JP2006137286A - Brake system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of a brake system. <P>SOLUTION: This brake system is provided with a vacuum pump driven by an internal combustion engine to supply negative pressure through piping to a brake booster, and an electric vacuum pump connected to the piping to supply negative pressure through the piping to the brake booster. It is also provided with a blocking means to block flow in the piping, and a control means to control the blocking by the blocking means. The control means controls the blocking means to block flow in the piping when the internal combustion engine is in a drive stop state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

Conventionally, a negative pressure operating device that operates using a negative pressure as a driving source, a vacuum pump that is driven by an engine to generate negative pressure, an abnormality determination means that determines whether a vacuum pump is abnormal, and a throttle valve opening control There is known an automotive negative pressure supply system including an opening degree control means, and a negative pressure supply path switching means for switching a negative pressure from a vacuum pump and a negative pressure from an intake passage (for example, Patent Document 1). Further, negative pressure is supplied to the negative pressure operating device from a vacuum pump and an intake passage through a pipe.
Japanese Patent Laid-Open No. 10-54286

  However, in the above conventional negative pressure supply system for automobiles, when the engine is stopped, the lubricating oil in the vacuum pump is sucked into the pipe due to the negative pressure in the negative pressure operating device, and the negative pressure operating device There is a risk of malfunction.

  Further, even when a one-way valve is arranged in the pipe, it is difficult to prevent the lubricating oil from flowing into the negative pressure operating device if the one-way valve fails in an open state.

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

  In one aspect of the present invention for achieving the above object, a vacuum pump that is driven by an internal combustion engine and supplies a negative pressure to a brake booster via a pipe, is connected to the pipe, and is connected to the brake booster via the pipe. An electric vacuum pump for supplying negative pressure to the brake system, comprising: a shut-off means for shutting off the flow in the pipe; and a control means for controlling the shut-off of the shut-off means. The brake system is characterized in that when the internal combustion engine is in a drive stop state, the blocking means is controlled so as to block the flow in the pipe.

  In this aspect, for example, supplying a negative pressure means introducing a negative pressure. The shut-off means is, for example, an electromagnetic valve such as a solenoid valve.

  According to this aspect, the control means controls the shut-off means so as to shut off the flow in the pipe when the internal combustion engine is in a drive stop state. As a result, when the internal combustion engine is stopped and the vacuum pump is stopped, the lubricating oil flowing into the pipe from the vacuum pump can be blocked by the blocking means. Therefore, it is possible to reliably prevent the lubricating oil from flowing into the electric vacuum pump. That is, the cause of failure of the electric vacuum pump can be reliably reduced, and the reliability of the brake system can be improved. Further, when the internal combustion engine is stopped and the vacuum pump is stopped, the air flowing into the pipe via the vacuum pump can be reliably blocked by the blocking means. Therefore, the pressure loss of the negative pressure supplied from the electric vacuum pump to the brake booster can be reduced. That is, the pump efficiency of the electric vacuum pump can be improved, leading to energy saving of the electric vacuum pump and further energy saving of the entire vehicle. In addition, since the negative pressure can be stably supplied to the brake booster by the electric vacuum pump, the depressing force of the brake pedal is reduced and the brake operability is improved.

  Further, in this one aspect, for example, a rotation speed detection means for detecting the rotation speed of the drive shaft of the internal combustion engine is further provided, and the control means is configured such that when the rotation speed of the drive shaft is 0 from the rotation speed detection means, It may be determined that the internal combustion engine is in the drive stop state, and the flow in the first pipe may be shut off.

  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. The basic concept, main hardware configuration, operating principle, basic control method, and the like of the vehicle brake system are known to those skilled in the art, and thus detailed description thereof is omitted.

  FIG. 1 is a system configuration diagram of a brake system according to an embodiment of the present invention. 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 vacuum (negative pressure) pump 9 is connected to the brake booster 5 via a first pipe 7. The vacuum pump 9 is connected and driven to an internal combustion engine 11 such as an engine, and supplies negative pressure to the brake booster 5 via the first pipe 7. A mechanical first check valve (one-way valve) 13 that allows the fluid inside the pipe to flow only in one direction is disposed near one end of the first pipe 7 connected to the vacuum pump 9. Further, a negative pressure sensor 15 and a second check valve 17 are arranged in this order from the brake booster 5 side in the vicinity of the other end of the first pipe 7 connected to the brake booster 5. The negative pressure sensor 15 detects the negative pressure supplied into the pressure chamber of the brake booster 5. The negative pressure sensor 15 is connected to an ECU 19 described later.

  One end of the second pipe 21 is connected between the first check valve 13 and the second check valve 17 of the first pipe 7 at a position near the brake booster 5. An electric vacuum pump 23 is connected to the other end of the second pipe 21, and a third check valve 25 is disposed near the other end. The electric vacuum pump 23 supplies negative pressure to the brake booster 5 via the second pipe 21.

