JP4512933B2 - Hydraulic brake device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a hydraulic brake device that enables boost control and automatic brake control.
[0002]
[Prior art]
About conventional hydraulic brake equipment for automobilesTenAnd figure11Will be described with reference to FIG. FigureTo 10The hydraulic brake device 1 shown is an example in which an automatic brake operation function is provided with the simplest configuration. FigureTen, A large-diameter piston 3 is slidably fitted in the master cylinder 2, and a small-diameter rod portion 4 integrally connected to the piston 3 is extended to the outside so that the inside of the master cylinder 2 Two chambers of a pressurizing chamber 5 and a pressure adding chamber 6 are formed. A brake pedal 7 is connected to the rod portion 4, and a return spring 8 is provided in the pressurizing chamber 5.
[0003]
The pressurizing chamber 5 is connected to the wheel cylinder 9 and is connected to the reservoir 11 via the reservoir port 10. The pressure adding chamber 6 is connected to the reservoir 11 via the pump 12 and is pressurized by the discharge pressure of the pump 12. An electromagnetic pressure control valve 13 is provided in parallel with the pump 12 between the pressure addition chamber 6 and the reservoir 11.
[0004]
Next, the operation of the hydraulic brake device 1 will be described. In the case of operating force only by a normal driver, the brake pedal 7 is depressed with the operating force F, and the spring force F of the return spring 8_kWhen the piston 3 moves forward against this, the reservoir port 10 is closed, the pressurizing chamber 5 is pressurized, and the pressure acts on the wheel cylinder 9. At this time, the pressure P of the pressure chamber 5_aIs the pressure receiving area of the piston 3 against the pressurizing chamber 5_aThen,
P_a= (F−F_k) / S_a
It becomes.
[0005]
In the case of automatic brake control without operation by the driver, the pump 12 is activated, the pressure adding chamber 6 is pressurized, the piston 3 is advanced against the spring force of the return spring 8, and the pressure chamber 5 is pressurized. . The pressure in the pressure adding chamber 6 is controlled by adjusting the discharge pressure of the pump 12 by the electromagnetic pressure control valve 13. At this time, the pressure P of the pressure chamber 5_aIs the effective pressure receiving area for the pressure addition chamber 6 of the piston 3 S_c, Pump 12 discharge pressure P_cThen
P_a= (S_c× P_c−F_k) / S_a
It becomes.
[0006]
If the driver's operating force and the automatic braking operation force act simultaneously, add these,
P_a= (F + S_c× P_c−F_k) / S_a
It can be. Alternatively, the pressure in the pressurization chamber 5 is detected by a pressure sensor, or the vehicle deceleration is detected by an acceleration sensor, and the discharge pressure of the pump 12 is adjusted so as not to exceed the target pressure or target deceleration by automatic braking. Thus, by supplying the wheel cylinder 9 with the required pressure that is greater by the driver's operating force or by the automatic brake, the driver's uncomfortable feeling of brake operation can be reduced.
[0007]
In addition, the pressure in both the pressurizing chamber 5 and the pressure adding chamber 6 is detected by a pressure sensor,
F = S_a× P_a−S_c× P_c+ F_k
To calculate the operating force F, and the boost ratio is α,
P_a= Α x F / S_a
The discharge pressure of the pump 12 is adjusted by the electromagnetic pressure control valve 13 so that the pressure P in the pressure adding chamber 6_cIt is also possible to perform boost control by controlling.
[0008]
However, when performing boost control in this way, it is necessary to use two expensive pressure sensors, and the operating force F is calculated based on the outputs of the two pressure sensors, so accuracy can be improved. With the problem of being difficult.
[0009]
  On the other hand, the hydraulic brake device for automobiles shown in FIG. 11 is an example that enables boost control with a simple structure. Note that portions similar to those illustrated in FIG. 10 are described with the same reference numerals. Referring to FIG. 11, a stepped piston 17 having a small diameter portion 15 and a large diameter portion 16 is slidably fitted in the master cylinder 14 to form two chambers, a pressurizing chamber 18 and a supply chamber 19. Has been. A rod portion 20 is connected to the piston 17 and extends to the outside of the master cylinder 14, and the brake pedal 7 is connected to the rod portion 20.CommunicatingIt is tied. A return spring 8 is provided in the pressurizing chamber 18.
