JP2007210453A - Vehicular vacuum pump system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conduct the assist of brake pedal operation which suppresses a drive loss of an engine and suppresses the worsening of riding comfort in a vehicle cabin. <P>SOLUTION: A lower arm 14 supports a wheel in a vacuum pump system 10. An upper vehicle body 24 supports the vehicle cabin and is supported by the lower arm 14 through a suspension 20. A first vacuum pump 15 generates negative pressure by using the variation of the relative position of the lower arm 14 and the upper vehicle body 24. A variable damping force absorber 22 varies damping forces which are applied to the lower arm 14 and the upper vehicle body 24, respictively. An ECU100 suppresses the vibration of the upper vehicle body 24 by controlling the variable damping force absorber 22 to vary the damping force in accordance with the forces which are applied to the lower arm 14 and the upper vehicle body 24, respictively, when the first vacuum pump 15 operates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle vacuum pump system, for example, a vehicle vacuum pump system used for generating negative pressure of a brake booster.

  A brake booster is known as a device that assists the pedaling force of a brake pedal. The brake booster has a negative pressure chamber inside, and assists the depression force of the brake pedal by utilizing the difference between the negative pressure in the negative pressure chamber and the atmospheric pressure. A vacuum pump is widely used as a negative pressure source for the brake booster. As a method including such a vacuum pump, for example, Patent Document 1 includes a mechanically driven vacuum pump driven by a crankshaft and an electric vacuum pump driven by a battery, and the negative pressure is a constant pressure higher than a set pressure. There has been proposed a hydraulic braking device for an automobile that drives an electric vacuum pump in the case of the above. Further, for example, in Patent Document 2, a negative pressure supply device for a negative pressure operation type brake booster connected to a negative pressure port of an intake system of an engine with an engine automatic stop device, the number of times of operation of the brake during the engine automatic stop There has been proposed a negative pressure supply device for a brake booster that detects and detects that the number of times exceeds a set value and drives an electric vacuum pump for a predetermined time.

The mechanically driven vacuum pump driven by the crankshaft generates engine drive loss when driven. Since the electric vacuum pump uses electric power generated using the driving force of the engine, engine driving loss still occurs. In order to suppress such engine drive loss, for example, in Patent Document 3, the negative pressure of the brake booster is changed by changing the volume of the space formed between the piston and the casing by the vibration of the vehicle during traveling. A vacuum pump for a vehicle that generates the above has been proposed.
Japanese Utility Model Publication No. 63-202561 JP 59-164252 A JP 2000-257554 A

  However, since the technique described in Patent Document 3 generates a negative pressure due to vibration of the vehicle, there is a possibility that a reaction force from the cylinder or the piston is transmitted to the vehicle cabin. Since the reaction force due to the cylinder or piston changes according to the generated negative pressure, it is difficult to adopt a suspension that takes such reaction force into consideration in advance.

  The present invention has been made in view of these problems, and an object of the present invention is to realize an assist of a brake pedal operation that suppresses engine drive loss and to suppress a deterioration in riding comfort in a vehicle cabin.

  In order to solve the above-described problems, a vehicle vacuum pump system according to an aspect of the present invention includes a first support portion that supports wheels, and a first support portion that supports a vehicle cabin and is supported by the first support portion via a suspension. A vacuum pump that generates a negative pressure using a change in position relative to the two support portions, and a force that interacts with the first support portion and the second support portion when the vacuum pump is operated. And a vibration control unit that suppresses the vibration of the second support unit.

  According to this aspect, even when the force acting on the first support portion and the second support portion varies due to the operation of the vacuum pump, the vibration of the second support portion can be suppressed. It becomes. For this reason, the vibration transmitted to the vehicle cabin can be suppressed, and the deterioration of the riding comfort in the vehicle cabin due to the provision of the vacuum pump can be suppressed.

  The vibration control unit includes a damping force variable unit that changes a damping force that interacts with the first support unit and the second support unit, and the first support unit and the second support unit when the vacuum pump operates. And an absorber control unit that controls the variable damping force unit so as to change the damping force according to the force acting on the support unit. According to this aspect, by adopting a simple configuration in which the damping force variable unit is provided, it is possible to suppress deterioration in riding comfort in the vehicle cabin.

