SK280408B6 - Transmission device - Google Patents

Abstract

A transmission device contains two transmission modules (180b, 180c), which are arranged in a row and upon different axes (Db, Dc), and means for changing transmission ratio for selective engaging each of two modules (180b, 180c) in one or second out of at least two transmission ratios. Mechanical connecting means (2b, 1c) couple an input of the first module (180c) with an output of the second module (180b), whilst said modules (180b, 180c) are operatively arranged in a row. Means for changing the transmission ratio are represented by control means (29, 31, 137, 158) disposed in the modules (180b, 180c). In at least one of the modules (180b, 180c) there are control means sensitive to at least one function parameter that is read in the module (180b, 180c) itself.

Description

Technical field

The invention relates to a transmission device comprising at least two transmission modules arranged in series on different axes, control means for controlling the function of each of the two modules selectively in one and the other of at least two transmission ratios.

BACKGROUND OF THE INVENTION

In modern motor vehicles, the drive and transmission unit must be as compact as possible. However, this often creates problems, especially in the case of front-wheel-drive vehicles, more specifically when the engine consists of more than four cylinders and if the transmission device has many gear ratios and / or is of the automatic shifting type, since then it is necessary transmission device cumbersome and bulky.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to overcome these disadvantages, more precisely to provide a multi-gear transmission device which is well positioned in a space having a shape which is a priori difficult to use.

SUMMARY OF THE INVENTION

This object is achieved by a transmission device comprising at least two transmission modules arranged in series on different axes, and means for controlling the function of each of the two modules selectively in one and the other of the at least two transmission ratios according to the invention. of the modules, connecting mechanical means to the output of the second module, the modules being functionally in series, and that the control means responsive to at least one function parameter sensed in the module itself are disposed within the modules.

The transmission device according to the invention thus consists of at least two transmission sub-assemblies mechanically connected in a row and control means for controlling each of the two sub-assemblies selectively in one or the other of at least two transmission ratios, both sub-assemblies being different axis modules connected to each other by mechanical coupling means. .

The solution according to the invention thus allows the installation of relatively small modules in a row in an arrangement that is freely selectable to optimally utilize the available engine compartment of the vehicle.

The solution according to the invention also makes it possible to carry out structures in which the output of the transmission device is in a preferred position for transmission on each of the drive wheels of the vehicle.

Thus, the control means responsive to at least one function parameter sensed in the module itself are disposed in the modules, allowing substantially independent shifting between one and the other gear ratio in at least one of the modules.

Thus, irrespective of the arrangement of the modules, there is no need to provide a complicated control device which has to be adapted to the modules. This further reduces manufacturing costs that are specific to each type of vehicle to be equipped with the modular transmission device of the invention.

This substantially independent control of at least some of the modules does not preclude the modules from receiving simple information from the outside, such as information that can be transmitted electrically, for example to control the downshift of the module in its greatest speed reduction mode when the vehicle driver presses the accelerator pedal.

According to a preferred embodiment of the invention, the two modules have parallel axes of rotation.

The transmission device according to the invention preferably comprises at least one add-on module, wherein the two transmission modules and the at least one add-on module together form a functional sequence of at least three modules which are connected mechanically in series by mechanical coupling means interposed between the modules.

According to a further preferred embodiment of the invention, at least three modules are arranged side by side along parallel axes. According to another preferred embodiment of the invention at least three modules form a straight line.

According to another preferred embodiment of the invention, at least three modules form an arc row.

According to another preferred embodiment of the invention, the add-on module is coaxially connected to one of the two transmission modules.

According to a further preferred embodiment of the invention, at least one of the modules comprises a differential transmission mechanism with three rotating elements provided with interlocking short teeth, a freewheel arranged between one rotating element and the module housing, the means for changing the transmission ratio being , means for pushing the clutch to engage it and means for releasing the friction clutch movable axially in one of the three rotatable elements.

According to a further preferred embodiment of the invention, the means for pushing the clutch comprises centrifugal weights.

