TWI634067B - Industrial vehicles - Google Patents

Abstract

The pressure storage state of the pressure accumulator is well maintained.

The cargo loading / unloading circuit 41 is provided with a center-closed control valve. The pressure compensation circuit 43 has a pressure compensation valve 66 on an oil passage 65 connecting the hydraulic pump 31 and the oil tank 33. When the cargo handling device is not in operation, it is necessary to accumulate the pressure of the accumulator 60 provided in the brake circuit 42 as the hydraulic pressure source for the auxiliary braking devices 50 and 51, and to provide a pressure compensation valve 66 to lock the oil passage 65 The hydraulic load pump 31 is driven by controlling the cargo loading motor 30. As a result, the hydraulic system generated in the hydraulic pump 31 is not released to the oil groove 33 through the oil passage 65, and an oil pressure for generating pressure in the accumulator 60 is generated in the oil passage 53.

Description

Industrial vehicles

The invention relates to an industrial vehicle having a hydraulic brake device and a hydraulic cargo handling device.

As an industrial vehicle provided with a hydraulic actuator, for example, a stacker is known (for example, refer to patent document 1). In the stacker of Patent Document 1, the pressure for operating the hydraulic actuator is stored in an accumulator, and the actuator is released by releasing the pressure. Further, in the hydraulic mechanism of the stacker of Patent Document 1, an open center control valve that communicates between the hydraulic pump and the oil tank is adopted when the operation of the cargo handling device is not instructed. Even when the cargo loading and unloading device is not instructed to operate, the hydraulic pump can be driven to accumulate pressure toward the accumulator.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-114499

Recently, in order to reduce the size of the cargo handling equipment, It is considered that the hydraulic pressure mechanism adopts a closed center control valve to construct the hydraulic pressure mechanism in a state where no cargo is loaded and when a cargo with a maximum loading weight is loaded. The center position closed-circuit control valve is a structure in which the hydraulic pump and the cargo loading and unloading device are not connected when the operation of the cargo loading and unloading device is not instructed. In addition, the hydraulic mechanism using a neutral closed-loop control valve includes a pressure compensation valve. The pressure compensation valve system compensates the dynamic pressure of the hydraulic cylinder that makes the cargo loading and unloading device act, and releases the pressure toward the oil tank when the pressure in the circuit exceeds the relief pressure. Therefore, in a hydraulic mechanism using a center-position closed-circuit control valve, even if the hydraulic pump is driven when the cargo loading and unloading device is not instructed to operate, the pressure in the circuit is still released to the oil tank via the pressure compensation valve, so it cannot The accumulator accumulates pressure. Therefore, it is necessary to review the structure for accumulating the pressure of the accumulator with respect to the oil pressure mechanism using a neutral closed-loop control valve.

The present invention has been made in view of the problems in the prior art, and an object of the present invention is to provide an industrial vehicle that can maintain the pressure storage state of the pressure accumulator well.

The industrial vehicle system structure that solves the above-mentioned problems is an industrial vehicle including a hydraulic brake device and a hydraulic cargo handling device, which includes a first hydraulic circuit and a reservoir serving as a hydraulic source of the brake device. Pressure device and detection means for detecting the pressure storage state of the pressure accumulator; the first oil circuit is connected to the aforementioned first hydraulic circuit and the hydraulic pump; and the second oil circuit has means for loading and unloading the cargo. When not in operation, the hydraulic pump and the cargo loading and unloading device are set to a non-connected middle position closed-circuit control valve, and the control valve is used to switch the supply and discharge of the hydraulic oil so as to make the front The cargo loading and unloading device is driven; the second oil circuit is connected to the aforementioned second hydraulic circuit and the aforementioned hydraulic pump; the pressure compensation circuit is provided to be connected to the aforementioned hydraulic pump and oil tank without passing through the aforementioned second hydraulic circuit. A pressure compensating valve on a third oil path, and an applying mechanism for applying a force to lock the third oil path to the pressure compensating valve; and a control device, wherein the control device determines that it is necessary to cause the pressure compensation valve based on a detection result of the detection means. When the accumulator accumulates pressure, the aforementioned applying mechanism is actuated and the electric motor is controlled to drive the hydraulic pump, and the force that locks the third oil path is applied to the pressure compensation valve by the actuation of the applying mechanism. An oil pressure is generated on the oil path to accumulate the pressure of the accumulator.

