JP2015149976A - Spraying apparatus and boom vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boom vibration control device in which a working fluid is filled in a fluid pressure chamber of the confined side of a fluid pressure cylinder.SOLUTION: A boom vibration control device 7 includes: a fluid pressure cylinder 71 connected with a work vehicle 1 and a boom 6; first accumulator 77 for pressurizing one chamber 75 of the fluid pressure cylinder 71; a second accumulator 78 for pressurizing the other chamber 76 of the fluid pressure cylinder 71; a switching valve 94 for switching between a supply position and a discharge position to supply and discharge a working fluid to one chamber 75; an operation check valve 92 for permitting only a flow from the switching valve 94 to the chamber 75 when the switching valve 94 is in the supply position, and permitting only the flow from one chamber 75 to the switching valve 94 when the switching valve 94 is in the discharge position; an on-off valve 84 for opening and closing a connecting passage 83 to connect a pilot passage 97 with the other chamber 76; and a relief valve 86 for maintaining the working fluid pressure of the connecting passage 83 in a setting pressure. The switching valve 94 is switched to the discharge position to open the on-off valve 84, and thereby the working fluid of the connecting passage 83 maintained in the setting pressure is supplied to the other chamber 76.

Description

  The present invention relates to a spraying device and a boom damping device.

  Patent Document 1 discloses a boom sprayer that sprays a control liquid. The boom sprayer includes a boom support member provided at a front portion of the work vehicle, and left and right booms that are cantilevered by the boom support member and extend in the left-right direction of the vehicle body. Further, the boom support member can be rotated in the roll direction of the vehicle body, and the boom sprayer controls a rolling posture, which is an inclined posture of the boom to the left and right, by a horizontal cylinder.

JP 2005-13935 A

  The horizontal cylinder is, for example, a hydraulic cylinder in which a cylinder tube is connected to a front portion of a work vehicle and a piston rod is connected to a boom support member. A supply / exhaust passage for supplying and discharging hydraulic oil is connected to one chamber of the hydraulic cylinder so that the boom is held horizontally.

  In the above hydraulic cylinder, when the hydraulic oil sealed in the other chamber where hydraulic fluid is not supplied or discharged leaks due to deterioration of the seal over time or the like, the pressure in the other chamber when the boom is held horizontally decreases. This may reduce the centering force of the hydraulic cylinder and make it difficult to hold the boom horizontally.

  The present invention has been made in view of such a technical problem, and provides a spraying device and a boom damping device capable of replenishing a working fluid in a fluid pressure chamber on a sealed side of a fluid pressure cylinder. For the purpose.

  The present invention is a boom damping device that suppresses vibration of a boom that can be rotated in the roll direction of a work vehicle, and is connected to the work vehicle and the boom, and the boom rotates in the roll direction of the work vehicle. A fluid pressure cylinder that expands and contracts in conjunction with each other, pressurizes one chamber of the fluid pressure cylinder, pressurizes the first pressure accumulator through which the working fluid enters and exits as the fluid pressure cylinder expands and contracts, and the other chamber of the fluid pressure cylinder In addition, it is possible to switch between the second pressure accumulator through which the working fluid enters and exits as the fluid pressure cylinder expands and contracts, the supply position for supplying the working fluid to the one chamber, and the discharge position for discharging the working fluid from the one chamber. A switching valve and a supply / exhaust passage connecting the switching valve and the one chamber. When the switching valve is in the supply position, only the flow of the working fluid from the switching valve to the one chamber is allowed. Off when in the discharge position An operating check valve that allows the flow of working fluid from one chamber to the switching valve and the connection passage that connects the pilot passage and the other chamber can be opened and closed using the working fluid pressure supplied from the valve via the pilot passage as the pilot pressure. A relief valve that is interposed in a relief passage that branches from between the pilot passage and the on-off valve in the connection passage, and that maintains the working fluid pressure in the connection passage at a set pressure when the switching valve is in the discharge position; And switching the switching valve to the discharge position and opening the on-off valve to supply the working fluid in the connection passage maintained at the set pressure to the other chamber.

  According to the present invention, the working fluid in the connection passage maintained at the set pressure can be supplied to the other chamber by switching the switching valve to the discharge position and opening the on-off valve. Even if the amount of oil in the fluid pressure chamber leaks and decreases, the working fluid can be easily replenished.

It is a top view of the working vehicle carrying the spraying device which concerns on embodiment of this invention. It is a side view of a work vehicle carrying a spraying device concerning an embodiment of the present invention. It is a perspective view of the spreading device concerning an embodiment of the present invention. It is a block diagram of the boom damping device which concerns on embodiment of this invention. It is a perspective view which shows an example of a fixing jig. It is a perspective view which shows an example of a fixing jig.

