MXPA06006715A - Solenoid valve with fitted shoulder - Google Patents

Abstract

Solenoid valve for controlling the flow of a fluid in a hydraulic circuit, comprising a valve body having at least one fluid duct, a stopper for allowing or preventing the flow of fluid in the fluid duct, a mechanical connection to actuate the stopper, an electromagnetic actuator arranged to actuate the mechanical connection, and a coupling between the electromagnetic actuator and the valve body via a jacket surrounding the electromagnetic actuator and engaged on a shoulder of the valve body. The jacket holds the electromagnetic actuator in axial engagement against the valve body in a direction of engagement. The shoulder comprises two matching half-washers engaged radially in a peripheral groove of the valve body.

Description

SOLENOID VALVE WITH ADJUSTED SUPPORT TECHNICAL FIELD The present invention is concerned with solenoid valves for controlling the flow of a fluid in a hydraulic circuit, such as the solenoid valves used to control the flow of liquid to cool and lubricate pistons in the engines of Motor vehicles. Generally, and as described for example in JP 2000-136888 A, US 2004/0113112 Al or US 4,578,662 A, solenoid valves for controlling the flow of a fluid in a hydraulic circuit comprise: valve having at least one fluid conduit, a plug for allowing or preventing the flow of fluid in the fluid conduit and a mechanical connection for actuating the cap, an electromagnetic actuator arranged to drive the mechanical connection, a coupling between the actuator electromagnetic and the electromagnetic body and the valve body, via a jacket surrounding the electromagnetic actuator and coupled with a shoulder projecting from the valve body, which holds the electromagnetic actuator in axial engagement against the valve body in a coupling direction. The valve body is generally cylindrical, in order to be coupled and sealed in a housing provided in a hydraulic block in which the fluid to be controlled circulates, usually, the electromagnetic actuator protrudes from the hydraulic block and is retained by its coupling to the valve body. Coupling via a jacket coupled on the shoulder projecting from the valve body makes it possible to attach a magnetic actuator of sufficient power whose outer diameter is therefore greater than that of the valve body. This mode of coupling between the valve body and the electromagnetic actuator, via a prominent shoulder, is costly to produce just as much as in the material used as in labor and machine time. To produce a prominent protrusion on the valve body, this is usually an asymmetric part, it is necessary to start with the part having an external diameter equal to or slightly larger than the outer diameter of the shoulder and to machine this part in practically its entire length with the in order to substantially reduce its external diameter. This operation can be carried out in particular by means of a lathe. Thus, a single-block valve body preform is obtained by removing a large amount of material, the shoulder usually being present only over a very short length of the final valve body.

In order for the valve body to have geometric - and dimensional quality and sufficient to ensure its sealed coupling in a hydraulic block, precision grinding is necessary over its entire length. Due to the presence of prominent protrusion, it is necessary to make use of precision sinking-cutting rectification. The sinking-cutting precision rectification is carried out by means of a forward radial movement of the mill, a radial forward movement that differs depending on whether the mill finishes grinding accurately or the mill finishes accurately grinding the part of the mill. valve body whose diameter has been previously reduced during rough machining. Then multiple steps are necessary due to the limited width of the precision mill which is usually less than the length of the valve body preform. This method of precision sinking-cutting rectification is therefore costly in machining time, labor and in inspections. Consequently, the production of a valve body with protruding shoulder has hitherto been costly both during rough machining and during precision grinding in order to obtain a valve body which satisfies the geometric and dimensional quality conditions. However, this geometric and dimensional quality is still necessary for the same operation of the valve body in the solenoid valve, to ensure good circulation of the fluid in the hydraulic circuit, without leaks or defects in the control of its flow. Furthermore, from DE 38 14 156 Al and its US equivalent 4,979,542 A, there is known a solenoid valve (Figure 2) in which the actuator is coupled to the valve body via a jacketed coupling on a shoulder consisting of itself an asymmetric part fitted to the valve body and attached via a material reduction. This omits the sinking-cutting precision rectification stages, thanks to the absence of a prominent monoblock protrusion on the valve body. However, it is necessary to provide the additional reduction and costly operation of material in order to attach the asymmetric part fitted to the valve body. In addition, the mechanical strength of the reduction of material is not guaranteed and the result is a risk that the separation may progressively appear and the coupling may break. In addition, the asymmetrical piece equipped has a complex shape which increases the cost of manufacturing.

