Hydraulic control apparatus

Abstract: In a solenoid valve 3, a coil 4 is disposed on the electronic control unit 2 side, and is resin injection molded integrally to a resin case 5 housing a circuit board 9 on which electronic components 19 and 19' are mounted. Before a hydraulic control unit 1 and electronic control unit 2 are connected, an end of a connecting pin 10 for the coil 4 is electrically connected by soldering or other means to wiring of circuit board 9, and a cover 20 of similar material is pressed to and welded with resin case 5 to assure a waterproof structure around the circuit board 9. Finally, a magnetic member 6 or magnetic plate 28 constituting part of a magnetic circuit provided separately to or integrally molded with resin case 5 is fastened by a bolt 21 to unitarily connect both units.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control apparatus integrally comprising a hydraulic control unit containing a solenoid valve, and an electronic control unit for controlling the hydraulic control unit, said hydraulic control apparatus being suitable for use as, for example, the hydraulic control apparatus of an antilock brake control system in a motor vehicle. 2. Description of the Related Art When antilock brake control systems were first introduced in automobiles, the hydraulic control unit and electronic control unit were usually installed as separate units connected by a cable. As shown in DE-A-41 00 967, family document of Japanese Tokuhyo No. H5-505446 (1993-505446), a hydraulic control apparatus integrally comprising a hydraulic control unit containing plural solenoid valves, and an electronic control unit for controlling the hydraulic control unit, was subsequently developed. This apparatus enabled cost and size reductions by eliminating the connector cable and associated connectors, and enabling the hydraulic control apparatus to be installed to a vehicle in a single operation. This is shown in Fig. 13 of the present patent specification and described below. An assembly comprising valve block 105 and valve dome 110 corresponds to the hydraulic control unit of the present specification. An assembly comprising electronic components 120 and 120' on a printed circuit board 119, a steel jacket 121 surrounding the outside of a coil 101- to create a magnetic field pattern, and a flexible molding 115 surrounding and securing these parts inside a cover 103, corresponds to the electronic control unit of the present specification. In a hydraulic control apparatus integrally comprising such a hydraulic control unit and electronic control unit, the coils of the solenoid valves in the hydraulic control unit can be on the hydraulic control unit side or on the electronic control unit side. When the coils are disposed on the hydraulic control unit side, the coil and electronic control unit must be connected by means of a disconnectable connector structure while the solenoid valve components are all attached to the hydraulic control unit. The structure of the solenoid valve is therefore substantially that of a conventional independent hydraulic control unit. When the coils are disposed on the electronic control unit side, the coils and electronic circuitry can be directly connected. The problem in this case, however, is that the solenoid valve components become separated between the hydraulic control unit and electronic control unit. More specifically, because the magnetic circuit of the solenoid valves must be closed, a magnetic material must be provided both on the end of the coils connected to the hydraulic control unit and on the opposite end, -but this part cannot be preformed as part of the hydraulic control unit, and must be provided with the coils on the electronic control unit side. In the prior art example shown in Fig. 13, a steel jacket 121 subassembly is disposed as a magnetic member surrounding the coil 101, and must be connected to the printed circuit board 119. Note that there is no waterproof structure provided between the printed circuit board 119 and coil 101 at this stage. A lip seal 122 is therefore formed by covering these parts with a flexible molding 115 in a later process, resulting in a waterproof structure for the printed circuit board 119. Before these subassembly steps can be completed, however, the outside of the coil 101 must be insulated because the steel jacket 121 is connected to the coil 101. This means that while the task of connecting cables to connect the hydraulic control unit with the electronic control unit is eliminated, the waterproofing means at the connection surface and the task of subassembling the coil 101 before fastening the two units together are not eliminated. A further prior art is that disclosed in DE-A-4 432 165 and is concerned with a brake system for a vehicle, the system including electromagnetic valves. In particular it discloses a hydraulic control apparatus composed of three main components; namely an electronic control unit, a solenoid valve block and a pump motor. A magnetic coil of each solenoid valve of a valve block is encased in a molded resin that encloses electric conductors leading to and from each magnetic coil and terminates as an electric socket that is a push-fit into a casing housing said electronic control unit, said casing being of an