JP3839113B2 - Vacuum brake booster - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum brake booster incorporating a solenoid.
[0002]
[Prior art]
A vacuum brake booster that assists the output with the vacuum pressure generated by the suction of the intake manifold of the engine and can adjust the output by the operation of the built-in solenoid is disclosed in, for example, JP 7-506785 A There is something that was done.
[0003]
[Problems to be solved by the invention]
Since the conventional vacuum brake booster uses vacuum pressure generated by suction by the intake manifold of the engine, it is naturally connected to the intake manifold of the engine, but vaporized gasoline enters from the intake manifold. If this happens, there is a possibility of ignition when a spark is generated due to damage to the built-in solenoid power supply system.To prevent this, there is a check valve between the intake manifold and the intake manifold. Will be provided.
However, when a failure such as a seal failure occurs in the check valve, the vaporized gasoline enters from the intake manifold as a result. Such a situation does not occur when the engine is turned on and sufficient suction pressure is generated in the intake manifold, because there is a flow from the vacuum brake booster side to the intake manifold side, but the engine is turned off and the intake manifold is This is particularly likely to occur when sufficient suction pressure is not generated.
Accordingly, an object of the present invention is to provide a check valve provided between the intake manifold and a malfunction such as a seal failure, and even if gasoline vaporized from the intake manifold may enter the check valve, It is an object of the present invention to provide a vacuum brake booster that can prevent a spark from flying due to damage to a power supply system circuit or the like.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the vacuum brake booster according to claim 1 of the present invention assists the output with the vacuum pressure generated by the suction by the intake manifold of the engine and adjusts the output by the operation of the built-in solenoid. A booster body capable of controlling power supply to the solenoid, and the control means determines whether the engine is on or off based on the power generated by the alternator or the engine speed. / and OFF determination unit, if the engine by the oN / OFF determination unit is determined to be in the oN state to allow the power supply to the solenoid, the power supply to the solenoid when the engine is determined to be in the OFF state And a solenoid prohibition judging means for prohibiting .
As a result, when the check valve provided between the intake manifold and the intake manifold has a malfunction such as a defective seal, vaporized gasoline may enter from the intake manifold. The control means prohibits the power supply to the solenoid when the ON / OFF determination means determines that the engine is in the OFF state, so that the power supply is caused by damage to the power supply system circuit to the built-in solenoid. There is no spark flying from the system circuit.
[0005]
According to a second aspect of the present invention, in addition to the first aspect, the control means operates only when the ON / OFF determination means determines that the engine is in the ON state. has a solenoid test functions, said solenoid test function is a failure of the solenoid characterized by the Turkey be detected in power supply to the solenoid.
As a result, the solenoid test function for detecting a failure of the solenoid by supplying power to the solenoid operates only when the engine is determined to be in the ON state by the ON / OFF determination means, and is therefore provided between the intake manifold and the intake manifold. The control means activates the solenoid test function when the engine is turned off. Therefore, a spark does not fly from the power supply system circuit due to damage to the power supply system circuit of the built-in solenoid.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a vacuum brake booster according to the present invention will be described below with reference to the drawings.
FIG. 1 shows a booster body 11, which is the same as that shown in Japanese Patent Publication No. 7-506785.
The casing 10 includes a front wall 10a and a rear wall 10b that are connected to the vehicle body by a tie rod 18, and includes a movable wall 16 that divides the inside into a constant pressure chamber 14 and a working pressure chamber 12 that are separated from each other. Yes. The constant pressure chamber 14 is always connected to an intake manifold (not shown) via a check valve.
[0007]
A control valve 20 is incorporated in the casing 10, and the control valve 20 includes a movable valve body 22 and a movable valve body 22 in the extending direction of the axis A (hereinafter referred to as the axial direction) with respect to the casing 10. Have. An annular first valve seat 24 is formed inside the valve body 22, and the first valve seat 24 has a channel 26 communicating with the working pressure chamber 12 and a channel 28 communicating with the constant pressure chamber 14. It is separated. An annular hole is formed in the valve body 22 inside the flow path 26 in the radial direction, and a sleeve-like valve closing member 30 is inserted into the hole so as to be movable in the axial direction. . A second valve seat 32 concentric with the first valve seat 24 is formed at the rear end of the valve closing member 30.
