Method and device for temperature control of a disc brake

Abstract

Method for temperature control of a disc brake in a motor vehicle (20), comprising the following features: - ambient conditions are monitored by means of sensors of the motor vehicle (20) and - depending on the ambient conditions, the disc brake is heated, characterized by the following features: - the ambient conditions include an air humidity (22) and an outside temperature (24), - based on the ambient conditions, an operating temperature of the disc brake is derived from the ambient conditions by a control unit of the motor vehicle (20) using a temperature model of the disc brake stored in the control unit, - the heating takes place inductively by means of electrical energy depending on the operating temperature in the event of a sudden drop in the outside temperature (24), if the relative air humidity (22) exceeds a predetermined threshold value before the drop and - the energy is taken from a traction battery of the motor vehicle (20).

Description

[0001] The present invention relates to a method for temperature control of a disc brake. The present invention further relates to a corresponding device, a corresponding computer program, and a corresponding storage medium. State of the art

[0002] During the development of road vehicles, the aim is generally to minimize rolling resistance. For example, in vehicles with disc brakes, the restoring forces are increased to reduce the residual friction between the brake pad and the disc. This can sometimes lead to a phenomenon known as "cold running," in which the ambient temperature of the brake disc drops below 0 °C. This is particularly true for electric vehicles with regenerative braking systems, which are designed to achieve slight deceleration through recuperation, largely without relying on mechanical braking.

[0003] Under changing environmental conditions such as fluctuating temperature or humidity, as might occur when entering or exiting tunnels, parking garages, or underground car parks, condensation can form on the brake disc, which can then freeze when the disc cools down. Such icing can negatively reduce braking performance. In the design of an electric vehicle, this risk could be addressed by increasing braking force at the expense of regenerative braking, but this would reduce the vehicle's range and increase audible or perceptible vibrations (noise, vibration, harshness; NVH).

[0004] Against this background, CN 212429582 U and CN 212429576 U reveal disc brakes with a heated brake cylinder.

[0005] CN 210397529 U discloses a brake caliper with a piston, the hydraulic medium of which flows through a heating device.

[0006] DE 10 2007 017 976 B4 discloses a switchable brake or clutch with two contact bodies which can be coupled or decoupled from each other by a switching coil, and a heating device.

[0007] EP 1 840 402 B2 discloses an electromagnetic brake with an anti-condensation heater.

[0008] DE 103 60 496 B4 discloses a disc brake with two brake pads, a brake disc and an induction heater which is activated when a moisture value determined by a moisture sensor exceeds a threshold value. Disclosure of the invention

[0009] The invention provides a method for temperature-controlling a disc brake, a corresponding device, a corresponding computer program and a corresponding machine-readable storage medium according to the independent claims.

[0010] One advantage of this solution is that the brake disc can be specifically temperature-controlled under the desired driving conditions.

[0011] Further advantageous embodiments of the invention are specified in the dependent claims. For example, in an electric vehicle, the brake disc can be inductively heated by means of electrical energy drawn from the vehicle's traction battery. Such contactless heating does not affect the NVH (noise, vibration, and harshness) and is therefore imperceptible to the vehicle occupants. List of characters

[0012] An embodiment of the invention is shown in the drawings and is described in more detail below. Fig. Figure 1 shows a top view of a device according to the invention. Fig. Figure 2 shows a side view of the device from the left. Fig. Figure 3 shows a relevant driving situation. Embodiments of the invention

[0013] The Fig. 1 and Fig. Figure 2, taken together, illustrates the construction of a device (10) according to the invention in the form of a brake disc heater, which is capable of preventing the icing of a generic disc brake. For this purpose, an induction coil (13) serves in particular to introduce energy into the brake disc (12) in order to prevent it from cooling down to a critical temperature range in which the braking performance could decrease.

[0014] The induction coil (13) may be mounted separately on the braked axle or integrated into an existing component such as the brake caliper (11) or the wheel bearing.

[0015] In accordance with the invention, the disc brake is heated only when ambient conditions such as outside temperature or humidity indicate a need for heating. Such conditions are monitored by suitable sensors in the vehicle and evaluated by an internal control unit – for example, based on a temperature model of the brake.

[0016] This function will now be exemplified by the following: Fig. The application case shown in Figure 3 illustrates this: The motor vehicle (20) travels through a mountain tunnel (21) with high humidity (22) in cold, wet weather, which is detected by a humidity sensor on the motor vehicle (20). Upon exiting (23) the tunnel (21), the temperature sensors on the motor vehicle (20) also register a sudden drop in the outside temperature (24).

[0017] The control unit in question could deduce from such environmental conditions and their progression over time that the operating temperature of the disc brake would drop below freezing without countermeasures being taken. In this case, there would be a risk that any condensation that had formed on the brake disc (12) while passing through the tunnel (21) could cause it to freeze. In view of this safety risk, the control unit would automatically activate the induction coil (13). QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 212429582 U

[0004] CN 212429576 U

[0004] CN 210397529 U

[0005] DE 102007017976 B4

[0006] EP 1840402 B2

[0007] DE 10360496 B4

[0008]

Claims

[1] Method for tempering a disc brake in a motor vehicle (20), characterized by following features: - environmental conditions are monitored by means of sensors of the motor vehicle (20) and - Depending on the ambient conditions, the disc brake is heated. [2] Method according to claim 1, characterized by following features: - the ambient conditions include an outside temperature (24) and - heating occurs when the outside temperature drops suddenly (24). [3] Method according to claim 2, characterized by following features: - the ambient conditions include humidity (22) and - heating occurs when the relative humidity (22) exceeds a predetermined threshold before the drop. [4] Method according to one of claims 1 to 3, characterized by following features: - based on the ambient conditions, an operating temperature of the disc brake is calculated and - heating depends on the operating temperature. [5] Method according to claim 4, characterized by following features: - the calculation is carried out by a control unit of the motor vehicle (20) and - the operating temperature is derived from the ambient conditions using a temperature model of the disc brake stored in the control unit. [6] Method according to one of claims 1 to 5, characterized by following features: - heating is done by electrical energy and - the energy is taken from a traction battery of the motor vehicle (20). [7] Method according to claim 6, characterized by following feature: - heating is done inductively. [8] Device (10) for carrying out a method according to claim 7, characterized by following features: - a brake calliper (11), - a brake disc (12) encompassed by the brake calliper (11) and - an induction coil (13) preferably integrated in the brake calliper (11) for heating the brake disc (12). [9] Computer program which is designed to carry out all the steps of a method according to one of claims 1 to 7. [10] A machine-readable storage medium having stored thereon a computer program according to claim 9.

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