Industrial Vehicles

Abstract

To provide an industrial vehicle which enables multiple electric motors to be efficiently utilized compared with a case where use of each electric motor is fixed to one of traveling and cargo handling.SOLUTION: A forklift 10 includes: a cargo handling output path 35 formed between a cargo handling motor 31 and a cargo handling oil pump 32; a traveling output path 44 formed between a driving motor 41 and driving wheels 10T; a coordination output path 54 formed between the cargo handling output path 35 and the traveling output path 44; a cargo handling output blocking part 38 which may block transmission of output from the cargo handling motor 31 to the oil pump 32; and a coordination output blocking part 50 which may block transmission of output through the coordination output path 54. The coordination output blocking part 50 does not block transmission of the output from the cargo handling motor 31 to the traveling output path 44 through the coordination output path 54 when the transmission of the output from the cargo handling motor 31 to the oil pump 32 is blocked by the cargo handling output blocking part 38.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an industrial vehicle. [Background technology]

[0002] Conventionally, as a technology related to industrial vehicles, for example, the technology described in Patent Document 1 is known. Patent Document 1 discloses a battery forklift equipped with a traveling motor for driving the drive wheels and a loading motor provided in an electric hydraulic system device for raising and lowering the forks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-79637 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, for example, in the technical field of automobiles, electric vehicles that run only on electric motors without an internal combustion engine have been popularized from the viewpoint of environmental protection. Such replacement of internal combustion engines with electric motors is also being considered for application in the technical field of industrial vehicles such as forklifts. However, in industrial vehicles such as forklifts, the output characteristics of the drive sources required for driving and loading are different, while the output characteristics of the internal combustion engine and the electric motor are different. Therefore, simply replacing one internal combustion engine with one electric motor is likely to lead to an increase in size of the electric motor in order to obtain the same performance as the internal combustion engine for driving and loading, and is likely to be inefficient.

[0005] For these reasons, it is conceivable to provide a configuration in which one electric motor is provided for driving and one for loading and unloading, as in the above-mentioned conventional technology. However, when the use of each electric motor is fixed to either driving or loading and unloading in this way, it is necessary to ensure sufficient driving performance with the driving motor and sufficient loading and unloading performance with the loading and unloading motor, even though there are only a limited number of situations in which both driving and loading and unloading performance are required at the same time. Therefore, it tends to be difficult to use each electric motor efficiently.

[0006] The present invention aims to provide an industrial vehicle that can utilize multiple electric motors more efficiently than when the use of each electric motor is fixed to either traveling or loading and unloading. [Means for solving the problem]

[0007] An industrial vehicle according to one embodiment of the present invention is an industrial vehicle equipped with a first electric motor and a second electric motor, and is equipped with a loading output path formed between the first electric motor and an oil pump for loading and unloading, a propulsion output path formed between the second electric motor and wheels, a linked output path formed between the loading output path and the propulsion output path, a loading output cut-off unit capable of cutting off the transmission of output from the first electric motor to the oil pump, and a linked output cut-off unit capable of cutting off the transmission of output via the linked output path, and when the transmission of output from the first electric motor to the oil pump is cut off by the loading output cut-off unit, the linked output cut-off unit does not cut off the transmission of output from the first electric motor to the propulsion output path via the linked output path.

[0008] In an industrial vehicle according to an aspect of the present invention, for example, during travel after loading and unloading work, the oil pump does not necessarily require driving force. Therefore, the transmission of output from the first electric motor to the oil pump is cut off by the loading and unloading output cutoff unit, and the transmission of output from the first electric motor to the traveling output path via the linked output path is not cut off by the linked output cutoff unit, so that the first electric motor can drive the wheels instead of the oil pump. As a result, the wheels are in a state where they can be driven not only by the second electric motor but also by the first electric motor, and the first electric motor can be used for traveling. Therefore, it is possible to use multiple electric motors more efficiently than when the purpose of each electric motor is fixed to either traveling or loading and unloading.

[0009] In one embodiment, the vehicle includes a torque acquisition unit that acquires a wheel torque that drives the wheels, and a cutoff control unit that controls the loading output cutoff unit and the linked output cutoff unit based on the wheel torque, and when the wheel torque is equal to or greater than a predetermined torque threshold, the cutoff control unit may control the loading output cutoff unit to cut off transmission of output from the first electric motor to the oil pump, and control the linked output cutoff unit not to cut off transmission of output from the first electric motor to the traveling output path via the linked output path. In this case, the cutoff control unit can automatically control whether the first electric motor drives the oil pump or drives the wheels instead of the oil pump, based on the wheel torque acquired by the torque acquisition unit.

[0010] An industrial vehicle according to another aspect of the present invention is an industrial vehicle equipped with a first electric motor and a second electric motor, and comprising a loading output path formed between the first electric motor and a loading oil pump, a driving output path formed between the second electric motor and the wheels, a linked output path formed between the loading output path and the driving output path, a driving output cut-off unit capable of cutting off the transmission of output from the second electric motor to the wheels, and a linked output cut-off unit capable of cutting off the transmission of output via the linked output path, and when the transmission of output from the second electric motor to the wheels is cut off by the driving output cut-off unit, the linked output cut-off unit does not cut off the transmission of output from the second electric motor to the loading output path via the linked output path.

[0011] In the industrial vehicle according to another aspect of the present invention, the wheels do not necessarily require driving force, for example, during loading and unloading work while the vehicle is stopped. Therefore, the transmission of output from the second motor to the wheels is cut off by the driving output cutoff unit, and the transmission of output from the second motor to the loading and unloading output path via the linked output path is not cut off by the linked output cutoff unit, so that the second motor can drive the oil pump instead of the wheels. As a result, the oil pump can be driven not only by the first motor but also by the second motor, and the second motor can be used for loading and unloading. Therefore, it is possible to use multiple motors more efficiently than when the purpose of each motor is fixed to either driving or loading and unloading.

[0012] In one embodiment, the vehicle includes a pressure acquisition unit that acquires the pressure of a lift cylinder for loading and unloading, and a cutoff control unit that controls the traveling output cutoff unit and the linked output cutoff unit based on the pressure of the lift cylinder, and when the pressure of the lift cylinder is equal to or higher than a predetermined pressure threshold, the cutoff control unit may control the traveling output cutoff unit to cut off the transmission of output from the second electric motor to the wheels, and control the linked output cutoff unit not to cut off the transmission of output from the second electric motor to the loading and unloading output path via the linked output path. In this case, the cutoff control unit can automatically control the traveling output cutoff unit and the linked output cutoff unit to determine whether the second electric motor drives the wheels or drives the oil pump instead of the wheels, based on the pressure of the lift cylinder acquired by the pressure acquisition unit.

[0013] In one embodiment, the driving output path may have a plurality of driving gear pairs corresponding to a plurality of gear ratios, and the driving output cutoff unit may be a hub sleeve provided for each of the plurality of driving gear pairs. In this case, the vehicle speed range at which the industrial vehicle can travel is expanded in accordance with the plurality of gear ratios. Also, the driving output can be switched between being cut off and not being cut off depending on whether the driving gear pair and the hub sleeve are engaged with each other.

