Method of producing oil seal

• US 4,723,350 A
• Filed: 07/15/1986
• Issued: 02/09/1988
• Est. Priority Date: 02/15/1986
• Status: Expired due to Term

• Current Assignee: NOK Corporation
• Original Assignee: NOK Corporation
• Inventors: Hoshi, Torami, Kobayashi, Nobuyuki
• Primary Examiner(s): Lowe, James
• Application Number:
  US06/885,653
• Time in Patent Office: 574 Days
• Field of Search: 264/138, 264/163, 264/266, 264/268, 264/159, 264/293, 264/296, 264/318, 264/310, 264/292, 264/339, 264/320, 425/DIG. 47, 29/527.1, 29/469.5, 29/557, 29/417, 29/511, 29/520, 277/1, 277/134, 277/152, 277/153
• US Class Current: 29/417
• CPC Class Codes: B23P 15/00 Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
• CPC Class Codes: B29C 67/00 Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
• CPC Class Codes: B29C 67/0014 for shaping tubes or blown tubular films
• CPC Class Codes: B29D 1/00 Producing articles with screw-threads
• CPC Class Codes: B29D 99/0053 Producing sealings B29D99/0085 takes precedence
• CPC Class Codes: B29L 2031/26 Sealing devices, e.g. packaging for pistons or pipe joints
• CPC Class Codes: F16J 15/3244 with hydrodynamic pumping action
• CPC Class Codes: F16J 15/328 Manufacturing methods specially adapted for elastic sealings moulding B29C
• CPC Class Codes: Y10S 277/924 Deformation, material removal, or molding for manufacture of seal
• CPC Class Codes: Y10S 425/047 Seal ring
• CPC Class Codes: Y10T 29/49798 Dividing sequentially from leading end, e.g., by cutting or breaking
• CPC Class Codes: Y10T 29/49918 At cup or tube end
• CPC Class Codes: Y10T 29/49934 by axially applying force

Abstract

A method of producing an oil seal comprises the following steps: a slicing step in which a seal ring is sliced from an end of a tubular billet of a resin material in a predetermined axial thickness; a fixing step in which the radially outer portion of the seal ring is fixed in the support member; and a bending-out/thread-forming step in which the radially inner portion of the seal ring is bent out of the plane of the radially outer portion of the seal ring thereby forming a tubular seal lip, and sequentially after forming of this seal lip, a screw thread is formed on the inner peripheral surface of the tubular seal lip. The fixing step is conducted by a press having an upper die and a lower die, in which the seal ring is fixed in the support member. The bending-out/thread-forming step is conducted by the press in which the radially inner portion of the seal ring is deformed into the tubular seal lip, and a screw thread is formed on the inner peripheral surface of the tubular seal lip by means of a mandrel having a tap. The bending-out/thread-forming step may be conducted in advance of the fixing step.

Claims

1. A method of producing an oil seal comprising:

slicing an annular seal ring having a predetermined axial thickness from an end of a tubular billet of a resin material;

providing a substantially annular seal ring support member having an axial end portion;

placing said seal ring in said support member;

placing said seal ring and support member in a press;

fixing said seal ring in said support member by curling the axial end portion of the support member radially inwardly;

bending the radially inner portion of said seal ring out of the plane of the radially outer portion of said seal ring by driving a mandrel coaxially through said radially inner portion of said seal ring thereby forming a tubular seal lip on said seal ring;

providing a screw thread cutting-tap on said mandrel; and

cutting a screw thread on the inner peripheral surface of said tubular seal lip by rotating said tap into said tubular seal lip.

2. A method as claimed in claim 1 wherein:

said resin material is selected from the group consisting of PTFE FEP, PFA, EPFE, polyetheretherketone and polymeric polyethylene.

3. A method as claimed in claim 2 and further comprising:

providing a filler in said resin material which improves the wear resistance and the friction characteristic of said resin material.

4. A method as claimed in claim 3, wherein:

said filler comprises at least one material selected from the group consisting of short glass fibers, short carbon fibers, metal fibers, short ceramics fibers, graphite powder, metal powder, glass powder, ceramics powder, and resin powder.

5. A method as claimed in claim 1 wherein:

said fixing of said seal ring to said support member is produced by said press.

6. A method as claimed in claim 1 wherein:

said curling comprises roller curling.

7. A method as claimed in claim 1 wherein said press includes an upper die and a lower die and further comprising:

providing a dust lip on the radially inner portion of said support member; and

interposing an annular wall member on the upper die between said dust lip and the mandrel during said tubular seal lip-forming step and said screw thread-cutting step for preventing the mandrel from contacting said dust lip.

8. A method as claimed in claim 1 wherein the press includes an upper die, a lower die, an inner peripheral surface on the lower die and a rounded portion at the upper end of the inner peripheral surface adjacent the upper die, and further comprising:

placing said seal ring between the upper and lower dies;

bending said seal ring over said rounded portion during said tubular seal lip-forming step; and

holding said seal ring on said rounded portion during said screw thread-cutting step.

9. A method as claimed in claim 1 and further comprising:

placing a sleeve on the mandrel before said tubular seal lip-forming step; and

driving said sleeve into engagement with said tubular seal lip during further movement of the mandrel after said screw thread-cutting step.

10. A method of producing an oil seal comprising sequentially:

slicing an annular seal ring having a predetermined axial thickness from an end of a tubular billet of a resin material

providing a substantially annular seal ring support member having an axial end portion;

placing said seal ring in said support member;

placing said seal ring and support member in a press;

bending the radially inner portion of said seal ring out of the plane of the radially outer portion of said seal ring by driving a mandrel coaxially through said radially inner portion of said seal ring thereby forming a tubular seal lip on said seal ring;

providing a screw thread cutting-tap on said mandrel;

cutting a screw thread on the inner peripheral surface of said tubular seal lip by rotating said tap into said tubular seal lip; and

fixing said seal ring in said support member by curling the axial end portion of the support member radially inwardly.

11. A method of producing an oil seal as claimed in claim 10 wherein:

said resin material is selected from the group consisting of PTFE, polyetheretherketone and polymeric polyethylene.

12. A method as claimed in claim 11 and further comprising:

providing a filler in said resin material which improves the wear resistance and the friction characteristic of said resin material.

13. A method as claimed in claim 12 wherein:

said filler comprises at least one material selected from the group consisting of short glass fibers, short carbon fibers, metal fibers, short ceramics fibers, graphite powder, metal powder, glass powder, ceramics powder, and resin powder.

14. A method as claimed in claim 10 wherein:

said fixing of said seal ring to said support member is produced by said press.

15. A method as claimed in claim 10 wherein:

said curling comprises roller curling.

16. A method as claimed in claim 10 wherein the press includes an upper die, a lower die, an inner peripheral surface on the lower die and a rounded portion at the upper end of the inner peripheral surface adjacent the upper die, and further comprising:

placing said seal ring between the upper and lower dies;

bending said seal ring over said rounded portion during said tubular seal lip-forming step; and

holding said seal ring on said rounded portion during said screw thread-cutting step.

17. A method as claimed in claim 10 and further comprising:

placing a sleeve on the mandrel before said tubular seal lip-forming step; and

driving said sleeve into engagement with said tubular seal lip during further movement of the mandrel after said screw thread-cutting step.

18. A method as claimed in claim 10 wherein said press includes an upper die and a lower die and further comprising:

providing a dust lip on the radially inner portion of said support member; and

interposing an annular wall member on the upper die between said dust lip and the mandrel during said tubular seal lip-forming step and said screw thread-cutting step for preventing the mandrel from contacting said dust lip.