Foot brake module with a guide feature on a relay piston.

Abstract

A valve assembly is provided comprising: an air supply port; an air delivery port; a guide sleeve; and a piston positioned in the guide sleeve and movable between first and second positions to allow air to flow from the air supply port to the air delivery port, wherein a gap is defined between a minor outer diameter of a shaft of the piston and the guide sleeve; wherein the shaft defines an inner bore for passage of air and comprises a plurality of raised surfaces around a circumference of the shaft that narrows the gap and thereby reduces tilting of the piston as it moves in the guide sleeve between the first and second positions. Other embodiments are provided.

Description

1 / 12 Foot brake module with a guide feature on a relay piston. Background

[0001] A foot brake module is a component of a vehicle's braking system, such as a tractor / truck, capable of towing a trailer. Generally, the foot brake module has supply ports to receive compressed air from the vehicle's air reservoirs, distribution ports to supply the received compressed air to the vehicle's braking components, and internal components that control the airflow between the supply and distribution ports in response to the driver's brake pedal actuation. In some vehicles, the supplied air is used to directly effect braking, while in vehicles with an electronic braking system, the supplied air is used as a reserve for the electronic brake control signals generated in response to brake pedal movement. Brief Description of the Drawings

[0002] Figure 1 is a functional view that illustrates how a foot brake module assembly of an embodiment initiates brake actuation.

[0003] Figure 2 is a functional view that illustrates how a foot brake module assembly of an embodiment partially releases the brakes.

[0004] Figure 3 is a diagram of a foot brake module assembly of an embodiment.

[0005] Figure 4 is a cross-sectional view of the foot brake module assembly of Figure 3 when the brake pedal is not pressed and there is no airflow in the primary and secondary circuits of the foot brake module assembly.

[0006] Figure 5 is an exploded view of a part of the foot brake module assembly of Figure 4. Petition 870250080920, dated 09 / 09 / 2025, page 9 / 43 2 / 12

[0007] Figure 6 is a cross-sectional view of Figure 3 when the foot brake pedal is pressed and there is airflow in the primary circuit, but not in the secondary circuit.

[0008] Figure 7 is an exploded view of a part of the foot brake module assembly of Figure 6.

[0009] Figure 8 is a cross-sectional view of Figure 3 when the foot brake pedal is pressed and there is airflow in the primary and secondary circuits.

[0010] Figure 9 is an exploded view of a part of the foot brake module assembly of Figure 8.

[0011] Figure 10 is an exploded view of a part of the foot brake module assembly of Figure 9.

[0012] Figure 11 is an illustration of a secondary piston of a foot brake module assembly in a configuration with a plurality of raised portions.

[0013] Figure 12 is another illustration of the secondary piston in Figure 11, where portions of the secondary piston are shown in dashed lines to illustrate all three raised portions.

[0014] Figure 13 is a variation of the exploded view of Figure 10.

[0015] Figure 14 is a cross-sectional view along line 14-14 in Figure 9.

[0016] Figure 15 is an exploded view of a part of the foot brake module assembly of Figure 14. Summary

[0017] The following configurations generally refer to a foot brake module with a guide feature on a relay piston. In one configuration, a valve assembly is provided comprising: an air supply port; an air supply port; a guide sleeve; and a piston positioned in the guide sleeve and movable. Petition 870250080920, dated 09 / 09 / 2025, p. 10 / 43 3 / 12 between the first and second positions to allow air to flow from the air supply port to the air distribution port, wherein a clearance is defined between a smaller outer diameter of the shaft and the guide sleeve; wherein a piston shaft defines an inner bore for air passage and comprises a plurality of raised surfaces around a circumference of the shaft that narrows the clearance and thus reduces the inclination of the piston as it moves in the guide sleeve between the first and second positions.

[0018] In another embodiment, a valve assembly is provided comprising: primary and secondary supply ports; primary and secondary distribution ports; a guide sleeve; a first piston configured to move in response to the actuation of a brake pedal, wherein the movement of the first piston causes air to flow from the primary supply port to the primary distribution port and causes air to accumulate in a chamber of the foot brake assembly; a second piston configured to move within the guide sleeve in response to the accumulation of air in the chamber, wherein the movement of the second piston causes air to flow from the secondary supply port to the secondary distribution port; and a set of guide features positioned on the second piston to reduce the tilt of the second piston in the guide sleeve.

