TECHNICAL FIELD

The present invention relates generally to inline proportioning valves, and more specifically to inline proportioning valves located between the master cylinder and the wheel cylinders in a hydraulic braking system for a vehicle.

BACKGROUNDART

It is commonly known in the art to provide inline proportioning valves in vehicle braking systems for proportioning the application of pressure to front and rear brakes. One such inline proportioning valve is shown in U.S. Patent No. 4,893,878 to Cole. In this patent, the valve is constructed with a one-piece housing threaded directly into a port on the master cylinder and provided with an outlet port at the opposite end of the housing. The exterior of the housing includes a groove receiving an O- ing which overlies a radially extending vent passageway communicating with the interior chamber within the housing. A spring biased piston is positioned in the chamber together with a removable insert and poppet associated with a passage through the piston with these components retained in place by retaining ring structures, springs and the like and sealed by O-ring seals. The construction of the housing and piston enables increased expansion volume which provides for an increased pressure drop downstream of the valve when the pressure is released upstream of the valve. The one- piece housing and insert enables the housing to be

machined from the poppet, thereby providing ease of manufacture and assembly.

However, there are certain problems with this design. The installation of a retaining ring is subject to operator skill, and may result in creation of small contaminants when the retaining ring scrapes along the side of the anodized bore in the housing. Also, the insert, including the spring, is not provided as a subassembly, thus increasing manufacturing costs.

Accordingly, it would be desirable to develop an inline proportioning valve assembly in which the insert and spring were provided as a subassembly, and the retaining ring was not required for retaining the internal components, thus eliminating contaminants.

DISCLOSURE OF INVENTION

An object of the present invention is to provide an inline proportioning valve for use in a vehicle braking system having a one-piece housing in which an insert is provided as a subassembly and no retaining ring is required.

Another object of the present invention is to provide an inline proportioning valve with improved manufacturing capability and reduced manufacturing costs.

Accordingly, an improvement for an inline proportioning valve for a hydraulic brake system of a vehicle is provided, the vehicle having: a housing having first and second ends, the first end adapted for connection with a master cylinder of the brake system and the second end of the housing adapted to be

connected with a fluid flow line extending to the vehicle wheel cylinders, the housing forming an axial inlet port in the first end and an outlet port in the second end, the housing including a plurality of axially extending chambers in communication with each other with each chamber being of cylindrical configuration and decreasing in diameter from the inlet port to the outlet port, the housing including three chambers with a peripheral, radially extending shoulder at the juncture between adjacent chambers, a differential area piston positioned in the chambers in sealed relation thereto, the piston including an axial passageway therethrough, the piston including a larger pressure contact area in the chamber adjacent the outlet port than the pressure contact area in the chamber adjacent the inlet port whereby pressure passing through the passageway in the piston will react against the piston to force the piston towards the inlet port due to the differential contact areas, a calibrated spring biasing the piston toward the outlet port to resist movement of the piston toward the inlet port, the chamber adjacent the inlet port including an insert engaging the shoulder at the inner end of the chamber adjacent the inlet port with the insert forming a closure for the chamber adjacent the inlet port and including a central opening guidingly receiving the piston with the diameter of the portion of the piston guided by the insert being smaller than the diameter of the piston received in the chamber adjacent the outlet port, a valve member mounted in the insert in normally open relation to the passageway through the piston to enable pressure flow through the piston, the valve member closing the passageway through the piston when the piston moves toward the inlet port to control and stop flow through the passageway when the differential piston is moved a predetermined distance toward the inlet port by compressing the calibrated

spring means, the housing including a radial vent passage communicating with the central chamber in the housing, and means for maintaining the engagement of the insert with said shoulder at the inner end of the chamber adjacent the inlet port, the improvement in the maintaining means comprising: staking means integrally on one of the housing and the insert engaging the other of the housing and the insert, whereby to retain the insert in the housing without additional means.

Also provided is an inline proportioning valve comprising: a housing having first and second ends thereof and having a plurality of cylindrical chambers formed axially therethrough in communication with each other; a subassembly located within said chambers; and wherein said subassembly is staked into position within the chambers by deforming a portion of the first end of the housing sufficiently radially inwardly adjacent the subassembly to hold said subassembly within said housing.

