JP2006123798A - Brake system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the reliability of a brake system. <P>SOLUTION: The brake system is equipped with a negative pressure pump driven by an internal-combustion engine and supplying a negative pressure to a brake booster, a motor-driven negative pressure pump to supply negative pressure to the brake booster, and a control means to control the drive of the motor-driven negative pressure pump, wherein the control means drives the motor-driven negative pressure pump when the engine is in the driving condition and supplies a negative pressure to the brake booster. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a brake system with improved reliability.

2. Description of the Related Art Conventionally, a generator control device is known that includes a negative pressure pump driven by an engine and a generator that drives the negative pressure pump when the engine is stopped (see, for example, Patent Document 1). The negative pressure pump supplies negative pressure to the brake booster.
JP-A-10-236301

  However, in the above-described conventional generator control device, the generator is used for the generator when the engine is driven, and is used for driving the negative pressure pump when the engine is stopped. Become. In addition, when a failure occurs, there is a possibility that neither the power generation nor the negative pressure pump can function.

  The present invention has been made to solve such problems, and its main object is to improve the reliability of the brake system.

  One aspect of the present invention for achieving the above object is a negative pressure pump that is driven by an internal combustion engine to supply negative pressure to a brake booster, an electric negative pressure pump that supplies negative pressure to the brake booster, and the electric motor And a control means for controlling the driving of the negative pressure pump, wherein the control means drives the electric negative pressure pump to cause the brake booster to operate when the internal combustion engine is in a drive stop state. A brake system that supplies the negative pressure.

  In this embodiment, for example, supplying the negative pressure means introducing the negative pressure.

  According to this aspect, the control means drives the electric negative pressure pump to supply the negative pressure to the brake booster when the internal combustion engine is in a driving state. Thereby, the operation rate of the electric negative pressure pump can be reduced, and the load on the electric negative pressure pump can be reduced. Therefore, the failure rate of the electric negative pressure pump can be reduced, and the reliability of the brake system can be improved.

  Further, in this aspect, the apparatus further includes negative pressure detecting means for detecting a negative pressure level of the brake booster, and the control means is configured to detect the electric negative when the negative pressure level from the negative pressure detecting means is a predetermined value or less. A pressure pump may be driven to supply negative pressure to the brake booster. Thereby, a sufficient negative pressure can be supplied to the brake booster even in a continuous brake use state such as a pumping brake. Therefore, the brake system can be operated more reliably, and the reliability of the brake system is further improved.

  The negative pressure level being equal to or less than a predetermined value means that the absolute value of the negative pressure level is equal to or less than the absolute value of the predetermined value.

  Further, in this aspect, for example, the engine further includes a rotation speed detection means for detecting the rotation speed of the drive shaft of the internal combustion engine, and the control means is when the rotation speed of the drive shaft from the rotation speed detection means is zero. Then, it is determined that the internal combustion engine is in the drive stop state. When the rotational speed of the drive shaft from the rotational speed detection means is greater than 0, the negative pressure pump is driven to supply the negative pressure to the brake booster.

  One aspect of the present invention for achieving the above object is a vehicle speed detecting means for detecting a vehicle speed, a negative pressure pump driven by an internal combustion engine for supplying negative pressure to the brake booster, and supplying negative pressure to the brake booster. And a control means for controlling the negative pressure supplied by the electric negative pressure pump based on the vehicle speed from the vehicle speed detection means. When the vehicle speed from the vehicle speed detecting means is 0, the electric negative pressure pump is driven to supply the negative pressure to the brake booster.

  According to the present invention, the reliability of the brake system can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. Note that the basic concept, main hardware configuration, operating principle, basic control method, and the like of the vehicle brake system and the hybrid vehicle are known to those skilled in the art and will not be described in detail.

  FIG. 1 is a schematic diagram of a system configuration of a brake system according to an embodiment of the present invention. The brake system 1 according to this embodiment is mounted on a so-called hybrid vehicle that is driven by using, for example, an engine and an electric motor together.

  The brake system 1 according to this embodiment includes a brake booster (brake booster) 5 that assists the depressing force of the brake pedal 3 using the negative pressure supplied into the pressure chamber as a boost source. A negative pressure detecting means 7 such as a negative pressure sensor for detecting a negative pressure level in the pressure chamber of the brake booster 5 is attached to the brake booster 5. An electric negative pressure (vacuum) pump 11 is connected to the brake booster 5 via a negative pressure pipe 9, and the electric negative pressure pump 11 supplies negative pressure to the brake booster 5. In addition, the one-way valve 9a for allowing the fluid inside the pipe to flow only in one direction is attached to the negative pressure pipe 9. By this one-way valve 9a, negative pressure is accurately supplied from the electric negative pressure pump 11 to the brake booster 5.

