JP2006264417A - Hydraulic brake device of industrial vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic brake device which feeds discharged oil from a hydraulic pump for a brake to a working machine in an industrial vehicle having the working machine, applies the brake with the pressurized oil of an accumulator to brake the vehicle when the working machine is stopped, and the cargo handling speed is increased, and an engine is miniaturized. <P>SOLUTION: The industrial vehicle has a brake device to brake the vehicle by receiving discharged oil from a hydraulic pump for the brake through a brake operation valve, and a working device to operate the working machine by receiving discharged oil from a hydraulic pump for the work through a work operation valve. The brake device has the work operation valve or a solenoid valve connected to a tank between the hydraulic pump for the brake and the brake operation valve. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic brake device for an industrial vehicle, and more particularly to a hydraulic brake device for an industrial vehicle having a working device driven by hydraulic pressure and a brake device braked by hydraulic pressure.

  Conventionally, in an industrial vehicle such as a forklift, as shown in FIG. 15, two hydraulic pumps 83, 85 are driven by an engine 81, and the discharge oil of one working machine hydraulic pump 83 is switched by a work operation valve 87. It is sent to the working cylinder 89 and expanded and contracted, and a working machine such as a fork is operated to carry out cargo handling. Further, the other brake hydraulic pump 85 is connected to the wheel cylinder 93 of the brake device via the brake operation valve 91, and pressure oil is supplied by operating the brake petal 95 attached to the brake operation valve 91. The vehicle is braked by extending the wheel cylinder 93 with the pressure oil.

  In the above, for example, in a forklift of an automatic vehicle, when the vehicle is stopped and cargo handling is performed, the rotational speed of the engine 81 is increased and the discharge amount of the hydraulic pump 83 for the work machine is increased and sent to the work cylinder 89 to quickly A work machine such as a fork is operated. At this time, as the rotational speed of the engine 81 increases, the driving force due to the creep phenomenon also increases, but the operator strongly presses the brake petal 85 to increase the braking force and keeps stepping on it to prohibit driving. The vehicle is stopped and the cargo handling operation is performed.

Further, in normal braking of a vehicle, pressure oil is generated using a master cylinder, and the pressure oil is supplied to the wheel cylinder for braking. In recent years, an electric control brake system (brake-by-wire) has been actively developed along with electronic control of vehicles, and Patent Document 1 has been proposed as an example of the electric control brake.
According to Patent Document 1, when the brake petal is stepped on, the switching valve is excited by receiving a signal from the brake sensor, the master cylinder and the wheel brake are shut off, and the output port of the servo valve and the wheel brake are communicated. Subsequently, the linear solenoid of the servo valve is energized with an electric quantity corresponding to the output signal from the brake sensor, and the brake can be operated by supplying the hydraulic pressure from the hydraulic supply source to the wheel brake via the servo valve. .
JP 7-317941 A

By the way, in the industrial vehicle such as the forklift shown in FIG. 15 described above, it is necessary to keep stepping on the brake petal in order to prohibit the travel due to the creep phenomenon after the vehicle is stopped by the brake operation at the time of cargo handling, which increases the burden on the operator. ing. Further, if the engine rotation speed is increased in order to increase the speed of cargo handling, the traveling force due to the creep increases, so that it is necessary to increase the brake braking pressure, the load applied to the engine increases, and engine stall tends to occur. In order to prevent engine stall, it is necessary to increase the minimum rotational speed of the engine or to mount an engine with a large output torque, which causes a new problem of reducing fuel consumption.
Also in Patent Document 1, as described above, after the vehicle stops, it is necessary to keep stepping on the brake petal in order to prohibit traveling due to the creep phenomenon, which increases the burden on the operator.

Further, in the industrial vehicle such as the forklift described above, in order to quickly operate the work machine such as a fork, the engine rotation speed or the pump discharge volume (cc / rev) is increased to increase the discharge amount of the work machine hydraulic pump. There is a need to.
Increasing the rotational speed of the engine causes a problem that the running force increases due to the creep phenomenon as described above, and if the discharge volume (cc / rev) of the pump is increased, the load on the engine is increased. In order to prevent engine stalls, it is necessary to mount an engine with a large output torque, which causes a problem of worsening fuel consumption.

  The present invention has been made paying attention to the above-mentioned problems, and relates to a hydraulic brake device for an industrial vehicle. In particular, in an industrial vehicle having a work machine, the discharge oil of a brake hydraulic pump is supplied to the work machine. An object of the present invention is to provide a hydraulic brake device that brakes a vehicle by applying pressure by accumulator pressure oil when stopped, thereby speeding up cargo handling and reducing the size of the engine.

  To achieve the above object, according to a first aspect of the present invention, there is provided a brake device that brakes a vehicle by receiving discharge oil of a brake hydraulic pump from a brake operation valve, and receiving discharge oil of a work hydraulic pump from a work operation valve. In a hydraulic brake device for an industrial vehicle having a work device that operates a work machine, a work operation valve or a solenoid valve connected to a tank is disposed between the brake hydraulic pump and the brake operation valve. It is characterized by.

  The second invention includes an accumulator that supplies pressure oil to the brake device, a pressure sensor that detects the hydraulic pressure of the accumulator, a speed sensor that detects the vehicle speed, and a brake operation sensor that detects that the brake operation valve has been operated. Control means for outputting a switching signal to the solenoid valve when the brake operation valve is operated from the brake operation sensor, the vehicle speed from the speed sensor is zero, and the pressure sensor receives a signal indicating that the hydraulic pressure of the accumulator exceeds a predetermined pressure It is characterized by consisting of.

  The third invention includes an auxiliary brake of a brake device that operates at least when the vehicle speed is zero, a speed sensor that detects a vehicle speed, a brake operation sensor that detects that a brake operation valve is operated, and a brake operation sensor It is characterized by comprising a control means for outputting a switching signal to the electromagnetic valve and an operation signal to the auxiliary brake when the brake operation valve is operated and a vehicle speed signal from the speed sensor is received.