  Embodiments of the present invention will be described with reference to the drawings.

  First, the first embodiment will be described.

  For convenience of explanation, three axes of X, Y, and Z orthogonal to each other are set on the attached drawings. The X-axis is an axis extending in the vehicle front-rear direction (substantially horizontal vertical direction), the Y-axis is an axis extending in the left-right direction (substantially horizontal horizontal direction) of the vehicle, and the Z-axis is the vertical direction (substantially vertical direction) of the vehicle. It is the axis | shaft extended in. Further, the rotation direction around the X axis is referred to as the roll direction, and the rotation direction around the Z axis is referred to as the yaw direction.

  FIG. 1 is a plan view of a work vehicle 1 equipped with a spraying device 100 according to this embodiment. FIG. 2 is a side view of the work vehicle 1 on which the spraying device 100 according to this embodiment is mounted, and shows a state where the work vehicle 1 of FIG. 1 is viewed from the Y-axis direction. FIG. 3 is a perspective view of the spraying device 100 mounted on the work vehicle 1.

  The spraying device 100 is mounted on the front side of a work vehicle 1 such as a tractor that travels in a farm field, and is a device for agriculture that sprays a control solution (pesticidal chemical) from the work vehicle 1.

  The spreading device 100 includes a link arm 2 attached to the front of the work vehicle 1, a lift cylinder 3 that lifts and lowers the link arm 2, and a lift 4 that is supported by the link arm 2 so as to be lifted and lowered relative to the work vehicle 1. A roll base 5 that is rotatably supported in the roll direction with respect to the lift base 4 and a boom 6 that extends from the roll base 5 in the left-right direction (Y-axis direction) of the work vehicle 1.

  The link arm 2 is a link mechanism including a pair of upper links 21 and lower links 22 provided on the left and right sides of the work vehicle 1. The upper link 21 and the lower link 22 extend in parallel to each other, and are arranged to form a parallelogram when viewed from the side (FIG. 2).

  The upper link 21 is pivotally connected to the work vehicle 1 via a pin 23 at the base end, and is pivotally connected to the elevator 4 via a pin 24 at the distal end. The lower link 22 is pivotally connected to the work vehicle 1 via a pin 25 at the base end, and is pivotally connected to the lifting platform 4 at a distal end via a pin 26.

  The link arm 2 supports the lifting platform 4 to be movable up and down. Instead, a guide rail extending in the Z-axis direction is provided at the front portion of the work vehicle 1 and the lifting platform 4 is supported by the guide rail to be movable up and down. May be.

  A pair of elevating cylinders 3 is provided on the left and right of the work vehicle 1. Each elevating cylinder 3 is interposed between the work vehicle 1 and the upper link 21 and expands and contracts according to the supply and discharge of hydraulic oil. When the lifting cylinder 3 is extended, the link arm 2 is rotated upward, and the lifting platform 4 and the boom 6 are raised. When the lifting cylinder 3 is contracted, the link arm 2 is rotated downward, and the lifting platform 4 and the boom 6 are lowered.

  The lifting platform 4 is connected to the tips of the upper link 21 and the lower link 22 via pins 24 and 26, and moves up and down in accordance with the rising and lowering of the link arm 2.

  The roll table 5 is provided in front of the lift table 4 and is rotatably supported by the lift table 4 via a support shaft 51 (FIG. 3). The roll base 5 is rotatable in the roll direction with respect to the lifting / lowering base 4 about the support shaft 51 and constitutes a central boom that supports the left and right booms 61 and 62. The support shaft 51 is a cylindrical pin, but is not limited thereto, and a spherical bearing or the like may be used.

  The boom 6 has a right boom 61 that can be deployed in the right direction of the work vehicle 1 and a left boom 62 that can be deployed in the left direction of the work vehicle 1. Each of the right boom 61 and the left boom 62 is cantilevered by the roll base 5. That is, each of the right boom 61 and the left boom 62 is cantilevered by the roll base 5 so that the base end portion can rotate in the yaw direction about a rotation shaft (not shown), and the distal end portion becomes a free end. .

  The right boom 61 includes a proximal end frame 61A having a proximal end portion, and a distal end side frame 61B having a distal end portion that is supported on the distal end side of the proximal end side frame 61A so as to be extendable and contractable. The left boom 62 includes a proximal side frame 62A having a proximal end portion, and a distal end side frame 62B having a distal end portion that is supported by the distal end side of the proximal end side frame 62A so as to be extendable and contractable (FIG. 1).

