MXPA06008287A - Actuator for a brake system and method of making a brake actuator - Google Patents

Abstract

In an actuator for a brake system or a method for making a brake actuator, an attachment mechanism for attaching a diaphragm to a piston includes a plurality of protrusions on one of the piston and diaphragm and a plurality of cavities on the other of the piston and diaphragm, each protrusion being insertable into a corresponding cavity to attach the diaphragm to thepiston. Alternatively, a retaining ring is provided that need not be precisely made and yet can attach the diaphragm to the piston securely and sealingly.

Description

ACTUATOR FOR A BRAKE SYSTEM AND METHOD FOR THE PREPARATION OF A BRAKE ACTUATOR FIELD OF THE INVENTION The present invention relates to an actuator for a brake system and a method for manufacturing a brake system.

BACKGROUND OF THE INVENTION Vehicles, in particular commercial vehicles, for example, trucks and buses, usually employ a preventive braking system. This type of preventive braking systems usually include an air operated actuator to apply the brake itself, such as disc or drum brakes. An example of an air operated actuator is a spring-type brake actuator, wherein the actuator includes a spring, which is compressed by the compressed air, and the compressed spring applies the brake when the compressed air is released for parking situations or emergency. The spring brake actuator includes a housing (or cylinder), a spring pressure plate (or piston) movably located in the housing, and a diaphragm that seals in a sealable manner to the housing and pressure plate of the housing. spring (or the parking piston). Consequently, the diaphragm functions as a seal between the housing and the spring pressure plate. The housing, the pressure plate and the diaphragm define an air chamber to receive the compressed air. The compressed air inside the air chamber is pushed against the spring pressure plate to compress the spring. As a rule, the diaphragm adheres to, and seals against, the spring pressure plate with a retaining ring, which is mounted on the diaphragm and presses it against the pressure plate. The retaining ring must be manufactured precisely. If the ring is too small, it may be difficult to mount the ring on the diaphragm, or the ring may damage the diaphragm. If it is too large, the ring may not press the diaphragm against the pressure plate enough for secure attachment and sealing. As a result, the retaining ring is relatively expensive.

SUMMARY OF THE. INVENTION The present invention provides an actuator for a brake system and a method for the manufacture of a brake actuator, wherein the retaining ring is not required to fix the diaphragm to the piston (or the spring pressure plate) in a manner Safe and sealable. Alternatively, the present invention provides a retaining ring that does not need to be manufactured accurately and yet can secure the diaphragm to the piston in a secure and sealable manner. Accordingly, the present invention overcomes the disadvantages associated with the prior art. In accordance with one aspect of the present invention, an actuator for a brake unit includes a housing, a piston movably located in the housing, an elastic diaphragm for providing a seal between the housing and the piston, and a fixing mechanism. which is designed to fix the diaphragm to the piston. The locking mechanism can include a plurality of projections on one of either the piston and the diaphragm, and a plurality of cavities on the other of either the piston and the diaphragm, and each projection can be inserted into a corresponding notch to ensure the diaphragm to the piston. Each projection preferably includes a lower portion and an upper portion that is larger than the lower portion, and each notch preferably includes an upper portion and a lower portion that is larger than the upper portion. (As used in this description, the word "larger" means larger in size, such as diameter, length, width, thickness or volume). When each notch is inserted into the corresponding sample, the lower portion of the protrusion can be coupled with the upper portion of the corresponding notch, and the upper portion of the protrusion can be coupled with the lower portion of the corresponding notch. This arrangement provides a more secure fixation. In another preferred modality, the diaphragm includes a plurality of elastic tubular members, each of which can be mounted on a projection on the piston. For each tubular member and for the corresponding projection, the internal space of the tubular member may be smaller than the projection when the tubular member is not mounted on the projection. When the tubular member is mounted on the projection, the elasticity of the tubular member allows it to expand and securely attach to the projection. In accordance with another aspect of the present invention, an actuator for a brake unit includes a housing; a piston located movably in the housing; and an elastic diaphragm to provide a seal between the housing and the piston. The piston includes a plurality of projections or a plurality of cavities, and the diaphragm is integrally molded in the projections or in the cavities to fix the diaphragm to the piston. In a preferred embodiment, the piston cavities are through holes, and the diaphragm is integrally molded in the through holes. According to yet another aspect of the present invention, a method for manufacturing a brake actuator includes the action of fixing the elastic diaphragm of the actuator to the actuator piston by inserting each of a plurality of projections into one of either the protrusion of the piston and the diaphragm in a corresponding one of a plurality of cavities in the other of either the piston and the diaphragm. In a preferred embodiment, the method includes the actions of making each projection with a lower portion and an upper portion that is larger than the