Abstract:
A starter includes: a gear housing mounted near an engine to be started; a speed reducing gear assembly within the gear housing; an output member aligned with a movable portion of the engine and rotatable under the influence of the gear assembly to move the movable portion to initiate operation of the engine; a motor housing mounted to the gear housing; and a fluid-driven motor within the motor housing and including a motor shaft rotating at a first speed to drive rotation of the speed reducing gear assembly, such that the output member is driven at a second speed lower than the first speed. The motor housing and motor are serviceable without changing the alignment of the output member relative to the movable portion of the engine.

Description:
FIELD 
   The invention relates to starters for engines, and more particularly, to starters that are serviceable while mounted to the engine. 
   BACKGROUND 
   Internal combustion engines are typically provided with starter systems for initiating operation of the engine. Starter systems usually include an air motor driven by pressurized air and a gear system. Pressurized air is introduced to the air motor, causing a rotor to rotate. The rotor, which has a higher number of revolutions per minute (rpm) than what is needed to start the engine, is connected to the gear system, which includes one or more speed reducing gears configured to match the air motor rpm to the engine rpm. The reducing gears drive an output device such as a pinion, which is coupled to the engine. Rotation of the pinion cranks the engine, initiating operation of the engine. 
   SUMMARY 
   In one embodiment, the invention provides a starter comprising: a gear housing mounted near an engine to be started; a gear assembly within the gear housing; an output member aligned with a movable portion of the engine and rotatable under the influence of the gear assembly to move the movable portion to initiate operation of the engine; a motor housing mounted to the gear housing; and a fluid-driven motor within the motor housing and including a motor shaft driving rotation of the gear assembly; wherein the motor housing and motor are serviceable without changing the alignment of the output member relative to the movable portion of the engine. 
   In another embodiment, the invention provides a starter for moving a movable portion of an engine to start the engine. The starter comprises a gear housing having first and second opposite ends; a gear assembly within the gear housing and including a plurality of speed-reducing gears; an output member at the first end of the gear assembly aligned with the movable portion of the engine and adapted to operably couple to the movable portion of the engine; a motor housing having a first end mounted to the second end of the gear housing and a second end opposite the first end, the second end defining a service aperture; a motive fluid inlet adapted to permit a flow of motive fluid into the motor housing; a rotor rotatably mounted within the motor housing; and a motive fluid outlet mounted to the second end of the motor housing over the service aperture, and adapted to exhaust the motive fluid to a desired destination after the motive fluid has flown through the motor housing. The rotor rotates at a first speed in response to the flow of motive fluid through the housing. The speed-reducing gears rotate in response to rotation of the rotor. The output member rotates at a second speed slower than the first speed in response to rotation of the speed-reducing gears to cause the movable portion of the engine to move and start the engine. The motive fluid outlet is removable from the second end of the motor housing without changing the alignment of the output member relative to the engine. The rotor is removable from the motor housing through the service aperture after the motive fluid outlet has been removed and without disengaging the gear housing from the engine. 
   In another embodiment, the invention provides a method of servicing an engine starter that is engaged with an engine to be started. The engine starter has a gear housing mounted near the engine, a speed reducing gear assembly within the gear housing, an output member aligned with a movable portion of the engine and adapted to operably couple with the movable portion and rotatable under the influence of the gear assembly to move the movable portion to initiate operation of the engine, a motor housing mounted to the gear housing, a fluid-driven motor within the motor housing and including a motor shaft driving rotation of the speed reducing gear assembly to drive the output member, and a motive fluid outlet mounted over a service aperture of the motor housing and adapted to exhaust a motive fluid to a desired destination. The method comprises: removing the motive fluid outlet from the motor housing without changing the alignment of the output member relative to the engine; and then servicing the fluid-driven motor through the service aperture; and then installing the motive fluid outlet over the service aperture to resume operation of the engine starter. 
   Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a starter system according to one embodiment of the invention. 
