JP2002114497A - Replenishment abnormality diagnostic device, accumulation abnormality diagnostic device, fluid type operation controller, hydraulic operation controller and brake device, for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To diagnose replenishment abnormality occurring in a system for replenishing a vessel with fluid, such as pressure accumulation abnormality such that an accumulator is not normally accumulated or that pressure accumulation operation continues though pressure accumulation is already completed, with a simple structure. SOLUTION: Auxiliary brake device 26 installed to front wheels 5 are connected to a brake valve unit 20 through pipes 27. When a microcomputer 53 decides that the auxiliary brake is necessary on the basis of detection values of various sensors 28, 32, 37, 38, 49, the microcomputer 53 controls solenoid valves 51, 52 to operate the auxiliary brake devices 26. When a pressure switch 48 detecting a pressure accumulation value of the accumulator 61 turns off, a controller 41 operates a pump motor 15 to accumulate the accumulator 61. The microcomputer 53 measures a start-up time and a start-up interval of the pump motor 15 on the basis of ON/OFF of the pressure switch 48, and diagnoses the accumulation as the accumulation abnormality when the time or the interval becomes a value impossible to occur in the normal time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for diagnosing abnormal replenishment in an industrial vehicle, such as a forklift, for diagnosing an abnormal replenishment (for example, an abnormal accumulator) for replenishing a container such as a pressure accumulator (accumulator). The present invention relates to an abnormality diagnosis device, a fluid operation control device, a hydraulic operation control device, and a brake control device.

[0002]

2. Description of the Related Art For example, a vehicle power transmission device disclosed in Japanese Patent Application Laid-Open No. 10-35313 is provided with a hydraulic unit for driving a differential device. Hydraulic unit includes motor pump, accumulator (accumulator), electromagnetic proportional pressure control valve (proportional valve) and electromagnetic directional switching valve (directional switching valve)
The accumulator functions as a hydraulic pressure source for a proportional valve that regulates the hydraulic pressure supplied to the oil chamber of one of the left and right clutches by a direction switching valve. The accumulation of pressure in the accumulator has been managed by controlling the operation of the motor pump based on the detection information of the pressure switch. For example, the pressure oil stored in the accumulator is consumed, and when the pressure value falls below the lower limit, the pressure switch is turned off and the electric motor connected to the motor pump is driven, and when the pressure value reaches the upper limit, the pressure switch is turned on. Then, the drive of the electric motor is stopped.

When an industrial vehicle is a battery vehicle, a method of generating a hydraulic pressure by driving an electric pump (comprising an electric motor and a hydraulic pump) is employed. For example, there is a demand for automatically controlling a hydraulic brake device. In this case, a configuration is conceivable in which a configuration similar to the above-described conventional hydraulic unit is applied to operate a hydraulic brake device with pressure oil from an accumulator. Since the brake is applied using the pressure oil constantly stored in the accumulator, the wheels can be applied early after the brake operation without being affected by the start delay of the electric pump.

[0004]

The accumulator has a structure in which the gas pressure inside the accumulator increases as the amount of accumulated pressure oil increases, so that the accumulator generates a certain level of hydraulic pressure. If the gas inside the accumulator gradually escapes and decreases during long-term use, the required amount of oil accumulated in the accumulator increases until the oil pressure reaches the upper limit, and after the pressure accumulation, the oil amount decreases only slightly. And the oil pressure immediately drops. Therefore, when this kind of outgassing abnormality occurs, 1
There has been a problem that the amount of pressurized oil that can be consumed in each pressure accumulating operation decreases, and the electric pump must be frequently driven.

When the pressure sensor fails due to disconnection or the like, the signal remains off, so that the electric pump continues to be driven uselessly. Also, if the oil passage connecting the pressure sensor and the accumulator becomes clogged, for example, if the hydraulic pressure of the accumulator is not transmitted to the pressure sensor, the electric pump will be driven uselessly with the pressure sensor off even though the accumulator is stored. The trouble that continues to occur occurs. In addition, if the oil passage that blocks the flow of pressure oil into the accumulator is blocked, the oil pressure on the oil passage on the pressure sensor side immediately after the start of the electric pump rises, and the pressure sensor is turned on even though the accumulator is not stored. Is turned on and the driving of the electric motor is stopped.

[0006] This is not limited to the case of using a hydraulic brake device, but is a problem that can occur even in a configuration using an accumulator as a hydraulic source of another hydraulic drive device such as a differential device. This kind of pressure accumulation abnormality may not only cause a trouble in the normal operation of the hydraulic drive unit, but also cause waste of power consumption due to useless driving of the electric pump. The waste of power consumption has a problem that, for example, a long-time running or a cargo handling operation while maintaining a high power of a battery-type forklift has a problem. In addition, in the event that a pressure accumulation abnormality occurs, there is a possibility that a hydraulic drive device such as a hydraulic brake device or a differential device using an accumulator as a hydraulic source may not be properly operated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to prevent a normal accumulation of pressure in a pressure accumulator or to perform a pressure accumulation operation despite the fact that pressure has already been accumulated. It is an object of the present invention to provide a replenishment abnormality diagnosis device and a pressure accumulation abnormality diagnosis device for an industrial vehicle that can diagnose a replenishment abnormality that occurs in a system for replenishing a fluid to a container, such as a continued accumulation accumulation abnormality, with a relatively simple configuration.

A second object is to provide a hydraulic system which is operated by a fluid (pressure oil) supplied from a container (accumulator) even when it is diagnosed that the fluid (pressure accumulator) is replenished abnormally. It is an object of the present invention to provide a hydraulic operation control device, a hydraulic operation control device, and a brake control device for an industrial vehicle that can operate an operation device such as a hydraulic drive device.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a method of detecting a fluid in a container when a sensor detects that the fluid amount or fluid pressure in the container falls below a lower limit value. In the replenishing device, the replenishing means is operated to increase the amount or the fluid pressure to perform the replenishment, and when the fluid amount or the fluid pressure in the container reaches the upper limit value and the sensor detects that, the replenishment operation is stopped. An abnormality diagnosing means for measuring information on the time of the replenishing operation based on the detection signal of the sensor, and diagnosing the abnormality of the replenishing device when the information on the time takes a value that cannot occur when the replenishing device is normal. The gist is that

According to the present invention, it is possible to diagnose an abnormality of the replenishing device by using a detection signal of a sensor for detecting a timing at which the replenishing device performs the replenishing operation. For this reason,
The supplementary abnormality diagnosis can be performed with a simple configuration without adding a sensor or the like dedicated to the abnormality diagnosis.

According to a second aspect of the present invention, there is provided a hydraulic drive device provided in an industrial vehicle, a pressure accumulator serving as a hydraulic pressure source of the hydraulic drive device, and a required amount of pressure oil stored in the pressure accumulator. Pressure accumulating detector for detecting whether or not the pressure accumulator, pressure accumulating operation means for accumulating pressure oil for supplying pressure oil to the accumulator, and detecting that the accumulated pressure value of the accumulator has fallen below a lower limit value by the accumulator. Activating the pressure accumulating operation means to perform a pressure accumulating operation for supplying pressure oil to the accumulator, and when the accumulator detects that the accumulated pressure value of the accumulator has reached an upper limit value, the accumulating operation is performed. The gist of the present invention is to provide a pressure accumulation control means for stopping and an abnormality diagnosis means for measuring time information relating to the pressure accumulation operation of the pressure accumulation operation means and diagnosing an abnormality relating to the pressure accumulator based on the time information. Note that the abnormality relating to the pressure accumulator is not limited to the abnormality of the pressure accumulator itself, but also includes an abnormality in which the pressure accumulation in the pressure accumulator is not performed normally or the pressure accumulator cannot function normally. The same applies to the following claims.

According to the present invention, time information relating to the pressure accumulating operation of the pressure accumulating means is measured, and based on this time information, the abnormality diagnosing means diagnoses a pressure accumulator abnormality with respect to the accumulator. For example, it is possible to discover an abnormality in which the pressure accumulation operation is wastefully continued due to a failure of the pressure accumulation detector or an abnormality in which the pressure oil is not normally accumulated in the accumulator.

According to a third aspect of the present invention, in the apparatus for diagnosing accumulated pressure abnormality in an industrial vehicle according to the second aspect, the hydraulic drive device is a hydraulic brake device provided for braking the industrial vehicle. That is the gist.

