JP6784074B2 - Pressure booster for aerial work platforms - Google Patents

Description

The present invention relates to a pressure booster for aerial work platforms.

Conventionally, aerial work platforms equipped with a bucket at the tip of the boom have been known. In the aerial work platform, the hydraulic hose is guided to the bucket, and hydraulic oil can be supplied to the hydraulic tools connected to the hydraulic hose. Such aerial work platforms are provided with a pressure booster to increase the pressure of the hydraulic oil sent to the hydraulic tool (see, for example, Patent Document 1).

The pressure boosting device includes a pressure boosting cylinder, a filling oil passage that guides hydraulic oil to the pressure boosting chamber of the pressure booster cylinder, and a pressure booster oil passage that guides hydraulic oil to the oil chamber on the forward side of the pressure booster cylinder. It is provided with a pressure reducing oil passage for guiding the hydraulic oil to the oil chamber on the return side of the pressure cylinder and an electromagnetic switching valve for guiding the hydraulic oil to the pressure increasing oil passage or the pressure reducing oil passage. Then, when the electromagnetic switching valve guides the hydraulic oil to the pressure boosting oil passage, the hydraulic oil is pushed out from the pressure boosting chamber to increase the pressure of the hydraulic oil sent to the hydraulic tool, and the electromagnetic switching valve sends the hydraulic oil to the pressure reducing oil passage. When guided, the hydraulic oil is drawn into the pressure boosting chamber and the hydraulic oil sent to the hydraulic tool can be depressurized.

By the way, in such a pressure booster, if the operating speed of the hydraulic tool can be arbitrarily selected, it is possible to improve the work efficiency or reduce the energy consumption. That is, if the operating speed of the hydraulic tool is appropriately increased, the work efficiency can be improved, and if the operating speed of the hydraulic tool is appropriately reduced, energy consumption can be reduced. In particular, when the hydraulic oil pump is operated by a motor, it is possible to reduce power consumption by appropriately slowing down the operating speed of the hydraulic tool. In addition, even if the drive source for operating the hydraulic oil pump and its rotation speed can be arbitrarily selected, it is considered that improvement of work efficiency or reduction of energy consumption can be realized. Therefore, there has been a demand for a pressure booster capable of selecting one mode from a plurality of modes.

However, in such a pressure booster, when the amount of hydraulic oil delivered by the hydraulic oil pump increases according to the selected mode, the amount of hydraulic oil guided to the forward oil chamber increases and is pushed out of the pressure booster chamber. Since the amount of hydraulic oil to be discharged increases, the maximum pressure of hydraulic oil sent to the hydraulic tool becomes higher than the target value. On the contrary, when the amount of hydraulic oil delivered by the hydraulic oil pump decreases according to the selected mode, the amount of hydraulic oil guided to the forward oil chamber decreases and the amount of hydraulic oil pushed out from the booster chamber also decreases. The maximum pressure of hydraulic oil sent to the hydraulic tool becomes lower than the target value. That is, if the amount of hydraulic oil delivered by the hydraulic oil pump changes according to the selected mode, the maximum pressure of the hydraulic oil sent to the hydraulic tool will differ. Therefore, there has been a demand for a pressure booster capable of keeping the maximum pressure of hydraulic oil sent to the hydraulic tool constant even if the amount of hydraulic oil delivered by the hydraulic oil pump changes.

Japanese Unexamined Patent Publication No. 2014-20543

One mode can be selected from multiple modes, and the maximum pressure of hydraulic oil sent to the hydraulic tool can be kept constant even if the amount of hydraulic oil delivered by the hydraulic oil pump changes. Provide the device.

The problem to be solved by the present invention is as described above, and next, the means for solving this problem will be described.

The first invention is
Booster cylinder and
A filling oil passage that guides hydraulic oil to the boosting chamber of the boosting cylinder, and
A booster oil passage that guides hydraulic oil to the oil chamber on the forward side of the booster cylinder,
A decompression oil passage that guides hydraulic oil to the oil chamber on the return side of the booster cylinder, and
An electromagnetic switching valve for guiding hydraulic oil to the pressure increasing oil passage or the pressure reducing oil passage is provided.
When the electromagnetic switching valve guides the hydraulic oil to the pressure boosting oil passage, the hydraulic oil is pushed out from the pressure boosting chamber and the hydraulic oil sent to the hydraulic tool can be boosted.
In a pressure booster for aerial work platforms, when the electromagnetic switching valve guides the hydraulic oil to the pressure reducing oil passage, the hydraulic oil is drawn into the pressure boosting chamber and the hydraulic oil sent to the hydraulic tool can be depressurized.
A mode selection unit is provided so that the operator can manually select the operation mode .
A pressure sensor that detects the pressure of hydraulic oil sent to the hydraulic tool, and
A controller that controls the electromagnetic switching valve while recognizing the pressure transition of the hydraulic oil based on the signal from the pressure sensor is provided.
The controller sets a threshold value according to the selection status of the mode selection unit, and controls the electromagnetic switching valve to guide the hydraulic oil to the boosting oil passage when it is determined that the pressure of the hydraulic oil exceeds the threshold value. This is to switch from the state of squeezing to the state of guiding the hydraulic oil to the decompression oil passage.

The second invention is the pressure booster for aerial work platforms according to the first invention.
The mode selection unit refers to a portion where the operating speed of the hydraulic tool can be selected by a manual operation of an operator.

The third invention is the pressure booster for aerial work platforms according to the first invention.
With hydraulic oil pump,
A plurality of drive sources capable of operating the hydraulic oil pump, and
The mode selection unit refers to a portion where the drive source for operating the hydraulic oil pump can be selected by a manual operation of an operator.

The fourth invention is the pressure booster for aerial work platforms according to the first invention.
With hydraulic oil pump,
A drive source for operating the hydraulic oil pump, and
The mode selection unit refers to a portion where the rotation speed of the drive source can be selected by a manual operation of an operator.

The fifth invention is the pressure booster for aerial work platforms according to the first invention.
With hydraulic oil pump,
The engine that operates the hydraulic oil pump is provided.
The mode selection unit refers to a portion where the rotation speed of the engine can be selected by an automatic operation according to the volume of the engine.

The sixth invention is the pressure booster for aerial work platforms according to the first invention.
With hydraulic oil pump,
The motor that drives the hydraulic oil pump and
A battery that supplies electric power to the motor is provided.
The mode selection unit refers to a portion where the rotation speed of the motor can be selected by automatic operation according to the remaining amount of the battery.

