KR20130102069A - Brake actuation unit for a motor vehicle brake system and motor-pump unit for providing a vacuum for a brake actuation unit of a motor vehicle brake system - Google Patents

Abstract

The present invention provides a brake drive unit (1, 1 ', 1'') for a motor vehicle brake system having a vacuum actuated brake booster (2) and a motor pump assembly (3) provided to generate underpressure. The assembly is associated with a brake drive unit 1, 1 ′, 1 ″ for an automobile brake system comprising a pump connected to a vacuum actuated brake booster 2 and an electric motor for driving the pump.
According to the invention, in order to lower the sound pressure level in the interior of the vehicle, additional silencer elements 4, 4 ′, 4 ″ are provided at the connection between the vacuum actuated brake booster 2 and the pump.

Description

Brake ACTUATION UNIT FOR A MOTOR VEHICLE BRAKE SYSTEM AND MOTOR-PUMP UNIT FOR PROVIDING A VACUUM FOR A BRAKE ACTUATION UNIT OF A MOTOR VEHICLE BRAKE SYSTEM}

The invention comprises a vacuum actuated brake booster and a motor pump assembly provided to generate underpressure in accordance with the preamble of claim 1, the motor pump assembly comprising a pump connected to a vacuum actuated brake booster and an electric motor for driving the pump. It relates to a brake drive unit for a vehicle brake system comprising a, and relates to a motor pump assembly for a brake drive unit of a vehicle brake system for generating underpressure according to the preamble of claim 8.

In order to provide a negative pressure (vacuum) for the pneumatic brake booster, which divides the internal space into at least one vacuum chamber and one working chamber, a vacuum pump is used which absorbs the remaining air from the vacuum chamber and discharges the remaining air to the atmosphere. For this purpose in the automotive industry, vane-type pumps or swing vane-type pumps are generally used. These pumps exhibit high friction because of their principle of operation and must be lubricated to obtain an acceptable life. The vacuum pump, which has vanes and is also driven by the internal combustion engine of the motor vehicle, is connected to the oil circuit of the internal combustion engine. Nevertheless, a significant portion of the power output by the internal combustion engine needs to be consumed to drive this type of pump. This is even the case when the vacuum in the chamber to be evacuated has already been completely produced. Therefore, the vacuum pump is driven using electric energy, and is convenient to be activated only when the absolute pressure of the vacuum chamber rises above a predetermined value.

Moreover, in motor vehicles having electric and / or hybrid drives, the vacuum pump cannot be driven by the internal combustion engine or can be driven intermittently. Electrically driven vacuum pumps are therefore used in such vehicles.

Providing a lubrication circuit for an electrically driven pump or connecting an electrically driven pump to the lubrication circuit involves disproportionately high costs. Thus, only dry operating vacuum pumps are available for use in motor vehicles having brake systems with electrically driven vacuum pumps. For this purpose, vane-type pumps use self-lubricating material graphite, which is manufactured at the required precision, with enormous cost. Therefore, efforts have been made to use a diaphragm pump for the electrical provision of brake vacuum.

For example, DE 10 2007 005 223 A1 describes a general brake drive unit having a motor pump assembly. There is a very high demand for acoustic comfort of automotive parts in the automotive industry, and a robust and durable pump with very low noise emission is required from suppliers. In order to meet the needs, in known motor pump assemblies, the outlet ducts in the operating chamber cover and the pump housing are often arranged in such a way that the air discharged out of the operating chamber is guided into the inner space of the pump housing surrounding the crank drive. have. Furthermore, an air outlet unit is provided that allows for the quiet discharge of air from the interior space through the conversion of air. Since the discharged air is not directly directed to the atmosphere, the internal space, also called the crank chamber, acts as a silencer chamber. By air switching in the air outlet unit, it is possible that the noise level is additionally significantly lowered to such an extent that exhaust noise is virtually eliminated.

However, during operation of the motor pump assembly, unwanted noise that can be amplified by the brake booster and can be transmitted to the interior space of the vehicle can also occur in the vacuum hose.