The means for pushing the clutch preferably comprise resilient means.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which: FIG. 1 shows an axial section through a transmission device according to the invention, with the two end modules shown only in half, FIG. 2 and 3 show a diagram of two examples of a drive and transmission unit according to the invention for a front-wheel drive vehicle, and FIG. 4 is a perspective view schematically of another example of a transmission device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the embodiment shown in FIG. 1, there is only a partial and schematic representation of a motor 183 which drives an output shaft via a clutch 184, for example of the automatic type. The clutch 184 shows its outer cover. The output shaft is at the same time the input shaft 1 of the first two-ratio module 180a, whose output 2a is coaxial with the input formed by the input shaft 1, and lies on the opposite side. The output 2a is formed by a gear that engages an input 1b formed by an input gear wheel in a second dual gear module 180b that is identical to the first module 180a except for the differences which will be explained in more detail below. The output 2b of the second module 180b engages the input 1c of the third module 180c having an output 2 forming an output from the transmission device consisting of the modules 180a, 180b, 180c.

According to the invention, these modules 180a, 180b, 180c may have respective axes Da, Db, Dc that differ from each other instead of the coaxial arrangement. For example, these axes Da, Db, Dc may be parallel to one another and the axial length of the transmission device is then almost equal to the axial length of any of the three modules 180a, 180b, 180c.

Each module 180a, 180b, 180c consists of a housing 9 in which a combination of gears is formed, forming different transmission ratios between the input 1, 1b or 1c and the output 2a, 2b or 2.

In the example shown in FIG. 1, the combination of gears, see second module 180b, consists of a planetary gear, also called an epicycloid gear. The inner sun gear 3 is rigidly connected to the input 1b formed by the input shaft, so that it is driven by the input shaft. The inner sun gear 3c is engaged with the planet wheels 4 mounted freely rotatable on the carrier 5. The carrier 5 is rigidly connected to the central shaft 6 connected to the outlet 2b and having the same pivot axis Db as the input 1b. For example, a planetary gear may have three planet wheels 4 (of which only one module 180b is shown in FIG. 1), which are rotatably supported on three axes E spaced about the axis of rotation Db.

In addition, the teeth of the planet wheels 4 are engaged with the internal teeth of the outer central or crown wheel 7, the center of which is also in the axis of rotation Db about which it rotates.

As is well known, the transmission ratio between the inlet 1b and the outlet 2b depends on the mechanical connections between the rotating elements (inner sun gear 3, carrier 5 and ring gear 7) of the planetary gear. In the example shown, these mechanical connections are selectively made between the carrier 5 and the ring gear 7. The freewheel 8 provided between the stationary housing 9 and the outer edge of the ring gear 7 prevents rotation of the ring gear 7 in the opposite direction against the inlet 1b.

A coupling with a plurality of disks 14, 15 is provided between the ring gear 7 and the carrier 5 to ensure selective coupling of the two rotary elements. This coupling consists of a bundle of axially sliding disks 14, 15.

The first bundle disks 14 are coupled to rotate together with the ring gear 7. To this end, the first disks 14 are provided on the outer edge with external teeth 18 which extend into the inner grooves 19 of the ring gear 7, which are parallel to the axis Db. The internal grooves 19 are formed between the finger projections 20 belonging to the ring gear 7.

The second bundle disks 15, each located between the two first disks 14, are connected to rotate together with the carrier 5. For this purpose, the second disks 15 are provided at their inner edge with inner teeth 21 which extend into the outer grooves 22 which are parallel to the axis Db and associated with the carrier 5. The outer grooves 22 allow axial movement of the second disks 15 against the carrier 5.

The stack of disks 14, 15 can be selectively clamped by a mechanism mounted on the central shaft 6.

