JPH032441Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Field of Application] The present invention relates to a vehicle brake system in which the input/output characteristics of a pneumatic booster (hereinafter referred to as a booster) can be changed. [Prior Art] Conventionally, a vehicle brake system is known that uses a booster to double the depression force on the brake pedal by utilizing the negative pressure in the intake pipe of the engine and transmit it to the master cylinder. The booster used in this vehicle brake system introduces negative pressure into the front constant pressure chamber of the power piston, which is displaceably provided in the shell body via a diaphragm, and introduces atmospheric pressure into the rear working pressure chamber. Thrust is generated in the power piston by the differential pressure between the constant pressure chamber and the working pressure chamber, and the thrust is transmitted to the output shaft installed in the power piston, and this output shaft operates the master cylinder. At this time, the accompanying reaction force is transmitted to the input shaft via a reaction force mechanism consisting of the output shaft, a reaction disk provided on the power piston, and a plunger, and further transmitted to the brake pedal connected to this input shaft. It is something. The reaction force transmitted to the brake pedal is determined by the so-called boost ratio determined by the diameter of the diaphragm, the diameter of the flange provided on the rear side (reaction disk side) of the output shaft, and the diameter of the end of the plunger on the rear side of the reaction disk. Depends on it. By the way, it is desirable that the deceleration of the vehicle during braking always has a constant relationship to the driver's pedal effort.
In other words, even if the weight of the vehicle changes due to people getting on and off the vehicle, there is a need for a brake system that can obtain the braking force that corresponds to the change in conditions with the same brake pedal force as before the weight changes. Although conventional brake devices can change the area ratio of the reaction disk before being installed on the vehicle as described above, they cannot respond in any way to changes in the weight of the vehicle during driving. Ta. [Purpose of the invention] The present invention was made to solve the above problems, and its purpose is to provide a vehicle braking device having a booster whose input/output characteristics can be changed according to predetermined conditions. It is in. [Structure of the invention] The vehicle brake device of the invention includes a second constant pressure chamber and a second working pressure chamber, which are defined by a control piston that can act on an output shaft together with a power piston in a shell body of a booster. A control chamber is provided between the second working pressure chamber and the working pressure chamber, and a switching valve that cuts off communication between the two chambers, and when the switching valve blocks communication between the two chambers. a constant ratio regulator that operates, the constant ratio regulator having a piston portion and a valve portion, pistons having different pressure receiving areas provided in the piston portion, and one of two chambers partitioned by the piston receiving the operating pressure. and the other is connected to the second working pressure chamber of the control chamber, and the second working pressure chamber is connected to the valve portion so that a piston portion generates a pressure difference in the two chambers according to the pressure receiving area. It is characterized in that a valve is provided for selectively connecting the working pressure chamber to a vacuum source and the atmosphere or to the working pressure chamber. [Operation] The vehicle brake device of the present invention exhibits a boosting function by the differential pressure between the constant pressure chamber and the working pressure chamber and the differential pressure between the second constant pressure chamber and the second working pressure chamber of the control chamber. By combining the opening/closing of the switching valve and the operation of the constant ratio regulator, the constant ratio regulator is operated when the switching valve is shut off, and the constant ratio regulator is inactivated when the switching valve is open. It is possible to change the input/output characteristics while adjusting the pressure in the second working pressure chamber. In this case, the constant ratio regulator is provided with pistons with different pressure receiving areas, and by generating a differential pressure according to the difference in the pressure receiving areas and opening/closing the switching valve, the differential pressure between the constant pressure chamber and the working pressure chamber, and the By controlling the ratio of the pressure difference between the two constant pressure chambers and the second working pressure chamber, it is possible to change the ratio of increase in output to increase in input. [Embodiment] Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 4. Reference numeral 1 in FIG. 1 is a main body of a single booster for a vehicle brake, and this main body 1 is composed of a front shell 2 and a rear shell 3. A power piston 4 is provided in the main body 1,
The inside of the main body 1 is defined by the power piston 4 into a first constant pressure chamber (front chamber) A and a first working pressure chamber (rear chamber) B. power piston 4
consists of a diaphragm 5, a piston 6, a piston holder 7, and a valve body 8, and the diaphragm 5
It is displaceably attached to the front shell 2 and rear shell 3 via. The piston 6 is held together with the diaphragm 5 by a piston holder 7 and a valve body 8. The piston holder 7 and the valve body 8 are tightened and fixed with bolts and nuts (not shown), and a control chamber 9 is formed between the piston holder 7 and the valve body 8. A control piston (actuating member) 10 is provided in the control chamber 9, and the control piston 10 defines the inside of the control chamber 9 into a second constant pressure chamber C and a second working pressure chamber D. . The control piston 10 includes a diaphragm 11 and a piston 12, and is displaceably attached to the piston holder 7 and the valve body 8 via the diaphragm 11. A communication hole 13 is formed in the piston holder 7,
The communication hole 13 allows the first constant pressure chamber A and the second constant pressure chamber C to communicate with each other. Further, a protrusion 14 is formed on the front side (left side in FIG. 1) of the piston holder 7, and the protrusion 14 has a passage 1.
