Abstract:
Provided are a solenoid valve which is configured such that the valve body is not deformed when a retainer is mounted and which can be easily assembled, and a method of manufacturing the solenoid valve. A solenoid valve is provided with a valve body inside which a spool is provided so as to move in an axial direction, a solenoid section which is mounted to one end of the valve body in the axial direction thereof, and a retainer which is mounted to the other end of the valve body in the axial direction thereof. The retainer is fixed by a staking section which is provided to an end of the valve body in the axial direction thereof and staked in the axial direction.

Description:
TECHNICAL FIELD 
     The present invention relates to a spool type solenoid valve preferably applied for an oil controlling for an oil pressure device and the like. 
     BACKGROUND ART 
     As a conventional solenoid valve, as shown in the following Patent Document 1, there has been provided a solenoid valve wherein a retainer is inserted into a valve body, a portion which the valve body overlapped with the retainer is made as a thin wall, the retainer is fixed by caulking the thin wall portion in a radius direction. 
     For the solenoid valve having such constitution, the inner circumferential wall of the valve body is sometimes deformed due to the collapse of the valve main body in the radius direction because a force is applied to the radius direction when caulking the retainer. As a result, there is a case to become a cause of increasing hysteresis because smooth operation of a spool sliding to the axial direction at the inside of the valve body is inhibited, the spool will not be moving in the worst case. 
     Also, for the solenoid valve in the Patent Document 1, a screw cutting is performed in the valve body in order to fix the retainer and it is necessary to perform screw-driving to a predetermined position. Thus, assembling property is insufficient and further, there is a problem that a manufacturing cost becomes higher when performing a threading process because there is a large number of man-hour for producing components. 
     Prior Art Literatures 
     Patent Document 
     Patent Document 1: Japanese Unexamined Patent Publication No. 2000-104847 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     The present invention has been made by considering the above problems, a purpose thereof is to provide a solenoid valve which does not cause a deformation in a valve body when mounting a retainer and which can be easily assembled, and also a method for manufacturing thereof. 
     Means for Solving the Problem 
     In order to achieve the above purpose, a solenoid valve according to the present invention comprises 
     a valve body in which a spool is provided so as to move in an axial direction, 
     a solenoid portion provided at one axial end of said valve body, 
     a retainer provided at the other axial end of said valve body, wherein 
     a caulking portion provided at the axial end of the valve body is caulked from the axial direction so that the retainer is fixed. 
     By making such constitution, because a pressure force on caulking the retainer acts only in the axial direction (the pressure force does not act in the radius direction of the valve body), the pressure force does not act on a sliding portion of the spool of the valve body, and deformation is not achieved to the sliding portion of the spool in the valve body. Therefore, a sliding motion of the spool at the inside of the valve body is not inhibited, and the spool can be moved smoothly in the axial direction. 
     In the present invention, preferably, a groove for inserting a caulk receiving jig is formed near said caulking portion in the axial direction. 
     By making such constitution, the caulk receiving jig can be arranged to the groove when caulking the retainer. Therefore, the pressure force which acts along the axial direction can be applied to the caulk receiving jig when caulking the retainer, and the valve body is not deformed in the axial direction of the valve body. Namely, it preferably enables to prevent the valve body from deforming, and the sliding movement of the spool which is axially movably arranged at the inside of the valve body is not inhibited. 
     In the present invention, preferably, said retainer is comprised of a cylindrical body, a flange portion projecting to an outer radius direction is formed at one opening end of the axial direction of said cylindrical body, the caulking portion of said valve body is comprised of a caulking piece projecting from the other axial end of said valve body. 
     By making such constitution, it enables to caulk the flange portion as covered by the caulking pieces according to contacting the flange portion of the retainer at the inside of the radial direction of caulking pieces in the valve body. Therefore, a process for a solenoid valve assembly can be simplified and it becomes more efficient, because it is not necessary to perform a screw cutting to the valve body and the retainer can be fixed to the valve body. 
     Also, in order to achieve the above purpose, a method for manufacturing solenoid valve of the present invention comprises steps of, 
     providing a caulking portion at the axial end portion of a valve body, 
     forming a groove for inserting a caulk receiving jig near said caulking portion in the axial direction, 
     arranging a spool as axially movably at the inside of the valve body, 
     mounting a solenoid portion at one axial end of said valve body, 
     arranging said caulk receiving jig at said groove, and 
     mounting the retainer at the other axial end of said valve body by caulking said caulking portion from the axial direction to the retainer. 
