JP2018059520A - Pressure intensifying device for work vehicle at high place - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure intensifying device capable of controlling pressure transition of hydraulic oil carried to a hydraulic tool and controlling maximum pressure of hydraulic oil.SOLUTION: A pressure intensifying device 12 for a work vehicle 1 used at high place includes a pressure sensor 14 configured to detect pressure of hydraulic oil fed to a crimp hydraulic tool 100, and a controller 31 configured to control an electromagnetic selector valve 24 with pressure transition of hydraulic oil on the basis of a signal from the pressure sensor 14. The controller 31 is configured to control the electromagnetic selector valve 24 to periodically repeat state of supplying hydraulic oil to a pressure intensifying oil passage 26 and a state of not supplying hydraulic oil to the pressure intensifying oil passage 26, in the middle of intensifying pressure of hydraulic oil fed to the hydraulic tool 100.SELECTED DRAWING: Figure 2

Description

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

  Conventionally, an aerial work vehicle including a bucket at the tip of a boom is known. In an aerial work platform, a hydraulic hose is guided to a bucket, and hydraulic oil can be supplied to a hydraulic tool connected to the hydraulic hose. Such an aerial work vehicle is provided with a pressure increasing device in order to increase the pressure of hydraulic oil sent to the hydraulic tool (see, for example, Patent Document 1).

The pressure increasing device includes a pressure increasing cylinder, a supply oil passage for supplying hydraulic oil to a pressure increasing chamber of the pressure increasing cylinder,
A pressure increasing oil passage that supplies hydraulic oil to the head side oil chamber of the pressure increasing cylinder, and an electromagnetic switching valve that switches between a state in which the operating oil is supplied to the pressure increasing oil passage and a state in which the operating oil is not supplied to the pressure increasing oil passage. It is equipped with. Then, when the electromagnetic switching valve supplies the hydraulic oil to the pressure-increasing oil passage, the hydraulic oil is pushed out from the pressure-increasing chamber and can be pressurized.

  Incidentally, the electromagnetic switching valve switches between a state in which hydraulic oil is supplied to the pressure-increasing oil passage and a state in which hydraulic oil is not supplied to the pressure-increasing oil passage, and directly controls the flow rate of the hydraulic oil sent to the hydraulic tool. It is not something to control. Therefore, in a hydraulic tool located at a position away from the electromagnetic switching valve, a response delay occurs even when switching from a state in which hydraulic oil is supplied to the pressure-increasing oil passage to a state in which hydraulic oil is not supplied to the pressure-increasing oil passage, This indicates a pressure transition in which the hydraulic oil pressure rises for a while and then drops. Therefore, a threshold value is set in anticipation that the maximum pressure of hydraulic oil in the hydraulic tool becomes higher than a specified value, and the electromagnetic switching valve is switched when the pressure exceeds the threshold value. However, there is a problem that a difference occurs in the pressure transition of the hydraulic oil sent to the hydraulic tool for some reason. As a result, there is a problem that a difference occurs in the maximum pressure of the hydraulic oil. Therefore, there has been a demand for a pressure intensifying device that can control the pressure transition of the hydraulic oil sent to the hydraulic tool, and thus can control the maximum pressure of the hydraulic oil.

JP 2014-20543 A

  Provided is a pressure intensifying device capable of controlling the transition of pressure of hydraulic oil sent to a hydraulic tool, and thereby controlling the maximum pressure of hydraulic oil.

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

The first invention is
A booster cylinder;
A supply oil passage for supplying hydraulic oil to the pressure increasing chamber of the pressure increasing cylinder;
A pressure increasing oil passage for supplying hydraulic oil to the head side oil chamber of the pressure increasing cylinder;
An electromagnetic switching valve for switching between a state in which hydraulic oil is supplied to the pressure-increasing oil passage and a state in which hydraulic oil is not supplied to the pressure-increasing oil passage;
When the electromagnetic switching valve supplies hydraulic oil to the pressure increase oil passage, the hydraulic oil is pushed out from the pressure increase chamber and the hydraulic oil sent to the hydraulic tool can be pressurized.
A pressure sensor for detecting the pressure of hydraulic fluid sent to the hydraulic tool;
A control device for controlling the electromagnetic switching valve while recognizing the pressure transition of the hydraulic oil based on a signal from the pressure sensor,
The control device periodically changes a state in which the hydraulic oil to be supplied to the hydraulic tool is being pressurized and a state in which the hydraulic oil is supplied to the pressure-increasing oil passage and a state in which hydraulic oil is not supplied to the pressure-increasing oil passage. The electromagnetic switching valve is controlled to repeat.