The increased use of motor vehicles with electric drives increases the demand for acoustic installations for brake drive units and motor pump assemblies.

It is therefore an object of the present invention to provide a brake drive unit having a motor pump assembly and a motor pump assembly which takes into account the increased demand for acoustic comfort.

This object is achieved according to the brake drive unit and motor pump assembly of the type described above by means of the features of claims 1 and 8.

Additional features, advantages, and possible applications of the present disclosure will appear from the following description and dependent claims of a number of exemplary embodiments based on the drawings.

1 is a schematic view of a first embodiment of a brake drive unit according to the present disclosure and a motor pump assembly according to the present disclosure;
2 is a schematic view of a second embodiment of a brake drive unit according to the present disclosure and a motor pump assembly according to the present disclosure, and
3 is a schematic view of a third embodiment of a brake drive unit according to the present disclosure and a motor pump assembly according to the present disclosure;

1 shows a brake drive unit 1 for an automobile brake system having a vacuum actuated brake booster 2 and a motor pump assembly 3 provided for negative pressure generation. The motor pump assembly 3 comprises a pump which is connected to the vacuum actuated brake booster 2 via a connecting line 6 and an electric motor for driving the pump.

For example, the pump (not shown in more detail) is provided in the form of a diaphragm pump with a pump housing and at least one actuating diaphragm, which actuates the actuating chamber with the actuating chamber cover and also cranks it. It can be moved by a drive and the working chamber is assigned an inlet duct with an inlet valve and an outlet duct with an outlet valve.

The pump is ideally in the form of a double diaphragm pump with two opposing actuating diaphragms.

In order to account for the high demands of automotive manufacturers for the acoustic comfort of the motor pump assembly, the outlet duct is arranged in such a way that the air exhausted out of the working chamber is guided into the interior space surrounding the crank drive of the pump housing, An air outlet unit is provided that allows for quiet discharge of air from the air.

However, while the motor pump assembly 3 is in operation, unwanted noise may occur in the connecting line 6 between the pump and the vacuum actuated brake booster 2, which noise may be generated in the vacuum actuated brake booster 2. Is further amplified and transmitted to the interior space of the car. In particular, the increased use of motor vehicles with electric drives increases the demand for acoustics in the brake drive unit 1 and the motor pump assembly 3.

In order to account for the increasing demand for acoustic comfort, in all the exemplary embodiments described below, in order to lower the sound pressure level in the interior space of the vehicle, additional silencer elements 4, 4 ′, 4 ″ are vacuum operated brakes. Provided at the connection between the booster 2 and the pump, the additional silencer elements 4, 4 ′, 4 ″ are arranged directly at the vacuum inlet or vacuum port 5 of the pump, or in embodiments not described It may be integrated with the pump.

Due to the integration of the additional silencer elements 4, 4 ′, 4 ″ in the pump, it is possible to advantageously eliminate the individual fastening with the motor pump assembly 3 or with additional automotive parts.

By arranging additional silencer elements 4, 4 ′, 4 ″ in the vacuum port 5 of the pump, it is possible to prevent pressure pulsations and vibrations in the connection line 6 and the noise generated thereby.

As can be seen from FIG. 1, in the first exemplary embodiment a pressure equalization vessel 7 is provided which allows for cross-sectional expansion of the connecting line 6 as an additional silencer element 4. The generated pressure pulsations and vibrations can be substantially eliminated by the cross sectional expansion.

 2 shows a second exemplary embodiment of a brake drive unit 1 ′ according to the invention. As can be seen from the figure, there are cases where the additional silencer element 4 'additionally has a Helmholtz resonator 8. The Helmholtz resonator 8 absorbs disturbing frequency components while the pressure equalization vessel 7 converts sound wave energy remaining by friction into heat.

A variant embodiment according to FIG. 3 provides that the additional silencer element 4 ″ additionally has a capillary tube 9. The disturbing frequency component can be absorbed by means of change in the cross-sectional area of the connecting line 6 to be traversed by the flow.

