Patent Publication Number: US-8522631-B2

Title: Engine starter mechanism using one way clutch

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an engine starter mechanism using a one way clutch for use in a vehicle or the like. 
     2. Description of the Related Art 
     Usually in an engine starter mechanism using a one way clutch, a starter motor is constantly meshed with a ring gear to transmit, through the one way clutch, a rotating force of the starter motor from the ring gear connected to an outer race of the one way clutch to a crank shaft of an engine (connected to an inner race of the one way clutch), thereby starting the engine. After the start of the engine, the crank shaft overruns, and is synchronized with rotation of the engine, whereby the ring gear is stopped. 
     The one way clutch has a function of preventing the starter motor from being driven at an excessively high speed after the start of the engine. 
     In the engine starter mechanism using the conventional one way clutch, the outer race of the one way clutch which transmits a driving force from the starter motor to the crank shaft of the engine includes a flange portion which extends in an axial direction. This constitution includes an oil seal interposed between this flange portion and the inner race of the one way clutch. 
     However, the flange portion extending in the axial direction is disposed so as to acquire a space where the oil seal is interposed, and hence a length of the engine starter mechanism in the axial direction cannot be shortened, which has caused problems in space saving and cost reduction. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide an engine starter mechanism using a one way clutch in which a length of the engine starter mechanism in an axial direction is shortened, whereby space saving and cost reduction can be achieved. 
     To achieve the above object, according to the present invention, there is provided an engine starter mechanism using a one way clutch, comprising: a starter motor; a ring gear for receiving a driving force from the starter motor; the one way clutch including an outer race, an inner race disposed away from the outer race in a radially inner direction and relatively rotatably disposed concentrically with the outer race, and a torque transmitting section disposed between the outer race and the inner race to transmit a torque; and an oil seal for sealing the one way clutch, wherein the ring gear is connected to the outer race of the one way clutch, and the oil seal is held between the ring gear and the outer race. 
     According to the present invention, an effect can be obtained as follows. There can be provided an engine starter mechanism using a compact one way clutch which can shorten a length of the engine starter mechanism in an axial direction and which is excellent in space saving and cost performance. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The FIGURE is an axially partially sectional view of an engine starter mechanism using a one way clutch showing an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENT 
     A preferred embodiment of the present invention will now be described in detail in accordance with the accompanying drawing. 
     Hereinafter, the present invention will be described in detail with reference to the drawing. It is to be noted that needless to say, an embodiment described hereinafter will be explained as an illustration of the present invention, and does not limit the present invention. 
     The FIGURE is an axially partially sectional view of an engine starter mechanism using a one way clutch showing an embodiment of the present invention. As shown in the FIGURE, an engine starter mechanism  50  using a one way clutch  20  includes a starter motor  1  which is an electromotive motor to be driven by a power supplied from a power source (not shown), a ring gear  6  which receives a driving force from the starter motor  1 , the one way clutch  20 , and an oil seal  12  which seals the one way clutch  20 . 
     The ring gear  6  includes a gear portion  4  constantly meshed with a gear  3  fixed to a rotary shaft  2  of the starter motor  1 , and a plate portion  5  to which the gear portion  4  is fixed. Between the ring gear  6  and a crank shaft  13  of an engine (not shown), the one way clutch  20  is disposed. The one way clutch  20  includes an outer race  21 , an inner race  22  disposed away from the outer race  21  in a radially inner direction and relatively rotatably disposed concentrically with the outer race, and a torque transmitting section disposed between the outer race  21  and the inner race  22  to transmit a torque. 
     The outer race  21  integrally includes a flange portion  33  disposed at one end in an axial direction and extending in a radially outer direction. On a radially inner side of the outer race  21 , the inner race  22  is disposed. Between the outer race  21  and the inner race  22 , there is disposed the torque transmitting section including a plurality of sprags  23  which are torque transmission members engaged with the inner and outer races to transmit the torque between the inner race and the outer race, an outer holder  24  and an inner holder  25  which hold the sprags  23 , and a ribbon spring  26  which applies a rising moment to the sprags  23 . 