[0014] In one embodiment, the industrial vehicle further includes a first shaft connected to the output shaft of the first motor and a second shaft arranged adjacent to the first shaft and connected to the output shaft of the second motor, the cooperative output path has a cooperative gear pair provided between the first shaft and the second shaft, and the cooperative output cutoff unit may be a hub sleeve provided on the cooperative gear pair. In this case, since the first motor and the second motor are adjacent to each other, it is possible to reduce the size of the motors by efficiently using multiple motors, and to save space. As a result, it is possible to improve the freedom of layout in the industrial vehicle. Effect of the Invention

[0015] According to the present invention, it is possible to utilize a plurality of electric motors more efficiently than in the case where the use of each electric motor is fixed to either traveling or loading / unloading. [Brief description of the drawings]

[0016] [Figure 1] 1 is a block diagram showing a schematic configuration of an industrial vehicle according to an embodiment; [Diagram 2] 2 is a schematic configuration diagram showing an example of a drive system of the industrial vehicle shown in FIG. 1. [Diagram 3] 3 is a diagram showing a state in which the transmission of output through a cooperative output path in the drive system of FIG. 2 is interrupted. FIG. [Figure 4] FIG. 3 is a diagram showing a state in which the transmission of output from the first electric motor to the oil pump is cut off by the load output cutoff unit in the drive system of FIG. 2, but the transmission of output from the first electric motor to the driving output path via the linked output path is not cut off. [Diagram 5] FIG. 3 is a diagram showing a state in which the transmission of output from the second electric motor to the wheels is interrupted by the driving output cut-off unit in the drive system of FIG. 2, but the transmission of output from the second electric motor to the loading output path via the linked output path is not interrupted. [Figure 6] FIG. 4 is a diagram illustrating an example of a relationship between wheel torque and wheel rotation speed. [Figure 7] FIG. 7 is a diagram for explaining a predetermined travel of the industrial vehicle in FIG. 6. [Figure 8] FIG. 4 is a diagram illustrating an example of a relationship between a flow rate of an oil pump and a discharge pressure of the oil pump. [Figure 9] 2 is a flowchart showing an example of a calculation process performed by the control device of FIG. 1. [Figure 10] 2 is a flowchart showing an example of a calculation process performed by the control device of FIG. 1. [Figure 11] FIG. 13 is a schematic diagram showing a modified example of the drive system of the industrial vehicle. [Figure 12] FIG. 10 is a diagram showing a state in which the transmission of output from the first electric motor to the oil pump is cut off by the load output cut-off unit in the drive system of FIG. 9, but the transmission of output from the first electric motor to the driving output path via the linked output path is not cut off. [Figure 13] FIG. 13 is a schematic diagram showing another modified example of the drive system of the industrial vehicle. [Figure 14] FIG. 13 is a schematic diagram showing still another modified example of the drive system of the industrial vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0018] FIG. 1 is a block diagram showing a schematic configuration of an industrial vehicle according to an embodiment. FIG. 1 shows a forklift 10 as an example of an industrial vehicle. The forklift 10 is configured as an electric vehicle that runs on a motor. The power source for the motor is, for example, a battery mounted on the machine base (vehicle body). The forklift 10 is not particularly limited, but may be, for example, a relatively large four-wheeled vehicle. The forklift 10 may be of a type in which a motor is mounted on a machine base on which an internal combustion engine is conventionally mounted, instead of an internal combustion engine.

[0019] The forklift 10 includes, for example, a pair of front wheels (wheels) provided at the front and a pair of rear wheels provided at the rear. The front wheels here are driving wheels 10T (see FIG. 2), and the rear wheels (not shown) are steering wheels.

[0020] The forklift 10 is equipped with a loading device. The loading device may be provided in front of the driver's seat. The loading device has a mast, a lift cylinder 10L, a tilt cylinder, and a fork.

[0021] The forklift 10 may include a driver's seat. The driver's seat is provided with, for example, a loading operation lever 11 for loading and unloading operations, an accelerator pedal 12 for forward and backward operation, and a steering wheel 13 for steering operations. The loading operation lever 11 may include a lift lever and a tilt lever. The lift lever is a lever for operating a lift operation that moves the forks in the vertical direction. The tilt lever is a lever for operating a tilt operation that tilts the loading device. When the lift lever is operated, the lift cylinder 10L is driven to extend and retract, causing the mast to slide and retract in the vertical direction, and the forks are raised and lowered in conjunction with this. When the tilt lever is operated, the tilt cylinder is driven to extend and retract, causing the lower part of the mast to move in the front-rear direction, and the tilt angle of the loading device is adjusted.

[0022] The forklift 10 includes a drive system 20. The drive system 20 is a device for transmitting power generated in a motor to wheels, etc. The drive system 20 includes a loading drive system 30 and a traveling drive system 40.

[0023] The cargo handling drive system 30 is a power train that generates a driving force for operating the cargo handling device. The cargo handling drive system 30 drives the lift cylinder 10L and the tilt cylinder by supplying hydraulic oil to them. The cargo handling drive system 30 includes a cargo handling motor (first electric motor) 31 and a cargo handling oil pump 32 that pumps hydraulic oil to each of the lift cylinder 10L and the tilt cylinder. The cargo handling motor 31 is a drive source that mainly drives the oil pump 32.

[0024] The oil pump 32 supplies hydraulic oil to the lift cylinder 10L and tilt cylinder via a valve section that controls the supply destination and supply amount. For example, when the driver operates the lift lever, the valve in the valve section that corresponds to the lift cylinder 10L opens to an opening degree according to the amount of operation, and the other valves close. The loading motor 31 rotates at a rotation speed according to the amount of operation, and pumps hydraulic oil. The pumped hydraulic oil is supplied to the lift cylinder 10L via the open valve.

[0025] The lift cylinder 10L is provided with a hydraulic sensor (pressure acquisition unit) 14. The hydraulic sensor 14 detects the pressure of the lift cylinder 10L. The pressure of the lift cylinder 10L corresponds to the load of the forklift, and corresponds to the weight of a load loaded on the forklift.

[0026] The traveling drive system 40 is a power train that generates a driving force for driving the driving wheels 10T to travel the forklift 10. The traveling drive system 40 drives the driving wheels 10T by transmitting a rotational force to the driving wheels 10T. The traveling drive system 40 includes a traveling motor (second electric motor) 41. The traveling motor 41 is a driving source mainly for driving the driving wheels 10T.

[0027] When the driver operates the accelerator pedal 12, the traveling motor 41 rotates at a rotation speed corresponding to the amount of operation of the accelerator pedal 12. The traveling drive system 40 also includes a steering mechanism that steers the rear wheels based on the operation of the steering wheel 13.

[0028] In this embodiment, as described in detail below, the loading motor 31 can also drive the drive wheels 10T, and the traveling motor 41 can also drive the oil pump 32. That is, the forklift 10 includes the loading motor 31 as a first electric motor and the traveling motor 41 as a second electric motor. The first electric motor drives either the oil pump 32 or the drive wheels 10T. The second electric motor drives either the oil pump 32 or the drive wheels 10T.

[0029] Fig. 2 is a schematic diagram showing an example of a drive system of the industrial vehicle of Fig. 1. As shown in Fig. 2, the drive system 20 has a gear box 21. As an example, the gear box 21 has a case 22, an input shaft (first shaft) 33, an input shaft (second shaft) 42, an output shaft 34, and an output shaft 43. The input shaft 33, the input shaft 42, the output shaft 34, and the output shaft 43 are each supported by, for example, a bearing fixed to the case 22 of the gear box 21. The gear box 21 transmits an output (driving torque) input from at least one of the loading motor 31 and the traveling motor 41 to at least one of the two output shafts 34 and the output shaft 43.

[0030] A loading output path 35 is formed between the loading motor 31 and the oil pump 32. The input shaft 33 is connected to, for example, the output shaft of the loading motor 31 so as to be rotatable together with the output shaft of the loading motor 31. The output shaft 34 is connected to the input shaft of the oil pump 32 so as to be rotatable together with the input shaft of the oil pump 32. In the example of Fig. 2, the output shaft 34 and the oil pump 32 are directly connected to each other, but the output shaft 34 and the oil pump 32 may be indirectly connected to each other by providing, for example, a joint between the output shaft 34 and the oil pump 32.

