JP3571150B2 - solenoid valve - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solenoid valve which is preferably applied to an anti-lock brake device for controlling a brake fluid pressure of a vehicle.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an anti-lock brake device that controls brake fluid pressure of a vehicle in order to prevent locking of wheels during braking of the vehicle has been known. As shown in FIG. 3, for example, the anti-lock brake device includes a master cylinder 2 that generates a brake hydraulic pressure in accordance with a pedaling force applied to a brake petal 1, and a main cylinder 2 that guides the hydraulic pressure of the master cylinder 2 to a wheel cylinder 3. A passage 4, a normally-open type pressure-intensifying solenoid valve 5 provided in the middle of the main passage 4, a return passage 7 for communicating the wheel cylinder 3 with the reservoir 6, and a return passage 7 provided in the middle of the return passage 7; And a normally closed pressure reducing solenoid valve 8. In the figure, reference numeral 9 denotes a pump mechanism for returning the brake fluid in the reservoir 6 to the master cylinder 2.
[0003]
If the wheels are likely to lock during the braking operation by depressing the brake petal 1, the pressure-intensifying electromagnetic valve 5 is closed, the pressure-reducing electromagnetic valve 8 is opened, and the hydraulic pressure in the wheel cylinder 3 is returned to the return passage. The fluid is caused to flow into the reservoir 6 via the control valve 7 so as to reduce the hydraulic pressure in the wheel cylinder 3 to avoid locking the wheels.
[0004]
More specifically, in this antilock control, pressure reduction, holding, and pressure increase of the brake fluid pressure are repeated in order to obtain an optimal braking state. Therefore, the opening and closing operations of the respective solenoid valves 5 and 8 are repeated. At this time, from the state where both the pressure-increasing-side electromagnetic valve 5 and the pressure-reducing-side electromagnetic valve 8 are closed (the holding state), the moment when the pressure-increasing-side electromagnetic valve 5 is opened to increase the pressure, it is higher than the pressure-increasing-side electromagnetic valve 5 The high-pressure main passage 4 on the upstream side (master cylinder 2 side) communicates with the low-pressure main passage 4 on the downstream side (wheel cylinder side) of the pressure-increase solenoid valve 5. For this reason, a sharp pressure drop occurs in the main passage 4 upstream (the master cylinder 2 side) of the pressure-intensifying solenoid valve 5, and in the main passage 4 downstream (the wheel cylinder side) of the pressure-intensifying solenoid valve 5. Surge pressure will be generated. Thereby, at the time of antilock control, there is a possibility that abnormal noise or vibration may occur due to sudden pressure fluctuation in the hydraulic circuit.
[0005]
In order to cope with this, for example, Japanese Unexamined Patent Publication No. Hei 4-266676 discloses that a check valve having a throttle passage such as a cup seal is attached to a plunger of an electromagnetic valve to prevent a sudden opening / closing operation. Solenoid valves have been proposed.
[0006]
[Problems to be solved by the invention]
However, in the conventional example, since the check valve is attached, an increase in the number of parts and a high processing accuracy are required, which may lead to an increase in manufacturing cost.
[0007]
The present invention has been devised in view of such a conventional situation, and has as its object to provide an electromagnetic valve capable of suppressing a rapid pressure fluctuation without increasing the number of parts.
[0008]
[Means for Solving the Problems]
Therefore, the present invention provides a passage forming body in which a first passage communicating with a master cylinder and a second passage communicating with a wheel cylinder are formed , a valve body main body attached to the passage forming body and having a recess at a lower end side. A valve seat attached to the lower end of the valve body for closing the recess, a communication passage formed in the valve seat and communicating the first passage with the expansion chamber, and a slide formed in the valve body. wherein while being slidably housed in the axial direction into the hole, a plunger is in contact with the armature is attracted by the suction force one end is generated when energizing the electromagnetic coil disposed on the outside, with the expansion chamber and a orifice for communicating the second passage and the expansion chamber between the second passage, opening and closing the communication passage at the other end of the plunger by axial movement of the plunger, before Communicating the first passage and the second passage, it is characterized in carrying out the cutoff.
[0011]
Here, the volume of the expansion chamber can be arbitrarily set in order to most effectively reduce the pressure fluctuation of the liquid. Similarly, the most preferable area and number of the orifices are also arbitrarily selected.
[0012]
According to this configuration, the pressure fluctuation of the liquid flowing between the first passage and the second passage is reduced by the expansion chamber and the orifice.