BRIEF DESCRIPTION OF THE INVENTION A first problem proposed by the invention is to design a solenoid valve structure that can be produced at less cost, reducing material waste, labor time and otherwise machine time. According to another aspect, the object of the invention is to produce such a solenoid valve in which the valve body remains compatible with the current geometrical and dimensional requirements and in which the driving force produced by the electromagnetic actuator remains compatible with the reliable drive requirements of the plug to control the fluid in all circumstances. Simultaneously, the invention also seeks to produce a shoulder on a valve body that is reliable and can easily withstand the mechanical stresses associated with the operation of the solenoid valve. To obtain these and other objectives, the invention proposes a solenoid valve for controlling the flow of a fluid in a hydraulic circuit comprising: a valve body, having at least one fluid conduit, at least one peripheral slit , a plug for allowing or preventing the flow of fluid in the fluid conduit and a mechanical connection for operating the plug, an electromagnetic actuator arranged to drive the mechanical connection, a coupling between the electromagnetic actuator and the valve body, via a jacketed surrounding the electromagnetic actuator and coupled with a shoulder equipped in the valve body, which keeps the electromagnetic actuator in axial engagement against the valve body, in a coupling direction, - the shoulder comprises a set of two half-washers of correspondence , radially coupled in the peripheral groove and radially retained in the peripheral groove through the jacket. With such a solenoid valve structure, it is then possible to obtain a cost saving cost saving substantially in manufacturing and assembly, by separately manufacturing the valve body itself and the corresponding retaining washers of smaller dimensions pieces without waste of greater material. Semi-washers form pieces whose simple form can be produced at low cost. Then, the valve body preform that has no protrusion can be precision ground at a lower cost using precision through feed rectification. During assembly, the jacket adaptation after the corresponding semi-washers are inserted into the peripheral groove simultaneously, in a single operation, joins the half-washers to the valve body and attaches the electromagnetic actuator to the valve body. Advantageously, the invention also makes possible the coupling of an electromagnetic actuator whose outer diameter can be manufactured substantially larger than the outer diameter of the valve body about the coupling direction. The valve body thus provided with its equipped shoulder can be used with an electromagnetic actuator of large dimensions, particularly in the case where a considerable driving force is necessary under the conditions of use of the solenoid valve thus formed. This implementation is also fast and the shoulder thus produced will be able to withstand very strong mechanical stresses during the operation of the solenoid valve. Advantageously, the valve body can have an external asymmetric cylindrical shape. Thus, the preform can be precision ground by a precision through-feed rectification process and no longer by a sinking-cutting precision rectification process. The feed-through precision grinding process is less expensive and simpler to implement than the sinking-cutting precision grinding process. According to one embodiment of the invention, the electromagnetic actuator may comprise: a winding of generally cylinder shape defining at its center a cylindrical housing between a first end and a second end along the coupling direction; - a box placed around the winding, which encloses the cylindrical housing of the winding at the first end and holds a ferromagnetic washer against the first end to form a first pole of the magnetic circuit, a magnetic core that can be moved in longitudinal translation in the housing cylindrical winding. The box can be made of plastic which makes it possible to substantially lighten the solenoid valve thus formed by reducing production costs. Preferably, the mechanical connection may comprise a rod that slides in an axial cylindrical bore of the valve body to drive the plug during movements of the movable magnetic core. Advantageously, the valve body may comprise an axial nose partially engaged in the cylindrical housing of the winding and forming a second pole of the magnetic circuit. Thus, the solenoid valve is easier to assemble, the axial nose provides easy centering of the valve body in relation to the winding of the electromagnetic actuator. In the case where the valve body consists of a ferromagnetic material, the latter thus effectively closes the magnetic circuit of the electromagnetic actuator to provide it with excellent operation. According to the invention, the axial nose can be a fixed ferromagnetic core fitted at the end of the valve body. In particular, this makes it possible to use, to form the valve body, a material more appropriate to the particular requirements of using the solenoid valve without, for that, compromising the correct operation of the latter. It will be possible, for example to produce the aluminum valve body for the purpose of reducing the weight of the solenoid valve. Advantageously, the fixed core can be retained on the electromagnetic actuator by at least one of a core retaining part, equipped and attached to the periphery of the fixed core and retained by the jacket. The assembly of the fixed core is therefore simple, safe and inexpensive since the production of a shoulder is not then necessary and the same advantages are derived from it as when the shoulder is produced on the valve body by means of a piece. equipped retention In this case, the core retaining part can be made of ferromagnetic material to magnetically connect the fixed core to the jacket, the valve body is made of non-magnetic material.

