Frustoconically supported valve stem seal assembly

Patent metadata

Field	Value
Publication number	US-10513951-B2
Application number	US-201616061793-A
Country	US
Kind code	B2
Filing date	Dec 15, 2016
Priority date	Dec 15, 2015
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

A valve stem seal assembly has an elastomeric seal with first and second radially inwardly directed sealing lips that are in intimate sealing contact with a valve stem. The assembly also has a metal seal retainer with a first metal seal retainer portion that has a surface axially slanted inward and downward from a top of the elastomeric seal. This slanted portion forms a metal frustoconical foundation with a second metal seal retainer portion that directly radially extends from the metal frustoconical foundation. The axially slanted inward surface of the metal retainer is directly radially outward from the radially inwardly directed first sealing lip.

First claim

What is claimed is:

1. A valve stem seal assembly, comprises:
an elastomeric seal having first and second radially inwardly directed sealing lips in intimate sealing contact with a valve stem; and
a metal seal retainer having a first metal seal retainer portion with a surface axially slanted inward and downward from a top of the elastomeric seal to form a metal frustoconical foundation with a second metal seal retainer portion radially extending therefrom;
wherein the axially slanted inward surface of the metal retainer is radially outward from the radially inwardly directed first sealing lip of the elastomeric seal.

2. The valve stem seal assembly, of claim 1 , wherein the elastomeric seal has an axially inwardly slanted surface that is angled inward starting from an outer upper edge of the retainer to an inner groove G of the retainer, and then extends through a flat F area radially from the inner groove; and
wherein the axially inwardly slanted surface extends continuously circumferentially about the retainer, so that the frustoconical foundation isolates an upper portion of the elastomer seal that is above the lips from the lower portion of the elastomeric seal that is below the lips.

3. The valve stem seal assembly of claim 2 , wherein the metal seal retainer with said first metal seal retainer portion has an inward surface that is axially slanted inwardly from a top of the elastomeric seal; and
wherein the top of the retainer is flush with the top of the seal and the first metal seal retainer portion is downwardly slanted to unitarily form the metal frustoconical foundation with said second metal seal retainer portion that radially extends therefrom, so as to form the groove shape.

4. The valve stem seal assembly of claim 3 , wherein throughout the groove shaped inward retainer portion the seal/retainer surfaces stay in intimate sealing contact with each other, while the seal/retainer surfaces remain coplanar with each other.

5. The valve stem seal assembly of claim 4 , wherein the slanted surface of the metal retainer is radially outward from the inwardly directed first sealing lip of the elastomeric seal, the first metal seal retainer portion and the second inwardly directed sealing lip of the elastomeric seal are substantially directed inwardly at an angle θ from an axis A of the valve stem; and
wherein a lower portion of the elastomeric seal is in sealing contact and is coplanar with a lower portion of the metal seal retainer and that the metal frustoconical foundation blocks axial stress exerted on the seal from gas pressure in the engine port, so that the axial stress is kept from axially forcing the seal to move axially straight up and inline along the inside surfaces of the retainer, that the seal is prevented from extruding axially upward, and that the frustoconical foundation contains engine gasses of the second sealing lip.

6. The valve stem seal assembly of claim 5 , wherein the elastomeric seal surface and the retainer surface are in direct contact with each other while both are inwardly directed, so that the frustoconical shape of the foundation applies a resistive force FR to the first radially inwardly directed sealing lip and applies a back support force FB to the second radially inwardly directed sealing lip.

7. The valve stem seal assembly of claim 6 , wherein a passing of excess oil and debris between the first sealing lip and the valve stem are blocked by the metal frustoconical foundation; and
wherein a passing of gas under pressure between the second sealing lip and the valve stem is blocked by the second sealing lip in conjunction with the metal frustoconical foundation, so that oil metering rate is eliminated along with containment of engine gases in the axial direction by the metal frustoconical foundation without an extrusion of the elastomeric seal.

8. The valve stem seal assembly of claim 7 , wherein, at the second metal seal retainer portion, the inward surface of the retainer portion and the outward surface of the elastomeric seal are in direct axial contact with each other; and
wherein the surfaces of the first valve stem seal assembly block a passing of the gas under pressure between the second sealing lip and the stem.

9. The valve stem seal assembly of claim 8 , wherein the first lower radial retainer portion is radially adjoined to a radially bending outward portion that is then adjoined to a second lower radial retainer portion that is further adjoined to an axial spring seat flange; and
wherein a lower seal portion and the first lower vertical retainer portion have intimate respective sealing surfaces, so that the lower seal portion has ribs that make intimate sealing contact with a valve guide that has a valve spring therearound.

10. The valve stem seal assembly of claim 8 , further comprising a valve guide having a valve guide step and a lower vertical retainer portion that cylindrically extends to the bottom of a second valve stem seal assembly, so as to be applied to an engine arrangement with limited lateral space available.

11. The valve stem seal assembly of claim 8 , wherein the frustoconical retainer foundation comprises steel.

12. The valve stem seal assembly of claim 8 , wherein the angle θ is 35°.

Assignees

• Dana Automotive Systems Group

Inventors

• Hegemier Timothy A

Classifications

• F01L3/08 Primary

  Valves guides; Sealing of valve stem, e.g. sealing by lubricant · CPC title

• F01L1/26

  characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder (with coaxial valves F01L1/28) · CPC title

• F01L3/085

  Valve cages · CPC title