     By the method for manufacturing solenoid valve having such constitution, the valve body is not deformed in the radius direction of the valve body, because a pressure force acts only in the axial direction when caulking the retainer (the pressure force does not act in the radius direction of the valve body) and also the pressure force can be produced to the caulk receiving jig when caulking the retainer. Therefore, a sliding motion of the spool which is arranged axially movably at the inside of the valve body is not inhibited. 
     Also, it is not necessary to perform a screw cutting to the valve body, because the retainer can be fixed to the valve body by caulking from the axial direction with the caulking portion. Therefore, the process for a solenoid valve assembly can be simplified and it becomes more efficient. 
     Effects of the Invention 
     According to the present invention, it is possible to provide a solenoid valve which is configured such that the valve body is not deformed when a retainer is mounted and which can be easily assembled, and also a method for manufacturing thereof. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross sectional view of a solenoid valve according to one embodiment of the present invention; 
         FIG. 2A  is a main portion cross sectional view of a retainer in the solenoid valve shown in  FIG. 1  before caulking; 
         FIG. 2B  is a main portion cross sectional view of a retainer in the solenoid valve shown in  FIG. 1  when caulking; and 
         FIG. 3  is a main portion enlarged view of  FIG. 2B . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the present invention will be explained on the basis of embodiments shown in drawings.  FIG. 1  is a cross sectional view of a solenoid valve according to one embodiment of the present invention,  FIG. 2A  is a main portion cross sectional view of a retainer in the solenoid valve shown in  FIG. 1  before caulking,  FIG. 2B  is a main portion cross sectional view of a retainer in the solenoid valve shown in  FIG. 1  when caulking,  FIG. 3  is a main portion enlarged view of  FIG. 2B . 
     As shown in  FIG. 1 , a solenoid valve  10  according to an embodiment of the present invention is a spool type solenoid valve to control an oil pressure of, for example, an automatic transmission of vehicle. 
     The solenoid valve  10  comprises a solenoid portion (linear solenoid)  20  as an electromagnetic drive portion, a valve body  40  as a valve portion and a retainer  45 . The solenoid portion  20  is mounted at one end along the axial direction Z of the valve body  40 , and the retainer  45  is mounted at the other end along the axial direction Z of the valve body  40 . 
     The solenoid portion  20  comprises a rod  24 , a plunger  23  and a coil  22  at the inside of a case  21 . 
     The case  21  is configured with a cylindrical body having a bottom, and the rod  24  is arranged at roughly at center of the case  21  along the axial direction Z. The rod  24  contacts with a spool  60  at one end of the axial direction Z, the spool  60  is arranged at the inside of the valve body  40 . 
     The plunger  23  which is integrally movable with the rod  24 , is arranged at an outer circumferential surface of the rod  24 . Also, the coil  22  is arranged at an outer circumferential side of the plunger  23 , and the coil  22  generates a magnetic field in a desired direction with a desired strength according to a controlling current provided from a control circuit (not shown). Although a material of the case  21  is not particularly limited, it is manufactured by using a magnetic material, for example, SPCC, SPCE, SUY and the like. 
     The valve body  40  comprises a spring  42  and the spool  60  at the inside of a valve sleeve  41 . 
     The valve sleeve  41  is configured with a cylindrical body, the spring  42  and the spool  60  are arranged at roughly at center of the valve sleeve  41  along the axial direction Z. The spool  60  contacts with the spring  42  at one end of the axial direction Z, and contacts with the rod  24  at the other end of the axial direction Z. 
     As openings penetrating a circumferential wall of the valve sleeve  41 , an inlet port  51 , an outlet port  52 , a feedback port  53  and a first drain port  54  are formed on the valve sleeve  41 . Note that, the inlet port  51 , the outlet port  52 , the feedback port  53  and the first drain port  54  are formed as a plural respectively, toward a circumferential direction. 
     The inlet port  51  is a port to which a controlling fluid (for example, hydraulic oil) provided by a pump from a tank which are not shown. 