[0010]
The pressurizing chamber 18 is connected to the wheel cylinder 9 and communicates with the supply chamber 19 through the port 21. The supply chamber 19 is connected to the reservoir 11 via the reservoir port 22. The supply chamber 19 is connected to the suction side of the pump 23, and the discharge side of the pump 23 is connected to the wheel cylinder 9. The suction side and the discharge side of the pump 23 are connected via a pilot-type pressure control valve 24. The pressure control valve 24 is closed when the pressure on the suction side of the pump 23, that is, the supply chamber 19, is substantially higher than 0, and is opened when the pressure is low.
[0011]
Next, the operation of the hydraulic brake device 14 will be described. When the brake pedal 7 is depressed with the operating force F, the spring force F of the return spring 8_kWhen the piston 17 moves forward against this, the port 21 and the reservoir port 22 are closed, and a closed space is formed by the pressurizing chamber 18, the supply chamber 19 and the wheel cylinder 9, and thereafter, according to the stroke of the piston 17 Thus, the amount of liquid supplied to the wheel cylinder 9 is determined.
[0012]
As the piston 17 advances, the pressurizing chamber 18 and the supply chamber 19 are pressurized, and the brake fluid is supplied to the wheel cylinder 9. At the same time, the brake fluid is supplied from the supply chamber 19 to the pressurizing chamber 18 by the activation of the pump 23. Supplied. At this time, the effective pressure receiving area for the pressurizing chamber 18 of the small diameter portion 15 of the piston 17 is S._aThe effective pressure receiving area for the supply chamber 19 of the large diameter portion 16 is S_b, The pressure in the pressurizing chamber 18 is P_a, Supply chamber 19 pressure P_bThen, the following equation is established from the balance of forces acting on the piston 17.
F = S_a× P_a+ S_b× P_b+ F_k  ▲ 1 ▼
[0013]
Here, in the supply chamber 19, when the pressure becomes positive, the pressure control valve 24 is closed and the pressure is reduced by suction of the pump 23, and when the pressure becomes almost 0, the pressure control valve 24 is opened and the pump 23 Is unloaded, so its pressure is almost zero. Therefore, in equation (1), P_b= 0, pressure P in the pressure chamber 18_aIs
P_a= (F−F_k) / S_a
It becomes. On the other hand, the pressure P in the pressurizing chamber 18 when the wheel cylinder 9 is directly pressurized by the piston 17 without the pump 23 and the pressure control valve 24._a´ is
P_a´ ＝ (F−F_k) / (S_a+ S_b)
Therefore, the boost ratio α is
α = P_a/ P_a´ ＝ (S_a+ S_b) / S_a
Thus, boost control can be performed. Note that the amount of brake fluid supplied to the wheel cylinder 9 is as follows:
(S_a+ S_b) × L
It is. A brake system that performs boost control in this way is described, for example, in German Patent No. 19716404.
[0014]
[Problems to be solved by the invention]
However, the figure11 toIn the conventional example shown, the pressurizing chamber 18 and the supply chamber 19 are both in communication with the reservoir 11 during non-braking (when the driver's operating force is not acting on the brake pedal 7), and the piston is connected to the piston by the pump. Since thrust cannot be applied, there is a problem that automatic brake control such as traction control cannot be performed.
[0015]
The present invention has been made in view of the above points, and an object thereof is to provide a hydraulic brake device capable of performing boost control and automatic brake control with a simple structure.
[0016]
[Means for Solving the Problems]
  To solve the above problem,The present inventionThe hydraulic brake device ofA stepped piston having a small-diameter portion and a large-diameter portion, a pressurizing chamber that is pressurized by the small-diameter portion by the advancement of the piston and connected to a wheel cylinder through a first conduit, A master cylinder having a supply chamber pressurized by a diameter portion, and a pressure addition chamber formed on the piston retreat side of the large diameter portion and connected to the wheel cylinder via a second pipe line;
  An on-off valve provided in the second pipeline;
A pump having a suction side connected to the supply chamber and a discharge side connected between the pressure adding chamber of the second pipe line and the on-off valve;
  Provided between the suction side of the pump and a third pipe connected to the first pipe, and communicates the suction side of the pump and the third pipe based on the pressure in the supply chamber A pressure control valve for shutting off,
  An effective pressure receiving area of the piston with respect to the pressurizing chamber is larger than an effective pressure receiving area with respect to the pressure adding chamber;
  The pressure control valve closes the third conduit when the pressure in the supply chamber is positive, and connects the third conduit to the suction side of the pump when the pressure in the supply chamber is negative. Communicate with
The pump is configured to reduce the pressure of the supply chamber, which becomes positive pressure as the piston moves forward, to approach 0 by suction..