This mechanism consists of a disk thrust element 17, compression springs 29 (of which only one is shown), disposed around a central shaft 6, a centrifugal weight 31 and a carrier 30 of these weights 31. The carrier 30 is fixedly connected to the central shaft 6, while the disc pressure element 17 is axially displaceable between the carrier 30 and the disk bundle 14, 15 and is connected to the central shaft 6 to be rotated together, being axially slidable thereon.

The peripheral surface of the disc pressing element 17 is in contact with the first or second disc 14, 15 (e.g., the second disc 15) forming one end of the bundle, while the other disc 14 or 15 forming the second end of the bundle is in contact with the carrier 5. Thus, when the disk thrust element 17 is pressed axially with sufficient thrust to the carrier 5, the bundle of disks 14, 15 is pressed together and the ring gear 7 and the carrier 5 are joined together. Compression springs 29 are provided between the carrier 5 and the disk thrust element 17. The pressure exerted by the compression springs 29 causes the disk thrust element 17 to be pushed away from the carrier 5 and hence to release the bundle of disks 14,15.

Each weight 31 is provided with a protrusion 33 which forms an axially displaceable component which engages the disc pressure element 17. The protrusion 33 acts as a cam determining the distance between the disc pressure element 17 and the carrier 30 which is axially stationary against the carrier 5. The weights 31 are When the pressure of the compression springs 29 is overcome, the disc pressure element 17 exerts a down pressure which is a monotonically increasing function of the speed of rotation of the output 2.

If the rotational speed of the carrier 5 and its central shaft 6 is low or even equal to zero, the weights 31 are in the rest position shown at the bottom of the second module 80b, at the bottom of the respective notch 32. This is due to the action of compression springs 29 that push the disc pressure element 17. As the rotational speed of the carrier 5 increases, the weight 31 exits its rest position by centrifugal force. The protrusions 33 of the weight 31 are retained by a protrusion 36 on the periphery of the disc pressing element 17, the weight 31 being pivoted as shown in the upper portion of the second module 180b. As a result of this pivotal movement, the protrusions 33, the portion engaging the disk thrust element 17 is an axially displaceable component, axially spaced the disk thrust element 17 away from the carrier 30. Because the carrier 30 is firmly attached to the central shaft 6, the disk thrust element 17 is pressed against of the carrier 5 against the action of the compression springs 29.

Thus, after exceeding the predetermined rotational speed of the carrier 5, the centrifugal force lifts the weight 31 as shown in the upper part of the second module 180b, these weights 31 pushing the disk pressure element 17 against the bundle of disks 14, 15 against the action of the compression springs 29.

Further, an axial bearing 137 is provided between the ring gear 7 and the disk thrust element 17.

In addition, the teeth of the inner sun gear 3, the planet wheels 4 and the crown wheel 7 are of the helical or helical type. This is a classic measure to eliminate noise when engaging the gear. However, it is known that oblique teeth in operation generate an axial thrust applied to the parts provided with these teeth. As a result, while decreasing the rotational frequency, the ring gear 7 creates an axial force FAC which is transmitted to the disc thrust element 17 by the thrust bearing 137 and which is proportional to the torque on the input shaft 1.

The bevel direction is selected such that the contact force FAC is added to the contact pressure of the compression springs 29.

The difference between the axial thrust exerted by the weights 31 on the disk thrust element 17 and the opposite force acting on the same disk thrust element 17 by the compression springs 29 together with the axial force FAC creates, if this difference is positive, a clamping force acting on the disk bundle 14, 15.

Depending on the torque to which the inlet 1b is subjected, the clamping force will be sufficiently high or not to attach the carrier 5 to the ring gear 7 of the epicycloid or planetary gear. If the torque applied to the input 1b is relatively small compared to the rotational frequency of the output 2b, the clamping force will be sufficiently high and the carrier 5 is firmly attached to the ring gear 7. In this situation, the planet wheels 4 cannot roll over the ring gear 7 and As a result, even the planet wheels 4 cannot roll on the inner sun gear 3. This creates a connection for co-rotating the inlet 1b with the carrier 5 and thus a direct drive connection between the inlet 1b and the outlet 2b of the second and module 180b.

