PATENT ABSTRACT
Configuration for waterproofing rotary mechanism shafts protruding from the compartments in which they are housed in a spinning reel main unit. In each case the shafts are supported on ball bearings, but in some cases the outer race and its mounting are fitted to be stationary in the compartment with respect to the compartment, and the shaft and the inner race supporting are rotatable. In other cases, the shaft and the inner race supporting it are stationary, and the outer race and its mounting in the compartment rotate about the shaft. Shaft seals are furnished to seal respective protruding shafts. In all cases, the seal is retained by the compartment mounting axially outward with respect to the compartment and contacts both the stationary and at least either the rotary component or the rotary mechanism shaft. Washers, caps, or lids retain and position the shaft seals against the shaft bearing stationary components.

PATENT DESCRIPTION
BACKGROUND OF THE INVENTION 
     A. Field of the Invention 
     The present invention relates to a water-proof structure, more specifically the present invention relates to a spinning reel having a water-proof structure that prevents liquid from entering a reel main body of the spinning reel. 
     B. Description of the Background Art 
     A spinning reel generally includes a reel main body having a complex combination of mechanisms disposed therein. A rotor is disposed at a front portion of the reel main body and is rotatably supported by the reel main body. A spool is supported on the reel main body, with portions of the rotor extending radially outwardly from the spool such that a fishline may be wound by movement of the rotor around a fishline receiving portion of the spool. The spool is disposed on a front portion of the rotor and supported by the reel main body such that the spool may undergo oscillations back and forth along an axis of rotation of the rotor. A handle is rotatably supported on a side of the reel main body. Within the reel main body are the following: a rotation transmission mechanism for rotating the rotor about the spool, an oscillating mechanism for causing the spool to oscillate along the rotor&#39;s axis of rotation, and a control device that prevents reverse rotation of the rotor. 
     The rotation transmission mechanism includes a master gear shaft, a master gear fixed to the master gear shaft, and a pinion gear. The master gear shaft is supported in the reel main body and extends laterally between opposite sides of the reel main body (left and right sides of the reel main body). The master gear is disposed within the reel main body. The pinion gear has gear teeth engaged with corresponding gear teeth formed on the master gear. The rotor is fixedly coupled to an end of the pinion gear for rotation therewith. 
     The oscillating mechanism includes, for instance, an intermediate gear, a threaded shaft, a slider, and a sliding guide. The intermediate gear is coupled with the pinion gear for rotation in response to rotation of the pinion gear. The threaded shaft is disposed parallel to a spool shaft, with the intermediate gear coupled to one end thereof. The slider is engaged with the threaded shaft via the sliding guide such that the slider moves in response to rotation of the threaded shaft. The spool shaft is axially coupled to the slider such that the spool shaft oscillates back and forth with the slider. 
     Grease is applied to each of the above mentioned moving members to reduce friction, whereby members move more efficiently. 
     The reverse rotation prevention mechanism is located toward a front portion of the reel main body. One end of the spool shaft and an end of the pinion gear extend out of the front of the reel main body through a bore in the reel main body such that the spool and the rotor may be supported thereon, respectively. Ends of the master gear shaft extend out of bores in the opposite sides of the reel main body such that the handle may be attached to the master gear shaft from either of the two opposite ends of the master gear shaft. 
     As described above, many moveable members such as the spool shaft, the master gear shaft, and the pinion gear extend out from the reel main body through bores. The bores are formed such that there are gaps between the bores and the moveable members that pass through the bores to allow smooth movement of the moveable members. There are also gaps between the reel main body and stationary members such as the reverse rotation prevention mechanism. 
     It is possible for liquid such as water to enter the reel main body through the gaps between the bores and the moveable members, and between the stationary members and the reel main body. When the reel main body is being cleaned, it is also possible for water and/or detergent to enter the reel main body. The grease applied to the conventional moveable members has been relatively highly viscous and durable and usually continues to provide lubrication even when liquid enters inside the reel main body from the gaps. 
     PROBLEM TO BE SOLVED BY THE INVENTION 
     Since highly viscous and durable grease is applied to rotation transmission mechanisms and oscillating mechanisms of conventional spinning reels, it is difficult to improve the efficiency in rotating the handle because of the resistance of the grease. Specifically, it is difficult to reduce the amount of energy necessary to rotate the handle in part because of the viscosity of the grease. Also, once seawater that entered inside the reel main body dries, deposits such as crystals of salts remain. When the deposits are trapped between gears or between rollers of a bearing, smoothness of rotation is affected. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to improve the efficiency in rotary action of a handle of a spinning reel while maintaining smoothness of rotation. 
     In accordance with one aspect of the present invention, a water-proof spinning reel prevents liquid from entering an interior space thereof. The interior space is defined with a reel main body of the spinning reel. The water-proof spinning reel includes a moveable member that extends outward from within the reel main body. A stationary member is fixed to the reel main body. A seal member is disposed about the movable member contacting the moveable member and at least one of the reel main body and the stationary member. 
     Preferably, the seal member is made of an elastic material. 
     Preferably, the moveable member is a master gear shaft of the spinning reel. A pair of bearings support opposite ends of the master gear shaft within the reel main body. A pair of the seal members are supported on the reel main body, the seal members being disposed adjacent to respective ones of the pair of bearings on opposite sides of the reel main body such that the seal members each contact respective portions of the master gear shaft, the reel main body, and respective ones of the bearings. 
     Preferably, each of the bearings is a rotary bearing having an outer race coupled to the reel main body, an inner race supporting the master gear shaft, and a roller supported between the outer race and the inner race for rolling therebetween. 
     Preferably, the seal member has an outer diameter that is slightly smaller than an outer diameter of the outer race. 
     Preferably, the master gear shaft is formed with a pair of seal contacting portions that contact respective ones of the seal members, the seal contacting portions having an outer diameter that is smaller than an inner diameter of the inner race. 