The second invention is a pressure booster for an aerial work vehicle according to the first invention,
The control device periodically repeats a state in which the operating oil is supplied to the pressure-increasing oil passage and a state in which the operating oil is not supplied to the pressure-increasing oil passage after determining that the pressure of the operating oil has exceeded a threshold value. In this way, the electromagnetic switching valve is controlled.

A third invention is a pressure booster for an aerial work vehicle according to the first or second invention,
The control device is configured to gradually increase the time during which no hydraulic oil is supplied to the pressure-increasing oil passage with respect to the time during which hydraulic oil is supplied to the pressure-increasing oil passage.

  In the pressure increasing device for an aerial work vehicle according to the first aspect of the invention, the control device is configured to supply the operating oil to the pressure increasing oil passage and to increase the pressure from the middle of increasing the operating oil sent to the hydraulic tool. The electromagnetic switching valve is controlled so as to periodically repeat the state of not supplying hydraulic oil to the oil passage. According to such a pressure booster for an aerial work vehicle, the electromagnetic switching valve can function as a flow control valve to adjust the flow rate of hydraulic oil sent to the pressure boosting cylinder, and as a result, the pressure boosting cylinder The amount of hydraulic oil pushed out from the chamber can also be adjusted as appropriate. Therefore, it is possible to control the pressure transition of the hydraulic oil sent to the hydraulic tool, and thus to control the maximum pressure of the hydraulic oil.

  In the pressure increasing device for an aerial work vehicle according to the second aspect of the invention, the control device determines that the pressure of the hydraulic oil has exceeded a threshold value, and supplies the hydraulic oil to the pressure increasing oil passage. The electromagnetic switching valve is controlled so as to periodically repeat the state of not supplying hydraulic oil to the road. According to such a pressure booster for an aerial work vehicle, when the pressure of the hydraulic oil is determined to exceed the threshold, the hydraulic oil is supplied to the pressure boosting cylinder while the electromagnetic switching valve functions as a flow control valve. As a result, the amount of hydraulic oil pushed out from the pressure increasing chamber of the pressure increasing cylinder can be adjusted as appropriate. Accordingly, it is possible to control the transition of the pressure of the hydraulic oil sent to the hydraulic tool while ensuring that the maximum pressure of the hydraulic oil in the hydraulic tool is higher than a specified value, and thus to control the maximum pressure of the hydraulic oil.

  In the pressure increasing device for an aerial work vehicle according to the third aspect of the invention, the control device does not supply the hydraulic oil to the pressure increasing oil passage with respect to the time for supplying the hydraulic oil to the pressure increasing oil passage. The length is gradually increased. According to such a pressure booster for an aerial work vehicle, the flow rate of the hydraulic oil sent to the pressure boosting cylinder can be controlled with high accuracy, and as a result, the amount of hydraulic oil pushed out from the pressure boosting chamber of the pressure boosting cylinder is appropriately and high. It can be adjusted to accuracy. Therefore, it is possible to control the pressure transition of the hydraulic oil sent to the hydraulic tool, and thus to control the maximum pressure of the hydraulic oil.

The figure which shows an aerial work vehicle. The figure which shows the structure of a pressure booster. The figure which shows the flow direction of the hydraulic fluid at the time of temporary holding operation | movement. The figure which shows the flow direction of the hydraulic fluid in the preload stage at the time of this compression operation | movement. The figure which shows the flow direction of the hydraulic fluid in the main pressure stage at the time of this compression operation. The figure which shows the flow direction of the hydraulic fluid at the time of return operation | movement. The figure which shows the operation | movement aspect of a hydraulic crimping tool. The figure which shows the control system of a pressure booster. The figure which shows the control aspect of a booster. The figure which shows the control aspect of a booster. The figure which shows the control aspect of a booster. The figure which shows the control aspect of a booster. The figure which shows the control aspect of a booster.

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

  The aerial work vehicle 1 is used for wiring work in which a power line is connected by crimping a sleeve. The aerial work vehicle 1 has an aerial work device 6 on a vehicle 2.

  The vehicle 2 conveys the aerial work device 6. The vehicle 2 is provided with a driver's cab and a plurality of wheels 3 and further has an engine 4 mounted thereon. The vehicle 2 travels by transmitting the driving force of the engine 4 to the wheels 3. In addition, the vehicle 2 includes an outrigger 5. The outrigger 5 includes 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 widen the work range of the aerial work device 6 by operating the outrigger 5.

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

  The swivel base 7 turns 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 be turnable around the center of the annular bearing as a turning center. The swivel base 7 is swung by a hydraulic actuator (not shown).

