JP7619249B2 - Industrial Vehicles - Google Patents

Description

The present invention relates to an industrial vehicle.

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.

JP 2011-79637 A

In recent years, for example in the field of automobile technology, electric vehicles that run only on electric motors without internal combustion engines have been popularized from the viewpoint of environmental protection. The application of such replacement of internal combustion engines with electric motors to the technical field of industrial vehicles such as forklifts is also being considered. However, while the output characteristics of the drive sources required for driving and loading/unloading in industrial vehicles such as forklifts are different, there are also differences in the individual output characteristics of internal combustion engines and electric motors. Therefore, simply replacing one internal combustion engine with one electric motor would likely lead to an increase in the size of the electric motor in order to obtain the same performance as an internal combustion engine for driving and loading/unloading, which would likely result in inefficiency.

For these reasons, it is conceivable to provide a configuration in which one electric motor is provided independently 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, even though there are only a limited number of situations in which both driving performance and loading and unloading performance are required at the same time, it is necessary to ensure sufficient driving performance with the driving motor and sufficient loading and unloading performance with the loading and unloading motor. As a result, it tends to be difficult to utilize each electric motor efficiently.

The present invention aims to provide an industrial vehicle that can utilize multiple electric motors more efficiently than when the purpose of each electric motor is fixed to either traveling or loading and unloading.

An industrial vehicle according to one aspect 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 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 loading output cutoff unit capable of cutting off the transmission of output from the first electric motor to the oil pump, and a linked output cutoff 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 cutoff unit, the linked output cutoff unit does not cut off the transmission of output from the first electric motor to the driving output path via the linked output path.

In an industrial vehicle according to one aspect of the present invention, for example, when traveling after loading and unloading work, the oil pump does not necessarily require driving force. Therefore, by blocking the transmission of output from the first electric motor to the oil pump by the loading and unloading output blocking unit and preventing the transmission of output from the first electric motor to the traveling output path via the linked output path by the linked output blocking unit, the first electric motor can drive the wheels instead of the oil pump. As a result, the wheels 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.

In one embodiment, the vehicle includes a torque acquisition unit that acquires 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. When the wheel torque is equal to or greater than a predetermined torque threshold, the cutoff control unit controls the loading output cutoff unit to cut off the transmission of output from the first electric motor to the oil pump, and may control the linked output cutoff unit not to cut off the transmission of output from the first electric motor to the driving 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.

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 is equipped with 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 cutoff unit capable of cutting off the transmission of output from the second electric motor to the wheels, and a linked output cutoff 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 cutoff unit, the linked output cutoff unit does not cut off the transmission of output from the second electric motor to the loading output path via the linked output path.

In an industrial vehicle according to another aspect of the present invention, for example, in a situation where loading and unloading work is being performed while the vehicle is stopped, the wheels do not necessarily require driving force. Therefore, by blocking the transmission of output from the second motor to the wheels by the driving output blocking unit and preventing the transmission of output from the second motor to the loading and unloading output path via the linked output path by the linked output blocking unit, 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.

In one embodiment, the device 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 driving output cutoff unit and the linked output cutoff unit based on the pressure of the lift cylinder. When the pressure of the lift cylinder is equal to or greater than a predetermined pressure threshold, the cutoff control unit controls the driving output cutoff unit to cut off the transmission of output from the second electric motor to the wheels, and may also 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 driving 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.

In one embodiment, the driving output path has 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 on 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 response to the plurality of gear ratios. In addition, the driving output can be switched between being cut off and not being cut off depending on whether the driving gear pair is engaged with the hub sleeve.

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, efficient use of multiple motors allows for a reduction in size of the motors, and space can be saved. As a result, the freedom of layout in the industrial vehicle can be improved.

The present invention makes it possible to utilize multiple electric motors more efficiently than when each motor is fixed to either travel or loading/unloading.

