Abstract:
A throttle control cartridge has a circuit board carrying a Hall-effect sensor, the position of which is fixed in a housing carrying a cam. A shaft carrying a magnet is rotatably and translatably disposed with respect to the housing and carries a cam follower that engages the cam and translates the shaft with respect to the housing when the shaft is rotated with respect to the housing in at least one of two opposed angular directions. The cam and the cam follower have at least first and second pairs of cam surfaces in which a first cam surface is disposed at a different cam or helix angle then the second cam surface. A redundant stop is cooperatively formed between the cam follower and splines on the shaft to limit axial translation of the cam follower in one direction of rotation of the shaft relative to the housing.

Description:
This application claims the benefit to the filing date of U.S. Provisional Patent Application Ser. No. 60/879,661 filed Jan. 10, 2007, the contents of which are incorporated herein in their entirety. 

   TECHNICAL FIELD 
   This invention relates to an engine throttle control apparatus. 
   BACKGROUND OF THE INVENTION 
   Control handles are often used for controlling the speed of a vehicle that is steered by a handle bar, such as a motorcycle, a snowmobile or a personal watercraft. such vehicles may also be equipped with cruise control to maintain a set speed and a control handle or handgrip to control the throttle of an engine manually as well as deactivate cruise control. 
   In a throttle position sensor with a cruise-off feature, the throttle is usually spring loaded with a torsion spring against a stop. In this particular application, an off-throttle position was needed to turn the cruise control off. This was accomplished with a cam that would be steep enough to stop the throttle return force and momentum but at the same time not be too steep to make the off-throttle force too high. This created an issue that required a fine tuned balance between the force of the torsion spring and the cam angle and it became difficult to have the desired feel for the throttle and at the same time not overshoot the idle position. 
   For a throttle by wire twist grip sensor, it is essential to have a redundant stop for safety reasons. Due to the small packaging area, a space efficient redundant stop must be designed. A traditional stop is designed as the primary stop. Due to the confined space, the primary stops provide only a small safety factor. 
   SUMMARY OF THE INVENTION 
   A throttle control cartridge includes a first member carrying a Hall-effect sensor; a second member carrying a magnet, the second member being rotatable and translatable with respect to the first member; means to position the first member with respect to the second member so that the Hall-effect sensor senses a predetermined magnetic flux density of the magnet; a cam having a cam surface at a first cam angle carried by one of the first and second members and a cam follower having a cam follower surface at second cam angle different from first cam angle carried by another of the first and second members. The cam follower moves away from the cam responsive to rotation of the second member with respect to the first member in the first direction and engages the cam and translates the other of the first and second members with respect to the one of the first and second members responsive to rotation of the second member with respect to the first member in an opposition direction; means to change the magnetic flux density sensed by the Hall-effect sensor in one direction responsive to rotation of the second member with respect to the first member in a first direction; and means to change the magnetic flux density sensed by the Hall-effect sensor in an opposite direction responsive to translation of the second member with respect to the first member. 
   A control cartridge in which a redundant stop includes axially extending splines formed on the second member; and spline engagement members carried on the cam follower to control axial movement of the cam follower along the second member during rotation of the second member. The splines on the second member have ends such that engagement of the spline engagement members on the cam follower with the ends of the spline defines the redundant stop of rotation of the second member. 
   The present throttle control cartridge utilizes unique cam and cam follower surfaces wherein a first cam surface, which may be a double-sided cam surface is disposed at a different helix angle then an opposed second cam surface, which may also be a double-sided cam surface, for throttle feel during rotation of the throttle in either positive or negative directions. 
