Unloading valve assembly with integrated safety valve

Abstract

An unloading valve assembly (102) for a compressed air supply system (100), in particular for a compressed air supply system of a vehicle, the unloading valve assembly (102) comprising an unloading valve (104) comprising a piston (106) and a first spring (108), the piston being configured to move between a seated position on a first valve seat (110) and a first unseated position against a biasing force of the first spring (108), the unloading valve assembly (102) further comprising a safety valve (130) configured to be activated when a pressure in an inlet passage (114) exceeds a first predetermined condition to direct compressed air received via the inlet passage (114) to a discharge passage (116).

Description

Technical Field

[0001] This invention relates to an unloading valve assembly with an integrated safety valve in a globally scalable air handling system, and more particularly to an unloading valve assembly including an integrated safety valve for a vehicle compressed air supply system. Background Technology

[0002] Vehicle air compressors are configured to pressurize and deliver compressed air for various purposes in a vehicle, such as operating pneumatic tools, inflating tires, or assisting in the operation of the vehicle's braking system.

[0003] Air compressors typically operate in conjunction with air dryers (such as air dryer filters) and unloading valves to ensure the proper functioning and maintenance of the compressed air supply. Compressed air is stored in a receiver tank until needed, such as for use in actuating vehicle braking systems.

[0004] The compressed air supply system also includes a pressure control system to regulate the pressure of the compressed air within the desired range. The pressure control system includes various components such as pressure sensors, valves, and regulators.

[0005] Compressed air contains moisture and, in some cases, contaminants such as oil or dirt. Air dryers are configured to remove moisture and filter out these contaminants from the compressed air. Air dryers typically contain a desiccant material that absorbs moisture, ensuring a supply of dry, clean air to the vehicle's braking system. However, the absorption capacity of an air dryer (i.e., the desiccant material) is limited and must be regenerated. The regeneration process involves removing the moisture accumulated in the desiccant material used in the dryer. This helps restore the air dryer's drying capacity. To this end, a portion of the compressed air from the compressed air system is directed back through the air dryer. This process is typically controlled by a valve mechanism included in the air pressure control system. The dry air flows in the opposite direction across the desiccant bed, effectively purging the moisture absorbed by the desiccant material. The moisture-laden air is then exhausted from the system, while the dry air continues to flow back into the main air system for further use.

[0006] Air compressors typically operate in either loaded or unloaded mode.

[0007] In load mode, the air compressor remains actively engaged and continuously compresses air into the air tank and / or reservoir via the air dryer. This mode is typically used when compressed air demand is high or when the vehicle requires a constant supply of compressed air for tasks such as heavy-duty pneumatic tools or continuous brake assist.

[0008] In unloading mode, the air compressor disengages from the compression process when the demand for compressed air decreases or stops.

[0009] Regarding the operation of air compressors, the main function of the unloading valve is to unload the air compressor when the demand for compressed air in the compressed air supply system decreases or stops.

[0010] An unloading valve is typically located near the air compressor and connected to both the air compressor and the air tank. When the pressure in the air tank reaches its maximum level, the unloading valve opens, diverting compressed air from the compressor and allowing excess air to escape (e.g., into the atmosphere). This prevents the air system from becoming overpressurized and extends the life of the air compressor.

[0011] An example of a known unloading valve 104 for a compressed air supply system 100 used in a vehicle (e.g., a vehicle's braking system) is shown. Figure 1 The unloading valve 104 is configured to release pressurized compressed air when demand decreases or air supply is no longer required (e.g., for a braking system).

[0012] The unloading valve 104 is accordingly configured to unload the pressurized air received from the air compressor (not shown) via the inlet passage 114 and discharge it into the atmosphere via the discharge passage 116.

[0013] The unloading valve 104 includes a piston 106 (including a piston head 122, a piston body 124, and a piston pin 126) and a (first) spring 108. The piston head includes an annular groove (around its periphery) for retaining a first sealing ring 146. The piston body includes a recess for retaining a second sealing ring 148.

[0014] The piston 106 is arranged in the main chamber and configured (along the central axis 112) to move between a seated closed position and an unseated open position against the biasing force of the first spring 108 on the valve seat. The unloading spring force is configured to hold the piston in the closed position (or state).

