Piston cover for a brake actuator and brake actuator comprising a respective piston cover

Abstract

A piston boot for a brake actuator and a brake actuator comprising a respective piston boot are provided. The piston boot (50) comprises a first end (52), a second end (54) and a compressible middle section (56), wherein the piston boot (50) has the form of a hollow, generally cylindrical body. The second end (54) comprises an opening (64) and a groove (60) at the outer circumference of the second end (54) for mounting the second end (54) at a housing cover of a brake actuator, wherein the second end (54) further comprises a lip (62) extending into the opening (64) of the second end (54).

Description

Technical Field

[0001] The present invention relates to a piston cover for a brake actuator and a brake actuator including a corresponding piston cover. Background Technology

[0002] Brake actuators are widely used in compressed air braking systems in vehicles, such as commercial vehicles like heavy-duty trucks, buses, and trailers. Such brake actuators operate using compressed air supplied by a compressed air supply container, which is filled by a compressor. The brake actuator includes a housing containing a pressure chamber and a diaphragm. During a braking action initiated by the vehicle's driver, as the pressure chamber is filled with compressed air, a push rod is displaced via the diaphragm to engage the vehicle's disc or drum brakes.

[0003] Figure 1 The image depicts a disc brake 2 according to the prior art, together with a spring brake actuator 4 of an air braking system. The disc brake 2 includes a brake anchor plate 6 as a basic component, a caliper 8 with a clamping unit, and brake pads 10 arranged axially movably on the brake anchor plate 6. The caliper 8 is arranged on a guide pin on the brake anchor plate 6, which allows axial movement of the caliper 8 relative to the brake anchor plate 6 during braking. The spring brake actuator 4 is mounted on the disc brake 2 and operates using compressed air.

[0004] Figure 2 A cross-sectional view of the main parts of the disc brake 2 and the spring brake actuator 4 is shown when the spring brake actuator 4 is in the released state. The spring brake actuator 4 includes a push rod 12, which provides axial movement of the yoke of the caliper 8 by means of the lever 14 of the disc brake 2, by means of this axial movement, the brake pad 10 is pushed against the brake rotor (in... Figure 1 and Figure 2 (Not shown in the image) To generate friction, the brake rotor is mounted on the vehicle's axle. Lever 14 is connected to the push rod 12 of the spring brake actuator 4. During braking, the diaphragm of the spring brake actuator 4 displaces the push rod 12 along the direction of lever 14. The spring brake actuator 4 further includes a service brake spring 16 disposed in a service spring chamber 18. When the spring brake actuator 4 is released, the service brake spring 16 pushes back the diaphragm and push rod 12. Furthermore, the spring brake actuator 4 includes a bellows-shaped piston cover 20 that encloses the middle portion of the push rod 12 to seal the interior of the disc brake 2 and isolate it from the external environment.

[0005] The piston cover 20 is typically made of rubber and includes a first end 22, a second end 24, and an intermediate section 26. The piston cover 20 has a hollow, generally cylindrical body shape, such as... Figure 3 Depicted in a side view. The intermediate section 26 includes a set of folding elements 28, and the intermediate section 26 is compressible like a bellows. Ends 22 and 24 each have the form of a ring. The first end 22 includes a groove 30 at its outer periphery in which a clamping element 32, such as a metal ring (see...) is mounted. Figure 2 ( ), so that the first end 22 is fixed to the push rod 12, and the second end 24 includes a groove 34 on its outer periphery, by means of which the second end 24 is fixed to the housing cover 36 of the spring brake actuator 4, see Figure 2 During braking, the clamping element 32 prevents the first end 22 from moving on the push rod 12. Ends 22 and 24 are tightly fitted so that the piston cover 20 is compressed during the braking action of the spring brake actuator 2 and extends when the spring brake actuator 4 releases the disc brake 2.

[0006] exist Figure 4 The image shows a cross-section of the second end 24 and a portion of the intermediate section 26 of the piston cover 20. The second end 24 includes an opening 38 having a diameter 40 larger than the outer diameter 42 of the intermediate section 26.

