JP5133733B2 - Work vehicle - Google Patents

Description

  The present invention includes a cylinder formed by connecting a piston rod inside a cylinder case and slidably provided in a cylinder liner to a piston rod having a rear end connected to a lift crank, and a front of the cylinder. A cylinder head that is connected to the installed cylinder liner and has a flow hole through which hydraulic fluid flows, and a spool that is installed in the control valve in the vicinity of the cylinder head and slides on a spool provided on the control valve. And an operation link case having an operation link mechanism for supplying or stopping hydraulic oil in the cylinder liner, and a work vehicle equipped with a hydraulic lifting device for raising and lowering the work implement on the transmission case. More specifically, the hydraulic elevating device is a work vehicle including a cylinder portion formed by integrally forming a cylinder and a cylinder head. About.

  In conventional work vehicles such as tractors, a hydraulic lifting device that lifts and lowers a working machine such as a rotary mounted detachably on the rear of the vehicle by operating an operation lever or the like provided in a control unit of the vehicle is placed on a mission case. This hydraulic lifting device includes a cylinder case in which a cylinder is formed by connecting a piston that slides in a cylinder liner to a piston rod attached to a lift crank that is connected to a lift shaft of a work implement; A cylinder head that is attached to the front end of the cylinder case by inlay fitting or the like and has a flow hole for supplying and discharging operating oil such as lubricating oil in the cylinder liner, and further, inlay fitting to the front end of the cylinder head, etc. Supply and discharge control of hydraulic fluid in the hydraulic liner and cylinder head, and hydraulic fluid in the cylinder liner attached to Are those species valve is composed of a control valve case provided. (For example, Patent Documents 1 and 2)

JP 2004-89153 A Japanese Patent Laid-Open No. 2001-211707

However, in such a working vehicle, the cylinder case, the cylinder head, and the control valve case in which the cylinder is installed in the hydraulic lifting device described above are manufactured separately and connected to each other, so that the manufacturing process increases. In addition, since it is necessary to wastely mold these fitting parts, it takes time and labor to manufacture, and there is a problem that costs increase. In addition, since an oil passage communicating with the flow hole of the hydraulic pump or cylinder head is provided in the control valve case, a large space is required at the front of the hydraulic lifting device, and the entire hydraulic lifting device can be made compact. There was also a problem that it was not possible.
Therefore, an object of the present invention is to make it possible to easily assemble a hydraulic lifting device by fitting a cylinder portion formed by integrally forming a cylinder and a cylinder head of a hydraulic lifting device into a cylinder case, and to provide an oil passage in the cylinder portion. Another object of the present invention is to provide a work vehicle that is provided with various valves, saves space by making the hydraulic lifting device compact, and simplifies the manufacturing process to improve productivity and reduce costs.

For this reason, the invention according to claim 1 is the invention, wherein a piston rod having a rear end portion connected to a lift crank is coupled to a rear portion of a piston slidably provided in the cylinder liner inside the cylinder case. A cylinder head provided in front of the cylinder, connected to the cylinder liner and provided with a flow hole through which hydraulic oil flows, and an operation lever provided in the control unit provided in the vicinity of the cylinder head And an operation link case provided with an operation link mechanism for supplying or stopping the hydraulic oil in the cylinder liner by sliding a spool provided on the control valve, In a work vehicle provided with a device on a transmission case, the hydraulic lifting device includes the cylinder and the cylinder head integrally formed. Comprising a cylinder portion formed by, characterized in that the cylinder portion is provided detachably on the cylinder casing.

  According to a second aspect of the present invention, in the work vehicle according to the first aspect, the cylinder portion is within the cylinder portion, and the oil of the hydraulic oil communicated with the flow hole outside the cylinder liner. A road is provided.

  According to a third aspect of the present invention, in the work vehicle according to the first or second aspect, the oil passage is in the cylinder portion, and the supply stop and supply / discharge amount of the hydraulic oil in the cylinder liner are regulated. A slow return stop valve, a check valve for discharging the hydraulic oil in the cylinder liner linked to the spool, and a safety valve are provided.