unspecified material. The pump motor is illustrated as comprising a housing of molded resin, there being an extension of said housing that encloses electric conductors for the motor and acts as a socket that is a push-fit into said casing for housing the electric control unit. The casing has a circuit board therein having upstanding electrically conductive pins onto which said sockets can be pushed to electrically couple said solenoid valves and said pump motor to electric components on the circuit board in said casing. SUMMARY OF THE INVENTION The invention is as defined in the accompanying claims, the independent claims of which have been divided into a two-part form based on the assumption that DE-A-4 432 165 is the nearest state of the art. The object of the present invention is to provide a hydraulic control apparatus having a structure whereby the step of subassembling the coil and steel jacket shown in the prior art of Fig. 13 is eliminated, and whereby a waterproof structure at the connection surface between the hydraulic control unit and electronic control unit is not needed. A first means is a structure as described below. Specifically, a hydraulic circuit part of the solenoid valves is formed on a hydraulic control unit side, and a solenoid valve coils are formed on an electronic control unit side. The coils are integrally molded at the same time the resin case of the electronic control unit side is formed, and the moving part of the solenoid valve on the hydraulic control unit side is inserted to the through hole in the middle of the coil to form part of the closed magnetic circuit of the solenoid valve. In addition, a magnetic member is attached from an opposite side of the hydraulic unit with the electronic control unit disposed therebetween, and said magnetic member contacts a solenoid valve part inserted to the through hole in the middle of the coil, and goes around from the outside of the electronic control unit to form the magnetic circuit of the hydraulic control unit. A second means is a structure as described below. A moving part of each solenoid valve is formed on the hydraulic control unit side, and a coil of each solenoid valve is formed on the electronic control unit side. The coil is integrally molded simultaneously to forming -the resin case of the electronic control unit side, and the moving part of the solenoid valve on the hydraulic control unit side is inserted to the through hole in the middle of the coil to form part of the closed magnetic circuit of the solenoid valve as in the first means above. However, in this second means a magnetic plate forming part of the magnetic circuit of the solenoid valve and the coil mounted on the magnetic plate are formed integrally with the resin case of the electronic control unit, a circuit board housing space is formed in the resin case on the side opposite the coil, and the magnetic plate is exposed where resin is not molded on part of said magnetic plate extending outside the circuit board housing space. In both the first and second means above, if the mold blocks so that resin is not injected to the ends of the vehicle harness connector terminals and the coil board connecting pins projecting into the circuit board housing space inside the resin case when molding the resin case, interference with electrical connections to the electronic components can be avoided. Furthermore, a coil subassembly process can be eliminated by forming the resin molding around the coil winding of each solenoid valve in the same injection molding process when molding the resin case. In addition, a strong, waterproof structure can be achieved by molding the entire circuit board housing space on the inside of the resin case, including the magnetic plate, from resin. The ability to fasten the hydraulic control unit to the electronic control unit can also be provided by opening a bolt hole in the magnetic member and the part of the magnetic plate extending outside the circuit board housing space. Furthermore, in a hydraulic control apparatus having a moving part of a solenoid valve formed on the hydraulic control unit side, and a coil of the solenoid valve formed on the electronic control unit side, as a means for integrally comprising a hydraulic control unit containing a solenoid valve and an electronic control unit for controlling said hydraulic control unit, a first and a second magnetic plate forming common parts of a magnetic circuit for a plurality of solenoid valves are disposed on the hydraulic control unit side end and the opposite end of the coil, and the first and second magnetic plate are connected to the hydraulic control unit (fastened, for example, with a bolt) with a magnetic member disposed between the first and second magnetic plates. The magnetic material on the outside of each coil can be eliminated in this case because the part of the magnetic circuit outside the coil is formed from the first and second magnetic plates and the magnetic material disposed therebetween. Furthermore, in a hydraulic control apparatus comprising a plurality of coils, the direction of current flow through adjacent coils is mutually opposite such that the direction of current flow in approximately half the coils is opposite the direction of current flow in the remaining half of the coils. As a result, the magnetic fields generated by each of the coils are mutually cancelling. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiment thereof and the accompanying drawings throughout which like parts are designated by like reference numerals, and in which: Fig. 1 is a structural diagram of a first embodiment of the present invention; Fig. 2 is an assembly diagram showing the relationship between the electronic control unit and magnetic parts of the first embodiment of the present invention; Fig. 3 shows a first stage in the production of the electronic control unit of the first embodiment of the present invention; Fig. 4 shows a second stage in the production of the electronic control unit of the first embodiment of the present invention; Fig. 5 is a partial structural diagram of a first embodiment of the present invention when a normally open solenoid valve is disposed on the hydraulic control unit side; Fig. 6 is a structural diagram of a second embodiment of the present invention; Fig. 7.shows a first stage in the production of the electronic control unit of the second embodiment of the present invention; Fig. 8 shows a second stage in the production of the electronic control unit of the second embodiment of the present invention; Fig. 9 is a partial structural diagram of a second embodiment of the present invention when a normally open solenoid valve is disposed on the hydraulic control unit side; Fig. 10 is a partial structural diagram of a second embodiment of the present invention when a bolt seat is disposed in the middle of a magnetic plate of the second embodiment of the present invention; Fig. 11 is a structural diagram of a third embodiment of the present invention; Fig. 12 shows the electric current around the coils by the normally open solenoid valves and normally closed solenoid valves in the third embodiment of the present invention; and Fig. 13 is a cross sectional diagram showing the connections around a solenoid valve according to the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS To integrally connect a hydraulic control unit having a solenoid valve with an electronic control unit for controlling said hydraulic control unit, a moving part of a solenoid valve is formed on the hydraulic control unit side, and the coil of the solenoid valve is formed on the electronic control unit side. The resin case of the electronic control unit is formed by injection molding a resin, and the coil is also integrally molded at the time of injection molding. In addition, the member for connecting both units is also a magnetic circuit member, and is provided integrally or separately on the electronic control unit side as a means of eliminating an airtight means on the connecting surfaces of both units and an airtight means around the circuit board housing space of the electronic control unit containing the coil, and thus also eliminating the assembly steps therefor. Embodiment A preferred embodiment of the present invention thus comprised is described in detail below with reference to the accompanying figures. Fig. 1 is a structural diagram of a first embodiment of the present invention. As shown in Fig. 1 an electronic control unit 2 comprises a circuit board 9 on which electronic component groups 19 and 19' are mounted, a coil 4, connector terminal groups 11 and 11' for connection to a vehicle harness, a resin case 5, and a cover 20. A hydraulic control unit 1 constitutes part of a solenoid valve 3, which does not contain the coil 4 and comprises a housing 14 made from a magnetic material, a stationary core 13, a ring 15 made from a non-magnetic material, a moving core 17 with a valve body, a valve seat 18 fixed to the housing 14, and a spring 16. Note that one each of the preceding components is shown in Fig. 1. A magnetic member 6 shown in Fig. 1 and Fig. 2 is fastened to the hydraulic control unit 1 by means of a bolt 21. A manufacturing process used to produce the present invention as described above is described briefly more specifically below. As shown in Fig. 1, the hydraulic control unit 1 is assembled with the stationary core 13 and ring 15, and the ring 15 and housing 14, are press fitted to a fluid tight seal so that the end of the stationary core 13 is at a height that is even with the inside surface of an L-shaped curve in the magnetic member 6. As a result, no further waterproof structure is necessary. The magnetic circuit for driving the solenoid valve of this hydraulic control apparatus comprises the moving core 17, stationary core 13, magnetic member 6, and housing 14, and is closed around the inside and outside circumferences of the coil 4. As can be seen from Fig. 1 the hight of the L-shaped magnetic member 6 is such that when the magnetic member is secured to the hydraulic control unit 1 the lower arm of the magnetic member leaves no gap between the magnetic member 6 and the stationary core 13 of the solenoid valve. The performance of the solenoid valve is thus not impaired. Positioning precision error when a plurality of solenoid valves is provided can be absorbed by providing a gap 26 on the inside circumference of the coil. Providing such a gap also results in substantially no impairment of the performance of the coil as an electromagnet. The method of molding the resin