JP2014111407A - Negative pressure assistor and brake system using negative pressure assistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress variation of input which may occur when a reactive force is blocked.SOLUTION: When pressure reduction control for W/C pressure is performed, an ECU 40 opens a pressure difference reduction valve 37, whereby a transformation chamber 18 and a constant pressure chamber 17 is communicated with each other through a passage 36. Thus, air in the transformation chamber 18 flows into the constant pressure chamber 17 thereby increasing the negative pressure level in the transformation chamber 18, and consequently, the pressure difference between the transformation chamber and the constant pressure chamber is reduced, whereby a reactive force is increased by a power piston 19 and advancement of an input shaft 28 is prevented. Therefore, when pressure reduction control for W/C pressure is performed during operation of a regenerative cooperation brake, variation of a pedal effort can be effectively suppressed.

Description

  The present invention relates to a technical field of a negative pressure booster capable of suppressing input fluctuation when a reaction force is interrupted and a brake system using the negative pressure booster. In the claims and the description of the claims, “front” refers to the direction in which the input shaft advances (that is, the operating direction) by input, and “rear” refers to the direction in which the input shaft returns due to the disappearance of input.

  2. Description of the Related Art Conventionally, a negative pressure booster using negative pressure is often used in a brake system of an automobile such as a passenger car. In such a conventional general negative pressure booster, when the input shaft moves forward during brake operation by depressing the brake pedal, the valve plunger connected to the input shaft also moves forward and is disposed in the valve body. The valve body is also seated on the vacuum valve seat formed on the valve body and the vacuum valve is closed.At the same time, the atmospheric valve seat formed on the valve plunger is separated from the valve body and the atmospheric valve opens. The variable pressure chamber in which the pressure is introduced is cut off from the constant pressure chamber in which the negative pressure is constantly introduced and communicated with the atmosphere. Then, the air is introduced into the variable pressure chamber through the open atmospheric valve, and a differential pressure is generated between the variable pressure chamber and the constant pressure chamber, so that the power piston moves forward. A booster boosts the input of the input shaft (that is, pedaling force) by a predetermined servo ratio and outputs the boosted signal. Due to the output of the negative pressure booster, the piston of the master cylinder moves forward, the master cylinder generates a master cylinder pressure, and the wheel cylinder is operated by this master cylinder pressure, and the normal brake is operated.

  By the way, in recent years, an automobile brake system includes a regenerative brake system that performs braking with a regenerative braking force when the kinetic energy of the automobile is converted into electric energy during recovery and a friction brake system that performs braking with a friction brake force. A coordinated regenerative braking system has been proposed (see, for example, Patent Document 1).

  In the regenerative cooperative brake system described in Patent Document 1, the wheel cylinder pressure of the wheel cylinder of the friction brake is controlled to be reduced in order to reduce the friction brake force by the regenerative brake force during the regenerative cooperative brake. In this case, this regenerative cooperative braking system uses the above-described negative pressure booster to boost the pedal effort and obtain a large braking force.

  In addition, as a conventional negative pressure booster, by connecting the constant pressure chamber and the variable pressure chamber of the negative pressure booster with a passage, an electromagnetic control valve is disposed in this passage, and by controlling the electromagnetic control valve, A negative pressure booster that controls the output of the negative pressure booster is known (see, for example, Patent Documents 2 and 3).

  In these negative pressure boosters described in Patent Documents 2 and 3, both the variable pressure chamber and the constant pressure chamber are connected by a passage (pipe) disposed outside the shell constituting the external shape of the negative pressure booster. In addition, an electromagnetic control valve is disposed in this passage. And the output of a negative pressure booster is controlled by controlling an electromagnetic control valve and controlling the differential pressure | voltage of a variable pressure chamber and a constant pressure chamber.

By the way, a conventionally known general negative pressure booster includes a vacuum valve and an atmospheric valve for selectively switching and connecting the variable pressure chamber to either the constant pressure chamber or the atmosphere. FIG. 5 is a partial cross-sectional view schematically showing portions of a vacuum valve and an atmospheric valve of a conventional general negative pressure booster. FIGS. 6A and 6B are diagrams for explaining the vacuum valve and the state when the vacuum valve is operated. In FIG. 5, 101 is a negative pressure booster, 102 is an input shaft, 103 is a valve body, 104 is a valve plunger, 105 is a valve body, and 106 is a vacuum valve portion 105a of the valve body 5 and a vacuum valve seat 103a. A vacuum valve 107 is an atmospheric valve composed of the atmospheric valve portion 105b of the valve body 5 and an atmospheric valve seat 104a, 108 is a valve spring that constantly urges the valve body 105, 109 is a power piston, and 110 is always supplied with negative pressure. The constant pressure chamber 111 is a variable pressure chamber into which negative pressure is introduced and the atmosphere is introduced when the negative pressure booster is not in operation, 112 is an atmospheric introduction passage, 113 is a negative pressure introduction passage, and 114 is an output shaft. 115 is a reaction disk, and 116 is a return spring.

  Then, when the negative pressure booster 101 in which the input shaft 102 does not advance because the brake pedal (not shown) is not depressed, each member of the negative pressure booster 101 is in the state shown in FIG. In this inoperative state, the vacuum valve 106 is opened and the atmospheric valve 107 is closed, so that the variable pressure chamber 111 is connected to the constant pressure chamber 110 and is cut off from the atmosphere. Thereby, there is substantially no pressure difference between the constant pressure chamber 110 and the variable pressure chamber 111, and the power piston 109 does not operate. Therefore, the negative pressure booster 101 does not output from the output shaft 114.

  Moreover, when the brake pedal is depressed and the input shaft 102 moves forward, the negative pressure booster 101 operates. When the negative pressure booster 101 is activated, the valve plunger 104 moves forward by the input shaft 102 moving forward. Then, as shown in FIG. 6A, the vacuum valve portion 105a comes into contact with the vacuum valve seat 103a to close the vacuum valve 106, and the atmospheric valve portion 105b is separated from the atmospheric valve seat 104a to open the atmospheric valve 107. Then, since the variable pressure chamber 111 is cut off from the constant pressure chamber 110 and connected to the atmosphere, the atmosphere is introduced into the variable pressure chamber 111. As a result, a pressure difference is generated between the constant pressure chamber 110 and the variable pressure chamber 111, the power piston 109 is operated, and the power piston 109 and the output shaft 114 are moved forward. Therefore, the negative pressure booster 101 outputs from the output shaft 114.

  The reaction force is transmitted from the output shaft 114 to the reaction disc 115 by the output from the output shaft 114, and this reaction force is transmitted from the reaction disc 115 to the driver via the valve plunger 104, the input shaft 102, and the brake pedal. The Thereby, the driver recognizes the brake operation.

  Further, the valve body 103 moves forward and the reaction force applied to the valve plunger 104 reduces the opening amount of the opened atmospheric valve 107 so that both the atmospheric valve 107 and the vacuum valve 106 are closed. Thereby, the atmosphere is not introduced into the atmosphere valve 107, and the pressure in the constant pressure chamber 110 and the pressure in the variable pressure chamber 111 are substantially balanced. At this time, the negative pressure booster 101 generates an output in which the input of the input shaft 102 (that is, a force corresponding to the pedal depression force) is boosted by a predetermined servo ratio.

  On the other hand, when the brake pedal is released to release the brake operation after the brake operation, the input shaft 102 moves backward. As the input shaft 102 moves backward, the valve plunger 104 also moves backward. Then, as shown in FIG. 6B, the atmospheric valve portion 105b is separated from the atmospheric valve seat 104a and the atmospheric valve 107 is opened, and the vacuum valve portion 105a is separated from the vacuum valve seat 103a and the vacuum valve 106 is open. Then, since the variable pressure chamber 111 is cut off from the constant pressure chamber 110 and connected to the atmosphere, the atmosphere is introduced into the variable pressure chamber 111. As a result, a pressure difference is generated between the constant pressure chamber 110 and the variable pressure chamber 111, the power piston 109 is operated, and the power piston 109 and the output shaft 114 are moved forward. Therefore, the negative pressure booster 101 outputs from the output shaft 114.