  According to a fourth aspect of the present invention, in the work vehicle according to the first aspect, the operation link case includes the control valve at a sliding position of the spool.

According to the first aspect of the present invention, a piston rod having a rear end portion connected to a lift crank is connected to a rear portion of a piston that is slidably provided in the cylinder liner, inside the cylinder case. A control valve linked to a cylinder, a cylinder head installed in front of the cylinder and having a flow hole communicating with the cylinder liner and through which hydraulic oil flows, and an operation lever installed in the vicinity of the cylinder head. A hydraulic lifting device for lifting and lowering the work implement, which is provided with an operation link case having an operation link mechanism that slides a spool provided in the cylinder and supplies or stops operating oil in the cylinder liner. the work vehicle provided with the hydraulic lifting device includes a cylinder, a cylinder portion formed by integrally molding a cylinder head, a cylinder portion Since detachably provided on the cylinder case, and as in the prior art cylinder, with a cylinder head need not be manufactured separately, wasteful molding thereof mating portion also does not require, the entire hydraulic lifting device manufacturing process Can be simplified. Moreover, the maintainability of the cylinder part can be remarkably improved. Therefore, it is possible to provide a work vehicle that is improved in productivity and maintainability and is reduced in cost.

  According to the second aspect of the present invention, the cylinder portion is in the cylinder portion, and includes the oil passage for the working oil communicated with the flow hole outside the cylinder liner. It is not necessary to connect the cylinder to the cylinder portion, and the oil passage can be integrally formed in the cylinder portion by effectively utilizing the space in the cylinder portion, so that the manufacturing process can be simplified and the hydraulic lifting device can be made compact. Therefore, it is possible to provide a work vehicle that can improve productivity and reduce costs.

  According to the third aspect of the present invention, the oil passage is provided in the cylinder portion, the slow return stop valve for regulating the supply stop and supply / discharge amount of the hydraulic oil in the cylinder liner, and the cylinder liner linked to the spool. Since a check valve that discharges hydraulic oil and a safety valve are provided, there is no need to connect a separate case with these valves to the cylinder, and the above-mentioned various valves can be integrally formed in the cylinder, simplifying the manufacturing process. And the hydraulic lifting device can be made compact. Therefore, it is possible to provide a work vehicle that can improve productivity and reduce costs.

  According to the invention of claim 4, since the operation link case is provided with the control valve at the sliding position of the spool, it is not necessary to connect the case provided with the control valve separately to the cylinder portion, and is provided in the cylinder portion. It can be integrally formed with an operation link case directly connected to the oil passage and having a spool, so that the manufacturing process can be simplified and the hydraulic lifting device can be made compact. Therefore, it is possible to provide a work vehicle that can improve productivity and reduce costs.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 is a left side view of a wheel tractor according to an embodiment of the present invention, FIG. 2 is a plan view of the tractor, and FIG. 3 is a left side view of a tractor equipped with a rear working machine.

  A tractor 1 which is a working vehicle of this example includes a front wheel 3 and a rear wheel 4 before and after a body frame 2, and a bonnet 5 is formed above the front wheel 3. A clutch housing 7 is disposed, and a transmission case 8 is disposed at the rear of the clutch housing 7. Power from the engine 6 is transmitted to the front wheels 3 and the rear wheels 4. A cabin 9 is provided on the vehicle body frame 2 continuously to the rear part of the bonnet 5. In addition, the tractor 1 may be a lops specification in addition to the cabin specification as described above.

  Next, an operating pedal 10 such as a brake pedal or a clutch pedal, a steering handle 11, a seat 12 and the like are provided in the cabin 9 as a control unit. In addition, left and right fenders (not shown) provided on both sides of the seat 12 include, for example, a main work lever, a sub speed change lever, a PTO speed change lever, and a rear working machine 21 having an arbitrary height via a hydraulic lifting device 22 described later. Various operation levers such as a work machine elevating lever 14 that is moved up and down are projected. Further, a windshield 15, a rear glass 16, a door 17, a roof 18 and the like may be attached to the outer periphery of the cabin 9, respectively.

