Boundary layer improvement of plate springs or undulating springs

• US 20080006351A1
• Filed: 06/22/2007
• Published: 01/10/2008
• Est. Priority Date: 06/23/2006
• Status: Active Grant

• Current Assignee: Muhr und Bender KG
• Original Assignee: Muhr und Bender KG
• Inventors: Roth, Sven, Buchner, Peter, Rinsdorf, Andreas, Hesselmann, Bernfried, Muhr, Thomas
• Granted Patent: US 9,003,850 B2
• Time in Patent Office: Days
• US Class Current: 148/559
• CPC Class Codes: B23P 9/02 Treating or finishing by applying pressure, e.g. knurling B23P9/04 takes precedence
• CPC Class Codes: B24C 1/10 for compacting surfaces, e.g. shot-peening for deforming sheet metal, tubes or profiles B21D31/06; as a metallurgical treatment C21D7/00, C22F1/00
• CPC Class Codes: C21D 1/78 Combined heat-treatments not provided for above
• CPC Class Codes: C21D 7/06 by shot-peening or the like
• CPC Class Codes: C21D 9/02 for springs
• CPC Class Codes: F16F 1/32 Belleville-type springs friction-clutch diaphragm springs F16D13/583
• CPC Class Codes: F16F 2226/02 Surface treatments

Abstract

A process for producing plate springs or undulating springs wherein surface regions which are subjected to tensile stresses when the spring is under load are provided with an internal compressive stress in the boundary layer, wherein said surface regions are rollingly compressed by a ball or roller or subjected to tensile stress and compressed by shot peening.

Claims

1. A process of producing plate springs or undulating springs wherein surface regions which are subjected to tensile stresses when the spring is under load are provided with an internal compressive stress in the boundary layer, wherein said surface regions are rollingly compressed by a ball or roller.

2. A process according to claim 1, wherein

said layer regions are rollingly compressed in circular movements of the ball or roller around the axis of the spring, relative to the spring.

3. A process according to claim 1, wherein

said surface regions are rollingly compressed while tensile stresses are forced on to said surface regions.

4. A process according to claim 1, wherein

the rolling compression takes place at an increased temperature of the spring of at least 180°

.

5. A process according to claim 1, wherein

the rolling compression follows an earlier compression process by shot peening.

6. A process according to claim 5, wherein

the total surface of the spring is compressed by shot peening and that partial surfaces of the spring are compressed by rolling compression.

11. A process according to claim 3, wherein

said surface regions are compressed rollingly or by shot peening, with the spring being at least elastically deformed, more particularly pressed into a flat condition.

12. A process according to claim 1, wherein

said rolling compression takes place after the spring has been quenched and tempered.

7. A process of producing a plate spring or undulating spring wherein surface regions which are subjected to tensile stresses when the spring is under load are provided with an internal compressive stress in the boundary layer, wherein said surface regions are subjected to a tensile stress and compressed by shot peening, at least when the spring is in an elastically deformed state.

8. A process according to claim 7, wherein

the yield stress is exceeded in said surface regions while the latter are compressed by shot peening.

9. A process according to claim 7, wherein compression by shot peening takes place at an increased temperature of the spring ranging between 150°

and 250°

.

10. A process according to claim 7, wherein

the total surface of the spring is compressed by shot peening and that partial surfaces of the spring are compressed by shot peening, with the spring being in a deformed condition.

13. A plate spring or undulating spring wherein surface regions which are subjected to tensile stresses when the spring is under load are provided with an internal compressive stress in the boundary layer, wherein

the maximum of the internal compressive stress in the boundary layer of rollingly compressed surface regions amounts to at least 850 MPa.

14. A spring according to claim 13, wherein

the internal compressive stress in the surface layer of the rollingly compressed surface regions in a depth of 200 μ

m amounts to at least 500 MPa, more particularly at least 700 MPa, preferably at least 1000 MPa.

17. A spring according to claim 13, wherein

at least one of the inner or outer annular edges is provided with an internal compressive stress in the boundary layer, which internal compressive stress is generated by a rolling compression or compression by shot peening, more particularly with the spring being in the deformed condition.

18. A plate spring according to claim 13, wherein

at least one boundary region of the internally conical underside is provided with an internal compressive stress in the boundary layer, which internal compressive stress is generated by a rolling compression or compression by shot peening, more particularly with the spring being in the deformed condition.

19. An undulating spring according to claim 13, wherein

at least one boundary region of the undulating upper and lower surfaces are provided with an internal compressive stress in the boundary layer, which internal compressive stress is generated by a rolling compression or compression by shot peening, more particularly with the spring being in the deformed condition.

20. A plate spring according to claim 13, wherein

the plate spring is slotted at its inner edge.

21. A plate spring according to claim 13, wherein

the plate spring is slotted at its outer edge.

22. A plate spring according to claim 13, wherein

the plate spring is toothed at its inner edge.

23. A plate spring according to claim 13, wherein

the plate spring is toothed at its outer edge.

15. A plate spring or undulating spring wherein surface regions which are subjected to tensile stresses when under load are subjected to an internal compressive stress in the boundary layer, wherein

the maximum of the internal compressive stress in the boundary layer of surface regions treated by shot peening with the spring being in the deformed condition amounts to at least 850 MPa.

16. A spring according to claim 15, wherein

the internal compressive stress in the surface boundary of the surface regions compressed by shot peening with the spring being in the deformed condition in a depth of 100 μ

m amounts to at least 850 MPa, more particularly at least 850 MPa.