   The throttle control cartridge also includes a unique redundant stop limiting maximum angular rotation of the throttle in the event that the primary stops by the rotatable shaft in the throttle control cartridge and a stop member fixed to the housing fails. The spline engagement members of the cam follower bottom out and engage the ends of the spline at a maximum stop position of throttle rotation. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various features, advantages and other uses of the present invention will become more apparent by referring to the following detailed description and drawing in which: 
       FIG. 1A  is a side elevational view of a motorcycle incorporating a throttle control according to the following disclosure; 
       FIG. 1B  is a schematic cross-sectional view of a control handle with a control cartridge; 
       FIG. 2  is an exploded, perspective view of one aspect of a throttle control; 
       FIG. 3  is a perspective view of the throttle control sensor shown in  FIG. 2 ; 
       FIG. 4  is a partial, enlarged view showing the attachment of the spacer to the sensor tube; 
       FIG. 5  is an enlarged, partial elevational view showing the interconnection of the stop and the sensor tube; 
       FIG. 6  is a perspective, assembled view of the PC board assembly shown in  FIG. 2 ; 
       FIG. 7  is a perspective view showing the relative positions of the sensor assembly shown in  FIG. 6  and the rotor; 
       FIG. 8  is an enlarged perspective view of the cam housing shown in  FIG. 2 ; 
       FIG. 9  is a perspective view showing the assembly of the PC board to the cam housing; 
       FIG. 10  is an enlarged, perspective view of the cam surfaces at one end of the cam housing shown in  FIG. 8 ; 
       FIG. 11  is a perspective view of the rotor assembly with the outer tube removed; 
       FIG. 12  is a side perspective view of the rotor and magnet of the rotor assembly shown in  FIG. 11 ; 
       FIG. 13  is an enlarged, cross sectional view showing the mounting of the magnet in the rotor shown in  FIG. 11 ; 
       FIGS. 14 and 15  are front and rear perspective views, respectively of the stop shown in  FIG. 2 ; 
       FIG. 16  is a perspective view of the stop-to-rotor interface; 
       FIG. 17  is an enlarged, cutaway view of the circled portion in  FIG. 16 ; 
       FIG. 18  is a lateral cutaway view also showing the stop-to-rotor interface; 
       FIG. 19  is an end, pictorial view of the primary rotor stop and cap; 
       FIG. 20  is an exploded, perspective view showing the redundant stop surfaces on the rotor; 
       FIG. 21  is an enlarged, perspective view of another aspect of the redundant stop; 
       FIG. 22  is an enlarged, perspective view showing the connection of the tube and stop to the sensor cartridge in the tube; 
       FIG. 23  is a longitudinal cutaway view of the assembly shown in  FIG. 22 ; 
       FIG. 24A  is an enlarged, perspective view of the cam follower shown in  FIG. 2 ; 
       FIG. 24B  is a perspective view showing the movement of the cam follower on the rotor splines; 
       FIG. 25A  is a perspective view of the cam follower; 
       FIG. 25B  is a lateral, cross sectional view showing the cam follower-to-rotor interface; 
       FIG. 26  is an enlarged view of the circled area of  FIG. 25 ; 
       FIGS. 27A ,  27 B, and  27 C show respective positions of the cam housing and cam follower from idle position, clockwise throttle movement and counter clockwise throttle movement; 
       FIG. 28  is an enlarged, transparent view showing the mounting of the end cap and throttle on the cartridge shown in  FIG. 2 ; 
       FIG. 29  is a longitudinal, cross-sectional view to the assembled end cap, throttle and cartridge shown in  FIG. 28 ; and 
       FIG. 30  is a longitudinal, cross sectional view showing the interior of the throttle depicted generally in  FIGS. 28 and 29 . 
   

   DETAILED DESCRIPTION 
   Before any aspects of throttle control are explained in detail, it is to be understood that the throttle control is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The throttle control is capable of other aspects and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled,” and variations thereof, are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
   Referring now to  FIGS. 1A and 2B , there is depicted a control cartridge  30  that can be inserted into a handle bar of a motorcycle or other self-propelled vehicle that is steered by the handle bar. The cartridge  30  transmits an electric signal that allows the operator to control a first device such, as an engine throttle control device and a second device, such a cruise control device. 
