KR102078486B1 - Boom hoist and boom sprayer - Google Patents

Abstract

The boom lifting device includes a lifting platform 3 capable of lifting up and down the body 91, a boom 4 supported on the lifting platform, a lifting cylinder 40 interposed between the body and the lifting platform, and a working fluid to the lifting cylinder. The on-off valve 63 for opening and closing the working fluid supply and discharge device 50 for supplying and discharging the gas, the accumulator 61 connected to the lifting cylinder, the passage communicating the lifting cylinder and the accumulator, and the on / off valve according to the operator's operation. The controller 70 is provided. The controller closes the on-off valve when detecting an operation of raising and lowering the boom by the operator.

Description

Boom hoist and boom sprayer

The present invention relates to a boom lifting device and a boom lifting device for lifting and lowering the boom of the boom sprayer.

JP2013-102A includes a link arm installed on a vehicle body, a boom having one end supported by the link arm, a cylinder interposed between the vehicle body and the link arm, and a boom elevating device for elevating the boom by supplying hydraulic oil to the cylinder. A boom sprayer provided is disclosed.

In addition, in the boom sprayer described in JP2013-102A, an accumulator for absorbing pressure fluctuations in the cylinder is connected to the cylinder in order to suppress the vibration of the vehicle body from being transmitted to the boom. The pressure in the accumulator is usually equal to the pressure in the piston side chamber of the cylinder. The pressure of the piston side chamber is a pressure necessary for maintaining the boom at a predetermined height with respect to the vehicle body, that is, the pressure according to the weight of a member such as a link arm or a boom lifted and supported by the cylinder.

In the boom sprayer described in JP2013-102A, when the boom extends to the left and right of the vehicle body and tries to raise the boom in a stationary state, an inertial force acts on the boom. For this reason, in order to raise a boom quickly with respect to a vehicle body, in addition to the load which supports a boom, the load which exceeds the inertia force acting on a boom must be produced to a cylinder. That is, it is necessary to raise the pressure of the piston side chamber of the cylinder from the pressure at the time of supporting the boom in the stopped state by the amount corresponding to the inertia force acting on the boom.

Here, in the boom sprayer of JP2013-102A, the piston side chamber and the accumulator communicate. For this reason, even if it tries to raise the pressure of a piston side chamber by supplying hydraulic fluid from a pump, hydraulic fluid flows into the oil chamber of the accumulator which communicates with a piston side chamber, and contracts the accumulator's spring chamber. As the spring chamber contracts, the pressure in the piston side chamber gradually increases as the accumulator pressure increases. When the pressure in the piston side chamber rises by the minute corresponding to the inertia force acting on the boom, the cylinder extends and raises the boom with respect to the vehicle body.

As described above, in the boom sprayer of the above configuration, the boom does not rise unless the accumulator pressure rises, so there is a fear that the boom does not rise quickly even if the operator makes an operation of raising the boom.

An object of this invention is to improve the responsiveness to the lifting operation of a boom of a boom sprayer.

According to one aspect of the present invention, there is provided an elevating member capable of elevating a vehicle body, a boom whose one end is supported by the elevating member, the other end is provided as a free end, and interposed between the vehicle body and the elevating member. A hydraulic cylinder, a working fluid supplying and discharging device for supplying and dispensing a working fluid to and from the hydraulic cylinder, an accumulator connected to the hydraulic cylinder and storing a pressurized working fluid, and the hydraulic cylinder. And an opening / closing valve for opening and closing a passage communicating with the accumulator, and a control unit for controlling the opening / closing valve in accordance with an operator's operation. A boom lifting device is provided for closing the valve.

1 is a plan view of a boom sprayer according to the first embodiment of the present invention.
2 is a hydraulic circuit diagram of the boom elevating device and a side view of the boom sprayer.
It is a flowchart of the boom lifting processing which the control part of the boom sprayer which concerns on 1st Embodiment of this invention performs.
It is a flowchart of the modification of the boom lifting processing which the control part of the boom sprayer which concerns on 1st Embodiment of this invention performs.
5 is a side view of a hydraulic circuit diagram and a boom sprayer of the boom lifting device according to the second embodiment of the present invention.
It is a flowchart of the boom lifting processing which the control part of the boom sprayer which concerns on 2nd Embodiment of this invention performs.
It is a flowchart of the modification of the boom lifting processing which the control part of the boom sprayer which concerns on 2nd Embodiment of this invention performs.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to an accompanying drawing. In addition, three axes of X, Y, and Z orthogonal to each other are set on the accompanying drawings, and the X axis is the front and rear direction (approximately horizontal and vertical direction) of the vehicle, and the Y axis is the left and right direction (approximately horizontal and horizontal direction) and Z axis of the vehicle. The embodiment will be described with the vehicle extending in the vertical direction (approximately the vertical direction), the rotational direction around the X axis as the roll direction, and the rotational direction around the Z axis as the yaw direction.

<1st embodiment>

First, with reference to FIG. 1 and FIG. 2, the boom sprayer 100 which concerns on 1st Embodiment of this invention is demonstrated.

The boom sprayer 100 shown in FIG. 1 is an agricultural work machine mounted on the front side of the work vehicle 90 which runs a pavement, and sprays chemical liquids, such as a control liquid and a liquid fertilizer, from the work vehicle 90. FIG.

The boom sprayer 100 includes a pair of booms 4 extending from the work vehicle 90 to the left and right. The boom 4 is provided with a nozzle (not shown) which sprays a chemical liquid. During operation of the boom sprayer 100, the chemical liquid is sprayed from the nozzle of the boom 4 while the work vehicle 90 travels the package.

The boom sprayer 100 is a pair of link arms 2 provided on the vehicle body 91 of the work vehicle 90, and a lifting member supported by the link arm 2 to be able to lift and lower the vehicle body 91. Platform 3 as a stand, a roll table 5 rotatably supported in the roll direction (around X axis) with respect to the platform 3, and from the roll table 5 to the left and right sides (Y-axis direction) of the vehicle body 91. The left and right booms 4 are provided.

The boom 4 is cantilevered rotatably with respect to the roll base 5 in the yaw direction (around Z-axis) through the storage hinge (not shown), and the free end part 4b is do. The boom 4 is supported by the proximal end frame 15 having the proximal end 4a so that the proximal end frame 16 having the proximal end 4b is elastically supported.

In FIG. 1, the expanded state in which the left and right booms 4 extended in the left-right horizontal direction of the vehicle body 91 is shown. When storing the boom 4, the boom 4 contracts the leading end frame 16 from the expanded state shown in FIG. 1 and stores it in the proximal end frame 15, and then rotates backward through the storing hinge. do. As a result, the boom 4 is folded and stored so as to extend in the front-rear direction along the side of the vehicle body 91.

The roll stand 5 is rotatably supported by the lifting platform 3 via the support shaft 6 in the roll direction. As the support shaft 6, a cylindrical pin member is used.

