Brake system with a parking brake

Abstract

The invention relates to a brake system with a parking brake, comprising: a brake pad (2) that can be pressed against a running surface of a rail wheel (1); a piston (10) to which a pressure medium can be supplied, which piston is operatively connected to the brake pad (2) and is partially accommodated in a brake cylinder (9); a spring system (4) which is coupled to the piston (10) and the brake pad (2); and a cam disk (15) which is resiliently mounted on the spring system (4) and is coupled to the piston (10) and the brake pad (2).

Description

[0001] 2024PF00106 06.12.2024

[0002] Braking system with a parking brake

[0003] DESCRIPTION

[0004] The invention relates to a braking system with a parking brake according to the preamble of claim 1.

[0005] A braking system of this type, which is used particularly in a rail vehicle, is known from DE 10 2022 122 146 A1.

[0006] In this braking system, where a brake pad is pressed against the running surface of a rail wheel, the pressure of the brake pad against the rail wheel is achieved via a piston that is axially movable in a brake cylinder.

[0007] Since the stiffness of the force-transmitting components in certain types of actuators, such as brake calipers or block brake units, is too great to compensate for stroke losses, for example due to cooling of the friction partners, a spring system is interposed between the piston and the brake pad.

[0008] The characteristics of this spring system are designed in such a way that it is able to compensate for the aforementioned stroke losses and only becomes active above a predetermined force, which is above the force required for normal service brake actuation.

[0009] Such a braking system has proven itself in practice.

[0010] The object of the present invention is to further develop such a braking system in such a way that it is possible to maintain the braking position even in the event of a sudden drop in the contact pressure on the piston.

[0011] This problem is solved by a braking system with a parking brake having the features of claim 1.

[0012] The braking system according to the invention comprises a brake pad that can be pressed against a rail wheel, a piston that can be actuated with a pressure medium and is in operative connection with the brake pad, and which is partially received in a brake cylinder, as well as a spring system coupled to the piston and the brake pad. 2024PF00106

[0013] - 2 -

[0014] The braking system also features a cam disc that is spring-mounted on the spring system and coupled to the piston and the brake pad.

[0015] During service braking, the cam disc is moved in such a way that the brake pad is pressed against the rail wheel.

[0016] The cam disc is not fixed to a main housing at one end, but is spring-loaded via the spring system in order to reduce the stiffness of the entire power transmission unit.

[0017] Advantageous embodiments of the invention are the subject of the dependent claims.

[0018] According to one embodiment, the spring system comprises a spring unit housed in a housing with a first housing section and a second housing section axially displaceable to the first housing section, wherein the cam disc is coupled to the second housing section.

[0019] According to a further development, the cam disc is pivotably mounted about a pivot axis, the pivot axis of this cam disc being attached to the second housing section.

[0020] This allows the cam disc to rotate, thereby changing the force acting on the brake pad.

[0021] According to another preferred embodiment, a locking unit is arranged on a piston rod of the piston, with which the piston can be locked in a predetermined position.

[0022] This allows the piston to be locked in a holding position of the brake pad, so that the braking force is maintained even if the pressure in the brake cylinder drops.

[0023] The preload force of the spring unit is preferably set to a value above a maximum operating braking force and below a minimum locking force. 2024PF00106

[0024] - 3 - braking force set. This means that during service braking, the cam disc is virtually rigidly mounted on the spring system and only becomes spring-mounted after the service braking force has been exceeded.

[0025] According to a further advantageous embodiment, the second housing section of the spring system is designed as a frame rotatable about a housing axis of rotation, wherein the housing axis of rotation is arranged parallel and spaced apart from the pivot axis of the cam disc.

[0026] The spring unit is preferably designed as a compression spring, in particular as a helical spring.

[0027] It is also conceivable to design the spring unit as a spring package.

[0028] A preferred embodiment is explained below with reference to the accompanying drawing. It shows:

[0029] Figure 1 shows a schematic side view of a parking brake of the braking system.

[0030] In the following figure descriptions, terms such as top, bottom, left, right, front, rear, etc., refer exclusively to the exemplary representation and position of the brake pad, piston, spring system, cam disc, and the like as chosen in the respective figures. These terms are not to be understood as restrictive; that is, these references may change due to different working positions, mirror-symmetrical design, or similar factors.

[0031] As can be seen in Figure 1, the braking system has a brake pad 2 with a brake block 3 attached to it, which can be pressed against a rail wheel 1 in the event of braking.