Japanese Patent Application Laid-Open No. 2002-255018. JP-A-10-29529. Japanese Patent Laid-Open No. 10-35471.

  By the way, when this type of negative pressure booster is used in the regenerative cooperative brake system described in Patent Document 1, in the regenerative cooperative brake operation, the reaction force due to the hydraulic pressure is negative pressure boost during the pressure reduction control of the wheel cylinder pressure. Since the device is cut off, the relationship between the pressure difference between the above-described variable pressure chamber pressure and constant pressure chamber pressure balanced by this reaction force is broken by the load of the valve spring that urges the valve body.

  This will be explained in a little more detail. As shown in FIG. 6A, when the brake is operated (that is, when the brake pressure is increased), the vacuum valve portion 105a comes into contact with the vacuum valve seat 103a as the input shaft 102 advances. When the atmospheric valve portion 105b is separated from the atmospheric valve seat 104a, the valve contact force F due to the load of the valve spring 108 is applied from the valve body 105 to the valve body 103 (that is, the power piston 109). Is not added.

  On the other hand, as shown in FIG. 6B, when the brake operation is released (that is, when the brake pressure is reduced), the atmospheric valve seat 104a comes into contact with the atmospheric valve portion 105b as the input shaft 102 moves backward, and the vacuum valve portion 105a is vacuumed. By separating from the valve seat 103a, the valve contact force F due to the load of the valve spring 108 is applied from the valve body 105 to the input shaft 102 (that is, the brake pedal) via the valve plunger 104, but the valve body 103 (that is, , Is not added to the power piston 109). At this time, since the direction of the valve contact force F applied to the valve plunger 104 is the same as the direction of the pedal depression force, the pedal depression force is reduced. Therefore, when this type of negative pressure booster is used in the regenerative cooperative brake system described in Patent Document 1, the pedal depression force fluctuates during wheel cylinder pressure reduction control in the regenerative cooperative brake operation.

  Although the negative pressure booster described in Patent Documents 2 and 3 controls the output by controlling the differential pressure between the variable pressure chamber and the constant pressure chamber by controlling the electromagnetic control valve, the reaction force is blocked as described above. In this case, no consideration is given to fluctuations in the pedaling force caused by the load of the valve spring.

  The present invention has been made in view of such circumstances, and an object of the present invention is to use a negative pressure booster that can effectively suppress fluctuations in input that occur when a reaction force is interrupted, and the same. Was to provide a braking system.

  In order to solve the above-described problems, a negative pressure booster according to the present invention includes a front shell and a rear shell that form an internal space, a valve body that passes through the rear shell in an airtight and slidable manner, and a valve body. The internal space is hermetically partitioned into a constant pressure chamber connected to a negative pressure source and a variable pressure chamber into which the atmosphere can be introduced, and the output is operated by a pressure difference between the variable pressure chamber and the constant pressure chamber. Operation of the power piston, the vacuum valve for controlling the communication between the variable pressure chamber and the constant pressure chamber, and the atmosphere valve for controlling the communication between the variable pressure chamber and the outside atmosphere An input shaft that moves forward by the operation member and moves backward by releasing the operation of the operation member to control the operation of the vacuum valve and the atmospheric valve, and a valve plunger that is controlled by movement of the input shaft. An output shaft that outputs the output generated by the power piston to the outside, a reaction force mechanism that transmits a reaction force according to the output from the output shaft to the input shaft via the valve plunger, and It is characterized by comprising at least input fluctuation suppressing means for reducing a pressure difference between the variable pressure chamber pressure of the variable pressure chamber and the constant pressure chamber pressure of the constant pressure chamber when the reaction force is interrupted to suppress fluctuations in input.

  Further, in the negative pressure booster of the present invention, the input fluctuation suppressing means is arranged in a pressure difference reducing passage that bypasses the vacuum valve and connects the variable pressure chamber and the constant pressure chamber, and the pressure difference reducing passage. And a pressure difference reducing valve that is normally closed and opened when the reaction force is interrupted.

  Furthermore, the negative pressure booster of the present invention is characterized in that both the pressure difference reducing passage and the pressure difference reducing valve are provided outside the front shell and the rear shell.

  Furthermore, the negative pressure booster of the present invention includes a front shell and a rear shell that form an internal space, a valve body that passes through the rear shell in an airtight manner and is slidable, and is attached to the valve body so that the internal space passes through the internal space. A power piston that is hermetically partitioned into a constant pressure chamber connected to a negative pressure source and a variable pressure chamber into which air can be introduced, and that operates with a pressure difference between the variable pressure chamber and the constant pressure chamber to generate an output; and A vacuum valve for controlling communication and blocking between the variable pressure chamber and the constant pressure chamber, an air valve for controlling communication and blocking between the variable pressure chamber and the outside atmosphere, and a forward movement by the operation of the operation member and the operation An input shaft that moves backward by releasing the operation of the member to control the operation of the atmospheric valve, an output shaft that outputs the output generated by the power piston to the outside, and a reaction force corresponding to the output from the output shaft A reaction force mechanism that transmits to the input shaft, and an input that suppresses input fluctuations by reducing a pressure difference between the variable pressure chamber pressure of the variable pressure chamber and the constant pressure chamber pressure of the constant pressure chamber when the reaction force is interrupted during operation. At least a fluctuation suppressing means, and the atmospheric valve is provided in the valve body and introduces an atmospheric air into the variable pressure chamber; and a piston-shaped piston that is fixed to the input shaft and controls the opening and closing of the atmospheric air introduction hole. The input fluctuation suppression means is constituted by the vacuum valve.

  Furthermore, the negative pressure booster of the present invention includes a front shell and a rear shell that form an internal space, a valve body that passes through the rear shell in an airtight manner and is slidable, and is attached to the valve body so that the internal space passes through the internal space. A power piston that is hermetically partitioned into a constant pressure chamber connected to a negative pressure source and a variable pressure chamber into which air can be introduced, and that operates with a pressure difference between the variable pressure chamber and the constant pressure chamber to generate an output; and A vacuum valve for controlling communication and blocking between the variable pressure chamber and the constant pressure chamber, an air valve for controlling communication and blocking between the variable pressure chamber and the outside atmosphere, and a forward movement by the operation of the operation member and the operation An input shaft that moves backward by releasing the operation of the member to control the operation of the atmospheric valve, an output shaft that outputs the output generated by the power piston to the outside, and a reaction force corresponding to the output from the output shaft A reaction force mechanism that transmits to the input shaft, and an input that suppresses input fluctuations by reducing a pressure difference between the variable pressure chamber pressure of the variable pressure chamber and the constant pressure chamber pressure of the constant pressure chamber when the reaction force is interrupted during operation. At least a fluctuation suppressing means, and the atmospheric valve is provided in the valve body and introduces an atmospheric air into the variable pressure chamber; and a piston-shaped piston that is fixed to the input shaft and controls the opening and closing of the atmospheric air introduction hole. A pressure difference reducing passage that bypasses the vacuum valve and connects the variable pressure chamber and the constant pressure chamber, and a pressure difference reducing passage that is normally disposed in the pressure difference reducing passage. And a pressure difference reducing valve that is closed when the reaction force is interrupted.

  Furthermore, the negative pressure booster of the present invention is characterized in that both the pressure difference reducing passage and the pressure difference reducing valve are provided outside the front shell and the rear shell.