  With this configuration, it is possible to perform boost control by pressurizing the pressurizing chamber and the pressure adding chamber connected to the wheel cylinder by a pump according to the operating force on the piston. The boost ratio is determined by the difference between the effective pressure receiving area for the chamber and the effective pressure receiving area for the pressure adding chamber.Also,When the on-off valve is closed, the pressure in the pressure adding chamber becomes higher than the pressure in the pressurizing chamber due to the pressurization of the pump, and the piston moves forward and the automatic brake operates..
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the hydraulic brake device 25 of the first embodiment includes a stepped piston having a small-diameter portion 27 at the distal end, a large-diameter portion 28 at the center, and a rod portion 29 at the proximal end in the master cylinder 26. 30 is slidably fitted to form a pressurizing chamber 31, a supply chamber 32, and a pressure adding chamber 33. The rod portion 29 has a diameter larger than that of the small diameter portion 27 and a diameter smaller than that of the large diameter portion 28, and a brake pedal 34 is connected to an end portion extending to the outside of the master cylinder 26. Effective pressure receiving area S for the pressurizing chamber 31 of the small diameter portion 27 of the piston 30_aEffective pressure receiving area S for supply chamber 32 of large diameter portion 28_bAnd effective pressure receiving area S for pressure adding chamber 33 of large diameter portion 28_cThe relationship is S_a> S_cAnd S_b> S_cIt has become. A return spring 35 is provided in the pressurizing chamber 31.
[0018]
  The pressurizing chamber 31 is connected to the reservoir R via the reservoir port 36. The reservoir port 36 is arranged so that it opens when the piston 30 is in the non-braking position, and is closed by the small-diameter portion 27 when braking is started and the piston 30 moves forward. The pressurizing chamber 31 is provided with a pipe line 37.(First pipeline)It is connected to the wheel cylinder 38 via.
[0019]
  The pressure adding chamber 33 is connected to a pipeline 39.(Second pipe)It is connected to the wheel cylinder 38 via. A proportional electromagnetic valve 40 (open / close valve) is provided in the pipe line 39. The proportional solenoid valve 40 is a normally open solenoid valve having a poppet structure provided with a push-type linear solenoid, and its opening degree can be adjusted according to the energization current.
[0020]
  The supply chamber 32 is connected to the suction side of the pump 41 via the pressure control valve 42, and the discharge side of the pump 41 is connected between the pressure addition chamber 33 and the proportional solenoid valve 40 in the conduit 39. The pump 41 is normally stopped and is started in conjunction with the operation of the brake pedal 34 or the operation of an automatic brake described later. Pressure control valve 42 is connected to line 43(Third pipeline)To the reservoir 37, and to the reservoir R by the conduit 44. The pressure control valve 42 is a spool-type pilot type pressure control valve. When the pressure in the supply chamber 32 and the reservoir R is introduced and the pressure in the supply chamber 32 is positive, the pipe 43 is closed. The brake fluid on the supply chamber 32 side is discharged by the pump 41 to the pipeline 39 side,32When the pressure is negative, the pressure in the supply chamber 32 is kept almost zero by connecting the pipe 43 to the suction side of the pump 41 and unloading the pump 41.(Adjusted to approach 0). The pressure control valve 42 may be of any other type as long as it has the above function, for example, a poppet type having a differential pressure detection piston.
[0021]
Next, the operation of the present embodiment configured as described above will be described. Normally, the proportional solenoid valve 40 is fully opened. The brake pedal 34 is depressed with the operating force F, and the spring force F of the return spring 35_kWhen the piston 30 moves forward against this, the reservoir port 36 is closed by the small diameter portion 27. When the pump 41 is started, the proportional solenoid valve 40 is opened, so that the pressurizing chamber 31, the wheel cylinder 38, and the pressure adding chamber 33 are equally applied by the discharge pressure of the pump 41 through the conduit 39 and the conduit 37. Pressed.