5 is formed. This passage 15 communicates with a passage 16 formed in the valve body 8, and via this passage 16 with the second working pressure chamber D. Further, a stepped hole 20 consisting of a large diameter part and a small diameter part is formed in the center of the piston holder 7, and a reaction disk 21 made of an elastic member such as rubber is formed in the large diameter part of the stepped hole 20. A flange 23 formed at the rear end of the output shaft 22 is fitted. A recess 24 is formed in the flange 23, and the reaction disk 21 is fitted into the recess 24. In addition, the rear end of the valve body 8 is connected to the rear shell 3.
It protrudes from the rear shell 3 and is movably supported by the rear shell 3 via the seal member 25. A stepped through hole is formed in the center of the valve body 8 and is located on the same axis as the output shaft 22 and includes a large diameter valve hole 26 and a small diameter cylinder hole 27. A plunger 28 is slidably fitted into the cylinder hole 27. 29 is a seal ring. The end of the plunger 28 on the output shaft 22 side is formed to have a small diameter, and is slidably fitted into the small diameter part of the stepped hole 20 of the piston holder 7. Further, a side portion of the output shaft 22 of the plunger 28 passes through the center portions of the diaphragm 11 and the piston 12 of the control piston 10, and is attached to the diaphragm 11 and the piston 12 by a fixing member 30. A recess 31 is formed at the rear end of the plunger 28, and a spherical portion 33 formed at the tip of an input shaft 32 is fitted into this recess 31. A brake pedal (not shown) (input member) is connected to the rear end of the input shaft 32. The output shaft 22, reaction disk 21, and plunger 28 constitute a reaction force mechanism. Note that valve seats 35 and 36 are formed at the rear end portions of the cylinder member 34 having the cylinder hole portion 27 and the plunger 28, respectively. A poppet valve 37 is slidably provided within the valve hole 26. This poppet valve 3
7 is a valve seat 35 formed at the rear end of the cylinder portion 34, which is biased toward the plunger 28 by a spring 40 provided between a spring receiver 38 provided on the input shaft 32 and a spring receiver 39 of the poppet valve 37.
and a valve seat 36 formed at the rear end of the plunger 28, and when the brake pedal is not depressed, these valve seats 35,
36. Furthermore, a passage 41 is formed in the piston holder 7 and the valve body 8 , one end of which opens into the first constant pressure chamber A, and the other end of which opens at the rear end of the cylinder portion 34 . Poppet valve 3 of this passage 41
The 7 side opening can be opened and closed by this poppet valve 37. In addition, the valve body 8 has
A passage 42 is formed that opens into the first working pressure chamber B at one end and opens into the cylinder hole 27 at the other end. In FIG. 1, 44 is an air cleaner, and 45 is a silencer. It should be noted that in the non-operating state, a predetermined gap 46 is provided between the rear surface of the reaction disk 21 and the front side surface of the plunger 28. Also, front shell 2 and power piston 4
A return spring 47 is provided between the power piston 4 and the power piston 4 to urge the power piston 4 rearward.