Meanwhile, the brake system of the present invention includes a brake operation member, a negative pressure booster that operates by operating the brake operation member and boosts and outputs the brake operation force of the brake operation member, and the negative pressure multiplier A master cylinder that is operated by an output of a force device to generate brake fluid pressure, a brake cylinder that generates brake force by introducing brake fluid pressure generated in the master cylinder, the master cylinder, and the brake cylinder At least a hydraulic pressure control unit that controls a brake hydraulic pressure that is disposed in a brake fluid passage between the hydraulic cylinder and the brake cylinder, and that controls the hydraulic pressure control unit. The force device is any one of the negative pressure boosters of the present invention described above, and the input fluctuation suppressing means of the negative pressure booster is the Brake operation force fluctuation suppression means for suppressing fluctuations in the brake operation force of the rake operation member, and the control unit is configured to reduce the hydraulic pressure of the brake hydraulic pressure introduced into the brake cylinder when the negative pressure booster is operated. The pressure difference between the variable pressure chamber pressure of the variable pressure chamber and the constant pressure chamber pressure of the constant pressure chamber is reduced by operating the brake operation force fluctuation suppressing means during pressure reduction control by the control unit.

  According to the negative pressure booster of the present invention configured as described above, the pressure difference between the variable pressure chamber pressure and the constant pressure chamber pressure is reduced by the input fluctuation suppressing means when the reaction force is interrupted during operation. Thereby, the reaction force by the power piston can be increased to prevent the input shaft from moving forward. Therefore, it is possible to effectively suppress fluctuations in the input of the negative pressure booster when the reaction force is interrupted.

  Further, according to the brake system of the present invention, during the brake cylinder pressure reduction control, the brake operation force fluctuation suppression means when the reaction force is interrupted at the time of the brake operation, the variable pressure chamber pressure and the constant pressure chamber pressure of the negative pressure booster are controlled. The pressure difference is reduced. Thereby, the reaction force by the power piston can be increased to prevent the input shaft from moving forward. Therefore, the negative pressure level of the variable pressure chamber rises due to the flow of air in the variable pressure chamber to the constant pressure chamber, so the pressure difference between the variable pressure chamber pressure and the constant pressure chamber pressure is reduced, and the reaction force by the power piston is increased and input. It is possible to prevent the shaft from moving forward. As a result, it is possible to effectively suppress the fluctuation of the brake operation force during the pressure reduction control of the brake cylinder pressure, and to maintain the operation feeling of the brake operation member satisfactorily.

It is a figure showing typically an example of an embodiment of a brake system concerning the present invention. It is sectional drawing which shows an example of embodiment of the negative pressure booster based on this invention used for the brake system shown in FIG. 1 in a non-operation state. It is a block diagram for reaction force fluctuation suppression of the brake system shown in FIG. It is a partial expanded sectional view partially showing other examples of an embodiment of a negative pressure booster concerning the present invention. It is a fragmentary sectional view which shows typically the part of the vacuum valve and atmospheric valve of the conventional general negative pressure booster. (A) And (B) is a figure explaining the state at the time of the action | operation of a vacuum valve and a vacuum valve.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing an example of an embodiment of a brake system according to the present invention. In the following description, “front” and “rear” indicate “left” and “right” in each figure, respectively.

  The brake system in this example is a regenerative cooperative brake system including a friction brake system and a regenerative brake system. This regenerative braking system is necessary from the regenerative braking force and the friction braking force by operating the regenerative braking system in cooperation with the friction brake system as necessary when the brake such as the normal brake is operated by the friction brake system. Brake power is gained.

As shown in FIG. 1, the friction brake system 1 in the brake system of this example boosts the pedal force of the brake pedal 2 (corresponding to the operation member and the brake operation member in the present invention) and the brake pedal 2 with a negative pressure. Output negative pressure booster 3 and a tandem master cylinder (hereinafter simply referred to as M / C pressure) that is actuated by the output of negative pressure booster 3 to generate a master cylinder pressure (hereinafter also referred to as M / C pressure). 4) and the M / C pressure of each fluid chamber of M / C4 is supplied through two passages 5 and 6 (corresponding to the brake fluid passage of the present invention), respectively. Brake cylinder (hereinafter also referred to as W / C) 7, 8, 9, 10 (in this example, W / C 7 is provided for the right rear wheel RR, and W / C
C8 is provided for the left front wheel LF, W / C9 is provided for the right front wheel RF, W / C10 is provided for the left rear wheel LR, and so-called brake piping is X piping. However, the present invention is not limited to this, and any other known piping type such as front and rear piping may be used), two systems of brake fluid pressure control device (H / U) 11, and a reservoir 12 for storing brake fluid A pedal stroke sensor (S / U) 13 for detecting depression of the brake pedal 2 is provided.

FIG. 2 is a sectional view showing an example of the embodiment of the negative pressure booster according to the present invention in a non-operating state.
As shown in FIG. 2, the negative pressure booster 3 is basically the same as a conventionally known general negative pressure booster. That is, the negative pressure booster 3 includes a front shell 14 and a rear shell 15 that are coupled to each other to form an internal space, a valve body 16 that penetrates the rear shell 15 in an airtight and slidable manner, and enters the internal space. A constant pressure chamber 17 disposed between the outer periphery of the valve body 16 in the space and the coupling portion of the front shell 14 and the rear shell 15 to connect the internal space to a negative pressure source (not shown) and introduce negative pressure, and negative pressure On the inner peripheral surface of the valve body 16, a power piston 19 that is airtightly partitioned into a variable pressure chamber 18 into which air is introduced when the booster 3 is operated, a valve plunger 20 that is slidably disposed on the valve body 16, and The valve body 21 is supported, the vacuum valve seat 23 is provided on the inner peripheral surface of the valve body 16 and forms a poppet valve-like vacuum valve 22 in cooperation with the valve body 21, An atmospheric valve seat 25 is provided at the rear end of the jar 20 and forms a poppet valve-like atmospheric valve 24 in cooperation with the valve body 21, and the valve body 21 is always attached to the vacuum valve seat 23 and the atmospheric valve seat 25. The valve spring 26 and the valve body 16 are pierced through the valve body 16 in a direction perpendicular to or substantially perpendicular to the direction of movement of the valve body 16 (left-right direction in FIG. 2) so as to be movable relative to the valve body 16 by a predetermined amount. 20 is connected to a key member 27 and a valve plunger 20 which are supported so as to be able to move relative to each other by a predetermined amount in the moving direction of the valve plunger 20 (left and right in FIG. 2). And the input shaft 28 that moves forward when the brake pedal 2 is depressed and moves backward when the brake pedal 2 is depressed, An output shaft 29 that is supported by the body body 16 so as to be relatively slidable and outputs the power generated by the power piston 19, and a reaction disk 30 disposed between the valve body 16 and the output shaft 29 (reverse to the present invention). Equivalent to a force mechanism), a spacing member 31 disposed between the valve plunger 20 and the reaction disk 30, a return spring 32 that constantly biases the valve body 16 to the inoperative position shown in FIG. An air discharge passage 33 that is formed and discharges air from the variable pressure chamber 18 through the constant pressure chamber 17 to the outside, and an air introduction passage 34 that is formed in the valve body 16 and allows air (air) to be introduced from the outside to the variable pressure chamber 18. And a negative pressure introduction passage 35 for introducing a negative pressure into the constant pressure chamber 17 from the outside.

  The vacuum valve 22 controls communication and blocking between the variable pressure chamber 18 and the constant pressure chamber 17, and the atmospheric valve 24 controls communication and blocking between the variable pressure chamber 18 and the outside atmosphere. Since the operation of the basic configuration of the negative pressure booster 3 is the same as the operation of a conventionally known general negative pressure booster, a description thereof will be omitted.

