JPS5959555A - Speed reduction sensitive braking liquid controller for car - Google Patents

Abstract

PURPOSE:To achieve optimal liquid pressure irrespectively of the stepping speed by placng a variable orifice to be enlarged in accordance to the flow speed of braking liquid at predetermined position in liquid pressure path thereby decreasing the restriction effect as the stepping speed of brake pedal increases. CONSTITUTION:It is comprised of P valve 34 having a differential piston 36 and a valve seat 38 to be arranged at the left of a stepped inner hole 12 of a housing 10, a control piston 50 arranged in a partition wall member 40 provided in the central portion of the inner hole 12 and a speed reduction sensitive valve 42 having an inertia ball 44 and a valve seat 46 to be arranged at the right of the inner hole 12. Here a variable orifice 84 is placed in a path 82 conducting between a liquid chamber 70 for containing the inertia ball 44 of said valve 42 and a liquid chamber 72 formed in said member 40 with said piston 50. Said variable orifice 84 is constructed of a tubular rubber resilient member and enlarged in accordance to the flow speed of braking liquid flowing from the liquid chamber 70 toward liquid chamber 72.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deceleration-sensitive braking fluid pressure control device for a vehicle that controls rear wheel brake fluid pressure of a vehicle, and more particularly, to a fluid pressure control valve, i.e. The present invention relates to a deceleration sensitive brake fluid pressure control a11 device whose operation is controlled by a control piston whose operation is controlled by a valve.

This type of device generally has a housing that has an inflow boat connected to a brake mask cylinder and an outflow boat connected to a rear wheel cylinder, and has a crotch inner hole therein that communicates with both ports. and a hydraulic pressure control valve that controls hydraulic pressure applied to the rear wheel cylinder through the outflow boat in cooperation with a spring-biased differential piston provided in the stepped bore of the housing. , a liquid that is slidably provided in the axial direction in an inner hole that is coaxial with the inner hole of the stage I, and that has one end aligned with the other end of the differential piston and acts on the other end. A control screw 1 which is bent and pressed against the differential piston by pressure communicates with a part of the inner hole where the other end of the control piston is exposed and the inflow boat. A deceleration sensitive hartz is provided in the communication passage and adjusts the hydraulic pressure applied to the inner hole when a predetermined deceleration is detected.

By the way, in this type of device, as is generally known, due to a delay in the activation timing of the deceleration sensitive Halval described in AiJ, the pressing speed of the brake pedal &i'7 inclusive speed and master cylinder hydraulic pressure Accordingly, the i1ν pressure applied to the control screw I and t'1jAl increases as shown in a in FIG. (point b shown in 1131) A considerably higher hydraulic pressure of 1 rU may be applied to the other end of the control piston. In the case of overcasting, the so-called 1
] The hydraulic pressure at each point of the valve increases, and there is a risk that the rear wheels will not lock up early.

In order to cope with this problem, Japanese Patent Laid-Open No. 114565/1984 discloses a means for providing a fixed throttle at the introduction end of the communication passage. According to this means, since the transmission of hydraulic pressure to the control piston can be delayed by the fixed throttle, the hydraulic pressure applied to the other end of the control piston can be delayed compared to the case where no fixed throttle is provided. Although the rise can be suppressed,
There are the following problems. In other words, if the orifice diameter of the fixed throttle is small, the throttle effect will be optimally obtained when the brake pedal is depressed a little early, as shown by C in Figure 1, and the above-mentioned hydraulic pressure will approximate the desired hydraulic pressure. However, when the pedal is depressed rapidly, the effect of the throttle becomes large and the hydraulic pressure becomes too low. This is caused by insufficient braking force, especially when the vehicle is heavily loaded (when the vehicle is loaded with approximately half of the maximum load capacity) or when the vehicle is loaded with a constant load (when the vehicle is loaded with the maximum load capacity). This causes the front wheels to lock up early.

On the contrary, if the orifice diameter of the fixed throttle is large, as shown in d in Figure 1, the throttle effect is optimally obtained during rapid depressing, and the above hydraulic pressure approximates the desired hydraulic pressure. However, when the pedal is pressed down rather quickly, the throttle effect is not sufficiently obtained and the above-mentioned hydraulic pressure increases, resulting in the problem of early locking of the rear wheels, especially when the pedal is empty.

The present invention has been made to solve this problem, and its purpose is to maintain a hydraulic pressure close to the desired hydraulic pressure at the other end of the control piston (=j
The object of the present invention is to provide a device that can obtain stable performance according to the given conditions. In order to achieve this purpose, in the present invention, a variable orifice is interposed in the communication passage, which is expanded according to the flow velocity of the brake fluid flowing toward a part of the inner hole. . As a result, in the present invention, the effect of the throttle is gradually reduced as the brake pedal depression speed increases, and regardless of the brake pedal depression speed,
You can get the most suitable aperture effect.

