Hydraulic pressure control valve

Abstract: In a mechanical component, a component body (50) includes an opening (54), a first bore (51) located at the opening and having a diameter of D₁, and a second bore (52) located on the opposite side of the first bore from the opening and having a diameter of D₂, where D₁ is larger than D₂. A step (53) is formed through which the first and second bores are connected to each other. An annular dish-shaped plate (60) is urged against the step of the component body until the dish-shaped plate is deformed into a planar-plate configuration, to bite an outer periphery of the dish-shaped plate to a periphery of the first bore. Thus, an annular element (60′) formed by the dish-shaped plate is fixedly mounted to the component body. If the above-mentioned support structure is applied to a valve spring of a hydraulic pressure control valve, it is possible to surely stabilize the support of the valve spring.

Description: The present invention relates to a hydraulic control valve for a brake system of an automotive vehicle or the like. Generally there are many structures in which an annular member or element is fixedly mounted to an opening of a component body, or another component to be incorporated in the component body has an end which is fixedly mounted to an inner periphery of the opening. The annular element at the opening serves as a spring retainer, a stopper or the like for preventing another component to be inserted in the component body from coming out of the latter, for example. Conventionally, as a technique in which an annular element or another internal component is fixedly mounted to the opening of the component body, a way is well known in which an annular groove is formed in the inner periphery of the opening, and the annular element such as a C-shaped ring or the like or an end of another internal component is fitted in the annular groove. For instance, EP Patent Publication no. 0 157 158 A2 or GB Patent Application No 2 195 408A disclose a hydraulic pressure control valve in which an annular groove is formed in an inner periphery of an opening in a valve body to be threadedly engaged with a portion of a brake master cylinder, which faces toward a hydraulic chamber of the brake master cylinder, and an end of a valve spring is fitted in the groove and is supported at the opening. With the conventional technique described above, first, considerable time is taken since another groove must be processed at the inner periphery of the opening and, moreover an annular element or another internal component must be fitted in the groove. Secondly, because the annular element or another internal component is fitted merely in the groove, the support of the annular element or another compartment is unsteady. For instance, the hydraulic pressure control valve disclosed in the aforesaid EP Patent Publication No. 0 157 158 A2 or GB Patent Application No. 2 195 408A will be considered with reference to the unsteadiness of the support of the annular element. Generally, the hydraulic pressure control valve is arranged at a portion of a tandem master cylinder, which communicates with a wheel cylinder for rear wheels. When failure occurs in a brake circuit for front wheels, a way is taken in which a control function of the control valve is released. At failure, a follower piston of the tandem master cylinder moves excessively or violently to incline a poppet valve element of the hydraulic pressure control valve, thereby releasing the pressure regulating function. Accordingly, since a biased or one-sided force is applied to a valve spring which urges the posset valve element, it is important to ensure the support of the valve spring. In this respect, it is impossible for the conventional technique to sufficiently respond to the necessity that is the stability or steadiness of the support of the valve spring. In accordance with the present invention a hydraulic pressure control valve for use with a master cylinder and a wheel cylinder comprising a valve body formed therein with a stepped bore; a piston inserted in said stepped bore for sliding movement therealong; an inlet chamber defined in said valve body on the side of one end of said piston and capable of communicating with said master cylinder; an outlet chamber defined in said valve body on the side of the other end of said piston and capable of communicating with said wheel cylinder; passage means formed in said piston, said inlet and outlet chambers communicating with each other through said passage means; a valve element arranged in facing relation to an end of said passage means which is located in facing relation to said inlet chamber; and valve spring means for biasing said valve element toward a predetermined position located at the end of said passage means, characterised in that said valve body includes, adjacent said inlet chamber, an opening, a first bore located at said opening and having a diameter of D₁, a second bore located on the opposite side of said first bore from said opening and having a diameter of D₂, where D₁ is larger than D₂, and a step through which said first and second bores are connected to each other; and that an annular element is fixedly mounted to said valve body in such a manner that an annular dish-shaped plate forming said annular element is urged against said step of said valve body until said dish-shaped plate is deformed into a