1 is a block diagram showing a schematic configuration of an industrial vehicle according to an embodiment; FIG. 2 is a schematic diagram showing an example of a drive system of the industrial vehicle shown in FIG. 1 . 3 is a diagram showing a state in which the transmission of output through a link output path in the drive system of FIG. 2 is interrupted. FIG. 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-handling output cut-off unit in the drive system of FIG. 2, and the transmission of output from the first electric motor to the driving output path via the linked output path is not cut off. FIG. 3 is a diagram showing a state in which the transmission of output from the second 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 motor to the loading output path via the linked output path is not interrupted. FIG. 4 is a diagram illustrating an example of a relationship between wheel torque and wheel rotation speed. FIG. 7 is a diagram for explaining a predetermined travel of the industrial vehicle in FIG. 6 . 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. 2 is a flowchart showing an example of a calculation process performed by the control device of FIG. 1 . 2 is a flowchart showing an example of a calculation process performed by the control device of FIG. 1 . FIG. 13 is a schematic diagram showing a modified example of the drive system of the industrial vehicle. 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-handling 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. FIG. 13 is a schematic diagram showing another modified example of the drive system of the industrial vehicle. FIG. 13 is a schematic diagram showing still another modified example of the drive system of the industrial vehicle.

Embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, identical or equivalent elements are given the same reference numerals, and duplicate descriptions will be omitted.

Figure 1 is a block diagram showing the schematic configuration of an industrial vehicle according to one embodiment. Figure 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 (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 instead of an internal combustion engine on a machine base that would conventionally be equipped with an internal combustion engine.

The forklift 10 has, 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.

The forklift 10 is equipped with a loading device. The loading device may be provided forward when viewed from the driver's seat. The loading device has a mast, a lift cylinder 10L, a tilt cylinder, and a fork.

The forklift 10 may be equipped with 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 up and down. 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 up and down, 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 forward and backward, adjusting the tilt angle of the loading device.

The forklift 10 is equipped with a drive system 20. The drive system 20 is a device for transmitting the power generated by the motor to the wheels, etc. The drive system 20 has a loading drive system 30 and a traveling drive system 40.

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

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 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.

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 the load loaded on the forklift.

The traveling drive system 40 is a power train that generates a driving force to drive the driving wheels 10T to make the forklift 10 travel. 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 that mainly drives the driving wheels 10T.

When the driver operates the accelerator pedal 12, the driving motor 41 rotates at a speed that corresponds to the amount of operation of the accelerator pedal 12. The driving system 40 also includes a steering mechanism that steers the rear wheels based on the operation of the steering wheel 13.

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 is equipped with 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.

Figure 2 is a schematic diagram showing an example of the drive system of the industrial vehicle of Figure 1. As shown in Figure 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 the 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.

A loading output path 35 is formed between the loading motor 31 and the oil pump 32. The input shaft 33 is connected to 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, but the output shaft 34 and the oil pump 32 may be indirectly connected by providing, for example, a joint between the output shaft 34 and the oil pump 32.

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

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 can move toward or away from the gear 36a of the loading gear pair 36 along the input shaft 33. On the gear 36a side of the hub sleeve 37, multiple protrusions are formed to correspond to multiple projections and recesses on the side of the gear 36a. The hub sleeve 37 can engage with the side of the gear 36a.

The rotation and torque of the input shaft 33 is transmitted to the gear 36a via the hub sleeve 37 when the hub sleeve 37 is engaged with the side of the gear 36a. When the gear 36a rotates the gear 36b, the rotation and torque of the input shaft 33 is 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.

When the hub sleeve 37 moves away from the gear 36a and is no longer engaged with the side of the gear 36a, it 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 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 does not engage with the side of the gear 36a, the transmission of output from the loading motor 31 to the oil pump 32 is cut off. Here, the hub sleeve 37 functions as a loading output cutoff unit 38 that can cut off the transmission of output from the loading motor 31 to the oil pump 32.

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

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

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 can move toward or away from the gear 45b of the running gear pair 45 along the output shaft 43. On the gear 45b side of the hub sleeve 46, multiple protrusions are formed to correspond to multiple projections and recesses on the side of the gear 45b. The hub sleeve 46 can engage with the side of the gear 45b.

The rotation and torque of the input shaft 42 is transmitted to the gear 45b by the gear 45a rotating the gear 45b, and is transmitted to the output shaft 43 via the hub sleeve 46 when the hub sleeve 46 is engaged with the side 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.