Between the platform 3 and the roll 5, the fluid pressure cylinder 30 which expands and contracts with the boom 4 rotating in the left-right roll direction, and the fluid pressure cylinder 30 between the support shafts 6 It is provided in the position which becomes symmetrical to 30, and the metal spring 32 which expands and contracts with the rotation of the boom 4 in a left-right roll direction is provided. The hydraulic cylinder 30 and the metal spring 32 suppress vibration in the roll direction in which the boom 4 rotates in the left and right roll directions. As a result, vibrations in which the tip portion 4b of the boom 4 shakes in the vertical direction are suppressed, and the tip portion 4b is prevented from contacting the crops of the package or the like.

Next, with reference to FIG. 2, the mechanism which raises and lowers the boom 4 with respect to the vehicle body 91 is demonstrated. 2 is a side view of the boom sprayer 100.

The link arm 2 has an upper link 21 and a lower link 22 extending in parallel with each other. The upper link 21 has its proximal end rotatably connected to the vehicle body 91 via the pin 12, and its distal end rotatably connected to the platform 3 via the pin 11. The lower link 22 has its proximal end rotatably connected to the vehicle body 91 via the pin 14, and its distal end rotatably connected to the platform 3 via the pin 13.

On both left and right sides of the vehicle body 91, a pair of lifting cylinders 40 as hydraulic cylinders are provided. Each lifting cylinder 40 is interposed between the vehicle body 91 and the upper link 21, and expands and lowers the lifting table 3 and the boom 4 by synchronously expanding.

The lifting cylinder 40 includes a cylinder tube 41 in which hydraulic oil as a working fluid is sealed, a piston rod 42 inserted into the cylinder tube 41 so as to be retracted and a piston provided at the proximal end of the piston rod 42. 43 is provided. The lifting cylinder 40 has a proximal end of the cylinder tube 41 rotatably connected to the vehicle body 91 through a pillow ball 46, and an upper end of the piston rod 42 via a pillow ball 47. It is rotatably connected to 21. The pillow balls 46 and 47 are comprised by a ball and spherical bearing, for example. The connection part of the lifting cylinder 40 is prevented from twisting by the pillow balls 46 and 47.

The inside of the cylinder tube 41 is partitioned into the piston side chamber 44 and the rod side chamber 45 by the piston 43. In the piston 43, a flow path 43a is formed between the piston side chamber 44 and the rod side chamber 45 to allow the five senses of the hydraulic oil. With respect to the piston side chamber 44, hydraulic fluid is rapidly supplied by the working fluid supply / discharge device 50, and the lifting cylinder 40 expands and contracts according to the supply / discharge of the hydraulic fluid. Thus, in this embodiment, the lifting cylinder 40 is a single acting fluid pressure cylinder. Instead of this, as the lifting cylinder 40, a double-acting fluid pressure cylinder in which hydraulic oil is rapidly supplied to both the piston side chamber 44 and the rod side chamber 45 may be used.

Thus, each lifting cylinder 40 expands and contracts, and the lifting platform 3 and the boom 4 are lifted by rotating each link arm 2. Instead of this configuration, a guide rail extending in the Z-axis direction may be provided in the front portion of the vehicle body 91 so that the lifting table 3 can be lifted and supported in the Z-axis direction by the guide rail. In this case, each lifting cylinder 40 is interposed between the vehicle body 91 and the platform 3, and expands and changes the height of the platform 3 relative to the vehicle body 91.

The working fluid supply and drain device 50 includes a tank T in which hydraulic fluid is stored, and a hydraulic pump 51 as a hydraulic pump driven by an electric motor (not shown) and capable of supplying hydraulic oil in the tank T to the piston side chamber 44. ), A supply / discharge passage 56 communicating with the piston side chamber 44 of the pair of lifting cylinders 40, an operated check valve 53 interposed in the supply / discharge passage 56, and a supply / discharge passage 56 And a direction change valve 52 as a switch valve for switching the communication between the hydraulic pump 51 and the tank T.

The direction switching valve 52 includes a supply passage 55 for guiding hydraulic oil discharged from the hydraulic pump 51, a discharge passage 57 for returning the hydraulic oil to the tank T, and an operated check valve 53. The operated passage 59 communicating with the pilot pressure chamber of the gas chamber and the supply / discharging passage 56 communicating with the piston side chamber 44 are connected. In the relief passage 58 that connects the supply passage 55 and the discharge passage 57, a relief valve 54 that is opened when the hydraulic pressure of the supply passage 55 exceeds the set pressure is provided.

The direction switching valve 52 is configured to extend the lifting position 52a as an operating position for expanding the lifting cylinder 40, the shrinking position 52b as an operating position for shrinking the lifting cylinder 40, and the lifting cylinder 40. An electromagnetic switching valve having a stop position 52c for stopping. The position of the direction change valve 52 is suitably switched so that the height of the boom 4 with respect to the vehicle body 91 may become a desired height.

When the direction change valve 52 is switched to the extended position 52a, the discharge passage 57 and the operated passage 59 communicate with each other, and the supply / discharge passage 56 and the supply passage 55 communicate with each other. The hydraulic oil discharged from the hydraulic pump 51 flows into the piston side chamber 44 of the pair of lifting cylinders 40 through the supply passage 55 and the supply and discharge passage 56. As a result, the pair of lifting cylinders 40 are synchronously extended, the link arm 2 is rotated upward, and the boom 4 is raised relative to the vehicle body 91 together with the link arm 2.

When the direction change valve 52 is switched to the retracted position 52b, the supply passage 55 and the operated passage 59 communicate with each other, and the supply / discharge passage 56 and the discharge passage 57 communicate with each other. Since the discharge pressure of the hydraulic pump 51 is guided as the pilot pressure to the operated check valve 53 through the operated passage 59, the operated check valve 53 is opened to operate the hydraulic oil of the piston side chamber 44. Is returned to the tank (T) via the supply and drain passage (56), the discharge passage (57). As a result, the pair of lifting cylinders 40 synchronously contract, the link arm 2 is rotated downward, and the boom 4 is lowered with respect to the vehicle body 91 together with the link arm 2.

When the direction change valve 52 is switched to the stop position 52c, the supply passage 55, the discharge passage 57, the operated passage 59, and the supply and discharge passage 56 are each closed. As a result, the hydraulic oil entering and exiting the piston side chamber 44 through the supply / discharge passage 56 is blocked, and the operated check valve 53 is closed. Therefore, the movement of each piston 43 in the pair of lifting cylinders 40 is stopped, and the height of the boom 4 with respect to the vehicle body 91 is maintained. In this way, the boom sprayer 100 can adjust the height of the boom 4 with respect to the vehicle body 91, that is, the height of the boom 4 with respect to the crop of pavement by stretching the lifting cylinder 40.

In the boom sprayer 100 of the said structure, the vibration of the up-down direction of the vehicle body 91 is transmitted to the link arm 2 and the boom 4 via the lifting cylinder 40. In order to suppress this, the boom sprayer 100 further includes the boom damping device 60.

The boom vibration suppressing device 60 is a damping valve for imparting resistance to the accumulator 61 connected to the piston side chamber 44 of the lifting cylinder 40 and the hydraulic oil flowing between the piston side chamber 44 and the accumulator 61. Has 62.

