JP2008184787A - Cargo gear of cargo vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily perform loading operation such as banking operation for loading cargos to a low position. <P>SOLUTION: This cargo gear of a cargo vehicle comprises an operation boom attached to a vehicle body swung by a boom cylinder 16 in the vertical direction, a bucket attached to the distal end of the operation boom tiltably in the longitudinal direction, and a level holding device 31 for holding the bucket horizontally by feeding a part of the pressure oil discharged from the boom cylinder 16 into a cargo handling cylinder 18 to tilt the bucket forward. The level holding device 31 comprises a high-speed forward tilting mechanism 50 having a high-speed forward tilting valve 52 for adjusting the amount of the pressure oil fed from the boom cylinder 16 into the cargo handling cylinder 18 when the operation boom is swung upward; and a high-speed forward tilting switch 54 for operating the high-speed forward tilting valve 52. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention keeps the level of the load handling equipment to prevent spillage by holding the load handling equipment such as a bucket and lifting the work equipment by swinging the work boom upward and lifting the work equipment. The present invention relates to a cargo handling device for a cargo handling vehicle including the device.

  The work boom provided on the vehicle body is swung in the vertical direction, and the bucket provided at the free end of the work boom is tilted in the front-rear direction to provide a small load handling device that handles loads such as earth and sand. A wheel loader is disclosed in Patent Document 1, for example. 7 and 8, the small wheel loader has left and right driving front wheels 12F provided at the front portion of the vehicle body 11 and left and right driving rear wheels 12R provided at the rear portion. The front and rear wheels 12F and 12R are operated by a pair of left and right travel control levers 21R and 21L provided in the front cockpit 13 to move forward and backward, and the rotational speed difference between the left and right drive front and rear wheels 12F and 12R. It is comprised so that the vehicle body 11 may be steered using.

  A pair of left and right work booms 14 are provided on both sides of the rear portion of the vehicle body 11 so as to be swingable in the vertical direction via horizontal support shafts 15 in the horizontal direction and extend forward through the left and right sides of the cockpit 13. ing. Boom cylinders 16 are respectively connected between an L-shaped front support portion 14 a provided on the free end side of these work booms 14 and the vehicle body 11, and the work boom 14 causes the horizontal support shaft 15 to be connected by these boom cylinders 16. It is swung up and down about the center. Further, between the front support portions 14a of the left and right work booms 14, for example, a bucket 17 as a work tool is supported to be tiltable in the front-rear direction via a support pin 17a parallel to the horizontal support shaft 15, and further, the front support portion 14a By the cargo handling cylinder 18 provided between the bucket 17 and the bucket 17, the bucket 17 is tilted in the front-rear direction around the support pin 17a.

  Further, the control seat 13 is provided with the traveling operation levers 21R and 21L and a pair of left and right cargo handling operation pedals 22R and 22L for swinging the work boom 14 up and down and tilting the bucket 17 back and forth.

  Normally, in this wheel loader, the traveling operation levers 21R and 21L are operated with both hands to perform traveling and steering, and the cargo handling operation pedals 22R and 22L are operated with both feet to load a high load receiving platform such as a truck. Cargo handling work such as.

In such a loading operation, when the work boom 14 is swung upward, the bucket 17 tilts backward to cause spillage. Therefore, it is necessary to perform the forward tilting operation of the bucket 17 simultaneously with the raising operation of the work boom 14. . In order to avoid such combined operation of the work boom 14 and the bucket 17 by the cargo handling operation pedals 22R and 22L, the bucket 17 is automatically tilted forward as the work boom 14 is lifted and held horizontally to prevent spillage. A holding device is provided.
Japanese Patent Laid-Open No. 5-51940

  However, in this type of small wheel loader, in addition to loading work on a high loading platform such as a truck, the load of soil, materials, compost, etc. scraped or scooped up in farming work or civil engineering work, etc. It is often used for low-level loading operations, such as lifting up to a very low level of about 2 m and placing it.