When the hub sleeve 46 moves away from the gear 45b and is no longer engaged with the side 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 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 does not engage with the side of the gear 45b, the transmission of the output from the travel motor 41 to the drive wheels 10T is cut off. Here, the hub sleeve 46 functions as a travel output cut-off unit 47 that can cut off the transmission of the output from the travel motor 41 to the drive wheels 10T.

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 loading 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 loading motor 31 and the traveling motor 41.

Between the input shaft 33 and the input shaft 42, a constantly meshing pair of interlocking gears 51 is provided. A hub sleeve 52 is provided in the pair of interlocking gears 51. The pair of interlocking gears 51 is a pair of gears 45a, 53 that have a diameter dimension that results in a predetermined gear 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.

The diameter of gear 45a is, for example, smaller than the diameter of gear 53. The linking gear pair 51 has a gear ratio that reduces the rotation speed of the traveling motor 41 and transmits it 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.

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 can move toward or away from the gear 53 of the interlocking gear pair 51 along the input shaft 33. A number of protrusions are formed on the gear 53 side of the hub sleeve 52 so as to correspond to a number of irregularities provided on the side of the gear 53. The hub sleeve 52 can engage with the side of the gear 53.

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 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 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, between the loading output path 35 and the traveling output path 44, a linking output path 54 is formed, which includes the input shaft 42, the linking gear pair 51 (gears 45a, 53), the hub sleeve 52, and the input shaft 33.

When the hub sleeve 52 moves away from the gear 53 and is no longer engaged with the side 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 of the gear 53, the transmission of output via the linked output path 54 is cut off. In other words, the hub sleeve 52 here functions as a linked output cut-off unit 50 that can cut off the transmission of output via the linked output path 54. The linked output cut-off unit 50 here is the hub sleeve 52 provided on the linked gear pair 51.

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 linked 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 of the gear 36a, the hub sleeve 46 is engaged with the side of the gear 45b, and the hub sleeve 52 is not engaged with the side 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 linked output path 54 is interrupted.

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.

Figure 4 shows the state in the drive system of Figure 2 where the load output cutoff unit cuts off the transmission of output from the first motor to the oil pump, but the transmission of output from the first motor to the traveling output path via the linked output path is not cut off. In the example of Figure 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 linked output path 54 is not cut off.

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.

Figure 5 is a diagram showing a state in the drive system of Figure 2 where 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 linked output path is not interrupted. In the example of Figure 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 wheel 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 linked output path 54 is not interrupted.

In this case, the travel 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 travel motor 41 is further transmitted to the loading output path 35 via the cooperative output path 54. The output of the travel 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 that engages with the gear 53, and is transmitted to the loading output path 35. As a result, the output of the travel motor 41 is transmitted to the loading output path 35 via the cooperative output path 54, while the output of the loading motor 31 is not transmitted to the travel output path 44.

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 loading and unloading operation lever 11 and the accelerator pedal 12.

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.

The control device 60 is electrically connected to the loading 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.

Next, the functional configuration of the control device 60 will be described. 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.

The loading status acquisition unit 61 acquires the status (load) of the loading device. The status of the loading device is obtained from 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.

The running state acquisition unit 62 acquires the state of the drive wheel 10T as the running state of the forklift 10. The state of the drive wheel 10T includes the wheel torque and the wheel rotation speed. The running state acquisition unit 62 can calculate the wheel torque that drives the drive wheel 10T, for example, using a known conversion formula 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 drive wheel 10T. The value of the wheel torque may change prior to the actual driving torque of the drive wheel 10T, or may represent a target value of the driving force of the drive wheel 10T. The running state acquisition unit 62 can calculate the wheel rotation speed, for example, using a known conversion formula based on the rotation speed of the travel motor 41.

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 that the number of rotations corresponds 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 that the number of rotations corresponds 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.

[Coordination in which the cargo handling motor assists the travel motor]
The output control unit 63 can control the loading output cut-off unit 38 and the cooperative output cut-off unit 50 based on the wheel torque.

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, the 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.