lower portion, and fabricating each notch with an upper portion and a lower portion that is larger than the portion top of the notch. When each protrusion is inserted into the corresponding notch, the lower portion of the protrusion engages with the upper portion of the corresponding notch, and the upper portion of the protrusion engages the lower portion of the corresponding notch. In another preferred embodiment, the diaphragm is provided with a plurality of elastic tubular members. For each tubular member and for the corresponding projection, the internal space of the tubular member is preferably smaller than the projection when the tubular member is not mounted on the projection. As a result, when the tubular member is mounted on the projection, the elasticity of the tubular member allows it to expand and securely attach to the projection. According to yet another aspect of the present invention, a method for manufacturing a brake actuator includes the actions of providing the piston with a plurality of projections or with a plurality of cavities, and integrally molding the diaphragm in the projections or in the projections. the piston cavities to fix the diaphragm to the piston. In the embodiments described above, the diaphragm of the brake actuator is fixed to the brake actuator piston without the use of a retaining ring. As a result, the costs associated with manufacturing, transporting and storing the retaining ring are eliminated. According to a further aspect of the present invention, an actuator for a brake unit includes: a housing; a piston located movably in the housing; an elastic diaphragm to provide a seal between the housing and the piston; and a retaining ring to fix the diaphragm to the piston. The retaining ring has a U-shaped cross section with two legs, and the two legs of the retaining ring press the piston and the diaphragm together to secure the piston and the diaphragm to each other. The U-shaped configuration can be achieved by deforming the ring around the piston and the diaphragm. According to still another aspect of the present invention, a method for the manufacture of a brake actuator includes the action of employing a retaining ring having a U-shaped cross section with two legs for fixing the piston and the diaphragm between yes using the two legs of the retaining ring to press the piston and the diaphragm together. In these two modes, although a retaining ring is used, it is not necessary to accurately manufacture the ring. It is only necessary that the legs of the ring be sufficiently long as well as separate to mold the portions of the piston and diaphragm that are pressed together. Then, the legs of the ring can be deformed to fix the diaphragm to the piston. According to another aspect of the present invention, an actuator for a brake unit includes: a housing; a piston located movably in the housing; an elastic diaphragm to provide a seal between the housing and the piston; and a sealing mechanism that provides a seal between the housing and the piston. The sealing mechanism includes a rib-shaped portion of the diaphragm, the rib of which is pressed against an area of the piston to provide the seal between the diaphragm and the piston. When the diaphragm is not fixed to the piston, the rib is preferably smaller than the area of the piston, against which the rib is pressed. When the diaphragm is fixed to the piston, the rib extends to the size of the piston area, which causes the rib to be pressed against the piston area. The rib portion of the diaphragm may include a plurality of ribs configured in a parallel fashion. In a preferred embodiment, the housing, the pressure plate and the diaphragm define an air chamber for receiving the compressed air. The diaphragm includes a first side facing the air chamber and a second side in which the rib-shaped portion is located. When the air chamber is filled with compressed air, the latter presses the rib-shaped portion of the diaphragm against the piston, such as the outer periphery of the piston, to intensify the seal between the diaphragm and the piston. According to another aspect of the present invention, a method for manufacturing includes the steps of providing the diaphragm with a rib-shaped portion; pressing the rib against an area of the piston to provide a seal between the diaphragm and the piston; making the rib smaller than the area of the piston, against which the rib is pressed, when the diaphragm is not fixed to the piston; and fixing the diaphragm to the piston, in such a way that the rib of the sealing mechanism is extended to the size of the piston area, which causes the rib to be pressed against the piston area. In the above embodiments with sealing ribs, it is not necessary to accurately construct a retaining ring to seal the diaphragm against the piston. Instead, the elasticity of the diaphragm is used to press the ribs against the piston in order to provide a seal between the diaphragm and the piston. According to another aspect of the present invention, an actuator for a brake system includes: a housing; a piston located movably in the housing; and an elastic diaphragm to provide a seal between the housing and the piston. The housing has a base and a hood connected to the base, and the diaphragm includes a raised edge that is compressed between the base and the hood of the housing to fix the diaphragm to the housing. The raised edge of the diaphragm has a rib that is compressed against a slope of the base to provide a secure seal. Preferably, the hood is connected to the base by deforming the hood around a projection formed on the outer periphery of the base. Other objects, advantages and novel aspects of the present invention will be apparent from the following detailed description of the invention, when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial cross-sectional view of an actuator for a brake system according to the present invention.