  The vehicle vacuum pump system according to this aspect may further include a negative pressure sensor that detects the negative pressure of the brake booster. The vibration control unit may suppress the vibration of the second support unit according to the detected negative pressure of the brake booster. The force that interacts with the first support portion and the second support portion when the vacuum pump is operated varies depending on the negative pressure of the brake booster. According to this aspect, it is possible to suppress the deterioration of the riding comfort in the vehicle cabin by a simple configuration of detecting the negative pressure generated by the vacuum pump.

  The vehicle vacuum pump system according to this aspect may further include a negative pressure sensor that detects a negative pressure of the vacuum pump. The vibration control unit may suppress vibration of the second support unit according to the detected negative pressure of the vacuum pump. The force that interacts with the first support portion and the second support portion when the vacuum pump is operated varies depending on the negative pressure of the brake booster. According to this aspect, it is possible to suppress the deterioration of the riding comfort in the vehicle cabin by a simple configuration of detecting the negative pressure generated by the vacuum pump.

  According to the vehicle vacuum pump system of the present invention, it is possible to realize the assist of the brake pedal operation while suppressing the drive loss of the engine, and to suppress the deterioration of the riding comfort in the vehicle cabin.

  Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a vacuum pump system 10 according to the present embodiment. The vacuum pump system 10 includes a brake pedal 42, a brake booster 40, a negative pressure sensor 44, a pump motor 36, a second vacuum pump 38, a vacuum tank 30, a first vacuum pump 15, a damping force variable absorber 22, an electronic control unit (hereinafter referred to as an electronic control unit). 100 (referred to as “ECU”).

  The brake pedal 42 is connected to the brake booster 40 via an operating rod. The brake booster 40 is connected to a master cylinder (not shown) on the side opposite to the side connected to the operating rod. The brake booster 40 has a booster cylinder (not shown) and a booster piston (not shown). A cylindrical cylinder chamber having a short axial length with respect to the diameter is formed inside the booster cylinder. The brake piston is formed in a disc shape having an outer diameter substantially the same as the inner diameter of the cylinder chamber. The booster piston is fitted into the cylinder chamber of the brake cylinder so as to be slidable in the axial direction.

  The brake piston is fitted into the cylinder chamber of the brake cylinder, so that the cylinder chamber, the operating rod side variable pressure chamber and the master cylinder side constant pressure chamber are separated. In a state before the brake pedal is operated, the constant pressure chamber and the variable pressure chamber communicate with each other. Negative pressure is supplied to the constant pressure chamber from a first vacuum pump and a second vacuum pump, which will be described later. For this reason, substantially the same negative pressure is given to the pressure in the constant pressure chamber and the pressure in the variable pressure chamber. When the brake pedal is operated by the driver, communication between the constant pressure chamber and the variable pressure chamber is blocked, and atmospheric pressure is introduced into the variable pressure chamber. As a result, the pressure in the variable pressure chamber becomes higher than the pressure in the constant pressure chamber, and the brake piston is given a force in the direction toward the constant pressure chamber. This force pushes the piston rod (not shown), and pressurizes the master cylinder. Thus, the brake booster 40 assists the driver's operation of the brake pedal 42.

  A vacuum tank 30 is connected to the constant pressure chamber of the brake booster 40 via a third check valve 32. The third check valve 32 opens when the negative pressure of the vacuum tank 30 is equal to or higher than a predetermined value, and supplies the negative pressure of the vacuum tank 30 to the brake booster 40. The third check valve 32 is closed when the negative pressure of the vacuum tank 30 is smaller than a predetermined value, and prevents the negative pressure from flowing from the brake booster 40 to the vacuum tank 30.

  The vacuum tank 30 is connected to the first vacuum pump 15 via the second check valve 28 on the side opposite to the side connected to the brake booster 40. The second check valve 28 opens when the negative pressure of the first vacuum pump 15 is equal to or higher than a predetermined value, and supplies the negative pressure of the first vacuum pump 15 to the vacuum tank 30. The second check valve 28 is closed when the negative pressure of the first vacuum pump 15 is smaller than a predetermined value, and prevents the negative pressure from flowing from the vacuum tank 30 to the first vacuum pump 15.