  The telescopic boom 8 moves up and down the bucket 9. The telescopic boom 8 has a structure in which each constituent member has a rectangular tube shape and is accommodated in order from the largest to the inside. The telescopic boom 8 is expanded and contracted by an expansion cylinder (not shown). The telescopic boom 8 has a base end attached to the swivel base 7 so as to be swingable.

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

  The hoisting cylinder 10 is for raising or lowering the telescopic boom 8. The hoisting cylinder 10 has a base end portion that is swingably connected to the swivel base 7, and a distal end portion that is swingably connected to the telescopic boom 8. The hoisting cylinder 10 erects the telescopic boom 8 by extending itself. Further, the hoisting cylinder 10 causes the telescopic boom 8 to fall down by contracting itself.

  The operating device 11 is for operating the swivel base 7, the telescopic boom 8, the bucket 9, and the like. The operating device 11 is provided in the rear part of the vehicle 2 and in the bucket 9. The operating device 11 has a bucket maneuvering unit 41 for instructing turning, telescopic, undulation or the like of the telescopic boom 8.

  Next, the pressure booster 12 will be described with reference to FIG.

  The pressure increasing device 12 includes a pressure increasing cylinder 13, a pressure sensor 14, a preloading electromagnetic switching valve (hereinafter referred to as “preloading switching valve”) 17, a relief valve 21, and a main pressure electromagnetic switching valve (hereinafter referred to as “switching valve”). 24), a pilot 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 control device 31 (see FIG. 8).

  The pressure increasing cylinder 13 is for increasing the pressure of hydraulic oil. The pressure increasing cylinder 13 has a structure in which a large-diameter cylinder and a small-diameter cylinder are connected, and a large-diameter piston 13d is slidably accommodated inside the large-diameter cylinder. For this reason, a head side oil chamber 13c is configured on the head side of the large diameter piston 13d, and a rod side oil chamber 13b is configured on the rod side of the large diameter piston 13d. A small diameter piston 13e is slidably accommodated in the small diameter cylinder. For this reason, the pressure increasing chamber 13a is comprised by one side of the small diameter piston 13e. The large-diameter piston 13d and the small-diameter piston 13e are connected via a rod 13f. Therefore, when the hydraulic oil is supplied to the head side oil chamber 13c, the pressure increasing cylinder 13 transmits the force applied to the large diameter piston 13d to the small diameter piston 13e. Thereby, the pressure increasing cylinder 13 pushes out the hydraulic oil in the pressure increasing chamber 13a by the force calculated by the area ratio of the large diameter piston 13d and the small diameter piston 13e, and consequently increases the hydraulic oil sent to the hydraulic tool 100. .

  The pressure sensor 14 detects the pressure of the hydraulic oil sent to the hydraulic tool 100. In the pressure increasing device 12, the pressure sensor 14 is attached to the pressure increasing chamber 13 a of the pressure increasing cylinder 13. However, it may be attached to an appropriate position of the supply oil passage 15 for supplying the hydraulic oil to the pressure increasing chamber 13a. Note that a hydraulic hose 16 is connected to the supply oil passage 15 in the middle thereof. For this reason, hydraulic fluid can be supplied to the hydraulic tool 100 connected to the hydraulic hose 16.

  The preload switching valve 17 supplies hydraulic oil to the low pressure oil passage 18 or the preload oil passage 19. In the preload switching valve 17, one of the one port and the other port is communicated with the supply port when a spool (not shown) slides. One port of the preload switching valve 17 is connected to the supply oil passage 15 via a low pressure oil passage 18. The other port of the preload switching valve 17 is connected to the supply oil passage 15 via a preload oil passage 19. A hydraulic oil pump 28 is connected to the supply port of the preload switching valve 17 via the discharge oil passage 20. For this reason, 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 end 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 discharge oil passage. For this reason, when the pressure of the hydraulic oil flowing through the low pressure oil passage 18 exceeds a set value, the leaf valve 21 can discharge a part of the hydraulic oil 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 upstream of the branch point. In addition, a check valve 23 is arranged in the other middle portion branched from the low pressure oil passage 18 and in the middle portion of the preload oil passage 19.

  Here, assuming that the electromagnet of the preload switching valve 17 is not excited (when no signal is received from the control device 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 the state is reached. That is, the preload switching valve 17 is switched to a state in which the hydraulic oil sent out by the hydraulic oil pump 28 is not supplied to the supply oil passage 15.