  A nozzle (not shown) for spraying the control liquid is attached to the boom 6. During the operation of the spraying device 100, the control liquid is sprayed from the nozzles of the boom 6 of the spraying device 100 while the work vehicle 1 travels in the field.

  The right boom 61 and the left boom 62 extend in the horizontal direction of the work vehicle 1 when in the unfolded state shown in FIG. The case where the boom 6 is in the deployed state is referred to as the boom 6 being in the working position. When the boom 6 is retracted, the distal end side frames 61B and 62B are slid toward the proximal end side frames 61A and 62A to contract the boom 6, and then the boom 6 is moved rearward around a rotating shaft (not shown). Rotate. Thereby, the boom 6 is folded so as to extend in the front-rear direction along the side of the work vehicle 1.

  The spraying device 100 further includes a boom damping device 7 that is provided between the lifting platform 4 and the roll platform 5 and suppresses vibration of the boom 6 in the roll direction.

  FIG. 4 is a configuration diagram of the boom damping device 7 in the present embodiment. In the following description, the right rotation direction around the X axis when the work vehicle 1 is viewed from the driver is referred to as the right roll direction, and the left rotation direction is referred to as the left roll direction.

  The boom damping device 7 includes one hydraulic cylinder 71 that expands and contracts in conjunction with the boom 6 rotating in the left-right roll direction.

  A hydraulic cylinder 71 as a fluid pressure cylinder has a cylinder tube 72 in which hydraulic oil is sealed, and a piston rod 74 connected to both ends of a piston 73 slidably inserted into the cylinder tube 72. The inside of the cylinder tube 72 is partitioned by a piston 73 into a first chamber 75 as one chamber disposed above and a second chamber 76 as the other chamber disposed below.

  The hydraulic cylinder 71 uses hydraulic fluid as the hydraulic fluid, but hydraulic fluid such as a water-soluble alternative fluid or gas may be used instead of hydraulic fluid.

  The cylinder tube 72 is rotatably connected to the lifting platform 4. A lower end portion of the piston rod 74 is rotatably connected to the roll base 5. That is, the cylinder tube 72 is connected to the work vehicle 1 through the lifting platform 4, and the piston rod 74 is connected to the boom 6 through the roll table 5. Thereby, when the boom 6 rotates in the roll direction, the hydraulic cylinder 71 expands and contracts.

  In addition, not only the structure mentioned above but the structure which the upper end part of the piston rod 74 is connected with the work vehicle 1 via the raising / lowering stand 4 and the cylinder tube 72 is connected with the boom 6 via the roll stand 5 is good.

  The boom damping device 7 further includes a first accumulator 77 as a first accumulator that pressurizes the first chamber 75 of the hydraulic cylinder 71 and a second accumulator as a second accumulator that pressurizes the second chamber 76 of the hydraulic cylinder 71. The accumulator 78, the first passage 79 connecting the first accumulator 77 and the first chamber 75, the second passage 80 connecting the second accumulator 78 and the second chamber 76, and the operation passing through the first passage 79. A first damping valve 81 that imparts resistance to the flow of oil and a second damping valve 82 that imparts resistance to the flow of hydraulic oil passing through the second passage 80 are provided.

  The first accumulator 77 has an oil chamber 77A that communicates with the first passage 79, and a pressure accumulation chamber 77B that stores compressed gas that pressurizes the oil chamber 77A. When the boom 6 rotates in the roll direction, the hydraulic cylinder 71 expands and contracts and hydraulic oil enters and exits the first accumulator 77 through the first passage 79.

  The second accumulator 78 has an oil chamber 78A communicating with the second passage 80, and a pressure accumulating chamber 78B that stores compressed gas that pressurizes the oil chamber 78A. When the boom 6 rotates in the roll direction, the hydraulic cylinder 71 expands and contracts, and the hydraulic oil enters and exits the second accumulator 78 through the second passage 80.

  When the hydraulic cylinder 71 is retracted so that the boom 6 rotates in the left roll direction, the contracting hydraulic fluid in the first chamber 75 flows into the first accumulator 77 and the hydraulic fluid in the second accumulator 78 is expanded. Flow into.

  On the contrary, when the hydraulic cylinder 71 is rotated so that the boom 6 rotates in the right roll direction, the hydraulic oil from the first accumulator 77 flows into the first chamber 75 that expands, and the hydraulic fluid in the second chamber 76 that contracts flows. It flows into the second accumulator 78.