[0013]
Therefore, it is possible to obtain an electromagnetic valve capable of suppressing a sudden pressure fluctuation during operation without increasing the number of parts, and to advantageously prevent abnormal noise and vibration due to pressure fluctuation in the circuit. be able to.
[0014]
In addition, since a cup seal is not used to reduce pressure fluctuations in the hydraulic circuit, there is no deterioration in performance due to wear or performance deterioration at cryogenic temperatures. A valve is obtained.
[0015]
The front Symbol expansion chamber from is formed in the valve body, never particularly solenoid valve becomes large.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings as an embodiment applied to a pressure-increasing solenoid valve of an anti-lock brake device.
[0017]
FIG. 1 is a sectional view of a solenoid valve according to an embodiment of the present invention. In the figure, 11 is a passage forming body, 12 is a first passage formed in the passage forming body 11, and 13 is a second passage. The first passage 12 communicates with a master cylinder (not shown), and the second passage 13 communicates with a wheel cylinder (not shown).
[0018]
Reference numeral 14 denotes an electromagnetic valve, and a valve body 15 of the electromagnetic valve 14 is attached to the passage forming body 11. The valve body 15 includes a valve body main body 17 having a recess 16 at the lower end side, and a valve seat 18 attached to the lower end side of the valve body main body 17 to close the recess 16. An expansion chamber 19 is formed by the recess 16. The expansion chamber 19 communicates with the second passage 13 through orifices 20 formed at two symmetric positions of the body of the valve body main body 17. The valve seat 18 has a communication passage 21 that connects the expansion chamber 19 and the first passage 12.
[0019]
A slide hole 22 for a plunger, which will be described later, is formed in the valve body main body 17, and the end of the plunger is seated on an end of the communication passage 21 formed in the valve seat 18 on the side of the expansion chamber 19. A valve seat 21a is formed.
[0020]
Reference numeral 23 denotes a cylindrical cylinder mounted on the upper end of the valve body 15. The cylinder 23 is made of a non-magnetic material, and the upper end of the cylinder 23 is sealed by a cap 24. An armature 25 that operates by controlling the power supply to an electromagnetic coil, which will be described later, is slidably inserted into the cylinder 23.
[0021]
A plunger 26 operably connected to the armature 25 is slidably inserted into a sliding hole 22 formed in the valve body 17. The plunger 26 includes a large-diameter portion 27 on the side of the armature 25 and a small-diameter portion 29 connected to the large-diameter portion 27 with a stepped portion 28. The communication passage 21 can be opened and closed on the side of the expansion chamber 19 by coming into contact with and separating from the valve seat 21 a of the valve 18. A compression spring 31 is provided between the step 28 of the plunger 26 and the spring seat 30 of the valve seat 18, and the plunger 26 is urged toward the armature 25 by the compression spring 31, so that the plunger 26 is in a normal state. The communication passage 21 is open.
[0022]
Reference numeral 33 denotes an electromagnetic coil wound around a bobbin 34, and the electromagnetic coil 33 is arranged on the outer peripheral side of the cylinder 23. The electromagnetic coil 33 is connected to a control device (not shown) via a harness 35.
[0023]
Reference numeral 36 denotes a cover that covers the outer periphery and the lower end of the electromagnetic coil 33, and 37 denotes a retainer that covers the upper side of the electromagnetic coil 33. 38 is a filter attached to the end of the communication passage 21 of the valve seat 18 facing the first passage 12, and 39 is an annular member provided on the outer periphery of the body of the valve body 15 facing the second passage 13. Filters the liquid flowing into the expansion chamber 19 from the first passage 12 through the communication path 21 and the liquid flowing from the expansion chamber 19 to the second passage 13. Reference numeral 40 denotes a seal ring, and reference numeral 41 denotes a cup seal, which controls liquid-tight sealing with the passage forming body 11 to which the electromagnetic valve 14 is attached.
[0024]
In such a configuration, the solenoid valve 14 is attached to the passage forming body 11, the communication passage 21 communicates with the first passage 12 via the filter 38, and the expansion chamber 19 communicates with the second passage via the orifice 20 and the filter 39. 13. Further, in a normal state, the plunger 26 is urged toward the armature 25 by the spring force of the compression spring 31 to open the communication passage 21 as shown in FIG. It is possible to guide the hydraulic pressure of the master cylinder guided to the wheel cylinder via the expansion chamber 19 and the second passage 13.