  Further, assuming that the electromagnet is excited so that one port of the preload switching valve 17 communicates with the supply port (when a signal is received from the control device 31 to supply low-pressure hydraulic oil), the low pressure The spool is moved to the I position where the oil passage 18 and the discharge oil passage 20 are communicated 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 supply oil passage 15 through the low pressure oil passage 18. At this time, low pressure hydraulic oil is supplied to the pressure increasing chamber 13 a of the pressure increasing cylinder 13 through the supply 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 a signal is received from the control device 31 to supply hydraulic oil for preload), the preload is assumed. The spool is moved to a position III where the oil passage 19 and the discharge oil passage 20 are communicated 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 the working oil is supplied to the supply oil passage 15 through the preload oil passage 19. At this time, the preload hydraulic fluid is supplied to the pressure increasing chamber 13 a of the pressure increasing cylinder 13 through the supply oil passage 15.

  The main pressure switching valve 24 supplies hydraulic oil to the pressure increasing oil passage 26 or the pressure reducing oil passage 25. In the main pressure switching valve 24, one of the one port and the other port is communicated with the supply port when a spool (not shown) slides. One port of the main pressure switching valve 24 is connected to the head side oil chamber 13 c of the pressure increasing cylinder 13 via the pressure increasing oil passage 26. The other port of the main pressure switching valve 24 is connected to the rod-side oil chamber 13 b of the pressure-increasing cylinder 13 through 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 the discharge oil passage 20. For this reason, the hydraulic oil is supplied to the pressure-increasing oil passage 26 and the pressure-reducing 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 no signal is received from the control device 31), the pressure increasing 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 the state is reached. That is, the main pressure switching valve 24 is switched to a state in which the hydraulic oil delivered from 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 increasing cylinder 13.

  Further, assuming that the electromagnet is excited so that one port of the main pressure switching valve 24 communicates with the supply port (when a signal is received from the control device 31 to increase the hydraulic oil pressure), the increase is assumed. The spool is moved to a position III where the pressure oil passage 26 and the discharge oil passage 20 communicate with each other and the pressure reduction 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 13 c of the pressure increasing cylinder 13 through the pressure increasing oil passage 26. At this time, in the pressure increasing cylinder 13, the small diameter piston 13e slides in one direction together with the large diameter piston 13d and the volume of the pressure increasing chamber 13a is reduced, so that the hydraulic oil is pushed out from the pressure increasing chamber 13a.

  Further, assuming that the electromagnet is excited so that the other port of the main pressure switching valve 24 communicates with the supply port (when a signal is received from the control device 31 to reduce the hydraulic oil pressure), 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 and the pressure-increasing oil passage 26 is connected to the hydraulic oil tank 30. That is, the main pressure switching valve 24 is switched to a state where hydraulic oil is supplied to the rod side oil chamber 13 b of the pressure increasing cylinder 13 through the pressure reducing oil passage 25. At this time, in the pressure-increasing cylinder 13, the small-diameter piston 13e slides to the other side together with the large-diameter piston 13d, and the volume of the pressure-increasing chamber 13a is expanded, so that hydraulic oil is drawn into the pressure-increasing chamber 13a.

  The pilot check valve 27 releases the supply oil passage 15. The pilot check valve 27 is connected to the end portion of the supply oil passage 15. The pilot check valve 27 is connected to the hydraulic oil tank 30 via a discharge oil passage. The pilot check valve 27 is supplied with pilot hydraulic oil from the pressure reducing oil passage 25. Therefore, when the main pressure switching valve 24 is switched to a state in which hydraulic oil is supplied to the rod-side oil chamber 13 b of the pressure increasing cylinder 13, the pilot check valve 27 removes a part of the hydraulic oil in the supply oil passage 15. It can be discharged to the hydraulic oil tank 30. Accordingly, the hydraulic oil in the supply oil passage 15 is quickly discharged without being sent to the hydraulic 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. A hydraulic oil relief valve 29 is disposed in the discharge oil passage 20. The hydraulic oil relief valve 29 restricts the pressure of the hydraulic oil delivered from 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 flow direction of the hydraulic oil in the pressure booster 12 will be described with reference to FIGS. Hereinafter, it is assumed that the hydraulic tool 100 is the hydraulic crimping tool 100, and the operation mode thereof will also be described.

  The hydraulic crimping tool 100 grips the sleeve S and crimps it. In the hydraulic crimping tool 100, the movable part 100 a moves toward the receiving part 100 b by the hydraulic oil sent from the pressure booster 12. The hydraulic pressure bonding tool 100 is provided with a head hose 100c, and hydraulic oil is supplied through the head hose 100c. The head hose 100c is connected to the hydraulic hose 16 described above.

