DE4244675C2 - Anti-lock braking system - Google Patents

Description

The invention relates to an anti-lock braking system according to the preamble of Claim 1.

State of the art

Fig. 13 shows an anti-lock braking system for use in vehicle braking devices that prevents vehicle wheels from locking when braking (Japanese Patent Application, JP-OS 1-297350; US-4,988,148). In this anti-lock braking system 261 , a pressure control valve with a housing 258 and a slide 259 is used. A master cylinder opening 251 , a wheel cylinder opening 253 and a reservoir opening 257 are provided in the housing 258 . The master cylinder port 251 communicates with a master cylinder 250 connected, the wheel cylinder 253 communicates with a wheel cylinder 252 in communication, and the stock container opening 257 is connected via the first valve 254 to the inlet side of the pump 256 and the reservoir 255 in connection. The pump 256 also receives brake fluid in the reservoir 255 and discharges it into this reservoir 255 . The slider 259 is provided so that it is movable in the housing 258 .

The spool 259 of the pressure control valve 260 connects the master cylinder opening 251 and the wheel cylinder opening 253 when the anti-lock control is not active. In addition, due to the pressure difference resulting from the opening of the first valve 254 at the time of the pressure reduction in the anti-lock control, the slide 259 moves and limits the connection of the master cylinder opening 251 and the wheel cylinder opening 253 , while at the same time connecting the wheel cylinder opening 253 and the reservoir 257 . At the same time, the slide valve 259 supplies brake fluid to the wheel cylinder 252 , which is returned by means of the pump 256 by closing the above-mentioned first valve 254 while the pressure builds up again.

The brake fluid pressure adjusting device 261 is constructed in such a way that, at the time of the re-establishment of brake fluid pressure during an anti-lock operation, both the pulsation movement generated by the pump 256 and the stroke fluctuations generated in the master cylinder 250 (the so-called "kick-back", restoring effect) are prevented. That is, the brake fluid discharged from the pump 256 passes through the pressure control valve 260 in a fixed flow amount without involving the master cylinder 250 and flows out to the wheel cylinder 252 . As a result, the housing 258 has its own pump opening 262 , which is connected to the outlet side of the pump 256 . In addition, during the anti-lock control, the spool 259 limits the connection between the pump opening 262 and the master cylinder opening 251 . Separated from the pressure regulating valve 260 is provided between the master cylinder port 251 and the pump port 262, a channel 263 is provided so that brake fluid is conveyed back in a fixed flow amount by the pump 256 to the master cylinder 250; An opening 264 is provided in this channel 263 . In the above-mentioned construction of the brake fluid pressure control device 261, however, when the opening 264 described above between the master cylinder opening 251 and the pump opening 262 is large, a strong pump pulsation acts on the master cylinder 250 . In addition, if the opening 264 is too small, there are manufacturing problems, e.g. B. increased processing costs, as well as problems such. B. when rubber mixed with the brake fluid clogged the opening 264 . Furthermore, opening 264 changes the flow rate of the brake fluid returned to the master cylinder 250 due to the fluctuation in the outlet pressure of the pump 256 . As a result, the master cylinder 250 generates a stroke fluctuation. Therefore, improvements have been made to the above points.

Japanese UTT, First Publication, Sho 61-3059, has also been disclosed as an anti-lock braking system for use in anti-lock control. In this device shown in FIG. 14, when the anti-lock control pressure increases (renewed pressure build-up), the magnetic control valve 300 comes into a state in which it switches the connection between the master cylinder 301 and the wheel cylinder 302 . In this state, the brake fluid received and discharged from the reservoir 303 by the pump 304 passes from the channel 305 through the switching valve 306 and the channel 307 and back to the wheel cylinder 302 . The switching valve 306 has the construction shown in FIG. 15. This switching valve 306 throttles when 304 discharged brake fluid flows from the pump through the channel 305 in the inner portion and passes through the piston 308 formed in the flow channel 308 a. A pressure difference is thus generated on both sides of the piston 308 . When the valve element 309 moves against the spring force 301 after the movement of the piston 308 , this valve element throttles the connection between the channel 305 on the outlet side of the pump 304 and the channel 311 on the master cylinder side, so that the phenomenon of "kickback" is reduced . Similarly, in this anti-lock braking system, in channel 313 , which bypasses the inlet and outlet side of pump 304 , there is a relief valve 312 that allows excess brake fluid pressure to escape to the inlet side of pump 304 and to reservoir 303 when the outlet pressure of pump 304 is above a predetermined pressure increases, provided. In addition, a check valve 314 is provided separately from the relief valve 312 , which, when the brake is released, returns brake fluid from the reservoir 303 to the master cylinder 301 .

Furthermore, the brake fluid of the reservoir 303 in the above-mentioned device is not normally discharged by the pump during an anti-lock control pressure decrease and pressure increase. This is not a system designed to allow brake fluid to flow in a predetermined flow rate through a pressure control valve to the reservoir 303 or the wheel cylinder 302 . Furthermore, the purpose of this anti-lock braking system should not be to improve the flow control by means of a pressure control valve. In addition, in order to prevent the effects of the outlet pressure of the pump 304 from reaching the master cylinder 301 , a separate valve 306 is required.

If the brake pedal is released during an anti-lock control process in the anti-lock braking system described above, the pump 304 is not driven and the brake fluid remaining in the reservoir 303 can be returned to the master cylinder 301 via the check valve 314 . This can prevent harmful effects on the controllability of subsequent anti-lock control operations. However, there is a problem that the cost of this construction is significantly increased by a check valve 314 separate from the relief valve 312 .

DE 30 10 639 A1 discloses a hydraulic brake system with a Anti-lock control system known. In the known brake system for one Brake circuit a total of four solenoid valves are provided. Despite this, relatively complex construction is a complete decoupling of the two wheel brake cylinders a brake circuit while anti-lock control is running and avoidance of a Reaction on the brake pedal in anti-lock braking operation is not guaranteed. If for example, with the anti-lock control system running, the pressure in a wheel brake cylinder hydraulic fluid flows from the pump into the brake lines a. The pressure continues to propagate into the wheel cylinders, on the way as in  normal braking. It can not be avoided that the pump generated pressure also has a noticeable effect on the master cylinder, even if in DE 30 10 639 A1 is designed that pulsations of the brake pedal should be avoided. Furthermore the hydraulic fluid pressure built up by the pump also has an effect necessarily on a wheel cylinder that is operated in normal operation and currently no anti-lock control is subject. In summary, DE 30 10 can thus be 639 A1 note that the system shown there due to the numerous electromagnetic valves is complex and expensive and nevertheless repercussions of pressure pulsations caused by the Pump caused on the master cylinder can not be completely avoided. Also the decoupling of the anti-lock control for two brake cylinders of the same Brake circuit is not fully implemented despite the complex design.

A similarly constructed anti-lock braking system is described in EP 363 845 A1. There a pressure regulator is shown which regulates the inflow of brake fluid to the wheel brake. in the Normally, a spring pushes it into an end position, creating a connection from the Master cylinder to the wheel brake exists. In the case of an anti-lock control, one opens in the Drain line downstream solenoid valve. Due to the pressure difference above and below the slider moves and connects the wheel brake to the Suction part of the pump. At the same time, access to the master cylinder respectively Pump outlet blocked. In the known anti-lock braking system is between the Wheel cylinder opening and the reservoir opening of the pressure regulator a channel of little Cross section provided, which should ensure that even if the slide the Blocked pressure regulator, brake fluid from the master cylinder to the wheel cylinder are pressed can, to operate the brake at least temporarily.

Starting from the prior art described above, the object of the invention based on an anti-lock braking system with excellent controllability at low cost successive blockage protection processes.

The solution to this problem is specified in the characterizing part of claim 1.

Due to the special design mentioned there, in particular by the Providing the control bypass line and the control valve, brake fluid after one Anti-lock control is immediately returned to the master cylinder.

Advantageous embodiments are specified in the subclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic representation of the structure of an anti-lock braking system according to a first preferred embodiment.

Fig. 2 is a schematic representation of the construction of an anti-lock system according to a second preferred embodiment.

Fig. 3 is a cross section of a relief valve of an anti-lock braking system according to a second preferred embodiment.

Fig. 4 is a schematic representation of the construction of an anti-lock system according to a third preferred embodiment.

Fig. 5 is a schematic representation of the construction of an anti-lock system according to a fourth preferred embodiment.

Fig. 6 is a schematic representation of the construction of an anti-lock system according to a fifth preferred embodiment.

Fig. 7 is a schematic representation of the construction of an anti-lock system according to a sixth preferred embodiment.

Fig. 8 is a schematic representation of the construction of a pressure control valve and a first valve of an anti-lock system according to a seventh preferred embodiment.

FIG. 9 is a cross section along the line XX shown in FIG. 8.

Fig. 10 is a schematic representation of the structure of a modification of an antilock braking system according to a seventh preferred embodiment.

Fig. 11 is a schematic diagram showing the construction of a pressure control valve and a first valve of an anti-lock system according to an eighth preferred embodiment.

Fig. 12 is a schematic representation of the construction of an anti-lock system according to a ninth preferred embodiment.

Fig. 13 is a schematic illustration of the construction of a known anti-lock braking system.

Fig. 14 is a schematic illustration of the construction of another known anti-lock braking system.

Fig. 15 is a cross section showing a switching valve of another known anti-lock braking system.

PREFERRED EMBODIMENTS OF THE INVENTION

A description of the anti-lock braking system according to the first preferred exemplary embodiment of the invention is given below with reference to FIG. 1. Furthermore, the upper / lower part of the figure has been abbreviated to "up / down" in the following description for the sake of simplicity.

In the figure, the master cylinder 1 is connected to the brake pedal 2 , and when this brake pedal 2 is depressed, brake fluid pressure is generated. The wheel cylinder 3 brakes the wheel 4 of the vehicle by the brake fluid pressure. A brake fluid pressure control circuit 5 is also provided, which is connected to both between the master cylinder 1 and the wheel cylinder 3 ; An anti-lock braking system 6 is provided in this brake fluid pressure control circuit 5 . This anti-lock braking system 6 performs an anti-lock control, that is, this anti-lock braking system 6 lowers and increases the pressure of the brake fluid going from the master cylinder 1 to the wheel cylinder 3 depending on the tendency of the vehicle wheel 4 to slip.

A pressure control valve 8 is provided in a channel 7 within the brake fluid pressure control circuit 5 , which is connected to the master cylinder 1 . This pressure control valve 8 includes a housing 10 . This housing 10 has a cylindrical cylinder section 9 , which goes from top to bottom; a plurality of openings are provided on this cylinder section 9 .