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

During a given run, when an empty 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, the upper limit torque value that can be taken on the low vehicle speed side of the travel 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 aligned with the coordinate system of FIG. 6 (the vehicle speed at the right end of the dashed line L1A).

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 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 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, the value shown as the solid line L1B in FIG. 6. The torque threshold may be set to the value shown as the 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.

The dashed-dotted line DR2 in FIG. 7 is an example of the trajectory of the state of the drive wheels 10T in a driving pattern in which the forklift 10 starts moving and increases its vehicle speed. Of the dashed-dotted line DR2, the dashed-dotted line DR2a, which is the portion where the wheel rotation speed rises from the point where it is 0, corresponds to the time when the forklift 10 starts moving.

When the forklift 10, which has lifted a load using the loading device, starts to travel, 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 the torque threshold. Therefore, when the wheel torque is equal to or greater than a predetermined torque threshold, the output control unit 63 may control the loading output cutoff unit 38 to cut off the transmission of output from the loading motor 31 to the oil pump 32, and control the linked 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 linked output path 54. In other words, when the transmission of output from the loading motor 31 to the oil pump 32 is cut off by the loading output cutoff unit 38, the linked output cutoff unit 50 does not cut off the transmission of output from the loading motor 31 to the traveling output path 44 via the linked 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 cooperation 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 FIG. 6 and FIG. 7, the driving force of the driving wheel 10T can be realized within a range whose upper limit is the solid line L1C.

Note that the dashed-dotted line DR2b in FIG. 7, which is on the high vehicle speed side from the apex, corresponds to a situation in which the vehicle speed of the forklift 10 increases when the loading device is used to lift a load, and the acceleration becomes slower 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 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.

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

8 is a diagram showing an example of the relationship between the discharge pressure and the flow rate of the oil pump. The horizontal axis of FIG. 8 is the discharge flow rate of the oil pump 32, which increases or decreases depending on 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 travel 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 travel motor 41. The solid line L2A and dashed line L2B are determined by the characteristics of the loading motor 31, the travel motor 41, and the oil pump 32 mounted on the forklift 10. Each plot in FIG. 8 is the 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 where the operating point of lift and/or tilt operations with or without load is located relative to the output of the oil pump 32. Area LD1 shows the case where lift operations are performed with maximum load. Area LD2 shows the case where lift operations are performed with no load. Area LD3 shows the case where only tilt operations are performed with maximum load and with no load.

In Figure 8, when the load is increased from the unloaded region LD2, there is a boundary between the region LD2 and the maximum load region LD1, where the output from the loading motor 31 alone is insufficient. This boundary is the upper limit pressure value when the oil pump 32 is driven by the loading motor 31 alone, and corresponds to the solid line L2A in Figure 8.

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 greater than the predetermined pressure threshold, the output control unit 63 may control the traveling output cutoff unit 47 to cut off the transmission of output from the travel motor 41 to the drive wheels 10T, and may control the coordinated output cutoff unit 50 not to cut off the transmission of output from the travel motor 41 to the load output path 35 via the coordinated output path 54. In other words, when the transmission of output from the travel motor 41 to the drive wheels 10T is cut off by the travel output cutoff unit 47, the coordinated output cutoff unit 50 does not cut off the transmission of output from the travel motor 41 to the load output path 35 via the coordinated output path 54. The predetermined pressure threshold is a pressure threshold for determining whether the travel motor 41 operates in coordination to assist the load motor 31. By setting such a pressure threshold, each plot (e.g., area LD1) of the discharge pressure when the lift cylinder 10L is driven under high load will be included in the range with the solid line L2C as the upper limit. Note that if the travel motor 41 is switched to assist the loading motor 31 while traveling, sudden deceleration may occur, so it is desirable to limit the assistance of the loading motor 31 by the travel motor 41 to cases where the traveling function is not required.

As a result, the drive system 20 is set to a state in which the travel motor 41 operates in cooperation with the loading motor 31 to assist it, as shown in FIG. 5. Since the output of the travel motor 41 is transmitted to the loading output path 35 via the cooperative output path 54, the discharge pressure of the oil pump 32 can be realized by adding the output of the travel 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.

