MULTI-RATIO GEARBOX HOUSING

• US 20140157954A1
• Filed: 08/15/2011
• Published: 06/12/2014
• Est. Priority Date: 08/15/2011
• Status: Active Grant

• Current Assignee: Volvo Lastvagnar AB (Volvo AB)
• Original Assignee: Volvo Lastvagnar AB (Volvo AB)
• Inventors: Zettergren, Lars
• Granted Patent: US 9,784,359 B2
• Time in Patent Office: Days
• US Class Current: 74/606.R
• CPC Class Codes: B22D 19/02 for making reinforced articles B22D19/14 takes precedence
• CPC Class Codes: F16H 2057/0206 for commercial vehicles, e.g. buses or trucks
• CPC Class Codes: F16H 57/021 Shaft support structures, e.g. partition walls, bearing eyes, casing walls or covers with bearings
• CPC Class Codes: F16H 57/032 characterised by the materials used
• CPC Class Codes: Y10T 74/2186 Gear casings

Abstract

A multi-ratio gearbox housing for a vehicle is made of light metal material and includes a first bearing seat having a cylindrical inner surface, and a reinforcement member having a first cylindrical inner surface surrounding the first bearing seat for reducing thermal radial expansion of the first bearing seat, the reinforcement member being of a material the coefficient of thermal expansion of which is less than the coefficient of thermal expansion of the light metal material of the housing. The reinforcing member is a cast-in insert arranged in the housing, and a radial distance between the first cylindrical inner surface and the cylindrical inner surface of the first bearing seat is substantially constant along circumferential lines of the first bearing seat, facilitating improved form stability of the cylindrical inner surface of the first bearing seat over the temperature operating range of the housing.

Claims

1. Multi-ratio gearbox housing for a vehicle, the housing being made of light metal material and comprising:

a first bearing seat having a cylindrical inner surface;

a reinforcement member having a first cylindrical inner surface surrounding the first bearing seat for reducing thermal radial expansion of the first bearing seat, wherein the reinforcement member being of a material the coefficient of thermal expansion of which is less than the coefficient of thermal expansion of the light metal material of the housing

wherein the reinforcing member being cast-in insert arranged in the housing, wherein a radial distance between the first cylindrical inner surface and the cylindrical inner surface of the first bearing seat is substantially constant along circumferential lines of the first bearing seat, facilitating improved form stability of the cylindrical inner surface of the first bearing seat over the temperature operating range of the housing.

2. Housing according to claim 1, wherein the housing comprising also a second bearing seat having a cylindrical inner surface, a first axis of the first bearing seat being parallel with a second axis of the second bearing seat, the reinforcement member having also a second cylindrical inner surface surrounding the second bearing seat for reducing thermal radial expansion of the second bearing seat, and for improving an interrelating dimensional stability of the first and second bearing seats, a radial distance between the second cylindrical inner surface and the cylindrical surface of the second bearing seat is constant along circumferential lines of the second bearing seat, facilitating improved form stability of the cylindrical inner surface of the second bearing seat over the temperature operating range of the housing.

3. Housing according to claim 1, wherein the housing comprising a first wall that extend substantially perpendicular to the first axis of the first bearing seat, wherein the first and/or second bearing seat is arranged in the first wall.

4. Housing according to claim 3, wherein the reinforcing member being cast-in into the first wall of the housing.

5. Housing according to claim 1, wherein the light metal material is aluminium-based light alloy, or magnesium-based light alloy, or titanium-based light alloy, wherein the reinforcement member is made of steel or cast iron.

6. Housing according to claim 1, wherein the radial distance between the first cylindrical inner surface and the cylindrical inner surface of the first bearing seat and/or between the second cylindrical inner surface and the cylindrical inner surface of the second bearing seat being within the range of 0.5 mm-50 mm, preferably within 1 mm-25 mm, and more preferably within 2 mm-15 mm.

7. Housing according to claim 1, wherein an axial bearing retainer is secured to the first wall by means of at least one fastening device, which is inserted in a fastening hole formed in the first wall and in the reinforcement member, the fastening hole of the first wall is substantially coaxial with the fastening hole of the reinforcement member, and a diameter of the fastening hole of the reinforcement member is larger than a diameter of the fastening hole of the first wall.

8. Housing according to claim 1, wherein the reinforcement member having a first cylindrical inner surface that completely surrounds the first bearing seat, and/or in that the reinforcement member having a second cylindrical inner surface that completely surrounds the second bearing seat.

9. Housing according to claim 1, wherein the reinforcement member being substantially completely embedded within the first wall.

10. Housing according to claim 1, wherein the reinforcement member is not machined after being cast-in in the first wall.

11. Housing according to claim 1, wherein a cross-section of the reinforcement member in an axial plane of the first and/or second cylindrical inner surface has relatively large height/width-ratio for providing a high radial strength, preferably at least 2:

1.

12. Housing according to claim 1, wherein the reinforcement member is made in a single piece.

13. Multi-ratio gearbox comprising a housing according to claim 1, wherein the gearbox comprising at least a first and a second shaft with substantially fix and substantially parallel axes, the housing having at least a first wall that extends substantially perpendicular to the axes, and a plurality of gearwheels that are rotationally fix or rotationally fixable to the shafts, the shafts comprising at least one output shaft and at least one countershaft, the shafts being suspended by bearings that are seated in the first and/or second bearing seats.

14. Method of manufacturing a multi-ratio gearbox housing for a vehicle, comprising:

providing a casting mould for housing that comprises a first bearing seat having a cylindrical inner surface;

arranging at least one reinforcement member within the mould, such that a first cylindrical inner surface of the reinforcement member surrounds the first bearing seat for reducing thermal radial expansion of the first bearing seat in the finished product;

casting light metal material into the mould, wherein the reinforcement member being of a material the coefficient of thermal expansion of which is less than the coefficient of thermal expansion of the light metal material of the housing, and wherein a radial distance between the first cylindrical inner surface of the reinforcement member and the cylindrical inner surface of the first bearing seat is constant along circumferential lines of the first bearing seat, facilitating improved form stability of the cylindrical inner surface of the first bearing seat over the temperature operating range of the housing.

15. Method according to claim 14, further comprising:

providing the housing with also a second bearing seat having a cylindrical inner surface, wherein a first axis of the first bearing seat being parallel with a second axis of the second bearing seat, wherein the reinforcement member having also a second cylindrical inner surface surrounding the second bearing seat for reducing thermal radial expansion of the second bearing seat, and for improving an interrelating dimensional stability of the first and second bearing seats, a radial distance between the second cylindrical inner surface and the cylindrical inner surface of the second bearing seat is constant along circumferential lines of the second bearing seat facilitating improved form stability of the cylindrical inner surface of the second bearing seat over the temperature operating range of the housing.