A shift-by-wire (SBW) column shifter for a vehicle includes a shift lever configured to be moved to shift gears. A shaft enables the shift lever to rotate the shaft about an axis. A lever detent is coupled to the shaft, enabling the shaft to rotate the lever detent about the axis. A rotatable magnet rotates as the lever detent rotates. A magnetic sensor senses the angular position of the lever detent due to the changes in magnetic characteristics of the magnet as it rotates. A processor can command an operating gear change based on the signal output from the magnet sensor.

TECHNICAL FIELD

This disclosure is directed to shift-by-wire (SBW) column shifter for an automobile. In particular, the column shifter includes a shifter lever for shifting between gears (e.g., park, reverse, neutral, drive, etc.), wherein movement of the shifter lever electronically actuates the gear shift.

BACKGROUND

Vehicles having an automatic transmission typically include a shift control lever or a shifter mounted on a dashboard, a console, or the steering column of the vehicle. An operator of the vehicle may manually move the shifter between designated positions to change the gear position in which the transmission is commanded to operate. These gear positions include Park, Reverse, Neutral, Drive, and sometimes others, such as Low. The shifter is therefore commonly referred to by its acronym—a PRNDL or PRND shift mechanism.

Shift-by-wire (SBW) systems are known. In SBW systems, movement of the shift control lever causes electronic signals to be sent to a controller, which correspondingly electronically commands a change in the operating gear of the vehicle.

SUMMARY

In an embodiment, a shift-by-wire (SBW) column shifter is configured to mount to or within a steering column of a vehicle. The SBW column shifter includes a shift lever configured to be moved to shift gears; a shaft coupled to the shift lever to enable the shift lever to rotate the shaft about an axis; a lever detent coupled to the shaft to enable the shaft to rotate the lever detent about the axis; a magnet configured to rotate about the axis as the shift lever is moved between gears; and a sensor configured to output signals indicating an angular position of the slider magnet, wherein the signals are indicative of a command to change an operating gear of the vehicle.

In another embodiment, a SBW column shifter includes a housing; a lever detent rotatable within the housing in response to a shift lever moving to command a gear shift, the lever detent having an outer surface with a plurality of ramped surfaces leading to respective grooves therebetween; a spring mounted to the housing, the spring having a free end biased against the outer surface of the lever detent, wherein the free end slides along the ramped surfaces and presses into the grooves as the lever detent rotates during the gear shift; and a controller programmed to command a change in an operating gear as the lever detent rotates, wherein each of the grooves is associated with a respective one of the operating gears.

In another embodiment, a SBW system includes a lever detent rotatable about an axis in response to a shift lever moving to command a gear shift, the lever detent having an outer surface defining a plurality of ramped surfaces leading to respective grooves therebetween, the lever detent further having a main body with a projection extending therefrom at a location offset from the axis; a spring having a free end engaging the outer surface of the lever detent, the spring configured to slide along the ramped surfaces and mate within the grooves as the lever detent rotates to provide a force feedback to an operator during shifting; a cap secured to an outer surface of the lever detent; a magnet secured to the cap and rotatable about the axis as the lever detent rotates about the axis; a sensor fixed along the axis and spaced from the magnet, the sensor configured to output a signal that changes in response to rotation of the magnet; and a controller coupled to the sensor and programmed to command the gear shift in response to a change in the signal.

DETAILED DESCRIPTION

FIG. 1shows a perspective view of a shift-by-wire (SBW) column shifter10, according to one embodiment. An outer housing is removed for clarity of the internal components. The SBW column shifter10is configured to mount to or within a steering column of a vehicle, such as a pickup truck, car, van, sports utility vehicle (SUV), etc. The shifter10includes a shift lever12ending in a handle14extending outward from the housing and the steering column. In operation, an operator of the vehicle grabs the handle14and rotates the lever12to command a shift in the PRNDL operating gear of the vehicle (e.g., Park, Reverse, Neutral, Drive, Low, etc.).

Movement of the lever12causes mechanical movement within the SBW column shifter10that causes a corresponding electronic (“by-wire”) shift in the operating gear. The structure and function associated with the change in operating gear during an electronic shift will be described below with respect to the remaining Figures. Some main components that will be described include a lever detent20, leaf springs30, a slider magnet40, and a printed circuit assembly60having a plurality of sensors and a corresponding controller.