  In this case, in the conventional level holding device, since the bucket 17 is automatically held horizontally throughout the lifting and lowering stroke of the bucket 17, when the bucket 17 is tilted forward from this horizontal posture and the earth and sand are dropped, It takes time to load. In order to carry out the loading operation in a short time, the skilled person raises the work boom 14 and simultaneously tilts the bucket 17 at the same time by combining the load handling operation pedals 22R and 22L with both feet. A skilled operator can perform work in a short time by this combined operation, but there is a problem that a complex operation is difficult for an operator with a low level of skill and a long time is required for a low-level loading operation.

  An object of the present invention is to solve the above-described problems and to provide a cargo handling device for a cargo handling vehicle that can easily perform low-level loading work such as embankment in a short time regardless of skill level.

  According to the first aspect of the present invention, there is provided a work boom provided on the vehicle body so as to be swingable in the vertical direction around a horizontal support shaft, and a cargo handling tool provided on the free end portion of the work boom so as to be tiltable in the front-rear direction. And a boom cylinder that can swing the work boom up and down to drive the load handling equipment up and down, a cargo handling cylinder that can tilt the work handling equipment in the front-rear direction, and a boom when the work boom is swung upward by the boom cylinder. A leveling device for a cargo handling vehicle, comprising: a level holding device that supplies a part of the pressure oil discharged from the cylinder to the cargo handling cylinder to operate and tilts the cargo handling tool forward to hold the cargo handling tool horizontally. The holding device is provided with a high-speed forward tilt mechanism, which adjusts the amount of pressure oil sent from the boom cylinder to the cargo handling cylinder when the work boom is swung upward by the boom cylinder. When those having a high-speed anteversion switch for operating the high-speed anteversion valve.

  According to a second aspect of the present invention, in the configuration according to the first aspect, the level holding device includes a first port connected to the control valve, a second port connected to the contraction chamber of the boom cylinder, and the progress of the cargo handling cylinder. A third port connected to the chamber, a branch valve interposed in a main flow path connecting the first port and the second port, and an adjustment flow path connecting the branch port of the branch valve and the third port The high-speed forward tilt mechanism includes a bypass flow path that connects the main flow path and the adjustment flow path between the branch valve and the second port and interposes a high-speed forward tilt valve.

  According to a third aspect of the present invention, in the configuration according to the first or second aspect, the high-speed forward tilting mechanism is configured such that the additional amount of the pressure oil can be adjusted in a plurality of stages or continuously.

  According to the configuration of claim 1, in the level holding device, the amount of pressure oil discharged from the boom cylinder, separated by the branch valve and sent to the cargo handling cylinder is set for high-speed forward tilting, and the high-speed forward tilt switch When the high-speed forward tilting valve is shut off by operating, the entire amount of pressure oil separated by the branch valve is supplied to the cargo handling cylinder, and the cargo handling cylinder is driven at high speed to tilt the cargo handling equipment forward at high speed. In addition, when the normal horizontal level is maintained by operating the high-speed forward tilt switch to connect the high-speed forward tilt valve, the high-speed drive of the pressure oil separated by the branch valve is returned to the discharge side, thereby reducing the drive speed of the cargo handling cylinder. To reduce the forward tilting speed of the cargo handling equipment and hold it in a horizontal position. Therefore, regardless of the skill level, by operating the high-speed forward tilt switch, it is possible to easily carry out low-level loading work such as embankment in a short time.

According to the configuration of the second aspect, the high-speed forward tilt mechanism can be easily provided in the level holding device by the bypass passage having the high-speed forward tilt valve.
According to the configuration of claim 3, since the additional amount of pressure oil can be adjusted in a plurality of stages or steplessly, it is possible to select and set the dropping position of the load by the cargo handling equipment, and to perform the loading operation at a low position. Furthermore, it can be performed efficiently and in a short time.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[Embodiment 1]
A first embodiment of a cargo handling apparatus for a cargo handling vehicle according to the present invention will be described with reference to FIGS. Note that the same members as those in the conventional example are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 1 is a hydraulic circuit diagram of a cargo handling device that drives the boom cylinder 16 and the cargo handling cylinder 18. As shown in FIG. 1A, a pressure oil supply pipe 45A with a hydraulic pump 44 driven by an engine interposed is connected between the tank 40 and a port P on the inlet side of the control valve 41, and the tank 40 and the control valve 41 are controlled. A pressure oil discharge pipe 45 </ b> B is connected to the port T of the valve 41.