  Thus, the same amount of hydraulic fluid is supplied to and discharged from the first accumulator 77 and the second accumulator 78 as the boom 6 rotates in the right roll direction and the left roll direction. As a result, a pressure difference is generated between the pressure accumulation chamber 77B of the first accumulator 77 and the pressure accumulation chamber 78B of the second accumulator 78. The boom 6 is held at a position where the biasing force biased in the right roll direction by the gas pressure of the first accumulator 77 and the biasing force biased in the left roll direction by the gas pressure of the second accumulator 78 are balanced. The

  The hydraulic cylinder 71 is a double rod type in which the piston rod 74 projects from both ends of the cylinder tube 72. As a result, when the hydraulic cylinder 71 expands and contracts, the flow rate of the hydraulic oil that moves through the first passage 79 becomes equal to the flow rate of the hydraulic oil that moves through the second passage 80, and the change in the gas pressure of the first accumulator 77. And the change in the gas pressure of the second accumulator 78 are equal to each other.

  The first damping valve 81 generates a damping force that suppresses the boom 6 from vibrating in the roll direction by applying resistance to the hydraulic oil passing through the first passage 79 as the hydraulic cylinder 71 expands and contracts.

  The second damping valve 82 generates a damping force that suppresses the boom 6 from vibrating in the roll direction by applying resistance to the hydraulic oil that passes through the second passage 80 as the hydraulic cylinder 71 expands and contracts.

  That is, the first damping valve 81 and the second damping valve 82 function as a roll damper that suppresses the boom 6 from vibrating in the roll direction. The first damping valve 81 and the second damping valve 82 may be fixed throttles, or may be variable throttles whose opening areas increase as the flow rate of the passing hydraulic fluid increases. Further, instead of the first damping valve 81 and the second damping valve 82, a fixed throttle such as an orifice may be interposed so that the throttle channel area or throttle channel length can be adjusted manually.

  The boom damping device 7 further includes a hydraulic oil supply / discharge mechanism 90 that supplies and discharges hydraulic oil to and from the hydraulic cylinder 71. The hydraulic oil supply / discharge mechanism 90 extends and contracts the hydraulic cylinder 71 by supplying and discharging hydraulic oil to and from the hydraulic cylinder 71, and adjusts the roll angle of the boom 6 so that the boom 6 is held in the horizontal direction.

  The hydraulic oil supply / discharge mechanism 90 includes a supply / discharge passage 91 communicating with the first chamber 75 of the hydraulic cylinder 71, an operation check valve 92 interposed in the supply / discharge passage 91, a hydraulic pump 93 and a tank for the supply / discharge passage 91. And a direction switching valve 94 for switching communication with T.

  The direction switching valve 94 includes a supply passage 95 that guides hydraulic oil discharged from the hydraulic pump 93, a discharge passage 96 that returns the hydraulic oil to the tank T, and a pilot passage that communicates with the pilot pressure chamber of the operation check valve 92. An operation passage 97 and a supply / discharge passage 91 communicating with the first chamber 75 are connected. The relief passage 98 that connects the supply passage 95 and the discharge passage 96 is provided with a relief valve 99 that opens when the hydraulic pressure in the supply passage 95 exceeds a set pressure.

  The hydraulic oil supply / discharge mechanism 90 further includes a connection passage 83 that connects the operation passage 97 and the second chamber 76, a needle valve 84 that can open and close the connection passage 83, and an operation passage 97 in the connection passage 83. A relief passage 85 that branches from the needle valve 84 and communicates with the tank T, and a relief valve 86 that opens when the pressure in the connection passage 83 and the relief passage 85 exceeds a predetermined set pressure. .

  The connection passage 83 may be directly connected to the second chamber 76, or may be connected to the second chamber 76 side from the second damping valve 82 of the second passage 80. Further, the supply / discharge passage 91 may be directly connected to the first chamber 75 or may be connected to the first chamber 75 side of the first passage 79 from the first damping valve 81.

  The needle valve 84 is a valve that opens and closes the connection passage 83 by the operation of the driver, and is opened only when hydraulic oil is replenished to the second chamber 76, which will be described later, and is always kept closed.

  The set pressure of the relief valve 86 is set to the pressure of the hydraulic oil sealed in the second chamber 76 when the boom damping device 7 is manufactured. The set pressure of the relief valve 99 is set higher than the set pressure of the relief valve 86.

  Here, the centering operation for switching the direction switching valve 94 to hold the boom 6 in the horizontal direction will be described.

  The direction switching valve 94 has a left roll position a, a right roll position b, and a neutral position c, and is switched to any position so that the boom 6 is held in the horizontal direction.