  According to a fourth aspect of the present invention, there is provided an accumulator for supplying pressure oil to a brake device or an auxiliary brake, a pressure sensor for detecting an oil pressure of the accumulator, a speed sensor for detecting a vehicle speed, and a brake for detecting that a brake operation valve has been operated. Operation sensor, brake solenoid valve for supplying accumulator pressure oil to brake device or auxiliary brake, brake operation valve is operated from brake operation sensor, vehicle speed from speed sensor is zero, and accumulator hydraulic pressure from pressure sensor And a control means for outputting a switching signal to the electromagnetic valve and the brake electromagnetic valve when receiving a signal exceeding a predetermined pressure.

  According to a fifth aspect of the invention, there is provided a rotational speed sensor for detecting the rotational speed of the engine, and a control means for outputting a switching signal to the electromagnetic valve when receiving a signal from the rotational speed sensor that the rotational speed of the engine exceeds a predetermined value. It is characterized by becoming.

  According to the first invention, in the industrial vehicle having a work machine, the brake device circuit is provided with the solenoid valve that supplies the brake oil discharged from the brake hydraulic pump to the work machine when traveling is stopped. As a result of this support, the amount of oil supplied to the work machine can be increased without increasing the discharge volume of the working hydraulic pump, and the speed of cargo handling can be increased. Further, since it is not necessary to increase the discharge volume of the working hydraulic pump, the load on the engine can be reduced, and the engine can be downsized. Alternatively, since the oil discharged from the brake hydraulic pump is directly returned to the tank, the load on the engine required for braking the vehicle can be reduced, and the engine can be downsized and the fuel efficiency can be improved.

  According to the second invention, an accumulator for supplying pressure oil to the brake device is provided, and when the signal that the hydraulic pressure exceeds a predetermined pressure from the pressure sensor and the signal from the speed sensor that the vehicle speed is zero are received, the control means Switches the solenoid valve so that the oil discharged from the brake hydraulic pump is supplied to the operation valve. As a result, the oil discharged from the brake hydraulic pump is supplied to the work machine and the work machine can be operated quickly, and the brake device stops the vehicle by the pressure oil from the accumulator. The engine power required for the brake device can be turned to the work machine, and the engine can be downsized.

  According to the third invention, the brake device is provided with an auxiliary brake, and at least when the vehicle speed is zero, the brake is actuated by a command from the control means to stop the vehicle and switch the solenoid valve to operate the discharge oil of the brake hydraulic pump. Supply to the valve. As a result, the vehicle can be stopped by the auxiliary brake, and the work implement can be quickly operated as described above, and the engine power can be turned to the work implement to reduce the size of the engine. Further, it is only necessary to provide the brake device with an auxiliary brake operated by the control means, and the configuration can be simplified. Further, when the auxiliary brake is switched by a switch or the like, the operator does not need to operate the brake device, and the burden is reduced.

  According to the fourth aspect of the present invention, the accumulator for supplying pressure oil to the brake device or the auxiliary brake and the electromagnetic valve for brake for supplying the pressure oil of the accumulator to the brake device or the auxiliary brake are provided, and the control means is configured so that the hydraulic pressure of the accumulator is pressure. When receiving a signal exceeding a predetermined pressure from the sensor and a signal indicating that the vehicle speed from the speed sensor is zero, the brake solenoid valve is switched so that the pressure oil of the accumulator is supplied to the brake device or the auxiliary brake. Thereby, the same effect as the third invention can be obtained. Similarly to the above, when the brake solenoid valve is switched by a switch or the like, the vehicle can be stopped by the pressure oil from the accumulator, so that the operator does not need to operate the brake device and the burden is reduced.

  According to the fifth invention, the engine is provided with a rotation speed sensor for detecting the rotation speed, and the control means receives the discharge oil of the brake hydraulic pump when receiving a signal from the rotation speed sensor that the engine rotation speed exceeds a predetermined value. Switch to supply to the operation valve. As a result, engine stall can be reliably prevented because the engine speed exceeds a predetermined value. Further, as described above, the pressure oil of the accumulator is supplied to the brake device, so that the power of the engine can be saved and the working machine can be operated quickly.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a hydraulic brake device for an industrial vehicle according to the present invention will be described with reference to the drawings.
1 is a hydraulic circuit diagram of a hydraulic brake device and a working device for an industrial vehicle according to Embodiment 1 of the present invention.
FIG. 2 is a diagram for explaining a brake operation valve and an accumulator circuit constituting the hydraulic circuit diagram of the hydraulic brake device and the working device for the industrial vehicle according to the first embodiment of the present invention.
FIG. 3 is a flowchart showing the operation of the hydraulic brake device and the working device for the industrial vehicle according to the first embodiment of the present invention.

As shown in FIG. 1, a hydraulic brake device 3 and a work device 5 are mounted on an industrial vehicle 1, and a brake hydraulic pump 7 (hereinafter referred to as a brake pump 7) and a work machine, which are hydraulic sources thereof. A hydraulic pump 9 (hereinafter referred to as a work machine pump 9) is attached to an engine 11 that is a drive source. Both pumps 7 and 9 are rotated by the engine 11, and both pumps suck oil from a tank 13. ing.
The brake pump 7 is connected to the port 17a of the solenoid valve 17 at the 3 port 2 position by the first pipe 15, and the solenoid valve 17 has the 1 port 17b connected to the brake operation valve 21 by the second pipe 19. The other 1 port 17 c is connected to the work operation valve 31 via the third pipe 23 and the fourth pipe 27.