1 brake drive unit
1 'brake drive unit
1 '' brake drive unit
2 vacuum operated brake boosters
3 motor pump assembly
4 additional silencer elements
4 'additional silencer element
4 '' additional silencer element
5 vacuum ports
6 connection line
7 Pressure Equalization Vessel
8 Helmholtz Resonators
9 capillary

Claims (11)

As a brake drive unit (1, 1 ', 1'') for an automobile brake system having a vacuum actuated brake booster (2) and a motor pump assembly (3) provided to generate underpressure,
The motor pump assembly includes a pump connected to the vacuum operated brake booster 2 and an electric motor for driving the pump,
The pump is provided in the form of a diaphragm pump having a pump housing and at least one actuating diaphragm,
The actuating diaphragm defines an actuation chamber together with an actuation chamber cover, and can also be moved by a crank drive,
The working chamber is assigned an inlet duct with an inlet valve and an outlet duct with an outlet valve, the outlet duct arranged in such a way that the air exhausted out of the working chamber is guided into an interior space surrounding the crank drive of the pump housing. Become,
In a brake drive unit (1, 1 ', 1'') for an automobile brake system, provided with an air outlet unit that enables quiet discharge of air from the interior space.
For lowering the sound pressure level in the interior of the vehicle, an additional silencer element 4, 4 ′, 4 ″ is provided at the connection between the vacuum actuated brake booster 2 and the pump. Brake drive units (1, 1``, 1 ''). The method of claim 1,
A brake drive unit 1, 1 ″, 1 ″, characterized in that the pressure equalization vessel 7 is provided as additional silencer elements 4, 4 ′, 4 ″. 3. The method of claim 2,
Said further silencer element (4 ′) has a Helmholtz resonator (8) which is a brake drive unit (1 ′) for an automobile brake system. 3. The method of claim 2,
The further silencer element (4 '') is a brake drive unit (1 '') for an automotive brake system further having a capillary tube (9 ''). The method according to any one of claims 1 to 4,
The further silencer element (4, 4 ', 4'') is arranged directly at the vacuum inlet of the pump (1, 1', 1 ''). The method according to any one of claims 1 to 4,
And said additional silencer element is arranged in said pump. The method of claim 1,
The pump is provided in the form of a double diaphragm pump with two opposing actuating diaphragms, the actuating diaphragms being clamped between the pump housing and the working chamber cover in each case, thereby remind A brake drive unit (1, 1 ', 1'') for defining a working chamber, which can be moved by a crank drive having an eccentric shaft and a connecting rod. A motor pump assembly (3) for generating underpressure for a brake drive unit for an automobile brake system having a vacuum actuated brake booster (2),
The motor pump assembly includes a pump and an electric motor driving the pump,
The pump is provided in the form of a diaphragm pump having a pump housing and at least one actuating diaphragm,
The actuating diaphragm defines an actuation chamber together with an actuation chamber cover, and can also be moved by a crank drive,
The working chamber is assigned an inlet duct with an inlet valve and an outlet duct with an outlet valve, the outlet duct arranged in such a way that the air exhausted out of the working chamber is guided into an interior space surrounding the crank drive of the pump housing. Become,
In the motor pump assembly (3), provided with an air outlet unit that enables quiet discharge of air from the interior space.
Additional silencer elements 4, 4 ′, 4 ″ generate underpressure for the brake drive units 1, 1 ′, 1 ″ of the motor vehicle brake system, characterized in that they are arranged directly to the vacuum inlet of the pump. Motor pump assembly (3). The method of claim 8,
The pressure equalizing vessel is provided as an additional silencer element 4, 4, ′, 4 ″, a motor pump generating negative pressure for the brake drive unit 1, 1 ′, 1 ″ of the automobile brake system. Assembly (3). The method of claim 9,
The further silencer element 4 ′ further comprises a Helmholtz resonator 8 which generates a negative pressure for the brake drive unit 1, 1 ′, 1 ″ of the motor vehicle brake system 3. . 11. The method of claim 10,
Said additional silencer element 4 "further has a capillary tube 9 which generates a negative pressure for the brake drive unit 1, 1 ′, 1 '' of the motor vehicle brake system 3. .

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