[0015] During the regeneration process of the air dryer, moisture-laden air enters the main chamber through the inlet channel. The pressure control system is configured to activate the unloading valve via a pressure control signal to release the moisture-laden air into the atmosphere.

[0016] The unloading valve is then activated (i.e., opened) upon receiving control pressure via control channel 118, which acts on the piston head. That is, the resultant force acting on the piston (i.e., the force applied via the inlet channel and the control channel) exceeds the spring force and opens the unloading piston. This operation of the unloading valve is referred to as the normal mode.

[0017] During the opening operation of the unloading valve, a so-called stick-slip effect occurs in the sealing rings / elements, particularly the first sealing ring. This phenomenon causes a pressure increase in the inlet passage, so that once the surface friction of the first sealing ring is overcome, the unloading valve spontaneously opens fully (due to the sudden and rapid movement of the piston in the chamber), resulting in a sudden pressure loss and / or even pressure collapse in the air supply system.

[0018] The unloading valve incorporates safety measures to address malfunctions in the air supply and / or pressure control systems. For example, in one scenario, a pressure control system failure causes the compressor to pump air beyond required levels, compromising the pressure resistance of downstream components. In another scenario, for instance, a pressure control system failure causes the air compressor to operate in load mode but compressed air flow is blocked, preventing delivery of compressed air to the air tank and / or compressed air reservoir. This operation of the unloading valve is referred to as the safety mode.

[0019] In the event of a malfunction in the air supply system or pressure control system, there is no available control pressure in the control channel, and the pressure of the compressed air in the inlet channel increases. This generates an unbalanced force that acts on the piston, i.e., the piston body (in...). Figure 2 (Displayed as a dotted-dash arrow).

[0020] This imbalance in force distribution arises from the different surface areas of the piston head and piston body at the point of pressure application, particularly the difference in surface area between the first and second sealing elements that hold the piston in place. The unloading valve eventually opens when the net force acting on the piston exceeds the spring force.

[0021] However, as soon as the piston begins to move, the leaking pressurized air immediately expands significantly because the cross-section of the flow path provided by the discharge passage after the valve seat is larger than the cross-section at the valve seat (in...). Figure 2 (Illustrated by arrows of varying sizes). This characteristic (non-uniform flow distribution) results in the unloading valve opening slightly because the piston's movement is limited by the spring force acting upon it. Therefore, the unloading valve is disadvantageously kept (mostly) in a leak-like state (partially open / partially closed). This, in turn, limits the amount of pressurized air that can be released through the unloading valve.

[0022] Another drawback of the aforementioned known leakage state of the unloading valve is that, at a given air flow rate, even though the unloading valve is open, the pressure in the compressed air supply system (e.g., a braking system) begins to increase. Summary of the Invention

[0023] Therefore, the object of the present invention is to overcome the shortcomings of known unloading valves. In particular, an improved unloading valve assembly is provided, which can operate in a reliable and controllable manner.

[0024] Advantageously, the unloading valve assembly according to the invention is configured to operate in a more reliable safety mode, which provides a smooth switch between the open and closed states of the unloading valve, i.e., it prevents the unloading valve assembly from opening and / or closing abruptly.

[0025] In addition, the flow distribution of compressed air through the unloading valve assembly was improved.

[0026] This objective is achieved in this invention by the unloading valve assembly according to claim 1. Therefore, an unloading valve assembly for a compressed air supply system, particularly for a vehicle's compressed air supply system, is provided. The unloading valve assembly includes: The unloading valve assembly includes an unloading valve. The unloading valve includes a piston and a first spring, and The piston is configured to move against the biasing force of the first spring between a seated position and a first unseatped position on the first valve seat. The unloading valve assembly also includes a safety valve. The safety valve is configured to be activated when a first predetermined condition in the inlet channel is exceeded by compressed air, so as to guide the compressed air received via the inlet channel to the discharge channel.

[0027] Further aspects and preferred embodiments are defined in the appended dependent claims.

[0028] The present invention is based on the following concept: the unloading valve assembly includes an unloading valve and an integrated safety valve, that is, it combines multiple valve functions that can be performed by different valve devices, preferably through an integrated overall design.

[0029] The unloading valve includes a piston and a first spring, wherein the piston is configured to move against the biasing force of the first spring between a seated position and a first unseatped position on a first valve seat. The safety valve is configured to be activated when the pressure in the inlet passage exceeds a first predetermined condition (e.g., a given pressure level) to direct compressed air received via the inlet passage to a discharge passage.

