which - FIG. 1 schematically represents a first mode of
realization of a four-speed gearbox in accordance with
the invention, in which all the clutches and brakes are
carried by the input shaft; - Figure 2 schematically shows a variant of this box of
speeds, according to which two clutches are carried by the output shaft - Figure 3 is a diagram limited to the planetary gearbox of a gearbox
four forward gears; - Figure 4 is a diagram limited to the planetary gear train dtune
three forward gears; - the table in figure 5 indicates the functional combinations
corresponding to a four-speed automatic transmission
forward; - the table in figure 6 indicates the functional combinations
corresponding to a three-speed automatic transmission
forward.

In Figure 1, there is shown inside the housing 18 the torque converter 1 of the transmission, disposed on the first shaft 2 or input shaft of the automatic gear change device itself. This shaft 2, therefore receiving the engine torque (whether or not via the torque converter I) is directly coupled to the sun gear 3 of the simple planetary gear 4, further composed of the crown 5, the satellites 6 and the planet carrier 7.

Conventionally, the output shaft 10 drives, via its end pinion 19 and the gear 20, the differential 21 connected to the front axle 22 and to the rear axle 23 of the vehicle.

The sun gear 3 and the crown 5 can be joined in rotation by a clutch 8 called the third clutch (E3). The satellite carrier 7 is connected by a clutch 9, called the first clutch (El) to a first movement output 16 which itself is connected to the second shaft 10, by means of the gear 11.

The crown 5 is connected by the clutch 12, called the second clutch (E2) to a second movement output 17 of the shaft 2, itself connected to the second shaft 10, by means of the gear 13. The first descent of gears 16, 1 1 has a transmission ratio il, different from the transmission ratio i2, of the second descent 17, 13. Furthermore, the planet carrier 7 may be immobilized in rotation with respect to the casing 18 by the brake 14, called the first brake or first immobilization means (F1) while the crown 5 can be immobilized in rotation with respect to the casing 18 by the brake 15 called the second brake, or second means d 'immobilization (F2).

The operation of this four-speed forward gear change device, summarized by the table in FIG. 5, is as follows.

avec

si zp est le nombre de dents du planétaire 3 et Es celui de la couronne 5. L'embrayage (El) 9 permet la sortie du mouvement sur le second arbre 10, par l'intermédiaire de la première descente d'engrenagesl6, 11, la vitesse de rotation du second arbre 10 étant alors égale à

The first forward gear ratio is obtained by actuating the second brake (F2) 15 and the first clutch (E1) 9: the brake (F2) 15 immobilizing the crown 5 of the train 4, the sun gear 3 rotating at turbine speed wt of the converter 1 output, the planet carrier 7 will rotate at speed

with

if zp is the number of planetary teeth 3 and Es that of the crown 5. The clutch (El) 9 allows the movement to exit on the second shaft 10, by means of the first descent of gears 16, 11, the speed of rotation of the second shaft 10 then being equal to

The second forward gear ratio is obtained by actuating the first and second clutches (E1) and (E2), 9, 12, which by means of the first and second gear descent, 16, 11 and 17, 13, impose the ratio> -L between crown 5 and planet carrier 7 of the planetary gear, hence a speed of rotation of the secondary shaft 10, equal to

The third forward gear ratio is obtained by actuating the first and third clutches, (El) and (E3) 9, 8. The third clutch (E3) 8, blocks the train 4. The first clutch (El), 9 , allows the output of the movement on the second shaft 10, by means of the first descent of gears 16, 11. The second shaft 10 therefore rotates at speed

The fourth gear is obtained by actuating the second and third clutch (E2) and (E3) 12, 8. As in the third gear, the clutch E3, 8 blocks the train 4. The second clutch (E2), 12 allows the output of the movement on the output shaft 10, which therefore rotates at speed

Reverse is obtained by actuating the first brake F1 (14) and the second clutch (F2), 12. The first brake (FI), 14 immobilizing the planet carrier 7, the crown 5 rotates at speed * eJt K; by the second gear descent 17, 13, the output shaft 10 therefore rotates at speed

The automatic gearbox shown schematically in Figure 2 has the same number of actuators as that of Figure 1, namely three clutches (El), (F2), (E3) 9, 12, 8, and two brakes (F1) and (F2) 14, 15. These actuating members, here again making it possible to exploit the various combinations offered by the planetary gear 4 carried by the input shaft 2, and the two downspouts 16, 11; 17, 13 on the output shaft 10, however, are not arranged in the same way. In fact, the first clutch (El), 9, and the second clutch (F2), 12 are supported by the output shaft 10 and not by the input shaft 2. In this variant embodiment, these two members actuation 9, 12 respectively exercise the same functions as in the device of Figure 1, namely ensuring on the one hand for lt clutch (El), 9 a first movement output of the input shaft 2 from the planet carrier 5, by means of a first descent of gears 16, 11 and on the other hand, for the clutch (E2), 12, ensure a second exit from the movement of the input shaft 2 on the output shaft 10, by means of the second descent of gears 17, 13. The functional combinations indicated for the device in FIG. 1 and grouped together in the table in FIG. 5, therefore apply without modification , to this variant, the object of which is in particular to widen the possibilities of spatial arrangement of the device with regard to contra Internal dimensions inevitably imposed by the overall design of any vehicle.