Figure 2 is an exploded view of a portion of the actuator of Figure 1. Figure 3 shows a projection and a notch of a locking mechanism employed in Figures 1 and 2. Figure 4 is a cross-sectional view of another fixing mechanism according to the present invention. Figure 5 is a cross-sectional view of an additional actuator for a brake system according to the present invention. Figure 6 is a detailed cross-sectional view of a portion of the actuator of Figure 5 showing a retaining ring. Figure 7 is a detailed cross-sectional view of the actuator of Figure 1 showing the sealing ribs, which are located at the ends of the diaphragm, respectively.

DESCRIPTION OF THE PREFERRED MODALITIES Figures 1 and 2 show portions of an air operated (pneumatic) actuator for a brake system. The actuator (10) includes: a housing (12); a piston (14) movably located in the housing (12); and an elastic diaphragm (16) that seals the opening between the housing (12) and the piston (14).

In this embodiment, a portion of the casing (12) is not defined solely by the cylindrical outer wall (18), but also has a cylindrical internal wall (20), which occupies a portion of the interior space of the casing. The inner wall (20) does not interfere with the movement of the piston (14), since the piston (14) is hollow and the internal wall (20) can extend in the piston (12). On the other hand, the outer circumferential wall (22) of the piston (14) can extend in the space between the external and internal walls (18), (20) of the housing (12). The external and internal walls (18), (20) of the housing (12), the piston (14) and the diaphragm (16) define an air chamber (24) for receiving compressed air, which can move the piston ( 14) with respect to the housing (12). However, in general terms, each of the housing and the piston of the present invention can have any suitable configuration. For example, the housing can be a simple hollow cylinder, and the piston can be a solid cylinder or a circular plate, movable in the axial direction inside the cylindrical and hollow housing. As shown in Figure 2, the actuator (10) includes a fixing mechanism to fix the diaphragm (16) to the piston (14). This fixing mechanism includes a plurality of projections (26) and a plurality of cavities (28), wherein each projection (26) is inserted, in a corresponding notch (28) to secure the diaphragm (16) to the piston (14) . The term "notch", as used in this description, includes a through hole. In this embodiment, the projections (26) are configured in the piston (14) and the cavities (28) are configured in the diaphragm (16), although the projections can be configured in the diaphragm and the cavities can be configured in the piston . In a preferred embodiment shown in Figure 3, each projection (26) of the fixation mechanism has a lower portion (26a) and an upper portion (26b) that is wider than the lower portion (26a), and each recess ( 28) (a through hole in this embodiment) includes an upper portion (28a) and a lower portion (28b) that is wider than the upper portion (28a) of the cavity (28). When the projection (26) is inserted into the cavity (28), the lower portion (26a) of the projection (26) engages with the upper portion (28a) of the cavity (28), and the upper portion (26b) of the projection (26) engages with the lower portion (28b) of the cavity (28). With this configuration, the projection (26) can be securely fixed within the cavity (28). According to another aspect of the present invention, the elastic diaphragm is integrally molded in the piston. Preferably, the portion of the piston that is fixed to the diaphragm is configured in such a way that the diaphragm can be securely molded therein. For example, the piston may have the projections (26) of Figure 2, and the diaphragm may be integrally molded into the projections (26). Alternatively, the piston may have the cavities (28), and the diaphragm may be molded integrally in the cavities (28). In some cases, the piston cavities may be through holes, and the diaphragm material may enter each through hole in both of its openings to ensure that the orifice fills with the diaphragm material. The integral molding process by itself is well known in the art and will not be discussed in more detail in this description. Figure 4 shows another embodiment of the fixation mechanism. In this embodiment, the fixing mechanism includes a plurality of protrusions (126) configured in the piston (112), which are similar to those shown in Figures 