Patent Application
20180142584
The present disclosure relates to a particulate trap for a camshaft phaser, in particular, a particulate trap including a magnet arranged to attract and capture magnetic particulate.
As is known in the art, fluid 220 flows into and out of chambers 206 to establish a rotational position of rotor 204 with respect to stator 202. For example, when fluid pressure in space 212 is greater than fluid pressure in chambers 206: fluid 220 displaces flaps 224 of plate 218 (covering channels 214) in axial direction AD1; and fluid 220 flows through channels 214 along path 222 into chambers 206. For example, when fluid pressure in space 212 is less than fluid pressure in chambers 206, fluid 220 in chambers 206 displaces flaps 224 in axial direction AD2 to block fluid flow out of chambers 206 and into space 212 through channels 214.
Fluid 220 typically becomes contaminated by magnetic and non-magnetic particulate generated by operation of the engine. In general, contamination degrades the phasing function of phaser 200. For example, the contaminant can interfere with operation of the check valve plate (for example preventing flaps 224 from properly opening or blocking channels 214). Interfering with operation of the check valve plate degrades operation of phaser 200, for example by preventing proper operation of the engine timing operations dependent upon the proper transport of fluid into and out of chambers 206.
According to aspects illustrated herein, there is provided a camshaft phaser, including: an axis of rotation; a stator with a radially outer surface including a plurality of teeth; a rotor located radially inwardly of the stator; a chamber bounded at least in part by the stator and the rotor; a locking cover; a spring cover non-rotatably connected to the locking cover; a space enclosed, at least in part, by the spring cover and the locking cover; a plurality of fasteners non-rotatably connecting the stator and the locking cover; a spiral spring located in the space and including a first end fixed to the stator; and a magnetic trap located within the space and including a magnet.
According to aspects illustrated herein, there is provided a camshaft phaser, including: an axis of rotation; a stator with a radially outer surface including a plurality of teeth; a rotor; a locking cover; a spring cover including a radially outer side directly connected to the locking cover; a space enclosed by the locking cover and the spring cover; a spiral spring located in the space and including a first end fixed with respect to the stator; and a magnetic trap including a portion of the space and a magnet having a radially outwardly facing side, the magnet located within the portion of the space and radially between the spiral spring and the radially outer side of the spring cover. The portion of the space is enclosed, at least in part, by the locking cover, the spring cover and the magnet. The magnetic trap includes a plurality of magnetic field lines generated by the magnet, the plurality of magnetic field lines: passing radially inwardly through the portion of the space; and passing radially inwardly through the radially outwardly facing side of the magnet.
According to aspects illustrated herein, there is provided a method of operating a camshaft phaser including a stator, a rotor, a chamber bounded at least in part by the stator and the rotor, a spring cover having a radially outer wall directly connected to a locking cover, a space enclosed by the spring cover and the locking cover, a spiral spring located in the space, and a magnet located in the space, the method including: generating, with the magnet, magnetic field lines; and passing the magnetic field lines through the space.
Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which:
At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the disclosure. It is to be understood that the disclosure as claimed is not limited to the disclosed aspects.
Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present disclosure.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure.
To clarify the spatial terminology, objects 12, 13, and 14 are used. As an example, an axial surface, such as surface 15A of object 12, is formed by a plane co-planar with axis 11. However, any planar surface parallel to axis 11 is an axial surface. For example, surface 15B, parallel to axis 11, but off-set from surface 15A in direction RD1, also is an axial surface. An axial edge is formed by an edge, such as edge 15C, parallel to axis 11. A radial surface, such as surface 16A of object 13, is formed by a plane orthogonal to axis 11 and co-linear with a radius, for example, radius 17A. A radial edge is co-linear with a radius of axis 11. For example, edge 16B is co-linear with radius 17B. Surface 18 of object 14 forms a circumferential, or cylindrical, surface. For example, surface 18 forms radially outer circumference 19 of object 14. Radially outer circumference 19 is defined by radius 20.
Axial movement is in direction axial direction AD1 or AD2. Radial movement is in radial direction RD1 or RD2. Circumferential, or rotational, movement is in circumferential direction CD1 or CD2. The adverbs “axially,” “radially,” and “circumferentially” refer to movement or orientation parallel to axis 11, orthogonal to axis 11, and about axis 11, respectively. For example, an axially disposed surface or edge extends in direction AD1, a radially disposed surface or edge extends in direction RD1, and a circumferentially disposed surface or edge extends in direction CD1.
In an example embodiment, magnetic trap 102 includes retaining pin 128 fixedly connecting magnet 124 to locking cover 114. In an example embodiment, portion 126 is bounded, in part, by retaining pin 128. In an example embodiment, portion 126 is wholly bounded by locking cover 114, spring cover 116, magnet 124 and retaining pin 128. For example: cover 116 is sealed against cover 114 and sides 128A and 128B of pin 128; pin 128 is sealed against magnet 124; and magnet 124 is sealed against cover 114. Portion 126 includes opening 130 In an example embodiment, opening 130 connects portion 126 to remainder 132 of space 118. By “remainder of space 118” we mean the part of space 118 not including portion 126. In an example embodiment, opening 130 is bounded by locking cover 114, spring cover 116, magnet 124 and retaining pin 128. In an example embodiment, opening 130 faces in circumferential direction CD1. In an example embodiment, portion 126 is blocked off from remainder 132 in circumferential direction CD2, for example by wall 128C of pin 128.