  The power of the engine 6 is transmitted to a PTO shaft (not shown) protruding forward and backward from the mission case 8, and is driven from the universal joint at the rear end of the vehicle, the lift link 35 and the left and right lower links 36 by driving the PTO shaft. The rear working machine 21 mounted on the rear end of the vehicle is driven via the working machine mounting apparatus 20 such as the three-point link type.

  Next, a specific configuration of the hydraulic lifting device for driving a lift arm for lifting and lowering the rear working machine according to the present invention will be described. 4 is a schematic left side view showing the internal structure of the hydraulic lifting device, FIG. 5 is a right side view of the hydraulic lifting device, FIG. 6 is a plan view of the hydraulic lifting device, and FIG. 7 is a diagram of the hydraulic lifting device showing the arrangement of valves and the like. FIG. 8 is a schematic left side view of the front part of the hydraulic lifting device showing the oil passage in the cylinder part, and FIG. 9 is a perspective view schematically showing attachment of the cylinder case and the cylinder part.

  First, as shown in FIGS. 4 to 6, the hydraulic lifting device 22 placed on the mission case 8 includes a cylinder case 23 that forms an outer frame of the hydraulic lifting device 22 and a front portion of the hydraulic lifting device 22. The cylinder portion 24 includes a cylinder portion 24 that is installed in the cylinder case 23 and has a front end protruding forward from the cylinder case 23 and an operation link case 25 that is installed at the bottom of the front portion of the cylinder case 23.

  This cylinder part 24 is formed by integrally molding a cylinder 26 and a cylinder head 27 by casting or the like. The cylinder part 24 is inserted into a cylinder case 23, for example, as shown in FIG. The same applies to the pedestal d1 provided at four places (appropriate places) on the top, bottom, left and right ends of the front end surface of the cylinder case 23 (such as end positions extending radially from the shaft core at equal intervals) and the front end surface of the cylinder portion 24 in the same manner. The front end surface of the cylinder portion 24 is fixed to the front end surface of the cylinder case 23 with bolts b1 so that the respective holes with the provided pedestal d2 are aligned, and appropriate positions on the upper surfaces of the cylinder case 23 and the cylinder portion 24, respectively. Are aligned with each other, and the upper surface of the cylinder case 23 and the upper surface of the cylinder portion 24 are fixed with bolts b <b> 2. Removable is securable. Further, although not shown, the bottom of the cylinder portion 24 may be fixed to the transmission case 8 or the like by bolt fastening, and the fixing portion or fixing by the bolts b1 and b2 between the cylinder portion 24 and the cylinder case 23 described above. The method is not limited.

  Next, the cylinder 26 is a cavity having an unrestricted shape such as a cylinder, which is provided by punching the rear part of the cylinder part 24 in the front-rear direction of the hydraulic lifting device 22 at the time of casting or the like, and the front end. The cylinder liner 28 is provided with a through hole h in the part, and the piston 29 is inserted into the cylinder liner 28 and is slidable in the cylinder liner 28. The piston 29 includes a piston head 30 and a piston rod 31.

  Further, the rear end portion of the piston rod 31 is connected to a lift shaft 33 via a lift crank 32. Note that left and right lift arms 34 are connected to both ends of the lift shaft 33, the left and right lift arms 34 are connected to the lower link 36, and the rear work machine 21 can be moved up and down by the vertical rotation of the lower link 36. It is said.

  Next, as shown in FIG. 8, the cylinder head 27 constituting the front portion of the cylinder portion 24 includes a space between the cylinder head 27 and the cylinder liner 28 in the cylinder head 27. An oil passage 37 is provided between the upper end portion of the head 27 and the bottom portion near the center of the cylinder portion 24 located below the center of the cylinder liner 28 through the flow hole h of the cylinder liner 28. These oil passages 37 are provided in advance when the cylinder portion 24 is cast. Further, the arrangement position of the oil passage 37 is not limited to the above, and may be within the cylinder head 27.