According to the present invention, it is possible to diagnose a pressure accumulation abnormality of the pressure accumulator which is a hydraulic pressure source of the hydraulic braking device. The invention according to claim 4 is a determining means for determining whether or not it is necessary to assist the braking of the driving wheel when the main braking means for braking the front wheel or the rear wheel which is the driving wheel is operated,
A hydraulic braking device that applies an auxiliary braking force to wheels opposite to the front and rear of the driving wheel; a pressure accumulator serving as a hydraulic oil pressure source for operating the hydraulic braking device; When it is determined that assistance is necessary, a brake control unit that supplies hydraulic oil of the pressure accumulator and performs hydraulic control to operate the hydraulic braking device, and a pressure accumulation detector that detects a pressure value of the pressure accumulator, Pressure accumulating means for accumulating pressure to supply pressure oil to the accumulator, and, when the accumulator detects that the accumulator value of the accumulator has fallen below a lower limit, activates the accumulator means. Pressure accumulation control means for causing a pressure accumulation operation to supply pressure oil to the pressure accumulator, and stopping the pressure accumulation operation when the pressure accumulation value of the pressure accumulation device reaches the upper limit value by the pressure accumulation detector; and Time information on the pressure accumulation operation of the operating means Constant, and the gist that a diagnosis means for diagnosing an abnormality relating to the accumulator on the basis of the time information.

According to the present invention, time information relating to the pressure accumulating operation of the pressure accumulating means is measured, and based on this time information, the abnormality diagnosing means diagnoses a pressure accumulator abnormality with respect to the accumulator. For example, it is possible to discover an abnormality in which the pressure accumulation operation is wastefully continued due to a failure of the pressure accumulation detector or an abnormality in which the pressure oil is not normally accumulated in the accumulator.

According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the time information measured by the abnormality diagnosing means is stored in the storage device after the start of the pressure accumulation operation. Pressure accumulation operation time until the accumulator value of the accumulator reaches the upper limit value and stops, and the abnormality diagnosing means sets the accumulator operation time of the accumulator to a value equal to or more than the normal maximum required time. The point is to diagnose that there is an abnormality related to the pressure accumulator when it exceeds.

According to the present invention, in the operation of the invention according to any one of claims 2 to 4, the pressure accumulation operation time from the start of the pressure accumulation operation of the pressure accumulation operation means to the stop thereof is measured. If the accumulating operation time exceeds a set time (a value equal to or longer than the maximum required time) that cannot occur during normal operation, the abnormality diagnosing means diagnoses as an abnormality relating to the accumulator. For example, pressure accumulation abnormalities such as disconnection of the signal line of the pressure accumulator and clogging of the oil passage between the pressure accumulators (clogging that prevents the pressure accumulator from detecting the oil pressure of the pressure accumulator) are found.

According to a sixth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the time information measured by the abnormality diagnosing means is stored in the storage device after the start of the pressure accumulating operation. Pressure accumulation operation time until the accumulator value of the accumulator reaches the upper limit value and stops, and the abnormality diagnosing means sets the accumulator operation time of the accumulator to a value equal to or less than a minimum required time in a normal state. The gist is to diagnose that there is an abnormality related to the pressure accumulator when it is short.

According to the present invention, in the operation of the invention according to any one of claims 2 to 4, the pressure accumulation operation time from the start of the pressure accumulation operation of the pressure accumulation operation means to the stop thereof is measured. If the accumulating operation time is shorter than a set time that cannot occur during normal operation (a value equal to or less than the minimum required time), the abnormality diagnosing unit diagnoses an abnormality relating to the accumulator. For example, a pressure accumulation abnormality such as a gas leak from the pressure accumulator or a clogging of an oil passage between the pressure accumulator and the pressure accumulation detector (clogging that interrupts the supply of pressure oil to the pressure accumulator) is found.

According to a seventh aspect of the present invention, in the invention according to any one of the second to fourth aspects, the time information measured by the abnormality diagnosing means is a start interval of a pressure accumulating operation of the accumulator. The abnormality diagnosis means detects an abnormality related to the pressure accumulator when detecting a short startup interval that is equal to or less than a set time interval that cannot occur in a normal state even when the hydraulic drive device or the hydraulic brake device is continuously operated. The gist is to diagnose that there is.

According to the present invention, in the operation of the invention according to any one of claims 2 to 4, the start interval of the pressure accumulating operation is measured, and the start interval is determined by the hydraulic driving device or the hydraulic braking device. If the set time interval is shorter than the set time interval that cannot occur in the normal state even if is continuously operated, it is diagnosed that the pressure accumulator is abnormal. For example, a pressure accumulation abnormality such as gas release from the pressure accumulator is found.

According to an eighth aspect of the present invention, in the invention according to any one of the second to seventh aspects, the abnormality diagnosing means stores the pressure of the pressure accumulating operation means based on a detection signal of the pressure accumulating detector. The gist is to measure time information on the operation.

According to the present invention, the abnormality diagnosing means measures time information relating to the pressure accumulation operation based on the detection signal of the pressure accumulation detector. Since the time information is obtained using the detection signal of the pressure accumulation detector, it is not necessary to provide a sensor or the like dedicated to the pressure accumulation abnormality diagnosis.

According to a ninth aspect of the present invention, in the invention according to any one of the second to eighth aspects, the pressure accumulating operation means includes: an electric motor; The gist consists of a hydraulic pump connected through an oil passage.

According to the present invention, in the invention according to any one of claims 2 to 8, the operation of accumulating the pressure in the accumulator is:
The operation is performed by the electric motor driving the hydraulic pump, and the pressure oil discharged from the hydraulic pump is accumulated in the accumulator. For example, if an abnormality in the pressure accumulation such as a disconnection of the signal line of the pressure accumulation detector is detected (excluding claims 6 and 7), a problem that the electric motor continues to be driven uselessly due to the abnormality in the pressure accumulation is avoided.

The invention according to claim 10 is the invention according to claims 4 to 9
In the invention according to any one of the above, in the industrial vehicle, the driving wheel to which the braking force is applied by the main braking unit is a rear wheel, and the wheel to which the auxiliary braking force is applied by the hydraulic braking device is In addition to the front wheels, the gist is a reach-type forklift in which the cargo handling device is mounted on the front side of the vehicle body so as to be movable back and forth.

According to the present invention, the vehicle center of gravity moves toward the front wheels when the cargo handling device is reached forward in the loaded state, so that the weight of the rear wheels, which are driving wheels, is relatively small.
When the main brake is applied by operating the brakes on a wet road surface or the like while traveling in this state, if it is determined that auxiliary braking is necessary due to, for example, slipping of a rear wheel (drive wheel), the hydraulic braking device is activated. As a result, auxiliary braking is applied to the front wheels. Since the front wheels have relatively increased wheel weight, auxiliary braking is firmly applied and the braking force required for the forklift is secured.

According to an eleventh aspect of the present invention, there is provided a fluid type operation control device for an industrial vehicle, wherein the replenishment abnormality diagnosing device according to the first aspect and an operating device operated by the fluid in the container. When the abnormality diagnosing unit diagnoses that there is an abnormality in the replenishing device, the control unit activates the replenishing device when it is recognized that the operating device is operating. I do. In addition,
“Recognition” means not only recognition by a computer or the like, but also “detection” by a sensor or the like.

According to the present invention, when the abnormality diagnosing means diagnoses that there is an abnormality in the replenishing apparatus, the control means activates the replenishing apparatus when recognizing that the operating apparatus is operating. For this reason, even if the fluid amount or fluid pressure in the container is insufficient due to the abnormality, the fluid is replenished (supplied) by the operation of the replenishing device at the time of operating the operating device, so that the operating device is almost normally operated. Operate.

The twelfth aspect of the present invention is directed to a hydraulic operation control apparatus for an industrial vehicle, wherein
The pressure accumulation abnormality diagnosis device according to any one of the above, when it is diagnosed by the abnormality diagnosis means that there is an abnormality relating to the pressure accumulator, when it is recognized that the hydraulic drive device is operating, the pressure accumulation The gist of the present invention is to provide control means for operating the operation means.

According to the present invention, when the abnormality diagnosing means diagnoses that there is an abnormality relating to the accumulator, the control means activates the pressure accumulating operation means when recognizing that the hydraulic driving device is operating. For this reason, even if the accumulator pressure is insufficient due to the abnormality, the hydraulic oil drive is operated normally because the hydraulic oil is supplied by the operation of the accumulator when the hydraulic drive is activated. I do.

A thirteenth aspect of the present invention is directed to a brake control device for an industrial vehicle, wherein
The pressure accumulation abnormality diagnostic device according to any one of the above, wherein when the abnormality diagnosis means diagnoses that there is an abnormality relating to the accumulator, it is determined by the determination means that it is necessary to assist the braking of the drive wheels When the hydraulic braking device is actuated by the braking control means, a control means for operating the pressure accumulating means and performing a pressure accumulating operation for supplying pressure oil to the accumulator is provided. .

