Abstract:
A stator according to the present invention includes a stator hub, a large number of blades radially provided in a projecting manner at regular intervals on an outer periphery of the stator hub, and a stator core formed so as to surround outer ends of the respective blades. The stator is integrated by separately molding a front side stator member and a rear side stator member as two axially split members, respectively, and then joining the front side stator member and the rear side stator member.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a stator to be used mainly for a torque converter in an automobile and the like. 
         [0003]    2. Description of the Related Art 
         [0004]    A stator in a torque converter of an automobile is disposed between a turbine runner located on an engine side and a pump impeller located on a transmission side. Moreover, the stator has a function of amplifying torque on the engine side by controlling the flow of oil circulating between the turbine runner and pump impeller to efficiently apply oil on the turbine runner side to the pump impeller side. 
         [0005]    As shown in  FIG. 8  and  FIG. 9 , commonly, a stator  41  is cast molded using an aluminum alloy or the like and integrated in whole. Specifically, the stator  41  includes a stator hub  43  fixed to an outer periphery of a one-way clutch  42  for supporting on a stationary shaft (not shown), a stator core  44  formed out of the stator hub  43 , blades  45  in predetermined shapes provided, between the stator core  44  and the stator hub  43 , radially at regular intervals in a circumferential direction of the stator core  44  and the stator hub  43 . Also, a retainer  46  is attached to a front side of the one-way clutch  42 . 
         [0006]    As shown in  FIG. 10 , a wing section (sectional shape of a wing) of the blade  45  in the stator  41  has been provided with a radius of curvature of a camber line CL set larger than that shown in the drawing to thereby enhance the rotation of the pump impeller in order to increase the torque amplifying function of the stator  41 . 
         [0007]    In addition to the above, various stators are also known which are structured such that, in order to perform a series of torque transmissions from the time of idling to the time of starting of an automobile efficiently and actively, by dividing each blade into two front and rear members and varying the front side wing member and rear side wing member in positional relationship, the camber line CL and wing section are changed according to the situation so as to appropriately control hydraulic oil in the circulation channel area. 
         [0008]    As shown in  FIG. 11 , commonly, in an injection molding die for molding a stator, inserts  53  and  54  are disposed within a pair of holders  51  and  52 , respectively, and a cavity C for molding a stator in a predetermined shape is formed between the inserts  53  and  54 . Then, merely moving the holders  51  and  52  in an axial direction A, B (die stroke direction) of said molding die after molding a stator in a predetermined shape allows releasing the stator from the die (hereinafter, referred to as “axial releasing molding”). 
         [0009]    However, in the case of a stator including blades having a large radius of curvature of the camber line CL described above, simply moving the holders  51  and  52  in the axial direction A, B of said molding die as described above results in a situation of a die releasing failure due to a part of the blades being caught on the insert  53 ,  54 . 
         [0010]    Therefore, as shown in  FIG. 12 , it has been necessary to dispose sliding cores  65  for forming respective blades of a stator between insert dies  63  and  64  within a pair of holders  61  and  62  in large numbers in a circumferential direction and mold a stator hub and blades in the cavity C, and then move the holders  61  and  62  in an axial direction A, B and cause a releasing movement of the respective sliding cores  65  in a radial direction D, E (direction orthogonal to a die stroke direction) (hereinafter, referred to as “radial releasing molding”). However, such radial releasing molding has had a drawback that it requires a great deal of labor for the molding operation as compared with that in the case of axial releasing molding described above. Also, after such radial releasing molding, because it is further necessary to wrap a band in a manner surrounding outer ends of the respective blades radially projecting from an outer periphery of the molded stator hub so as to form an annular stator core, there has been a problem that a great deal of time and cost is required for manufacturing in combination with labor of the radial releasing molding operation described above. 
         [0011]    Also in the stators in which each blade is divided into two members, similar to the foregoing, there has been a drawback that a great amount of labor and time is required for a molding operation and final finishing operation. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    At least one object of the present invention is to enable axial releasing molding of a stator even when a radius of curvature of a camber line of its wind section (sectional shape of a wing) is large. 
         [0013]    Also, an object of the present invention is, when the camber line is increased in radius of curvature in order to increase the torque amplifying function of a stator, to obtain an integrated stator by merely joining a front side stator member and a rear side stator member respectively obtained by axial releasing molding. 
         [0014]    Further, another object of the present invention is to obtain a stator the camber line of which has a large radius of curvature by a method other than conventional radial releasing molding. 
         [0015]    Still another object of the present invention is to manufacture a stator having a large radius of curvature of a camber line of a wind section without requiring a great deal of labor, time, and cost. 
