DUAL MASS DOG COLLAR AND/OR DUAL MASS DOG HUB FOR A POWER TRANSMISSION SYSTEM

Abstract

The present application relates to a dual mass dog collar 1 of a dog clutch, to a dual mass dog hub 3 of a dog clutch, to a power transmission system (gearbox) 2 and to a method to operate said power transmission system, comprising at least one dual mass dog collar 1 and/or at least one dual mass dog hub 3.

Claims

1. A dual mass dog collar (1), of a dog clutch wherein the dual mass dog collar (1) comprises an inner part (40) being torque proof engaged with an assigned dog hub or with an assigned shaft, comprising engagement means (41) on the inner circumferential surface and an outer part (50) comprising on at least one of its surfaces engagement means (60), adapted for torque transmission to/from an engageable free gear wheel, wherein the inner part (40) and the outer part (50) have a common rotational axis, wherein the inner part (40) is at least partially arranged within the outer part (50), wherein the inner part (40) and the outer part (50) are arranged concentrically to the assigned shaft, wherein the inner part (40) is arranged angularly deflectable with respect to the outer part (50) around the common rotational axis, wherein the inner part (40) is coupled to the outer part (50) by means of a first elastic element (70) and a second elastic element (80) wherein the elastic elements (70, 80) are positioned in a parallel configuration, wherein Each one of the elastic elements (70, 80) are received within at least one compartment formed by the inner part (40) and the outer part (so), and wherein the dual mass dog collar (1) is configured axially movable along the assigned dog hub or shaft guided by the provided engagement means (201) of the assigned shaft due to the interaction of the engagement means (201) of the assigned shaft with the corresponding engagement means (41) of the inner part (40).

2. A dual mass dog collar (1) of a dog clutch, according to claim 1, wherein the spring constant of the first elastic element (70) is lower than the spring constant of the second elastic element (80).

3. A dual mass dog collar (1) of a dog clutch, according to any of claims 1 to 2, wherein the elastic elements (70, 80) are adapted in a way that the first elastic element (70) is initially deformed upon the angular deflection of inner/outer part and the second elastic element (80) begins to deform after the progression of the deflection of inner/outer part accompanied by a simultaneous and continuing deformation of the first elastic element (70), and wherein the inner part (40) and the outer part (50) are adapted to rotate with the same angular velocity if the two elastic elements (70, 80) are fully loaded under the occurring load.

4. A dual mass dog collar (1) of a dog clutch, according to any of claims 1 to 3, wherein the inner and/or the outer parts comprise elastic element supports with dumping elements.

5. A dual mass dog collar (1) of a dog clutch, according to any of claims 1 to 4, wherein the first and the second elastic elements (70, 80) are spring elements, or wherein the first elastic element (70) is provided as a spring element and the second elastic element (80) is provided as a rubber element.

6. A dual mass dog collar (1) of a dog clutch, according to any of claims 1 to 5, wherein the inner part (40) is coupled to the outer part (50) by means of additional elastic elements.

7. A dual mass dog hub (3) of a dog clutch, wherein the dual mass dog hub comprises an inner part (340) comprising engagement means (341) on the inner circumferential surface and being torque proof engaged with an assigned shaft, and an outer part (350) comprising engagement means (360), adapted for torque transmission to/from at least one dog collar, wherein the inner part (340) and the outer part (350) have a common rotational axis, wherein the inner part (340) is at least partially arranged within the outer part (350), wherein the inner part (340) and the outer part (350) are arranged concentrically to the assigned shaft, wherein the inner part (340) is arranged angularly deflectable with respect to the outer part (350) around the common rotational axis, wherein the inner part (340) is coupled to the outer part (350) by means of a first elastic element (370) and a second elastic element (380) wherein the elastic elements (370, 380) are positioned in a parallel configuration, wherein Each one of the elastic elements (370, 380) are received within at least one compartment formed by the inner part (340) and the outer part (350) and wherein the at least one dog collar is configured axially movable along the assigned dual mass dog hub or shaft guided by the provided engagement means (360) of the outer part (350) due to the interaction of the engagement means (360) of the outer part (350) with the corresponding engagement means of the at least one dog collar.

8. A dual mass dog hub (3), according to claim 7, wherein the spring constant of the first elastic element (370) is lower than the spring constant of the second elastic element (380).

9. A dual mass dog hub (3), according to any of claims 7 to 8, wherein the elastic elements (370, 380) are adapted in a way that the first elastic element (370) is initially deformed upon deflection of inner/outer part and the second elastic element (380) begins to deform after the progression of the deflection of inner/outer part accompanied by a simultaneous and continuing deformation of the first elastic element (370), and wherein the inner part (340) and the outer part (350) are adapted to rotate with the same angular velocity if the two elastic elements (370, 380) are fully loaded under the occurring load.

10. A dual mass dog hub (3), according to any of claims 7 to 9, wherein the inner and/or the outer parts comprise elastic element supports with dumping elements.