[0022]
  At this time, the pressure in the pressurizing chamber 31 is P_a, Supply chamber 32 pressure P_b, P in the pressure adding chamber 33_cThen, the following equation is established from the balance of forces acting on the piston 30.
  F = S_a× P_a+ S_b× P_b−S_c× P_c+ F_k  (2)
Here, the supply chamber 32 is depressurized by suction of the pump 23 because the pressure control valve 42 closes the conduit 43 when the pressure becomes positive, and when the pressure becomes almost zero, the pressure control valve 42 is Since the passage 41 is communicated with the suction side and the pump 41 is unloaded, the pressure becomes almost zero. Further, the pump 41 pressurizes the pressurizing chamber 31 and the pressure adding chamber 33 equally. Therefore, in equation (2), P_b= 0, P_a= P_cThen,
  P_a= (F−F_k) / (S_a−S_c)
It becomes. On the other hand, pump 41ThePressure P of the pressure chamber 31 when the wheel cylinder 38 is directly pressurized by the piston 30 without being operated._a´ is P_a= P_b= P_cFrom
  P_a´ ＝ (F−F_k) / (S_a+ S_b−S_c)
Therefore, the boost ratio α is
  α = P_a/ P_a´ ＝ (S_a+ S_b−S_c) / (S_a−S_c)
Thus, boost control can be performed. At this time, the reaction force F to the brake pedal 34 is
  F = (S_a−S_c) × P_a+ F_k
It becomes. Also, the amount of brake fluid supplied to the wheel cylinder 38 is as follows:
  (S_a+ S_b−S_c) × L
And S_a+ S_b−S_cIs equal to the cross-sectional area of the rod portion 29 of the piston 30. Even when the boosting function is lost due to a failure of the pump 41 or the like, the pressure P is increased by the cooperation of the pressurizing chamber 31, the supply chamber 32, and the pressure adding chamber 33._aSince 'is obtained, the braking force can be secured.
[0023]
Next, the operation of the automatic brake will be described. When operating as an automatic brake, the pump 41 is started, the proportional solenoid valve 40 is semi-closed, and the pressure adding chamber 33 is pressurized. Pressure P in pressure adding chamber 33_cRises and S_c× P_c> F_kThe piston 30 advances and closes the reservoir port 36. Thereafter, as in the case of the boost control, the operation of the pump 41 and the pressure control valve 42 causes P to_b= 0, so the pressure P in the pressurizing chamber 31_aIs
P_a= (S_c× P_c−F_k) / S_a
It becomes. The differential current between pressure adding chamber 33 and pressurizing chamber 31
ΔP = P_c−P_a= (S_a/ S_c−1) × P_a+ F_k/ S_c
If the current value corresponds to the target wheel cylinder pressure P_aIs obtained. S_a> S_cΔP is always positive and the wheel cylinder pressure P_aIs a constant of 1 / (S for the increase in the current flowing to the proportional solenoid valve 40._a/ S_c-1) linearly increases. At this time, the amount of brake fluid supplied to the wheel cylinder 38 is the same as that during the boost control.
[0024]
Since brake fluid is supplied from the supply chamber 32 to the pressure adding chamber 33 when the automatic brake is operated, in order to control in the same way as during the boost control, S_b> S_cIt is desirable that the pressure control valve 42 is connected to the pressure P in the supply chamber 32._bIf it is configured so that the brake fluid flows from the pressurizing chamber 31 side to the supply chamber 32 side when S is 0, S_b<S_cHowever, the pressure adding chamber 33 can be pressurized.
[0025]
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the master cylinder is tandemd into two systems with respect to the first embodiment, and two wheel cylinders are provided in each system. Henceforth, the same as the first embodiment described above. The parts are denoted by the same reference numerals, and only different parts will be described in detail.
[0026]
As shown in FIG. 2, in the hydraulic brake device 45 of the second embodiment, the master cylinder 46 is tandemly inserted with the secondary piston 47 and its return spring 48 to form a second pressurizing chamber 49. ing. The second pressurizing chamber 49 is connected to the reservoir R via the reservoir port 50, and the second pressurizing chamber 49 is connected to the two wheel cylinders 52 via the conduit 51.