[0008]
The valve closing member 30 has a hole 34 extending in the radial direction on the front side spaced from the second valve seat 32, and the valve body 22 radially outside the hole 34 has a shaft 34. A wide hole 36 is formed in the direction. A valve spring 38 that presses the valve closing member 30 rearward is disposed in the annular hole of the valve body 22.
A valve body 22 is incorporated in the control valve 20 so as to surround the solenoid 40 in the radial direction of the valve closing member 30, so that the valve closing member 30 can move in the axial direction by excitation of the solenoid 40. ing.
[0009]
A plunger 42 is movably provided in a hole formed in the center of the valve body 22 and coaxial with the annular hole, and a rear end of the plunger 42 is connected to a rod-like actuating member 44. The front end extends to the concave portion formed on the end surface of the valve body 22 on the constant pressure chamber 14 side, and the plunger head 46 is held. The plunger head 46 transmits a normal mechanical force together with a reaction disk 48 embedded in the concave portion of the valve body 22 and an output member 50 disposed in front of the reaction disk 48.
[0010]
The ring groove formed in the circumferential surface of the plunger 42 is locked so that the stopper member 52 is engaged and axially moves together with the plunger 42. The stopper member 52 is related to the axial direction of the plunger 42. Is configured to move integrally with the plunger 42. This stopper member 52 extends outward through the gap 34 and the gap 36 formed in the valve closing member 30 and the valve body 22 in the radial direction, and is in a non-actuated stationary position (position shown in FIG. 1). Thus, the plunger 42 is positioned and regulated by coming into contact with the stopper 54 formed by the shoulder portion of the casing 10.
[0011]
A ring-shaped sealing member 56 is fixed to the plunger 42 in the region between the stopper member 52 and the actuating member 44, and the sealing member 56 is interposed between the valve closing member 30 and the peripheral surface of the plunger 42. Sealed. In other words, atmospheric pressure is always applied to the rear side of the sealing member 56, but this atmospheric air passes between the valve closing member 30 and the peripheral surface of the plunger 42, and further passes through the gap 34 and the gap 36. Thus, introduction into the working pressure chamber 12 is prevented.
[0012]
The actuating member 44 is normally held at a rest position (position shown in FIG. 1) by a rear return spring 58. In this rest position, the actuating member 44 is elastically deformed by the biasing force of the spring 62 disposed inside the valve body 22. A possible ring-shaped sealing member 60 abuts the first valve seat 24 and the second valve seat 32.
The movable wall 16 and the valve body 22 coupled to the movable wall 16 and moving in the axial direction together with the movable wall 16 are held at a rearward movement limit position by a return spring 64.
[0013]
In the non-operating state, the stopper member 52 comes into contact with the stopper 54, and the stationary position of the plunger 42 is thereby determined. The valve closing member 30 is brought into contact with the stopper member 52 by the urging force of the valve spring 38, whereby the stationary position of the valve closing member 30 is also determined. At that time, the second valve seat 32 abuts against the sealing member 60 with a slight residual force of the valve spring 38, and the sealing member 60 abuts against the first valve seat 24 simultaneously with the biasing force of the spring 62.
[0014]
Next, the operation of the booster body 11 will be described. For example, when the operation member 44 connected to the brake pedal is moved forward by the depression of the brake pedal, and the plunger 42 is moved forward by this, the plunger 42 moves the valve closing member 30 forward via the stopper member 52, whereby the second valve seat 32 is separated from the sealing member 60, and the air flowing into the valve body 22 from the rear of the booster body 11 flows. The fluid is introduced into the working pressure chamber 12 through the passage 26 and further through the gap 36. At this time, since the sealing member 60 is in contact with the first valve seat 24, the working pressure chamber 12 is completely connected to the constant pressure chamber 14 that is in communication with the intake manifold of the engine and is at a vacuum pressure. Therefore, a differential pressure is generated between the working pressure chamber 12 and the constant pressure chamber 14. Due to this differential pressure, the movable wall 16 moves forward together with the valve body 22 to assist the output of the output member 50.