Therefore, as shown at e in FIG. 1, regardless of the brake pedal depression speed, a hydraulic pressure close to the desired hydraulic pressure is applied to the other end of the control piston, resulting in stable performance. .

An embodiment of the present invention will be described below based on the drawings.

In the deceleration-sensitive brake hydraulic pressure control device shown in FIG.
4 and a plaque 6 screwed together and fixed within a portion between the right end of the body 14. The plug 16 has
An inflow boat 18 is provided, and this inflow boat 8 is connected to one pressure chamber of the tandem brake mask cylinder 22 by a vibrator 2o. On the other hand, an outflow boat 24 shown by a broken line is provided at the left end of the body 14, and this outflow boat 24 is connected to a rear wheel cylinder 28 by a vibrator 26. Further, the front wheel cylinder 3o is connected to the other pressure chamber of the tandem brake mask cylinder 22 by a vibrator 32.

Inside the left side of the stepped inner hole 12 of the housing 10 is a P
A differential piston 36 and a valve seat 38 constituting the valve 34 are disposed, a partition port 4o is disposed in the center of the stepped inner hole 12, and a partition opening 4o is provided in the right side of the stepped inner hole 12. Inertia ball 44 forming speed sensitive valve 42
A hull seat 46 and a ball case 48 are provided, and a control screw 1-50 is provided within the partition wall 11X+A40.

The bulkhead member 40 has a main body 52 and a portion 4 fitted within the main body 52 having an internal bore 54 coaxial with the stepped internal bore 12 that slidably supports the control piston 50 in the axial direction. ;and,
Inner hole 1 into which the right end of the differential piston 36 is inserted
2 and a hole 58 coaxial with the main body 52, the member 60 is screwed and fixed in the left opening of the main body 52, and an air chamber 66 for accommodating a compression coil spring 62 and a retainer 64 is formed inside. has been done. This partition wall f'fB+,
The partition wall member 40 is supported by the stepped portion of the body 14 and the left end of the plaque 16 and is fixed within the housing song 10.
2 is divided into a first liquid chamber 68 on the left that accommodates the valve 34 and a 27th chamber 70 on the right that accommodates the deceleration sensitive valve 42 and communicates with the first liquid chamber (i8). are doing.

The differential piston 36 is supported slidably in the axial direction by the partition wall:'1lI4A4o and the body 14 at two places, the right end and the left end, and the right 1γ11.1 part is supported by the air chamber G6.
It plunges into the inside and abuts against the retainer 64. The valve seat 38 is an annular member made of soft rubber paulownia material, and the differential piston 36 passes through it with a gap. The leftward movement of the valve seat 38 is defined by the stepped portion of the body 14, and the rightward movement thereof is defined by the differential piston 36.

The valve seat 38 has a large number of small protrusions on the part facing the stepped part of the body 14 and the part facing the differential piston 36 (in the left direction) to ensure a gap as a liquid passage. . The coil spring 62 is tensioned between the control piston 50 and the retainer 64 with a predetermined preload applied thereto. 64 and the differential piston 36 to the left.The leftward movement of the differential piston 36 is caused by the movement between its left end and the stage (=J inner hole 12
is regulated by contact with the left end wall. Further, the effective seat diameter of the valve seat 38 is larger than the diameter of the right end portion of the differential piston 36.

The ball 44 of the deceleration sensitive valve 42 is located in a ball case 48
Make a ball with a diameter slightly smaller than the inner diameter of the ball.
They can be transferred to the left or right within the space 48. The valve seat 46 is attached to a cylindrical groove (1
It is fixed to the outer periphery of part 4I! l1lJ fall
A liquid chamber 72 formed in the piston 50 in the piston 50 communicates with the second liquid chamber 70 through the center hole of the valve seat 46 . The left end of the ball case 48 is connected to the right side of the bulkhead portion 40 by a spring 74.
It is substantially fixed to the bulkhead portion 40 each time it is pushed up to 1 and the left end protrusion is inserted into the hole in the bulkhead portion 40. A through hole 76 is provided in the right end wall of the ball case 48, and a notch 78 is provided in the thick peripheral wall portion (upper left in the figure). Furthermore, a protrusion 8o is provided on the outer periphery of the right side 1 of the ball case 48 for setting the excitation of brake fluid passing through the through hole 76.