According to this configuration, when it is necessary to accumulate the pressure of the accumulator, a force is applied to the pressure compensation valve to actuate the applying mechanism to close the third oil passage. Therefore, the hydraulic pressure generated by the driving of the hydraulic pump is not released to the oil tank by the pressure compensation valve. As a result, a hydraulic pressure is generated in the first oil passage connecting the hydraulic pump to the first hydraulic circuit including the pressure accumulator, and the pressure accumulator can be stored by the hydraulic pressure. Therefore, the pressure storage state of the pressure accumulator can be favorably maintained.

In the above industrial vehicle, the pressure compensation valve has a pressure receiving portion that receives the oil pressure of the third oil path, the imparting mechanism includes a solenoid, and a movable portion that is movable by a magnetic force of the solenoid. The pressure receiving portion of the pressure compensating valve receives a force from the movable portion to open the third oil passage. According to this configuration, the providing mechanism can be miniaturized.

In the above industrial vehicle, the first hydraulic circuit may further include a check valve that maintains a pressure stored in the pressure accumulator. According to this configuration, the pressure accumulation state of the pressure accumulator can be appropriately maintained.

In the above industrial vehicle, the control device may stop the operation of the application mechanism and stop the electric motor when the accumulator is stored at a predetermined pressure. According to this configuration, when the accumulator is stored at a predetermined pressure, by stopping the motor, it is possible to suppress power consumption that is more than necessary.

In the above industrial vehicle, the cargo loading and unloading device may have a plurality of hydraulic actuating devices, and the control device may detect the operation of the hydraulic pressure actuating device when the cargo loading and unloading device is operated, and adjust the power given by the granting mechanism. The force for locking the third oil path is used to set the relief pressure of the pressure compensation valve corresponding to the hydraulic actuator. According to this configuration, the relief pressure corresponding to the hydraulic actuator can be set.

In the aforementioned industrial vehicle, the brake device may be a front wheel brake device of a telescopic stacker.

According to the present invention, the pressure storage state of the pressure accumulator can be favorably maintained.

10‧‧‧ Stacker (industrial vehicle)

21‧‧‧Cargo handling device

30‧‧‧Motor (motor) for cargo handling

31‧‧‧Hydraulic Pump

34‧‧‧oil path (second oil path)

36‧‧‧controller (control device)

41‧‧‧Cargo handling circuit (second hydraulic circuit)

42‧‧‧Brake circuit (first hydraulic circuit)

43‧‧‧Pressure compensation circuit

45, 47, 49‧‧‧ control valves

50、51‧‧‧Auxiliary brake device (brake device, front wheel brake device)

53‧‧‧oil path (first oil path)

56‧‧‧Check valve

60‧‧‧pressure accumulator

63‧‧‧Switch (detection means)

65‧‧‧oil path (third oil path)

66‧‧‧Pressure compensation valve

66a‧‧‧Valve body (pressure receiving part)

68‧‧‧ Empowerment Agency

68a‧‧‧solenoid

68b‧‧‧movable section

FIG. 1 is a schematic side view showing a stacker.

Fig. 2 is a schematic diagram illustrating a hydraulic mechanism.

Figure 3 is a hydraulic circuit diagram illustrating the pressure compensation circuit and the brake circuit.

4 (a) and 4 (b) are schematic diagrams illustrating the operation of the pressure compensation valve.

FIG. 5 is an explanatory diagram showing changes in a pressure storage state of the pressure accumulator.

Hereinafter, an embodiment of an industrial vehicle will be described with reference to FIGS. 1 to 5.

The stacker 10 as an industrial vehicle shown in FIG. 1 is a three-wheeled vehicle with two front-wheel driven and one-wheel driven vehicles. Reach type Forklift. A pair of left and right telescopic legs 13 extend forward from the vehicle body 11, and left and right front wheels 14 are rotatably supported at the front ends of the respective telescopic tracks constituting the left and right telescopic legs 13. The rear wheel 15 is the driving wheel of the steering wheel. It is offset to the left in the width direction of the vehicle. On its right side, auxiliary wheels (casters) are provided at positions deviating from a predetermined distance.

