BRAKE CALIPER UNIT

Description

[0001] The present invention relates to a brake caliper unit for disc brakes, comprising a carrier forming a caliper, a pneumatically operated piston / cylinder arrangement arranged in the caliper, the piston and cylinder of which have a non-circular cross-section, and a brake pad.

[0002] Brake caliper units of the generic type are known from EP 2 754 914 A1 and GB 2 089 916 A.

[0003] The brake caliper unit known from EP 2 754 914 A1 is intended for use on a rail vehicle. It comprises a cylinder and a brake block movably arranged within the cylinder. The brake block interacts with an adjustment device, which in turn has a gap mechanism with a spring-loaded pin. The purpose of the gap mechanism is to compensate for wear and ensure a consistently constant gap between the brake block and the associated brake disc.

[0004] Disc brake systems are well known in the art and are used extensively. They consist of rotating discs mounted on axles and shafts which pass through a slot in a brake caliper unit. Pistons actuated by a pressure medium are arranged in the brake caliper unit. When the pressure increases, these pistons exert pressure on a brake pad, which is usually positioned in a plate-like manner between the piston and the disc. The advancing piston presses the brake pad against the disc, thus braking the disc. Systems are known in which the pressure is exerted on one side, so that a brake pad is arranged in a floating manner relative to a brake disc, parallel to its friction surface. Brake pads positioned on both sides of the disc are thus guided onto the brake disc.Also known are two-sided operated brake caliper units, in which pressure is applied to pistons on both sides of the brake disc so that brake pads are driven forward on both sides.

[0005] Increasing efforts are being made to develop pneumatic braking systems that can meet these mechanical requirements. The main reason for this is that the brake fluids used in hydraulic braking systems are hygroscopic, meaning they age through water absorption, significantly weakening their compression-free properties. These brake fluids must be replaced frequently, resulting in a significant environmental impact and high costs for operators.

[0006] Pneumatic braking systems pose the problem of the necessary pressure application. Conventional brake pistons are round-cylindrical units that apply pressure to plate-shaped brake pad units. The piston area available for pneumatic pressure is small relative to the force required, so the pneumatic pressure must be set extremely high. This leads to high operating costs and high design costs for the pneumatic system, lines, seals, and the like.

[0007] Pneumatic pressures generally cannot be as high as hydraulic ones because air can be compressed more easily. Generating high pneumatic pressures is uneconomical.

[0008] Based on the above-described prior art, the invention is based on TaskThe aim is to further develop a brake caliper unit of the generic type in such a way that it is suitable for use in pneumatic brake systems while at the same time having a compact design.

[0009] For technical Solution To achieve this goal, a brake caliper unit having the features of patent claim 1 is proposed. Further advantages and features emerge from the subclaims.

[0010] It is intended that the piston and cylinder of a piston-cylinder arrangement have a non-circular cross-section, meaning they are not circular but can have a non-circular cross-sectional shape. According to an advantageous proposal of the invention, an elliptical shape is proposed. However, a polygonal shape, a polygon, or a cycloid are also generally suitable. This makes it possible to design the piston surface, which is subjected to pressure medium, correspondingly large.

[0011] According to the invention, the piston-cylinder arrangement is designed as a tandem piston assembly. In the art, a tandem piston, at least in the context of the present invention, is understood to mean an arrangement where piston units connected in series are pressurized, with the pressure on one of the pistons correspondingly increasing the pressure on the subsequent piston. Similar to known tandem cylinders, two individual pressure pistons are mounted one behind the other. A primary piston is actuated by the tappet but simultaneously pressurized. In addition, the piston moving the tappet is also pressurized. The term "tandem brake cylinder" is used analogously in the context of the present invention; it essentially refers to a series connection of pressure piston units, with the result that the resulting pressure is correspondingly increased. This increase can exceed 75%.

[0012] The inventive measures of increasing the effective piston area and the tandem design generate sufficient pressure through a pneumatic system to exert sufficient force on the brake pads. The required installation space and thus the overall weight are not increased compared to existing systems.

[0013] According to the invention, at least two piston / cylinder assemblies are arranged side by side. It can also be a parallel arrangement of several piston / cylinder assemblies in order to increase the friction surface by using a corresponding number of brake pads.

[0014] Advantageously, the brake pistons are designed for a floating arrangement on a wheel assembly. This means that the brake piston can move parallel to the friction surface of the brake disc relative to the disc. This ensures that the brake disc is always automatically centered in the brake caliper slot.

[0015] Advantageously, the carrier can have a receiving chamber for the piston / cylinder assembly. The piston / cylinder assembly has a pot-shaped piston with a non-circular cross-section that serves to propel the brake pad.