11. A dual mass dog hub (3), according to any of claims 7 to 10, wherein the first and the second elastic elements (370, 380) are spring elements, or wherein the first elastic element (370) is provided as a spring element and the second elastic element (380) is provided as a rubber element.

12. A dual mass dog hub (3), according to any of claims 7 to 11, wherein the inner part (340) is coupled to the outer part (350) by means of additional elastic elements.

13. A gearbox (2), comprising: an input shaft (10), supporting input gear wheels (110, 120); an output shaft (20), supporting output gear wheels (210, 220) and at least one dog clutch comprising at least one dual mass dog collar (1) according to any of claims 1 to 6 and/or at least one dual mass dog hub (3) according to any of claims 7 to 12, wherein each of the input gear wheels (110, 120) meshes with at least one corresponding output gear wheel (210, 220), thereby defining a gear ratio, and wherein at least one of the input gear wheels (110, 120) or at least one of the output gear wheels (210, 220) of a gear ratio is an engageable free gear wheel, and may be engaged to the assigned shaft by the assigned at least one dual mass dog collar (1) according to any of claims 1 to 6 and/or the at least one dog collar of the at least one dual mass dog hub (3) according to any of claims 7 to 12.

14. A gearbox (2) according to claim 13, wherein the input gear wheel (110), is a bevel pinion and the output gear wheels (210, 220) are bevel gears and wherein the input shaft (10) and the output shaft (20) form a 90° angle.

15. A gearbox (2), according to any of claims 13 to 14, wherein the axial movement of the at least one dual mass dog collar (1) along the assigned shaft (10, 20), or the axial movement of the at least one dog collar of the at least one dual mass dog hub (3) along the assigned at least one dual mass dog hub (3), is guided by helical engagement means (201, 360) so that the dual mass dog collar (1) is rotated relative to assigned shaft (10, 20) upon the axial movement of the dual mass dog collar (1), or the at least one dog collar of the at least one dual mass dog hub (3) is rotated relative to assigned shaft (10, 20) upon the axial movement of the at least one dog collar of the at least one dual mass dog hub (3).

16. The gearbox (2) according to any of claims 13 to 15, further comprising a control unit, position sensors and measuring instruments taking according measurements and providing them to the control unit, wherein the control unit is adapted to command a gear ratio changing action with the provision of respective commands to the at least one dual mass dog collar (1) and/or to the at least one dog collar of the dual mass dog hub (3) after assessing and processing the provided data.

17. A method for operating a gearbox (2) according to any of claims 13 to 16, comprising the following steps: rotating the input shaft (10) and transferring power to the output shaft (20) by means of an initial gear ratio; commanding a gear ratio changing action with the provision of respective commands to the at least one dual mass dog collar (1) and/or to the at least one dog collar of the at least one dual mass dog hub (3) after assessing and processing data in a control unit, from the initial gear ratio to a consecutive gear ratio; axially moving a second dual mass dog collar (1) according to any of claims 1 to 6 and/or a second dog collar of the dual mass dog clutch (3) according to any of claims 7 to 12, towards the engageable free gear wheel of the consecutive gear ratio and thereby engaging the engageable free gear wheel of the consecutive gear ratio, torque proof fixing said gear wheel with the assigned shaft, axially moving the at least one first dual mass dog collar (1) according to any of claims 1 to 6 and/or the at least one first dog collar of the at least one dual mass dog hub (3) according to any of claims 7 to 12 and thereby disengaging the at least one first dual mass dog collar (1) according to any of claims 1 to 6 or the at least one first dog collar of the at least one dual mass dog hub (3) according to any of claims 7 to 12 from the engageable free gear wheel of the initial gear ratio, rotating the input shaft and continuously transferring power to the output shaft during the gear changing action, until the entire power is transferred by means of a new gear ratio.

18. The method according to any of claims 13 to 16, wherein the form of the engagement means (201, 360) forces the at least one dual mass dog collar (1) according to any of claims 1 to 6 and/or the at least one dog collar of the at least one dual mass dog clutch (3) according to any of claims 7 to 12 to rotate, when moved axially.

19. An automotive vehicle or a boat comprising at least one dual mass dog collar (1) according to any of claims 1 to 6 and/or at least one dual mass dog clutch (3) according to any of claims 7 to 12 or a gearbox (2) according to any of claims 13 to 16 or a method according to any of claims 17 to 18.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0081] In the following, preferred embodiments of the present invention are described with respect to the accompanying figures.