  The first check valve 13, the second check valve 17, and the third check valve 25 are mechanical opening / closing mechanisms and can be opened / closed only in one direction. That is, the first check valve 13 is configured to be opened only when the negative pressure level on the vacuum pump 9 side is higher than the negative pressure level on the brake booster 5 side. The second check valve 17 is configured to be opened only when the negative pressure level on the electric vacuum pump 23 side is higher than the negative pressure level on the brake booster 5 side. Further, the third check valve 25 is configured to be opened only when the negative pressure level on the vacuum pump 9 side and the electric vacuum pump 23 side is higher than the negative pressure level on the brake booster 5 side. The first check valve 13 and the second check valve 17 are opened only when the negative pressure is supplied by the vacuum pump 9 configured as described above. Further, only when the negative pressure is supplied from the electric vacuum pump 23, the second check valve 17 and the third check valve 25 are opened. Thereby, a negative pressure can be more reliably confined in the pressure chamber of the brake booster 5.

  A blocking means 27 such as an electromagnetic valve for blocking the flow in the first pipe 7 is disposed between the first check valve 13 and the second check valve 17 of the first pipe 7 at a position near the vacuum pump 9. . The electromagnetic valve 27 is connected to a control means 19 such as an ECU (Electronic Control Unit). When the electromagnetic valve 27 receives a closing signal from the ECU 19, the electromagnetic valve 27 is in a closed state and blocks the flow of fluid in the first pipe 7. Further, when the electromagnetic valve 27 receives an open signal from the ECU 19, the electromagnetic valve 27 is in an open state and allows the fluid in the first pipe 7 to flow.

  The ECU 19 is connected to a rotation speed detection means 29 such as a rotation sensor that detects the rotation speed of a drive shaft such as a crankshaft of the engine 11. The ECU 19 transmits an open signal and a close signal to the electromagnetic valve 27 based on the rotation speed from the rotation sensor 29.

  The ECU 19 is configured by a microcomputer, and includes a ROM that stores a control program, a readable / writable RAM that stores calculation results, a timer, a counter, an input interface, and an output interface.

  The electric vacuum pump 23 is connected to the ECU 19, and the electric vacuum pump 23 starts to be driven by a drive start signal from the ECU 19 and stops to be driven by a drive stop signal. For example, the ECU 19 transmits a drive start signal to the electric vacuum pump 23 when the rotation speed from the rotation sensor 29 is 0 (engine stop state). Further, the ECU 19 transmits a drive stop signal to the electric vacuum pump 23 when the rotation speed from the rotation sensor 29 is larger than 0 (engine drive state). As a result, the negative pressure is reliably supplied to the brake booster 5 by the electric vacuum pump 23 even when the negative pressure is not supplied from the vacuum pump 9 when the engine 11 is stopped.

  Next, control processing of the electromagnetic valve 27 of the brake system 1 according to the present embodiment will be described.

  FIG. 2 is a flowchart showing a routine of control processing of the electromagnetic valve 27 of the brake system 1 according to this embodiment. This routine is repeatedly executed every predetermined minute time.

  The ECU 19 determines whether or not the rotation speed from the rotation sensor 29 is 0 (S100). When the ECU 19 determines that the rotation speed from the rotation sensor 29 is 0 (engine drive stopped state), the ECU 19 transmits a close signal to the electromagnetic valve 27. When the solenoid valve 27 receives the close signal, the solenoid valve 27 is closed and shuts off the flow of fluid such as air in the first pipe 7 (S120).

  On the other hand, when the ECU 19 determines that the rotation speed from the rotation sensor 29 is not 0 (engine drive state), the ECU 19 transmits an open signal to the electromagnetic valve 27. When the electromagnetic valve 27 receives the open signal, the electromagnetic valve 27 is in an open state, and allows a fluid such as air in the first pipe 7 to flow (S110).

  For example, it is assumed that the first check valve 13 and the second check valve 17 are fixed in an open state due to a failure in an engine stop state (open failure). In the conventional brake system, since the vacuum pump 9 does not supply negative pressure, the lubricating oil in the vacuum pump 9 flows into the first pipe 7 due to the negative pressure of the brake booster 5. Further, the lubricating oil that has flowed out may pass through the first check valve 13 and the second check valve 17 and flow into the brake booster 5. Further, when the third check valve 25 fails in the open state, the lubricating oil that has flowed into the first pipe 7 due to the negative pressure of the electric vacuum pump 23 passes through the second pipe 21 and the third check valve 25 and is electrically driven. There is a risk of flowing into the vacuum pump 23. Due to the inflow of the lubricating oil, the brake booster 5 and the electric vacuum pump 23 may break down. The brake system 1 according to this embodiment blocks the flow of the lubricating oil in the first pipe 7 by the electromagnetic valve 27 (S120), and ensures that the lubricating oil flows into the brake booster 5 and the electric vacuum pump 23. Can be prevented. As a result, the possibility of failure of the brake booster 5 and the electric vacuum pump 23 can be reliably reduced, and the reliability of the brake system 1 can be improved.