  When the direction switching valve 94 is switched to the left roll position a, the supply passage 95 and the operation passage 97 are communicated with each other, and the supply / discharge passage 91 and the discharge passage 96 are communicated with each other. Since the discharge pressure of the hydraulic pump 93 is guided as a pilot pressure to the operation check valve 92 via the operation passage 97, the operation check valve 92 is opened, and the hydraulic oil in the first chamber 75 is supplied to the supply / discharge passage 91, the discharge passage. 96 is returned to tank T. As a result, the piston 73 of the hydraulic cylinder 71 moves upward in FIG. 4, and the boom 6 rotates in the left roll direction. Since the needle valve 84 is closed, the hydraulic oil supplied from the operating passage 97 to the connection passage 83 is returned to the tank T by opening the relief valve 86.

  When the direction switching valve 94 is switched to the right roll position b, the discharge passage 96 and the operation passage 97 communicate with each other, and the supply / discharge passage 91 and the supply passage 95 communicate with each other. The hydraulic oil discharged from the hydraulic pump 93 flows into the first chamber 75 through the supply passage 95 and the supply / discharge passage 91. As a result, the piston 73 of the hydraulic cylinder 71 moves downward in FIG. 4, and the boom 6 rotates in the right roll direction.

  When the direction switching valve 94 is switched to the neutral position c, the supply passage 95, the discharge passage 96, the operate passage 97, and the supply / discharge passage 91 communicate with each other, and the hydraulic oil is returned to the tank T. As a result, the operation check valve 92 is closed and the hydraulic oil entering and exiting the first chamber 75 through the supply / discharge passage 91 is shut off. Therefore, the movement of the piston 73 in the hydraulic cylinder 71 is stopped, and the rotation of the boom 6 is stopped.

  Based on a detection signal transmitted from a sensor (not shown) or the like that detects the tilt angle of the boom 6, a controller (not shown) controls the solenoid of the direction switching valve 94 so that the boom 6 is held in the horizontal direction. Drive. Thereby, the boom 6 rotates in the left-right roll direction, the roll angle of the boom 6 is adjusted, and the boom 6 can always be kept horizontal regardless of the posture change of the work vehicle 1.

  The work vehicle 1 sprays the control liquid from the nozzles of the boom 6 of the spraying device 100 while traveling in the field during work. At this time, the left and right booms 61 and 62 are centered at positions where the gas pressures in the accumulator chambers 77B and 78B of the first accumulator 77 and the second accumulator 78 are balanced according to the stroke of the hydraulic cylinder 71.

  For example, when the work vehicle 1 travels over the unevenness of the field and the posture of the work vehicle 1 changes in the roll direction, the boom 6 is caused to rotate on the roll base 5 via the hydraulic cylinder 71 in the roll direction. Power works. At this time, the boom 6 tries to stay in place by the inertial force, so the hydraulic cylinder 71 expands and contracts by the inertial force of the boom 6 and absorbs the tilt of the work vehicle 1.

  If the hydraulic cylinder 71 cannot absorb the inclination of the work vehicle 1 and the force due to the gas pressure difference between the pressure accumulating chambers 77B and 78B of the first accumulator 77 and the second accumulator 78 exceeds the inertial force of the boom 6, the boom 6 rolls. To do. However, the roll vibration is quickly damped by the first damping valve 81 and the second damping valve 82. In this way, since the change in the force acting on the roll base 5 from the work vehicle 1 is alleviated by the expansion and contraction of the hydraulic cylinder 71, the boom 6 can be prevented from rotating significantly in the roll direction, and the tip of the boom 6 can be Etc. are prevented from colliding with each other.

  Further, as the hydraulic cylinder 71 expands and contracts, the first damping valve 81 and the second damping valve 82 provide resistance to the flow of hydraulic oil entering and leaving the first accumulator 77 and the second accumulator 78. The boom 6 is prevented from vibrating in the roll direction. Thereby, the control liquid sprayed from the nozzle of the boom 6 can be uniformly sprayed.

  As described above, when the centering operation for holding the boom 6 in the horizontal direction is continued, the hydraulic oil in the second chamber 76 gradually leaks due to deterioration of the seal over time, and the amount of oil in the second chamber 76 is reduced. May be reduced. As a result, when the boom 6 is in the horizontal direction, the pressure in the second chamber 76 is reduced and the spring constant is reduced, so that the centering force of the hydraulic cylinder 71 is reduced, and the piston 73 and the rod 74 seals are slid. The variation in centering position increases due to the effect of friction.

