WO2017221039A1

WO2017221039A1 - Automatic gearbox

Info

Publication number: WO2017221039A1
Application number: PCT/HR2017/000007
Authority: WO
Inventors: Mišo Georg RABATIĆ
Original assignee: Rabatić Mišo Georg
Priority date: 2016-06-21
Filing date: 2017-06-19
Publication date: 2017-12-28
Also published as: HRP20160716A2

Abstract

Automatic gear changer (gear box or transmission) with input torque control is comprised of driving (input) and driven (output) gearsets whereas all of the driving and driven gearsets are in a state of constant meshing; however, the torque or moment is transferred solely by the gear pair having driving or input gear firmly connected or integrated with cylinder (1) via pegs (11) residing on pegging axle (9) in accordance with a relative angle of rotation between the pegging axle (9) and cylinder (1) as well as relative angle of rotation between input (driving) shaft (12) and cylinder (1), and corresponding driven or output gear firmly connected or integrated to the output or driven shaft (17) via key (20). Relative rotational displacement angle of pegging axle (9) with respect to cylinder (1) facilitates rotation of pegs (11) from pegging axle (9) with respect to individual driving or input gears (7) and (5) and this in such a manner that an increase in the angle of rotation brings pegs (11) in an engagement with slots (6) and (8) of gears (5) and (7), respectively, so that the latter can sequentially exit the engagement and become free to rotate around cylinder (1), which in turn switches the location of torque transfer to the next still fully engaged gear. Set of driven or output gears (22) and (24) (with exception of gear (18) which is integrated with the driven or output shaft (17)) facilitates free, one-directional rotation of a driven shaft (17) within individual driven gear (22) and (24). This is realized through system of keys (20) and compression springs (21) located in slots (19) of driven or output shaft (17) in combination with spiral slots (23) and (25) on driven gears (22) and (24), respectively. This guarantees that in any given instant only one of driven gears remains firmly connected with the driven or output shaft thus transferring the automatic transmission torque.

Description

Automatic gearbox

DESCRIPTION OF THE INVENTION

Specific Area of invention application

This invention pertains to a gear or speed changer, which is intended for automatic ratio change (of rotational speeds) across the transmission depending on the change in input (driving) torque caused by the change in output torque (driven or load torque).

Technical problem

One of the main technical requirements during transmission of rotational movement (in accordance with the change in rotational speeds) from one mechanical subsystem to another, is the need for coordination of the ratio of required input and output torques (and corresponding power) throughout the wide range or transmission ratios.

State of the art

The above-mentioned technical problem or challenge is typically resolved through an appropriate system of gear or speed changers.

Gear or speed changers (transmissions) exist in a numerous implementations; among the ones used in transportation under direct human control there is an ever-increasing proportion of so-called automatic gear changers or automatic transmissions.

Although these present implementations fulfill the basic intent for freeing a driver of the activity of changing the gears, the present implementations are typically very complex and expensive or characterized by diminished efficiency and associated power losses [e.g., due to increased friction). As such they are difficult and impractical to apply in the case of smaller transportation vehicles or in transportation means that are directly powered by a human (for example, bicycles).

Presentation of the essence of invention

The foremost objective of present invention is to provide a change of transmission gear ratio in an automatic way (i.e., without the need for human intervention). This is achieved so that the change in transmission ratio is directly controlled through the quantity of input torque or moment in such a way that an increase in input torque results in a lower transmission ratio, which results in higher output torque for constant input torque or higher input rotational speed for constant output speed (or lower output speed for approximately constant input speed).

The automatic gear changer described in this patent application consists of a driving (input) and driven (output) gearset. Driving gearset is comprised of a drive shaft, which is inserted (through the relative rotational movement controlled by spring-based system] into the cylinder on top of which there is a set of gears of successively smaller diameter. The last gear, that is the one with the smallest diameter, is integrated i.e. firmly connected with the cylinder. By inserting a rotating pegging axle (connected with the input shaft through a separate gear mesh arrangement] between the sets of driving gears and cylinder, it is possible to create a different firm gearset combination, or completely free interconnection between each individual driving gear and the said cylinder. Depending on the degree of drive shaft rotation with respect to the cylinder, and corresponding rotation of the pegging axle with respect to said cylinder, firm connection (and torque transfer] can be realized between all driving gears and the above cylinder (this being the initial or starting configuration], or individual driving gears (in a successive order, from the largest toward the smallest, in accordance with an increase in rotational angle of the said pegging axle] can be made free of the firm connection and thus they will be bypassed in the torque transfer process.