     Preferably, the master gear shaft is formed with a hollow interior having a first threaded portion and a second threaded portion, the first threaded portion being a right handed thread and the second threaded portion having a left handed thread. The spinning reel includes a handle assembly that includes a shaft having a first threaded portion and a second threaded portion. The first threaded portion of the master gear shaft is a right handed thread and the second threaded portion of the master gear shaft has a left handed thread. The first threaded portion of the master gear shaft is engageable with the first threaded portion of the handle assembly, and the second threaded portion of the master gear shaft is engageable with the second threaded portion of the handle assembly. 
     Preferably, one of the seal members is disposed between the outer race of the bearing and the reel main body. The other of the seal members is disposed between the other of the outer race and a lid member that is fixed to the reel main body. 
     Preferably, the moveable member is a shaft pivotally supported by the reel main body for controlling a one-way clutch of the spinning reel. The seal member encircles a portion of the shaft and contacts the shaft and the reel main body. 
     Alternatively, the moveable member is a rotor and the stationary member is a reverse rotation prevention mechanism fixedly supported on the reel main body. The seal member is supported between the rotor and the reel main body so as to contact both the rotor and the reel main body. 
     Preferably, a cylindrical elastic member adapted to encircle a flange portion formed at a front side of the reel main body and an outer peripheral surface of the reverse rotation prevention mechanism. 
     In accordance with another aspect of the present invention, a water-proof spinning reel prevents liquid from entering an interior space of a reel main body of the spinning reel. The water-proof spinning reel includes the reel main body and a spool shaft movably supported within the reel main body. A rotor is rotatably supported in the reel main body and a seal member made of an elastic material is disposed between the spool shaft and an end of the rotor contacting the spool shaft and the end of the rotor. 
     In accordance with yet another aspect of the present invention, a water-proof spinning reel for prevents liquid from entering an interior space of a reel main body of the spinning reel. The water-proof spinning reel includes the reel main body, a member adapted for connection to the reel main body and a seal disposed between the reel main body and the member. 
     Preferably, the seal is made of an elastic material. 
     Preferably, the reel main body is formed with a first flange portion that has a semi-cylindrical shape. The member is formed with a second flange portion having semi-cylindrical shape, the first and second flange portions together define a single cylindrical shape. The seal is disposed between contacting surfaces of the first and second flange portions. 
     Preferably, the reel main body is formed with an opening, and the member is a lid adapted to cover the opening, the seal being disposed between contacting surfaces of the member and the reel main body. 
     Preferably, the reel main body is formed with an opening and a first flange portion that has a semi-cylindrical shape. The member is formed with a second flange portion having semi-cylindrical shape, the first and second flange portions together define a single cylindrical shape. The spinning reel further includes a lid adapted to cover the opening, the seal being disposed between contacting surfaces of the member and the reel main body, and the first and second flange portions. 
     In accordance with yet another aspect of the present invention, a water-proof spinning reel for preventing liquid from entering an interior space of a reel main body of the spinning reel. The water-proof spinning reel includes a spool shaft supported within the reel main body, the spool shaft defining a spool axis. The water-proof spinning reel also includes an oscillation movement mechanism for moving the spool axis back and forth along the spool axis. The oscillation movement mechanism is disposed within the reel main body. A portion of the oscillation movement mechanism is supported within bore formed on a rear portion of the reel main body. A seal member disposed on the rear portion of the reel main body prevents water from entering the reel main body via the bore. 
     With the above water-proof structure for a spinning reel, gaps between the moveable members and the reel main body and/or a stationary member attached to the reel main body is sealed with a seal member. Therefore, it is less likely that liquid enters the interior space of the fishing reel through gaps between the moveable member and the reel main body and/or the stationary member. As a result, grease having a lower viscosity can be utilized to lubricate the various elements within the interior space. Accordingly, resistance from the grease is smaller, whereby efficiency in rotation of the handle is improved. Also, since less liquid enters the interior space, there is a reduction in deposits left when liquid dries. Accordingly, there are fewer deposits trapped between gears and between rollers. Therefore, smoothness of rotation of the handle of the spinning reel can be maintained. 
     These and other objects, features, aspects and advantages of the present invention will become more fully apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings where like reference numerals denote corresponding parts throughout. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side plan view of a spinning reel in accordance with one embodiment of the present invention showing a handle assembly attached to right side of a reel main body of the spinning reel; 
     FIG. 2 is a side cross-sectional view of the spinning reel in accordance with the present invention; 
     FIG. 3 is a back side cross-sectional view of the spinning reel depicted in FIG. 1 with the handle assembly attached on a left side of the reel main body; 
     FIG. 4 is a fragmentary perspective, exploded view of the reel main body of the spinning reel depicted in FIG. 1; 
     FIG. 5 is a fragmentary cross-sectional view of a master gear of the spinning reel depicted in FIG. 1 on a slightly enlarged scale; 
     FIG. 6 is a fragmentary, cross sectional side view of a front portion of the spinning reel depicted in FIG. 1 on a slightly enlarged scale; and 
     FIG. 7 is a fragmentary, cross sectional side view of a rear portion of the spinning reel depicted in FIG. 1 on a slightly enlarged scale. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     OVERALL STRUCTURE 
     A spinning reel in accordance with a first embodiment of the present invention is described below with reference to FIGS. 1 and 2. The spinning reel shown in FIGS. 1,  2 ,  3  and  4  is, relative to most spinning reels, a large spinning reel that is able to hold about 200 m of size 8 fishline, with the fishline wound about a spool  4 , described in greater detail below. The spinning reel includes a reel main body  2 , a rotor  3  that is supported on the reel main body  2  about an axis A (FIG.  2 ), the spool  4 , and a handle assembly  1  that is rotatably supported on the reel main body  2 . As is described in greater detail below, rotation of the handle assembly  1  with respect to the reel main body  2  causes the rotor  3  to rotate and causes the spool  4  to undergo oscillations along the axis A (FIG. 2) in order to receive the fishline. 
