MXPA06005218A - Multi-speed transmission device particularly for motor vehicles - Google Patents

Abstract

The transmission device (1) comprises two power trains (8a, 8b), arranged in parallel, permanently connected to the input shaft (2) from the engine (3) and the output shaft (4) for driving the differential (6). In each power train (8a, 8b), each ratio (Ia, IIa, IIIa or Ib, IIb, IIIb), is achieved by the operation of a single actuator which can match the speed of rotation of the shafts (2 and 4) on changing ratio. A controller (17) synchronizes the activations/deactivations on changing ratio, such that the next ratio is either in the same train or in another train.

Description

DEVICE FOR TRANSMISSION OF MULTIPLE SPEEDS PARTICULARLY FOR AUTOMOBILES DESCRIPTION OF THE INVENTION This invention relates to a multiple gear ratio transmission device for connecting a motor to a load such as a motor vehicle. A transmission device of this type is known in which an upper shaft, connected to the motor, can be selectively connected to one of two countershafts by means of one or the other of two clutches. Each countershaft has intermediate gears with different diameters, with which the countershaft can be selectively coupled by means of claw coupling or synchronization devices. These intermediate gears are permanently geared to the gears attached to a secondary shaft, which is shared by the two countershafts. During the operation, a single intermediate gear is coupled to each countershaft, but one of the two countershafts does not transmit any energy while rotating independently of the motor due to the uncoupling of its input clutch. To change the gear ratio, the controls couple or keep coupled to the countershaft disabled, the intermediate gear corresponding to the new gear ratio, and then the controls open the REF. 172591 input clutch previously active and close the input clutch previously inactive, which simultaneously varies the speed of rotation of the engine to adapt it to the speed of rotation of the tires of the vehicle according to the new gear ratio. This device, recently installed in standard production vehicles, has been considered as an anticipated step for the user as the synchronization time of the intermediate gear that has to be coupled or synchronized with its countershaft is no longer part of the period during which the transmission of energy between the engine and the tires of the vehicle is interrupted. However, it is believed according to the invention that this advantage is obtained at the cost of excessive disadvantages. In particular, the device requires two input clutches instead of just one, two countershafts, highly complex control, greater axial length of the device with almost no flexibility in terms of spatial design, very large weight and prohibitive cost. On the other hand, the known device does not directly allow the change between two gear ratios that are defined by the intermediate gears carried by the same countershaft. In addition, in the field of conventional automatic transmissions, that is, comprising an axial series of planetary gear trains, the most recent transmissions exhibit an increased number of gear ratios, with up to seven gear ratios currently available. This type of transmission also creates a problem of size, weight, complexity, cost and difficulty of installation in certain types of vehicles, particularly front-wheel transmission vehicles and especially vehicles with transverse engines. The object of this invention is at least partially rectify these disadvantages and thus propose a transmission device that can be simpler to design and / or control, less bulky and / or easy to configure in space, easy to automate and with more control flexible. According to the invention, the multiple gear ratio transmission device adapted to connect a motor to a load such as a motor vehicle comprises: - an upper shaft, - a lower shaft, - connected to each other by at least two trajectories of energy that define different gear ratios, - in each energy path, the selective actuators for each determined gear ratio, characterized in that: - the connection between the upper shaft and a respective input unit of each of the trajectories of energy is permanent; and - the selective actuators are of a gradual type and / or capable of adapting the motor speed to the loading speed. According to the invention, the function to activate the gear ratio and the function to adapt the speeds of the upper shaft and lower shaft of the transmission device are grouped together in a single selective activator. Thus, there is now only one connection that is activated for all energy paths at all times, in contrast to the prior art device, in which two connections were made on two different countershafts, but with only one connection being validated by a relevant one of the two input clutches. According to the invention, the control sequence is simplified and corresponds to a normal sequence in the known automatic transmissions, normally with the deactivation of a friction clutch such as a brake or a clutch and a synchronized activation of another friction coupling. On the other hand, according to the invention, it is irrelevant whether the new gear ratio is obtained in the same energy path as the previous gear ratio or in another trajectory. Other features and advantages of the invention will become apparent from the following description, which relates to the non-exhaustive examples. In the attached figures: Figure 1 is a block diagram of the transmission device according to the invention; - figure 2 is a block diagram similar to figure 1, but with some additional details; - Figure 3 is a general schematic view of an example of a transmission device according to the invention; - Figure 4 is a schematic end view of the device in Figure 3; and - Figure 5 is a diagram of another embodiment of the device according to the invention. In the example shown in figure 1, the transmission device 1 is operatively mounted between an upper shaft 2, which in the example is the energy axis of an automobile engine 3, and an ex and lower 4, which in the example it is shown as the input shaft in a differential 6, the output shafts of which are the tire axles 7 of the vehicle.