[0016] According to the invention, the tandem configuration is formed by two cup-shaped piston units guided one inside the other, with the inner piston unit forming a cylinder chamber for a piston and the piston rod connected to the piston extending through it. This piston rod, in turn, is connected to the outer cup-shaped piston, which accommodates the inner cup-shaped piston within its interior. The outer cup-shaped piston unit thus forms a cylinder chamber for the inner cup-shaped unit, which thus forms another piston.

[0017] The invention proposes extremely effective features for a brake caliper unit which is suitable for building up sufficient pressure when operating with a pneumatic pressure medium, i.e. compressed air.

[0018] Further advantages and features of the invention will become apparent from the following description based on the figures. These show: Fig. 1 is a side view of an embodiment of a brake caliper unit according to the invention; Fig. 2 is a section along the line AA according to Fig. 1K; Fig. 3 is a partially sectioned plan view of the brake caliper unit according to Fig. 1 ; Fig. 4 a partially sectioned exploded view of a piston-cylinder arrangement according to the invention.

[0019] In the figures, identical elements are provided with identical reference numerals.

[0020] The Figures 1 to 3 show the general structure of a brake calliper unit 1, which consists of a carrier 2, in which receiving spaces 3 for brake pistons are formed. In a known manner, a brake calliper unit 1 runs over a Fig. 1 indicated brake disc 4, which runs between two opposite brake piston receiving spaces 3, as the Figures 2 and 3In the embodiment shown, the support 2 is formed in two parts and the two halves are connected by screws 5.

[0021] Fig. 4 shows the structure of a brake piston unit according to the invention, which is arranged in a receiving space 3 in the carrier.

[0022] The element designated brake piston 10 presses a brake pad (not shown) against the disc with its outer pressure surface 11. For this purpose, the brake piston 10 is moved by means of a piston 12, which is guided in a cylinder 13 and is connected to the brake piston 10 at the connection 19 via its piston rod 16. Pressure medium lines 15 are formed in the cylinder 13 to bring the pressure medium into the area inside the cylinder 13 below the piston 12. The piston 12 is thus pushed forward and in this way also pushes the brake piston 10 forward. The piston rod 16 projects through a cylinder head plate 17, which has an opening 18 for this purpose. The cylinder head plate 17 is arranged on the cylinder 13 so as to close it off. If the piston 12 is moved forward due to the effect of the pressure medium in the cylinder, the brake piston 10 is also moved forward via the piston rod 16, which is fastened in the connection 19 of the brake piston 10.An additional space is created between the cylinder head plate 17 and the interior of the brake piston 10. Additional pressure medium is fed into this resulting gap via a pressure medium line 20, generating additional pressure at this point, allowing the brake piston 10 to exert additional force. The effective piston areas add up, thus requiring less pressure for the same braking force.

[0023] In the illustrated embodiment, three elliptical receiving spaces 3 for brake piston units are formed in the carrier. The elliptical contour enables a large piston surface and thus a high level of force transmission while simultaneously preventing rotation. The individual elements of the piston unit can be turned out of round, i.e., elliptically, making the production of the individual brake piston units and the receiving spaces in the caliper extremely simple and cost-effective.

[0024] The described embodiments are for illustrative purposes only and are not restrictive. Reference symbol

[0025] 1Brake caliper unit 2Carrier 3Receptacle 4Brake disc 5Screw 6Openings 10Brake piston 11Pressure surface 12Piston 13Cylinder 14Seal 15Pressure medium line 16Piston rod 17Cylinder head plate 18Opening 19Connection 20Pressure medium line

Claims

1. A brake caliper unit (1) for disc brakes, comprising a support (2) forming the caliper, a pneumatically operated piston-cylinder arrangement arranged in the caliper, the pistons (10, 12) and cylinder (13) of which have a non-circular cross-section, and a brake lining, wherein the pistons (10, 12) and the cylinder (13) of the piston-cylinder arrangement are designed as a tandem-piston subassembly, characterized in that the tandem-piston subassembly is formed by two pot-shaped piston units which are guided in one another, wherein the inner piston unit forms a cylinder chamber for a first piston (10) and is penetrated by a piston rod (16) which is connected to the first piston (10), wherein the first piston (10) is designed as a pot-shaped piston which, in its interior, forms a cylinder chamber for a further piston (12), wherein the further piston (12) is guided in a cylinder (13) which is closed by a cylinder head plate (17), wherein the piston rod (16) penetrates the cylinder head plate (17), for which purpose the cylinder head plate (17) comprises an opening (18).

2. The brake caliper unit (1) according to claim 1, characterized in that the piston (10) and the associated cylinder (13) have an elliptical cross-section.

3. The brake caliper unit (1) according to any one of the preceding claims, characterized in that at least two piston-cylinder arrangements are arranged side by side.

4. The brake caliper unit (1) according to any one of the preceding claims, characterized in that the same is designed for floating arrangement on a wheel subassembly.

5. The brake caliper unit (1) according to any one of the preceding claims, characterized in that the support (2) comprises an accommodation chamber for the piston-cylinder arrangement.