Coupling and Control Assembly Including a Non-Contact, Inductive Displacement Sensor

Abstract

A coupling and control assembly including a non-contact, inductive displacement sensor is provided. The assembly includes a controllable coupling assembly including first and second coupling members supported for rotation relative to one another about a rotational axis. The first coupling member has a first coupling face which has a sensor pocket which receives the sensor. A control member made of an electrically conductive material is mounted for controlled, small-displacement, shifting movement relative to the sensor. The sensor is configured to create a magnetic field to induce eddy currents in the electrically conductive material of the control member wherein shifting movement of the control member changes a magnetic field caused by the eddy currents. The sensor provides a position feedback signal for vehicle transmission control, wherein the signal is correlated with the position of the control member.

Claims

1. A coupling and control assembly including a non-contact, inductive displacement sensor, the assembly comprising: a controllable coupling assembly including first and second coupling members supported for rotation relative to one another about a rotational axis, the first coupling member having a first coupling face having a locking member pocket which receives a locking member, the first coupling face also having a sensor pocket which receives the sensor, the second coupling member having a second coupling face having a set of locking formations; a control member made of an electrically conductive material and mounted for controlled, small-displacement, shifting movement between the first and second coupling faces relative to the locking member and the sensor for controlling position of the locking member, the control member allowing the locking member to engage one of the locking formations in a first position of the control member and the control member maintaining the locking member in the locking member pocket in a second position of the control member; and a non-contact, inductive displacement sensor configured to create a magnetic field to induce eddy currents in the electrically conductive material of the control member wherein shifting movement of the control member changes a magnetic field caused by the eddy currents, the sensor providing a position feedback signal for vehicle transmission control, wherein the signal is correlated with the position of the control member.

2. The coupling and control assembly as claimed in claim 1, wherein the control member is rotatable about the rotational axis and wherein the sensor is a rotary position sensor.

3. The coupling and control assembly as claimed in claim 1, wherein the control member is an electrically conductive selector plate.

4. The coupling and control assembly as claimed in claim 1, wherein the control member includes an aperture which is at least partially axially aligned with the sensor during shifting movement between the first and second positions to change the magnetic field caused by the eddy currents.

5. The coupling and control assembly as claimed in claim 1, wherein the sensor includes a printed circuit board and wherein the control member is supported proximate the board.

6. The coupling and control assembly as claimed in claim 1, wherein the sensor includes a transmitter coil having a resonant frequency which changes when the control member moves.

7. The coupling and control assembly as claimed in claim 1, wherein the first and second coupling members are pocket and notch plates, respectively.

8. The coupling and control assembly as claimed in claim 1, wherein the locking member is a strut.

9. The coupling and control assembly as claimed in claim 1, wherein the control member is an apertured control member.

10. A clutch and control assembly including a non-contact, inductive displacement sensor, the assembly comprising: a controllable clutch assembly including first and second clutch members supported for rotation relative to one another about a rotational axis, the first clutch member having a first clutch face having a plurality of locking member pockets, each of the pockets receiving a locking member, the first clutch face also having a sensor pocket which receives the sensor, the second clutch member having a second clutch face having a set of locking formations; a control member made of an electrically conductive material and mounted for controlled, small-displacement, shifting movement between the first and second clutch faces relative to the locking members and the sensor for controlling position of the locking members, the control member allowing the locking members to engage the locking formations in a first position of the control member and the control member maintaining the locking members in their locking member pockets in a second position of the control member; and a non-contact, inductive displacement sensor configured to create a changing magnetic field to induce eddy currents in the electrically conductive material of the control member wherein the shifting movement of the control member changes a magnetic field caused by the eddy currents, the sensor providing a position feedback signal for vehicle transmission control, wherein the signal is correlated with the position of the control member.

11. The clutch and control assembly as claimed in claim 10, wherein the control member is rotatable about the rotational axis and wherein the sensor is a rotary position sensor.

12. The clutch and control assembly as claimed in claim 10, wherein the control member is an electrically conductive selector plate.

13. The clutch and control assembly as claimed in claim 10, wherein the control member includes an aperture which is at least partially axially aligned with the sensor during shifting movement between the first and second positions to change the magnetic field caused by the eddy currents.

14. The clutch and control assembly as claimed in claim 10, wherein the sensor includes a printed circuit board and wherein the control member is supported proximate the board.

15. The clutch and control assembly as claimed in claim 10, wherein the sensor includes a transmitter coil having a resonant frequency which changes when the control member moves.

16. The clutch and control assembly as claimed in claim 10, wherein the first and second clutch members are pocket and notch plates, respectively.