Driven gearset is comprised of a driven shaft on which there is installed (through one- directional relative rotational displacement controlled by a system of keys and springs] a set of different driven gears with different, successively increasing diameters. The smallest driven gear is integrated with the driven shaft. All driven gears are always meshed with corresponding driving gears, so that, in accordance with this, for every driving gear that is (by means of pegging axle] in a firm connection with the cylinder there is corresponding driven gear securing the associated torque transfer. Due to the difference in rotational speeds of different driven gears positioned on the same shaft, and due to (through the related set of keys and springs] facilitated one-directional rotational motion of individual driven gears around the said shaft, only the gear with the highest rotational speed is (through the related set of keys and springs] firmly connected with the driven shaft and thus transferring the torque whereas all the remaining driven gears are either freely rotating around the driven shaft (in the case when their related driving gears are firmly connected with the cylinder) or are (almost) stationary (in the case when their related driving gears are not firmly connected with the cylinder).

In the extreme cases, at the highest gear (i.e., at the lowest input torque level) the first (largest) driving gear drives the first (i.e., smallest) driven gear, which is an integral part of the driven shaft, whereas in the lowest gear (i.e., at the highest input torque level) the last (smallest) driving gear, which is a part of the cylinder, drives the last (largest) driven gear.

Automatic gear changer (automatic gearbox or transmission), as described herein, realizes the needed change in transmission ratios solely by utilizing increase in input torque levels without any need for human intervention. Due to small number of basic mechanical components, this kind of automatic transmission is relatively simple and inexpensive, and at the same time very efficient, which is inherent to gearmesh-based implementations. Figure titles

Figure 1. - 3D representation of the gearset with visible driving and driven gears

Figure 2. - 3D representation of driving gearset

Figure 3. - 3D representation of disassembled driving gearset

Figure 4. - Longitudinal cross-section of driving gearset

Figure 5. - 3D representation of driven gearset

Figure 6. - 3D representation of disassembled driven gearset

Figure 7. - Longitudinal cross-section of driven gearset

Figure 8. - 3D representation of driving shaft and cylinder with springs

Figure 9. - 3D representation of driving shaft and cylinder with pegging axles

Figure 10. - Lateral cross-section of driving shaft and cylinder with springs

Figure 11. - 3D representation of gear-connection between driving shaft and pegging axles

Figure 12. - Lateral cross-section of driving shaft and pegging axles

Figure 13. - Lateral cross-section of first driving gear with pegging axles engaged

Figure 14. - Lateral cross-section of second driving gear with pegging axles engaged (3rd gear)

Figure 15. - Lateral cross-section of first driving gear with pegging axles disengaged

Figure 16. - Lateral cross-section of second driving gear with pegging axles engaged (2^nd gear)

Figure 17. - Lateral cross-section of first driving gear with pegging axles disengaged (2^nd gear)

Figure 18. - Lateral cross-section of second driving gear with pegging axles disengaged

Figure 19. - Lateral cross-section of second driven gear turning (keys compressed)

Figure 20. - Lateral cross-section of second driven gear engaged (keys in uppermost position)

Figure 21. - Automatic gearset schematic in initial (highest, i.e., 3^rd) gear

Figure 22. - Automatic gearset schematic in second gear

Figure 23. - Automatic gearset schematic in the last (lowest, i.e., 1^st) gear Detailed description of one implementation of present invention

In order to illustrate one possible implementation of present invention, in this application we present a simple, three-gear transmission setup the 3D representation of which is shown on Figure 1. The said transmission system is comprised of two sub-systems: driving (Figure 2] and driven (Figure 5} gearsets. From Figure 1 it can be seen that all driving gears are continuously meshed with all driven gears.

Driving gearset (disassembled 3D representation of which is shown in Figure 3] is comprised of driving shaft 12 with integrated ring 13 with inner gear 14 and supports 15 for springs 16.

On the said driving shaft 12 there is a cylinder 1 (as shown on Figures 8-10], which includes integrated supports 3 for springs 16, and the last (smallest] gear 2 in a row of gearsets. On the said cylinder 1 there are also inserted driving gears 5 and 7.