     FIG. 1A  illustrates a motorcycle  10  including a front wheel  14 , a rear wheel  18 , an engine  20  and a frame  22  interconnecting the front and rear wheels  14 ,  18 . The motorcycle  10  also includes a steering assembly  24  coupled to the frame  22 . The steering assembly  24  is pivotable about a steering axis and includes a handlebar  26  for imparting such pivotal motion to the steering assembly  24 . The handlebar  26  includes a left-side grip (now shown) and a right-side grip  28  that are grasped by an operator to control the motorcycle  10 . 
   The left-side grip is secured to the left-hand end portion of the handlebar  26  and the right-side grip or throttle grip  28  is secured to the right-hand end portion of the handlebar  26 . A left control housing (not shown) may be positioned inwardly of the left-side grip, and a right control housing  29  is positioned inwardly of the throttle grip  28 . The left control housing and the right control housing  29  are secured to the motorcycle handlebar  26 . The left control housing and the right control housing  29  include operator switches that communicate with and control various devices on the motorcycle  10 , such as the headlight, the starter, the turn signals, the horn, and other devices as is well known in the art. The illustrated handlebar  26  is a generally continuous hollow tube made from metal such as steel. However, it should be appreciated that other types of handlebars such as two-piece handlebars (e.g., “clip-ons”) may also be used in accordance with the present invention. 
   As shown in  FIG. 2 , a throttle position sensor  30  is adapted to be coupled to a throttle grip mounted on the right end of the handlebar  26 . Throttle position sensor  30  includes a hollow tube  32 , the details of which are also shown in  FIGS. 3-5 . The tube  32  may be formed of any suitable high-strength material, such as steel, for example only. The tube  32  includes the first end  34  and an opposed second end  40 . The first end  34  is defined by a shoulder  38  forming a reduced diameter collar  36  at the first end  34 . The shoulder  38  and collar  36  are adapted for receiving a spacer  50  as described hereafter and shown in  FIG. 4 . The first end  40  of the tube  32  is formed with opposed recesses defined by an outer opening  42 , a circumferentially extending shoulder  44  and an inner notch defined by inward tapering sides  46  and an inner end  48 . The notches form a mount for a stop  104  as described hereafter. 
   The spacer  50 , as shown in detail in  FIG. 4 , has a hollow bore  56  having an enlarged diameter end flange  54 . A bore  56  extends through the spacer  50  for receiving conductors. 
   Referring now to  FIGS. 6 and 7 , there is depicted a sensor assembly including a circuit board, such as a printed circuit board  62  which contains surface mount components, not shown. 
   A Hall-effect sensor  72  mounted within a sealed housing  70  has conductors extending therefrom to terminations on the printed circuit board  62 . As is understood in the art, the Hall-effect sensor  72  is configured to output a voltage proportional to the sensor&#39;s movement or orientation in a magnetic field. By example, the Hall-effect sensor  72  includes a small semi-conductive platelet and evaluation circuitry integrated into a single silicon chip. As such, the sensor  72  may output a variable voltage, (i.e., 0-5 volts) directly to the printed circuit board  62  to indicate the movement or orientation of the sensor  72  in the magnetic field. 
   The sensor  72  may be a programmable, linear Hall-effect sensor, such as that available from Micronas Semi-Conductor Holding AG of Zurich, Switzerland under Model No. Hal815. 
   Alternately, other types of Hall-effect sensors may be utilized. Further, other types of sensors operable to output a variable voltage dependent upon relative movement or orientation of fixed and moving members may be utilized. 
   Electrical conductors  64  which may be carried in a sheave or flat cable  66  are also connected to terminations on the printed circuit board  62 . The individual wires  64  may also be electrically insulated from each other within the sheave  66 . In the illustrated exemplary construction, the conductor or cable  66  includes three individual wires or conductors  64 . The exposed ends of the individual wires  64  are electrically connected to the printed circuit board  62 . 
   Once the conductors from the Hall-effect sensor  72  and the wires  64  from the cable  66  are assembled to the printed circuit board  62 , the entire assembly is over-molded in a sensor over-mold housing  74 , shown in phantom in  FIG. 6 , to substantially encase the components. 
