DE-102024136450-B3 - Vehicle braking system

Abstract

The invention relates to a vehicle braking system with a multi-disc brake (7) by means of which a rotating transmission component, in particular an output shaft (17), can be braked during driving operation, wherein the multi-disc brake (7) is connected to a cooling/lubricating fluid circuit in which a cooling/lubricating fluid is circulated by a circulation pump (41) to cool the multi-disc brake (7). According to the invention, the braking system has a mechanical switching unit (51) which activates the circulation pump (41) when the brake is applied and deactivates the circulation pump (41) when the multi-disc brake (7) is not applied.

Inventors

• Alfred Rehr
• Martin Arbesmeier
• Vladimir Chernogorski
• Klaus Ternovan

Assignees

• AUDI AKTIENGESELLSCHAFT

Dates

Publication Date

20260513

Application Date

20241206

Claims (9)

1. Vehicle braking system with a multi-disc brake (7) by means of which a rotating transmission component (17) can be braked during driving operation, wherein the multi-disc brake (7) is connected to a cooling/lubricating medium circuit in which a cooling/lubricating medium is circulated by a circulating pump (41) to cool the multi-disc brake (7), wherein the braking system has a mechanical switching unit (51) which activates the circulating pump (41) when the multi-disc brake (7) is applied and deactivates the circulating pump (41) when the multi-disc brake (7) is not applied, characterized in that, to activate the circulating pump (41), the switching unit (51) establishes a drive connection between the still rotating transmission component (17) to be braked and a pump drive shaft (61) of the circulating pump (41).
2. Vehicle braking system according to Claim 1 , characterized in that the multi-plate brake (7) comprises: - an inner plate carrier (27) fixed to the transmission component (17) in a rotationally fixed manner, - an outer plate carrier (29) fixed to a transmission housing (31), - a plate pack arranged between the inner and outer plate carriers (27, 29), and - an actuator (33) which applies contact pressure to the plate pack for brake actuation.
3. Vehicle braking system according to Claim 2 , characterized in that during vehicle braking or deceleration, the contact pressure acts on the lamellar package while the inner lamellar carrier (27) is still rotating due to slippage, and that the slippage-induced rotation of the inner lamellar during vehicle deceleration is transmitted to the circulation pump (41) via the drive connection established by the mechanical switching unit (51) in order to activate it.
4. Vehicle braking system according to one of the preceding claims, characterized in that the switching unit (51) has a drive plate (57) which is arranged between two inner plates (35) which are axially adjustable but rotationally fixed on the inner plate carrier (27).
5. Vehicle braking system according to Claim 4 , characterized in that the driver lamella (57) is in addition to a positive locking connection with the inner lamella carrier (27) and in addition to a positive locking connection with the outer lamella carrier (29).
6. Vehicle braking system according to Claim 5 , characterized in that a synchronization process takes place during vehicle braking, in which the drive plate (57) is synchronized with the inner plates (35) with increasing contact pressure, i.e. the drive plate (57) is clamped between the two inner plates (35) in a force-fit manner, so that the inner plate carrier (27) drives the circulation pump (41) via this force-fit clamping connection.
7. Vehicle braking system according to Claim 5 or 6 , characterized in that during vehicle braking there is slip between the inner plates (35) and the outer plates (37) until the vehicle comes to a standstill, and that the synchronization process between the drive plate (57) and the inner plates (35) is completed at a significantly earlier time due to the low power consumption of the circulation pump (41).
8. Vehicle braking system according to Claim 5 , 6 or 7 , characterized in that the drive plate (57) is an integral part of the circulation pump (41), or that the drive plate (57) is designed as a gear which is connected to the pump drive shaft (61) via a gear stage (59).
9. Vehicle braking system according to one of the preceding claims, characterized in that a pressure line (42) of the circulation pump (41) opens into a distribution chamber (44) in the coolant/lubricant circuit, which is radially bounded to the outside by the inner lamella carrier (27), and that the coolant/lubricant can be injected into the distribution chamber (44), and from there flows into the lamella pack through passages (45) in the inner lamella carrier (27) due to centrifugal force, and after flowing through the lamella pack is collected radially outside and returned to a pump sump (47) which is in flow connection with a suction line (49) of the circulation pump (41), and/or that a heat exchanger (65) is connected in the coolant/lubricant circuit, which can be thermally coupled to a heating circuit (H), and that waste heat generated by the multi-plate brake is transferred via the heat exchanger (65). is purulent.