1 and 2, and a plurality of elastic tubular members (128) in the diaphragm (116). The protrusions (126) of the piston (112) can extend into the respective tubular members (128) of the diaphragm (116) to secure the diaphragm (116) to the piston (112). Analogous to the fixing mechanism shown in Figures 1 and 2, the internal space of each tubular member (128) can be considered as a cavity in the diaphragm (116), in which a projection (126) of the piston (112) can extend. Preferably, the internal space of the tubular member (128) is smaller than the projection (126) when the tubular member (128) is not mounted on the projection (126). When the tubular member (128) is mounted on the projection (126), the elasticity of the tubular member (128) allows it to expand and securely attach to the projection (126). The protrusions and cavities of the fixing mechanism can be configured in any suitable location on the piston and diaphragm. In the embodiment shown in Figures 1 and 2, for example, the projections (26) are configured at the end of the outer cylindrical wall (22) of the piston and extend in the axial direction. The cavities (28) are formed in the raised edge (30) of the diaphragm (16) and also extend in the axial direction. The raised edge (30) has sufficient volume to accommodate in the upper portion (28a). Alternatively, one or both of the projections and cavities may extend in any other direction, such as, for example, the radial direction. According to a further aspect of the present invention, a retaining ring is used to fix the diaphragm of a brake actuator with its piston. However, this retaining ring is different from the conventional retaining rings used in brake actuators in which it is necessary to manufacture them precisely. As shown in Figures 5 and 6, the retaining ring (232) has a U-shaped cross section with two legs (232a), (232b). The raised edge (230) of the diaphragm (216) and the end (234) of the piston (214) are secured together between the two legs (232a), (232b) to fix the diaphragm (216) to the piston (214). The diaphragm (216) has two ribs (236) which are pressed against a rim (238) extending in the radial direction of the piston (214) to seal the diaphragm (216) against the piston (214). The retaining ring (232) shown in Figures 5 and 6 does not need to be manufactured with precision, in contrast to the conventional retaining rings used in the brake actuators, does not use its size, as for example, the internal diameter or external, to fix the diaphragm to the piston. Instead, the ring (232) secures the diaphragm and piston together for fixation. If a conventional retaining ring is not manufactured with precision, it can compress the diaphragm against the piston either insufficiently for the purpose of correct fixing, or excessively damaging the diaphragm or making it at least difficult to assemble the ring. retention in the diaphragm. Although the above-mentioned locking mechanisms often produce a seal between the diaphragm and the piston, it may be desirable in certain cases to provide a separate sealing mechanism to ensure that the diaphragm is sealed securely against the piston. Figure 7 illustrates this type of sealing mechanism (40). In the actuator shown in Figure 7, the diaphragm (16) has a generally cylindrical configuration and, in the position shown in Figure 7, is configured concentrically with the piston (14). The diaphragm (16) includes two ribs (42) on its inner surface (44), each rib (42) forming a ring in general terms circular on the surface (44), although it may have one rib or more than two of them. The ribs (42) are pressed against the external surface (46) of the piston (14) by the elasticity of the diaphragm (16) and / or of the ribs (42). When the diaphragm (16) is not fixed to the piston (14), the ribs (42) or the area of the diaphragm (16), in which the ribs (42) are formed, are smaller or smaller, depending on the case, that the external diameter of the piston area, against which the ribs (42) are pressed. When the diaphragm (16) is fixed to the piston (14), as shown in Figure 7, the ribs (42) or the area of the diaphragm (16) is secured or secured in such a way that the elasticity of the ribs ( 42) or the diaphragm (16) press the ribs (42) against the outer surface (46) of the piston (14) to form a secure seal. Still further, when the air chamber (24) is filled with compressed air, the latter further presses the ribs (42) against the external surface (46) of the piston (14).