These openings mentioned above include the master cylinder opening 11 , the wheel cylinder opening 13 , the reservoir opening 14 and the pump opening 15 .

The master cylinder opening 11 is perpendicular to the axis of the cylinder section 9 and is provided at a predetermined point, which connects it to the master cylinder 1 via the channel 7 .

The wheel cylinder opening 13 lies below the predetermined distance from the master cylinder opening 11 and is connected to the wheel cylinder 3 via the channel 12 of the brake fluid control circuit 5 .

The reservoir opening 14 lies at a predetermined position on the lower section of the cylinder section 9 in the direction of the axis of the cylinder section 9 .

The pump opening 15 lies opposite the master cylinder opening 11 on the same axis.

Furthermore, the above-mentioned wheel cylinder opening 13 is formed from the upper section opening 16 and the lower section opening 17 . The upper section opening 16 is parallel to the master cylinder opening 11 at a distance that is smaller than the predetermined distance of the master cylinder opening 11 . The lower section opening 17 is connected to and lies parallel to the upper section opening 16 on the outside of the cylinder section 9 and lies at a distance which is smaller than the predetermined distance of the upper section opening 16 .

The reservoir opening 14 of the pressure control valve 8 is connected to the reservoir 18 with variable capacity via the channel 19 of the brake fluid pressure control circuit 5 , and an electromagnetic first valve 20 is provided on the channel 19 between the pressure control valve 8 and the reservoir 18 .

To achieve this variable capacity function, the above-mentioned reservoir 18 also includes a reservoir cylinder 21 , a reservoir piston 22 , which is accommodated in the reservoir cylinder 21 as a displaceable element, and a reservoir spring 23 , which loads the reservoir piston 22 with a predetermined force . In addition, the pump opening 15 of the pressure control valve 8 is connected to the reservoir 18 via the channel 24 of the brake fluid pressure control circuit 5 .

The pump 25 is provided on this channel 24 between the pressure control valve 8 and the reservoir 18 . This pump 25 consists of the pump main body 26 , the inlet valve 27 and the outlet valve 28 . The pump main body 26 performs inlet and outlet functions with the aid of a drive motor. The inlet valve 27 between the pump main body 26 and the reservoir 18 only allows brake fluid to flow from the reservoir 18 to the pump main body 26 . The outlet valve 28 between the pump main body 26 and the pump opening 15 only allows brake fluid to flow from the pump main body to the pump opening 15 . This pump 25 is primarily intended to receive brake fluid within the reservoir 18 and to drain this brake fluid to the pump opening 15 of the pressure control valve 8 .

Furthermore, a fixed cylindrical slide 31 is inserted into the housing 10 of the pressure control valve 8 so that it can move up and down. This slide 31 includes an upper section opening 32 , a lower section opening 33 and an inner opening 34 . The upper portion opening 32 is bored centrally in the direction of the axis in a predetermined diameter from the portion of the slider 31 at the upper end to almost the center position that is predetermined. The lower section opening is formed in the same diameter as the axis and the upper section 32 from the lower end section of the slide 31 to almost the central position, which is predetermined, and is normally in communication with the reservoir opening 14 . The upper section opening 32 and the lower section opening 33 are connected to one another at the inner opening 34 , which has a predetermined diameter that is smaller than all of the above-mentioned openings. Furthermore, an opening section 35 of the lower section opening 33 is provided at the lower end with a predetermined value larger than the diameter of the other sections. The upper portion of the spring 36 is inserted into this opening portion 35 . The spring 36 exerts a predetermined force on the slide 31 upwards.

When an anti-lock control is not performed, the upper portion of the spool 31 is in contact with the upper portion of the cylinder portion 9 by the force generated by the spring 36 , and the spool 31 changes to a still state (the state shown in FIG. 1) . On the other hand, when a first electromagnetic valve 20 opens, a pressure drop occurs on both sides in the inner opening 34 due to the brake fluid in the lower section opening 33 , which flows to the reservoir 18 . This pressure drop causes the slide 31 to move downward. This spring 36 is the spring described in claim 1.

The slide 31 includes the first groove section 37 , the first opening 38 , the second opening 39 , the second groove section 41 , the third opening 42 , the third groove section 43 and the fourth opening 44 .

The first groove portion 37 is provided on the outer surface of the slider 31 at a predetermined distance from the upper end, extends around the entire circumference and has a predetermined width. The first opening 38 communicates with the first groove section 37 and the upper section opening 32 . The second opening 39 communicates with the first groove section 37 and the upper section opening 32 . When the slide 31 is in the motionless state, the first groove section 37 communicates with the master cylinder opening 11 and the pump opening 15 . During this time, the master cylinder opening 11 and the pump opening 15 are in direct communication with each other through the first groove section 37 and are connected via the first opening 38 , the upper section opening 32 and the second opening 39 .

The second groove section 41 lies on the outer surface at a predetermined distance from the first groove section 37 , which extends around the entire circumference and has a predetermined width. The third opening 42 communicates with the second groove section 41 and the upper section opening 32 . When the slider 31 is in the still state, the upper section opening 32 and the upper section opening 16 communicate through the second groove section 41 and the third opening 42 ; on the other hand, when the slider 31 is in a state of movement, the connection of the upper section opening 32 and the upper section opening 16 is interrupted.

The third groove section 43 lies at a predetermined distance from the second groove section 41 on the outer surface of the slide 31 , extends over the entire circumference and has a predetermined width. The fourth opening 44 communicates with the third groove section 43 and the lower section opening 33 . When the slide 31 is in a motionless state, the connection of the lower section opening 33 and the lower section opening 17 is interrupted by a third groove section 43 and the fourth opening 44 ; on the other hand, when the slider 31 is in a state of movement, the lower section opening 33 and the lower section opening 17 communicate through the third groove section 43 and the fourth opening 44 .

For the sake of simplicity, the first opening 38 and the second opening 39 have been described separately; however, since the first groove 37 is in the slider 31 , it can be regarded as an opening.

The section between the pump opening 15 and the outlet valve 28 on channel 24 and the section between the first electromagnetic valve 20 and the inlet valve 27 on channel 19 are connected by the first bypass channel 45 . A relief valve 46 is provided on this first bypass channel 45 . This relief valve 46 is designed to open when the brake fluid pressure between the outlet valve 28 and the pump port 15 exceeds a predetermined value. When this relief valve 46 opens, the excess brake fluid pressure escapes to the inlet side of the pump 25 coming from the passage 24 .

The following explains how the anti-lock braking system 6 functions according to the first exemplary embodiment of the invention.

First of all, when the anti-lock control is in the inactive state, the slide 31 of the pressure control valve 8 , as shown in FIG. 1, stands over the master cylinder opening 11 , the first section groove 37 , the first opening 38 , the upper section opening 32 , the third opening 42 , the second groove portion 41 and the upper portion opening 16 with the master cylinder 1 and the wheel cylinder 3 in connection. As a result, pressure is supplied to the wheel cylinder 3 when the brake pedal 2 is pressed. The connection of the fourth opening 44 and the third groove section 43 to all openings is designed so that it is interrupted in the process. In addition, when the brake pedal 2 is depressed, the brake fluid pressure generated by the master cylinder 1 is passed through the pump port 15 of the pressure control valve 8 to the outlet side of the pump 25 and to the relief valve 46 . However, the outlet valve 28 is located in the pump 25 and the opening pressure of the relief valve 46 is also set to a predetermined higher pressure than the brake fluid pressure generated by the master cylinder 1 . As a result, no brake fluid pressure is supplied to the pump main body 26 through the above-mentioned connections.

Instructions are issued by a control unit (not shown in the figure) if, based on information from a vehicle wheel speed sensor (also not shown in the figure), it is determined that the vehicle wheels have come to a tendency to lock. With the help of these instructions, the anti-lock braking system 6 carries out the pressure-reducing process of the anti-lock control. That is, the brake fluid pressure between the master cylinder 1 and the wheel cylinder 3 is lowered. The brake fluid flows in the section surrounded by the lower section opening 33 and cylinder section 9 by opening the electromagnetic first valve 20 into the reservoir 18 , and a pressure difference is thereby generated on both sides of the inner opening 34 of the slide 31 . Due to this pressure difference, the slide 31 counteracts the force of the spring 36 and moves downward, as shown in FIG. 1, and thus cuts off the connection of the second groove section 41 and the lower section opening 16 and thereby limits the connection of the master cylinder opening 11 and the upper section opening 16 (ie reduces it to a tiny connection or cuts it off completely). At the same time, the slide 31 communicates with the wheel cylinder 3 and the reservoir 18 via the lower section opening 17 , the third groove section 43 , the fourth opening 44 , the lower opening 33 and the reservoir opening 14 . As a result, the brake fluid in the wheel cylinder 3 flows into the reservoir 18 , and the brake fluid pressure of the wheel cylinder 3 is thus reduced.

Brake fluid is removed from the reservoir 18 and then drained to the pump opening 15 by the driving force of the pump 25 . This brake fluid flows from the pump opening 15 through the interior of the pressure control valve 8 to the reservoir 18 . In this state, the connection between the master cylinder opening 11 and the pump opening 15 is further restricted by the slide 31 . As a result, the pressure emitted by pump 25 is not fed directly to master cylinder 1 . Further, when pressure is restored in the anti-lock control, brake fluid flowing from the pressure control valve 8 to the reservoir 18 is stopped by closing the electromagnetic first valve 20 , and the spool 31 moves slightly from top to bottom by the pressure in the lower portion opening 33 as In FIG. 1, the slide 31 conducts the brake fluid, which has previously been circulated by the pump 25 , via the upper section opening 32 , the inner opening 34 and the fourth opening 44 from the pressure control valve 8 to the wheel cylinder 3 . The amount of brake fluid flowing to wheel cylinder 3 is a more or less fixed flow amount, depending on the amount in the connection of the first opening 38 and the master cylinder opening 11 and the amount in the connection of the second opening 39 and the pump opening 15 .

Similarly, the relief valve 46 in the first bypass channel 45 in the anti-lock control, when the pressure in the channel 24 between the pump 25 and the pressure control valve 8 exceeds a predetermined pressure, excess pressure in the channel 24 via the first bypass channel 45 to the inlet side of the Pump 25 escape. Brake fluid is normally drained from the pump 25 to the pump opening 15 at a fixed pressure. This brake fluid, which passes through the interior of the pressure control valve 8 , is passed in a fixed flow quantity to the wheel cylinder 3 or reservoir 18 . Thus, since the amount of brake fluid, which returns to the master cylinder 1 is reduced, Hubschwankungen reduce the master cylinder 1 can.