   As shown in  FIG. 7 , two sensor assemblies  60  are mounted within the tube  32  180° apart. Although only one sensor  60  is required for operation, two identical sensors spaced 180° from each other provide complete independent redundancy. 
   Referring now to  FIGS. 8 ,  9 , and  10 , there is shown the cam housing  80  which includes a first end  82  and an opposed second or cam end  90 . A pair of opposed recesses  84  are formed at the first end  82  to interface with interference with the tube  32  to prevent rotation between the cam housing  80  and the tube  32 . 
   A recess  86  is formed along one surface of the cam housing  80  for receiving and locating one printed circuit board  62  assembly. 
   A bore  88  extends through the entire cam housing  90  for passage of conductors from the end of the throttle as shown hereafter. The conductors from the two sensor assemblies  60  are shown in  FIG. 9  extending outward from the first end  82  of the cam housing  80 . 
   As shown in  FIG. 10 , the second end or cam  90  of the cam housing  80  is formed with at least one pair and, by example, opposed pairs of cam surfaces. The first pair of cam surfaces  92  is formed at a high helix angle for off throttle and cruise-off feel. The second pair of cam surfaces  94  is formed at a lower helix angle for on throttle feel. 
   Referring now to  FIGS. 11-21 , the details of the rotor assembly  100  will be described. The rotor  102  is in the form of an elongated body formed of a suitable material, such as a molded plastic. The body has a first end  120  and an opposed second end  122  with a through bore extending therethrough. A plurality of splines  124  extend between the first end  120  and a recess  125  which is configured for receiving a seal, such as an o-ring seal, to provide a grip to the sensor interface and also terminal mating orientation. 
   An enlarged diameter annular flange  126  is spaced from the first end  120 . A shaft of substantially constant diameter  128  extends from the flange  126  through a conical transition  132  to an end section  134 . A plurality of modified splines  130  are formed along the shank  128  for anti-rotation of a cam follower and axial movement of the cam follower along the rotor  102 . 
   A plurality of keys  129  are formed on the flange  126  for mating interface in only one position. 
   A magnet  110  is an insert molded within the rotor  102  at one end of the shank  128 , by example only. The square cross section of the magnet  110  allows 140° of rotation with a linear output. A plurality of terminals  136 , with three terminals  136 , being depicted by way of example only, are formed within a recessed cavity at the first end  120  of the rotor  102 . The terminals  136  are connected to insulated conductors which extend through the rotor  102  and out from the second end  122 , as shown in  FIG. 12 . The conductors are individually insulated and may be surrounded by a single insulating sheath. The terminals  136  allow connection to additional sensors or switching elements in the throttle assembly, such as heated wire connections, headlights, etc. 
   The stop  104  is mounted on the first end  120  of the rotor  102 . The stop  104  has a first end  142  and an opposed second end. A cylindrical sleeve  140  extends from the first end to the second end. A reduced diameter opening  144  extends through the first end  142  of the sleeve  140  and opens to a larger diameter interior bore within the sleeve  140 . Thrust surfaces  148  and  149  are formed at the second end of the sleeve  140 . Recesses  152  may be formed in each thrust surface  148  and  149  for weight savings. Each thrust surface  148  and  149  has opposed ends  154  and  156  which are spaced above the second end of the sleeve  140 . The exposed second end portions of the sleeve  140  define crimp surfaces for attaching the stop  104  to the tube  32 . Anti-rotation interface members  150  are formed on the exterior surface of the sleeve  140  and extend axially from the thrust surfaces  148  and  149 , as shown in  FIGS. 14 and 15 . The interface surfaces  150  interact with the interface surfaces or keys  129  on the rotor as shown in  FIGS. 17-19  to form stops. An additional pair of full throttle and half-throttle stops  151  and  153  are formed on and extend axially from the first end  142  of the sleeve  140 . The stops  151  and  153  interact as shown in  FIG. 9  during rotation of the throttle relative to the rotor  102  to limit maximum rotation of the throttle. 