[0032] The parking brake has a piston 10 guided axially to a cylinder axis within a brake cylinder 9, with a piston rod 11 and a piston surface 12 located at one end of the piston rod 11, the outer surface of which rests tightly against the inner wall of the brake cylinder 9. 2024PF00106

[0033] - 4 -

[0034] A pressure medium, in particular compressed air or a pressure fluid, can be supplied via a connection 13 into the chamber limited by the piston area and the cylinder wall of the brake cylinder 9.

[0035] The end of the piston rod 11 protruding from the brake cylinder 9 is coupled to a first end of a cam disc 15.

[0036] A second end of the cam disc 15 is coupled to a spring system 4 via a pivot axis 17.

[0037] The spring system 4 comprises a spring unit 6 housed in a housing 5 with a first housing section 7 and a second housing section 8 which is axially displaceable relative to the first housing section 7. The pivot axis 17 is attached to the second housing section 8.

[0038] The first housing section 7 is fixedly attached to a main housing which is not shown here.

[0039] Furthermore, a locking unit 14 is arranged on a piston rod 11 of the piston 10, with which the piston 10 can be locked in a predetermined position.

[0040] The locking unit 14 is controlled in such a way that it blocks the piston 10 when it has been moved into the braking position by the pressure medium and thus fixes the piston rod 11 in the braking position, so that the braking position of the piston rod 11 is maintained even if the brake operating pressure decreases or fails.

[0041] The preload force of the spring unit 6 is set to a value above a maximum service braking force and below a minimum parking braking force.

[0042] This means that the cam disc 15 is rigidly attached up to the maximum operating braking force via the spring system 4, which is not springy up to this force. 2024PF00106

[0043] - 5 - which results in unchanged braking parameters up to the maximum operating pressure.

[0044] If this maximum service braking force is exceeded, the interposition of the spring system 4 results in a flexible transmission module, since the spring unit 6 can yield above the maximum service braking force.

[0045] In one embodiment, the second housing section 8 is designed as a frame rotatable about a housing rotation axis, wherein the housing rotation axis is arranged parallel and spaced apart from the pivot axis 17 of the cam disk 15.

[0046] The spring unit 6 is preferably designed as a compression spring, in particular as a helical spring. It is also conceivable that the spring unit 6 is designed as a spring assembly.

[0047] The suspension of the cam disc 15 via the spring system 4 ensures that a small amount of play in the components of the brake system does not lead to a critical loss of braking force, as this play is compensated for by the spring system 4.

[0048] 2024PF00106

[0049] - 6 -

[0050] REFERENCE MARK LIST

[0051] 1 rail wheel

[0052] 2 brake pads

[0053] 3 brake pads

[0054] 4 spring system

[0055] 5 cases

[0056] 6 spring unit

[0057] 7 first housing section

[0058] 8 second housing section

[0059] 9 brake cylinders

[0060] 10 pistons

[0061] 11 Piston rod

[0062] 12 piston area

[0063] 13 connection

[0064] 14 Locking unit

[0065] 15 Cam disc

[0066] 16 Connecting rod

[0067] 17 Swivel axis

Claims

2024PF00106 - 7 - Claims 1. Braking system with a parking brake, comprising a brake pad (2) that can be pressed against a rail wheel (1), a piston (10) that can be acted upon by a pressure medium and is in operative connection with the brake pad (2) and is partially received in a brake cylinder (9), a spring system (4) coupled to the piston (10) and the brake pad (2), characterized by a cam disc (15) that is resiliently mounted on the spring system (4) and is coupled to the piston (10) and the brake pad (2).

2. Brake system according to claim 1, characterized in that the spring system (4) has a spring unit (6) received in a housing (5) with a first housing section (7) and a second housing section (8) axially displaceable to the first housing section (7), wherein the cam disc (15) is coupled to the second housing section (8).

3. Brake system according to claim 1, characterized in that the cam disc (15) is pivotably mounted about a pivot axis (17), wherein the pivot axis (17) is attached to the second housing section (8).

4. Brake system according to one of the preceding claims, characterized in that a locking unit (14) is arranged on a piston rod (11) of the piston (10), with which the piston (10) can be locked in a predetermined position.

5. Braking system according to one of the preceding claims, characterized in that 2024PF00106 - 8 - a preload force of the spring unit (6) is set to a value above a maximum service braking force and below a minimum parking braking force.

6. Brake system according to one of the preceding claims, characterized in that the second housing section (8) is designed as a frame rotatable about a housing rotation axis, wherein the housing rotation axis is arranged parallel and spaced away from the pivot axis (17) of the cam disc (15).

7. Brake system according to one of the preceding claims, characterized in that the spring unit (6) is designed as a compression spring, in particular as a helical spring.

8. Braking system according to one of claims 1 to 6, characterized in that the spring unit (6) is designed as a spring pack.

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