According to the present invention, when the abnormality diagnosing means diagnoses that there is an abnormality relating to the pressure accumulator, it is determined that it is necessary to assist the braking of the drive wheels, and when the hydraulic braking device is operated, The control means operates the pressure accumulating operation means to perform a pressure accumulating operation for supplying pressure oil to the accumulator. For this reason,
Even if the accumulation of pressure in the accumulator becomes insufficient due to the abnormality, when the hydraulic braking device is operated, the hydraulic oil is supplied by the operation of the pressure accumulating operation means, so that the hydraulic braking device operates almost normally.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

As shown in FIGS. 10 and 11, a reach-type forklift truck (hereinafter simply referred to as a forklift) 1 as an industrial vehicle is a three-wheeled vehicle driven by two front wheels and driven by one rear wheel. This is a battery car that runs using the battery 3 housed in the front of the base 2 as a power source. A pair of left and right reach legs 4 extend forward from the vehicle body 2, and the left and right front wheels 5 are rotatably supported by the distal ends of respective reach rails 4 a constituting the left and right reach legs 4. The rear wheel 6, which is one rear wheel, is a driving wheel also serving as a steering wheel, and is offset to the left in the vehicle width direction, and an auxiliary wheel (caster) 7 is provided at a position away from the right by a predetermined distance. ing.

The rear right portion of the rear of the vehicle body 2 is a driver's seat (driver's cab) 8 of a standing type, and an instrument panel 9 shown in FIG. A lever 10 and an accelerator lever 11 for forward / reverse operation are provided. In addition, a steering wheel (steering wheel) 13 is provided on the upper surface of the storage box 12 erected to the left of the driver's seat 8. As shown in FIG. 11, a traveling motor (drive motor)
14. Cargo handling motor as electric motor (hereinafter referred to as pump motor) 15, Cargo handling pump 1 as hydraulic pump
6, an oil tank 18, an oil control valve (hereinafter referred to as a control valve) 19, a brake valve unit 20, and the like are housed.

As shown in FIG. 10, a mast device 21 as a cargo handling device is provided on the front side of the vehicle body 2, and when the reach lever of the cargo handling lever 10 is operated, the reach cylinder 22 is driven to expand and contract, thereby causing the mast device 21 to move. 21 moves forward and backward along the reach rail 4a within a predetermined stroke range. The mast device 21 includes a two-stage mast 23, a lift cylinder 24, and a fork 25. When the lift lever of the cargo handling lever 10 is operated,
When the lift cylinder 24 is driven to expand and contract, the mast 2
3 slides up and down and the fork 25 moves up and down in conjunction with this.

As shown in FIG. 11, both the brake valve unit 20 and the control valve 19 use the cargo handling pump 16 as a common hydraulic pressure source. A hydraulic drive device and a hydraulic auxiliary brake device (front wheel brake device) 26 as a hydraulic brake device are attached to the left and right front wheels 5, respectively. The auxiliary brake device 26 is a hydraulic drum brake device in this example. The left and right auxiliary brake devices 26 are connected to the brake valve unit 20 via two pipes 27, respectively.

Front wheel speed sensors 28, 28 are mounted on the lower surface of each reach rail 4a. The front wheel rotation speed sensor 28 is, for example, a magnetic sensor, and detects the rotation speed of the front wheel 5 by detecting a tooth portion formed at a constant pitch in the circumferential direction on the wheel side surface of the front wheel 5.

FIG. 1 is a schematic configuration diagram (system configuration diagram) of a forklift. The traveling motor 14 is mounted on an upper surface of a link member 30 constituting a rear suspension mechanism, and a rear wheel (drive wheel) is provided on a lower portion of a gear box 31 provided rotatably on a lower surface of the link member 30. 6
Are rotatably supported. A steering gear 31 a that rotates integrally with the gear box 31 is operatively connected to the handle 13, and the rear wheel 6 is steered according to the operation of the handle 13. A steering angle sensor 32 is provided near the steering gear 31a. The steering angle sensor 32 detects the rotational position of the steering gear 31a and outputs a signal of a voltage value corresponding to the steering angle (tire angle) of the rear wheel 6. Output.

A main brake device (rear wheel brake device) 33 as main braking means is provided above the traveling motor 14. The main brake device 33 is connected to the traveling motor 14.
And a disk brake device that obtains a braking force by pinching the disk 34 that rotates integrally with the rotation shaft of the disk. The main brake device 33 is mechanically operatively connected to a brake pedal 35 via a link mechanism (not shown).
This is a so-called deadman brake, in which the brake is applied in a state where step 5 is not depressed. Further, a brake switch 36 for detecting that the brake pedal 35 is at a brake operation position (stepping release position) is provided.

Two rotational speed sensors 37 and 38 having the teeth 34a as the detection target are located at positions opposed to the plurality of teeth 34a formed at a constant pitch in the circumferential direction on the outer peripheral surface of the support portion of the disk 34. Is provided. Two rotation speed sensors 3
7, 38 are arranged in parallel at positions shifted by 90 ° in the phase of the tooth portion, and output pulse signals shifted by 90 degrees in phase.

The controller 41 serving as the pressure accumulation control means and the control means includes, on the input side, a front wheel speed sensor 28, a steering angle sensor 32, a brake switch 36, a speed sensor 3
7, 38, an accelerator sensor 42, a forward operation detection switch 43, a reverse operation detection switch 44, a cargo handling operation detection switch 45, 46, 47, a pressure switch 48 as a sensor and a pressure accumulation detector, and a lift sensor 49 are electrically connected. It is connected. The pump motor 15 and the two solenoid valves 51 and 52 of the brake valve unit 20 are electrically connected to the output side of the controller 41. Further, the controller 41 incorporates a microcomputer 53 and a motor drive circuit 54 as abnormality diagnosis means. The determining means is composed of the sensors 28, 32, 37, 49 and the microcomputer 53. The braking control means includes the brake valve unit 20 and the microcomputer 53.

The brake switch 36 outputs a brake switch braking signal to the controller 41 upon detection of a brake operation in which the depression operation of the brake pedal 35 is released.
The accelerator sensor 42 detects the operating position of the accelerator lever 11 and outputs to the controller 41 a signal of a voltage value according to the amount of operation of the vehicle from the neutral position in forward and backward.

The controller 41 operates the accelerator lever 1 based on the input signals from the forward / reverse operation detection switches 43 and 44.
The operation amount of the accelerator lever 11 is recognized on the basis of the input signal value from the accelerator sensor 42 while recognizing the operation direction of No. 1. The controller 41 controls the drive of the traveling motor 14 via the motor drive circuit 54 so that a motor output corresponding to the operation amount is obtained in the motor rotation direction corresponding to the operation direction of the accelerator lever 11. Controller 4
1 sequentially detects the rotation direction of the rear wheel 6, that is, the traveling direction of the vehicle, by comparing the signal states of the pulse signals input from the two rotation speed sensors 37 and 38.
When a signal indicating that the operation direction 1 is opposite to the vehicle traveling direction (that is, a switchback operation) is input from the forward / reverse operation detection switches 43 and 44, this is recognized as an accelerator braking signal. The controller 41 determines that switchback is being performed during the input of the accelerator braking signal, and controls the regenerative braking of the traveling motor 14 via the motor drive circuit 54. The running motor 14 that applies regenerative braking to the rear wheel 6
The main braking means is also constituted by the motor drive circuit 54.

Cargo operation detection switches 45, 46, 47
Is the cargo handling lever (lift lever 10a, reach lever 1
0b, which detects that the tilt lever 10c) is operated, and is provided for each of the three levers 10a, 10b, 10c (however, the lowering operation of the lift lever 10a is not detected). The controller 41 operates the loading / unloading levers 10a, 10
When a signal indicating that b and 10c have been operated is input, the pump motor 15 is driven. When the pump motor 15 is driven, the cargo handling pump 16 is driven, and the hydraulic oil pumped up from the oil tank 18 through the hose 55 is discharged to the control valve 19 through the hose 56. The hydraulic oil discharged from the control valve 19 is returned to the oil tank 18 through the hose 57.

The loading levers 10a to 10c are mechanically connected to the control valve 19,
When 10 to 10c are operated, the pump motor 15 is driven, and the corresponding switching valve in the control valve 19 is switched from the neutral position (closed position) to open the oil passage. For this reason, each lever 10
a, 10b, 10c in accordance with the operation of the lift cylinder 2
4. The corresponding one of the reach cylinder 22 and the tilt cylinder 58 is driven.

The hose 5 is connected to the brake valve unit 20.
6 is connected to a hose 59 branched from the cargo pump 1
6 is supplied to the brake valve unit 20 through the hose 59. The brake valve unit 20 and the oil tank 18 are connected through a hose 60.

