JP3532053B2 - Automatic control brake system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake system capable of automatically controlling a brake fluid pressure, not only by a human operation, but also by a traction control, for stable running and for preventing a rear-end collision.

[0002]

BACKGROUND OF THE INVENTION In a brake system of a vehicle or the like, two or more independent piping systems are applied to ensure safety. The tandem master cylinder is a hydraulic pressure generator used for the tandem master cylinder. Such a tandem master cylinder generally defines a cylinder body including a cylinder hole extending from one end on the opening side in the axial direction and a first hydraulic chamber and a second hydraulic chamber in the cylinder hole inside the cylinder body. A first piston and a second piston, and a brake operating unit that moves the pistons to generate a brake fluid pressure in each of the first and second fluid pressure chambers. A usual brake operating means is a pedal and a push rod which is interlocked with the pedal. When the driver depresses the pedal, the push rod moves the first piston to generate a hydraulic pressure in the first hydraulic chamber, and also the second piston is moved in response to the movement of the first piston. A hydraulic pressure is also generated in the two hydraulic chambers.

On the other hand, in order to ensure further safety in the brake system, the brake fluid pressure can be obtained without performing a manual brake operation by the brake operating means (that is, independently or independently of the manual brake operation). It is desired to perform automatic control that automatically causes When enabling two control modes of human brake control and automatic control in a brake system of two or more systems, a brake operating means operated by a driver is used in order to share a hydraulic pressure generator. The included tandem master cylinder will also be used as a hydraulic pressure generator for automatic control. In the tandem master cylinder, in the automatic control mode, since the brake operating means is in the non-operating position, it is necessary to supply the pressure liquid from the external pump device. In that case, if each system is equipped with a pump device, the configuration of the device and piping becomes complicated, and the cost of the system increases. Therefore, there is an idea to unify the pump device so that the human braking operation means is single.

The publication of Japanese Patent Application Laid-Open No. 7-172280 clarifies the idea of unifying such a pump device.
There, by introducing a discharge pressure liquid from an external pump device into the first hydraulic chamber, a hydraulic pressure is generated in the first hydraulic chamber, and the second piston is moved by the generated hydraulic pressure. The hydraulic pressure is also generated in the second hydraulic chamber. By the way, in the automatic control mode, unlike in the manual brake control, the first piston is in the inoperative position. The first piston that does not move cannot shut off the connection between the first hydraulic chamber and the reservoir. Therefore, in the technique of the above publication, an opening / closing valve made of a solenoid valve is provided in the middle of the passage that connects the first hydraulic chamber and the reservoir. The on-off valve is normally open, and is controlled to be closed by receiving a control signal from the electronic control circuit during automatic braking.

However, when a method of interposing such an electromagnetic opening / closing valve is applied as a means for shutting off the first hydraulic chamber from the reservoir side during automatic control, the electromagnetic valve itself is compared with a general mechanical valve. There is a disadvantage that it is large in size and needs to be electrically connected to an electronic control circuit.
Therefore, the applicant of the present invention, in the first passage communicating between the reservoir and the first hydraulic chamber in the cylinder body, responds to the increase in the hydraulic pressure in the first hydraulic chamber and changes the state from the open state to the closed state. We first proposed a technology with an on-off valve that switches to (Japanese Patent Application No. 8-13
0943). The on-off valve in the proposal is composed of only mechanical components, and for example, a plate-shaped valve body is elastically deformable by receiving hydraulic pressure, and the valve is opened and closed by utilizing the elastic deformation. Therefore, the valve does not include an electromagnetic coil and does not require a connection with the electronic control means.

[0006]

[Problems to be Solved] Now, in the previously proposed technique using a mechanical valve, and other background techniques using an electromagnetic on-off valve, in any of them, an on-off valve for automatic control is provided as a reservoir. Boss of the cylinder body to which
Alternatively, it is arranged in the middle of the pipe connected to the boss.
Therefore, when the tandem master cylinder is operated normally by human operation, a portion where hydraulic pressure does not reach, for example, to a ring-shaped space between the outer circumference of the first piston and the inner circumference of the cylinder body, It was found that the pump pressure was transmitted during automatic control. To respond to that,
It is necessary to change the seal member that holds the outer periphery of the first piston or the parts such as a stopper that holds the seal member to a member that has sufficient pressure resistance to withstand the pump pressure. This goes against the design concept of sharing more components between the master cylinders for the automatic control brake and the normal brakes. Further, during automatic control, since the pump pressure acts on the seal member on the outer periphery of the first piston, the pressure contact force of the seal member increases,
When the master cylinder is manually operated during the automatic control, the movement resistance of the first piston increases, and the pedal effort for the operation increases. The present invention has been made in view of the above background, and a new brake that enables a tandem master cylinder used only for human brake control to be used in its automatic control system with a slight modification. The purpose is to provide a system. In addition, the present invention, in order to obtain an automatic control mode,
Another object is to provide a technique in which the communication between the first hydraulic chamber side and the reservoir side is restricted by an orifice.