17. The clutch and control assembly as claimed in claim 10, wherein each of the locking members is a strut.

18. The clutch and control assembly as claimed in claim 10, wherein the control member is an apertured control member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] FIG. 1 is an exploded, perspective view of a prior art overrunning coupling and clutch assembly which is modified in accordance with at least one embodiment of the present invention;

[0053] FIG. 2 is a top plan view, partially broken away, of a pocket plate modified in accordance with at least one embodiment of the present invention;

[0054] FIG. 3 is a side elevational view, partially broken away, of the modified pocket plate of FIG. 2; and

[0055] FIG. 4 is a top plan view, partially broken away, of the modified pocket plate of FIGS. 2 and 3 but now including an apertured selector plate, a sensor, and a vehicle controller.

DETAILED DESCRIPTION

[0056] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0057] Referring again to the drawing figures, FIG. 1 is an exploded perspective view of a prior art overrunning clutch or coupling assembly, generally indicated at 10, which is modified in accordance with at least one embodiment of the present invention. However, it is to be understood that the present invention can be utilized with a wide variety of properly modified selectable clutches, such as clutches having three or more operating modes or states. In fact, the present invention may be used with controllable mechanical diodes (CMDs) having an infinite number of operating modes or mechanical states.

[0058] As described in U.S. Pat. No. 8,602,187, and published in U.S. patent application No. 2014/0190785, both assigned to the assignee of the present application, the assembly 10 includes an annular reverse pocket plate or first outer coupling member, generally indicated at 12. An outer axially-extending surface 14 of the plate 12 has external splines 16 for coupling the plate 12 to the inner surface of a transmission case (not shown). An inner radially extending surface or coupling face 18 of the plate 12 is formed with spaced pockets 20 in which reverse struts 22 are pivotally biased outwardly by coil springs (not shown) disposed in the pockets 20 under their respective struts 22. Preferably, twelve reverse struts 22 are provided. However, it is to be understood that a greater or lesser number of reverse struts 22 may be provided.

[0059] The assembly 10 also includes a control member or element in the form of a selector slide plate, generally indicated at 26, having a plurality of spaced apertures 28 extending completely therethrough to allow the reverse struts 22 to pivot in their pockets 20 and extend through the aperture 28 to engage spaced locking formations or ramped reverse notches (not shown) formed in radially extending surface or coupling face of a forward or inner pocket plate or coupling member, generally indicated at 34, when the plate 26 is properly angularly positioned about a common central rotational first axis 36 by an output member in the form of an actuator pin or arm 38. The pin 38 is coupled or secured to the plate 26 to move therewith.

[0060] The pin 38 may extend through a notch or elongated slot formed through a wall or wall portion of an outer circumferential end wall of the plate 12 as shown in U.S. Pat. No. 8,602,187. The wall may be a common wall separating and shared by the first coupling member 12 and a housing of the control system. The elongated slot may extend between and thereby communicate an inner surface of the housing and an inner surface of the wall of the first coupling member 12. The pin 38 may move in the slot between different use positions to cause the plate 26 to slide or shift between its control positions to alternatively cover or uncover the struts 22 (i.e. to engage or disengage the reverse struts 22, respectively).

[0061] The plate 34 comprises a splined ring having internal splines 46 formed at its inner axially extending surface 48. A radially extending surface 50 or coupling face spaced from the other coupling face (not shown) of the plate 34 has a plurality of spaced pockets 52 formed therein to receiver a plurality of forward struts 54 therein which are pivotally biased by corresponding coil springs (not shown). Preferably, fourteen forward struts 54 are provided. However, it is to be understood that a greater or lesser number of forward struts 54 may be provided.

[0062] The assembly 10 may also include a second outer coupling member or notch plate, generally indicated at 58, which has a plurality of locking formations, cams or notches (not shown) formed in a radially extending surface or coupling face (not shown) thereof by which the forward struts 54 lock the forward plate 34 to the notch plate 58 in one direction about the axis 36 but allow free-wheeling in the opposite direction about the axis 36. The notch plate 58 includes external splines 64 which are formed on an outer axial surface 66 of the plate 58 and which are received and retained within axially extending recesses 68 formed within the inner axially extending surface 47 of the outer circumferential end wall of the plate 12.

[0063] The assembly 10 may further include a snap ring, generally indicated at 72, having end portions 74 and which fits within an annular groove 76 formed within the inner surface 47 of the end wall of the plate 12 to hold the plates 12, 26, 34 and 48 together and limit axial movement of the plates relative to one another.