     The outlet port  52  is a port supplying a fluid which is controlled by a desired pressure to a requested fluid portion (load) of an automatic converter which is not shown. 
     The outlet port  52  and the feedback port  53  are communicating through at an external portion of the solenoid valve  10 , and some part of the controlling fluid flown from the outlet port  52  flows into the feedback port  53 . 
     The first drain port  54  is a port which outlets the controlling fluid at the outlet port  52  side to a drain. 
     The spring  42  is mounted between the spool  60  and an inner circumferential surface of a retainer  45  which is mentioned below along the axial direction Z, and presses the spool  60  in the axial direction Z. 
     The spool  60  is movably arranged at roughly at center of the valve sleeve  41  along the axial direction Z, and is constituted by a spool axis  61  and a first to third lands  63  to  65  which are formed as cylindrically. 
     The first to third lands  63  to  65  are formed integrally with the spool axis  61  from an end portion of the spring  42  side of the spool  60  along the axial direction Z with predetermined spaces sequentially. 
     Outer diameters of the first to third lands  63  to  65  are larger than an outer diameter of the spool axis  61 . Also, although the outer diameters of the fist land  63  and the second land  64  are about the same, the outer diameter of the third land  65  is smaller compared to the outer diameters of the first land  63  and the second land  64 . 
     A feedback chamber  67  is formed between the second land  64  and the third land  65  at the inside of the valve sleeve  41 . Because there is an outer diameter difference between the second land  64  and the third land  65 , the areas to which the controlling fluid fed back by the feedback chamber  67  that acting to the spool  60  are different. As a result, a desired output pressure Pc can be obtained by a balance of three forces which are a feedback force generated by the difference of the area (outer diameter difference between the land  64  and the land  65 ), a spring force by the spring  42  and an electromagnetic force which changes by the volume of current. For example, in case the controlling valve is the type that an output pressure decreases as an electric current supplied to the solenoid portion  20  is increased, the balance of three forces can be shown by the following formula (1);
 
[spring force]=[output pressure(=feedback force generated at outer diameter difference of lands)]+[electromagnetic force]  (1).
 
     Also, in case the controlling valve is the type that an output pressure increases as an electric current supplied to the solenoid portion  20  is decreased, the balance of three forces can be shown by the following formula (2);
 
[spring force]+[output pressure(=feedback force generated at outer diameter difference of lands)]=[electromagnetic force]  (2).
 
     Along the axial direction Z, one end of the spool  60  contacts with the spring  42  and the other end of the spool  60  contacts with the rod  24 . As a result, as well as a pressure force of the controlling fluid in the feedback chamber  67  (feedback force), a pressure force of the spring  42  (spring force) and a pressure force (electromagnetic force) by the movement of the plunger  23  via the rod  24  are transmitted to the spool  60 . The spool  60  slides at the inside of the valve sleeve  41  in the axial direction Z by these pressure forces. 
     In the solenoid valve  10  having such constitution, the spool  60  rests at a position where a pressure force (spring force) generated by the spring  42 , a pressure force (electromagnetic force) which the plunger  23  presses the spool  60  with a magnetic suction force of a magnetic field generated by an electric current supplied to the coil  22  and a pressure force (feedback force) generated by a pressure force of the controlling fluid in the feedback chamber  67  are balanced. Precisely, although it is balanced at a statically balanced position, it is practically controlled by opening and shutting the inlet port  51  and the first drain port  54  frequently. 
     A position of the spool  60  in the valve sleeve  41  is controlled by the above mentioned force, and the inlet port  51  and/or the first drain port  54  are opened and shut as desired status. 
     Also, the amount of the controlling fluid which flows from the inlet port  51  to the outlet port  52  is determined by an opening amount of the inlet port  51 . The opening amount of the inlet port  51  is determined by a position of the spool  60  at the inside of the valve sleeve  41 . 
     The amount of the controlling fluid which flows from the inlet port  51  to the outlet port  52  is increased by changing a position of the spool  60  at the inside of the valve sleeve  41  and enlarging the opening amount of the inlet port  51 . Also, the amount of the controlling fluid which flows from the inlet port  51  to the outlet port  52  is decreased by reducing the opening amount of the inlet port  51 . 