[0025]
When the hydraulic pressure of the wheel cylinder increases during the braking operation and there is a possibility that the wheels are locked, anti-lock control is started, the electromagnetic coil 33 is excited by a signal from a control device (not shown), and the armature 25 is controlled. Move down from the position shown in 1. As a result, the plunger 26 moves downward against the spring force of the compression spring 31 and sits on the valve seat 21a of the valve seat 18 to cut off the communication between the first passage 12 and the second passage 13. At the same time, a pressure reducing solenoid valve (not shown) opens the return passage. As a result, the hydraulic pressure in the wheel cylinder is controlled to be reduced, and locking of the wheels is avoided.
[0026]
During the antilock control, if there is a possibility that the pressure of the wheel cylinder will be excessively reduced, the excitation of the electromagnetic coil 33 is released by a signal from a control device (not shown). As a result, the armature 25 and the plunger 26 are pushed upward again by the spring force of the compression spring 31, and the plunger 26 is separated from the valve seat 21a of the valve seat 18, and the communication between the first passage 12 and the second passage 13 is established. To resume. As a result, excessive decompression of the wheel cylinder is avoided.
[0027]
At this time, the high-pressure hydraulic fluid on the master cylinder side led from the first passage 12 once flows into the expansion chamber 19 having a large volume, and is then led to the wheel cylinder side via the orifice 20 having a small opening area. become. As a result, the speed of the pressure increase of the wheel cylinder is reduced, and the pressure is gradually increased. As a result, rapid pressure fluctuations in the hydraulic circuit are avoided. That is, as shown by the solid line in FIG. 2, when the plunger 26 strokes from the point A at a predetermined pressure to increase the pressure, the hunting operation is suppressed to a small extent and the point B is reached quickly. Therefore, the pressure fluctuation is smaller than in the conventional example shown by the broken line. As a result of the pressure fluctuation being suppressed to a small value, the pressure is converged to a predetermined pressure in a short time.
[0028]
Thereafter, in the antilock control, the solenoid valve 14 repeats the valve opening operation and the valve closing operation in order to obtain a predetermined braking pressure on the wheel cylinder.
[0029]
Therefore, when the solenoid valve 14 is operated, abrupt pressure fluctuations do not occur in the hydraulic circuit, and abnormal noise and vibration caused by the pressure fluctuations in the hydraulic circuit can be advantageously prevented. .
[0030]
In addition, since a cup seal is not used to reduce pressure fluctuations in the hydraulic circuit, there is no deterioration in performance due to wear or performance deterioration at cryogenic temperatures. A valve is obtained.
[0031]
Further, since the expansion chamber is formed in the valve body, the size of the special solenoid valve does not increase.
[0032]
Although the embodiments have been described with reference to the drawings, the specific configuration is not limited to the embodiments and can be changed without departing from the gist of the invention. For example, although the embodiment in which the orifice 20 communicating the second passage 13 and the expansion chamber 19 is formed at two symmetrical positions on the outer periphery of the body of the valve body main body 17 has been described, one or three or more may be provided. . Further, the present invention can be applied to a normally closed solenoid valve.
[0033]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to obtain an electromagnetic valve capable of suppressing a rapid pressure fluctuation during operation without increasing the number of parts. Therefore, generation of abnormal noise or vibration due to pressure fluctuation in the circuit can be advantageously prevented, and a very great effect can be obtained in practical use.
[Brief description of the drawings]
FIG. 1 is a sectional view of a solenoid valve according to an embodiment of the present invention.
FIG. 2 is a view for explaining energization of a solenoid valve and a change in hydraulic pressure in a hydraulic circuit accompanying the energization of the solenoid valve.
FIG. 3 is an explanatory diagram showing an overall configuration of an anti-lock brake device.
[Explanation of symbols]
Reference Signs List 11 passage forming body 12 first passage 13 second passage 14 solenoid valve 15 valve body 19 expansion chamber 20 orifice 21 communication passage 33 electromagnetic coil

Claims (1)

A passage forming body in which a first passage communicating with the master cylinder and a second passage communicating with the wheel cylinder are formed;
Attached to the passage forming body, a valve main body having a recess at the lower end,
A valve seat attached to a lower end side of the valve body main body to close the recess;
A communication passage formed in the valve seat and communicating the first passage with the expansion chamber ;
A sliding hole formed in the valve body is slidably received in the axial direction, and one end of the valve body is in contact with an armature that is sucked by a suction force generated when an electromagnetic coil disposed outside is energized. and the plunger was,
An orifice communicating between the expansion chamber and the second passage between the expansion chamber and the second passage;
An electromagnetic valve , wherein the communication passage is opened and closed at the other end of the plunger by moving the plunger in the axial direction, and the first passage and the second passage are communicated and blocked .

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