Furthermore, due to the release of excess pressure through the relief valve 46 in the pump 25, there is no operation when the pressure is above a fixed value, and thereby the rotation of the pump 25 and the motor that drives the pump (not shown in the figures) , are kept at a fixed speed. So noises that are unpleasant to the ear are not generated, since noise-producing fluctuations are excluded by the use of the pump 25 and the motor that drives the pump. Together with this, the driving force of the motor driving the pump can be set to a minimum necessary limit value, since excessively high pressure no longer has to be generated by the open valve pressure of the relief valve 46 . Because of this, both the cost and the weight of the engine are equally reduced.

Furthermore, the opening on a channel separate from the pressure control valve 8 no longer has to connect the master cylinder opening 11 and the pump opening 15 ; thus, there are no troubles in which the opening is the cause (for example, when rubber mixed with the brake fluid clogs the opening), and thus the reliability can be improved.

It is also desirable to adjust the pressure of the relief valve 46 to the maximum brake fluid pressure of the vehicle with the valve open.

An anti-lock braking system according to the second exemplary embodiment of the invention is explained below with reference to FIGS. 2 and 3. Furthermore, the main difference between the second embodiment and the first embodiment lies in the relief valve, so that the explanation focuses on the different parts: corresponding parts of the apparatus of the first embodiment are denoted by the same numbers; however, these explanations are omitted.

The above-mentioned anti-lock braking system 6 is a fixed value that is set to the maximum brake fluid pressure of the vehicle, which corresponds to the opening pressure of the relief valve 46 . However, in the above structure, if the pressure of the master cylinder 1 is low, there is a possibility that an amount of brake fluid will return to the master cylinder 1 . Therefore, the anti-lock braking system of the second preferred embodiment means a further improvement of the above point.

With the relief valve 47 of the anti-lock braking system 66 according to the second exemplary embodiment, a branching channel 48 from channel 7 is connected between the master cylinder 1 and the pressure control valve 8 , as shown in FIG. 2. As shown in FIG. 3, this relief valve 47 includes a pump chamber 51 and a master cylinder chamber 52 . The pump chamber 51 includes the insertion opening 49 , which is connected to the outlet side of the pump 25 , and the outlet opening 50 . The master cylinder communication chamber 52 is provided separately from the pump communication chamber 51 , and the communication port 53 is provided in the master cylinder communication chamber 52 as a connection to the passage 48 .

The valve element 55 is provided inside the pump connection chamber 51 . When this valve member 55 rests on the seat 54 formed at the boundary portion of the insertion opening 49 and the inside of the pump connection chamber 51 , this seat 54 is closed. However, when moving in Fig. 3 by inserted from the insertion port 49 brake fluid pressure, the valve element 55 to the left, the valve opens, and the brake fluid can flow into the outlet opening 50th This valve element 55 includes, on the insertion opening 49 side, the tip portion 57 of the valve element spring 56 , which exerts a force on the above-mentioned valve element 55 in the direction corresponding to the right in FIG. 3. In addition, a piston 58 , which is movable to the right and left in FIG. 3, is located within the master cylinder connection chamber 52 . This piston 58 can be pushed to the left in FIG. 3 by the piston spring 60 , which is provided between the piston 58 and the end 59 of the master cylinder connection chamber 52 closest to the pump connection chamber 51 . An axle portion 61 of the piston 58 is inserted into the communication hole 62 provided between the pump communication chamber 51 and the master cylinder communication chamber 52 . The other end 64 of the above valve element spring 56 in the pump connection chamber 51 is seated on the end portion 63 of the axle portion 61 . A seal member 65 , which seals the communication port 62 when the piston 58 is in the inserted state, is provided between the master cylinder communication chamber 52 and the pump communication chamber 51 . Furthermore, the chamber in which the piston spring 60 is provided communicates with the outside air inside the master cylinder connection chamber 52 . The above-mentioned valve element 55 and the piston 58 comprise the valve parts, while the valve element spring 56 and the piston spring 60 comprise the force parts.

Furthermore, the spring constants of the valve element spring 56 and the piston spring 60 are set such that the outlet pressure of the pump 25 increases by a predetermined amount higher than the brake fluid pressure generated by the master cylinder 1 .

In such a construction of the relief valve 47, the piston 58 acts when the brake fluid pressure generated in the channel 7 between the master cylinder 1 and the pressure control valve 8 , which flows from the channel 48 to the relief valve 47 , becomes large, counteracts the force of the piston spring 60 and moves in each case according to the level of brake fluid pressure over a given distance. This design of the relief valve 47 thus reduces the valve element spring 56 and increases the predetermined level of the valve opening pressure for valve element 55 .

By controlling the opening pressure of the relief valve 47 of the anti-lock braking system 66 in this way , the outlet pressure of the pump 25 introduced in the pressure control valve 8 corresponds to the brake fluid pressure generated by the master cylinder 1 . As a result, the pressure load on the pump 25 and the motor that drives the pump 25 can be further reduced compared to the anti-lock braking system 6 of the first exemplary embodiment; Similarly, the amount of brake fluid returning to the master cylinder 1 can be further reduced. Furthermore, the brake fluid of the master cylinder 1 generated by pressing the brake pedal 2 is to be conducted via the pump opening 15 of the pressure control valve 8 to the outlet side of the pump 25 and the relief valve 47 . However, an exhaust valve 28 is provided in the pump 25 , and the relief valve 47 is constructed so that the opening pressure as described above takes a constant high value from the brake fluid pressure of the master cylinder 1 . As a result, there is no supply of brake fluid pressure via the exhaust valve 28 and the relief valve 47 to the pump main body 26 and master cylinder 1 .

An anti-lock braking system according to the third exemplary embodiment of the invention is explained below with reference to FIG. 4. Furthermore, the main difference between the third embodiment and the first embodiment and the second embodiment resides primarily in the relief valve, so the following explanation focuses on the parts that are different; the parts that are similar to the apparatus of the first and second embodiments are given the same numbers, and these explanations are omitted.

In the anti-lock control process of the relief valves 46 and 47 of the anti-lock systems 6 and 66 , according to the above first and second embodiments, brake fluid remains in the reservoir 18 when the brake pedal 2 is released; however, there is a possibility that this brake fluid will hinder the control properties in the next anti-lock control operation. Therefore, the anti-lock braking system 67 according to the third embodiment prevents the brake fluid from remaining in the reservoir 18 (without using the pump 25 ), so that the steerability is not affected in a subsequent anti-lock control operation.

Furthermore, the master cylinder 30 according to the third preferred embodiment is a tandem master cylinder which supplies brake fluid pressure 5 A and 5 B through two brake fluid pressure control circuit systems; the two circle systems are constructed identically; therefore only a circular system 5 A is shown in the drawing.

The relief valve 68 according to the third embodiment has an essentially cylindrical housing 69 , in which the control opening 70 , an outlet opening 71 and an insertion opening 72 are provided. The control opening 70 is provided in a pre-given position perpendicular to the axial direction of the housing 69 . The outlet opening 71 is parallel to the control opening 70 and is provided at a predetermined distance. The insertion opening 72 is provided in the axial direction of the center of the lower portion of the housing 69 . The above-mentioned control port 70 communicates with passage 7 between the master cylinder 1 and the pressure control valve 8 through the branched passage 48 . The insertion opening 72 is connected to the connection point of the channel 24 of the first bypass channel 45 . The outlet opening 71 is connected to the connection point of the channel 19 of the first bypass channel 45 . In addition, an internally threaded portion 73 is formed within the peripheral portion at the upper end of the housing 69 .

The following parts are provided within the housing 69 in order from bottom to top in FIG. 4: first part 74 , second part 75 , third part 76 and fourth part 77 .

The first part 74 includes the conical section 78 and the flange 79 . The tapered portion 78 is formed to taper toward the end that goes into the insertion opening 72 . The flange 79 is provided over the conical section 78 and forms a circular plate. In the middle of the first part 74 , a bore 80 is provided in the axial direction (comprising a section of the insertion opening 72 ).

The second part 75 includes the concave portion 81 , the valve element insertion hole 83 , the outlet opening 84 , the seal groove 85 , the bearing seal groove 86 and the connection opening 87 . The concave portion 81 is provided at the lower end of the second part 75 and thus engages together in the flange 79 of the first part 74 .

The valve element insertion hole 83 , which extends in the axial direction to the center of the second part 75 , is opened from a predetermined depth from below and contains the valve element 82 , which is explained below, so that the valve 82 is movable. The outlet opening 84 is provided in a position approximately equal to the height of the outlet opening 71 of the housing 69 . The sealing groove 85 is provided in a predetermined position on the outer surface of the second part 75 . The bearing seal groove 86 is provided in a given diameter and at a predetermined depth from the upper portion of the second part 75 and extends in the axial direction. The connection hole 87 connects the bearing seal groove 86 and the valve element insertion hole 83, and is thus constructed to have a predetermined diameter which is smaller than the above-mentioned diameter.

The third parts 76 include the convex engagement part 88 , the control opening 89 , the bore 90 , the insertion opening 92 and the sealing groove 89 a. The convex engagement part 88 is provided at the lower end of the third part 76 in the axial direction and is engaged with the upper portion of the above-mentioned second part 75 . Control opening 89 is provided in a position at a predetermined distance above convex engagement part 88 of third part 76 at a height approximately equal to that of control opening 70 . Bore 90 connects control opening 89 and the convex engagement part 88 and thus has a predetermined diameter. Insertion opening 92 is provided with a given depth above and perpendicular to the control opening 89 . One end of the piston spring 91 is inserted into this insertion opening 92 . The sealing groove 89 a is provided over the control opening 89 on the peripheral portion of the third part 76 .

At the peripheral portion of the fourth part 77 , an external thread portion 93 is formed, which is screwed into the internal thread portion 73 of the housing 69 . The first part 74 is placed on the insertion opening 72 of the housing 69 by the externally threaded section 93 screwed into the internally threaded section 73 , and in this state the predetermined sections of the first part 74 , the second part 75 , the third part 76 and of the fourth part 77 each come in or come into contact (the configuration shown in FIG. 4).

In addition, in the valve member insertion hole 83 of the second part 75, when the first part 74 is engaged at the lower end, a valve member 82 formed of a spherical steel ball is provided. At the upper end of this valve element 82 , a valve element spring 94 is provided, which generates a predetermined force on valve element 82 in a direction for closing the bore 80 . Furthermore, the opening pressure of the valve element 82 is only greater by the predetermined force of the piston spring 91 and the valve element spring 94 (will be explained below) than the pressure of master cylinder 1 supplied by channel 48 (that is, the additional pressure of master cylinder 1 in the axial direction, to insert the portion 96 of the piston 95 , which will be explained below).