[0031] A constantly meshing cargo handling gear pair 36 is provided between the input shaft 33 and the output shaft 34. A hub sleeve 37 is provided in the cargo handling gear pair 36. The cargo handling gear pair 36 is a pair of gears 36a, 36b that have a diameter dimension that provides a predetermined speed ratio and are constantly meshed with each other. The gear 36a is journaled so as to be rotatable relative to the input shaft 33, and can rotate independently of the input shaft 33. The gear 36b is fixed to the output shaft 34 and rotates together with the output shaft 34.

[0032] The hub sleeve 37 is fitted to the input shaft 33, for example, by a spline, and rotates together with the input shaft 33. The hub sleeve 37 is capable of moving toward or away from the gear 36a of the load-handling gear pair 36 along the input shaft 33. A plurality of protrusions are formed on the gear 36a side of the hub sleeve 37 so as to correspond to a plurality of projections and recesses provided on the side surface of the gear 36a. The hub sleeve 37 is capable of engaging with the side surface of the gear 36a.

[0033] The rotation and torque of the input shaft 33 is transmitted to the gear 36a via the hub sleeve 37 in a state in which the hub sleeve 37 is engaged with the side surface of the gear 36a. The gear 36a rotates the gear 36b, whereby the rotation and torque of the input shaft 33 are transmitted to the output shaft 34. In other words, a loading output path 35 including the input shaft 33, the hub sleeve 37, the loading gear pair 36 (gears 36a, 36b), and the output shaft 34 is formed between the loading motor 31 and the oil pump 32.

[0034] When the hub sleeve 37 moves away from the gear 36a and is no longer engaged with the side surface of the gear 36a, the hub sleeve 37 does not transmit the rotation and torque of the input shaft 33 to the gear 36a. When the hub sleeve 37 is not engaged with the side surface of the gear 36a, the rotation of the input shaft 33 is transmitted only to the hub sleeve 37. In other words, the rotation and torque of the input shaft 33 are not transmitted to the gears 36a, 36b, and the output shaft 34. In other words, when the hub sleeve 37 is not engaged with the side surface of the gear 36a, the transmission of the output from the loading motor 31 to the oil pump 32 is interrupted. The hub sleeve 37 here functions as a loading output interrupting unit 38 that can interrupt the transmission of the output from the loading motor 31 to the oil pump 32.

[0035] A traveling output path 44 is formed between the traveling motor 41 and the drive wheels 10T. The input shaft 42 is, for example, connected to the output shaft of the traveling motor 41 so as to be rotatable together with the output shaft of the traveling motor 41. The output shaft 43 is the output shaft of the gear box 21. The output shaft 43 is connected to the drive shaft of the drive wheels 10T so as to be rotatable together with the drive wheels 10T. In the example of FIG. 2, the output shaft 43 and the drive wheels 10T are directly connected, but the output shaft 43 and the drive wheels 10T may be indirectly connected by providing, for example, a joint between the output shaft 43 and the drive wheels 10T.

[0036] A constantly meshing running gear pair 45 is provided between the input shaft 42 and the output shaft 43. A hub sleeve 46 is provided in the running gear pair 45. The running gear pair 45 is a pair of gears 45a, 45b that have a diameter dimension that provides a predetermined speed ratio and are constantly meshed with each other. The gear 45b is journaled so as to be rotatable relative to the output shaft 43, and can rotate independently of the output shaft 43. The gear 45a is fixed to the input shaft 42 and rotates together with the input shaft 42.

[0037] The hub sleeve 46 is fitted to the output shaft 43, for example, by a spline, and rotates together with the output shaft 43. The hub sleeve 46 is capable of moving toward or away from the gear 45b of the running gear pair 45 along the output shaft 43. A plurality of protrusions are formed on the gear 45b side of the hub sleeve 46 so as to correspond to a plurality of projections and recesses provided on the side surface of the gear 45b. The hub sleeve 46 is capable of engaging with the side surface of the gear 45b.

[0038] The rotation and torque of the input shaft 42 are transmitted to the gear 45b as the gear 45a rotates the gear 45b, and are then transmitted to the output shaft 43 via the hub sleeve 46 when the hub sleeve 46 is engaged with the side surface of the gear 45b. In other words, a traveling output path 44 including the input shaft 42, the traveling gear pair 45 (gears 45a, 45b), the hub sleeve 46, and the output shaft 43 is formed between the traveling motor 41 and the drive wheel 10T.

[0039] When the hub sleeve 46 moves away from the gear 45b and is no longer engaged with the side surface of the gear 45b, it does not transmit the rotation and torque of the gear 45a to the output shaft 43. When the hub sleeve 46 is not engaged with the side surface of the gear 45b, the rotation of the gear 45a is transmitted only to the gear 45b. In other words, the rotation and torque of the input shaft 42 are not transmitted to the output shaft 43. In other words, when the hub sleeve 46 is not engaged with the side surface of the gear 45b, the transmission of the output from the traveling motor 41 to the driving wheels 10T is interrupted. The hub sleeve 46 here functions as a traveling output interruption unit 47 that can interrupt the transmission of the output from the traveling motor 41 to the driving wheels 10T.

[0040] The input shaft 42 is disposed adjacent to the input shaft 33. Here, the input shaft 42 is disposed adjacent to and parallel to the input shaft 33. The cargo motor 31 and the traveling motor 41 are attached to the gear box 21 adjacent to each other. Driving torque can be input to the gear box 21 independently from the cargo motor 31 and the traveling motor 41.

[0041] A constantly meshing linked gear pair 51 is provided between the input shaft 33 and the input shaft 42. A hub sleeve 52 is provided in the linked gear pair 51. The linked gear pair 51 is a pair of gears 45a, 53 that have a diameter dimension that provides a predetermined speed ratio and are constantly meshed with each other. The gear 53 is journaled so as to be rotatable relative to the input shaft 33, and can rotate independently of the input shaft 33. As described above, the gear 45a is fixed to the input shaft 42 and rotates together with the input shaft 42.

[0042] The diameter of the gear 45a is, for example, smaller than the diameter of the gear 53. The linking gear pair 51 has a gear ratio that reduces the rotation speed of the traveling motor 41 and transmits the reduced rotation speed to the loading output path 35. This allows the traveling motor 41 to be used with specifications for traveling, so that it has an appropriate rotation speed and torque as a driving source for loading and unloading.

[0043] The hub sleeve 52 is fitted to the input shaft 33, for example, by a spline, and rotates together with the input shaft 33. The hub sleeve 52 is capable of moving toward or away from the gear 53 of the interlocking gear pair 51 along the input shaft 33. A plurality of protrusions are formed on the gear 53 side of the hub sleeve 52 so as to correspond to a plurality of projections and recesses provided on the side surface of the gear 53. The hub sleeve 52 is capable of engaging with the side surface of the gear 53.

[0044] The rotation and torque of the input shaft 42 are transmitted to the gear 53 by the gear 45a rotating the gear 53, and are transmitted to the input shaft 33 via the hub sleeve 52 when the hub sleeve 52 is engaged with the side surface of the gear 53. Conversely, the rotation and torque of the input shaft 33 are transmitted to the gear 53 via the hub sleeve 52 when the hub sleeve 52 is engaged with the side surface of the gear 53. The rotation and torque of the input shaft 33 are transmitted to the gear 45a by the gear 53 rotating the gear 45a, and are transmitted to the input shaft 42. That is, a cooperative output path 54 including the input shaft 42, the cooperative gear pair 51 (gears 45a, 53), the hub sleeve 52, and the input shaft 33 is formed between the loading output path 35 and the traveling output path 44.

[0045] When the hub sleeve 52 moves away from the gear 53 and is no longer engaged with the side surface of the gear 53, rotation and torque are not transmitted from one of the input shaft 42 and the input shaft 33 to the other. In other words, when the hub sleeve 52 does not engage with the side surface of the gear 53, the transmission of output via the cooperative output path 54 is cut off. That is, the hub sleeve 52 here functions as a cooperative output cut-off unit 50 that can cut off the transmission of output via the cooperative output path 54. The cooperative output cut-off unit 50 here is the hub sleeve 52 provided on the cooperative gear pair 51.

