Abstract:
A solenoid coil assembly having a first component member that is configured to support a coil and has a pair of terminal pins. The terminal pins are positioned for attachment to a structure such as a circuit board or lead frame. The first component member has pins for ultrasonic staking to a second component member. The second component member covers the first component member and the first and second component members provide an area for receiving and mounting the solenoid coil assembly to a valve assembly. The solenoid coil assembly positions first component member including the coil about the valve assembly.

Description:
TECHNICAL FIELD 
     The present invention relates to a solenoid coil assemblies and more particularly, to a design configuration and method for securing solenoid coils relative to corresponding valve assemblies. 
     BACKGROUND OF THE INVENTION 
     Solenoid actuated valves are manipulated in response to an electromagnetic force of the solenoid coil. The electromagnetic force positions movable valve elements in various manners. An integral part of these devices are the air gaps provided in the electromagnetic circuit of the solenoid. A primary (working), air gap is generally provided between the movable armature and a first non-moving ferromagnetic element. The first non-moving ferromagnetic element generally comprises an integral part of the associated valve&#39;s structure. Secondary (parasitic) air gaps are generally provided between the movable armature and other non-moving ferromagnetic elements. The other non-moving ferromagnetic elements generally comprise integral parts of the actuator. When the solenoid is energized, the coil establishes magnetic flux in the ferromagnetic elements which traverses all the air gaps. The size of the air gaps is an important factor in determining the operational characteristics of the device. 
     Variations in the magnetic flux transfer properties of solenoid actuated valves may be particularly intolerable depending upon the nature of the application within which the device operates. Efficient designs must prevent magnetic flux losses created by undesirable conditions such as inordinately large secondary air gaps. 
     In some applications a solenoid actuator may be incorporated with a control mechanism by directly attaching the solenoid&#39;s coil terminal pins to a circuit board. In this type of device, the solenoid actuated valve comprises two subassemblies. One subassembly carries the actuator&#39;s coil with its terminals soldered to the control circuit board. The other subassembly carries the valve body. When the two subassemblies are mated together, some facility is generally provided for allowing the coil to move relative to its subassembly and into position for receipt onto the valve body. However, since the coil is preferably soldered to the circuit board prior to mating of the two subassemblies, connection of the coil and valve body may undesirably stress the soldered connections between the coil&#39;s terminal pins and the circuit board due to, for example, slight mislocations of the positioning of both subassemblies from normal manufacturing tolerances. 
     Provisions that allow movement of the coil for assembly purposes may also become undesirable when the solenoid actuated valve is placed in service. Coil movement may be induced by vibratory conditions that exist in the solenoid actuated valve&#39;s operating environment. Vibration induced coil movement also transfers loads to the soldered terminal pin connection. 
     Therefore, a solenoid actuated valve&#39;s design should prevent this condition from occurring. Accordingly, a solenoid actuated valve design is required that: provides ease of assembly and disassembly, exhibits good magnetic flux transfer characteristics, and is able to withstand harsh vibratory environments. 
     SUMMARY OF THE INVENTION 
     It is a goal of the present invention to provide a solenoid actuated valve that: is constructed from two subassemblies that are easily assembled and disassembled, exhibits good magnetic flux transfer characteristics, and is able to withstand harsh vibratory environments. In accordance with this goal, a solenoid actuated valve is provided that is designed according to concepts that are equally applicable to normally closed valves, normally open valves, multi-function valves, and other typical related types of valves. The solenoid actuated valve includes a first subassembly that carries a coil having its terminal pins attached to a structure such as a circuit board or rigid lead frame. A second subassembly is provided for mating with the first subassembly. The first and second subassemblies carry the valve body which may be further attached to a valve housing utilized for directing the flow of hydraulic fluid. 
     In accordance with a preferred embodiment of the present invention, a first subassembly includes a solenoid spool including the coil and the second a case for surrounding the spool. 