  Therefore, even if the boom 6 is set horizontally before the work, the boom 6 is inclined from the horizontal direction during the work, so that the spraying of the control liquid is likely to be uneven.

  Therefore, in this case, a replenishment operation for replenishing hydraulic oil to the second chamber 76 of the hydraulic cylinder 71 is performed.

  Hereinafter, the hydraulic oil replenishment operation will be described.

  First, after the work vehicle 1 is parked horizontally, the driver manually fixes the boom 6 in the horizontal direction. A fixing jig 52 as shown in FIG. 5A is used for fixing the boom 6. Further, instead of the fixing jig 52, a fixing jig 53 as shown in FIG. 5B may be used.

  As shown in FIG. 5A, the driver rotates the boom 6 so that the roll base 5 is parallel to the lift base 4, and the U-shaped fixing jig 52 is moved from the front of the work vehicle 1 to the roll base 5 and By fitting in the lifting platform 4, the rotation of the boom 6 is restricted.

  Further, as shown in FIG. 5B, the driver rotates the boom 6 so that the roll table 5 is parallel to the lift table 4, and penetrates the roll table 5 and the lift table 4 in the front-rear direction of the work vehicle 1. By rotating the boom 6 by making each through hole (not shown) face each other and inserting a pin-shaped fixing jig 53 into the through hole of the roll base 5 and the through hole of the lifting base 4 from the front of the work vehicle 1. To regulate.

  Next, returning to FIG. 4, with the boom 6 fixed in the horizontal direction, the direction switching valve 94 is switched to the left roll position a and the needle valve 84 is opened. As a result, the discharge pressure from the hydraulic pump 93 is guided to the connection passage 83 via the operation passage 97 and the second chamber 76 of the hydraulic cylinder 71 is replenished with hydraulic oil. Since the pressure in the connection passage 83 is maintained at the set pressure at which the relief valve 86 opens, the pressure in the second chamber 76 becomes the set pressure.

  Further, since the discharge pressure of the hydraulic pump 93 is guided as a pilot pressure to the operation check valve 92 via the operation passage 97, the operation check valve 92 is opened, and the hydraulic oil in the first chamber 75 is discharged into the supply / discharge passage 91, It is returned to the tank T through the passage 96.

  At this time, the pressure in the second chamber 76 rises to the set pressure by replenishing the hydraulic oil that has been reduced due to leakage, so that a differential pressure is generated between the first chamber 75 and the first chamber 75. This differential pressure causes the piston 73 to receive an oil pressure upward in FIG. 4, but the rotation of the roll base 5 is regulated by the fixing jigs 52 and 53. It acts on the contact part with the stand 5 and the lift 4 and the boom 6 does not rotate.

  Subsequently, after closing the needle valve 84, the direction switching valve 94 is switched to the neutral position c. This completes the setting of the second chamber 76 to the set pressure. Thereafter, the direction switching valve 94 is switched to the right roll position b. As a result, the hydraulic oil discharged from the hydraulic pump 93 flows into the first chamber 75 through the supply passage 95 and the supply / discharge passage 91. In this case, the pressure of the hydraulic oil flowing into the first chamber 75 is a pressure whose upper limit is the set pressure of the relief valve 99 and is higher than the set pressure of the relief valve 86.

  Thereafter, when the pressure difference between the first chamber 75 and the second chamber 76 is eliminated, the direction switching valve 94 is switched to the neutral position c. Thereby, since the first chamber 75 and the second chamber 76 have the same pressure, the hydraulic pressure acting on the contact portion between the fixing jigs 52 and 53 and the roll table 5 and the lifting table 4 is released.

  The timing for switching to the neutral position c after switching the direction switching valve 94 to the right roll position b may be determined based on a preset time, or the driver pulls out the fixing jigs 52 and 53. Switching may be performed when a force is applied in the direction and the fixing jigs 52 and 53 are detached.

  After the direction switching valve 94 is switched to the neutral position c, the fixing work 52, 53 is removed to complete the hydraulic oil replenishment operation.

  According to the above embodiment, there exist the effects shown below.

  By switching the direction switching valve 94 to the left roll position a and opening the needle valve 84, the hydraulic oil in the connection passage 83 held at the set pressure can be supplied to the second chamber 76, so that the hydraulic cylinder 71 is contained. Even if the amount of oil in the second chamber 76, which is the hydraulic chamber on the other side, leaks and decreases, the hydraulic oil can be easily replenished. Thereby, the centering force of the hydraulic cylinder 71 can be recovered, and variations in the centering position due to the influence of friction when the piston 73 slides can be suppressed. Therefore, since the boom 6 is held in the horizontal direction during the operation, the control liquid can be sprayed evenly.