In addition to the basic configuration, the negative pressure booster 3 is provided outside the front shell 14 and the rear shell 15 by bypassing the vacuum valve 22 in the same manner as the negative pressure booster described in Patent Document 1. In order to reduce the pressure difference between the variable pressure chamber 18 and the constant pressure chamber 17 by connecting the variable pressure chamber 18 and the constant pressure chamber 17, a pressure difference reducing passage (pipe) through which the air in the variable pressure chamber 18 flows out to the constant pressure chamber 17. 36, a pressure difference control valve 37 comprising a normally closed electromagnetic on-off valve which is disposed in the pressure difference reduction passage 36 and communicates and blocks the pressure difference reduction passage 36, and a pressure change chamber pressure sensor 38 which detects the pressure in the pressure change chamber 18. And a constant pressure chamber pressure sensor 39 for detecting the pressure in the constant pressure chamber 17. The pressure difference reducing passage 36, the pressure difference control valve 37, the variable pressure chamber pressure sensor 38, and the constant pressure chamber pressure sensor 39 constitute the input fluctuation suppressing means and the brake operation force fluctuation suppressing means of the present invention. The pressure difference control valve 37, the variable pressure chamber pressure sensor 38, and the constant pressure chamber pressure sensor 39 are all connected to an electronic control unit (ECU) 40.

  M / C4 is a conventionally well-known general tandem type M / C having a primary piston and a secondary piston (both not shown). Therefore, although the detailed description is omitted, the primary piston is operated by the output of the negative pressure booster 3 to generate the M / C pressure in the first hydraulic pressure chamber (not shown), and this M / C pressure Then, the secondary piston is operated to generate the M / C pressure in the second hydraulic pressure chamber (not shown).

As shown in FIG. 1, the one-way passage 5 is connected to the first hydraulic chamber of the M / C 4. The one passage 5 is branched into first and second branch passages 5a and 5b. The first branch passage 5a is connected to the W / C 7 for braking the right rear wheel RR of the one passage, The branch passages 5b are respectively connected to W / C8 for braking the left front wheel LF of one system. The other system passage 6 is connected to the second hydraulic chamber of the M / C 4. This passage 6 is also branched into third and fourth branch passages 6a and 6b, and the third branch passage 6a is a W for braking the right front wheel RF of another system.
Also, the fourth branch passage 6b is connected to W / C10 for braking the left rear wheel LR of another system.

The H / U 11 is disposed in the passages 5, 5a, 5b, 6, 6a, 6b of each system between the M / C 4 and each W / C 7, 8, 9, 10. The H / U 11 includes a normally open first electromagnetic open / close valve 41, a first check valve 42, a normally open second electromagnetic open / close valve 43, a second check valve 86, first and second pressure increasing valves 44, 45, 2 and third check valves 46, 47, a first discharge passage 48, a first pressure reducing valve 49, a first low pressure accumulator 50 for discharged brake fluid, a second discharge passage 51, a second pressure reducing valve 52, a first pump unit 53, Passage 54, third and fourth pressure increasing valves 55, 56, fourth and fifth check valves 57, 58, third discharge passage 59, third pressure reducing valve 60, second pump unit 61, fourth discharge passage 62, second 4 pressure reducing valve 63, passage 64, W / C pressure sensor 65, motor (M) 66, passage 67, first brake fluid introduction valve 68, M / C pressure sensor 69, passage 70, second brake fluid introduction valve 71, Low pressure accumulator 72 for second discharged brake fluid, first It has a relief valve 87, a second relief valve 88, a first accumulator 89, and a second accumulator 90.

The first electromagnetic on-off valve 41 is disposed in the passage 5 between the M / C 4 and the branch point A of the first and second branch passages 5a and 5b. The first check valve 42 is provided in parallel with the first electromagnetic open / close valve 41 and allows only the flow of brake fluid from the M / C 4 side to the W / C 7, 8 side of the first electromagnetic open / close valve 41. The second electromagnetic opening / closing valve 43 is an electromagnetic valve similar to the first electromagnetic opening / closing valve 41, and is disposed in the passage 6 between the M / C 4 and the branch point B of the third and fourth branch passages 6a, 6b. . First and second
The pressure-increasing valves 44 and 45 are disposed in the first and second branch passages 5a and 5b, respectively, and are configured by normally open electromagnetic on-off valves. The second and third check valves 46 and 47 are respectively
It is provided in parallel with the first and second pressure increasing valves 44 and 45, and only allows the flow of brake fluid from the W / C 7, 8 side of the first and second pressure increasing valves 44, 45 to the M / C 4 side. The first discharge passage 48 is provided so as to be branched from the first branch passage 5 a on the W / C 7 side from the first pressure increasing valve 44 and connected to the suction side of the first pump unit 53.

The first pressure reducing valve 49 is disposed in the first discharge passage 48 and is constituted by a normally closed electromagnetic on-off valve. The first discharge brake fluid low-pressure accumulator 50 is disposed in the first discharge passage 48 on the opposite side of the first pressure reducing valve 49 from the W / C 7 side. The second discharge passage 51 is branched from the second branch passage 5b on the W / C8 side from the second pressure increasing valve 45, and is a first discharge passage between the first pressure reducing valve 49 and the first low pressure accumulator 50 for discharged brake fluid. 48 to be connected. The second pressure reducing valve 52 is disposed in the second discharge passage 51 and is configured by an electromagnetic opening / closing valve similar to the first pressure reducing valve 49. A first relief valve 87 is provided in the first discharge passage 48 on the suction side of the first pump unit 53 from the first discharge brake fluid low-pressure accumulator 50. The first relief valve 87 is opened when the hydraulic pressure of the first exhaust brake fluid low-pressure accumulator 50 becomes equal to or higher than a predetermined pressure, and the fluid pressure of the first exhaust brake fluid low-pressure accumulator 50 is controlled by the first pump unit 53. Release to the suction side. The suction side of the first pump unit 53 is connected to the first discharge passage 48 on the side opposite to the W / C 7 side of the first pressure reducing valve 49. The discharge side of the first pump unit 53 is connected to the passage 5 between the first electromagnetic on-off valve 41 and the branch point A via the passage 54.

The third and fourth pressure boosting valves 55 and 56 are disposed in the third and fourth branch passages 6a and 6b, respectively, and are configured by electromagnetic open / close valves similar to the first and second pressure boosting valves 44 and 45, respectively. .
The fourth and fifth check valves 57 and 58 are provided in parallel with the third and fourth pressure increasing valves 55 and 56, respectively, and the M / M from the W / C 9,10 side of the third and fourth pressure increasing valves 55 and 56 are respectively. Only the flow of brake fluid to the C4 side is allowed. The third discharge passage 59 is provided to be branched from the third branch passage 6a on the W / C 9 side from the third pressure increasing valve 55. The third pressure reducing valve 60 is disposed in the third discharge passage 59 and is configured by an electromagnetic opening / closing valve similar to the first pressure reducing valve 49. The suction side of the second pump unit 61 is connected to the third discharge passage 59 on the side opposite to the W / C 9 side of the third pressure reducing valve 60. The discharge side of the second pump unit 61 is connected to the passage 6 between the second electromagnetic opening / closing valve 43 and the branch point B via the passage 64. The fourth discharge passage 62 is branched from the fourth branch passage 6 b on the W / C 10 side from the fourth pressure increasing valve 56, and enters the third discharge passage 59 between the third pressure reducing valve 60 and the suction side of the second pump unit 61. Connected. The fourth pressure reducing valve 63 is disposed in the fourth discharge passage 62 and is configured by an electromagnetic opening / closing valve similar to the first pressure reducing valve 49. The W / C pressure sensor 65 is disposed in the third branch passage 6a on the W / C 9 side from the third pressure increasing valve 55 and detects the W / C pressure of the W / C 9. The motor (M) 66 drives the first and second pump units 53 and 61.