As an alternative, the valve body can be made of ferromagnetic material and at least one of the corresponding semi-washers is made of ferromagnetic material and the valve body is magnetically connected to the jacket.

BRIEF DESCRIPTION OF THE FIGURES Other objects, elements and advantages of the present invention will emerge from the following description of particular embodiments given with reference to the accompanying figures in which: - Figure 1 is a sectional view of a solenoid valve in accordance with one embodiment of the invention; and - Figure 2 is a perspective view showing the assembly of two corresponding semi-washers on a valve body, in the embodiment of Figure 1.

DESCRIPTION OF THE PREFERRED MODALITIES In the embodiment shown in Figures 1 and 2, a solenoid valve for controlling the flow of a fluid in a hydraulic circuit according to the invention comprises in particular a valve body 1 provided with a fluid conduit. axial la and two transverse fluid conduits Ib and le. The valve body 1 comprises a plug ld in the form of a ball to allow or prevent the flow of fluid in the fluid conduits la, Ib and le. The ball ld is held under pressure against a first seat by a spring lf. The ball ld can, however, be pushed away from the first seat against a second seat opposite to it. When the ball Id is pressed against the first seat, the latter prevents any communication between the transverse fluid conduit Ib and the transverse fluid conduit le. Then the fluid can circulate between the transverse conduit 1 and the axial conduit la. On the other hand, when the ball ld is pressing against the second seat lg, the latter locks the axial fluid conduit Ia and authorizes the fluid to circulate between the transverse fluid conduits Ib and via an axial cylindrical bore Ih in which a rod 2 is coupled with separation. This flow of fluid between the transverse fluid conduits Ib and it is made possible by the difference between the diameter DI of the axial cylindrical bore lh of the body 1 and the diameter D2 of the rod 2 which is coupled to slide in the axial cylindrical bore Ih in order to operate the ball ld. The solenoid valve also comprises an electromagnetic actuator 3, arranged to drive the rod 2 which itself forms a mechanical connection. A coupling is provided between the electromagnetic actuator 3 and the valve body 1. This coupling comprises a jacket 4 surrounding the electromagnetic actuator 3 and is coupled on a shoulder 50 fitted to the valve body 1. This jacket 4 thus retains the actuator electromagnetic 3 in axial engagement against the valve body 1 in a coupling direction II. According to the invention, the valve body 1 comprises a peripheral groove 12 at its end. The body retaining shoulder 50 comprises a set of two corresponding semi-washers 13a and 13b, radially coupled in the peripheral groove 12 as shown in Figure 2. The half-washers 13a and 13 are thus radially retained in the peripheral groove. 12 through the jacket 4, as illustrated in Figure 1. This implementation of the equipped body retaining shoulder 50 is simple, fast and inexpensive. In particular, it allows the production at a lower cost of a valve body 1 having an external asymmetric cylindrical shape. This specifically prevents many expensive machining operations and makes it possible to save a large amount of material. In addition, such a generally asymmetrical external cylindrical shape of the valve body 1 allows a precision through-feed rectification operation which is much less expensive than the precision sinking-cutting rectification that was used up to now. The external diameter D3 of the valve body 1 is specific to the use of the solenoid valve. The valve body 1 can for example be coupled in a bore of a motor block to control the flow of a fluid in a hydraulic circuit manufactured in the engine block. The perforation of the motor block therefore directly determines the external diameter D3 that must be given to the valve body 1. As for the electromagnetic actuator 3, the latter has an external diameter D4 which is a function of the force that needs to be applied to the ball ld to control the flow of fluid in the hydraulic circuit. This force therefore depends on the return force exerted by the spring lf and on the pressure of the fluid circulating in the conduits la, Ib and le. Thus, the driving force is specific to the use that is desired to be made of the solenoid valve and the external diameter D4 depends on it. It is emphasized that the external diameters D3 and D4 can consequently be very different. Thus, the shoulder 50 can have a height h that can be considerable and according to the invention this does not increase the manufacturing cost of the solenoid valve. By contrast, with the techniques used so far, the cost of producing a solid asymmetric cylindrical valve body is proportional to its height h. The electromagnetic actuator 3 comprises a winding 5 of generally cylindrical shape defining at its center a cylindrical housing 5a between a first end 