Description

The invention relates to a vehicle braking system with a multi-disc brake according to the preamble of claim 1. A vehicle braking system of this type features multi-disc brakes instead of conventional wheel disc brakes, enabling vehicle braking. Each multi-disc brake is connected to a cooling/lubricating fluid circuit in which a pump circulates the fluid to cool the brake. In the current state of the art, the circulation pump is activated not only when the multi-disc brake is applied, but also when the multi-disc brake is not applied. The coolant/lubricant pumped by the inactive multi-disc brake creates a drag torque. Furthermore, controlling the circulation pump's motor results in additional control and/or software complexity. From the DE 10 2024 101 021 A1 A vehicle braking system with a brake or clutch device is known. From the DE 10 2022 131 384 A1 A vehicle braking system is known in which the inner or outer plates of a multi-plate brake are connected to the rotor of an electric motor in a torque-transmitting manner. From the DE 10 2020 214 433 A1 A vehicle drive unit is known which has a cooling circuit in which a brake unit is integrated. The object of the invention is to provide a vehicle braking system with a multi-disc brake in which, compared to the prior art, drag losses are avoided in a simple manner and/or the control or software effort in controlling the circulation pump is reduced. The problem is solved by the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims. The invention relates to a vehicle braking system with a multi-disc brake, by means of which a rotating transmission component, in particular an output shaft, can be braked during driving. The multi-disc brake is connected to a cooling/lubricating fluid circuit in which a cooling/lubricating fluid is circulated by a pump to cool the multi-disc brake. According to the invention, the following measures are taken to avoid drag losses and to reduce the control and software effort required for controlling the pump: The braking system has a mechanical switching unit that activates the pump when the brake is applied and deactivates it when the multi-disc brake is not applied. To activate the circulation pump, the switching unit establishes a drive connection between the still-rotating transmission component to be braked and a pump drive shaft of the circulation pump. In this case, the still-rotating transmission component is also braked as a result of the activation of the mechanical circulation pump. Furthermore, no external energy is required to drive the circulation pump. The multi-plate brake consists of the following components: an inner plate carrier fixed to the transmission component, an outer plate carrier fixed to a transmission housing, a plate pack arranged between the inner and outer plate carriers, and an actuator that applies pressure to the plate pack for brake actuation. During vehicle braking, the actuator builds up contact pressure in the clutch pack, increasing the frictional engagement between the inner and outer clutch plates, while the inner clutch plate carrier continues to rotate due to slippage. When the vehicle is stationary, the contact pressure is sufficient to create a complete frictional engagement within the clutch pack. In a specific embodiment, the invention utilizes the fact that the inner lamella carrier continues to rotate during vehicle deceleration: Accordingly, the slip-induced rotation of the inner lamellae occurring during the friction build-up phase can be transferred to the pump drive shaft via the drive connection established by the mechanical switching unit in order to activate the circulation pump. To provide this drive connection, the switching unit has a drive plate arranged between two inner plates. The inner plates are axially adjustable on the inner plate carrier, but are guided against rotation. In contrast, the drive plate is not positively connected to either the inner or outer plate carrier; that is, the drive plate can rotate freely with respect to both the inner and outer plate carriers. During vehicle deceleration, a synchronization process takes place in which the drive plate is forced between the two inner plates. The inner vane carrier is clamped securely, i.e., synchronized with the inner vanes. The inner vane carrier drives the pump drive shaft via this positive clamping connection. To create a structurally simple drive connection, the drive vane can be designed as a gear that is connected to the pump drive shaft via a gear stage. In the coolant/lubricant circuit, a pressure line from the circulation pump can lead into a distribution chamber, which is radially bounded to the outside by the inner fin carrier. The coolant/lubricant can be injected into the distribution chamber. From there, the coolant/lubricant flows, driven by centrifugal force, through openings in the inner fin carrier into the fin pack. After passing through the fi