  The passage 67 bypasses the first pump unit 53 and connects the first discharged brake fluid low-pressure accumulator 50 and the passage 5 on the M / C 4 side from the first electromagnetic opening / closing valve 41. The first brake fluid introduction valve 68 is disposed in the passage 67 for introducing brake fluid from the M / C 4 and is constituted by a normally closed electromagnetic on-off valve. The M / C pressure sensor 69 is disposed in the passage 67 on the M / C4 side of the first brake fluid introduction valve 68 and detects the M / C pressure of the M / C4. The passage 70 bypasses the second pump unit 61 and connects the second low-pressure accumulator 72 for discharged brake fluid and the passage 6 on the M / C 4 side from the second electromagnetic opening / closing valve 42. The second brake fluid introduction valve 71 is disposed in the passage 70 for introducing brake fluid from the M / C 4 and is constituted by a normally closed electromagnetic on-off valve.

  As shown in FIG. 3, the ECU 40 includes a pedal depression force calculation unit 73, a necessary total brake force calculation unit 74, a regenerative brake necessity determination unit 75, a necessary regenerative brake force calculation unit 76, a regenerative brake control signal output unit 77, and a necessary friction brake. It has a force calculation unit 78, a brake fluid pressure control signal output unit 79, a necessary pressure difference calculation unit 80, and a pressure difference control signal output unit 81.

When a normal brake operation is performed by depressing the brake pedal 2 and an M / C pressure signal is input from the M / C pressure sensor 69, the pedal depression force calculation unit 73 performs the current operation based on the M / C pressure signal. The pedal depression force when the brake pedal 2 is depressed is calculated. When the pedal depression force signal from the pedal depression force calculation unit 73 is input, the necessary total brake force calculation unit 74 calculates the necessary overall brake force at this time based on the pedal depression force signal. Similarly, the regenerative brake necessity determination unit 75 determines that a brake operation has been performed when a pedal stroke signal is input from the pedal stroke sensor 13, and determines whether or not a regenerative brake is necessary based on a preset regenerative brake operation condition. Determine whether. This regenerative brake operation condition can be set as a speed condition where the vehicle traveling speed is extremely low (for example, 4 km / hour, etc.). Therefore, when the brake pedal is depressed during normal traveling of the vehicle, the regenerative brake operation condition is established because the vehicle is traveling at a relatively high speed, and the regenerative brake is operated together with the friction brake. . At this time, the regenerative brake acts on the left and right front wheels LF and RF.
When the regenerative brake necessary signal is input from the regenerative brake necessity determining unit 75, the necessary regenerative brake force calculating unit 76 calculates the necessary regenerative brake force at this time. The regenerative brake control signal output unit 77 outputs a regenerative brake control signal to the regenerative brake 82 based on the regenerative brake force from the necessary regenerative brake force calculation unit 76.

  The required friction brake force calculating unit 78 is configured to generate a friction brake based on the required total brake force calculated by the required total brake force calculating unit 74 and the required regenerative brake force calculated by the required regenerative brake force calculating unit 76. A necessary friction brake force for obtaining the entire brake force calculated by the necessary total brake force calculation unit 74 is calculated by combining the force with the regenerative brake force. The brake fluid pressure control signal output unit 79 is based on the necessary friction brake force signal from the necessary friction brake force calculation unit 78 and the W / C pressure signal detected by the W / C pressure sensor 65, and the brake fluid pressure in the friction brake. Output a control signal. By this brake fluid pressure control signal, the brake fluid pressure control solenoid valves, that is, the first to fourth pressure increasing valves 44, 45, 55, 56, the first to fourth pressure reducing valves 49, 52, 60, 63 and the motor (M). 66 are controlled to operate as required.

  The necessary pressure difference calculation unit 80 calculates the difference between the variable pressure in the variable pressure chamber 18 and the constant pressure in the constant pressure chamber 17 when the brake hydraulic pressure control signal from the brake hydraulic pressure control signal output unit 79 is a brake hydraulic pressure reduction signal. The necessary pressure difference between them is calculated and a pressure difference signal is output. In other words, a necessary pressure difference between the variable pressure chamber pressure and the constant pressure chamber pressure necessary for suppressing the fluctuation of the pedal depression force due to the load of the valve spring 26 is calculated. The pressure difference control signal output unit 81 outputs a pressure difference control signal to the pressure difference control valve 37 based on the necessary pressure difference signal from the necessary pressure difference calculation unit 80.

In the friction brake system 1 of the brake system of this example configured as above, all the components are in the non-operating positions shown in FIGS. 1 and 2 when the brake is not operated when the brake pedal 2 is not depressed. . Therefore, in this brake non-operating state, the negative pressure booster 3 does not operate and the M / C 4 does not generate the M / C pressure. As a result, each of the W / Cs 7, 8, 9, and 10 has a corresponding passage 5a, 5b; 6a, 6b, the first to fourth pressure increasing valves 44,
45, 55, 56, the respective passages 5, 6, the first and second electromagnetic on-off valves 41, 43, and the hydraulic chambers of the M / C 4 communicate with the reservoir 12 to be at atmospheric pressure. Therefore, no W / C pressure (brake fluid pressure) is generated in each W / C 7, 8, 9, 10. Furthermore, the motor (M) 66
Is not activated, the first and second pump units 53 and 61 are also not activated. Further, the pressure difference control valve 37 is closed and the passage 36 is blocked. Further, the regenerative brake 82 of the regenerative brake system does not operate.

  When the vehicle is traveling in a state where the above-described regenerative brake operation condition is satisfied, if the driver performs a brake operation by depressing the brake pedal 2 from this brake non-operation state, the regenerative brake operation condition is satisfied Therefore, the regenerative brake necessity determination unit 75 of the ECU 40 outputs a regenerative brake necessity signal based on the pedal depression signal from the pedal stroke sensor 13. Then, the necessary regenerative braking force calculation unit 76 calculates the necessary regenerative braking force and outputs this necessary regenerative braking force signal. Then, the regenerative brake control signal output unit 77 outputs a regenerative brake control signal to the regenerative brake 82 based on the necessary regenerative brake force signal. As a result, the regenerative brake 82 of the regenerative brake system operates. In that case, the regenerative braking force by the regenerative brake 82 increases toward the necessary regenerative braking force.

On the other hand, in the friction brake system 1, when the brake pedal 2 is depressed, the negative pressure booster 3 operates like the conventional negative pressure booster, and the pedal depression force is boosted and output by a predetermined servo ratio. M / C4 generates an M / C pressure based on the pedal effort. The M / C pressures correspond to the corresponding passages 5, 6, the first and second electromagnetic on-off valves 41, 43, the first to fourth branch passages 5a,
It is supplied to each W / C 7, 8, 9, 10 via 5b, 6a, 6b and first to fourth pressure increasing valves 44, 45, 55, 56.

At this time, the M / C pressure signal of the M / C pressure detected by the M / C pressure sensor 69 is input to the pedal depression force calculation unit 73 of the ECU 40, and the pedal depression force calculation unit 73 is based on the M / C pressure signal. The pedal effort is calculated and a pedal effort signal is output. Then, the required total brake force calculation unit 74 calculates the total brake force required (that is, the total brake force requested by the driver by depressing the brake pedal) based on the pedal depression signal, and outputs the total brake force signal. Output. Further, the required friction brake force calculation unit 78 calculates a necessary friction brake force based on the total brake force signal and the regenerative brake force signal from the necessary regenerative brake force calculation unit 76, and outputs a friction brake force signal. Then, the brake fluid pressure control signal output unit 79 generates the brake fluid pressure control solenoid valves (first to fourth pressure increasing valves 44, 45, 55) so as to obtain a necessary friction brake force based on the friction brake force signal. , 56 and first to fourth pressure reducing valves 49, 52,
60, 63).