Referring toFIGS. 2-6, rotation of the shift lever12rotates a connected shaft16about its central longitudinal axis. The shaft16couples to the lever detent20. In one embodiment, the lever detent20has a main body21defining an aperture22therethrough, and the shaft16couples to the lever detent20through the aperture22. Rotation of the shaft16correspondingly rotates the connected lever detent20. Rotation of the lever detent20causes the slider magnet40to slide linearly, as will be described below.

The lever detent20has an outer surface with a plurality of surface features (e.g., peaks and valleys). For example, the outer surface of the lever detent20can include a plurality of sloped sidewalls24. Two of the sidewalls24can come together to form a groove25, so that the outer surface defines a plurality of grooves25, each banked by a sloped sidewall24. Lubricant or grease can be provided in the grooves25.

The grooves25engage with the leaf springs30as the lever detent20is rotated. As shown inFIG. 4, two generally identical leaf springs30can be provided (and therefore only one of the leaf springs will be described to remove redundancy). Each leaf spring30can be formed of a single continuous piece of material (e.g., steel, aluminum, etc.) that is bend to shape. Each leaf spring has one end32with a groove34formed therein to receive a fastener35(e.g., screw, bolt, etc.) to mount that leaf spring30to the housing (which is not shown for clarity). A second end36of each leaf spring30is bent, curved, or rounded to shape to facilitate a sliding and pivotal movement along the sidewalls24.

When the vehicle is operating in a first gear (e.g., PRND), the curved second end36is located within one of the grooves25of the lever detent20. During a shift of operating gears, the lever detent20rotates, causing deflection or bending of the springs30in which the second end36of each spring30slides along one of the sidewalls24, radially away from the rotating shaft16. This bends the spring30about the fixed point of attachment (e.g., the fastener35). The spring bias against the lever detent20provides a force or mechanical feedback to the driver, simulating a feel of a resistance force that would otherwise be present in a traditional non-by-wire gear shifter with mechanical linkages. Once the lever detent20has been rotated far enough, the springs30are able to bend back to their biased position in which the second end36returns radially inward to rest within another one of the grooves25. When in position within one of the grooves25, the spring30maintains the lever detent20in a fixed location until another change in operating gear is commanded by the driver.

While a leaf spring is described herein, it should be understood that the present disclosure is not limited to such a particular type of spring. Instead, the spring may be any type of spring that can provide mechanical feedback to the driver by pressing against the lever detent during rotation of the lever detent when shifting gears. For example, the spring may be of the type that compresses and expands in a linear path as the lever detent is rotated.

In one embodiment, the number of grooves25in the lever detent20can be equal to the number of operating gears (e.g., PRND) available for selection by the driver. For each operating gear selected, the spring30is received within a designated groove25associated with that selected gear, which maintains the slider magnet40to a corresponding designated linear position for that selected gear.

Rotation of the lever detent20causes a corresponding linear sliding movement of the slider magnet40. In one embodiment, the main body21of the lever detent20has a projection26extending therefrom. In one embodiment, the projection26is spherical, rounded, or frusto-spherical. The slider magnet40has an upper surface42facing the lever detent20. The upper surface42has a groove44formed therein, which may be defined by or flanked within sidewalls46extending upward toward the lever detent20to direct movement of the projection26. The groove44is sized and configured to receive the projection26in a sliding manner. The groove44extends linearly across the width of the slider magnet40, and creates a linear pathway for the projection26to slide within. As the lever detent20is rotated, the projection26slides within the groove44. And, the slider magnet40is bound to move linearly (e.g., forward and backward) within linearly-extending rails or walls47of a slider-magnet housing48. The slider-magnet housing48may be mounted or fixed relative to the housing, such that the slider magnet40can slide within the stationary slider-magnet housing48during gear shifts. Thus, rotational movement of the lever detent20forces the projection26to move within the groove44of the slider magnet40, causing the slider magnet40to move along a linear pathway. Rotational movement (of the lever detent) is therefore converted into linear movement (of the slider magnet) in this manner.

The slider magnet40is referred to as a “magnet” because it is at least partially magnetic. For example, the slider magnet40may be entirely made of a ferromagnetic material such as iron, nickel, cobalt, rare-earth metals, etc. In another embodiment, a ferromagnetic material is impregnated or bonded to a base material of the slider, such as aluminum, steel, etc. The slider magnet40may also be a multipolar magnet, built from multiple individual magnets, with each individual magnet serving an individual purpose of activating one of the sensors (explained below) when passing by. The slider magnet40may also be a single magnet with multiple poles. Furthermore, the use of the term “slider magnet” may also refer to the housing that surrounds or contains the magnet itself.