         [0016]    The present invention provides the following stator and a method for manufacturing the same and a torque converter including the stator. 
         [0017]    That is, the present invention is a split molded integrated stator being a stator including a stator hub, a large number of blades radially provided in a projecting manner at regular intervals on an outer periphery of the stator hub, and a stator core formed so as to surround outer ends of the respective blades, for which a front side stator member and a rear side stator member are respectively separately molded as two axially split members, and the front side stator member and the rear side stator member are jointed to be integrated. 
         [0018]    Also, an aspect of the present invention is a split molded integrated stator in which, as a splitting form into the front side stator member and the rear side stator member, the stator core and the blade are longitudinally split in a radial direction in a manner divided into two nearly equal front and rear parts and divided into a front side stator core member and a rear side stator core member and into a front side blade member and a rear side blade member, and the stator hub on an inner peripheral side has one of the front and rear side stator hub members in a range extending from an upper central part to an upper corner portion of the stator hub and has the other stator hub member in a remaining range. 
         [0019]    An aspect of the present invention is a torque converter including the split molded integrated stator described above. 
         [0020]    An aspect of the present invention is a method for manufacturing a split molded integrated stator being a stator including a stator hub, a large number of blades radially provided in a projecting manner at regular intervals on an outer periphery of the stator hub, and a stator core formed so as to surround outer ends of the respective blades, including a step of separately molding a front side stator member and a rear side stator member as two axially split members, respectively, and a step of joining the molded front side stator member and rear side stator member to be integrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a longitudinal sectional view of a stator at a first manufacturing stage in an embodiment of the present invention; 
           [0022]      FIG. 2  is a front view of a rear side stator member of the same stator at the first manufacturing stage; 
           [0023]      FIG. 3  is a wing section of a blade of the same stator at the first manufacturing stage; 
           [0024]      FIG. 4  is a longitudinal sectional view of a stator at a second manufacturing stage in the same embodiment; 
           [0025]      FIG. 5  is a wing section of a blade of the same stator at the second manufacturing stage; 
           [0026]      FIG. 6  is a longitudinal sectional view of a stator at a first manufacturing stage showing another embodiment of the present invention; 
           [0027]      FIG. 7  is a main part enlarged view showing an example of joining of a front side stator hub member and a rear side stator hub member in the embodiment of  FIG. 6 ; 
           [0028]      FIG. 8  is a longitudinal sectional view of a conventional ordinary stator. 
           [0029]      FIG. 9  is a front view of the stator in  FIG. 6 . 
           [0030]      FIG. 10  is a wing section of a blade of the stator in  FIG. 6 ; 
           [0031]      FIG. 11  is a schematic view of a die showing a procedure for axial releasing molding; and 
           [0032]      FIG. 12  is a schematic view of a die showing a procedure for radial releasing molding. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    Hereinafter, stators according to embodiments of the present invention will be described in accordance with the drawings, but the present invention is not limited to such embodiments. 
         [0034]    In the present application, a front-rear direction is defined with reference to  FIG. 1 , and “front” means a left-side direction in an axial direction of a stator in  FIG. 1 , and “rear” means a right-side direction of the same. 
         [0035]    As shown in  FIG. 1  and  FIG. 2 , the stator  1  is, for example, cast molded using an aluminum alloy or the like, and includes a stator hub  3  fixed to an outer periphery of a one-way clutch  2  for supporting on a stationary shaft (not shown), a stator core  4  formed out of the stator hub  3 , blades  5  in predetermined shapes provided, between the stator core  4  and the stator hub  3 , radially at regular intervals in a circumferential direction of the stator core  4  and the stator hub  3 , and also, a retainer  6  is attached to a front side of the one-way clutch  2 . 
         [0036]    Moreover, as shown in  FIG. 1  and  FIG. 3 , in the present embodiment, the stator  1  is, as a first manufacturing step, subjected to injection molding of axial releasing in a manner separated into a front side stator member  1 A and a rear side stator member  1 B such that the blades  5  are divided into two each in the front-rear direction (axial direction), the front side stator member  1 A is composed of a front side stator hub member  3 A, a front side stator core member  4 A, and front side blade members  5 A, and the rear side stator member  1 B is composed of a rear side stator hub member  3 B, a rear side stator core member  4 B, and rear side blade members  5 B. 
         [0037]    The blade  5 , in the present embodiment, has a large radius of curvature of its camber line CL. However, the blade  5 , as described above, in the first manufacturing step, has a construction divided into the front side blade member  5 A and the rear side blade member  5 B. 