  As shown in FIG. 7, the hydraulic crimping tool 100 includes a stop operation s0 in which the movable portion 100a stops, a temporary holding operation s1 in which the movable portion 100a moves toward the receiving portion 100b and grips the sleeve S, and is movable. A preload stage s2 of the main compression operation in which the portion 100a moves with a predetermined force and applies a preload to the sleeve S, and a main compression operation book in which the movable portion 100a moves with a predetermined force and applies a main pressure load to the sleeve S. A pressure stage s3 and a return operation s4 for releasing the sleeve S by moving the movable part 100a away from the receiving part 100b are performed.

  As shown in FIG. 2, when the hydraulic crimping tool 100 performs the stop operation s0, the control device 31 sets the spool position of the preload switching valve 17 so that the low pressure oil passage 18 and the preload oil passage 19 are hydraulic oil tanks. And move to the II position where it is connected to 30. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the II position where 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 in a state where the movable part 100a is separated from the receiving part 100b.

  As shown in FIG. 3, when the hydraulic pressure bonding tool 100 performs the temporary holding operation s <b> 1, the control device 31 connects the low pressure oil passage 18 to the discharge oil passage 20 at the spool position of the preload switching valve 17. The preload oil passage 19 is moved to the I position where it is connected to the hydraulic oil tank 30. However, the control device 31 maintains the spool position of the main pressure switching valve 24 at the II position where the pressure increasing oil passage 26 and the pressure reducing oil passage 25 are connected to the hydraulic oil tank 30. Thereby, the hydraulic crimping tool 100 can grip the sleeve S because the movable part 100a moves toward the receiving part 100b by the low-pressure hydraulic oil.

  As shown in FIG. 4, when the hydraulic crimping tool 100 performs the preload stage s <b> 2 of the main compression operation, the control device 31 sets the spool position of the preload switching valve 17 to the preload oil path 19 and the discharge oil path 20. To the position III where the low-pressure oil passage 18 is connected to the hydraulic oil tank 30. However, the control device 31 maintains the spool position of the main pressure switching valve 24 at the II position where the pressure increasing oil passage 26 and the pressure reducing oil passage 25 are connected to the hydraulic oil tank 30. Thereby, the hydraulic crimping tool 100 can apply a preload to the sleeve S because the movable portion 100a moves toward the receiving portion 100b by the preload hydraulic oil.

  As shown in FIG. 5, when the hydraulic crimping tool 100 performs the main pressure stage s3 of the main compression operation, the control device 31 sets the spool position of the preload switching valve 17 to the low pressure oil path 18 and the preload oil path. 19 is moved to the II position where the hydraulic oil tank 30 is connected. At the same time, the control device 31 moves the spool position of the main pressure switching valve 24 to the position III where 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. Let Thereby, the hydraulic pressure bonding tool 100 can apply a main pressure load to the sleeve S because the movable portion 100a moves toward the receiving portion 100b by the pressurized hydraulic oil. At this time, the sleeve S can be caulked.

  As shown in FIG. 6, when the hydraulic crimping tool 100 performs the return operation s4, the control device 31 sets the spool position of the preload switching valve 17 to the low pressure oil passage 18 and the preload oil passage 19 in the hydraulic oil tank. It is maintained at the II position where it is connected to 30. However, the control device 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. Let Thereby, the hydraulic crimping tool 100 is moved by the spring so that the movable part 100a is separated from the receiving part 100b, and thus 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 13.

  As shown in FIG. 8, the control device 31 mainly controls the preload switching valve 17 and the main pressure switching valve 24 that constitute the pressure increasing device 12. In addition to the rotational speeds of the engine 4 and the motor 32, the control device 31 can also control the engine clutch 4C and the motor clutch 32C that transmit these driving forces. Furthermore, the control device 31 can also acquire a signal from the pressure sensor 14. The control device 31 may be configured such that a CPU, ROM, RAM, HDD, or the like is connected by a bus, or may be configured from a one-chip LSI or the like.

  First, in order to clarify the superiority of the present invention, a conventional control mode will be described.

  FIG. 9A is a graph showing the pressure transition of the hydraulic oil sent to the hydraulic crimping tool 100. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the pressure of hydraulic oil sent to the hydraulic crimping tool 100. On the other hand, FIG. 9B is a graph showing the transition of the excitation state of the electromagnet of the main pressure switching valve 24. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the excitation state of the electromagnet of the main pressure switching valve 24. When the excitation state is ON, the hydraulic oil is supplied to the pressure increase oil passage 26, and when the excitation state is OFF, the hydraulic oil is not supplied to the pressure increase oil passage 26.