In addition, a piston 95 is inserted into the connection opening 87 of the second part 75 so that it is movable over a predetermined height. In addition, there is a gap between the connection opening 87 and the piston 95 . From the bottom, this piston 95 includes in sequence: tip section 97 , axle section 98 and insertion section 96 . The tip portion 97 is formed to taper toward the end. The insertion portion 96 is inserted into one end of the piston spring 91 (mentioned below). The piston spring 91 supplies a predetermined force and is provided between the insertion section 96 of the piston 95 and the insertion opening 92 of the third part 76 . It is constructed so that the tip portion 97 of the piston 95 first comes into contact with the valve element 82 by the force generated by the piston spring 91 and then pushes the valve element 92 further in the direction of the insertion opening 72 . In addition, a sealing part 99 is provided in the sealing groove 85 of the second part 75 , which is mounted between the sealing groove 85 and the housing 69 .

In the air space formed by the bearing seal groove 86 and the piston 95 of the second part 75 ge, a bearing seal 100 is used with an approximately horseshoe-shaped cross section with the curved side down. This bearing seal 100 widens when the fluid pressure of the master cylinder connecting chamber 101 is greater than the fluid pressure of the pump connecting chamber 102 (both will be described later), and cuts off the connection of the master cylinder connecting chamber 101 and the pump connecting chamber 102 . On the other hand, when the fluid pressure of the master cylinder connecting chamber 101 is lower than the fluid pressure of the pump connecting chamber 102 , this bearing seal 100 allows the flow of the brake fluid from the pump connecting chamber 102 to the master cylinder connecting chamber 101 through the communication port 87 in the state in which the piston 95 is inserted.

In addition, the sealing part 103 is provided in the sealing groove 89 a of the third part 76 . This sealing part 103 is mounted between the third part 76 and the housing 69 .

Further, the above-mentioned outlet port 84 and the valve element insertion hole 83 basically include the pump communication chamber 102 that communicates with the pump 25 and is provided inside the housing 69 . The control opening 89 and the bearing seal groove 86 basically comprise the master cylinder connection chamber 101 , which is connected to the master cylinder 1 and is provided in the interior of the housing 69 . The valve element 82 and the piston 95 comprise the valve part. The piston spring 91 and the valve element spring 94 comprise the pressing part. The channel 48 , the master cylinder connection chamber 101 , the connection opening 87 and the pump connection chamber 102 basically comprise the second bypass channel.

In the state shown in FIG. 4, the pressure control valve 8 increases the pressure of the wheel cylinder 3 in response to the depression of the brake pedal 2 in normal operation.

Similar to the first embodiment, when the anti-lock control is started, the pump 25 goes into a driving state, and the brake fluid discharged from this pump 25 is regulated at a predetermined high value which is higher than the brake fluid pressure generated by the master cylinder 1 through the relief valve 68 , and the pump opening 15 of the pressure control valve 8 is supplied. That is, the pressure of the master cylinder 1 is supplied from the control port 70 of the relief valve 68 via the passage 48 to the master cylinder connection chamber 101 , and this pressure is intended to act on the insertion portion 96 of the piston 95 in the axial direction. The pressure from the master cylinder 1 and the force supplied by the piston spring 91 should thus act on the piston 95 . The pressure from the master cylinder 1 , the force generated by the piston spring 91 , and the force provided by the valve element spring 94 are all sized to act on the valve element 82 which is brought into contact with the tip portion 97 of the piston 95 . When the brake fluid pressure discharged from the pump 25 to act on the valve element 82 increases beyond the sum of the force of the above-mentioned pressing force from the master cylinder 1 , the driving force from the piston spring 91 and the driving force from the valve element spring 94 the relief valve 68 , the inlet opening 72 , so that excess pressure can escape via the outlet opening 71 and the first bypass duct 45 to the inlet side of the pump 25 . Thus, the brake fluid pressure supplied to the pressure control valve 8 is controlled at a predetermined pressure level that is higher than that of the pressing force from the master cylinder 1 (the driving force of the piston spring 91 and the valve element spring 94 come together). Thereby, to give a concrete example, when the pressing force of cylinder 1 is relatively small, since the opening pressure of the relief valve 68 is low, the relief valve 68 opens easily, and brake fluid escapes to the inlet side of the pump 25 . On the other hand, if the pressing force of the master cylinder 1 is large, since the opening pressure of the relief valve 68 is high, the relief valve 68 does not open easily, and the brake fluid does not easily escape to the inlet side of the pump 25 , due to the approximately linear fluctuations in the opening pressure of the Relief valve 68 an approximately fixed flow of brake fluid flow from the pump 25 to the pressure control valve 8 depending on the pressure force of the master cylinder 1 . As a result, the amount of brake fluid returning to the master cylinder 1 becomes approximately constant, and the pedal kickback is reduced.

In the anti-lock control, in the state where the brake fluid in the reservoir 18 is when the pressure on the brake pedal 2 becomes weaker and the pressing force of the master cylinder 1 decreases, the pressing force of the master cylinder connecting chamber 101 of the relief valve 68 drops to a pressure force level lower than that the pump opening 102 . Thus, the bearing seal 100 eliminates the closing of the communication port 87 in the state in which the piston 95 is inserted therein. The brake fluid in the reservoir 18 is intended to return from the reservoir 18 to the master cylinder 1 via the first bypass passage 45 , the outlet opening 71 of the relief valve 68 , the pump connection chamber 102 , the connection opening 87 , the master cylinder connection chamber 101 , the control opening 70 and the passage 48 . As a result, the brake fluid in the reservoir 18 can return to the master cylinder 1 without actuating the pump 25 . Thus, in a subsequent anti-lock control operation, no harmful effects on the steerability are transmitted. In addition, since the pump 25 only needs to be driven in an anti-lock control operation, unpleasant perceptions (by the operating noise of the pump 25 ) can be eliminated. In addition, the total cost, since a design without a check valve ge separates from the relief valve 68 and with a cheap bearing seal 100 in relief valve 68 is possible. The bearing seal 100 is always provided at a location where a seal is required. In addition, in the third embodiment, a description is given in which a flow valve is used; however, relief valve 68 may be suitable in other systems without a flow valve. Furthermore, as described above, the valve part of the relief valve 68 is not formed from the piston 95 and the spherical valve element 82 , but a construction as a single body is possible. However, by manufacturing them in separate parts, substantially spherical steel balls can be used as valves 82 , which must be accurate, and thus the manufacturing cost can be reduced. In addition, a construction is of course possible in which the piston 95 and the valve element 82 are loaded by the piston spring 91 and the valve element spring 94 as a single body, and not individually. However, by a construction in which force acts on it separately, since a smaller force is sufficient when the above-mentioned parts are separated instead of united, the construction can be made more compact. In addition, since the piston 95 can be returned to its normal fixed position, adverse situations due to brake pedal failure can be prevented.

The fourth embodiment of the invention is explained below with reference to FIG. 5. Furthermore, the main difference of this fourth embodiment from the above third embodiment lies in the relief valve; thus the following description focuses mainly on the sections that are different; the parts that are the same as in the third embodiment are denoted by the same numbers, and their description is omitted. In addition, as in the third exemplary embodiment, the anti-lock braking system of the fourth exemplary embodiment contains two brake fluid pressure control circuit systems 5 A and 5 B, which are constructed approximately identically; therefore only a circular system 5 A is shown and explained; with respect to the other circular system 5 B, only sections that require additional explanation are shown and explained in the figure.

The pump main body 26 of the pump 25 in the brake fluid pressure control circuit system 5 A according to the fourth embodiment is designed so that it is driven together with the pump main body 26 of the pump 25 in the other circuit system 5 B by the same motor 105 and the same cam 106 (as in Fig. 5 shown by the broken line). The construction is such that the pump main body 26 of the other circuit system 5 B releases brake fluid when the pump main body 26 of the circuit system 5 A receives brake fluid; similarly takes the pump main body 26 of the circuit system 5 B brake fluid when the pump main body 26 of the cycle system outputs 5 A brake fluid. Similarly, in the anti-lock braking system 104 according to the fourth exemplary embodiment, a relief valve 107 is provided which allows pressure force to escape to the inlet side of the pump 25 when the pressure force between the pump 25 and the pump opening 15 of the first bypass channel 45 increases to a pressure which is greater than a predetermined pressure is.

The relief valve 107 according to the fourth embodiment includes the pump connection chamber 110 , the master cylinder connection chamber 112 , the seal chamber 113 , the system connection chamber 115 and the connection opening 116 . The pump communication chamber 110 includes the inlet port 108 which communicates with the outlet side of the pump 25 and the outlet port 109 which communicates with the inlet side of the pump 25 . To the master cylinder connection chamber 112 is the return opening 111 , which is connected to the master cylinder 1 of the system 5 A. The master cylinder communication chamber 112 is provided in parallel above and separately from the pump communication chamber 110 . Sealing chamber 113 is provided in parallel above and separate from the master cylinder connection chamber 112 . The system connecting chamber 115 is provided in parallel over and separated from the sealing chamber 113 and includes the control port 114, which communicates with the master cylinder 1 of the system 5 in conjunction B. The communication port 116 passes through the pump communication chamber 110 , the master cylinder communication chamber 112 , the seal chamber 113, and the system communication chamber 115 . In this connection opening 116 , a cylindrically shaped piston 117 , which can move up / down a given distance, is suitably inserted.

A spherical valve member 119 is provided in the above pump connection chamber 110 . This valve member 119 closes the insertion opening 108 when it is seated on the seat 118 in the boundary portion of the insertion opening 108 and the inner part of the pump connection chamber 110 . The valve element 119 , on the other hand, moves upward when the brake fluid pressure supplied to the insertion opening 108 is greater than the predetermined value, and thus opens the valve. In this way, the inlet opening 108 is opened and brake fluid can flow to the inlet side of the pump 25 via the outlet opening 149 . Between this valve element 119 and the wall surface 110 a of the pump connection chamber 110 , a valve element spring 120 , which presses the valve element 119 down, is provided. Similarly, the lower end of the piston 117 lies on the valve element 119 . Furthermore, the opening pressure of this valve element 119 is greater by the predetermined magnitude of the force from the valve element spring 120 than the compressive force of the master cylinder 1 , which acts on the upper tip portion of the piston 117 inserted by channel 121 , which will be described below. Furthermore, the above-mentioned piston 117 and the valve element 119 comprise the valve part, while the valve element spring 120 comprises the pressing force part.

The bearing seal 122 is inserted into the lower part of the master cylinder 112 . At the upper portion of this bearing seal 122 of the master cylinder connection chamber 112 , a return opening 111 is provided which is connected to the channel 48 . The bearing seal 122 functions exactly like the bearing seal 100 in the third exemplary embodiment mentioned above. The channel 48 , the master cylinder 112 , the connection opening 116 and the pump connection chamber 110 basically comprise a second bypass channel.