In the second pipe 19 to the brake operation valve 21, a fifth pipe 33 is branched on the way, and the fifth pipe 33 is connected to the accumulator 35. The accumulator 35 is connected to the brake operation valve 21 by a sixth pipe 37 and is provided with a pressure sensor 39. The hydraulic pressure is detected and transmitted to the control means 41.
The brake operation valve 21 has one port 21a connected to a wheel cylinder 45 by a seventh pipe 43. The wheel cylinder 45 extends by receiving pressure oil and extends a pad 47 to brake the vehicle. A speed sensor 49 is attached to the wheel, and the speed sensor 49 detects the vehicle speed and transmits it to the control means 41. Further, the other 1 port 21 b is connected to the tank 13 by an eighth pipe 51.

A brake petal 22 is attached to the brake operation valve 21, and the brake petal 22 is operated by an operator. The brake operation valve 21 receives the oil discharged from the brake pump 7 from the first pipe 15, the electromagnetic valve 17 and the second pipe 19 when not operated, and then returns to the tank 13 through the eighth pipe 51. The oil returning from the brake pump 7 to the tank 13 is squeezed according to the operation amount of the brake petal 22 to increase the pressure.
The raised pressure oil is supplied to the wheel cylinder 45 through the seventh pipe 43, and the wheel cylinder 45 is extended to expand the pad 47, thereby braking the vehicle.

A brake operation sensor 52 is attached to the brake petal 22, and the brake operation sensor 52 detects whether or not the brake petal 22 has been operated and transmits it to the control means 41. The control means 41 receives a signal indicating that the brake petal 22 has been operated from the brake operation sensor 52, a signal indicating that the vehicle speed is zero from the speed sensor 49, and a signal indicating that the accumulated pressure of the accumulator 35 exceeds a predetermined pressure from the pressure sensor 39. When received, a switching signal is output to the electromagnetic valve 17.
At this time, when the brake petal 22 is operated to a position where the vehicle is stopped, the brake operation valve 21 supplies the pressure oil of the accumulator 35 to the wheel cylinder 45, and the wheel cylinder 45 is extended to expand the pad 47. The vehicle is stopped.

  The work pump 9 is connected to the work operation valve 31 by a fourth pipe 27, and the third pipe 23 from the electromagnetic valve 17 is connected to the fourth pipe 27. The work operation valve 31 receives the oil discharged from the brake pump 7 through the solenoid valve 17, the third pipe 23 and the fourth pipe 27. The work operation valve 31 is connected to the work machine cylinder 55 by a ninth pipe 53 and to the tank 13 by a tenth pipe 57.

  The work operation valve 31 is operated by an operator. When the operation valve 31 is not operated, the oil discharged from the work pump 9 is returned to the tank 13 through the tenth pipe 57, and to the work machine cylinder 55 through the ninth pipe 53 during the operation. While supplying and discharging, the return oil of the working machine cylinder 55 is returned to the tank 13 through the eleventh pipe 59, and the working machine cylinder 55 is expanded and contracted. As the work machine cylinder 55 expands and contracts, the industrial vehicle 1 performs a cargo handling operation.

Next, an example of the brake operation valve and accumulator circuit of the hydraulic brake device according to the first embodiment of the present invention will be described with reference to FIG.
The brake operation valve 21 is provided with a brake petal 22 and a spring 21c on one end side, and a piston 21d and a spring 21e on the opposite side. Pilot pressure oil from the accumulator 35 is sent to the piston 21d. Have been paid. The brake operation valve 21 is formed by a 4-port 4-position servo valve, and is controlled by the operation force of the brake petal 22 and the pilot pressure of the accumulator 35.

The brake operation valve 21 includes (1) the position A when the brake petal 22 is not operated and the pressure of the accumulator 35 exceeds a predetermined pressure, and (2) the brake petal 22 is not operated and the accumulator 35 B position when the pressure is less than or equal to a predetermined pressure, (3) C position when the brake petal 22 is operated and the pressure of the accumulator 35 exceeds the predetermined pressure, and (4) The brake petal 22 is operated. And it is formed by D position when the pressure of the accumulator 35 is below a predetermined pressure.
In the circuit of the accumulator 35, a switching valve 61 and a check valve 63 are arranged in the fifth pipe 33 from the branch point W of the second pipe 19 toward the accumulator 35. The switching valve 61 is provided with a spring 61a on one end side and a piston 61b on the other end side, and pilot pressure oil from the accumulator 35 is supplied to the piston 61b.

  In the above configuration, when the brake operation valve 21 is in the A position, the brake operation valve 21 is not operated, and the discharge oil from the brake pump 7 is discharged from the first pipe 15, the electromagnetic valve 17 and the second pipe 19. It is returned to the tank 13 via the eighth pipe 51. In the brake operation valve 21, the circuit of the brake pump 7 is connected to the wheel cylinder 45 and the tank 13, and the wheel cylinder 45 is contracted and the vehicle is not braked.

  The switching valve 61 to the accumulator 35 is in the S position where the piston 21d receives the pressure oil from the accumulator 35 and shuts off the brake pump 7 and the accumulator 35. As a result, the oil discharged from the brake pump 7 circulates between the pump 13 and the tank 13 at a low pressure, and the vehicle travels normally according to an accelerator petal (not shown).

When the brake operation valve 21 is in the B position, the brake operation valve 21 is not operated, and the pressure oil in the accumulator 35 is equal to or lower than a predetermined pressure. Therefore, the brake operation valve 21 includes the piston 21d and the spring 21e. The force of the spring 21c is larger than the force of, and a spool (not shown) slides to the B position.
In the B position, the discharge oil of the brake pump 7 reaches the brake operation valve 21 via the first pipe 15, the electromagnetic valve 17 and the second pipe 19, but the discharge oil is blocked by the brake operation valve 21. The pressure rises. Further, the brake operation valve 21 connects the wheel cylinder 45 and the tank 13, and the wheel cylinder 45 is reduced in pressure to be reduced, and the vehicle is not braked.