5b and a second end 5c, along the coupling direction I-I. The electromagnetic actuator 3 also comprises a box 6 placed around the winding 5, which closes the cylindrical housing 5a of the winding 5 at the first end 5b. The housing 6 can be made of plastic and holds a ferromagnetic washer 14 against the first end 5b to form a first pole 14a of the magnetic circuit. The jacket 40 can advantageously be made of ferromagnetic material and thus form the main reinforcement part to conduct the magnetic field produced by the winding 5. The plastic case 6 has a thin thickness e which separates the ferromagnetic jacket 4 and the washer 14 from such that magnetic conduction is possible between these two elements. It is also possible to improve this magnetic conduction, that the washer 14 comprises peripheral teeth coupled in grooves made over the entire length of the plastic box 6, the teeth that come into contact without air space with cladding 4. A magnetic core 7 is mounted to be movable in longitudinal translation in the coupling direction II in the cylindrical housing 5a of the winding 5. The rod 2 is pressed axially against the movable magnetic core 7 and slides in a cylindrical axial bore lh of the valve body 1 under the pressure of the movable magnetic core 7 when the latter slides in the cylindrical housing 5a of the winding 5. This is how the ball ld is operated to prevent or allow the flow of fluid in the conduits la, Ib and le. In the embodiments of Figures 1 to 5, the movement of the movable magnetic core 7 in the cylindrical housing 5a of the winding 5 is limited by a fixed ferromagnetic core 8. This fixed core 8 is partially coupled in the cylindrical housing 5a of the winding 5 and forms a second pole 8a of the magnetic circuit. It is drilled with an axial bore 8b 'so that the rod 2 slides freely. This fixed core 8 is held on the electromagnetic actuator 3 by means of a retention piece of the core 9 fitted and attached on the periphery of the fixed core 8 and retained by the jacket 4. The retention piece of the core 9 can advantageously be made of ferromagnetic material , which magnetically connects the jacket 4 to the fixed core 8 which can also be made of ferromagnetic material. Thus a magnetic circuit is formed by the jacket 4, the retaining part of the core 9, the fixed core 8 and the washer 14. This magnetic circuit makes it possible to channel the magnetic field produced by the winding 5 to generate a driving force with the In order to move the movable magnetic core 7 in the cylindrical housing 5a. When the winding 5 is fed, the movable magnetic core 7 moves in the cylindrical housing 5a towards the fixed core 8 in the coupling direction II and thus causes the rod 2 to slide in the axial cylindrical bore Ih of the valve body 1 and in the axial bore 8b of the fixed core 8 for pushing the ball Id against the return force exerted by the spring If. The ball ld thus locks the second seat lg to prevent the circulation of fluid in the axial duct and then allow the fluid to flow in the transverse ducts Ib and, the fluid is apt to circulate in the axial cylindrical perforation lh • due to the diameter DI of the rod 2 which is smaller than the internal diameter of the axial cylindrical perforation Ih. When the winding 5 is no longer fed, the latter no longer exerts driving force on the movable magnetic core 7 and the spring If pushes the ball Id against the first seat le while causing the rod 2 to slide in the cylindrical bore axial Ih and the movable magnetic core 7 in the cylindrical housing 5a towards the first pole 14a in the coupling direction II. In the embodiment illustrated in Figure 1, the outer diameter D3 of the valve body 1 is larger than the diameter of the cylindrical housing 5a. In this case, the fixed core 8 has a smaller diameter, suitable for locking the cylindrical housing 5a at the second end 5c of the winding 5 while centering the valve body 1 on the electromagnetic actuator 3. The fixed core 8 is coupled at its other end in a corresponding axial housing li of the valve body 1. However, if the external diameter D3 were equal to the diameter of the cylindrical housing 5a of the winding 5, it could be contemplated that the valve body 1 itself comprises a axial nose partially engaged in the cylindrical housing 5a of the winding 5 and forming the second pole 8a of the magnetic circuit. In order to close the magnetic circuit, the valve body 1 and at least one of the corresponding semi-washers 13a, 13b to retain the body 1 would then be made of ferromagnetic material. The use of a fixed core 8 is thus useful, on the one hand, when the external diameter D3 of the body 1 is different from the diameter of the cylindrical housing 5a and on the other hand, when it is desired to produce a valve body 1 of a non-ferromagnetic material , of aluminum for example, in order to lighten the solenoid valve or because, in the context of use of the solenoid valve, a particular non-ferromagnetic material is required for the valve body 1.