[0027]
The piston 30 has an effective pressure receiving area S for the supply chamber 32 of the large diameter portion 28._bAnd effective pressure receiving area S for pressure adding chamber 33_cAre equal and S_a+ S_b−S_c= S_aIt is supposed to be. The secondary piston 47 has the same diameter as the small diameter portion 27 of the piston 30 (primary piston).
[0028]
With this configuration, when the pressurizing chamber 31 is pressurized, the second pressurizing chamber 49 is also pressurized through the secondary piston 47, and the wheel cylinder 52 is applied in the same manner as the wheel cylinder 38. Pressure is generated to generate braking force. At this time, since the small diameter portion 27 of the piston 30 and the secondary piston 47 have the same diameter, the discharge amounts of the pressurizing chamber 31 and the second pressurizing chamber 49 become equal. Further, the step of the cylinder part is reduced, and processing and assembly can be easily performed. If different discharge volumes are required on the primary and secondary sides, S_b<S_cAs described above, by increasing the diameter of the rod portion 29, the discharge amount on the primary side can be increased.
[0029]
Next, a third embodiment of the present invention will be described with reference to FIG. In addition, since the third embodiment is provided with two wheel cylinders and further provided with an ABS (anti-lock brake system) with respect to the first embodiment, the same as the first embodiment below. These parts are denoted by the same reference numerals and only different parts will be described in detail.
[0030]
  As shown in FIG. 3, in the hydraulic brake device 53 of the third embodiment, two wheel cylinders 38 are connected to a pipe line 37 communicating with the pressurizing chamber 31. In each pipe line 37, there are a pressure increase valve 54 (normally open electromagnetic on-off valve) and a check valve 55 that allows only the flow from the pressurizing chamber 31 side to the wheel cylinder side for each wheel cylinder 38. They are arranged in parallel. Each wheel cylinder 38 is connected to an accumulator via a pressure reducing valve 57 (normally closed electromagnetic on-off valve) by a pipe 56.58Connected to the accumulator58Is connected to the suction side of the pump 41 via a check valve 59. The check valve 59 allows only the flow from the accumulator 58 side to the pump 41 side.
[0031]
With this configuration, boost control and automatic brake control can be performed as in the first embodiment.
[0032]
Further, when the ABS is activated, when the braking force generated by the wheel cylinder 38 becomes larger than the frictional force between the road surface tires and the tires are locked, the normally open pressure increasing valve 54 is closed and the normally closed pressure reducing valve 57 is opened. . As a result, the supply of the brake fluid to the wheel cylinder 38 is stopped, the pressurized brake fluid in the wheel cylinder 38 flows out to the accumulator 58, the pressure of the wheel cylinder 38 decreases, and the tire lock is released. Is done. After that, when the pressure reducing valve 57 is closed and the pressure increasing valve 54 is opened, the pump 41 is operated, so that the brake fluid stored in the accumulator 58 is discharged by the pump 41 through the check valve 59, and the wheel cylinder Pressurize 38 again.
[0033]
Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, since the same ABS as that of the third embodiment is incorporated in the second embodiment, the following will be described with respect to the second and third embodiments. The same parts are denoted by the same reference numerals, and only different parts will be described in detail.
[0034]
As shown in FIG. 4, in the hydraulic brake device 60 of the fourth embodiment, a pressure increasing valve 61 (normally open valve) is connected to each wheel cylinder 52 in a pipe line 51 communicating with the second pressurizing chamber 49. An electromagnetic on-off valve) and a check valve 62 that allows only a flow from the second pressurizing chamber 49 side to the wheel cylinder 52 side are arranged in parallel. Each wheel cylinder 52 is connected to an accumulator 65 through a pipe line 63 via a pressure reducing valve 64 (normally closed electromagnetic on-off valve). The accumulator 65 is connected to the suction side of the return pump 67 via a throttle 66. The discharge side of the pump 67 is connected to the pipeline 51 via a check valve 68. The check valve 68 allows only the flow from the pump 67 side to the pipe line 51 side. The pump 67 is provided with a pressure control valve 69 for controlling the discharge amount so that the pressure of the accumulator 65 becomes almost zero when the wheel cylinder 52 is repressurized during ABS operation. The primary side pump 41 and the secondary side pump 67 are driven by a common motor 70. A restrictor 71 provided in the restrictor 66 and the pipe 56 on the primary side is for preventing abrupt movement of the brake fluid from the accumulators 58 and 65 to the suction side of the pumps 41 and 67 during the ABS operation.