planar-plate configuration, to bite an outer periphery of said dish-shaped plate to a periphery of said first bore, said annular element serving as a spring retainer for supporting an end of said valve spring means which is remote from the one end of said piston, the diameter of the central hole of said annular element being less than that of said second bore. The invention will now be described further by way of example with reference to the accompanying drawings in which :- Fig 1 is a longitudinal cross-sectional view of a hydraulic pressure control valve according to an embodiment of the invention; Figs 2(A) through 2(C) are fragmentary views showing a support structure for an annular element; Fig 3 is a front elevational view of a modification of a dish-shaped plate forming the annular element; and Fig 4 is a fragmentary view of another embodiment of the invention. Referring to Fig 1, there is shown a hydraulic pressure control valve, generally designated by the reference numeral 10. The valve 10 comprises a valve body 12 which is made of metal and which has a flange 12a intermediate its ends. One end of the valve body 12 is provided with male threads 12b for mounting to a discharge section of a master cylinder 81. The other end of the valve body 12 is formed with a pipe-mounting section or an outlet chamber 12c for connection to a wheel cylinder 82 of a brake device. An O-ring seal 14 located adjacent the right-hand end face of the flange 12a and about the outer periphery of the valve body 12 serves to maintain sealing between the master cylinder 81 and the valve body 12. The valve body 12 has a longitudinal bore 18. The end of the valve body 12 to be adjacent the master cylinder 81 includes an inlet chamber 32. The bore 18 extends to the other end of the valve body 12, where the outlet chamber 12c is located. The bore 18 is stepped, and a stepped piston 20 is inserted in the bore 18 for sliding movement therealong. The piston 20 has a smaller diameter portion 21 at its right end, as viewed, and, adjacent its other end, a larger diameter portion 22. The piston 20 further has a flange 23 between the smaller diameter and larger diameter portions 21 and 22. The piston 20 is provided with a through bore or a passage 24. The passage 24 is a communication passage connecting the inlet chamber 32 and the outlet chamber 12c. A pair of O-ring seals 26a and 26b at the respective larger diameter and smaller diameter portions 22 and 21 prescribe or regulate pressure receiving areas at the respective opposite ends of the piston 20. At the stage in which hydraulic pressure discharged from the master cylinder 81 is low, the piston 20 is loaded by spring 28, and the flange 23 of the piston 20 abuts against a step 12d of the valve body 12, so that the piston 20 is held stationary. The passage 24 extending centrally through the piston 20 has an opening at which a valve seat 30 is arranged. The valve seat 30 faces toward the inlet chamber 32 at the opening of the valve body 12 on the side of the one end thereof. A poppet valve element 40 made of plastic is accommodated in the inlet chamber 32. When the hydraulic pressure reaches a predetermined value, the force acting upon the difference between the larger-diameter and smaller-diameter portions 22 and 21 overcomes the biasing force of the preload spring 28, so that the piston 20 moves toward the inlet chamber 32. By this movement, the poppet valve element 40 is seated on the valve seat 30. Thus, the known hydraulic control is effected. The piston 20 is made of material such as, for example, plastic which has a certain elasticity or resiliency. Accordingly, when the piston 20 moves violently so as to be abutted against the metallic valve body 12, no abnormal or foreign sound occurs to cause anxiety. Thus, it is no longer necessary to form a restriction which reduces the area of the passage 24 for hydraulic fluid, in order to prevent the piston 20 from being returned violently. The poppet valve element 40 is a molded article made of plastic, and has a domed valve section 41 at a left-hand or lower end center and an annular rim 42 surrounding the valve section 41. The rim 42 and the domed section 41 are joined by a trunk section 43. A stem 44 has a smaller diameter than and is arranged adjacent the trunk section 43. The stem 44 considerably projects outwardly from the opening of the valve body 12. The stem 44 of the poppet valve element 40 engages a flange or the like of a piston within the master cylinder 81 when the piston within the master cylinder 81 moves violently due to some malfunction, to release the hydraulic pressure control action of the hydraulic pressure control valve 10. The poppet valve element 40 is urged against the valve seat 30 under biasing force of a valve spring 46. The valve body 12 is of one-piece structure without being divided into two, and a component body 50 is fixedly mounted to the valve body 12 in such a manner that the component body 50 is fitted in the inlet chamber 32 and an end face of the component body 50 is caulked to the one end of the valve body 12. The valve spring 46 has one end thereof which is supported by the poppet valve element 40. The other end of the valve spring 46 is supported by an annular or circular element 60' which is located at an opening 54 of the component body 50. The component body 50 is made of free cutting carbon steel (JIS: SUM 24L), while the annular element 60 