That is, the ECU 40 first controls opening and closing of the first to fourth pressure increasing valves 44, 45, 55, and 56 by, for example, PMW control (duty control). Then, the brake fluid from the M / C 4 is supplied to each W / C 7, 8, 9, 10 while the flow rate is controlled, and the W / C pressure of each W / C 7, 8, 9, 10 is controlled to increase. Therefore, the regenerative brake force and the friction brake force are coordinated during the normal brake operation to obtain a combined brake force.

Even if the combined braking force reaches the above-mentioned necessary total braking force, the regenerative braking force still increases until reaching the above-described necessary regenerative braking force, so the combined braking force tries to exceed the necessary total braking force. Therefore, the ECU 40 closes the first to fourth pressure increase valves 44, 45, 55, and 56 in order to reduce the friction brake force to obtain the necessary friction brake force as described above and to obtain the total brake force as the combined brake force. At the same time, the first to fourth pressure reducing valves 49, 52, 60, 63 are opened. Then, the brake fluids of the respective W / C 7, 8, 9, 10 correspond to the first and second discharged brake fluid low pressure accumulators 50, while the fluid amount is reduced to a predetermined amount.
The pressure is controlled so that the W / C pressure of each of the W / Cs 7, 8, 9, and 10 becomes the above-described required W / C pressure. Thereby, the friction brake force is controlled to decrease.

During the pressure reduction control of the W / C pressure, the brake fluid pressure control signal (that is, the brake fluid pressure reduction signal) from the brake fluid pressure control signal output unit 79 is input to the necessary pressure difference calculation unit 80. Then, the necessary pressure difference calculation unit 80 transmits the brake fluid pressure control signal, the variable pressure chamber pressure signal from the variable pressure chamber pressure sensor 38, the constant pressure chamber pressure signal from the constant pressure chamber pressure sensor 39, and the valve spring 26 stored in advance. The required pressure difference is calculated based on the load information and a pressure difference signal is output. The pressure difference control signal output unit 81 opens the pressure difference control valve 37 based on the pressure difference signal to communicate the passage 36, and each of the first and second brake fluid introduction valves 68 and 71 is controlled by, for example, PMW ( (Open / close control) and the like. Thereby, the variable pressure chamber 18 and the constant pressure chamber 17 communicate with each other through the passage 36, and the air in the variable pressure chamber 18 flows to the constant pressure chamber 17. Therefore, since the negative pressure level of the variable pressure chamber 18 increases, the pressure difference between the variable pressure chamber pressure and the constant pressure chamber pressure decreases, and the reaction force by the power piston 19 increases. In addition, each fluid chamber of the M / C 4 is controlled to be communicated and shut off to the first and second accumulators 89 and 90 by opening / closing control of the first and second brake fluid introduction valves 68 and 71. As a result, the advancement of the input shaft 28 is hindered and the W
The fluctuation of the pedal depression force during the pressure reduction control of the / C pressure is suppressed.

When the regenerative braking force becomes a necessary regenerative braking force, the regenerative braking force does not increase thereafter and is maintained at the necessary regenerative braking force. For this reason, the friction brake force does not decrease any more and is maintained at the necessary friction brake force described above. Therefore, when the regenerative brake is operated, the necessary total brake force required by the driver is maintained even if the regenerative brake force increases and becomes a necessary regenerative brake force. Thus, the normal brake by the regenerative cooperative brake is operated with the necessary total braking force.

When the vehicle speed is reduced due to the operation of the normal brake, the regenerative braking force decreases. That is, when the ECU 40 determines that the regenerative braking force is decreasing based on a deceleration signal from a vehicle speed sensor (not shown), the first and second pump units 53 are controlled by driving the motor (M) 66 by, for example, PWM control. 61, and the first to fourth pressure increasing valves 44, 45, 55, 56 are again controlled to open and close by, for example, PMW control, and the first to fourth pressure reducing valves 49, 52, 60, 63 again. Close each. Then, the brake fluid discharged to the first and second discharged brake fluid low-pressure accumulators 50 and 72 is discharged to the branch points A and B by the first and second pump units 53 and 61, and these pump discharge fluid and The brake fluid supplied from the M / C 4 supplied through the non-operating first and second electromagnetic on / off valves 41 and 43 is controlled in flow rate by the on / off control of the first to fourth pressure increasing valves 44, 45, 55 and 56. However, it is supplied to each W / C 7, 8, 9, 10.

As a result, the pressure increase control is again performed so that the W / C pressure of each W / C 7, 8, 9, 10 becomes the required W / C pressure, and the friction brake force increases. Thus, the necessary total braking force corresponding to the pedal depression force is maintained, and the normal braking operation by the regenerative cooperative braking is continued with the necessary total braking force.

When the release operation of the normal brake operation is performed by releasing the brake pedal 2 (depressing the pedal), the negative pressure booster 3 is deactivated as in the conventional negative pressure booster, and the M / C 4 is It becomes inactive and the M / C pressure disappears. Based on the disappearance information of the M / C pressure from the M / C pressure sensor 69, the ECU 40 causes the first and second electromagnetic on-off valves 41 and 43, the first to fourth pressure increasing valves 4.
4, 45, 55, 56 and the first to fourth pressure reducing valves 49, 52, 60, 63 are set to the inoperative state shown in FIG. As a result, the brake fluid of each W / C 7, 8, 9, 10 is discharged to the M / C 4 reservoir 12, the W / C pressure disappears, the friction brake is released, and the regenerative brake is released. Normal brake is released.

  Since the regenerative cooperative brake control in the brake system of this example is substantially the same as the regenerative cooperative brake control described in Patent Document 1, further detailed description is omitted. Further, the H / U 11 in the friction brake system 1 of the brake system of this example includes anti-lock brake control (ABS control), traction control (TCS control), vehicle stability control (ESC control), brake assist control (BA control), It is also possible to perform brake fluid pressure control in automatic brake control or the like. Since these brake fluid pressure controls are also substantially the same as the brake fluid pressure controls described in Patent Document 1, their description will be omitted. Note that the first brake fluid introduction valve 68 and the second brake fluid introduction valve 71 that are not operated in the brake fluid pressure control in the regenerative cooperative brake control are operated in any one of these brake fluid pressure controls.

  According to the negative pressure booster 3 and the friction brake system 1 of the brake system of this example, the pressure difference control valve 37 is opened to control the passage 36 between the variable pressure chamber 18 and the constant pressure chamber 17 during the pressure reduction control of the W / C pressure. To communicate with each other. As a result, the negative pressure level of the variable pressure chamber 18 rises due to the air in the variable pressure chamber 18 flowing to the constant pressure chamber 17, so that the pressure difference between the variable pressure chamber pressure and the constant pressure chamber pressure is reduced, and the reaction force generated by the power piston 19. It is possible to prevent the input shaft 28 from moving forward. Therefore, it is possible to effectively suppress fluctuations in the pedal depression force during the pressure reduction control of the W / C pressure in the regenerative cooperative brake operation, and the depression feeling of the brake pedal 2 can be satisfactorily maintained. Note that the pressure difference reduction passage 36 and the pressure difference control valve 37 are not necessarily provided outside the front shell 14 and the rear shell 15, and may be provided, for example, in the valve body 16.

  FIG. 4 is a partially enlarged sectional view partially showing another example of the embodiment of the negative pressure booster according to the present invention. In the following description, the same components as those in the above example are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the negative pressure booster 3 of the above-described example, the vacuum valve 22 and the atmospheric valve 24 have a common valve body 21 and a valve spring 26 and are configured as poppet valves. As shown in FIG. In the negative pressure booster 3, the vacuum valve 22 and the atmospheric valve 24 are individually provided. Further, the negative pressure booster 3 of this example is formed at the atmospheric introduction chamber 83 formed at a predetermined position outside the partition wall 16 a of the valve body 16 and at another predetermined position outside the partition wall 24 of the valve body 16. And a negative pressure introducing chamber 84. The air introduction chamber 83 can be connected to the variable pressure chamber 18, and the negative pressure introduction chamber 84 always communicates with the constant pressure chamber 17 through the air discharge passage 33.