When the pressure of the lift cylinder 10L above the pressure threshold is no longer required, the link between the travel motor 41 and the load motor 31 is released. As shown in FIG. 3, the drive system 20 is set to a state in which the load output path 35 and the travel output path 44 operate independently.

Note that 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 driving output cutoff unit 47 so as not to cut off the transmission of output from the travel motor 41 to the drive wheel 10T, and may also control the linked output cutoff unit 50 to cut off the transmission of output from the travel motor 41 to the load output path 35 via the linked output path 54. As a result, the drive system 20 is set to a state in which the load output path 35 and the travel output path 44 operate independently, as shown in FIG. 3.

[An example of arithmetic processing by the control device 60]
Next, an example of the calculation process by the control device 60 will be described. Figures 9 and 10 are flow charts showing an example of the calculation process by the control device of Figure 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.

The process shown in FIG. 9 is executed, for example, when 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 using the loading status acquisition unit 61. In S02, the control device 60 determines, using the output control unit 63, the load of the lift cylinder 10L that corresponds 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.

In S03, the control device 60 controls the load output cutoff unit 38 via the output control unit 63 so as not to cut off the transmission of output from the load motor 31 to the oil pump 32. This causes the output of the load motor 31 to be transmitted to the oil pump 32 via the load output path 35.

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

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

The process shown in FIG. 10 is executed, for example, when the driving priority mode is selected. As shown in FIG. 10, in S11, the control device 60 calculates (acquires) the wheel torque by the driving 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 the torque threshold value by the output control unit 63, for example, based on the characteristics determined from the driving motor 41 and the 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 the torque threshold value by the output control unit 63, for example, as shown by the dashed line Th1 in FIG. 7.

In S13, the control device 60 controls the driving output cutoff unit 47 by the output control unit 63 so as not to cut off the transmission of output from the driving motor 41 to the drive wheels 10T. This causes the output of the driving motor 41 to be transmitted to the drive wheels 10T via the driving output path 44.

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

On the other hand, if the output control unit 63 determines 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 unit 60 controls the load output cutoff unit 38 in S17 so as not to cut off the transmission of output from the load motor 31 to the oil pump 32 by the output control unit 63. In S18, the control unit 60 controls the linked output cutoff unit 50 in S18 so as to cut off the transmission of output from the load motor 31 to the traveling output path 44 via the linked 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. The control unit 60 then ends the process of FIG. 10 and repeats the process of FIG. 10 after a predetermined calculation period.

[Action and Effect]
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 motor 31 can drive the driving wheel 10T instead of the oil pump 32 by blocking the transmission of output from the load motor 31 to the oil pump 32 by the load output blocking unit 38 and preventing the transmission of output from the load motor 31 to the travel output path 44 via the linked output path 54 from being blocked by the linked output blocking unit 50. As a result, the driving wheel 10T can be driven not only by the travel motor 41 but also by the load motor 31, and the load motor 31 can be used for travel. Therefore, compared with a case in which the load motor 31 and the travel motor 41 are fixed to either travel or load unloading, the load motor 31 and the travel motor 41 can be used efficiently.

The forklift 10 includes a driving state acquisition unit 62 that acquires the wheel torque that drives the drive wheels 10T, and an output control unit 63 that controls the loading output cutoff unit 38 and the linked 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 linked output cutoff unit 50 not to cut off the transmission of output from the loading motor 31 to the driving output path 44 via the linked 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 drive wheels 10T instead of the oil pump 32 based on the wheel torque acquired by the driving state acquisition unit 62.

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

The forklift 10 includes a hydraulic sensor 14 and a loading status 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 driving output cutoff unit 47 and the linked 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 driving output cutoff unit 47 to cut off the transmission of output from the travel motor 41 to the drive wheels 10T, and controls the linked output cutoff unit 50 not to cut off the transmission of output from the travel motor 41 to the load output path 35 via the linked output path 54. This allows the output control unit 63 to automatically control the driving output cutoff unit 47 and the linked output cutoff unit 50 to determine whether the travel motor 41 drives the drive wheels 10T or drives the oil pump 32 instead of the drive wheels 10T based on the pressure of the lift cylinder 10L acquired by the hydraulic sensor 14 and the loading status acquisition unit 61.