[0082] FIG. 1 is a schematic perspective cut view of a dual mass dog collar;

[0083] FIG. 2 is a schematic cut view of a gearbox comprising a dual mass dog collar;

[0084] FIG. 3 is a schematic cut view of a gearbox comprising a dual mass dog collar;

[0085] FIG. 4 gives a schematic illustration of a gearbox comprising two dual mass dog collars;

[0086] FIG. 5 gives a schematic illustration of individual components of a an alternative dual mass dog collar;

[0087] FIG. 6 gives a schematic illustration of individual components of a an alternative dual mass dog collar;

[0088] FIG. 7 is a schematic cut view of a gearbox for a marine engine comprising a dual mass dog collar;

[0089] FIG. 8 is a schematic alternative cut view of a gearbox for a marine engine comprising a dual mass dog collar;

[0090] FIG. 9 gives a schematic illustration of individual components of a gearbox for a marine engine comprising a dual mass dog collar;

[0091] FIG. 10 is an alternative method for securing individual components of a dual mass dog collar;

[0092] FIGS. 11A to 11B is an alternative dual mass dog collar comprising helical guiding means and a corresponding helical dog hub;

[0093] FIG. 12 is a dual mass dog collar comprising damping elements;

[0094] FIG. 13 gives a schematic illustration of individual components of a gearbox for a marine engine comprising a dual mass dog collar and helical guiding means;

[0095] FIG. 14 gives a schematic illustration of a gearbox comprising a dual mass dog collar and helical guiding means;

[0096] FIG. 15 gives a schematic illustration of a gearbox for an inboard marine engine comprising two dual mass dog collars;

[0097] FIG. 16 gives a schematic illustration of individual components of a dual mass dog clutch comprising a dual mass dog hub;

[0098] FIGS. 17A to 17E gives a schematic illustration of a gear ratio changing sequence;

DETAILED DESCRIPTION

[0099] As will become apparent from the following, the present application allows to provide a dual mass dog clutch comprising either at least one dual mass dog collar or a dual mass dog hub, for a gearbox, that minimizes the required time for a gear changing action, provides less wear and tear to the engaging components and reduces the emitted noise.

[0100] FIG. 1 demonstrates a dual mass dog collar 1 of dog clutch adapted in a gearbox. The dual mass dog collar is consisted by an inner part 40, an outer part 50, elastic elements connecting the inner part 40 and the outer part 50 and engagement means 60 that are adapted to engage a free, engageable gear wheel by interacting with the corresponding engagement means of the free engageable gear wheel.

[0101] The inner part 40 and the outer part 50 are angularly deflectable in relation to each other and the deflection is limited by the existence of the elastic elements.

[0102] Inner part 40 is provided as torque proof engaged with an assigned shaft by the engagement means 41 provided in the inner circumferential surface of the inner part 40. The engagement means 41 torque proof fix the inner part 40 directly to the shaft (may be torque proof engaged to the shaft via a dog hub which is torque proof engaged to the shaft).

[0103] Outer part 50 comprises engagement means 60, adapted to interact with the engagement means of a free, engageable gear wheel.

[0104] Upon engagement the otherwise free to rotate gear wheel, is torque proof engaged with the outer part 50.

[0105] Since the outer part 50 is connected to the inner part 40 via the elastic elements, the elastic elements will eventually by compressed, up to a point that the rotational forces and or torque from the outer part 50 will be transferred to the inner part 40.

[0106] Since the inner part 40 is torque proof engaged with an assigned shaft, by engaging different free, engageable gear wheel different gear ratios can be selected. The selection of different gear ratios is achieved by axially moving the dual mass dog collar along the assigned shaft.

[0107] The presented dual mass dog collar is axially moved as an entity, and the axial movement takes place by a corresponding shifting fork movement. The shifting fork is coupled to the outer part by the respective shifting fork coupling 53, positioned on the outer circumferential surface of the outer part 50.

[0108] The engagement means 60 are provided in both faces of the outer part 50. Therefore engagement means 60a face one free, engageable gear wheel and engagement means 60b face another. As a result dual mass dog collar 1 can be received in between two free, engageable gear wheels.

[0109] The specific shape/form of the engagement means 60 can vary and the presented one is not restrictive. Therefore the engagement means 60 can be protrusions, cavities or a combination of both, with a respective formation in the engagement means of the free, engageable gear wheels.

[0110] The number of the engagement means 60 and the number of the engagement means of the free, engageable gear wheels, do not necessarily have to match. The engagement means provided as cavities may be greater in number than the corresponding engagement means provided as protrusions.

[0111] As mentioned above, the inner part 40 is coupled to the outer part 50 by means of at least two elastic elements. In the presented section cut only the softer elastic element 70 can be seen but a second elastic element is also provided, with the two elastic elements being concentrically positioned, with the one positioned partially arranged within the other, with the proposed positioning not being restrictive.

[0112] Both inner part 40 and outer part 50 comprise elastic element supports, with the inner elastic element supports 42 being visible in the demonstration. Inner elastic element supports 42 are provided as two elastic element supports 42a, 42b with a “gap” in between them in which the outer elastic element support (not visible in this section cut) can be housed.

[0113] Finally secure rings 30 are provided, securing the inner part 40 and the outer part 50 in place, with the ability to be angularly deflectable in relation to each other, but axially movable as one.

[0114] FIG. 2 demonstrates a section cut of a gearbox comprising a dual mass dog collar.

[0115] The presented gearbox comprises an input shaft 10, supporting input gear wheels (drive wheels) 110, 120 which are torque proof engaged with the shaft, and an output shaft 20, supporting output gear wheels 210, 220 (driven wheels).