[0019] In another embodiment, a set of valves is provided comprising: a guide sleeve; a relay piston positioned in the guide sleeve; and means for reducing the inclination of the relay piston as it moves in the guide sleeve.

[0020] Other realizations are possible, and each of them can be used alone or in combination. Detailed Description

[0021] The following embodiments relate to a foot brake module (FBM) assembly (sometimes referred to herein as an assembly). Petition 870250080920, dated 09 / 09 / 2025, p. 11 / 43 4 / 12 foot brake or just foot brake module (FBM)). The FBM assembly can be used on any suitable vehicle, such as, but not limited to, a tractor / truck capable of towing a trailer. Figures 1 and 2 are functional views illustrating the operation of an FBM assembly of one embodiment, initiating brake actuation (Figure 1) and partially releasing the brakes (Figure 2).As shown in these drawings, some of the components of the FBM assembly of this embodiment include, but are not limited to, a thrust member 1 that is configured to be coupled to a foot pedal (not shown), a spring 2, a piston 3, a first inlet 4, a first outlet 5, a first valve body 6, an intermediate (secondary or relay) piston 7, a sealing component 8, a second outlet 9, a third outlet 10, a second inlet 11, a second valve body 12, a first outlet 13, a passage 14, a second outlet 15, primary and secondary distribution ports 21, 22 (sometimes referred to herein as first and second power outlets), primary and secondary supply ports 23, 24 (sometimes referred to herein as first and second power inlets) and a vent 25.Primary and secondary supply ports 23, 24 are configured to be coupled (e.g., via air hoses) to primary (e.g., rear) and secondary (e.g., front) air tanks, respectively. Primary and secondary distribution ports 21 and 22 are configured to be coupled (e.g., via air hoses) to the vehicle's service brakes.

[0022] In operation, when the driver presses the brake pedal, a force is applied to the impulse element 1, which causes air to flow from the primary and secondary supply ports 23 and 24 to the primary and secondary distribution ports 21 and 22. The air exiting the primary and secondary distribution ports 21 and 22 is supplied Petition 870250080920, dated 09 / 09 / 2025, p. 12 / 43 5 / 12 of the various braking components of the vehicle (e.g., the rear and front brakes, respectively). By having primary and secondary supply and distribution ports, the FBM assembly provides two braking circuits (one circuit to control airflow from primary supply port 23 to primary distribution port 21 and another circuit to control airflow from secondary supply port 24 to secondary distribution port 22). As will be discussed in more detail below, in one embodiment, each braking circuit has its own piston that rests on and moves from a valve collar to control the air supply.

[0023] Furthermore, it should be noted that, in some embodiments, the supplied air is used to effect braking directly. In other embodiments (for example, vehicles with an electronic braking system), the supplied air is used as a reserve for the electronic brake control signals, generated in response to the movement of the brake pedal.

[0024] Returning to Figure 1, to initiate braking, when the driver presses the brake pedal, piston 3 is displaced by the impulse element 1 via spring 2. The first valve body 6 is pushed down by piston 3, so that the first inlet 4 of the first brake circuit is opened. Compressed air then flows from the second inlet 11. The pressure in the chamber increases and is transferred to the brake through the primary distribution port 21. When there is a balance of forces on piston 3 between the compression force of the pressure in chamber a and the spring force of spring 2, piston 3 rises until the first inlet 4 is closed by the first valve body 6. Simultaneously, the intermediate piston 7 is moved down by the pressure in chamber b. The valve body of the second circuit is pushed down by the intermediate piston 7, so that the inlet of the second circuit is opened. Compressed air flows from the second body Petition 870250080920, dated 09 / 09 / 2025, p. 13 / 43 6 / 12 of valves 12. The pressure in chamber c increases and is conducted to the brake through the secondary discharge port 22. When there is a balance of forces on the intermediate piston 7, it rises to the neutral position and the intake is closed by the second valve body 12.

[0025] Returning now to Figure 2, when the driver partially reduces the force applied to the brake pedal, the impulse element 1 moves upwards and the spring force 2 on piston 3 decreases. The compression force on piston 3 exceeds the spring force 2, so piston 3 is moved upwards and the first inlet 4 is opened. The pressure in chamber ae, therefore from port 21, is released through outlet 25. When there is a balance of forces on piston 3 between the compression force of the pressure in chamber aea and the spring force 2, piston 3 moves downwards until the first outlet 5 is closed. Simultaneously, the intermediate piston 7 is moved upwards by the pressure in chamber c, prevailing over the pressure in chamber b. The outlet of the second circuit is opened by the intermediate piston 7, so that the pressure in chamber ce, therefore the second discharge port 22, is partially vented.When there is a balance of forces on the intermediate piston 7, the piston moves downwards to the neutral position, and the outlet is closed.