The table in FIG. 6 indicates the functional combinations of an automatic gear change device with three forward gears. These combinations are obtained using three clutches (El), (E2), (E3) 9, 12, 8 and a single brake (F1) 14. Compared to "the box four" illustrated by Figures 1 and 2, this new variant simply corresponds to the removal of the second brake (F2) 15, therefore to the possibility of immobilizing the crown 5 with respect to the casing 18. This removal results in the abandonment of the first report of the gear change device with four forward gears, the three retained gears corresponding in this order to the second, third and fourth gear thereof.

Of course, this simplification of the device leading to a "three box" can be implemented effectively only at the price of a new stepping of the three forward ratios retained, different from that of the three upper ratios of the " box four ". FIGS. 3 and 4 are intended to illustrate the structural modifications corresponding to this reordering of the ratios. These figures respectively represent the epicyclic train of the "box four" and the "box three": in Figure 4 we observe that the crown 5 is larger than in Figure 3. Indeed, the removal of the second brake (F2 ) 15, freeing up space in the casing 18, in particular makes it possible to enlarge the diameter of the crown 5; by keeping the same satellite carrier 7, it is possible to adopt larger satellites 6 and therefore a smaller sun gear 3, in order to obtain a first gear (corresponding to the tightening of the first and second clutch (El), (E2) 9, 12 ) smaller.

This modification has no influence on the two upper ratios because the tightening of the third clutch (E3) 8, requires the planetary gear 4 to turn as a unit on these two ratios, both in the case of the "four box" and in that of the "box three".

The rotation "en bloc" of the planetary gear 4 on the two upper ratios, (which are the most used, in the case of a "four box" as in that of a "three box"), putting in a way the train "out of service" on these reports, considerably reduces the number of gears, used to ensure the transmission of torque on them.

 The main result of this is a very marked improvement in the efficiency of the transmission, as well as a reduction in the noise emitted by it, which is extremely appreciable for the user of the vehicle.

Claims (13)

CLAIMS torque converter (1). coupled, by a direct connection, with the engine and / or characterized in that a first element of the train (4) is always (14, 15) which ensure the control of the different ratios, and at least one clutch (9, 12, 8) and a means of immobilizing first or a second descent of gears (16, 11; 17, 13) (2), which receives the driving torque of the latter via a second shaft or output shaft (10) not coaxial with the first shaft a planet (3), a satellite carrier (7) and a crown (5), a planetary gear (4) made up of several elements 3, 5, 6, 7) of which by means of a torque converter (1) and supports a first shaft or input shaft (2) which receives the engine torque in particular for a vehicle comprising, inside a casing (18),  1 ") Automatic gear change device with stepped ratios  second tree (10), on the corresponding reports.  second movement output (16,; 17,) from the first shaft (2) towards the  element (7, 5) of the planetary gear (4) with the first and the  allow to join a second and a third respectively  characterized in that a first and a second clutch (9, 12)  2 ") gear change device according to claim 1,  on the corresponding reports.  the tightening of which requires the planetary gear (4) to turn in a block  planetary gear (4) are connected by a third clutch (8),  characterized in that the first and the third element (3, 5) of the  3 ") gear change device according to claims 1 or 2,  planet carrier (7) and the crown (5).  third element of the planetary gear train (4) are respectively the  epicyclic (4) is the planetary (3), while the second and the  1, 2 or 3, characterized in that the first element of the train  4) gear change device according to one of claims  carried by the first shaft (2).  clutches (9, 12, 8) and immobilization means (14, 15) is  previous claims, characterized in that all of the  5) Gear change device according to any one of  clutch (9, 12) are carried by the second shaft (10).  Claims 1 to 4, characterized in that the first and the second  6) Gear change device according to any one of  forward and reverse gear.  and the third clutch (9, 12, 8), four gears  crown (5), and to obtain in combination with the first, the second  respectively with respect to the casing (18) the satellite carrier (7) and the  immobilization means (14, 15) for immobilizing  previous claims, characterized in that it comprises two  7) Gear change device according to any one of  immobilization (15).  by tightening the first clutch (9) and the second means  characterized in that the first forward gear is obtained  8) gear change device according to claim 7,  by tightening the first and second clutch (9, 12).  characterized in that the second forward gear is obtained  9) gear change device according to claims 7 or 8,  obtained by tightening the first and third clutch (9, 8).  9, characterized in that the third forward gear is  10) gear change device according to claims 7, 8 or  clutch (12, 8).  forward movement is obtained by tightening the second and third  claims 7 to 10, characterized in that the fourth gear ratio  11 ") Gear change device according to any one of  immobilization means (14).  obtained by tightening the second clutch (12) and the first  Claims 7 to 11, characterized in that the reverse gear is  12 ") Gear change device according to any one of  comprising two immobilization means (14, 15).  forward and reverse of a corresponding device  forward, third gear forward, fourth gear  command corresponds respectively to the second gear ratio  forward reports and a reverse report the  with the first, second and third clutch (9, 12, 8) three  satellite (7) relative to the casing (18), and to obtain, in combination  immobilization means (14), which immobilizes the door  Claims 1 to 6, characterized in that it comprises only one  13) Gear change device according to any one of