The rear part of the vehicle body 11 is a standing type cab 16 and an installation panel 17 on the front side of the cab 16 is provided with a cargo handling lever 18 or a forward and backward operation as a cargo handling operation means for cargo handling operations Used accelerator joystick 19. A steering wheel 20 is provided in the cab 16.

The front side of the vehicle body 11 is equipped with a hydraulic cargo handling device (mast device) 21. The cargo handling device 21 includes a two-stage mast 22 and a fork 23. The vehicle body 11 is provided with a plurality of hydraulic cylinders for causing the cargo handling device 21 to perform a predetermined operation. The hydraulic cylinder includes: a lifting cylinder 24 that moves the mast 22 in the up and down direction; a telescopic cylinder 25 that moves the mast 22 in the forward and backward direction within a predetermined stroke range; and an inclined cylinder 26 (shown in the figure) that tilts the mast 22 in the front and rear direction 2).

As shown in FIG. 2, the vehicle body 11 is provided with a cargo loading / unloading motor 30 which is a motor serving as a driving source of the cargo loading / unloading operation; A hydraulic pump 31 driven by a motor 30; and a hydraulic mechanism 32 to which working oil discharged from the hydraulic pump 31 is supplied. The oil pressure mechanism 32 controls the supply and discharge of the working oil to the cylinders 24, 25, and 26. An oil passage 34 is connected to the hydraulic pump 31 to supply the operating oil drawn from the oil tank 33 to the hydraulic mechanism 32. The oil passage 34 is connected to a discharge port of the hydraulic pump 31. An oil passage 35 is connected to the hydraulic mechanism 32 to allow the working oil discharged to the oil tank 33 to pass therethrough.

The vehicle body 11 is provided with a controller 36 as a control device. The controller 36 controls the driving of the hydraulic pump 31 by controlling the start and stop of the cargo loading / unloading motor 30. In addition, a sensor is electrically connected to the controller 36 for detecting an operation state of the cargo loading / unloading lever 18. The sensor includes: a lift sensor 37 that detects the operating state of the lift lever 18a; a telescopic sensor 38 that detects the operating state of the retractable lever 18b; and a tilt that detects the operating state of the tilt lever 18c Ensor 39. The raising / lowering joystick 18a instructs a raising / lowering operation (up-and-down movement of the mast 22). The telescopic joystick 18b instructs telescopic movement (forward and backward movement of the mast 22). The tilt lever 18c instructs a tilt action (tilt action of the mast 22). An accelerator sensor 40 is electrically connected to the controller 36 to detect an operation amount (accelerator opening degree) of the accelerator lever 19.

Hereinafter, the configuration of the hydraulic mechanism 32 will be described in detail.

The hydraulic mechanism 32 includes a cargo loading and unloading circuit 41 as a second hydraulic circuit, a brake system circuit 42 as a first hydraulic circuit, and a pressure compensation circuit 43.

The cargo handling system 41 is an oil pressure circuit that controls the hydraulic pressure for driving the cargo handling device 21. The cargo loading / unloading circuit 41 includes a control valve for lifting operation of an oil chamber connected to the lifting cylinder 24 via an oil passage 44. 45; a control valve 47 for telescopic operation of the oil chamber connected to the telescopic cylinder 25 via the oil passage 46; and a control valve 49 for tilting operation of the oil chamber connected to the tilt cylinder 26 via the oil passage 48. Each of the control valves 45, 47, and 49 is connected to an oil passage 34 connected to the hydraulic pump 31 and an oil passage 35 connected to the oil tank 33, respectively. The oil passage 34 functions as a second oil passage connecting the hydraulic pump 31 and the cargo handling system 41.

The control valve 45 is mechanically connected with a lifting lever 18a, and the opening and closing state of the control valve 45 is switched by the operation of the lifting lever 18a. A telescopic joystick 18b is mechanically connected to the control valve 47, and the opening and closing state of the control valve 47 is switched by the operation of the telescopic joystick 18b. A tilt lever 18c is mechanically connected to the control valve 49, and the opening and closing state of the control valve 49 is switched by the operation of the tilt lever 18c.