  The pressure transition (see the pressure transition La) in the conventional control mode rises high at the main pressure stage s3 of the main compression operation described above. Thereafter, the control device 31 reduces the pressure by switching from the state in which the operating oil is supplied to the pressure-increasing oil passage 26 to the state in which the operating oil is not supplied to the pressure-increasing oil passage 26 (see excitation state transition Da). . At this time, in the hydraulic pressure bonding tool 100 at a position away from the main pressure switching valve 24, the state is switched from the state in which the hydraulic oil is supplied to the pressure increasing oil passage 26 to the state in which the hydraulic oil is not supplied to the pressure increasing oil passage 26. However, a response delay occurs, and the pressure transition is such that the hydraulic oil pressure rises for a while and then drops. Accordingly, a threshold Pa is set in anticipation that the maximum pressure of the hydraulic oil in the hydraulic crimping tool 100 is higher than a specified value, and the main pressure switching valve 24 is switched when the pressure exceeds the threshold Pa. is there. However, for some reason, there is a difference in the pressure transition of the hydraulic oil sent to the hydraulic pressure bonding tool 100, and thus there is a difference in the maximum pressure of the hydraulic oil. For example, when the amount of hydraulic oil sent from the hydraulic oil pump 28 is large (see the pressure transition Lb), the maximum pressure becomes higher than the target pressure P (see arrow A), and the hydraulic oil amount sent from the hydraulic oil pump 28 is When the amount is small (see pressure transition Lc), the maximum pressure sometimes becomes lower than the target pressure P (see arrow B).

  Next, the control aspect of 1st embodiment of this invention is demonstrated.

  FIG. 10A is a graph showing the pressure transition of the hydraulic oil sent to the hydraulic crimping tool 100. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the pressure of hydraulic oil sent to the hydraulic crimping tool 100. On the other hand, FIG. 10B is a graph showing the excitation state of the main pressure switching valve 24. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the excitation state of the electromagnet of the main pressure switching valve 24. When the excitation state is ON, the hydraulic oil is supplied to the pressure increase oil passage 26, and when the excitation state is OFF, the hydraulic oil is not supplied to the pressure increase oil passage 26.

  In the control mode of the first embodiment of the present invention, the control device 31 performs predetermined control so that the maximum pressure of the hydraulic oil becomes the target pressure P (see pressure transition Ld). That is, the control device 31 supplies the hydraulic oil to the pressure-increasing oil passage 26 and does not supply the hydraulic oil to the pressure-increasing oil passage 26 while the hydraulic oil sent to the hydraulic pressure bonding tool 100 is being increased. The main pressure switching valve 24 is controlled so as to be repeated periodically. In this control mode, the excitation state is ON and OFF is periodically repeated at a constant time ratio (duty ratio) (see excitation state transition Dd). The time ratio is preferably changed according to the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. For example, it may be changed between 7: 3 and 3: 7 according to the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. Further, it may be changed according to the temperature (viscosity) of the hydraulic oil.

  As described above, the control device 31 supplies the hydraulic oil to the pressure-increasing oil path 26 and the pressure-increasing oil path 26 from the middle of increasing the pressure of the hydraulic oil sent to the hydraulic tool (hydraulic pressure bonding tool 100). The electromagnetic switching valve (main pressure switching valve 24) is controlled so as to periodically repeat the state in which no hydraulic oil is supplied. According to the pressure increasing device 12 for such an aerial work vehicle 1, the electromagnetic switching valve (24) can function as a flow control valve to adjust the flow rate of hydraulic fluid sent to the pressure increasing cylinder 13, and as a result. The amount of hydraulic oil pushed out from the pressure increasing chamber 13a of the pressure increasing cylinder 13 can also be adjusted appropriately. Therefore, the pressure transition of the hydraulic oil sent to the hydraulic tool (100) can be controlled, and the maximum pressure of the hydraulic oil can be controlled.

  Next, the control aspect of 2nd embodiment of this invention is demonstrated.

  FIG. 11A is a graph showing the pressure transition of the hydraulic oil sent to the hydraulic crimping tool 100. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the pressure of hydraulic oil sent to the hydraulic crimping tool 100. On the other hand, FIG. 11B is a graph showing the excitation state of the main pressure switching valve 24. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the excitation state of the electromagnet of the main pressure switching valve 24. When the excitation state is ON, the hydraulic oil is supplied to the pressure increase oil passage 26, and when the excitation state is OFF, the hydraulic oil is not supplied to the pressure increase oil passage 26.