[0035]
With this configuration, as in the second and third embodiments, brake fluid can be supplied to the two wheel cylinders to perform boost control, automatic brake control, and antilock brake control. .
[0036]
Next, a fifth embodiment of the present invention will be described with reference to FIG. In the fifth embodiment, the hydraulic brake device of the third embodiment is arranged in parallel to form two systems, so the same reference numerals are used for the same parts as those of the third embodiment. Only the different parts will be described in detail.
[0037]
As shown in FIG. 5, in the hydraulic brake device 72 of the fifth embodiment, two master cylinders 26 similar to those of the third embodiment are arranged in parallel, and guides 73 are arranged on the rod portions 29 of the respective pistons 30. The brake pedal 34 is connected via a lever 74 that is guided so as to be able to move forward and backward by the operation force F, and the operating force F of the brake pedal 34 is divided by half and transmitted to each piston 30. ing. The pumps 41 of each system are driven by a common motor 75.
[0038]
With this configuration, it is possible to perform boost control, automatic brake control, and antilock brake control for the two wheel cylinders as in the third embodiment. At this time, even when one of the systems fails, the necessary braking force can be ensured by the other system.
[0039]
Next, a sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, since the accumulator is incorporated in the piston of the first embodiment, parts similar to those of the first embodiment shown in FIG. Only the part will be described in detail.
[0040]
As shown in FIG. 6, in the hydraulic brake device 76 of the sixth embodiment, an accumulator 77 (pressure accumulating means) is built in the small diameter portion 27 of the piston 30. In the accumulator 77, a free piston 79 is slidably fitted in a cylinder bore 78 formed in the small-diameter portion 27, and the cylinder bore 78 is defined by oil free chambers 78A and 78B by the free piston 79. Yes. The oil chamber 78A is communicated with the supply chamber 32 via the oil passage 80, and the oil chamber 78B is communicated with the reservoir R via the oil passage 81 and the oil passage 82. The free piston 79 is normally in contact with the end of the cylinder bore 78 on the oil chamber 78A side by the spring force of the return spring 83 provided in the oil chamber 78B.
[0041]
With this configuration, boost control and automatic brake control can be performed as in the first embodiment.
In this case, since the pump 41 is started in conjunction with the operation of the brake pedal 34, it takes about 0.1 to 0.2 seconds until the discharge amount of the pump 41 reaches a required specified value after the brake pedal 34 is depressed. take time. For this reason, in the first embodiment, at the initial stage of braking, the discharge amount of the pump 41 is insufficient, and the pressure in the supply chamber 32 is not maintained at 0 but is temporarily increased. At this time, the pressure P of the supply chamber 32_bIs the effective pressure-receiving area S of the large-diameter portion 28_bActing on the piston 30, the reaction force P on the piston 30_b× S_bTherefore, the amount of movement of the piston 30 is insufficient, and the pressurization of the pressurizing chamber 31 and the pressure adding chamber 33 is delayed, and the reaction force of the brake pedal 34 is increased to deteriorate the feeling of brake operation.
[0042]
In the hydraulic brake device 76 of the present embodiment, at this time, the free piston 79 of the accumulator 77 moves backward, and the brake fluid in the supply chamber 32 flows into the oil chamber 78A, so that the increase in pressure is alleviated. Since the oil chamber 78B on the back side of the free piston 79 communicates with the reservoir R, the pressure in the supply chamber 32 is maintained at substantially the same pressure as that of the reservoir R to reduce the increase in the reaction force of the piston 30. Can improve the feeling of brake operation.
[0043]
Thereafter, when the discharge amount of the pump 41 reaches a required specified value, the brake fluid in the supply chamber 32 is transferred to the supply chamber 31 and the pressure adding chamber 33 by the pump 41, and the free piston 79 of the accumulator 77 is returned to the original position. Pressure balance state of boost control, that is, the following formula
P_a= (F−F_k) / (S_a−S_c)
Is established. In this way, it is possible to improve the feeling of brake operation by reducing an increase in the reaction force to the brake pedal 34 in the initial stage of braking. Further, since the accumulator 77 is built in the piston 37, the master cylinder 26 can be reduced in size.