Each of the control valves 45, 47, and 49 in this embodiment sets the hydraulic pump 31 and the cargo loading and unloading device 21 as non-connected, closed-position switching valves when all the cargo handling levers 18 are not operated. Further, in the cargo loading / unloading system 41, when the cargo loading / unloading lever 18 is operated, the supply / discharge of the oil pressure from the hydraulic pump 31 is switched by the respective control valves 45, 47, 49, and the cargo loading / unloading device 21 drive. For example, when the telescopic joystick 18 b is operated, the hydraulic oil from the hydraulic pump 31 is supplied to the oil chamber of the telescopic cylinder 25 through the oil passage 46 connected to the control valve 47.

The brake circuit 42 is a hydraulic circuit that controls the hydraulic pressure of the auxiliary brake devices 50 and 51 (shown in FIG. 3) that are hydraulic brake devices mounted on the left and right front wheels 14. In addition, the stacker 10 is provided with a main brake device (not shown) different from the auxiliary brake devices 50 and 51. The main brake device is used to give braking force to the rear wheel 15 and the rear wheel brake device. The vehicle devices 50 and 51 are front wheel brake devices that give the front wheels 14 a braking force. In the stacker 10, when the braking force based on the main braking device is applied to the rear wheels 15, it is determined whether a braking force based on the auxiliary braking devices 50, 51 is required, and the auxiliary braking devices 50, 51 are actuated when necessary. The pressure compensation circuit 43 is a circuit that controls the hydraulic pressure in the hydraulic mechanism 32.

Hereinafter, the configurations of the brake system circuit 42 and the pressure compensation circuit 43 will be described in detail with reference to FIG. 3.

The brake system circuit 42 will be described.

The brake system circuit 42 has an oil path 53 connected to the auxiliary brake devices 50 and 51. The oil passage 53 is connected to the hydraulic pump 31 and functions as a first oil passage that connects the hydraulic pump 31 and the brake system circuit 42. The oil passage 53 includes a pressure reducing valve 54, a filter 55, a check valve 56, a filter 57, a switching valve 58, and a pressure reducing valve 59 in this order from a side close to the hydraulic pump 31. An accumulator 60 is connected to the oil passage 53 on the downstream side of the check valve 56. The pressure accumulator 60 accumulates the hydraulic pressure source of the auxiliary brake devices 50 and 51 and the hydraulic pressure for operating the auxiliary brake devices 50 and 51. A drain valve 61 is connected to the oil passage 53 at a position downstream of the connection portion of the accumulator 60. The pressure reducing valves 54 and 59 and the relief valve 61 are respectively connected to the oil passage 62 connected to the oil tank 33, the pressure reducing valves 54, 59, and the pressure system passing through the relief valve 61 is liberated to the oil tank 33.

The brake circuit 42 includes a switch 63 as a detection means for detecting a pressure storage state of the pressure accumulator 60. The switch 63 is a switch for detecting the pressure in the first state and the second state according to the pressure storage state of the pressure accumulator 60. The state of the switch 63 is input to the controller 36. The switch 63 in the present embodiment is a device that accumulates pressure in the accumulator 60 at a predetermined pressure. The case is set to the first state (for example, the OFF state), and is set to the second state (for example, the ON state) when the predetermined pressure is not stored in the accumulator 60. The predetermined pressure is a pressure required for operating the hydraulic auxiliary brake devices 50 and 51.

The pressure compensation circuit 43 will be described.

The pressure compensation circuit 43 includes an oil passage 65 connected to the oil tank 33. The oil passage 65 is connected to the hydraulic pump 31 and functions as a third oil passage that connects the hydraulic pump 31 and the oil tank 33 without passing through the cargo handling system 41. A pressure compensation valve 66 is provided in the oil passage 65.

