Patent Application
20210025295
The invention pertains to the field of vane seals. More particularly, the invention pertains to a two-piece vane seal for a phaser of a variable cam timing system.
Internal combustion engines have employed various mechanisms to vary the relative timing between the camshaft and the crankshaft for improved engine performance or reduced emissions. The majority of these variable camshaft timing (VCT) devices use one or more “vane phasers” on the engine camshaft (or camshafts, in a multiple-camshaft engine). Vane phasers have a rotor assembly with one or more vanes, mounted to the end of the camshaft, coaxially located within a housing assembly. The rotor assembly has at least one vane separating a chamber formed between the housing assembly and the rotor assembly into an advance chamber and a retard chamber. The vane is capable of rotation to shift the relative angular position of the housing assembly and the rotor assembly. A vane seal is received within the end of at least one of the vanes. The vane seal provides a seal between the advance and retard chambers on either side of the vane, such that when fluid pressure is applied to either of the advance or retard chambers and the vane rotates, the seal prevents leakage across the chambers. A conventional vane seal is typically one piece and made of molded plastic with a fixed geometry. Wear and thermal expansion can cause changes to the fixed geometry of the conventional vane seal.
A two piece vane seal reduces leakage across the vane seal. The vane seal having a first portion and a second portion, the second portion being a mirror image of the first portion. The first portion and the second portion each have a first end, a second end connected to the first end, and a flange extending axially from the first end. The first end and the second end are connected by a longitudinally extending wall, whereas the longitudinally extending wall includes an inner surface, a rectangular structure extending radially outward from and parallel to the inner surface of the longitudinally extending wall, a flat surface extending parallel to and radially outward from the inner surface of the longitudinally extending wall. A first longitudinal recess defined by the rectangular structure adjacent to at least the flat surface defining a second longitudinal recess between the flat surface and the rectangular structure and including a radially outward exposed surface and at least one spring end retainer extending radially outward from the inner surface of the longitudinally extending wall. An edge protruding radially outward from the inner surface of the longitudinally extending wall projecting from the second end a length and aligned with the second longitudinal recess including a first end with a protrusion and a second end. A curved ledge extending radially outward from and parallel to the inner surface of the longitudinally extending wall between the second end and the spring end retainer. A ramp extending radially outward from and parallel to the inner surface of the longitudinally extending wall connecting the curved ledge to the flat surface. The first portion assembled relative to and connected to the second portion with the inner surface of the longitudinally extending wall of the first portion opposite the inner surface of the longitudinally extending wall of the second portion, such that the second longitudinal recess of the second portion receives the edge extending from the longitudinally extending wall of the first portion. A spring comprising a first end, a second end, and a length, the first end received by the spring end retainer on the inner surface of the longitudinally extending wall of the second portion, the second end received by the spring end retainer on the inner surface of the longitudinally extending wall of the first portion
In another embodiment, a two piece vane seal has a first portion having a first end, a second end connected to the first end, and a flange extending axially from the first end. Whereas the first end and the second end are connected by a first longitudinally extending wall including an inner surface with a rectangular structure extending radially outward from and parallel to the inner surface of the first longitudinally extending wall defining a first longitudinal recess, the rectangular structure being adjacent to at least a flat surface defining a second longitudinal recess between the flat surface and the rectangular surface and having a radially outward exposed surface. At least one spring end retainer extending radially outward from the inner surface of the first longitudinally extending wall and an edge extending radially outward from the inner surface of the first longitudinally extending wall protruding from the second end a length and aligned with the second longitudinal recess. A second portion including a first end, a second end connected to the first end, and a flange extending axially from the first end. Whereas the first end and the second end are connected by a second longitudinally extending wall having an inner surface with a rectangular structure extending radially outward from and parallel to the inner surface of the second longitudinally extending wall defining a first longitudinal recess, the rectangular structure being adjacent to at least a flat surface defining a second longitudinal recess of the second longitudinally extending wall between the flat surface and the rectangular surface and having a radially outward exposed surface. At least one spring end retainer extending radially outward from the inner surface of the second longitudinally extending wall. An edge extending radially outward from the inner surface of the second longitudinally extending wall protruding from the second end a length and aligned with the second longitudinal recess of the second longitudinally extending wall. The first portion is assembled relative to and connected to the second portion with the inner surface of the first longitudinal wall opposite the inner surface of the second longitudinal wall, such that the second longitudinal recess of the second longitudinally extending wall receives the edge extending from the first longitudinally extending wall and the second longitudinal recess of the first longitudinally extending wall receives the edge extending from the second longitudinally extending wall. A spring having a first end, a second end, and a length, the first end received by the spring end retainer on the inner surface of the second longitudinally extending wall of the second portion, the second end received by the spring end retainer on the inner surface of the first longitudinally extending wall of the first portion.