[0030] For example, a safety valve is configured to be activated when the amount / volume of compressed air filling the inlet chamber and acting on the piston, particularly the air pressure level generated by the compressed air, exceeds a (first) predetermined level, so as to direct the compressed air received via the inlet passage to the discharge passage.

[0031] Specifically, the unloading valve is configured to receive compressed air via an inlet channel and control pressure via a control channel, wherein in the first seated position, the unloading valve is closed to prevent compressed air from escaping through the discharge channel, and in the unseated position, the unloading valve is open to allow compressed air to escape through the discharge channel.

[0032] Advantageously, the safety valve is configured to be activated, for example, by a pressure rise in the inlet passage, such as when airflow in the air supply system is blocked upstream of the compressor and / or air dryer, or when the pressure control system fails to apply pressure control, causing the unloading valve to remain closed despite reaching a first predetermined condition (e.g., maximum pressure level).

[0033] Specifically, the safety valve is arranged within a piston chamber defined within the piston of the unloading valve. This results in a compact and cost-effective design, and makes it easier to control the flow path or distribution of compressed air. Advantageously, a uniform (or symmetrical) flow distribution within the piston chamber is achieved.

[0034] Specifically, the piston chamber includes an outlet passage configured to communicate with the discharge passage. This allows for better control of the flow parameters of the compressed air leaving the unloading valve assembly.

[0035] Specifically, the piston includes a piston passage configured to guide compressed air into the piston chamber. This allows for a symmetrical flow path / distribution of the compressed air acting on the safety valve.

[0036] Specifically, the safety valve includes a valve stem and a second spring acting on the valve stem to hold the safety valve in the closed position, wherein in the closed position, the safety valve is configured to prevent compressed air from entering the piston chamber. This provides a reliable safety valve where the opening (activation) of the safety valve can be easily and precisely adjusted by calibrating the (second) spring force, for example, depending on a control pressure signal.

[0037] Specifically, the valve stem is configured to move along the central axis and against the biasing force of the second spring between a seated position and a second unseatped position on the second valve seat, wherein the stem valve is configured to be moved / moved by a force generated by compressed air guided into the piston chamber.

[0038] Specifically, the valve stem includes a head portion. Preferably, the head portion includes a recess for receiving a sealing element.

[0039] Specifically, the safety valve includes a buffer chamber for maintaining compressed air in a first open state mode within the piston chamber, preferably in which the compressed air provides (has reached or satisfied) a first predetermined condition. For example, in the first open state mode, the pressure of the compressed air acting on the safety valve (or stem valve) exceeds a predetermined level, preferably a (air) pressure level.

[0040] Specifically, the buffer chamber includes a chamber disposed (defined) between the outer periphery of the head portion of the stem valve, particularly the outer periphery of the head portion, and the inner periphery of the piston chamber.

[0041] Specifically, the buffer chamber is formed by a gap or space provided between the inner periphery of the piston and the outer periphery of the head portion of the valve stem.

[0042] Specifically, the head portion of the stem valve includes dimensions configured to prevent compressed air from entering the piston chamber.

[0043] Specifically, in the first open state mode, the valve stem is configured to move within the piston chamber, thereby allowing compressed air to accumulate in a buffer chamber defined between the outer perimeter of the head portion and the inner perimeter of the piston chamber.

[0044] Specifically, no sealing element is provided between the inner circumference of the piston and the perimeter of the valve stem head portion that closes the buffer chamber. A gap exists between the inner circumference of the piston and the perimeter of the valve stem head portion. For example, the gap is approximately 0.07, 0.06, 0.05, or 0.04 mm. This gap is configured to act as a nozzle, preventing rapid and sudden pressure loss, thereby allowing pressure to build up in the buffer chamber. Specifically, the pressure buildup in the buffer chamber triggers a second open state mode of the safety valve.

[0045] Specifically, the safety valve is configured to acquire a second open state mode when the compressed air in the buffer chamber exceeds a first predetermined condition, and in particular, a second predetermined condition is provided. For example, to achieve the second state mode, the pressure of the compressed air acting on the stem valve may exceed a second level, such as a second (air) pressure level.