[0044]
On the other hand, when the automatic brake is activated, even if the supply chamber 32 is depressurized by the activation of the pump 41, the free piston 79 does not move in contact with the end of the cylinder bore 78, and the accumulator 77 does not operate. Automatic brake control can be executed as in the example.
[0045]
Next, a seventh embodiment of the present invention will be described with reference to FIG. The hydraulic brake device according to the seventh embodiment is generally similar to the sixth embodiment except that the structure of the accumulator built in the piston is different. The same parts as those in the sixth embodiment shown in FIG. 6 are denoted by the same reference numerals, and only different parts will be described in detail.
[0046]
As shown in FIG. 7, the accumulator 84 (pressure accumulating means) built in the piston 30 of the hydraulic brake device according to the seventh embodiment has a free piston 86 sliding in a cylinder bore 85 formed through the large diameter portion 28. The cylinder bore 85 is divided into two chambers of oil chambers 85A and 85B by a free piston 86. The oil chamber 85A is communicated with the supply chamber 32 via an oil passage 87, and the oil chamber 85B is communicated with the pressure addition chamber 33 via an oil passage 88. The free piston 86 is normally in contact with the end of the cylinder bore 85 on the oil chamber 85A side by the spring force of a return spring 89 provided in the oil chamber 85B.
[0047]
With this configuration, when the supply chamber 32 is pressurized and becomes higher pressure than the pressurization chamber 31 and the pressure addition chamber 33 in the initial stage of braking, the free piston 86 of the accumulator 84 moves backward, As the brake fluid flows into the oil chamber 85A, the pressure rise is alleviated. Since the oil chamber 85B on the back side of the free piston 86 is in communication with the pressure addition chamber 33 (the same pressure as the pressurization chamber 33), the pressure in the supply chamber 32 is almost the same as that of the pressurization chamber 31 and the pressure addition chamber 33. By maintaining the same pressure, it is possible to reduce an increase in the reaction force to the piston 30, and it is possible to improve the brake operation feeling as in the sixth embodiment. Thereafter, when the discharge amount of the pump reaches a necessary specified value, the supply chamber 32 is decompressed and the boost control can be executed under a predetermined pressure balance, as in the sixth embodiment.
[0048]
In this case, the pressure in the supply chamber 32 is substantially the same as that in the pressurizing chamber 31 and the pressure adding chamber 33, and is higher than that in the sixth embodiment in which the pressure is the same as that in the reservoir R. The effect of reducing the brake reaction force is slightly smaller than that of the form.
[0049]
When the automatic brake is activated, even if the supply chamber 32 is depressurized by the activation of the pump 41, the free piston 86 does not move in contact with the end of the cylinder bore 85, and the accumulator 84 does not operate. Similarly, automatic brake control can be executed.
[0050]
In the sixth and seventh embodiments described above, the accumulator is incorporated in the piston. However, in addition to this, an accumulator is arranged outside the mass cylinder to provide the supply chamber, the reservoir, and the pressure adding chamber. It can also be configured to connect.
[0051]
Next, an eighth embodiment of the present invention will be described with reference to FIG. In the eighth embodiment, since the function of the accumulator of the seventh embodiment is incorporated in the large-diameter portion of the piston of the first embodiment, the eighth embodiment is the same as that of the first and seventh embodiments. The same reference numerals are given to the same parts, and only different parts will be described in detail.
[0052]
In the hydraulic brake device 90 of the eighth embodiment, the large-diameter portion 91 (piston portion) of the piston 30 that defines the supply chamber 32 and the pressure adding chamber 33 is an annular shape in which the small-diameter portion 27 is slidably inserted. It consists of a member and is supported so as to be movable along the axial direction with respect to the small diameter portion 27 and the rod portion 29. A stopper 92 that contacts the large diameter portion 91 is attached to the small diameter portion 27 of the piston 30, and the large diameter portion 28 is a disc spring provided between the large diameter portion 28 and the shoulder portion of the rod portion 29. The spring force of 93 normally contacts the stopper 92.
[0053]
With this configuration, when the supply chamber 30 is pressurized in the initial stage of braking, the large-diameter portion 91 acts as an accumulator by retreating against the spring force of the disc spring 93, thereby supplying the supply chamber. Mitigates the pressure increase of 30. Thereby, the same operations and effects as those of the seventh embodiment can be achieved.