     Similarly, the amount of the controlling fluid which flows from the outlet port  52  to the fist drain port  54  is determined by the opening amount of the first drain port  54 . The amount of the controlling fluid which flows from the outlet port  52  to the first drain port  54  is increased by changing a position of the spool  60  at the inside of the valve sleeve  41  and enlarging the opening amount of the first drain port  54 . Also, the amount of the controlling fluid which flows from the outlet port  52  to the first drain port  54  is decreased by reducing the opening amount of the first drain port  54 . 
     Namely, in the solenoid valve  10  of the present embodiment, in case that the output pressure Pc (=feedback force generated by outer diameter difference of the land) is smaller than a desired pressure, the spool  60  moves to the solenoid portion  20  side along the axial direction Z to open the inlet port  51 . As a result, an inlet pressure Po is provided to the inside of the valve body  40  through the inlet port  51 . On the other hand, in case that the outlet pressure Pc is larger than a desired pressure, the spool  60  moves to the spring  42  side along the axial direction Z and the first drain port  54  is caused to open so that the pressure force Pc is emitted through the first drain port  54 . 
     A caulking portion  70  is formed at the end of a retainer side along the axial direction Z of the valve sleeve  41 . The caulking portion  70  comprises a caulking piece  71  which extends along the axial direction Z from the valve sleeve  41 , and a groove  72  is formed near the axial direction Z of the caulking portion  70 . 
     The caulking piece  71  may be formed on the whole circumference along a circumferential direction of the valve sleeve  41 , or may be formed as intermittently at predetermined spaces along the circumferential direction of the valve sleeve  41 . Also, it may be formed as intermittently at irregularly spaces along the circumferential direction of the valve sleeve  41 . 
     The groove  72  may be formed on the whole circumference along the circumferential direction of the valve sleeve  41 , or may be formed at predetermined spaces along the circumferential direction of the valve sleeve  41 . Also, it may be formed as intermittently at irregularly spaces along the circumferential direction of the valve sleeve  41 . 
     As shown in  FIG. 2A , although a width W 1  along the axial direction Z of the caulking piece  71  is not particularly limited, 0.5 to 3.0 mm is preferable and 1.5 to 2.0 mm is further preferable. 
     Also, a width W 2  of the axial direction Z from the groove  72  to the caulking piece  71  is preferably 0.5 mm or more, and 1.0 to 4.0 mm is particularly preferable. 
     Also, a width W 3  along the axial direction Z of the groove  72  is preferably 1.5 mm or more, and 2.0 to 3.0 mm is particularly preferable. 
     Also, for a depth D 1  along the inside of a radius direction of the groove  72  from the outer diameter of the caulking piece  71 , a depth which is available to receive a pressure force certainly that acts only in the axial direction Z when calking the retainer  45  is preferable, and 1.0 to 3.0 mm is particularly preferable. 
     Also, a width W 4  of the axial direction Z from the groove  72  to the first drain port  54  is not particularly limited. 
     Although a material of the valve sleeve  41  is not particularly limited, it is manufactured by using, for example, aluminum and the like. 
     The retainer  45  is configured with a cylindrical body having a bottom, a flange portion  45 F which projects to the outside of a radius direction is formed at one opening end along the axial direction Z of the cylindrical body. Also, a second drain port  55  is formed at the other end portion (bottom portion) along the axial direction Z of the cylindrical body. The spring  42  is mounted between the other end portion (bottom portion) along the axial direction Z of the cylindrical body and the spool  60 , and the spring  42  presses the spool  60 . 
     The flange portion  45 F may be formed on the whole circumference along the circumferential direction of the retainer  45 , or may be formed at predetermined spaces along the circumferential direction of the retainer  45 . Also, it may be formed as intermittently at irregularly spaces along the circumferential direction of the retainer  45 . 
     Although a material of the retainer  45  is not particularly limited, it is manufactured by using, for example, iron and the like. 
     As shown in  FIG. 2B , when caulking the retainer  45 , the flange portion  45 F is caused to contact with the inner side of the radius direction of the caulking piece  71 . After this, a caulk receiving jig  76  is arranged to the groove  72 , and the flange portion  45 F is caulked to be covered by the caulking piece  71  by applying a force from the axial direction Z to the caulking piece  71  with use of caulking tool  75  so that the retainer  45  is fixed to the valve sleeve  41 . 