[0064] The pin 38 has a control position to disengage the reverse struts 22. In one embodiment, a pin 38 is rotated about 7° in a forward overrun direction about the axis 36 to rotate the selector plate 26 to, in turn, allow the reverse struts 22 to move from their disengaged position in their pockets 20 to their engaged position with the notches (not shown) of the plate 34.

[0065] As described above, a typical selectable one-way clutch consists of a notch plate, a pocket plate, a selector plate, struts, springs, and a snap ring. The notch plate and the pocket plate rotate relative to one another. The struts, when engaged, prevent rotation in one direction but the selector plate can prevent the struts from engaging. The position of the selector plate is typically controlled by a hydraulically actuated mechanism called an actuator arm.

[0066] The prior art way to identify the position of the selector plate is by sensing the position of the actuator arm. If the actuator arm were to detach from the selector plate, there would no longer be a way to find the position of the selector plate. The valve's position has previously been measured with Hall cells but the position of the valve was measured on a prototype basis only.

[0067] The importance of knowing the position of the selector plate is that if the part were to lock in the wrong conditions the vehicle would be suddenly pulled into first gear. A vehicle pulled into first gear on the highway could damage the engine from extreme engine speeds. Monitoring the selector plate position can help protect against the risk of unwanted clutch state changes. The sensor could also detect if the actuator arm is damaged and restrict the transmission from shifting.

[0068] Due to the above noted scenarios, there is need for a more direct way to find the position of the openings in the selector plate.

[0069] An object of at least one embodiment of the present invention is to locate the selector plate directly with an eddy current or inductive position sensor. As disclosed hereinbelow, location or position of a selector plate 26′ can be equated to changes in the output of an eddy current or inductive displacement sensor 100.

[0070] Referring now to FIGS. 2, 3 and 4 there is illustrated a pocket plate 12′ and a selector plate 26′, both of which have been modified from the assembly 10 of FIG. 1 to allow a non-contact, inductive displacement sensor, generally indicated at 100, to directly sense control member or selector plate movement. The sensor 100 may include a coil PCB 116 on which one or more coils 110 are supported and an electronics PCB 114 which supports the active electronics (not shown) of the sensor 100.

[0071] Parts illustrated in FIGS. 2, 3 and 4 which are the same as the parts of FIG. 1, such as the struts 26, have the same reference number. Parts illustrated in FIGS. 2, 3 and 4 which are part of the modified assembly have the same reference number as the corresponding part of the assembly 100, but a single prime designation (i.e. a surface 14′, splines 16′, a coupling face 18′, pockets 20′, a plate 26′ and apertures 28′). New features or parts are given a new reference number such as the sensor 100, an aperture 102 formed through a wall of the pocket plate 12′ and a wedge-shaped hole 104 formed in the selector plate 26′. The hole 104 is a dedicated opening in the selector plate 26′ for the sensor 100 to target. The sensor 100 is mounted below the selector plate 26′ in a sensor pocket formed in the pocket plate 12′. The aperture 102 has a size and shape to allow the coil PCB 116 of the sensor 100 to be inserted through a side wall of the pocket plate 12′ and into the sensor pocket formed in the coupling face 18′ of the pocket plate 12′. The electronics PCB 114 typically remains outside the pocket plate 12′. The two PCB's 114 and 116 may be stacked vertically and horizontally offset from one another.

[0072] The eddy current sensor 100 works by creating, changing magnetic fields in one or more coils 110 of the sensor 100 to induce loops of eddy currents in the electrically conductive material of the selector plate 26′. The resultant circular flow of electric current in the conductive material creates an electromagnet, which opposes the magnetic field of the coil 110. The sensor 100 can measure the change in the magnetic field caused by the eddy currents and this change correlates to how close the electrically conductive material of the selector plate 26′ is to the sensor 100. There is a coupling between the coil's magnetic field and the eddy currents similar to the coupling between the windings of a transformer that creates a mutual inductance. The coupling is distance dependent and changes in coupling affect the inductance of the coil 100 and coupling system. The change in inductance is measured from the change in the resonant frequency of the coil 100. As the current reaches a steady state amplitude the inductance of the system can be calculated from the measured time constant and known resistance of the sensor's electronics. The sensor 100 can be modeled as a lossy inductor in parallel with a capacitor.

[0073] With the inductance, capacitance and resistance of the sensor 100 known, the resonant frequency can be calculated.

[0074] The eddy current or inductive position sensor 100 outputs a value to a vehicle controller 112 for use in controlling the vehicle's transmission that is relatively high when the sensor 100 is below the air gap or hole 104 and is relatively low when the sensor 100 is below a non-apertured portion of the selector plate 26′.

[0075] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.