The accumulator 61 has an oil chamber 61a connected to the piston side chamber 44 supporting the link arm 2, and a spring chamber 61b for applying pressure to the oil chamber 61a.

The spring chamber 61b is a gas chamber in which gas, such as pressurized nitrogen, is enclosed, and has given gas pressure to the liquid surface which is an interface with the oil chamber 61a. In addition, you may make it mount and store the free piston which partitions the oil chamber 61a and the spring chamber 61b in the accumulator 61. As shown in FIG. In addition, while storing the free piston which partitions the oil chamber 61a and the spring chamber 61b in the accumulator 61, you may make it contain the spring in the spring chamber 61b. That is, instead of pressurized gas, a spring may be used to apply pressure to the oil chamber 61a.

The characteristic of the accumulator 61 is set by adjusting the gas pressure in the spring chamber 61b, the volume of the accumulator 61, and the like.

The oil chamber 61a is connected to the branch passage 64 branched between the piston side chamber 44 and the operated check valve 53 in the supply / discharge passage 56. That is, the oil chamber 61a and the piston side chamber 44 are connected through the supply-discharge passage 56 and the branch passage 64. A damping valve 62 is provided in the branch passage 64, and an opening and closing valve 63 for opening and closing the branch passage 64 is provided adjacent to the damping valve 62.

The opening / closing valve 63 has a communication position 63a allowing communication between the piston side chamber 44 and the accumulator 61, and a shutoff position 63b for blocking communication between the piston side chamber 44 and the accumulator 61. It has an electronic on-off valve.

Usually, the opening-closing valve 63 will be in the communication position 63a, and the piston side chamber 44 and the accumulator 61 will be in communication. In this state, when the vehicle body 91 vibrates up and down and the lifting cylinder 40 vibrates, the working oil flows between the piston side chamber 44 and the oil chamber 61a of the accumulator 61. The hydraulic oil which flowed into the oil chamber 61a is pushed back to the piston side chamber 44 by the gas pressure of the spring chamber 61b. In this way, a resistance is imparted by the damping valve 62 to the flow of the hydraulic oil which flows between the piston side chamber 44 and the oil chamber 61a. Thereby, damping force is generated and it can suppress that the vibration of the lifting cylinder 40 is transmitted to the boom 4.

When it is not necessary to reduce the vibration of the boom 4, such as when traveling on a road with less vibration or when the boom 4 is stored, the opening / closing valve 63 is shut off by the operator 63b. ) Can be switched.

The oil chamber 61a and the piston side chamber 44 may be directly connected by a passage independent of the supply / discharge passage 56. In this case, the damping valve 62 and the opening / closing valve 63 are provided in the independent passage.

The boom sprayer 100 also includes a controller 70 as a control unit for controlling the direction switching valve 52 and the on / off valve 63. The controller 70 is a microcomputer including a central computing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). In the read-only memory, a control program or the like executed in the central processing unit is stored in advance, and the data in the processing of the central processing unit is stored in the random access memory. The I / O interface is used for input / output of information with a device connected to the controller 70. The controller 70 inputs a signal from the operation panel 71 operated by an operator.

The operation panel 71 is provided with a boom raising switch (not shown) operated when the boom 4 is raised relative to the vehicle body 91 and a boom lowering switch operated when the boom 4 is lowered with respect to the vehicle body 91. do. These switches may be a button type to be turned on or off or may be toggled. In addition, a stop switch for stopping the operation of the boom 4 may be provided separately from the boom up switch and the boom down switch. Or the lever type which operates a raise and a lower of the boom 4 may be sufficient. In the case of the lever type, the controller 70 determines that the up switch is operated when the lever is knocked down to one side, and determines that the down switch is operated when the lever is knocked down to the other side; It is determined that the switch has been turned off. In the controller 70, the control described later is executed based on the signal from the operation panel 71, and the positions of the direction change valve 52 and the open / close valve 63 are switched by the controller 70.

The controller 70 is not limited to the microcomputer, and any configuration may be used as long as it is possible to appropriately switch the positions of the direction switching valve 52 and the opening / closing valve 63 according to the operator's operation. For example, it may be a combination of a relay or an electronic timer. In addition, the operation panel 71 may be integrated in the controller 70.

In the boom sprayer 100 having the above configuration, when the boom 4 is raised relative to the vehicle body 91, an inertial force acts temporarily on the boom 4. For this reason, in order to raise the boom 4 quickly, the lifting cylinder 40 must generate a load that exceeds the inertia force acting on the boom 4 in addition to the load supporting the boom 4 in a stationary state. do. That is, it is necessary to raise the pressure of the piston side chamber 44 of the lifting cylinder 40 by the amount corresponding to the inertia force acting on the boom 4.

Here, in the boom sprayer 100, the piston side chamber 44 and the oil chamber 61a of the accumulator 61 are normally connected. For this reason, even if hydraulic oil is supplied from the hydraulic pump 51 to raise the pressure of the piston side chamber 44, hydraulic fluid flows into the oil chamber 61a of the accumulator 61 which communicates with the piston side chamber 44, and accumulates it. The spring chamber 61b of 61 is contracted. As the spring chamber 61b contracts, the pressure in the piston side chamber 44 gradually increases as the pressure of the accumulator 61 rises. When the pressure of the piston side chamber 44 rises by the minute according to the inertia force acting on the boom 4, the lifting cylinder 40 extends, and the boom 4 rises relative to the vehicle body 91.

In this way, the lifting cylinder 40 does not extend unless the pressure of the accumulator 61 rises. For this reason, there exists a possibility that the boom 4 may not rise quickly even if an operator makes operation to raise the boom 4.

In addition, when lowering the boom 4, the load acting on the lifting cylinder 40 from the boom 4 side temporarily decreases due to inertia as compared with the stationary state. Therefore, when the piston side chamber 44 and the oil chamber 61a of the accumulator 61 communicate with each other, the hydraulic oil in the oil chamber 61a having a higher pressure than the piston side chamber 44 is discharged. For this reason, the lifting cylinder 40 starts to contract after the pressure of the accumulator 61 falls, and as a result, the boom 4 may not be lowered quickly even if an operator makes an operation of lowering the boom 4. There is.

In contrast, in the boom sprayer 100 according to the first embodiment, when the boom up switch or the boom down switch is turned on by an operator, the controller 70 controls the opening / closing valve 63 to control the piston side chamber 44. ) And communication between the oil chamber 61a of the accumulator 61 is blocked. As a result, the hydraulic oil is prevented from flowing into the oil chamber 61a when the boom 4 is raised, and the hydraulic oil is prevented from flowing out of the oil chamber 61a when the boom 4 is lowered. As a result, the lifting and lowering of the boom 4 with respect to the vehicle body 91 can be performed quickly for the operator's operation.

The following describes the processing procedure of the controller 70 executed when the operation of lifting and lowering the boom 4 is performed by an operator. The controller 70 controls the open / close valve 63 and the direction change valve 52 in the order shown in the flowchart of FIG. 3. The flowchart of FIG. 3 shows the process sequence at the time of raising the boom 4.