     The rotor  3  is rotatably supported by a front portion of the reel main body  2  and is rotatable about the above mentioned axis A. The spool  4  has an outer peripheral surface about which the fishline is wound, and is disposed on a front portion of the rotor  3  so as to be movable back and forth (oscillate) along the axis A. 
     STRUCTURE OF THE HANDLE ASSEMBLY 
     As shown in FIG. 3, the handle assembly  1  is threaded into a master gear shaft  10 , as is described below. As shown in FIG. 1, the handle assembly  1  includes a T-shaped handle portion  1   a  and a L-shaped crank arm  1   b.  The handle portion  1   a  is rotatably attached to an end of the crank arm  1   b.  With reference again to FIG. 3, the crank arm  1   b  includes an arm portion  7   a,  a shaft portion  7   b,  and an attachment portion  7   c.  A base end of the arm portion  7   a  is pivotally coupled to the shaft portion  7   b.  The attachment portion  7   c  has a cup-like shape and extends around a portion of the shaft portion  7   b,  as is described in greater detail below. The attachment portion  7   c  is substantially concentric with the shaft portion  7   b  with the shaft portion  7   b  extending beyond the end of the attachment portion  7   c  such that the distal end of the shaft portion  7   c  is threaded into the master gear shaft  10 . 
     The shaft portion  7   b  has a rod-shaped cross section. On the distal end (toward the right side of FIG. 3) of the shaft portion  7   b,  a first male screw portion  8   a  and a second male screw portion  8   b  are formed concentrically and axially next to each other. The first male screw portion  8   a  is a right-handed screw (a screw that is threaded in when it rotates in a clockwise direction). The second male screw portion  8   b  is a left-handed screw (a screw that is threaded in when it rotates in a counter-clockwise direction) that has a larger diameter than the first male screw portion  8   a.  Accordingly, the handle assembly  1  can be attached to either the right side of the reel main body  2  as shown in FIGS. 1 and 2, or the left side of the reel main body  2  as shown in FIG.  3 . 
     On a base end of the shaft portion  7   b,  flat surfaces  8   c  are formed parallel to each other. A bore  8   d  is formed on the flat surfaces  8   c  for receiving therein a pivot pin  8   e  which pivotally supports the arm portion  7   a  on the shaft portion  7   b.  The arm portion  7   a  is pivotally coupled to the shaft portion  7   b  via the pivot pin  8   e.    
     The attachment portion  7   c  includes a contacting portion  9   a,  a shaft cover  9   b,  and a pressure member  9   c.  The contacting portion  9   a  defines an end surface of the arm portion  7   a.  The shaft cover  9   b  has a cylindrical-shape that encircles an outer periphery of a portion of the shaft portion  7   b  but is spaced apart from the shaft portion  7   b.  The pressure member  9   c  surrounds a portion of the shaft portion  7   b  and is located between the outer surface of the portion of the shaft portion  7   b  and the shaft cover  9   b.    
     The contacting portion  9   a  of the attachment portion  7   c  is formed with an opening that engages the flat surfaces  8   c  of the shaft portion  7   b  such that the shaft cover  9   b  cannot rotate relative to the shaft portion  7   b.  In this way, the shaft portion  7   b  can be rotated by rotation of the shaft cover  9   b  such that the shaft portion  7   b  may be threaded into the master gear shaft  10  and later removed (unthreaded) from the master gear shaft  10  by rotation of the shaft cover  9   b.  An end of the shaft cover  9   b  extends around a tubular cover  19   b  that is supported on the reel main body  2 . 
     The pressure member  9   c  is tubular in shape and is coupled to the shaft portion  7   b  but is rotatable and axially movable with respect to the shaft  7   b,  as is described further below. The end of the pressure member  9   c  contacts the master gear shaft  10  while the handle assembly  1  is attached thereto. On the outer periphery of the shaft portion  7   b  between the pressure member  9   c  and the contacting portion  9   a  of the shaft cover  9   b  there are four plate springs  9   d  that are arranged as two pairs of plate springs. Further, between the contacting portion  9   a  and the plate springs  9   d  a washer  9   e  is disposed encircling the shaft portion  7   b.  The two pairs of plate springs  9   b  contact each other at outer peripheries thereof. When the handle assembly  1  is attached to the master gear shaft  10  the plate springs  9   d  are compressed between the pressure member  9   c  and the washer  9   e  such that the biasing force of the plate springs  9   d  biases the pressure member  9   c  into firm engagement with the master gear shaft  10  thereby preventing the shaft portion  7   b  from becoming unscrewed from the master gear shaft  10 . Specifically, the biasing force that urges the pressure member  9   c  against the master gear shaft  10  helps to retain one of the first male screw  8   a  or the second male screw  8   b  in threaded engagement with the corresponding threads in the master gear shaft  10 . As well, with the plate springs  9   c  under compression, the contacting portion  9   a  further contacts an end surface of the arm portion  7   a  such that the arm portion  7   a  is not able to pivot about the pin  8   e.    
     When the handle assembly  1  is to be removed from the master gear shaft  10 , the shaft cover  9   b  is rotated to loosen the threaded engagement between the shaft portion  7   b  and the master gear shaft  10 . As the shaft portion  7   b  begins to become unscrewed (unthreaded) from the master gear shaft  10 , the plate springs  9   d  expand and are no longer compressed, and the contacting portion  9   a  becomes separated from the shaft cover  9   b.  The contacting portion  9   a  also comes out of contact with the end surface of the arm portion  7   a  of the crank arm  1   b.  Accordingly, the crank arm  1   b  can easily pivot about the pivot pin  8   e.  When the handle assembly  1  is threaded in by rotating the shaft cover  9   b,  the contacting portion  9   a  contacts the end surface of the arm portion  7   a  whereby the handle assembly  1  is retained rigidly in an attachment state where the crank arm  1   b  cannot pivot about the pivot pin  8   e.  While the handle assembly  1  is attached to the master gear shaft  10 , the plate springs  9   d  bias the pressure member  9   c  towards the master gear shaft  10 , whereby the attachment of the handle assembly  1  to the master gear shaft  10  does not come loose easily. 