The control screw i/n 5o is pushed to the left against the spring 62 in the air chamber 66 by the liquid pressure in the liquid chamber 72, and its right end protrudes into the liquid chamber 72. It is exposed. The diameter of the right end of the control piston 50 (the diameter that receives hydraulic pressure) is smaller than the diameter of the right end of the operating piston 36 (the diameter that receives hydraulic pressure). Note that the rightward sliding movement of the control piston 5o is restricted by the contact between the flange 51 and the portion 4A'56.

In this embodiment, as shown in FIGS. 2 and 3, a variable orifice 84 is interposed in a communication passage 82 that communicates the second liquid chamber 7o with the liquid chamber 72. The variable orifice 84 is made of a cylindrical rubber elastic body, and has a through hole 85 at the axis fitted to the stepped portion of the communication passage 82.
The retainer 86 is fitted into the right end portion of the retainer 86. This variable orifice 84 narrows toward the left end,
The opening is expanded as shown in FIG. 4 in accordance with the flow velocity of the brake fluid flowing from the second fluid chamber 70 toward the fluid chamber 72.

The device configured as described above is used by being attached to a vehicle body such as a truck with a predetermined inclination θ, and when braking,
As shown in FIG. 5, the hydraulic pressure applied to the rear wheel cylinders 28 is controlled according to the loading state of the vehicle. The action will be explained in detail below.

When the driver 1 depresses the brake pedal to stop the vehicle, the master cylinder 22 is activated, and hydraulic pressure is transferred from the other pressure chamber of the tandem brake mask link to the front wheel cylinder 30 via the pipe 32. The hydraulic pressure is supplied from one pressure chamber of the tandem brake mask link to the pipe 20. Brake hydraulic pressure control device,
The brakes are applied to the rear wheel cylinder 28 via the pipe 26, and the front and rear brakes start operating, thereby starting a braking action.

Note that the hydraulic pressure transmission within the brake hydraulic pressure control device is based on the inflow bow 1.
-18. Second liquid chamber 70. First liquid chamber 68. open I)
Valve 34. This is done in the order of inflow port 24.

When the vehicle deceleration caused by the above-mentioned braking action reaches a predetermined value, the ball 44 moves to the left in FIG. The hydraulic pressure transmission is cut off.The hydraulic pressure within the wheel cylinder that reaches the wheel brake when a predetermined value of vehicle deceleration occurs varies depending on the top position of the vehicle, and gradually increases as the load increases. Therefore, the effects at each loading time will be explained below.

When the load is empty, the spring force of the spring 62 is
The turning point liquid pressure 1 of the P valve 34 when the time remains the same
) The vehicle deceleration reaches a predetermined value with the hydraulic pressure approximately equal to 1, and the hole 44 seats on the valve seat 46. During this time, although hydraulic pressure is applied to the liquid chamber 72 through the valve seat 46, the control piston 50 does not slide against the spring 62 because the pressure is small. Therefore, the spring force of the spring 62 remains the same as when it was installed, and P
The valve 34 performs a conventionally known pressure reducing operation as the mask cylinder hydraulic pressure increases, and the hydraulic pressure applied to the rear wheel cylinder 28 reaches point 0 in FIG. Control is performed as shown by the line connecting A and B.

Further, when the vehicle is piled up, the vehicle deceleration reaches a predetermined value due to the hydraulic pressure P2 which is higher than the turning point hydraulic pressure Pl by a predetermined value, and the ball 44 is seated on the valve seat 46.

During this time, liquid pressure is applied to the liquid chamber 72 through the knob sheet 46, as in the case of empty storage described above. Shishika L-j,
At this time, the highest hydraulic pressure applied to the liquid chamber 72 (the hydraulic pressure when the ball 44 is seated on the valve seat 1-46) causes the control piston 50 to move against the spring 62 and
The spring force of the spring 62 is increased by a predetermined amount -1 compared to the time when the spring 62 is moved to the left in the figure by a predetermined 1i11.1ijl.
,4ru. Therefore, at this time, the hydraulic pressure applied to the rear wheel cylinder 28 is at the point 0°△ in FIG.
It is shown by the line connecting C, I) and IE.)G is controlled. Here, the line connecting points A and [Y is the control piston 50
This is a characteristic that is obtained each time the valve 34 performs a conventionally known pressure reducing operation when the control piston 50 resists the spring 62. When the ball 44 slides to the left and the p-valve 34 opens and closes, the line connecting point 1) and FE indicates that the ball 44 is in the valve seat 1-46, f Ink, and control piston 50
Each time the valve 34 stops, the spring force of the spring 62 is maintained at a value that is increased by a predetermined amount compared to when the valve 34 is installed.

In addition, at the time of constant volume, even if the mask cylinder hydraulic pressure exceeds P2, the vehicle deceleration does not reach the predetermined value, and the ball 44
Otherwise, it will not sit on the valve seat 46.