First, in step S101, the controller 70 detects whether the lift switch is operated from off to on by the operator. The operation panel 71 outputs the signal according to the operation to the controller 70, when a rise switch is operated by an operator.

When it is detected that the upward switch is turned on in the controller 70, in step S102, the controller 70 switches the open / close valve 63 to the shutoff position 63b to form the piston side chamber 44 and the accumulator ( The communication of the oil chamber 61a of 61 is interrupted | blocked. At the same time, the controller 70 switches the direction switching valve 52 to the extended position 52a to communicate the piston side chamber 44 with the hydraulic pump 51.

Communication between the piston side chamber 44 and the accumulator 61 is interrupted, and the piston side chamber 44 and the hydraulic pump 51 communicate with each other, so that the hydraulic oil discharged from the hydraulic pump 51 is lost oil 61a of the accumulator 61. It flows into the piston side chamber 44, without flowing into it. As a result, the elevating cylinder 40 is quickly elongated with respect to the operator's operation, and as a result, the response to the raising operation of the boom 4 can be improved.

Subsequently, in step S103, the controller 70 detects whether the lift switch has been operated from on to off by the operator.

When it is detected in the controller 70 that the upward switch is turned off, in step S104, the controller 70 switches the direction change valve 52 to the stop position 52c, and the piston side chamber 44 and the hydraulic pressure. The communication of the pump 51 is interrupted. Since the supply of hydraulic oil from the hydraulic pump 51 to the piston side chamber 44 stops, and the back flow from the piston side chamber 44 to the hydraulic pump 51 is blocked by the operated check valve 53, the piston side chamber 44 The inside) is filled with a predetermined amount of hydraulic oil.

The pressure in the piston side chamber 44 increases the pressure that balances the weight of the lifting platform 3 and the boom 4 supported by the lifting cylinder 40 from the pressure increased by the amount corresponding to the inertia force, that is, the boom 4. It gradually falls until it becomes the pressure before raising. In addition, even if the pressure in the piston side chamber 44 decreases, the amount of hydraulic oil to be charged does not change, so the amount of extension of the lifting cylinder 40 does not change, and as a result, the height of the boom 4 is maintained.

Here, if the pressure in the piston side chamber 44 allows communication between the piston side chamber 44 and the oil chamber 61a of the accumulator 61 before returning to the pressure before raising the boom 4, the piston rather than the oil chamber 61a Since the pressure in the side chamber 44 is high, the hydraulic oil in the piston side chamber 44 moves to the oil chamber 61a. As a result, there is a possibility that the lifting cylinder 40 temporarily contracts slightly, or the hydraulic oil travels between the piston side chamber 44 and the oil chamber 61a to destabilize the extension amount of the lifting cylinder 40.

Therefore, the predetermined 1st holding time t1 which suppresses switching of the on-off valve 63 from the stop position 52c to the communication position 63a is set. The 1st holding time t1 is set to the time until the pressure in the piston side chamber 44 returns to the pressure before raising the boom 4 after switching the direction change valve 52 to the stop position 52c. do.

In step S105, it is determined whether the 1st holding time t1 set in this way has passed since execution of step S104.

If it is determined that the first holding time t1 has elapsed, the controller 70 switches the open / close valve 63 to the communication position 63a in step S106.

By the above process being performed by the controller 70, the boom 4 is raised to a desired height.

When lowering the boom 4, it differs only in the point which changes the direction change valve 52 to the retracted position 52b instead of the extended position 52a in the said process. For this reason, the description is abbreviate | omitted.

As described above, by blocking the communication between the piston side chamber 44 and the oil chamber 61a while the boom 4 is being raised and lowered, the influence of the inertial force acting on the boom 4 can be reliably removed. As a result, the response of the lifting and lowering of the boom 4 with respect to the operator's operation can be improved.

In addition, communication between the piston side chamber 44 and the oil chamber 61a of the accumulator 61 is permitted after sufficient time has passed for the pressure in the piston side chamber 44 to return to the pressure before raising and lowering the boom 4. . For this reason, after switching the opening / closing valve 63 to the communication position 63a, hydraulic fluid will flow in the piston side chamber 44 and the oil chamber 61a by the pressure difference of the pressure of the piston side chamber 44 and the pressure of the oil chamber 61a. It is suppressed to move between). As a result, the lifting cylinder 40 is prevented from extending or contracting after the lifting and lowering of the boom 4 is stopped.

The direction change valve 52 is not limited to the thing of the form in which a position is switched by an electromagnetic force, The position may be changed manually. In this case, when the operator operates a lever or the like that interlocks with the direction change valve 52 to raise the boom 4, the operator switches to the extended position 52a and when the boom 4 is lowered, it contracts. When switching to the position 52b and stopping the boom 4, it switches to the stop position 52c. The controller 70 detects at which position the direction change valve 52 has been operated by the operator, and controls the opening / closing valve 63 based on the detection result. Specifically, the controller 70 switches the open / close valve 63 to the shutoff position 63b when the direction change valve 52 is operated by the operator to the extended position 52a or the retracted position 52b. And when the directional control valve 52 is operated by the operator from the extended position 52a or the retracted position 52b to the stop position 52c, the controller 70 will open and close after the 1st holding time t1 has passed. The valve 63 is switched to the communication position 63a.

According to the above 1st Embodiment, the effect shown below is exhibited.

In the boom sprayer 100, when an operation of raising and lowering the boom 4 is performed by an operator, the controller 70 switches the open / close valve 63 to the shutoff position 63b and the piston side chamber 44. The communication of the oil chamber 61a of the accumulator 61 is interrupted. Thereby, when raising the boom 4, hydraulic oil is supplied only to the lifting cylinder 40, and hydraulic oil is prevented from flowing into the oil chamber 61a. Moreover, when lowering the boom 4, hydraulic oil flows out only from the lifting cylinder 40, and hydraulic oil is prevented from flowing out from the oil chamber 61a. As a result, the response of the lifting and lowering of the boom 4 with respect to the operator's operation can be improved.

Moreover, in the boom sprayer 100, when the operation which stops the boom 4 by an operator is performed, the controller 70 will switch the direction change valve 52 to the stop position 52c, and will be prescribed | regulated. After 1 hold time t1 has elapsed, the on-off valve 63 is switched to the communication position 63a. Thus, after sufficient time has passed for the pressure in the piston side chamber 44 to return to the pressure before raising and lowering the boom 4, the piston side chamber 44 and the oil chamber 61a of the accumulator 61 are communicated. For this reason, after switching the opening / closing valve 63 to the communication position 63a, hydraulic fluid will flow in the piston side chamber 44 and the oil chamber 61a by the pressure difference of the pressure of the piston side chamber 44 and the pressure of the oil chamber 61a. It is suppressed to move between). As a result, after the lifting and lowering of the boom 4 is stopped, the lifting cylinder 40 is prevented from stretching, and the height of the boom 4 with respect to the vehicle body 91 can be stabilized.