[0026] As mentioned earlier, Figures 1 and 2 present functional views to illustrate the general operation of an FBM assembly. Figure 3 is a perspective view of another FBM 100 assembly of an embodiment with a different door structure from the FBM assembly shown in Figures 1 and 2. As shown in Figure 3, the FBM 100 assembly of this embodiment comprises supports 105 for a brake pedal (not shown), primary and secondary supply ports 106, 107, and primary and secondary distribution ports 108, 109. Figure 4 is a cross-sectional view of the FBM 100 assembly, and Figure 5 is an exploded view of a portion of the Petition 870250080920, dated 09 / 09 / 2025, page 14 / 43 7 / 12 FBM 100 assembly. As shown in Figure 4, in this embodiment, the first circuit of the FBM 110 assembly comprises a primary piston 110 positioned in a primary guide sleeve 111, a primary valve collar 112, and a primary valve seat 113. Similarly, the second circuit of the FBM 110 assembly comprises a secondary piston (relay) 120 positioned in a secondary guide sleeve 121, a secondary valve collar 122, and a secondary valve seat 123.

[0027] In the configuration shown in Figures 4 and 5, the brake pedal is not pressed and there is no airflow in the primary and secondary circuits. That is, in the primary circuit, the primary valve collar 112 is pressed against the primary valve seat 113, preventing airflow from the primary supply port 106 to the primary discharge port 108. Similarly, in the secondary circuit, the secondary valve collar 122 is pressed against the secondary valve seat 123, preventing airflow from the secondary supply port 107 to the primary discharge port 109.

[0028] Figures 6 and 7 illustrate the operation when the brake pedal is pressed and there is airflow in the primary circuit, but not in the secondary circuit. As shown in these drawings, when the brake pedal is pressed, a force is applied to a thrust element to move the primary piston 110 downward, which moves the primary valve collar 112 away from the primary valve seat 113. As indicated in Figures 6 and 7, this creates an opening 115 for airflow from the primary supply port 106 to the primary distribution port 108. At this point, the secondary valve collar 122 is still pressed against the secondary valve seat 123, preventing airflow from the secondary supply port 107 to the primary distribution port 109. However, the downward movement of the primary piston 110 also creates an opening 118 through which air Petition 870250080920, dated 09 / 09 / 2025, page 15 / 43 8 / 12 of the primary supply port 106 fills the chamber containing the secondary piston 120. As shown in Figures 8 and 9, when the pressure in the chamber reaches a limit, the air in the chamber acts as a pilot to push the secondary piston 120 down, which moves the collar of the secondary valve 122 away from the seat of the secondary valve 123. As indicated in Figures 8 and 9, this creates an opening 125 for airflow from the secondary supply port 107 to the secondary distribution port 109, actuating the secondary braking circuit.

[0029] Figure 10 is an exploded view of a part of the FBM 100 assembly of Figure 9. This exploded view shows a clearance 150 between the secondary piston 120 and the guide sleeve 111. Although a clearance of a certain size may be desirable to allow the secondary piston 120 to move within the guide sleeve 111 without friction and wear, it may be undesirable if the clearance size is too large. For example, in some embodiments, the secondary piston 120 is aligned in the first position in Figure 5 and realigns when it reaches the second position in Figure 9, but is susceptible to tilting in the free state between the first and second positions. This tilting may be caused by a moment created by a return spring 170 positioned around the secondary piston 120. In addition, the single sealing ring 180 may create a pivot point that allows the secondary piston 120 to tilt within the guide sleeve 111.When the secondary piston 120 tilts excessively during its stroke, the sealing surface interference disappears on one side of the secondary piston 120, causing air from the primary and / or secondary supply ports 106, 107 to escape through the bottom of the FBM 100 assembly (i.e., opening the exhaust path and allowing airflow to exit through the lower vent), which may be audible. This tilting can also cause wear on the secondary piston 120. Petition 870250080920, dated 09 / 09 / 2025, page 16 / 43 9 / 12