     STRUCTURE OF REEL MAIN BODY 
     As is shown in FIGS. 1,  2  and  3 , the reel main body  2  includes a reel body  2   a  and a leg  2   b.  The reel body  2   a  has an opening  2   c  on a side portion thereof (the opening  2   c  is open toward the left side of FIG.  3 ). The leg  2   b  has a shape resembling the letter T and is shaped to connect the reel main body to a portion of a fish rod (not shown). The leg  2   b  is formed on the reel body  2   a  integrally therewith, and extends in an upward direction therefrom. The opening  2   c  is shaped to receive a lid member  2   d  thereby closing the reel main body. 
     As shown in FIG. 2, inside the reel body  2   a  there is a space for many elements which define several mechanisms. The space within the reel body  2   a  is accessed via the opening  2   c  by removing the lid member  2   d.  Within the space within the reel body  2   a  are a rotor driving mechanism  5  for rotating the rotor  3  in response to rotation of the handle assembly  1 , and an oscillating mechanism  6  that moves the spool  4  back and forth along the axis A such that the fishline (not shown) may be uniformly wound around the spool  4  by rotation of the rotor  3 . 
     As shown in FIG. 3, the opening of the reel body  2   a  is closed and sealed by a lid member  2   d.  The lid member  2   d  is fixedly connected to an outer periphery of the opening  2   c  by bolts. On a peripheral portion of the opening  2   c,  a liquid gasket  80  is applied as shown in FIG. 4 in hatched shading, to seal a gap between the lid member  2   d  and the opening  2   c,  thereby preventing liquid from entering the reel body  2   a  and contaminating the moving elements of the mechanism therein. It should be appreciated that the hatched shading in FIG. 4 representing the liquid gasket  80  is not an indication of a cross-section, but rather is an indication of the liquid gasket  80 . 
     FIG. 4 shows a first flange portion  2   e  formed on a front portion of the reel body  2   a.  The first flange portion  2   e  generally has a semi-cylindrical shape, or in other words is approximately half of a cylinder in shape. The first flange portion  2   e  is formed on the reel body  2   a  and extends forward in front of the opening  2   c.  A second flange portion  2   f  is fixed to the first flange portion  2   e  and the reel body  2   a.  The second flange portion  2   f  has a semi-cylindrical shape and completes a cylinder shape with first flange portion  2   e.  A one-way clutch  51  of a reverse rotation prevention mechanism  50  is fixed to the first flange portion  2   e  (and second flange portion  2   f,  as shown in FIG.  2 . The one-way clutch  51  allows the rotor  3  to rotate in one direction, but prevents the rotor  3  from rotating in an opposite direction. 
     As is indicated in FIG. 4, the second flange portion  2   f  is a separate member from the reel body  2   a  and makes it easy to install the various elements that are retained within the reel body  2   a.  The configuration of the second flange portion  2   f  is such that the master gear  11  is closer to a front of the interior of the reel body  2   a  than in prior art configurations. A water repellent seal  81  made of an elastic material is disposed on surfaces of the second flange portion  2   f  that contact the first flange portion  2   e  and the lid member  2   d.  As shown in FIG. 4, the water repellent seal  81  is disposed in a semi-circular shape on a rear surface of the second flange portion  2   f  facing the lid member  2   d.  The water repellent seal  81  is also disposed on surfaces that contact the first flange portion  2   e.    
     The one-way clutch  51  has a shape corresponding to the cylinder defined by the combination of the first flange portion  2   e  and the second flange portion  2   f.  A tubular seal ring  82  made of an elastic material such as NBR is disposed on an outer periphery of the one-way clutch  51  and the first and second flange portions  2   e  and  2   f,  as shown in FIG. 6, such that any outer peripheral gaps formed on the one-way clutch  51  and the first and second flange portions  2   e  and  2   f,  along with a gap formed between the one-way clutch  51  and the first and second flange portions  2   e  and  2   f  are all sealed. 
     As shown in FIGS. 3 and 5, a cylindrical boss portion  17   a  is formed on one side of the reel body  2   a  (toward the right side of FIG.  5 ). The boss portion  17   a  extends inwardly within the reel body  2   a  for supporting a bearing  16   a  which supports one end of the master gear shaft  10 . Another boss portion  17   b  is formed on the lid member  2   d  opposing the boss portion  17   a,  and with the lid member  2   d  fixed in the opening  2   c,  the boss portion  17   a  and boss portion  17   b  are axially aligned. The boss portion  17   b  extends both inward and outward from the space within the reel body  2   a  for supporting a bearing  16   b  which further supports another end of the master gear shaft  10  (on the left side of FIG.  5 ). The boss portion  17   a  of the reel body  2   a  is covered by a shaft cover  19   a.  However, the shaft cover  19   a  can be removed and the handle assembly  1  may be threaded into the master gear shaft  10  via the opening defined by the bearing  16   a.    
     The tubular cover  19   b  may be coupled to either of the boss portions  17   a  or  17   b  on opposite sides of the reel body  2   a,  depending upon which side of the reel body  2   a  the handle assembly  1  is attached to (i.e. for a left-handed user or a right handed user). The tubular cover  19   b  prevents water from entering the reel main body  2   a.  As shown in FIG. 1, the shaft cover  19   a  and tubular cover  19   b  are oval members, both adapted to be coupled to either boss portion  17   a  and  17   b  by two small bolts  19   c.  The surface of the reel body  2   a  around the boss portion  17   a  is formed with an oval recess  17   c  for attachment of either the shaft cover  19   a  or the tubular cover  19   b.    