Further, the front shell 2 is provided with a connection port 48 communicating with the first constant pressure chamber A and a connection port 49 communicating with the passage 15. The inside of the connection port 49 and the passage 15 are isolated from the first constant pressure chamber A by a retractable seal member 43. The rear shell 3 is provided with a connection port 50 that communicates with the first working pressure chamber B. Connection port 48 is connected to a vacuum source (not shown) and is also connected to control valve 51 . The connection ports 48 and 50 are each connected to a control valve 51. A controller 52 is connected to this control valve 51. As shown in FIG. 2, the control valve 51 includes constant ratio regulators 53, 54, electromagnetic valves (switching valves) 55, 56, 57, 58, 59, 60.
It is made up of The constant ratio regulator 53 consists of a piston part 53a and a valve part 53b, and has connection ports 61, 62, 63,
64 and 65 and a valve seat 66 formed therein, a large piston 69 having a diaphragm 68 and displaceable inside the housing 67 via the diaphragm 68, and a diaphragm 70. A small piston 71 is displaceably provided in the housing 67 via the diaphragm 70, and the large piston 69 and small piston 71 are connected to each other, and a valve seat 72 is attached to the flange at the tip.
A rod 73 is formed with a valve seat 74 on one side.
a poppet valve 75 which has a diaphragm 75a on the other side, is displaceably provided in the housing 67 via the diaphragm 75a, and is capable of approaching and separating from the valve seat 66;
a spring 7 provided to bias the valve seat 66 toward the valve seat 66;
It consists of 6. Inside the housing 67, a large piston 69, a small piston 71, and a poppet valve 75 form a plurality of chambers E (valve front chamber), F ₁ ,
It is defined by G ₁ (valvular chamber), H ₁ and I ₁ . The constant ratio regulator 54 is the constant ratio regulator 5
3, the piston portion 54a
and a valve part 54b, and connection ports 77, 78, 7
9, 80, 81 and a valve seat 82 formed therein; a large piston 85 having a diaphragm 84; a small piston 87 having a diaphragm 86; It consists of a rod 89 having a valve seat 88, a valve seat 90, a poppet valve 91 having a diaphragm 91a, and a spring 92. Inside the housing 83, a large piston 85, a small piston 87, and a poppet valve 91 form a plurality of chambers.
E ₂ (valve front chamber), F ₂ , G ₂ (valve rear chamber), H ₂ , I ₂
It is defined in In addition, the connection ports 61 and 6 of the constant ratio regulator 53
4 are each connected to an electromagnetic valve 60 by piping, and the electromagnetic valve 60 is connected to a connection port 50 provided in the rear shell 3. The connection port 65 is connected to the electromagnetic valve 59 via piping. The connection ports 62 and 63 are connected to connection ports 78 and 79 of the constant ratio regulator 54, respectively, by piping. Further, the connection port 77 of the constant ratio regulator 54 is connected to the electromagnetic valve 56, and the connection port 80 is connected to the electromagnetic valve 58 by piping. Connection port 81
is connected to an electromagnetic valve 57 by piping, and the electromagnetic valve 56 is connected to electromagnetic valves 57 and 60 and a connection port 50 provided in the rear shell 3 by piping. The connection port 78 is connected to the electromagnetic valves 55 and 58 and the connection port 48 provided in the front shell 2 by piping. The connection port 79 is connected to the electromagnetic valves 55 and 56 and the connection port 49 provided in the front shell 2 by piping. In addition, each electromagnetic valve 55, 56, 57, 58, 59, 60
are electrically connected to the controller 52, respectively. Predetermined input signals 100 such as a vehicle speed signal J, an accelerator state signal K, a handbrake state signal L, and a vehicle weight detection signal M are input to the control 52. And the controller 52
is adapted to control the control valve 51 when these input signals satisfy predetermined conditions. Next, the effect will be explained. Until now, in order to obtain appropriate braking force when the weight of the vehicle changes due to an increase in the number of passengers or an increase or decrease in the load capacity, the driver has to control the force on the brake pedal. It would be truly advantageous if it were possible to automatically obtain an appropriate braking force according to the weight of the vehicle through normal brake operation without the need for pedal force control. Therefore, in this embodiment, a constant specific pressure with respect to the differential pressure between the first constant pressure chamber A and the first working pressure chamber B of the power piston, which is generated by stepping on the brake pedal, is set to a constant pressure between the second constant pressure chamber and the first working pressure chamber B. The input and output characteristics of the booster are changed by controlling the control valve 52 so as to generate the pressure in the working pressure chamber D of No. 2,
During normal brake operation, higher output is gradually obtained as the vehicle weight increases. That is,
When the vehicle weight detection signal M is input to the controller 52 when the vehicle speed signal J, accelerator state signal K, handbrake state signal L, etc. satisfy predetermined conditions and the brake pedal is not depressed, the controller 52 control valve 51
is controlled as shown in Table 1.