  A power storage device 13 is connected to the electric negative pressure pump 11, and electric power is supplied from the power storage device 13 to the electric negative pressure pump 11. The power storage device 13 is connected to a generator motor 15 such as a three-phase dielectric motor. The generator motor 15 is connected to and driven by an internal combustion engine 21 such as an engine via a planetary gear mechanism 17 and a transmission 19 described later. The power storage device 13 includes a battery 13a and an inverter 13b. The electric power stored in the battery 13a is converted into an alternating current by the inverter 13b and supplied to the generator motor 15, and the generator motor 15 can be driven as an electric motor. Moreover, the electric power generated by driving the generator motor 15 as a generator is converted into a direct current by the inverter 13b and stored in the battery 13a.

  The planetary gear mechanism 17 rotates and revolves a sun gear as an external gear, a ring gear as an internal gear arranged concentrically with the sun gear, a plurality of pinion gears meshing with the sun gear and meshing with the ring gear, and a plurality of pinion gears. And a carrier that can be freely held. The sun gear, ring gear, and carrier that are the rotating elements are differential.

  A transmission (transmission) 19 is connected to the engine 21, and a propeller shaft 23 is connected to the transmission 19. The transmission 19 is an automatic transmission that is automatically controlled, and is configured to perform a shift shift optimum for vehicle travel based on a control signal from an ECU 25 described later. A drive shaft (drive shaft) 29 is connected to the propeller shaft 23 via a differential device 27, and a drive wheel 31 is connected to the drive shaft 29.

  A negative pressure pump 33 is connected to the transmission 19, and the negative pressure pump 33 is driven by the transmission 19. The negative pressure pump 33 is connected to the brake booster 5 via the negative pressure pipe 9 and supplies negative pressure to the brake booster 5. A one-way valve 9 a is attached to the negative pressure pipe 9.

  The electric negative pressure pump 11 is connected to a control means 25 such as an ECU for controlling the driving of the electric load pump 11. An ECU (Electronic Control Unit) 25 is constituted by a microcomputer, and has a ROM for storing a control program, a readable / writable RAM for storing calculation results, a timer, a counter, an input interface, and an output interface. .

  Further, the ECU 25 is connected to a rotation speed detecting means 35 such as a rotation sensor for detecting the rotation speed of the crankshaft of the engine 21.

  The ECU 25 controls the electric negative pressure pump 11 to be driven based on the rotational speed from the rotation sensor 35 and the negative pressure level from the negative pressure sensor 7 so that negative pressure is supplied to the brake booster.

  Next, a method for supplying negative pressure to the brake booster 5 will be described.

  When the engine is driven, the rotational force of the drive shaft of the engine 21 is transmitted to the drive shaft of the negative pressure pump 33 via the transmission 19, and the negative pressure pump 33 is driven. When the negative pressure pump 33 is driven, the negative pressure pump 33 supplies negative pressure to the pressure chamber of the brake booster 5 through the negative pressure pipe 9. The brake booster 5 assists the depression force of the brake pedal 3 using the supplied negative pressure as a boost source.

  FIG. 2 is a flowchart showing a control method in which the electric negative pressure pump 11 starts driving.

  As shown in FIG. 2, the ECU 25 determines whether or not the crankshaft rotation speed is 0 based on the rotation speed from the rotation sensor 35 (S100). When the ECU 25 determines that the rotation speed from the rotation sensor 35 is 0 (driving stop state), the ECU 25 transmits a driving start signal to the electric negative pressure pump 11 so as to start driving. The electric negative pressure pump 11 that has received the drive start signal starts driving and supplies negative pressure to the pressure chamber of the brake booster 5 via the negative pressure pipe 9 (S120). Further, it is assumed that the engine 21 is changed from the drive stop state to the drive state. In this case, when the ECU 25 determines that the rotation speed from the rotation sensor 35 is greater than 0, the ECU 25 transmits a drive stop signal to the electric negative pressure pump 11. The electric negative pressure pump 11 that has received the drive stop signal stops driving and stops supplying negative pressure to the pressure chamber of the brake booster 5. At this time, as described above, the negative pressure pump 33 is driven by the engine 21, and negative pressure is supplied from the negative pressure pump 33 to the brake booster 5.