  In the control mode of the second embodiment of the present invention, the control device 31 performs predetermined control so that the maximum pressure of the hydraulic oil becomes the target pressure P after determining that the pressure of the hydraulic oil has exceeded the threshold value Pa. (See pressure transition Le). That is, the control device 31 controls the main pressure switching valve 24 so as to periodically repeat the state in which the operating oil is supplied to the pressure-increasing oil passage 26 and the state in which the operating oil is not supplied to the pressure-increasing oil passage 26. . Also in this control mode, the excitation state is ON and the OFF state is periodically repeated at a constant time ratio (duty ratio) (see excitation state transition De). The time ratio is preferably changed according to the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. For example, it may be changed between 7: 3 and 3: 7 according to the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. Further, it may be changed according to the temperature (viscosity) of the hydraulic oil.

  As described above, when the control device 31 determines that the pressure of the hydraulic oil has exceeded the threshold value Pa, a state in which the hydraulic oil is supplied to the pressure increasing oil passage 26 and a state in which the hydraulic oil is not supplied to the pressure increasing oil passage 26. The electromagnetic switching valve (main pressure switching valve 24) is controlled so as to be repeated periodically. According to the pressure booster 12 for the aerial work vehicle 1, the electromagnetic switching valve (24) functions as a flow control valve to increase the pressure after determining that the pressure of the hydraulic oil has exceeded the threshold value Pa. The flow rate of the hydraulic oil sent to the cylinder can be adjusted, and as a result, the amount of hydraulic oil pushed out from the pressure increasing chamber 13a of the pressure increasing cylinder 13 can be adjusted appropriately. Accordingly, it is possible to control the transition of the pressure of the hydraulic oil sent to the hydraulic tool (100) while ensuring that the maximum pressure of the hydraulic oil in the hydraulic tool (100) is higher than a specified value, and thus to increase the maximum pressure of the hydraulic oil. Can be controlled.

  Next, the control aspect of 3rd embodiment of this invention is demonstrated.

  (A) of FIG. 12 is a graph showing the pressure transition of the hydraulic fluid sent to the hydraulic crimping tool 100. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the pressure of hydraulic oil sent to the hydraulic crimping tool 100. On the other hand, FIG. 12B is a graph showing the excitation state of the main pressure switching valve 24. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the excitation state of the electromagnet of the main pressure switching valve 24. When the excitation state is ON, the hydraulic oil is supplied to the pressure increase oil passage 26, and when the excitation state is OFF, the hydraulic oil is not supplied to the pressure increase oil passage 26.

  In the control mode of the third embodiment of the present invention, the control device 31 performs predetermined control so that the maximum pressure of the hydraulic oil becomes the target pressure P (see the pressure transition Lf). That is, the control device 31 supplies the hydraulic oil to the pressure-increasing oil passage 26 and does not supply the hydraulic oil to the pressure-increasing oil passage 26 while the hydraulic oil sent to the hydraulic pressure bonding tool 100 is being increased. And the main pressure switching valve 24 so that the time when the hydraulic oil is not supplied to the pressure-increasing oil passage 26 is gradually increased with respect to the time when the hydraulic oil is supplied to the pressure-increasing oil passage 26. Is controlled. In this control mode, the time ratio (duty ratio) between the ON state and the OFF state of the excitation state gradually changes, that is, the OFF state increases with respect to the excitation state. The excitation state is periodically turned on and off (see excitation state transition Df). The time ratio is preferably changed according to the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. For example, it may be gradually changed between 7: 3 and 0:10 in accordance with the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. Further, it may be changed according to the temperature (viscosity) of the hydraulic oil.

  As described above, the control device 31 gradually increases the time during which no hydraulic oil is supplied to the pressure increasing oil passage 26 with respect to the time when the hydraulic oil is supplied to the pressure increasing oil passage 26. According to the pressure increasing device 12 for the aerial work vehicle 1, the flow rate of the hydraulic oil sent to the pressure increasing cylinder 13 can be controlled with high accuracy, and as a result, the hydraulic oil pushed out from the pressure increasing chamber 13 a of the pressure increasing cylinder 13. The amount can be adjusted appropriately and with high accuracy. Therefore, the pressure transition of the hydraulic oil sent to the hydraulic tool (100) can be controlled, and the maximum pressure of the hydraulic oil can be controlled.

  Next, the control aspect of 4th embodiment of this invention is demonstrated.

  FIG. 13A is a graph showing the pressure transition of the hydraulic oil sent to the hydraulic crimping tool 100. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the pressure of hydraulic oil sent to the hydraulic crimping tool 100. On the other hand, FIG. 13B is a graph showing the excitation state of the main pressure switching valve 24. The horizontal axis of the graph represents time, and the vertical axis of the graph represents the excitation state of the electromagnet of the main pressure switching valve 24. When the excitation state is ON, the hydraulic oil is supplied to the pressure increase oil passage 26, and when the excitation state is OFF, the hydraulic oil is not supplied to the pressure increase oil passage 26.

