JPH0234461A - Auxiliary braking device for work - Google Patents

Abstract

PURPOSE:To prevent a solenoid valve from performing misoperation due to vibration or the like by actuating an operating switch to operate the solenoid valve and continuing its operation by a memory unit, in case of the captioned device suitable for a vehicle performing work in a parking condition. CONSTITUTION:In an air brake device 10 containing a work auxiliary braking device suitable for a vehicle of crane truck or the like, compressed air in brake reservoirs 16a, 16b is supplied to an air over hydraulic(AOH) booster through double check valves 20a, 20b when a dual brake valve 18 is operated. While, when a solenoid valve 22 is operated, compressed air from a main reservoir 14 is supplied to the AOH booster. Here the solenoid valve 22 is controlled by a control circuit 30, containing a memory unit, in a manner wherein the solenoid valve 22 is opened, when an operating switch 46 is operated, continuing the operation while closed by controlling a release switch 38.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a working auxiliary braking device used for a working vehicle, such as a mixer truck, a crane truck, etc., which performs work in a parked state.

(Prior Art) As an auxiliary braking device for work of this kind, for example, as shown in the publication of Utility Model Publication No. 62-30829, it is arranged between a pressure source and a brake device, and the brake device responds to an operation command. A solenoid valve that supplies pressure to the brake system side and releases pressure to the brake device side in response to a release command, and an activation switch that is operated by the driver and gives an activation command to the solenoid valve, and a release switch that gives a release command. Are known.

According to such a device, when the parking brake is applied to stop a vehicle or the like, working braking force can be obtained by the pressure supplied through the electromagnetic valve.

(Problems to be Solved by the Invention) However, in the conventional technology described above, when work begins on a vehicle or the like, there is a risk that the solenoid valve may malfunction due to severe vibrations caused by the work. In that case, pressure is exhausted due to malfunction, resulting in a decrease in braking force for work, resulting in a problem of insufficient braking force. In particular, if the solenoid valve is of a self-holding type using a permanent magnet, as shown in the above-mentioned publication, and the solenoid coil is energized only when switching the valve, the above-mentioned insufficient braking force may occur. The problem becomes even more obvious.

This invention was made in consideration of one or more points,
An object of the present invention is to provide an auxiliary braking device for work that can prevent malfunction of a solenoid valve.

(Summary of the Invention) In the present invention, a specific memory device is provided between the solenoid valve and both the actuation and release switches. The memory device is activated by actuation of the activation switch and released by actuation of the release switch, and is capable of continuing the operation of the solenoid valve.

As a result, in the present invention, the solenoid valve is operated by the actuation of the activation switch to apply the work auxiliary brake, and at the same time, the operation of the solenoid valve is continued by the memory device. On the other hand, when the release switch is operated, the memory device is released, the solenoid valve is also released, and the work auxiliary brake is released. That is, the memory device can ensure normal operation of the solenoid valve.

(Embodiment) FIG. 1 is a diagram schematically showing a part of an air brake device including an auxiliary braking device for work which is an embodiment of the present invention, and FIG. FIG. 3 is a control circuit diagram of the device shown in FIG.

The air brake device is generally designated by the reference numeral 1 in FIG.
Indicated by 0. This air brake group M10 includes a near compressor 12 that supplies compressed air, a main reservoir 14 that stores the compressed air sent from the near compressor 12, and two brake reservoirs 16a that are each supplied with compressed air from the main reservoir 14. 16b. The compressed air in each brake reservoir 16a, 16b is supplied to the brake pedal 18a of the dual brake valve 18.
When the button is depressed, the air can be supplied to a pair of air-over-hydraulic boosters (not shown) through a pair of double-check valves 20a and 20b in response to the input. Also.

A pair of double check valves 20a, 20b are connected to the output of a solenoid valve 22, as can be seen in FIG. Therefore, when the solenoid valve 22 is operated, compressed air supplied from the main reservoir 14 is supplied to the air-over-hydraulic booster through the pair of double check valves 20a, 20b.

A control circuit 30 for controlling the solenoid valve 22 and the like is provided for such air piping. This control circuit 30 is mainly organized in a control box 32.