  Further, since the hydraulic oil in the second chamber 76 leaked by switching the direction switching valve 94 and opening the needle valve 84 can be replenished, the hydraulic cylinder 71 is disassembled and hydraulic oil is replenished after the hydraulic oil is replenished as in the prior art. There is no need to reassemble the cylinder 71. Therefore, the replenishment work of hydraulic oil can be simplified.

  Furthermore, since the hydraulic oil is replenished in a state where the boom 6 is fixed in the horizontal direction by the fixing jigs 52 and 53, the pressure in the second chamber 76 is set to the set pressure only by holding the pressure in the connection passage 83 at the set pressure. Can be filled with. Therefore, the replenishment work of hydraulic oil can be simplified.

  Further, after supplying the hydraulic oil in the connection passage 83 held at the set pressure to the second chamber 76, the needle valve 84 is closed, and then the direction switching valve 94 is switched to the right roll position b, so that the first chamber 75 and the first chamber When the pressure difference between the two chambers 76 is eliminated, the direction switching valve 94 is switched to the neutral position c. As a result, it is difficult to remove the fixing jigs 52 and 53 due to the oil pressure acting in accordance with the differential pressure generated between the second chamber 76 and the first chamber 75 when the hydraulic oil is replenished to the second chamber 76 and the pressure is increased. Can be prevented.

  Next, a second embodiment will be described.

  In the present embodiment, the fixing jigs 52 and 53 are not used during the hydraulic oil replenishment operation. Furthermore, the valve opening pressure of the relief valve 86 is different from that of the first embodiment. Other points are the same as in the first embodiment.

  The opening pressure of the relief valve 86 is set in the first embodiment by an amount corresponding to the pressure increase in the second chamber 76 when the hydraulic cylinder 71 is moved halfway from the stroke end on the first chamber 75 side to the second chamber 76 side. An initial set pressure lower than the pressure is set.

  Below, the replenishment operation | work of the hydraulic oil different from 1st Embodiment is demonstrated.

  First, after the work vehicle 1 is parked horizontally, the boom 6 is folded and stored so that the boom 6 extends in the front-rear direction along the side of the work vehicle 1. The boom 6 may be stored manually by the driver, or the controller may transmit a command to an actuator that stores the boom 6 based on a signal transmitted from the operation switch.

  Next, the direction switching valve 94 is switched to the left roll position a and the needle valve 84 is opened. As a result, the discharge pressure from the hydraulic pump 93 is guided to the connection passage 83 via the operating passage 97, and further to the second chamber 76 from the connection passage 83. Further, since the discharge pressure of the hydraulic pump 93 is guided as a pilot pressure to the operation check valve 92 via the operation passage 97, the operation check valve 92 is opened, and the hydraulic oil in the first chamber 75 is discharged into the supply / discharge passage 91, It is returned to the tank T through the passage 96.

  Since the rotation of the boom 6 is not fixed, the piston 73 moves upward in FIG. 4 as the pressure in the second chamber 76 increases, and the boom 6 rotates in the left roll direction. When the piston 73 moves to the stroke end on the first chamber 75 side, the rotation of the boom 6 stops, and the second chamber 76 is filled with the initial set pressure that is the valve opening pressure of the relief valve 86.

  In this state, the needle valve 84 is closed. Thereby, the second chamber 76 is maintained at the initial set pressure. Subsequently, the direction switching valve 94 is switched to the right roll position b. As a result, the discharge pressure from the hydraulic pump 93 is guided to the first chamber 75 via the supply / discharge passage 91, and the piston 73 moves downward in FIG. 4 while compressing the second chamber 76. Along with this, the boom 6 rotates in the right roll direction.

  The driver switches the direction switching valve 94 to the neutral position c when the boom 6 becomes horizontal. With the above operation, the hydraulic cylinder 71 is moved halfway from the stroke end on the first chamber 75 side to the second chamber 76 side, so that the pressure in the second chamber 76 is equal to the pressure increase in the second chamber 76 due to this stroke. The initial set pressure rises to the set pressure, and the hydraulic oil replenishment operation is completed.

  According to the above embodiment, there exist the effects shown below.