Hereinafter, with reference to FIG. 4, the modification of the boom sprayer 100 which concerns on 1st Embodiment of this invention is demonstrated.

In the said 1st Embodiment, the operation which stops the boom 4 by an operator is performed to switch to the communication position 63a of the switching valve 63, and the direction change valve 52 switches to the stop position 52c. After that, the predetermined first holding time t1 has elapsed. Instead of this, the operation of raising and lowering the boom 4 is performed by the operator to switch the on-off valve 63 to the communication position 63a, and the direction switching valve 52 is the extended position 52a or the retracted position 52b. ), And when the predetermined second holding time t2 has elapsed.

As described above, if the pressure in the piston side chamber 44 allows communication between the piston side chamber 44 and the oil chamber 61a of the accumulator 61 before returning to the pressure before raising the boom 4, the oil chamber 61a Since the pressure of the piston side chamber 44 is higher than the pressure of the piston side chamber 44, the hydraulic oil in the piston side chamber 44 moves to the oil chamber 61a. As a result, there is a possibility that the lifting cylinder 40 temporarily contracts slightly, or the hydraulic oil travels between the piston side chamber 44 and the oil chamber 61a to destabilize the extension amount of the lifting cylinder 40.

Here, the pressure in the piston side chamber 44 becomes higher than the pressure before raising the boom 4 due to the influence of the inertial force acting on the boom 4. This inertial force acts when the boom 4 is accelerating, such as when it rises from a state where the boom 4 is stopped. That is, it does not work when the whole boom 4 rises at a constant speed. For this reason, when some time passes after the boom 4 starts to rise, the inertia force does not act on the whole boom 4, so the pressure in the piston side chamber 44 is increased before the boom 4 is raised. It will return to pressure.

For this reason, in a modification, after switching of the on-off valve 63 to the communication position 63a switches the direction switching valve 52 to the extended position 52a or the retracted position 52b, ie, the open / close valve ( After switching 63) to the cutoff position 63b, the predetermined second holding time t2 elapses.

Below, in the modification, the processing procedure of the controller 70 performed when the operation which raises and lowers the boom 4 by a worker is demonstrated concretely. The controller 70 controls the on-off valve 63 and the direction change valve 52 in the order shown in the flowchart of FIG. 4. The flowchart of FIG. 4 shows the process sequence at the time of raising the boom 4.

Since step S111 and step S112 are the same as step S101 and step S102 in the said 1st Embodiment, the description is abbreviate | omitted.

In step S113, it is determined whether the second holding time t2 has elapsed since step S112 is executed. After switching the direction change valve 52 to the extended position 52a, the 2nd holding time t2 will be in the state which the whole boom 4 raises at a constant speed, and the pressure in the piston side chamber 44 will become the boom 4 ) Is set to a sufficient time until the pressure is returned to the pressure before raising.

If it is determined that the second hold time t2 has elapsed, the controller 70 switches the open / close valve 63 to the communication position 63a in step S114.

In addition, when the lift switch is operated off by the operator before the second holding time t2 elapses, the controller 70 switches the direction switching valve 52 to the stop position 52c, and the piston side chamber 44 The communication of the hydraulic pump 51 is interrupted. However, the switching of the on-off valve 63 to the communication position 63a is not performed until the second holding time t2 has elapsed, regardless of whether the lift switch is turned off or not. That is, although not shown in the flowchart of FIG. 4, when the controller 70 detects that the lift switch is turned off by the operator regardless of whether the second holding time t2 has elapsed, the controller 70 switches the direction. The valve 52 is switched to the stop position 52c to interrupt communication between the piston side chamber 44 and the hydraulic pump 51.

When lowering the boom 4, it differs only in the point which changes the direction change valve 52 to the retracted position 52b instead of the extended position 52a in the said process. For this reason, the description is abbreviate | omitted.

Thus, in the modification, the controller 70 detects the operation which raises and lowers the boom 4 by an operator, switches the open / close valve 63 to the cutoff position 63b, and then predetermined 2nd hold time t2 is set. After passing, the on-off valve 63 is switched to the communication position 63a. That is, the communication between the piston side chamber 44 and the oil chamber 61a of the accumulator 61 is permitted after sufficient time has passed for the pressure in the piston side chamber 44 to return to the pressure before raising and lowering the boom 4. . For this reason, even if the on-off valve 63 is switched to the communication position 63a, the hydraulic oil is caused by the pressure difference between the pressure of the piston side chamber 44 and the pressure of the oil chamber 61a, so that the hydraulic fluid is connected to the piston side chamber 44 and the oil chamber ( Traveling between 61a) is suppressed.

Further, communication between the piston side chamber 44 and the oil chamber 61a is allowed without waiting for an operation for stopping the lifting of the boom 4 by the operator. For this reason, the function of the boom damping apparatus 60 can return quickly, and it can suppress that the vibration of the vehicle body 91 is transmitted to the boom 4. As a result, the lifting operation of the boom 4 can be performed smoothly without being influenced by the inertia force acting on the boom 4 and the vibration of the vehicle body 91.

<2nd embodiment>

With reference to FIG. 5, the boom sprayer 200 which concerns on 2nd Embodiment of this invention is demonstrated. Hereinafter, it demonstrates centering around a different point from the said 1st Embodiment, and attaches | subjects the same code | symbol to the structure same as the boom sprayer 100 of 1st Embodiment, and abbreviate | omits description.

The basic configuration of the boom sprayer 200 is similar to that of the boom sprayer 100 according to the first embodiment. In the boom sprayer 100 according to the first embodiment, while the switching to the communication position 63a of the on / off valve 63 is performed after a predetermined holding time has elapsed, in the boom sprayer 200, The switching to the communication position 63a of the on-off valve 63 differs in that it is performed based on the pressure difference ΔP between the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a of the accumulator 61.

The boom sprayer 200 is installed in the supply / discharge passage 56, is installed in the first pressure sensor 72 and the branch passage 64 to detect the pressure in the piston side chamber 44, and the accumulator 61 is disposed. The second pressure sensor 73 which detects the pressure in the oil chamber 61a, and the differential pressure detection part 74 which detects the difference of the detected value of the 1st pressure sensor 72 and the detected value of the 2nd pressure sensor 73 Equipped. The differential pressure detection unit 74 outputs the detected differential pressure ΔP to the controller 70.

Here, as described above, if the pressure in the piston side chamber 44 allows communication between the piston side chamber 44 and the oil chamber 61a of the accumulator 61 before the pressure is returned to the pressure before raising the boom 4, the loss is lost. Since the pressure in the piston side chamber 44 is higher than the 61a, the hydraulic oil in the piston side chamber 44 moves to the oil chamber 61a. As a result, there is a possibility that the lifting cylinder 40 temporarily contracts slightly, or the hydraulic oil travels between the piston side chamber 44 and the oil chamber 61a to destabilize the extension amount of the lifting cylinder 40.