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

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

In the above embodiment, the running output path 44 has a 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.

11 and 12, the running output path 44X may have a constantly meshing running gear pair 48 (gears 48a, 48b) in addition to the running gear pair 45 (gears 45a, 45b) as a running gear pair corresponding to two gear ratios. 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.

In the drive system 20X configured in this manner, 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 through the hub sleeve 49 when the hub sleeve 49 is engaged with the side of the gear 48b. That is, between the travel motor 41 and the drive wheel 10T, a travel output path 44X is formed, which includes the input shaft 42X, the travel gear pair 48 (gears 48a, 48b), the hub sleeve 49, and the output shaft 43X. The travel output cutoff section 47X is the hub sleeves 46, 49 provided on each of the multiple travel gear pairs 45, 48. According to this configuration, the vehicle speed range at which the forklift 10 can travel is expanded in response to the two gear ratios. In addition, the travel output can be switched between being cut off and not being cut off depending on whether the travel gear pairs 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 the output from the driving motor 41 to the drive wheel 10T via the driving gear pair 45 corresponding to the second speed when the wheel rotation speed is equal to or greater than a predetermined value (e.g., Th2 in FIG. 7).

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 a hub sleeve 37, but this is not limited to the 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 the 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 cut-off unit 38Y capable of cutting off the transmission of the output from the loading motor 31 to the oil pump 32.

Note that the loading gear pair 36, the running gear pair 45, and the interlocking gear pair 51 are not limited to being of the constant meshing type.

In the above embodiment and modified example, the hub sleeve 46 functions as a driving output cut-off section 47 that can cut off the transmission of 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 of the hub sleeve and the side of a gear or the like. Alternatively, the hub sleeve may be of a dog clutch type that does not have a synchronizer ring.

Also, for example, as shown in FIG. 14, instead of the hub sleeve 46, a clutch unit 46Z that functions as a driving output cutoff unit 47Z may be provided. The clutch unit 46Z may be, for example, a wet multi-plate clutch that can cut 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 when the hub sleeve 52Z is engaged with the side 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 when the hub sleeve 52Z is engaged with the side 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 travel output path 44Z, an input shaft 42Z, an interlocking gear pair 55Z (gears 55a, 55b), a hub sleeve 52Z, and an interlocking output path 54Z including the input shaft 33Z. Note that instead of a configuration in which the hub sleeve 52Z on the input shaft 33Z side engages with the side of the gear 55b, a configuration in which a hub sleeve that engages with the side 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.

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 driving state acquisition unit 62, but this is not limited to the 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 to cut off the transmission of output from the loading motor 31 to the oil pump 32. The driver may manually operate the linked output cutoff unit 50 using a wire that moves the hub sleeve 52 to not cut off the transmission of output from the loading motor 31 to the driving output path 44 via the linked output path 54.

In the above embodiment, the output control unit 63 automatically controls the driving output cutoff unit 47 and the linked output cutoff unit 50 to determine whether the driving motor 41 drives the drive wheels 10T or drives the oil pump 32 instead of the drive 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 limited to the example. For example, the driving 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 driving motor 41 to the drive wheels 10T. The linked 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 driving motor 41 to the loading output path 35 via the linked output path 54.

The process of S02 in the flowchart of FIG. 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 determination of 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.

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 equipped with multiple electric motors as a drive source for multiple purposes, such as traveling and loading and unloading.

At least some of the embodiments and various modified examples described above may be combined in any manner.

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 cutoff unit, 41...Travel motor (second electric motor), 42...Input shaft (second shaft), 44, 44X, 44Z...Traveling output path, 45, 48...Traveling gear pair, 47, 47X, 47Z...Traveling output cutoff unit, 50...Cooperation output cutoff unit, 51, 55Z...Cooperation gear pair, 54, 54Z...Cooperation output path, 61...Loading state acquisition unit (pressure acquisition unit), 62...Traveling state acquisition unit (torque acquisition unit), 63...Output control unit (cutoff control unit).

Claims (6)

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; 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. 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. 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. 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. 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.

Images