   Redundant stop surfaces are shown in  FIGS. 20 and 21  at the ends  129  of the splines  130  intermediate the length of the shaft portion  128  of the rotor  102 . Axial movement of the rotor  102  is limited by engagement of the inner fingers  176  in the cam follower  108  with the ends  129  of the splines  130 . 
   Referring now to  FIGS. 24A and 24B  and  FIGS. 25A-27C , there is depicted the interface between the rotor  102 , the cam follower  108 , and the cam surfaces  90  on the cam housing  80 . The cam follower  108  is formed of a body having a first end  175  and an opposed second cam follower end  177 . The first end  175 , as shown in  FIG. 25B , has a plurality of radially inward extending enlargements  176  which ride within the rotor splines  130 . Recesses  178  in the bore straddle the splines  130 . 
   As shown in  FIG. 24A , the second or cam surface end of the cam follower  108  is formed with a pair of identical cam surfaces  170  which has the same high helix angle for off throttle or cruise-off feel. A second pair of cam surfaces  172  is also formed on the cam follower  108  and has the same length and same lower helix angle as the cam surfaces on the cam follower  80  for on throttle feel. 
   The cam follower  108 , as shown in  FIGS. 24A and 24B  rides along the splines  130  on the rotor  102  and compresses the spring  106  upon axial movement in one direction. The teeth on the cam follower  108  will bottom out at the ends  129  of the splines  130  if the primary stop fails thereby forming a redundant stop to control maximum throttle open position. Release of the rotative force on the throttle enables the spring  106  to move the cam follower  108  back along the spline  130  on the rotor rotating the throttle back to the idled position. This is shown in greater detail in  FIGS. 27A ,  27 B, and  27 C. 
   The throttle  200  is shown in  FIGS. 28 and 29 . The throttle  200  includes apertures for receiving fingers or tabs on an end cap  202  to enable the end cap  202  to snap into and close off the end of the throttle  200 . As shown by way of example in  FIG. 29 , a terminal  204  may be mounted within the end of throttle for receiving an electrical pin connection to one of the terminals in the rotor  102  to provide a heated grip termination. The seal  127 , such as an O-ring seal, is mounted in the recessed groove in the rotor  102  and engages an inner surface of a collar  210  and the throttle  200  as shown in  FIG. 30 . The seal  127  compensates for any gap between the outside diameter of the tube  32  and the inside diameter of the handle bar. The seal  127  may also reduce the amount of vibration transferred from the handlebar to the throttle position sensor. Alternately, a plurality of resilient members or tabs, not shown, may extend from the outer surface of the tube  32  to engage the inner surface of the handle bar in order to compensate for any gap between the outside diameter of the tube  32  and the inside diameter of the handlebar. 
   It may also be possible to form the inside diameter of the handlebar to be snugly received within the tube  32  without the use of the o-ring  127  or resilient members. 
   The throttle grip, which may include a rubber or resilient gripping surface to be grasped by the rider of the motorcycle, is axially retained on the handlebar by the end cap  202 . The throttle grip is angularly oriented with respect to the splines  130  on the rotor  102  to allow for relative adjustments in small increments according to the pitch of the splines. 
   During operation of the motorcycle  10 , the operator may twist the throttle grip  38  to provide a throttle angle input to the throttle position sensor  46 . The throttle position sensor  46 , in turn, is configured to output a signal that is proportional to the throttle angle input to the ECU. In a motorcycle  10  incorporating a fuel injection system and a cable-actuated throttle, the ECU may utilize the signal to calculate how much fuel should be added to the air entering the engine  22 . After calculating how much fuel should be added, the ECU may control one or more fuel injectors (not shown) to add the requisite amount of fuel. In a motorcycle  10  incorporating a drive-by-wire system, the signal output by the throttle position sensor  46  may also be used by the ECU to control the throttle opening. 