The transmission device 1 connects the upper shaft 2 to the lower shaft 4 by two energy paths 8a, 8b mounted mechanically in parallel. There is a permanent mechanical connection between the upper shaft 2 and a rotary input unit 9a of the trajectory 8a, and between the upper shaft 2 and a rotary input unit 9b of the trajectory 8b. Similarly, a rotary output unit Ia of the path 8a and a rotary output unit llb of the path 8b are permanently and mechanically connected to the lower shaft 4. In the example shown in FIG. 1, these permanent connections are made by a gear 12 joined to the upper shaft 2, which is engaged with the input gears 13a, 13b rotatably connected to the input unit 9a and 9b respectively, and by a gear 14 which is attached to the lower shaft 4 and which meshes with the gears of output 16a, 16b attached to the output unit lia and llb, respectively, for the common rotation therewith. In the example shown, the input gears 13a and 13b have different diameters so that the transfer ratio between the upper shaft 2 and the input unit 9a in the first energy path 8a is different from the transfer ratio between the upper shaft 2 and the input unit 9b in the second energy transmission path 8b. Reciprocally, the. Output gears 16a and 16b have the same diameter. This solution allows for different gear ratios to be obtained. in the first energy path 8a and the second energy path 8b even if they are identical as suggested by the example shown in Fig. 1. However it will be seen below that the specific characteristic in relation to the different transfer relationships is also of interest in situations where the two energy transmission trajectories are not identical. As a variant, the input gears 13a, 13b can have identical diameters and the output gears 16a, 16b can have different diameters. It is also possible that the input gears and the output gears have different diameters. Figure 1 shows, by analogy with a multiple position electrical switch, that each of the energy transmission paths 8a and 8b offers the possibility of choosing between three different gear ratios marked as the, bund, Illa and a neutral Na , and Ib, Ilb, Illb and Nb respectively. The gear ratio between the input and output of a power transmission path 8a or 8b hereinafter is referred to as the "local gear ratio". The gear ratio of the transmission device in a given operating state corresponds to the local gear ratio in the path 8a or 8b that is not in a neutral position, as modified by the upper transfer ratio created by the upper gear 12 with the input gear 13a or 13b and the lower transfer ratio created by the output gear 16a or 16b with a lower gear 14. The local gear ratios of the two trajectories 8a, 8b can be identical from a trajectory a the other, because the total gear ratios will still be different due to the different transfer relationships. In particular, the two energy transmission paths 8a and 8b can both have, as one of their local gear ratios, a direct transmission ratio. The two energy transmission paths 8a, 8b are subjected to a shared control device 17 which synchronizes the gear ratio changes in the two energy transmission paths 8a, 8b. In the same schematic diagram in Figure 1, the control device 17 acts on a selective trigger 18a of the path 8a and 8b of the path 8b. Taking the example of the trajectory 8a, the activator 18a selectively connects the input unit 9a with one of the three mechanical trajectories, Illa, which leads to the output unit lia with a different local gear ratio, or with the neutral position Na corresponding to the transmission cut-off between the input unit 9a and the output unit lia. The selective trigger 18b has the same function in the path 8b as only described for the trigger 18a, providing that the suffixes (a) of the reference numbers are replaced by the suffixes (b). The operation of the device according to the invention will now be described in the same general example of Figure 1. To put the transmission device 1 in neutral, the two activators 18a and 18b are in their neutral positions Na and Nb respectively. To connect the upper shaft 2 with the lower shaft 4 with a total gear ratio corresponding to one of the possible sixes, the activator 18a or 18b of the path 8a or 8b with which the required gear ratio is associated, is placed in the required position, for example, in the operation example in figure 1 in the trajectory 8a, while the activator, 18b in the example shown in figure 1, of the other transmission path, 8b in the same example, place in its corresponding neutral position Nb. Thus, in the example, the energy that is transmitted via the transmission path 8a with the required total ratio of the path 8b is inactive.