[0046] The operation of the drive system 20 thus configured will be described with reference to Figures 3 to 5. Figure 3 is a diagram showing a state in which the transmission of output through the cooperative output path in the drive system of Figure 2 is interrupted. In the example of Figure 3, the hub sleeve 37 is engaged with the side surface of the gear 36a, the hub sleeve 46 is engaged with the side surface of the gear 45b, and the hub sleeve 52 is not engaged with the side surface of the gear 53. Therefore, the transmission of output from the loading motor 31 to the oil pump 32 is not interrupted, the transmission of output from the travel motor 41 to the drive wheel 10T is not interrupted, and the transmission of output through the cooperative output path 54 is interrupted.

[0047] In this case, the load output path 35 and the traveling output path 44 operate independently. Specifically, the output of the load motor 31 is transmitted to the gear 36a via the hub sleeve 37 fitted to the input shaft 33, and is transmitted to the output shaft 34 by the gear 36a rotating the gear 36b, and is transmitted to the oil pump 32. The output of the traveling motor 41 is transmitted to the gear 45b by the gear 45a fixed to the input shaft 42 rotating the gear 45b, and is transmitted to the output shaft 43 via the hub sleeve 46, and is transmitted to the drive wheel 10T. The output of the load motor 31 is not transmitted to the traveling output path 44 via the cooperative output path 54, and the output of the traveling motor 41 is not transmitted to the load output path 35 via the cooperative output path 54.

[0048] Fig. 4 is a diagram showing a state in which the load output cutoff unit cuts off the transmission of output from the first electric motor to the oil pump, but the transmission of output from the first electric motor to the traveling output path via the cooperative output path is not cut off in the drive system of Fig. 2. In the example of Fig. 4, the hub sleeve 37 is not engaged with the side of the gear 36a, the hub sleeve 46 is engaged with the side of the gear 45b, and the hub sleeve 52 is engaged with the side of the gear 53. Therefore, the transmission of output from the load motor 31 to the oil pump 32 is cut off, the transmission of output from the traveling motor 41 to the drive wheel 10T is not cut off, and the transmission of output via the cooperative output path 54 is not cut off.

[0049] In this case, the loading motor 31 operates in cooperation with the traveling motor 41 to assist it. Specifically, the output of the traveling motor 41 is transmitted to the drive wheel 10T in the same manner as in the example of FIG. 3. Here, the output of the loading motor 31 is further transmitted to the traveling output path 44 via the cooperation output path 54. The output of the loading motor 31 is transmitted to the gear 53 via the hub sleeve 52 fitted to the input shaft 33, and is transmitted to the input shaft 42 by the gear 53 rotating the gear 45a, and is transmitted to the traveling output path 44. As a result, the output of the loading motor 31 is transmitted to the traveling output path 44 via the cooperation output path 54, while the output of the traveling motor 41 is not transmitted to the loading output path 35.

[0050] Fig. 5 is a diagram showing a state in which the transmission of output from the second motor to the wheels is interrupted by the traveling output interruption unit, but the transmission of output from the second motor to the load output path via the cooperative output path is not interrupted in the drive system of Fig. 2. In the example of Fig. 5, the hub sleeve 37 is engaged with the side of the gear 36a, the hub sleeve 46 is not engaged with the side of the gear 45b, and the hub sleeve 52 is engaged with the side of the gear 53. Therefore, the transmission of output from the traveling motor 41 to the drive wheels 10T is interrupted, the transmission of output from the load motor 31 to the oil pump 32 is not interrupted, and the transmission of output via the cooperative output path 54 is not interrupted.

[0051] In this case, the traveling motor 41 operates in cooperation with the loading motor 31 to assist it. Specifically, the output of the loading motor 31 is transmitted to the oil pump 32 in the same manner as in the example of FIG. 3. Here, the output of the traveling motor 41 is further transmitted to the loading output path 35 via the cooperation output path 54. The output of the traveling motor 41 is transmitted to the gear 53 by the gear 45a fixed to the input shaft 42 rotating the gear 53, and is transmitted to the input shaft 33 via the hub sleeve 52 engaged with the gear 53, and is transmitted to the loading output path 35. As a result, the output of the traveling motor 41 is transmitted to the loading output path 35 via the cooperation output path 54, while the output of the loading motor 31 is not transmitted to the traveling output path 44.

[0052] Returning to Fig. 1, the forklift 10 has a control device 60 that controls the drive system 20. The control device 60 is a device for controlling the operation of the forklift 10. The control device 60 controls the drive system 20 based on the operation of the cargo handling operation lever 11 and the accelerator pedal 12.

[0053] The control device 60 is an electronic control unit having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. In the control device 60, for example, a program recorded in the ROM is loaded into the RAM, and the program loaded into the RAM is executed by the CPU, thereby realizing various functions. Note that the control device 60 may be composed of multiple electronic units.

[0054] The control device 60 is electrically connected to the cargo handling operation lever 11, the accelerator pedal 12, and the steering wheel 13, and receives operation commands from these. The control device 60 is electrically connected to the hydraulic sensor 14, and receives a detection signal of the pressure of the lift cylinder 10L transmitted from the hydraulic sensor 14. The control device 60 is electrically connected to the drive system 20, and transmits a control signal for controlling the drive system 20.

[0055] Next, a description will be given of the functional configuration of the control device 60. The control device 60 has a loading state acquisition unit (pressure acquisition unit) 61, a traveling state acquisition unit (torque acquisition unit) 62, and an output control unit (shutoff control unit) 63.

[0056] The loading status acquisition unit 61 acquires the status (load) of the loading device. The status of the loading device is obtained by the pressure of the lift cylinder 10L. The loading status acquisition unit 61 acquires the pressure of the lift cylinder 10L based on the detection result of the hydraulic sensor 14, for example.

[0057] The traveling state acquisition unit 62 acquires the state of the driving wheel 10T as the traveling state of the forklift 10. The state of the driving wheel 10T includes the wheel torque and the wheel rotation speed. The traveling state acquisition unit 62 can calculate the wheel torque driving the driving wheel 10T, for example, using a known conversion formula or the like based on the depression amount of the accelerator pedal 12. The wheel torque is an estimated value of the torque equivalent to the driving force of the driving wheel 10T. The value of the wheel torque may change prior to the actual driving torque of the driving wheel 10T, or may represent a target value of the driving force of the driving wheel 10T. The traveling state acquisition unit 62 can calculate the wheel rotation speed, for example, using a known conversion formula or the like based on the rotation speed of the traveling motor 41.

[0058] The output control unit 63 controls the state of the drive system 20, including the output (power running) of the loading motor 31 and the output (power running) of the traveling motor 41, based on the acquired state of the loading device, the state of the drive wheels 10T, and the operation amount of the loading operation lever 11 and the accelerator pedal 12. For example, the output control unit 63 controls the loading motor 31 so as to have a rotation speed corresponding to the operation amount of the loading operation lever 11 by sending a control signal to the loading motor 31. For example, the output control unit 63 controls the traveling motor 41 so as to have a rotation speed corresponding to the depression amount of the accelerator pedal 12 by sending a control signal to the traveling motor 41. The output control unit 63 controls the loading output, the traveling output, and whether or not the loading motor 31 and the traveling motor 41 are linked together by sending a control signal to the drive system 20.

[0059] [The loading motor assists the travel motor] The output control unit 63 can control the loading output cutoff unit 38 and the cooperative output cutoff unit 50 based on the wheel torque.