       FIG. 2  is a cross-sectional view of the starter system of  FIG. 1 . 
       FIG. 3  is an exploded view of the starter system of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   Before any embodiments of the invention are explained in detail, it is to be understood that the invention 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 invention is capable of other embodiments 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,” or “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. 
     FIGS. 1-3  illustrate a starter system  100  according to one embodiment of the invention. Starter system  100  can couple to an engine  101  ( FIG. 2 ) for providing start-up cranking of the engine  101 . Starter system  100  can be used with any type of engine, including but not limited to, internal combustion engines, diesel engines, and turbine and microturbine engines. 
   Starter system  100  can include an air motor module  102 , a gear module  104  and motive fluid outlet  106 . The gear module  104  is at the front of the starter system  100  oriented towards the engine  101  while the motive fluid outlet  106  is at the rear of the starter system  100  away from the engine  101 . The air motor module  102  can include an air motor housing  108  with a motive fluid inlet  110  for receiving a motive fluid, such as pressurized air, into the air motor housing  108 , and a service aperture  112  at one end of the housing  108 . The air motor housing  108  can define an air motor chamber  114  in fluid communication with the motive fluid inlet  110  via a channel  116 . 
   With reference to  FIGS. 2 and 3 , the air motor module  102  can further include a rotor  122 , a stator  124 , a stator housing  128  and a containment ring  130  arranged along the longitudinal axis  125 . As shown in  FIG. 3 , the stator  124  can be secured to the containment ring  128  against rotation by way of fasteners  129 . The stator  124  can direct the flow of motive fluid against the rotor  122  to cause rotation of the rotor  122  with respect to the stator  124 . In one example, the motive fluid may be provided in the range of 30-150 psig, the stator  124  may act as a supersonic nozzle, and the rotor  122  may be designed to have a free turbine or “run away” speed of 65,000 rpm. The rotor  122  can be interconnected with the gear module  104  via, for example, an air motor shaft  134 . The air motor shaft  134  is supported for rotation by bearings in the motor housing  108 . 
   With reference again to  FIG. 2 , the gear module  104  can include one or more speed reducing gears  136  and a planetary gear  137  within a gear housing  138 . Mounted at opposite ends of the reducing gears  136  and the planetary gear  137  are the air motor shaft  134  and an output member  140 . The reducing gears  136  and the planetary gear  137  cause rotation of the output member  140  in response to rotation of the air motor shaft  134 , while reducing speed and increasing torque of the output member  140  compared to the air motor shaft  134 . In other embodiments, however, the reducing gears  136  and/or the planetary gear  137  may be excluded from the starter system  100 . As shown in  FIG. 2 , the gear housing  136  is offset from the longitudinal axis  125  so that the output member  140  is offset from the longitudinal axis  125 . In other embodiments, however, the gear housing  136  and/or the output member  140  is arranged along the longitudinal axis  125  as well. 
   The output member  140  can be, for example, a pinion. The output member  140  can interface (e.g., through direct meshing with a gear, or through a belt, a chain, a plurality of gears, or any other suitable means for transferring rotation and torque) with a movable portion, mechanism, or member  141  of the engine  101  and can be operable to move the movable portion  141  of the engine  101  in response to rotation of the reducing gears  136  in the gear housing  138 . The movable portion  141  of the engine  101  may include, for example, a crankshaft, a gear or other torque transfer member, and other movable parts. The rotor  122  rotates at a first speed in response to the flow of motive fluid through the channel  116  and chamber  114  of the motor housing  108 . The planetary gear  137  rotates in response to rotation of the rotor  122  and drives the speed-reducing gears  136 . The output member  140  rotates at a second speed slower than the first speed in response to rotation of the speed-reducing gears  136  to cause the movable portion  141  of the engine  101  to move and start the engine  101 . 