[0007] In some applications, when a compact size of the spring brake actuator 4 is preferred, such as... Figure 5 As shown, when the spring brake actuator 4 is fully applied, a portion 44 of the intermediate section 26 of the piston cover 20 partially enters the caliper 8. In this situation, a portion 44' of the intermediate section 26 contacts the sharp machined edge 46 of the caliper 8. Therefore, a large amount of abrupt braking action may damage the intermediate section 26 of the piston cover 20, resulting in the loss of the sealing function of the piston cover 20.

[0008] DE 4424721 A1 discloses a spring brake actuator including a piston cover. DE 10 2012 006090 A1 discloses a brake chamber including a piston cover. Summary of the Invention

[0009] One object of the present invention is to provide a piston cover and a brake actuator including a corresponding piston cover, both of which have improved reliability and lifespan.

[0010] The solution of the present invention is as follows.

[0011] The present invention provides a piston cover comprising a first end, a second end, and a compressible intermediate section, wherein the piston cover has the form of a hollow, cylindrical body. The second end includes an opening and a groove at the outer periphery of the second end for mounting the second end to a housing cover of a brake actuator, wherein the second end further includes a lip extending into the opening of the second end.

[0012] In a preferred embodiment, when the service brake is applied, the lip is sized to separate the caliper of the disc brake from the middle section of the piston cover, wherein the service brake spring of the brake actuator is fully compressed during the braking action.

[0013] In another preferred embodiment, during braking action when the service brake spring is fully compressed, the lip is sized to prevent contact between the intermediate section and the caliper blade.

[0014] In another preferred embodiment, during braking action when the service brake spring is fully compressed, the end of the lip covers the cutting edge of the caliper.

[0015] In another preferred embodiment, the lip includes a central hole having a diameter smaller than the outer diameter of the intermediate section.

[0016] In another preferred embodiment, the central hole of the lip edge has a circular shape, an elliptical shape, or a polygonal shape.

[0017] In another preferred embodiment, the lip margin includes an incision that divides the lip margin into two or more segments.

[0018] In another preferred embodiment, the lip is made of the same material as the piston cover, such as rubber.

[0019] In another preferred embodiment, the lip edge includes a reinforcing layer, such as a fabric layer molded within the lip edge.

[0020] Because the lip prevents contact between the intermediate section and the caliper blade during braking when the service brake spring is fully compressed, the reliability and lifespan of the piston cover are improved.

[0021] In another aspect of the invention, a brake actuator is provided, which includes a piston cover as described above. In a preferred embodiment, the brake actuator includes a push rod having a section surrounded by the piston cover.

[0022] Braking actuators, especially brake chamber or spring brake actuators. Attached Figure Description

[0023] Preferred embodiments of this disclosure are explained in more detail below by way of example with reference to the schematic diagrams, which illustrate: Figure 1 Disc brakes and spring brake actuators in existing air braking systems; Figure 2 : Figure 1 Cross-sectional view of the main parts of the disc brake and spring brake actuator; Figure 3 : Figure 1 A side view of the piston cover of the spring brake actuator in the middle; Figure 4 : Figure 3 A cross-section of a portion of the piston cover; Figure 5 When the spring brake actuator is fully applied, Figure 1 A detailed cross-section of the disc brake and spring brake actuator in the image; Figure 6 The first preferred embodiment of the piston cover according to the present invention; Figure 7 : Figure 6 The cross-section of the piston cover; Figure 8 When the brake actuator is fully applied, the disc brake and including Figure 6 A detailed cross-section of the brake actuator in the piston cover; Figure 9 The second preferred embodiment of the piston cover according to the present invention; Figure 10 The third preferred embodiment of the piston cover according to the present invention; Figure 11 The fourth preferred embodiment of the piston cover according to the present invention; and Figure 12 This is part of a fifth preferred embodiment of the piston cover according to the present invention. Detailed Implementation

[0024] This specification illustrates the principles of this disclosure. Therefore, it will be appreciated that those skilled in the art will be able to design various arrangements that, while not expressly described or shown herein, embody the principles of this disclosure and are included within its scope.

[0025] All examples and conditional language listed herein are intended for guiding purposes to help the reader understand the principles of this disclosure and the concepts contributed by the inventors to advance the art, and should be construed as not being limited to such specifically listed examples and conditions. Furthermore, all statements and specific examples of the principles, forms, and embodiments of this disclosure listed herein are intended to include their structural and functional equivalents.