A sealing ring 123 is provided in the above-mentioned sealing chamber 113 . Through this sealing ring 123 , the connection of the master cylinder connection chamber 112 and the system connection chamber 115 is cut off.

With the anti-lock braking system according to the fourth embodiment, in the anti-lock control, when the pump 25 of the system 5 A to drain the brake fluid moves from a position of maximum intake to a position of maximum discharge, the pump 25 of the system 5 B moves to that To absorb brake fluid from a maximum delivery position to a maximum intake position. As a result, the brake fluid pressure of the master cylinder 1 of the system 5 B, which acts on the upper tip portion of the piston 117 of the relief valve 107 in system 5 A, tends to drop via the channel 121 . Thus, the relief valve 107 of the system 5 A lowers the valve opening pressure depending on the increase in the outlet pressure of the pump 25 of the same system, so that the amount with the valve open and the amount of brake fluid escaping to the inlet side of the pump 25 gradually increase. On the other hand, when the pump 25 of this system 5 A moves to take up brake fluid from the maximum discharge position to the maximum take up position, the pump 25 of the system 5 B moves to release brake fluid from a maximum take up position to a maximum discharge position ; as a result, the brake fluid pressure of the master cylinder 1 of the system 5 B, which acts on the upper tip section of the piston 117 of the relief valve 107 in system 5 A, tends to increase via the channel 121 . Thus, the relief valve 107 of the system 5 A increases the valve opening pressure in response to the decrease in the outlet pressure of the pump 25 of the same system and gradually decreases the amount with the valve open and the amount of brake fluid that escapes to the receiving side of the pump 25 . This reduces the pulsation of the brake fluid discharged to the pump opening 15 of the pressure control valve 8 . System 5 B then follows the same procedure. Therefore, due to the anti-lock braking system 104 , the pulsations of the two pumps 25 of the two systems 5 A and 5 B, which have reverse uptake and delivery phases, cancel out the pulsations of the two pumps 25 .

Therefore, stroke fluctuations of the master cylinder 1 and so-called pedal kickbacks can be effectively reduced, and unpleasant perceptions due to the pump pulsations, such as operating noises, can also be reduced. In addition, this simple construction contains few elements and can therefore be manufactured with low costs. In the above explanation, an example is given in which the pump 25 of the system 25 have the system and the pump 5 5 A B completely opposite receiving and discharging phases. However, even with a slight difference between them, ie incomplete reversal, good results can be achieved.

The fifth embodiment of the invention is explained below with reference to FIG. 6. Furthermore, the fifth embodiment differs from the above-mentioned first embodiment primarily by the relief valve, so that this explanation focuses on different portions, portions similar to the above-mentioned first embodiment being denoted by the same numbers without explanations.

In the anti-lock braking system 125 of the fifth exemplary embodiment, the second bypass channel 126 is provided, which connects the channel 24 between the pump opening 15 and the outlet valve 28 and the master cylinder 1 . A valve mechanism 129 is provided in the first bypass channel 45 and in the second bypass channel 126 . This valve mechanism 129 is a unitary body that is made up of the relief valve 127 (which releases the excess discharge pressure from the pump 25 into the reservoir 18 ) and the control valve 128 (which closes when the master cylinder 1 fluid pressure becomes high due to braking) opens when the master cylinder fluid pressure drops with the brake released).

In this valve mechanism 129 , a pump communication chamber 130 , a seal chamber 131 , a control chamber 132 , a valve chamber 133 , a communication port 134 and a bore 135 (a portion of the second bypass channel 126 ) are provided. The seal chamber 131 is provided separately from the pump connection chamber 130 . The control chamber 132 is separate from the pump connection chamber 130 on the opposite side of the seal chamber 131 . The valve chamber 133 is also provided separately from the seal chamber 131 on the opposite side of the control chamber 132 . The communication port 134 passes through the pump communication chamber 130 , the seal chamber 131, and the control chamber 132 . The bore 135 , on the other hand, connects the control chamber 132 and the valve chamber 133 . Furthermore, the pump connection chamber 130 , the seal chamber 131 , the control chamber 132 , the valve chamber 133 , the connection opening 134 and the bore 135 are all on the same axis.

The pump connection chamber 130 includes the inlet opening 136 and the outlet opening 137 . The insertion opening 136 is seen on the same axis on the side opposite the sealing chamber 131 of the pump connection chamber 130 and is in communication with the channel 24 between the second bypass channel 126 and the outlet valve 28 . The outlet opening 137 is provided perpendicular to the pump connection chamber 130 and communicates with the reservoir 28 of the most bypass channel 45 .

The control chamber 132 consists of the small diameter chamber 138 and the large diameter chamber 139 , which has a predetermined diameter that is larger than the small diameter chamber 138 . The small diameter chamber 138 is closer to the sealing chamber 131 than the large diameter chamber 139 . The large diameter chamber 139 is on the small diameter side of the chamber 139 opposite to that of the sealing chamber 131 . In the large diameter chamber 139 , the control port 140 and the pressure control valve port 141 are provided. The control port 140 is provided in the direction perpendicular to the axis of the large-diameter chamber 139 on the side of the large-diameter chamber 139 opposite that of the small-diameter chamber 138 . This control opening 140 is connected to the master cylinder 1 . The pressure control valve opening 141 is provided opposite the control opening 140 ; this pressure control valve opening 141 communicates with the master cylinder opening 11 of the pressure control valve 8 .

The valve chamber opening 142 is provided in the valve chamber 133 . The valve chamber opening 142 is provided in the direction perpendicular to the axis of the valve chamber 133 , and this valve chamber opening 142 is connected to the outlet side of the pump 25 via the second bypass channel 126 .

The valve element 143 , which has a smaller diameter than the pump connection chamber 130 , is inserted into the pump connection chamber 130 . On this valve element 143 , a valve part 144 is seen on the side of the insertion opening 136 , through which this insertion opening 136 can be closed. On the opposite side of the valve member 144 of the valve member 143 , the spring insertion hole 145 is hen vorgese. A valve element spring 146 that generates a predetermined force is set at one end of the lower portion 147 and inserted into the spring insertion hole 145 .

A control piston 148 is inserted into the connection opening 134 and the control chamber 132 . On this control piston 148 , an axle portion 149 , a piston portion 150 , a contact portion 154 and a rod portion 156 are seen easily. The axle portion 149 is inserted into the connection opening 134 , and together with it, one end of the valve element spring 146 is inserted into the tip portion closest to the pump connection chamber 130 . The piston 150 is provided on the side of the axle section 149 closest to the valve chamber 133 ; this piston portion 150 has a predetermined diameter which is larger than that of the axle portion 149 , and is fitted into the large diameter chamber 139 of the control chamber 132 so that it is movable. Between the piston portion 150 and the end portion 151 of the control chamber 132 , a spring 152 is provided on the side of the sealing chamber 131 , which generates a predetermined force. A contact portion 154 is provided on the side of the piston portion 150 opposite the axle portion 149 . This contact portion 154 may rest on the end portion 153 of the control chamber 132 on the valve chamber 133 side without closing the bore 135 . A rod portion 156 is provided on the side of the contact portion 154 opposite that of the piston 150 . This rod portion 156 is constructed with a diameter smaller than that of the bore 135 and is responsible for opening and closing the control valve member 155 (which will be described later) of the valve chamber 133 . Furthermore, on the outer peripheral portion of the piston portion 150 of the control piston 148, a piston seal 157 is provided, which prevents the leakage of brake fluid that flows over the above-mentioned piston portion 150 .

A control valve element 155 , which can close the bore 135 , is provided in the valve chamber 133 . Between the control valve element 155 and the end portion 158 of the valve chamber 133 opposite the bore 135 , a spring 159 , which generates a given force, is provided. In the sealing chamber 131 , a sealing part 160 is provided, which prevents the leakage of brake fluid from the pump connection chamber 130 through the connection opening 134 into the chamber 138 with a small diameter when the axle section 149 is used.

The above valve element 143 , the valve element spring 146 and the control piston 148 basically belong to the relief valve 127 , while the control piston 148 , the spring 152 , the spring 159 and the control valve element 155 basically belong to the control valve 128 .

With the aid of the anti-lock braking system 125 in the above construction, as shown in FIG. 6, the control piston 148 of the valve mechanism 129 in the non-braking state by the force generated by the spring 152 sets the contact section 154 on the end section 153 the control chamber 132 opposite the valve chamber 133 and stops. Thus, the rod portion 156 of the control piston 148 counteracts the force of the spring 159 and presses the control valve element 155 so that it moves in the opposite direction to the control chamber 132 and bore 135 is opened. In addition, the valve element 143 enters a state in which it moves to the insertion opening 136 .

After a transition from the above-mentioned state to a braking state, this fluid pressure of the master cylinder 1 , when the brake fluid pressure is generated by the master cylinder 1 , passes through the control opening 140 , flows into the control chamber 132 and acts on the piston section 150 of the control piston 148 . The liquid pressure thus passes from the master cylinder 1 through the pressure control valve opening 141 and is guided to the master cylinder opening 11 of the pressure control valve 8 . Similarly, the piston 148 acts by applying the above brake fluid pressure to the piston portion 150 against the force generated by the spring 151 , moving in the direction of the pump connection chamber 130 and coming with the step portion 161 between the large diameter chamber 139 and the Small diameter chamber 138 in contact. This releases the contact between the control valve element 155 and the rod portion 156 of the control piston 148 , and the control valve element 155 closes the bore 135 by the force generated by the spring 159 . On the other hand, the valve element spring 146 is compressed by the moving axis section 149 of the above-mentioned control piston 148 , and by this compression of the valve element spring 146 , the valve element 143 structurally holds the insertion opening 136 in the closed state.

In this state, in an anti-lock control operation, when the outlet pressure of the pump 25 , which is larger than the force generated by the above-mentioned compression of the valve element spring 146 , acts on the valve element 143 , this valve element 143 counteracts the force of the valve element spring 146 , moves into the direction of the control chamber 132 and opens the insertion opening 136 . So the excess outlet pressure of the pump 25 can escape via the first bypass channel 45 to the reservoir 18 . In addition, the outlet pressure of the pump 25 supplied to the pump opening 15 is regulated at an approximately constant speed. On the other hand, the outlet pressure of the pump 25 should also be conducted to the valve chamber 133 via the second bypass channel 126 at this time. However, since the bore 135 of the valve chamber 133 is closed by the control valve element 155 , this outlet pressure is not passed to the master cylinder 1 via the second bypass channel 126 .