Further, the switching valve 61 to the accumulator 35 has a force of the spring 61a larger than that of the piston 61b, and a spool (not shown) slides to the communication R position. As a result, the pressure of the oil discharged from the brake pump 7 rises due to the shut-off of the brake operation valve 21, and this pressure oil is charged into the accumulator 35 through the R position where the switching valve 61 is communicated. At this time, the vehicle travels normally according to an accelerator petal (not shown).
When the accumulator 35 is filled with pressure oil and the pressure exceeds a predetermined pressure, the brake operation valve 21 is switched from the B position to the A position, and the discharge oil from the brake pump 7 is at a low pressure with the pump and the tank 13. Circulating between.

When the brake operation valve 21 is in the C position, the brake operation valve 21 is operated, and the spool or the like (not shown) is in accordance with the operation amount of the brake petal 22 against the force of the piston 21d and the spring 21e. Has moved.
In the position C, the oil discharged from the brake pump 7 reaches the brake operation valve 21 via the first pipe 15, the electromagnetic valve 17 and the second pipe 19, and the wheel cylinder 45 and the accumulator 35 are connected to the brake operation valve 21. ing. The oil discharged to the brake pump 7 is squeezed into the tank 13 to increase its pressure, extend the wheel cylinder 45, and operate the pad 47 according to the operation amount (depression amount) of the brake petal 22. To brake the vehicle.

Further, at the position C, the wheel cylinder 45 is pressurized oil from the brake pump 7 to the wheel cylinder 45 when the oil discharged from the brake pump 7 runs out, that is, when the brake pump 7 supports the work pump 9. When the supply of the oil is delayed, or when the brake pump 7 is out of order, etc., the pressure oil from the accumulator 35 is received for braking.
Further, the switching valve 61 to the accumulator 35 is in the shut-off S position upon receiving the pressure oil of the accumulator 35 and shuts off the brake pump 7 and the accumulator 35. As a result, at the position C, the discharge oil from the brake pump 7 is fed to the wheel cylinder 45 at a high pressure to apply braking pressure to the vehicle, the vehicle stops, and the discharge oil from the brake pump 7 works. When the pump 9 is turned to support, braking is performed by the pressure oil of the accumulator 35.

When the brake operation valve 21 is in the D position, the brake operation valve 21 is being operated. The spool (not shown) operates the brake petal 22 against the small force of the piston 21d and the force of the spring 21e. Move according to the amount.
At the position D, the discharge oil of the brake pump 7 reaches the brake operation valve 21 via the first pipe 15, the electromagnetic valve 17 and the second pipe 19, and is connected to the wheel cylinder 45 in the brake operation valve 21. The oil discharged from the brake pump 7 is squeezed back to the tank 13 by the brake petal 22 to increase the pressure, extend the wheel cylinder 45, and operate the pad according to the operation amount (depression amount) of the brake petal 22 To brake the vehicle.

In the D position, the accumulator 35 is below a predetermined pressure, and the brake pump 7 and the wheel cylinder 45 are shut off. In the switching valve 61 to the accumulator 35, the force of the spring 61a is larger than the force of the piston 61b, and a spool (not shown) slides to the communication R position. As a result, the pressure of the oil discharged from the brake pump 7 is increased by the throttle of the brake operation valve 21, and this pressure oil is filled into the accumulator 35 through the R position where the switching valve 61 communicates. Pressure oil is fed from the brake operation valve 21 to the wheel cylinder 45. At this time, the vehicle obtains braking according to the accelerator petal, and the accumulator 35 is filled with pressure oil.
When the accumulator 35 is filled with the pressure oil and the pressure exceeds a predetermined pressure, the brake operation valve 21 is switched from the D position to the C position, and the discharge oil from the brake pump 7 supports the work pump 9. It becomes possible.

  In addition, as a spool type brake operation valve not shown above, a plurality of divided spools are inserted or juxtaposed with each other so that the spool receives the force of the springs 21c and 21e or the force of the piston 21d, respectively. It is configured. When the spool is in the C position as described above, it is connected to the tank via the variable throttle in the drawing, but when the vehicle is stopped, the connection between the accumulator 35 and the tank 13 is cut off and the accumulator is connected. 35 may be connected only to the wheel cylinder 45.

Next, a flowchart of the operation of the hydraulic brake device according to the first embodiment of the present invention will be described with reference to FIG.
In step 1, the pressure sensor 39 detects the pressure of the pressure oil accumulated in the accumulator 35 and transmits it to the control means 41. The control means 41 determines whether the pressure of the accumulator 35 has exceeded a predetermined pressure (OK) or not (NO). If the pressure is below the predetermined pressure (NO), step 1 is repeated, and the pressure sensor 39 detects the pressure. To do. If the pressure exceeds the predetermined pressure, go to step 2.

  In step 2, the brake operation sensor 52 detects whether or not the brake petal 22 has been operated (depressed) and transmits it to the control means 41. When the brake petal 22 is not operated, the control means 41 returns to step 2 and repeats the detection. Alternatively, the process returns to step 1 and starts by detecting the pressure. If the brake petal 22 has been operated, go to step 3.

  In step 3, the speed sensor 49 detects whether or not the vehicle is stopped (vehicle speed is zero km), that is, whether or not the wheel is rotating, and transmits it to the control means 41. If the wheel is rotating, the control means 41 determines that the vehicle is traveling, and goes to step 4. In step 4, the control means 41 does not output a command to the electromagnetic valve 17 and takes the position shown in FIG. 1, and the oil discharged from the brake pump 7 is fed to the wheel cylinder 45 and the tank 13 via the brake operation valve 21. The

  If the wheel is not rotating, the control means 41 determines that it is stopped (OK), and goes to step 5 and step 6. In step 5, the control means 41 outputs a command to the electromagnetic valve 17 to operate it, switches the electromagnetic valve 17 to the F position (shown in FIG. 1), and discharges the oil discharged from the brake pump 7 to the third pipe 23, The oil is fed to the work operation valve 31 through the four pipes 27.