The pressure compensating valve 66 generates a pressure higher than the pressure input from the hydraulic pump 31 to the cargo loading / unloading circuit 41, and the pressure in the cargo loading / unloading circuit 41 becomes the operating pressure required for the cargo loading / unloading device 21 to operate. Way to compensate the valve. In addition, the pressure compensation valve 66 connects the hydraulic pump 31 and the oil tank 33 when the pressure in the circuit exceeds a predetermined relief pressure, and releases the pressure toward the oil tank 33. The hydraulic pump 31 and the oil tank 33 communicate with each other by operating the pressure compensation valve 66 to open the oil passage 65.

As shown in FIGS. 4 (a) and 4 (b), the pressure compensation valve 66 includes a valve body 66 a that opens or closes the oil passage 65. The pressure compensation valve 66 holds the valve body 66a by a spring (not shown), and when the pressure is not exceeded, the spring force and the pressure from the hydraulic cylinder input through the oil passage 67 generate a specific ratio toward the cargo. The pressure input from the loading / unloading circuit 41 is also high.

At this time, the valve body 66a is in a position where the hydraulic pump 31 and the oil tank 33 are not connected as shown by the solid line in the figure, that is, a position where the oil passage 65 is blocked. On the other hand, the pressure compensation valve 66 opens the drain valve 74 when a pressure exceeding the relief pressure is applied through the oil passage 65 because the oil passage 67 is released from the The pressure from the valve 74 to the orifice 75 decreases, so the pressure of the oil passage 65 defeats the spring force, so that the valve body 66a moves to the position connecting the hydraulic pump 31 and the oil groove 33 as shown by the two-point chain line in the figure. Open position (moves upward in the figure). Therefore, the pressure applied to the pressure compensating valve 66 through the oil passage 65 is released by the oil flowing to the oil groove 33 like the solid line arrow Y. The valve body 66a in this embodiment functions as a pressure receiving portion that receives the oil pressure of the oil passage 65.

The pressure compensation circuit 43 according to the present embodiment is provided with a applying mechanism 68 that applies a force to close the oil passage 65 to the pressure compensation valve 66 as shown in FIGS. 4 (a) and 4 (b). The applying mechanism 68 includes a solenoid 68a and a movable portion 68b that can be moved by the magnetic force of the solenoid 68a. The movable portion 68 b is a plunger that linearly moves with respect to the valve body 66 a of the pressure compensation valve 66 so as to be able to contact and separate and move. As shown in FIG. 4 (b), the valve body 66a of the pressure compensation valve 66 is in contact with the movable portion 68b, so that the operation of the open oil passage 65 is restricted. That is, the valve body 66a receives a force from the movable portion 68b and is restricted in its operation. The excitation and demagnetization of the solenoid 68 a of the mechanism 68 is controlled by the controller 36.

Returning to the description of FIG. 3, in the oil passage 67 connected to the hydraulic cylinder, there are a filter 72, an orifice 73, and a drain valve 74. In addition, an orifice 75 exists in the oil passage 67 closer to the cargo handling system circuit 41 than the connection portion of the pressure compensation valve 66.

Hereinafter, the operations of the hydraulic mechanism 32 mounted on the stacker 10 according to this embodiment, particularly the operations of the brake system circuit 42 and the pressure compensation circuit 43 will be described with reference to FIGS. 3 to 5.

When the cargo handling device 21 is activated, the controller 36 responds The cargo loading / unloading device 21 is controlled to operate the cargo loading / unloading device 21 at a speed of the operation amount of the cargo loading / unloading lever 18, and the hydraulic pump 31 is driven. Thereby, the hydraulic pressure generated by the driving of the hydraulic pump 31 is applied to the cargo loading / unloading system 41, and the supply / discharge of the hydraulic oil is switched by the respective control valves 45, 47, 49, so that the cargo loading / unloading device 21 performs desired operations. Cargo handling. In addition, the hydraulic pressure generated by the driving of the hydraulic pump 31 is also applied to the brake circuit 42 via the oil passage 53 to accumulate pressure in the accumulator 60. The pressure accumulated in the accumulator 60 is maintained by the check valve 56 so as to flow back to the hydraulic pump 31 without passing through the oil passage 53. In addition, the application mechanism 68 of the pressure compensation circuit 43 in this embodiment is not operated, and the operation of the valve body 66a of the pressure compensation valve 66 is not restricted.

