A transmission having a gear with conical coaxial front gears

Abstract

A transmission (10) with gears, comprising a driving wheel (4) and a driven wheel (3) rotating about a common axis (13), and a cursor (9) arranged transversely of the axis (13) and sliding relative thereto, the wheels (4, 3) being provided with respective crown gears (5A, 5B) arranged on different diameters of the driving wheel (4) and the driven wheel (3), the crown gears (5A, 5B) being made of teeth projecting from the facing surfaces (21, 22) of the wheels (4, 3), and the cursor (9) being arranged transversely of the axis (13) and sliding relative thereto. ) is arranged at the end of the cursor (9) and further comprises two gears (7A, 7B) configured to rotate around an axis (19) of the cursor (9) and transmit motion from the driving wheel (4) to the driven wheel (3), each gear (7A, 7B) engages with a respective crown gear (5A, 5B) arranged on 20 different diameters of the driving wheel (4) and the driven wheel (3), and the cursor (9) slides inside a seat (15) made on the axis (13).

Description

[Technical field]

[0001] The invention relates to a transmission having coaxial face gears, in particular of conical shape. More particularly, the present invention provides a derailleur having gears with coaxial face gears to be applied in all uses requiring or preferring a coaxial wheel arrangement, such as for example for integration into the hub of a bicycle drive wheel. [Background technology]

[0002] Transmissions having gears are known in the art, particularly for use on bicycles. However, these known transmissions are not satisfactory and have the problems of being relatively bulky, heavy and complex, and of using mechanisms which are difficult to protect from dirt and have a consequential decrease in reliability. Summary of the Invention

[0003] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to solve the problems of the prior art mentioned above by providing a transmission having gears with coaxial face gears which is not bulky, simple to manufacture and reliable.

[0004] The above and other objects and advantages of the present invention, as will become apparent from the following description, are achieved by a transmission having gears with coaxial face gears such as that set out in claim 1. Preferred embodiments of the invention and non-obvious variants form the subject matter of the dependent claims.

[0005] It will be understood that all of the appended claims form an integral part of this specification. It will be immediately apparent that countless variations and modifications may be made to what is described (e.g., in terms of shape, size, arrangement, and parts having equivalent functions) without departing from the scope of protection of the invention, which emerges from the appended claims.

[0006] The invention will be better explained by some preferred embodiments of the invention given as non-limiting examples with reference to the attached drawings, in which: [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of one embodiment of a transmission having coaxial face gears in accordance with the present invention. [Diagram 2] FIG. 1 is a top view of one embodiment of a transmission having coaxial front gear wheels in accordance with the present invention. [Diagram 3] FIG. 1 is a cross-sectional view of one embodiment of a transmission having coaxial face gears in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] With reference to the drawings, a preferred embodiment of a transmission 10 with coaxial gear wheels of the present invention is shown and described. Such a transmission 10 comprises a driving wheel 4 and a driven wheel 3 rotating about an axle 13, for example a fixed axle, and a cursor 9 arranged transversely of the axle 13, preferably inside a seat 15 formed in the axle 13, and sliding relative thereto.

[0009] The gear wheels 4,3 preferably comprise respective crown gears 5A,5B arranged on different diameters of the driving wheel 4 and the driven wheel 3, said crown gears 5A,5B being made up of teeth protruding from facing surfaces 21,22 of the wheels 4,3.

[0010] The cursor 9 also comprises two gears 7A, 7B arranged at its ends, said gears 7A, 7B being preferably integral with each other and fixed to an axis 19 of the cursor 9 and configured to rotate about the axis 19 and transmit motion from the driving wheel 4 to the driven wheel 3, with each gear 7A, 7B engaging with a respective crown gear 5A, 5B arranged on different diameters of the driving wheel 4 and the driven wheel 3.

[0011] The surfaces 21, 22 of the driving wheel 4 and the driven wheel 3 are preferably of conical shape and inclined relative to their axis 13 by an angle a which is preferably equal to the angle of inclination of the axis 19 of the cursor 9, and crown gears 5A, 5B are arranged on said surfaces 21, 22, and preferably the driving wheel 4 and the driven wheel 3 are mirror surfaces.

[0012] In the first configuration of the transmission 10 with gears having coaxial front gear wheels of the invention, the shaft 13 is fixed and serves to support the rotation of the driving wheels 4 and the driven wheels 3 and to guide the sliding of the cursor 9.

[0013] Other configurations of the invention are possible and the functions of the components may be interchanged or used in any other way, for example the movable drive wheel 4, the fixed wheel 3, the axle 13 can rotate with the cursor 9, the two gears 7A, 7B behave like satellites, etc.

[0014] The operation of a transmission having coaxial front gear wheels will now be described in the first configuration of the invention shown in the drawings and described above. In this configuration, the driving wheel 4 and the driven wheel 3 are mirrored and each have four crown gears 5A, 5B, arranged on different diameters, made on surfaces 21, 22 inclined by an angle a equal to the angle of inclination of the axis 19 of the cursor 9, so as to allow the cursor 9 to slide and move radially relative to the wheels 4, 3 and to mesh with the crown gears 5A, 5B arranged on different diameters of the two wheels 4, 3, integral with each other, the first gear 7A being meshed with the driving wheel 4 and the second gear 7B being meshed with the driven wheel 3.