  In step 6, the control means 41 receives a signal indicating that the brake petal 22 is operated, the vehicle speed is zero, and the accumulated pressure in the accumulator 35 exceeds a predetermined pressure. 35 pressure oil is supplied to the wheel cylinder 45. At this time, the control means 41 is good to detect the time after a wheel started a stop, and to output a command to the solenoid valve 17 when the predetermined time passes.

  As described above, since the oil discharged from the brake pump 7 is fed to the operation valve 31 for operation when traveling is stopped and is added to the oil discharged from the work pump 9 for support, the work machine required for the cargo handling operation at the time of stoppage. The oil supply capacity can be increased, and the speed of cargo handling work can be increased. In addition, the work pump 9 does not need to increase its discharge volume (cc / rev) to receive support, and is braked by the accumulated pressure of the accumulator 35. Therefore, the load applied to the engine 11 can be reduced. Can be miniaturized.

Next, Embodiment 2 of the present invention will be described with reference to FIGS.
FIG. 4 is a hydraulic circuit diagram of an industrial vehicle hydraulic brake device and working device according to Embodiment 2 of the present invention.
FIG. 5 is a flowchart showing the operation of the hydraulic brake device and the working device for an industrial vehicle according to the second embodiment of the present invention.
The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the first embodiment, another port 17 c of the electromagnetic valve 17 is connected to the fourth pipe 27 that connects the work pump 9 and the work operation valve 31 via the third pipe 23. On the other hand, in the second embodiment of FIG. 4, the other port 17 c of the electromagnetic valve 17 is connected to the eleventh pipe 59 that connects the work operation valve 31 and the tank 13 through the twelfth pipe 60. Yes.

Next, the operation of the hydraulic brake device 3A according to the second embodiment will be described with reference to the flowchart of FIG. In addition, in the case of the same content as the flowchart figure of Example 1 of FIG. 3, the same step code | symbol is attached | subjected and description is abbreviate | omitted.
In the flowchart of the hydraulic brake device 3 </ b> A according to the second embodiment in FIG. 5, step 5 in the flowchart in FIG. 3 according to the first embodiment is changed to step 7. In step 7, the control means 41 outputs a command to the solenoid valve 17 to operate, switches the solenoid valve 17 to the F position, and returns the discharge oil of the brake pump 7 directly to the tank 13 via the twelfth pipe 60. Yes.

In the second embodiment, when the vehicle is stopped, the oil discharged from the brake pump 7 is returned directly from the eleventh pipe 59 to the tank 13 without supporting the work pump 9. Thereby, when the vehicle is stopped, no load is applied to the brake pump 7, and engine stall of the engine 11 and energy consumption can be achieved.
Further, it is effective when the industrial vehicle 1 is operated while slowly adjusting the work implement, such as centering or alignment that does not require the work handling speed of the work implement when the vehicle is stopped.

Next, Embodiment 3 of the present invention will be described with reference to FIGS.
FIG. 6 is a hydraulic circuit diagram of an industrial vehicle hydraulic brake device and working device according to Embodiment 3 of the present invention.
FIG. 7 is a flowchart showing the operation of the hydraulic brake device and work device for an industrial vehicle according to Embodiment 3 of the present invention.
The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the first embodiment of FIG. 1, the solenoid valve 17 at the 3 port 2 position is used, and the other 1 port 17 c of the solenoid valve 17 is connected to the work pump 9 and the work operation valve 31 through the third pipe 23. Connected to the fourth pipe 27. On the other hand, the third embodiment of FIG. 6 uses the solenoid valve 17A at the 4 port 3 position. The solenoid valve 17A has the port 17a connected to the brake pump 7 by the first pipe 15, and the 1 port 17b. The second pipe 19 leads to the brake operation valve 21, the 1 port 17 c passes through the third pipe 23 and the fourth pipe 27 to the work operation valve 31, and the 1 port 17 d goes to the 13th pipe 61 and the 11th pipe. It is connected to the tank 13 via 59.

The electromagnetic valve 17A receives oil discharged from the brake pump 7 and feeds it to the brake operation valve 21 at the G position, to the work operation valve 31 at the H position, and to the tank 13 at the J position. ing.
In the third embodiment, the engine 11 is provided with a rotation speed sensor 65, and the rotation speed sensor 65 detects the rotation speed of the engine 11 and transmits it to the control means 41.

Next, the operation of the hydraulic brake device 3B according to the third embodiment will be described with reference to the flowchart of FIG. In addition, in the case of the same content as the flowchart figure of Example 1 of FIG. 3, the same step code | symbol is attached | subjected and description is abbreviate | omitted.
In the flowchart of the hydraulic brake device 3B according to the third embodiment in FIG. 7, step 5 of the flowchart in FIG. 3 according to the first embodiment is changed to step 8, step 9 and step 10. If the vehicle is stopped by the speed sensor 49 in step 3, that is, if the wheel rotation speed is detected as zero, the process goes to step 8.

  In step 8, the rotational speed sensor 65 detects whether or not the rotational speed of the engine 11 has exceeded a predetermined value (OK) and transmits it to the control means 41. The control means 41 goes to step 9 when the rotational speed of the engine 11 exceeds a predetermined value. In step 9, the electromagnetic valve 17 </ b> A is switched from the G position to the H position by a command from the control means 41. As a result, the oil discharged from the brake pump 7 is supplied to the work operation valve 31 via the third pipe 23 and the fourth pipe 27.

The control means 41 goes to step 10 when the rotational speed of the engine 11 is below a predetermined value (NO). In step 10, the electromagnetic valve 17 </ b> A is switched from the G position to the J position by a command from the control means 41. As a result, the oil discharged from the brake pump 7 is returned directly to the tank 13.
In the H position, the oil discharged from the brake pump 7 is fed to the operation valve 31 for operation when traveling is stopped, and is added to the oil discharged from the work pump 9 to support it. The speed of the cargo handling work can be increased and the load applied to the engine 11 can be reduced, and the engine 11 can be downsized. Further, at the position J, the oil discharged from the brake pump 7 is directly returned to the tank 13 without supporting the work pump 9, so that the same effect as in the second embodiment can be obtained, and the engine 11 can be prevented from stalling and energy consumption can be reduced. Can be planned.

