Trailer braking system

Abstract

A trailer brake valve module has a valve unit with a circumferential wall having a wall section 32 and a resilient leg 31 able to snap into a groove or undercut (40, fig 3a) on a valve body to fix the

Description

The invention relates to a brake module, in particular for a towed vehicle such as a three axle semi-trailer or full trailer. In known trailer brake modules, the brake valve unit is fixed between two separate or divided bodies, which are either screwed to each other or joined with a circlip. DE102016116516 discloses a known type of trailer brake system relay valve in which the brake system includes a main valve unit; a pilot-control valve unit that is fluidically connected to the main valve unit; and a two part housing to accommodate at least the main valve unit and the pilot-control valve unit. The pilot-control valve unit includes a double solenoid unit and at least one valve device, in which the double solenoid unit is formed such that it can be populated with at least one valve device, and in which the double solenoid unit has at least two accommodating portions for accommodating valve devices and at least two solenoid devices for actuating the valve devices. CN108248591 discloses a further valve arrangement for a trailer brake system. The integrated EBS trailer valve comprises a valve body assembly, an upper cover assembly and a throttling piston assembly. A pressure sensor and an electromagnetic valve assembly are arranged in the trailer valve. In use the electromagnetic valve assembly can control the pressures in a trailer brake chamber and the trailer brake chamber pressure is monitored in real time through the pressure sensor. WO2019158498A1 discloses a trailer control valve for a trailer of an utility vehicle, having at least one housing and at least one housing insert guided in the housing, and having at least one trailer control valve piston with a cylinder section and a collar section, wherein the collar section of the trailer control valve piston is guided in the housing insert in at least a first position at least partially in a receptacle, wherein at least one non-return valve and at least one throttle bore are provided in the region of the receptacle. In the known solutions the_valve unit is formed between two bodies which are either screwed together or fixed by a separate circlip. These solutions are technically reliable but suffer from complexity in their assembly and require a number of components, which results in a length assembly time. However, in the highly competitive field of trailer braking systems there is constant demand for lower costs both in acquisition, operation and in lifetime maintenance of the brake system. The present invention therefore seeks to provide a valve arrangement in a trailer brake module which addresses the lifetime costs of the valve. According to a first aspect of the invention there is provided a brake valve module comprising a valve unit and valve body, wherein the valve unit is provided with a leg adapted to engage with a groove or undercut on the valve body in accordance with the characteristics of Claim 1. According to a second aspect of the invention there is provided a removal tool adapted to remove the valve unit from the valve body comprising a leg having a surface adapted to engage with the valve unit and move a retaining leg on the valve unit out of engagement with the valve body. Preferably, the valve unit comprises a plurality of legs. Further preferred aspects of the invention can be found in the sub-claims The invention advantageously provides a new fixation concept with a snapped-in connection, with which the valve unit can be self-locking in the body of the trailer brake module, but which further allows for the possibility of disassembling the valve unit in contrast to known solutions. The solution of the invention provides a more compact design, with easier, simpler assembly. Additionally, fewer components are required to fix the two parts so that the cost of the solution is reduced compared to known solutions. An exemplary embodiment of the invention will now be described in greater detail in which: Fig. 1 shows a valve arrangement in a monoblock housing; Fig. 2 shows a plan view of the internal side of the relay valve unit; Fig. 3a shows schematically the valve unit prior to insertion into the valve; Fig. 3b shows the valve unit after insertion; Fig. 4 shows a plan view of a removal tool Figs. 5a-c show the removal tool in use. Figure 1 shows schematically the arrangement of the valve comprising a relay piston unit 30, which valve arrangement is provided with pneumatic inputs for the main supply pressure 1, a control pressure 4 and an air bellow pressure 42. The valve arrangement is further provided with output ports for an exhaust 3 and to the brake chambers 21. Four brake chambers are indicated by way of example as this is commercially the commonest arrangement for a trailer brake system but the invention would be applicable to trailer brake systems in which three axles (eg 6S4M) or only one axle (eg 2S1M) are braked. The main supply pressure 1 is pneumatically connected to the input of a relay valve 30. The control pressure 4 is connected to the input of the back up solenoid. The relay valve 30 is provided with a first pneumatic output to the brake chambers 21 and a second pneumatic output to the exhaust 3 and to the input of the exhaust solenoid. The outputs of the load solenoid, back up solenoid and exhaust solenoid are connected to the pilot input of the relay valve 30. The relay valve unit is formed from a flexible material such as plastic and is provided with six legs 31 on the valve unit, which are configured to be able to snap into a groove formed on the valve body. This ensures a robust fixation solution whilst allowing for disassembly as outlined in more detail below. A pressure control valve assembly being a combination of two 2 / 2 solenoid valves, one of which is normally open and the other normally closed, controls the flow of air to the brake chambers. The solenoid valve receives inputs from the air bellow pressure input and the main supply pressure and the solenoid receives an input from the output of the relay valve 30. The output of the solenoid is connected to a pressure transducer, which measures the pressure out of the relay valve 30. The control pressure input is further connected to a second pressure transducer. Figure 1 shows the valve arrangement of the invention in a monoblock housing 70, with the main supply pressure port 1, the control pressure port 4 and the air bellow pressure port 42. The main pressure supply port 1 is arranged in a face of the housing perpendicular to the face with the inputs of the control pressure port 4 and air bellow pressure port 42. The outputs to the brake chambers 21 can be seen disposed perpendicularly to both of the faces. The relay valve exhaust is also arranged in the same face as the control pressure port input 4 and air bellow input port 42. Figure 2 shows a plan view of the internal side of the relay valve unit. The exterior circumferential wall of the valve unit comprises six legs 31, which alternate with six wall portions 32 around the circumference of the valve unit with a small gap between each leg 31 and each wall portion 32. Each leg 31 comprises three sections. The two outer sections 33 have a greater thickness than the centre section 34 and have an angled profile so that the section is angled slightly outwardly so that the respective distal end lies slightly outside of the vertical plane of the circumferential wall 35. The centre section lies substantially in the vertical plane if the circumferential wall. The interior face of the centre section is provided with an undercut or groove. The height of each leg 31 is less than the height of the adjacent wall portion 32. A further annular, contiguous wall 36, concentric with the exterior wall is provided having a height slightly less than the height of each leg 31. The annular wall has a profile such that the spatial separation of the segment of the wall concentric with the wall portions 32 is less than the spatial separation of the segment of the wall concentric with the legs 31. This results in a pocket 37 being formed in the space between the leg and the annular wall. A further concentric annular wall having a smaller radius than the first annular wall is provided as part of the relay valve functionality. Figures 3 a and 3b show schematically the valve unit prior to and after insertion into the valve body. The valve body is provided with an undercut 40, which receives the leg 31 after insertion of the valve unit to provide a snap fit type connection between the valve unit and the valve body. There is a space above the leg in the installed position of the valve unit between the circumferential wall and the interior surface of the valve body. Figure 4 shows a plan view of the removal tool, which has a generally circular or disc shape with six protruding segments. Six substantially equidistantly spaced legs 60 depend substantially perpendicularly from the disc from around the centre of the protruding segments. Each leg is provided with a series of claws 61, which claws are angled towards the disc. Figures 5a, 5b and 5c show the removal tool in use. In Figure 5a, the tool is shown before entry into the combined valve unit and body. In Figure 5b, the tool has entered the space and engaged the leg 31 pushing the leg towards the centre of the valve unit and away from engagement with the undercut. The valve unit can then be removed from the valve body as shown in Figure 5c. Although the removal tool leg is described as being provided with claws, other techniques, in particular using friction would be possible. Although the invention has been specifically described as having six legs, other numbers of legs would be possible. This invention is useable typically in trailer brake modules, drain valves or pressure limiting valves. Trailer in the context of the invention is a trailer of category 03 or 04, that is trailers over 3.5 tonnes. At this time, the standards in force are ISO 1185:2003 ISO 7638-1 / 2:2018, ISO 11992:2021,18012098:2020 and SAE 560:2020.