   In cases where the movable engine portion  141  is rotatable, the output member  140  can be said to transfer torque from the starter system  100  to the engine  101 . This movement of the movable portion  141  of the engine  101  by the output member  140  can effectively start the engine  101 . The gear housing  138  can include a flange  142  at an end opposite the air motor shaft  134 . The flange  142  facilitates mounting the gear module  104  to the engine  101  or near the engine  101  to engage the output member  140  with the movable portion  141  of the engine  101 . 
   The motive fluid outlet  106  can provide an exhaust system for the motive fluid from the starter system  100 . The motive fluid outlet  106  can direct the flow of motive fluid out of the air motor housing  108  after the motive fluid has flown past the rotor  122 . The motive fluid outlet  106  can include an exhaust cap  143  mounted to the air motor housing  108  over the service aperture  112 . Thus, the output member  140  and mounting flange  142  are at a first end of the gear housing  138 , a second end of the gear housing  138  (opposite the first end) is mounted to a first end of the motor housing  108 , a second end of the motor housing  108  (opposite the first end) defines the service aperture  112  and has mounted thereon the exhaust cap  143 . 
   A debris screen  144  can be positioned between the air motor housing  108  and the exhaust cap  143  for trapping debris. An O-ring seal  146  can also be positioned between the air motor housing  108  and the exhaust cap  143  to prevent motive fluid leakage. The exhaust cap  143 , debris screen  144  and O-ring seal  146  can be arranged along the longitudinal axis  125  as well. 
   The motive fluid outlet  106  can further include a conduit  148  for directing exhaust motive fluid away from the starter system  100 . The conduit  148  can be, for example, an elbow. The conduit  148  can include a pipe flange  150  for mounting the conduit  148  to a pipe coupling  152  to facilitate securing the conduit  148  to a pipe or other structure for directing the exhaust motive fluid to a remote location. The elbow version of the conduit  148  illustrated in the drawings may be employed in applications that use natural gas or another combustible gaseous fuel as the motive fluid, as for example, at a site that has a ready supply of such fuel for the engine  101  or another device. The pipe to which the conduit  148  is secured through the pipe coupling  152  may direct the natural gas or other combustible gaseous fuel to a flare or the combustion chamber of another device for immediate combustion, or may recapture the natural gas or other combustible gaseous fuel for future use. 
   In alternate embodiments of the motive fluid outlet  106 , the conduit  148  may be replaced with a diffuser mounted to the exhaust cap  143 . The diffuser would lower the pressure of the motive fluid prior to venting the motive fluid to the atmosphere or ambient surroundings. Such diffuser may be particularly useful in applications using compressed air as the motive fluid. The term “desired destination” is used herein to refer to the atmosphere, conduits, flares, combustion chambers, or any other destination for the motive fluid upon flowing out of the motive fluid outlet  106 . 
   As shown in  FIG. 3 , four elongated fasteners  154  can extend from the gear housing  138 . The fasteners  154  can be arranged parallel to the longitudinal axis  125 . The air motor housing  108  can include four complementary passages  156  sized and shaped for receiving the fasteners  154 . The fasteners  154 , when received in the passages  156 , can extend substantially the entire length of the air motor housing  108 . Mating fasteners  158  can be placed over the fasteners  154  to secure the air motor module  102  to the gear module  104 . The fasteners  154  and the mating fasteners  158  can be, for example, threaded fasteners such as bolts or studs and nuts. 
   The exhaust cap  143  can also include four passages  160  for receiving the fasteners  154  so as to mount the motive fluid outlet  106  to the air motor module  102 . That is, the fasteners  154  can extend through the passages  156  and the passages  160  with the mating fasteners  158  placed over the fasteners  154  at the exhaust cap  143 . Therefore, a single set of fasteners  154  can be used to mount the motive fluid outlet  106  and the air motor module  102  to the gear module  104 . In this regard, the fasteners  154  extend through the motor housing  108  and secure the motor housing  108  to the gear housing  138  at one end of the motor housing  108 , and secure the motive fluid outlet  106  to the motor housing  108  at an opposite end of the motor housing  108 . In alternate embodiments, however, separate fasteners may be employed to mount the motive fluid outlet  106  to the air motor module  102 . 
