GB2225168A

GB2225168A - Electromagnetic valve device

Info

Publication number: GB2225168A
Application number: GB8923013A
Authority: GB
Inventors: Toshifumi Maehara
Original assignee: Akebono Brake Industry Co Ltd; Akebono Research and Development Centre Ltd
Current assignee: Akebono Brake Industry Co Ltd; Akebono Research and Development Centre Ltd
Priority date: 1988-10-28
Filing date: 1989-10-12
Publication date: 1990-05-23
Also published as: FR2638506B1; DE3935946A1; FR2638506A1; GB8923013D0

Description

95168 i_ 1-4- ELECTROMAGNETIC VALVE DEVICE

The present invention relates to an electromagnetic valve device capable of controlling the fluid pressure to a brake for a vehicle. There is a disclosure about such an electromagnetic valve device, for example, in Japanese Patent Utility Model Laid-open No. 1986-82185.

The electromagnetic valve device is arranged to be disposed between a passage for liquid on the brake cylinder side and a passage on the master cylinder side, the electromagnetic valve device acting to maintain the fluid pressure in an anti-lock control device of a brake system for a vehicle.

During anti-lock brake control, liquid under pressure is supplied from the passage on the master cylinder side to the passage on the brake cylinder side via the electromagnetic valve device at the early stage of the braking operation, while liquid is arranged to be returned to the master cylinder via the electromagnetic valve device when the braking is finished. AS a result, since the liquid needs to pass back through the electromagnetic valve device when the brake is released, an excessive resistance can be generated, causing the returning speed of the liquid to be excessively low.

In order to avoid the problem, that is, in order to improve the return response, a check valve is disposed between the passage on the brake cylinder side and the -2passage on the master cylinder side, the check valve acting as a bypass capable of raising the returning speed of the liquid.

It has been proposed to employ a structure arranged such that the return stroke of the valve is arranged to be relatively large so as to enlarge the passage and to reduce the resistance.

In the known devices, an excessive space must be provided for disposing the check valve in the electromagnetic valve device, or the capacity of the solenoid must be enlarged for enlarging the lift of the valve, for the purpose of raising the valve lifting speed, another necessity being that the return spring must be strengthened.

Thus, the size of the electromagnetic valve device must be enlarged with the countermeasures described above.

However, the enlargement of the size of the electromagnetic valve devices generates a disadvantage in the braking system, particularly when the valve devices are all to be located together. It would, instead, be better to be able to make the devices smaller.

According to a first aspect of the present invention there is provided an electromagnetic valve device comprising:

a casing housing first ends of a plurality of electromagnetic valves, and having said electromagnetic valves disposed therein; an end yoke which is fitted to each of the second ends of said electromagnetic valves, said end yoke forming a part of a magnetic path; and clamping means coupling said end yoke and said casing, whereby said electromagnetic valves are held between said end yoke and said casing.

According to a second aspect of the present invention there is provided an electromagnetic valve device having a housing with an inlet and outlet, a valve body in the housing having a passage therethrough ending at the valve seat, and a electromagnetically movable valve rod associated with the valve seat to open and close the passage, the passage, when open, connecting the inlet to the outlet, and a flexible seal between the valve body and the housing, and forming a one-way valve permitting flow from the outlet to the inlet.

The overall size of the structure formed by disposing a multiplicity of electromagnetic valves together according to the first aspect can be significantly reduced. Also, the invention can provide with the second aspect a device in which liquid can return smoothly and no individual space for the check valve is necessary.

According to the first aspect of the present invention, since the structure is arranged such that the casing houses the first ends of the plurality of electromagnetic valves, the other ends of the electromagnetic valves are secured by a yoke, and the en-:.' yoke forms a part of a magnetic path, the electromagnetic valves may be closely disposed. As a result, the overall size of the electromagnetic valve device can be reduced. Furthermore, since the plurality of the electromagnetic valves can be tightly secured in the casing, the strength of the structure can be significantly improved.