[0007]

In the present invention, attention is paid to the fact that the automatic control does not require a braking force as much as in the case of a normal human braking operation. It was noted that the chamber does not necessarily have to be completely contained, but the flow may be restricted, for example, by a restriction. As such a flow restricting means, use an orifice or a clearance passage, and an opening / closing valve mainly made of a rubber plate, which has a very simple structure and only needs a small space for installation. You can In the present invention, when the brake is operated by the automatic control, such a flow restricting means is used in order to increase the pressure in the first hydraulic pressure chamber on the primary side by the pump pressure. It is arranged near the chamber so that the portion where the pump pressure is propagated is limited to the portion near the first hydraulic chamber. The first passage that connects the first hydraulic chamber and the reservoir is a passage that extends from the first hydraulic chamber to the first shutoff valve, and further from the ring-shaped space between the piston and the cylinder body to the reservoir. Here, the flow restricting means is arranged from the first hydraulic chamber to the ring-shaped space, and more preferably from the first hydraulic chamber to the first shutoff valve. As the flow restricting means, for example, an orifice having a diameter of about 0.7 to 0.8 mm is suitable, and in order to prevent clogging of the orifice, a filter is installed in front of the orifice facing the first hydraulic chamber side. It is good to do so. The flow restriction function of the flow restriction means including the orifice is determined by the characteristics of the pump device that generates the pump pressure and the magnitude of the generated hydraulic pressure required during automatic control. Therefore, for example, by selecting the characteristics of the pump device, the orifice as the flow restricting means is replaced with the existing brake loosening hole (usually,
It can also be used in common with a diameter of about 0.5 mm). Further, the number of the orifices may be one or plural, and in the case of plural orifices, the orifices as a whole have a diameter of, for example, about 0.7 to 0.8 mm.

Further, according to the present invention, a center valve type located on the central axis of the piston or a seal member held on the cylinder body side opens and closes a brake loosening hole provided in the piston as the piston moves. In addition to the plunger type, the seal member is composed of a double ring consisting of an inner circumference rubber ring and an outer circumference plastic ring.In addition to the brake loosening hole provided in the cylinder body, the hydraulic chamber communicates with the reservoir side, It can also be applied to an improved version of the conventional type in which a liquid replenishment passage capable of replenishing the chamber is provided inside the piston. In the improved version of the plunger type or conventional type, the brake loosening hole itself can be used as an orifice for limiting the propagation of pump pressure. Further, in the improved version of the conventional type, the gap between the inner peripheral wall of the cylinder body near the brake loosening hole and the land on the outer periphery of the piston can be used as a throttle for limiting the propagation of pump pressure.

[0009]

[First Embodiment] FIG. 1 shows an overall piping system of a brake system 10 according to the present invention. In particular, a tandem master cylinder 20 as a hydraulic pressure generator is shown in a sectional view to show its internal structure. Reveals. The master cylinder 20 is a reservoir-integrated type in which a reservoir 30 is integrally supported on an upper portion of a cylinder body 22. The cylinder body 22 itself has an opening 23 on the cylinder head 22h side, and a cylinder hole 24 extends in the axial direction from the opening 23 to the closed cylinder bottom 22b side. Further, outside the cylinder body 22, there are first and second hollow inner boss portions 41 and 42 at positions axially separated from each other. These bosses connect the connecting portions 31 and 32 of the reservoir 30 to the grommet seal 5.
1, 52 to fit the reservoir 30 to the cylinder body 22. Further, the inside of the reservoir 30 and the inside of the cylinder body 22 (to be precise, the first hydraulic chamber 71 and It also communicates with the second hydraulic chamber 72).