[0116] Output gear wheels 210, 220 are provided as free, engageable gear wheel, not transferring torque when being unengaged. The engagement takes place via the provided dual mass dog collar 1 “sandwiched” in between the output gear wheels 210, 220 (in an alternative configuration, shaft 20 and output gear wheels 210, 220 could be drive shaft/gear wheels and shaft 10 and gear wheels 110, 120 could be driven).

[0117] The input shaft 10 comprises engagement means 201 adapted to permanently torque proof fix the inner part 40 of the dual mass dog collar 1. Although the inner part 40 is provided as torque proof engaged with the shaft 20, it has the ability to be axially moved, engaging and disengaging the desired output gear wheel 210, 220.

[0118] Input gear wheel 110 constantly meshes with output gear wheel 210, and input gear wheel 120 constantly meshes with output gear wheel 220, therefore defining two gear ratios.

[0119] As it is obvious the gearbox may comprise more gear ratios with an analogous layout.

[0120] The dual mass dog collar adopted in this configuration is the one presented in FIG. 1.

[0121] In this section cut the two elastic elements inside the dual mass dog collar 1 can be seen. More specifically the selected exemplary layout comprises two spring elements housed in a single compartment formed by the inner part 40 and the outer part 50, with the two spring elements being positioned the one within the other.

[0122] The spring elements, comprise different spring constant in relation to each other. The first spring element 70 has a smaller spring constant in relation to the spring constant of the second elastic element 80. Therefore the first spring element 70 is softer and the second spring element 80 is stiffer.

[0123] Finally the engagement means 90 provided on a face of the free, engageable gear wheels can be seen. Since the engagement means 60 are provided as protrusions, the engagement means 90 are provided as cavities, having a corresponding formation matching the formation of the protrusions.

[0124] FIG. 3 presents a section cut of the gearbox presented in FIG. 2.

[0125] In this section cut, a more clear view of the dual mass dog collar 1 can be seen.

[0126] More particularly the specific form of the inner part 40, the outer part 50 and the layout of the elastic elements 70, 80.

[0127] Inner part 40 and outer part 50 have a common rotational axis and the inner part 40 is at least partially arranged within the outer part 50.

[0128] The first softer spring element 70 is partially arranged within the second elastic element 80 and protrudes out of the second elastic element 80 on a front face. As a result, the first softer spring element 70 is longer than the second elastic element 80.

[0129] The first softer spring element 70 is in constant contact with both the inner part 40 and the outer part 50, and is initially deformed upon deflection of either of the inner or the outer part.

[0130] The deformation of the second stiffer spring element 80 takes place after the complete engagement of the assigned free, engageable gear wheel, and as the angular deflection of either the inner part 40 or the outer part 50 progresses.

[0131] The stiffer spring element 80 is the one that transfers the significant amount of the occurring load and the softer spring element 70 is the one that assists with the engagement, allowing a smooth, complete engagement prior to the load transfer.

[0132] Inner elastic element support 42 and outer elastic element support 52 are provided, supporting the elastic elements 70, 80.

[0133] As mentioned before, input gear wheels are torque proof fixed gear wheels and as a result input shaft 10 provides engagement means 101, engaging the inner circumferential surface of the input gear wheels and thereby torque proof fix (same angular velocity) said gear wheels to the shaft.

[0134] In this demonstration the dual mass dog collar is positioned directly on top of the shaft. It is going without saying that the dual mass dog collar could be positioned on top of a dog hub, with the dog hub being torque proof engaged with the shaft.

[0135] FIG. 4 presents an alternative to the gearbox 2, where each free, engageable gear wheel has one dual mass dog collar, assigned to it.

[0136] Therefore the free engageable gear wheel 210 has the dual mass dog collar 1a assigned to it and the free engageable gear wheel 220 has the dual mass dog collar 1b assigned to it.

[0137] Both dual mass dog collars 1a, 1b, operate as described above in detail but in this configuration can be moved independently in relation to each other. Therefore for example the dual mass dog collar 1a can maintain its axial position while the dual mass dog collar 1b is axially moved.

[0138] As it is obvious only the one face of the dual mass dog collar, facing the assigned free, engageable gear wheel, comprises engagement means.

[0139] FIG. 5 presents a yet another alternative to the dual mass dog collar 1 presented in FIGS. 1 to 3.

[0140] The difference between the previously described configurations is that the elastic elements now comprise a rubber element as a second stiffer elastic element 80. The first softer elastic element 70 is again a spring element and as a result the elastic elements comprise different types of elastic elements (a spring element and a rubber element).

[0141] In addition the two elastic elements are not positioned the one within the other but in a position where the first, softer, elastic element 70 is positioned “on top” of the second, stiffer elastic element 80.

[0142] FIG. 6 presents a yet another alternative to the dual mass dog collar 1.

[0143] In this alternative, the dual mass dog collar 1 comprises engagement means 60 on one face of the outer part 50 and their position is on an inner circumferential surface instead of a front face.