[0060] FIG. 6 is a diagram showing an example of the relationship between the wheel torque and the wheel rotation speed. The horizontal axis of FIG. 6 is the wheel rotation speed, which corresponds to the vehicle speed of the forklift 10. The vertical axis of FIG. 6 is the wheel torque, which corresponds to the target value of the driving force of the driving wheel 10T, and in this embodiment, is the torque target value calculated from the depression amount of the accelerator pedal 12. The solid line L1B in FIG. 6 shows the output characteristic of the traveling motor 41. The dashed line L1A in FIG. 6 shows the output characteristic on the output shaft 43 of the loading motor 31. The solid line L1C in FIG. 6 shows the output characteristic when the output of the loading motor 31 is added to the output of the traveling motor 41. Each plot in FIG. 6 is a trajectory of the state of the driving wheel 10T when the forklift 10 travels in a predetermined manner. The output characteristic of the traveling motor 41 is set to an output characteristic that includes, for example, a plot on the high vehicle speed side in FIG. 6 so that the forklift 10 can travel against the traveling resistance assumed in the design of the forklift 10.

[0061] Fig. 7 is a diagram for explaining a predetermined traveling of the industrial vehicle in Fig. 6. As an example, the predetermined traveling is assumed to be a driving pattern in which an unloaded forklift 10 is stopped or moving slowly, lifts a load using the loading device, starts with the load lifted, and increases the vehicle speed.

[0062] During a given travel, when an unloaded forklift 10 is stopped or moving slowly and is about to lift a load using the loading device, the forklift 10 is required to drive both the loading device and the drive wheels 10T. In such a situation, the locus (plot) of the state of the drive wheels 10T is likely to exist in the area DR1 surrounded by the dashed line. The area DR1 surrounded by the dashed line corresponds to an area where the wheel rotation speed is less than a predetermined value and the wheel torque is less than a predetermined value. The predetermined value of the wheel torque is, for example, an upper limit torque value that can be taken on the low vehicle speed side of the traveling motor 41. The low vehicle speed side may be, for example, a vehicle speed lower than the maximum vehicle speed of the loading motor 31 (vehicle speed at the right end of the dashed line L1A) aligned with the coordinate system of FIG. 6.

[0063] When the wheel torque is less than a predetermined torque threshold, the output control unit 63 may control the load output cutoff unit 38 so as not to cut off the transmission of the output from the load motor 31 to the oil pump 32, and may control the cooperative output cutoff unit 50 so as to cut off the transmission of the output from the load motor 31 to the traveling output path 44 via the cooperative output path 54. The predetermined torque threshold is a wheel torque threshold for determining whether the load motor 31 operates in cooperation with the traveling motor 41 to assist it. The torque threshold is set to, for example, a value shown as a solid line L1B in FIG. 6. The torque threshold may be set to a value shown as a dashed line Th1 in FIG. 7. By setting such a torque threshold, the region DR1 surrounded by the dashed line is included in the region below the torque threshold.

[0064] 7 is an example of a trajectory of the state of the drive wheels 10T in a driving pattern in which the forklift 10 starts traveling and increases its vehicle speed. Among the dashed dotted line DR2, the dashed dotted line DR2a, which is a portion where the wheel rotation speed rises from the point of 0, corresponds to the time when the forklift 10 starts traveling.

[0065] When the forklift 10, which has lifted a load using the loading device, starts traveling, the driving force of the drive wheels 10T required for the forklift 10 to travel tends to increase according to the weight of the load. In such a situation, as shown by the dashed line DR2a, the wheel torque (target value of the driving force) may be equal to or greater than a torque threshold. In this case, the output control unit 63 may control the loading output cutoff unit 38 to cut off the transmission of the output from the loading motor 31 to the oil pump 32 when the wheel torque is equal to or greater than a predetermined torque threshold, and may control the cooperative output cutoff unit 50 not to cut off the transmission of the output from the loading motor 31 to the traveling output path 44 via the cooperative output path 54. In other words, when the transmission of the output from the loading motor 31 to the oil pump 32 is cut off by the loading output cutoff unit 38, the cooperative output cutoff unit 50 does not cut off the transmission of the output from the loading motor 31 to the traveling output path 44 via the cooperative output path 54. As a result, the drive system 20 is set to a state in which the loading motor 31 operates in cooperation with the traveling motor 41 to assist it, as shown in Fig. 4. Since the output of the loading motor 31 is transmitted to the traveling output path 44 via the cooperative output path 54, the driving force of the driving wheel 10T can be realized by adding the output of the loading motor 31 to the output of the traveling motor 41. In the examples of Figs. 6 and 7, the driving force of the driving wheel 10T can be realized within a range whose upper limit is the solid line L1C.

[0066] In addition, among the dashed-dotted line DR2 in Fig. 7, the dashed-dotted line DR2b on the high vehicle speed side from the apex corresponds to a situation where the vehicle speed of the forklift 10 increases with the load-handling device lifting a load, and the acceleration becomes gentler than when the forklift 10 starts to travel. Therefore, in the example of Fig. 7, the wheel torque required for travel gradually decreases. For example, when the driving force of the drive wheel 10T can be provided by the output of the travel motor 41, the link between the travel motor 41 and the load-handling motor 31 is released. As shown in Fig. 3, the drive system 20 is set to a state in which the load-handling output path 35 and the traveling output path 44 operate independently of each other.

[0067] [The traveling motor assists the loading motor] The output control unit 63 controls the traveling output cutoff unit 47 and the cooperative output cutoff unit 50 based on the pressure of the lift cylinder 10L (hereinafter, may be simply referred to as "pressure").

[0068] FIG. 8 is a diagram showing an example of the relationship between the flow rate of the oil pump and the discharge pressure. The horizontal axis of FIG. 8 is the discharge flow rate of the oil pump 32, which increases or decreases according to the rotation speed of the oil pump 32. The vertical axis of FIG. 8 is the discharge pressure of the oil pump 32, which corresponds to the target value of the pressure of the hydraulic oil supplied to the loading device. The solid line L2A in FIG. 8 shows the output characteristic of the oil pump 32 by the loading motor 31. The dashed line L2B in FIG. 8 shows the output characteristic of the oil pump 32 by the traveling motor 41. The solid line L2C in FIG. 8 shows the output characteristic of the oil pump 32 when the output of the loading motor 31 is added to the output of the traveling motor 41. The solid line L2A and the dashed line L2B are determined by the characteristics of the loading motor 31, the traveling motor 41, and the oil pump 32 mounted on the forklift 10. Each plot in FIG. 8 is a trajectory of the discharge pressure of the oil pump 32 when the forklift 10 performs a predetermined loading operation. As an example, the predetermined loading operation is assumed to be a work pattern of the forklift 10. Each plot shows the position of the operating point of the lift operation and / or tilt operation with or without a load relative to the output of the oil pump 32. Area LD1 shows the case where the lift operation is performed with a maximum load. Area LD2 shows the case where the lift operation is performed with an empty load. Area LD3 shows the case where only the tilt operation is performed with a maximum load and with an empty load.

[0069] In Fig. 8, when the load is increased from the region LD2 in an unloaded state, there is a boundary between the region LD2 and the maximum load region LD1, where the output is insufficient with only the cargo motor 31. This boundary is the upper limit pressure value when the oil pump 32 is driven only by the cargo motor 31, and corresponds to the solid line L2A in Fig. 8.