case 5 is described next in further detail below. Shown in Fig. 3 is a bottom mold 50. A pin 10 for connecting the coil 4, and vehicle harness connector terminal groups 11 and 11', are inserted to the bottom mold 50, and the mold is then closed with a top mold 51 as shown in Fig. 4. It should be noted that the "top" and "bottom" references above are used solely for the convenience of referring to the orientation [of the hydraulic control apparatus] shown in Fig. 1, and do not specify any particular top and bottom arrangement of the molds during molding. A circuit board 9 is then mounted to the case assembly thus completed as shown in Fig. 1, and the electronic component groups 19 and 19', connecting pin 10 for the coil 4, and vehicle harness connector terminal groups 11 and 11' are electrically connected. The connecting pin 10 and connector terminal groups 11 and 11' are constrained by the mold and positioned by integral molding, and can be easily passed through the connector holes of the circuit board 9. While the cover 20 is attached after this, a completely waterproof enclosure can be easily formed inside the resin case 5 at this time by welding the cover 20 or using a similar method. After the circuit board 9 is mounted in the resin case 5, the electronic component groups 19 and 19' of the circuit board 9 are electrically connected to the connecting pin 10 projecting from the coil 4 into the circuit board housing space 29 and to the connector terminal groups 11 and 11'. At this point there are no electrical circuit parts exposed at the connection surface to the hydraulic control unit 1, and no further waterproof structure for this surface is therefore needed. The electronic control unit 2 is then fit to the magnetic member 6, and fastened to the hydraulic control unit 1 by a bolt 21. Note that it is not necessary to insertion mold a metal collar or similar separate member to bear the axial force of the bolt 21 because the face against which the bolt 21 pulls is the high hardness magnetic member 6 rather than a low hardness member such as the resin case 5. Conventionally when a plurality of coils is disposed, an insulation layer is provided around the coil, and the insulation layer is then clad with a magnetic material (this is to what the steel jacket 121 described in the prior art above corresponds). These elements have conventionally also limited the pitch between the plural coils. With the magnetic circuit construction of the present invention, however, the plural coils 4 can be disposed almost at the outside diameter of the coil layer, and the [overall unit] size can therefore be reduced. In addition, the molding surrounding the plurality of coils 4 can also be integrally formed, thereby strengthening the overall structure when compared with individually molding each of the coils 4. When it is difficult to use the same material for the resin case and the molding protecting the outside of the coil winding, it is possible to use a subassembly first prepared with a resin molding for protecting the outside of the coil winding. It should be further noted that while the invention has been described with reference to a normally closed solenoid valve, a normally open solenoid valve can be used as shown in Fig. 5. In Fig. 5 the stationary core 22 is on top, the moving core 23 is on the bottom, and the moving core 23 is enclosed in a tube 24 of a non-magnetic material. A yoke 25 for a magnetic circuit is preferably press fit around the tube 24. Fig. 6 is a structural diagram of a second embodiment of the present invention. Note that like parts are referenced with like numbers in the first embodiment described above and in the second embodiment shown in Fig. 6. As shown in Fig. 6 an electronic control unit 2 comprises a circuit board 9 on which electronic component groups 19 and 19' are mounted, a coil 4, magnetic plate -28, connector terminal groups 11 and 11' for.connection to a vehicle harness, a resin case 5, and a cover 20. A hydraulic control unit 1 constitutes part of a solenoid valve 3, which does not contain the coil 4 and comprises a housing 14 made from a magnetic material, a stationary core 13, a ring 15 made from a non-magnetic material, a moving core 17 with a valve body, a valve seat 18 fixed to the housing 14, and a spring 16. Note that one each of the preceding components is shown in Fig. 6. The electronic control unit 2 is fastened to the hydraulic control unit 1 by means of a bolt 21. A manufacturing process used to produce the structure described above is described briefly in detail below. The hydraulic control unit 1 is assembled with the stationary core 13 and ring 15, and the ring 15 and housing 14, press fit to a fluid tight seal so that the end of the stationary core 13 is flush with the end of the housing 14. As a result, no further waterproof structure is necessary. The magnetic circuit for driving the solenoid valve of this hydraulic control apparatus comprises the moving core 17, stationary core 13, magnetic plate 28, and housing 14, and is closed around the inside and outside circumferences of the coil 4. The gap between the magnetic plate 28 and the housing 14, and between the magnetic plate 28 and the stationary core 13, can be ignored because the end of the stationary core 13 on the hydraulic