     The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of the coil assembly secured to a valve assembly; 
     FIG. 2 is a side view of the coil assembly; 
     FIG. 3 is a view along the lines  3 — 3  of the FIG. 2 embodiment; 
     FIG. 4 is a view along the lines  4 — 4  of the FIG. 3 embodiment; 
     FIG. 5 is a view along the lines  5 — 5  of the FIG. 3 embodiment; 
     FIG. 6 is a cross-section a view of the coil assembly; 
     FIG. 7 is a perspective view of a spool assembly; 
     FIG. 8 is an end view of the coil assembly depicted in FIG. 7; 
     FIG. 9 is a perspective view of an alternative embodiment of the present invention; 
     FIG. 10 is a side view of a fixture assembly and a portion of the coil assembly process; and 
     FIG. 11 is an end view of an alternative embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1-7, a coil assembly  10  constructed in accordance with the present invention is illustrated. Assembly  10  has a spool assembly  12  and an outer case  14 . Spool assembly  12  is configured and dimensioned to be received and engaged within outer case  14 . The spool in spool assembly  12  is constructed out of a durable, light-weight, nonconductive, easily molded material such as plastic. The outer case  14  is constructed out of a ferromagnetic material, which helps to align and direct the magnetic flux generated by assembly  10 . In an exemplary embodiment, the spool in spool assembly  12  is configured to receive a winding or coil of wire  18 . Coil  18  generates a magnetic flux when a current is passed through it. A pair of terminals  20  for securement to a circuit board (not shown) are secured to spool assembly  12  and winding  18 . 
     Spool assembly  12  is configured to have an inner through opening  22  for receiving and engaging a portion of a valve assembly to which coil assembly  10  is mounted. Spool assembly  12  has a spool assembly guide end  24  and a spool assembly securement end  26 . The configuration of the spool and ends  24  and  26  define a channel or receiving area  28  into which coil  18  is wound. 
     In addition, a guide opening  30  is positioned on spool assembly guide end  24 . Guide opening  30  serves as a fastening feature to hold the spool in a turning apparatus which will rotate the spool to allow the wire to be wrapped around the spool winding bay creating a coil  18 . 
     The outside diameter of spool assembly guide end  24  and securement end  26  are slightly smaller than the inside diameter of outer case  14 . This allows spool assembly  12  to be inserted and engaged within case  14 . 
     Case  14  has an opening  32  at one end and an opening  34  at the other. Opening  32  has an inside diameter that is slightly larger than the outside diameter of guide end  24  and securement end  26  of spool assembly  12 . 
     In an exemplary embodiment, the sidewalls of opening  32  are chamfered to provide for ease of insertion of spool assembly  12  into case  14 . Opening  34  of case  14  is smaller than opening  32  and similar in size to opening  22  of spool assembly  12 . Therefore, spool assembly  12  must be inserted into case  14  through opening  32 . Case  14  is configured to have an inner annular receiving area  36  defined by the outer walls of case  14  and the walls of opening  34 . Inner annular receiving area  36  receives and engages securement end  26  of spool assembly  12  as it is inserted into case  14 . 
     Securement end  24  has an engagement opening  38 . Engagement opening  38  is slightly larger than inner opening  22  of spool assembly  12 . Engagement opening  38  is large enough to accommodate opening  34  and the sidewalls of case  14  which define opening  34 . 
     In an exemplary embodiment, securement end  26  is configured to have a pair of staking pins  42  which protrude outwardly from an engagement surface of securement end  26 . Accordingly, and as securement end  26  is inserted into inner annular receiving area  36 , staking pins  42  pass through a pair of openings  44  in case  14 . In an exemplary embodiment, openings  44  are round, however, and as applications may require openings  44  may be of any configuration matching pins  42 . The staking pins  42  protrude outwardly from securement end  26  a sufficient amount to allow staking pins  42  on spool to pass through case openings  44  and protrude outwardly from case  14  a sufficient amount to allow for the ultrasonic staking of pins  42  on spool assembly  12  to case  14 . As illustrated by the dashed lines in FIG. 6 staking pins  42  have an initial un-staked configuration whereby the thickness of pin  42  is slightly smaller than the size of opening  44 . Once pins  42  have been ultrasonically staked, the thickness of pins  42  is slightly larger than the size of opening  44  and the high of pin  42  is reduced. Accordingly, this allows spool assembly  16  to be fixedly secured to case  14 . Of course, and as applications may require, the number of staking pins and their positions may vary. 
     As another alternative spool assembly  16  is inserted and secured to case  14  in a quick and efficient manner which provides a low cost and efficient manufacturing process for manufacturing coil assembly  10 . 