[0144] Due to the fact that the engagement means 60 are provided on one face of the outer part 50 and not on both, every free, engageable gear wheel comprises a single dual mass dog collar and there are no free, engageable gear wheels sharing a single dual mass dog collar.

[0145] Therefore the movement of each dual mass dog collar can be independent in relation to the movement of the other dual mass dog collars.

[0146] In addition in comparison to the alternative presented in FIG. 5, the second stiffer elastic element 80 is positioned on top of the first softer spring element 70.

[0147] FIG. 7 and FIG. 8 present sectional views of a gearbox 2′ of an outboard or inboard/outboard motor, according to an embodiment of the invention. As can be seen, the gearbox 2′ is consisted by one bevel pinion 110, a first bevel gear 210 and a second bevel gear 220. Both the first and the second bevel gears 210, 220 are constantly meshed with the bevel pinion 110, and the main axis of the bevel gears and the bevel pinions, form a 90° angle.

[0148] Bevel pinion 110 is torque proof engaged with a drive shaft 10 that receives power from the engine (drive pinion). Bevel gears 210, 220 are assigned to the prop shaft 20 which has a marine propeller torque proof engaged with the shaft in one end.

[0149] Both bevel gears 210, 220 are assigned to the prop shaft 20 but are not constantly torque proof engaged with the prop shaft 20 and therefore are free to rotate when not engaged with the shaft.

[0150] The torque proof connection of bevel gears 210, 220 to the prop shaft 20 is achieved by the outer part 50 of the dual mass dog collar which is connected with the inner part 40 of the dual mass dog collar via elastic elements. Dual mass dog collar is positioned in between the bevel gears 210, 220 and is assigned to both bevel gears. The inner part 40 of the dual mass dog collar is torque proof engaged with the assigned shaft but has the ability to be moved axially.

[0151] The outer part 50 of the dual mass dog collar has a shifting fork coupling 53 which is coupled to the throttle lever that controls the axial position of the dual mass dog collar. By moving the throttle lever in the according position, dual mass dog collar engages either the first bevel gear 210 or the second bevel gear 220. Additional dual mass dog collar may not interact with any of the divided bevel gears 210, 220 by staying in a neutral position in between the bevel gears 210, 220.

[0152] The dual mass dog collar has engagement means 60a, 60b facing each bevel gear 210, 220. As can be seen engagement means 60a are assigned to divided bevel gear 210 which comprises corresponding engagement means goa and engagement means 60b are assigned to the divided bevel gear 220 which comprises corresponding engagement means 90b. In addition, preferably, both the engagement means 90a, 90b of the first and second bevel gears 210, 220 and the engagement means 60a, 60b of the dual mass dog collar, will be consisted by a great number of elements (e.g. teeth). This is preferred due to the fact that a collision between the engagement means 60a, 60b and the front face of the engagement means 90a, 90b of the bevel gears 210, 220 is not desired, and therefore a great number of elements (e.g. teeth) is preferred with each element (e.g. teeth) having a pointed face which facilitates the engagement. When the engagement means 60a, 60b and the engagement means 90a, 90b meet, the significant compression of the softer spring element 70 will begin. In addition the provision of a great number of engagement means, in both the dual mass dog collar and in the bevel gears, decreases the demanded tooth depth of the engagement means.

[0153] Therefore it is made clear that the decreased occurred inertia (due to the fact that initially upon engagement, only the outer part 50 of the dual mass dog collar takes part in the engagement/gear selection) accompanied by the existence of the softer spring element 70, result in a quicker and smoother gear change.

[0154] Bevel gears 210, 220 have a bevel gear teething on its outer surface which meshes with the bevel pinion teething of the bevel pinion 110.

[0155] Inner/outer part of the dual mass dog collar are coupled by two elastic elements where the set is consisted by one spring element 70 that has a smaller spring constant and protrudes on a front face of a second elastic element 80 that has a greater spring constant. In the presented illustration, springs are positioned concentrically in relation to each other with the first spring element protruding out of the second elastic element on a front face, and are housed in a spring compartment formed in between the inner part 40 and outer part 50. As mentioned before each spring consisting the set of springs can be positioned in a separate compartment or can be positioned the one on top of the other. The inner part 40 and the outer part 50 have the ability to deflect angularly in relation to each other up till the set of elastic elements is fully loaded. When the set of elastic elements is fully loaded both the inner part 40 and the outer part 50 rotate with the same angular velocity.

[0156] FIG. 9 exemplary demonstrates individual parts of the proposed gearbox of an outboard motor. In this figure a more clear view of the parts consisting the proposed gearbox used in marine engines can be seen.

[0157] As mentioned before the dual mass dog collar is torque proof engaged with the prop shaft 20 but has the ability to slide axially depending on the position of the throttle lever, engaging and disengaging the desired gear ratio. The engagement to the shaft takes place with the provision of an engagement surface 41 on the inner cylindrical face of the dual mass dog collar that is in accordance with the engagement means 201 of the prop shaft 20 which extends for a suitable length in relation to the distance of the first and second bevel gears 210, 220.