The diaphragm is also fixed to the actuator housing and sealed against it. In the embodiment shown in Figure 4, for example, the housing (112) includes a base (112a) and a hood (112b) connected to the base (112a). Preferably, the base 112a has a circular shoulder 113, and the hood 112b deforms around the circular shoulder 113 to form the connection between the base 112a and the hood 112b. The diaphragm (116) has a second raised edge (148) which is compressed between the base (112a) and the hood (112b) of the housing (112). As a result, the diaphragm (116) is fixed to the housing (112) and sealed against it. Preferably, as shown in Figure 7, the second raised edge (148) of the diaphragm (116) has the rib (150) which is compressed against the slope (152) of the base (112a) to provide a secure seal. The above disclosure has been described only to illustrate the invention and is not intended to limit it. Since those skilled in the art can devise modifications of the described embodiments incorporating the spirit and subject matter of the invention, the invention should be construed as including everything within the scope of the appended claims and equivalents thereof.

Claims (32)

1. CLAIMS 1. An actuator for a brake system comprising: a housing; a piston located movably in the housing; an elastic diaphragm to provide a seal between the housing and the piston; and a fixing mechanism configured to fix the diaphragm to the piston, wherein the fixing mechanism includes a plurality of projections either on the piston or on the diaphragm, and a plurality of cavities on the other of either the piston or the diaphragm , each protrusion can be inserted into a corresponding cavity to fix the diaphragm to the piston. The actuator according to claim 1, wherein each projection includes a lower portion and an upper portion that is larger than the lower portion, wherein each cavity includes an upper portion and a lower portion that is larger than the upper portion. of the cavity, and wherein when each protrusion is inserted into the corresponding cavity, the lower portion of the protrusion engages with the upper portion of the corresponding cavity, and the upper portion of the protrusion engages with the lower portion of the cavity. correspondent. The actuator according to claim 1, wherein the projections are on the piston, and the cavities are on the diaphragm, and where the diaphragm includes a plurality of elastic tubular members, each diaphragm cavity is defined by the internal space of the diaphragm. one of the tubular members. The actuator according to claim 3, wherein for each tubular member and for the corresponding projection, the internal space of the tubular member is smaller than the projection when the tubular member is not mounted on the projection, and where when the member tubular is mounted on the projection, the elasticity of the tubular member allows it to expand and securely attach to the projection. The actuator according to claim 1, further comprising a sealing mechanism for providing a seal between the diaphragm and the piston, wherein the sealing mechanism includes a U-shaped portion of the diaphragm, the rib is pressed against an area of the piston to provide the seal between the diaphragm and the piston, wherein when the diaphragm is not fixed to the piston, the rib of the sealing mechanism is smaller than the area of the piston, against which the rib is pressed, and where When the diaphragm is fixed to the piston, the rib of the sealing mechanism is lengthened to the size of the piston area, which causes the rib to be pressed against the piston area. 6. An actuator for a brake system comprising: a housing; a piston movably located in the housing, wherein the piston includes a plurality of projections or a plurality of cavities; and an elastic diaphragm for providing a seal between the housing and the piston, wherein the diaphragm is integrally molded in the projections or in the cavities of the piston to fix the diaphragm to the piston. The actuator according to claim 6, wherein the piston includes the plurality of cavities, and wherein the cavities are through-holes. The actuator according to claim 6, further comprising a sealing mechanism for providing a seal between the diaphragm and the piston, wherein the sealing mechanism includes a U-shaped portion of the diaphragm, the rib is pressed against an area of the piston to provide the seal between the diaphragm and the piston, wherein when the diaphragm is not fixed to the piston, the rib of the sealing mechanism is smaller than the area of the piston, against which the rib is pressed, and where When the diaphragm is fixed to the piston, the rib of the sealing mechanism is lengthened to the size of the piston area, which causes the rib to be pressed against the piston area. 9. An actuator for a brake system comprising: a housing; a piston located movably in the housing; an elastic diaphragm to provide a seal between the housing and the piston; and a fixing mechanism which is designed to fix the diaphragm to the piston, wherein the fixing mechanism includes a retaining ring having a U-shaped cross section with two legs, and wherein the two legs of the retaining ring press the piston and the diaphragm with each other to fix the piston and the diaphragm together. 