[0030] To help center the secondary piston 120 during its movement and overcome these problems, the return spring 170 can be moved from its location between the secondary piston 120 and the valve seat 123 to a centered area 175 and / or a second sealing ring can be added for stability. However, while these modifications may help center and reduce the tilt of the secondary piston 120, a second sealing ring may retard the movement of the secondary piston 120, while moving the spring 170 may reduce airflow by reducing the diameter of the centered area 175, causing a delay in the application and release of the brakes, which may be undesirable and, in some situations, may cause a delay that prevents compliance with certain timing standards. Another possible solution is to increase the diameter of the shaft portion of the secondary piston 120 to reduce the clearance 150.However, it is possible that the secondary piston 120 may swell due to water absorption, and if the total diameter of the secondary piston 120 shaft is too large, it is possible that the movement of the secondary piston 120 may lock.

[0031] To solve these problems, in one embodiment (see Figures 11 and 12), a plurality of guides (here, raised portions or ribs / fins) 301, 302, 303 are positioned around the circumference of the shaft 200 of the secondary piston 120 and help to guide the secondary piston 120 in the guide sleeve 111 and reduce / limit the inclination. (In Figure 12, the portions of the secondary piston 120 are shown in dashed order to visualize all three raised portions 301, 302 and 303). This provides a solution that combines the best of both worlds. As shown in Figure 13 (which is a variation of Figure 10 for a portion of the secondary piston 120 that has a raised portion), the raised portions narrow the clearance 250 between the secondary piston 120 and the guide device 111. However, as shown in Figures 12, 14, and 15, this narrow clearance Petition 870250080920, dated 09 / 09 / 2025, page 17 / 43 10 / 12 The 250 clearance occurs only in the areas around the circumference of the 200 shaft that have the raised portions (creating a larger outer diameter that limits / reduces the pitch), and the portion of the secondary piston 120 that does not have a raised portion has a larger clearance 150 (see also Figure 10). This narrow clearance 250 limits the pitch of the secondary piston 120 and therefore limits / eliminates audible leaks and regulatory violations in the Commercial Vehicle Safety Alliance (CVSA) inspection of a vehicle. However, the areas around the circumference of the 200 shaft that do not have the raised portions still have the larger clearance 150. That is, as shown in Figures 10 and 13, the secondary piston shaft 120 has a smaller outer diameter in the areas without the raised portions, which creates a larger clearance 150 (Figure 10) than the 250 clearance created by the larger outer diameter in the areas with the raised portions (Figure 13).Thus, the raised portions 301, 302 and 303 provide the desired tilt control, while the non-raised portions prevent the secondary piston 102 from swelling enough to impede the movement of the secondary piston 120.

[0032] In this example shown in Figures 11 and 12, the guide feature has taken the form of three raised portions arranged in an equidistant trilobular pattern around the circumference of the 200 axis of the relay 120 piston to create spaced major outer diameters that limit the inclination of the relay 120 piston within the FBM assembly housing. It should be understood that this is only an example and other implementations may be used. For example, fewer or more than three guide features may be used. Thus, the term assembly is used here to refer to one or more members. In some applications, it may be desirable to use fewer than eight guide features, as if the guide features are too small, they may become trapped in emergent air ports / channels. Petition 870250080920, dated 09 / 09 / 2025, page 18 / 43 11 / 12 guidance in the FBM 100 assembly. However, other applications may not encounter such a limitation. Furthermore, the guide feature assembly can be integrated into the secondary piston 210 during manufacturing or can be added to an already manufactured secondary piston 210 (e.g., using a plastic injection molding tool). The latter has the advantage of not requiring a change in the design of an existing secondary piston and can be machined more easily, since the secondary piston 120 can be manufactured with a smaller tolerance than the guide feature assembly. That is, larger features may be easier to manufacture in a normal spline design, both from the point of view of geometric dimensioning and tolerance and from the point of view of tooling. Again, the guide feature can be included in the secondary piston 120 at any suitable stage.

[0033] It should be understood that all embodiments provided in this Detailed Description are merely illustrative and other implementations may be used. Consequently, none of the components, architectures or other details presented herein should be construed as part of the claims unless expressly mentioned therein. Furthermore, it should be understood that the components shown or described as being coupled (or communicating) with each other may be directly coupled (or communicating) with each other or indirectly coupled (communicating) with each other through one or more components, which may or may not be shown or described herein.