The seventh invention is the pressure booster for aerial work platforms according to the first invention.
With hydraulic oil pump,
An engine that can operate the hydraulic oil pump and
Similarly, a motor that can operate the hydraulic oil pump and
A battery that supplies electric power to the motor is provided.
The mode selection unit refers to a portion where either the engine or the motor, which operates the hydraulic oil pump by automatic operation according to the remaining amount of the battery, can be selected.

The eighth invention is the pressure booster for aerial work platforms according to the first invention.
The mode selection unit refers to a portion where it is possible to select whether or not it is in the cold zone state by automatic operation according to the temperature of the hydraulic oil.

In the pressure booster for aerial work platforms according to the first invention, the controller sets a threshold value according to the selection status of the mode selection unit manually operated by the operator , and determines that the pressure of the hydraulic oil exceeds the threshold value. Sometimes, the electromagnetic switching valve is controlled to switch from the state of guiding the hydraulic oil to the boosting oil passage to the state of guiding the hydraulic oil to the decompression oil passage. According to the pressure booster for aerial work platforms, one mode can be selected from a plurality of modes, and the maximum pressure of the hydraulic oil sent to the flood control tool is increased even if the amount of hydraulic oil delivered by the hydraulic oil pump changes. Can be kept constant.

In the pressure booster for aerial work platforms according to the second invention, the mode selection unit refers to a portion where the operating speed of the hydraulic tool can be selected by manual operation by the operator. According to such a pressure booster for aerial work platforms, one mode can be selected from a plurality of modes regarding the operating speed of the hydraulic tool, and even if the amount of hydraulic oil delivered by the hydraulic oil pump changes, the hydraulic tool is fed to the hydraulic tool. The maximum pressure of the hydraulic fluid to be produced can be kept constant.

In the pressure booster for aerial work platforms according to the third invention, the mode selection unit refers to a portion where one drive source for operating the hydraulic oil pump can be selected by manual operation by the operator. According to the pressure booster for aerial work platforms, one mode can be selected from a plurality of modes for the drive source for operating the hydraulic oil pump, and the hydraulic tool is used even if the amount of hydraulic oil delivered by the hydraulic oil pump changes. The maximum pressure of hydraulic oil sent to can be kept constant.

In the pressure booster for aerial work platforms according to the fourth invention, the mode selection unit refers to a portion where the rotation speed of the drive source can be selected by manual operation by the operator. According to such a pressure booster for aerial work platforms, one mode can be selected from a plurality of modes regarding the rotation speed of the drive source, and even if the amount of hydraulic oil delivered by the hydraulic oil pump changes, it is sent to the hydraulic tool. The maximum pressure of the hydraulic fluid to be produced can be kept constant.

In the pressure booster for aerial work platforms according to the fifth invention, the mode selection unit refers to a portion where the rotation speed of the engine can be selected by automatic operation according to the volume of the engine. According to the pressure booster for aerial work platforms, one mode can be selected from a plurality of modes regarding the volume of the engine, and the operation is sent to the hydraulic tool even if the amount of hydraulic oil delivered by the hydraulic oil pump changes. The maximum pressure of oil can be kept constant.

In the pressure booster for aerial work platforms according to the sixth invention, the mode selection unit refers to a portion where the rotation speed of the motor can be selected by automatic operation according to the remaining battery level. According to the pressure booster for aerial work platforms, one mode can be selected from a plurality of modes with respect to the remaining battery level (power consumption), and even if the amount of hydraulic oil delivered by the hydraulic oil pump changes, the hydraulic pressure is increased. The maximum pressure of hydraulic oil sent to the tool can be kept constant.

In the pressure booster for aerial work platforms according to the seventh invention, the mode selection unit is a portion where either an engine or a motor that operates a hydraulic oil pump by automatic operation according to the remaining battery level can be selected. Point to. According to the pressure booster for the high-altitude work vehicle, one mode can be selected from a plurality of modes for the engine or the motor that operates the hydraulic oil pump, and the amount of hydraulic oil delivered by the hydraulic oil pump changes. However, the maximum pressure of the hydraulic oil sent to the hydraulic tool can be kept constant.

In the pressure booster for aerial work platforms according to the eighth invention, the mode selection unit refers to a portion capable of selecting whether or not it is in a cold zone state by automatic operation according to the temperature of the hydraulic oil. According to the pressure booster for aerial work platforms, one mode can be selected from a plurality of modes with respect to the temperature of the hydraulic oil, and even if the viscosity of the hydraulic oil changes significantly, the hydraulic oil sent to the hydraulic tool The maximum pressure can be kept constant.

The figure which shows the aerial work platform. The figure which shows the structure of the pressure booster. The figure which shows the flow direction of hydraulic oil at the time of a temporary holding operation. The figure which shows the flow direction of hydraulic oil at the pressurization stage at the time of this compression operation. The figure which shows the flow direction of hydraulic oil at the main pressure stage at the time of this compression operation. The figure which shows the flow direction of hydraulic oil at the time of a return operation. The figure which shows the operation mode of the hydraulic crimping tool. The figure which shows the control system of a pressure booster. The figure which shows the control mode of a pressure booster. The figure which shows the control mode of a pressure booster. The figure which shows the control mode of a pressure booster. The figure which shows the control mode of a pressure booster. The figure which shows the control mode of a pressure booster. The figure which shows the control mode of a pressure booster. The figure which shows the control mode of a pressure booster.

First, the aerial work platform 1 will be described with reference to FIG.

The aerial work platform 1 is used for wiring work in which the sleeve is crimped to connect the power lines. The aerial work platform 1 has the aerial work platform 6 in the vehicle 2.

The vehicle 2 conveys the aerial work platform 6. The vehicle 2 is provided with a driver's cab, a plurality of wheels 3, and is further equipped with an engine 4. The vehicle 2 travels by transmitting the driving force of the engine 4 to the wheels 3. Further, the vehicle 2 includes an outrigger 5. The outrigger 5 is composed of a beam that can be expanded and contracted in the left-right direction of the vehicle 2 and a jack cylinder that can be expanded and contracted in the vertical direction of the vehicle 2. The vehicle 2 can expand the working range of the aerial work platform 6 by operating the outriggers 5.

The aerial work platform 6 enables an operator to work at a high place. The aerial work platform 6 includes a swivel base 7, a telescopic boom 8, a bucket 9, an undulating cylinder 10, and an operating device 11.

The swivel base 7 swivels the telescopic boom 8. The swivel base 7 is arranged on the upper part of the frame via an annular bearing. The swivel base 7 is configured to swivel around the center of the annular bearing as the swivel center. The swivel base 7 is swiveled by a hydraulic actuator (not shown).