[0046] Specifically, in the second open state mode, the valve stem is configured to move, thereby guiding compressed air through the outlet passage to the discharge passage.

[0047] Specifically, the piston also includes a piston head, a piston body, and a piston pin. Preferably, the piston pin is detachably fixed to the piston body. For example, the piston pin is screwed onto the inner circumference of the piston body.

[0048] Specifically, the piston body includes a first hole and a second hole, and the piston pin includes a third hole. Preferably, the first hole, the second hole, and the third hole together define a piston chamber for receiving the safety valve.

[0049] Specifically, the piston head includes a groove on its outer periphery for receiving the first sealing ring.

[0050] Specifically, the piston body includes a recess on its outer periphery for receiving the second sealing ring.

[0051] In particular, the unloading assembly also includes retaining elements, such as a metal retaining disc, for securing and holding the second sealing ring in place.

[0052] Specifically, the second sealing ring has a square cross-section.

[0053] In particular, the combination of the square cross-section of the second sealing ring and the fixing element further enhances the positioning of the second sealing ring 148 and improves its performance over time. Advantageously, this method ensures that if the gasket or sealing ring expands due to contact with corrosive media, the fastening mechanism will still prevent the seal from shifting, thereby preventing failure. Attached Figure Description

[0054] Figure 1 An unloading valve for a compressed air supply system in a closed state, according to existing technology; Figure 2 An unloading valve for a compressed air supply system in the open state mode according to existing technology; Figure 3 For the unloading valve assembly including an unloading valve and a safety valve according to the present invention, the safety valve is indicated to be in the closed state (not activated); Figure 4 For the unloading valve assembly including a safety valve according to the present invention, the safety valve is indicated to be in the open state mode (activated); Figure 5 A schematic partial view of the unloading valve assembly according to the present invention, indicating the safety valve in a first open state mode; Figure 6 A schematic partial view of the unloading valve assembly according to the invention, indicating the safety valve in a second open state mode; and Figure 7 A schematic partial view of the unloading valve assembly according to the present invention, indicating the piston and sealing element. Detailed Implementation

[0055] Figure 1 and 2 The unloading valve 104 of the compressed air system according to the prior art is schematically shown in closed and open states (as described above).

[0056] The unloading valve 104 is configured to receive compressed air via the inlet passage 114.

[0057] The unloading valve 104 is also configured to receive a control pressure signal via the control channel 118.

[0058] In the closed state, the piston 106 of the unloading valve 104 is sealed on the first seat valve 110.

[0059] Specifically, in the closed state, the (pressurized) compressed air cannot escape through the unloading valve 104 into the discharge passage 118 (e.g., into the atmosphere).

[0060] Specifically, the first seat valve 110 is formed by a protrusion formed on the periphery of the main chamber.

[0061] In the open state mode, piston 106 moves along central axis 112 in the main chamber to a first unseat position, thereby allowing compressed air to flow... Figure 2 It escapes through the emission channel 118 as shown.

[0062] In particular, the compressed air has an unfavorable non-uniform flow distribution, which changes as the compressed air is directed to the discharge channel 116 (shown by arrows of different sizes).

[0063] In particular, once compressed air enters the discharge channel (which is, for example, at atmospheric pressure), flow parameters (such as velocity, pressure, and density) change significantly.

[0064] This unstable flow of compressed air adversely affects the operation of the unloading valve 104.

[0065] Specifically, the unloading valve cannot be fully opened (i.e., in the fully open mode) because the spring force pushes the piston against the first valve seat 110 due to the sudden pressure drop in the main chamber. This, in turn, limits the amount of compressed air that can be discharged (unloaded) through the unloading valve 104.

[0066] Specifically, at a given compressed air flow rate, the unloading valve cannot reliably discharge compressed air, leading to increased pressure in the compressed air supply system (including the air tank and / or braking system). For example, the higher the pressure and air flow rate, the greater the amount of air that is pumped into the vehicle's air tank instead of being discharged into the atmosphere.

[0067] The unloading spring force acting on piston 106 (in) Figure 2 (Indicated by two gray arrows) Keep the unloading valve 104 closed.

[0068] However, the difference in surface area between the two sealing rings 146 and 148 arranged on the piston at the pressure application location causes an imbalance in force distribution.

[0069] Unbalanced forces ( Figure 2 The dotted-line arrow in the image causes the piston to move in the open state mode.