is made of cold rolled carbon steel (JIS: SPCC). However, the dish-shaped plate 60 may be made of material identical with that of the component body 50. A structure for mounting or supporting the annular element 60' can be seen in Figs. 2(A) through 2(C). The component body 50 includes, in addition to the opening 54, a first bore 51 located at the opening 54 and having a diameter D₁, and a second bore 52 located on the opposite side of the first bore 51 from the opening 54 and having a diameter D₂, where D₁ is larger than D₂. The component body 50 is annular in shape and is provided at its one end with the opening 54. The opening 54 and the first and second bores 51 and 52 are in concentric relation to an outer periphery of the component body 50. The opening 54, the first bore 51 and the second bore 52 are located in coaxial relation to each other. A step 53 is formed through which the first and second bores 51 and 52 are connected to each other. The step 53 extends substantially perpendicularly to an axis of the component body 50. As illustrated in Fig. 2(A), an annular or circular dish-shaped plate 60 having its outer peripheral dimension or outer diameter D₃ equal to or slightly less than the diameter D₁ at freedom is inserted into the first bore 51 in the component body 50. Subsequently, as shown in Fig. 2(B), the annular dish-shaped plate 60 is urged against the step 53 of the component body 50 by a tubular press tool 70 until the dish-shaped plate 60 is deformed into a planar-plate configuration. As illustrated in Fig. 2(C), when the dish-shaped plate 60 is deformed into the planar and annular element 60', the diameter D₃' of the annular element 60' increases to a value larger than the diameter D₁ of the first bore 51, so that the outer peripheral portion of the annular element 60' is partially bitten to the inner wall of the first bore 51. Thus, the annular element 60' serving as a spring retainer for the end of the valve spring 46, which is remote from the one end of the piston 20, is firmly mounted fixedly to the component body 50. In connection with the above, the dish-shaped plate 60 may be provided at its periphery with a plurality of cut-outs 183, as shown in Fig. 3. In this case, the height h of each cut-out 183 or each projection may be such that, when the dish-shaped plate 60 is deformed into the annular element 60' after force-fitting, all of the projections are bitten to the periphery of the first bore 51. In this connection, the projections may be semi-circular in shape. In the illustrated embodiment, the head section 44 of the poppet valve element 40, which is remote from the end of the passage 24, projects considerably outwardly from the opening of the valve body 12, in order to release the pressure regulating action of the control valve 10 at fail. However, it is dispensed with to project the head section 44 if such fail countermeasure is not required. Fig. 4 fragmentarily illustrates a hydraulic pressure control valve according to another embodiment of the invention. In Fig. 4, components and parts like or similar to those shown in Fig. 1 are designated by the same or like reference numerals, and the description of such like or similar components and parts will be omitted to avoid repetition. In the embodiment illustrated in Fig. 4, a component body 50 is composed of a poppet casing portion 500 and a ring portion 501 serving as a spring retainer. The poppet casing portion 500 has first and second bores 51 and 52 which are connected to each other through a step bore 53. The third bore 502 formed in the poppet casing portion 500 has a slightly larger diameter than the diameter of an end of the piston 20, which is received in the third bore 502. The first through third bores 51, 52 and 502 are arranged in coaxial relation to each other and in concentric relation to the outer periphery of the component body 50. The component body 50 has an inner perripheral groove defined by the outer periphery of the smaller diameter portion 21 of the stepped piston 20, the ring portion 501 and an end of the poppet casing portion 500 remote from the opening 54.The o-ring seal 26b is received in the inner peripheral groove of the component body 50. An o-ring seal 26c is additionally provided in concentric relation to the O-ring seal 26b which is arranged about the outer periphery of the smaller-diameter end 21 of the stepped piston 20. The O-ring seal 26c seals between the periphery of the stepped bore 18 in the valve body 12 and the outer peripheral surface of the poppet casing portion 500. The poppet casing portion 500 has, at its outer periphery, a step 503 to which the end of the valve body 12 adjacent the opening 54 is caulked. The embodiment shown in Fig. 4 is effective in prevention of the O-ring seal 26b around the smaller-diameter portion 21 of the stepped piston 20, from coming out of an annular groove defined by the second bore 52 and the smaller-diameter portion 21. That is, in the embodiment illustrated in Fig. 1, it may be possible for the O-ring seal 26b to move toward the inlet chamber 32, and for the leg 42 of the poppet valve element 40 to get into the groove defined by the second bore 52 and the smaller-diameter portion 21. The embodiment shown in Fig. 4 can effectively prevent this occurring. The invention is applicable to a wide area as a technique in which an annular element is fixedly mounted to an inner periphery of an opening.