The telescopic boom 8 moves the bucket 9 up and down. The telescopic boom 8 has a structure in which each of the constituent members has a square tubular shape and is housed in the telescopic boom 8 in order from the largest one. The telescopic boom 8 is stretched and contracted by a telescopic cylinder (not shown). The base end of the telescopic boom 8 is swingably attached to the swivel base 7.

The bucket 9 secures a working space for the worker. The bucket 9 is configured to surround the boarded worker. One end of the bucket 9 is swingably attached to the telescopic boom 8. The bucket 9 is swung in the elevation and horizontal directions by a hydraulic actuator (not shown).

The undulating cylinder 10 erects or lays down the telescopic boom 8. The base end portion of the undulating cylinder 10 is swingably connected to the swivel base 7, and the tip end portion thereof is swingably connected to the telescopic boom 8. The undulating cylinder 10 erects the telescopic boom 8 by extending itself. Further, the undulating cylinder 10 causes the telescopic boom 8 to lie down by contracting itself.

The operating device 11 operates the swivel base 7, the telescopic boom 8, the bucket 9, and the like. The operating device 11 is provided at the rear of the vehicle 2 and inside the bucket 9. The operation device 11 has various mode selection units 41, 42, 43, 44, 45, 46, 47, in addition to an operation tool for instructing the rotation, expansion, contraction, undulation, and the like of the expansion / contraction boom 8. The mode selection units 41, 42, 43, 44, 45, 46, 47 will be described later.

The pressure booster 12 will be described below with reference to FIG.

The pressure boosting device 12 includes a pressure boosting cylinder 13, a pressure sensor 14, a preload electromagnetic switching valve (hereinafter referred to as "preload switching valve") 17, a relief valve 21, and a main pressure electromagnetic switching valve (hereinafter referred to as "preload switching valve"). It is composed of 24 (referred to as a "main pressure switching valve"), a pilot type check valve 27, and a hydraulic oil pump 28. The preload switching valve 17 and the main pressure switching valve 24 are controlled by the controller 31 (see FIG. 8).

The pressure boosting cylinder 13 boosts the hydraulic oil. The pressure boosting cylinder 13 has a structure in which a large-diameter cylinder and a small-diameter cylinder are connected to each other, and a large-diameter piston 13d is slidably housed inside the large-diameter cylinder. Therefore, the forward side oil chamber (hereinafter referred to as "head side oil chamber") 13c is configured on the head side of the large diameter piston 13d, and the return side oil chamber (hereinafter referred to as "rod side") is formed on the rod side of the large diameter piston 13d. The oil chamber) 13b is configured. Further, a small diameter piston 13e is slidably housed inside the small diameter cylinder. Therefore, the pressure boosting chamber 13a is configured in one of the small diameter pistons 13e. The large-diameter piston 13d and the small-diameter piston 13e are connected via a rod 13f. Therefore, in the pressure boosting cylinder 13, when the hydraulic oil is supplied to the head side oil chamber 13c, the force applied to the large diameter piston 13d is transmitted to the small diameter piston 13e. As a result, the pressure boosting cylinder 13 pushes out the hydraulic oil in the pressure boosting chamber 13a by the force calculated by the area ratio of the large diameter piston 13d and the small diameter piston 13e, and eventually the hydraulic tool (“hydraulic crimping tool 100” in the present application”. The pressure of the hydraulic oil sent to) is increased.

The pressure sensor 14 detects the pressure of the hydraulic oil sent to the hydraulic crimping tool 100. In the pressure boosting device 12, the pressure sensor 14 is attached to the pressure boosting chamber 13a of the pressure boosting cylinder 13. However, it may be installed at an appropriate position in the filling oil passage 15 that guides the hydraulic oil to the pressure boosting chamber 13a. A hydraulic hose is connected to the filling oil passage 15 in the middle portion thereof. A joint 16 to which the hydraulic crimping tool 100 can be connected is attached to the end of the hydraulic hose. Therefore, the hydraulic oil with increased pressure can be supplied to the hydraulic crimping tool 100 connected to the joint 16.

The preload switching valve 17 guides hydraulic oil to the low pressure oil passage 18 or the preload oil passage 19. In the preload switching valve 17, one of one port and the other port is communicated with the supply port by sliding a spool (not shown). One port of the preload switching valve 17 is connected to the filling oil passage 15 via the low pressure oil passage 18. Further, the other port of the preload switching valve 17 is connected to the filling oil passage 15 via the preload oil passage 19. A hydraulic oil pump 28 is connected to the supply port of the preload switching valve 17 via a discharge oil passage 20. Therefore, the hydraulic oil is supplied to the low pressure oil passage 18 and the preload oil passage 19 at the discharge pressure of the hydraulic oil pump 28 (hereinafter referred to as “preload”).

The relief valve 21 limits the pressure of the hydraulic oil to a set value or less. The relief valve 21 is connected to the terminal portion of the low pressure oil passage 18. More specifically, the relief valve 21 is connected to one end portion branched from the low pressure oil passage 18. The relief valve 21 is connected to the hydraulic oil tank 30 via a drainage oil passage. Therefore, when the pressure of the hydraulic fluid flowing through the low pressure oil passage 18 exceeds the set value, - relief valve 21 is to be discharged a part of the hydraulic fluid in the low-pressure oil passage 18 to the hydraulic oil tank 30. Therefore, the pressure of the hydraulic oil flowing through the low pressure oil passage 18 is limited to a pressure lower than the preload (hereinafter referred to as "low pressure"). The low-pressure oil passage 18 is provided with a throttle 22 on the upstream side of the branch point. Further, a check valve 23 is arranged in the other halfway portion branched from the low-pressure oil passage 18 and the halfway portion of the preload oil passage 19.

Here, assuming that the electromagnet of the preload switching valve 17 is not excited (when the operation signal is not received from the controller 31), the low pressure oil passage 18 and the preload oil passage 19 are connected to the hydraulic oil tank 30. The spool is moved to the II position where it is in the state. That is, the preload switching valve 17 is switched to a state in which the hydraulic oil delivered by the hydraulic oil pump 28 is not supplied to the filling oil passage 15.

Further, assuming that the electromagnet is excited so that one port of the preload switching valve 17 and the supply port communicate with each other (when an operation signal for supplying low-pressure hydraulic oil is received from the controller 31), the low voltage is assumed. The spool is moved to the I position where the oil passage 18 and the discharge oil passage 20 are communicated with each other and the preload oil passage 19 is connected to the hydraulic oil tank 30. That is, the preload switching valve 17 is switched to a state in which hydraulic oil is supplied to the filling oil passage 15 through the low pressure oil passage 18. At this time, low-pressure hydraulic oil is supplied to the pressure boosting chamber 13a of the pressure boosting cylinder 13 through the filling oil passage 15.