In the cylinder hole 24 of the cylinder body 22, a first piston 61 is arranged on the side close to the opening 23, and a second piston 62 is sequentially arranged in the back of the cylinder body 24 with their axes aligned as one. A second hydraulic pressure chamber 72 is defined between the second hydraulic pressure chamber 62 and the second piston 62, and a first hydraulic pressure chamber 71 is defined between the second piston 62 and the first piston 61. As is known,
A force from the push rod interlocked with the depression of the pedal is applied to the end portion of the first piston 61 on the opening 23 side. Then, the force causes the first piston 61 to move to the cylinder bottom 22.
The hydraulic pressure is generated in the first hydraulic chamber 71 by moving it toward the b side, and the second hydraulic pressure is generated in the second hydraulic chamber 71 in accordance with the movement of the first piston 61.
The piston 62 is also moved to the cylinder bottom 22b side, and hydraulic pressure is also generated in the second hydraulic chamber 72. The first and second hydraulic pressure chambers 71 and 72 are provided in the first and second pistons 6 respectively.
The center valve (shut-off valve) 61 provided on each piston 61, 62 when the brake is inactive without the movement of 1, 62
Since c and 62c are open, they communicate with the reservoir 30 side through the first passage 81 and the second passage 82 that pass through the insides of the first and second boss portions 41 and 42, respectively. However, after the pistons 61 and 62 move, the center valves 61c and 62 are moved as the pistons 61 and 62 move.
c is closed, and the first passage 81 and the second passage 82 are blocked.

The brake pipe in the brake system 10 is of the front-rear type, and the first hydraulic chamber 71 has the brake pipe 1
01 and the first hydraulic pressure control circuit including the anti-skid hydraulic pressure control device 201 to communicate with the left and right first wheel cylinders 301L and 301R on the front wheel side, and the second hydraulic pressure chamber 72 is similarly connected to the brake pipe 102. And second left and right second wheel cylinders 302L, 30 on the rear wheel side through a second hydraulic pressure control circuit including an anti-skid hydraulic pressure control device 202.
I'm contacting 2R. Each anti-skid hydraulic pressure control device 2
01 and 202 have the same configuration for the front wheels and the rear wheels,
As is well known, in addition to a pump device for anti-skid control, a solenoid valve for holding, loosening or filling states, a low pressure reservoir for storing the loosened hydraulic fluid, and a hydraulic pressure check valve. Including etc. These anti-skid hydraulic pressure control devices 201 and 202 operate based on a command from an electronic control unit (not shown) that monitors the state of the wheels when a human brake operation is performed by the pedal to control the brake hydraulic pressure. To do. Further, when automatic brake control including traction control is performed, the same hydraulic pressure control devices 201 and 202 receive commands from the electronic control unit and drive the pump device 90 to drive the wheel cylinders 301L and 301R; 302.
It also functions to control the hydraulic pressure supplied to L and 302R. It should be noted that the brake pipe is not limited to the front-rear type, but it is needless to say that other pipe types such as X type can be applied.

In contrast to such human brake control, during automatic brake control, there is no operation by the brake operating means including the pedal, so the first piston 61 maintains the non-operating position. Therefore, the first hydraulic chamber 71 includes the first passage 81 including the insides of the first boss portion 41 and the connection portion 31.
Through to the reservoir 30 side and remains in the released state. Therefore, in order to enable automatic brake control, the flow of the first passage 81 is restricted as described above while the first piston 61 is not moving, and the first hydraulic chamber 71 It is necessary to introduce a pressure liquid into the inside of the. The tandem master cylinder 20 is provided with a third passage 83 for introducing pressure liquid into the first hydraulic chamber 71 from the outside. The third passage 83 is a passage that starts from the suction connection port provided in the second boss portion 42 and reaches the discharge connection port facing the first hydraulic chamber 71 through the pipe 831. A pump device 90 using an electric motor as a drive source and a check valve 91 on the discharge side of the pump device 90 are provided in the middle of the pipe 831 of the third passage 83.
Are placed.

Attention is now paid to the primary side of the tandem master cylinder 20 in the first embodiment. A center hole 610 is provided at the end of the first piston 61 on the first hydraulic chamber 71 side, and a valve retainer 620 having a U-shaped cross section is provided inside the center hole 610. The valve retainer 620 is
One side is open, while the other side has a partition wall 623.
And the diameter of the partition wall 623 is 0.7 to 0.
An 8 mm orifice 500 is provided. In such a valve retainer 620, the center valve 61c is inserted into the internal space, and the end portion on the opening side presses the end portion of the valve seal 613. Further, the valve retainer 620 supports one end of a valve spring 615 that biases the center valve 61c toward the valve seal 613. The valve retainer 620 itself is supported by the retaining ring 670 that sandwiches the filter 650. The filter 650 includes a cylindrical outer frame 651 and a filter mesh 653 attached to the inner peripheral side of the outer frame 651.
The filter 650 prevents foreign matter from being caught between the orifice 500, the center valve 61c, and the valve seal 613 even if the foreign matter enters the first hydraulic chamber 71 by the pump device 90.