  In addition, a slow return stop valve 38 for restricting supply and discharge of hydraulic oil in the cylinder liner 28 is provided in the upper part of the cylinder head 27 and in the upper part of the oil passage 37. An adjustment knob 39 for adjusting the stop valve 38 is projected toward the front of the cylinder head 27.

  As shown in FIG. 7, a safety valve 40 is provided in the oil passage 37 located in the vicinity of the slow return stop valve 38, and the oil passage 37 located below the slow return stop valve 38 is provided in the oil passage 37. There is provided a check valve 41 for discharging the hydraulic oil in the cylinder liner 28 to the mission case 8 via piping (not shown). Note that the configurations of the slow return stop valve 38, the safety valve 40, and the check valve 41 are well-known techniques and will not be described in detail.

  Next, an operation link case 25 made of metal or the like is attached to the bottom of the front portion of the cylinder case 23 by welding or the like so as to cover the opening of the oil passage 37. A control valve 42 having a spool 45 is installed in the opening of the oil passage 37 in the operation link case 25, and the entire operation link case 41 is slidable in the front-rear direction. The front part of the control rod 43 which is a part of a link mechanism (not shown) is housed. Further, the control valve 42 communicates with an oil passage (not shown) connected to a hydraulic oil receiving port 44 provided in the operation link case 25 for supplying the hydraulic oil from the transmission case 8 via piping (not shown). .

  The spool 45 is normally biased to a neutral position by an elastic body (not shown) such as a spring. Reference numeral 46 denotes a single-action take-off type pressure measurement plug linked to the safety valve 40 that measures the internal pressure of the hydraulic oil in the oil passage 37 and the cylinder liner 28 installed in the middle of the oil passage 37. It is. In FIG. 8, the cylinder case 23 and the cylinder part 24 are installed horizontally with respect to the operation link case 25. However, the cylinder case 23 and the cylinder part 24 are arranged in the operation link case as shown in FIGS. It may be installed in a slanted position with respect to the front and rear with respect to 25, and the mounting position of the operation link case 25 is not limited to the position described above.

  The front end portion of the control rod 43 is brought into contact with the end portion of the spool 45 of the control valve 42, and the rear end portion of the control rod 43 is linked to the work implement lifting lever 14 and the like via the link mechanism. The configuration of the control valve 42, the spool 45, the control rod 43, the link mechanism, and the like are well-known techniques and will not be described in detail.

  Here, when performing the raising / lowering operation of the rear working machine 21, when the operator of the control unit rotates the working machine raising / lowering lever 14 or the like to the ascending side, the control rod 43 linked to the working machine raising / lowering lever 14 or the like, for example, When the vehicle is slid forward, the spool 45 is also slid forward, and the control valve 42 is opened so that the spool 45 is always lifted from the transmission case 8 by a pump (not shown) through the hydraulic oil inlet 44. The working hydraulic fluid is introduced into the oil passage 37 from the control valve 42, and the check valve 41 linked to the spool 45 is pushed open.

  The hydraulic oil introduced from the oil passage 37 through the check valve 41 into the cylinder liner 28 through the flow hole h slides the piston rod 31 backward as the piston head 30 is pressed backward. The lift shaft 33 is rotated counterclockwise as viewed from the left side through the lift crank 32. As a result, the lower work machine 21 is raised by rotating the lower link 36 upward via the left and right lift arms 34 and the lift link 35 connected to the lift shaft 33.

  At this time, if it is detected by the pressure measurement plug 46 or the like that the pressure in the oil passage 37 and the cylinder liner 28 exceeds the predetermined range due to the introduction of the hydraulic oil, the safety valve 40 is operated, The hydraulic oil in the oil passages 37 and the cylinder liner 28 is discharged, and the pressure in the system is lowered.