According to the second aspect of the present invention, when the pressure of liquid in the outlet passage becomes higher than that in the inlet passage, the movable seal which partitions the two passages is opened so that liquid returns to the inlet passage. As a result, a small electromagnetic valve device can be provided, the electromagnetic valve device having no individual check valve but having the similar function as that performable by the check valve.

As a result, by combining the above-described first and second aspects of the present invention, the size of the electromagnetic valve of a series unit type can be reduced, the electromagnetic valve exhibiting an excellent liquid returning speed.

The invention will be better understood from the following description which is given by way of example with reference to the accompanying drawings in which:

Figs. 1 and 2 are views which illustrate a first embodiment of the present invention, where Fig. 1 is a cross-sectional view, and Fig. 2 is a plan view; Fig. 3 is a cross-sectional view which illustrates a second embodiment of the present invention.

Y A Fig. 1 and Fig. 2 show four individual electromagnetic valves 1 held together so as to form a unitlike structure.

A casing 2 is arranged to be rectangular having four recessed portions 2a formed to house first ends of the four electromagnetic valves 1. The casing 2 has 8 holes for bolts formed therein. First passages 15 leading from the recesses 2a to a brake master cylinder (not shown in the drawings) and second passages 14 leading to a brake cylinder (not shown in the drawings) are formed so that the electromagnetic valves 1 can be mounted in the recesses 2a.

on the other hand, passages la for a reservoir (not shown in the drawings) are provided at the other ends of the electromagnetic valves 1, these passages la being connected to the reservoir. An end yoke 3 fitted to the electromagnetic valves is formed such that the ends of the passages la for the reservoir can appear outside.

The end yoke 3 is in direct contact with the solenoids 12 which actuate the electromagnetic valves, so that the end yoke 3 forms a part of a magnetic path for said electromagnetic valves 1. Eight bolt holes 3a and four holes 3b for fitting the electromagnetic valves are formed in the end yoke 3.

Bolts 4 threadedly couple the casing to the yo-ke via corresponding holes 3a in the yoke and 2b in the casing.

As described above the structure is arranged in such a manner that the casing 2 is shaped to serve as a housing for first ends of the plurality of electromagnetic valves 1, these electromagnetic valves can be disposed close together and the other ends of the electromagnetic valves 1 are secured by the end yoke 3 which forms a part of a magnetic path so that the electromagnetic valves 1 are held by a clamping means 4 between the end yoke 3 and the casing 2. Therefore, the electromagnetic valves can be disposed closely, causing the overall size of the electromagnetic valve device to be significantly reduced. Furthermore, since the plurality of electromagnetic valves 1 can be simultaneously secured to the casing 2, the assembly of the electromagnetic valve device can be readily completed. Furthermore, since the casing 2 is integrally formed, the strength can be improved.

Fig. 3 shows a second embodiment of the invention being a device with cylindrical housing 10 having solenoids 12 in the outer periphery thereof. Those parts of the housing 10 adjacent to the solenoids 12 are arranged to be non-magnetic bodies 20a.

The housing 10 includes two sets of valves disposed axially in series, each set of valves consisting of a decay valve A of a normally-closed type and a holdvalve B of a normally-open type. The hold valve B is. structured in such a manner that a valve rod 13 movable with a plunger 13a which is arranged to be driven by the Z:1 k solenoids 12 can be brought into contact with a valve seat 11 having a passage lla therein. As a result, a passage between a first passage 15 (which can be regarded as the inlet passage) and a second passage 14 (the outlet passage) can be opened and closed.

An annular flexible seal 16 is fitted around the valve seat body 11, the flexible seal 16 having an outer periphery which is arranged to be in contact with the inner surface of the housing 10 so that the first passage 15 and the second passage 14 are partitioned. The flexible seal 16 has a skirt portion projecting to the first passage 15 so that it can serve as a one-way valve arranged in such a manner that the direction from the second passage 14 to the first passage 15 is arranged to be the forward direction.