[0015]
When the mechanical output described above is accelerated and amplified in response to an emergency brake operation, power is supplied to the solenoid 40 from the controller (control means) 80 shown in FIG. 2 via a power supply system circuit (not shown). . Then, the solenoid 40 is excited, and thereby the solenoid 40 pulls the valve closing member 30 away from the stopper member 52 and pulls forward, whereby the flow path cross-sectional area between the second valve seat 32 and the sealing member 60 is increased. It spreads and more air enters the working pressure chamber 12 at a high speed, so that a large differential pressure is generated between the working pressure chamber 12 and the constant pressure chamber 14 at a high speed. Due to this differential pressure, the movable wall 16 moves forward together with the valve body 22 at a higher speed to assist the output of the output member 50.
[0016]
In addition, the operation member 44 connected to the brake pedal supplies power to the solenoid 40 from the controller 80 via a power supply system circuit (not shown) in a state in which the brake pedal is not depressed and is not moved forward. In the same manner as described above, a differential pressure is generated between the working pressure chamber 12 and the constant pressure chamber 14, and the movable wall 16 moves forward together with the valve body 22 by this differential pressure to cause the output member 50 to output. Can do. Therefore, in traction control and automatic braking, braking force can be generated even when the brake pedal is not depressed.
[0017]
When the power supply to the solenoid 40 is stopped, the valve closing member 30 is pushed back again by the valve spring 38, so that the valve closing member 30 abuts against the stopper member 52. When the introduction of the mechanical force via the actuating member 44 is stopped, the plunger 42 immediately returns to the stationary position together with the valve closing member 30 by the biasing force of the return spring 58. The movable wall 16 and the valve body 22 are not involved in this return operation when a differential pressure exists between the working pressure chamber 12 and the constant pressure chamber 14, and this differential pressure is caused by the valve closing member 30. Decrease by temporarily pushing the sealing member 60 rearward and moving the sealing member 60 away from the first valve seat 24.
[0018]
In this embodiment, the controller 80 that controls the power supply to the solenoid 40 built in the booster body 11 via a power supply system circuit (not shown) includes a stroke sensor 82 that detects the depression stroke of the brake pedal, A brake switch 83 for detecting whether or not the brake pedal is depressed, a wheel speed sensor 84 for detecting the speed of each wheel, a solenoid monitor 85 for determining the state of the solenoid 40, and an alternator driven by the rotation of the engine Is connected to an alternator monitor 86 for detecting the generated power.
[0019]
The controller 80 includes a solenoid operation request determination circuit 88 connected to the stroke sensor 82, the brake switch 83, and the wheel speed sensor 84, a solenoid failure detection circuit 89 connected to the solenoid monitor 85, and the solenoid operation request determination circuit 88. The OR circuit 90 to which the output and the output of the solenoid failure detection circuit 89 are input, the engine ON / OFF determination circuit (ON / OFF determination means) 92 connected to the alternator monitor 86, and the engine ON / OFF determination circuit 92 A connected solenoid prohibition determination circuit (solenoid prohibition determination means) 93, an AND circuit 94 to which the output of the OR circuit 90 and the output of the solenoid prohibition determination circuit 93 are input, and a solenoid drive circuit connected to the AND circuit 94 95.