During this anti-lock control described above, after the brake is released, when the fluid pressure of the master cylinder 1 decreases, the fluid pressure on the piston portion 150 is also supposed to decrease. As a result, as shown in FIG. 6, the spool 150 moves to the valve chamber 133 by the force generated by the spring 152 and brings its contact portion 154 into contact with the end portion 153 . Thus, the control valve element 155 counteracts the spring 159 and moves in the opposite direction to the direction of the control chamber 132 and thus opens the bore 135 . As a result, the remaining liquid in the reservoir 18 , which is discharged / absorbed by the pump 25, should return directly to the master cylinder 1 via the second bypass channel 126 . Thus, during the anti-lock control, when the brake is released, since the brake fluid discharged to the pressure control valve 8 disappears, the brake fluid flowing to the wheel cylinder 3 also disappears. Therefore, the "overshoot" phenomenon does not occur, and the fluid pressure of the wheel cylinder 3 is quickly lowered upon releasing the brake.

A brake fluid control device according to the sixth embodiment of the invention is explained below with reference to FIG. 7. Furthermore, the sixth embodiment differs from the fifth embodiment primarily in that the opening pressure of the relief valve follows the fluid pressure of the channel 7 generated by the master cylinder; In addition, the relief valve and the control valve are designed individually. Therefore, the following explanation focuses on the different sections.

In the brake fluid control device 163 according to the sixth exemplary embodiment, as in the fifth exemplary embodiment, there is a first bypass duct 45 (which connects the outlet side of the pump 25 and the reservoir 18 as a bypass duct) and a second bypass duct 126 (which acts as a bypass duct duct 24 connects between the pump opening 15 and the outlet valve 28 and the master cylinder 1 ).

A relief valve 164 is provided in the first bypass channel 45 and is described below.

In this relief valve, a pump communication chamber 165 , a sealing chamber 166 , a master cylinder communication chamber 167 and a communication port 168 are provided. The seal chamber 166 is provided separately from the pump connection chamber 165 . The master cylinder 167 is provided on the side of the seal chamber 166 opposite that of the pump connection chamber 165 . The communication port 168 passes through the pump communication chamber 165 , the seal chamber 166, and the master cylinder communication chamber 167 . Further, the pump communication chamber 165 , the seal chamber 166 , the master cylinder communication chamber 167 and the communication port 168 are all arranged in a straight line.

The pump connection chamber 165 contains the inlet opening 169 and the outlet opening 170 . The insertion opening 169 is provided on the side of the pump connection chamber 165 opposite that of the seal chamber 166 , which lies on the same axis as that of the pump connection chamber 165 and is connected to the outlet side of the pump 25 of the first bypass duct 45 . The outlet opening 170 is provided perpendicular to the pump connection chamber 165 .

The master cylinder communication chamber 167 contains the control port 171 and the communication port 172 . The control port 171 is provided in a direction perpendicular to the axis of the master cylinder connection chamber 167 and communicates with the master cylinder 1 . The communication port 172 is provided on the master cylinder communication chamber 167 side from that of the control port 171 .

A valve element 173 , which can close the insertion opening 169 , is provided in the pump connection chamber 165 . Between this valve element 173 and the end section 177 of the pump connection chamber 165 closest to the sealing chamber 166 , a valve element spring 174 is provided, which generates a predetermined force.

A piston 175 is inserted into the communication port 168 , one end of which is connected to the valve element 173 in the pump communication chamber 165 and the other end of which extends into the master cylinder communication chamber 167 .

In addition, a sealing part 176 is provided in the sealing chamber 166, which seals the connection opening 168 with the piston 175 inserted therein.

Furthermore, the above-mentioned valve element and the piston 175 comprise the valve part, while the valve element spring 174 comprises the force part.

On the other hand, a control valve 178 is provided in the second bypass circuit 126 , which closes when the fluid pressure of the master cylinder 1 rises due to the braking and opens when the fluid pressure of the master cylinder 1 drops after the brake is released.

This control valve 178 is explained below. In this control valve 178 , a valve chamber 179 , a control chamber 180 and a bore 181 (the section of the second bypass circuit 126 ) are provided. The control chamber 180 is provided separately from the valve chamber 179 . The bore 181 is provided between the valve chamber 179 and the control chamber 180 and connects the two chambers. Furthermore, the valve chamber 179 , the control chamber 180 and the bore 181 are all arranged on the same axis.

A valve chamber opening 182 is provided in the valve chamber 179 . This valve chamber opening 182 is provided on the same axis as the valve chamber 179 on the side opposite that of the control chamber 178 and is connected to the outlet side of the pump 25 of the second bypass circuit 126 . The control chamber 180 is formed from the small-diameter chamber 183 , the large-diameter chamber 184 , and the communication chamber 185 . The large diameter chamber 184 is provided on the side of the valve chamber 179 of the small diameter chamber 183 and has a predetermined diameter that is larger than that of the small diameter chamber 183 . The communication chamber 185 is provided on the valve chamber 179 side of the large-diameter chamber 184 and has a predetermined diameter that is smaller than that of the large chamber 184 ; similarly, a pressure control valve opening 186 is provided in the direction perpendicular to the axis of the above-mentioned connection chamber 185 at the connection point of the connection chamber 185 and the bore 181 . This pressure control valve opening 186 communicates with the master cylinder connecting chamber 11 of the pressure control valve 8 . In addition, the above-mentioned communication port 172 communicates with the opposite side of the pressure control valve port 186 .

The control valve element 187 , which can close the bore 181 , is provided in the valve chamber 179 . A spring 189 , which generates a predetermined force, is provided between this control valve element 187 and the end section 188 of the valve chamber 179 on the side of the valve chamber opening 182 .

The control piston 190 is inserted into the control chamber 178 and the bore 181 . This control piston 190 has a rod section 191 , a connecting section 192 , a piston section 193 and an axle section 194 . The rod portion 191 is formed in a diameter that is smaller than the bore 181 and can be inserted into the bore 181 and brought into contact with the control valve element 187 . The connecting portion 192 is provided on the rod portion 191 side opposite to that of the valve chamber 179 and constructed in a diameter smaller than that of the connecting chamber 185 . The piston portion 193 is provided on the side of the connecting portion 192 opposite to that of the valve chamber 179 and is inserted into the large-diameter chamber 184 so that it is movable. The axle portion 194 is seen on the side of the piston portion 193 opposite that of the valve chamber 179 and has a diameter that is smaller than that of the chamber 183 with a small diameter. Furthermore, between the piston section 193 and the end section 195 of the chamber 183 with a small diameter compared to that of the valve chamber 179, a spring 196 is provided, on the inside of which the axle section 194 is inserted, and which generates a predetermined force. Furthermore, a piston seal 197 is provided on the outside of the piston section 193 of the control piston 190, which prevents leakage of brake fluid through the chamber 184 with a large 31241 00070 552 001000280000000200012000285913113000040 0002004244675 00004 31122m diameter when the piston section 193 is inserted.

In the non-braking state as shown in FIG. 7, spool 190 of control valve 178, by force generated by spring 196 , contacts piston portion 193 with step portion 198 between large diameter chamber 184 and connecting chamber 185 and stops there. At this time, the control valve member 187 counteracts the force generated by the spring 189 through the rod portion 191 of the control piston 190 , moves in the opposite direction to the direction of the control chamber 180, and opens the bore 181 . During this time, the valve element 173 of the relief valve 164 also covers the insertion opening 169 by the force generated by the valve element spring 174 .

After the above-described state is switched to the braking state, when brake fluid pressure is generated by the master cylinder 1 , this fluid pressure of the master cylinder 1 acts on the piston section 193 and the connecting section 192 of the control valve 178 . As a result, the control piston 190 counteracts the force of the spring 196 and moves in the opposite direction to the direction of the valve chamber 179 . When this occurs, the spool 190 is to come into contact with the step portion 199 between the large diameter chamber 184 and the small diameter chamber 183 . Thus, the contact between the control valve element 187 and the rod section 191 of the control piston 190 is released . When this happens, the control valve element 187 covers the bore 181 by the force generated by the spring 189 . On the other hand, at this time, since the fluid pressure of the master cylinder 1 acts on the piston 175 protruding from the master cylinder connection chamber 167 , the relief valve 164 is intended to keep the insertion port 169 closed by the fluid pressure of the master cylinder 1 and the force of the spring 175 .

In the above state, when the anti-lock control is performed, when the discharge pressure of the pump 25 exceeds the sum of the force of the liquid pressure from the master cylinder 1 on the piston 175 and the force generated by the valve element spring 174 , the valve element 173 of the relief valve 164 moves to the master cylinder connecting chamber 167 and this opens the insertion opening 169 . Excess outlet pressure of the pump 25 can escape through the first bypass circuit 45 to the reservoir 18 . Thereby, the outlet pressure of the pump 25 , which is to be supplied to the pump opening 15 of the pressure regulating valve 8, is to be regulated at approximately the same level as the sum of the pressure force of the master cylinder 1 and the predetermined force generated by the valve element spring 174 . At this point in time, the outlet pressure of the pump 25 is to be conducted via the second bypass circuit 126 to the valve chamber 179 of the control valve 178 ; however, since the bore 181 is closed by the control valve element 187 , there is no circulation of this outlet pressure to the master cylinder 1 via the second bypass circuit 126 .

During the anti-lock control described above, after releasing the brake when the fluid pressure of the master cylinder 1 decreases, the fluid pressure on the piston portion 193 and the connecting portion 192 of the control piston 190 is also to decrease. Thereby, the spool 190 moves toward the valve chamber 179 by the force generated by the spring 196 and, as shown in FIG. 7, brings the spool portion 193 into contact with the end portion 198 of the control chamber 180 . The control valve element 187 thus counteracts the force of the spring 189 , moves in the opposite direction to the direction of the control chamber 180 and opens the bore 181 . The residual liquid in the reservoir 18 which is picked up / drained from the pump 25 is thus intended to return directly to the master cylinder 1 via the second bypass circuit 126 . As a result, similarly to the fifth embodiment during the anti-lock control, when the brake is released, since the brake fluid discharged to the pressure control valve 8 disappears, the brake fluid flowing to the wheel cylinder 3 disappears in a similar manner. Therefore, the overshoot phenomenon does not occur, and the fluid pressure of the wheel cylinder 3 can be quickly lowered upon releasing the brake.

The anti-lock braking system according to the seventh exemplary embodiment of the invention is explained below with reference to FIGS. 8 and 9. Furthermore, the seventh embodiment differs from the second embodiment primarily in a section of the pressure control valve, so that the following explanation focuses on this different section, omitting details of the parts similar to the device according to the second embodiment and denoted by the same numbers .