In other words, when the pressure in the piston side chamber 44 becomes equal to the pressure in the oil chamber 61a, that is, the inertial force does not act on the entire boom 4, so that the pressure in the piston side chamber 44 becomes the boom 4. When the piston side chamber 44 and the oil chamber 61a are allowed to communicate when the pressure is returned to the pressure before raising the), the boom 4 can be smoothly raised and the boom 4 can be stably stopped. have.

For this reason, in the boom sprayer 200, the switching of the on-off valve 63 to the communication position 63a is such that the differential pressure ΔP between the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a is equal to or less than the predetermined threshold α. When the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a become substantially equal.

Hereinafter, in 2nd Embodiment, the processing procedure of the controller 70 performed when the operation which raises and lowers the boom 4 by a worker is demonstrated concretely. The controller 70 controls the on-off valve 63 and the direction change valve 52 in the order shown in the flowchart of FIG. 6. The flowchart of FIG. 6 shows the process sequence at the time of raising the boom 4.

Since step S201 to step S204 are the same as step S101 to step S104 in the said 1st Embodiment, the description is abbreviate | omitted.

In step S205, the controller 70 determines whether or not the pressure difference ΔP between the pressure in the piston side chamber 44 input from the differential pressure detection unit 74 and the pressure in the oil chamber 61a is equal to or less than the predetermined threshold α. The predetermined threshold value α is a value in which the amount of extension of the lifting cylinder 40 is maintained while the hydraulic oil hardly goes between the piston side chamber 44 and the oil chamber 61a even when the piston side chamber 44 and the oil chamber 61a are in communication with each other. Is set.

If it is determined that the differential pressure ΔP is equal to or less than the threshold α, the controller 70 switches the open / close valve 63 to the communication position 63a in step S206.

By the above process being performed by the controller 70, the boom 4 is raised to a desired height.

When lowering the boom 4, it differs only in the point which changes the direction change valve 52 to the retracted position 52b instead of the extended position 52a in the said process. For this reason, the description is abbreviate | omitted.

The pressure difference ΔP between the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a may be determined by a differential pressure sensor that detects the differential pressure before and after the opening / closing valve 63. In addition, the differential pressure detection unit 74 may be integrated into the controller 70.

According to the second embodiment described above, in addition to the effect of the first embodiment, the following effects are obtained.

In the boom sprayer 200, when an operation for stopping the boom 4 is performed by an operator, the controller 70 switches the direction switching valve 52 to the stop position 52c, and then the piston side chamber 44. When the pressure difference ΔP between the pressure in the cylinder and the pressure in the oil chamber 61a becomes equal to or less than the predetermined threshold α, the switching valve 63 is switched to the communication position 63a. Thus, the pressure in the piston side chamber 44 returns to the pressure before raising and lowering the boom 4, becomes equal to the pressure in the oil chamber 61a, and then the oil chamber 61a of the piston side chamber 44 and the accumulator 61 is lost. Is in communication. For this reason, after switching the opening / closing valve 63 to the communication position 63a, due to the pressure difference of the pressure of the piston side chamber 44 and the pressure of the oil chamber 61a, hydraulic fluid is the piston side chamber 44 and the oil chamber ( Traveling between 61a) is surely suppressed.

In addition, as in the first embodiment, the piston side chamber 44 and the oil chamber 61a are not required to wait for the passage of the first predetermined hold time t1 and the pressure difference ΔP is equal to or less than the predetermined threshold α. ) Is immediately communicated. For this reason, the function of the boom damping apparatus 60 returns quickly, and transmission of the vibration of the vehicle body 91 to the boom 4 is suppressed. As a result, after stopping the lifting of the boom 4, the expansion and contraction of the lifting cylinder 40 due to the pressure difference ΔP is suppressed, and the vibration of the vehicle body 91 is suppressed from being transmitted to the boom 4. The height of the boom 4 with respect to the vehicle body 91 can be stabilized.

Hereinafter, with reference to FIG. 7, the modification of the boom sprayer 200 which concerns on 2nd Embodiment of this invention is demonstrated.

In the second embodiment, the switching of the on-off valve 63 to the communication position 63a is performed by an operator to stop the boom 4, and the direction change valve 52 is switched to the stop position 52c. After that, the process is performed based on the pressure difference ΔP. Instead of this, the operation of raising and lowering the boom 4 is performed by the operator to switch the on-off valve 63 to the communication position 63a, and the direction switching valve 52 is the extended position 52a or the retracted position 52b. ), And may be performed based on the pressure difference ΔP.

Below, in the modification, the processing procedure of the controller 70 performed when the operation which raises and lowers the boom 4 by a worker is demonstrated concretely. The controller 70 controls the on-off valve 63 and the direction change valve 52 in the order shown in the flowchart of FIG. 7. The flowchart of FIG. 7 shows the process sequence at the time of raising the boom 4.

Since step S211 and step S212 are the same as step S201 and step S202 in the said 2nd Embodiment, the description is abbreviate | omitted.

In step S213, the controller 70 determines whether the pressure difference ΔP between the pressure in the piston side chamber 44 input from the differential pressure detection unit 74 and the pressure in the oil chamber 61a is equal to or less than the predetermined threshold α.

If it is determined that the differential pressure ΔP is equal to or less than the threshold α, the controller 70 switches the open / close valve 63 to the communication position 63a in step S214.

In addition, when the upward switch is turned off by the operator before the differential pressure ΔP becomes lower than or equal to the threshold α, the controller 70 switches the direction switching valve 52 to the stop position 52c, and the piston side chamber 44 The communication of the hydraulic pump 51 is interrupted. However, the switching of the on-off valve 63 to the communication position 63a is not performed until the differential pressure ΔP becomes equal to or less than the threshold α, regardless of whether the lift switch is turned off or not. That is, although it is not shown in the flowchart of FIG. 7, if the controller 70 detects that the lift switch is OFF-operated by an operator regardless of whether or not the differential pressure ΔP is lower than or equal to the threshold value α, the controller 70 moves in the direction. The switching valve 52 is switched to the stop position 52c to interrupt communication between the piston side chamber 44 and the hydraulic pump 51.

When lowering the boom 4, it differs only in the point which changes the direction change valve 52 to the retracted position 52b instead of the extended position 52a in the said process. For this reason, the description is abbreviate | omitted.

In the said modification, the controller 70 detects the operation which raises and lowers the boom 4 by an operator, switches the opening-closing valve 63 to the interruption position 63b, and the pressure in the piston side chamber 44 is lost. When the pressure difference (DELTA) P of the pressure in 61a becomes below the threshold (alpha), the switching valve 63 is switched to the communication position 63a. Thus, the pressure in the piston side chamber 44 returns to the pressure before raising and lowering the boom 4, becomes equal to the pressure in the oil chamber 61a, and then the oil chamber 61a of the piston side chamber 44 and the accumulator 61 is lost. Is in communication. Therefore, even if the on-off valve 63 is switched to the communication position 63a, the hydraulic oil is caused by the pressure difference between the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a. It is suppressed to move between).