Claims

1. A brake valve module comprising a valve unit and valve body, wherein the valve unit is provided a circumferential wall having a wall section and a leg, which leg is adapted to engage with a groove or undercut on the valve body to fix the valve unit in a fixed position in the valve body, wherein the leg is resilient such that its position can be moved between a position of engagement with the groove or undercut to a disengaged position.

2. A brake valve module according to Claim 1, wherein the leg comprises three sections, the two outer sections having a greater thickness than the centre section and have an angled profile so that the section is angled slightly outwardly so that the respective distal end lies slightly outside of the vertical plane of a circumferential wall of the valve unit.

3. A brake valve module according to Claim 2, wherein the centre section lies substantially in the vertical plane if the circumferential wall.

4. A brake valve module according to Claim 2 or Claim 3, wherein the interior face of the centre section is provided with an undercut or groove.

5. A brake valve module according to any one of Claims 1 to 4, wherein the valve unit further comprises an annular, contiguous wall having a profile such that the spatial separation of the segment of the wall concentric with the wall portion is less than the spatial separation of the segment of the wall concentric with the legs.

6. A brake valve module according to any one of Claims 1 to 5, wherein a pocket being formed in the space between the leg and the annular wall.

7. A brake valve module according to any one of Claims 1 to 6, wherein the valve unit comprises a plurality of wall sections and legs arranged in an alternating manner.

8. A brake valve unit according to Claim 7, wherein the valve unit comprises six legs.

9. A removal tool adapted to remove the valve unit from the valve body of the brake module according to any one of Claims 1 to 8, comprising a leg having a surface adapted to engage with the valve unit and move a retaining leg on the valve unit out of engagement with the valve body.

10. A removal tool according to Claim 9, comprising a plurality, preferably six legs.

11. A removal tool according to Claim 9 or Claim 10, wherein the or each leg is provided with a series of claws or a frictional surface, which claws or frictional surface are angled towards the disc.

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