control unit 1 side is flush with the end of the housing 14. The performance of the solenoid valve is thus not impaired. While only one solenoid valve and one bolt 21 are described above, it will be obvious that a plurality of these can be provided as necessary. Positioning precision error when a plurality of solenoid valves is provided can be absorbed by providing a gap 26 on the inside and outside circumferences of the coil. Providing such a gap also results in substantially no impairment of the performance of the coil as an electromagnet. The method of molding the resin case 5 is described next in further detail below. Shown in Fig. 7 is a bottom mold 60. A magnetic plate 28 is placed on the bottom mold 60, and vehicle harness connector terminal groups 11 and 11', are inserted. It should be noted that the "bottom mold" reference above is used solely for the convenience of referring to the orientation of the hydraulic control apparatus shown in Fig. 6, and does not specify any particular top or bottom arrangement of the mold during molding. The coil 4 is then set in position. The coil 4 is substantially positioned by inserting the connecting pin 10 of the coil 4 to the bottom mold 60, and is then accurately positioned by fitting into the recess 7 in the top of the magnetic plate 28. The mold is then closed as shown in Fig. 8. The magnetic plate 28 is constrained at the bottom mold 60 by the outside circumference part, and at the top mold 61 by the entire inside surface of the coil 4 and by part of the outside of the coil 4, and is thus firmly secured inside the mold. The coil 4 is constrained by the top mold 61 on the inside and outside circumference and top sides, and by the magnetic plate 28 on the bottom. Because the coil 4 is accurately positioned to the magnetic plate 28 before the mold is closed, the coil 4 will not be crushed by the top mold 61 when the mold is closed. The connector terminal groups 11 and 11' are also constrained by the bottom mold 60 and top mold 61. The resin case 5 is next injection molded as shown in Fig. 6. A resin molding for protecting the outside of the coil 4 is also formed at this time, and a hood 27 for a vehicle connector is also formed. As a result, the vehicle harness connector terminal groups 11 and 11' and the connecting pin 10 projecting from the coil 4 into the circuit board housing space 29 are accurately positioned by the bottom mold 60 with the waterproof structure inside the resin case 5 retained. After the circuit board 9 is mounted to the resin case 5, it is electrically connected to the connecting pin 10 and to the connector terminal groups 11 and 11'. If the resin case 5 and cover 20 are sealed by welding or other method, a completely waterproof structure can be achieved inside the resin case 5. At this point there are no electrical circuit parts exposed at the connection surface to the hydraulic control unit 1, and no further waterproof structure for this surface is therefore needed. If the connecting pin 10 of the coil 4 reaches the circuit board housing space 29 by passing through a hole 8 provided in the magnetic plate 28, and the connecting pin 10 is completely covered with resin other than at the part exposed to the circuit board housing space 29, no further waterproof structure or insulation structure is needed for the winding or the overall coil 4. The gate supplying resin is disposed below the magnetic plate 28 in order to mold the resin case 5 first, and then supply resin to the outside of the coil 4. As a result, part of the top of the magnetic plate 28 is preferably formed as a resin channel 12. The magnetic plate 28 is also constrained by the top mold 61. As a result, the part not covered by resin during molding can be used in a magnetic circuit. The circuit board 9 is then mounted to the thus completed case subassembly, and the electronic component groups 19 and 19', connecting pin 10 of the coil 4, and vehicle harness connector terminal groups 11 and 11' are electrically connected. Because the connecting pin 10 and vehicle harness connector terminal groups 11 and 11' are constrained by the mold and positioned by integral molding, they can be passed easily through the connecting holes in the circuit board 9. While the cover 20 is installed after this, a completely watertight enclosure can be easily formed inside the resin case 5 at this time by welding the cover 20 or using a similar method. The last step is to fasten the electronic control unit 2 to the hydraulic control unit 1 with a bolt 21. The part of the magnetic plate 28 constrained by the bottom mold 60 and top mold 61 at top and bottom is preferably used as the bolt seat. In this manner the surface contacting the bolt 21 is the high hardness magnetic plate 28 rather than a low hardness member such as the resin case 5, and it is therefore not necessary to insertion mold a metal collar or similar separate member to bear the axial force of the bolt 21. Conventionally when a plurality of coils is disposed, an insulation layer is provided around the coil and the insulation layer is then clad with a magnetic material (this is to what the steel jacket 121 described in the prior art above corresponds). These elements have conventionally also limited the pitch between the plural coils. With the magnetic circuit