     On a radially inner side of the inner race  22 , a radially inner flange portion  35  is disposed, and fixed to the crank shaft  13  of the engine by a bolt  36 . Moreover, on a radially outer side of the inner race  22 , a radially outer flange portion  28  is disposed, and the radially outer flange portion  28  becomes an inner race of a bearing  9 . The radially inner flange portion  35  and the radially outer flange portion  28  are disposed integrally with the inner race  22 . A fly wheel  40  is fixed to the crank shaft  13 . 
     An outer race  27  of the bearing  9  disposed by the one way clutch  20  fits into a stepped portion  34  of the outer race  21  of the one way clutch  20 . The bearing  9  is incorporated in the one way clutch  20 . Therefore, a length of the engine starter mechanism  50  in the axial direction is shortened, and space saving can be realized. 
     The flange portion  33  of the outer race  21  of the one way clutch  20  is connected to the plate portion of the ring gear  6  through a rivet  7 . At this time, a radially outer portion  8  of the oil seal  12  disposed adjacent to the bearing  9  is held between the plate portion  5  and the outer race  21  and between the plate portion  5  and an axial end face  31  of the outer race  27  of the bearing  9 . Therefore, a space for the oil seal  12  can be minimized, and hence the length of the engine starter mechanism  50  in the axial direction is further shortened as compared with a conventional mechanism, whereby the space saving can be realized. Moreover, any additional member for fixing the oil seal  12  is not necessary, which can decrease the number of parts and save cost. 
     On a side of the one way clutch  20  opposite to the oil seal  12  in the axial direction, a member  37  which forms a passage of a lubricant is disposed, to form an oil path  38  through which the lubricant is supplied. The lubricant is supplied to the oil path  38  by an oil pump (not shown), thereby lubricating the one way clutch  20  and the bearing  9  through the oil path  38 . 
     The lubricant supplied through the oil path  38  passes through a through hole  10  disposed in the inner race  22  of the one way clutch  20 , to flow into a sealed space  39  defined by the oil seal  12  and the bearing  9 , thereby lubricating the bearing  9 . On the other hand, the oil path  38  extends in a radially outer direction so as to lubricate the one way clutch  20 , and is sealed with a second oil seal  32  disposed between the member  37  and the outer race  21  of the one way clutch  20 . 
     In the vicinity of the through hole  10  of the inner race  22  of the one way clutch  20 , a recess portion  11  is disposed, and in the recess portion  11 , a lip portion  30  of the oil seal  12  is contained. In consequence, the space saving in the axial direction can be realized. 
     The outer race  27  of the bearing  9  faces a clutch portion of the one way clutch  20  in the axial direction. In consequence, the outer race  27  performs a function of a stopper in the axial direction, whereby the clutch portion of the one way clutch  20  is prevented from dropping down in the axial direction. 
     The engine starter mechanism having the above constitution operates as follows. The starter motor  1  is constantly meshed with the gear portion  4  of the ring gear  6 . In this state, when the starter motor  1  is driven by a driving source (not shown), a rotating force of the motor is transmitted to the outer race  21  of the one way clutch  20  through the gear  3  meshed with the gear portion  4 . 
     The driving force from the outer race  21  is transmitted to the inner race  22  through the clutch portion, and transmitted to the crank shaft  13  fixed to the inner race  22 . In consequence, the engine is started. After the start of the engine, the crank shaft  13  overruns, and is synchronized with rotation of the engine, whereby the one way clutch  20  idles, and the ring gear  6  is stopped. Therefore, after the start of the engine, the starter motor is prevented from being driven at an excessively high speed. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2010-095688, filed Apr. 19, 2010, which is hereby incorporated by reference herein in its entirety.