[0070] When the force applied by compressed air and control pressure is greater than the spring force of the (first) spring 108, the piston moves and the unloading valve is in the open state mode.

[0071] Figure 3 An unloading valve assembly 102 according to the invention is shown for a compressed air supply system 100, such as a compressed air supply system for a vehicle, in which the safety valve is not activated, i.e., in the closed state. Reference numerals are used for the unloading valve 104 of the invention and as shown in the figure. Figure 1 and 2Common components / features of known unloading valves are shown.

[0072] The unloading valve assembly 102 includes an unloading valve 104 and a safety valve 130.

[0073] The unloading valve 104 includes a piston 106 and a first spring 108. The piston is configured (along the central axis 112) to move against the biasing force of the first spring 108 between a seated position and a first unseatped position on the first valve seat 110.

[0074] The safety valve 130 includes a valve stem 132 and a second spring 134 that acts on the valve stem 132 to thereby keep the safety valve in the closed state.

[0075] Specifically, the unloading spring force (indicated by two gray arrows) is configured to hold piston 106 in the first seated position 110, i.e., the closed state.

[0076] The spring force of the second spring 134 is configured to hold the (integrated) valve stem in the second seat position 140, i.e., in the closed state.

[0077] The unloading spring force is calibrated to keep the unloading valve of the air compressor of the compressed air supply system 100 (i.e., in loading mode) closed under normal operation. For example, the spring force is between 140-170 N, preferably between 150-160 N.

[0078] Specifically, the piston 106 also includes a piston passage 120 communicating with a piston chamber 128 defined within the piston 106.

[0079] Piston 106 also includes piston head 122, piston body 124 and piston pin 126.

[0080] Specifically, the piston pin 106 is detachably fixed to the piston body. For example, the piston pin is screwed onto the inner circumference of the piston body.

[0081] Compressed air is configured to be guided into the main chamber via inlet passage 114. In particular, the compressed air acting on the piston generates an unbalanced force acting on piston 106 (especially piston body).

[0082] In addition, a control pressure signal is applied to the piston 106 (particularly the piston head 122) through the control channel 118.

[0083] Specifically, the unloading valve 104 is configured to open (activate) when the combined force (net force) of all forces acting on piston 106 is large enough to exceed the first spring force 108. For example, when the spring force is in the range of 150 to 160 N and there is no pressure in inlet passage 114, approximately 6 bar is required in passage 118 to activate the unloading valve. Any pressure in passage 114 contributes to the opening of the piston, thereby reducing the pressure required in passage 118.

[0084] Figure 4 An unloading valve assembly 102 for a compressed air supply system 100 in an activated state according to the present invention is shown.

[0085] When the unloading valve assembly is in the active state, the compressed air acting on the unloading valve assembly (within the inlet channel 114) exceeds a first predetermined condition.

[0086] For example, safety valve 130 is configured to be activated when the pressure of compressed air in inlet passage 114 exceeds a given / predetermined pressure level, so as to direct the compressed air received via inlet passage 114 to discharge passage 116.

[0087] As an adjustable safety valve, this can be any value between 11 and 17 bar in the current design. This range is achieved through two variations of the compression spring (part 134). A weaker spring, for example, has an adjustable range of 11–15 bar, and a stronger spring, for example, has an adjustable range of 15–17 bar. By using springs of other strengths, this range can be extended and / or varied in either direction.

[0088] Specifically, the pressure level can vary between 11 and 17 bar, and the safety valve setting (configuration) can be adjusted as needed. This adjustment can be achieved, for example, by two types of compression springs 134. One is a weaker spring with an adjustable range of approximately 11 to 15 bar, and the other is a stronger spring with an adjustable range of approximately 15 to 17 bar. By utilizing the new springs, this range can also be extended in either direction.

[0089] During normal operation of the compressor (in loading and unloading modes), the internal safety valve is not activated. That is, the spring force of the second spring 134 is calibrated in such a way that the pressure during normal operation (use) cannot move the valve stem 132.

[0090] For example, valve stem 132 is configured to resist movement of second spring 134 when the pressure of compressed air guided into the piston chamber and acting on valve stem exceeds a first predetermined level or condition.

[0091] Specifically, when the unloading valve 104 remains closed and the pressure in the inlet passage 114 increases, the pressure exceeds a first predetermined level.