As can be seen inFIG. 5for example, a printed circuit assembly (PCA, also referred to as a printed circuit board or printed circuit board assembly)60is provided, fixed relative to the housing of the SBW column shifter10at a spaced location from the slider magnet40. The PCA60includes a plurality of contactless sensors62configured to detect the presence and/or location of the slider magnet40by outputting signals in response to the presence of the magnetic field of the slider magnet40being aligned therewith. In one embodiment, the sensors62are Hall effect sensors each having a transducer that varies its output voltage in response to the magnetic field from the slider magnet40. In particular, the Hall effect sensors can output a magnetic field that varies in response to a changing proximity of the slider magnet40; when the magnetic field is increased above a certain low threshold, it can be determined (e.g., via an associated processor or controller) that the slider magnet40is in a location aligned with that sensor. The sensors62may be located along the linear path that the slider magnet40travels along during gear shifts. Thus, when the slider magnet40is moved to a particular location when shifting from one operating gear to another, one of the sensors62may be deactivated (e.g., magnetic field dropping below the threshold) while another sensor62may be activated (e.g., magnetic field increasing above the threshold).

The sensors62are coupled to an associated processor, microprocessor, controller or the like (hereinafter referred to as a processor) that can be either on-board the PCA60or off-board. In one embodiment, each of the sensors62is located at a particular location such that each respective sensor62is activated when the slider magnet40is in a particular location associated with the shifter10being set in a particular operating gear. In another embodiment, multiple sensors62may be located intermittently and in various locations, and a pattern of activated sensors indicates the position of the slider magnet40. For example, when the shifter10is in Park, the slider magnet40may be located such that a first and a second sensor are activated. When the operator shifts gears to Reverse, the second and a third sensor may be activated while the first sensor is deactivated. Thus, while the second sensor is active for both the Park and Reverse gear selections, the overall pattern of sensor activity can be analyzed by the processor to determine which gear is selected by the driver. It should be understood that this is not limiting but merely an example of the concept of having an individual sensor that could be activated to indicate different gear selections. In other examples, a particular sensor might be activated for one or multiple gear selections including Park, Reverse, Neutral, Drive, Low, etc. The transmission can be commanded to be shifted by the processor accordingly. This operates the “by-wire” nature of the shifter10.

The slider magnet40may be spring-biased to slide to a designated position in the event of a failure or break in the connection between the lever detent20and the slider magnet40. For example, if an extremely large force is provided to the shifter10, mechanical failure in the connection between the projection26and the groove44of the slider magnet40is always a possibility. To account for this possibility, a spring50biases the slider magnet40toward an end of the slider-magnet housing48. In one embodiment, a first end of the spring50is connected to a tab52extending upward from a main tray body of the slider-magnet housing48, and a second end of the spring is connected to a raised region54of the slider magnet40. In the event of such an aforementioned mechanical failure in the connection at the projection26and groove44, the spring50pulls the slider magnet40to a position that may only be attainable during such a failure. In other words, the slider magnet40slides to a linear position that it would not otherwise be able to slide to during normal shifting between gears. An associated sensor64(that can be a Hall effect sensor like the other sensors62) can be located at a position such that it is activated when the slider magnet40is pulled to the designated position via the spring50. That sensor64outputs a signal in response to the slider magnet40being in its designated position associated with a failure or break in the connection between the lever detent20and the slider magnet40. The associated processor can infer from receiving a signal from the sensor64that such a mechanical failure or break has occurred, and can output a corresponding alert (e.g., video, audio, etc.) alerting the driver of a failure in the shifter10. Alternatively, the alert can be a signal sent to an on-board diagnostic (OBD or OBD-II) port for a technician to diagnose the signal and determine that a failure in the shifter10has occurred.

To facilitate the proper movement of the slider magnet40in the event of such a mechanical failure, the lever detent20is provided with a region of thinned or weakened material. For example, the projection26may include a detent shaft27, with the spherical or frusto-spherical region extending from the detent shaft27. The detent shaft27may also be another shape, such as cylindrical. The detent shaft27may extend from a larger shaft29that has a diameter that exceeds that of the detent shaft27. In the event of an extremely large force being applied to the lever detent, the break between the lever detent20and the slider magnet40may be concentrated at the detent shaft27to facilitate the break, allowing the slider magnet40to cleanly break away from the lever detent20and slide to its designated position aligned with the sensor64.