The pressure switch 48 is connected to the accumulator 6 as an accumulator provided in the brake valve unit 20.
It detects the lower limit value and the upper limit value of the hydraulic pressure (accumulated pressure value) accumulated in 1. When the accumulated pressure value of the accumulator 61 falls below the lower limit value, the controller 41
Is turned off, the pump motor 15 is driven.
When the accumulated pressure reaches the upper limit and the pressure switch 48 is turned on, the driving of the pump motor 15 is stopped. The operation of the left and right auxiliary brake devices 26 and 26 is controlled by the controller 41 controlling the two solenoid valves 51 and 52 of the brake valve unit 20 to excite and demagnetize and control the current value, respectively.

Next, the hydraulic circuit of the brake system will be described with reference to FIG. The brake valve unit 20 includes a pump port P, a tank port T, and two brake ports B1 and B2, for a total of four ports. Pump port P
The hose 59 connected to the cargo handling pump 16 is connected to
Hose 6 connected to oil tank 18 is connected to tank port T
0 is connected. Also, two brake ports B1,
Wheel cylinders 62, 62 of the left and right auxiliary brake devices 26, 26 are connected to B2 through two pipes 27, 27, respectively.

The brake valve unit 20 includes the pressure reducing valve 6
3, check valve 64, electromagnetic on-off valve (shut-off valve) 51, and electromagnetic proportional pressure regulating valve (linear solenoid valve) 52
These valves 51, 52, 63, 64 are arranged in series on an oil passage 65 connecting the pump port P and the brake ports B1, B2. Pressure reducing valve 63 is pump port P
This is to reduce the hydraulic pressure input from. Pressure reducing valve 63
The check valve 64 provided on the oil passage 65 between the valve and the shut-off valve 51 prevents the backflow of the working oil accumulated in the accumulator 61, and the accumulator 61 reaches the set pressure (upper limit). The valve opening pressure is set so as to open the valve up to the maximum. The accumulator 61 and the pressure switch 48 communicate with each other through two oil passages 66 and 67 branched from the oil passage 65 between the check valve 64 and the shut-off valve 51. The discharge port of the linear solenoid valve 52 is connected to the tank port T through an oil passage 68.

The controller 41 includes a shut-off valve 51
And each solenoid 51a, 52 of the linear solenoid valve 52
a. The shut-off valve 51 is
This is an on / off valve that is closed by the urging force of the spring 51b when the solenoid 51a is demagnetized and opens when the solenoid 51a is excited. The output hydraulic pressure (fluid pressure) of the linear solenoid valve 52 is uniquely determined according to the current value input from the controller 41 to the solenoid 52a. Auxiliary brake device 26
Is operated by supplying hydraulic pressure to the wheel cylinder 62, and applies a braking force to the front wheels 5 according to the hydraulic pressure value.

As shown in FIG. 3, the accumulator 61
A pressure vessel 70 having a spherical shape as a vessel is provided. Inside the pressure vessel 70 is a bladder 7 made of a rubber disc spring (leaf spring).
It is divided into two rooms by 1. The side (lower side in the figure) of the two chambers connected to the oil passage (oil pipe) 66 is an oil chamber 72, and the opposite side (the upper side in the figure) is a gas chamber 73, and the gas chamber 73 is a pressure vessel. At the top of 70, plug 7 via O-ring
4 is sealed. When a predetermined amount of pressurized oil is accumulated in the oil chamber 72, the bladder 71 instantaneously elastically deforms from a flat plate state shown by a solid line in FIG. On the other hand, when the accumulated pressure oil is consumed and falls below a predetermined amount, the state returns from the state shown by the dashed line in FIG.
Reduce the volume of

The graph shown in FIG. 4 shows the relationship between the ON / OFF state of the pressure switch and the accumulator pressure (accumulated pressure value). As described above, the bladder 71 has an oil amount (oil pressure).
The accumulator pressure falls below the lower limit in the flat state of the bladder 71 and the pressure switch 48
Is turned off, and after the bladder 71 is deformed into a substantially hemispherical state, the accumulator pressure reaches an upper limit and turns on after the bladder 71 is deformed into a substantially hemispherical state. Due to this hysteresis, the pressure switch 48 is turned off when a predetermined amount of pressure oil is consumed after replenishment of the pressure oil to the accumulator 61, and thereafter is turned on when a predetermined amount of pressure oil is replenished.

When the main brake is applied to the rear wheel 6, the microcomputer 53 determines whether or not the auxiliary brake (auxiliary braking) of the front wheel 5 is necessary, and activates the auxiliary brake device 26 only when it is necessary. It is designed to work. At this time, the solenoid 5 of the linear solenoid valve 52 is determined based on a brake pressure (fluid pressure) determined with reference to a map (not shown).
The current value to be applied to 2a is determined.

In this embodiment, the slip value S, the vehicle speed (initial speed) V, the deceleration β, and the lift H are used as parameters to determine whether or not auxiliary braking is necessary. Find the brake pressure by referring to the map. The vehicle speed V as a parameter indicates an initial speed at the time of a brake operation. When the initial speed V is higher than a certain vehicle speed, auxiliary braking is applied,
At low speed below a certain vehicle speed, no auxiliary braking is applied. The vehicle speed (initial speed) V is obtained by calculating the rotational speeds of the left and right front wheels 5 based on the number of input pulses per unit time from the front wheel rotational speed sensor 28,
It is determined from the average value of the left and right front wheel rotational speeds. Deceleration β
Is calculated by calculating the time change of the vehicle speed V. When the deceleration β during braking is below a certain deceleration, auxiliary braking of the brake pressure corresponding to the deceleration β at that time is applied, No auxiliary braking is applied during deceleration. In the range where the auxiliary braking is applied, for example, when the deceleration β is too large, the brake pressure is reduced, and when the deceleration β is too small, the brake pressure is increased, and the deceleration at that time is obtained so that the appropriate deceleration β is obtained. The brake pressure is adjusted to an appropriate value according to the value of β.

When the slip value S exceeds the threshold value So, it is determined that the slip of the rear wheel 6 is out of the allowable range.
When the slip of the rear wheel 6 is out of the allowable range, the maximum brake pressure (auxiliary braking) is applied except when the initial speed V is in the low speed range and when the deceleration β is in the rapid deceleration range. When the lift H detected by the lift sensor 49 is high, a brake pressure that is smaller by a certain ratio than the brake pressure when the lift is low is selected. This is because the vehicle body is relatively unstable when the load is high and the position of the center of gravity of the vehicle is high at the time of high elevation, and the vehicle body is likely to swing back and forth when suddenly decelerating.

The method of detecting the slip value S of the rear wheel 6 is as follows. The microcomputer 53 obtains the rotation speed of the front wheel 5 based on the number of input pulses per unit time from the front wheel rotation speed sensor 28, and calculates the front wheel vehicle speed (driven wheel conversion vehicle speed) Vf from the front wheel rotation speed and the front wheel radius. . The microcomputer 53
Calculates the rotational speed of the rear wheel 6 based on the number of input pulses per unit time from the rear wheel rotational speed sensor 37, and calculates the rear wheel speed (driving wheel equivalent vehicle speed) Vr from the rear wheel rotational speed and the rear wheel radius.
Is calculated. Here, the forklift 1 is
Since the rotation speed of the front wheel 5 on the turning inner wheel side may become zero near the maximum steering angle where the steering wheel 3 is almost full, the rotation of the front wheel 5 on the turning outer wheel side is detected to obtain the front wheel vehicle speed Vf. Only the input signal from one front wheel speed sensor 28 is used. The microcomputer 53 determines whether the front wheel 5 on the turning outer wheel is left or right based on the steering angle θ input from the steering angle sensor 32. During straight running (θ = 0), only the input signal from one of the left and right front wheel speed sensors 28 is used.

In the present embodiment, the correction coefficient K takes into account that the turning radii of the front wheels 5 and the rear wheels 6 are different when the vehicle turns.
(Θ) (a function of the steering angle θ) is obtained according to the steering angle θ at each time, and the front wheel vehicle speed Vf is multiplied by the correction coefficient K (θ) to convert the front wheel vehicle speed Vf into a vehicle speed corresponding to the rear wheel position. Convert to vehicle speed VR. This vehicle speed VR corresponds to the rear wheel vehicle speed Vr when the rear wheel 6 is not slipping. Then, the controller 41 calculates the difference between the vehicle speed VR and the rear wheel vehicle speed Vr as "slip speed" .DELTA.V (= VR-Vr). In addition,
The threshold value So for determining that the slip of the rear wheel 6 exceeds the allowable range is set to a value near the boundary where the friction coefficient between the rear wheel 6 and the road surface shifts from the static friction region to the dynamic friction region, For example, a value near 0.2 is set in terms of slip ratio. It should be noted that the slip ratio (= (VR-Vr) / VR) may be used in the slip determination instead of the slip speed ΔV.