[0092] Alternatively or additionally, the pressure in inlet passage 114 may increase due to the absence of control pressure in control passage 118, which in turn keeps the unloading valve closed.

[0093] Safety valve 130 is disposed in piston chamber 128 within piston 106 of unloading valve 104.

[0094] Specifically, the piston passage is configured to guide compressed air received from the inlet passage 114 into the piston chamber 116.

[0095] The piston chamber 128 includes an outlet passage 140. The outlet passage 140 is configured to communicate with the discharge passage 116.

[0096] The stem valve 132 includes a head portion 142. In particular, the head portion is configured to prevent compressed air from entering the piston chamber.

[0097] The head portion 142 includes a recess for retaining the first sealing element 144.

[0098] Specifically, in the closed state, the safety valve 130 is configured to prevent compressed air from entering the piston chamber 128.

[0099] The valve stem 132 is configured to move along the central axis 112 and against the biasing force of the second spring 134 between a seated position and a second unseatped position on the second valve seat 136.

[0100] Specifically, the safety valve is not activated (i.e. closed) and is located at the second seat valve 136 formed on the piston pin 126.

[0101] The stem valve is configured to move by the force generated by compressed air (received from inlet passage 114) guided into piston chamber 128 via piston passage 120.

[0102] Figure 5 A partial view of the unloading valve assembly 120 according to the present invention is shown, with the safety valve in a first open state mode.

[0103] The safety valve includes a buffer chamber 138 for maintaining compressed air in a first open state mode within the piston chamber 128. Specifically, the compressed air provides a first predetermined condition.

[0104] For example, a safety valve is configured to acquire a first open state mode when the compressed air has a given pressure level, such as 11-17 bar.

[0105] In the first open state mode, the valve stem 132 is configured to move, thereby promoting the accumulation of compressed air in the buffer chamber 138.

[0106] Specifically, the buffer chamber 138 is defined between the head portion 142 of the rod valve and the inner periphery of the piston chamber 128.

[0107] For example, a buffer chamber 138 is configured to be formed (provided) by a gap between the head portion of the rod valve and the inner periphery of the piston chamber. This gap is designed and configured to allow compressed air that meets a first predetermined condition to enter the buffer chamber. In this way, the gas acts as a nozzle to promote the flow of compressed air in a controlled manner.

[0108] The buffer chamber is defined by the first hole of the piston body 124 and the head portion of the rod valve 132.

[0109] Figure 6 A partial view of the unloading valve assembly 102 according to the present invention is shown, in which the safety valve is in a second open state mode.

[0110] Safety valve 130 is configured to acquire a second open state mode when the compressed air in buffer chamber 138 exceeds a first predetermined condition. Specifically, the compressed air provides the second predetermined condition.

[0111] For example, safety valve 130 is configured to acquire a second open state mode when the pressure in the buffer chamber exceeds a second pressure level.

[0112] In the second open state mode, valve stem 132 is configured to move, thereby guiding compressed air in buffer chamber 138 through outlet passage 140 to discharge passage 116.

[0113] In the first open state mode, the rod valve is configured to define a buffer chamber 138 between the head portion 142 of the rod valve and the inner periphery of the piston chamber 128 for holding compressed air therein.

[0114] Specifically, when the safety valve 130 is activated and the valve stem 132 moves to the second open state mode, the outlet passage 140 (located in the piston pin) is in fluid communication with the discharge passage 116.

[0115] Figure 7 A schematic partial view of piston 106 and sealing elements 146, 148 is shown.

[0116] The sealing element includes a first sealing ring 146, for example, having a circular cross-section, and a second sealing ring 148. A close-up of the second sealing ring 148 is shown on the right side of the figure.

[0117] The second sealing ring 148 advantageously has a square cross-section.

[0118] For example, the unloading assembly 102 also includes a retaining element 150, such as a metal disc (stainless steel), configured to hold and secure the second sealing ring in place. The disc is configured to bend over (bend) the second sealing ring to improve retention of the second sealing ring 148.

[0119] Specifically, on piston 106, the two sealing edges of the second sealing element 148 are held in place, one edge by a shoulder on the piston and the other by a metal disc. This further improves the effectiveness of the seal. The more robust fixation (on both sides of the square ring) ensures the seal is very securely held and can withstand the effects of expansion.

