Check valve plate positioner for camshaft phaser

A camshaft phaser, including: an axis of rotation; a stator including a radially outermost surface with a plurality of teeth; a locking plate including a first side facing in a first axial direction, a bore in the first side, and a through-bore; a check valve plate axially located between the locking plate and the stator and including a through-bore and a displaceable valve flap aligned, in the first axial direction, with the through-bore for the locking plate; and a bushing disposed in the bore in the first side and in the through-bore for the check valve plate. The bushing extends past the locking plate in the first axial direction.

TECHNICAL FIELD

The present disclosure relates to a camshaft phaser, in particular a camshaft phaser with a bushing arranged to hold a check valve plate in position with respect to a locking plate.

BACKGROUND

FIG. 12is a partial cross-sectional view of prior art camshaft phaser200.FIG. 13is a partial perspective view of a portion of the locking plate, check valve plate and bushing inFIG. 12. Camshaft phaser200includes: stator202with teeth204; rotor206; locking plate208; check valve plate210; bushing212; and swing cover214. Timing chamber216is bounded, at least in part, by stator202, rotor206and check valve plate210. Space218is bounded, at least in part, by locking plate208and spring cover214.

For fluid pressure in space218greater than fluid pressure in chamber216, fluid in space218is arranged to displace flap220of plate210in axial direction AD1so that through-bore222in plate208, which is open to space218, is open to chamber216. Thus, fluid from space218flows to chamber216through through-bore222. For fluid pressure in chamber216greater than fluid pressure in space218, fluid in chamber216is arranged to displace flap220in axial direction AD2, opposite direction AD1, so that through-bore222is blocked by flap220. Thus, fluid cannot flow from chamber216to space218through bore222.

During assembly of phaser200, plates208and210are placed together in a desired orientation (for example so that flaps220cover through-bores222). Plates208and210must remain in this orientation during the remaining assembly steps for phaser200, for example, the fastening of cover plate224, plate210and plate208together. However, as shown inFIG. 13, plate210overlaps bushing212, for example, line L in direction AD1passes through bushing212and plate210. Thus, there is no feature on plate208or bushing212that holds plate210in position with respect to plate208. Extra steps, which are not always successful, must be taken to maintain the desired orientation of plates208and210. These extra steps increase the complexity and cost of assembling.

SUMMARY

According to aspects illustrated herein, there is provided a camshaft phaser, including: an axis of rotation; a stator including a radially outermost surface with a plurality of teeth; a locking plate including a first side facing in a first axial direction, a bore in the first side, and a through-bore; a check valve plate axially located between the locking plate and the stator and including a through-bore and a displaceable valve flap aligned, in the first axial direction, with the through-bore for the locking plate; and a bushing disposed in the bore in the first side and in the through-bore for the check valve plate. The bushing extends past the locking plate in the first axial direction.

According to aspects illustrated herein, there is provided a camshaft phaser, including: an axis of rotation; a stator including a radially outermost surface with a plurality of teeth; a locking plate including a first side facing in a first axial direction, a bore in the first side, and a through-bore; a check valve plate axially located between the locking plate and the stator and including a through-bore and a displaceable valve flap aligned, in the first axial direction, with the through-bore for the locking plate; and a bushing. The bushing includes a longitudinal axis extending in the first axial direction and is disposed in the bore in the first side and in the through-bore for the check valve plate. The bushing blocks movement of the check valve plate, with respect to the locking plate, in a radial direction with respect to the longitudinal axis or in a circumferential direction with respect to the longitudinal axis.

According to aspects illustrated herein, there is provided a method of operating a camshaft phaser including an axis of rotation, a stator, a rotor, a locking plate, a check valve plate axially located between the locking plate and the stator, a chamber formed at least in part by the stator, the rotor and the check valve plate, and a bushing disposed in a bore in the locking plate and in a through-bore in the check valve plate, the method including: blocking a through-bore in the locking plate with a flap in the check valve plate; displacing, in a first axial direction parallel to the axis of rotation, the flap in the check valve plate; flowing fluid through the through-bore to the chamber; displacing, in a second axial direction opposite the first axial direction, the flap in the check valve plate; blocking, with the flap, flow of the fluid from the chamber through the through-bore; and blocking, with a bushing disposed in the locking plate and in the check valve plate, movement of the check valve plate with respect to the locking plate in a radial or circumferential direction as referenced by the axis of rotation.