10. An actuator for a brake system comprising: a housing; a piston located movably in the housing; an elastic diaphragm to provide a seal between the housing and the piston; and a sealing mechanism for providing a seal between the diaphragm and the piston, wherein the sealing mechanism includes a U-shaped portion of the diaphragm, the rib is pressed against an area of the piston to provide the seal between the diaphragm and the seal. piston, wherein when the diaphragm is not fixed to the piston, the rib of the sealing mechanism is smaller than the area of the piston, against which the rib is pressed, and where when the diaphragm is fixed to the piston, the rib of the piston Sealing mechanism is lengthened to the size of the piston area, which causes the rib to be pressed against the piston area. The actuator according to claim 10, wherein the U-shaped portion of the diaphragm includes a plurality of ribs configured in parallel. The actuator according to claim 10, wherein the housing, the pressure plate and the diaphragm define an air chamber for receiving the compressed air, wherein the diaphragm includes a first side facing the air chamber, and a second side on which the U-shaped portion is located, and where when the air chamber is filled with compressed air, the latter pushes the U-shaped portion of the diaphragm against the piston to intensify the seal between the diaphragm and the piston. 13. A method for manufacturing a brake actuator comprising a housing, a piston movably located in the housing and an elastic diaphragm to provide a seal between the housing and the piston; The method comprises the action of: fixing the elastic diaphragm to the piston by inserting each of a plurality of projections into one of either the projection of the piston or the diaphragm in a corresponding one of a plurality of cavities in the other of either the piston and the diaphragm. The method according to claim 13, further comprising the actions of: making each projection with a lower portion and an upper portion that is larger than the lower portion; and fabricating each cavity with an upper portion and a lower portion that is larger than the upper portion of the cavity, wherein when each projection is inserted into the corresponding cavity, the lower portion of the projection engages the upper portion of the cavity. corresponding cavity, and the upper portion of the projection engages the lower portion of the corresponding cavity. The method according to claim 13, wherein the plurality of the projections are in the piston and the plurality of the cavities are in the diaphragm, the method further comprising providing in the diaphragm a plurality of elastic tubular members, each diaphragm cavity it is defined by the internal space of one of the tubular members. The method according to claim 15, further comprising, for each tubular member and the corresponding projection, creating the internal space of the tubular member smaller than the projection when the tubular member is not mounted on the projection, so that when the The tubular member is mounted on the projection, the elasticity of the tubular member allows it to expand and securely attach to the projection. The method according to claim 13, further comprising the steps of: providing the diaphragm with a U-shaped portion; pressing the rib against an area of the piston to provide a seal between the diaphragm and the piston; making the rib smaller than the area of the piston, which contracts the rib, when the diaphragm is not fixed to the piston; and fixing the diaphragm to the piston so that the rib of the sealing mechanism is extended to the size of the piston area, which causes the rib to be pressed against the piston area. 18. A method for manufacturing a brake actuator comprising a housing, a piston movably located in the housing, and an elastic diaphragm for providing a seal between the housing and the piston, the method comprising the actions of: providing the piston with a plurality of projections or with a plurality of cavities; and integrally molding the diaphragm in the projections or in the cavities of the piston to fix the diaphragm to the piston. The method according to claim 18, wherein the piston includes the plurality of cavities, and wherein the cavities are through-holes. The method according to claim 18, further comprising the steps of: providing the diaphragm with a U-shaped portion; pressing the rib against an area of the piston to provide a seal between the diaphragm and the piston; making the rib smaller than the area of the piston, against which the rib is pressed, when the diaphragm is not fixed to