FIG. 6shows a processor or CPU70that is connected via wires72and a wire connection74to the PCA60and associated sensors. It should be understood that the CPU70may also be located directly on-board the PCA60. In one embodiment, the CPU70is responsible for receiving the signals output from the sensors62,64, processing those signals, and commanding the shift in operating gears described above. As such, the CPU70can be coupled to a transmission control unit (TCU), powertrain control unit (PCU), or the like that is responsible for commanding the shift in operating gears. The CPU70can be provided with or be in communication with a storage medium that associates activated sensors with an operating gear that should be selected.

FIG. 7illustrates an SBW column shifter110according to another embodiment with certain associated reference numbers increased by 100 relative to the embodiment shown inFIGS. 1-6. Once again, the SBW column shifter110of this embodiment includes a lever detent120, one or more leaf springs130, and a printed circuit assembly (PCA)160. However, in this embodiment, no slider magnet is provided. Instead, a rotational position sensor assembly140is provided for sensing the rotational position of the lever detent120, and thus the relative position of the shift lever12and the desired operating gear (e.g., park, reverse, neutral, drive, etc.).

The lever detent120may be coupled to a shaft in similar fashion as the previous embodiments described such that the lever detent120rotates as the shift lever12is pulled to rotate the shaft. As the lever detent120is rotated, the leaf springs130engage corresponding sidewalls and grooves of the lever detent in each selected operating gear. In general, as the lever detent is rotated between each operating gear, the rotational position sensor assembly140detects the rotational position of the lever gear and thus the selected gear; a processor (e.g., on-board the PCA160or off-board) can command an operating gear change based on the output of the rotational position sensor assembly140.

The SBW column shifter110also includes a housing111connected to a PCA cover113to contain or house the PCA and associated components therein. The PCA160may be fixed to the housing111via fasteners115, and the PCA cover113may be fixed to the housing111via fasteners117. Similar structure may also be implemented in the other embodiments described herein.

Referring toFIGS. 7A-7C, the rotational position sensor assembly140is generally comprised of a magnet141, a detection cap145, and a sensor143, along with the lever detent120and the PCA160. The sensor143may be placed on or part of the PCA160(e.g., on the printed circuit board). When assembled, the magnet141may be spaced from the PCA160at a location vertically aligned with the sensor143. This is an “on-axis” location, although in other embodiments the rotational position sensor assembly may include an “off-axis” sensor in which the sensor is not coaxial with the rotational point of the magnet. In an embodiment, the magnet141is housed within the detection cap145that is fixed to the lever detent120via fasteners119. The magnet141can be aligned with the axis of rotation such that as the gear lever is shifted, the magnet141rotates about a fixed central point.

The magnet141and sensor143cooperate to sense rotation. The relationship between the magnet141and the sensor143is shown generally inFIG. 7C. In short, the sensor143senses changes in the magnetic characteristics of the magnet141as the magnet141rotates, and outputs a signal that corresponds to the rotational position of the magnet141based on the detected magnetic characteristic. There are various ways to accomplish this. For example, the strength of the magnetic field can be sensed by the sensor143, and the corresponding strength can be programmed or calibrated to a specific angular position of the center shaft, and thus a specific operation gear selection. The sensor143may be a sensor in the model line MLX by MELEXIS, or an AS5030 (or similar model of angle position on-axis sensor) by AMS, for example. These are merely examples of sensors that can detect a change in the rotational position of the magnet due to the changes in the polarity position, magnetic field strength, and the like.

The magnet141may be overmolded or otherwise secured to the detection cap145. Overmolding of the magnet141can help secure the magnet141within the synthetic material of the detection cap145without interfering with the magnetic flux or properties of the magnet141.

Based on the detected angular position of the magnet141, the sensor143can output a signal to activate a by-wire change in the selected operating gear of the vehicle. In other words, each detected angle of rotation of the magnet can be calibrated to match a corresponding operating gear selection. This is shown generally inFIGS. 8A-8D, which shows a bottom view of the SBW column shifter110with the printed circuit board removed for clarity of view.