Claims: A hydraulic pressure control valve for use with a master cylinder (81) and a wheel cylinder (82), comprising: a valve body (12) formed therein with a stepped bore (18); a piston (20) inserted in said stepped bore (18) for sliding movement therealong; an inlet chamber (32) defined in said valve body (12) on the side of one end of said piston (20) and capable of communicating with said master cylinder (81); an outlet chamber (12c) defined in said valve body (12) on the side of the other end of said piston (20) and capable of communicating with said wheel cylinder (82); passage means (24) formed in said piston (20), said inlet and outlet chambers (32, 12c) communicating with each other through said passage means; a valve element (40) arranged in facing relation to an end of said passage means (24) which is located in facing relation to said inlet chamber (32); and valve spring means (46) for biasing said valve element (40) toward a predetermined position located at the end of said passage means (24), characterised in that said valve body (12) includes, adjacent said inlet chamber (32), an opening (54) , a first bore (51) located at said opening and having a diameter of D₁, a second bore (52) located on the opposite side of said first bore from said opening and having a diameter of D₂, where D₁ is larger than D₂, and a step (53) through which said first and second bores are connected to each other; and that an annular element (60') is fixedly mounted to said valve body (12) in such a manner that an annular dish-shaped plate (60) forming said annular element is urged against said step (53) of said valve body until said dish-shaped plate is deformed into a planar-plate configuration, to bite an outer periphery of said dish-shaped plate (60) to a periphery of said first bore (51), said annular element (60') serving as a spring retainer for supporting an end of said valve spring means (46) which is remote from the one end of said piston (20), the diameter of the central hole of said annular element (60') being less than that of said second bore (52). A hydraulic pressure control valve according to claim 1, characterized in that said valve body (12) is made of metal, and said piston (20) is made of material having an elasticity. A hydraulic pressure control valve according to claim 2, characterized in that said valve body (12) is made of plastic material. A hydraulic pressure control valve according to claim 1, characterized in that said valve body (12) is of one-piece structure. A hydraulic pressure control valve according to claim 1, characterized in that a component body (50) is fixedly mounted to said valve body (12) and is provided therein with said opening (54) and said first and second bores (51, 52). A hydraulic pressure control valve according to claim 5, characterized in that said component body (50) is caulked to said valve body (12). A hydraulic pressure control valve according to claim 5, characterized in that said component body (50) is annular is shape and is provided at its one end with said opening (54), said opening and said first and second bores (51,52) being in concentric relation to an outer periphery of said component body. A hydraulic pressure control valve according to claim 1, characterized in that said step (53) extends substantially perpendicularly to an axis of said valve body (12). A hydraulic pressure control valve according to claim 1, characterized in that said opening (54), said first bore (51) and said second bore (52) are located in coaxial relation to each other. A hydraulic pressure control valve according to claim 1, characterized in that said dish-shaped plate (60) has its diameter at least equal to said diameter D₁ of said first bore (51). A hydraulic pressure control valve according to claim 1, characterized in that said dish-shaped plate (60) is provided at its periphery with a plurality of cut-outs (183). A hydraulic pressure control valve according to claim 5, characterized in that said dish-shaped plate (60) is made of material different from that of which said component body (50) is made. A hydraulic pressure control valve according to claim 1, characterized in that part of the valve element (40) projects through the central hole of said annular element (60').

Inventors: TANAKA RYUICHI, TANAKA, RYUICHI
Applicants: NIPPON AIR BRAKE CO, NIPPON AIR BRAKE CO., LTD.
Application year: 1989
Main classification: F16B21
IPC codes: F16B21, B60T11, B60T8, F16B4