  The atmospheric valve 24 includes an air introduction hole provided in a partition wall 16a of the valve body 16 in which a piston-like atmospheric valve body 24a made of, for example, a rubber seal fixed to the input shaft 28 and a guide hole 20a of the valve plunger 20 are formed. 24b. The atmospheric valve body 24a is fitted into the guide hole 20a in an airtight and slidable manner. The air introduction hole 24b connects the air introduction passage 34 of the valve body 16 and the air introduction chamber 83 through the guide hole 20a.

  Then, when the negative pressure booster 3 in which the brake pedal 2 shown in FIG. 4 is not depressed, the valve body 24a becomes a position facing the atmosphere introduction hole 24b and closes the atmosphere introduction hole 24b. Thereby, the communication between the air introduction passage 34 and the air introduction chamber 83 is blocked. Further, when the brake pedal 2 is depressed and the input shaft 28 moves forward, the valve body 24 a also moves forward relative to the valve body 16. As a result, the valve body 24a is detached from the position facing the air introduction hole 24b and opens the air introduction hole 24b. Therefore, the atmosphere introduction passage 34 and the atmosphere introduction chamber 83 communicate with each other through the guide hole 20a.

  Further, the vacuum valve 22 is constituted by an electromagnetic switching valve, and communicates the variable pressure chamber 18 to the negative pressure introduction chamber 84 through a passage 85 formed in the valve body 16 and is cut off from the atmosphere introduction chamber 83; A second position where the variable pressure chamber 18 communicates with the atmosphere introduction chamber 83 and is blocked from the negative pressure introduction chamber 84, and a third position where the variable pressure chamber 18 is blocked from both the atmosphere introduction chamber 83 and the negative pressure introduction chamber 84. Have. The vacuum valve 22 is assembled to the valve body 16 and connected to the ECU 40.

  The vacuum valve 22 is set to the first position shown in FIG. 4 during normal operation (that is, when it is not operated), and the variable pressure chamber 18 is communicated with the constant pressure chamber 17 and is shut off from the atmosphere introduction chamber 83. When the brake pedal 2 is depressed and the input shaft 28 moves forward, the ECU 40 sets the vacuum valve 22 to the second position based on the stroke signal of the input shaft 28 from the pedal stroke sensor 13 (that is, the pedal stroke signal of the brake pedal 2). Set to position. Therefore, the variable pressure chamber 18 is disconnected from the constant pressure chamber 17 and communicated with the air introduction chamber 83. Further, when the ECU 40 determines that the M / C pressure has become a pressure corresponding to the pedal effort by the M / C pressure signal from the M / C pressure sensor 69, the ECU 40 sets the vacuum valve 22 to the third position. The variable pressure chamber 18 is cut off from both the constant pressure chamber 17 and the air introduction chamber 83. Furthermore, when the depressed brake pedal 2 is released, the ECU 40 sets the vacuum valve 22 to the first position. Therefore, the variable pressure chamber 18 communicates with the constant pressure chamber 17 and is blocked from the air introduction chamber 83.

Thus, in the negative pressure booster 3 of this example, the vacuum valve 22 and the atmospheric valve 24 are separately provided, so that the valve body 21, the vacuum valve seat 23, the atmospheric valve seat 25, and the valve spring of the above example are provided. 26 is not provided. Further, in the negative pressure booster 3 of this example, neither the passage 36 nor the pressure difference control valve 37 is provided. The other configuration of the negative pressure booster 3 in this example is the same as the configuration of the negative pressure booster 3 in the above example.

  In the negative pressure booster 3 of this example, when the brake pedal 2 is depressed and the brake operation is performed from the non-operating state of the negative pressure booster 3 shown in FIG. 4, the negative pressure booster of the above example is performed. As with the device 3, the input shaft 28 advances. Then, the ECU 40 sets the negative pressure valve 22 to the second position by the forward stroke signal of the input shaft 28 from the pedal stroke sensor 13, shuts off the variable pressure chamber 18 from the constant pressure chamber 17, and communicates with the air introduction chamber 83.

  Further, the valve body 24a is advanced by the advance of the input shaft 28 and the atmospheric valve 24 is opened. Then, the atmosphere is introduced into the variable pressure chamber 18 through the atmosphere introduction passage 34, the guide hole 20a, the opened atmosphere valve 24, the atmosphere introduction chamber 83, and the negative pressure valve 22 set at the second position. As a result, the power piston 19 is operated to operate the M / C 4 via the output shaft 29. When the valve body 16 moves forward by the operation of the power piston 19 and the output of the negative pressure booster 3 becomes an output corresponding to the pedal depression force, the atmospheric valve is closed and the ECU 40 sets the negative pressure valve 22 to the third position. As a result, the variable pressure chamber 18 is isolated from both the constant pressure chamber 17 and the atmosphere outside the negative pressure booster 3.

  On the other hand, the ECU 40 operates the regenerative brake 82 in the same manner as the negative pressure booster 3 in the above example. Then, the friction brake force is controlled in consideration of the regenerative brake force so that the total brake force corresponding to the pedal depression force in the brake operation at this time is obtained.

  During the regenerative braking operation, the ECU 40 sets the negative pressure valve 22 to the first position in the same manner as the control of the pressure difference control valve 37 of the negative pressure booster 3 in the above-described example during the pressure reduction control of the friction brake fluid pressure. The pressure difference between the variable pressure chamber 18 and the constant pressure chamber 17 is reduced. As a result, the reaction force from the power piston 19 increases, and it is possible to effectively suppress fluctuations in the pedal effort during pressure reduction control of the friction brake fluid pressure. In particular, since the negative pressure booster 3 of this example does not use the valve spring 26 as in the above-described example, fluctuations in the pedal effort due to the load of the valve spring 26 can be suppressed.

  Other functions and effects of the negative pressure booster 3 of this example and the friction brake system 1 of the brake system including the negative pressure booster 3 are the same as those of the above example. In this example, the negative pressure valve 22 is provided in the shell 14 valve body 16, but it can also be provided outside the front shell 14 and the rear shell 15 like the pressure difference electromagnetic valve 37 in the above example. Of course, in that case, it goes without saying that passages (piping) for connecting the variable pressure chamber 18 to the air introduction chamber 83 and the negative pressure introduction chamber 84 are also provided outside the front shell 14 and the rear shell 15. In this example, the negative pressure valve 22 performs the function of the pressure difference electromagnetic valve 37 in the above example. However, the negative pressure valve 22 is a pressure difference electromagnetic valve similar to the pressure difference electromagnetic valve 37 in the above example. It can also be provided separately.

  The present invention is not limited to the examples described above, and various design changes can be made within the scope described in the claims.

  INDUSTRIAL APPLICABILITY The negative pressure booster and brake system of the present invention can be suitably used for a negative pressure booster that can suppress input fluctuations when a reaction force is interrupted, and a brake system using the negative pressure booster.