In the anti-lock braking system 200 according to the seventh exemplary embodiment, the master cylinder opening 11 is constructed in a predetermined diameter that is smaller than that of the pump opening 15 . Thus, when the slider 31 changes into a moving state, the first groove 37 is designed so that, in a state in which it is not directly connected to the master cylinder opening 11, it is connected to the pump opening 15 through its end portion against the direction of movement (the upper one Part in Fig. 8) is related.

Furthermore, the pump 25 is normally in the drive state during the anti-lock control. When the slide 31 moves, the first groove 37 of the slide 31 should establish a connection to the pump opening 15 through the end section of the first groove 37 against the direction of movement. At this time, since the diameter of the master cylinder opening 11 is constructed in a predetermined diameter which is smaller than that of the pump opening 15 , the master cylinder opening 11 is intended to extend from the outer peripheral portion of the slider 31 between the master cylinder opening 11 and the first groove 37 and the inner peripheral portion of the cylinder 9 of the housing 10 formed gap 201 can be easily connected without being directly connected to the first groove 37 . As a result, the brake fluid discharged from the pump 25 flows when the pressure is released with the opening of the normally closed electromagnetic valve 20 from the pump opening 15 via the first groove 37 , the second opening 39 , the upper section opening 32 , the inner opening 34 , the lower section opening 33 and the Reservoir opening 14 by extraction at inner opening 34 in an approximately constant flow rate to reservoir 18 . In addition, when the electromagnetic first valve 20 closes and the pressure of the pump 25 is increased again, brake fluid discharged flows via the first groove 37 , the second opening 39 , the upper section opening 32 , the inner opening 34 , the lower section opening 33 , the fourth opening 44 , the third Groove 43 and the lower section part 17 of the wheel cylinder opening 13 in an approximately constant flow quantity by extraction at the inner opening 34 from the pump opening 15 to the wheel cylinder 3 . At the same time, a minute part of the brake fluid discharged from the pump 25 is drawn out through the gap 201 formed from the above-mentioned outer peripheral portion of the slide 31 and the inner peripheral portion of the housing 10 and is intended to return to the master cylinder 1 in an approximately constant flow rate (see FIG. 9). .

Thus, the above-mentioned gap 201 becomes a second opening connecting the pump opening 15 and the master cylinder opening 11 and prevents unpleasant feelings on the pedal, such as. B. Pedal kickback. In addition, a passage for connecting the master cylinder opening 11 and the pump opening 15 and an outer opening in the housing 10 are no longer required. As a result, the entire body of the anti-lock braking system 200 can be made more compact, and the manufacturing cost can be reduced.

In addition, in this exemplary embodiment, the relief valve 47 (see FIG. 4) should regulate the pressure to be supplied by the pump 25 to the pump opening 15 at a predetermined pressure level which is greater than the pressure force of the master cylinder 1 . Due to this, when the outlet pressure of the pump 25 is larger than the pressing force of the master cylinder 1 , the difference between the brake fluid pressure of the master cylinder 1 and the brake fluid pressure supplied to the pressure control valve 8 via the relief valve 47 becomes constant. This brake fluid with this pressure difference should pass through the inner opening 34 and the above-mentioned gap 201 . Therefore, fluctuations in the pressing force supplied to the master cylinder 1 through the gap 201 described above can be effectively prevented. Similarly, the relief valve 47 is intended to prevent unnecessary increase in the brake fluid pressure between the outlet side of the pump 25 and the pressure control valve 8 .

A modified example of the seventh embodiment as shown in FIG. 10 is described below. Furthermore, this modified example is a unitary body formed from the above-mentioned pressure regulating valve 8 and the electromagnetic first valve 20 , the respective construction of which is the same as in the exemplary embodiments described above.

The pressure control valve 8 is inserted into the sleeve (housing) 202 . In this sleeve 202 , a master cylinder opening 11 , a wheel cylinder opening 13 and a pump opening 15 are all provided in predetermined positions. This sleeve 202 is inserted both in the slide 31 and in the opening 204 of the housing 203 . The opening section 205 of the housing 203 is to be closed by the closing part 206 , and the sleeve 202 is fastened to the housing 203 . The master cylinder opening 11 of the sleeve 202 communicates with the channel 211 of the housing 203 , and this channel 211 in turn communicates with the master cylinder. The wheel cylinder opening 13 is connected to the channel 209 of the housing 203 via a filter 210 , and this channel 209 is in turn connected to the wheel cylinder. In addition, the pump opening 15 is connected to the channel 207 of the housing 203 via the filter 208 : This channel 207 is in communication with the pump. In addition, an opening section 213 at the lower part of the sleeve pump opening 202 in FIG. 10 is connected to the reservoir opening 14 , which is accommodated in the closing part 206 ; In this closing part 206 an electromagnetic first valve 20 is provided, which communicates with the channel 214 , which in turn is connected to the reservoir opening 14 , and interrupts it. This electromagnetic first valve 20 consists of an armature 216 , on which the valve section 215 , which communicates with and cuts off the channel 214 , is provided. The electromagnetic portion 217 , which magnetically moves this armature 216 and communicates with the channel 214 , and the spring 218 , which applies a force to the armature 216 in the state in which the electromagnetic portion 217 is not magnetized, is included With the help of anchor 216, channel 214 .

An anti-lock braking system according to the eighth exemplary embodiment of the invention is explained below with reference to FIG. 11. Furthermore, the eighth embodiment differs from the seventh primarily in a portion of the spool of the pressure control valve so that the explanation mainly focuses on this different portion and explanations of parts similar to those described in the seventh embodiment and designated by the same numbers are omitted.

On the outer peripheral portion of the slide 31 in the pressure control valve 8 of the anti-lock braking system 219 according to the eighth exemplary embodiment, a tiny keyway 220 is provided at a predetermined distance higher than the first groove portion 37 around the entire circumference. This tiny keyway 220 does not open the master cylinder opening 11 and the pump opening 15 when the anti-lock device is not operated and the slide 31 is in a motionless state; when an anti-lock control is executed and when the slider 31 is in a state of movement, this tiny keyway 220 opens so that a minute connection is made between the master cylinder opening 11 and the pump opening 15 .

As shown in FIG. 11, thus, as in the seventh embodiment, during the anti-lock control when the spool 31 of the control valve 8 moves, the first groove 37 communicates with the pump port 15 in the moving direction by means of the tip portion of the spool 31 . Simultaneously, the slider 31 minimal across the gap 201 between the slider 31 and the master cylinder port 11 is connected to the above-mentioned master cylinder port. 11 The tiny keyway 220 thus creates a tiny connection between the pump opening 15 and the master cylinder opening 11 .

Thus, the gap 201 between the master cylinder opening 11 and the first groove 37 and the minute groove 220 form a second opening. As a result, a portion of the brake fluid drained from the pump 25 to the pump opening 15 via the relief valve 47 (see FIG. 4) is to be pressed out and returned to the master cylinder 1 at an approximately constant flow rate. As a result, an unpleasant pedal kickback can be prevented, similarly to the seventh exemplary embodiment, and a channel connecting the master cylinder opening 11 and the pump opening 15 and the outer opening to be provided in the housing 10 is no longer required. As a result, the anti-lock braking system 219 can be made more compact and the manufacturing cost can be reduced.

Furthermore, since the size of this tiny keyway 220 is easy to change, modifications to the size of the flow path area via the brake fluid flowing through the pressure control valve 8 and returning to the master cylinder 1 can be made. That is, the flow amount of brake fluid returning to the master cylinder 1 can be modified. Therefore, if detection of the anti-lock control state by a pedal is preferred, a pedal kickback can be constructed over an area where no uncomfortable perception occurs. In addition, because of this tiny keyway 220 , as shown in FIG. 11, even if, for example, the slider 31 is fixed, safety is an advantage because small connections of each opening can be maintained.

The ninth embodiment of the invention is explained below with reference to FIG. 12. Furthermore, the ninth embodiment differs from the third embodiment in the construction of the relief valve, so that the following explanation primarily relates to this different section, the similar sections described in the third embodiment being designated by the same numbers.

The relief valve 271 of the anti-lock braking system 270 according to the ninth exemplary embodiment has an approximately cylindrical housing 272 . A control opening 273 is formed on the upper section of this housing 272 and lies perpendicular to the direction of the axis of the housing 272 . This control opening 273 connects the inside of the housing 272 to the master cylinder 30 . In a predetermined position in the middle of the housing 272 , an outlet opening 274 is provided which is perpendicular to the direction of the axis of the housing 272 . This outlet opening 274 connects the interior of the housing 272 to the inlet side of the pump 25 and the reservoir 18 . At the lower end portion of the housing 272 , an insertion opening 275 is provided which is in the direction of the axis of the housing 272 . This insertion opening 275 connects the inside of the housing 272 with the outlet side of the pump 25 .

In a predetermined position lower than the outlet opening 274 of the housing 272 , a circular-shaped closure 276 is formed, which goes radially inwards. On the upper side of the closure 276 , a piston 277 is provided, which is displaceable over a predetermined range. The piston 277 has a cylindrical columnar slidable portion 278 which is slidable along the inner peripheral surface of the housing 272 , and a rod portion 279 which protrudes upward from the above slidable portion 278 . The rod portion 279 has a diameter that is less than the diameter of the slidable portion 278 . A flange 280 is formed in a predetermined position in the center of the rod 279 . The flange 280 has a diameter larger than the rod section 279 , but smaller than the displaceable section 278 . In addition, a connecting opening 281 is formed in the displaceable section 278 of the piston 277 . This connection opening 281 is cut in the direction of the central axis of the slidable portion 278 from the lower end of the portion of the above-mentioned slidable portion 278 to a predetermined position in the middle and goes in a vertical direction. At a point on the circumference of the displaceable section 278 at which the connection opening 281 opens, a round groove 282 is provided. Normally, the connection opening 281 communicates with the outlet opening 274 through this groove 282 without being dependent on the position of movement of the piston 277 . A connection between the insertion opening 275 and the outlet opening 274 is thus possible through the connection opening 281 . Furthermore, a circular sealing groove 283 is provided on the outer peripheral portion between the groove 282 of the slidable portion 278 and its lower end portion. In the rod section 279 between the displaceable section 278 of the piston 277 and the flange 280 , a circular bearing seal 284 with a U-shaped cross section is inserted with the bend downwards. In addition, a bearing seal 284 with a U-shaped cross section is inserted into the sealing groove 285 of the piston 277 with the bend upwards.

