FR2503308A1 - Motor vehicle automatic transmission - uses solenoid valve to hydraulically select either torque converter or clutch as drive coupling - Google Patents

Abstract

The automotive transmission has a hydraulic coupling (12), for example a torque converter, in parallel with a clutch (13). Under the control of hydraulic actuator (24), either the clutch or the hydraulic coupling is engaged. A slide valve (29) is used to ensure alternate operation of the clutch and the hydraulic coupling, and the operation of the slide valve is controlled by an electromagnet. The core (58) of the electromagnet (59) is integral with the slide valve, so when the electromagnet coil is energised the slide valve is positioned to supply hydraulically one of the coupling paths while obstructing the hydraulic supply to the other. The operation of the electromagnet is controlled by a circuit (50) which responds to speed, throttle setting and other parameters so the clutch is disengaged during gear changes.

Description

 The present invention relates generally to transmissions with hydraulic coupling member and locking clutch, that is to say transmissions of the type comprising, in parallel between an input element intended to be secured in rotation to a first shaft, in general a driving shaft, and an output element intended for other secured in rotation to a second shaft, in general a driven shaft, on the one hand a hydraulic coupling member, such as torque converter or coupler , which comprises an impeller wheel integral in rotation with the input element and a turbine wheel integral in rotation with the output element, and on the other hand a clutch, which comprises a coupling element mounted movably axially, said coupling element being integral in rotation with the output element and capable of stretching secured in rotation, by friction, to the input element.

 It relates more precisely to those of these transmissions which are intended for the equipment of motor vehicles.

 They can be semi-automatic transmissions as well as automatic transmissions.

 In both cases, with such a transmission, there is usually associated a hydraulic control with reversing slide suitable for alternating commissioning either of the hydraulic coupling member or of the clutch: at start-up, and generally but not necessarily, at each change of speed ratio, the clutch is, at first, ineffective, and therefore lets the hydraulic coupling member intervene between the input element and the output element; then, in a second step, the clutch comes to deactivate the hydraulic coupling member, to then remove the slip dfl thereto and therefore improve the performance of the assembly, by ensuring a direct mechanical coupling between the input element and output element.

 A transmission of this type is found in particular in the French patent application filed on April 2, 1979 under No. 79 08192 and published under No. 2,453,335.

 Most often, the hydraulic control reversing slide associated with such a transmission is itself hydraulically controlled, from the pressure coming to prevail in selected regions of the hydraulic coupling member, or of the transmission itself.

 It frequently results in a certain complexity and difficulties.

 However, it turns out that at least on certain vehicles, there is also associated with transmissions of the type concerned an electro-mechanical control which, sensitive to various information, such as speed of rotation at the output shaft of the gearbox. speeds, position of the gearshift lever, load and speed of the motor, or the like, is capable of delivering consequently, or not, an electrical signal on at least one output, for control, consequently, or not, of a gear change.

The present invention generally aims to take advantage of the signal thus available to ensure, depending on the configuration of the assembly, the control of the reversing slide of the hydraulic control.
More specifically, the subject of the present invention is a transmission, in particular for a motor vehicle, of the type comprising, in parallel between an input element, intended for another secured in rotation to a first shaft, generally a driving shaft, and an output element, intended to be secured in rotation to a second shaft, in general a driven shaft, on the one hand a hydraulic coupling member, such as a torque converter or coupler, and on the other hand a clutch, in cooperation with a hydraulic control with reversing slide suitable for alternating commissioning, either of the hydraulic coupling member or of the clutch, this transmission being characterized in that said reversing slide is controlled by electromagnetic control.

 In practice, this reversing slide is coupled to the movable core of an electromagnet, and the latter is controlled by the usually associated electromechanical control.

 This results in a significant simplification of the assembly and a high level of operational reliability.

The characteristics and advantages of the invention will emerge from the following description, by way of example, with reference to the appended schematic drawings in which
FIG. 1 is a block diagram of a transmission according to the invention, when the hydraulic coupling member which the latter comprises is in service,
Figure 2 is a view similar to that of Figure 1, when the clutch that comprises the transmission according to the invention is in turn in service.

The transmission to which the invention applies being well known in itself, and being in particular described, at least for its essential elements in the French patent
No. 79 08192 mentioned above, it has only been shown schematically in the figures, and it will only be described briefly below.