Note that the hybrid vehicle according to the present embodiment is configured to automatically stop the engine during the light load region and when the vehicle is stopped for the purpose of improving fuel consumption and reducing CO ₂ .

  Further, the ECU 25 determines whether the negative pressure level in the pressure chamber of the brake booster 5 is equal to or lower than a predetermined value based on the negative pressure from the negative pressure sensor 7 (S110). When the ECU 25 determines that the negative pressure level from the negative pressure sensor 7 is below a predetermined value, the ECU 25 transmits a drive start signal to the electric negative pressure pump 11. The electric negative pressure pump 11 that has received the drive start signal starts driving and supplies negative pressure to the pressure chamber of the brake booster 5 via the negative pressure pipe 9 (S120). Thereby, a sufficient negative pressure can be supplied into the pressure chamber of the brake booster 5 even in a continuous brake use state such as a pumping brake. Therefore, the brake system 1 can be operated more reliably, and the reliability of the brake system 1 is further improved. In addition, the brake operation force is reduced, leading to an improvement in brake operability. In addition, as a case where the negative pressure level in the pressure chamber of the brake booster 5 becomes a predetermined value or less, for example, a state where the engine speed is low such as idle rotation, a state where an abnormality occurs in the negative pressure pump 33 or the negative pressure pipe 9, etc. Is mentioned.

  As described above, when the ECU 25 determines that the rotation speed from the rotation sensor 35 is 0 (driving stop state), the ECU 25 drives the electric negative pressure pump 11. Further, when the ECU 25 determines that the negative pressure level from the negative pressure sensor 7 is not more than a predetermined value, the ECU 25 drives the electric negative pressure pump 11. Thereby, the operation rate of the electric negative pressure pump 11 can be reduced, and the load on the electric negative pressure pump 11 can be reduced. Therefore, the failure rate of the electric negative pressure pump 11 can be reduced, leading to improved reliability. In addition, the brake system 1 according to this embodiment does not need to always drive the electric negative pressure pump 11 as compared with the case where the electric negative pressure pump 11 is always driven as in the conventional brake system. Durability specifications can be satisfied without using a highly durable electric negative pressure pump. In general, since the electric negative pressure pump with good operation durability is expensive, the cost of the electric negative pressure pump 11 can be reduced, leading to a reduction in vehicle manufacturing cost.

  Furthermore, since the decrease in the amount of power stored in the power storage device 13 can be suppressed, for example, when the brake system 1 is mounted on a hybrid vehicle, the actual travel distance of the hybrid vehicle can be improved.

  As mentioned above, although the best mode for carrying out the present invention has been described using one embodiment, the present invention is not limited to such one embodiment, and within the scope not departing from the gist of the present invention, Various modifications and substitutions can be made to the above-described embodiment.

  For example, in the above embodiment, the negative pressure pump 33 is connected to the transmission 19 and the negative pressure pump 33 is driven by the transmission 19. However, the negative pressure pump 33 is connected to the propeller shaft 23, and the negative pressure pump 33. May be driven by a propeller shaft 23. Further, the negative pressure pump 33 may be connected to the planetary gear mechanism 17, the differential device 27, or the crankshaft, and the negative pressure pump 33 may be driven by the planetary gear mechanism 17, the differential device 27, or the crankshaft.

  In the above embodiment, a negative pressure tank may be provided between the negative pressure pump 33 and the electric negative pressure pump 11 and the brake booster 5. In this case, the negative pressure supplied from the negative pressure pump 33 and the electric negative pressure pump 11 is once accumulated in the negative pressure tank, and the negative pressure is stably supplied from the negative pressure tank to the brake booster 5. Therefore, the reliability of the brake system 1 is improved.

  Furthermore, in (S100) of the above embodiment, the ECU 25 determines whether or not the crankshaft rotation speed is 0 based on the rotation speed from the rotation sensor 35. And the drive of the electric negative pressure pump 11 may be controlled based on the vehicle speed from the vehicle speed sensor. Specifically, when the vehicle speed from the vehicle speed sensor is 0, the ECU 25 may drive the electric negative pressure pump 11 and supply negative pressure to the brake booster 5. Further, when the vehicle speed from the vehicle speed sensor is equal to or lower than a predetermined value, the ECU 25 may drive the electric negative pressure pump 11 to supply negative pressure to the brake booster 5.