     STRUCTURE OF THE ROTOR DRIVING MECHANISM 
     As shown in FIG. 3, the rotor driving mechanism  5  includes a master gear  11  to which the handle assembly  1  is non-rotatably attached via the master gear shaft  10 . The rotor driving mechanism  5  also includes the pinion gear  12  that has gear teeth engaged with corresponding gear teeth formed on the master gear  11 . 
     As shown in FIG. 5, the master gear  11  includes the master gear shaft  10 , a gear attachment portion  11   a  integrally formed with the master gear shaft  10 , and the gear member  11   b  detachably coupled to the gear attachment portion  11   a.    
     The master gear shaft  10  is a hollow member made of a stainless steel material. Both ends of the master gear shaft  10  are rotatably supported by the reel body  2   a  and the lid member  2   b  via the bearings  16   a  and  16   b.  The bearings  16   a  and  16   b  are rotary bearings, each having an inner race  20   a,  an outer race  20   b,  and ball bearings  20   c.  Seal rings  18   a  and  18   b  made of an elastic material such as NBR are disposed adjacent to the outer peripheral surface of the master gear shaft  10 , and axially outward from the internal space of the reel body  2   a,  the inner race  20   a  and the outer race  20   b  of the bearings  16   a  and  16   b,  respectively. 
     The seal rings  18   a  and  18   b  are washer-like members, tightly retained within seal coupling recesses  18   c  and  18   d,  which are formed in the lid member  2   d  and reel body  2   a,  respectively, axially outward from the bearings  16   a  and  16   b.  Inner radiuses of the seal coupling recesses  18   c  and  18   d  (outer radiuses of the seal rings  18   a  and  18   b ) are smaller than outer radiuses of the bearings  16   a  and  16   b.  Axial lengths of the seal coupling recesses  18   c  and  18   d  are slightly smaller than thicknesses of the seal rings  18   a  and  18   b.  Inner peripheries of the seal rings  18   a  and  18   b  are disposed adjacent to seal surfaces  10   e  and  10   f  of the master gear shaft  10 . Outer radiuses of the seal surfaces  10   e  and  10   f  are smaller than the radiuses of the portion of the main gear shaft  10  that contacts the bearings  16   a  and  16   b.    
     Small bolts  18   e  and  18   f  are threaded into the boss portions  17   a  and  17   b  contacting the outer races  20   b  of the bearings  16   a  and  16   b.  The small bolts  18   e  and  18   f  through the outer races  20   b  force the seal rings  18   a  and  18   b  into firm engagement with the seal coupling recesses  18   c  and  18   d  such that the seal rings  18   a  and  18   b  seal outer peripheral portions thereof without rotating with the master gear shaft  10 . Since the seal surfaces  10   e  and  10   f  have smaller radiuses than the bearing attachment surfaces, it is less likely that the seal surfaces  10   e  and  10   f  are damaged. Further, after repeated attachment and detachment of the handle assembly  1 , if the master gear shaft  10  should be deformed thereby extending farther in a radially outward direction, the seal rings  18   a  and  18   b  may still provide a reliable seal. Also, since the seal coupling recesses  18   c  and  18   d  have smaller radiuses than the outer races  20   b,  thrust forces that are applied to the bearings  16   a  and  16   b  can be directly supported by the reel body  2   a  and the lid member  2   d.    
     As shown in FIG. 5, the master gear shaft  10  is formed with a first through bore  10   a,  a first female screw portion  10   b,  a second through bore  10   c,  and a second female screw portion  10   d  all formed concentrically and axially aligned in the above recited order from the right side of FIG. 4 to the left side of FIG.  5 . The second female screw portion  10   d  opens to the left end of the master gear shaft  10 . The axial length of the first through bore  10   a  is substantially the same as the axial length of the second female screw portion  10   d.  The first through bore  10   a  has a larger radius than the second female screw portion  10   d,  such that the second male screw portion  8   b  of the shaft portion  7   b  can be inserted therethrough. The first female screw portion  10   b  is formed with right-handed screw threads, into which the first male screw portion  8   a  of the shaft portion  7   b  can be threaded. The axial length of the first female screw portion  10   b  is slightly longer than the axial length of the first male screw portion  8   a.  The axial length of the second through bore  10   c  is substantially the same as the axial length of the first female screw portion  10   b.  The second through bore  10   c  has a larger diameter than the first female screw portion  10   b,  such that the first male screw portion  8   a  can be inserted therethrough. The second female screw portion  10   d  is threaded with left-handed screw threads, into which the second male screw portion  8   b  of the shaft portion  7   b  can be threaded. 
     On portions of the outer surface of the master gear shaft  10  are flat surfaces  10   g  formed parallel to each other for engagement with corresponding surfaces of the gear attachment portion  11   a.  The gear attachment portion  11   a  is formed on the flat surfaces  10   g  integrally with the master gear shaft  10  by press fitting the master gear shaft  10  into the gear attachment portion  11   a  or other means. The gear attachment portion  11   a  is made of a zinc alloy, which can be molded integrally with a stainless alloy easily. The gear attachment portion  11   a  includes a boss portion  11   c  and a flange portion  11   d.  The boss portion  11   c  is fixedly coupled to the master gear shaft  10 , as described above. The flange portion  11   d  is formed on an outer periphery of the boss portion  11   c.  The gear member  11   b  is detachably coupled to the flange portion  11   d  by a plurality of bolts  13 . The gear member  11   b  is a disk shaped member made by forging an aluminum alloy. Therefore, the gear member  11   b  is relatively light. The gear member  11   b  includes a disk portion  11   e  and the face gear portion  11   f.  The disk portion  11   e  is non-rotatably coupled to the flange portion  11   d.  The face gear portion  11   f  is formed on the outer peripheral portion of the disk portion  11   e,  and is adapted to engage gear teeth formed on the pinion gear  12 . 