  Further, as shown in FIG. 1C, the control valve 41 includes a boom operation valve 42 and a cargo operation valve 43 operated by the cargo operation pedals 22R and 22L, and is connected to the boom operation valve 42 on the outlet side. Ports A1 and B1 and outlet-side ports A2 and B2 connected to the cargo handling operation valve 43 are provided.

  The boom operating valve 42 is connected to the port P and the port of the cargo handling valve 43 by the cargo handling operation pedal 22R (or 22L), and to the boom free position A and the port P which connect the ports A1, B1 and the port T. And a boom lowering position B for connecting the port B1 and the port of the cargo handling operation valve 43, and a boom for closing the port A1 and the port B1 and connecting the port P and the port of the cargo handling operation valve 43. The stop position C is operated to a boom raising position D that connects the port P and the port B1 and connects the port A1 and the port of the cargo handling operation valve 43.

  In addition, the cargo handling operation valve 43 closes the cargo handling forward tilting position a that connects the port P and the port A2 and connects the port T and the port B2, and the port A2 and the port B2 by the cargo handling operation pedal 22L (or 22R). The cargo handling stop position b to be operated and the cargo handling tilted position c which connects the port P and the port B2 and connects the port A2 and the port T are operated.

The control valve 41 and the boom cylinder 16 are connected to a boom raising pipe 36A between the port B1 and a progress chamber (also referred to as a tail chamber) 16r, and a contraction chamber (also referred to as a front chamber) 16f and a port of the boom cylinder 16 are connected. between the A1, the first boom down pipe 36B ₁ and the second boom down pipe 36B ₂ and are connected in series. In addition, the control valve 41 and the cargo handling cylinder 18 are connected to a port A2 and an expansion chamber (also referred to as a tail chamber) 18r of the cargo handling cylinder 18 with a forward-tilting pipe 37A, and the port B2 and the contraction chamber of the cargo handling cylinder 18 ( A cargo handling rearwardly inclined pipe 37B is connected to 18f.

A level holding device 31 is provided between the first and second boom lowering pipes 36B ₁ and 36B ₂ and the cargo handling pre-tilt pipe 37A and the cargo handling pre-tilt pipe 37B.
The level holding device 31 includes a port second boom down pipe 36B ₂ is connected I (first port) and port II of the first boom down pipe 36B ₁ is connected (second port), handling backward tilting A port III connected to the second branch pipe 34 connected to the pipe 37B and a port IV (third port) connected to the first branch pipe 33 connected to the forward-tilting pipe 37A are provided. . A branch valve (spool valve) 32 is interposed in the first and second main flow paths (main flow paths) 31a and 31b that connect the port I and the port II. An adjustment check valve 38 that allows the flow of pressure oil only from the branch valve 32 to the port IV is interposed in the adjustment flow path 31c that connects the branch port of the branch valve 32 and the port IV. Further, an unload valve 35 is interposed in a return flow path 31d that connects the port III and the second main flow path 31b.

  A bypass flow path 51 is connected from the second main flow path 31b to an adjustment flow path 31c between the adjustment check valve 38 and the branch port of the branch valve 32. A solenoid-type high-speed forward tilt valve is connected to the bypass flow path 51. 52, and a high-speed forward tilt check valve 53 that allows the flow of pressure oil only from the high-speed forward tilt valve 52 to the second main flow path 31b is interposed on the second main flow path 31b side of the high-speed forward tilt valve 52. Has been.

  The bypass channel 51, the high-speed forward tilt valve 52, the high-speed forward tilt check valve 53, and the switching operation between the i position provided on the cockpit 13 and blocking the high-speed forward tilt valve 52 are connected. The high-speed forward tilting mechanism 50 is configured by the high-speed forward tilting switch 54.