In contrast, if the torque applied to the input 1b is relatively high compared to the rotation speed of the carrier 5, the clamping force applied to the bundle of disks 14, 15 is not high enough to attach the ring gear 7 to the carrier 5. In this case, the carrier 5 tends to remain stationary under the load and is driven by the outlet 2b so that the planet wheels 4 act as a reversing device, that is, they rotate the ring gear 7 in the opposite direction to the rotation direction of the inlet 1b. However, this is prevented by the freewheel 8, so that the ring gear 7 remains stationary against the housing 9 and the carrier 5 rotates at a rotational frequency of magnitude jc between the rotational frequency of the input 1b and the rotational frequency of the rotary gear 7 equal to zero. In this case, the second module 180b functions as a speed reducing transmission.

Between these two situations, there is an intermediate situation in which the torque applied to the input 1b is of a medium magnitude compared to the carrier rotation speed 5. This corresponds to a predetermined range of torque sizes of the input 1b at each given carrier rotation frequency 5 and the carrier rotation range 5 at each input torque amount 1b. In this situation, the clutch with the disks 14, 15 tends to remain in any pre-condition, i.e. to remain in engagement when in engagement state, and to remain in a switch state when in a switch state.

More specifically, when the clutch is engaged, no force is transmitted between the teeth of the planetary gears 4 and the ring gear 7 and as a result the axial force FAC disappears. In other words, once the upshift occurs, the subsequent downshift of the module will require a significant reduction in the rotational speed or a substantial increase in the torque applied to the input 1b. Once the module has been shifted down, the axial force of the FAC reappears and as a result stabilizes the operation of the state to reduce the rotational speed.

In other words, each time the clutch operating state changes, the axial force FAC changes in the direction of stabilization of the currently engaged gear ratio.

The two modules 180b, 180c can be exactly identical, even in terms of their functional application. However, in the example shown, the first module 180a differs from the two modules 180b, 180c in that the number of weights 31 in the first module 180a is much smaller, for example three or four weights 31 instead of thirty or forty. Among the weights 31 of the first module 180a are compression springs 158 which axially push the disc pressure element 17 in the clutch engagement direction, in other words, in the same direction as the weights 31 when they are subjected to centrifugal force.

Conversely, the action of the compression springs 29 which tend to disengage the coupling is suppressed.

The operation is as follows: first the clutch discs 14, 15 of the first module 180a are compressed by the compression springs 158 and the discs 14, 15 of the modules 180b and 180c are disengaged by the compression springs 29 so that the first module 180a operates in direct drive and the modules 180b and 180c work transfers. Of the two modules 180b and 180c, in the second module 180b, the rotational speed is higher and the transmitted torque is less. Therefore, in this second module 180b, a state is first achieved in which its weights 31 can disengage the clutch disks 14, 15 under the influence of centrifugal force, so that the second module 180b performs a shift upwards for direct drive. This reduces the torque transmitted to the other, i.e., the third module 180c, but not its rotational frequency, which is determined by the rotational frequency of output 2. This rotational frequency must therefore be increased so that, assuming a constant torque of the weights 31 of the third module 180c transferring it to a direct drive such that the transmission device will operate at a third transmission ratio which is the direct drive ratio of the entire transmission device comprised of the modules 180a, 180b, 180c.

When the input or first module 180a, due to the presence of torque on the input shaft 1, operates as a reduction gear, the remaining modules 180b, 180c continue to operate as described, with three exceptions:

- since the torque at input 1b is increased, shifting from the first gear to the second gear requires greater centrifugal force acting on the weight portion 31 of the second module 180b and will therefore be performed at a higher engine speed:

- for the same reason, shifting from the second gear to the third gear will require a greater centrifugal force acting on the weight portion 31 of the third module 180c and as a consequence the output 2 will be rotated at a higher frequency:

- as soon as shifting from second to third gear is performed, the engine rotational speed will increase; as long as the drive torque does not drop sufficiently (at a motor rotation frequency that corresponds to the maximum torque value, the torque decreases as a function of the motor rotation speed) so that the compression springs 158 cause the input or first direct drive module 180a to shift. then forms the fourth gear ratio.