  Next, when the operator of the control unit rotates the work implement elevating lever 14 and the like downward, the control rod 43 linked to the work implement elevating lever 14 and the like slides toward the rear of the vehicle, for example. As a result, the spool 45 is also slid rearward, the control valve 42 is closed, the flow of hydraulic oil, which is constantly withdrawn from the transmission case 8 by a pump (not shown) or the like, is blocked from flowing into the cylinder portion 24, and the spool 45 The check valve 41 linked to is opened.

  Since the piston rod 31 slides forward in the cylinder liner 28 through the lift crank 32, the lift shaft 33, and the like due to the weight of the rear work machine 21, the hydraulic oil in the cylinder liner 28 flows through the flow hole h. Is returned to the mission case 8 through the oil passage 37 and the check valve 41, and the rear working machine 21 is lowered.

  When the rear work machine 21 is neutral, the hydraulic oil from the transmission case 8 flows into the control valve 42, pushes open an unloading valve (not shown) and the like and returns into the transmission case 8, and the unloading operation is performed. The hydraulic oil behind the valve is returned into the mission case 8 via the spool.

  Since the hydraulic oil in the cylinder liner 28 is prevented from flowing out of the hydraulic lifting device 22 by the check valve 41 and the safety valve 40, the rear working machine 21 can be held at a constant height. .

  Further, by turning the adjustment knob 39 to adjust the slow return stop valve 38, the oil flows from the oil passage 37 into the cylinder liner 28 through the control valve 42 or the like, or the oil passage 37 and the check from the cylinder liner 28 are checked. Increase or decrease the flow rate of the hydraulic oil flowing out of the hydraulic lifting device 22 through the valve 41 to change the ascent and descent speed of the rear work machine 21 as appropriate, or stop the supply of hydraulic oil into the cylinder liner 28 Can be made.

  And according to the structure of this invention, since the hydraulic raising / lowering apparatus 22 is provided with the cylinder part 24 which integrally molded the cylinder 26 and the cylinder head 27, the conventional cylinder 26 and the cylinder head 27 are each separated. It is not necessary to manufacture, and unnecessary forming of these fitting portions is not required, and the manufacturing process of the entire hydraulic lifting device 22 can be simplified.

  In addition, since the oil passage 37 is formed in advance in the cylinder head 27 of the cylinder portion 24, there is no need to connect a case provided with the oil passage 37 to the cylinder portion 24, and the space in the cylinder portion 24 is eliminated. The oil passage 37 can be integrally formed in the cylinder portion 24 by effectively utilizing the above, the manufacturing process can be simplified, the hydraulic lifting device 22 can be made compact, and the degree of freedom ahead of the hydraulic lifting device 22 is increased. be able to.

  Furthermore, since various valves such as the slow return stop valve 38, the safety valve 40, and the check valve 41 are also installed in the cylinder head 27, it is necessary to separately provide a valve case at the front part of the conventional hydraulic lifting device 22. The entire hydraulic lifting device 22 can be configured compactly, and the degree of freedom ahead of the hydraulic lifting device 22 can be increased.

  Then, in order to attach the operation link case 25 having the control valve 42 to the sliding position of the spool 45 to the cylinder case 23, a valve case having the control valve 42 is separately provided at the front portion of the conventional hydraulic lifting device 22. The operation link case 25 can be attached to the cylinder case 23 in accordance with the end position of the oil passage 37, and the degree of freedom of the attachment position of the operation link case 25 can be improved, and the position of the oil passage 37 can be changed. It can be easily handled.

  As described above in detail, the tractor 1 of this example has the rear end connected to the lift crank 32 at the rear of the piston 29 slidably provided in the cylinder liner 28 inside the cylinder case 23. A cylinder 26 formed by connecting a piston rod 31, a cylinder head 27 provided in front of the cylinder 26, communicated with a cylinder liner 28, and provided with a flow hole h for circulating hydraulic oil, and installed in the vicinity of the cylinder head 27. A control rod 43 that supplies or stops hydraulic oil into the cylinder liner 28 by sliding a spool 45 provided on the control valve 42 in conjunction with the work equipment lifting lever 14 (operation lever) of the control unit. A hydraulic mechanism for raising and lowering the rear work machine 21 (work machine), including an operation link case 25 having a link mechanism). The device 22, provided on the transmission case 8, a hydraulic lifting device 22 is provided with a cylinder 26, a cylinder portion 24 formed by integrally molding a cylinder head 27.