Further, at the time when the brake operation is detected in order to enhance the responsiveness of the operation of the auxiliary brake device 26, that is, immediately after the input of the braking signal, a predetermined value of the preliminary current such that the hydraulic pressure does not rise in the wheel cylinder 62 is applied to the brake valve The unit 20 (electromagnetic valves 51 and 52) is energized. Specifically, by energizing the solenoid 51a and opening the shut-off valve 51, the hydraulic pressure of the accumulator 61 is applied to the linear solenoid valve 52, and a predetermined current is supplied to the solenoid 52a, so that the linear solenoid valve The spool 52 is previously moved to a position immediately before the valve is opened. The preliminary current value Io supplied to the brake solenoid 52a is a small current slightly smaller than the current value when the spool is located at the boundary between the valve closing and the valve opening.

The microcomputer 53 stores in the memory an auxiliary brake control program for controlling the operation of the auxiliary brake device 26, a disconnection / accumulation abnormality diagnosis routine shown in FIG. 6, an accumulator gas release diagnosis routine shown in FIG. Each program of the pump motor start determination routine shown in FIG.

There are the following types of accumulator abnormalities. (1) Disconnection of Pressure Switch When the signal line of the pressure switch 48 is disconnected, the pressure switch 48 is always turned off, so that the pump motor 15 continues to be driven even after the accumulator 61 completes the pressure accumulation.

(2) Oil Leakage on the Upstream Side of the Accumulator If oil leaks on the upstream side of the accumulator 61, the accumulation of pressure in the accumulator 61 is not completed easily, and the start-up time of the pump motor 15 becomes longer.

(3) Clogging of oil passage If the oil passage 66 is clogged, the oil pressure immediately rises in the oil passage 67 even when the pump motor 15 is started, the pressure switch 48 is turned on, and the accumulation of pressure in the accumulator 61 is completed. The drive of the pump motor 15 stops even though it is not performed.

(4) Clogging of oil passage If the oil passage 67 is clogged, even if the hydraulic pressure of the accumulator 61 rises, it is not transmitted to the pressure switch 48 and the pressure switch 48 remains off, and the accumulator 61
However, the pump motor 15 continues to be driven despite the completion of the accumulation of the pressure.

(5) Accumulator gas release Since the bladder 71 is made of rubber, the bladder 71 has a very slight gas permeability, and even if used normally, a small amount of gas permeates the bladder 71 over a long period of use. Part of the gas then dissolves in the pressure oil. Also, since there is a limit in the seal, a small amount of gas may leak from the stopper during long-term use, and the gas may be reduced. Further, the gas is reduced due to cracks or the like occurring in the bladder 71 and gas dissolving in the pressure oil, or gas leakage due to damage such as opening of a hole in the container. When the gas decreases, even if the pressure switch 48 is turned on, the oil is immediately switched off with the consumption of a small amount of oil, and after the pressure switch 48 is turned off, the pressure is immediately accumulated by replenishing a small amount of oil. I will. Abnormal pressure accumulation due to this kind of outgassing (abnormal replenishment)
When there is, the starting time of the pump motor 15 is shortened, and the starting interval is also shortened.

When the accumulated pressure is normal, the pressure switch 48 is turned on.
Since the startup time of the pump motor 15 due to turning off should be within 1 second, when the startup time exceeds 1 second,
Diagnosis is made as (1), (2) and (4) that the pressure accumulation is abnormal. In addition, when the pressure accumulation is normal, the startup time of the pump motor 15 should be 0.5 seconds or more. Therefore, if the startup time is less than 0.5 seconds, it is diagnosed that the pressure accumulation is abnormal in (3) and (5). Further, in the normal state, even if the auxiliary brake device 26 is operated continuously, the start interval of the pump motor 15 should exceed 4 seconds. Therefore, if the start interval is within 4 seconds, the above-mentioned abnormal pressure accumulation (3) or (5) may occur. Diagnose.

The microcomputer 53 sets the pump motor activation time, which is one of the time information relating to the pressure accumulation operation, to the pressure switch 4.
An OFF counter for measuring (timing) based on the detection signal of No. 8 is built in. The OFF counter measures the time when the pressure switch 48 is off. The microcomputer 53
Incorporates an ON counter for measuring the pump motor activation interval, which is another one of the time information relating to the pressure accumulation operation, based on the detection signal of the pressure switch 48. The ON counter measures (measures) the time when the pressure switch 48 is on. Further, the microcomputer 53 has an accumulator failure flag, and sets the failure flag to "1" when the diagnosis result of the accumulation error is obtained. The accumulator failure flag is reset (cleared) when the forklift is started and the key is turned on.

When the microcomputer 53 obtains the diagnosis result of the pressure accumulation abnormality (failure flag "1"), it ignores the signal of the pressure switch 48 and recognizes that the brake operation has been performed. Start. A program for performing the start control of the pump motor 15 including the forced start control of the pump motor 15 when the result of the accumulated pressure abnormality diagnosis is obtained is a pump motor start determination routine shown in FIG.

The contents of each program shown in FIGS. 6, 8, and 9 will be described below. First, the contents of the disconnection / accumulation abnormality diagnosis routine will be described with reference to the flowchart of FIG.
The accumulator failure flag is reset (cleared) when the forklift is started by turning on the key. First, in step (hereinafter referred to as “S”) 110,
It is determined whether the pressure switch 48 is off. If the pressure switch 48 is off, the process proceeds to S120 and the pressure switch 4
If 8 is not off (that is, if it is on), the process proceeds to S150.

At S120, the OFF counter is incremented. For example, when the pressure switch 48 is switched from on to off, the pump motor 15 is started, and the counting of the starting time is started by the OFF counter.

In the next S130, it is determined whether or not the time count of the OFF counter has exceeded one second. If the counted time does not exceed one second, the routine ends. If the counted time exceeds one second, the process proceeds to S140, and S140
It is determined that the pressure switch is disconnected or the accumulator pressure is abnormal. That is, the starting time of the pump motor 15 is 1
If the time exceeds seconds, a diagnosis result is obtained indicating that any of the above-mentioned (1) disconnection of the pressure switch, (2) oil leakage upstream of the accumulator, and (4) blockage of the oil passage 67.

On the other hand, in S150, it is determined whether or not the time count T (second) of the OFF counter is in the range of 0 <T <0.5. At this time, if it is in the range of 0 <T <0.5, it means that after the pump motor 15 is started, the pressure accumulation is completed so quickly that it cannot occur in a normal state. This corresponds to (3) the clogging of the oil passage or (5) the occurrence of pressure accumulation abnormality due to accumulator gas release. Thus, 0 <T ≦ 0.5
If the measured time T is not within this range, the process proceeds to S180.

In S160, it is determined that the accumulator pressure is abnormal (accumulation of the above (3) and (5)). In S170, the accumulator failure flag is set to "1". That is, when the pressure switch disconnection abnormality (S140) or the accumulator pressure accumulation abnormality (S160) occurs, the failure flag is set to "1".
Is set to

At S180, the OFF counter is cleared. For example, the time T of the OFF counter is 0.5 ≦ T ≦
When it is in the normal range of 1.0, the failure flag is "0"
The OFF counter is cleared as it is. When the disconnection of the pressure switch 48 is diagnosed, the OFF counter stops counting when it reaches a predetermined set value.

Accordingly, as shown in FIG. 5, the start-up of the pump motor 15 obtained by measuring the time from when the pressure switch 48 switches from on to off to when it switches from off to on again is measured. Time t is set time to
If it is within (for example, 1 second), it is determined that the pressure switch 48 is normal (at least not a disconnection). On the other hand, if the activation time t of the pump motor 15 exceeds the set time to (for example, 1 second), a disconnection abnormality of the pressure switch 48,
Alternatively, an oil leak or oil passage 67 upstream of the accumulator
It is determined that the pressure accumulation is abnormal due to the clogging. Further, if the starting time t of the pump motor 15 is shorter than the set time t1 (for example, 0.5 seconds), the accumulator 61
Is diagnosed as a pressure accumulation abnormality such as a gas leak or a blockage of the oil passage 66. Then, the starting time t of the pump motor 15 is changed from the set time t1 (for example, 0.5 seconds) to the set time to (for example, 1 second).
When it is within the range, it is diagnosed that there is no accumulation pressure abnormality.

Next, the contents of the accumulator outgassing diagnosis routine will be described with reference to the flowchart of FIG. S
At 210, the accumulator failure flag is "1"
Is determined. If the failure flag is “1”, the routine is terminated. If not, the next S220
Proceed to.

In S220, the start interval of the pump motor 15 by the pressure switch 48 (that is, not based on the cargo handling operation) is measured. That is, the pressure switch 48
When is turned on, time counting of the ON counter is started, and when the pressure switch 48 is turned off, time counting of the ON counter is stopped.