   With reference to  FIG. 4 , the throttle position sensor  46  is shown in a configuration corresponding to zero throttle angle input. In other words, the throttle opening is substantially closed. However, a sufficient amount of air is allowed through the throttle opening to allow the engine  22  to idle at a low speed. At zero throttle angle input, the throttle position sensor  46  may output a small voltage (e.g., less than 1 volt) to the ECU so the ECU may control the one or more fuel injectors to add the appropriate amount of fuel to maintain the engine  22  at idle speed. 
   Without any input from the rider of the motorcycle  10 , the throttle grip  38  and the throttle position sensor is biased to zero throttle angle input by the engagement of the respective cam surfaces  170 ,  122  of the cam  154  and the housing  110 . As shown in  FIG. 4 , the spring  158  biases the cam  154  against the housing  110 . Due to the contours of the respective cam surfaces  170 ,  122  of the cam  154  and housing  110 , an axial force on the cam  154 , such as that provided by the spring  158 , causes the cam  154  to rotate about the central axis  54  relative to the housing  110  until the respective stop surfaces  174 ,  126  of the cam  154  and housing  110  abut. The rotor  50  is forced to rotate with the cam  154  because the cam  154  is splined for co-rotation with the rotor  50 . 
   With reference to  FIG. 6 , the orientation of the magnet  78  is shown relative to the Hall-effect sensors  146  during zero throttle angle input. The magnet  78  emits a magnetic field, represented by field lines “B.” Due to the orientation of the magnet  78  relative to the Hall-effect sensors  146  during zero throttle angle input, the field lines B do not substantially transversely permeate the Hall-effect sensors  146 . As a result, the Hall-effect sensors  146  may output a small voltage (e.g., less than 1 volt) to the ECU so the ECU may control the one or more fuel injectors to add the appropriate amount of fuel to maintain the engine  22  at idle speed. 
   When the rider of the motorcycle  10  desires to accelerate the motorcycle  10 , a throttle angle input is provided to the throttle position sensor  46 . Due to the engagement of the splines  250 ,  102  on the throttle grip  38  and the rotor  50 , the rotor  50  rotates relative to the housing  110 .  FIG. 5  illustrates the rotor  50  in a position corresponding with full throttle angle input. Since the cam  154  is splined for co-rotation with the rotor  50 , the cam  154  also rotates relative to the housing  110 . Rotation of the cam  154  relative to the housing  110  causes sliding contact between the respective cam surfaces  170 ,  122  of the cam  154  and the housing  110 , and the contours of the respective cam surfaces  170 ,  122  cause the cam  154  to slide along the rotor  50  away from the housing  110 , against the bias of the spring  158 . When the rider of the motorcycle  10  releases the throttle grip  38 , the spring  158  biases the cam  154  toward the housing  110 . The respective cam surfaces  170 ,  122  of the cam  154  and the housing  110 , therefore, cause the cam  154  and the rotor  50  to rotate relative to the housing  110  as the cam  154  along the rotor  50 . The throttle position sensor  46  is returned to zero throttle angle input when the respective stop surfaces  174 ,  126  of the cam  154  and the housing  110  abut. 
   With reference to  FIG. 7 , the orientation of the magnet  78  is shown relative to the Hall-effect sensors  146  during full throttle angle input. In this orientation of the magnet  78 , the field lines B substantially transversely permeate the Hall-effect sensors  146 . As a result, the Hall-effect sensors  146  may output a relatively large voltage (e.g., between about 4 and 5 volts) to the ECU so the ECU may control the one or more fuel injectors to add the appropriate amount of fuel to the air passing through the throttle opening. 
   In the illustrated construction of the throttle position sensor  46 , two sensor assemblies  118  are utilized. Incorporating two sensor assemblies  118  in the throttle position sensor  46  provides double redundancy to the fuel injection system. Specifically, one of the Hall-effect sensors  146  sweeps in a positive voltage direction (e.g., between 0 and 5 volts) and the other Hall-effect sensor  146  sweeps in a negative voltage direction (e.g., between −5 and 0 volts). In this manner, the sensors  146  self-check to ensure that the throttle angle input signal received by the ECU is continuous and that the quality of the throttle angle input signal received by the ECU is within specifications.