         [0038]    Next, as shown in  FIG. 4  and  FIG. 5 , for the stator  1 , the front side stator member  1 A and the rear side stator member  1 B described above are finally united by various joining means as a second manufacturing step, so as to be integrated in whole. 
         [0039]    As the joining means, for example, as shown in  FIG. 1 , the front side stator member  1 A and the rear side stator member  1 B are caulked, in a contact part BF between the front side stator member  1 A and the rear side stator member  1 B, in a manner spaced at predetermined intervals in its circumferential direction. Also, as shown in  FIG. 2 , for whirl-stop between the front side stator member  1 A and the rear side stator member  1 B, for example, fitting projection portions  9  are provided at regular intervals on an inner periphery of the rear side stator member  1 B, and in the front side stator member  1 A, fitting recess portions (not shown) to be fitted with the fitting projection portions  9  are provided. 
         [0040]    Also, the front side stator member  1 A and the rear side stator member  1 B are coupled by, as another joining means between both members  1 A and  1 B, engaging the front side stator member  1 A and the rear side stator member  1 B by a C-ring and making a pin stand in a penetrating manner from the front side stator member  1 A to the rear side stator member  1 B. 
         [0041]    In addition, joining means other than those described above include mechanical joining such as press-fitting and metallurgical joining such as pressure welding. 
         [0042]    Describing in greater detail a splitting form into the front side stator member  1 A and the rear side stator member  1 B in the first manufacturing step of the stator  1  in the present embodiment, as shown in  FIG. 1  and  FIG. 3 , the stator core  4  and the blades  5  are longitudinally split in a radial direction in a manner divided into two nearly equal front and rear parts and divided into the front side stator core member  4 A and the rear side stator core member  4 B and into the front side blade members  5 A and the rear side blade members  5 B, and the stator hub  3  on an inner peripheral side has the rear side stator hub member  3 B in a narrow range extending from an upper central part c to an upper rear-side corner portion e, and a wide range excluding the rear side stator hub member  3 B is provided as the front side stator hub member  3 A. 
         [0043]    However, in the present invention, the splitting form of the stator  1  is not limited to the form described above, and may have any structure for splitting into two in the axial direction. 
         [0044]    Describing another embodiment of the present invention, as shown in  FIG. 6  and  FIG. 7 , the stator  21  has a splitting form that is opposite in the front-rear direction as compared with that of the stator  1  according to the embodiment described above. That is, the stator  21  is, as a first manufacturing step, subjected to injection molding of axial releasing in a manner separated into a front side stator member  21 A and a rear side stator member  21 B such that blades  25  are divided into two each in the front-rear direction (axial direction), and thus provided as a construction in which the front side stator member  21 A has a front side stator hub member  23 A, a front side stator core member  24 A, and front side blade members  25 A and the rear side stator member  21 B has a rear side stator hub member  23 B, a rear side stator core member  24 B, and rear side blade members  25 B. 
         [0045]    Now describing a splitting form into the front side stator member  21 A and the rear side stator member  21 B in the first manufacturing step of the stator  21  in the present embodiment, the stator core  24  and the blades  25  are longitudinally split in a radial direction in a manner divided into two nearly equal front and rear parts and divided into the front side stator core member  24 A and the rear side stator core member  24 B and into the front side blade members  25 A and the rear side blade members  25 B, and the stator hub  23  on an inner peripheral side has the front side stator hub member  23 A in a narrow range extending from an upper central part c to an upper front-side corner portion e, and a wide range excluding the front side stator hub member  23 A is provided as the rear side stator hub member  23 B. 
         [0046]    Next, describing joining of the front side stator member  21 A and the rear side stator member  21 B as a second manufacturing step, as shown in  FIG. 7 , in a contact part BF between the front side stator member  21 A and the rear side stator member  21 B, fitting recess portions  30  are formed in the front side stator member  21 A at regular intervals in a circumferential direction, and in the rear side stator member  21 B, fitting projection portions  29  to be fitted with the fitting recess portions  30  are formed. Moreover, by fitting the fitting projection portions  29  and the fitting recess portions  30  with each other, a relative rotation between the front side stator member  21 A and the rear side stator member  21 B is prevented. Further, in sections between the parts where the fitting projection portion  29  and the fitting recess portion  30  are fitted with each other, caulking S is performed at two sites each. That is, in the present embodiment, the front side stator member  21 A and the rear side stator member  21 B are joined by fitting the fitting projection portions  29  and the fitting recess portions  30  with each other and the caulking S.