The control box 32 has a large number of terminals, and each terminal is connected as follows. First, a power source 34, which is a vehicle battery, is connected to a terminal 32a. A pressure holding lamp 36 in series with a power source 34 is connected to terminal 32b, and a release switch 38 is connected to terminal 32c. Further, a starter switch 40 and a site brake switch 42 are connected in series to the power source 34, and a work preparation light 44 and an activation switch 46 are connected to terminals 32d and 32e+, respectively, in series with them and in parallel with each other. ing. Further, a buzzer 54 is connected in series to the power source 34, and the other end of the buzzer 54 is connected to the terminal 32h.

The ground part is connected to the terminal 32f, the pressure switch 48 provided on the solenoid valve 22 is connected to the terminal 32g, and the handbrake sensor 50 connected in series with the ground part is connected to the terminal 32i. Then, the wheel rotation detection device 52 connects the terminal 32 to the terminal 32Q.
The operating coil side of the electromagnetic valve 22 is connected to a terminal 32m, and the releasing coil side thereof is connected to a terminal 32n.

Here, the functions or structures of each device connected to the control box 32 are summarized as follows.

Pressure holding light 36: A lamp that lights up when the pressure switch 48 is closed, indicating that the auxiliary braking device has been activated.

Release switch 38: A switch that closes when pushed and automatically opens when the push is stopped, and is a switch that releases the function of the auxiliary braking device.

Starter switch 40 corresponds to a key switch for the engine, and is normally open when the vehicle is running or during work.

Handbrake switch 42: A switch that immediately detects and closes when a handbrake (not shown) is activated.

Work preparation light 44: A lamp that lights up when both the starter switch 40 and the handbrake switch 42 are closed, the handbrake is applied with a predetermined force or more, and the handbrake sensor 50 is closed. Indicates that it can be used.

Activation switch 46: A switch having the same structure as the release switch 38, and is a switch that is pushed in when it is desired to perform auxiliary braking for work.

Pressure switch 48... By switching the solenoid valve 22, the double check valves 20a, 2 are removed from the main reservoir 14.
This is a switch that closes when a predetermined pressure is supplied to the 0b side.

Buzzer 54...Sounds when a predetermined condition is met to issue an alarm.

Handbrake sensor 50: When the handbrake is applied, the operating force of the handbrake is a predetermined force (for example, 2
This is a detection switch that closes when the pressure reaches 5kgf).

Wheel rotation detection device 52...This is a device that detects the rotation of wheels, and includes a plurality of permanent magnets 62a attached to the rotating portion 60a of six wheels 60, which will be explained in more detail with reference to FIG. , 62b, 62C and the non-rotating part 6
A permanent magnet 62a has a pair of reed switches 64a and 64b attached to the permanent magnet 62a.

When the reed switches 62b and 62c are in the predetermined position relative to the reed switches 64a and 64b, the reed switches 64a and 5
4b is switched to close it.

In addition to the devices described above, a low pressure alarm switch 56 is provided. The low pressure alarm switch 56 is located between the buzzer 54 and the terminal 32h, and is connected to the main reservoir 1.
When the pressure inside 4 falls below a predetermined pressure, it closes and a buzzer 54 sounds regardless of the operation of the control box 32.

Now, the solenoid valve 22 is of the same type as that shown in the above-mentioned publication. To explain it simply, there is a single plunger, a pair of permanent magnets placed on both sides of the stroke of the plunger to hold the plunger in position, and the plunger is moved to the operating position by overcoming the attractive force of the permanent magnets. It has an actuating coil that energizes and a release coil that energizes to the release position. In FIG. 2, the actuation coil 22a of the solenoid valve 22 is connected to a terminal 32m, and the release coil 22b is connected to a terminal 32n.

When the actuation coil 22a is energized, the solenoid valve 22 is in the position A shown in the figure, communicating the main reservoir 14 and the double check valves 20a, 20b.On the other hand, when the release coil 22b is energized, the solenoid valve 22 is in the position A shown in the figure. Switch to position B, shut off the main reservoir 14 side, and double check valve 20a.

Exhaust the 20b side.

Next, the circuit configuration inside the control box 32 will be explained. A power supply circuit 70 is provided connected to the terminals 32a, 32b associated with the power supply 34. A diode 72 is inserted into the input side of the power supply circuit 70.
The input voltage VDD and output voltage vCC of 0 are respectively supplied to necessary parts of the circuit within the control box 32.