Further, assuming that the electromagnet is excited so that the other port of the preload switching valve 17 and the supply port communicate with each other (when an operation signal for supplying the preload hydraulic oil is received from the controller 31), the preload is assumed. The spool is moved to position III in which the oil passage 19 and the discharge oil passage 20 are communicated with each other and the low pressure oil passage 18 is connected to the hydraulic oil tank 30. That is, the preload switching valve 17 is switched to a state in which hydraulic oil is supplied to the filling oil passage 15 through the preload oil passage 19. At this time, preload hydraulic oil is supplied to the pressure boosting chamber 13a of the pressure boosting cylinder 13 through the filling oil passage 15.

The main pressure switching valve 24 guides the hydraulic oil to the pressure increasing oil passage 26 or the depressurizing oil passage 25. In the main pressure switching valve 24, one of one port and the other port is communicated with the supply port by sliding a spool (not shown). One port of the main pressure switching valve 24 is connected to the head side oil chamber 13c of the pressure boosting cylinder 13 via the pressure boosting oil passage 26. Further, the other port of the main pressure switching valve 24 is connected to the rod side oil chamber 13b of the pressure boosting cylinder 13 via the pressure reducing oil passage 25. A hydraulic oil pump 28 is connected to the supply port of the main pressure switching valve 24 via a discharge oil passage 20. Therefore, the hydraulic oil is supplied to the pressure increasing oil passage 26 and the depressurizing oil passage 25 at the discharge pressure of the hydraulic oil pump 28 (hereinafter referred to as “preload”).

Here, assuming that the electromagnet of the main pressure switching valve 24 is not excited (when the operation signal is not received from the controller 31), the pressure boosting oil passage 26 and the pressure reducing oil passage 25 are connected to the hydraulic oil tank 30. The spool is moved to the II position where it is in a closed state. That is, the main pressure switching valve 24 is switched to a state in which the hydraulic oil delivered by the hydraulic oil pump 28 is not supplied to either the head side oil chamber 13c or the rod side oil chamber 13b of the pressure boosting cylinder 13.

Further, assuming that the electromagnet is excited so that one port of the main pressure switching valve 24 and the supply port communicate with each other (when an operation signal for increasing the hydraulic pressure of the hydraulic oil is received from the controller 31), the increase is assumed. The spool is moved to the position III in which the pressure oil passage 26 and the discharge oil passage 20 are communicated with each other and the pressure reducing oil passage 25 is connected to the hydraulic oil tank 30. That is, the main pressure switching valve 24 is switched to a state in which hydraulic oil is supplied to the head side oil chamber 13c of the pressure boosting cylinder 13 through the pressure boosting oil passage 26. At this time, in the pressure boosting cylinder 13, the small diameter piston 13e slides to one side together with the large diameter piston 13d to reduce the volume of the pressure boosting chamber 13a, so that the hydraulic oil is pushed out from the pressure boosting chamber 13a.

Further, assuming that the electromagnet is excited so that the other port of the main pressure switching valve 24 and the supply port communicate with each other (when an operation signal for reducing the hydraulic pressure of the hydraulic oil is received from the controller 31), the pressure is reduced. The spool is moved to the I position where the oil passage 25 and the discharge oil passage 20 are connected to each other and the pressure boosting oil passage 26 is connected to the hydraulic oil tank 30. That is, the main pressure switching valve 24 is switched to a state in which hydraulic oil is supplied to the rod side oil chamber 13b of the pressure increasing cylinder 13 through the pressure reducing oil passage 25. At this time, in the pressure boosting cylinder 13, the small diameter piston 13e slides to the other side together with the large diameter piston 13d to expand the volume of the pressure boosting chamber 13a, so that the hydraulic oil is drawn into the pressure boosting chamber 13a.

The pilot check valve 27 opens the filling oil passage 15. The pilot check valve 27 is connected to the terminal portion of the filling oil passage 15. The pilot check valve 27 is connected to the hydraulic oil tank 30 via a drainage oil passage. Further, in the pilot type check valve 27, the pilot hydraulic oil is supplied from the pressure reducing oil passage 25. Therefore, when the main pressure switching valve 24 is switched to a state of supplying hydraulic oil to the rod side oil chamber 13b of the pressure boosting cylinder 13, the pilot type check valve 27 uses a part of the hydraulic oil in the filling oil passage 15. It can be discharged to the hydraulic oil tank 30. Therefore, the hydraulic oil in the filling oil passage 15 is quickly discharged without being sent to the hydraulic crimping tool 100.

In addition, the hydraulic oil delivered by the hydraulic oil pump 28 is supplied to the preload switching valve 17 and the main pressure switching valve 24 through the discharge oil passage 20, respectively. A relief valve 29 for a hydraulic oil pump is arranged in the discharge oil passage 20. The relief valve 29 for the hydraulic oil pump limits the pressure of the hydraulic oil delivered by the hydraulic oil pump 28 to a set value or less. In the aerial work platform 1, the hydraulic oil pump 28 is driven by the engine 4 or the motor 32.

Next, the operation mode of the hydraulic crimping tool 100 and the flow direction of the hydraulic oil in the pressure booster 12 will be described with reference to FIGS. 2 to 7.

The hydraulic crimping tool 100 grips and crimps the sleeve S. In the hydraulic crimping tool 100, the movable portion 100a moves toward the receiving portion 100b by the hydraulic oil sent from the pressure boosting device 12. As shown in FIG. 7, the hydraulic crimping tool 100 has a stop operation s0 in which the movable portion 100a is stopped, and a temporary holding operation s1 in which the movable portion 100a moves toward the receiving portion 100b to grip the sleeve S. Preloading step s2 of the main compression operation in which the movable portion 100a moves with a predetermined force to apply a pressurized load to the sleeve S, and the main compression in which the movable portion 100a moves with a predetermined force to apply a main pressure load to the sleeve S. The main pressure step s3 of the operation and the return operation s4 in which the movable portion 100a moves away from the receiving portion 100b to release the sleeve S are performed.

As shown in FIG. 2, when the hydraulic crimping tool 100 performs the stop operation s0, the controller 31 connects the spool position of the preload switching valve 17 to the hydraulic oil tank 30 by the low pressure oil passage 18 and the preload oil passage 19. Move to the II position where the oil pressure is reached. At the same time, the controller 31 moves the spool position of the main pressure switching valve 24 to the position II in which the pressure increasing oil passage 26 and the pressure reducing oil passage 25 are connected to the hydraulic oil tank 30. As a result, the hydraulic crimping tool 100 stops with the movable portion 100a separated from the receiving portion 100b.