   Access to the air motor module  102  can be accomplished by removing the mating fasteners  158  from the fasteners  154 . The exhaust cap  143  can be slid off of the fasteners  154  to remove the motive fluid outlet  106  from the air motor module  102 , exposing the service aperture  112 . Then, each internal component of the air motor module  102  can be slid out of the air motor housing  108  in turn. For example, the debris screen  144 , the rotor  122 , the stator  124 , the stator housing  128  and the containment ring  130  can be removed from the air motor housing  108  through the service aperture  112 . The air motor housing  108  can also be removed by sliding the air motor housing  108  off of the fasteners  154 . 
   Alternately, the entire air motor module  102  can be removed with internal components substantially in their operative positions within the housing  108 , by sliding the air motor housing  108  off of the four fasteners  154  with the internal components inside of the air motor housing  108 . Alternately, the air motor module  102  may be serviced (e.g., cleaned or parts replaced) while still within the motor housing  108 . As used herein, references to servicing the components of the starter “through the service aperture” include removing the components through the service aperture  112  prior to service, or leaving the components in the motor housing  108  while servicing the components. 
   Throughout the dismounting or disassembling process, the gear module  104 , including the flange  142 , the gear housing  138 , the reducing gears  136  and the planetary gear  137 , can remain in position aligned with the engine  101  through the flange  142 . Likewise, throughout this process, the output member  140  can remain aligned with the movable portion  141  of the engine  101 . This provides a substantial advantage in terms of the time required to service the air motor module  102  in the event foreign debris becomes entrained in the motive fluid and interferes with operation of the starter system  100  or occludes the screen  144  between scheduled maintenance. The present invention permits the rear portion of the starter  100  to be removed so the parts of the air motor module  102  can be cleaned, replaced, or otherwise serviced without affecting the relatively precise alignment of the output member  140  with respect to the movable portion  141  of the engine  101  and without having to disengage the output member  140  from the engine  101 . As used herein, “disengage” means to operably decouple the output member  140  from the movable portion  141  of the engine  101  to the extent that the output member  140  cannot transmit sufficient torque or other force to the movable member  141  of the engine  101  to start the engine  101 . 
   To re-assemble the starter system  100 , the process is reversed. That is, the air motor housing  108  is installed on the gear module  104  by sliding the air motor housing  108  back over the fasteners  154 . The internal components of the air motor module  102  can be assembled within the air motor chamber  108  prior to installing the air motor housing  108  on the gear module  104 . Alternately, the internal components of the air motor module  102 , including, for example, the rotor  122  and the stator  124 , can be installed in the air motor housing  108  after the air motor housing  108  is slid onto the fasteners  154  by passing them through the service aperture  112 . After the air motor module  102  is in place on the fasteners  154 , the exhaust cap  143  is slid over the ends of the fasteners  154  to install or mount the motive fluid outlet  106  onto the air motor module  102 . Finally, the mating fasteners  158  are secured to the fasteners  154 . 
   The starter system  100  can be configured so that the motive fluid outlet  106  can be removed from the air motor module  102  to permit access to the service aperture  112  at the rear of the starter system  100  without removing the air motor module  102  from the gear module  104  and without changing the alignment of the gear module  104  relative to the engine  101 . The starter system  100  can also be configured so that the internal components of the air motor module  102 , including, for example, the rotor  122  and the stator  124 , can be removed from the air motor housing  108  through the service aperture  112  while the motive fluid outlet  106  is removed without removing the air motor housing  108  from the gear module  104 . Finally, the starter system  100  can also be configured so that the air motor housing  108  and/or the entire air motor module  102  can be removed from the gear module  104  without changing the alignment of the gear module  104  relative to the engine  101 . 
   Thus, the invention provides, among other things, an engine starter that is serviceable without being removed or disengaged from the engine. Various features and advantages of the invention are set forth in the following claims.