Inside the control box 32, at its center are a pair of flip-flops 74,76.

Regarding the lower flip-flop 74, the set terminal 748 is connected to the terminal 3 through the resistor R and the buffer 78.
2e, and is grounded via a capacitor C. In addition, the reset terminal 7 of the flip-flop 74
Similarly, 4R is connected to the terminal 32c via a resistor R and a buffer 80, and is also grounded via a capacitor C.

On the other hand, the output terminal 74Q of the flip-flop 74 is NP
It is connected to the base of the N-type transistor 82, and the 1-inverting terminal 74Q is connected to the base of the NPN-type transistor 84 and the respective reset terminals 100R and 102R of separately provided flip-flops 100 and 102.

The collector side of the transistor 82 is connected to the input voltage VDD and the base of the PNP transistor 86, and the emitter side is connected to the terminal 32i. Further, the transistor 86 has its emitter side connected to the input voltage VDD, and its collector side connected to the terminal 32m and a ground portion via a diode 88, respectively. On the other hand, the transistor 84
The collector side is connected to the input voltage VDD and the base of the PNP type transistor 90, and the emitter side is connected to another N
It is connected to the collector side of the PN type transistor 92. The emitter of the transistor 92 itself is grounded, the base is connected to the buffer 80 via a resistor R, and is branched to ground via another resistor R. Further, the collector side of the transistor 90 is connected to the terminal 32n and to the ground portion via a diode 93, respectively.

Now let's look at the upper flip-flop 76. A set terminal 76S of the flip-flop 76 is connected to a NOR gate 94, and the NOR gate 94 receives an input voltage VDD via a buffer 95, and a terminal 32g.
32b, respectively. Further, the reset terminal 76R of the flip-flop 76 is connected to the output side of the NOR gate 94 and the input side of the NOR gate 96 which receives a signal from the output terminal 74Q of the flip-flop 74. The input voltage VDD and signals from the terminals 32d and 32i are applied to the input side of the buffer 97. The output side of the buffer 97 is connected together with the output side of the buffer 95 to the input side of a NOR gate 98.

The output side of this NOR gate 98 and the inverting terminal 76ζ of the flip-flop 76 are connected to the input side of a NOR gate 99.

Furthermore, set terminals 100S and 1023 of flip-flops 100 and 102 are connected to terminal 32 and 32Q, respectively, via buffers 104 and 106, and output terminals 100Q and 102Q of these flip-flops are
It is connected to the input side of AND gate 108. AND
The output side of gate 108 is input to OR gate 110 along with the output side of NOR gate 99. The output side of this OR gate 110 is connected to the base of an NPN transistor 112. The transistor 112 has its collector side connected to the output voltage VDD, and its emitter side connected via a resistor R to the base of another NPN transistor 114 and to the ground. The collector side of the transistor 114 is connected to the terminal 3 through the resistor R.
2h, and the emitter side is grounded.

Incidentally, in FIG. 2, it goes without saying that R indicates resistance.

Next, regarding the operation by the control circuit 30 described above,
This will be explained mainly with reference to FIG.

When the vehicle is running normally, the starter switch 4
0 is closed. But other switches 42.38,46
, 48, and 50 are open, so the control box 3
There is no action in 2. In response to the previous auxiliary braking release command, the output terminal 74Q of the flip-flop 74 in the control box 32 is at the "L11 level," the inverting terminal 74Q is at the "HIT level," and the inverting terminal 76Φ of the flip-flop 76 is at the "HIT" level. “It has become a HIT level.

At this time, as the vehicle travels, the wheel rotation detection device 5
2, the closing signals of the reed switches 64a, 64b are alternately supplied to the terminals 32, 32K, and therefore the set terminals 100S, 102 of the flip-flops 100, 102.
A set signal is given to S. However, "H" is applied to each reset terminal 100R, 102R from the flip-flop 74.
Since the level input is received, the flip-flop 10
0°102 output terminals 100Q and 102Q are simultaneously “H”
Therefore, the output of the AND gate 108 is at the "L" level.
Since both NOR gates 8 and 50 are open, and the input from the buffer 97.95 is at the 11 HII level due to the input voltage VDD, the outputs of the NOR gates 98 and 94 are both at the "L" level. The inputs to the NOR gate 96 are the output of the NOR gate 94 and the output from the flip-flop 74, both of which are at the "IIL" level. Therefore, the output side of the NOR gate 96 is "H".
level, which is the terminal 76 of the flip-flop 76.
Join R. As a result, the inverting terminal 76ζ of the flip-flop 76 is at the "H" level, the inputs to the NOR gate 99 are "L" and uH, and the output is "L I
+ level. As a result, both inputs of the OR gate 110 are at "L" level, and its output is "L I+
level, making the transistor 112 non-conductive. Therefore, the buzzer 54 does not sound.