In this way, an automatic car transmission has been created that operates with either three gear ratios and a relatively low engine speed for normal driving or sports driving with four ratios, the first three of which differ from the first two for normal driving and cause that the engine is operating at a rotational speed near maximum power, which optimizes its operation.

The function of the weight 31 of the first module 180a, when the engine speed is increased, is to increase the torque threshold at which the first module 180a shifts from a direct drive to a reduction operation. This prevents the first module 180a from shifting to a reduction operation when the motor rotation speed is already relatively high.

Since the transmission device consists of modules with a certain arrangement, this transmission device is efficient, simple and, in particular, its axial dimension is small. For example, the illustrated arrangement may be advantageous in a drive and transmission unit adapted for a front-wheel drive vehicle with a longitudinally mounted engine, before or after the drive axle.

This type of transmission device can also be used in an engine with substantially horizontal cylinders positioned in the same plane as the axis of rotation of the modules Da, Db and Dc.

Since the modules 180a, 180b, 180c include actuating means (weights 31, compression springs 158, compression springs 29, thrust bearing 137), there is no need to provide any control device that is adaptable to the array of these modules 180a, 180b, 180c. In essence, there is only a need to provide several identical or similar modules 180a, 180b, 180c and to connect them to each other, for example by connecting their housing 9.

In FIG. 2 shows another example of a drive and transmission unit according to the invention.

The engine 183 is disposed across, in other words, parallel to the axle with the drive wheels 213, each of which is connected to one of the outputs of the differential 211. The differential 211 may be in principle of the conventional type. The differential input 211 is connected to the output 2 of the transmission device.

The transmission device consists of four modules 180a, 180b, 180c and 180d instead of three as in the previous example. The first three modules 180a, 180b, 180c are identical to the same described modules of FIG. 1 and the fourth module 180d is identical to the second and third modules 180b, 180c.

Modules 180a and 180b are coaxial to each other and coaxial to motor 183. In other words, the output 2a of the first module 180a is the same as the input 1b of the second module 180b.

Similarly, the third and fourth modules 180c and 180d are coaxial such that the output 2c of the third module 180c is the same as the input 1d of the fourth module 180d. The common axis of the first and second modules 180a and 180b is parallel to and spaced from the common axis of the third and fourth modules 180c and 180d. The output 2b of the second module 180b is formed by a gearwheel engaging another gearwheel constituting the inlet 1c of the third module 180c.

With this arrangement, the engine 183, the clutch 184 and the transmission device may be more easily disposed between the drive wheels 213, further providing the advantage that the differential 211 may be located equidistant from the two drive wheels 213.

The exemplary embodiment shown in FIG. 3. it may be advantageous if the motor 183 is longer in the axial direction, for example, when the motor 183 has six cylinders in a row.

There is also provided a transmission device consisting of four modules 180a, 180b, 180c and 180d. whose output is also an input to the differential 211.

The arrangement of the first and second modules 180a, 180b against the third and fourth modules 180c and 180d is the same as in the embodiment of FIG. First

The output 2b of the first module 180b is formed by a gear that engages the gear forming the inlet 1c of the third module 180c. The third module 180c and the second module 180b are arranged on one side of the plane of the gears constituting the inlet 1c and the outlet 2b. The overall arrangement of the third and fourth modules 180c and 180d and the differential 211 is identical to that of FIG. Second

In the embodiment of FIG. 4, the four modules 180a, 180b, 180c and 180d are arranged similarly to the example of FIG. 1, the three modules 180a, 180b, 180c, but the rotational axes Da, Db, Dc, and Dd, instead of being coplanar, are arranged in a circle, i.e. they represent four forming lines of the same thought cylinder. The first and second modules 180a, 180b are connected to the third and fourth modules 180c and 180d in the same way as in the embodiment of FIG. 1 and 3.