Further, communication between the piston side chamber 44 and the oil chamber 61a is allowed without waiting for an operation for stopping the lifting of the boom 4 by the operator. For this reason, the function of the boom damping apparatus 60 can return quickly, and it can suppress that the vibration of the vehicle body 91 is transmitted to the boom 4. As a result, the lifting operation of the boom 4 can be performed smoothly without being influenced by the inertia force acting on the boom 4 and the vibration of the vehicle body 91.

EMBODIMENT OF THE INVENTION Hereinafter, the structure, operation | movement, and effect of embodiment of this invention are collectively demonstrated.

The boom lifting device includes a lifting platform 3 which can lift up and down the vehicle body 91, a boom 4 having one end supported by the lifting platform 3, the other end being provided as a free end, and spraying the chemical liquid, and the vehicle body 91. An elevating cylinder 40 interposed between the elevating platform and the elevating platform 3, a working fluid supplying and discharging device 50 for supplying hydraulic oil to the elevating cylinder 40 and elevating the boom 4 with respect to the vehicle body 91; The accumulator 61 connected to the lifting cylinder 40 and storing the pressurized hydraulic oil, the opening / closing valve 63 for opening and closing the passage communicating the lifting cylinder 40 with the accumulator 61, and according to the operator's operation The controller 70 which controls the opening / closing valve 63 is provided, The controller 70 is characterized by closing the opening / closing valve 63 when it detects the operation which raises and lowers the boom 4 by an operator. .

In this structure, when the operation which raises and lowers the boom 4 by an operator is performed, the controller 70 will switch the opening-closing valve 63 to the interruption position 63b, and the piston side chamber 44 and the accumulator 61 will be made. The communication of the loss (61a) of the cut off. As a result, when raising the boom 4, the hydraulic oil is supplied only to the lifting cylinder 40, and the hydraulic oil is prevented from flowing into the accumulator 61. Moreover, when lowering the boom 4, hydraulic oil flows out only from the lifting cylinder 40, and hydraulic oil is prevented from flowing out from the oil chamber 61a. As a result, the response of the lifting and lowering of the boom 4 with respect to the operator's operation can be improved.

In addition, the working fluid supply and drain device 50 includes a hydraulic pump 51 for supplying hydraulic oil to the lifting cylinder 40, a tank T for introducing hydraulic oil discharged from the lifting cylinder 40, and a lifting cylinder 40. ) And a direction change valve 52 for switching the connection state of the hydraulic pump 51 and the connection state of the lifting cylinder 40 and the tank T, respectively, and the direction switching valve 52 opens the lifting cylinder 40. It has the extended position 52a and the contraction position 52b which operate, and the stop position 52c which stops the lifting cylinder 40, and the controller 70 detects the operation which raises and lowers the boom 4 by an operator. In one case, the closing valve 63 is closed and the direction switching valve 52 is switched to the extended position 52a or the retracted position 52b.

In this structure, when the operation which raises and lowers the boom 4 by an operator is performed, the controller 70 will switch the opening-closing valve 63 to the interruption position 63b, and the piston side chamber 44 and the accumulator 61 will be made. The communication of the loss (61a) of the cut off. In addition, the controller 70 switches the direction switching valve 52 to the extended position 52a or the retracted position 52b. As a result, when raising the boom 4, the hydraulic oil is supplied only to the lifting cylinder 40, and the hydraulic oil is prevented from flowing into the accumulator 61. In addition, when lowering the boom 4, hydraulic oil flows out only from the lifting cylinder 40, and it prevents that hydraulic oil flows out from the oil chamber 61a. As a result, the response of the lifting and lowering of the boom 4 with respect to the operator's operation can be improved.

In addition, when the controller 70 detects an operation to stop the lifting and lowering of the boom 4 by the operator, the controller 70 opens the on / off valve 63 after the first predetermined holding time t1 has elapsed after the detection. It is done.

In this configuration, when an operation to stop the boom 4 is performed by an operator, the controller 70 switches the direction change valve 52 to the stop position 52c, and the predetermined first holding time t1 has elapsed. After that, the on-off valve 63 is switched to the communication position 63a. Thus, after sufficient time has passed for the pressure in the piston side chamber 44 to return to the pressure before raising and lowering the boom 4, the piston side chamber 44 and the oil chamber 61a of the accumulator 61 will communicate. For this reason, after switching the opening / closing valve 63 to the communication position 63a, due to the pressure difference of the pressure of the piston side chamber 44 and the pressure of the oil chamber 61a, hydraulic fluid is the piston side chamber 44 and the oil chamber ( Traveling between 61a) is suppressed. As a result, after the lifting and lowering of the boom 4 is stopped, the lifting cylinder 40 is prevented from stretching, and the height of the boom 4 with respect to the vehicle body 91 can be stabilized.

Further, the boom lifting device further includes a differential pressure detection unit 74 that detects a pressure difference between the pressure of the lifting cylinder 40 and the pressure of the accumulator 61, and the controller 70 includes a boom 4 by an operator. When the operation for stopping the lifting of the vehicle is detected, the on-off valve 63 is opened when the pressure difference detected by the differential pressure detection unit 74 becomes equal to or less than the predetermined threshold α after the detection.

In this configuration, when an operation to stop the boom 4 is performed by the operator, the controller 70 switches the direction switching valve 52 to the stop position 52c, and then the pressure in the piston side chamber 44 When the pressure difference ΔP of the pressure in the oil chamber 61a becomes equal to or less than the predetermined threshold α, the on-off valve 63 is switched to the communication position 63a. Thus, the pressure in the piston side chamber 44 returns to the pressure before raising and lowering the boom 4, becomes equal to the pressure in the oil chamber 61a, and the oil chamber 61a of the piston side chamber 44 and the accumulator 61 is performed. Is in communication. For this reason, after switching the opening / closing valve 63 to the communication position 63a, due to the pressure difference of the pressure of the piston side chamber 44 and the pressure of the oil chamber 61a, hydraulic fluid is the piston side chamber 44 and the oil chamber ( Traveling between 61a) is surely suppressed. As a result, after the lifting and lowering of the boom 4 is stopped, the lifting cylinder 40 is prevented from expanding and contracting, so that the height of the boom 4 with respect to the vehicle body 91 can be stabilized.

In addition, the controller 70 detects an operation of elevating the boom 4 by the operator, closes the open / close valve 63, and then opens the open / close valve 63 after the predetermined second holding time t2 has elapsed. It is characterized by.

In this structure, the controller 70 detects operation which raises and lowers the boom 4 by an operator regardless of the operation which stops the boom 4, and moves the on-off valve 63 to the shutoff position 63b. After switching, after the predetermined 2nd hold time t2 has passed, the switching valve 63 is switched to the communication position 63a. That is, the communication between the piston side chamber 44 and the oil chamber 61a of the accumulator 61 is permitted after sufficient time has passed for the pressure in the piston side chamber 44 to return to the pressure before raising and lowering the boom 4. . For this reason, even if the on-off valve 63 is switched to the communication position 63a, the hydraulic oil is caused by the pressure difference between the pressure of the piston side chamber 44 and the pressure of the oil chamber 61a, so that the hydraulic fluid is connected to the piston side chamber 44 and the oil chamber ( Traveling between 61a) is suppressed. As a result, the lifting operation of the boom 4 can be performed smoothly without being influenced by the inertial force acting on the boom 4.