  Similarly, for example, a case is assumed in which the first check valve 13 is fixed in an open state due to a failure in an engine drive stop state. In the conventional brake system, since the vacuum pump 9 does not supply negative pressure, air flows into the first pipe 7 by the negative pressure of the brake booster 5 and the electric vacuum pump 23. The air that has flowed in passes through the first check valve 13 and the second pipe 21 and flows into the electric vacuum pump 23. As a result, the pump efficiency of the electric vacuum pump 23 decreases. The brake system 1 according to this embodiment cuts off the flow of air in the first pipe 7 by the electromagnetic valve 27 (S120), and ensures that the air flowing from the vacuum pump 9 through the first check valve 13 flows. Can be blocked. Therefore, the pressure loss of the negative pressure supplied from the electric vacuum pump 23 to the brake booster 5 can be reduced. That is, the pump efficiency of the electric vacuum pump 23 can be improved, leading to energy saving of the electric vacuum pump 23 and further energy saving of the entire vehicle. Further, since the negative pressure can be stably supplied to the brake booster 5 by the electric vacuum pump 23, the depressing force of the brake pedal 3 is reduced, and the brake operability is improved. Note that the case where the check valves 13, 17, 25 are fixed in an open state due to the above failure includes, for example, a case where a seat failure of the check valves 13, 17, 25 occurs due to deterioration over time.

By the way, the hybrid vehicle driven by using the engine 11 and the electric motor together is configured to automatically stop the engine 11 during the light load region and when the vehicle is stopped for the purpose of improving fuel consumption and reducing CO ₂ . The eco-run vehicle is configured to automatically stop the engine when the engine is in an idling state for the purpose of improving fuel consumption and reducing CO ₂ . The brake system 1 according to this embodiment is particularly effective when mounted on a hybrid vehicle and an eco-run vehicle that frequently drive and stop the engine 11. Needless to say, the brake system 1 according to the present embodiment is effective even when mounted on a vehicle other than the hybrid vehicle and the eco-run vehicle.

  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, one electromagnetic valve 27 is arranged in the first pipe 7, but the number of arranged electromagnetic valves 27 may be two or more, or arranged in the second pipe 21. May be. If the number of arranged electromagnetic valves 27 is increased, the lubricating oil and air flowing into the first pipe 7 can be more reliably shut off.

  In the above embodiment, the first pipe 7 is provided with the two check valves 13 and 17, and the second pipe 21 is provided with the one check valve 25. The number of check valves provided in the pipe 21 may be arbitrary.

  Further, in the above embodiment, the negative pressure is supplied to the brake booster 5 by the vacuum pump 9, but the negative pressure may be supplied to the brake booster 5 by intake of the engine 11. In this case, even when the first check valve 13 has an open failure, the electromagnetic valve 27 can be shut off to reliably shut off the air flowing into the first pipe 7 through the first check valve 13. .

  In the above embodiment, a negative pressure tank may be provided between the second check valve 17 and the brake booster 5. In this case, the negative pressure supplied from the vacuum pump 9 and the electric vacuum pump 23 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.

  The present invention can be used for a brake system employed in a hybrid vehicle and an eco-run vehicle. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited.

It is a system configuration figure of a brake system concerning one example of the present invention. It is a flowchart which shows the routine of the control process of the solenoid valve of the brake system which concerns on a present Example.

Explanation of symbols

1 Brake System 3 Brake Pedal 5 Brake Booster 7 First Piping (Piping)
9 Vacuum pump 11 Engine (Internal combustion engine)
13 First check valve 15 Negative pressure sensor 17 Second check valve 19 ECU (control means)
21 Second piping (piping)
23 Electric vacuum pump 25 Third check valve 27 Solenoid valve (blocking means)
29 Rotation sensor (Rotation speed detection means)

Claims (2)

A brake that is driven by an internal combustion engine and that supplies a negative pressure to a brake booster via a pipe, and an electric vacuum pump that is connected to the pipe and supplies a negative pressure to the brake booster via the pipe A system,
Blocking means for blocking the flow in the pipe;
Control means for controlling the shut-off of the shut-off means,
The brake system according to claim 1, wherein the control means controls the shut-off means so as to shut off the flow in the pipe when the internal combustion engine is in a drive stop state. The brake system according to claim 1,
A rotation speed detecting means for detecting the rotation speed of the drive shaft of the internal combustion engine;
The control means determines that the internal combustion engine is in the drive stop state when the rotational speed of the drive shaft is 0 from the rotational speed detection means, and blocks the flow in the pipe. system.

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