[0070] Therefore, the output control unit 63 sets the pressure of the lift cylinder 10L corresponding to the load shown by the solid line L2A as the pressure threshold. When the pressure of the lift cylinder 10L is equal to or higher than the predetermined pressure threshold, the output control unit 63 may control the traveling output cutoff unit 47 to cut off the transmission of the output from the traveling motor 41 to the driving wheels 10T, and may control the cooperative output cutoff unit 50 not to cut off the transmission of the output from the traveling motor 41 to the loading output path 35 via the cooperative output path 54. In other words, when the transmission of the output from the traveling motor 41 to the driving wheels 10T is cut off by the traveling output cutoff unit 47, the cooperative output cutoff unit 50 does not cut off the transmission of the output from the traveling motor 41 to the loading output path 35 via the cooperative output path 54. The predetermined pressure threshold is a pressure threshold for determining whether the traveling motor 41 operates in cooperation with the loading motor 31 to assist it. By setting such pressure thresholds, each plot (e.g., area LD1) of the discharge pressure when the lift cylinder 10L is driven under high load is included in the range with the solid line L2C as the upper limit. If the traveling motor 41 is switched to assist the cargo motor 31 while traveling, a sudden deceleration may occur, so it is preferable to limit the assistance of the cargo motor 31 by the traveling motor 41 to cases where the traveling function is not required.

[0071] As a result, the drive system 20 is set to a state in which the traveling motor 41 operates in cooperation with the loading motor 31 to assist the loading motor 31, as shown in Fig. 5. Since the output of the traveling motor 41 is transmitted to the loading output path 35 via the cooperation output path 54, the discharge pressure of the oil pump 32 can be realized by adding the output of the traveling motor 41 to the output of the loading motor 31. In the example of Fig. 8, the discharge pressure of the oil pump 32 can be realized within a range whose upper limit is the solid line L2C.

[0072] When the pressure of the lift cylinder 10L equal to or greater than the pressure threshold is no longer required, the link between the traveling motor 41 and the loading motor 31 is released. As shown in FIG. 3, the drive system 20 is set to a state in which the loading output path 35 and the traveling output path 44 operate independently.

[0073] In addition, the area LD2 surrounded by the dashed line in FIG. 8 includes a plot of the discharge pressure of the oil pump 32 when driving the lift cylinder 10L with no load, for example. The area LD3 surrounded by the dashed line in FIG. 8 includes a plot of the discharge pressure of the oil pump 32 when driving only the tilt cylinder to tilt the fork. When the pressure of the lift cylinder 10L is less than a predetermined pressure threshold, the output control unit 63 may control the traveling output cutoff unit 47 so as not to cut off the transmission of the output from the traveling motor 41 to the driving wheel 10T, and may control the cooperative output cutoff unit 50 so as to cut off the transmission of the output from the traveling motor 41 to the loading output path 35 via the cooperative output path 54. As a result, the drive system 20 is set to a state in which the loading output path 35 and the traveling output path 44 operate independently of each other, as shown in FIG. 3.

[0074] [An example of computation processing by the control device 60] Next, an example of the calculation process by the control device 60 will be described. Fig. 9 and Fig. 10 are flow charts showing an example of the calculation process by the control device of Fig. 1. The control device 60 may have, for example, a loading priority mode and a traveling priority mode as modes selectable by the driver regarding the cooperation of the outputs of the loading motor 31 and the traveling motor 41. The loading priority mode is a mode in which the traveling motor 41 can use the cooperation to assist the loading motor 31. The traveling priority mode is a mode in which the loading motor 31 can use the cooperation to assist the traveling motor 41. The driver may be able to select the loading priority mode or the traveling priority mode via, for example, a switch or a touch panel provided at the driver's seat.

[0075] The process shown in Fig. 9 is executed when, for example, the loading priority mode is selected. As shown in Fig. 9, in S01, the control device 60 acquires the pressure of the lift cylinder 10L by the loading state acquisition unit 61. In S02, the control device 60 determines, by the output control unit 63, the load of the lift cylinder 10L equivalent to the discharge pressure shown as the solid line L2A in Fig. 8, for example, as the pressure threshold value of the lift cylinder 10L.

[0076] In S03, the control device 60 controls the loading output cutoff unit 38 by the output control unit 63 so as not to cut off the transmission of the output from the loading motor 31 to the oil pump 32. As a result, the output of the loading motor 31 is transmitted to the oil pump 32 via the loading output path 35.

[0077] In S04, the control device 60 determines whether the pressure of the lift cylinder 10L is equal to or greater than the pressure threshold value through the output control unit 63. When the control device 60 determines that the pressure of the lift cylinder 10L is equal to or greater than the pressure threshold value through the output control unit 63 (S04: YES), in S05, the control device 60 controls the traveling output cutoff unit 47 so as to cut off the transmission of the output from the traveling motor 41 to the driving wheel 10T through the output control unit 63. In S06, the control device 60 controls the cooperative output cutoff unit 50 so as not to cut off the transmission of the output from the traveling motor 41 to the loading output path 35 through the cooperative output path 54. As a result, the drive system 20 is set to a state in which the traveling motor 41 operates in cooperation with the loading motor 31 to assist it, as shown in FIG. 5. Thereafter, the control device 60 ends the process of FIG. 9 and repeats the process of FIG. 9 after a predetermined calculation period.

[0078] On the other hand, when the output control unit 63 determines that the pressure of the lift cylinder 10L is not equal to or higher than the pressure threshold (the pressure of the lift cylinder 10L is less than the pressure threshold) (S04: NO), the control device 60 controls the output control unit 63 to control the traveling output cutoff unit 47 so as not to cut off the transmission of the output from the traveling motor 41 to the drive wheels 10T in S07. In S08, the control device 60 controls the output control unit 63 to control the cooperative output cutoff unit 50 so as to cut off the transmission of the output from the traveling motor 41 to the loading output path 35 via the cooperative output path 54. As a result, the drive system 20 is set to a state in which the loading output path 35 and the traveling output path 44 operate independently, as shown in FIG. 3. Thereafter, the control device 60 ends the process of FIG. 9 and repeats the process of FIG. 9 after a predetermined calculation period.

[0079] The process shown in Fig. 10 is executed, for example, when the traveling priority mode is selected. As shown in Fig. 10, in S11, the control device 60 calculates (acquires) the wheel torque by the traveling state acquisition unit 62. The calculation of the wheel torque may take into account the vehicle speed of the forklift 10 and the weight of the load. In S12, the control device 60 determines a torque threshold value by the output control unit 63, for example, based on characteristics determined from the traveling motor 41 and gear requirements (e.g., gear ratio, etc.), as shown by the solid line L1B in Fig. 6. Alternatively, in S12, the control device 60 may determine a torque threshold value by the output control unit 63, for example, as shown by the dashed line Th1 in Fig. 7.

[0080] In S13, the control device 60 controls the driving output cut-off unit 47 by the output control unit 63 so as not to cut off the transmission of the output from the driving motor 41 to the driving wheels 10T. As a result, the output of the driving motor 41 is transmitted to the driving wheels 10T via the driving output path 44.

[0081] In S14, the control device 60 determines whether the wheel torque is equal to or greater than the torque threshold value by the output control unit 63. When the control device 60 determines that the wheel torque is equal to or greater than the torque threshold value by the output control unit 63 (S14: YES), in S15, the control device 60 controls the load output cutoff unit 38 by the output control unit 63 so as to cut off the transmission of the output from the load motor 31 to the oil pump 32. In S16, the control device 60 controls the cooperative output cutoff unit 50 by the output control unit 63 so as not to cut off the transmission of the output from the load motor 31 to the traveling output path 44 via the cooperative output path 54. As a result, the drive system 20 is set to a state in which the load motor 31 operates in cooperation with the traveling motor 41 to assist it, as shown in FIG. 4. Thereafter, the control device 60 ends the process of FIG. 10 and repeats the process of FIG. 10 after a predetermined calculation period.

[0082] On the other hand, when the output control section 63 judges that the wheel torque is not equal to or greater than the torque threshold (the wheel torque is less than the torque threshold) (S14: NO), the control device 60 controls the load output cutoff section 38 by the output control section 63 in S17 so as not to cut off the transmission of the output from the load motor 31 to the oil pump 32. In S18, the control device 60 controls the cooperative output cutoff section 50 by the output control section 63 so as to cut off the transmission of the output from the load motor 31 to the traveling output path 44 via the cooperative output path 54. As a result, the drive system 20 is set to a state in which the load output path 35 and the traveling output path 44 operate independently, as shown in FIG. 3. Thereafter, the control device 60 ends the process of FIG. 10 and repeats the process of FIG. 10 after a predetermined calculation period.