Between cylinder 1 and driving gears 5 and 7, at diametrically opposite sides of cylinder 1, in circular cavities 4 there are inserted two pegging axles 9 (shown in Figure 9].

The aforementioned pegging axles 9 are designed in such a manner that within the segments located in the areas of gears 5 and 7 there are created free volumes (shown on Figure 4] in order to form pegs (or wedges] 11, and at the edge of each pegging axle 9 there is an integrated gear 10, which is in a constant engagement with inner gear 14 of ring 13 located on the driving shaft 12 (shown on Figures 11 and 12].

At the other side, at the inner diameter (the one that is in contact with cylinder 1] of driving gears 5 and 7 there are created half-cylindrical slots 6 and 8 (shown in Figure 3], which facilitate rotation of pegging axle 9.

Pegging axles 9 through their rotation around their axes (within cavity 4 in cylinder 1, where the said rotation is caused by relative rotation of shaft 12 with respect to cylinder 1 due to compression of spring 16] can be positioned so that their pegs 11 engage (as in Figures 13, 14 and 16] or disengage (as in Figures 15,17 and 18] with/from the slots 6 and 8 on the driving gears.

In the case when pegs 11 of pegging axles 9 engage with the sides of slots 6 and 8 on the driving gears 5 and 7, those gears are in engagement with cylinder 1, and due to this they can transfer the input torque from shaft 12 to their corresponding driven gears 18 and 22, and thus to driven shaft 17.

In the case when pegs 11 of pegging axles 9 do not engage with the sides of slots 6 and 8 on the driving gears 5 and 7, those gears are not in engagement with cylinder 1, and due to this they do not transfer the input torque from driving shaft 12 to driven shaft 17; thus, they are free to turn around cylinder 1.

Implementation of driven gearset as shown on Figures 5-7 facilitates torque transfer from driving gears 2, 5 and 7 to driven shaft 17, and this is done in such a way that in a any given instant only one of the driven gears 18, 22 and 24 is in engagement with the driven shaft. This function is facilitated by an implementation of the driven shaft 17 in such a manner that within the shaft, in slots 19, at positions corresponding to driven gears 22 and 24 are inserted couples of keys 20 with compression springs 21; the latter - through their pre- compression - perform the function of moving the keys outward in a radial direction, perpendicular to the axis of driven shaft 17 (shown in Figures 19 and 20].

The aforementioned keys 20, due to a particular driven gear implementation with spiral slots 23 and 25 at the engagement diameter with driven shaft 17, facilitate one-directional turning of driven gears 22 and 24 around the driven shaft in instances when their rotational speed (due to their coupling with driving gears 2 and 5] is smaller than the rotational speed of shaft 17 (shown in Figures 19 and 21]. On the other hand, the said keys facilitate torque transfer to driven shaft (shown in Figure 20 as well as Figures 22 and 23] in instances when one of driven gears 22 or 24 is the gear facilitating torque transfer from that driving gear (2 or 5], which is in a firm coupling with cylinder 1 through the pegging axle 9.

Which of the driving gears 5 and 7 will be in a firm coupling with cylinder 1 and which one will be freely rotating depends on the rotational displacement of pegging axle 9 with respect to cylinder 1, and this is in turn determined by the amount of compression of springs 16 due to increasing torque or moment acting upon the input shaft 12 (shown on Figures 21-23].

From the afore-described relations it is visible that with an increase of input torque acting upon shaft 12 there is a sequential disengagement of driving gears 5 and 7 from cylinder 1, which in turn transfers the torque transmission function to driving gears with smaller diameter until at the end the process finishes with the smallest driving gear 2 that is integrated with cylinder 1).

The hereby described mechanism secures automatic change of transmission ratios (defined as ratios of gearbox output-to-input speeds] from the highest toward the smallest in accordance with an increase of input torque typically connected with an associated increase in output torque or load (e.g. , while climbing a hill].

Manner of usage of the present invention

Automatic gear changer or gearbox controlled by input torque, as described in this patent application, can be applied in all situations when it is desired to secure automatic change of transmission ratios (i.e., rotational speeds] due to an increase in input torque.

This type of gearbox is suitable for applications in situations dealing with lower power (torque] levels and in the areas of lower rotational speeds, and is especially suitable in applications for systems that are propelled under direct human power (e.g., bicycles].