construction of the present invention, however, plural coils 4 can be disposed almost at the outside diameter of the coil layer, and the [overall unit] size can therefore be reduced. In addition, the molding surrounding the plurality of coils 4 can be integrally formed, thereby strengthening the overall structure when compared with individually molding each of the coils 4. It should be noted that while the above embodiment has been described using a housing 14 made from a magnetic material as part of a magnetic circuit, the housing itself does not need to be of a magnetic material, and one or a plurality of members of a magnetic material can be provided passing from the magnetic plate 28 through the coil 4 to moving core 17 to close a magnetic circuit. When it is difficult to use the same material for the resin case and the molding protecting the outside of the coil winding, it is possible to use a subassembly first prepared with a resin molding for protecting the outside of the coil winding. Furthermore, when securely holding the magnetic plate 28 inside the mold is more important than a waterproof structure, the back of the coil member can be supported by the mold. It should be further noted that while the invention has been described with reference to a normally closed solenoid valve, a normally open solenoid valve can be used as shown in Fig. 9. Note, further, that the structure of the normally open solenoid valve shown in Fig. 9 is identical to that shown in Fig. 5. Furthermore, while the bolt 21 has been described as being disposed near the outside circumference, it can also be disposed in the middle as shown in Fig. 10. In this case a hole is opened in the circuit board 9, a wall surface 30 containing the bolt hole is provided in the resin case 5, and the wall surface 30 is also welded to the cover 20 when the cover 20 is welded in place. As a result, a bolt 21 can be provided in the middle without departing from the scope of the present invention. Fig. 11 shows a third embodiment of the present invention. While the housing of the hydraulic control unit, and more specifically the part housing the components of the solenoid valve, can be made from a magnetic material, a non-magnetic light metal is commonly used to reduce the weight. The third embodiment of the present invention specifies the structure of a hydraulic control unit suitable for use in combination with the electronic control unit of the second embodiment when the housing is a non-magnetic material. The housing 71 of the hydraulic control unit 1 is made from a non-magnetic material. One normally-closed solenoid valve 3 not containing a coil 4 comprises a yoke 72 made from a magnetic material, a second magnetic plate 73 made from a magnetic material, a stationary core 13, a ring 15, a moving core 17 with a valve body, a valve seat 18 fixed to the yoke 72, and a spring 16; note that one each of these components is shown in Fig. 11. One normally-open solenoid valve 80 likewise not containing a coil 81 comprises a yoke 82 made from a magnetic material, a second magnetic plate 73 made from a magnetic material, a stationary core 83, a ring 84 made from a non-magnetic material, a moving core 85 with a valve body, a valve seat 86 fixed to the moving core 83, and a spring 87; note that one each of these components is shown in Fig. 11. The electronic control unit 2 and hydraulic control unit 1 are fastened together by a bolt 21 with a collar 74 made from a magnetic material. The magnetic circuit of a normally closed solenoid valve of this hydraulic control apparatus comprises the moving core 17, stationary core 13, magnetic plate 28, collar 74, second magnetic plate 73, and yoke 72. To distinguish it from the second magnetic plate 73, magnetic plate 28 is referred to hereafter below as a first magnetic plate 28. The magnetic circuit of a normally open solenoid valve comprises a stationary core 83, moving core 85, yoke 82, first magnetic plate 28, collar 74, and second magnetic plate 73. By thus using the first magnetic plate 28, collar 74, and second magnetic plate 73, i.e., common parts that are each separated from the solenoid valve, to form part of the magnetic circuits, it is not necessary to dispose these magnetic materials around each of the coils 4 when a plurality of solenoid valves is provided. Even more particularly, if structured so that the current flows in opposite directions through adjacent coils, the size of the magnetic circuit part formed by these common parts can be reduced. This is described below using by way of example an antilock brake system for a four wheel vehicle in which a total of eight solenoid valves, including one normally closed solenoid valve and one normally open solenoid valve for each wheel, is used for the control valves. This type of antilock brake system is known to operate in three modes: a pressurize mode in which- no current flows to either solenoid valve; a hold mode in which current flows only to the normally open solenoid valve; and a depressurize mode in which current flows to both solenoid valves. In other words, when current flows to a normally closed solenoid valve, current also always flows to the corresponding normally open solenoid valve. As shown in Fig. 12, if the current flow through the coils of the normally