The orifice 500 produces a hydraulic pressure required in the first hydraulic chamber 71 by the pump pressure supplied from the pump device 90 during the automatic brake control due to its throttling action, and also the pump pressure. Is effectively prevented from being transmitted to the ring-shaped space 730 on the side circumference of the center valve 61c and the first piston 61. The ring-shaped space 730 is defined by cup-shaped seal members 750a and 750b that are sealingly connected to the outer circumference of the first piston 61.
It is a space defined between the first piston 61 and the cylinder body 22. Since the pump pressure is not directly transmitted to the ring-shaped space 730 due to the throttling action of the orifice 50, the seal member 750b located on the inner circumference of the head portion 22h of the cylinder body 22 and the seal member 750b are supported. The support ring member 770, the stop ring 773, and the like may have the same configuration as the brake master cylinder in the case of performing only a normal human operation. Although the tandem master cylinder 20 has the orifice 500 on the primary side, when the piston returns, the lip of the cup-shaped seal member 750a elastically deforms, so that liquid can be replenished from the reservoir 30 to the first hydraulic chamber 71. Since it is performed, the return speed of the piston does not slow down.

[0015]

[Modification of First Embodiment] In the tandem master cylinder 20 shown in FIG. 1, a part of the first piston 61 is a cylinder body 2.
In contrast to the piercing type that protrudes from the second head portion 22h, the one shown in FIG. 2 has the first piston 261 entirely inside the cylinder body 222. Furthermore, FIG.
The valve retainer 2620 of
The cylindrical portions are provided on both sides of the partition wall 2623 having the. The cylindrical portion 625 on the side facing the first hydraulic pressure chamber 71 has the center valve 61.
The diameter is larger than that of the cylinder portion 627 on the c side, and the end portion includes an outward flange 625f. Outward flange 6
25f is located outside the opening of the center hole 610 of the first piston 61 and supports the spring bearing 800 of the caged spring. Further, the filter 2650 adjacent to the orifice 500 includes a cylindrical member 2651 and the cylindrical member 2651.
51 and a filter mesh 2653 supported on the bottom side. The tubular member 2651 of the filter 2650 has a size suitable for the inner diameter of the tubular portion 625 of the valve retainer 2620, and a protrusion-shaped concavo-convex coupling portion 655 which is concavo-convexly coupled to the concave portion of the inner periphery of the tubular portion 625 is provided on the outer periphery thereof. is there. Therefore, the filter 2650 is
It can be easily attached to the valve retainer 2620 side. In addition, the tubular portion 625 of the valve retainer 2620 is separate from the other portions of the valve retainer, and the tubular portion 6 is a separate body.
The portion 25 may be provided integrally with the portion of the tubular member 2651 of the filter 2650. In that case, filter 2
The tubular member that holds 653 is configured to be directly concave-convexly coupled to the inner circumference of the central hole 610 of the first piston 261.

[0016]

[Second Embodiment] FIG. 3 is a piping system diagram showing a brake system 210 of a second embodiment, and FIG. 4 is a sectional structural view of a tandem master cylinder 220 used in the system 210. The main points of this brake system 210 different from those of the first embodiment are that a hydraulic control device located in the middle of the front and rear pipes is integrated as a hydraulic control unit 2012, and that the primary side is a plunger type. That is. Therefore, the second embodiment will be described focusing on the parts on the primary side of different types. The other parts are given the same reference numerals as those used in the first embodiment, and their explanations are omitted.

The diameter of the cylinder body 222 of the tandem master cylinder 220 is gradually increased as it goes to the head portion 222h, as compared with the diameter of the portion 2222 on the secondary side. That is, the portion 2221m around the spring receiver 2800 of the caged spring has a medium diameter, the adjacent portion 2221b has a large diameter, and the adjacent portion 2221B has an even larger diameter, and the inner periphery of the opening of the largest portion 2221B has a screw hole. It is 223. First on the primary side
The diameter of the piston 261 is such that the respective portions 222m, 22m
It is smaller than the diameter of any of the inner peripheral holes of 21b and 2221B. Therefore, in order to support and guide the first piston 261, the large diameter portion 2221b has a piston guide 950, and the largest portion 2221B has a lid member 970.
There is each. The lid member 970 is screwed into the screw hole 223, and the front end of the piston guide 950 is attached to the cylinder main body 2.
It is applied to the step on the 22 side. The piston guide 950 and the lid member 970 have a cup-shaped seal member 27 on the inner circumference.
50a and 2750b, and seal members 3750a and 3750b made of O-rings are held on the outer circumferences, respectively. The inner cup-shaped sealing members 2750a and 2750b are
The outer periphery of the first piston 261 is sealingly coupled, and the outer sealing members 3750a and 3750b are sealingly coupled to the inner peripheral wall of the cylinder body 222. With such arrangement of the seal member, a small ring-shaped space 2730 is defined in the side circumference of the first piston 261. The first hydraulic chamber 271 inside the cylinder body 220 includes a plurality of brake loosening holes 2500 provided in the first piston 261.
The communication passage 955 provided in the piston guide 950, the ring-shaped space 2730, and the passage 2207 provided in the cylinder body 220 are sequentially passed to communicate with the inside of the reservoir 230. Here, a plurality of brake loosening holes 2500 are
It is used as an orifice to limit the propagation of pump pressure. Therefore, a plurality of brake loosening holes 2500
Are set so as to have a throttling function corresponding to one orifice having a diameter of 0.7 to 0.8 mm. The communication passage 955 inside the piston guide 950 includes a branch passage 957 that communicates with the back surface of the cup-shaped seal member 2750a, and the working fluid inside the reservoir 230 is transferred to the first liquid by inclining the lip of the seal member 2750a. The pressure chamber 271 can be replenished with liquid.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing a first embodiment of a brake system according to the present invention.