The hereby-described basic functionality characterizing this type of gearbox can be applied to an arbitrary number of pairs of driving and driven gears (facilitating larger number of transmission ratios]. In addition, certain functionalities can be achieved through some other ways utilizing some other technical solutions while maintaining the basic, previously described functional principles. Nomenclature used in figures and text

1 - Cylinder

2 - Smallest driving gear, integrated with cylinder

3 - Spring support on cylinder

4 - Slots for positioning of pegging axles in cylinder

5 - Middle driving gear on cylinder

6 - Slot for engaging pegging axle with middle driving gear

7 - First (largest] driving gear on cylinder

8 - Slot for engaging pegging axle with first driving gear

9 - Pegging axle

10 -Gear integrated with pegging axle

11 -Pegs on pegging axle

12 -Driving shaft

13 -Ring integrated with driving shaft

14 -Inner gear at the ring of driving shaft

15 -Spring supports at the ring of driving shaft

16 -Compression springs

17 -Driven shaft

18 - Smallest driven gear, integrated with driving shaft

19 -Slots on driven shaft used for insertion of keys and springs

20 -Keys for one-directional rotational connection between driven gears and driven shaft

21 -Compression springs associated with driven keys

22 -Middle driven gear

23 -Spiral slot at engagement diameter of middle driven gear

24 -First (largest) driven gear

25 - Spiral slot at engagement diameter of first driven gear

Claims

Patent claims

1. Automatic gear changer (gearbox with controlling input torque, comprised of driving and driven gearsets with driving gearset being comprised of driving shaft (12] with integrated inner gearing (14) and spring supports (15); cylinder (1) with integrated smallest driving gear (2), spring supports (3) and cavities (4) for pegging axle; two pegging axles (9) with specially formed pegs (11) and integrated gearing (10); driving gearset (5) and (7) with slots (6) and (8) and with sets of compression springs (16) placed between driving shaft (12) and cylinder (1); and, driven gearset comprised of driven shaft (17) with an integrated smallest driven gear (18), and slots (19) for placement of keys (20) and compression springs (21) along with a driven gearset (22) and (24) with appropriately formed spiral slots (25),

characterized by the fact that while all driving and driven gearsets remain in constant engagement (i.e., are always meshed) the transmission torque (or power) is transmitted solely by that particular gearset for which the driving gear is firmly connected or integrated with cylinder (1) through pegging axle (9), and the corresponding driven gear is firmly connected or integrated with driven shaft (17) through key (20).

2. Automatic gear changer according to claim 1. characterized by the fact that driving shaft (12), cylinder (1) and pegging axles (9) of driving gearset are simultaneously engaged by means of spring set (16) positioned between drive shaft (12) and cylinder (1), and by means of gearmesh between gear (10) of pegging axle (9) and inner gearing (14) at ring (13) of driving shaft (12).

3. Automatic gear changer according to claim 2. characterized by the fact that an increase in input torque acting upon shaft (12), due to its connection with spring set (16), facilitates relative rotational displacement between driving shaft (12) and cylinder (1), and, at the same time, due to gearmesh-type connection of inner gearing (14) on ring (13) of driving shaft (12) and gear (10) of pegging axle (9), it also facilitates relative rotational displacement of pegging axle (9) with respect to cylinder (1).

4. Automatic gear changer according to claim 1. and 3. characterized by the fact that relative rotational displacement of pegging axle (9) with respect to cylinder (1) facilitates turning of pegs (11) of pegging axle (9) with respect to driving gears (5) and (7), and this in such a manner that with an increase in the angle of turning the pegs (11) engage with slots (6) and (8) of gears (5) and (7) in such a way that they sequentially exit from engagement and become free to rotate around cylinder (1), which leads to change in torque transfer location to the next gear that is still in engagement.

5. Automatic gear changer according to claim 1. characterized by the fact that to the set of driven gears (22) and (24) (with exception of gear (18) which is integrated on driven shaft (17)), through a system of keys (20) and compression springs (21) located in slots (19) of driven shaft (17), and due to spiral slots (23) and (25) on the aforementioned driven gears, it has been made possible one-directional free rotation of driven shaft (17) within individual driven gears (22) and (24), which secures that in any given instant only one of driven gears remains firmly connected with the driven shaft thus transmitting the gearbox torque.