As shown in FIG. 3, when the hydraulic crimping tool 100 performs the temporary holding operation s1, the controller 31 connects the spool position of the preload switching valve 17 to the low pressure oil passage 18 to the discharge oil passage 20, and preload oil. The road 19 is moved to the I position where it is connected to the hydraulic oil tank 30. However, the controller 31 maintains the spool position of the main pressure switching valve 24 at the position II in which the pressure increasing oil passage 26 and the pressure reducing oil passage 25 are connected to the hydraulic oil tank 30. As a result, the hydraulic crimping tool 100 can grip the sleeve S because the movable portion 100a moves toward the receiving portion 100b by the low-pressure hydraulic oil.

As shown in FIG. 4, when the hydraulic crimping tool 100 performs the preload step s2 of the main compression operation, the controller 31 connects the spool position of the preload switching valve 17 to the preload oil passage 19 to the discharge oil passage 20. , The low pressure oil passage 18 is moved to the position III in which the hydraulic oil tank 30 is connected. However, the controller 31 maintains the spool position of the main pressure switching valve 24 at the position II in which the pressure increasing oil passage 26 and the pressure reducing oil passage 25 are connected to the hydraulic oil tank 30. As a result, in the hydraulic crimping tool 100, the movable portion 100a moves toward the receiving portion 100b due to the hydraulic oil of the preload, so that the preload can be applied to the sleeve S.

As shown in FIG. 5, when the hydraulic crimping tool 100 performs the main pressure step s3 of the main compression operation, the controller 31 operates the low pressure oil passage 18 and the preload oil passage 19 at the spool position of the preload switching valve 17. Move it to the II position where it is connected to the oil tank 30. At the same time, the controller 31 moves the spool position of the main pressure switching valve 24 to the position III in which the pressure increasing oil passage 26 is connected to the discharge oil passage 20 and the pressure reducing oil passage 25 is connected to the hydraulic oil tank 30. .. As a result, in the hydraulic crimping tool 100, the movable portion 100a moves toward the receiving portion 100b due to the increased pressure of the hydraulic oil, so that the main pressure load can be applied to the sleeve S. At this time, the sleeve S can be crimped.

As shown in FIG. 6, when the hydraulic crimping tool 100 performs the return operation s4, the controller 31 connects the spool position of the preload switching valve 17 to the hydraulic oil tank 30 by the low pressure oil passage 18 and the preload oil passage 19. It is maintained in the II position where it is in the same state. However, the controller 31 moves the spool position of the main pressure switching valve 24 to the I position where the pressure reducing oil passage 25 is connected to the discharge oil passage 20 and the pressure increasing oil passage 26 is connected to the hydraulic oil tank 30. .. As a result, in the hydraulic crimping tool 100, the movable portion 100a is moved away from the receiving portion 100b by the spring, so that the sleeve S can be opened.

Next, the control system of the pressure booster 12 and the control mode of the pressure booster 12 will be described with reference to FIGS. 8 to 14.

The control system of the pressure booster 12 is composed of various mode selection units 41, 42, 43, 44, 45, 46, 47, etc., in addition to the controller 31.

The controller 31 mainly controls the preload switching valve 17 and the main pressure switching valve 24 that constitute the pressure boosting device 12. Further, the controller 31 can also control the engine clutch 4C and the motor clutch 32C that transmit these driving forces in addition to the rotational speeds of the engine 4 and the motor 32. Further, the controller 31 can also acquire the pressure signal from the pressure sensor 14. The controller 31 may be configured such that a CPU, ROM, RAM, HDD and the like are connected by a bus, or may be configured by a one-chip LSI or the like.

The mode selection unit 41 refers to a portion of the control system of the pressure booster 12 in which the operating speed of the hydraulic crimping tool 100 can be selected by manual operation by an operator. The mode selection unit 41 has a configuration including a changeover switch 41S, and can freely select either "high-speed mode" or "low-speed mode". The changeover switch 41S is arranged at least in the operation device 11 provided inside the bucket 9 so that the operator can operate the switch 41S while performing the caulking work.

First, it is assumed that the operator selects the "high-speed mode" while the hydraulic oil pump 28 is being driven by the engine 4. Upon recognizing the selection of the "high-speed mode", the controller 31 gives an instruction to change the rotation speed of the engine 4. Specifically, an instruction is given to increase the rotation speed of the engine 4. This is because by increasing the amount of hydraulic oil delivered by the hydraulic oil pump 28, the pressure of the hydraulic oil sent to the hydraulic crimping tool 100 rises faster, and by extension, the operating speed of the hydraulic crimping tool 100 is increased. .. Further, in the pressure booster 12, the threshold value Pa is set low so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not increase, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pa. When this happens, the return operation is switched to s4 (see the pressure transition La in FIG. 9). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

Next, it is assumed that the operator selects the "low speed mode" while the hydraulic oil pump 28 is being driven by the engine 4. Upon recognizing the selection of the "low speed mode", the controller 31 gives an instruction to change the rotation speed of the engine 4. Specifically, an instruction is given to reduce the rotation speed of the engine 4. This is because by reducing the amount of hydraulic oil delivered by the hydraulic oil pump 28, the pressure rise of the hydraulic oil sent to the hydraulic crimping tool 100 is slowed down, which in turn slows down the operating speed of the hydraulic crimping tool 100. .. Further, in the pressure booster 12, the threshold value Pb is set high so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not decrease, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pb. When this happens, the return operation is switched to s4 (see the pressure transition Lb in FIG. 9). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

According to such a pressure booster 12, one mode can be selected from a plurality of modes (“high speed mode” and “low speed mode”) with respect to the operating speed of the hydraulic crimping tool 100, and the hydraulic oil pump 28 sends out. Even if the amount of hydraulic oil changes, the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 can be kept constant.

In addition, the mode selection unit 41 can freely select from two modes, "high-speed mode" and "low-speed mode", but the mode selection unit 41 is not limited to this mode and may have other modes. Although it is assumed here that the hydraulic oil pump 28 is driven by the engine 4, the same control mode is used even when the hydraulic oil pump 28 is driven by the motor 32.

The mode selection unit 42 refers to a portion of the control system of the pressure booster 12 that can select one drive source for moving the hydraulic oil pump 28 by manual operation by an operator. The mode selection unit 42 has a configuration including a changeover switch 42S, and can freely select either an “engine drive mode” or a “motor drive mode”. The changeover switch 42S is arranged at least in the operation device 11 provided inside the bucket 9 so that the operator can operate the switch 42S while performing the caulking work.