  The branch valve 32 discharges the pressure oil discharged from the contracting chamber 16f of the boom cylinder 16 and flowing into the port I to the port A1 of the control valve 41 through the throttle portion when the boom cylinder 16 is advanced. At the same time, a part of the pressure oil is separated into a predetermined ratio at which the cargo handling cylinder 18 can be driven at a high speed, sent to the adjustment flow path 31c, discharged from the port IV to the first branch pipe 33, and the tail chamber 18r of the cargo handling cylinder 18 It is comprised so that it may supply. The high-speed forward tilt check valve 53 is at the ii position, and among the amount of pressure oil sent from the adjustment passage 31c to the cargo handling cylinder 18 by the throttle portion, only the amount of pressure oil for high-speed driving is supplied to the second main passage 31b side. In this case, only the amount of pressure oil that is held horizontally is supplied to the tail chamber 18r of the cargo handling cylinder 18.

  For example, when the normal level of the bucket 17 is maintained, the amount of pressure oil sent to the cargo handling cylinder 18 is 0.3 with respect to 1.0 of the first main flow path 31a, and the amount of pressure oil when tilting forward at high speed is 0. .5 (0.2 for high-speed drive), the amount of pressure oil separated to the adjustment flow path 31c side by the branch valve 32 is 0.5 (the first flow rate relative to 1.0 of the first main flow path 31a). 2 main flow path 31b: adjustment flow path 31c = 1: 1), and the amount of pressure oil discharged from the high-speed forward tilt check valve 53 (for high-speed drive) is set to 0.2.

Incidentally, when contracting the boom cylinder 16, the control pressure oil flowing into the port II via the first boom down pipe 36B ₁ is supplied from the port A1 of the valve 41, the spool (FIG branch valve 32 by the hydraulic pressure Shimese it not) by closing the pressing operation to the branch port to the total amount without being separated is sent to the port I side, supplied from the second boom down pipe 36B ₂ to shrinkage chamber 16f of the boom cylinder 16.

The unloading valve 35 is supplied with pressure oil to the progress chamber 18r of the cargo handling cylinder 18 via the first branch pipe 33, so that the pressure oil discharged from the contraction chamber 18f of the cargo handling cylinder 18 is controlled by the control valve 31. From the position i where the second branch pipe 34 is shut off due to an increase in the hydraulic pressure of the first branch pipe 33 when it is not discharged from the tank 40 (when the cargo handling valve 43 is in the cargo handling stop position b). 34 is switched to the ii position that communicates. As a result, the pressure oil flowing into the port III via the second branch pipe 34 discharged from the contraction chamber 18f of the cargo handling cylinder 18 is transferred from the unload valve 35 of the return flow path 31d to the port via the second main flow path 31b. discharged to II, further turned out from the first boom down pipe 36B ₁ to the port A1 of the control valve 31 is discharged from the boom operating valve 42 to the tank 40.

In the above configuration, the boom operating valve 42 of the control valve 41 is operated to the boom raising position D by the cargo handling operation pedal 22R, and pressure oil is supplied from the port B1 of the control valve 41 to the progress chamber 16r of the boom cylinder 16 via the boom raising pipe 36A. Supply. As a result, the boom cylinder 16 is advanced from the lowered position G in which the load such as earth and sand and shear is loaded by the bucket 17, the work boom 14 is swung upward, and the bucket 17 is raised. Then, the pressure oil discharged from the shrinkage chamber 16f of the boom cylinder 16 is discharged to the sent tank 40 to the port A1 of the control valve 41 via the branch valve 32 of the level holding device 31 from the second boom down pipe 36B ₂ The At this time, a part of the pressure oil discharged to the second boom down pipe 36B ₂ is sent to the first branch pipe 33 from the branch port of the branch valve 32, the progress of the cargo handling cylinder 18 via the cargo handling before傾配tube 37A It is supplied to the chamber 18r. As shown in FIG. 1 (a), when normal horizontal level maintenance is selected by the high-speed forward tilt switch 54 and the high-speed forward tilt valve 52 is in the ii position, The high-speed drive is returned to the second main flow path 31b via the bypass flow path 51, whereby the bucket 17 is tilted forward at a low speed by the cargo handling cylinder 18 and held horizontally.