The valve rod 13 is integrally secured to the plunger 13a, the valve rod 13 having two ends which are slidably supported by rod guides 13b and 13c in the axial direction. Also a passage is formed in the outer peripheries of the plunger 13a and rod guides 13b and 13c. A coil spring S is interposed between the plunger 13a and the rod guide 13c so that the valve rod 13 is actuated tc be moved away from the valve seat 11.

Now the operation of the electromagnetic valve 1 shown in Fig. 3 will be described.

The first passage 15 is connected to the brake master cylinder so that the pressure of the liquid in the passage is raised on the application of a force to a brake t -8pedal (not shown in the drawing). The liquid supplied from the first passage 15 is introduced into the second passage 14 via the passage 11a formed in the valve seat body 11 and the hold valve B which has been opened.

Then, when the anti-lock control device is operated (the detailed description about this is omitted), the valve rod 13 of the hold valve B is moved downward as viewed in this drawing so that the passaage 11a formed from the first passage 15 to the second passage 14 is closed.

When the driver releases the brake pedal, the pressure of the liquid in the second passaage 15 is rapidly reduced. At this time, the valve rod 13 of the hold valve B is arranged to be moved upward as viewed in the drawing so as to open the passage lla. As a result, liquid is returned from the second passage 14 to the first passage 15. Simultaneously, the movable seal 16 which partitions the second passage 14 from the first passage 15 is brought into an opened state so that the liquid in the second passage 14 is rapidly and by a large quantity returned to the first passage 15. As a result, the response property of the braking system can be improved and a preparation for the next operation is completed.

As described above, since the movable seal 16 also serves as a check valve, a relatively small electromagnetic valve device can be provided, the electromagnetic valve device having no individual check valve but having a similar function as that performable by a check valve.

-g- Although the description has been made about the structure of a sole electromagnetic valve with reference to Fig. 3, a multiplicity of series electromagnetic valves each having the movable seal 16 may be arranged to be a unit type structure as shown in Fig. 1.

Although the present invention is applied to a double-valve type electromagnetic valve in which the solenoid and the plunger are respectively vertically combined, the present invention can, of course, be applied to a single type electromagnetic valve in which only one solenoid and plunger are disposed.

Claims

-10CLAIMS

1. An electromagnetic valve device comprising:

2. A device according to claim 1 wherein the coupling means are a plurality of bolts connecting the end yoke and the casing.

3. An electromagnetic valve device having a housing with an inlet and outlet, a valve body in the housing having a passage therethrough ending at the valve seat, and a electromagnetically movable valve rod associated with the valve seat to open and close the passage, the passage, when open, connecting the inlet to the outlet, and a flexible seal between the valve body and the housing, and forming a one-way valve permitting flow from the outlet to the inlet.

4. An electromagnetic valve device according to claim 3 wherein the flexible seal is annular.

5. An electromagnetic valve device according to claim 3 or 4 wherein said electromagnetic valve device is -11used in a braking system for a vehicle, and said first passage is connected to a brake master cylinder, while said second passage is connected to a brake cylinder.

6. An electromagnetic valve according to claim 3, 4 or 5 wherein said valve rod is integrally secured to a plunger, said valve rod having two ends thereof which are axially slidably supported by a pair of rod guides.

7. An electromagnetic valve device according to claim 3, 4, 5 or 6 wherein said electromagnetic valve device is arranged to be of a double- valve type in which two sets of solenoids and plungers are, in series, disposed in the axial direction, the plungers having a by-pass passage formed in their peripheries leading to valve passages of both said valves and the fluid outlet port.

8. A valve device constructed and arranged substantially as hereinbefore described with reference to and as illustrated in Fig. 3 of the accompanying drawings.

9. A valve device constructed and arranged substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and 2 of the accompanying drawings.

10. A valve device according to claim 1 or 2 wherein the valves are valve devices according to any of claims 3-8.

Published 1990 at The Patent OLlce-StateHcuse ee. 71 High Helberr,.Lon-. onWC I R 4TP Further copies mkv be obtained froin The PalenOfficc Saies Branch. St MaT-; Cra.y. Orping-n Kent ER5 3FLE Printei techni=,.;es ltd St Mary Cray. Hent. Con 1 87