First, it is assumed that the operator selects the "engine drive mode" while the hydraulic oil pump 28 is being driven by the motor 32. Upon recognizing the selection of the "engine drive mode", the controller 31 gives an instruction to change the operating states of the motor clutch 32C and the engine clutch 4C. Specifically, the drive shaft and the driven shaft of the motor clutch 32C are separated from each other, and an instruction is given to connect the drive shaft and the driven shaft of the engine clutch 4C. When the hydraulic oil pump 28 is driven by the engine 4, the amount of hydraulic oil delivered by the hydraulic oil pump 28 unintentionally increases due to the difference in rotational speed. Therefore, in the pressure booster 12, the threshold value Pc is set low so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not increase, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pc. When this happens, the return operation is switched to s4 (see the pressure transition Lc in FIG. 10). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

Next, it is assumed that the operator selects the "motor drive mode" while the hydraulic oil pump 28 is being driven by the engine 4. Upon recognizing the selection of the "motor drive mode", the controller 31 gives an instruction to change the operating states of the engine clutch 4C and the motor clutch 32C. Specifically, the drive shaft and the driven shaft of the engine clutch 4C are separated from each other, and the drive shaft and the driven shaft of the motor clutch 32C are instructed to be connected. When the hydraulic oil pump 28 is driven by the motor 32, the amount of hydraulic oil delivered by the hydraulic oil pump 28 is unintentionally reduced due to the difference in rotational speed. Therefore, in the pressure booster 12, the threshold value Pd is set higher so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not decrease, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pd. When this happens, the return operation is switched to s4 (see the pressure transition Ld in FIG. 10). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

According to such a pressure boosting device 12, one mode can be selected from a plurality of modes (“engine drive mode” and “motor drive mode”) with respect to the drive source for moving the hydraulic oil pump 28, and the hydraulic oil pump 28 Even if the amount of hydraulic oil sent out by the engine changes, the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 can be kept constant.

In addition, the mode selection unit 42 can freely select from two modes, an "engine drive mode" and a "motor drive mode", but the mode selection unit 42 is not limited to this mode and may have other modes. Although the configuration provided with the "motor drive mode" is assumed here, the same control mode can be obtained even with a configuration equipped with a small engine instead of the motor 32.

The mode selection unit 43 refers to a portion of the control system of the pressure booster 12 in which the rotation speed of the drive source can be selected by manual operation by an operator. The mode selection unit 43 has a configuration including a changeover switch 43S, and can freely select either "high-speed mode" or "low-speed mode". The changeover switch 43S is arranged at least in the operation device 11 provided inside the bucket 9 so that the operator can operate the changeover switch 43S while performing the caulking work.

First, it is assumed that the operator selects the "high-speed mode" while the hydraulic oil pump 28 is being driven by the engine 4. Upon recognizing the selection of the "high-speed mode", the controller 31 gives an instruction to change the rotation speed of the engine 4. Specifically, an instruction is given to increase the rotation speed of the engine 4. Further, in the pressure booster 12, the threshold value Pe is set low so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not increase, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pe. When this is done, the return operation is switched to s4 (see the pressure transition Le in FIG. 11). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

Next, it is assumed that the operator selects the "low speed mode" while the hydraulic oil pump 28 is being driven by the engine 4. Upon recognizing the selection of the "low speed mode", the controller 31 gives an instruction to change the rotation speed of the engine 4. Specifically, an instruction is given to reduce the rotation speed of the engine 4. Further, in the pressure booster 12, the threshold value Pf is set high so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not decrease, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pf. When this happens, the return operation is switched to s4 (see the pressure transition Lf in FIG. 11). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

According to such a pressure booster 12, one mode can be selected from a plurality of modes (“high speed mode” and “low speed mode”) with respect to the rotation speed of the drive source, and the amount of hydraulic oil delivered by the hydraulic oil pump 28. The maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 can be kept constant even if the pressure changes.

In addition, the mode selection unit 43 can freely select from two modes, "high-speed mode" and "low-speed mode", but the mode selection unit 43 is not limited to this mode and may have other modes. Although it is assumed here that the hydraulic oil pump 28 is driven by the engine 4, the same control mode is used even when the hydraulic oil pump 28 is driven by the motor 32. In addition, this control mode can be applied even to a structure in which an operation position such as an accelerator lever (not shown) can be selected.

The mode selection unit 44 refers to a portion of the control system of the pressure boosting device 12 in which the rotation speed of the engine 4 can be selected by automatic operation according to the volume of the engine 4. The mode selection unit 44 has a configuration including a volume sensor 44S, and can freely select either "normal mode" or "bass mode". The volume sensor 44S is arranged at least at a position that does not block the sound of the vehicle 2 so that the volume of the engine 4 can be measured.

First, it is assumed that the controller 31 selects the "normal mode" while the hydraulic oil pump 28 is being driven by the engine 4. Upon recognizing the selection of the "normal mode", the controller 31 gives an instruction to change the rotation speed of the engine 4. Specifically, an instruction is given to increase the rotation speed of the engine 4. Further, in the pressure booster 12, the threshold Pg is set low so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not increase, and it is determined that the pressure of the hydraulic oil exceeds the threshold Pg. When this happens, the return operation is switched to s4 (see the pressure transition Lg in FIG. 12). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

Next, it is assumed that the controller 31 selects the "bass mode" while the hydraulic oil pump 28 is being driven by the engine 4. When the controller 31 recognizes the selection of the "bass mode", it gives an instruction to change the rotation speed of the engine 4. Specifically, an instruction is given to reduce the rotation speed of the engine 4. Further, in the pressure booster 12, the threshold value Ph is set high so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not decrease, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Ph. When this happens, the return operation is switched to s4 (see the pressure transition Lh in FIG. 12). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

According to such a pressure booster 12, one mode can be selected from a plurality of modes (“normal mode” and “bass mode”) with respect to the volume of the engine 4, and the amount of hydraulic oil delivered by the hydraulic oil pump 28 is Even if it changes, the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 can be kept constant.

In addition, the mode selection unit 44 can freely select from two modes, "normal mode" and "bass mode", but it is not necessary to limit this, and other modes may be available. Here, a control mode in which the controller 31 selects the "normal mode" by automatic operation is also assumed, but the "normal mode" is not selected by automatic operation, only the "bass mode" is selected. May be good. This is appropriate considering that it is a technique for reducing the rotation speed of the engine 4 to reduce the volume.