[Effect of idea]

As explained above, according to the present invention, the pressure in the second operating pressure chamber in the control chamber is controlled by opening/closing the switching valve and operating the constant ratio regulator. Input/output characteristics can be changed. In this case, since the constant ratio regulator is provided with pistons with different pressure receiving areas, the generation of differential pressure according to the pressure receiving areas and the opening and closing of the switching valve causes the differential pressure between the constant pressure chamber and the working pressure chamber. By controlling the ratio of the pressure difference between the second constant pressure chamber and the second working pressure chamber, it is possible to change the ratio of increase in output to increase in input. It is also possible to change the ratio of Therefore, even if the weight of the vehicle changes due to people getting on and off, for example, the greater the weight, the higher the ratio of increase in output to input, and the normal force applied to the brake pedal will compensate for this change in vehicle weight. You can obtain the appropriate braking force according to your needs.

[Brief explanation of the drawing]

Figure 1 is a side cross-sectional view of a booster showing an embodiment of the present invention, with a piping diagram and electric circuit diagram added, and Figure 2 is a pneumatic circuit diagram and electric circuit diagram showing the relationship between the control valve and the controller. Figure 3 shows the booster's first constant pressure chamber and second constant pressure chamber.
The second constant pressure chamber and the second
A pressure difference characteristic diagram showing the relationship between the pressure difference and the working pressure chamber of
FIG. 4 is an input/output characteristic diagram of the booster. 1...Body, 4...Power piston, 5,1
1, 68, 70, 84, 86... diaphragm,
6, 12... Piston, 9... Control chamber, 10... Control piston (operating member), 21... Reaction disk, 22...
Output shaft, 32... Input shaft, 37, 75, 91...
Poppet valve, 51...control valve,
53a, 54a... Piston part, 53, 54...
Constant ratio regulator, 53b, 54b...valve part, 5
5, 56, 57, 58, 59, 60... Solenoid valve, A... First constant pressure chamber (front chamber), B...
First working pressure chamber (rear chamber), E ₁ , E ₂ ... chamber (valve front chamber), G ₁ , G ₂ ... chamber (valve rear chamber).

Claims (1)

[Claims for Utility Model Registration] An operation in which a power piston having a diaphragm and provided in the shell body applies a predetermined operating pressure to a constant pressure chamber connected to a vacuum source within the shell body through the diaphragm. A valve mechanism is provided in the power piston to control the pressure of the operating pressure chamber in conjunction with an input member, and the input member is actuated to control the pressure between the two chambers. A vehicle using a pneumatic booster which transmits the thrust force acting on the power piston to the output shaft and the reaction force acting on the output shaft to the input member when a pressure difference is generated between the power piston and the power piston. In the brake device, a control chamber having a second constant pressure chamber and a second working pressure chamber defined by a control piston capable of exerting a thrust on the output shaft together with the power piston is provided in the shell main body, A switching valve that disconnects communication between the two chambers and a constant ratio regulator that operates when the switching valve disconnects communication between the two chambers is provided between the two operating pressure chambers and the operating pressure chamber, The constant ratio regulator has a piston part and a valve part, and pistons with different pressure receiving areas are provided in the piston part, and one of the two chambers partitioned by the piston is the working pressure chamber, and the other is the control chamber. The valve portion is connected to the second working pressure chamber, and the second working pressure chamber is connected to a vacuum source and the atmosphere so that the piston portion generates a pressure difference in the two chambers according to the pressure receiving area. Alternatively, a vehicle brake device characterized in that a valve is provided which is selectively connected to the operating pressure chamber.