In S230, it is determined whether or not the start interval is within 4 seconds. If the activation interval is not less than 4 seconds, the accumulator failure flag is set to "0" in S240. On the other hand, if the activation interval is within 4 seconds, S
At 250, the accumulator failure flag is set to "1".

Therefore, as shown in FIG. 7, each time the pressure switch 48 is turned on, the pump motor 1 is kept on.
5, the start time T is counted. If the start interval T of the pump motor 15 exceeds a set time To (for example, 4 seconds), the operation is normal. However, if the start interval T takes a short time equal to or shorter than the set time To, the degassing of the accumulator 61 or the oil passage 66 may occur. Diagnosis of abnormal pressure accumulation such as clogging.

Next, the pump motor start determination routine shown in FIG. 9 will be described. In S310, it is determined whether or not the accumulator failure flag is “1”. If the failure flag is not "1", the process proceeds to S320, and if it is "1", the process proceeds to S350.

In S320, it is determined whether or not the pressure switch 48 is off. If the pressure switch 48 is off, the pump motor is driven in S330. On the other hand, if the pressure switch 48 is not off (if it is on), S34
At 0, the pump motor 15 is stopped.

On the other hand, in S350, it is determined whether or not the brake solenoid 52a is on. If the brake solenoid 52a is on, the pump motor 1 is turned on in S360.
5 is driven. On the other hand, if the brake solenoid 52a is not on, the pump motor 15 is stopped in S370.

Therefore, during traveling of the forklift 1,
For example, even if the brake operation is performed when the rear wheel 6 which is reach-out in the loaded state and the wheel weight is reduced is located on a wet road surface or an icy road surface and the rear wheel 6 slips, it is determined that the rear wheel 6 is almost simultaneously slipped. Auxiliary brake device 26, 2
6, the auxiliary brake is applied to the front wheels 5, 5 whose wheel weights are large, so that the braking distance can be kept short.
Further, a side force acts on the rear wheel 6 deviated leftward from the center of the vehicle width, so that when the vehicle slips, a rearward swinging phenomenon in which the rear portion of the vehicle body flows in the direction of the arrow in FIG.
Is applied in the direction to cancel the turning moment of the vehicle body due to the side force, so that the amount of rear swing at the rear of the vehicle body can be suppressed to be small. Also, when the vehicle speed (initial speed) V during the braking operation is in the high speed range, the auxiliary brake is applied to the front wheel 5, and the brake pressure is appropriately adjusted according to the deceleration β during the braking. For this reason, the braking distance is stabilized regardless of the level of the vehicle speed (initial speed) at the time of the brake operation and the weight of the load. Further, when the load is at a high elevation, a weaker auxiliary brake is applied, so that the vehicle body swings back and forth during braking is suppressed as much as possible.

When the microcomputer 53 determines that the auxiliary brake is necessary and turns on the brake solenoid 52a, that is, when the accumulator pressure accumulation abnormality diagnosis gives the diagnosis result of the accumulation pressure abnormality, that is, the auxiliary brake device 2
When the pump 6 is operated, the pump motor 15 is always driven. For this reason, even if the accumulator 61 has insufficient pressure accumulation due to a pressure accumulation failure caused by a pressure switch failure (disconnection), gas leakage, clogging of an oil passage, etc., the brake valve unit 2 is driven by the pump motor 15.
Since the hydraulic pressure rises to zero, the auxiliary brake device 26 is reliably operated at the instructed brake pressure, and the necessary auxiliary brake for the front wheels 5 is secured.

As described in detail above, according to the present embodiment,
The following effects can be obtained. (1) Time information (activation time and activation interval) relating to the pressure accumulation operation is measured based on a detection signal of the pressure switch 48 originally provided for the purpose of accumulating the pressure of the accumulator 61, and the accumulator 61 is operated based on the time information. Diagnose abnormal pressure accumulation. Therefore, it is not necessary to separately provide sensors dedicated to abnormality diagnosis of the accumulator 61, and therefore, it is possible to cope with only a software change such as addition or change of a program without a hardware design change.

(2) Since it is determined that the pressure accumulation is abnormal when the startup time of the pump motor 15 takes a value that cannot occur when the pump motor 15 is normal, the abnormality of the pressure accumulation can be diagnosed based only on the detection signal of the pressure switch 48. In particular, to
A disconnection abnormality of the pressure switch 48 can be diagnosed by a diagnosis method in which a pressure accumulation abnormality is determined when the activation time that always ends within seconds (for example, one second) exceeds to seconds. In addition to the disconnection abnormality, it is also possible to diagnose a pressure accumulation abnormality caused by oil leakage on the upstream pipe of the accumulator 61.

(3) When the pressure accumulation is normal, t1 seconds (for example, 0.
If the start-up time, which should be 5 seconds or longer, is abnormally short, less than t1 second, a pressure accumulation abnormality can be diagnosed by a diagnosis method for determining a pressure accumulation abnormality.

(4) Since it is determined that the pressure accumulation is abnormal when the start interval of the pump motor 15 takes a value that cannot occur in a normal state, the abnormality of the pressure accumulation can be diagnosed based only on the detection signal of the pressure switch 48. For example, when pressure accumulation is normal, To
Pump motor 15 which should take more than 2 seconds (for example, 4 seconds)
When the start interval of the engine is short, which is shorter than To seconds, it is possible to diagnose the clogging of the oil passage 66 and the abnormality of the accumulator gas escape by the diagnosis method of determining the pressure accumulation abnormality.

(5) When the accumulated pressure abnormality diagnosis result is obtained, a control method of always operating the pump motor 15 when the auxiliary brake device 26 is operated is adopted.
Even when such a pressure accumulation abnormality occurs, an appropriate auxiliary brake can be reliably applied to the front wheel 5 when necessary. For this reason,
Even in the event of a pressure accumulation abnormality, good braking characteristics are maintained.

(6) Since the pressure is accumulated in the accumulator 61 each time the pump motor (loading motor) 15 is driven by the cargo handling operation, the frequency of driving the pump motor 15 only for the purpose of accumulating the accumulator 61 can be reduced. , And can contribute to the power saving of the battery 3. Moreover, the auxiliary brake device 2
Since the pump motor 15 and the cargo handling pump (hydraulic pump) 16 are shared between the mast unit 6 and the mast device 21, it is not necessary to provide a dedicated electric motor and a hydraulic pump, respectively, and the space for storing parts can be reduced. Can be. Therefore, disadvantages such as an increase in the size of the forklift 1 and a reduction in the degree of freedom in layout are hardly caused.

(7) Since the accumulator 61 is used as the hydraulic pressure source of the brake valve unit 20, a delay in the rise of the hydraulic pressure at the start of the electric motor, which is problematic in a system in which the hydraulic pump driven by the pump motor is directly used as the hydraulic pressure source. The operation responsiveness of the auxiliary brake devices 26, 26 can be improved without concern. In particular, by pre-energizing the solenoid valves 51 and 52 of the brake valve unit 20,
Since the operation responsiveness of the auxiliary brake device 26 is enhanced,
The braking distance can be shortened more effectively.

The embodiment is not limited to the above, and may be implemented, for example, in the following manner. The method of obtaining the time information regarding the pressure accumulation operation is not limited to the method using the signal of the pressure switch 48. For example, since the microcomputer 53 knows the operation state of the pump motor 15 from the state of the command signal, the microcomputer 53 may obtain time information on the operation of the pump motor 15 based on the command signal.
If the pump motor 15 has a built-in motor rotation detector or the like, a method of obtaining time information based on a motor rotation detection signal from the motor rotation detector may be used. Further, the sensor for managing the accumulated pressure of the accumulator 61 may be a pressure sensor instead of the pressure switch.

In the disconnection / accumulation abnormality diagnosis routine shown in FIG. 6, the abnormality diagnosis processing for diagnosing an abnormality when the activation time is too short is different from the accumulator gas leakage diagnosis routine shown in FIG. Since the diagnosis is performed only by the method described above, the reliability of the diagnosis may be slightly lowered, but it is also possible to adopt only one of them. For example, only the disconnection / accumulation abnormality diagnosis routine shown in FIG.
150 and 160) and an accumulator outgassing diagnosis routine (FIG. 8). Further, at least one selected from the plurality of types of pressure accumulation abnormalities described in the above embodiment may be diagnosed. For example, only a disconnection abnormality may be diagnosed. In addition, only the outgassing abnormality may be diagnosed. Further, in the above embodiment, 1
In the case of diagnosing two accumulator abnormalities by two different methods, the reliability of the diagnosis is improved by adopting a configuration in which the failure flag is set to "1" only when both accumulator abnormalities are diagnosed. You may.