[0020]
As shown in FIG. 3, the controller 80 starts control when an ignition key (not shown) is turned ON, and inputs a detection signal from the stroke sensor 82 to the solenoid operation request determination circuit 88 (step A1). The detection signal from 83 is input to the solenoid operation request determination circuit 88 (step A2), and further, the detection signal from the wheel speed sensor 84 is input to the solenoid operation request determination circuit 88 (step A3). Then, from these detection signals, the solenoid operation request determination circuit 88 performs a control calculation to determine whether or not an emergency brake operation state is present (step A4). Here, for example, when the brake switch 83 is turned ON, the stroke speed from the stroke sensor 82 exceeds a predetermined value, and the wheel speed from the wheel speed sensor 84 exceeds a predetermined value. The solenoid operation request determination circuit 88 determines that it is in an emergency brake operation state and outputs a solenoid operation request, and otherwise determines that there is no emergency brake operation state and prohibits the output of the solenoid operation request. .
[0021]
Next, an input is made from the solenoid monitor 85 to the solenoid failure detection circuit 89 (step A5), and the solenoid failure detection circuit 89 determines whether or not the solenoid 40 is in a failure state (step A6). Here, in the solenoid monitor 85, for example, it is determined whether or not the solenoid 40 is in a failure state at the time of the previous power supply to the solenoid 40 (step A11), and this data is stored. Input to the circuit 89.
The power supply to the solenoid 40 affects the braking force of the solenoid 40 when the solenoid 40 is driven to respond to an emergency brake operation and when the solenoid 40 is not supplied with power for a predetermined time. This is performed in two cases, when a solenoid test is performed in which power is not supplied for a short time to determine the failure state. Further, the solenoid drive circuit 95 determines whether or not the solenoid 40 is in a failure state based on whether or not electrical characteristics such as a current value when power is supplied to the solenoid 40 are within an allowable range.
[0022]
In Step A7, when it is determined by the solenoid failure detection circuit 89 that there is no failure in the solenoid 40, the engine ON / OFF determination circuit 92 performs engine ON / OFF determination (Step A8). Here, as shown in the flowchart of FIG. 4, when the detection signal of the power generation of the alternator at that time is input from the alternator monitor 86 (step B1), this determination is performed according to a predetermined value. It is determined whether or not it is “H” (step B2). If the generated power exceeds a predetermined value, the counter N = N + 1 (step B3), where N is predetermined. It is determined whether or not the predetermined value T _ON has been exceeded (step B4), and when N exceeds a predetermined value T _ON , the time required for the engine to be sufficiently evacuated from at least the working pressure chamber 12 It is determined that it is in a state after rotating (for example, 3 seconds), and is determined to be in an ON state (step B5).
[0023]
On the other hand, if it is determined in step B2 that the generated power does not exceed a predetermined value, N = 0 is set (step B6), and it is determined that the engine is in the OFF state (step B7). In Step B4, if N does not exceed a predetermined value T _ON , it cannot be determined that the engine is in a state after being rotated for at least a time during which vacuuming is sufficiently performed from the working pressure chamber 12, It is determined that the engine is in an OFF state (step B7).
[0024]
When the engine ON / OFF determination circuit 92 determines that the engine is on (step A9), the solenoid prohibition determination circuit 93 outputs a solenoid drive approval, and the solenoid operation request determination circuit 88 outputs a solenoid operation request. In step A10, if a solenoid operation request is output, a drive signal is output from the solenoid drive circuit 95 to the solenoid 40, that is, power is supplied (step A11).
[0025]
On the other hand, if it is determined in step A10 that the solenoid operation request has not been output, whether or not the solenoid test request that is output in a state where the power supply to the solenoid 40 is not performed for a predetermined time is output. Determine (step A14). If a solenoid test request is output, a drive signal for testing is output from the solenoid drive circuit 95 to the solenoid 40, that is, power is supplied (step A11). On the other hand, when the solenoid test request is not output, the output of the drive signal from the solenoid drive circuit 95 to the solenoid 40 is prohibited (step A12).
In Step A7, when it is determined by the solenoid failure detection circuit 89 that the solenoid 40 has a failure, a warning lamp provided at a position where the driver can see is turned on (Step A13), and the solenoid drive circuit 95 is turned on. The drive signal is prohibited from being output to the solenoid 40 (step A12).