It comprises, overall, in parallel between an input element 10, intended to be secured in rotation to a first shaft, in general a driving shaft, and formed, in the exemplary embodiment shown, by the rotating casing of the assembly, and an output element 11, intended to be secured in rotation to a second shaft, in general a driven shaft, and formed, in this embodiment, by a tubular hub, on the one hand a member of hydraulic coupling 12, and on the other hand a clutch 13
In the embodiment shown, the hydraulic coupling member is a torque converter, which comprises an impeller wheel 15, integral in rotation with the input element 10, a turbine wheel 16, integral in rotation of the output element 11, and, between this impeller wheel 15 and this turbine wheel 16, a reactor wheel 17.

 Jointly, the clutch 13 comprises a coupling element 18, which is mounted axially movable, and which, soli; rotation of the output element 11, is capable of being secured in rotation, by friction, to the input element 10, by cooperation with the corresponding transverse wall of the rotary casing forming this input element 10 in the embodiment shown.

For example, and as described in the French patent
No 79 08192 mentioned above, the rotational connection of the coupling element 18 with the output element 11 can be ensured by means of a damping hub 20, one of the rotary parts of which is integral in rotation of this output element 11, while the other is coupled to the coupling element 18 by a tongue connection allowing the axial mobility thereof.

 Anyway, in the rotary casing forming one input element 10, two distinct regions are defined, one, 22, inside the clutch 13, between the coupling element 18 thereof. ci and the corresponding transverse wall of said rotating casing, the other, 23, external to this clutch 13.

 With the transmission thus formed, there is associated, in cooperation, a hydraulic control 24 suitable for alternating commissioning, either of the hydraulic coupling member 12 or of the clutch 13.

 This hydraulic control 24 includes a pump 26, preferably that of the transmission, the suction line 27 of which plunges into a tank 28 to contain fluid, and the discharge line 32 of which, in addition to other members not explained here, supplies , under the control of an inversion drawer 29, either the region 22 of the rotating casing formed by the input element 10, by a pipe 30, or the region 23 of this rotating casing, by a pipe 31.

 The reversing slide 29 is mounted movably in a body 33, against a spring 34, and has two bearing surfaces 35, 36 delimiting between them a chamber 37 which a pipe 38 connects to the delivery pipe 32 of pump 26.

 The bearing surface 35 has annularly a groove 45 which a passage 39, which, according to the invention, forms or comprises a throttling nozzle, makes communicate with a chamber 40 in connection, by a pipe 41, with a pipe 42 suitable for ensure, as will appear below, a return to the cover 28 of the fluid used.

 The range 36 conditions the connection, or not, by a chamber 43, of the pipe 31 with a pipe 44 also connected to the return pipe 42, at the junction of the latter with the pipe 41.

 On this return pipe 42 is interposed a throttling nozzle 46, and, likewise, on the pipe 38 serving the body 33 is interposed, upstream of it, a throttling nozzle 47.

 The transmission in question is also associated with an electromechanical control 50, which, well known in itself, and not part of the present invention, will not be described in detail here.

 This electromechanical control 50 is sensitive to various information, such as position of the gear shift lever 51, speed of rotation of the output shaft of the gear boot, by an appropriate member 52, and load of the motor, by a member appropriate 53, and is able to deliver accordingly or not, an electrical signal on at least one output which can also allow the gear boot to change gear.

 In practice, and in a manner known per se, two outputs 54, 55 are provided, one of positive polarity, the other of negative polarity.

 According to the invention, the reversing slide 29 of the hydraulic control 24 is controlled by an electromagnetic control.

 In the embodiment shown, it is for this purpose, coupled by a rod 57 to the movable core 58 of an electromagnet 59 which constitutes said electromagnetic control.

 According to the invention, the latter is controlled by the electromechanical control 50, its terminals being connected to the outputs 54, 55 of the latter by a wiring 60.

 The arrangements described above are such that, for certain given preferred configurations of the assembly, and more specifically of the electro-mechanical control 50, the electromagnet 59 is not excited, no electrical signal appearing on the outputs 54, 55 of this electromechanical control 50.

 This is the case, in particular, at start-up, but this can also be the case for example when, for the "automatic position of the lever 51, the first gear is engaged, or when the gearbox changes gear.