On the other hand, the output of the inverting terminal 74Q of the flip-flop 74 is II H1 level, and the output of the buffer 80 is "L'
'' level, the transistor 84 is conductive but the transistor 92 is non-conductive. Therefore, the transistor 90 is non-conductive, so that the release coil 22b is not energized and is in a demagnetized state. , the operation switch 46 is closed due to a malfunction, and the output from the output terminal 74Q of the flip-flop 74 temporarily becomes U.
Even if the Hn level is reached, the transistor 82 will not conduct unless the handbrake sensor 50 is closed. Therefore, while the vehicle is running, the operating coil 22a
is not energized, and auxiliary braking is not applied unexpectedly.

Thereafter, when the vehicle stops running and the handbrake is applied with a predetermined force or more, the handbrake switch 42 and sensor 50 are both closed and the work preparation light 44 is turned on.

In this state, the activation switch 46 is pressed for a predetermined period of time. Then, the output of the buffer 78 changes from the "L" level to the "H" level, the capacitor C starts charging, the potential rises to a predetermined value, and the set terminal 74S of the flip-flop 74
Give set input ′ to . In response, the flip-flop 74 sets the output terminal 74Q to "H" level.

The inverting terminal 74-5 is set to the "L" level. As a result,
Transistor 82 is conductive because handbrake sensor 50 is closed, transistor 86 is also conductive, and therefore actuating coil 22a is energized.

As a result, the solenoid valve 22 is switched, and the double check valve 20a is opened from the main reservoir 14 side.

Compressed air is supplied to the 20b side and auxiliary braking is applied.

When the pressure exceeds a predetermined value, the pressure switch 48 closes, but before that, the pressure switch 48 opens,
The handbrake sensor 50 is closed, and then both are closed. Both before and after the pressure switch 48 changes from open to closed, the buzzer 54 is not sounded as shown below. That is, flip-flop 7
When the output terminal 74Q of 4 is at the 11H" level, the input of the buffer 97 is at the "H" level, and the input of the buffer 95 is at the "H" level, the outputs of the NOR gates 98 and 94 remain unchanged.
The output of the flip-flop 74 remains at “L” level.
” only changes to “HIt level.” Therefore, the input to the set terminal 76S of the flip-flop 76 does not change, and the input to the reset terminal 76R changes from "uH" to "L".
Since the level changes, the input of NOR gate 99 does not change.

Furthermore, if the pressure switch 48 is closed in this state, NO.
The output of R gate 98 is 11 HIf level, the output of NOR gate 94 is 44 Hjl level, NOR gate 96
Since the output of ttL remains at the ttL" level, the input of the NOR gate 99 is 11L #j on the NOR gate 98 side.
to "H" level, and the flip-flop 76 side changes from "aH" to "L" level due to the set input, so its output does not change.

However, suppose that the activation switch 46 is pressed in such a state that the handbrake sensor 50 does not close because the handbrake is not applied sufficiently.

In that case, the output of the output terminal 74Q of the flip-flop 74 changes from "L" level to H level, and the pressure switch 48 changes to "L" level.
” to “H” level, the flip-flop 76
The reset input changes to the "L" level and the set input changes to the level "taH", and the inputs of the NOR gate 99 both become the "L" level, so that its output becomes the "H" level, causing the buzzer 54 to sound.

In addition to this operation, when the pressure in the main reservoir 14 falls below a predetermined pressure, the low pressure alarm switch 56 closes, so the buzzer 54 is activated regardless of whether the vehicle is running or not. It rings.

The auxiliary brake for work is applied as described above, but even if the vehicle starts to move due to a pressure leak or the like while the brake is being applied, the buzzer 54 also sounds. In such an emergency, intermittent signals are provided from the wheel rotation detection device 52 to the terminals 32, 32Q. These signals are sent to buffers 104, 10
6 to set terminals 100S and 102S of flip-flops 100 and 102 as set inputs.