[0026] Figure 6 A piston cover 50 is depicted, comprising a first end 52, a second end 54, and an intermediate section 56, wherein the piston cover 50 has a hollow, generally cylindrical body. The intermediate section 56 includes a set of folding elements 58, and the intermediate section 56 is compressible like a bellows. The piston cover 50 is made of, for example, a rubber material, or at least the intermediate section 56 is made of a rubber material, and the piston cover 50 is specifically designed for disc brakes.

[0027] As relative to Figure 2 As described, the first end 52 is designed to provide a tight fit at the push rod of the brake actuator, so that the first end 52 slides on the push rod during braking action of the brake actuator. The second end 54 includes a groove 60 on its outer periphery, by means of which the second end 54 can be mounted on the housing cover of the brake actuator. Ends 52 and 54 are designed such that the interior of the disc brake, especially during operation of the brake actuator, is sealed and isolated from the external environment.

[0028] The second end portion 54 includes a lip 62 that extends into an opening 64 of the second end portion 54. The lip 62 is made, for example, of the same material as the second end portion 54.

[0029] Figure 7 The piston cover 50 is depicted in cross-section. A first end 52 includes an opening 66, and a second end 54 includes an opening 64. The first end 52 includes a groove 68 at its outer periphery to secure the first end 52 to the push rod of the brake actuator. The intermediate section 56 in this embodiment includes three compressible folding elements 58. The first end 52 has the form of an annular element having an inner diameter 70 corresponding to the diameter of the brake actuator push rod. The second end 54 also has the form of an annular element having an inner diameter 72 larger than the outer diameter 74 of the intermediate section 56. The lip 62 includes a central hole 80 having a diameter 82 smaller than the outer diameter 74 of the intermediate section 56.

[0030] Figure 8The disc brake 90 and brake actuator 92, including piston cover 50, are depicted in cross-section, showing the condition when the brake actuator 92 is fully applied. A first end 52 of the piston cover 50 is fixed to the push rod 94 of the brake actuator 92, and a second end 54 of the piston cover 50 is fixed to the housing cover 96 of the brake actuator 92. In this configuration, the intermediate section 56 of the piston cover 50 is fully compressed. Due to the compact size of the disc brake 90 and brake actuator 92, the push rod 94 and a portion of the piston cover 50 partially enter the caliper 98 of the disc brake 90. In this configuration, the second end 54 rests against the caliper 98, and the sharp edge 100 of the caliper 98 contacts the lip 62. The end 102 of the lip 62 specifically surrounds the edge 100, thus preventing any contact between the edge 100 and the intermediate section 56 during full application of the brake actuator 92. Therefore, the middle section 56 of the piston cover 50 will not be damaged by the braking action of the brake actuator 92.

[0031] In a preferred embodiment, the central hole 80 of the lip 62 has a circular shape. Figure 9 A second preferred embodiment of the piston cover 110 is depicted, the piston cover 110 including a lip 112 having a central hole 114 having an elliptical shape. Figure 10 A third preferred embodiment of the piston cover 120 is depicted, the piston cover 120 including a lip 122 having a central hole 124 having a polygonal shape.

[0032] Figure 11 A fourth preferred embodiment of the piston cover 130 is depicted, the piston cover 130 including a lip 132 with a central hole 134, wherein the lip 132 includes a plurality of cuts, in this embodiment four cuts 136, which divide the lip into a plurality of segments 138, which allow for more free movement of the lip 132.

[0033] Figure 12 A portion of a fifth preferred embodiment of a piston cover 140 is depicted in cross-section. The piston cover 140 includes a lip 142, which includes a reinforcement 144. The reinforcement 144 is, for example, a layer of fabric molded within the lip 142.

[0034] Other embodiments may be used by those skilled in the art without departing from the scope of this disclosure.