  The first vacuum pump 15 has a cylinder 18 and a piston 16. The cylinder 18 has a cylinder chamber which is a space formed in a columnar shape. The piston 16 is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the cylinder chamber. The piston 16 is fitted into the cylinder chamber of the cylinder 18 so as to be slidable in the axial direction. The cylinder chamber of the cylinder 18 is connected to the atmosphere via the first check valve 26. The first check valve 26 discharges air in the cylinder chamber to the atmosphere when the pressure in the cylinder chamber of the cylinder 18 exceeds a predetermined value. Further, when the pressure in the cylinder chamber becomes smaller than a predetermined value, the inflow of air from the atmosphere to the cylinder chamber is prevented.

  The wheel 12 is rotatably supported by a lower arm 14 as a first support portion. The lower arm 14 supports an upper vehicle body 24 as a second support portion via the suspension 20. The upper vehicle body 24 supports a vehicle cabin (not shown). By supporting the upper vehicle body 24 on the lower arm 14 via the suspension 20, when the road surface is uneven while the vehicle is running, the relative position change between the lower arm 14 and the upper vehicle body 24 can be appropriately given. Thus, the transmission of the vertical vibration of the wheel 12 to the upper vehicle body 24 is suppressed. As a result, the deterioration of the ride comfort of the user in the vehicle cabin due to the road surface condition while the vehicle is running is suppressed.

  The piston 16 is fixed to the lower arm 14 so as to move in the vertical direction together with the lower arm 14. The cylinder 18 is fixed to the upper vehicle body 24 so as to move in the vertical direction together with the upper vehicle body 24. For this reason, the piston 16 slides in the cylinder chamber of the cylinder 18 due to a change in the relative position of the lower arm 14 and the upper vehicle body 24 when the road surface is uneven during vehicle travel.

  When the relative positions of the lower arm 14 and the upper vehicle body 24 change in the direction in which the relative distance is shortened, the piston 16 slides in the cylinder chamber in the direction in which the air in the cylinder chamber of the cylinder 18 is compressed. . When the air in the cylinder chamber is compressed, the negative pressure in the cylinder chamber decreases. When the negative pressure in the cylinder chamber decreases to a negative pressure smaller than a predetermined value, the second check valve 28 is closed, and the supply of the negative pressure from the first vacuum pump 15 to the vacuum tank 30 is blocked. Further, when the piston 16 slides and the air in the cylinder chamber is compressed and the pressure in the cylinder chamber exceeds a predetermined value, the first check valve 26 is opened, and the air in the cylinder chamber is discharged into the atmosphere. The

  When the relative position between the lower arm 14 and the upper vehicle body 24 increases in the direction in which the relative distance increases, the piston 16 slides in the cylinder chamber in the direction in which the air in the cylinder chamber of the cylinder 18 is expanded. . When the air in the cylinder chamber expands, the pressure in the cylinder chamber decreases and the negative pressure increases. When the pressure in the cylinder chamber decreases to a value smaller than a predetermined value, the first check valve 26 is closed, and the outflow of air from the cylinder chamber to the atmosphere is prevented. Further, when the piston 16 slides and the air in the cylinder chamber expands and the negative pressure in the cylinder chamber exceeds a predetermined value, the second check valve 28 opens, and the negative pressure in the cylinder chamber is reduced to the vacuum tank 30. To be supplied.

  As described above, the first vacuum pump 15 generates a negative pressure by using a change in relative position between the lower arm 14 and the upper vehicle body 24. This makes it possible to supply negative pressure to the brake booster 40 while suppressing engine drive loss as compared to a mechanically driven vacuum pump driven by a crankshaft.