DETAILED DESCRIPTION

FIG. 1is a perspective view of cylindrical coordinate system10demonstrating spatial terminology used in the present application. The present application is at least partially described within the context of a cylindrical coordinate system. System10includes longitudinal axis11, used as the reference for the directional and spatial terms that follow. Axial direction AD is parallel to axis11. Radial direction RD is orthogonal to axis11. Circumferential direction CD is defined by an endpoint of radius R (orthogonal to axis11) rotated about axis11.

To clarify the spatial terminology, objects12,13, and14are used. An axial surface, such as surface15of object12, is formed by a plane co-planar with axis11. Axis11passes through planar surface15; however any planar surface co-planar with axis11is an axial surface. A radial surface, such as surface16of object13, is formed by a plane orthogonal to axis11and co-planar with a radius, for example, radius17. Radius17passes through planar surface16; however any planar surface co-planar with radius17is a radial surface. Surface18of object14forms a circumferential, or cylindrical, surface. For example, circumference19is passes through surface18. As a further example, axial movement is parallel to axis11, radial movement is orthogonal to axis11, and circumferential movement is parallel to circumference19. Rotational movement is with respect to axis11. The adverbs “axially,” “radially,” and “circumferentially” refer to orientations parallel to axis11, radius17, and circumference19, respectively. For example, an axially disposed surface or edge extends in direction AD, a radially disposed surface or edge extends in direction R, and a circumferentially disposed surface or edge extends in direction CD.

FIG. 4is a perspective view of a portion of an example embodiment of locking plate108, check valve plate110, and bushing112inFIG. 2.

FIG. 5is the perspective view ofFIG. 4with a portion of the valve flap removed to show a through-bore in the locking plate.

FIG. 6is a front view of check valve plate110inFIG. 2. The following should be viewed in light ofFIGS. 2 and 6. Plate108includes: side114facing in axial direction AD1; bore116in side114; and through-bores118. By through-bore, we mean that through-bore118extends from side114to side120facing in axial direction AD2, opposite direction AD1. In an example embodiment, bore116is a through-bore. Check valve plate110is axially located between locking plate108and stator102. Plate110includes through-bores122and displaceable valve flaps124aligned, in axial direction AD1, with through-bores118. Bushing112is disposed in bore116and in through-bore122.

FIG. 7is a detail of area7inFIG. 3. Plate110extends past locking plate108in axial direction AD1. For example, plate110extends past plate108by overlap126in direction AD1. Stated otherwise, check valve plate110does not overlap bushing112in axial direction AD1. Line L, orthogonal to axis of rotation AR, passes through bushing112and the check valve plate110. Plate110includes side128facing in axial direction AD1. In an example embodiment, bushing112does not extend to side128in axial direction AD1. In an example embodiment (not shown), bushing112extends as far as side128in axial direction AD1. Bore116is bounded by cylindrical wall130in locking plate108. In an example embodiment, bushing112includes cylindrical outer surface132in contact with cylindrical wall130.

FIG. 8is a partial cross-sectional view of camshaft phaser100inFIG. 2through a timing chamber in camshaft phaser100. Stator102includes: rotor134; chamber136; spring cover138fixed to plate108; and space140. Chamber136is bounded, at least in part, by stator102, check valve plate110and rotor134. For example, phaser100includes eight chambers136, each of which is circumferentially bounded by a respective radially inwardly extending vane142for stator102and a respective radially outwardly extending vane144for rotor134. Space140is bounded, at least in part, by spring cover138and locking plate108. Space140is in communication with through-bores118. That is, through-bore118is open to space140. Each through-bore118has a respective flap124.

For fluid pressure in space140greater than fluid pressure in a particular chamber134, fluid F1in space140is arranged to displace the flap124associated with the particular chamber136in axial direction AD1so that the through-bore118associated with the particular chamber136is open to the chamber136. Thus, fluid F1flows from space140to the particular chamber136. For fluid pressure in a particular chamber136greater than fluid pressure in space140, fluid F2in the particular chamber136is arranged to displace the flap124associated with the particular chamber136in axial direction AD2so that the through-bore118associated with the particular chamber136is blocked by the flap124associated with the particular chamber136. Thus, fluid F2cannot flow to space140through the bore118associated with the particular chamber136.

FIG. 9is a front view of an example embodiment of locking plate108, check valve plate110and bushing112inFIG. 2.

FIG. 10is a perspective view of bushing112inFIG. 9.