Further, the boom lifting device further includes a differential pressure detection unit 74 that detects a pressure difference between the pressure of the lifting cylinder 40 and the pressure of the accumulator 61, and the controller 70 includes a boom 4 by an operator. It is characterized by opening and closing the valve 63 when the operation for raising and lowering the pressure is closed and the closing valve 63 is closed and the pressure difference detected by the differential pressure detecting unit 74 becomes equal to or less than the predetermined threshold α.

In this structure, the controller 70 detects operation which raises and lowers the boom 4 by an operator regardless of the operation which stops the boom 4, and moves the on-off valve 63 to the shutoff position 63b. After switching, when the pressure difference ΔP between the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a becomes equal to or less than the threshold α, the on-off valve 63 is switched to the communication position 63a. Thus, the pressure in the piston side chamber 44 returns to the pressure before raising and lowering the boom 4, becomes equal to the pressure in the oil chamber 61a, and the oil chamber 61a of the piston side chamber 44 and the accumulator 61 is performed. Is in communication. Therefore, even if the on-off valve 63 is switched to the communication position 63a, the hydraulic oil is caused by the pressure difference between the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a. Traveling between 61a) is suppressed. As a result, the lifting operation of the boom 4 can be performed smoothly without being influenced by the inertial force acting on the boom 4.

The boom sprayers 100 and 200 are provided with the said boom lifting apparatus.

In this configuration, by providing the boom lifting device, the lifting and lowering of the boom 4 with respect to the vehicle body 91 can be quickly performed for the operator's operation.

As mentioned above, although embodiment of this invention was described, the said embodiment showed only a part of application example of this invention, and it is not the meaning which limits the technical scope of this invention to the specific structure of the said embodiment.

For example, different control may be employed in the case of raising the boom 4 and in the case of lowering the boom 4. For example, when raising the boom 4, after the predetermined time has elapsed after the stop operation is performed, the switching valve 63 is switched to the communication position 63a, and when the boom 4 is lowered, Regardless of the stop operation, the on-off valve 63 may be switched to the communication position 63a after a predetermined time has elapsed since the lowering operation was started. In addition, when raising the boom 4, the on-off valve 63 is switched to the communication position 63a on the basis of the pressure difference ΔP between the pressure in the piston side chamber 44 and the pressure in the oil chamber 61a. When lowering 4), on / off valve 63 may be switched to communication position 63a based on the elapsed time.

This application claims priority based on Japanese Patent Application No. 2015-144245 for which it applied to Japan Patent Office on July 21, 2015, and all the content of this application is integrated in this specification by reference.

Claims (7)

The elevating member which can go up and down about a vehicle body,
A boom whose one end is supported by the elevating member and whose other end is provided as a free end to spray liquid;
A hydraulic cylinder interposed between the vehicle body and the elevating member;
A working fluid dispensing device for dispensing a working fluid with respect to the hydraulic cylinder to raise and lower the boom with respect to the vehicle body;
An accumulator connected to the hydraulic cylinder and storing a pressurized working fluid;
An on / off valve for opening and closing a passage communicating the hydraulic cylinder and the accumulator;
It is provided with a control unit for controlling the opening and closing valve in accordance with the operator's operation,
When the control unit detects an operation of raising or lowering the boom by an operator, when the operation detects an operation of closing the opening / closing valve and stopping the raising or lowering of the boom by the operator, the predetermined first holding time after detection The boom lifting device which opens the said on-off valve after this time passes. The elevating member which can go up and down about a vehicle body,
A boom whose one end is supported by the elevating member and whose other end is provided as a free end to spray liquid;
A hydraulic cylinder interposed between the vehicle body and the elevating member;
A working fluid dispensing device for dispensing a working fluid with respect to the hydraulic cylinder, and elevating the boom with respect to the vehicle body;
An accumulator connected to the hydraulic cylinder and storing a pressurized working fluid;
An on / off valve for opening and closing a passage communicating the hydraulic cylinder and the accumulator;
A control unit for controlling the opening / closing valve according to an operator's operation;
And a differential pressure detector for detecting a pressure difference between the pressure of the hydraulic cylinder and the pressure of the accumulator,
When the control unit detects an operation of elevating the boom by the operator, when the operation of closing the open / close valve and detecting an operation of stopping the raising or lowering of the boom by the operator, the control unit detects the operation of detecting the operation of the boom. And the pressure-opening valve is opened when the pressure difference is less than or equal to a predetermined threshold. The elevating member which can go up and down about a vehicle body,
A boom whose one end is supported by the elevating member and whose other end is provided as a free end to spray liquid;
A hydraulic cylinder interposed between the vehicle body and the elevating member;
A working fluid dispensing device for dispensing a working fluid with respect to the hydraulic cylinder, and elevating the boom with respect to the vehicle body;
An accumulator connected to the hydraulic cylinder and storing a pressurized working fluid;
An on / off valve for opening and closing a passage communicating the hydraulic cylinder and the accumulator;
It is provided with a control unit for controlling the opening and closing valve in accordance with the operator's operation,
When the control unit detects an operation of elevating the boom by an operator, the control unit closes the open / close valve, detects an operation of raising or lowering the boom by an operator, closes the open / close valve, and then holds a predetermined second hold. The boom lifting device which opens the said on-off valve after time passes. The elevating member which can go up and down about a vehicle body,
A boom whose one end is supported by the elevating member and whose other end is provided as a free end to spray liquid;
A hydraulic cylinder interposed between the vehicle body and the elevating member;
A working fluid dispensing device for dispensing a working fluid with respect to the hydraulic cylinder to raise and lower the boom with respect to the vehicle body;
An accumulator connected to the hydraulic cylinder and storing a pressurized working fluid;
An on / off valve for opening and closing a passage communicating the hydraulic cylinder and the accumulator;
A control unit for controlling the opening / closing valve according to an operator's operation;
And a differential pressure detector for detecting a pressure difference between the pressure of the hydraulic cylinder and the pressure of the accumulator,
When the control unit detects an operation of elevating the boom by an operator, the control unit closes the open / close valve, detects an operation of raising or lowering the boom by an operator, closes the open / close valve, and then detects it by the differential pressure detection unit. The opening and closing valve is opened when the said pressure difference becomes below a predetermined threshold. The method according to any one of claims 1 to 4,
The working fluid supply device,
A hydraulic pump for supplying a working fluid to the hydraulic cylinder;
A tank into which a working fluid discharged from the hydraulic cylinder is induced;
It has a switching valve which switches the connection state of the said hydraulic cylinder and the said hydraulic pump, and the connection state of the said hydraulic cylinder and the said tank,
The switching valve has an operating position for operating the hydraulic cylinder and a stop position for stopping the hydraulic cylinder,
And the control unit closes the open / close valve and switches the selector valve to the operating position when detecting an operation of elevating the boom by an operator. The boom sprayer provided with the boom lifting apparatus in any one of Claims 1-4. delete

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