     The calking tool  75  is configured with a cylindrical body having a bottom, a tapered surface  77  is formed at the inside of the radius direction of one opening end along the axial direction Z of the cylindrical body. The retainer  45  is fitted to the inner surface  78  of a cylindrical body of the caulking tool  75 , and the caulking piece  71  is bent to the inner side of the radius direction along the tapered surface  77  by pressing the caulking tool  75  to the axial direction Z so that the caulking piece  71  contacts with the tapered surface  77 . Deformation of the valve sleeve  41  is prevented, because a pressing force of the caulking tool  75  is received effectively by the caulk receiving jig  76 . 
     Also, as shown in  FIG. 3 , the pressing force of the caulking tool  75  acts to a position where the flange portion  45 F contacts to the caulking piece  71 . In order for receiving the pressing force effectively, it is preferable to make the depth D 1  along the inside of the radius direction of the groove  72  deeper than the position where the flange portion  45 F contacts with the caulking piece  71 . 
     In the solenoid valve  10  configured like this, the coil  22  generates a magnetic field having desired strength and desired direction by being supplied an electric current from a controlling circuit which is not shown in the drawings to the coil  22  of the solenoid portion  20 , and the plunger  23  is moved by the magnetic suction force of the magnetic field. 
     The spool  60  moves to the spring  42  side in the valve sleeve  41  of the valve body  40  by increasing the amount of the electric current supplied to the coil  22  and making a large magnetic suction force acts on the plunger  23 . 
     When the spool  60  moves to the spring  42  side in the valve sleeve  41 , the inlet port  51  closes and the first drain port  54  is caused to open. Therefore, the controlling fluid does not flow from the inlet port  51  to the outlet port  52 , and the controlling fluid flows from the outlet port  52  to the first drain port  54 . As a result, the pressure force Pc of the controlling fluid flown out from the outlet port  52  is decreased. 
     On the other hand, the spool  60  moves to the solenoid portion  20  side in the valve sleeve  41  by reducing the amount of the electric current supplied to the coil  22  and making the magnetic suction force which acts to the plunger  23  decreases. 
     When the spool  60  moves to the solenoid portion  20  side in the valve sleeve  41 , the first drain port  54  closes and the inlet port  51  is caused to open. Accordingly, the controlling fluid flows from the inlet port  51  to the outlet port  52 , and the controlling fluid does not flow from the outlet port  52  to the first drain port  54 . As a result, the pressure force Pc of the controlling fluid flown out from the outlet port  52  is increased. 
     Namely, in the solenoid valve  10  of the present embodiment, the pressure force Pc of the controlling fluid which is output from the outlet port  52  decreases as the electric current supplied to the coil  22  is increased, and the pressure force Pc of the controlling fluid which is output from the outlet port  52  increases as the electric current supplied to the coil  22  is decreased. 
     In the solenoid valve  10  having such constitution, by controlling the electric value supplied to the coil  22 , the pressure force of the controlling fluid flown out from the outlet port  52  is controlled according to the adjustment of the pressing force of the solenoid portion  20  to the spool  60  and the adjustment of a valve open-shut of the valve body  40 . 
     Note that, the present invention is not limited to the above mentioned embodiment, it can be modified variously within the scope of the present invention. For example, arrangement for the inlet port  51 , the outlet port  52 , the feedback port  53  and the first drain port  54  in the valve body  40  are not limited to the example shown in  FIG. 1 , it may be a solenoid valve wherein the outlet port  52  and the feedback port  53  are changed. 
     In the solenoid valve having such constitution, a relation of the electric current supplied to the coil of the solenoid portion and a pressure force of the controlling fluid becomes opposite to the above mentioned solenoid valve  10 . Namely, in this solenoid valve, the pressure force Pc of the controlling fluid which is output from the outlet port increases as the electric current supplied to the coil  22  is increased, and the pressure force Pc of the controlling fluid which is output from the outlet port decreases as the electric current supplied to the coil is decreased. Briefly, the solenoid valve is different from the solenoid valve  10  shown in  FIG. 1  and has an opposite characteristic. 
     Also, in the above mentioned embodiment, the retainer  45  is caulked after arranging the caulk receiving jig  76  to the groove  72 , however, the retainer  45  may be caulked without arranging the caulk receiving jig  76  to the groove  72 .