As will be seen in the more specific examples below, each selective actuator 18a or 18b is not simply a stop or synchronizer, which will only be capable of coupling or uncoupling without any load, but a coupling, usually a friction coupling and more particularly a coupling wet multi-disc, able to modify the speed of rotation of the motor shaft according to the speed of rotation of the tires of the vehicle during changes in the gear ratio, and also capable, of at least one gear of start of the vehicle (for example the), start the rotation of the lower shaft 4 and therefore the forward movement of the vehicle from a situation in which the vehicle is stationary. During a change in the gear ratio, the new gear ratio to be normally coupled corresponds to the neutral positioning of the energy transmission path that was initially active, and the activation of a gear ratio in the energy path that was initially neutral. The control device 17 synchronizes the activation of the two activators 18a, 18b to minimize the jolts and the period during which the transmission of energy to the tires of the vehicle is interrupted. If necessary, the control device can also be connected to the electronic control system of the motor 3 to regulate the power of the motor during the process of changing the gear ratio. It is also possible that a gear ratio change process consists of the change from one local gear ratio to another in the same power transmission path, with the other power transmission path remaining in neutral. The example shown in Fig. 2 differs from the example shown in Fig. 1 only in that the selective actuators 18a and 18b have been replaced by a specific activator for each local gear ratio that can be obtained, i.e. 118a, 218a, 318a, 118b, 218b, 318b. These triggers are shown as couplers, even as an example. The neutral is not shown as large as that obtained by placing the three selective activators in the same energy transmission path, for example 8b in the example shown, in a decoupled state. The control device 17 determines the state of each of the selective triggers so that when the vehicle is running, one of the selective activators is always in a coupled state and all the others are in a decoupled state, with the changes of the gear ratio that are achieved by decoupling the trigger that was hitherto coupled, and exchanging another of the triggers that was previously decoupled to a coupled state, in a synchronized manner. The deactivation of the "old" activator can be progressive during the progressive activation of the "new" activator in a sense that the driver of the vehicle will not feel any interruption in the transmission of energy to the tires of the vehicle. In the two examples just described, and in the following examples, the two energy transmission paths 8a and 8b are kinematically independent of each other, apart from of course the fact that their input units 9a, 9b mesh with the same upper gear 12 and its output units lia, llb are meshed with the same gear 14 on the lower shaft 4. This specific feature distinguishes the invention from the prior art transmission device, in which both energy paths pass through of the same secondary axis. In the example shown in Figure 3, each energy transmission path 8a or 8b comprises a planetary gear train mechanism, for example of the type that will be described in detail below with reference to Figure 5. In this example, advantage is taken of the possibility offered by this type of mechanism to place the output gears 16a, 16b at a distance from the spatial end 19a, 19b of the mechanism. This is advantageous in certain installation scenarios of the gearbox assembly of the engine in which the distance between the front end of the engine (left end not shown in Figure 3) and the output site of the transmission device should be reduced to minimum. Figure 4 illustrates the possibility of having in the corners of a quadrilateral the driving shaft or upper shaft 2, the lower shaft 4 diagonally opposite, and the two geometric axes 21a and 21b, also diagonally opposite, of the two trajectories 8a and 8b. Fig. 5, only the upper half of the trajectory 8a and the upper half of the trajectory 8b can be considered. In this embodiment, trajectories 8a and 8b have a differentiated structure to allow a better spacing of the gear ratios of the transmission device as a whole. In the example shown in Figure 5, the energy path 8a comprises about a single shared axis 21a in a housing 22 (partially shown), a first planetary gear train 123a and a second planetary gear train 223a, comprising respectively: first and second planetary carriers 124a, 224a, first and second solar gears 126a, 226a, first and second internal ring gears 127a, 227a.