When the braking force is applied to the stacker 10, the braking force is mainly provided by the rear wheel braking device. However, when the slipping of the rear wheel 15 is detected, the auxiliary braking devices 50 and 51 are also actuated to provide the braking force. . At this time, the controller 36 controls the switching valve 58 to release the pressure stored in the pressure accumulator 60. Thereby, the pressure from the accumulator 60 is applied to the auxiliary brake devices 50 and 51, and a braking force based on the auxiliary brake devices 50 and 51 is generated.

When, for example, the auxiliary brake devices 50 and 51 are continuously activated when the cargo handling device 21 is not activated, the pressure accumulation amount of the pressure accumulator 60 becomes insufficient. For this reason, the controller 36 performs control described below to accumulate the pressure of the accumulator 60.

When the pressure accumulation amount of the pressure accumulator 60 is lowered to a predetermined pressure, a signal is input to the controller 36 by the switch 63 transitioning from the first state to the second state. Therefore, the controller 36 determines that it is necessary to accumulate the pressure of the accumulator 60 based on the detection result of the switch 63. Based on this determination, since the controller 36 will The force of the oil lock path 65 is applied to the pressure compensating valve 66, so the applying mechanism 68 is operated as shown in FIG. 4 (b). Then, the controller 36 controls the cargo loading / unloading motor 30 to drive the hydraulic pump 31 when the cargo loading / unloading lever 18 is not operated. Accordingly, the hydraulic pressure generated by the driving of the hydraulic pump 31 is applied to the valve body 66 a of the pressure compensation valve 66 through the oil passage 65.

As shown in FIG. 4 (b), when the imparting mechanism 68 is operated, a force for closing the oil passage 65 is applied to the valve body 66a of the pressure compensation valve 66 through the movable portion 68b. Therefore, the hydraulic pressure generated by the driving of the hydraulic pump 31 is not released to the oil groove 33 because the oil passage 65 is blocked. Thereby, in the hydraulic pressure mechanism 32, since the hydraulic pressure generated by the driving of the hydraulic pump 31 is not released toward the oil groove 33, the hydraulic pressure in the oil passage 34 is increased. As a result, the oil pressure mechanism 32 generates oil pressure in the oil passage 53 connected to the brake system circuit 42 by the action of the pressure compensation circuit 43. Then, this hydraulic pressure is a hydraulic pressure that accumulates the pressure of the accumulator 60 and is stored in the accumulator 60 when the cargo handling device 21 is not activated. That is, the pressure required for operating the auxiliary brake devices 50 and 51 is accumulated in the accumulator 60.

FIG. 5 shows an example of changes in the pressure storage state of the pressure accumulator 60.

As shown in FIG. 5, when the auxiliary brake devices 50 and 51 are actuated under the pressure required to actuate the auxiliary brake devices 50 and 51, the pressure of the accumulator 60 is released (time t1). As a result, the pressure stored in the accumulator 60 decreases. Next, the pressure stored in the accumulator 60 decreases, and when the pressure is lower than a predetermined pressure ("X" in the figure), the pressure accumulation state is detected by the switch 63. With this, the controller 36 activates the imparting mechanism 68 at time t2 in the figure (the solenoid is turned on in the figure), and then makes the goods at time t3 in the figure. The object loading / unloading motor 30 operates (the motor is turned on in the figure). As a result, pressure is generated in the oil passage 53 connected to the brake system circuit 42 as described above, and the pressure is stored in the accumulator 60. After that, when the pressure stored in the accumulator 60 reaches a predetermined pressure, the pressure accumulation state is detected by the switch 63. As a result, the controller 36 stops the cargo loading / unloading motor 30 (the motor is turned off in the figure), and sets the imparting mechanism 68 to be inactive (the solenoid is turned off in the figure).

Therefore, according to this embodiment, the following effects can be obtained.