FIGS. 8A-8Dshow the use of the SBW column shifter110as the shift lever12is pulled or rotated to select different operating gears.FIG. 8Ashows the SBW column shifter110in a Park position,FIG. 8Bshows the SBW column shifter110in a Reverse position,FIG. 8Cshows the SBW column shifter110in a Neutral position, andFIG. 8Dshows the SBW column shifter110in a Drive position.

In the Park position ofFIG. 8A, an axis151of the shift lever12is aligned with a zero position153, such that the angle between the axis151and the zero position153is α0=0. At this location, the sensor143detects the magnetic characteristics of the magnet141, and correspondingly commands a Park gear to be engaged. Once the shift lever12is in the Park position, the PCA160can send a signal to the vehicle ECU, ECM or directly to the transmission (not shown) that the start key or start button can be activated. In typical vehicles, a mechanical linkage is present between the Park position and the ability to start the vehicle via key or button, such that the vehicle can only be started when the shift lever is in the Park position due to mechanical constraints. The arrangement and use of the PCA160along with the magnet141can remove this mechanical linkage between the Park position and a start key or start button, allowing for the removal of parts. Likewise, a mechanical linkage is typically present between the Park position and the ability to turn the vehicle off via key or button, such that the vehicle can only be turned off when the shift lever is in the Park position due to mechanical constraints. The arrangement and use of the PCA160along with the magnet141can remove this mechanical linkage between the Park position and the key-off button or key position, allowing for removal of parts.

In the Reverse position ofFIG. 8B, the shift lever12and connected detection cap145with magnet141have been rotated relative to the sensor143on the printed circuit board (not shown) to a position such that the angle between the axis151and the zero position153is a first angle α1>α0. The processor connected to the sensor143can be programmed to command a Reverse operating gear when the detected angle is equal to (or within a threshold of) α1.

In the Neutral position ofFIG. 8C, the shift lever12and connected detection cap145with magnet141have been rotated relative to the sensor143on the printed circuit board (not shown) to a position such that the angle between the axis151and the zero position153is a second angle α2>α1. The processor connected to the sensor143can be programmed to command a Neutral operating gear when the detected angle is equal to (or within a threshold of) α2.

In the Drive position ofFIG. 8D, the shift lever12and connected detection cap145with magnet141have been rotated relative to the sensor143on the printed circuit board (not shown) to a position such that the angle between the axis151and the zero position153is a third angle α3>α2. The processor connected to the sensor143can be programmed to command a Park operating gear when the detected angle is equal to (or within a threshold of) α3.

It should be understood that there could be more than just the four standard PRND positions. For example, in other embodiments, there can be one or more of the following shift positions: first drive (D1), second drive (D2), manual (M), low (L) positions. Any one or more of these additional shift positions can also be calibrated such that a detected rotational position of the magnet141can correspond to a respective one of these additional shift positions. In short, the teachings of this disclosure should not be limited to just Park, Reverse, Neutral, and Drive.

The technology described above with reference to at least the embodiment ofFIGS. 7-8has the capability to send signals via CAN bus or LIN bus to the vehicle's transmission control unit to inform the transmission control unit that the vehicle is either in Park position or out of Park position. Certain features of the vehicle can be utilized only when the transmission is in Park or is out of Park, and this feature can provide such a signal. For example, when α0=0, a signal can be sent that the vehicle is in park, and thus enabling features (e.g., automatically unlocking doors, as one of many examples). This can eliminate the need for a separate sensor that determines that the vehicle is in park, or the technology disclosed herein can be used as a redundancy safety mechanism.

While illustrated as one processor70, the CPU may be part of a larger control system and may be controlled by various other controllers throughout the vehicle, such as a vehicle system controller (VSC). It should therefore be understood that the CPU70and one or more other controllers responsible for receiving signals from the PCA60and commanding the associated shift in operating gears can collectively be referred to as a “controller”. The controller may include a microprocessor or central processing unit (CPU) in communication with various types of computer readable storage devices or media. Computer readable storage devices or media may include volatile and non-volatile storage in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM), for example. KAM is a persistent or non-volatile memory that may be used to store various operating variables while the CPU is powered down. Computer-readable storage devices or media may be implemented using any of a number of known memory devices, such as PROMs (programmable read-only memory), EPROMs (electrically PROM), EEPROMs (electrically erasable PROM), flash memory, or any other electric, magnetic, optical, or combination of memory devices capable of storing data, some of which represent executable instructions, used by the controller in controlling the engine or vehicle.