Next, Embodiment 4 of the present invention will be described with reference to FIGS.
FIG. 8 is a hydraulic circuit diagram of an industrial vehicle hydraulic brake device and working device according to Embodiment 4 of the present invention.
FIG. 9 is a flowchart showing the operation of the hydraulic brake device and work device for an industrial vehicle according to Embodiment 4 of the present invention.
The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the first embodiment shown in FIG. 1, the accumulator 35 is used. When the brake petal 22 is stepped on and the vehicle is stopped, and the accumulated pressure in the accumulator 35 exceeds a predetermined pressure, the pressure oil in the accumulator 35 is removed from the wheel cylinder. The vehicle is stopped at 45. On the other hand, in the fourth embodiment of FIG. 8, the auxiliary brake 67 is mounted on the wheel, the brake operation valve 21 is changed to the brake operation valve 21A at the 3-port 2-position, and the auxiliary brake 67 and A control means 41A for outputting a command to the electromagnetic valve 17 is used.

As the auxiliary brake 67, for example, an electromagnetic brake is used, and the electromagnetic brake is connected to the control means 41A, operates according to a command from the control means 41A, and stops the vehicle.
In the brake operation valve 21A, the 1 port 21e receives the discharged oil from the brake pump 7, the 1 port 21a is tanked by the seventh pipe 43 to the wheel cylinder 45, and the other 1 port 21b is tanked by the eighth pipe 51. 13 are connected to each other.

  The brake operation valve 21A is provided with a brake petal 22 in the same manner as described above. When the brake petal 22 is not operated, oil discharged from the brake pump 7 is supplied to the first pipe 15, the electromagnetic valve 17 and the second pipe 19. After being received from the tank, it is returned to the tank 13 through the eighth pipe 51. Further, during operation, the oil returning from the brake pump 7 to the tank 13 is squeezed according to the operation amount to increase the pressure, and the pressure oil is supplied to the wheel cylinder 45 through the seventh pipe 43 to extend the wheel cylinder 45 and to pad. 47 is extended to brake the vehicle.

Next, the operation of the hydraulic brake device 3C according to the fourth embodiment will be described with reference to the flowchart of FIG. In addition, in the case of the same content as the flowchart figure of Example 1 of FIG. 3, the same step code | symbol is attached | subjected and description is abbreviate | omitted.
In the flowchart of the hydraulic brake device 3C in the fourth embodiment shown in FIG. 9, step 1 shown in the flowchart of FIG. 3 according to the first embodiment is omitted, and step 6 is changed to step 11. When the vehicle detected by the speed sensor 49 in step 3 is stopped, that is, when the wheel rotation speed is zero, the process goes to step 5 and step 11.

In step 11, the control means 41A outputs a command to the auxiliary brake 67 to stop the vehicle. Further, the control means 41 </ b> A determines in step 2 and step 3 and outputs a command to the electromagnetic valve 17 in step 5.
Thus, the configuration is simplified by using the auxiliary brake 67 instead of the accumulator 35, and the same effects as those of the second embodiment are obtained, and engine stall of the engine 11 and energy consumption can be achieved.

Next, Embodiment 5 of the present invention will be described with reference to FIGS.
FIG. 10 is a hydraulic circuit diagram of an industrial vehicle hydraulic brake device and working device according to Embodiment 5 of the present invention.
FIG. 11 is a flowchart showing the operation of the hydraulic brake device and work device for an industrial vehicle according to Embodiment 5 of the present invention.
The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  10 differs from the hydraulic brake device 3A of FIG. 4 in that the accumulator 35 is changed to an auxiliary brake 67 as in the hydraulic brake device 3C of FIG.

Next, the operation of the hydraulic brake device 3D according to the fifth embodiment will be described with reference to the flowchart of FIG. In addition, in the case of the same content as the flowchart figure of Example 1 of FIG. 3, the same step code | symbol is attached | subjected and description is abbreviate | omitted.
In the flowchart of the hydraulic brake device 3D according to the fifth embodiment shown in FIG. 11, step 1 is omitted and step 6 is changed to step 11 with respect to the flowchart shown in FIG. In step 11, the control means 41 </ b> A is changed so as to output a command to the auxiliary brake 67. Further, the control means 41 </ b> A determines in step 2 and step 3 and outputs a command to the electromagnetic valve 17 in step 7.

Next, Embodiment 6 of the present invention will be described with reference to FIGS.
FIG. 12 is a hydraulic circuit diagram of an industrial vehicle hydraulic brake device and working device according to Embodiment 6 of the present invention.
FIG. 13 is a flowchart showing the operation of the hydraulic brake device and work device for an industrial vehicle according to Embodiment 6 of the present invention.
The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  12 differs from the hydraulic brake device 3B of FIG. 6 in that the accumulator 35 is changed to an auxiliary brake 67 in the same manner as the hydraulic brake device 3C of FIG.

  Further, in the flowchart of the hydraulic brake device 3E of the sixth embodiment shown in FIG. 13, step 1 is omitted and step 6 is changed to step 11 with respect to the flowchart shown in FIG. In step 11, the first control means 41 </ b> A is changed so as to output a command to the auxiliary brake 67 as described above. Further, the control means 41 </ b> A determines in Step 2, Step 3 and Step 8, and outputs a command to the electromagnetic valve 17 in Step 9 and Step 10.

Next, Embodiment 7 of the present invention will be described with reference to FIG.
FIG. 14 is a diagram illustrating a brake operation valve and an accumulator circuit constituting a hydraulic circuit diagram of a hydraulic brake device and a working device for an industrial vehicle according to a seventh embodiment of the present invention.
The same parts as those in the first embodiment shown in FIG.