In the case of a pressure accumulation abnormality in which the pressure accumulation function of the accumulator 61 itself is kept normal, such as when the pressure switch 48 fails, it is not always necessary to operate the pump motor 15 when the auxiliary brake device 26 operates. That is, after the disconnection is determined in S140 in the flowchart of FIG.
The process proceeds to 180, and the process is performed such that the failure flag is not set to “1” at the time of disconnection determination. In this case, the pump motor 15 is actuated every time a cargo handling operation is performed, and the accumulator 61 is frequently accumulated pressure. In most cases, the accumulator 61 is maintained in the accumulated pressure state exceeding the lower limit, so that the auxiliary brake device 26 operates normally. Is done. Further, if the pump motor 15 is operated every time the auxiliary brake device 26 is operated under the condition that the accumulation of pressure is diagnosed, the motor operation noise is annoying to the driver, but the pressure switch 48 is broken (abnormal disconnection). In this case, at least the generation of such annoying motor operation noise can be avoided. It should be noted that even if the effect of the auxiliary brake by the auxiliary brake device 26 is somewhat weakened, the main brake operates normally, and although the effect of shortening the braking distance is slightly suppressed, there is no particular problem in the braking function of the forklift.

The on / off of the pressure switch 48 for driving the pump motor may be reversed from that of the above embodiment, and the pump motor 15 may be driven when the pressure switch 48 is on. In this case, the pressure accumulation abnormality can be diagnosed similarly, and a short circuit can be diagnosed instead of disconnection of the signal line of the pressure switch.

In the above-described embodiment, the control for operating the pump motor 15 when the hydraulic braking device (auxiliary braking device) 26 is operated under the condition that the diagnosis result of the pressure accumulation abnormality is given is based on the recognition of the microcomputer. On the other hand, for example, an electric circuit that operates based on the detection signal of the brake switch 36 when the brake pedal 35 is operated by the brake is separately provided, and the electric circuit is operated based on the detection signal of the brake switch 36 every time the brake is operated. A configuration in which the pump motor 15 is actuated via the pump can also be adopted. Also in this case, the electric motor 15 can be always operated when the auxiliary brake device 26 is operated.

In the above embodiment, under the condition that the diagnosis result is abnormal, the pump motor 15 is operated when the hydraulic brake device (auxiliary brake device) 26 is operated so that the auxiliary brake is normally operated. However, this measure is not always necessary, and a configuration in which only the abnormality diagnosis is performed may be adopted. In addition, when it is diagnosed as abnormal, a warning sound or a warning lamp notifies the driver of the abnormality.

The time information is not limited to the start time or the start interval. As the time information, for example, the time from the start to the next start can be measured, or the time from the start to the stop of the next start can be measured. In this case, since the start-up time and the start-up interval are totaled, the pressure accumulation abnormality can be diagnosed, though somewhat less reliable than the method of diagnosing them individually. In this method or the method of the embodiment, in order to increase the reliability of the abnormality diagnosis, a method of diagnosing the abnormality only when the same type of abnormality is detected a plurality of times may be adopted.

The parameters for determining the necessity of the auxiliary brake are not limited to the above embodiment. The brake pressure may be set using any one or more of the following four parameters: slip value, vehicle speed (initial speed), deceleration β, and lift. However, it is preferable that one of the parameters includes the slip value. By setting the load as a parameter instead of the deceleration β and determining the brake pressure in accordance with the load, it is possible to employ auxiliary braking control that can always obtain an appropriate deceleration without being affected by the load. Further, the control may be such that the auxiliary braking is applied only at the time of relatively rapid braking with a large braking operation amount. Further, the brake pressure for applying the auxiliary braking may always be a constant value regardless of the parameter.

The hydraulic brake device (hydraulic brake device) is not limited to an auxiliary brake device.
For example, it may be a main brake device for braking drive wheels. In this case, a configuration without the auxiliary brake device or a configuration in which accumulators serving as hydraulic pressure sources for the auxiliary brake device and the main brake device are individually provided may be used.

In the case of a hydraulic brake device using a pressure accumulator as a hydraulic source, the pressure regulating valve for braking need not be an electromagnetic valve. The present invention is also applicable to a configuration in which the pressure control valve is mechanically operated by a brake operation.

The hydraulic pressure source for supplying the pressure oil to the brake valve unit is not limited to the loading pump 15. For example, a dedicated pump and an electric motor dedicated to the brake valve unit may be used. Also in this case, the accumulated pressure abnormality diagnosis can be performed based on the detection signal of the pressure switch 48.

The means for accumulating pressure for accumulating pressure oil in the accumulator is not limited to the electric motor and the hydraulic pump.
For example, when the industrial vehicle is an engine vehicle, an electromagnetic switching valve (open / close valve) interposed on an oil passage between the hydraulic pump and the accumulator to supply pressure oil supplied from a hydraulic pump driven by the engine to the accumulator. ).

The fluid to be stored is not limited to pressurized oil. For example, the present invention can also be applied to diagnosis of a gas pressure accumulation abnormality. The replenishing device is not limited to a container that accumulates pressure, and replenishes the liquid when a sensor (for example, a liquid level sensor) detects that the amount of liquid in the container has decreased in a container that accumulates liquid such as hydraulic oil or water. Can also be applied. Further, the method of using the fluid in the container is not particularly limited to the purpose of driving a hydraulic drive device such as a hydraulic brake device, and for example, a cleaning device that injects a cleaning liquid (water or the like) or a gas (air or the like). The fluid itself may be used as in the case of, for example, and a replenishment abnormality diagnosing device can be applied to this type of replenishing device.

The hydraulic drive device is not limited to a hydraulic brake device. For example, a hydraulic clutch device operated for disengaging the clutch may be used. In this case, the clutch device may be a clutch device provided for switching the engine type industrial vehicle between forward and backward, or a clutch device of a differential device with a differential limiting function for performing a differential operation of the left and right wheels.

The industrial vehicle is a reach-type forklift 1
However, the present invention is not limited to this, and can be applied to other types of forklifts such as a counterbalance type and an order picking type. It can also be applied to unmanned forklifts. In addition, the present invention can be applied to industrial vehicles other than forklifts.

The technical ideas other than the claims that can be grasped from the embodiment and the like will be described below. (1) In any one of claims 2 to 4, the abnormality diagnosis means diagnoses an abnormality relating to the pressure accumulator when the time information takes a value that cannot occur during normal pressure accumulation.

(2) The time information measured by the abnormality diagnosing means according to any one of claims 2 to 4, wherein the time information indicates that the accumulated pressure value of the accumulator has reached an upper limit value after the start of the accumulating operation. This is the pressure accumulation operation time until the pressure accumulation operation stops.

(3) In any one of claims 4 to 10, the judging means detects a slip of a wheel to which a braking force is applied by the main braking means, and if the slip is detected, auxiliary braking is required. A storage pressure abnormality diagnosis device for an industrial vehicle that determines that there is a storage pressure abnormality.

(4) In any one of the technical ideas of claims 4 to 9 to (3), the driving wheel to which the braking force by the main braking means is applied may be a vehicle among front wheels and rear wheels. The wheel on the side where the wheel load becomes smaller as the loading load of the cargo handling device mounted on the vehicle is larger, and the wheel to which the auxiliary braking force is applied by the auxiliary braking means, A storage pressure abnormality diagnosis device for an industrial vehicle that is a wheel on the side where the weight increases.

[0112]

As described above in detail, according to the first aspect of the present invention, a replenishment abnormality such as a case where the container is not normally refilled or a case where the replenishment operation is continued even though the container is already replenished is compared. The diagnosis can be made with a simple configuration.

According to the inventions described in claims 2 to 10, a relatively simple structure for accumulating pressure abnormality such as normal accumulation of pressure in the accumulator or continuous operation of accumulating pressure even though the accumulator has already been accumulated. Can be diagnosed.

According to the present invention, if it is determined that the auxiliary braking is necessary at the time of braking, the auxiliary braking is applied to the wheel on the opposite side of the front and rear wheels from the main braking wheel. Can be kept short. In addition, because it is possible to diagnose the accumulation of pressure in the accumulator, which is the hydraulic pressure source of the hydraulic braking device, measures such as performing the pressure accumulation operation when the hydraulic braking device is activated, such as applying auxiliary braking even when the accumulation of pressure abnormality occurs, are taken. It becomes possible to hit.

According to the eleventh aspect of the present invention, even when it is diagnosed that the replenishing device is abnormal, the fluid is supplied to the container when the operating device is operated, so that the operating device can be operated almost normally. .

According to the twelfth aspect of the present invention, even when it is diagnosed that there is an abnormality related to the accumulator, the hydraulic oil is supplied to the accumulator when the hydraulic drive is in operation. It can be operated almost normally.