[0120] List of reference numerals 100 Compressed Air Supply System 102 Unloading Valve Assembly 104 Unloading Valve 106 Pistons 108 First Spring 110 First valve seat 112 Central Axis 114 Entrance Passage 116 Emission Channel 118 Control Channel 120 Piston Channel 122 Piston Head 124 Piston Body 126 Piston Pin 128 Piston Chamber 130 safety valve 132 Valve stem 134 Second Spring 136 Second Valve Seat 138 Buffer Chamber 140 Exit Channel 142 Head section 144 Sealing element 146 First sealing ring 148 Second sealing ring 150 Fixing Components

Claims

1. An unloading valve assembly (102) for a compressed air supply system (100), particularly for a compressed air supply system for a vehicle. The unloading valve assembly (102) includes an unloading valve (104). in, The unloading valve (104) includes a piston (106) and a first spring (108), and The piston is configured to move between a seated position and a first unseatped position on the first valve seat (110) against the biasing force of the first spring (108). The unloading valve assembly (102) also includes a safety valve (130). The safety valve (130) is configured to be activated when a first predetermined condition in the inlet channel (114) is exceeded by compressed air, so as to direct the compressed air received via the inlet channel (114) to the discharge channel (116).

2. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 1. Its features are, The safety valve (130) is arranged in a piston chamber (128) within the piston (106) of the unloading valve (104).

3. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 2. Its features are, The piston chamber (128) includes an outlet passage (140) configured to communicate with the discharge passage (116).

4. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 2 or 3. Its features are, The piston (106) includes a piston passage (120) configured to direct the compressed air into the piston chamber (116).

5. An unloading valve assembly (102) for a compressed air supply system (100) according to any one of the preceding claims. Its features are, The safety valve (130) includes a valve stem (132) and a second spring (134) acting on the valve stem (132) to keep the safety valve in a closed state. In the closed state, the safety valve (130) is configured to prevent the compressed air from entering the piston chamber (128).

6. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 5. Its features are, The valve stem (132) is configured to move along the central axis (112) and against the biasing force of the second spring (134) between a seated position and a non-seated position on the second valve seat (136). Preferably, the stem valve (132) is configured to move by compressed air guided into the piston chamber (128) via the piston passage (120).

7. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 5 or 6. Its features are, The valve stem (132) includes a head portion (142), preferably including a recess for receiving a sealing element (144).

8. The unloading valve assembly (102) for a compressed air supply system (100) according to any one of claims 5 to 7. Its features are, The safety valve includes a buffer chamber (138) for maintaining compressed air in a first open state mode within the piston chamber (128), preferably, the compressed air provides the first predetermined condition.

9. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 8. Its features are, In the first open state mode, the valve stem (132) is configured to move within the piston chamber (128), thereby allowing compressed air to enter and accumulate in the buffer chamber (138), specifically, the buffer chamber including a gap disposed between the outer periphery of the head portion (142), particularly the outer periphery of the head portion (142), and the inner periphery of the piston chamber (128).

10. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 8 or 9. Its features are, The safety valve (130) is configured to obtain a second open state mode when the compressed air in the buffer chamber (138) exceeds the first predetermined condition, and in particular, provides the second predetermined condition.

11. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 9. Its features are, In the second open state mode, the valve stem (132) is configured to move to guide the compressed air through the outlet passage (140) into the discharge passage (116).

12. An unloading valve assembly (102) for a compressed air system according to any one of the preceding claims. Its features are, The piston (106) further includes a piston head (122), a piston body (124), and a piston pin (126). Preferably, the piston pin is detachably fixed to the piston body.

13. The unloading valve assembly (102) for a compressed air system according to claim 12. Its features are, The piston body (124) includes a first hole and a second hole, and the piston pin includes a third hole. Preferably, the first hole, the second hole and the third hole together define a piston chamber (128) for receiving the safety valve (130).

14. The unloading valve assembly (102) for a compressed air system according to claim 12 or 13. Its features are, The piston head (122) includes a groove on its outer periphery for receiving the first sealing ring (146).

15. The unloading valve assembly (102) for a compressed air supply system (100) according to claim 9, 10 or 11. Its features are, The piston body (124) includes a recess on its outer periphery for receiving a second sealing ring (148).

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