  The constant pressure chamber of the brake booster 40 is connected to the second vacuum pump 38 via the fourth check valve 34. The second vacuum pump 38 opens when the negative pressure of the second vacuum pump 38 is equal to or higher than a predetermined value, and supplies the negative pressure generated by the second vacuum pump 38 to the brake booster 40. The fourth check valve 34 is closed when the negative pressure of the second vacuum pump 38 is smaller than a predetermined value, and prevents the negative pressure from flowing from the brake booster 40 to the second vacuum pump 38. The second vacuum pump 38 is driven by a pump motor 36. The pump motor 36 is connected to an ECU 100 provided inside the vehicle body.

  A negative pressure sensor 44 is provided in the constant pressure chamber of the brake booster 40. The negative pressure sensor 44 detects the negative pressure in the constant pressure chamber of the brake booster 40. Hereinafter, the negative pressure of the brake booster 40 will be described as the negative pressure in the constant pressure chamber of the brake booster 40. The negative pressure sensor 44 is connected to the ECU 100.

  The ECU 100 determines from the detection result input from the negative pressure sensor 44 whether or not the negative pressure of the brake booster 40 is lower than a predetermined value. When it is determined that the negative pressure of the brake booster 40 is low, the ECU 100 supplies current to the pump motor 36 to operate the pump motor 36. As a result, the second vacuum pump 38 is driven and negative pressure is supplied to the brake booster 40. When the ECU 100 determines that the negative pressure of the brake booster 40 has increased to a predetermined value, the ECU 100 stops the supply of electric power to the pump motor 36 and stops the supply of negative pressure to the brake booster 40. Therefore, the second vacuum pump 38 functions as an electric vacuum pump that supplies negative pressure to the brake booster 40 with electric power. The ECU 100 also functions as a negative pressure control unit that controls the negative pressure of the brake booster 40.

  The first vacuum pump 15 can sufficiently supply a negative pressure to the brake booster 40 when the road surface has a certain degree of unevenness while the vehicle is running. However, it is difficult for the first vacuum pump 15 to generate a sufficient negative pressure when the vehicle is stopped or when traveling on a road surface with less unevenness. By providing the second vacuum pump 38 in this way, it is possible to reliably supply the negative pressure to the brake booster 40 even when it is difficult to generate the negative pressure by the first vacuum pump 15.

  However, when the first vacuum pump 15 is operated, a force acts between the lower arm 14 and the upper vehicle body 24. For example, when the piston 16 slides in the cylinder chamber in the direction in which the air in the cylinder chamber is compressed, a force acts on the lower arm 14 and the upper vehicle body 24 in directions away from each other. Further, when the piston 16 slides in the cylinder chamber in the direction in which the air in the cylinder chamber is expanded, a force acts on the lower arm 14 and the upper vehicle body 24 in a direction approaching each other.

  Thus, the force that interacts with the lower arm 14 and the upper vehicle body 24 changes depending on the negative pressure of the brake booster 40. For example, when the negative pressure value of the brake booster 40 is not high and the piston 16 slides in the cylinder chamber in the direction of expanding the air in the cylinder chamber, the air is supplied from the constant pressure chamber of the brake booster 40 to the first vacuum pump 15. As a result, the negative pressure is supplied to the constant pressure chamber of the brake booster 40. For this reason, the force acting in the direction in which the lower arm 14 and the upper vehicle body 24 approach each other is weakened. On the other hand, when the piston 16 slides in the cylinder chamber in the direction in which the air in the cylinder chamber expands when the negative pressure of the brake booster 40 is sufficiently high, supply of the negative pressure from the first vacuum pump 15 to the brake booster 40 is performed. And the discharge of air from the constant pressure chamber of the brake booster 40 to the first vacuum pump 15 is suppressed. For this reason, the force which acts in the direction in which the lower arm 14 and the upper vehicle body 24 approach each other becomes strong.

  Thus, in order to cope with the force that interacts with the lower arm 14 and the upper vehicle body 24, which changes depending on the operating state of the first vacuum pump 15, the vacuum pump system 10 according to the present embodiment has a damping force variable unit. A force variable absorber 22 is provided. The damping force variable absorber 22 is juxtaposed with the suspension 20, and both ends thereof are connected to the lower arm 14 and the upper vehicle body 24. The damping force variable absorber 22 adjusts the damping force that interacts with the lower arm 14 and the upper vehicle body 24 by changing the diameter of the internal oil valve or the rigidity of the valve. The damping force variable absorber 22 changes the damping force acting on the lower arm 14 and the upper vehicle body 24 by the expansion and contraction of the suspension 20 and the operation of the piston 16 in the first vacuum pump 15.