FIG. 11is a perspective view of a portion of check valve plate110inFIG. 9. The following should be viewed in light ofFIGS. 9 through 11. The discussion forFIGS. 2 through 8is applicable toFIGS. 9 through 11except as noted. In the example ofFIGS. 9 through 11, bushing112includes at least one groove146and check valve plate110includes at least one tab148disposed in groove146. Bushing112includes longitudinal axis LA extending in axial direction AD1. Because of the interlocking of tabs148with grooves146, bushing112blocks rotation of check valve plate110, with respect to locking plate108, circumferentially (in directions C) about longitudinal axis LA. Bushing112includes axial end surface150facing in axial direction AD1and groove146is in axial end surface150.

In an example embodiment, rotor134includes through-bore152and phaser100includes locking assembly154in through-bore152. Assembly154includes locking pin156, cartridge157and spring158. Bushing112includes indentation160facing axial direction AD1. Spring158is arranged to displace locking pin156in direction AD2into indentation160to non-rotatably connect rotor134and stator102. By non-rotatably connected elements, we mean that: the elements are connected so that whenever one of the elements rotates at a particular speed, all of the elements rotate at the particular speed; and relative rotation between the elements is not possible. Assembly154locks rotor134into a predetermined rotational position with respect to stator102. To lock rotor134and stator102together, pressurized fluid flows through channel161.

The following should be viewed in light ofFIGS. 2 through 11. The following describes a method for operating a camshaft phaser including an axis of rotation, a stator, a rotor, a locking plate, a check valve plate axially located between the locking plate and the stator, a chamber formed at least in part by the stator, the rotor and the check valve plate, and a bushing disposed in a bore in the locking plate and in a first through-bore in the check valve plate. Although the method is presented as a sequence of steps for clarity, no order should be inferred from the sequence unless explicitly stated. A first step blocks a second through-bore in the locking plate with a flap in the check valve plate. A second step displaces, in a first axial direction parallel to the axis of rotation, the flap in the check valve plate. A third step flows fluid through the second through-bore to the chamber. A fourth step displaces, in a second axial direction opposite the first axial direction, the flap in the check valve plate. A fifth step blocks, with the flap, flow of the fluid out of the chamber through the second through-bore. A sixth step blocks, with the bushing disposed in the locking plate and in the check valve plate, movement of the check valve plate with respect to the locking plate in a radial or circumferential direction as referenced by the axis of rotation. By “as referenced by the axis of rotation” we mean the axis of rotation is the point of references, for example as shown inFIGS. 1A and 1B, for the radial and circumferential directions.

In an example embodiment, blocking, with the bushing disposed in the locking plate and in the check valve plate, movement of the check valve plate with respect to the locking plate in a radial or circumferential direction as referenced by the axis of rotation includes blocking, with the bushing disposed in the locking plate and in the check valve plate, movement of the check valve plate with respect to the locking plate in the radial direction and in the circumferential direction as referenced by the axis of rotation.

In an example embodiment, a seventh step blocks, with the bushing, movement of the check valve plate, with respect to the locking plate, in a circumferential direction as referenced by a longitudinal axis extending through the bushing in an axial direction parallel to the axis of rotation. By “as referenced by the longitudinal axis” we mean the longitudinal axis is the point of references for the radial and circumferential directions.

In an example embodiment: displacing, in a first axial direction parallel to the axis of rotation, the flap in the check valve plate includes fluid pressure in a space formed at least in part by a spring cover fixed to the locking plate and the locking plate being greater than fluid pressure in the chamber; flowing fluid through the through-bore to the chamber includes flowing fluid from the space; and displacing, in the second axial direction, the flap in the check valve plate includes fluid pressure in chamber being greater than fluid pressure in the space.

In an example embodiment, an eighth step displaces a pin, disposed in part in the rotor, into an indentation in the bushing, and a ninth step non-rotatably connects the stator and the rotor.

Advantageously, camshaft phaser100and the method described above solve the problem noted above with respect to fixing a position of plate110during assembly of phaser100. For example, bushing112as shown inFIGS. 2 through 8fixes, with respect to the locking plate, a position of the check valve plate with respect to movement in circumferential directions CD1and CD2and in radial directions RD1and RD2. In addition, bushing112as shown inFIGS. 9 through 11, prevents swiveling of bushing112in direction C about longitudinal axis LA for bushing112. Thus, the correct positioning of plate110is ensured during assembly of phaser100and the need for additional time and cost increasing measures in eliminated.