At this time, since the reset input from the flip-flop 74 is at the "L17" level, the output terminal 100Q of each flip-flop 100, 102.

The output of 102Q is maintained at the "Hlj" level, and the output of the AND gate 108 is at the "uH" level, which causes the transistor 112 to conduct through the OR gate 110.

In response, the buzzer 54 sounds.

On the other hand, when the auxiliary braking is released, the operation is as follows. If you press the release switch and then stop operating it, the switch will automatically return. At this time, the output of the buffer 80 temporarily becomes 11 Hn level, the capacitor C is charged, and after charging, a reset input is given to the reset terminal 74R of the flip-flop 74. As a result, the output of the output terminal 74Q of the flip-flop 74 changes from the 11H" level to the ILL" level, and the output of the inverting terminal 74 changes from the "L" level to the "H" level. Therefore, the transistor 82 is cut off, energizing the activation coil 22a is terminated, and the transistors 84, 92.90 are turned on, and the release coil 22b is energized.

Then, the double check valves 20a and 20b are exhausted, the pressure switch 48 is also opened, and the normal handbrake is applied. Note that if only the handbrake is released without releasing the auxiliary braking, the buzzer 54 will sound due to switching of the handbrake sensor 50. In this respect, it is similar to the case described above.

Here, the effects of the embodiment described above are summarized as follows.

(1) Even when auxiliary braking is applied without fully applying the handbrake, the buzzer 54 can be sounded to issue a warning in response to the handbrake sensor 50 being in the open state. Conversely, if an attempt is made to release the handbrake while the auxiliary braking is applied, a similar warning can be issued to alert the driver and others to apply the brakes correctly.

(2) Even if the vehicle or the like starts moving for some reason while auxiliary braking is being performed, a warning can be issued in response to the signal from the wheel rotation detection device 52.

(3) When auxiliary braking is performed, the flip-flop 74
The output of the output terminal 74Q continues until the release switch 38 is operated, and the activation coil 22a continues to be excited.

This prevents the auxiliary braking from being released unexpectedly due to vibrations, resulting in high safety.

(4) Even if the first activation switch 46 or the like malfunctions while the vehicle is running, the emitter side of the transistor 82 that controls energization to the activation coil 22a is connected to the handbrake sensor 50.
Since it is grounded through the handbrake sensor 50
As long as is open, the actuating coil 22a will not be energized. This prevents auxiliary braking from being applied unexpectedly while the vehicle is running.

(5) Since the capacitor C is provided on the input side of the set terminal 74S and reset terminal 74R of the flip-flop 74, the influence of radio wave interference can be eliminated.

(6) Safety measures are taken for energizing the release coil 22b. In other words, the release coil 22b is energized only when the release switch 38 is operated so that the transistor 84 is enabled to conduct and the transistor 92 is made conductive at the same time.

(Effects of the Invention) According to the present invention, the solenoid valve can be operated by operating the operating switch, and the operation can be continued by the storage device. Therefore, the solenoid valve will not malfunction due to vibrations caused by work, and even if parts such as the plunger temporarily move due to sudden acceleration such as vibration acting on the solenoid valve, the solenoid valve will not malfunction. Since the system immediately returns to its normal operating state, a situation where the braking force is insufficient can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a schematic representation of a part of an air brake device including an auxiliary braking device for work, which is an embodiment of the present invention. FIG. 2 is a diagram showing an embodiment of a control circuit. 12... Near compressor, 22... Solenoid valve, 38
...Release switch, 46...Activation switch, 52.
...Wheel rotation detection device, 74...Flip-flop・Applicant: Japan Air Brake Co., Ltd. Agent Patent attorney: Toshio Hoshina

Claims (1)

[Claims] 1. A solenoid valve is placed between the pressure source and the brake device, and supplies pressure to the brake device side in response to an activation command, and releases pressure on the brake device side in response to a release command. In an auxiliary braking device for work having an activation switch that gives an activation command to a valve and a release switch that gives a release command to a valve, there is a storage device between the solenoid valve and both the switches, and this storage device stores information about the activation of the activation switch. It operates and is released by operating the release switch, and
An auxiliary braking device for work that can continue operating the solenoid valve by its operation.