[0015] The angle a of inclination of the axis 19 of the cursor 9 allows the transmission to operate. In fact, the cursor 9 can slide along its axis 19 to affect a change of the ratio between the driving wheel 4 and the driven wheel 3, allowing the front gear 7A to mesh only with the crown 5A of the driving wheel 4, and the second gear 7B to mesh only with the crown 5B of the driven wheel 3, without interference with the driving wheel 4, as is clear from the drawing.

[0016] As a result, the driving wheel 4 transmits motion through one of the crowns 5A to the first gear 7A, which transmits motion to the second gear 7B, which finally transmits motion to the driven wheel 3 through one of the crowns 5B.

[0017] The transmission having gears with coaxial front gear wheels of the invention further comprises means, not shown in the drawings, for controlling the axis 19 of the cursor 9, which is configured to move the cursor 9 upwards or downwards along its axis 19 when a ratio is required, to move the cursor 9 a distance equal to the distance between the crowns 5A, 5B, thereby obtaining a change in the speed of rotation of the driven wheel 3 relative to the driving wheel 4, thereby increasing or decreasing the speed of the driven wheel 3 depending on the direction of movement 9 of the cursor.

[0018] In the configuration just described, there are four crown gears 5A, 5B, which make it possible to obtain four ratios, although the number of crown gears may vary according to the need for ratios and manufacturing techniques.

[0019] The cursor 9 is designed to be moved by a cursor movement mechanism which, according to a preferred embodiment, is housed in a central shaft 13 and is normally fastened to the chassis and therefore does not move. This movement, which is essential for changing the gear ratio, can be performed manually by levers, rack rods, gears, etc. (not shown), as well as by means of small electric motors or sliding magnets to automate the selection of the gear ratio.

[0020] Another important feature made possible by the embodiment described above is that the mechanism can be made completely closed and waterproof by installing, on the outer circumference between the conical wheels 3, 4, a tube (not shown) with a suitable gasket that in any case allows the free rotation of the mechanism and closes the intervening space between the wheels 3, 4. One of the conical wheels 3, 4 (4) is the driving wheel, receiving the motion to be transmitted, and the other (3) is the driven wheel, which, by means of a control system via the central shaft 13, becomes the carrier hub of the traction wheel of the means in which the transmission of the invention is used.

Claims

1. A transmission (10) having gears, A driving wheel (4) and a driven wheel (3) rotating about a common axis (13); a cursor (9) arranged transversely of said common axis (13) and sliding relative to said wheels (4, 3) with respective crown gears (5A, 5B) arranged on different diameters of said driving wheel (4) and said driven wheel (3); Equipped with said crown rings (5A, 5B) are made of teeth projecting from their surfaces (21, 22) facing said rings (4, 3); the cursor (9) further comprises two gears (7A, 7B) arranged at the end of the cursor (9) and configured to rotate about the axis (19) of the cursor (9) and to transmit motion from the driving wheel (4) to the driven wheel (3); each gear (7A, 7B) engaging with a respective crown gear (5A, 5B) located on a different diameter of said driving wheel (4) and said driven wheel (3); The cursor (9) slides inside a seat (15) formed on the shaft (13). Transmission (10).

2. The shaft (13) is fixed, The gears (7A, 7B) are integral with each other and fixed to the shaft (19) of the cursor (9). A transmission (10) according to claim 1, characterised in that

3. The surfaces (21, 22) of the driving wheel (4) and the driven wheel (3) are It is cone shaped, inclined at an angle (a) to their said axis (13), The crown gears (5A, 5B) are disposed on the surfaces (21, 22). A transmission (10) according to claim 1 or 2, characterised in that

4. The angle (a) of the surfaces (21, 22) is equal to the angle of inclination of the axis (19) of the cursor (9). A transmission (10) according to claim 3, characterised in that

5. The driving wheel (4) and the driven wheel (3) mirror each other A transmission (10) according to any one of claims 1 to 4, characterised in that

6. The shaft (13) It is fixed, It has the role of supporting the rotation of the driving wheel (4) and the driven wheel (3) and guiding the scrolling of the cursor (9). A transmission (10) according to any one of claims 1 to 5, characterised in that

7. The drive wheel (4) is movable, The driven wheel (3) is fixed, said axis (13) can rotate together with said cursor (9); The two gears (7A, 7B) act as satellites. A transmission (10) according to any one of claims 1 to 5, characterised in that

8. further comprising means for controlling said axis (19) of said cursor (9), configured to move said cursor (9) upwards or downwards along said axis (19) and to move said cursor (9) a distance equal to the distance between said crowns (5A, 5B) to obtain a change in the speed of said rotation of said driven wheel (3) relative to said driving wheel (4). A transmission (10) according to any one of claims 1 to 7, characterised in that

9. The cursor (9) is designed to be moved by a cursor movement mechanism, The cursor movement mechanism is housed in the central shaft (13), The movement of the cursor (9) is performed manually by a lever or rack rod or gear. A transmission (10) according to any one of the preceding claims, characterized in that

10. The cursor (9) is designed to be moved by a cursor movement mechanism, The cursor movement mechanism is housed in the central shaft (13), The movement of the cursor (9) is carried out automatically using small electric motors or sliding magnets. A transmission (10) according to any one of the preceding claims, characterized in that

11. The mechanism is completely closed and made waterproof by installing, on the outer circumference between the conical rings (3, 4), a tube equipped with a gasket which in each case allows the mechanism to rotate freely and closes the intervening space between the rings (3, 4). A transmission (10) according to any one of claims 8 to 10, characterized in that

Images