The mode selection unit 45 refers to a portion of the control system of the pressure booster 12 in which the rotation speed of the motor 32 can be selected by automatic operation according to the remaining amount of the battery 32B. The mode selection unit 45 has a configuration including a voltage sensor 45S, and can freely select either a "normal mode" or a "energy saving mode". The voltage sensor 45S is arranged at least in the vicinity of the battery 32B mounted on the vehicle 2 so that the remaining amount of the battery 32B can be measured.

First, it is assumed that the controller 31 selects the "normal mode" while the hydraulic oil pump 28 is being driven by the motor 32. Upon recognizing the selection of the "normal mode", the controller 31 gives an instruction to change the rotation speed of the motor 32. Specifically, an instruction is given to increase the rotation speed of the motor 32. Further, in the pressure booster 12, the threshold value Pi is set low so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not increase, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pi. When this happens, the return operation is switched to s4 (see the pressure transition Li in FIG. 13). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

Next, it is assumed that the controller 31 selects the "energy saving mode" while the hydraulic oil pump 28 is being driven by the motor 32. When the controller 31 recognizes the selection of the "energy saving mode", it gives an instruction to change the rotation speed of the motor 32. Specifically, an instruction is given to reduce the rotation speed of the motor 32. Further, in the pressure booster 12, the threshold value Pj is set higher so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not decrease, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pj. When this happens, the return operation is switched to s4 (see the pressure transition Lj in FIG. 13). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

According to such a pressure booster 12, one mode can be selected from a plurality of modes (“normal mode” and “energy saving mode”) with respect to the remaining amount (power consumption) of the battery 32B, and the hydraulic oil pump 28 Even if the amount of hydraulic oil to be sent out changes, the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 can be kept constant.

In addition, the mode selection unit 45 can freely select from two modes, "normal mode" and "energy saving mode", but the mode selection unit 45 is not limited to this mode and may have other modes. Here, a control mode in which the controller 31 selects the "normal mode" by automatic operation is also assumed, but the "normal mode" is not selected by automatic operation, only the "energy saving mode" is selected. May be good. This is appropriate considering that it is a technique for reducing the rotation speed of the motor 32 to reduce power consumption.

The mode selection unit 46 refers to a portion of the control system of the pressure booster 12 that can select either the engine 4 or the motor 32 that operates the hydraulic oil pump 28 by automatic operation according to the remaining amount of the battery 32B. The mode selection unit 46 has a configuration including a voltage sensor 46S, and can freely select either an “engine drive mode” or a “motor drive mode”. The voltage sensor 46S is arranged at least in the vicinity of the battery 32B mounted on the vehicle 2 so that the remaining amount of the battery 32B can be measured.

First, it is assumed that the controller 31 selects the "engine drive mode" while the hydraulic oil pump 28 is being driven by the motor 32. Upon recognizing the selection of the "engine drive mode", the controller 31 gives an instruction to change the operating states of the motor clutch 32C and the engine clutch 4C. Specifically, the drive shaft and the driven shaft of the motor clutch 32C are separated from each other, and an instruction is given to connect the drive shaft and the driven shaft of the engine clutch 4C. When the hydraulic oil pump 28 is driven by the engine 4, the amount of hydraulic oil delivered by the hydraulic oil pump 28 unintentionally increases due to the difference in rotational speed. Therefore, in the pressure booster 12, the threshold value Pk is set low so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not increase, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pk. When this happens, the return operation is switched to s4 (see the pressure transition Lk in FIG. 14). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

Next, it is assumed that the controller 31 selects the "motor drive mode" while the hydraulic oil pump 28 is being driven by the engine 4. Upon recognizing the selection of the "motor drive mode", the controller 31 gives an instruction to change the operating states of the engine clutch 4C and the motor clutch 32C. Specifically, the drive shaft and the driven shaft of the engine clutch 4C are separated from each other, and the drive shaft and the driven shaft of the motor clutch 32C are instructed to be connected. When the hydraulic oil pump 28 is driven by the motor 32, the amount of hydraulic oil delivered by the hydraulic oil pump 28 is unintentionally reduced due to the difference in rotational speed. Therefore, in the pressure booster 12, the threshold value Pl is set high so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not decrease, and it is determined that the pressure of the hydraulic oil exceeds the threshold value Pl. When this happens, the return operation is switched to s4 (see the pressure transition Ll in FIG. 14). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

According to such a pressure boosting device 12, one mode can be selected from a plurality of modes (“engine drive mode” and “motor drive mode”) with respect to the engine 4 or the motor 32 that drives the hydraulic oil pump 28. Moreover, even if the amount of hydraulic oil delivered by the hydraulic oil pump 28 changes, the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 can be kept constant.

In addition, the mode selection unit 46 is freely selectable from two modes, an "engine drive mode" and a "motor drive mode", but the mode selection unit 46 is not limited to this mode and may have other modes. Here, a control mode in which the controller 31 selects the "motor drive mode" by automatic operation is also assumed, but the "motor drive mode" is not selected by automatic operation, only the "engine drive mode" is selected. It may be. This is appropriate considering that it is a technique for reducing power consumption by switching from the motor 32 to the engine 4. Further, the mode selection unit 46 may switch in the order of "normal mode" → "energy saving mode" → "engine drive mode" by automatic operation according to the remaining amount of the battery 32B by cooperating with the mode selection unit 45. It is possible.

The mode selection unit 47 refers to a portion of the control system of the pressure booster 12 that can select whether or not it is in the cold zone state by automatic operation according to the temperature of the hydraulic oil. The mode selection unit 47 includes a temperature sensor 47S, and can freely select either a "warm zone mode" or a "cold zone mode". The temperature sensor 47S is arranged at least in the vicinity of the hydraulic oil tank mounted on the vehicle 2 so that the temperature of the hydraulic oil can be measured.

First, assume a case where the controller 31 selects the "warm zone mode". When the temperature of the hydraulic oil is high, the amount of hydraulic oil supplied to the head side oil chamber 13c increases and the amount of hydraulic oil extruded from the pressure boosting chamber 13a also increases due to the low viscosity, so it is sent to the hydraulic crimping tool 100. The maximum pressure Pmax of the hydraulic oil to be produced becomes higher than the target value. Therefore, when the controller 31 recognizes the selection of the "warm mode", the threshold value Pm is set low so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not increase, and the pressure of the hydraulic oil is set low. Is switched to the return operation s4 when it is determined that the pressure exceeds the threshold value Pm (see the pressure transition Lm in FIG. 15). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

Next, it is assumed that the controller 31 selects the "cold zone mode". When the temperature of the hydraulic oil is low, the amount of hydraulic oil supplied to the head side oil chamber 13c decreases and the amount of hydraulic oil extruded from the pressure boosting chamber 13a also decreases due to the high viscosity, so it is sent to the hydraulic crimping tool 100. The maximum pressure Pmax of the hydraulic oil to be produced becomes lower than the target value. Therefore, when the controller 31 recognizes the selection of the "cold zone mode", the threshold value Pn is set high so that the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 does not decrease, and the hydraulic oil is used. When it is determined that the pressure exceeds the threshold value Pn, the return operation s4 is switched to (see the pressure transition Ln in FIG. 15). That is, the main pressure switching valve 24 is controlled to switch from the state of guiding the hydraulic oil to the pressure increasing oil passage 26 to the state of guiding the hydraulic oil to the decompression oil passage 25.