[0158] When the first gear ratio is desired, an according movement of the throttle lever, positions the dual mass dog collar towards the position of the first bevel gear 210. As a consequence the engagement means 60a of the dual mass dog collar interact with the engagement means goa positioned on the front surface of the bevel gear 210, facing the engagement means 60a, and therefore forcing the dual mass dog collar to rotate. Since the dual mass dog collar is torque proof engaged with the prop shaft 20, prop shaft 20 also rotates.

[0159] When the outer part 50 of the dual mass dog collar is not engaged with the bevel gear 210 the softer spring of the outer part of dual mass dog collar is considered not to be deformed (the occurring deformation is negligible) and the stiffer spring is also not deformed since is “shorter” in relation to the softer spring and the deflection of the outer part of the divided bevel gear in relation to the inner part is negligible.

[0160] When the outer part 50 of the dual mass dog collar begins to engage to the bevel gear 210 by the interaction of the engagement means 60a of the outer part 50, with the engagement means goa of the bevel gear 210, the rotational force is transferred from the outer part to the softer spring element and therefore the deformation of the softer spring element begins, since it was considered not to be deformed. Due to the fact that the softer spring element has a small spring constant and the outer part 50 has small inertia, the engagement takes place smoothly. As it is obvious the softer spring element is deformed initially and after the completion of the engagement, the deformation of the stiffer elastic element follows accompanied by the continuance in deformation of the softer spring element. When the stiffer elastic element begins to bear load in a progressive manner, the substantial amount of power begins to be transferred. When the load is fully borne by the set of elastic elements, both the inner part 40 and the outer part 50 will rotate with the same angular velocities.

[0161] FIG. 10 demonstrates an alternative way of securing the inner part 40 and the outer part 50 of the dual mass dog collar 1 when the dual mass dog collar 1 is axially moved as an entity.

[0162] In this alternative, the two parts are secured with the help of securing pin 35, which is received in a cavity on the outer circumferential surface. The securing pin 35 may have a spiral first part that is bolted to the outer part 50 and a pin part that secures the inner part 40 in place.

[0163] In order to secure the inner part 40 in place, groove 36 is provided, and therefore the inner part 40 although is secured (cannot be independently axially moved in relation to the outer part) can be angularly deflected in relation to the outer part 50 and vice versa.

[0164] As it is obvious there are many ways in which the inner part 40 and the outer part 50 can be secured with the two presented not being restrictive.

[0165] FIG. 11A and FIG. 11B, presents an alternative design where the inner part 40 comprises helical engagement means 41 and is assigned to a dog hub comprising corresponding helical engagement means 201.

[0166] In alternative designs, engagement means 41, 201 can comprise a helical groove or protrusion that is adapted to guide the inner part 40 helically i.e. in combined axial and rotational movement.

[0167] In FIG. 12 an alternative dual mass dog collar 1 is presented.

[0168] In this alternative the inner elastic element supports 42 comprise a damping element 43 that damps the return of the outer part 50 when it stops being engaged.

[0169] Damping element 43a is on the inner face of the elastic element support 42a and damping element 43b is on the inner face of the elastic element support 42b, facing the damping element 43a. The rest of the individual components are the same as the ones described in the previous layouts.

[0170] As it is obvious the position of the damping surfaces is exemplary and many other positions can be selected.

[0171] In FIG. 13 a demonstration showing the relative additional angular velocity of the dual mass dog collar can be seen, when helical engagement means 201 are adapted.

[0172] More specifically the black curved arrows show the direction of the rotation of the components and the straight arrows show the direction of the axial displacement of the dual mass dog collar 1.

[0173] Therefore when the dual mass dog collar 1 is moved towards the bevel gear 210 rotates with an opposite direction of rotation in relation to the direction of rotation of the bevel gear wheel.

[0174] At the same time, the softer spring element compresses in the opposite direction, in relation to the direction of rotation of the bevel gear wheel and therefore additional time for the engagement is provided.

[0175] When the engagement between the bevel gear 210 and the outer part 50 of the dual mass dog collar initiates, the bevel gear 210 “pulls” the dual mass dog collar 1, assisting and securing the engagement.

[0176] The same goes when the dual mass dog collar 1 is moved towards the bevel gear 220.

[0177] FIG. 14 demonstrates a gearbox which may for example be adopted in an electric vehicle comprising two gear ratios and the engagement means 201, 41 are helically shaped. As mentioned before this helical formation provides additional angular velocity to the dual mass dog collar 1 upon axial movement.

[0178] As a result when the dual mass dog collar 1 is axially moved towards the free, engageable gear wheel 220, due to the selected helix angle, it has an additional rotation in the same direction of rotation as the engageable gear wheel 220 (the direction of rotation is given by the arrows on the top part of the figure). As a result the absolute angular velocity of the dual mass dog collar is greater than the absolute angular velocity of the shaft when the gear changing action takes place from a first gear ratio to a second gear ratio.