These together with other objects and advantages will become apparent to one skilled in the art upon review of the detailed description of the invention, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 shows a vertical cross-sectional view of an inline proportioning valve in accordance with U.S. Pat. No. 4,893,878.

FIGURE 2 shows a vertical cross-sectional view of an inline proportioning valve in accordance with the present invention.

FIGURE 3 shows a blown up cross-sectional view of a staked housing and insert in accordance with the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows a vertical cross-section of the prior art reference U.S. Patent No. 4,893,878. This valve is used in a hydraulic vehicle braking system for proportioning the application of fluid pressure to front and rear brake cylinders. The interior components of the inline proportioning valve of this reference are held into place by means of the retainer ring 10. In order to avoid the problems discussed above with respect to said retainer ring, the present invention is provided as shown in FIG. 2.

Referring to FIG. 2 , an inline proportioning valve 20 is shown in accordance with the present invention. The valve 20 includes a one-piece housing 22 which has one end 24 which is smaller in peripheral circumference and provided with external threads for threaded engagement into a master cylinder of a braking system. The other end 26 of the housing includes an internally threaded outlet 28 which has a beveled or chamfered peripheral edge 30 which extends to a central passageway 32 having a diameter substantially less than the internally threaded outlet 28. The outlet 28 is connected to a hydraulic conduit extending to a wheel cylinder in the hydraulic brake system.

The housing includes a first cavity 34 extending longitudinally axially therein and in communication with the outlet 28. The housing 22 further includes second and third cavities 36,38 formed longitudinally axially therein in communication with the

first cavity 34. A differential area piston 40 is received within the cavities 34,36,38 and includes a peripheral outwardly extending flange 42 intermediate the ends of the piston for engagement with a shoulder 44 between the first cavity 34 and second cavity 36. The upper end of the piston includes a peripheral shoulder 46 which is slidably received in the chamber 34 and projects slightly outwardly from the circumference of the upper end portion 48 of the piston. An O-ring seal 50 is engaged with the upper surface of the flange 46 and is retained in place by outlet pressure. A peripheral flange or rib 52 on the upper end of the piston retains the O-ring 50 on disassembly.

The piston 40 includes a lower end 54 of reduced diameter which is received in an opening 56 in the top wall 58 of the insert 60, with the juncture between the larger diameter portion of the piston and the smaller diameter portion of the piston defining a shoulder 62. A calibrated coil spring 64 is positioned within the second cavity 36 and has its ends abuttingly engaging the flange 42 on the piston and the top wall 58 of the insert 60, respectively, to bias the flange 42 against the shoulder 46. The second cavity 36 also includes a radially extending vent passage 66 communicating with a peripheral groove 68 in the exterior of the housing 22 with a second O-ring seal 70 being positioned in the groove 68 and forming a closure for the vent passage 66 with pressure in the vent passage 66 causing the O-ring seal 70 to move outwardly in the groove sufficiently to vent the pressure from the passage 66.

A third O-ring seal 72 seals the insert 60 with respect to the interior of the third chamber 38.

Also, a fourth O-ring seal 74 is interposed between the exterior of the reduced diameter 54 of the piston and

the interior surface of the chamber 76 of the interior of the insert 60. A poppet 80 is positioned and housed within the insert 60 and includes an inner rounded peripheral edge 82 engageable with the seal 74. The outer periphery 84 of the poppet is received within an enlarged cylindrical chamber or cavity 86 in the insert 60 with a shoulder 88 being provided at the juncture between the chamber 86 and the chamber 76 which form the interior of the insert 60. The bottom portion 90 of the poppet 80 includes openings or passageways to allow flow therethrough and is disposed slightly below the periphery 84 with a conical spring 92 engaging the periphery of the bottom portion 90 of the poppet with the conical spring also engaging an internal lip 94 of the insert.

The insert, including the conical spring 92 is provided as a subassembly. This subassembly is inserted into the third cavity 38, and a lower portion 96 is staked sufficiently radially inwardly over the lower portion 98 of the insert in order to hold the insert in position. In this manner, the problems encountered with respect to the prior art discussed above are avoided, and the insert, including the conical spring 92, may be provided as a subassembly. This may greatly decrease the cost and increases ease of manufacturing, while improving quality control by eliminating the error involved in operator assembly of the former retainer ring, eliminating contaminants, and providing a convenient subassembly operation.

While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments

-S - for practicing the invention as defined by the following claims.