(1) When it is necessary to accumulate the pressure of the accumulator 60, a force is applied to the pressure compensating valve 66 by operating the application mechanism 68 to close the oil passage 65. Therefore, the hydraulic pressure generated by the driving of the hydraulic pump 31 is released to the oil groove 33 without the pressure compensation valve 66. As a result, an oil pressure is generated in the oil passage 53 connecting the hydraulic pump 31 and the brake system circuit 42 including the accumulator 60, and the accumulator 60 can be accumulated by the hydraulic pressure. Therefore, the pressure storage state of the pressure accumulator 60 can be favorably maintained.

(2) That is, even with the oil pressure mechanism 32 having the neutral closed-loop control valves 45, 47, 49 and the pressure compensation valve 66, the pressure accumulation state of the accumulator 60 can be maintained well, and the operation assistance can be performed well Brake device 50,51.

(3) Especially when the cargo handling device 21 is not in operation, the pressure storage state of the pressure accumulator 60 can be maintained well, and the auxiliary brake devices 50 and 51 can be operated well.

(4) Since the application mechanism 68 is configured to operate the movable portion 68b by the solenoid 68a, the application mechanism 68 can be miniaturized.

(5) Since the pressure of the accumulator 60 is directly detected by the switch 63, the pressure can be stored in the accumulator 60 at an appropriate timing.

(6) Since the brake circuit 42 has a check valve 56 on the upstream side of the connection portion of the accumulator 60, the pressure accumulation state of the accumulator 60 can be appropriately maintained.

(7) When the accumulator 60 is accumulating a predetermined pressure, stopping the cargo loading / unloading motor 30 can suppress power consumption exceeding a required amount. That is, energy saving effects can be produced.

The above embodiment may be modified as follows.

In an industrial vehicle having a plurality of hydraulic actuators (elevating cylinders 24, telescopic cylinders 25, and tilting cylinders 26) as in the embodiment, the pressure compensation valve 66 may be released according to the type of the hydraulic actuators that operate. Different pressure relief controls. The controller 36 is to replace the control command value (current command) of the solenoid 68a by changing the generated magnetic force according to the type of the hydraulic actuating device that operates, so as to adjust the operation amount of the movable portion 68b and make the pressure compensation valve The 66 has a different relief pressure. For example, the controller 36 adjusts when the tilt cylinder 26 is to be operated in a manner that the relief pressure becomes lower than when the lift cylinder 24 is to be operated. In this case, the controller 36 uses a sensor or the like to detect a member (in the embodiment, the lift lever 18a, the telescopic lever 18b, and the tilt lever 18c) for instructing the operation of the hydraulic actuator. The operating state is used to identify which of the plurality of hydraulic actuators will operate. For example, in the embodiment, the operating state of the lifting joystick 18a can be detected by the lifting sensor 37, the operating state of the telescopic joystick 18b can be detected by the telescopic sensor 38, and the tilt sensing is used. The device 39 can detect the operation state of the tilt lever 18c. As shown in FIG. 3, a pressure sensor 76 may be disposed in the oil passage 34 to detect the discharge pressure of the hydraulic pump 31 to detect the hydraulic pressure. Placing action. In this way, it is not necessary to directly detect the operation state of the cargo loading / unloading lever when performing the above-mentioned control. In addition, in the case where a plurality of hydraulic actuators are operated simultaneously, the controller 36 adjusts the imparting mechanism 68 in cooperation with the hydraulic actuators that need to set the minimum pressure of the hydraulic actuators to be operated. According to other examples, the relief pressure corresponding to the hydraulic actuator can be set.

The detection means for detecting the pressure accumulation state of the pressure accumulator 60 may be a means for detecting whether the auxiliary brake devices 50 and 51 have been activated. In this way, if it is detected whether the auxiliary brake devices 50 and 51 have been operated, it can be indirectly determined that the pressure accumulation amount of the pressure accumulator 60 is insufficient. Therefore, when the auxiliary brake devices 50 and 51 are actuated, the controller 36 can also perform the same control as in the embodiment to accumulate the pressure of the accumulator 60.

In order to detect the pressure storage state of the pressure accumulator 60, a pressure sensor may be provided instead of the switch 63. The detection result of the pressure sensor is input to the controller 36, and the controller 36 detects whether a predetermined pressure is being stored in the pressure accumulator 60, and controls the cargo loading / unloading motor 30 and the applying mechanism 68 based on the result.