[0083] [Action and Effects] As described above, in the forklift 10 according to the present embodiment, the oil pump 32 does not necessarily require driving force, for example, during travel after a loading / unloading operation. Therefore, the load-unloading motor 31 can drive the driving wheel 10T instead of the oil pump 32 by cutting off the transmission of output from the load-unloading motor 31 to the oil pump 32 by the load-unloading output cutoff unit 38 and preventing the transmission of output from the load-unloading motor 31 to the traveling output path 44 via the cooperative output path 54 from being cut off by the cooperative output cutoff unit 50. As a result, the driving wheel 10T can be driven not only by the traveling motor 41 but also by the load-unloading motor 31, and the load-unloading motor 31 can be used for traveling. Therefore, the load-unloading motor 31 and the traveling motor 41 can be used efficiently compared to a case in which the usage of the load-unloading motor 31 and the traveling motor 41 is fixed to either traveling or loading / unloading.

[0084] The forklift 10 includes a traveling state acquisition unit 62 that acquires a wheel torque that drives the driving wheel 10T, and an output control unit 63 that controls the loading output cutoff unit 38 and the cooperative output cutoff unit 50 based on the wheel torque. When the wheel torque is equal to or greater than a predetermined torque threshold, the output control unit 63 controls the loading output cutoff unit 38 to cut off the transmission of output from the loading motor 31 to the oil pump 32, and controls the cooperative output cutoff unit 50 not to cut off the transmission of output from the loading motor 31 to the traveling output path 44 via the cooperative output path 54. This allows the output control unit 63 to automatically control whether the loading motor 31 drives the oil pump 32 or drives the driving wheel 10T instead of the oil pump 32 based on the wheel torque acquired by the traveling state acquisition unit 62.

[0085] In the forklift 10, for example, in a situation where loading and unloading work is performed while the forklift 10 is stopped, the driving wheel 10T does not necessarily require driving force. Therefore, the transmission of the output from the traveling motor 41 to the driving wheel 10T is cut off by the traveling output cutoff unit 47, and the transmission of the output from the traveling motor 41 to the loading and unloading output path 35 via the cooperative output path 54 is not cut off by the cooperative output cutoff unit 50, so that the traveling motor 41 can drive the oil pump 32 instead of the driving wheel 10T. As a result, the oil pump 32 is in a state in which it can be driven not only by the loading and unloading motor 31 but also by the traveling motor 41, and the traveling motor 41 can be used for loading and unloading. Therefore, the loading and unloading motor 31 and the traveling motor 41 can be used more efficiently than when the loading and unloading motors 31 and 41 are fixed to either one of traveling and loading and unloading.

[0086] The forklift 10 includes a hydraulic sensor 14 and a load-handling state acquisition unit 61 that acquire the pressure of the lift cylinder 10L for loading and unloading, and an output control unit 63 that controls the traveling output cutoff unit 47 and the cooperative output cutoff unit 50 based on the pressure of the lift cylinder 10L. When the pressure of the lift cylinder 10L is equal to or higher than a predetermined pressure threshold, the output control unit 63 controls the traveling output cutoff unit 47 to cut off the transmission of the output from the traveling motor 41 to the driving wheels 10T, and controls the cooperative output cutoff unit 50 not to cut off the transmission of the output from the traveling motor 41 to the loading and unloading output path 35 via the cooperative output path 54. This allows the output control unit 63 to automatically control the traveling output cutoff unit 47 and the cooperative output cutoff unit 50 to determine whether the traveling motor 41 drives the driving wheels 10T or drives the oil pump 32 instead of the driving wheels 10T based on the pressure of the lift cylinder 10L acquired by the hydraulic sensor 14 and the load-handling state acquisition unit 61.

[0087] The forklift 10 further includes an input shaft 33 connected to the output shaft of the cargo motor 31, and an input shaft 42 arranged adjacent to the input shaft 33 and connected to the output shaft of the travel motor 41. The cooperative output path 54 has a cooperative gear pair 51 provided between the input shaft 33 and the input shaft 42, and the cooperative output cutoff unit 50 is a hub sleeve 52 provided on the cooperative gear pair 51. As a result, the cargo motor 31 and the travel motor 41 can be made smaller by efficiently utilizing the outputs of the cargo motor 31 and the travel motor 41, and the cargo motor 31 and the travel motor 41 are adjacent to each other, so that the space of the drive system 20 can be saved. As a result, the freedom of layout of the cargo motor 31, the travel motor 41, and the drive system 20 in the forklift 10 can be improved.

[0088] [Variations] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

[0089] In the above embodiment, the running output path 44 has the running gear pair 45 (gears 45a, 45b) corresponding to one gear ratio, but is not limited to this example. The running output path 44 may have multiple running gear pairs corresponding to multiple gear ratios.

[0090] For example, as shown in Figs. 11 and 12, the running output path 44X may have a constantly meshing running gear pair 48 (gears 48a, 48b) as a running gear pair corresponding to two gear ratios in addition to the above-mentioned running gear pair 45 (gears 45a, 45b). In the example of Fig. 11, the running gear pair 48 corresponds to first gear, and the running gear pair 45 corresponds to second gear. The running gear pair 48 is provided with a hub sleeve 49. The gear 48b is journaled so as to be rotatable relative to the output shaft 43X, and can rotate independently of the output shaft 43X. The gear 48a is fixed to the input shaft 42X and rotates together with the input shaft 42X.

[0091] In the drive system 20X configured as above, as shown in FIG. 12, the rotation and torque of the input shaft 42X are transmitted to the gear 48b by the gear 48a rotating the gear 48b, and are transmitted to the output shaft 43X via the hub sleeve 49 when the hub sleeve 49 is engaged with the side surface of the gear 48b. That is, a traveling output path 44X including the input shaft 42X, the traveling gear pair 48 (gears 48a, 48b), the hub sleeve 49, and the output shaft 43X is formed between the traveling motor 41 and the driving wheel 10T. The traveling output cutoff unit 47X is the hub sleeves 46, 49 provided on each of the multiple traveling gear pairs 45, 48. According to this configuration, the vehicle speed range at which the forklift 10 can travel is expanded in accordance with the two gear ratios. In addition, the traveling output can be switched between being cut off and being cut off depending on whether the traveling gear pair 45, 48 and the hub sleeves 46, 49 are engaged with each other. In addition, the output control unit 63 of the control device 60 may transmit output from the traveling motor 41 to the driving wheel 10T via the traveling gear pair 45 corresponding to the second speed, for example, when the wheel rotation speed is equal to or higher than a predetermined value (for example, Th2 in FIG. 7).

[0092] In the above embodiment and modified example, the loading gear pair 36 is provided between the input shaft 33 and the output shaft 34, and the loading gear pair 36 is provided with the hub sleeve 37, but the present invention is not limited to this example. For example, as shown in FIG. 13, instead of the loading gear pair 36 (gears 36a, 36b) and the output shaft 34, the input shaft 33Y may drive the oil pump 32 via a clutch unit 37Y. The clutch unit 37Y may be, for example, a wet multi-plate clutch capable of cutting off the rotation and torque of the input shaft 33Y. In this configuration, a loading output path 35Y including the input shaft 33Y and the clutch unit 37Y is formed between the loading motor 31 and the oil pump 32. In this case, instead of the hub sleeve 37, the clutch unit 37Y functions as a loading output cutoff unit 38Y capable of cutting off the transmission of the output from the loading motor 31 to the oil pump 32.

[0093] The load gear pair 36, the running gear pair 45, and the linking gear pair 51 are not limited to the constant meshing type.