  Further, the cylinder portion 24 is provided with an oil passage 37 for hydraulic oil communicated with the flow hole h inside the cylinder portion 24 and outside the cylinder liner 28, and the oil passage 37 is provided in the cylinder portion 24. A slow return stop valve 38 for restricting the supply stop and supply / discharge amount of the hydraulic oil in the cylinder liner 28, a check valve 41 for discharging the hydraulic oil in the cylinder liner 28 linked to the spool 45, and a safety valve 40; The operation link case 25 includes a control valve 42 at the sliding position of the spool 45.

  In the above example, a wheel tractor (agricultural work vehicle) has been described as an example of a work vehicle. However, the present invention is not limited to this, and a backhoe or a bulltozer can be used as a construction work vehicle in addition to a crawler tractor. For example, the present invention can be applied to any work vehicle including a work machine lifting device that lifts and lowers a work machine attached to the vehicle.

It is a left view of the wheel type tractor concerning one example of the present invention. It is a top view of a wheel type tractor. It is a left view of the tractor equipped with the rear work machine. It is a left side schematic diagram which shows the internal structure of a hydraulic lifting apparatus. It is a right view of a hydraulic lifting apparatus. It is a top view of a hydraulic lifting device. It is a front view of the hydraulic lifting apparatus which shows arrangement | positioning, such as a valve | bulb. It is the left side surface schematic diagram which expanded the hydraulic lifting / lowering apparatus front part which shows the oil path in a cylinder part. It is a perspective view which shows typically attachment of a cylinder case and a cylinder part.

Explanation of symbols

21 Rear working machine 22 Hydraulic lifting device 23 Cylinder case 24 Cylinder part 25 Operation link case 26 Cylinder 27 Cylinder head 28 Cylinder liner 29 Piston 30 Piston head 31 Piston rod 32 Lift crank 33 Lift shaft 34 Left and right lift arm 35 Lift link 36 Lower link 37 Oil passage 38 Slow return stop valve 39 Adjustment knob 40 Safety valve 41 Check valve 42 Control valve 43 Control rod 44 Hydraulic oil inlet 45 Spool 46 Pressure measurement plug b1, b2 Bolt h Flow hole

Claims (4)

A cylinder formed inside a cylinder case, in which a piston rod having a rear end connected to a lift crank is connected to a rear part of a piston slidably provided in a cylinder liner, and installed in front of the cylinder. A cylinder head that is connected to the cylinder liner and provided with a flow hole for circulating hydraulic oil, and a spool provided on the control valve that slides in connection with an operation lever that is provided in the vicinity of the cylinder head and that is provided on the control unit. An operation link case provided with an operation link mechanism for supplying or stopping the hydraulic oil in the cylinder liner, and a hydraulic vehicle for raising and lowering a work implement on a transmission vehicle. the hydraulic lifting device is provided with the cylinder, the cylinder portion formed by integrally molding with the cylinder head, the sheet A work vehicle, characterized in that the Sunda unit detachably provided on the cylinder casing.   2. The work vehicle according to claim 1, wherein the cylinder portion includes an oil passage for the hydraulic oil communicated with the flow hole inside the cylinder portion and outside the cylinder liner.   The oil passage has a slow return stop valve that regulates the supply stop and supply / discharge amount of the hydraulic oil in the cylinder liner, and discharges the hydraulic oil in the cylinder liner linked to the spool. The work vehicle according to claim 1, further comprising: a check valve that performs a check valve and a safety valve.   The work vehicle according to claim 1, wherein the operation link case includes the control valve at a sliding position of the spool.

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