  In the above embodiment, the ECU 25 may drive the electric negative pressure pump 11 and supply the negative pressure to the brake booster 5 based on the amount of power stored in the battery 13 a of the power storage device 13. For example, the power storage device 13 has a battery control unit that monitors and manages the power storage amount and the discharge amount, and the ECU 25 drives the electric negative pressure pump 11 based on the power storage amount of the battery 13a from the battery control unit, so that the brake booster 5 may be supplied with negative pressure. Specifically, the ECU 25 may not drive the electric negative pressure pump 11 without transmitting a drive start signal to the electric negative pressure pump 11 when the storage amount of the battery 13a is equal to or less than a predetermined value. Note that the battery control unit calculates the amount of charge (remaining capacity) based on the integrated value of the charge / discharge current from the current sensor provided in the battery 13a and the inter-terminal voltage from the voltage sensor.

  In the above embodiment, the ECU 25 may perform only the processes (S100) and (S120), or may perform the processes only (S110) and (S120).

  In the above embodiment, negative pressure is supplied to the brake booster 5 by the negative pressure pump 33 driven by the engine 21, but negative pressure generated in the intake pipe of the engine 21 may be supplied to the brake booster 5. . Specifically, the intake pipe of the engine 21 may be connected to the brake booster 5 via the negative pressure pipe 9 and the one-way valve 9a. In this case, if the throttle opening of the engine 21 is decreased, the negative pressure level in the intake pipe increases, and the negative pressure supplied to the brake booster 5 increases.

  In the above embodiment, the ECU 25 may determine whether or not the engine 21 is in a driving state based on a flow rate from an air flow meter (air flow sensor) attached to the intake pipe. Specifically, the ECU 25 may determine that the engine 21 is in a driving state when the flow rate from the air flow meter is equal to or greater than a predetermined value.

  In the above embodiment, the brake system according to an embodiment of the present invention is applied to a hybrid vehicle that is driven by using the engine 21 and the electric motor (generator motor) 15 together. The present invention can also be applied to a vehicle or a so-called eco-run vehicle.

  The present invention can be used for a brake system for a vehicle. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited.

It is the schematic of the system configuration | structure of the brake system which concerns on one Example of this invention. It is a flowchart which shows the control method which an electric negative pressure pump starts a drive.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake system 3 Brake pedal 5 Brake booster 7 Negative pressure sensor (negative pressure detection means)
11 Electric negative pressure pump 19 Transmission 21 Engine (internal combustion engine)
23 Propeller shaft 25 ECU (control means)
33 Negative pressure pump 35 Rotation sensor (Rotation speed detection means)

Claims (5)

A negative pressure pump driven by an internal combustion engine to supply negative pressure to the brake booster;
An electric negative pressure pump for supplying negative pressure to the brake booster;
A brake system comprising: control means for controlling the drive of the electric negative pressure pump,
The control system drives the electric negative pressure pump to supply the negative pressure to the brake booster when the internal combustion engine is in a drive stop state. The brake system according to claim 1,
A negative pressure detecting means for detecting a negative pressure level of the brake booster;
When the negative pressure level from the negative pressure detecting means is below a predetermined value, the control means drives the electric negative pressure pump to supply negative pressure to the brake booster. The brake system according to claim 1 or 2,
A rotation speed detecting means for detecting the rotation speed of the drive shaft of the internal combustion engine;
The brake system according to claim 1, wherein the control means determines that the internal combustion engine is in the drive stop state when the rotational speed of the drive shaft from the rotational speed detection means is zero. The brake system according to claim 3, wherein
The brake system according to claim 1, wherein when the rotational speed of the drive shaft from the rotational speed detection means is greater than 0, the negative pressure pump is driven to supply the negative pressure to the brake booster. Vehicle speed detection means for detecting the vehicle speed;
A negative pressure pump driven by an internal combustion engine to supply negative pressure to the brake booster;
An electric negative pressure pump for supplying negative pressure to the brake booster;
Control means for controlling the negative pressure supplied by the electric negative pressure pump based on the vehicle speed from the vehicle speed detection means, and a brake system comprising:
When the vehicle speed from the vehicle speed detection means is 0, the control means drives the electric negative pressure pump to supply the negative pressure to the brake booster.

Images