FIG. 2 is a cross-sectional view of a main part showing a modified example of the first embodiment.

FIG. 3 is a piping system diagram showing a second embodiment according to the present invention.

FIG. 4 is an enlarged sectional view showing a main part of a master cylinder used in the second embodiment shown in FIG.

[Explanation of symbols]

10 Brake system 20 tandem master cylinder 22 Cylinder body 24 cylinder holes 30 reservoir 61 First Piston 62 Second piston 71 First hydraulic chamber 72 Second hydraulic chamber 81 First Passage 82 Second passage 83 Third passage 90 Pump device 500 orifice 2500 Brake loosening hole (orifice) 730, 2730 Ring type space

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-172280 (JP, A) JP-A-63-166645 (JP, A) JP-A-63-46958 (JP, A) 149364 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60T ^7/ 12-11/34

Claims (6)

(57) [Claims] 1. A tandem master cylinder in which a first piston and a second piston define a first hydraulic pressure chamber and a second hydraulic pressure chamber inside a cylinder body, and first and second tandem master cylinders, respectively. Reservoirs that communicate with the hydraulic chambers through the first and second passages, respectively, a first wheel cylinder that communicates with the first hydraulic chambers through a first hydraulic control circuit, and a second liquid with the second hydraulic chambers. The tandem master cylinder further includes a second wheel cylinder that communicates through a pressure control circuit and a pump device that communicates with the first hydraulic chamber through a third passage, and the tandem master cylinder further includes a brake operating unit operated by a driver. The first and second pistons move in response to the brake operation by the operating means, and the first and second cutoff valves communicate with the first and second passages accordingly. The brake fluid is supplied from the pump device to the first hydraulic chamber without any manual brake control for changing the state from the closed state to the cutoff state and thereby causing the brake hydraulic pressure and the operation by the brake operating means. Accordingly, a brake system according to two control modes, that is, automatic control for automatically generating a brake fluid pressure, wherein a seal member is seal-coupled to the outer circumference of the first piston, the outer circumference of the cylinder body and the outer circumference of the first piston. A ring-shaped space is formed between the first liquid and the first liquid pressure chamber, the first cutoff valve, and the ring-shaped space to the reservoir. between chamber through to the space of the ring-shaped, in order to obtain the automatic control mode, the first passage opening and closing, or the flow restriction means is arranged to narrow the flow of the first passage, whereby, Serial first fluid pressure chamber
Between the first passage and the reservoir
An automatic control brake system characterized by eliminating the on-off valve to be installed . 2. The brake system according to claim 1, wherein the flow restricting means is an orifice located between the first hydraulic chamber and the first shutoff valve. 3. The brake stem according to claim 2, wherein a filter is provided between the first hydraulic chamber and the orifice. 4. The valve, wherein the first cutoff valve comprises a center valve located on a central axis of the first piston, and a partition is included in a central hole of the first piston facing the first hydraulic chamber. 4. A braking system as claimed in claim 2 or 3 in which there is a retainer and the partition has the orifice. 5. The opening of the center hole of the first piston,
There is a cylindrical member that holds the filter mesh of the filter, and the outer periphery of the cylindrical member has a concavo-convex coupling for concavo-convex coupling with the center hole of the first piston or the inner periphery of the valve retainer fitted in the center hole. Claim 4
Brake system. 6. The first cutoff valve includes a brake loosening hole provided in the first piston and a seal member supported on the cylinder body side, and the seal member is moved along with the movement of the first piston. Is a plunger type that opens and closes the brake loosening hole, and the brake loosening hole functions as the orifice.