According to the thirteenth aspect of the present invention, even when it is determined that there is an abnormality related to the pressure accumulator, it is determined that the braking of the drive wheels needs to be assisted, Since the pressure oil is supplied to the pressure accumulator, the hydraulic braking device can be operated almost normally, and auxiliary braking can be applied to the drive wheels and the wheels on the front and rear opposite sides.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a forklift according to an embodiment.

FIG. 2 is a hydraulic circuit diagram of a brake system.

FIG. 3 is a schematic sectional view of an accumulator.

FIG. 4 is a graph showing a relationship between a pressure switch and an accumulator pressure.

FIG. 5 is a graph illustrating a method of diagnosing a pressure accumulation abnormality.

FIG. 6 is a flowchart of a disconnection / accumulation pressure abnormality diagnosis routine.

FIG. 7 is a graph for explaining a method of diagnosing a pressure accumulation abnormality.

FIG. 8 is a flowchart of an accumulator outgassing diagnosis routine.

FIG. 9 is a flowchart of a pump motor activation determination routine.

FIG. 10 is a side view of a forklift.

FIG. 11 is a plan sectional view of a forklift.

[Description of Signs] 1 ... Reach type forklift truck as an industrial vehicle, 5 ... Front wheel, 6 ... Rear wheel (drive wheel), 11 ... Accelerator lever, 14 ... Traveling motor constituting main braking means, 15
.. A pump motor (loading motor) as an electric motor, constituting a replenishing means, a replenishing device and a pressure accumulating means; 16 a cargo pump as a hydraulic pump, constituting a replenishing means, a replenishing device and a pressure accumulating means;
0: a brake valve unit constituting a braking control means;
21: a mast device as a cargo handling device, 26: an auxiliary brake device as a hydraulic drive device and a hydraulic brake device,
28: a front wheel rotation speed sensor forming a determination means; 32, a steering angle sensor forming a determination means; 33, a main brake device as a main braking means; 35, a brake pedal; 36, a rotation speed sensor forming a determination means; 41: a controller serving as an abnormality diagnosis means, a pressure accumulation control means and a control means, constituting a braking control means; 48, a pressure switch serving as a sensor and a pressure accumulation detector; 49, a lift sensor constituting a judgment means; Valves, 52 ... linear solenoid valves, 52a ... solenoids, 53 ..., microcomputers constituting brake control means, determination means and pressure accumulation control means, and motors constituting abnormality diagnosis means, 54 ... motor pressure accumulation control means and main braking means Circuit, 61: an accumulator that constitutes a replenishing device and serves as a container and an accumulator.

Claims (13)

[Claims] When the sensor detects that the fluid amount or the fluid pressure in the container falls below the lower limit value, the replenishing means is operated so as to increase the fluid amount or the fluid pressure in the container, and replenishment is performed.
In a replenishing device that stops the replenishment operation when the sensor detects that the amount of fluid or the fluid pressure in the container reaches the upper limit value, information on the time of the replenishment operation is measured based on the detection signal of the sensor, If the information on the time takes a value that cannot occur when the replenishing device is normal, the replenishing abnormality diagnostic device for an industrial vehicle includes an abnormality diagnosing means for diagnosing the replenishing device as abnormal. 2. A hydraulic drive device provided in an industrial vehicle, a pressure accumulator serving as a hydraulic pressure source of the hydraulic drive device, and a pressure accumulation detection for detecting whether a required amount of pressure oil is accumulated in the pressure accumulator. A pressure accumulating operation unit that performs a pressure accumulating operation for supplying pressurized oil to the pressure accumulator; and when the pressure accumulation detector detects that the accumulated pressure value of the pressure accumulator has fallen below a lower limit, the pressure accumulating operation unit. Accumulation control means for operating to perform a pressure accumulation operation for supplying pressure oil to the pressure accumulator, and stopping the pressure accumulation operation when it is detected by the pressure accumulation detector that the accumulated pressure value of the accumulator has reached an upper limit value, An accumulator abnormality diagnosis device for an industrial vehicle, comprising: abnormality information diagnosing means for measuring time information relating to the pressure accumulation operation of the pressure accumulation operation means and diagnosing an abnormality relating to the pressure accumulator based on the time information. 3. The storage pressure abnormality diagnosis device for an industrial vehicle according to claim 2, wherein the hydraulic drive device is a hydraulic brake device provided for braking an industrial vehicle. 4. A determining means for determining whether or not it is necessary to assist braking of a driving wheel when a main braking means for braking a front wheel or a rear wheel which is a driving wheel is actuated; A hydraulic braking device for applying an auxiliary braking force to the opposite wheel, a pressure accumulator serving as a hydraulic oil pressure source for operating the hydraulic braking device, and braking assistance is required by the determination means. Once determined,
Brake control means for supplying hydraulic pressure to the pressure accumulator to perform hydraulic control for operating the hydraulic braking device; pressure accumulator for detecting a pressure value of the pressure accumulator; and supplying pressure oil to the pressure accumulator. Pressure accumulating means for accumulating pressure, and when the accumulator detects that the accumulated pressure value of the accumulator has fallen below a lower limit, the accumulator is actuated to supply pressure oil to the accumulator. A pressure accumulating control means for causing the pressure accumulating operation to stop the accumulating operation when the accumulated pressure value of the accumulator reaches the upper limit value by the accumulator, and measuring time information on the accumulating operation of the accumulating means. And an abnormality diagnosing device for diagnosing an abnormality relating to the accumulator based on the time information. 5. The time information measured by the abnormality diagnosing means is a pressure accumulation operation time from when the pressure accumulation operation is started to when the accumulated pressure value of the accumulator reaches an upper limit value and stops. The means diagnoses that there is an abnormality relating to the pressure accumulator when the pressure accumulating operation time of the pressure accumulator exceeds a set time set to a value equal to or longer than the maximum required time in a normal state. A storage pressure abnormality diagnosis device for an industrial vehicle according to the above paragraph. 6. The time information measured by the abnormality diagnosing means is a pressure accumulating operation time from when the accumulating operation is started to when the accumulating value of the accumulator reaches an upper limit value and stops. The means for diagnosing an abnormality relating to the pressure accumulator when the pressure accumulating operation time of the pressure accumulator is shorter than a set time set to a value equal to or less than a minimum required time in a normal state. A storage pressure abnormality diagnosis device for an industrial vehicle according to claim 1. 7. The time information measured by the abnormality diagnosing means is a start interval of a pressure accumulating operation of the accumulator, and the abnormality diagnosing means is configured to operate the hydraulic drive device or the hydraulic brake device continuously. The storage pressure abnormality diagnosis for an industrial vehicle according to any one of claims 2 to 4, wherein when an activation interval shorter than a set time interval that cannot occur in a normal state is detected, an abnormality relating to the pressure accumulator is diagnosed. apparatus. 8. The industrial vehicle according to claim 2, wherein the abnormality diagnosing unit measures time information relating to the pressure accumulation operation of the pressure accumulation operation unit based on a detection signal of the pressure accumulation detector. Storage pressure abnormality diagnosis device. 9. The pressure accumulating means comprises an electric motor, and a hydraulic pump driven by the electric motor and connected to the accumulator through an oil passage.
The storage pressure abnormality diagnosis device for an industrial vehicle according to any one of claims 1 to 8. 10. An industrial vehicle according to claim 1, wherein the drive wheels to which the braking force by the main braking means is applied are rear wheels, and the wheels to which the auxiliary braking force by the hydraulic braking device are applied are front wheels. The storage pressure abnormality diagnostic device for an industrial vehicle according to any one of claims 4 to 9, wherein the device is a reach-type forklift mounted on a front side of the vehicle body so as to be movable back and forth. 11. A replenishment abnormality diagnosing device according to claim 1, and an operating device operated by a fluid in the container, wherein when the abnormality diagnosing means diagnoses that there is an abnormality in the replenishing device. A fluid-type operation control device for an industrial vehicle, further comprising control means for operating the replenishing device when it recognizes that the operating device is operating. 12. An accumulator abnormality diagnosing device according to any one of claims 2 to 9, wherein when the abnormality diagnosing means diagnoses that there is an abnormality relating to the accumulator, the hydraulic drive device A hydraulic operation control device for an industrial vehicle, comprising: control means for operating the pressure accumulating operation means when recognizing that it is operating. 13. An accumulator abnormality diagnosing device according to any one of claims 4 to 10, wherein when the abnormality diagnosing unit diagnoses that there is an abnormality relating to the accumulator, a drive wheel is judged by the judging unit. When the hydraulic braking device is actuated by the braking control means when it is determined that it is necessary to assist braking, the pressure accumulating operation means is operated to perform a pressure accumulating operation for supplying pressure oil to the accumulator. Brake control device in an industrial vehicle provided with means.