Furthermore, when the engine ON / OFF determination circuit 92 determines that the engine is in the OFF state in step A9, output of the drive signal from the solenoid drive circuit 95 to the solenoid 40 is prohibited (step A12).
[0026]
According to the vacuum brake booster described above, when a check valve provided between the intake manifold and the intake manifold has a failure such as a defective seal, vaporized gasoline may enter from the intake manifold. When the engine is turned off, the controller 80 prohibits power supply to the solenoid 40 when the engine ON / OFF determination circuit 92 determines that the engine is in the OFF state. This prevents a spark from flying from the power supply system circuit due to the damage of the power supply system circuit, and thus prevents ignition.
[0027]
In addition, the solenoid test function for detecting a failure of the solenoid 40 by supplying power to the solenoid 40 operates only when the engine ON / OFF determination circuit 92 determines that the engine is in the ON state. When the check valve provided between them has a failure such as a seal failure, the vaporized gasoline may enter from the intake manifold. When the engine is turned off, the controller 80 performs a solenoid test. The function is not actuated, so that it is possible to prevent a spark from flying from the power supply system circuit due to the damage of the power supply system circuit to the built-in solenoid 40 and the like to prevent ignition.
Note that the engine ON / OFF determination can be determined not only based on the power generated by the alternator, but also to be determined to be in the ON state at a predetermined rotation or more by the rotation detected by the tachometer.
[0028]
【The invention's effect】
As described above in detail, according to the vacuum brake booster of the first aspect of the present invention, when a failure such as a seal failure occurs in a check valve provided between the intake manifold and the intake manifold, In a state where the vaporized gasoline may enter or the engine is turned off, the control means prohibits power supply to the solenoid when the ON / OFF determination means determines that the engine is in the OFF state. Therefore, a spark does not fly from the power supply system circuit due to damage to the power supply system circuit to the built-in solenoid, and therefore it is possible to prevent ignition.
[0029]
According to the vacuum brake booster of the second aspect of the present invention, the solenoid test function for detecting a solenoid failure by supplying power to the solenoid is performed when the ON / OFF determination means determines that the engine is in the ON state. Therefore, if the check valve provided between the intake manifold and the intake manifold has a malfunction such as a seal failure, the gasoline that has vaporized may enter from the intake manifold. In the state, the control means does not activate the solenoid test function, and therefore the spark does not fly from the power supply system circuit due to the damage of the power supply system circuit to the built-in solenoid, etc. Can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of a booster body according to an embodiment of a vacuum brake booster of the present invention.
FIG. 2 is a block diagram showing a control system of an embodiment of a vacuum brake booster of the present invention.
FIG. 3 is a flowchart showing the control contents of an embodiment of a vacuum brake booster of the present invention.
FIG. 4 is a flowchart showing the control contents of engine ON / OFF determination according to one embodiment of the vacuum brake booster of the present invention.
[Explanation of symbols]
40 Solenoid 80 Controller (control means)
92 Engine ON / OFF determination circuit (ON / OFF determination means)

Claims (2)

A vacuum type having a booster body capable of assisting output by vacuum pressure generated by suction by an intake manifold of the engine and capable of adjusting output by operation of a built-in solenoid, and control means for controlling power supply to the solenoid In the brake booster,
The control means includes ON / OFF determination means for determining the ON / OFF state of the engine based on the generated power of the alternator or the engine speed ,
Solenoid prohibition determination means for enabling power supply to the solenoid when the ON / OFF determination means determines that the engine is in the ON state and prohibiting power supply to the solenoid when it is determined that the engine is in the OFF state. And a vacuum brake booster. Wherein said control means includes a solenoid test function to operate only when it is determined that the engine is in the ON state by the ON / OFF determination unit, the solenoid test function failure of the solenoid at the feed to the solenoid vacuum brake booster according to claim 1, wherein the detection to Turkey.

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