     As shown in FIG. 2, the pinion gear  12  is a tubular member disposed extending around a portion of the axis A in a generally central portion of the reel body  2   a.  The pinion gear  12  is restrained within the reel body  2   a  against axial movement along the axis A, but rotates about a spool shaft  15 . A front portion  12   a  of the pinion gear  12  extends through a central portion of the rotor  3 . The front portion  12   a  is fixed to the rotor  3  by a nut  33 . The pinion gear  12  is rotatably supported by the reel body  2   a  at two spaced axially spaced apart portions via bearings  14   a  and  14   b,  respectively. The spool shaft  15  extends completely through the pinion gear  12 . The pinion gear  12  is formed with gear teeth engaged with the gear teeth on the master gear  11  and further engaged with gear teeth on an intermediate gear  23  of an oscillating mechanism  6 , described in greater detail below. 
     ROTOR STRUCTURE 
     As shown in FIG. 2, the rotor  3  includes a cylindrical portion  30  fixed to the pinion gear  12 , first and second rotor arms  31  and  32 , and a bail arm  40 . The first and second rotor arms  31  and  32  are formed on side portions of the cylindrical portion  30  opposed to and parallel to each other. The bail arm  40  is a mechanism for guiding the fishline on to the spool  4  as the rotor  3  rotates about the spool  4 . The cylindrical portion  30  and the rotor arms  31  and  32  are made of a material such as an aluminum alloy, and are formed integrally together as a one-piece unit. A front central portion of the cylindrical portion  30  is non-rotatably fixed to the front portion  12   a  of the pinion gear  12  by the nut  33 , as described above. A rotor bearing  35  is fitted between the nut  33  and the spool shaft  15 . The outer race of the rotor bearing  35  is held in a recess in the nut  33 , and the inner race of the bearing  35  is fixedly mounted to the shaft  15 . A seal  34  is fitted into a recess in the nut  33  that is axially outward from and diametrically larger than the recess for the bearing  35 . A locking cap  33   a  is fastened over the nut  33  to the front wall and retains the seal  34 . 
     A front wall  41  is formed on a front portion of the cylindrical portion  30 . A boss portion  42  is formed on a central portion of the front wall  41 . The boss portion  42  has a through bore formed in the center thereof. The front portion  12   a  of the pinion gear  12  and the spool shaft  15  extend through the through bore of the boss portion  42 , such that the pinion gear  12  is non-rotatably coupled to the through bore. 
     A reverse rotation prevention mechanism  50  is disposed within the cylindrical portion  30 , adjacent to the boss portion  42 . The reverse rotation prevention mechanism  50  includes a one-way clutch  51  and a switching mechanism  52 . The one-way clutch  51  is a roller type one-way clutch, in which an inner race  51   a,  which is non-rotatably coupled to the pinion gear  12 , freely rotates. The switching mechanism  52  switches the one-way clutch  51  between an active state, in which reverse rotation is prevented, and an inactive state, in which reverse rotation is allowed. 
     As shown in FIG. 6, a sleeve  43  made of a stainless alloy is retained between the inner race  51   a  and the boss portion  42  of the rotor  3 . The sleeve  43  is a thin tubular member having a large diameter portion  43   a,  a small diameter portion  43   b,  and a disk portion  43   c  extending therebetween. The large diameter portion  43   a  is coupled to an outer periphery of the boss portion  42 , while the small diameter portion  43   b  is coupled to the inner race  51   a  and the pinion gear  12 . The disk portion  43   c  that connects the large portion  43   a  and the small portion  43   b  is disposed between the boss portion  42  and the inner race  51   a.    
     A shaft seal  85  having a lip is retained on a front portion of the one-way clutch  51 . The lip contacts an outer peripheral surface of the large diameter portion  43   c  of the sleeve  43 . Since the disk portion  43   c  is disposed between the boss portion  42  and the inner race  51   a,  it is unlikely that liquid can enter the cylindrical member  30  (FIG. 2) through a gap formed in the inner periphery of the sleeve  43 . Therefore, by sealing with the shaft seal  85  an outer peripheral surface of the sleeve  43 , liquid does not enter inside the reel main body  2  through gaps around the one-way clutch  51 . The sleeve  43  allows a precise positioning of the shaft seal  85  relative to the rotor  3 . Without the sleeve  43 , if the rotor  3  is offset from the shaft seal  85  while the rotor is coupled to the pinion gear  12 , the shaft seal  85  cannot seal properly. By utilizing the sleeve  43 , the shaft seal  85  can be more easily positioned relative to the rotor  3  such that the shaft seal  85  can seal properly. 
     As shown in FIGS. 2 and 4, the reel body  2   a  includes a switching mechanism  52  that has a stopper shaft  53 . The stopper shaft  53  is pivotably coupled to the reel body  2   a  so as to be able to move between an inactive position and an active position. As shown in FIG. 7, the stopper shaft  53  has a stopper handle  53   a,  a shaft portion  53   b,  and a cam portion  50   c.  The stopper handle  53   a  projects in a rearward direction through the reel body  2   a.  The stopper handle  53   a  is fixedly connected to the shaft  53   b.  The cam portion  50   c  is fixedly coupled to a front end of the shaft portion  53   b.  An O-shaped ring  86  is installed on the shaft portion  53   b,  at an inward portion relative to the stopper handle  53   a.  The O-shaped ring  86  prevents liquid from entering the reel main body  2   a  through gaps that may exist around the stopper shaft  53 . A front portion of the cam portion  53   c  contacts the one-way clutch  51 , so as to switch the one-way clutch  51  between the inactive position and the active position according to pivoting of the stopper shaft  53 . 