the piston; and fixing the diaphragm to the piston in such a way that the rib of the sealing mechanism is lengthened to the size of the piston area, which causes the rib to be pressed against the piston area. 21. A method for manufacturing a brake actuator comprising a housing, a piston movably located in the housing and an elastic diaphragm to provide a seal between the housing and the piston; the method comprises: employing a retaining ring having a U-shaped cross section with two legs for securing the piston and the diaphragm to each other by pressing the piston and the diaphragm together with the two legs of the retaining ring. 22. A method for manufacturing a brake actuator comprising a housing, a piston movably located in the housing and an elastic diaphragm to provide a seal between the housing and the piston; the method comprises: providing the diaphragm with a U-shaped portion; pressing the rib against an area of the piston to provide a seal between the diaphragm and the piston; making the rib smaller than the area of the piston, against which the rib is pressed, when the diaphragm is not fixed to the piston; and fixing the diaphragm to the piston in such a way that the rib of the sealing mechanism is lengthened to the size of the piston area, which causes the rib to be pressed against the piston area. The method according to claim 22, wherein the U-shaped portion of the diaphragm includes a plurality of ribs configured in parallel. The method according to claim 22, wherein the housing, the pressure plate and the diaphragm define an air chamber for receiving compressed air, wherein the diaphragm includes a first side facing the air chamber and a second side facing the air chamber. which is the U-shaped portion, and where when the air chamber is filled with compressed air, the compressed air pushes the U-shaped portion of the diaphragm against the piston to intensify the seal between the diaphragm and the piston . 25. A piston / diaphragm unit for an actuator of a brake system; The unit comprises: a piston; an elastic diaphragm; and a fixing mechanism configured to fix the diaphragm to the piston, wherein the fixing mechanism includes a plurality of projections on one of either the piston and the diaphragm, and a plurality of cavities on the other of either the piston and the piston. diaphragm, each protrusion can be inserted into a corresponding cavity to fix the diaphragm to the piston. 26. The actuator according to claim 25, wherein the projections on the piston and the cavities are in the diaphragm, and wherein the diaphragm includes a plurality of elastic tubular members, each diaphragm cavity is defined by the internal space of the diaphragm. tubular members. The actuator according to claim 26, wherein for each tubular member and for the corresponding projection, the internal space of the tubular member is smaller than the projection when the tubular member is not mounted on the projection, and where when the member The tubular member is mounted on the projection, the elasticity of the tubular member allows it to expand and securely attach to the projection. 28. A piston / diaphragm unit for an actuator of a brake system; the unit comprises: a piston that includes a plurality of projections or a plurality of cavities; and an elastic diaphragm that is integrally molded in the projections or in the cavities of the piston to fix the diaphragm to the piston. 29. The actuator according to claim 28, wherein the piston includes the plurality of cavities, and wherein the cavities are through-holes. 30. A piston / diaphragm unit for an actuator of a brake system; The unit comprises: a piston; an elastic diaphragm; a sealing mechanism for providing a seal between the diaphragm and the piston, wherein the sealing mechanism includes a U-shaped portion of the diaphragm, the rib is pressed against an area of the piston to provide the seal between the diaphragm and the piston , wherein when the diaphragm is not fixed to the piston, the rib of the sealing mechanism is smaller than the area of the piston, against which the rib is pressed, and where when the diaphragm is fixed to the piston, the rib of the mechanism The seal is extended to the size of the piston area, which causes the rib to be pressed against the piston area. 31. An actuator for a brake system comprising: a housing including a base and a hood connected to the base; a piston located movably in the housing; and an elastic diaphragm for providing a seal between the casing and the piston, wherein the diaphragm includes a raised projection that is compressed between the base and the hood of the casing to fix the diaphragm to the casing, and wherein the raised projection of the casing The diaphragm has a rib that is compressed against a base slope to provide a secure seal. 32. The actuator according to claim 31, wherein the hood is connected to the base by deforming the hood around a projection formed on the outer periphery of the base.