In the particular embodiment shown in the figures, one of the corresponding semi-washers, in this instance, the semi-washers 13a, is extended radially to itself from an attachment ear 40a of the solenoid valve. The attachment ear 40a is for example pierced with a hole 40b for a clamping screw to pass therethrough. The attachment ear 40a is at the interface between the valve body 1 and the electromagnetic actuator 3 and can be pressed on the external face of a hydraulic block on which the valve body 1 is inserted. In the embodiment illustrated in the figures, the box 6 is made of low-cost lightweight material, for example plastic. However, it is possible to conceive, when necessary, that the box 6 be made of ferromagnetic material. Box 6 then participates to conduct the magnetic field in the magnetic circuit. This helps to obtain a greater driving force. The present invention is not limited to the modalities that have been explicitly described, but includes the various variants and generalizations thereof, contained in the field of the following claims.

Claims (11)

1. CLAIMS 1. A solenoid valve for controlling the flow of a fluid in a hydraulic circuit, characterized in that it comprises: - a valve body having at least one fluid conduit, at least one peripheral slit, a plug to allow or preventing the flow of fluid in the fluid conduit and a mechanical connection for actuating the plug, an electromagnetic actuator arranged to drive the mechanical connection, a coupling between the electromagnetic actuator and the valve body, via a jacket surrounding the electromagnetic actuator and coupled with a shoulder fitted to the valve body, which holds the electromagnetic actuator in axial engagement against the valve body in a coupling direction, characterized in that the shoulder comprises a set of two corresponding half-washers, radially engaged in the peripheral groove. and retained radially in the peripheral groove by the encam isado. The solenoid valve according to claim 1, characterized in that the end diameter of the electromagnetic actuator is markedly larger than the external diameter of the valve body about the coupling direction. 3. The solenoid valve according to claim 1 or claim 2, characterized in that the valve body has an external asymmetric cylindrical shape. The solenoid valve according to any of claims 1 to 3, characterized in that the electromagnetic drive comprises: - a winding in the general shape of a cylinder that defines at its center a cylindrical housing between a first end and a second end length of the coupling direction, - a box placed around the winding, which closes the cylindrical housing of the winding on the first end and holds a ferromagnetic washer against the first end to form a first pole of the magnetic circuit, a magnetic core that can be moved in longitudinal translation in the cylindrical housing of the winding. The solenoid valve according to claim 4, characterized in that the mechanical connection comprises a rod, which slides in an axial cylindrical bore of the valve body to actuate the plug during the movements of the movable magnetic core. The solenoid valve according to any of claims 4 or 5, characterized in that the valve body comprises an axial nose partially engaged in the cylindrical housing of the winding and forming a second pole of the magnetic circuit. The solenoid valve according to claim 6, characterized in that the axial nose is a fixed ferromagnetic core equipped at the end of the valve body. The solenoid valve according to claim 7, characterized in that the fixed core is held on the electromagnetic actuator by at least one core retention piece, equipped and attached to the periphery of the fixed core and retained by the jacket. The solenoid valve according to claim 8, characterized in that the at least one core retaining part is made of ferromagnetic material and magnetically connects the fixed core to the jacket, the valve body is made of non-magnetic material. The solenoid valve according to any of claims 4 or 5, characterized in that the valve body is made of ferromagnetic material and at least one of the corresponding semi-washers is made of ferromagnetic material and magnetically connects the body of valve to the jacket. The solenoid valve according to any of claims 1 to 10, characterized in that at least one of the corresponding semi-washers is radially extended to form an attachment ear of the solenoid valve.