The second and third modules 180b, 180c are connected to the remaining modules 180a and 180d, as in the embodiment of FIG. 1, but this cannot be seen in FIG. 4 with respect to a perspective representation. The third and fourth modules 180c and 180d are connected to each other by a gear formed by the intermediate gear 131, wherein the gears forming the input 1d of the fourth module 180d and the output 2c of the third module 180c may have a smaller diameter so as not to interfere with the gears constituting the output 2a of the first module. 180a and the input 1b of the second module 180b.

Of course, the invention is not limited to the described and illustrated embodiments.

All modules 180a, 180b, 180c and 180d may be identical, including the input first module 180a, thereby creating an automatic transmission permanently in operation with, for example, four transmission ratios (three modules) or five transmission ratios (four modules).

Although it is advantageous that the operation of the individual modules is as independent as possible, it is of course possible to provide means for supplying specific information to the modules, i.e. to control them under predetermined conditions, for example in the event of acceleration or braking disruptions.

Neither the manner in which the modules are coupled to each other, the manner in which the transmission device is attached to the vehicle frame, nor the eventual cover that can be adapted to protect the gears are shown. These additional means can be readily prepared by any person skilled in the art. The modules may be arranged in such a way that their axes form certain angles together.

Claims (10)

PATENT CLAIMS A transmission device comprising two transmission modules (180b, 180c) arranged in series on different axes (Db, Dc), and means (14, 15, 29, 31, 137, 158) for changing the transmission ratio to selectively indicate each of both modules in one and the other of at least two transmission ratios, characterized in that the input of one module (180c) connects to the output of the other module (180b) mechanical coupling means (2b, 1c), the modules (180b, 180c) being functionally arranged and in that the means for changing the gear ratio are formed by control means (29, 31, 137, 158) which are distributed in the modules (180b, 180c), wherein in at least one of the modules (180b, 180c) the control means are sensitive at least one function parameter read in module (180b, 180c) itself. The transmission device according to claim 1, characterized in that both modules (180b, 180c) have parallel axes of rotation (Db, Dc). A transmission device according to claim 1 or 2, characterized in that it comprises at least one add-on module (180a, 180d), wherein two transmission modules (18ob, 180c) and at least one add-on module (180a, 180d) together. forming a functional sequence of at least three modules (180a, 180b, 180c, 180d) which are mechanically connected in series by mechanical coupling means (2a, 1b, 2b, 1c, 2c, 181, Id) which are interposed between the modules (180a, 180b) , 180c, 180d>. The transmission device according to claim 3, characterized in that at least three modules (180a, 180b, 180c, 180d) are arranged side by side along parallel axes (Da, Db, Dc). The transmission device according to claim 4, characterized in that at least three modules (180a, 180b, 180c) form a straight line. The transmission device of claim 4, wherein at least three modules (180a, 180b, 180c, 180d) form an arc row. A transmission device according to claim 3, characterized in that the additional module (180a, 180d) is coaxially connected to one of the two transmission modules (180b, 180c). The transmission device according to any one of claims 1 to 7, characterized in that at least one of the modules (180a, 180b, 180c, 180d) comprises a differential transmission mechanism with three rotating elements (3, 5, 7) provided with interlocking engagement. a freewheel (8) arranged between one rotary element (7) and a module housing (180a, 180b, 180c, 180d), the means for changing the transmission ratio being formed by a friction clutch (14, 15) arranged between the two rotary elements (7). 5, 7), means (31, 158) for pushing the clutch to engage it and means for releasing the friction clutch (14, 15) movable axially in one of the three rotatable elements (3, 5, 7). The transmission device according to claim 8, characterized in that the coupling pressing means consist of centrifugal weights (31). The transmission device according to claim 8 or 9, characterized in that the means for pushing the clutch comprise resilient means (158). 2 drawings