  The hydraulic oil is replenished to the second chamber 76 while rotating the boom 6 without using the fixing jigs 52 and 53. At this time, the second chamber 76 is previously filled with an initial set pressure lower than the set pressure, and then the replenishment operation is performed so that the second chamber 76 is set to the set pressure by supplying the hydraulic pressure to the first chamber 75. Is called. Thereby, even if the amount of oil in the second chamber 76 which is the hydraulic chamber on the sealed side of the hydraulic cylinder 71 leaks and decreases, the hydraulic oil can be easily replenished. Thereby, the centering force of the hydraulic cylinder 71 can be recovered, and variations in the centering position due to the influence of friction when the piston 73 slides can be suppressed. Therefore, since the boom 6 is held in the horizontal direction during the operation, the control liquid can be sprayed evenly.

  Furthermore, when the replenishment operation is performed with the boom 6 fixed with a jig or the like, the jig or the like can be removed by the differential pressure between the first chamber 75 and the second chamber 76, and the boom 6 can be rotated unexpectedly. However, in the present embodiment, since the replenishment operation is performed while the boom 6 is intentionally rotated, the safety during the replenishment operation of the hydraulic oil can be ensured more reliably.

  The embodiment of the present invention has been described above. However, the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  For example, in the above embodiment, the electromagnetic direction switching valve 94 is illustrated, but a mechanical direction switching valve whose position is switched based on a lever operation by the driver may be used.

1 Working Vehicle 6 Boom 7 Boom Damping Device 52 Fixing Jig
53 Fixing jig
71 Hydraulic cylinder (fluid pressure cylinder)
75 Room 1 (One Room)
76 Room 2 (the other room)
77 First accumulator (first accumulator)
78 Second accumulator (second accumulator)
83 Connection passage 84 Needle valve (open / close valve)
85 Relief passage 86 Relief valve 92 Operate check valve 94 Directional switching valve (switching valve)
97 Operate passage (pilot passage)
100 spraying equipment

Claims (5)

A boom damping device that suppresses vibration of a boom that is rotatable in the roll direction of a work vehicle,
A fluid pressure cylinder coupled to the work vehicle and the boom, and extending and contracting in conjunction with the boom rotating in a roll direction of the work vehicle;
A first pressure accumulator that pressurizes one chamber of the fluid pressure cylinder and in which a working fluid enters and exits as the fluid pressure cylinder expands and contracts;
A second pressure accumulator that pressurizes the other chamber of the fluid pressure cylinder and allows working fluid to enter and exit as the fluid pressure cylinder expands and contracts;
A switching valve capable of switching between a supply position for supplying the working fluid to the one chamber and a discharge position for discharging the working fluid from the one chamber;
The switching valve is interposed in a supply / discharge passage connecting the one chamber, and when the switching valve is in the supply position, only the flow of the working fluid from the switching valve to the one chamber is allowed, and the switching is performed. An operation check valve that allows the flow of the working fluid from the one chamber to the switching valve using the working fluid pressure supplied from the switching valve via the pilot passage when the valve is in the discharge position as a pilot pressure;
An on-off valve capable of opening and closing a connection passage connecting the pilot passage and the other chamber;
A relief valve that is interposed in a relief passage that branches from between the pilot passage and the on-off valve in the connection passage, and holds the working fluid pressure in the connection passage at a set pressure when the switching valve is in the discharge position. When,
With
By switching the switching valve to the discharge position and opening the on-off valve, the working fluid in the connection passage maintained at a set pressure is supplied to the other chamber.
Boom damping device characterized by that. The switching valve is switched to the discharge position and the opening / closing valve is controlled in a state where the rotation of the boom is restricted by a jig for fixing the boom in a horizontal direction by restricting the rotation of the boom with respect to the work vehicle. By opening, supply the working fluid of the connection passage held at the set pressure to the other chamber,
The boom vibration control device according to claim 1. After supplying the working fluid in the connection passage held at the set pressure to the other chamber, the open / close valve is closed and the switching valve is switched to the supply position, whereby the difference between the one chamber and the other chamber is reached. Supplying a working fluid to the one chamber until the pressure is released;
The boom damping device according to claim 2, wherein The relief valve sets the working fluid pressure in the connection passage to an initial set pressure lower than the set pressure by an amount corresponding to an increase in the pressure in the other chamber when the fluid pressure cylinder strokes by half from the stroke end on the one chamber side. Hold and
By switching the switching valve to the discharge position and opening the on-off valve, the working fluid in the connection passage maintained at the initial set pressure is supplied to the other chamber, and the fluid pressure cylinder is moved to the one chamber side. The stroke chamber is closed and then the on-off valve is closed and the switching valve is switched to the supply position. Supply working fluid to
The boom vibration control device according to claim 1.   A spraying device that comprises the boom damping device according to any one of claims 1 to 4 and sprays the control liquid.

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