[0179] When the dual mass dog collar 1 is moved towards the engageable gear wheel 210, the absolute angular velocity of the dual mass dog collar is smaller than the absolute angular velocity of the shaft when the gear changing action takes place from a second gear ratio to a first gear ratio.

[0180] This feature, assists in smaller differences between the angular velocities of the engaging parts (dual mass dog collar and gear wheel).

[0181] It is worth mentioning that when the gearbox operates in a first gear ratio, the gear selecting mechanism should secure the dual mass dog collar in place, due to the fact that the dual mass dog collar wants to be disengaged. In contrast when the second gear ratio is selected the engagement is granted.

[0182] FIG. 15 demonstrates a gearbox adopted for example in an inboard marine engine.

[0183] The gearbox is consisted by two input shaft 10a and 10b, supporting input gear wheels 110a, 110b which are torque proof engaged with their assigned shafts and constantly mesh.

[0184] In addition the input shaft 10a supports the free, engageable gear wheel 110c and the input shaft 10b supports the free, engageable gear wheel 110d.

[0185] The free engageable gear wheels 110c, 110d mesh with the output gear wheel 220 which is torque proof engaged with the output shaft 20. At the end of the output shaft 20 a propeller may be torque proof engaged with the shaft.

[0186] Dual mass dog collar 1a is assigned to the free engageable gear wheel 110c. The dual mass dog collar 1a is concentrically positioned and torque proof engaged with the input shaft 10a but has the ability to be axially movable in order to engage or disengage the assigned gear wheel 110c.

[0187] Similarly the dual mass dog collar 1b is assigned to the free engageable gear wheel 110d.

[0188] Therefore by axially moving the desired dual mass dog collar, a gear ratio is selected and the direction of rotation of the output gear wheel 220 (and as a consequence the direction of rotation of the output shaft 20 and the direction of rotation of the propeller) changes.

[0189] FIG. 16 presents a dual mass dog hub 3. The dual mass dog hub 3 has an analogous operation and a similar layout to the a dual mass dog collar.

[0190] In this configuration the hub is provided as a dual mass dog hub and the dog collar is torque proof engaged to the dual mass dog hub and axially moved towards or away the assigned gear wheels, in order to engage or disengage the desired free, engageable gear wheel.

[0191] The presented dual mass dog hub (3) comprises an inner part 340, an outer part 350. Therefore the inner part 340 and the outer part 350 are axially fixed to the assigned shaft and the dog collar is axially movable. The inner part 340 is torque proof engaged with the assigned shaft via the engagement means 341 positioned in the inner circumferential surface. The inner part 340 and the outer part 350 have a common rotational axis and are arranged concentrically to the assigned shaft. Further, the inner part 340 is at least partially arranged within the outer part 350 and the inner part 340 is coupled to the outer part 350 by means of two elastic elements 370, 380 (a first and a second elastic element) with different spring constants in relation to each other, arranged in a parallel configuration, so that the inner part 340 is arranged angularly deflectable with respect to the outer part 350 around the common rotational axis (and vice versa).

[0192] The elastic elements can be spring elements, such a torque springs or a spiral springs, torsional springs, or any other elastic elements such as rubber blocks etc. Further, different types of elastic elements can be combined in a dual mass dog clutch comprising a dual mass dog hub in order to achieve a desired spring characteristic.

[0193] The two elastic elements 370, 380 may be positioned within one elastic element compartment, formed by the inner part 340 and the outer part 350. Alternatively the elastic elements can be positioned in separate compartments but in any case the two elastic elements 370, 380 will be positioned in an arrangement that the first elastic element 370, having a smaller (in relation to the second elastic element 380) spring constant, is initially deformed upon deflection of either the inner or the outer part of the dual mass dog hub (providing the required time in order to achieve a complete engagement before the second spring element 380 begins to bear load), and the deformation of the second elastic element 380 (having a greater spring constant in relation to the first spring element 370) follows as the deflection progresses. In particular, the spring compartment can be a closed compartment. Alternatively, the spring compartment may be an open compartment that allows heat exchange and a facilitated maintenance of the springs.

[0194] The dog collar is axially movable along and on top of the assigned dual mass dog hub, with the dog collar being torque proof engaged with the outer part 350 of the dual mass dog hub, and comprises engagement means 320a on one face of the dog collar and engagement means 320b on the opposite face. The torque proof engagement of the dog collar with the outer part 350 takes place with the provision of the engagement means 360 on the outer circumferential surface of the outer part 350, that at the same time torque proof engage and guide the dog collar. The engagement between the dog collar of the dual mass dog clutch 3 and the free, engageable gear wheel is temporally and is achieved with the help of engagement means 320 (e.g. teeth) that are adapted to engage with the engagement means of the free, engageable gear wheel.

[0195] Accordingly the dog collar can transfer rotational force and/or torque to the outer part 350 and via the at least two elastic elements 370, 380 to the inner part 340. Due to the fact that the inner part 340 of the dual mass dog hub is torque proof engaged with the shaft rotational forces and/or torque can be transferred from the free, engageable gear wheel to the shaft and vice versa.

