JPH0235022Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a braking fluid pressure control device for a vehicle, and more specifically, the invention relates to a braking fluid pressure control device for a vehicle. Regarding a control device.

(Prior Art) A conventional device of this type is shown in FIG. This is a hydraulic booster type brake oil pressure increasing device (hereinafter referred to as servo unit U).
This is due to the master cylinder Mc equipped with.
According to this, the operation of an input rod 2 connected to a brake pedal 1 is transmitted to a spool valve 4 via an operation rod 3. For example, by moving the spool valve 4 to the left in the figure, the first hydraulic port _P1 communicating with the reservoir tank 5 is closed, and the second hydraulic port _P2 communicating with the accumulator 6 is connected to the input rod 2. Adjust the opening accordingly. In this way, hydraulic pressure is introduced into the boost chamber P ₃ (hereinafter referred to as the first back pressure port) so as to act as back pressure to advance the power piston 7. By introducing back pressure into the first back pressure port _P3 , the power piston 7 is pressed and moved to the left in the figure, and this movement is transmitted to the master cylinder Mc side via the output rod 8. Rf and Rr are the front wheel and rear wheel cylinders to which the braking oil pressure from the master cylinder Mc is transmitted, 9 is the housing of the servo unit U, and 10 is the housing 9 that closes one end of the housing 9 to fluidize the operation rod 3. The front cap, 11, supports the housing 9 in a tightly slidable manner.
a rear cap 1 which closes the other end of the rear cap and slidably supports the output rod 8 in a fluid-tight manner;
Seal members 2 and 13, such as O-rings, are installed on the front cap 10 and the rear cap 11, respectively, to make the inside of the housing 9 liquid-tight.
Reference numeral 14 denotes an elastic dust boot covering the connecting portion between the input rod 2 and the operation rod 3. Further, 15 is a return spring that returns the power piston 7 to a normal position within the housing 9. In addition to the accumulator 6 and the reservoir tank 5, the members constituting the circuit of the hydraulic pressure supply source include an oil pump 16, a pump drive motor 17, and the like.

(Problems to be solved by the invention) However, in such conventional devices,
Since the depression input to the brake pedal 1 is transmitted as a braking output to each wheel cylinder Rf, Rr of the front and rear wheels at a constant ratio via the servo unit U and the master cylinder Mc, the depression force to the brake pedal 1 is calculated based on the weight of the vehicle. There was a problem in that it had to be artificially adjusted depending on when the weight was light or heavy.

Therefore, the present invention was made to solve the problems of the conventional devices described above, and is a brake fluid pressure control device that can obtain a braking output corresponding to changes in vehicle weight with a constant depression input to the brake pedal. intended to provide.

(Means for Solving the Problems) In order to solve the problems of such conventional devices and achieve the purpose, the brake fluid pressure control device according to the present invention, when a depression input is applied to the brake pedal, Corresponding to the opening/closing degree of the hydraulic port that changes as the operating piston moves in the input direction on the valve axis line, hydraulic pressure is introduced from the hydraulic source into the first back pressure port provided on the power piston, and the power is increased. A servo unit section that moves the piston in the input direction, a master cylinder section to which the operation of the power piston is transmitted and supplies braking hydraulic pressure to each wheel cylinder of the front and rear wheels, and a master cylinder section that is installed between the sprung mass and the unsprung mass. A load detection means for detecting vehicle weight; a control unit for controlling a detection signal from the load detection means; and a control unit that is actuated by a control signal from the control unit to apply hydraulic pressure from the hydraulic pressure source to the operating piston. and a hydraulic control valve section that acts as a back pressure to assist movement in the input direction.

Further, the brake hydraulic pressure control device according to the present invention has a second back pressure port so that the operating piston is assisted in movement in the input direction by the hydraulic pressure acting as the back pressure.

Further, in the brake hydraulic pressure control device according to the present invention, the hydraulic pressure control valve section is arranged in the housing so that the hydraulic pressure control valve section can communicate with each of the housing, the hydraulic pressure source, the first back pressure port, and the second back pressure port. a sliding chamber provided therein; and a hydraulic pressure source and a second backpressure port that are slidably fitted into the sliding chamber and receive backpressure from the first backpressure port. an auxiliary spool valve that moves in a direction to communicate with the auxiliary spool valve; an auxiliary spring that presses the auxiliary spool valve in a direction that disconnects the hydraulic pressure source from the second back pressure port; A valve driving means is provided for moving the output shaft and setting the spring load of the assisting spring.

(Embodiment) Hereinafter, an embodiment of the brake hydraulic pressure control device according to the present invention will be described with reference to the drawings. Note that the same reference numerals used in the description of the conventional example refer to the same kind or the same members.