  In the hydraulic brake device 3 according to the first embodiment, for example, as shown in FIG. 2, an accumulator 35 is connected to one port of the brake operation valve 21 by a sixth pipe 37, and pilot pressure oil is sent to a piston 21d. I am paying. As a result, the brake operation valve 21 stops the vehicle by supplying the pressure oil of the accumulator 35 to the wheel cylinder 45 at the position C when the vehicle is stopped.

  On the other hand, in the hydraulic brake device 3F according to the seventh embodiment of the present invention shown in FIG. 14, the accumulator 35 supplies the pilot pressure oil to the piston 21d and the wheel cylinder 45 via the electromagnetic valve 69 for brake. Connected and feeding pressure oil. The accumulator 35 switches the brake operation valve 21B to the M position at a low pressure so that the discharge oil of the brake pump 7 can be stored in the accumulator 35, and at the time of stoppage, is supplied to the wheel cylinder 45 through the brake electromagnetic valve 69. The vehicle is stopped.

In FIG. 14, in the hydraulic brake device 3 </ b> F, a fourteenth pipe 71 is branched from between the check valve 63 and the accumulator 35. The fourteenth pipe 71 is connected to a seventh pipe 43 that connects the brake operation valve 21 </ b> B and the wheel cylinder 45, and the brake solenoid valve 69 and the brake check are sequentially turned from the accumulator 35 toward the wheel cylinder 45. A valve 73 is provided.
The brake solenoid valve 69 is formed by a 2-port 2-position, and switches from the shut-off K position to the communicating L-position in response to a command from the control means 41B.

Next, the operation in the above configuration will be described.
When the pressure oil in the accumulator 35 falls below a predetermined pressure, the force of the piston 21d decreases, the force of the spring 21c becomes larger than the resultant force of the piston 21d and the spring 21e, and the brake operation valve 21B is switched to the M position. As in the previous example, the brake pump discharge oil is blocked by the brake operation valve 21B and becomes high pressure, and this pressure oil is filled into the accumulator 35 through the R position where the switching valve 61 communicates. When the accumulator 35 exceeds a predetermined pressure, the second brake operation valve 21B is switched from the M position to the Q position, and the discharge oil of the brake pump is returned to the tank 13.

When the brake petal 22 is stepped on while the vehicle is running, the second brake operation valve 21B moves to a position where a spool or the like (not shown) is moved to the N position, and the wheel is discharged through the seventh pipe 43 using the brake pump discharge oil as a high pressure. Feeds to the cylinder 45 to brake the vehicle.
When the vehicle stops, the brake operation sensor 52 detects that the brake petal 22 has been depressed, the speed sensor 49 detects that the vehicle speed has become zero, and the pressure sensor 39 detects that the accumulator 35 exceeds a predetermined value. Then, the signal is transmitted to the control means 41B.

The control means 41B receives this signal and outputs a command to the solenoid valve 17 and the brake solenoid valve 69 to switch the solenoid valve 17 to the F position and switch the brake solenoid valve 69 to the L position.
As a result, the pressure oil in the accumulator 35 is supplied to the wheel cylinder 45 through the brake solenoid valve 69, the brake check valve 73, and the seventh pipe 43 to extend the wheel cylinder 45 and expand the pad 47. Continue to stop the vehicle.

Further, the oil discharged from the brake pump 7 is supplied to the operation valve 31 via the electromagnetic valve 17, the third pipe 23, and the fourth pipe 27. At this time, when the operation valve 31 is not operated, the discharge oil of the work pump 9 and the brake pump 7 is returned to the tank 13 by the tenth pipe 57, and the pressure oil is supplied by the ninth pipe 53 during the operation. The work equipment cylinder 55 is supplied and discharged, and the work equipment cylinder 55 is expanded and contracted to perform a cargo handling operation.
As a result, the hydraulic brake device 3F of the seventh embodiment can speed up the cargo handling operation and reduce the size of the engine 11 as described above.

In addition to the above, when the vehicle is stopped, the brake solenoid valve 69 is operated via the control means 41B by a switch (not shown) to the L position, and the pressure oil in the accumulator 35 is sent to the wheel cylinder 45. Accordingly, the operator brakes the vehicle without continuing to step on the brake petal 22 and continues the stop.
When traveling from this state is started, the depression of the brake petal 22 is stopped and the accelerator petal or the like is depressed to run the vehicle. At this time, the control means 41B switches off and puts the brake electromagnetic valve 69 into the K position, stops sending the pressure oil of the accumulator 35 to the wheel cylinder 45, and runs the vehicle. This eliminates the need for the operator to keep stepping on the brake petal 22 and facilitates driving.

  Furthermore, other hydraulic brake devices and work devices can be formed by appropriately combining the above configurations. For example, by using the accumulator 35, the hydraulic auxiliary brake, and the brake electromagnetic valve 69, another hydraulic brake device can be formed.

  In the above embodiment, an electromagnetic brake is used as the auxiliary brake 67. However, in the case of another hydraulic brake device, a hydraulic brake pad having a hydraulic brake pad outside the wheel cylinder 45 that extends the pad 47 is used. The auxiliary brake rotating disk is attached to the wheel. The hydraulic brake pad is actuated by pressure oil from the accumulator 35 and feeds pressure oil from the accumulator to the hydraulic auxiliary brake. At this time, similarly to the brake solenoid valve 69 of the seventh embodiment, the second control means 41B switches the brake solenoid valve 69 to supply the pressure oil of the accumulator to the hydraulic brake pad, so that the vehicle Let the stop continue.