  The damping force variable absorber 22 is connected to the ECU 100 provided inside the vehicle body. The ECU 100 estimates the force acting on the lower arm 14 and the upper vehicle body 24 using the detection result of the negative pressure sensor 44. The ECU 100 controls the electric power supplied to the actuator of the damping force variable absorber 22 so that the damping force acts on the lower arm 14 and the upper vehicle body 24 according to the estimated force. In this way, the ECU 100 sets a damping force suitable for suppressing the vibration of the upper vehicle body 24 according to the force acting on the lower arm 14 and the upper vehicle body 24. Therefore, the ECU 100 functions as a damping force control unit that controls the damping force variable absorber 22 so as to change the damping force according to the force acting on the first support unit and the second support unit.

  Thus, by setting the damping force of the damping force variable absorber 22 according to the negative pressure of the brake booster 40, it is possible to effectively suppress the vibration of the upper vehicle body 24. Therefore, the ECU 100 also functions as a vibration control unit that suppresses the vibration of the upper vehicle body 24 according to the force acting on the lower arm 14 and the upper vehicle body 24 when the first vacuum pump 15 is operated.

  The present invention is not limited to the above-described embodiments, and an appropriate combination of the elements of each embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to each embodiment based on the knowledge of those skilled in the art, and embodiments to which such modifications are added can also be included in the scope of the present invention. Here are some examples.

  The negative pressure sensor 44 may be provided in the first vacuum pump 15. In this case, the negative pressure sensor 44 detects the pressure in the cylinder chamber of the first vacuum pump 15. The ECU 100 controls the electric power supplied to the actuator of the damping force variable absorber 22 according to the negative pressure of the first vacuum pump 15. Also in this manner, the ECU 100 can set a damping force suitable for suppressing the vibration of the upper vehicle body 24 according to the force acting on the lower arm 14 and the upper vehicle body 24, and the vibration of the upper vehicle body 24 can be reduced. It becomes possible to suppress effectively. Needless to say, the negative pressure sensor 44 may be provided in the vacuum tank 30.

It is the whole vacuum pump system lineblock diagram concerning this embodiment.

Explanation of symbols

  10 vacuum pump system, 12 wheels, 14 lower arm, 15 first vacuum pump, 16 piston, 18 cylinder, 20 suspension, 22 damping force variable absorber, 24 upper body, 30 vacuum tank, 36 pump motor, 38 2nd vacuum pump, 40 brake booster, 42 brake pedal, 44 negative pressure sensor, 100 ECU.

Claims (4)

Vacuum that generates a negative pressure by using a change in relative position between a first support part that supports a wheel and a second support part that supports a vehicle cabin and is supported by the first support part via a suspension. A pump,
A vibration control unit that suppresses vibration of the second support unit according to a force acting on the first support unit and the second support unit when the vacuum pump is operated;
A vacuum pump system for a vehicle, comprising:   The vibration control unit includes a damping force variable unit that changes a damping force that interacts with the first support unit and the second support unit, and the first support unit and the second support unit when the vacuum pump operates. The vehicle vacuum pump system according to claim 1, further comprising: a damping force control unit that controls the damping force variable unit so as to change the damping force according to a force acting on the support unit. A negative pressure sensor for detecting the negative pressure of the brake booster;
3. The vehicle vacuum pump system according to claim 1, wherein the vibration control unit suppresses vibration of the second support unit according to the detected negative pressure of the brake booster. A negative pressure sensor for detecting a negative pressure of the vacuum pump;
The said vibration control part suppresses the vibration of the said 2nd support part according to the negative pressure of the detected said vacuum pump, The vacuum pump system for vehicles of Claim 1 or 2 characterized by the above-mentioned.

Images