  In the control mode of the fourth embodiment of the present invention, the control device 31 performs predetermined control so that the maximum pressure of the hydraulic oil becomes the target pressure P after determining that the pressure of the hydraulic oil has exceeded the threshold value Pa. (Refer to pressure transition Lg). That is, the control device 31 periodically repeats the state in which the operating oil is supplied to the pressure-increasing oil passage 26 and the state in which the operating oil is not supplied to the pressure-increasing oil passage 26, and supplies the operating oil to the pressure-increasing oil passage 26. The main pressure switching valve 24 is controlled so that the time when the hydraulic oil is not supplied to the pressure increasing oil passage 26 gradually increases with respect to the time of the state. Also in this control mode, the time ratio (duty ratio) between the excitation state of ON and OFF state gradually changes, that is, the OFF state becomes larger with respect to the excitation state of ON, The excitation state is periodically turned on and off (see excitation state transition Dg). The time ratio is preferably changed according to the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. For example, it may be gradually changed between 7: 3 and 0:10 in accordance with the amount of hydraulic oil per unit time sent out by the hydraulic oil pump 28. Further, it may be changed according to the temperature (viscosity) of the hydraulic oil.

  As described above, the control device 31 determines that the hydraulic oil pressure has exceeded the threshold value Pa and then supplies the hydraulic oil to the pressure-increasing oil passage 26 with respect to the time during which the hydraulic oil is supplied to the pressure-increasing oil passage 26. Gradually lengthen the time during which no water is supplied. According to the pressure booster 12 for the aerial work vehicle 1, the flow rate of the hydraulic oil sent to the pressure booster cylinder 13 can be controlled with high accuracy from the time when it is determined that the pressure of the hydraulic oil has exceeded the threshold value Pa. As a result, the amount of hydraulic oil pushed out from the pressure increasing chamber 13a of the pressure increasing cylinder 13 can also be adjusted appropriately and with high accuracy. Accordingly, it is possible to control the transition of the pressure of the hydraulic oil sent to the hydraulic tool (100) while ensuring that the maximum pressure of the hydraulic oil in the hydraulic tool (100) is higher than a specified value, and thus to increase the maximum pressure of the hydraulic oil. Can be controlled.

  The above-described embodiments are merely representative, and various modifications can be made without departing from the configuration of the embodiment.

DESCRIPTION OF SYMBOLS 1 High-altitude work vehicle 12 Booster 13 Booster cylinder 13a Booster chamber 13c Head side oil chamber 14 Pressure sensor 15 Supply oil path 24 Main pressure switching valve (electromagnetic switching valve)
26 Pressure increase oil passage 31 Control device 100 Hydraulic crimping tool (hydraulic tool)

Claims (3)

A booster cylinder;
A supply oil passage for supplying hydraulic oil to the pressure increasing chamber of the pressure increasing cylinder;
A pressure increasing oil passage for supplying hydraulic oil to the head side oil chamber of the pressure increasing cylinder;
An electromagnetic switching valve for switching between a state in which hydraulic oil is supplied to the pressure-increasing oil passage and a state in which hydraulic oil is not supplied to the pressure-increasing oil passage;
When the electromagnetic switching valve supplies hydraulic oil to the pressure increase oil passage, the hydraulic oil is pushed out from the pressure increase chamber and the hydraulic oil sent to the hydraulic tool can be pressurized.
A pressure sensor for detecting the pressure of hydraulic fluid sent to the hydraulic tool;
A control device for controlling the electromagnetic switching valve while recognizing the pressure transition of the hydraulic oil based on a signal from the pressure sensor,
The control device controls the electromagnetic switching valve to supply the hydraulic oil to the pressure-increasing oil path and the hydraulic oil to the pressure-increasing oil path while increasing the pressure of the hydraulic oil sent to the hydraulic tool. A pressure booster for an aerial work vehicle, characterized by periodically repeating the state of not supplying the engine.   The control device controls the electromagnetic switching valve to supply the hydraulic oil to the pressure-increasing oil passage and supply the hydraulic oil to the pressure-increasing oil passage after determining that the pressure of the hydraulic oil has exceeded a threshold value. The pressure increasing device for an aerial work vehicle according to claim 1, wherein the non-operating state is periodically repeated.   2. The control device according to claim 1, wherein the controller gradually increases a state in which the hydraulic oil is not supplied to the pressure-increasing oil passage with respect to a state in which the hydraulic oil is supplied to the pressure-increasing oil passage. Item 3. A pressure booster for an aerial work vehicle according to Item 2.