Further, in the ninth embodiment, the master cylinder connection chamber 286 is formed from the portion outlined by the housing 272 , the upper portion of the piston 277 and the bearing seal 284 . The connection opening 287 is formed from the inner peripheral surface of the housing 272 from the slidable position in the upper end portion of the bearing seal 284 to the upper end portion of the outlet opening 274 ge. The pump connection chamber 288 is formed from the interior of the housing 272 under the outlet opening 274 . The connection opening 287 varies depending on the movement of the piston 277 .

Thereby, the above-mentioned outlet port 274 is located on a portion of the pump connection chamber 288 which is inserted into the piston 277 , while the insertion port 275 is provided on a section of the pump connection chamber 288 which is not inserted in the piston 277 .

The above bearing seal 284 allows brake fluid to flow from the outlet port 274 side to the master cylinder connecting chamber 286 side when the fluid pressure of the master cylinder connecting chamber 286 is lowered. In addition, when the pressing force of the valve chamber 289 outlined by the pump connection chamber 288 and the piston 277 is high, the bearing seal 285 prevents brake fluid from flowing along the outer surface of the piston 277 from the valve chamber 289 to the outlet port 274 side.

A spring 290 including the pressing member is provided between the flange 280 of the piston 277 and the upper surface of the housing 272 in a state where the rod portion 279 is inserted therein. The piston 277 brings the lower end surface into contact with the shutter 276 by the pressing force of the spring 290 .

The valve element 291 is provided in the valve chamber 289 . The valve member 291 has the flange 292 , which has a slightly smaller diameter than the inner circumference of the housing 272 , the support 293 , which is formed on the side of the piston 277 of the above-mentioned flange 292 , and the convex portion 294 , which on the side the insertion opening 275 of the above-mentioned flange portion 292 is formed. The post 293 has a diameter smaller than that of the flange 292 by a predetermined amount, and the convex portion 294 accordingly has a diameter smaller than that of the flange 292 by a predetermined amount.

In the support 293 , a spherical valve portion 295 is attached and gela gert that it protrudes from the piston 277 . A contact spring 296 is provided between the flange 292 of the valve element 291 and the lower end surface of the housing 272 , in which the convex portion 294 is inserted. In the state in which the piston 277 is in contact with the closure 276 , the valve element 291 is pressed by the contact spring 296 , so that the valve section 295 comes into contact with the piston 277 and closes the connection opening 281 . In this state, a predetermined distance is maintained between the flange 292 and the closure 276 . Furthermore, in the ninth exemplary embodiment, the piston 277 , the valve element 291 and the contact spring 296 comprise the valve part.

With the construction of an anti-lock braking system 270 according to the ninth embodiment, when the force from the outlet pressure of the pump 25 pushing the piston 277 upward, the sum of the force of the brake fluid pressure moves to the side of the master cylinder 30 pushing the piston 277 downward , and the pressing force of the spring 290 exceeds, the piston 277 to the master cylinder connecting chamber 286 side . At this point, the valve member 291 in the state where the communication port 281 is closed by contact with the piston 277 by the pressing force of the contact spring 296 , moves as a body with the piston 277 over the interval until the piston 277 gap happens between the closure 276 and the flange 292 of the valve element 291 : As a result, the capacity of the master cylinder connection chamber 286 decreases. By reducing this capacity, an amount of brake fluid returns to the master cylinder 30 , and the brake pedal 2 similarly goes back a little way so that the driver knows that the anti-lock control is active. In the state in which the movement of the valve member 291, which is by the urging force of the contact spring 296 with the shutter 276 in contact, is regulated, the piston 277 separates when the piston continues to move 277 away from the valve member 291, and in Above piston 277 formed connection opening 281 opens. The insertion opening 275 and the outlet opening 274 are thereby connected, and the excess pressure of the brake fluid can escape to the inlet side of the pump 25 . On the other hand, when the outlet of the pump 25 is exhausted, the piston 277 moves to the side of the valve chamber 289 and comes into contact with the valve member 291 which has been in contact with the shutter 276 so that it closes the communication port 281 . In this state, the piston 277 and the valve element 291 move over a predetermined distance as one body until the piston 277 comes into contact with the shutter 276 . The movement of the piston 277 , when this connection opening 281 is in the closed state, reduces the capacity of the valve chamber 289 and the brake fluid that was in the valve chamber 289 can flow out of the insertion opening 275 .

Thus, even if the pump 25 periodically discharges brake fluid, the moment the outlet of the pump 25 is stopped, the above-mentioned flow of the brake fluid is generated to the outside, and a continuous flow of the brake fluid from the outlet side of the pump 25 becomes receive. Thus, the liquid outlet flow of the pump 25 is flattened and then supplied so that there is a measurable improvement in the effective proportion of the pump 25 .

In addition, the valve member 291 normally receives high fluid pressure from the pump outlet side and is pushed down by the piston 277 so that the sealability is high, and the unexpected leakage from the outlet side of the pump 25 to the inlet side of the pump 25 can be prevented. In addition, the bearing seal 285 , which self-seals from the valve chamber 289 side to the outlet 274 side, is provided between the groove portion 282 of the piston 277 and the lower end portion at the outer peripheral portion, thereby causing unexpected leaks from the outlet side of the pump 25 to the inlet side of the pump 25 can be prevented via this section.

Furthermore, if the improvement of the effective portion of the pump 25 and ensuring the sealability of the valve element 291 are the main goals, designs are possible in which the bearing seal 284 is possible at a separate location or not at all.

In addition, in the ninth embodiment, a device in which a Flow valve is used, given as an example and explained; but it is also possible Lich, this device in other systems in which no flow valve is used use.

Claims (5)

1. An anti-lock braking system for a vehicle brake, comprising:
a master cylinder ( 1 , 30 ), at least one brake circuit and wheel cylinder ( 3 );
an exhaust valve ( 20 ) that is opened to lower the brake pressure and closed to raise the brake pressure;
a reservoir ( 18 ) for receiving skipped brake fluid;
a pump ( 25 ) having an inlet side for drawing brake fluid from the reservoir and an outlet side for dispensing brake fluid;
a pressure control valve ( 8 ) connected to the master cylinder ( 1 , 30 ), the wheel cylinder ( 3 ), the reservoir ( 18 ) and the pump ( 25 ), which builds up and reduces the brake pressure in the wheel cylinder ( 3 ),
wherein the pressure control valve ( 8 ) has a housing ( 10 ) with:

• a) with the master cylinder ( 1 , 30 ) communicating with the master cylinder opening ( 11 );
• b) a wheel cylinder opening ( 13 ) connected to the wheel cylinder ( 3 );
• c) via the outlet valve ( 20 ) with the inlet side of the pump ( 25 ) and the reservoir ( 18 ) in connection reservoir opening ( 14 );
• d) a pump opening ( 15 ) which communicates with the outlet side of the pump ( 25 );
• e) a slide ( 31 ) which is pressed into its rest state by a spring ( 36 ), in which it connects the master cylinder opening ( 11 ) and the wheel cylinder opening ( 13 ), the slide ( 31 ) being one at a time on both Sides through the opening of the outlet valve ( 20 ) pressure difference to brake pressure decrease moves, and thereby
  • a) restricts the connection between the master cylinder opening ( 11 ) and the wheel cylinder opening ( 13 ),
  • b) the wheel cylinder opening ( 13 ) and the reservoir opening ( 14 ) connects and
  • c) restricts the connection between the pump opening ( 15 ) and the master cylinder opening ( 11 ),

the slide (31) passes in the braking pressure decrease, through the internal opening (34) in an approximately constant flow rate of the pump (25) discharged brake fluid from the pump opening (15) to the storage container opening (14), and wherein a brake pressure increase, on the internal opening ( 34 ) from the pump ( 25 ) released brake fluid from the pump opening to the wheel cylinder opening ( 13 ), characterized in that a control bypass line ( 126 ) connects the outlet side of the pump ( 25 ) to a control valve ( 128 , 178 ) which between the master cylinder ( 1 ) and the pressure control valve ( 8 ), which control valve ( 128 , 178 ) closes the control bypass line ( 126 ) when the brake medium pressure between the master cylinder and the pressure control valve ( 8 ) is greater than a predetermined value, and the bypass line opens when the brake fluid pressure is less than the specified value. 2. The anti-lock braking system of claim 1, further comprising:
a relief bypass line ( 45 ) connecting the reservoir ( 18 ) to the outlet side of the pump ( 25 ) and
a relief valve ( 127 , 164 ) in the relief bypass line ( 45 ) to discharge excessive pump pressure. 3. An anti-lock braking system according to claim 2, wherein the control valve ( 128 , 178 ) and the relief valve ( 127 , 164 ) are connected in series. 4. The anti-lock braking system according to claim 2, wherein the control valve ( 178 ) comprises:
a control piston ( 190 ) exposed to brake fluid,
a control spring ( 196 ) which presses the control piston ( 190 ) against the brake medium pressure,
a valve ( 187 ) for opening and closing the control bypass line ( 126 ),
a valve spring ( 189 ) that urges the valve ( 187 ) in a direction to close the control bypass line ( 126 ), and
a rod ( 191 ) which urges the valve ( 187 ) against the valve spring ( 189 ) to open the control bypass line ( 126 ) by the force of the control spring ( 196 ) and which, when the control piston ( 190 ) releases brake fluid pressure from the master cylinder ( 1 ) and moves against the control spring ( 196 ), releasing pressure to the valve ( 187 ) to close the control bypass line ( 126 ). 5. An anti-lock braking system according to claim 3, comprising:
a spool ( 148 ) exposed to brake fluid pressure,
a control spring ( 152 ) which presses the control piston ( 148 ) against the brake medium pressure,
a valve ( 155 ) for opening and closing the control bypass line ( 126 ),
a valve spring ( 159 ) that urges the valve ( 155 ) in a direction to close the control bypass line ( 126 ), and
a rod ( 156 ) which applies pressure to the valve ( 155 ) and moves it against the valve spring ( 159 ) to open the control bypass line ( 126 ) by the force of the control spring ( 152 ), and when the control piston ( 148 ) Receiving brake fluid pressure from the master cylinder ( 1 ) and moving against the control spring ( 152 ), releasing pressure to the valve ( 155 ) to close the control bypass line; and
the relief valve ( 127 ),
an axial member ( 149 ) disposed on the spool ( 148 ) on the side opposite the rod ( 156 )
a valve member ( 144 ) acted upon by the pump outlet pressure to open and close the relief bypass line ( 45 );
and a valve member spring ( 146 ) disposed between the axial member ( 149 ) and the valve member ( 144 ) to urge the valve member ( 144 ) in a direction to close the relief bypass line ( 45 ) and which is compressed when the spool ( 148 ) takes up brake fluid pressure and moves against the force of the control spring ( 152 ).