In an example embodiment, portion 126 is bounded: radially inwardly by side 134A of magnet 124; radially outwardly by radially outermost wall 116A of spring cover 116; and axially by spring cover 116 and locking plate 114. In an example embodiment, line L2, orthogonal to axis of rotation AR, is co-linear with side 138.
Although magnetic trap 102 is shown configured with opening 130 facing in direction CD1, it should be understood that opening 130 can be configured with opening 130 facing in direction CD2, for example in instances in which phaser 100 rotates in direction CD2. In an example embodiment, magnet 124 is separated, in radial direction RD, orthogonal to axis of rotation AR, from spiral spring 122 by portion 140 of space 118.
The following should be viewed in light of
In an example embodiment, a third step passes the magnetic field lines radially inwardly through a side of the magnet facing, at least in part, radially outwardly (for example side 134A). In an example embodiment, passing the magnetic field lines through the space includes passing the magnetic field lines radially inwardly through a portion of the space bounded radially inwardly by a radially outwardly facing side of the magnet and bounded radially outwardly by the spring cover (for example portion 126) and a fourth step passes the magnetic field lines radially inwardly through the radially outwardly facing side of the magnet.
In an example embodiment: a fifth step passes the plurality of magnetic field lines through fluid located in the space (for example fluid F); a sixth step adheres magnetic particulate P, suspended in fluid F, to the magnet; and a seventh step completes a magnetic circuit, including the plurality of magnetic field lines, with a return flux path through the spring cover. In the discussion that follows, Px, with ‘x’ being a digit, is used to designate an example magnetic particulate P.
In an example embodiment, passing the plurality of magnetic field lines through fluid located in the space includes passing the plurality of magnetic field lines through fluid located in a portion of the space (for example portion 126) bounded radially inwardly by a radially outwardly facing side of the magnet (for example side 134A) and bounded radially outwardly by the spring cover (for example by wall 116A), and adhering magnetic particulate, suspended in the fluid, to the magnet includes adhering the magnetic particulate to the radially outwardly facing side of the magnet (for example particulate P1).
Non-magnetic particulate NP also can be suspended in fluid F. In the discussion that follows, NPx, with ‘x’ being a digit, is used to designate an example magnetic particulate NP. In an example embodiment: an eighth step rotates the camshaft phaser in a first circumferential direction (for example direction CD1); a ninth step displace, radially outwardly, non-magnetic particulate NP1 suspended in fluid F and located outside of the portion of the space; a tenth step displaces, in a second circumferential direction opposite the first circumferential direction (for example, direction CD2), the non-magnetic particulate into the portion of the space (for example, non-magnetic particulate NP2 in space 126); and an eleventh step blocks displacement, in the second circumferential direction, of the non-magnetic particulate out of the portion of the space (for example, non-magnetic particulate NP3 in contact with pin wall 128C).
The following discussion assumes that phaser 100 rotates in direction CD1 during operation; however, it should be understood that for operation of phaser 100 in direction CD2, the circumferential configuration of trap 102 is reversed and directions CD1 and CD2 are reversed in the following discussion. Advantageously, magnetic trap 102 and a method utilizing trap 102 address the problem noted above with respect to contaminant in fluid F in phaser 100. For example, during operation of phaser 100 in direction CD1: centrifugal force CF displaces magnetic and non-magnetic particulate (for example, non-magnetic particulate NP1 and magnetic particulate P2) radially outwardly toward side 116A and in circumferential alignment with space 126; and momentum force MF of phaser 100, generated by the rotation of phaser 100, displaces both magnetic and non-magnetic particulate through opening 130 and into space 126 (for example, non-magnetic particulate NP2 and magnetic particulate P3). Momentum force MF hinders or prevents magnetic and non-magnetic particulate from exiting space 126 through opening 130 in direction CD1.
Once magnetic particulate is in space 126, magnet 124 attracts magnetic particulate and the magnetic particulate adheres to magnet 124, for example as shown by magnetic particulate P1. Hence, magnetic particulate is taken out of the fluid circuit of phaser 100 and cannot interfere with the operation of phaser 100. For non-magnetic particulate, wall 128C of pin 128 blocks movement of non-magnetic particulate, such as particulate NP3, out of space 126 in direction CD2 and momentum force MF prevents movement of non-magnetic particulate out of space 126 in direction CD1. Hence, non-magnetic particulate is taken out of the fluid circuit of phaser 100 and cannot interfere with the operation of phaser 100.
When phaser 100 ceases to rotate, gravitation force displaces fluid F downward, typically draining at least a portion of fluid F out of portion 126. As the fluid drains, magnetic particulate adhering to magnet 124 remains adhered to magnet 124 and typically at least a portion of the non-magnetic particulate in portion 126 remains in portion 126. Then, when phaser 100 rotates again, additional particulate in fluid F is displaced into portion 126 for capture in portion 126.
It should be understood that magnet 124 is not limited to the shapes and configurations shown and that other shapes and configuration are possible. It should be understood that trap 102 is not limited to the orientation of field lines 136 shown in the figures. For example in an example embodiment (not shown), magnetic field lines pass radially inwardly through a circumferentially facing side of magnet 124, such side 138 or through a radially inwardly facing side of magnet 124, such as side 134B. Magnet 124 can be made of any material known in the art, including, but not limited to, molded powder metal, polymeric material, and elastomeric material.
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
