Gearbox and disassembly method for disengaging a drive shaft in such a gearbox

Patent metadata

Field	Value
Publication number	US-10837496-B2
Application number	US-201414908508-A
Country	US
Kind code	B2
Filing date	Jul 29, 2014
Priority date	Jul 29, 2013
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A gearbox has a main unit and a secondary unit provided with respective casings of respective gear transmissions and with respective hollow shafts connected by means of a drive shaft; the secondary unit transfers motion between two axes forming an angle of less than 180° and which can be removed after having released the drive shaft; the drive shaft is engaged in an angularly fixed and axially sliding manner to the hollow shafts and is axially locked, at least in one direction, by means of an axial retaining device, which is releasable; the axial retaining device is coupled to one of the hollow shafts, at an axial end which is facing towards the other of the hollow shafts; at least one opening may be formed between the two casings, so as to access such an axial end and release the axial retaining device.

First claim

The invention claimed is:

1. A gearbox comprising:
a main unit comprising:
a) a first casing;
b) a first gear transmission; and
c) a first hollow shaft defining a motion input for said first gear transmission;

a secondary unit comprising:
a) a second casing;
b) a second gear transmission defining a transmission of motion between two axes forming an angle of less than 180°; and
c) a second hollow shaft defining a motion output for said second gear transmission;

a drive shaft comprising a first and a second clutch portion, which respectively engage said first and second hollow shafts in an angularly fixed and axially slidable manner to transmit motion from said second gear transmission to said first gear transmission;
axial retaining means to prevent said drive shaft from translating axially in at least one of the two directions; said axial retaining means being releasable and comprising an axial shoulder supported in fixed position by a portion which is defined by an axial end of one of said first and second hollow shafts and faces the other of said first and second hollow shafts;
opening means provided between said first and second casing to access said axial end and release said axial retaining means;
wherein said axial retaining means further comprise an external radial projection, which is part of said drive shaft, is arranged in an intermediate position between said first and second clutch portion and axially faces said axial shoulder so as to prevent said drive shaft from translating axially towards said axial end.

2. The gearbox according to claim 1 , wherein the profiles in a circumferential direction of said external radial projection and of said axial shoulder are shaped so as to enable the drive shaft of sliding axially with respect to said axial shoulder in both directions after a relative rotation.

3. The gearbox according to claim 2 , wherein said axial retaining means comprise a ring, which comprises said axial shoulder, is arranged around a first intermediate portion of said drive shaft and is releasably fixed to said axial end.

4. The gearbox according to claim 3 , wherein said ring has a hole spline defining said axial shoulder.

5. The gearbox according to claim 3 , wherein said ring is coupled to said axial end in an axially sliding and angularly fixed manner; said axial retaining means comprising an axial locking means that keep said ring in an axially fixed position with respect to said axial end.

6. The gearbox according to claim 3 , wherein said axial end is axially delimited by an end face and radially delimited by an inner surface; said ring comprising:
an annular wall engaging said inner surface in an angularly fixed and axially sliding manner,
an external flange, which projects from an axial edge of said annular wall and has an external diameter greater than the internal diameter of said end face.

7. The gearbox according to claim 1 , wherein said external radial projection is defined by an axial toothing identical to and aligned with a shaft spline defined by said first clutch portion.

8. The gearbox according to claim 1 , wherein said axial retaining means are configured so as to prevent the axial translation of said drive shaft only towards said axial end.

9. The gearbox according to claim 1 , wherein said other of said first and second hollow shafts comprises an inner projection, which is axially spaced from said drive shaft and axially faces said drive shaft so as to define a limit stop shoulder.

10. The gearbox according to claim 1 , wherein said drive shaft comprises a second intermediate portion provided with a further external radial projection having dimensions and axial position such as to prevent back to front assembly of said gearbox.

11. The gearbox according to claim 1 , wherein said opening means are defined by an annular shell, which joins said first and second casing and is openable or removable.

12. The gearbox according to claim 11 , wherein said annular shell comprises at least one closing element that is axially slidable to open an access towards the inside of said annular shell.

13. A disassembly method for disengaging a drive shaft in a gearbox made according to claim 1 , the method comprising the steps of:
forming at least one opening between said first and second casing;
accessing said axial end through said opening to release said axial retaining means without disassembling said drive shaft; the release of said axial retaining means comprising the following steps:
a) partly extracting said drive shaft from said axial end so as to axially space said external radial projection from said axial shoulder;
b) disengaging said axial shoulder from said axial end;
c) rotating said axial shoulder, with respect to said drive shaft, so as to prevent interference in axial direction with respect to said external radial projection;

axially translating said drive shaft towards said axial end, by operating through said opening, so as to disengage said drive shaft from said other of said first and second hollow shaft, without disassembling said drive shaft.

14. The disassembly method according to claim 13 , wherein disengagement of said axial shoulder is carried out by:
releasing axial locking means, and
axially extracting said axial shoulder from said axial end.

15. The disassembly method according to claim 13 , wherein, after rotation of said axial shoulder and before translation of said drive shaft, said axial shoulder is moved away from said axial end, with an axial sliding along said external radial projection.

Assignees

• Ge Avio Srl

Inventors

• Kowalewski Tomasz
• Borra Ivan
• Bragallini Gian Mario
• Giordano Vincenzo

Classifications

• F02C7/32 Primary

  Arrangement, mounting, or driving, of auxiliaries · CPC title

• F16D1/08

  with clamping hub; with hub and longitudinal key · CPC title

• F16H1/14

  comprising conical gears only · CPC title

• F16D1/0876

  with axial keys and no other radial clamping · CPC title

• F16D1/10

  Quick-acting couplings in which the parts are connected by simply bringing them together axially · CPC title