     STRUCTURE OF THE OSCILLATING MECHANISM 
     As shown in FIG. 7, the oscillating mechanism  6  includes a threaded shaft  21  disposed below and parallel to the spool shaft  15 , a slider  22  adapted to move back and forth along the threaded shaft  21 , and an intermediate gear  23  fixed to a front end of the threaded shaft  21 . A rear end of the threaded shaft  21  is rotatably supported via the bearing  25  in a support bore  2   g  that is formed on a rear portion of the reel body  2   a.  The support bore  2   g  is sealed by a pressure lid  88 . A planar seat packing member  87  is disposed on a rear portion of the reel body  2   a  to prevent liquid from entering inside the reel main body  2   a  through a gap between the pressure lid  88  and the reel body  2   a.  The seat packing member  87  is disposed between the pressure lid  88  and the rear portion of the reel body  2   a,  and is fixedly coupled to the rear portion of the reel body  2   a  by the pressure lid  88  which is fixedly coupled the rear portion of the reel body  2   a  by a small bolt  89 . The rear portion of the reel body  2   a  is covered by a protection cover  90 . 
     The slider  22  is movably supported by two guide shafts  24  that are disposed parallel to the threaded shaft  21 . A rear end of the spool shaft  15  is non-rotatably coupled to the slider  22 . The intermediate gear  23  couples with the pinion gear  12 . 
     SPOOL STRUCTURE 
     As shown in FIG. 2, the spool  4  is disposed between the first rotor arm  31  and the second rotor arm  32  of the rotor  3 . A central portion of the spool  4  is coupled to the front end of the spool shaft  15  via a drag mechanism  60 . The spool  4  includes a winder body  4   a,  a skirt portion  4   b,  and a flange board  4   c.  The fishline is wound about an outer periphery of the winder body  4   a.  The skirt portion  4   b  is formed integrally with a back portion of the winder body  4   a.  The flange board  4   c  is fixed to a front end of the winder body  4   a.  The winder body  4   a  is a cylindrical member, having the outer peripheral surface that is parallel to the spool shaft  15 . As shown in FIG. 6, the winder body  4   a  is rotatably coupled to the spool shaft  15  by two bearings  56  and  57 . 
     The skirt portion  4   b  is disk shaped and extends in a radially outward direction from a rear end portion of the winder body  4   a.  A thread through bore  93  is formed on a portion of the skirt portion  4   b  adjacent to the winder body  4   a.  One end of the fishline (not shown) wound around the winder body  4   a  extends through the bore  93  and is anchored to the skirt portion  4   b  by tying the fishline to a projection  92  formed on a rear surface of the skirt portion  4   b  radially outward from the bore  93 . By tying an end of the fishline to the projection  92 , a knot at the end of the fishline is not wound in the winder body  4   a.  Therefore, the fishline can be wound evenly about the winder body  4   a  when a thin fishline is used. As a result, the fishline can be pulled out from the spool smoothly, with an improved smoothness of rotation. 
     The flange board  4   c  is an annular ring-shaped member having an outer peripheral portion that projects in a front direction relative to the reel main body  2   a.  The flange board  4   c  is fixedly coupled to the winder body  4   a  by a spool ring collar  55  that is threaded to an inner periphery of the winder body  4   a.    
     The spool  4  is supported on the bearing  57  that is retained in position at one end thereof on the spool shaft  15  by a positioning washer  54  that is coupled to the spool shaft  15 . A seal ring  91  made of an elastic material is disposed between the positioning washer  54  and the bearing  57 , adjacent to inner and outer races of the bearing  57  and a portion of the spool  4  where the bearing  57  is retained. The seal ring  91  is a washer-shaped member for preventing liquid from entering the drag mechanism  60  through a rear portion of the spool  4 . 
     DRAG MECHANISM STRUCTURE 
     As shown in FIGS. 2 and 6, an adjustable drag mechanism  60  is disposed between the spool  4  and the spool shaft  15  for applying a drag force to the spool  4 . As shown in FIG. 6, the drag mechanism  60  includes a handle portion  61  and a friction portion  62 . The handle portion  61  allows the amount of drag force to be controlled manually. The friction portion has a plurality of disks that are pressed into friction engagement with one another and further coupled to the spool  4 . 
     The handle portion  61  includes a first member  63 , a second member  64 , and a sound mechanism  65 . The first member  63  is rotatably and axially movably coupled to the spool shaft  15 . The second member  64  is disposed at an axially front position with respect to the first member  63 . The spool shaft  15  is threaded into the second member  64 . The sound mechanism  65  is coupled between the first member  63  and the second member  64 . 
     The first member  63  is a cylindrical member with a flange, having a cylindrical portion  63   a  and a flange portion  63   b  is a ring having a larger diameter than the cylindrical portion  63   a.  An oval coupling bore  66  is formed on an inner peripheral portion of the cylindrical portion  63   a  for non-rotatably coupling with the spool shaft  15 . A rear end surface of the cylindrical portion  63   a  of the first member  63  is disposed adjacent to a friction surface  62 . A seal plate  71  is coupled between the cylindrical portion  63   a  of the first member  63  and an inner peripheral surface of the spool ring collar  55  for preventing liquid from entering inside the spool  4 . The seal plate  71  is a seal member made by inserting a ring-shaped member made of a stainless material into a plate-shaped elastic member made of NBR. The seal plate  71  has a lip on an outer peripheral portion thereof. The seal plate  71  is biased by a snap ring  79  in a direction shown as a leftward direction in FIG. 6. A ring-shaped projection  71   c  is formed on the seal plate  71 , which extends to the left side of FIG.  6 . The projection  71   c  contacts a cover member  68 , which is described below, for preventing the liquid from entering from outside the spinning reel. 
     The second member  64  is disposed opposite the first member  63  so as to be rotatable relative to the first member  63 . The second member  64  includes a handle body  67  and a cover member  68 . The handle body  67  is disposed on a front end of the spool shaft  15  (to the left side of FIG. 6 relative to the first member  63 ). A front end of the cover member  68  is fixedly coupled to the handle body  67 . The first member  63  is relatively rotatably disposed within the cover member  68 . 