In the above embodiment, the control means 41 detects whether or not the brake petal 22 has been operated (depressed) by the brake operation sensor 52. However, the control means 41 exceeds the stroke amount or position where the vehicle speed becomes zero. It may be determined by detecting whether or not the brake petal 22 has been operated.
Moreover, although the brake was demonstrated in the example using the pad 47, you may use a disc brake. Although the pressure oil is supplied to the accumulator 35 by the brake pump 7, a dedicated accumulator hydraulic pump for supplying the pressure oil only to the accumulator 35 is separately provided, and the pressure is accumulated with the discharged oil. You may make it unload the discharge oil of a hydraulic pump. Moreover, a pressure regulation valve, a safety valve, etc. can be used suitably.

1 is a hydraulic circuit diagram of a hydraulic brake device and a working device for an industrial vehicle according to a first embodiment of the present invention. It is a figure explaining the circuit of the brake operation valve and the accumulator which comprise the hydraulic brake device of the industrial vehicle which concerns on Example 1 of this invention, and the hydraulic circuit diagram of a working device. It is a flowchart figure about the action | operation of the hydraulic brake device of an industrial vehicle which concerns on Example 1 of this invention, and a working device. It is a hydraulic circuit diagram of the hydraulic brake device and working device of an industrial vehicle concerning Example 2 of the present invention. It is a flowchart figure about the action | operation of the hydraulic brake device of an industrial vehicle which concerns on Example 2 of this invention, and a working device. It is a hydraulic circuit diagram of the hydraulic brake device and working device of an industrial vehicle concerning Example 3 of the present invention. It is a flowchart figure about the action | operation of the hydraulic brake device and working apparatus of the industrial vehicle which concerns on Example 3 of this invention. It is a hydraulic circuit diagram of the hydraulic brake device and working device of an industrial vehicle concerning Example 4 of the present invention. It is a flowchart figure about the action | operation of the hydraulic brake device of an industrial vehicle which concerns on Example 4 of this invention, and a working device. It is a hydraulic circuit diagram of the hydraulic brake device and working device of an industrial vehicle concerning Example 5 of the present invention. It is a flowchart figure about the action | operation of the hydraulic brake device and working device of an industrial vehicle which concerns on Example 5 of this invention. It is a hydraulic circuit diagram of the hydraulic brake device and working device of an industrial vehicle concerning Example 6 of the present invention. It is a flowchart figure about the action | operation of the hydraulic brake device of an industrial vehicle which concerns on Example 6 of this invention, and a working device. It is a figure explaining the circuit of the brake operation valve and the accumulator which comprise the hydraulic brake device of the industrial vehicle which concerns on Example 7 of this invention, and the hydraulic circuit diagram of a working device. It is a hydraulic circuit diagram of a hydraulic brake device and a working device of an industrial vehicle according to the prior art.

Explanation of symbols

1, 1A, 1B, 1C, 1D, 1E ... industrial vehicles 3, 3A, 3B, 3C, 3D, 3E, 3F, hydraulic brake devices 5, 5A, 5B, 5C, 5D, 5E, ... work Device 7 ...... Brake hydraulic pump 9 ... Work machine hydraulic pump 11 ... Engine 13 ... Tank 17, 17A ... ..... Solenoid valves 21, 21A, 21B ..... Brake operation valve 22 ........... Brake petal 31.・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Operation valve 35 for work ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Accumulator 39 ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・Force sensor 41, 41A, 41B ... Control means 45 ... Wheel cylinder 49 ...・ ・ ・ ・ ・ ・ ・ ・ ・ Speed sensor 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Brake operation sensor 55 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ Working machine cylinder 65 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Rotational speed sensor 67 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Auxiliary brake 69 ... Brake solenoid valve

Claims (5)

Industrial vehicle having a brake device that brakes a vehicle by receiving discharge oil of a brake hydraulic pump from a brake operation valve, and a work device that operates a work machine by receiving discharge oil of a work hydraulic pump from a work operation valve In the hydraulic brake device of
A hydraulic brake device for an industrial vehicle, wherein an operation valve for operation or an electromagnetic valve connected to a tank is arranged between the brake hydraulic pump and the brake operation valve. From the accumulator that supplies pressure oil to the brake device, the pressure sensor that detects the hydraulic pressure of the accumulator, the speed sensor that detects the vehicle speed, the brake operation sensor that detects that the brake operation valve is operated, and the brake operation sensor Control means for outputting a switching signal to the electromagnetic valve when the brake operation valve is operated and the vehicle speed from the speed sensor is zero and the pressure sensor receives a signal indicating that the hydraulic pressure of the accumulator exceeds a predetermined pressure. The hydraulic brake device for an industrial vehicle according to claim 1, wherein   An auxiliary brake of a brake device that operates at least when the vehicle speed is zero, a speed sensor that detects the vehicle speed, a brake operation sensor that detects that the brake operation valve has been operated, and a brake operation valve from the brake operation sensor 2. The industrial vehicle according to claim 1, further comprising control means for outputting a switching signal to the solenoid valve and an operation signal to the auxiliary brake when a signal indicating that the vehicle speed from the speed sensor is zero is operated. Hydraulic brake device.   An accumulator that supplies pressure oil to the brake device or the auxiliary brake, a pressure sensor that detects the hydraulic pressure of the accumulator, a speed sensor that detects the vehicle speed, a brake operation sensor that detects that the brake operation valve has been operated, and an accumulator Brake solenoid valve that supplies the pressure oil to the brake device or auxiliary brake, the brake operation valve is operated from the brake operation sensor, the vehicle speed from the speed sensor is zero, and the hydraulic pressure of the accumulator exceeds the predetermined pressure from the pressure sensor 4. A control means for outputting a switching signal to the solenoid valve and the brake solenoid valve when receiving the signal, wherein the control signal is any one of claims 1 to 3. The hydraulic brake device for industrial vehicles described in 1.   A rotation speed sensor for detecting the rotation speed of the engine, and a control means for outputting a switching signal to the solenoid valve when receiving a signal from the rotation speed sensor that the engine rotation speed exceeds a predetermined value. The hydraulic brake device for an industrial vehicle according to any one of claims 2 to 4.

Images