The planet carriers 124a, 224a rotatably maintain the satellite pinions 128a, 228a which are eccentric relative to the general axis 21a, and each of which meshes with the corresponding sun gear 126a or 226a and corresponding ring gear 127a or 227a. The first planetary carrier 124a is attached to the input unit 9a and the second sun gear 226a. The output unit lia is attached to the second planetary carrier 224a and the first ring gear 127a. Selective activators comprise: a brake 118a associated with the second ring gear 227a, to selectively immobilize the ring gear. - a clutch 218a joining the second planetary carrier 224a and the second sun gear 226a, one connected to the output unit lia and the other to the input unit 9a; and - a brake 318a for selectively locking the first sun gear 126a, thereby imparting to the first ring gear 127a and thus to the output unit lia a speed which is multiplied by a certain gear ratio on the speed of the input element 9a. The output lia and its output gear 16a are located between, on the one hand, the two planetary gear trains 123a, 223a and, on the other hand, the selective coupling 218a. The output unit lia is tubular and surrounds an axis 29a connecting the clutch 218a with the second sun gear 226a. It can be seen from the figure that the output lia will have to be placed between the planetary gear trains, or the first ring gear 127a will have to extend to the right beyond its current end 31a, in order to carry the gear there outlet 16a which will then be axially juxtaposed with the input gear 13a near an axial end of the path. The selective actuators 118a, 218a, 318a are activated by the hydraulic pistons 32 (see activator 318a) which are annular about the general axis 21a, and behind which an annular chamber 33 for the pressurized oil is formed, on the remote side of the discs 34. For the two actuators 218a and 318a, which are brakes, the pressurized oil is carried in the corresponding chamber 33 through the conduits 36 of the housing. For the activator 218a, which is a clutch, the pressurized oil will arrive in the corresponding chamber (not shown) through a conduit (not shown) formed in the shaft 29a. With the general architecture that has just been described, the first local gear ratio, which is a local reduction ratio, is obtained by activating the brake 118a, thus immobilizing the second ring gear 227a, and the energy is transmitted from the power unit. input 9a to the output unit lia by the second gear train _ planetary 223.a. The brake 318a and the clutch 218a are released and the gears 126a, 127a, 128a of the first planetary train 123a are at idle. To obtain the second local gear ratio, which is a local direct drive gear ratio, the two brakes 118a, 318a are decoupled and the clutch 218a is engaged, so that the energy is transmitted by the clutch 218a from the input 9a to the exit Ia while all the planetary gears 126a, 127a, 128a, 226a, 227a, 228a are at idle. For the third local gear ratio, the clutch 218a is decoupled and the brake 318a engages, with the brake 118a still disengaged. The first solar gear 126a is now immobilized and the energy is transmitted from the input unit 9a to the output unit lia by means of the first planetary gear train 123a which operates as an overdrive gear, i.e. a gear which causes the unit The output will rotate at a higher speed than the input unit 9a. The gears 226a, 227a, 228a of the second planetary gear train 223a are at idle. The path 8b also contains two planetary gear trains 123b and 223b, but the planetary pinions are mounted in pairs 128i and 128e, 228I and 228e, each pair forms a mechanical series between solar gear 126b or 226b and ring gear 127b or 227b. The two ring gears 127b and 227b are joined to each other and to the output unit llb. The first planetary carrier 124b is attached to the input unit 9b and the second sun gear 226b. To obtain the first local gear ratio, a brake 118b selectively immobilizes the first sun gear 126b. To obtain the second local gear ratio, a brake 218b selectively immobilizes the second planetary carrier 224b. To obtain the third local gear ratio, which is a direct drive gear ratio, a clutch 318b selectively connects the input unit 9b and the output unit llb to each other. With this transmission device, and with a more reductive transfer ratio between the upper shaft 2 and the input unit 9a in the first path 8a between the upper arm 2 and the input unit 9b in the second path 8b, obtains the following combination, for example: first total gear ratio with the first local gear ratio of the first trajectory 8a; - second total gear ratio with the first local gear ratio of the second trajectory 8b; - third total gear ratio with the second local gear ratio of the second trajectory 8b; - fourth total gear ratio with the local direct driver of the first path 8a; - fifth total gear ratio with the local direct driver of the second trajectory 8b; and - sixth gear ratio with the third local gear ratio (overdrive) of the first path 8a. In this embodiment, the two planetary gear trains 123a, 223a and the clutch 218a of the path 8a are three energy sub-planes which are operative in parallel and activated alternately between the input element 9a and the output element lia. Similarly, the two planetary gear trains 123b, 223b and the clutch 218b of the second path 8b are three sub-planes operatively arranged in parallel between the input element 9b and the output element 11b. Each sub-trajectory is activated and deactivated the coupling and decoupling, respectively, of a single coupling means.