 In such a case, and under the stress of the spring 34 which is associated with it, the reversing slide 29 occupies a position for which, as shown in FIG. 1, the region 22 of the rotary casing 10 is in connection with the delivery of the pump 26, through, successively, the pipe 32, the pipe 38, the chamber 37, and the pipe 30, while the region 23 of this rotary casing 10 is jointly connected with the cover 28, by, successively, the pipe 31, the chamber 43, the pipe 44, and the pipe 42.

 The pressure in region 22 of the rotating casing formed by the input element 10 is therefore greater than that in region 23 thereof, the coupling element 18 of the clutch 13 is separated from the corresponding transverse wall of this rotating casing and, as a corollary, the hydraulic coupling element 12 is in service.

 As is easy to understand, the throttle nozzle 46 is determined so as to then ensure a suitable pressure inside the hydraulic coupling member 12, while the throttle nozzle 47 is determined so as to ensure a suitable pressure at the outlet of the pump 26.

 For other configurations of the assembly, and more precisely of the electromechanical control 50, the electromagnet 59 is excited, electrical signals appearing appropriately on the outputs 54, 55 of this electromechanical control 50.

 This can be the case for example when, the lever 51 being in the "automatic" position, a speed of a row greater than the first is engaged, or when, for a given loading condition, the vehicle reaches a certain speed.

 This can also be the case when, for a determined position of the lever 51, the first speed is imposed, or when, for any position of the lever 51, any speed of a row greater than a determined row is engaged.

 In this case, the movable core 58 of the electromagnet 59 is the object, according to arrow F in FIG. 2, of a repulsion force which results, against the spring 34, in the displacement of the reversing slide 29 in the direction of the position for which, as illustrated in this FIG. 2, the region 22 of the rotating casing formed by the input element 10 is connected to the cover 28, successively by the pipe 30 , the passage 39 of the bearing surface 35 of the reversing slide 29, the chamber 40, the pipe 41, and the pipe 42, while, as a corollary, the region 23 of this rotary casing is connected to the delivery pipe 32 of the pump 26, through, successively, the pipe 38, the chamber 37, and the pipe 31.

 The pressure in region 22 of the rotating casing formed by the input element 10 is therefore lower than that in region 23 thereof, the coupling element 18 of the clutch 13 comes to be pressed against the corresponding transverse wall of this rotating casing, so that a direct mechanical connection is ensured between the input element 10 and the output element 11, through the damping hub 20.

 The clutch 13 being thus put into service, it short-circuits the hydraulic coupling member 12.

 As is easy to understand, the throttle nozzle 39 appropriately modulates the commissioning of the clutch 13 when the latter is controlled.

 Of course, the present invention is not limited to the embodiment described and shown, but encompasses any variant.

 In particular, instead of being coupled to an electromagnet, the reversing slide used can be controlled by an electro-valve, which constitutes the associated electromagnetic control.

Claims (5)

 1) Transmission, especially for motor vehicles,  of the kind comprising, in parallel between an input element  (10), intended to be secured in rotation to a first ar  bre, in general a driving shaft, and an output element (11),  intended to be secured in rotation to a second shaft, in  general a driven shaft, on the one hand a coupling member hy  hydraulics (12), such as torque converter or coupler,  and on the other hand a clutch (13), in cooperation with a  hydraulic control (24) with reversing slide (29) suitable for  alternate commissioning of either the coupling member  hydraulic (12), either of the clutch (13), characterized in  that said reversing drawer (29) is controlled by a com  electromagnetic control.  2) Transmission according to claim 1, characterized  in that the reversing slide (29) is coupled to the mcbile core  (58) of an electromagnet (59) which constitutes the control thereof  electromagnetic.  3) Transmission according to claim 2 characterized  in that the reversing drawer (29) is controlled by an electric  trovalve which constitutes its electromagnetic control.  4) Transmission according to any one of the claims  2, 3 and to which, in the case of a transmission for  motor vehicle, it is associated with an electromechanical control (50), sensitive to various information such as  speed of rotation of the gearbox output shaft, position of the gearshift lever, load and speed of the motor, or the like, and suitable for delivering, or not, an electrical signal on at least one output (54, 55), characterized in that said electromagnetic control is controlled by said electromechanical control (50).  5) Transmission according to any one of claims 1 to 4, wherein the reversing slide (29) has a passage (39) ensuring, when the commissioning of the clutch (13) is controlled, a return to the deer (28) of the corresponding fluid, characterized in that said passage (39) forms or comprises a throttling nozzle.