[0196] In this demonstration, each of the elastic elements 370, 380 is housed in a different compartment.

[0197] As can be seen, the first softer spring element 370 is housed in a compartment defined by the inner elastic element support 342a and the second stiffer elastic element 380 in a compartment defined by the inner elastic element support 342b. In addition securing rings 330 secure in axial place the inner part 340 and the outer part 350, and a shifting fork coupling 353 is provided in order to axially move the dog collar.

[0198] Again in this alternative the position of the elastic elements is in a parallel configuration and the first softer spring element 370 is the one that is initially deformed.

[0199] It is going without saying that the arrangement for housing the spring elements 370, 380 is not restrictive and both can be housed in a single elastic element compartment with the one spring element being received within the other spring element.

[0200] In this presentation the dog collar comprises engagement means in both faces. It is going without saying that the engagement means could be comprised only in one face but in that case two dog collars should be adopted, one for each free, engageable gear wheel.

[0201] As a person skilled in the art understands, the operation is exactly analogous to the previously described one for the dual mass dog collar 1, with all the mentioned alternative proposals being able to be adapted to the dual mass dog hub.

[0202] In FIGS. 17A to 17E a schematic illustration of a gear ratio changing sequence is given with the main goal of the illustration being the depiction of the behavior of the elastic elements for a continuously power transfer.

[0203] As can be seen gear ratio n is consisted by the torque proof fixed gear wheel 110 which meshes with the free, engageable gear wheel 210 which has the dual mass dog collar 1a assigned to it.

[0204] Similarly, gear ratio n+1 is consisted by the torque proof fixed gear wheel 120, which meshes with the free, engageable gear wheel 220 which has the dual mass dog collar 1b assigned to it.

[0205] Dual mass dog collars 1a, 1b comprise engagement means only in one face and therefore are able to be moved independently in relation to each other.

[0206] In FIG. 17A gear ratio n is selected and 100% of the torque is delivered through gear ratio n. As can be seen both the elastic elements inside the dual mass dog collar 1a are completely compressed and the elastic elements inside the dual mass dog collar 1b are completely decompressed.

[0207] In FIG. 17B a command is given in order to engage/disengage the free, engageable gear wheels and upon the beginning of the engagement of gear ratio n+1, the first, softer elastic element begins to compress. Since the first softer elastic elements have a very small spring constant and since the inertia is very small, a smooth easy engagement can be achieved.

[0208] In FIG. 17C the second, stiffer elastic element of the dual mass dog collar 1b, begins to compress and as a consequence the second, stiffer elastic element of the dual mass dog collar 1a begins to decompress. For example 0.1% of the occurring torque is delivered through gear ratio n+1 and 99.9% is delivered through gear ratio n.

[0209] As time passes and as can be seen in FIG. 17D, more torque is being delivered through gear ration n+1 and less through gear ratio n.

[0210] As can be seen as the time passes, the elastic elements of the dual mass dog collar 1b are more compressed and the elastic elements of the dual mass dog collar 1a are less compressed.

[0211] For example in FIG. 17D each gear ratio delivers 50% of the torque.

[0212] In FIG. 17E 100% of the torque is delivered through gear ratio n+1 and as a consequence the elastic elements of the dual mass dog collar 1b are fully compressed and the elastic elements of the dual mass dog collar 1a are fully decompressed.

[0213] From the above it is made clear that during a gear changing action the torque transfer is progressive and there is not a single moment where there is no torque delivery to the output shaft.

[0214] As a person skilled in the art understands, the operation is analogous to the previously described one, either when the gearbox comprises a dual mass dog collar or a dual mass dog hub.

[0215] The above described gearboxes comprising, allow a quick and smooth engagement when a gear changing action takes place, either by comprising at least one dual mass dog collar or a dual mass dog hub.

[0216] As it is obvious all of the described configurations are exemplary and not restrictive and are presented in order to explain and highlight the features of the proposed innovation.

LIST OF REFERENCE SIGNS

[0217] 1 dual mass dog collar [0218] 2 gearbox [0219] 3 dual mass dog clutch [0220] 10 input shaft/drive shaft [0221] 20 output shaft/prop shaft [0222] 30 securing ring [0223] 35 securing pin [0224] 36 groove [0225] 40 inner part [0226] 41 engagement means [0227] 42 elastic element support [0228] 43 damping element [0229] 50 outer part [0230] 52 elastic element support [0231] 53 shifting fork coupling [0232] 60 engagement means [0233] 70 elastic element/spring element [0234] 80 elastic element/spring element [0235] 90 engagement means [0236] 101 engagement means [0237] 110 gear wheel/bevel pinion [0238] 120 gear wheel [0239] 201 engagement means [0240] 210 gear wheel/bevel gear [0241] 220 gear wheel/bevel gear [0242] 320 engagement means [0243] 330 securing ring [0244] 340 inner part [0245] 342 inner elastic element support [0246] 350 outer part [0247] 353 shifting fork coupling [0248] 360 engagement means [0249] 370 elastic element/spring element [0250] 380 elastic element/spring element