In yet another embodiment, a variable cam timing phaser for an internal combustion engine having a housing assembly, a rotor assembly coaxially located within the housing assembly having vanes extending therefrom, the end of the vane defining a groove. A vane seal received within the groove, the vane seal having a first portion having a first end, a second end, and a flange extending axially from the first end. Whereas the first end and the second end are connected by a first longitudinally extending wall including an inner surface with a rectangular structure extending radially outward therefrom and parallel to the inner surface of the first longitudinally extending wall defining a first longitudinal recess. The rectangular structure being adjacent to at least a flat surface defining a second longitudinal recess between the flat surface and the rectangular surface and having a radially outward exposed surface. At least one spring end retainer extending radially outward from the inner surface of the first longitudinally extending wall. An edge extending radially outward from the inner surface of the first longitudinally extending wall extending from the second end a length and aligned with the second longitudinal recess. A second portion including a first end, a second end attached to the first end, and a flange extending axially from the first end. Whereas the first end and the second end are connected by a second longitudinally extending wall having an inner surface with a rectangular structure extending radially outward from and parallel to the inner surface of the second longitudinally extending wall defining a first longitudinal recess. The rectangular structure being adjacent to at least a flat surface defining a second longitudinal recess of the second longitudinally extending wall between the flat surface and the rectangular surface and having a radially outward exposed surface. At least one spring end retainer extending radially outward from the inner surface of the second longitudinally extending wall. An edge extending radially outward from the inner surface of the second longitudinally extending wall extending from the second end a length and aligned with the second longitudinal recess of the second longitudinally extending wall. The first portion is assembled relative to and connected to the second portion with the inner surface of the first longitudinal wall opposite the inner surface of the second longitudinal wall, such that the second longitudinal recess of the second longitudinally extending wall receives the edge extending from the first longitudinally extending wall. The second longitudinal recess of the first longitudinally extending wall receives the edge extending from the second longitudinally extending wall. A spring having a first end, a second end, and a length, the first end received by the spring end retainer on the inner surface of the second longitudinally extending wall of the second portion, the second end received by the spring end retainer on the inner surface of the first longitudinally extending wall of the first portion.
A two piece vane seal 100 includes a first portion 10a and a second portion 10b. The second portion 10b may be smaller, larger, or a mirror image of the first portion 10a. Therefore, the first portion 10a and the second portion 10b may have identical, or differing, surfaces and recesses described in further detail below. When the first portion 10a is assembled relative to the second portion 10b, with like surfaces interfacing relative to each other, the two piece vane seal 100 forms a complete vane seal enclosing and sealing a spring 50, such as leaf spring, such that the two piece vane seal 100 can be placed within an end of the vane 104 of a rotor assembly 105 as shown in
Referring to
The first end 90 and the second end 91 are connected through a longitudinally extending side wall 60a, 60b. The longitudinally extending side wall 60a, 60b has an outer surface 61 which will be adjacent the vane 104 of the rotor assembly 105 when installed and an inner surface 62. The first end 90 of each portion 10a, 10b of the two piece vane seal 100 has a flange 12a, 12b perpendicular to the side wall 60a, 60b. The flange 12a, 12b contains a bore 25a, 25b which receives a protrusion 22a, 22b discussed in further detail below. Ends of the flange 12a, 12b have an interlock protrusion 13a, 13b which is received within an opening 25a, 25b present within the opposing portion of the flange 12a, 12b of the vane seal as shown in
The second end 91 has an end wall 16a, 16b, perpendicular to the flanges 12a, 12b extending transversely opposite the flange 12a, and 12b. Between the end wall 16a, 16b and the flange 12a, 12b with the interlocking protrusion 13a, 13b is a flat surface 17a, 17b adjacent the inner surface 62 of the longitudinally extending side wall 60a, 60b. The flat surface 17a, 17b extends from the flange 12a, 12b to a ramp 18a, 18b, with the ramp 18a, 18b terminating in a curved ledge 20a, and 20b.
Adjacent the flat surface 17a, 17b and below the curved ledge 20a, 20b is another flat surface 88a, 88b with a side edge 24b and an exposed edge 29b.
Below the flat surfaces 17a, 17b, 88a, 88b is a rectangular structure 85a, 85b with a longitudinal recess 21a, 21b which is spaced a distance to form another longitudinal recess 19a, 19b between the flat surfaces 17a, 17b and the rectangular structure 85a, 85b. The rectangular structure has a side surface 86a, 86b and an exposed surface 30a, 30b and forms the bottom 70a, 70b of the two piece vane seal 100. The bottom 70a, 70b is preferably contoured.
Along the inner surface 62 of the side walls 60a, 60b aligned with the longitudinal recess 19a, 19b is an angular surface 89a, 89b with an edge 23a, 23b which terminates just prior to the end of the side wall 60a, 60b in a protrusion 22a, 22b perpendicular to the end walls 16a, 16b.