As is clear from FIG. 1, the embodiment has a structure in which the servo unit U and master cylinder Mc described in the conventional example are integrated. That is, the configuration on the master cylinder part Mc' side is shown as belonging to a tandem type. The outline is as follows: 20 is the primary piston, 21 is the secondary piston, 22 and 23 are both return springs, 1 is the first pressure chamber that communicates with the front wheel cylinder Rf, and 2 is the second pressure chamber that communicates with the rear wheel cylinder Rr. , and 24 is a reservoir tank communicating with the first and second pressure chambers. The primary piston 20 has an engaging portion 20a that is large enough to encompass and engage with the output rod 8 on the servo unit U' side. The engaging portion 20a is slidably guided by a guide member 25 that is integrally fitted to the housing 18,
The primary piston 20 is configured to be able to move from its normal position in the figure to the left in the figure on the valve axis by the pressure of the output rod 8. Further, an oil passage hole 25a passes through the guide member 25 in the valve axis direction, and the oil supply port 24a of the reservoir tank 24 and the tank hydraulic chamber A in the housing 18 communicate with each other through the oil passage hole 25a. ing.

Next, a description will be given of the structure of the hydraulic pressure control valve part 30, which is provided to protrude from the housing 18 in a direction perpendicular to the valve axis of the servo unit part U'. 31 is a housing protrusion that is integrally provided with the housing 18, and 32 is a stepping motor (valve drive means) coupled to the housing protrusion 31, and this output shaft 32a is the valve shaft in the vertical direction in the figure. Go back and forth on the line. 3
3 is a support spool valve which is also slidable on the valve axis, and 34 is an output shaft 32a and a support spool valve 3.
3, and connects both members to each other via their flange joints 35, 36. 37 is the above-mentioned assisting spool valve 33
This is a flexible boot that liquid-tightly closes the sliding chamber portion 31a on which the auxiliary spool valve 33 slides, and expands and contracts in conjunction with the sliding movement of the assisting spool valve 33. Here, the shape of the assisting spool valve 33 is stepped so that the center part becomes tapered, and a hydraulic oil chamber B is formed between the pressure receiving stepped part 33a and the sliding chamber part 31a. It is becoming more and more common. Further, the housing projecting portion 31 in the portion corresponding to the sliding chamber portion 31a is further provided with an oil passage hole 38 that communicates with the hydraulic port _P2 on the servo unit U' side via an oil passage 43, and a first back Pressure port P ₃
An oil passage hole 39 communicating with the reservoir tank 42 and an oil passage hole 40 communicating with the reservoir tank 42 are provided. Further, a second back pressure port P4 is defined between the pressure receiving step portion 3a formed at the rear of the operating piston 3 and _the front cap 10, and this second back pressure port _P4 and the It communicates with the hydraulic oil chamber B through an oil passage hole 41. The oil passage hole 41 passes through both the front cap 10 side and the housing protrusion 31.

On the other hand, a load sensor (load detection means) 50 is installed between the sprung portion and the unsprung portion of the vehicle body, and a control unit 60 controls a detection signal of the vehicle weight detected by the load sensor 50. The control signal from the control unit 60 is transmitted to the hydraulic control valve section 3.
The output shaft 32a is sent to the stepping motor 32 on the 0 side so that the output shaft 32a moves in either the vertical direction in the figure on the valve axis.

Next, the operation of the apparatus of the embodiment having the above-described configuration will be explained.

When the load sensor 50 detects the weight of the vehicle due to the occupants and the loaded load, this detection signal is controlled by the control unit 60, and an operation command based on this control signal is sent to the stepping motor 32. When the actuation signal is input, the output shaft 32a moves on the valve axis line, and the pressing spring load of the assisting spring 34 against the assisting spool valve 33 is set.

That is, when the weight of the vehicle is large, the pressing load on the assisting spool valve 33 is set by the load sensor 50 detecting the weight of the vehicle at this time, and a control signal from the control unit 60 based on this detection signal. Output shaft 32 of ping motor 32
The determination is made in a state in which a moves a predetermined distance downward in the figure, reducing the pressing force on the assisting spring 34 and reducing the pushing force on the assisting spool valve 33.

On the other hand, when the vehicle weight is small, the setting of the pressing load on the assisting spool valve 33 is performed by the control unit 6 based on the detection signal of the vehicle weight at this time.
In response to the control signal from 0, the output shaft 32a of the stepping motor 32 moves upward in the figure by a predetermined distance, increasing the pushing force on the assisting spring 34 and increasing the pushing force on the assisting spool valve 33. It is decided based on the condition.

Therefore, for example, when braking when the vehicle weight is large, when a depression input is applied to the brake pedal 1, the hydraulic pressure corresponding to the opening degree of the hydraulic ports P ₁ and P ₂ on the servo unit U' side is increased. is introduced into the first back pressure port _P3 , and the power piston 7 moves to the left in the figure by the hydraulic pressure of the first back pressure port _P3 . At this time, the hydraulic pressure at the first back pressure port _P3 simultaneously acts as pilot pressure on the tip of the assisting spool valve 33 on the side of the hydraulic pressure control valve section 30, and acts to push it downward in the figure. When the force generated by the pilot pressure and the spool valve cross-sectional area becomes larger than the previously set pressing spring load, the assisting spool valve 33 moves downward in the figure on the valve axis. By this movement of the assisting spool valve 33, the hydraulic pressure from the accumulator 6 in the hydraulic oil chamber B is transferred to the second back pressure port _P4 through the oil passage hole 41.
This oil pressure acts as a back pressure on the rear pressure receiving step portion 3a of the operating piston 3, pushing the operating piston 3 to the left in the figure. That is, in addition to the depression input from the brake pedal 1, the hydraulic pressure at the second back pressure port _P4 acts on the operating piston 3.
As a result, a large pressure input corresponding to the large vehicle weight acts on the operating piston 3, and this large pressure input is applied to the power piston 7, output rod 8, and master cylinder section.
Both primary and secondary pistons 2 on Mc′ side
0 and 21, and the braking oil pressure thus controlled acts as a braking force on the front wheel cylinder Rf and the rear wheel cylinder Rr from the output ports _P5 and _P6, respectively.