When the accumulator 60 is stored at a predetermined pressure, the imparting mechanism 68 is deactivated, but the operation of the cargo loading / unloading motor 30 may be continued. Alternatively, after the application mechanism 68 is deactivated, the operation of the cargo loading / unloading motor 30 may be stopped.

When the controller 36 controls the pressure accumulator 60 to accumulate pressure, the cargo loading / unloading motor 30 and the application mechanism 68 may be operated simultaneously or substantially simultaneously.

It is necessary to make the pressure accumulator when the cargo handling device 21 operates In the case of accumulating pressure 60, the imparting mechanism 68 may be operated to accumulate the pressure of the accumulator 60.

When it is necessary to accumulate the pressure of the accumulator 60, the controller 36 can control the cargo loading and unloading motor 30 and the application mechanism 68 to accumulate the pressure of the accumulator 60 on the condition that the cargo loading and unloading device 21 is inoperative.

The cargo handling device may include an attachment.

As the control valves 45, 47, and 49 included in the cargo handling circuit 41, electromagnetic valves may be used.

The indicating member for instructing the cargo loading and unloading operation is not limited to a lever type such as the cargo loading and unloading lever 18, and may have other structures. For example, it may be a button type.

If it is a stacker provided with a hydraulic brake device, the stacker is not limited to a telescopic stacker, and the control of the embodiment may also be adopted.

Claims (7)

An industrial vehicle includes a hydraulic brake device and a hydraulic cargo handling device. The industrial vehicle includes a first hydraulic circuit, a pressure accumulator having a hydraulic pressure source serving as the brake device, and a pressure accumulator for detecting the pressure. The detection means used for the pressure storage state of the compressor; the first oil circuit is connected to the aforementioned first hydraulic circuit and the hydraulic pump; the second hydraulic circuit has the aforementioned hydraulic pump when the cargo handling operation means is not operated It is a non-connected mid-position closed-circuit control valve that is connected to the cargo loading and unloading device. The control valve is used to switch the supply and discharge of hydraulic oil to drive the cargo loading and unloading device. And the aforementioned hydraulic pump; a pressure compensation circuit having a pressure compensating valve located on a third oil path connecting the aforementioned hydraulic pump and an oil tank without passing through the aforementioned second hydraulic circuit, and a valve for closing the aforementioned third hydraulic circuit A force applying mechanism for applying pressure to the pressure compensation valve; and a control device that, when it is determined that it is necessary to accumulate the pressure of the accumulator based on a detection result of the detecting means, activates the applying mechanism and controls electric power The hydraulic pump is driven by the engine, and the force for closing the third oil path is applied to the pressure compensation valve by the action of the imparting mechanism, so that a pressure for accumulating the pressure of the accumulator is generated on the first oil path. Oil pressure. For example, the industrial vehicle of claim 1, wherein the pressure compensation valve has a pressure receiving portion that receives the oil pressure of the third oil passage, the imparting mechanism includes a solenoid, and a movable portion that is movable by the magnetic force of the solenoid. The pressure receiving portion of the pressure compensating valve receives a force from the movable portion to open the third oil passage. The industrial vehicle according to claim 1, wherein the first hydraulic circuit further includes a check valve for maintaining a pressure stored in the pressure accumulator. In the industrial vehicle of claim 1, wherein the control device stops the operation of the imparting mechanism and stops the electric motor when the predetermined pressure is stored in the accumulator. For example, the industrial vehicle according to any one of claims 1 to 4, wherein the cargo loading and unloading device has a plurality of hydraulic actuating devices, and the control device detects the movement of the hydraulic actuating device when the cargo loading and unloading device operates, and adjusts The release pressure of the pressure compensation valve corresponding to the hydraulic actuator is set by the force given by the aforementioned applying mechanism to lock the third oil passage. The industrial vehicle according to any one of claims 1 to 4, wherein the aforementioned braking device is a front wheel braking device of a telescopic stacker. The industrial vehicle according to claim 5, wherein the aforementioned braking device is a front wheel braking device of a telescopic stacker.