     The handle body  67  is a disk-shape member having a trapezoid-shaped handle  67   a  which is formed on a front surface thereof and extends toward the front of the spinning reel (the left side of FIG.  6 ). A nut  69 , which is threaded into the front end of the spool shaft  15 , is non-rotatably and axially movably coupled to an inner periphery of the handle body  67 . A coil spring  70  is disposed in a compressed manner on an outer periphery of the spool shaft  15 , between the second member  64  and the nut  69 . 
     The cover member  68  is cylindrically shaped having a bottom portion  68   b  and a cylindrical portion  68   a.  The cylindrical portion  63   a  of the first member  63  passes through the bottom  68   b  of the cover member  68 . The projection  71   c  of the seal plate  71  contacts the bottom portion  68   b  of the cover member  68 . The cylindrical portion  68   a  of the cover member  68  is coupled to an outer peripheral surface of the handle body  67  via screws (not shown). 
     An annular seal ring  72  is disposed between the bottom  68   b  of the cover member  68  and a rear end surface of the cylindrical portion  63   a  of the first member  63 . An O-shaped ring  73  is coupled between a front end of the cylindrical portion  68   a  of the cover member  68  and the handle body  67 . The seal ring  72  and the O-shaped ring  73  are both made of an elastic material such as NBR, and prevent liquid from entering inside the spool  4  through gaps between the first member  63  and the cover member  68 , and between the handle body  67  of the second member  64  and the cover member  68 . In prior art configurations, once liquid enters inside the spool  4  through these gaps (in the absence of sealing members), the liquid reaches the friction portion  62  through the gap between the first member  63  and the spool shaft  15 , even with the seal plate  71 . As a result, drag force may fluctuate due to the wet friction portion  62 . 
     The friction portion  62  includes a first disk  101 , a second disk  102 , and a drag sound mechanism  103 . The first disk  101  contacts the first member  63 . The second disk  102  contacts the first disk  101  with a felt material therebetween. The drag sound mechanism  103  contacts the second disk  102  with a felt material therebetween. An inner peripheral portion of the first disk  101  is coupled to the spool shaft  15 , so as to rotate together therewith. An outer peripheral portion of the second disk  102  is coupled to the spool  4 , so as to rotate together therewith. The drag sound mechanism  103  generates a sound when the spool shaft  15  and the spool  4  rotate relative to each other, in other words, while the drag mechanism is active. 
     OPERATION OF THE REEL 
     In the above described spinning reel, the bail arm  40  is pivoted into a casting position so that the fishline can be released during casting. As a result, the fishline is let out from the front end of the spool  4  due to the weight of a lure (not shown). 
     When the fishline is to be wound up, the bail arm is turned back to a fishline wind-up position. The bail arm comes back to the fishline wind-up position automatically when the handle assembly  1  rotates in a direction that winds up the fishline, because of a bail reverse mechanism which is not shown in the drawings. Rotational torque of the handle assembly  1  is transmitted to the pinion gear  12 , via the master gear shaft  10  and the master gear  11 . Once torque is transmitted to the pinion gear  12 , the torque is further transmitted to the rotor  3  from the front portion  12   a  of the pinion gear  12 , and also to the oscillating mechanism  6  via the intermediate gear  23  which couples to the pinion gear  12 . As a result, the rotor  3  rotates in the direction that winds the fishline around the spool  4  while the spool  4  moves back and forth repeatedly to evenly allow winding of the fishline. 
     During fishing, water spray and waves occasionally splash on a reel, and the reel becomes wet. Even when the reel becomes wet, since the drag mechanism  60  is equipped with the seal plate  71 , the seal ring  72 , and the O-shaped ring  73 , and also since the spool  4  is equipped with the seal ring  91 , water entering inside the reel from front and rear portions thereof is not likely to reach the friction portion  62 . Therefore, once a drag force is adjusted, the drag force will not be changed because of the wet friction portion  62 . Also, seal members such as the seal rings  18   a  and  18   b,  the shaft seal  34 , the liquid gasket  80 , the water repellent sealing  81 , the seal ring  82 , the shaft seal  85 , the O-shaped ring  86 , the seal plate  87  are disposed between the reel body  2   a  and mobile, stationary, and constituting members, liquid is prevented from entering inside the reel main body  2   a.  Therefore, it is unlikely that seawater enters inside the reel. Accordingly, deposits such as crystals of salt will not remain inside the bearings or guide portion. Therefore, there is no need to apply a highly viscous grease inside the reel. Also, it is less likely that deposits will be trapped between the gears and rollers, whereby the handle rotates more smoothly. 
     ALTERNATE EMBODIMENTS 
     (a) Although a front-drag type spinning reel was described in the above embodiment, the present invention can be applied to water-proof structures of other types of spinning reels, including a rear-drag type spinning reel, a spinning reel without a drag, and a lever-drag type spinning reel. 
     (b) Although seal members were disposed on constituting members and stationary members, not only on moveable members such as a master gear, seal members can be applied to only one of the constituting, stationary, and moveable members. 
     EFFECT OF THE INVENTION 
     According to the present invention, since liquid can be prevented from entering the reel main body through gaps between moveable members, stationary members, and a reel body, grease with low viscosity can be utilized. Therefore, resistance due to viscosity of the grease decreases, thereby improving the efficiency of winding a handle. Also since liquid is prevented from entering the interior spaces of the reel main body, there are less deposits which remain after liquid evaporates, whereby deposits are less likely to be trapped between gears and rollers. In this way, rotation of the handle will be smooth. 
     Various details of the invention may be changed without departing from its spirit nor its scope. Furthermore, the foregoing description of the embodiments according to the present invention is provided for the purpose of illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.