Therefore, the hydraulic pressure is continuously transmitted from the second liquid chamber 70 to the liquid chamber 72, and the control piston 50 slides against the spring 62, continuing to increase the spring force of the LJ spring 62. Therefore, at this time, the rear wheel cylinder 2
The hydraulic pressure applied at point 8 is at point 0 in Figure 5. A, C, D, l;
' is controlled as shown by the line connecting '. Iron, point 0.
The line connecting A, C, and D is the characteristic obtained by the same operation as in the case of intussusception, and the operation obtained in the line connecting 1 point and the line connecting 0.1 points is obtained continuously. This is a characteristic obtained by

In this embodiment, the second liquid chamber 70 and the liquid chamber 7
A variable orifice 84 is interposed in a communication passage 82 that communicates between be delayed. However, i′iJ strange orifice 84
The second fluid chamber 7 corresponds to the brake pedal depression speed.
Since the brake fluid is expanded according to the flow velocity of the brake fluid flowing from zero to the fluid chamber 72, the effect of increasing the depression speed of the brake pedal is gradually decreased, and the effect of increasing the brake pedal depression speed is gradually reduced. Regardless of the brake pedal depression speed, the optimum throttling effect is always achieved.Therefore, as shown in e in FIG. A liquid pressure approximating that of pressure is applied,
Stable performance can be obtained.

FIGS. 6 and 7 show modified examples of the variable orifice, and the variable orifice 184 shown here is
It is made of a rubber elastic body with a bend. The manoko variable orifice] 84 is fitted to the right end of a retainer 186 having a through hole 185 fitted to the stage 6B of the communication passage 82, and is attached to the inner periphery of the left &IAI'/NX flesh cylinder 11; A notch 184a and a recess 184b are formed in the second fluid chamber 7o and expand as shown in FIG. 8 according to the flow velocity of the brake fluid flowing from the second fluid chamber 7o toward the fluid chamber 72. , this variable orifice] 84 can also be used to obtain the same effect as in the above embodiment.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the relationship between the brake pedal depression rate, the pressure increase rate of the mask cylinder liquid pressure, and the liquid pressure applied to the control piston, and Fig. 2 is a graph showing the relationship between the brake pedal depression rate, the pressure increase rate of the mask cylinder liquid pressure, and the liquid pressure applied to the control piston, and Fig. 2 is a graph showing the relationship between the brake pedal depression rate, the pressure increase rate of the mask cylinder liquid pressure, and the liquid pressure applied to the control piston. A brake system diagram including a pressure control device; FIG. 3 is an enlarged sectional view of the main part of FIG. 2, that is, the variable orifice;
Fig. 4 is an enlarged view of the same main parts during operation, Fig. 5 is a graph showing the performance of the device shown in Fig. 2, Fig. 6 is an enlarged sectional view showing a modification of the variable orifice, 7 is a left side view of the same, and FIG. 8 is an enlarged sectional view of the variable orifice when it is in operation. Explanation of symbols 10...Housing, 12...Stepped inner hole, 18...
・Inflow boat, 22...Brake mask cylinder, 2
4...Outflow port, 28...1 Mugiwa wheel cylinder, 34...P valve (hydraulic pressure control valve), 36...
・Differential piston, 42...Deceleration sensitive valve, 5o・
...Control piston, 72...Liquid chamber (part of inner hole), 8
2...Communication path, 84.184...Variable orifice.

Claims (1)

[Claims] A housing having an inflow port connected to a brake mask cylinder and an outflow port connected to a rear wheel cylinder, and having a stepped inner hole communicating with both the boats therein; Hydraulic pressure that controls the hydraulic pressure applied to the rear wheel cylinder 4 through the outflow bow 1 in cooperation with a differential piston provided in the stepped inner hole of the housing. A control valve is provided so as to be slidable in the axial direction in an inner hole provided coaxially with the inner hole of the stage A, and faces the differential piston at its -θ11) and at the other end thereof. A spring-biased fill piston that is pushed toward the differential piston by the applied hydraulic pressure, and a connection that communicates the inlet boat with the part of the inner hole where the other end of the control piston is exposed. A deceleration-sensitive brake fluid pressure control device for a vehicle, comprising a deceleration-sensitive valve that is interposed in a passage and shuts off hydraulic pressure (=J) applied to the inner hole when a predetermined deceleration is detected. , deceleration-sensitive braking 111 for a vehicle, characterized in that a variable orifice that expands in accordance with the flow velocity of brake fluid flowing toward a part of the inner hole is disposed in the communication passage;
Pressure control device.