[0035] List of reference numerals (part of the instruction manual): 2 disc brakes 4 Spring Brake Actuator 6 Brake Anchor Plate 8-caliper 10 brake pads 12 putters 14 levers 16 service brake springs 18 traveling spring chambers 20 Piston Cover The ends of piston covers 22 and 24 26 Piston Cover Middle Section 28 folding elements 30 Groove at the first end 22 32 clamping elements 34 The groove at the second end 24 36 housing cover 38 The opening at the second end 24 40 opening diameter 38 42 Intermediate section 26 outer diameter 44, 44' Intermediate Section 26 46 brake caliper 8 machined cutting edge 50 piston cover 52, 54 Piston cover 50 end 56 Piston Cover 50 Middle Section 58 Folding Components 60 The groove at the second end 54 62 Lip Edge 64 Opening at the second end 54 66 Opening at the first end 52 68 Groove at the first end 52 70 Inner diameter of the first end 52 72 Inner diameter of the second end 54 74 Intermediate Section 56 Outer Diameter 80 lip margin 62 center hole 82 center hole diameter 80 90 disc brake 92 Brake Actuator 94 brake actuator 92 push rod 96 brake actuator housing cover 98 disc brake with 90 caliper 100 caliper 96 blade 102 Lip edge 62 end 110 Piston Cover 112 piston cover, 110 lip edge 114 lip margin 112 center hole 120 piston cover 122 piston cover, 120 lip edge 124 lip margin 122 center hole 130 Piston Cover 132 piston cover, 130 lip edge 134 lip margin 132 center hole 136 incisions Section 138 140 Piston Cover 142 piston cover, 140 lip edge 144 The reinforced part of the lip edge 142.

Claims

1. A piston cover (50, 110, 120, 130, 140), the piston cover comprising a first end (52), a second end (54) and a compressible intermediate section (56). The piston covers (50, 110, 120, 130, 140) have a hollow, cylindrical body shape, and The second end portion (54) includes an opening (64) and a groove (60) at the outer periphery of the second end portion for mounting the second end portion (54) at the housing cover (96) of the brake actuator (92). Its features are, The second end portion (54) includes lip edges (62, 112, 122, 132, 142) that extend into an opening (64) of the second end portion (54), and The dimensions of the lip edges (62, 112, 122, 132, 142) are sufficient to separate the caliper (98) of the disc brake (90) from the middle section (56) of the piston cover (50, 110, 120, 130, 140) when the brake actuator (92) is engaged. During the braking action, the service brake spring of the brake actuator (92) is fully compressed.

2. The piston cover (50, 110, 120, 130, 140) according to claim 1, wherein, The dimensions of the lip (62, 112, 122, 132, 142) are sufficient to prevent contact between the intermediate section (56) and the cutting edge (100) of the caliper (98) during the braking action when the service brake spring is fully compressed.

3. The piston cover (50, 110, 120, 130, 140) according to claim 1 or 2, wherein, During the braking action when the service brake spring is fully compressed, the end (102) of the lip (62, 112, 122, 132, 142) covers the cutting edge (100) of the caliper (98).

4. The piston cover (50, 110, 120, 130, 140) according to claim 1 or 2, wherein, The lip edge (62, 112, 122, 132, 142) includes a central hole (80, 114, 124, 134), the diameter (82) of which is smaller than the outer diameter (74) of the intermediate section (56).

5. The piston cover (50, 110, 120, 130, 140) according to claim 4, wherein, The central holes (80, 114, 124, 134) of the lip edges (62, 112, 122, 132, 142) have a circular shape (80), an elliptical shape (114), or a polygonal shape (124).

6. The piston cover (50, 110, 120, 130, 140) according to claim 1 or 2, wherein, The lip margin (62, 112, 122, 132, 142) includes an incision (136) that divides the lip margin (62, 112, 122, 132, 142) into two or more segments (138).

7. The piston cover (50, 110, 120, 130, 140) according to claim 1 or 2, wherein, The lip edges (62, 112, 122, 132, 142) are made of the same material as the piston cover.

8. The piston cover (50, 110, 120, 130, 140) according to claim 1 or 2, wherein, The lip margins (62, 112, 122, 132, 142) include a reinforcing portion (144).

9. The piston cover (50, 110, 120, 130, 140) according to claim 8, wherein, The reinforcing part (144) is a fabric layer molded within the lip.

10. A brake actuator (92) comprising a piston cover (50, 110, 120, 130, 140) according to any one of claims 1 to 9.

11. The brake actuator (92) according to claim 10, comprising a push rod (94) having a section surrounded by the piston cover (50, 110, 120, 130, 140).

12. The brake actuator (1) according to claim 10 or 11, wherein, The brake actuator (92) is a brake chamber or spring brake actuator.

Images