[0054]
Next, a ninth embodiment of the present invention will be described with reference to FIG. As shown in FIG. 9, the hydraulic brake device 94 of the ninth embodiment is similar to the accumulator of the eighth embodiment in the large diameter portion of the piston in the tandem hydraulic brake device of the second embodiment. It incorporates the function as. In FIG. 9, the same parts as those in the second and eighth embodiments are denoted by the same reference numerals. In the eighth embodiment, a disc spring 93 is used as a spring for urging the large-diameter portion 91, whereas in the present embodiment, a coil spring 95 is used.
[0055]
With this configuration, in the tandem hydraulic brake device of the second embodiment, the same operations and effects as those of the eighth embodiment can be achieved.
[0056]
【The invention's effect】
  As detailed above,The present inventionAccording to this hydraulic brake device, it is possible to perform boost control by pressurizing the pressurizing chamber and the pressure adding chamber connected to the wheel cylinder by a pump according to the operating force on the piston. The boost ratio can be determined by the difference between the effective pressure receiving area for the pressure chamber and the effective pressure receiving area for the pressure adding chamber.
  Also,By closing the on-off valve, the pressure in the pressure adding chamber can be made higher than the pressure in the pressurizing chamber by pressurizing the pump, and thus the piston can be advanced to operate the automatic brake..
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a hydraulic brake device according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing a hydraulic brake device according to a second embodiment of the present invention.
FIG. 3 is a circuit diagram showing a hydraulic brake device according to a third embodiment of the present invention.
FIG. 4 is a circuit diagram showing a hydraulic brake device according to a fourth embodiment of the present invention.
FIG. 5 is a circuit diagram showing a hydraulic brake device according to a fifth embodiment of the present invention.
FIG. 6 is a circuit diagram showing a hydraulic brake device according to a sixth embodiment of the present invention.
FIG. 7 is a longitudinal sectional view showing a schematic configuration of a piston of a hydraulic brake device according to a seventh embodiment of the present invention.
FIG. 8 is a circuit diagram showing a hydraulic brake device according to an eighth embodiment of the present invention.
FIG. 9 is a circuit diagram showing a hydraulic brake device according to a ninth embodiment of the present invention.
FIG. 10 is a circuit diagram showing a conventional hydraulic brake device having an automatic brake function.
FIG. 11 is a circuit diagram showing a conventional hydraulic brake device having a boost control function.
[Explanation of symbols]
25,45,53,60,72,76,90,94 Hydraulic brake device
26 Master cylinder
30 pistons
31 Pressurization chamber
32 Supply room
33 Pressure chamber
38,52 Wheel cylinder
41 pump
42 Pressure control valve
40 Proportional solenoid valve (open / close valve)
77,84 Accumulator (accumulation means)
91 Large diameter part (piston part)
R reservoir

Claims (3)

A stepped piston having a small-diameter portion and a large-diameter portion, a pressurizing chamber that is pressurized by the small-diameter portion by the advancement of the piston and connected to a wheel cylinder through a first pipe line, and the large-sized piston by the advancement of the piston A master cylinder having a supply chamber pressurized by a diameter portion, and a pressure addition chamber formed on the piston retreat side of the large diameter portion and connected to the wheel cylinder via a second pipe line;
An on-off valve provided in the second pipeline;
A pump having a suction side connected to the supply chamber and a discharge side connected between the pressure adding chamber of the second pipe line and the on-off valve;
Provided between the suction side of the pump and a third pipe connected to the first pipe, and communicates the suction side of the pump and the third pipe based on the pressure in the supply chamber A pressure control valve for shutting off,
An effective pressure receiving area of the piston with respect to the pressurizing chamber is larger than an effective pressure receiving area with respect to the pressure adding chamber;
The pressure control valve closes the third conduit when the pressure in the supply chamber is positive, and connects the third conduit to the suction side of the pump when the pressure in the supply chamber is negative. Communicate with
The hydraulic brake device according to claim 1, wherein the pump reduces the pressure of the supply chamber, which becomes positive pressure as the piston moves forward, to approach 0 by suction. 2. The hydraulic brake device according to claim 1, wherein the on-off valve is a proportional electromagnetic valve, and is opened when the brake pedal is operated and controlled to a half-closed state when the automatic brake is operated. The hydraulic brake device according to claim 1, further comprising a pressure accumulating unit connected to the supply chamber.

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