open solenoid valves is the same in, for example, the right front and right rear wheels, then current flows in the opposite direction through the coils of the left front and left rear wheels. In addition, the current flow in the coil of a normally closed solenoid valves is opposite that of the corresponding normally open solenoid valve. As a result, if [the brake pressure for] both right wheels is held simultaneously, i.e., if current flows to the normally open solenoid valves for both right wheels, the fields generated by both valves have the same alignment, and the magnetic circuit part formed by the above common parts must have a magnetic circuit area sufficient for two coils. However, if current is supplied to the normally open solenoid valves for all four wheels, the fields generated by the valves will cancel each other out outside the coil, and a magnetic field will not be produced in the magnetic circuit part formed by the common parts, particularly in collar 74. Moreover, when current is supplied to a normally closed solenoid valves, current is also always supplied to the corresponding normally open solenoid valve. As a result, the field generated by the normally closed solenoid valve around the coil is always cancelled by the field generated by the normally open solenoid valve. The magnetic circuit area of the magnetic circuit part formed by the above common parts must therefore only be large enough for two coils, and when compared with an apparatus in which a steel jacket is used around each solenoid valve, can be reduced to 1/4. To avoid magnetic saturation of the first magnetic plate 28 and second magnetic plate 73, the coil current preferably flows in opposite directions in adjacent coils with an approximately equal distribution of current flow in both directions. It should be noted that while the third embodiment above has been described in combination with the second embodiment, it can also be easily achieved in combination with the first embodiment. In a hydraulic control apparatus according to a first embodiment of the present invention, a coil of a solenoid valve is integrally molded with a resin case of an electronic control unit, and solenoid valve parts disposed to a hydraulic control unit are inserted to a through hole in the middle of the coil; magnetic members with .the electronic control unit disposed therebetween are attached, and a coil forming part of the magnetic circuit of the solenoid valve is integrally molded with the resin case of the electronic control unit. As a result, a separate subassembly process is not needed as a result of the solenoid valve construction. A water resistant structure in which the area around the coil connecting pin is covered with resin in this integrated molding process can also be easily achieved. This can improve reliability in addition to yielding cost benefits. If the outside of the winding is also molded at this time, another step in the coil production process can be eliminated, thus yielding further cost benefits. Because a resin molded construction is used for the entire circuit board housing space in particular, the reliability of the waterproof structure of the circuit board housing space is high. In a hydraulic control apparatus according to a second embodiment of the present invention, the coil is placed on a magnetic plate and integrally molded at the same time the resin case of the electronic control unit is molded. As a result, a separate subassembly process is not needed as a result of the solenoid valve construction, a water resistant structure in which the area around the coil connecting pin is covered with resin in this integrated molding process can be achieved, the outside of the winding can also be molded at this time, and reliability can thus be improved and cost reduced as in the first embodiment above. Furthermore, resin is not injected where the magnetic plate is held when the magnetic plate is integrally molded, and this part can be actively used in a magnetic circuit. The part of the magnetic plate extending outside the circuit board housing space is outside the waterproof structure, and can be used for placing bolt holes for attachment. In particular, because a resin molded structure is used throughout the circuit board housing space, slight separation between the resin and magnetic plate as a result of, for example, thermal hysteresis, there is absolutely no effect on the waterproof structure, and a high reliability circuit board housing space can be achieved. Furthermore, a plurality of coils 4 can be arranged at almost the outside diameter of the winding, thereby reducing size. A surrounding molding for a plurality of coils 4 can also be integrally molded, thereby strengthening the overall structure when compared with individually molding each of the coils 4. Moreover, common magnetic circuit parts can also be used as connecting members of the hydraulic control unit and electronic control unit, and by further reversing the direction of current flowing to adjacent coils with an approximately equal distribution of current flow in both directions, the fields generated by each of the coils can be mutually cancelling. As a result, the common magnetic circuit parts can be made smaller, and the size and cost of the apparatus can be reduced.