On the other hand, during braking when the vehicle weight is small, the pressing load on the assisting spring 34 is initially set to be large, so the first back pressure port P ₃
Hydraulic pressure acting on the assisting spool valve 33 via the oil passage 39 is applied to the initially set assisting spring 34.
It is not enough to overcome the pressing load and push down. Therefore, the hydraulic pressure in the hydraulic oil chamber B at this time is either not introduced into the second back pressure port _P4 via the oil passage 41 at all (if the assisting spool valve 33 does not operate at all), or even a small amount is introduced. (When the assisting spool valve 33 operates even slightly)
Thus, only a pressing force corresponding to the depression input from the brake pedal 1 mainly acts on the operating piston 3, with even a small amount of back pressure or no back pressure acting on the operating piston 3.

(Effects of the invention) As can be understood from the above, the brake hydraulic pressure control device according to the invention increases or decreases the hydraulic pressure from the hydraulic source by controlling the hydraulic pressure control valve section in response to changes in vehicle weight. This controlled hydraulic pressure is used as back pressure and is added to the depression input from the brake pedal, which is then supplied to each wheel cylinder on the front and rear wheels as braking hydraulic pressure, so a constant depression input to the brake pedal is enough to control the vehicle. Braking output corresponding to changes in weight can be applied to the front and rear wheels. Moreover, since the boost pressure generated by the pedal input is input and is applied directly to the hydraulic control valve for generating the back pressure, the pedal input and the back pressure assisting force are synchronized, which increases the pressure on the front and rear wheels. The operation of applying braking force is performed appropriately.

[Brief explanation of the drawing]

FIG. 1 is an overall sectional view showing an embodiment of a brake hydraulic pressure control device according to the present invention, and FIG. 2 is an overall sectional view of a conventional device. 1...Brake pedal, 3...Operation rod, 3a...Pressure receiving stage, 4...Spool valve,
6... Accumulator, 7... Power piston, 8... Output rod, 16... Hydraulic pump, 18... Housing, 20... Primary piston, 21... Secondary piston, 24...
...Reservoir tank, 25...Guide member, 30...
...Liquid pressure control valve part, 31...Sliding chamber part, 32...Stepping motor (valve drive means), 32a...Output shaft, 33...Assisting spool valve, 38, 39, 4
1...Oil hole, 50...Load sensor (load detection means), 60...Control unit, _P1 , _P2 ...Hydraulic port, _P3 ...First back pressure port, _P4 ...Second Back pressure port, B...Hydraulic oil chamber, Rf...Front wheel cylinder for the front wheel, Rr...Rear wheel cylinder for the rear wheel.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) When a depression input is applied to the brake pedal, the operating piston moves in the input direction on the valve axis, which corresponds to the opening/closing degree of the hydraulic port that changes. , a servo unit section that introduces hydraulic pressure from a hydraulic source into a first back pressure port provided on the power piston to move the power piston in the input direction; and a servo unit section that moves the power piston in the input direction; a master cylinder section that supplies braking hydraulic pressure to the wheel cylinder; a load detection means installed between the sprung mass and the unsprung mass for detecting vehicle weight; and a control unit that controls a detection signal from the load detection means; a hydraulic control valve section that is actuated by a control signal from a control unit and causes hydraulic pressure from the hydraulic source to act on the operating piston as back pressure to assist movement in the input direction. A brake fluid pressure control device characterized by: (2) The utility model registration claim 1 is characterized in that the operating piston has a second back pressure port so that movement in the input direction is assisted by the hydraulic pressure acting as the back pressure. 1
Brake hydraulic pressure control device as described in . (3) A sliding chamber portion provided inside the housing so that the hydraulic pressure control valve portion can communicate with the housing, the hydraulic power source, the first back pressure port, and the second back pressure port, respectively. and an assisting force that is slidably fitted inside the sliding chamber and moves in a direction to communicate the hydraulic pressure source and the second back pressure port in response to back pressure from the first back pressure port. a spool valve, an auxiliary spring that presses the auxiliary spool valve in a direction to shut off the hydraulic pressure source and the second back pressure port, and an output shaft that is moved by a control signal from the control unit to 2. The brake hydraulic pressure control device according to claim 1, further comprising a valve driving means for setting the spring load of the assisting spring.