  If the high-speed forward tilt switch 54 is selected by the high-speed forward tilt switch 54 and the high-speed forward tilt valve 52 is switched from the ii position to the i position as shown in FIG. The entire amount of pressure oil flowing through the main flow path 31b is sent from the port IV to the progress chamber 18r of the cargo handling cylinder 18 via the first branch pipe 33. As a result, as shown in FIG. 3, the bucket 17 is tilted forward at a high speed, the bucket 17 is completely tilted forward at the raised position U lower than usual, and the load such as earth and sand accommodated in the bucket 17 is short. It slides down in time.

  Therefore, when a simple operation of unloading to a low position is repeatedly performed such as a filling operation, the forward tilting operation of the bucket 17 can be automatically performed at a higher speed only by operating the high speed forward tilt switch 54. Even if it is not an expert, it can perform low-order loading work efficiently in a short time.

[Embodiment 2]
In the first embodiment, the amount of pressure oil returned to the second main flow path 31b from the adjustment flow path 31c via the bypass flow path 51 is constant by the high-speed forward tilt valve 52, so the forward tilt speed of the bucket 17 is selected. However, in the second embodiment, the forward tilt speed of the bucket 17 can be selected in a plurality of stages (three stages), and the height position of the unloading can be selected. .

  That is, as shown in FIG. 4, in the bypass flow path 51, a first high-speed forward tilt valve 61 with a small passage flow rate by the throttle portion and a second high-speed forward tilt flow rate by the throttle portion that is larger than the first high-speed forward tilt valve 61. The tilt valve 62 is interposed in parallel, and the first and second high-speed forward tilt valves 61 and 62 are operated by the high-speed forward tilt switch 64 via the switch controller 63, respectively. Then, the amount of pressure oil separated to the adjustment flow path 31c side by the branch valve 32 is set to the amount of pressure oil that can tilt the bucket 17 forward at the highest speed, and the first high-speed forward tilt valve 61 and the second high-speed forward tilt The amount of pressure oil in the bypass flow passage 51 when it is returned to the second main flow passage 31b by the valve 62 is set so as to have a forward tilting speed for holding the bucket 17 in a horizontal posture.

  The high-speed forward tilt switch 64 is a momentary type and an illumination type that continues to be turned on when it is pressed once. A button 64b for low-speed forward tilting that communicates by switching, a B button 64c for medium-speed forward tilting that switches and communicates only the second high-speed forward tilting valve 62 to the ii position, the first high-speed forward tilting valve 61, and the first 2. A high-speed forward A + B button 64d for switching the high-speed forward tilt valve 62 to the ii position and communicating is provided, and these buttons 64a to 64d are selected to select the forward tilt speed of the bucket 17 in three stages. be able to.

  In the switch controller 63, by pressing any of these A, B, A + B buttons 64b to 64d, the respective relays RY-A, RY-B, RY-C are operated, and the respective contacts are turned on / off. Thus, the lamps L of the A, B, A + B buttons 64b to 64d are turned on / off, and the solenoids 61s, 62s of the first and second high-speed forward tilt valves 61, 62 are turned on / off. .

  According to the second embodiment, since the forward tilt speed of the bucket 17 can be selected in a plurality of stages, the height position of the unloading can be appropriately selected, and even if it is not an expert, it is more efficient. Low-level loading work can be performed.

  As another embodiment, as shown in FIG. 5, an electromagnetic proportional control type high speed forward tilt valve (for example, proportional valve) 71 is provided instead of the high speed forward tilt valve 52, and this proportional control type high speed forward tilt valve is provided. By configuring the valve 71 so that it can be operated by the high-speed forward tilt switch 73 via the switch controller 72, the forward tilt speed of the bucket 17 can be selected in a stepless manner, and the unloading height gradually increases. Thus, by selecting a more optimal forward tilting speed of the bucket 17, an appropriate unloading height can always be set, and a low-level loading operation can be performed efficiently.