     In an exemplary embodiment, where the outside diameter of securement end  26  is configured to have a raised engagement surface  46  for frictionally engaging the inner surface of case  14 , a portion of raised engagement surface  46  can be configured to facilitate the insertion of spool assembly  12  within outer case  14 . 
     Once spool assembly  16  is fully inserted within case  14 , and staking pins  42  protrude through case openings  44 , the spool assembly is secured to the case using ultrasonic staked pins. This allows spool assembly  16  to be inserted and secured to case  14  in a quick and efficient manner which provides a lower cost and more efficient manufacturing process for coil assembly  10 . 
     In addition, and after spool assembly  16  is fully inserted into case  14  a receiving area  45  is defined by guide end  24  and the outer walls of case  14 . Receiving area  45  is configured to receive a portion of a valve assembly (FIG.  1 ). 
     As an alternative, and referring now to the dashed lines in FIG. 6, case  14  is configured to have an interference case indentation  60 , or a pair of indentations, which is biased generally in the direction of arrow  62 . Accordingly, and as spool assembly  16  is inserted into opening  32 , securement end  24  forces indentation and securement end  24  slides by interference indentation  60  until it has passed indentation  60  and indentation  60  is received within an opening  64  of spool assembly  12 . Accordingly, indentation  60  provides for an interference fit of spool assembly  12  within case  14 . As an alternative, stakes  42  may also be employed to secure spool assembly  12  within case  14 . 
     Referring now in particular to FIGS. 5,  7  and  10  the positioning of guide hole  30  with respect to terminals  20  provides for an identification of the type of coil being used in the assembly process. Accordingly, and referring to the position of guide hole  30  with respect to terminals  20 , an individual can quickly determine what type of coil is being inserted into outer case  14 . For example, a guide hole positioned as in FIG. 5 will identify a type of coil assembly. 
     Referring now to FIG. 10, a fixture assembly  70  is illustrated. Fixture assembly  70  provides a supporting base for coil assembly  10 . Fixture  70  has a coil supporting fixture base  72 , a guiding diameter portion  74  and a guide hole pin  76 . 
     Guiding diameter portion  74  is configured to have an outside diameter slightly smaller than the inside diameter of opening  32  of case  14 . Guide hole pin  76  is positioned on the outer surface of guiding diameter portion  74  and it is configured to have an outside diameter slightly smaller than the inside diameter of guide hole  32 . 
     Accordingly, and during the assembly process of coil assembly  10 , outer case  14  and guide hole  32  can be positioned over guiding diameter portion  74  and guide hole pin  76  respectively. 
     The configuration of coil assembly  10  provides a receiving area  78  within opening  32  of case  14 . The volume of receiving area  78  is slightly larger than the outside configuration of guiding diameter portion  74 . Therefore, and as coil assembly  10  is positioned over fixture  70  coil assembly  10  is supported by coil supporting fixture  72  and guiding diameter portion  74 . 
     Fixture  70  supporting the coil assembly will be guided using the inner diameter of the case. Guide pin  76  will be protruding from this fixture and is located so that the guide hole on the spool assembly falls over the pin thus fixing its positioned angularly relative to the center axis of the coil. 
     This will fixedly positioning coil assembly  10  with respect to a coil board or circuit board  80  having apertures  82  into which the terminals of the coil assembly enter and are wave soldered to. 
     The fixtures are made using the angular position of the guide hole relative to the two protruding terminals. (FIGS. 4,  5  and  11 ) Therefore, when the coil assembly is placed on a bottom fixture which orients the coil using the guide hole, if the incorrect coil assembly is being inserted the resulting position of the terminals will not coincide with the correct terminal hole position on the circuit board. Therefore, the type of coil assembly will be easily identifiable and the manufacturer will be able to identify if the correct coil assembly has been inserted. 
     As an alternative, and as illustrated by the dashed lines in FIGS. 5 and 10, another option is to place two guide holes on the spool with a specific and unique radial angular position. In addition, a pair of guide hole pins are positioned on the surface of guiding diameter portion  74 . In this embodiment, the two pins on the fixture are designed to accept a specific coil assembly must have the same radial angular position as the coil guide holes. 
     In this embodiment, the coil assembly can be distinguished without any need to the coil board  80  as the coil assembly will not properly sit upon fixture  70 . 