According to such a pressure booster 12, one mode can be selected from a plurality of modes (“warm zone mode” and “cold zone mode”) with respect to the temperature of the hydraulic oil, and the viscosity of the hydraulic oil changes significantly. Even so, the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 can be kept constant.

In addition, the mode selection unit 47 can freely select from two modes, "warm mode" and "cold mode", but the mode selection unit 47 is not limited to this, and other modes may be available. Here, a control mode in which the controller 31 automatically selects the "warm zone mode" is assumed, but the "warm zone mode" is not selected by the automatic operation, but the "cold zone mode" is selected. May be only. This is appropriate considering that it is a technique for adjusting the maximum pressure Pmax of the hydraulic oil sent to the hydraulic crimping tool 100 when the temperature of the hydraulic oil is low and the viscosity is high.

The features of the present invention are summarized below.

That is, in the pressure booster 12 for the high-altitude work vehicle 1 according to the present invention, the controller 31 sets a threshold value (Pa, Pb ...) According to the selection status of the mode selection unit (41, 42 ...). When it is determined that the pressure of the hydraulic oil exceeds the threshold value (Pa, Pb ...), The electromagnetic switching valve (24) is controlled to guide the hydraulic oil to the pressure boosting oil passage 26, and then the pressure reducing oil passage 25 Switch to the state of guiding the hydraulic oil to. According to the pressure booster 12 for the aerial work platform 1, one mode can be selected from a plurality of modes, and even if the amount of hydraulic oil delivered by the hydraulic oil pump 28 changes, it is sent to the hydraulic tool (100). The maximum pressure Pmax of the hydraulic oil can be kept constant.

The above-described embodiment only shows a typical embodiment, and is various as long as it does not deviate from the gist of one embodiment, for example, the mode selection unit (41, 42 ...) Is configured to be steplessly adjustable. It can be transformed and implemented.

1 Aerial work platform 12 Pressure booster 13 Pressure booster cylinder 13a Pressure booster chamber 13b Rod side oil chamber (recovery side oil chamber)
13c Head side oil chamber (forward side oil chamber)
14 Pressure sensor 15 Filled oil passage 18 Low pressure oil passage 19 Preload oil passage 24 Main pressure switching valve (electromagnetic switching valve)
25 Decompression oil passage 26 Pressure increase oil passage 31 Controller 41 Mode selection unit 100 Hydraulic crimping tool (hydraulic tool)
Pa threshold Pb threshold

Claims (8)

Booster cylinder and
A filling oil passage that guides hydraulic oil to the boosting chamber of the boosting cylinder, and
A booster oil passage that guides hydraulic oil to the oil chamber on the forward side of the booster cylinder,
A decompression oil passage that guides hydraulic oil to the oil chamber on the return side of the booster cylinder, and
An electromagnetic switching valve for guiding hydraulic oil to the pressure increasing oil passage or the pressure reducing oil passage is provided.
When the electromagnetic switching valve guides the hydraulic oil to the pressure boosting oil passage, the hydraulic oil is pushed out from the pressure boosting chamber and the hydraulic oil sent to the hydraulic tool can be boosted.
In a pressure booster for aerial work platforms, when the electromagnetic switching valve guides the hydraulic oil to the pressure reducing oil passage, the hydraulic oil is drawn into the pressure boosting chamber and the hydraulic oil sent to the hydraulic tool can be depressurized.
A mode selection unit is provided so that the operator can manually select the operation mode .
A pressure sensor that detects the pressure of hydraulic oil sent to the hydraulic tool, and
A controller that controls the electromagnetic switching valve while recognizing the pressure transition of the hydraulic oil based on the signal from the pressure sensor is provided.
The controller sets a threshold value according to the selection status of the mode selection unit, and controls the electromagnetic switching valve to guide the hydraulic oil to the boosting oil passage when it is determined that the pressure of the hydraulic oil exceeds the threshold value. A pressure boosting device for aerial work platforms, which switches from a state of operating oil to a state of guiding hydraulic oil to the decompression oil passage. The pressure booster for an aerial work platform according to claim 1, wherein the mode selection unit refers to a portion where the operating speed of the hydraulic tool can be selected by a manual operation of an operator. With hydraulic oil pump,
A plurality of drive sources capable of operating the hydraulic oil pump, and
The pressure booster for an aerial work platform according to claim 1, wherein the mode selection unit refers to a portion where the drive source for operating the hydraulic oil pump can be selected by a manual operation of an operator. .. With hydraulic oil pump,
A drive source for operating the hydraulic oil pump, and
The pressure booster for an aerial work platform according to claim 1, wherein the mode selection unit refers to a portion where the rotation speed of the drive source can be selected by a manual operation of an operator. With hydraulic oil pump,
The engine that operates the hydraulic oil pump is provided.
The pressure boosting device for an aerial work platform according to claim 1, wherein the mode selection unit refers to a portion where the rotation speed of the engine can be selected by automatic operation according to the volume of the engine. With hydraulic oil pump,
The motor that drives the hydraulic oil pump and
A battery that supplies electric power to the motor is provided.
The pressure boosting device for an aerial work platform according to claim 1, wherein the mode selection unit refers to a portion where the rotation speed of the motor can be selected by automatic operation according to the remaining amount of the battery. With hydraulic oil pump,
An engine that can operate the hydraulic oil pump and
Similarly, a motor that can operate the hydraulic oil pump and
A battery that supplies electric power to the motor is provided.
The first aspect of the present invention is characterized in that the mode selection unit refers to a portion where either the engine or the motor that operates the hydraulic oil pump by an automatic operation according to the remaining amount of the battery can be selected. The described pressure booster for aerial work platforms. The pressure boosting device for aerial work platforms according to claim 1, wherein the mode selection unit refers to a portion capable of selecting whether or not it is in a cold zone state by automatic operation according to the temperature of hydraulic oil.

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