When the first portion 10a and the second portion 10b are mated together by sliding the first portion 10a and second portions 10b relative to each other, with surface 87b of the angular surface 89b is placed adjacent surface 87a of the angular surface 89a, such that ramps 20a and 20b are adjacent, with ramp 20a being on top of surface 88b and ramp 20b being on top of surface 88a, such that exposed surfaces 29a and 29b of the flat surface 88a, 88b are adjacent. Additionally, protrusion 22b is received within recess 19a and protrusion 22a is received within recess 19b to lock the first portion 10a relative to the second portion 10b. Exposed surface 30a is also adjacent exposed surface 30b.
Extending perpendicular from the inner surface 62 of the longitudinally extending side wall 60a, 60b and above the flat surface 17a, 17b is a spring end retainer 14a, 14b. When the first portion 10a and the second portion 10b are mated to form the two piece vane seal 100, the spring end retainer 14a, 14b extends from the inner surface 62 of the longitudinally extending side wall 60a of a first portion 10a to the inner surface 62 of the longitudinally extending side wall 60b of the second portion 10b forming three partitions or recesses. A first end recess 200 is formed by the flange 12a of the first portion 10a, the flat surface 17a of the first portion 10a, the spring end retainer 14a of the first portion 10a, the inner surface 62 of the longitudinally extending wall 60a of the first portion 10a and the inner surface 62 of the longitudinally extending wall 60b of the second portion 10b. A second end recess 201 an end opposite the first recess 200 is formed by the flange 12b of the second portion 10b, the flat surface 17b of the second portion 10b, the spring end retaining 14b of the second portion 10b, the inner surface 62 of the longitudinally extending wall 60a of the first portion 10a and the inner surface 62 of the longitudinally extending wall 60b of the second portion 10b. A medial recess 203 between the first end recess 200 and the second end recess 201 is formed by spring end retainer 14a, spring end retainer 14b, flat surface 17a, 17b, and ramp 18a, 18b and curved protrusions 20a, 20b. A spring 50, preferably a leaf spring is received within the recesses of the two piece vane seal 100. In another embodiment, spring 50 is capable of being an accordion spring, a blade spring, or a compression spring. The spring 50 is an elongated rectangle with curled ends. In a free unanchored state, the spring 50 curls. When the spring 50 is installed into the vane seal 100, the spring 50 is in an uncurled state. The spring 50 has a first curled end 50a, a second curled end 50b with a length 50c between the first curled end 50a and the second curled end 50b. A first curled end 50a of the spring 50 is received within the first recess 200 and abuts the spring end retainer 14a. A second curled end 50b of the spring 50 is received with the second recess 201 and abuts the spring end retainer 14b. The length 50c of the spring 50 is received within the medial recess 203 between the spring end retainers 14a, 14b. The first end 50a of the spring 50, and second end 50b of the spring 50 are preferably rounded to allow for easy rotation within the recesses although other geometries may also be used. Spring 50 provides radial and axial force on each portion 10a, 10b of the two piece vane seal 100 to preload the vane seal 100 against the sliding sealing surfaces of the rotor assembly as shown in
In
After the two piece vane seal 100 is installed within the end of the vane 104, a first seal land 220a is preferably formed between the contoured surfaces of bottom surfaces 70a, 70b and the housing assembly 101, and around the perimeter of the two piece vane seal 100, a second seal land 220b is formed between an edge of the flange 12a, 12b and the vane 104, and a third seal land 220c is formed between an edge of the flange 12a, 12b which connects to the bottom 70a, 70b and the end plates of the housing assembly 101. The seal coefficient of friction will be altered based upon qualitative differences in the materials, surface finishes, and fluids used for the vane seal 100 and in the rotor assembly 105.
As shown in
In one embodiment, the rotor assembly 105 and two piece vane seal 100 slide to one side allowing a clearance of 0.030 mm from the rotor assembly 105 to the inner plate of the housing assembly 101, enabling oil or hydraulic fluid to flow in the path of least resistance and to move around the seal 100 between the rotor assembly and inner plate of the housing assembly 101.
The two piece vane seal 100 can extend or retract to conform to geometric irregularities. Each half or portion, 10a, 10b is free to individually move axially to decrease close axial clearances and provide lower leakage past the seal and conform to geometric irregularities resulting from manufacturing tolerance.
While vane seal spring 50 is only shown being attached to retaining shoulders 31a and 31b, vane seal spring 50 is capable of being molded into one half, first vane seal component 10a and second vane seal component 10b, of the two piece vane seal 100 to simplify assembly.
The two piece vane seal 100 is preferably formed of a single material such as metal. Two piece vane seal 100 can expand and contract to compensate for the differing thermal expansion. Two piece vane seal 100 is capable of compensating for component wear and extending the compensation to vane seal performance.
Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.