     In addition, and as an alternative, coil supporting fixture  72  is configured to have a plurality of guiding diameter portions  74  and guide our pin  76  for a receiving and supporting a plurality of coil assemblies for securement to a circuit board. 
     These configurations provide a more efficient manufacturing process for assembly  10 . 
     Referring now in particular to FIG. 1, coil assembly  10  is shown to be secured to a valve assembly  50 . Valve assembly  50  has a flange portion  52  which has an outside diameter slightly smaller than the inside diameter of opening  32  of case  14 . Flange portion  52  is received and engaged within receiving area  45 . As an alternative, the inside diameter of opening  32  can be configured to be slightly smaller than the outside diameter of flange  52  and case  14  is constructed out of a material having flexible characteristics such that opening  32  will accommodate flange  52  as it is inserted into opening  32 . This configuration will provide for a contact frictional engagement between the inner surface of opening  32  and flange  52 . As an alternative, the sidewalls of opening  32  are configured to have a smaller thickness so as to allow the sidewalls of opening  32  to flex outwardly as spool assembly  12  is inserted into case  14 . 
     As yet another alternative, a plurality of slots  31  are located on case  14 . The positioning of slots  31  define a plurality of case members  33  which will be able to cantilever outward as spool assembly  12  is inserted into case  14 . In addition, case members  33  will also cantilever outward in response to the insertion of a flange portion of a valve assembly being inserted into opening  32 . 
     As yet another alternative, and referring now to FIG. 9, the inner surface of opening  32  is configured with a feature such as a plurality of grooves or indentations that will mate with a corresponding plurality of projections along the periphery of flange  52 . Other alternate features can be slots and/or thin walls on case  14  at opening  32  to reduce the insertion forces required to push coil assembly over valve assembly flange portion  52 . 
     Referring back now to FIG. 1, as coil assembly  10  is mounted to valve  50 , the configuration of coil assembly  10  provides for a direct contact between the surface of flange  52  and the surface of guide end  24 . In this position, the coil and magnetic flux generated thereby is positioned to affect the movement of a plunger within valve  50 . In addition, the configuration of coil assembly  10  provides a rigid securement of valve assembly  50  to coil assembly  10 . 
     Opening  64  also provides a means for securing terminals  20  to a winding of coil  18 . This feature also allows the spool to have relatively uniform walls minimizing the amount of physical distortion on the part after it cools out of the mold. 
     The non-integral coil assembly to a valve of the instant application is a unique valve to coil interface that offers flexibility in modulator assembly for electronic control unit (ECU). In an exemplary embodiment, the ECU is comprised of, but not limited to, an electronic control circuit, housing, coil board or flex circuit, and coil assemblies to the hydraulic control unit (HCU). The HCU is comprised of, but not limited to, the hydraulic block, circuit, components, pump and valves, electrical and magnetic connections. The bottom portion of the coil magnetic circuit is enclosed with the valve of flange offering a more compact coil to valve assembly package. Each coil assembly is individually packaged so that it can be interchanged between the different types of valves in the HCU. The spool assembly is inserted into the case that covers all of the coil assembly magnetic circuit areas except for the bottom. The case is attached to the spool assembly using ultrasonic staking or interference fit to special indentations on the case. A hole in the spool flange and its angular relationship to the terminals is what identifies the type of coil in the modulator assembly and associated assembly processes. 
     The design of the coil assembly of the instant application allows for reduced actuator packaging, where the bottom portion of the magnetic circuit is integrated as part of the valve flange, the coil assembly is individually packaged and self-contained for interchangeability among valves and case to valve interface can be a slip fit, low interference, or interference depending on modulator assembly and/or serviceability requirements 
     This design also reduces coil and actuator assembly package mass and volume. There is also cost reduction due to the reduction of components. There is also flexibility in the assembly of the coils as they are individually packaged for interchangeability with the modulator and can be adapted to various levels of assembly and disassembly scenarios. 
     The coil assembly of the instant application allows for slip to full press insertion forces to be applied for positioning the coil assembly over valves. Zero effort to non-disassemble conditions can be handles were serviceable and nonserviceable requirements must be met with magnetic and electrical ECU to HCU connections. 
     Since the coil is not integrated into the valve, high valve to modulator insertion forces can be applied without deleterious effects. This allows for accommodation of valve press to retain and or seal designs for a valve to modular assembly. 
     While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.