[0094] In the above embodiment and modified example, the hub sleeve 46 functions as the driving output cut-off unit 47 capable of cutting off the transmission of the output from the driving motor 41 to the drive wheels 10T, but is not limited to this example. For example, a synchronizer ring of a transmission used in passenger cars or the like may be interposed between the side surface of the hub sleeve and the side surface of a gear or the like. Alternatively, the hub sleeve may be of a dog clutch type in which no synchronizer ring is interposed.

[0095] Also, for example, as shown in FIG. 14, instead of the hub sleeve 46, a clutch unit 46Z functioning as a traveling output cutoff unit 47Z may be provided. The clutch unit 46Z may be, for example, a wet multi-plate clutch capable of cutting off the rotation and torque of the input shaft 42Z. In the example of FIG. 14, the rotation and torque of the input shaft 42Z are transmitted to the gear 55b by the gear 55a rotating the gear 55b, and are transmitted to the input shaft 33Z via the hub sleeve 52Z in a state in which the hub sleeve 52Z is ​​engaged with the side surface of the gear 55b. Conversely, the rotation and torque of the input shaft 33Z are transmitted to the gear 55b via the hub sleeve 52Z in a state in which the hub sleeve 52Z is ​​engaged with the side surface of the gear 55b. The rotation and torque of the input shaft 33Z are transmitted to the gear 55a by the gear 55b rotating the gear 55a, and are transmitted to the input shaft 42Z. That is, between the load output path 35Z and the traveling output path 44Z, a linking output path 54Z is formed, which includes the input shaft 42Z, the linking gear pair 55Z (gears 55a, 55b), the hub sleeve 52Z, and the input shaft 33Z. Note that instead of the configuration in which the hub sleeve 52Z on the input shaft 33Z side engages with the side surface of the gear 55b, a configuration in which a hub sleeve that engages with the side surface of the gear 55a is provided on the input shaft 42Z side may be used. Note that a gear rotatably supported on an idler shaft may be provided between the gears 55a and 55b as appropriate.

[0096] In the above embodiment, the output control unit 63 automatically controls whether the loading motor 31 drives the oil pump 32 or drives the drive wheel 10T instead of the oil pump 32 based on the wheel torque acquired by the traveling state acquisition unit 62, but the present invention is not limited to this example. For example, the loading output cutoff unit 38 may be manually operated by the driver using a wire that moves the hub sleeve 37 so as to cut off the transmission of output from the loading motor 31 to the oil pump 32. The driver may manually operate the cooperative output cutoff unit 50 using a wire that moves the hub sleeve 52 so as not to cut off the transmission of output from the loading motor 31 to the traveling output path 44 via the cooperative output path 54.

[0097] In the above embodiment, the output control unit 63 automatically controls the traveling output cutoff unit 47 and the cooperative output cutoff unit 50 to determine whether the traveling motor 41 drives the driving wheels 10T or drives the oil pump 32 instead of the driving wheels 10T based on the pressure of the lift cylinder 10L acquired by the hydraulic sensor 14 and the loading state acquisition unit 61, but this is not limiting. For example, the traveling output cutoff unit 47 may be manually operated by the driver using a wire that moves the hub sleeve 46 to cut off the transmission of output from the traveling motor 41 to the driving wheels 10T. The cooperative output cutoff unit 50 may be manually operated by the driver using a wire that moves the hub sleeve 52 to prevent the transmission of output from the traveling motor 41 to the loading output path 35 via the cooperative output path 54.

[0098] 9 (determination of the pressure threshold value) and the process of S12 in the flowchart of FIG. 10 (determination of the torque threshold value) do not have to be performed while the forklift 10 is in operation. The pressure threshold value and the torque threshold value may be determined in advance at the design stage of the forklift 10 and stored in the control device 60.

[0099] In the above embodiment, the forklift 10 is exemplified as an industrial vehicle, but the present invention is not limited to this. The industrial vehicle may be any vehicle that includes a plurality of electric motors as a drive source for multiple purposes such as traveling and loading and unloading.

[0100] At least some of the embodiments and various modified examples described above may be combined in any desired manner. [Explanation of symbols]

[0101] 10...Forklift (industrial vehicle), 10T...Drive wheel (wheel), 10L...Lift cylinder, 14...Hydraulic sensor (pressure acquisition unit), 31...Loading motor (first electric motor), 32...Oil pump, 33...Input shaft (first shaft), 35, 35Y, 35Z...Loading output path, 37, 46, 49, 52, 52Z...Hub sleeve, 38, 38Y...Loading output cut-off unit, 41...Travel motor ( second electric motor), 42...input shaft (second shaft), 44, 44X, 44Z...driving output path, 45, 48...driving gear pair, 47, 47X, 47Z...driving output cut-off section, 50...coordinated output cut-off section, 51, 55Z...coordinated gear pair, 54, 54Z...coordinated output path, 61...loading state acquisition section (pressure acquisition section), 62...driving state acquisition section (torque acquisition section), 63...output control section (cut-off control section).

Claims

1. An industrial vehicle including a first motor and a second motor, a cargo handling output path formed between the first electric motor and a cargo handling oil pump; a driving output path formed between the second electric motor and wheels; A linking output path formed between the loading output path and the traveling output path; a loading output cut-off unit capable of cutting off transmission of output from the first electric motor to the oil pump; a link output cut-off unit capable of cutting off transmission of output via the link output path, an output cut-off unit for cutting off the transmission of output from the first electric motor to the driving output path via the output cut-off path when the transmission of output from the first electric motor to the oil pump is cut off by the loading / unloading output cut-off unit;

2. a torque acquisition unit that acquires a wheel torque that drives the wheel; a cutoff control unit that controls the loading output cutoff unit and the cooperative output cutoff unit based on the wheel torque, 2. The industrial vehicle according to claim 1, wherein the cut-off control unit controls the loading output cut-off unit so as to cut off transmission of output from the first electric motor to the oil pump when the wheel torque is equal to or greater than a predetermined torque threshold, and controls the cooperative output cut-off unit so as not to cut off transmission of output from the first electric motor to the driving output path via the cooperative output path.

3. An industrial vehicle including a first motor and a second motor, a cargo handling output path formed between the first electric motor and a cargo handling oil pump; a driving output path formed between the second electric motor and wheels; A linking output path formed between the loading output path and the traveling output path; a traveling output cut-off unit capable of cutting off transmission of output from the second electric motor to the wheels; a link output cut-off unit capable of cutting off transmission of output via the link output path, The cooperative output cut-off unit does not cut off the transmission of output from the second motor to the loading output path via the cooperative output path when the transmission of output from the second motor to the wheels is cut off by the driving output cut-off unit.

4. A pressure acquisition unit that acquires a pressure of a lift cylinder for loading and unloading; A cutoff control unit that controls the traveling output cutoff unit and the cooperative output cutoff unit based on the pressure, 4. The industrial vehicle according to claim 3, wherein the cut-off control unit controls the driving output cut-off unit so as to cut off transmission of output from the second electric motor to the wheels when the pressure is equal to or greater than a predetermined pressure threshold, and controls the cooperative output cut-off unit so as not to cut off transmission of output from the second electric motor to the loading output path via the cooperative output path.

5. the driving output path has a plurality of driving gear pairs corresponding to a plurality of gear ratios, 5. The industrial vehicle according to claim 3, wherein the driving output cutoff portion is a hub sleeve provided on each of the plurality of driving gear pairs.

6. a first shaft connected to an output shaft of the first electric motor; a second shaft disposed adjacent to the first shaft and connected to an output shaft of the second motor, the cooperative output path includes a cooperative gear pair provided between the first shaft and the second shaft, The industrial vehicle according to any one of claims 1 to 5, wherein the coordination output cutoff portion is a hub sleeve provided on the coordination gear pair.

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