Claims: A hydraulic control apparatus including a hydraulic control unit (1) containing a solenoid valve (3) and an electronic control unit (2) for controlling said hydraulic control unit (1); a hydraulic circuit part of the solenoid valve (3) formed on the hydraulic control unit side, and a coil (4) of the solenoid valve formed on the electronic control unit side, wherein said coil (4) is encased in a molded resin; a case (5) housing a circuit board (9) therein on the electronic control unit (2) side, and wherein a moving core (17) of the solenoid valve (3) is in a through hole in the middle of the coil (4), and forms part of a closed magnetic circuit through the solenoid valve; characterized in that (A) said case (5) is of molded resin; (B) the resin in which the coil (4) of the solenoid is encased is integral with the resin of said case (5); (C) a magnetic member (6) is fastened to the base of the hydraulic control unit (1); and (D) the arrangement is such that the magnetic member (6) forms a closed magnetic circuit, in co-operation with the solenoid valve (3) and the hydraulic control unit (1). The hydraulic control apparatus according to claim 1 wherein the magnetic member (6) is attached from an opposite side of the hydraulic unit (1) with the electronic control unit (2) disposed therebetween, said magnetic member (6) contacts said hydraulic circuit part (13) of the solenoid valve inserted to the through hole in the middle of the coil (4), and goes around from the outside of the electronic control unit (2) to form a magnetic circuit of the hydraulic control unit (1). The hydraulic control apparatus according to claim 2 wherein an attaching part (21) is provided on the magnetic member (6) for fastening to the hydraulic control unit (1). A hydraulic control apparatus including a hydraulic control unit (1) containing a solenoid valve (3) and an electronic control unit (2) for controlling said hydraulic control unit (1); a hydraulic circuit part of the solenoid valve (3) formed on the hydraulic control unit side, and a coil (4) of the solenoid valve formed on the electronic control unit side, wherein said coil (4) is encased in a molded resin; a case (5) housing a circuit board (9) therein on the electronic control unit (2) side, and wherein a moving core (17) of the solenoid valve (3) is in a through hole in the middle of the coil (4), and forms part of a closed magnetic circuit through the solenoid valve; characterized in that (A) said case (5) is of molded resin; (B) the resin in which the coil (4) of the solenoid is encased is integral with the resin of said case (5); (C) a magnetic member (28) is fastened to the base of the hydraulic control unit (1); and (D) the arrangement is such that the magnetic member 28 forms a closed magnetic circuit, in co-operation with the solenoid valve (3) and the hydraulic unit (1); (E) wherein said magnetic member is a plate (28) that is integral with the resin case (5) of the electronic control unit (2); and (F) the magnetic plate (28) extends beyond an end of said case (5) such that it has an exposed part. The hydraulic control apparatus according to claim 4 wherein an attaching part (21) for fastening to the hydraulic control unit (1) is formed on said exposed part of the magnetic plate (28) extending beyond case (5) providing the circuit board housing space. The hydraulic control apparatus according to claim 4 or claim 5 wherein, except for end parts of vehicle harness connector terminals (11 and 11 1 ) and circuit board connecting pins (10) projecting into the circuit board housing space inside the resin case (5), all parts of the conductive terminals of the solenoid valve coil (4) are coated with resin. A hydraulic control apparatus including a hydraulic control unit (1); said hydraulic control unit (1) comprising a housing (71), said housing containing a plurality of solenoid valves (3, 80); an electronic control unit (2) for controlling said hydraulic control unit (1); coils (4, 81) formed on the electronic control unit (2), one for each solenoid valve (3, 80); said coils being encased in a molded resin; a case (5) housing a circuit board (9) therein and forming part of the electronic control unit (2); characterized in that : (A) said case (5) is of molded resin; (B) the resin in which the coils (4, 81) of the solenoids are encased is integral with the resin of said case (5); (C) a magnetic member (73) is'fastened to the base of the hydraulic control unit (1); (D) said magnetic member (73) being a plate; there being a further plate (28) of magnetic material spaced from the magnetic member (73) that is fastened to the base of the hydraulic control unit; the two plates being connected to each other via magnetic spacing members (74) disposed between said two plates; and the resin impregnated coils (4, 81) are positioned between said two plates; the two plates (28, 73), the solenoid valves (3, 80), and the magnetic spacing members (74) forming closed magnetic circuits; and in that : (E) the housing (71) of the hydraulic control unit (1) is of non magnetic material. The hydraulic control apparatus according to claim 7 wherein the hydraulic control apparatus comprises a plurality of coils (4, 81) such that the direction of current flow through adjacent coils is mutually opposite.

Inventors: HASHIDA KOICHI, HASHIDA, KOICHI
Applicants: SUMITOMO ELECTRIC INDUSTRIES, SUMITOMO ELECTRIC INDUSTRIES, LTD.
Application year: 1997
Main classification: B60T8
IPC codes: F16K31, B60T8