  In the first and second embodiments, the bucket 17 is used as a cargo handling device, but the present invention is not limited to this, and the pallet fork 19A shown in FIG. 6 (a), the fork grapple 19B shown in FIG. 6 (b), As long as it is a wing bucket 19C shown in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS It is a hydraulic circuit diagram which shows Embodiment 1 of the cargo handling apparatus of the cargo handling vehicle which concerns on this invention, (a) shows the flow of the pressure oil when selecting horizontal level maintenance of a bucket at the time of a boom rise, (b) The flow of pressure oil in the level holding device when high-speed tilting with the bucket is selected is shown, and (c) shows the flow of pressure oil in the control valve when the boom is raised. In the hydraulic circuit diagram of the cargo handling device, (a) shows the flow of pressure oil when the boom is lowered, and (b) shows the flow of pressure oil of the control valve when the boom is lowered. It is a side view of the cargo handling vehicle which shows operation | movement of the bucket of a cargo handling apparatus. It is a circuit diagram of the cargo handling apparatus showing Embodiment 2 of the cargo handling apparatus, (a) shows the hydraulic circuit of the level adjusting device, (b) shows the electric circuit of the high-speed forward tilt switch and the switch controller. It is a piping diagram of a level adjusting device showing another embodiment of the cargo handling device. It is a perspective view which shows the other form of a cargo handling tool, (a) is a pallet fork, (b) is a fork grapple, (c) is a wing bucket. It is a whole side view of the conventional cargo handling vehicle. It is a whole front view of the conventional cargo handling vehicle.

Explanation of symbols

11 Car body 12F Driving front wheel 12R Driving rear wheel 13 Pilot seat 14 Work boom 15 Support shaft 16 Boom cylinder 17 Bucket 18 Carrying cylinders 21R, 21L Traveling operation levers 22R, 22L Handling operation lever 31 Level holding device 31a First main flow path 31b Second Main flow path 31c Adjustment flow path 32 Branch valve 33 First branch pipe 34 Second branch pipe 35 Unload valve 36A Boom rise pipe 36B ₁ First boom drop pipe 36B ₂ Second boom drop pipe 37A Bucket forward tilt pipe 37B Bucket tilt backward Piping 38 Adjustment check valve 41 Control valve 42 Boom operation valve 43 Cargo operation valve 44 Hydraulic pump 45A Pressure oil supply pipe 45B Pressure oil discharge pipe 50 High-speed forward tilt mechanism 51 Bypass passage 52 High-speed forward tilt valve 53 High-speed forward tilt check valve 54 High-speed forward tilt switch 61 First high-speed forward tilt valve 62 Second high speed forward tilt valve 61s, 62s Solenoid 63 Switch controller 71 Proportional control type high speed forward tilt valve 72 Switch controller 73 High speed forward tilt switch

Claims (3)

A work boom provided on the vehicle body so as to be swingable in the vertical direction around a horizontal support shaft, a cargo handling tool provided on the free end of the work boom so as to be tiltable in the front-rear direction, and the work boom in the vertical direction. A boom cylinder that can swing up and down to lift the loader, a loader cylinder that can tilt the loader in the front-rear direction, and hydraulic oil discharged from the boom cylinder when the boom is swung upward by the boom cylinder. In a cargo handling device for a cargo handling vehicle comprising a level holding device that supplies a part to a cargo handling cylinder to operate and tilts the cargo handling tool forward to hold the cargo handling tool horizontally.
A high-speed forward tilt mechanism is provided in the level holding device,
The high-speed forward tilt mechanism includes a high-speed forward tilt valve that adjusts the amount of pressure oil sent from the boom cylinder to the cargo handling cylinder when the work boom is swung upward by the boom cylinder, and a high-speed forward tilt valve that operates the high-speed forward tilt valve. A cargo handling device for a cargo handling vehicle having a tilt switch. The level holding device includes a first port connected to the control valve, a second port connected to the contraction chamber of the boom cylinder, a third port connected to the progress chamber of the cargo handling cylinder, a first port, and a second port. A branch valve interposed in the main flow path connecting the port, and an adjustment flow path connecting the branch port of the branch valve and the third port,
The cargo handling device for a cargo handling vehicle according to claim 1, wherein the high-speed forward tilting mechanism has a bypass flow path that connects the main flow path and the adjustment flow path between the branch valve and the second port and intervenes the high-speed forward tilt valve. . The cargo handling apparatus for a cargo handling vehicle according to claim 1, wherein the high-speed forward tilt mechanism is configured to be capable of adjusting an additional amount of pressure oil in a plurality of stages or steplessly.

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