The structure of a transmission device with three sub-planes such as two planetary gear trains and a clutch, in which each gear ratio of the overall structure is obtained by activating a single selective coupling is particularly advantageous in the context of the invention as the The control of each energy path 8a or 8b is thus considerably simplified, which also simplifies the synchronization of the controls applied to the two paths 8a and 8b. More particularly, in order to exchange one gear ratio to another, an actuator such as 118, 218 or 318 must simply be decoupled, and the other activator must be activated simply, in the same path or in another path. Of course, the invention is not limited to the examples described and shown. Provision may be made for more than two power transmission paths. For example, a third path can be made from a direct drive between the upper shaft 2 and the lower shaft 3. Equal trajectories 8a and 8b can be produced, but even easier to control with only one brake for each local gear ratio that is, without any clutch. However, as the braked unit will act systematically as a reaction member coupled by another gear unit, where there is no longer a direct direct drive gear ratio.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (14)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. Device for transmission of multiple gear ratio, adapted to connect a motor to a load such as a car, characterized in that it comprises: - an upper shaft , - a lower axis, - connected to each other by at least two energy paths, at least one of which defines at least two gear ratios, the gear ratios differ from one path to another between the upper shaft and the axis lower, - in each energy path, the selective actuators establish each determined gear ratio and to deactivate in terms of power transmission at least one path other than the path that defines the aforementioned determined gear ratio, wherein: - the connection between the upper shaft and a respective input unit of each of the paths energy tories is permanent; and - the selective actuators are of a gradual type and / or capable of adapting the motor speed to the loading speed. Device according to claim 1, characterized in that the selective activators are wet multi-disc friction couplings. Device according to claim 1 or 2, characterized in that at least some of the selective activators are brakes that selectively connect a reaction member to a housing of the transmission device. Device according to any of claims 1 to 3, characterized in that each energy path is kinematically independent and comprises an output unit permanently connected to the lower shaft. Device according to any one of claims 1 to 4, characterized in that the two energy paths are approximately identical and are capable of being obtained between their input unit and their identical local gear ratios of the output unit, but are connected to the upper shaft and / or the lower shaft with a different transfer ratio. Device according to any one of claims 1 to 5, characterized in that each energy path is capable of a local direct drive gear ratio. Device according to any one of claims 1 to 6, characterized in that each selective activator can be placed in a neutral state, so that each gear ratio of an energy path is obtained by placing a single trigger in an activated state, while the energy path is placed in neutral when all selective activators of the energy path are in a neutral state. Device according to claims 1 to 7, characterized in that at least one energy path comprises the sub-paths, each corresponding to a respective local gear ratio, which is mechanically mounted in parallel between the input unit and the output unit. Device according to any one of claims 1 to 8, characterized in that at least one of the energy paths comprises at least one planetary gear train. Device according to any one of claims 1 to 8, characterized in that at least one of the energy paths comprises the first and second planetary gear trains, respectively comprises: the first and second planetary carriers, in which the planetary pinions they are mounted in pairs, in series, - the first and second solar gears, - the first and second ring gears, wherein: - the two ring gears are attached to the output unit, - the first planetary carrier and the second solar gear are attached to the input unit , and where the selective activators comprise: - a brake for the first solar gear, - a brake for the second planetary carrier, - a direct-acting clutch. Device according to any one of claims 1 to 8 or 10, characterized in that at least one of the energy paths comprises the first and second planetary gear trains, respectively comprising: - first and second planetary carriers, - first and second solar gears, - first and second ring gears, wherein: the first ring gear and the second planetary carrier are attached to the output unit, - the first planetary carrier and the second sun gear are attached to the input unit, and in where the selective activators comprise: a brake for the second ring gear, a brake for the first solar gear, a direct-acting clutch. Device according to any one of claims 1 to 11, characterized in that at least one of the input units and output units in each path is located at an intermediate position between the spatial ends of the path. Device according to any of claims 1 to 11, characterized in that the output unit and the input unit in each path are axially adjacent, in particular at a spatial end of the path. Device according to any one of claims 1 to 13, characterized in that it comprises controls capable of synchronizing the gradual placement of a selective activator in a neutral state with the gradual placement of another selective activator in an activated state.