[0034] The above detailed description is intended to be understood as an illustration of selected forms that the invention may take and not as a definition of the invention. Only the following claims, including all equivalents, are intended Petition 870250080920, dated 09 / 09 / 2025, p. 19 / 43 12 / 12 to define the scope of the claimed invention. Consequently, none of the components, architectures, or other details presented herein should be interpreted as part of the claims unless expressly mentioned therein. Finally, it should be noted that any aspect of any of the embodiments described herein may be used individually or in combination with each other. Petition 870250080920, dated 09 / 09 / 2025, p. 20 / 43

Claims

1 / 4 CLAIMS 1. A valve assembly characterized by comprising: an air supply port; an air distribution port; a guide sleeve; and a piston positioned in the guide sleeve and movable between the first and second positions to allow air to flow from the air supply port to the air distribution port, wherein a clearance is defined between a smaller outer diameter of a piston shaft and the guide sleeve; wherein the shaft defines an internal bore for air passage and a plurality of raised surfaces around a circumference of the shaft that narrows the opening and thus reduces the inclination of the piston as it moves in the guide sleeve between the first and second positions.

2. Valve assembly according to claim 1, characterized in that the plurality of raised portions comprises three raised portions.

3. Valve assembly according to claim 2, characterized in that the three raised portions are arranged in a trilobular manner around the circumference of the shaft.

4. Valve assembly according to claim 1, characterized in that the plurality of raised portions comprises less than eight raised portions.

5. Valve assembly, according to claim 1, characterized in that it further comprises a spring positioned around the piston and configured to induce a moment that causes the piston to tilt as it moves in the guide sleeve.

6. Valve assembly, according to claim 1, characterized in that it further comprises a single sealing ring around the piston, such that the single sealing ring is insufficient to prevent the piston from tilting as it moves in the guide sleeve.

7. Valve assembly according to claim 1, characterized in that the air supply and distribution ports and the piston are part of a secondary braking circuit of the foot brake assembly.

8. Valve assembly characterized by comprising: primary and secondary supply ports; primary and secondary distribution ports; a guide sleeve; a first piston configured to move in response to the actuation of a brake pedal, wherein the movement of the first piston causes air to flow from the primary supply port to the primary distribution port and causes air to accumulate in a chamber of the foot brake assembly; a second piston configured to move within the guide sleeve in response to an accumulation of air in the chamber, wherein the movement of the second piston causes air to flow from the secondary supply port to the secondary distribution port; and a set of guide features positioned on the second piston to reduce the inclination of the second piston in the guide sleeve.

9. Valve assembly according to claim 8, characterized in that the set of guide features comprises a plurality of elevated portions.

10. Valve assembly according to claim 8, characterized in that the set of guide features are arranged in a trilobular manner around a circumference of a piston axis. Petition 870250080920, dated 09 / 09 / 2025, p. 22 / 43 3 / 4 11. Valve assembly according to claim 9, characterized in that the set of guide features comprises fewer than eight guide features.

12. Valve assembly, according to claim 8, characterized in that it further comprises a spring around the second piston which is capable of inducing a moment to cause the second piston to tilt in the guide sleeve.

13. Valve assembly according to claim 8, characterized in that it further comprises a single sealing ring around the second piston, such that the sealing ring is insufficient to prevent the second piston from tilting in the guide sleeve.

14. Valve assembly according to claim 8, characterized in that the set of guide features are manufactured with the second piston.

15. Valve assembly according to claim 8, characterized in that the guide feature assembly is added to the second piston after the second piston has been manufactured.

16. Valve assembly characterized by comprising: a guide sleeve; a relay piston positioned in the guide sleeve; and means for reducing the inclination of the relay piston as it moves in the guide sleeve.

17. Valve assembly according to claim 16, characterized in that the means for reducing inclination comprise a plurality of raised surfaces along a circumference of a relay piston axis.

18. Valve assembly according to claim 17, characterized in that the plurality of raised surfaces are arranged in a trilobular pattern. Petition 870250080920, dated 09 / 09 / 2025, page 23 / 43 4 / 4 19. Valve assembly, according to claim 16, characterized in that it further comprises a spring positioned around the relay piston so as to induce a moment that causes the relay piston to tilt as it moves in the guide sleeve.

20. Valve assembly according to claim 16, characterized in that it further comprises only a single sealing ring around the relay piston, which is insufficient to prevent the relay piston from tilting as it moves in the guide sleeve. Petition 870250080920, dated 09 / 09 / 2025, p. 24 / 43

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