DESCRIPTION OF SYMBOLS 1 ... Friction brake system, 2 ... Brake pedal, 3 ... Negative pressure booster, 4 ... Tandem master cylinder (M / C), 5, 6 ... Passage, 7, 8, 9, 10 ... Brake cylinder (W / C) ), 11 ... Brake fluid pressure control device (H / U), 13 ... Pedal stroke sensor (S / U), 14 ... Front shell, 15 ... Rear shell, 16 ... Valve body, 17 ... Constant pressure chamber, 18 ... Transformer chamber, DESCRIPTION OF SYMBOLS 19 ... Power piston, 20 ... Valve plunger, 21 ... Valve body, 22 ... Vacuum valve, 23 ... Vacuum valve seat, 24 ... Atmospheric valve, 25 ... Atmospheric valve seat, 26 ... Valve spring, 28 ... Input shaft, 29 ... Output shaft, 30 ... reaction disk, 32 ... return spring, 36 ... pressure difference reducing passage, 37 ... pressure difference control valve, 38 ... variable pressure chamber pressure sensor, 39 ... constant pressure chamber pressure sensor, 40 ... electronic control unit (EC) U), 44 ... first pressure increasing valve, 45 ... second pressure increasing valve, 49 ... first pressure reducing valve, 50 ... low pressure accumulator for first discharged brake fluid, 52 ... second pressure reducing valve, 53 ... first pump unit, 55 ... 3rd pressure increasing valve, 56 ... 4th pressure increasing valve, 60 ... 3rd pressure reducing valve, 61 ... 2nd pump unit, 63 ... 4th pressure reducing valve, 65 ... W / C pressure sensor, 68 ... 1st brake fluid introduction valve 69 ... M / C pressure sensor, 70 ... passage, 71 ... second brake fluid introduction valve, 72 ... low pressure accumulator for second exhaust brake fluid, 73 ... pedal pedal force calculation unit, 74 ... required total brake force calculation unit, 75 ... regenerative brake necessity determination unit, 76 ... necessary regenerative brake force calculation unit, 77 ... regenerative brake control signal output unit, 78 ... necessary friction brake force calculation unit, 79 ... brake fluid pressure control signal output unit, 80 ... necessary pressure difference Calculation unit, 81 ... Pressure difference control signal Power unit, 83 ... air introducing chamber, 84 ... negative pressure introducing chamber, 85 ... passage, 87 ... first relief valve, 88 ... second relief valve, 89 ... first accumulator, 90 ... second accumulator

Claims (7)

A front shell and a rear shell forming an internal space;
A valve body penetrating the rear shell in an airtight and slidable manner;
The internal space of the valve body attached to the valve body is hermetically divided into a constant pressure chamber connected to a negative pressure source and a variable pressure chamber into which air can be introduced, and operates with a pressure difference between the variable pressure chamber and the constant pressure chamber. And a power piston that generates output,
Communication between the variable pressure chamber and the constant pressure chamber, a vacuum valve for controlling the shutoff;
Communication between the variable pressure chamber and the outside atmosphere, an atmospheric valve for controlling the shutoff;
An input shaft that moves forward by operation of the operation member and moves backward by operation release of the operation member to control the operation of the vacuum valve and the atmospheric valve;
A valve plunger that is actuated and controlled by movement of the input shaft;
An output shaft for outputting the output generated by the power piston to the outside;
A reaction force mechanism for transmitting a reaction force corresponding to the output from the output shaft to the input shaft via the valve plunger;
Characterized in that it comprises at least input fluctuation suppression means for reducing a pressure difference between the variable pressure chamber pressure of the variable pressure chamber and the constant pressure chamber pressure of the constant pressure chamber when the reaction force is interrupted during operation to suppress input fluctuation. Negative pressure booster.   The input fluctuation suppressing means includes a pressure difference reducing passage that bypasses the vacuum valve and connects the variable pressure chamber and the constant pressure chamber, and is normally closed and disposed in the pressure difference reducing passage, and the reaction force The negative pressure booster according to claim 1, further comprising a pressure difference control valve that is opened when the valve is shut off.   The negative pressure booster according to claim 2, wherein both the pressure difference reducing passage and the pressure difference control valve are provided outside the front shell and the rear shell. A front shell and a rear shell forming an internal space;
A valve body penetrating the rear shell in an airtight and slidable manner;
The internal space of the valve body attached to the valve body is hermetically divided into a constant pressure chamber connected to a negative pressure source and a variable pressure chamber into which air can be introduced, and operates with a pressure difference between the variable pressure chamber and the constant pressure chamber. And a power piston that generates output,
Communication between the variable pressure chamber and the constant pressure chamber, a vacuum valve for controlling the shutoff;
Communication between the variable pressure chamber and the outside atmosphere, an atmospheric valve for controlling the shutoff;
An input shaft that moves forward by operation of the operating member and moves backward by releasing operation of the operating member to control the operation of the atmospheric valve;
An output shaft for outputting the output generated by the power piston to the outside;
A reaction force mechanism that transmits a reaction force according to the output from the output shaft to the input shaft;
At least an input fluctuation suppression means for reducing a pressure difference between the variable pressure chamber pressure of the variable pressure chamber and the constant pressure chamber pressure of the constant pressure chamber at the time of shutting off the reaction force at the time of operation;
The atmosphere valve includes an atmosphere introduction hole that is provided in the valve body and introduces the atmosphere into the variable pressure chamber, and a piston-like valve body that is fixed to the input shaft and controls the opening and closing of the atmosphere introduction hole.
The negative pressure booster, wherein the input fluctuation suppressing means is constituted by the vacuum valve. A front shell and a rear shell forming an internal space;
A valve body penetrating the rear shell in an airtight and slidable manner;
The internal space of the valve body attached to the valve body is hermetically divided into a constant pressure chamber connected to a negative pressure source and a variable pressure chamber into which air can be introduced, and operates with a pressure difference between the variable pressure chamber and the constant pressure chamber. And a power piston that generates output,
Communication between the variable pressure chamber and the constant pressure chamber, a vacuum valve for controlling the shutoff;
Communication between the variable pressure chamber and the outside atmosphere, an atmospheric valve for controlling the shutoff;
An input shaft that moves forward by operation of the operating member and moves backward by releasing operation of the operating member to control the operation of the atmospheric valve;
An output shaft for outputting the output generated by the power piston to the outside;
A reaction force mechanism that transmits a reaction force according to the output from the output shaft to the input shaft;
At least an input fluctuation suppression means for reducing a pressure difference between the variable pressure chamber pressure of the variable pressure chamber and the constant pressure chamber pressure of the constant pressure chamber at the time of shutting off the reaction force at the time of operation;
The atmosphere valve includes an atmosphere introduction hole that is provided in the valve body and introduces the atmosphere into the variable pressure chamber, and a piston-like valve body that is fixed to the input shaft and controls the opening and closing of the atmosphere introduction hole.
The input fluctuation suppressing means includes a pressure difference reducing passage that bypasses the vacuum valve and connects the variable pressure chamber and the constant pressure chamber, and is normally closed and disposed in the pressure difference reducing passage, and the reaction force A negative pressure booster comprising a pressure difference reducing valve that opens when the valve is shut off.   6. The negative pressure booster according to claim 5, wherein both the pressure difference reducing passage and the pressure difference reducing valve are provided outside the front shell and the rear shell. A brake operating member;
A negative pressure booster that is operated by operating the brake operating member to boost and output the brake operating force of the brake operating member;
A master cylinder that is actuated by the output of the negative pressure booster to generate brake fluid pressure;
A brake cylinder that generates a braking force by introducing a brake fluid pressure generated in the master cylinder;
A fluid pressure control unit that is disposed in a brake fluid passage between the master cylinder and the brake cylinder and controls a brake fluid pressure introduced into the brake cylinder;
A control unit for controlling the hydraulic pressure control unit,
The negative pressure booster is the negative pressure booster according to any one of claims 1 to 6,
The input fluctuation suppression means of the negative pressure booster is brake operation force fluctuation suppression means for suppressing fluctuations in brake operation force of the brake operation member,
The control unit operates the brake operation force fluctuation suppressing means during the pressure reduction control by the hydraulic pressure control unit of the brake hydraulic pressure introduced into the brake cylinder when the negative pressure booster is operated, and A brake system, characterized in that a pressure difference between a variable pressure chamber pressure and a constant pressure chamber pressure of the constant pressure chamber is reduced.

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